Cross-linking of polymers and foams thereof

The invention comprises a process comprising: (a) forming a polymer mixture comprising at least one polyolefin prepared using a single point catalyst and at least one poly (sulfonyl azide) crosslinking agent in an amount sufficient to form at least crosslinking; (b) shaping the resulting mixture; and (c) heating the formed shaped mixture to a temperature of at least the decomposition temperature of the crosslinking agent. The steps can be performed in any sequence and optionally include sub-steps. Preferably, in step (b) the polymer mixture is softened or melted to form, or step (b) is thermoformed; compression molding, injection molding, extrusion, casting, blow molding, blow molding, profile extrusion, spinning, other molding, or combination thereof; or (c) foaming step; or step (a) comprises forming a foamable molten polymer material by mixing and heating a degradable chemical blowing agent and other components of the polymer mixture; and step (b) removing the foamable molten polymer material from a die; or step (a) comprises the following sub-steps: (i) suspending the individual polyolefin particles in a liquid medium in which they are insoluble; (ii) impregnating poly (sulfonyl azide) crosslinking agent in an amount capable of crosslinking the particles at superatmospheric pressure and at a temperature above the softening point of the polymer; and (b), (c) or a combination thereof: (iii) rapidly discharging the particles to a pressure lower than in step (ii) to form foam beads, or (iv) cooling the particles and then expanding them with at least one heated gas; or (a) mixing at least one polyolefin, a poly (sulfonyl azide) crosslinking agent and a chemical blowing agent to form a mixture; step (b) comprises a first sub-step forming a slice from the mixture; step (c) comprises heating the mixture in a container such that the crosslinking agent forms a crosslinking in the polymer material and the foaming agent breaks down; and both step (b), step (c), or a combination of these, by releasing the pressure in the mold.

52382 expanding the slice that occurs in the sub-step; or step (b) comprises the first sub-step of forming a sheet from the polymer mixture comprising a poly (sulfonyl azide) crosslinking agent in an amount sufficient to cross-link; step (c) comprises heating the plate sufficiently to form cross-linking; Step (b) can also be used at a temperature above the softening point of the polymer and at a certain pressure.₂ the impregnation second sub-step; and the third step of pressure relief which will result in the nucleation of the bubbles and a certain expansion or combination of these in the plate. More preferably, the crosslinking agent is included in the polymer mixture in the molten processing equipment, which is preferably an extruder. The single point catalyst is preferably of limited geometry or metallocene catalyst, but optionally a conventional Ziegler Natta Ti / MgCl₂ another transition metal catalyst such as a vanadium catalyst without catalyst. At least one polyolefin, preferably a polyethylene homopolymer, an ethylene copolymer having at least one alpha olefin comonomer selected from monomers having from 3 to 20 carbon atoms; an elastomer polymer; an ethylene / alpha olefin / diene terpolymer or interpolymer; can be substantially linear ethylene polymer or a combination thereof. The at least one polyolefin preferably has a molecular weight distribution of less than about 3.5; more preferably the polyolefins all have this MWD. Preferably, the polymer mixture is at least one other which is separated by having at least one polyolefin made using at least about 5 percent single point catalyst, having a density different from the polyolefin, a different molecular weight, the use of a different catalyst in polymerization, a different chemical composition, and combinations thereof. is a blend containing polymer. The polyolefin is made using a single point catalyst and is preferably present in an amount of at least about 10 percent by weight of the blend, a polyethylene or an ethylene alpha olefin copolymer, and the other polymer is preferably greater than at least about 10 percent by weight, molecular weight (Mn). or selected from the group consisting of ethylene vinyl acetate copolymer, styrene diene block copolymer, natural rubber, isoprene rubber, or a combination thereof. The at least one poly (sulfonyl azide) preferably has the structure XRX; each X in this structure, SO₂N₃and R represents an unsubstituted or inert substituted hydrocarbyl, hydrocarbyl ether or silicon-containing group; poly (sulfonyl azide) having at least 3 and less than about 50 carbon, silicon or oxygen atoms among the sulfonyl azide groups; and wherein R includes at least one aryl group among the sulfonyl groups, or is preferably used in an amount greater than about 0.5 percent of the total weight of the total polymer mixture or reacts at least at the decomposition temperature and at a temperature greater than about 185 ° C.

»

52382

The invention also encompasses all compositions obtainable by the process of the invention and all products formed therefrom. The products are preferably thermoformed of any composition of the invention; compression molding, injection molding, extrusion, pouring, blow molding, blow molding, profile extrusion, spinning, foaming. The invention also includes the use of any composition of the invention in any thermoforming, press molding, injection molding, extrusion, casting, blow molding, blow molding, profile extrusion, spinning, foaming process, or a combination thereof. .

The homopolymers and copolymers (interpolymers) having a narrow comonomer distribution, narrow molecular weight distribution or a combination thereof, having at least one CH bond capable of reacting with a compound capable of being introduced into a carbon-hydrogen (CH) bond, prepared using the single point catalyst of the invention, terpolymers, oligomers, and other types of polymers, including polyolefins. Examples of such homopolymers and copolymers are copolymers of ethylene with one or more alpha olefins (C3 to C20), including LLDPE (linear low density polyethylene); unsaturated ethylene copolymers (EPDM or EODM, ie ethylene-propylene-diene or ethylene-octene-diene) or other polymers such as linear high density polyethylene.

The practice of the invention can also be applied to blends of two or more polymers, in particular polyethylene, ethylene alpha olefin copolymers or combinations thereof. At least one of these polymers is prepared using a single point catalyst and these polymers have different average molecular weights. In a two polymer component blend, the high average molecular weight is preferably about 10 percent greater than the low average molecular weight. When more than two polymer components are present, the highest and lowest molecular weight is about 10 percent different from the medium molecular weight component. Although the individual at least one component has a MWD of less than about 3, the resulting blend will thus optionally have an Mw / Mn of greater than 3.0 or 3.5. If the high average molecular weight of one polymer component is 30 percent or greater than that of the other component of the blend, the blend generally exhibits multiple peaks in gelatin permeation chromatography (GPC) curve analysis. The term “two-puffed” refers to polymers that exhibit two peaks in the (GPC) curve in the graphical representation of the data of the appropriate analysis to measure the discussed feature.

52382 is used to specify. These distributions are seen as statistical. Thus, when there is a peak, the dispersion has a mode and is unimodal. The two peaks are two-mode. Two or more of them are multi-mode. The blend is optionally an in-reactor blend or a blend formed by passing the first polymer made in the first reactor through the second reactor from which the second polymer is produced. Alternatively, the blend may optionally be made using two or more single point catalysts. Those skilled in the art will recognize that peaks generally have overlying areas, and sometimes mathematical analysis is required to separate multi-mode curves from common irregular curves.

Given the preferred molecular weight distributions (MWD) (Mw / Mn) of the present invention, these distributions preferably indicate the MWD of the at least one component represented by a peak of the GPC curve.

Preferred polymers for use in the practice of the invention are polymers prepared from ethylene, preferably ethylene in combination with other polymerizable monomers. These monomers are alpha olefins and other monomers having at least one double bond.

Alpha olefins having more than 2 carbon atoms are propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-nonene, 1-decene, 1-unidecene, 1-dodecene and 4-methyl-1-pentene, 4 -methyl-1-hexene, 5methyl-1-hexene, vinylcyclohexene.

The interpolymers which may be used optionally and in a preferred embodiment in the practice of the invention include monomers having at least two double bonds, preferably diene or triane. Suitable diene or triane comonomers include 7-methyl-1,6-octadiene, 3,7-dimethyl-1,6-octadiene, 5,7dimethyl-1,6-octadiene, 3,7,11-trimethyl-1,6,10 -octatriene, 6-methyl-1,5-heptadiene, 1,3-butadiene, 1,6-heptadiene, 1,7-octadiene, 1,8-nonadiene, 1,9-decadiene, 1,10-andecadiene, bicyclo [2.2.1] hepta-2-5-diene (norbomadiene), tetracyclododecene or mixture thereof, preferably butadiene, hexadiene or octadiene, more preferably 1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl- 1,4-hexadiene, disildopentadiene, bicyclo [2.2.1] hepta-2-5-diene (norbomadiene) and 5ethylidene-2-norbomer (ENB).

Polyolefins are formed by means in the art. Alpha-olefin monomers and optionally polymerizable monomers by adding another are disclosed in US Pat. 3,645,992 (Elston), 4,937,299 (Ewen et al), 5,218,071 (Tsutsui et al), 5,278,272, 5,324,800,

T * ³ 52382

No. 5,084,534, 5,405,922, 4,588,794, 5,204,419, using metallocene and other single point catalysts under the conditions known in the art.

to

Preferred polymers in the practice of the invention are elastomeric. “Elastomeric polymer” refers to a polymer that can be stretched to at least twice its length by applying tensile force and can return to its approximate original size and shape after removal of the tensile force. Elastic recovery of the elastomer polymer prior to ebonitization is generally at least 40 percent, preferably at least 60 percent, and more preferably at least 8 percent, after extending 100 percent of the sample original size at 20 ° C according to the ASTM 4649 procedure. .

Elastomer polymers suitable for use in the present invention are ethylene / α-olefin interpolymers. "A-olefin" means a hydrocarbon molecule or a substituted hydrocarbon molecule (i.e., hydrogen and one or more atoms other than carbon, such as halogen, oxygen, nitrogen, etc.). a hydrocarbon molecule); the hydrocarbon molecule comprises (i) only an ethylene unsaturation, the unsaturation being between the first and second carbon atoms, and (ii) at least three carbon atoms, preferably 3 to 20 carbon atoms, in some cases preferably 4 to 8 carbon atoms. Preferred α-olefin extracts from which the elastomers used in the present invention are prepared are propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-dodecene, and mixtures of two or more of these monomers.

Preferred elastomer polymers which can be used in the practice of the present invention are ethylene / aolefin interpolymers, in particular about 0.9 g / cm 2³having a density less than. Preferred ethylene interpolymers are ethylene / α-olefin copolymers; ethylene / aolefin / diene terpolymers; and interpolymers of ethylene and other monomers which can be copolymerized with one or more ethylene. Such polymers are described in (a) U.S. Pat. No. 3,645,992; and (b) for example, U.S. Pat. And homogeneous linear ethylene polymers such as those made using single point catalyst in a batch reactor having a relatively high olefin concentration as described in U.S. Pat. Nos. 5,026,798 and 5,055,438. These polymers are commercially available. Commercially available homogeneous linear ethylene polymers are described in Mitsui Petrochemical Industries. Ltd. and the Exxon Chemical Co. EXACT ™ polymers.

52382

1.

-J?

The elastomer polymer is substantially amorphous. The term 'substantially amorphous' means that the polymer has a degree of crystallization of less than about 25 percent. The elastomeric polymer preferably has a degree of crystallization of less than about 15 percent.

The elastomeric polymer may be the product of a single polymerization reaction, or it may be a polymer blend formed by the physical blending of polymers obtained from different polymerization reactions and / or using a mixed polymerization catalyst.

Particularly preferred ethylene / α-olefin interpolymers are ethylene / 1-octene, ethylene / 1-hexene, ethylene / 1-butene, and ethylene / propylene copolymers produced by a single point catalyst of limited geometry. A process for making these copolymers is described in US Pat. U.S. Patent No. 5,141,662; 5,272,236 and U.S. Pat. U.S. Patent No. 5,141,662; No. 5,278,272. These ethylene interpolymers are preferably substantially linear olefin polymers with long chain branches. The substantially linear olefin polymers can be manufactured by gas phase, solution phase, high pressure or slurry polymerization. These polymers are preferably manufactured by solution polymerization. Substantially linear ethylene polymers (SLEP) are available from The Dow Chemical Company under the trade name AFFINITY ™ and from DuPont Dow Elastomers LLC under the trade name ENGAGE ™.

In one embodiment, the starting material polyolefins are preferably substantially linear ethylene polymers (SLEP). The substantially linear ethylene polymers (SLEP) are homogeneous polymers with long chain branches. US Pat. 5,272,236 and 5,278,272.

SLEPs are Affinity ™ polyolefin plastomers (POP) commercially available from The Dow Chemical Company (Eng) and Engage ™ polyolefin elastomers (POE) commercially available from DuPont Dow Elastomers LLC. These polymers were manufactured with Insite ™ Process and Catalyst Technology. Engage ™ POEs that may be used are SM 8400, EG 8100, and CL 8001, and Affinity POPs that may be used are FM-1570, HM-1100, and SM-1300, each commercially available from The Dow Chemical Company. SLEPs are described in European patent application no. 416-815-A may be prepared by solution, slurry or gas phase, preferably solution phase polymerization, in the presence of a catalyst of limited geometry of one or more optional aolefin comonomers with ethylene.

The substantially linear ethylene / .alpha.-olefin polymers are preferably disclosed in U.S. Pat. US Patent Application 5,132,380 and July 3, 1990;

JT: Τ * 52382

No. 545,403. Catalysts of limited geometry, such as those disclosed in U.S. Pat. U.S. Pat. The monocyclopentadienyl transition metal olefin polymerization catalyst contemplated in U.S. Pat. No. 5,026,798 is also suitable for preparing the polymers of the invention as long as the reaction conditions are as follows.

Suitable cocatalysts that may be used herein include, but are not limited to, the polymer or oligomer aluminoxane, particularly methyl aluminoxane, and inert, compatible, non-coupling ion-forming compounds. Preferred co-catalysts are inert, non-associative boron compounds.

The term "continuous process" means a process in which the reaction participants are added continuously and the product is continuously taken so as to achieve about 10 invariants (i.e., reactants and a substantially constant concentration in the product). Polymerization conditions for manufacturing substantially linear ethylene / .alpha.-olefin polymers of the invention are generally those used in the solution polymerization process, although the application of the invention is not limited thereto. It is contemplated that slurry and gas phase polymerization processes may also be used provided that the correct catalysts and polymerization conditions are used.

For the formation of cross-linking of substantially linear olefin polymers and copolymers according to the invention, U.S. Pat. Multiple reactor polymerization processes may also be used, as disclosed in US Pat. No. 3,914,342. In one of the reactors, these reactors may be used in series or in parallel using at least one limited geometry catalyst.

The term "substantially linear" refers to an ethylene polymer having long chain branches in which the polymer backbone is replaced by an average of 0.01 to 3 long chain branches / 1000 carbons, in addition to short chain branches that may be attached to homogeneous comonomer introduction. Preferred substantially linear polymers which may be used in the invention are replaced by 0.01 long chain branches / 1000 carbon to 1 long chain / 1000 carbon and more preferably 0.05 long chain branches to 1 long chain branch / 1000 carbon.

In contrast to the term "substantially linear", the term "linear" means that there are no measurable or verifiable long chain branches in the polymer, ie the polymer is replaced by an average of less than 0.01 long chain branches / 1000 carbons.

52382

For ethylene / α-olefin interpolymers, "long chain branching" (LCB) means a longer chain than the short chain branch resulting from the introduction of the α-olefin (s) into the polymer backbone. Each long chain branch has the same comonomer distribution as the polymer backbone and can be as long as the polymer backbone to which it is attached.

The empirical effect of long chain branching in the substantially linear ethylene / α-olefin interpolymers used in the invention is evident in its improved rheological properties. These properties are measured and expressed here in terms of gas extrusion rheometry (GER) results and / or molten flow I10 / I2 increments.

Presence of short chain branching of up to 6 carbon atoms in ethylene polymers 10 ¹³C can be determined using nuclear magnetic resonance (NMR) spectroscopy and measured using the method described by Randall (Rev. Macromol. Chem. Phys., C.29. Vol. 2 & 3, pp. 285-297).

Available as a practical topic ¹³C nuclear magnetic resonance (NMR) spectroscopy cannot distinguish a long chain constant length above 6 carbon atoms. However, there are other known techniques used to determine the presence of long chain branches in ethylene polymers, including ethylene / 115 octene interpolymers. Two such methods are combined gelatin permeation chromatography (GPC-LALLS) with low angle laser light emitter detector and combined gelatin permeation chromatography (GPC-DV) with differential viscometer detector. The use of these techniques for long chain branch detection and the underlying theories are well studied in the literature. See, for example, Zimm, GH and Stockmayer, WH, J. Chem. Phy., 17, 1301 (1949) and Rudin A, Modern Methods for Polymer Determination, John Wiley & amp; Sons, New York (1991), p. 103-112.

A. Willen de Groot and P. Steve Chum of The Dow Chemical Company; In St. Louis, October 4, 1994, at the Conference of the Federation of Analytical Chemistry and Spectroscopy Sayings (FACSS) presented data proving that GPC-DV is a technique that can be used to measure the presence of long chain branches in SLEPs. Specifically, deGroot and Chum were able to measure the long chain branch level measured in homogeneous substantially linear homopolymer samples using the Zimm-Stockmayer equation.¹³The long chain branch measured using C NMR.

52382

Furthermore, deGroot and Chum found that the presence of octene does not alter the hydrodynamic volume of the polyethylene samples in solution, and thus the increase in molecular weight that can be attached to the octene short chain branches can be calculated by knowing the octene mole percentage in the sample. By solving its contribution to the increase in molecular weight that can be attached to 1-octene short chain branches, deGroot and Chum have shown that GPC-DV can be used to measure the level of long chain branches in substantially linear ethylene / octene copolymers.

DeGroot and Chum log (M as determined by GPC)_whas shown that the graph of log (D) as a function of) can be compared to the long chain branching properties (not the measure of long branching) of the SLEPs with high pressure, high branched low density polyethylene (LDPE) and manufactured Ziegler type catalysts or homogeneous polymers such as titanium compounds. is different from ethylene polymers produced using ordinary catalysts such as hafnium and vanadium compounds.

Furthermore, SLEPs are characterized in that they have:

(a) molten yield ratio I10 / I2> 5.63, (b) molecular weight distribution Mu / M determined by gelatin permeation chromatography and defined by the following equation_n:

(Mw / Mn) <(I10 / I2) -4.63, (c) 4 x 10 as determined by gas extrusion rheometry at the beginning of wholesale melting.⁶dyn / cm²the critical shear rate at the start of surface melt fracture for critical shear unit stress or SLEP greater than at least 50% greater than the critical shear rate at the beginning of surface melt fracture for linear ethylene polymer; SLEP and linear ethylene polymer contain the same comonomer or comonomers; the linear ethylene polymer is an I, each of which is within 10 percent of SLEP.₂Has a density of Λ, Λ1 „and the corresponding critical shear rates of SLEP and linear ethylene polymer were measured at the same melting temperature using a gas extrusion rheometer; and (d) a single differential scanning calorimetry (DSC) melting peak between -30 and 150 ° C.

Generally, for linear ethylene polymers, the ratio I 10 / I 2 is at least about 5.63, preferably at least about 7, particularly at least about 8 and above. The compositions used in the compositions of the invention

52382 For substantially linear ethylene / .alpha.-olefin polymers, the I10 / I2 ratio indicates the long chain branching ratio, the greater the I10 / I2 ratio, the more long chain branching is present in the polymer. Generally, the substantially linear ethylene / α-olefin polymers have an I 10 / I 2 ratio of at least about 5.63, preferably at least about 7, particularly at least about 8 and above, and can be as high as about 25.

The substantially linear olefin polymers for use in the present invention preferably have a melt index of at least about 0.1 grams / 10 min (g / 10 min), more preferably at least about 0.5 g / 10 min, and more preferably at least about 1 g / 10 min. and preferably grows up to about 100 g / 10 min, more preferably about 50 g / 10 min, and in particular up to about 20 g / 10 min.

The determination of critical shear rate and critical shear stress in relation to other rheological properties such as melt crushing and rheological treatment index (PI) is carried out using a gas extrusion rheometer (GER). Gas extrusion rheometer by M. Shida, RN Shroff and LV Cancio in Polymer Engineering Science, Vol. 11, p. 770 (1977), and by John Dealy, Van Nostrand Reinhold Co., et al. publication (1982) p. 97-99. GER tests are generally carried out using a 20: 1 L / D die of 0.0754 mm diameter with an inlet angle of 180 ° C at a nitrogen pressure of 250 to 5500 psig (1724 to 37921 kPa) at 190 ° C. For the SLEPs described herein, PI is a 2.15 x 10 material of a material measured by GER.⁶ dyn / cm² apparent viscosity under apparent shear unit stress (in kpuvase). SLEPs for use in the invention are ethylene interpolymers and have a P1 of 0.01 kpuvase (1 Pa / S) to 50 kpuvase (5000 Pa / S), preferably 15 kpuvase (1500 Pa / S) or less. The SLEPs used herein are each comprised of an I2, / «/ Μ within 10 percent of the SLEPs._η and a density (either polymerized by Ziegler polymer or linear uniformly branched polymer as described in US Patent No. 3,645,992) has a P1 of less than or equal to 70 percent PF of the linear ethylene polymer.

The rheological behavior of SLEPs can also be described by the Dow Rheology Index (DRI). This index refers to a polymer as “the normal relaxation time as the result of long chain branching”. (See S. Lai and GW Knight ANTEC 93 Proceedings, New Rules for the Structure / Rheology Relationship of INSOL ™ Technology Polyolefins (SLEP)-Ethylene / α-Olefin Copolymers, New Orleans, La, May 1993). DRI values ​​are polymers without any measurable long chain branching (e.g., available from Mitsui Petrochemical Industries).

52382

Tafiner ™ products and Exact ™ products available from Exxon Chemical Company). In general, for low to medium pressure ethylene pobmers (especially at low densities), DRI provides improved joints compared to those obtained by melt elasticity and melt flow rates of the same issues in high shear fluid. For SLEPs that may be used in the present invention, the DRI is preferably at least 0.1 and in particular at least 0.5 and more preferably at least 0.8. DRI can be calculated by the following equation.

DRI- (3652879 * το¹’⁰⁰⁵⁴⁹ / η₀-1)/10

In this equation το is the characteristic relaxation time of the material and η₀ zero shear viscosity of the material. Both τ₀ and ηο are “best fit ine values ​​to the Cross equation, ie η / ηο = 1 / (1+ (γ * το)¹')

In this equation n is the power rule index of the material and η and γ are the measured viscosity and shear rate, respectively. Basic determination of viscosity and shear rate data A Rheometric Mechanical Spectrometer (RMS800) under 0.1 to 100 radians second dynamic scan mode at 190 ° C and 1,000 psi to 5,000 psi (6.89) corresponding to shear stress of 0.086 to 0.43 MPa to

34.5 MPa) extrusion pressure, 190 “C, 0.0754 mm diameter 20.1 L / D molded gas

Extrusion rheometer (GER). Specific material determinations can be carried out at 140 to 190 ° C to accommodate variations in the melt index as needed.

The graph of apparent shear stress to apparent shear rate is used to describe the melt fracture phenomenon and to quantify the critical shear rate and critical shear stress of ethylene polymers. According to Ramamurthy in Journal of Rheology, 30 (2), 337-357, 1986, extrusion product irregularities observed above a certain critical flow rate can be roughly classified into two main types: surface melt fracture and gross melt fracture.

Surface melt fracture occurs in unchanging flow conditions and extends in detail from the loss of reflective film appearance to the most extreme form, the “smooth and glossy face.. The initiation of surface melt fracture (OSMF) as determined using GER described above is defined as loss of appearance in the extrusion product. The loss of appearance of the extrusion product is the point at which the surface hardness of the extrusion product can only be detected at 40X magnification. For SLEPs, the critical cutting speed at the start of surface melt fracture is essential.

-x

J *

52382 Same as I₂ and M_x/ M_nis at least 50 percent greater than the critical shear rate at the onset of surface melt fracture of a linear ethylene polymer having a viscosity.

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Gross melt fracture occurs under unstable extrusion flow conditions and extends in detail from regular (alternatively hard and smooth, helical, etc.) to random sprains. To maximize the performance characteristics of films, coatings and molds to ensure they are commercially acceptable, they must be minimal even if surface defects are present. SLEPs used in the invention, especially those having a density greater than 0.910 g / centimeter cube, critical shear stress at the onset of total surface breakage 4 x 10⁶ dyn / cm²is greater than. The critical shear rate at the onset of surface melt fracture (OSMF) and at the onset of integral melt fracture (OGMF) will be used according to changes in surface hardness and shape of extrusion products obtained from a GER.

A feature of the SLEPs used in the invention is that they have a single DSC melting peak. The single melting peak is determined using a differential scanning calorimeter standardized with indium and deionized water. The method contains 3-7 mg of sample size, the first temperature of about 180 ° C maintained for 4 minutes, the cooling to -30 ° C maintained for 3 minutes at 10 ° C / min and the temperature of 140 ° C at 10 ° C / min. second heat ikinci. The single melting peak is taken from the “second heat” curve of the heat flow relative to the temperature. The total fusion temperature of the polymer is calculated from the area under the curve.

For polymers having a density of 0.875 g / centimeter to 0.910 g / centimeter cubic meters, the low melting peak is less than 12 percent, typically less than 9 percent, and more typically less than 6 percent of the total fusion heat of the polymer, depending on the equipment sensitivity. a shoulder or a hump. Such a formation can be observed in other homogeneously branched polymers such as Exact ™ resins and is distinguished on the basis of the slope of the single melting peak that changes monotonously along the melting zone of the formation. Such a formation occurs within 34 ° C of the single melting peak, typically within 27 ° C, and more typically within 20 ° C. The fusion heat that can be attributed to the formation can also be determined by the specific integration of the associated area of ​​the heat stream relative to the temperature curve.

SLEPs are analyzed in a Waters 150 ° C high temperature chromatography unit equipped with differential refractometer and three column mixed porosity. Columns Polymer

52382

Laboratories.³, ΙΟ⁴, 10⁵ and 10⁶ packed with pore sizes. The solvent is 1,2,4-trichlorobenzene. Sample solutions of 3 weight percent of this solvent are prepared for injection. The flow rate is 1.0 ml / min, the unit operating temperature is 140 ° C and the injection size is 100 microliters.

In order to determine the molecular weight relative to the polymer backbone, the elution volumes are deduced using narrow molecular weight dispersed polystyrene standards (Polymer Laboratories). Equivalent polyethylene molecular weight, Μ ^^ η = a * (M_poI_istI_reindeer)^bMark-Houwink polyethylene and polystyrene coefficients (as described by Williams and Ward in Journal of Polymer Science, Polymer Letters, Vol. 6, p. 621, 1968).

In this equation a^z= 0, 4316 and b = 1. Weighted average molecular weight M_w It is calculated in the usual way according to the formula:

M_w = Σ (w1 x M1)

In this equation, w 1 and M 1 are weight fraction and molecular weight, respectively, of part 1 separated from the GPC column.

The density of linear or substantially linear ethylene polymer (measured according to ASTM-D7922) for use in the present invention is generally about 0.95 g / cm 2.³is less than. The density is preferably at least about 0.85 g / cm³ and in particular at least about 0.86 g / cm³and preferably about 0.94 g / cm.³up to about 0.92 g / cm.³up to. When crosslinked resins are used for extrusion and injection molding, the density of the polymer is preferably at least 0.855 g / cm³better yet, at least 0.865 g / cm³ and even better yet at least 0.870 g / cm³and preferably 0,900 g / cm.³up to 0.885 g / cm³up to and even better 0.880 g / cm³up to. The most preferred density is primarily determined by the desired modulus of elasticity or elasticity in the molded article. The density remains substantially constant during crosslinking formation according to the present invention.

The ethylene polymers crosslinked according to the practice of the invention are optionally any interpolymer of ethylene and at least one α-olefin. Suitable α-olefins are represented by the following formula:

CHINA₂-CHR

52382

Wherein R is a hydrocarbyl radical. R generally has one to 20 carbon atoms. Α-olefins suitable for use as a comonomer in the solution gas phase or slurry polymerization process or combinations thereof are 1-propylene, 1-butene, 1-isobutylene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene and 1-heptene. -octene and tetrafluoroethylene, vinyl benzocyclobutane and cycloalkenes are other types of monomers such as, for example, cyclopentene, cyclohexene, cyclooctene and norbomen (NB). Preferably, α-olefin will be 1-butene, 2-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene or NB or mixtures thereof. More preferably the α-olefin will be 1-hexene, 1-heptene, 1-octene or mixtures thereof. Most preferably α-olefin will be 1-octene. The ethylene polymer formed by crosslinking according to the present invention is preferably SLEP.

These interpolymers preferably contain at least about 2 weight percent, more preferably at least about 5 weight percent α-olefin.

The polyolefin is a homopolymer, copolymer or interpolymer. Preferably, the homopolymer or copolymer comprises ethylene repeating units. Comonomer content in polyethylene copolymers¹³It is greater than about 1 weight percent and more preferably greater than 3 weight percent of any monomer copolymerizable with ethylene as determined by C NMR (carbon 13 nuclear magnetic resonance), preferably an alpha olefin or cyclin olefin. Such an olefin preferably has less than about 20 carbon atoms, more preferably about 2 to 18 carbon atoms. The comonomer content is at least one ethylene polymerizable comonomer, preferably less than 4 comonomers, more preferably less than 2 such comonomers.

In one embodiment, preferred polymers for starting materials which may be used in the practice of the invention are slurry high density polyethylene homopolymers made using single point catalysts. When the polymer has a narrow molecular weight distribution (MWD), that is MWD is preferably about 3.5 M_xvi/ M_nless than 3.0 M ^ AV less than 2.5 M_vv/ M_ndensity of less than about 0.945g / ml. In the blend of two or more polymers comprising at least one HDPE made using a single point catalyst, at least one of the components is preferably all of the components, preferably less than 3.5, more preferably less than 3.0, most preferably less than 2.5. It has MWD. In these cases, although the composition is a preferred embodiment, it optionally has a total MWD of greater than 3.5. Polymer blends are generally formed optionally to optimize, for example, workability and mechanical properties. Blend

52382 It is within the skill of the art to form compositions, for example, two or more different molecular weight polymer with single catalyst may be blended in a reactor. The melt index (MI) of the starting material is preferably at least about 0.01 g / 10 min, more preferably 0.1 g / 10 min min b; because a MI, generally less than 0.01 g / 10 minutes, is associated with a high viscosity which is difficult to shape in product form when melted. Preferably, the MI is less than about 100 g / 10 minutes, more preferably less than about 20 g / 10 minutes, since the polymer having a melt index greater than 100 g / 10 minutes generally has a weak stiffness. These polymers exhibit good stability in the following properties (a) the mechanical properties of the formed product, also referred to herein as the final component, and (b) the processability of the polymer in the shaping step (s).

Most preferred polymers as starting material for the present invention are narrow MWD of a blend composition or at least one component of a blend composition (ie less than 3.5, more preferably less than 3.0, most preferably 2.5 '). less than one Mw / Mn). They can be produced using at least one C3-C20 olefin comonomer. Most preferred for the copolymer is C 3 -C 1 O. In the starting material, about 0.5 to 40 mole percent comonomer as determined by ASTM 5017 is preferred. The preferred melt index for the starting material depends on the application; however, the preferred melt index is about 0.01 to 20 g / 10 minutes. Commercially available polymers of this category include TAFMER ™ polymer available from Mitsui Petrochemical Industries, EXACT ™ polymer available from Exxon Chemical Company, AFFINITY ™ polyolefin plastomer available from The Dow Chemical Company, from Dupont-Dow Elastomers. ENGAGE ™ polyolefin elastomer. The most preferred comonomer content for thermoplastic applications such as film and injection molding is about 3 to 25 percent by weight. The preferred comonomer content for elastomer applications is from about 20 to about 40 weight percent. The most preferred terpolymer is the NORDEL IP ™ ethylene / propylene / diene polymer commercially available from DuPont-Dow Elastomers.

The melt index is measured according to ASTM D-1238, conditions 190 ° C / 2.16 kg (formerly known as Case E).

In a particularly preferred embodiment, the polymer is an ethylene / α-olefin / diene terpolymer. Suitable α-olefins are aolefins previously described as being suitable for making ethylene α-olefin copolymers. Suitable diomers as monomers for the preparation of such terpolymers are either

52382 conjugated or non-conjugated dienes are non-conjugated dienes having typically from 6 to 15 carbon atoms. Examples of suitable nonconjugated dienes which may be used to prepare the terpolymer are:

a) straight chain acyclic dienes such as 1,4-hexadiene, 1,5-heptadiene and 1,6-octadiene;

b) branched chain acyclic dienes such as 5-methyl-1,4-hexadiene, 3,7-dimethyl-1,6-octadiene and 3,7-dimethyl-1,7-octadiene;

c) single-ring alicyclic dienes such as 4-vinylcyclohexene, 1-allyl-4-isopropylidene cyclohexane, 3-allylcyclopentene, 4allylcyclohexene and 1-isopropenyl-4-butenylcyclohexane;

d) multi-closed chain alicyclic boiled and bridged closed z, fig dienes; disydopentadiene, alkenyl, alkylidene, cycloalkenyl and 5-methylene-2-norbomenon, 5-methylene-6-methyl-2-norbomenon, 5-methylene-6,6-dimethyl-2-norbomene, 5-propenyl-2-norbomene, 5 Cycloalkylidene norbomenes such as - (3-cyclopentenyl) -2-norbornene, 5-ethylidene-2-norbornene and 5-cyclohexylidene-2norbornene.

Preferred dienes are selected from the group consisting of 1,4-hexadiene, disildopentadiene, 5-ethylidene-2-norbomene, 5-methylene-2-norbomene, 7-methyl-1,6-octadiene, piperylene, 4-vinyloxyclohexene and the like.

Preferred terpolymers for the practice of the invention are ethylene, terpolymer of a diene (EPDM) which is not associated with propylene. Such terpolymers may be commercially available or available from companies such as DuPont Dow Elastomers LLC.

The total diene monomer content in the terpolymer is from about 0.1 to 15 weight percent, preferably from about 0.5 to 12 weight percent, and most preferably from about 1.0 to about 6.0 weight percent.

Both ethylene copolymers and ethylene terpolymers contain from about 20 to 90 weight percent ethylene, preferably from about 30 to 85 weight percent ethylene; the other comonomers make up the balance. Ethylene copolymers and terpolymers preferably have a weight average molecular weight (M) of at least about 10,000, more preferably at least about 15,000._wand up to about 1,000,000 or higher, preferably up to 500,000._wmay have.

52382

Ethylene homo- and copolymers used as starting materials of the invention, especially high density polyethylene (density greater than about 0.94 g / centimeter cube) are preferably manufactured using single point catalysts and preferably have a narrow molecular weight distribution (MWD), preferably about 3.5 '. Mw / Mn less than 2.5, more preferably less than 2.5, and most preferably less than 2.0.

The polioefins discussed earlier, particularly preferred species, and more preferably ethylene homopolymers and copolymers, are most preferably used in blends containing elastomers optionally at least one of the polyolefins (first polymer) and at least one polymer (second polymer) different from the first polymer. The second polymer is preferably any thermoplastic polymer selected from polyvinyl chloride, polypropylene, polyethylene terephthalate, polystyrene or other vinyl aromatic polymer and styrene block copolymers. Ethylene homopolymers and copolymers produced using single point catalysts may optionally be blended with polyolefin-carbon monoxide (CO) copolymers, such as ethylene-carbon monoxide copolymers, propylene-carbon monoxide copolymers, and ethylene-propylene-carbon monoxide copolymers. Polymers having carbon monoxide are within the skill in the art and are commercially available from The Dow Chemical Company and Shell Oil Company. Alternatively, U.S. Pat. 3,835,123; 3,984,388; 4,970,294; 5,554,777 and 5,565,547. Advantageous polymers for blends include, but are not limited to, different ethylene polymers or other natural or synthetic polymers. Advantageously different ethylene polymers are low (LDPE) (e.g., formed using high pressure, free-radical polymerization techniques), medium (MDPE) and high density polyethylenes (HDPE) (such as those made using Ziegler catalysts such as in US Patent No. 4,076,698). ethylene / ester copolymers, ethylene / vinyl acetate copolymers, ethylene and ethylene unsaturated carboxylic acid copolymers, homo and copolymers of alpha olefins. At least one of the polymer components in each blend used in the practice of the invention is formed using a single point catalyst.

When the polyolefins formed using the single point catalyst are used in the blends, the same monomer composition is used in amounts that will result in improved properties associated with its presence (described in detail hereinafter) when compared to the presence of a polymer having an average molecular weight number (Mn) and density. Preferably the polyolefins prepared using a single point catalyst are used as starting materials of the invention.

52382 at least about 5 weight percent, more preferably at least about 10 weight percent, most preferably at least about 20 weight percent of any blend. In a preferred embodiment, the blend comprises polyolefin made using 100 percent single point catalysts, preferably using metallocene catalysts. More specifically, elastomers made using single point catalysts to improve impact strength are preferably less than about 30 weight percent, and more preferably about 5 to 30 weight percent. The elastomer made using a single point catalyst in the blend of an HDPE and an elastomer is preferably present up to about 90 weight percent, more preferably from about 70 to 90 weight percent. The addition of HDPE facilitates the shaping of the mixture before the crosslinking (green state) is formed.

Preferred blends are: Blends (1): blend of two or more polyolefins made using a single point catalyst; Blends (2) comprise a blend of at least one polyolefin made using a single point catalyst and at least one polyolefin such as an ethylene polymer made using Ziegler Natta or a free radical catalyst or a combination thereof; Blends (3): a blend of at least one polyolefin made using a single point catalyst and at least one elastomer which is not described in blends (1) or (2); or Blends (4): at least one polyolefin and at least one thermoplastic polymer made using a single point catalyst. In each case, the polyolefin (s) made using single point catalysts are preferably ethylene polymers or copolymers.

Blends (1) and (2) contain polymer blends having different molecular weights but similar densities. These include the mechanical properties of the resulting crosslinked product, such as the low compression set (ASTM D-395 (60 ° C, 25 percent compression)) and the high tensile strength (ASTM D-412); mixture of poly (sulfonyl azide) and polymer (s) before crosslinking) I₂2.16 kg and 10 kg for I10.₂It is formed in order to compensate for the workability indicated by the / 10 ratio. A preferred embodiment in these blends is a blend of at least two HDPE polymers. A preferred alternative embodiment is a bi-mode molecular weight blend comprising at least one ethylene-alpha olefin elastomer, for example, used for wire cables, gaskets, profile extrusion and roofing. In another embodiment, the crosslinked polymers achieve balanced mechanical properties such as hardness measured by ASTM D2240-91 and stiffness measured by ASTM D-412-87.

52382 A blend with a two-mode density is formed. In this case, the blend is an HDPE blend containing less than about 30 weight percent elastomer to improve the stiffness when cross-linked to construction materials, tools and automotive parts. In another embodiment, a preferred blend comprises elastomer polymers blended with less than about 30 weight percent HDPE or LDPE to improve machinability to reduce adherence to the mold in the form shaping step in applications such as wire or cable jackets, gaskets, profile extrusion and roofing.

<img file="TR200000810T2_D0002.tif" />

Suitable elastomers in blends (3) are ethylene-vinyl acetate copolymer (EVA), copolymers of ethylene and ethylene-unsaturated carboxylic acid, styrene-butadiene block copolymers, natural rubber, isoprene rubber, and combinations thereof. Blends of single-point ethylene / alpha-ethylene elastomer with EVA are preferred embodiments for wire and cable jacket, gasket and profile extrusion.

Suitable thermoplastics in blends (4) are polyvinyl chloride, polypropylene, polyethylene terephthalate, polystyrene or other vinyl aromatic polymer, polioefin-carbon monoxide copolymers. The polyolefin prepared using the single point catalyst is preferably an elastomer. Preferably, the blend contains less than 30 weight percent elastomer to increase the stiffness of the thermoplastic component; the elastomer preferably has a viscosity sufficiently close to that of the thermoplastic component to obtain a homogeneous mixture and dispersion of the elastomer in the thermoplastic. Such blends are useful, for example, for construction materials, tools and automotive parts. In one embodiment, the thermoplastic blend component is preferably a polymer having tertiary carbon hydrogen bonds, such as a propylene polymer. The term propylene polymer is preferably used to refer to propylene homopolymers, copolymers and interpolymers having at least about 50 weight percent propylene. The practice of the invention is particularly useful with polymers having tertiary CH bonds because free radical-producing cross-linking agents such as peroxides generally produce shear at such tertiary points; therefore, by comparison, the practice of the invention results in less chain breaks than the use of peroxide or other free radical crosslinking agent.

Preferred olefin polymers for the production of foam structures of the invention are linear high density polyethylene (HDPE), linear low density polyethylene (LLDPE) made using single point catalyst 30. These olefin polymers include, for example, The Dow Chemical.

52382

Commercially available polyolefin plastomers from the Company under the trade name Affinity; Polymers commercially available under the tradename TAFMER ™ from Mitsui Petrochemical Industries; EXACT ™ polymers commercially available from Exxon Chemical Company; and polymers commercially available under the trade name ENGAGE ™ and Nordel IP EPDM from DuPont Dow Elastomers LLC.

Polymers previously described as suitable and preferred for use in the practice of the invention to form crosslinked polymers are also suitable and preferred for use in making crosslinked foams; however, the most preferred blend for making foams is a blend of at least one other elastomer such as EV elastomer, natural rubber, styrene-butadiene block copolymers, ethylene styrene interpolymers or a combination thereof, with an elastomer made using a single point catalyst.

I

In order to form a crosslink, the polymer is reacted with a polyfunctional compound capable of reacting with CH bonds. These polyfunctional compounds have at least two, preferably 2 functional groups capable of reacting with CH. Those skilled in the art recognize CH input reactions and functional groups capable of such reactions. For example, Mathur, NC; Snow, MS; Young, KM; and Pincock, JA Carbenes produced from diazo compounds as described in Tetrahedron (1985), 41 (8), pages 1509-1516; and Abramovitch, RA; Chellathurai, T.; Holcomb, WD; McMaster, IT; and Vanderpool, DP; J. Org. Chem. (1977), 42 (7), 2920-6 and Abramovitch, RA; Knaus, GN: J. Organ. Chem., (1975), 40 (7), 883-9.

Compounds having at least two functional groups capable of entering CH under the reaction conditions are referred to herein as crosslinking agents. Such crosslinking agents include alkyl and aryl azides (RN).₃), noble azides (RC (O) N₃), azidoformates (ROC (O) -N₃phosphoryl azides (RO)₂(PO) -N₃), phosphonic azides (R₂-P (O) -N₃) and silyl azides (R₃Si-N₃).

Polyfunctional compounds which can enter CH bonds include poly (sulfonyl) azides. Poly (sulfonyl azide) polyolefin reacted at least two sulfonyl azide groups (-SO₂N₃) any compound having the same composition. Preferably, the poly (sulfonyl azide) XRX is present. In this structure, each X SO₂N₃and R represents an unsubstituted or inert substituted hydrocarbyl, hydrocarbyl ether or silicon-containing group. This group preferably has sufficient carbon, oxygen or silicon atoms to separate the sulfonyl group to allow for an easy reaction between the polyolefin and the sulfonyl azide; between functional groups, preferably at least 1, 22

52382 more preferably at least 2 and most preferably at least 3 carbon, oxygen or silicon atoms. Although there is no critical limit to the length of R, each R has at least one carbon or silicon atom between the Xs and is preferably less than about 50, more preferably less than about 30, most preferably less than 20 carbon, oxygen or silicon atom. Within these limits it is much better for several reasons including thermal and shock stability. When R is a straight chain alkyl hydrocarbon, the sulfonyl azide groups preferably have less than 4 carbon atoms to reduce the tendency of the nitrite to bend and react with itself. Silicone containing groups include silanes and siloxanes, preferably siloxanes. refers to substitution with atoms or groups which do not interfere with the desired reaction or the desired properties of the resulting crosslinked polymers. These groups are fluorine, aliphatic or aromatic ether, siloxane and sulfonyl azide groups when more than two polyolefin chains are joined. Suitable structures are those wherein R is aryl, alkyl, aryl alkaryl, arylalkyl silane, siloxane or heterocyclic groups, and other groups which are inert and separate the sulfonyl azide groups as described. More preferably, R includes at least one aryl group, most preferably at least two aryl groups (for example, when R is 4,4'15 diphenylether or 4,4'-biphenyl) among the sulfonyl groups. When R is an aryl group, it is preferred that the group has more than one ring, as in the case of naphthalene bis (sulfonyl azide). Poly (sulfonyl azide) s are 1,5-pentane bis (sulfonyl azide), 1,8-octane bis (sulfonyl azide), 1,10-decane bis (sulfonyl azide), 1,10-octadecane bis (sulfonyl azide), 1-octyl-2,4,6-benzene tris (sulfonyl azide), 4,4'-bis (benzenesulfonyl azide), 1,6-bis (4'-sulfonazidophenyl (hexane), 2,7-naphthalene bis (sulfonyl) and mixed sulfonyl azides of chlorinated aliphatic hydrocarbons having from about 1 to 8 chlorine atoms of about 2 to 5 sulfonyl azide groups per molecule; and mixtures thereof. Preferred poly (sulfonyl azide) s are oxy-bis (4-sulfonylazidobenzene), 2,7naphthalene bis (sulfonyl azido), 4,4'-bis (sulfonyl azido) biphenyl, 4,4'-oxybis (benzenesulfonyl azide) and bis (4-sulfonyl azidophenyl) methane and mixtures thereof.

Sulfonyl azides are prepared by the reaction of sodium azide with the corresponding sulfonyl chloride, although oxidation of sulfonyl hydazines with various reagents (nitrus acid, diazot tetroxide, nitrosonium tetrafluoroborate) is used.

Polyfunctional compounds capable of entering CH bonds, carbene-forming compounds such as alkyl and aryl hydrazone and salts of diazo compounds, and alkyl and aryl azides (RN).₃), acyl azides (RC (O) N5), azidoformates (ROC (O) -N3), sulfonyl azides (R-SO2-N3), phosphoryl azides ((RO))₂- (PO) -N3), phosphonic azides (R₂-P (O) -N₃) and silyl azides (R3-S1-N3)

52382 forming compounds. Some of the crosslinking agents of the invention are preferred because of their tendency to form abundance in carbon-hydrogen input products. Hydrazone salts, diazo compounds, azidoformates, sulfonyl azides, phosphoryl azides and silyl azides are preferred because they form stable dual-state electron products (carbene and nitren) that carry out effective carbon-hydrogen entry reactions. Otherwise, 1) substantially reorganized by means of mechanisms such as Curtius type rearrangement, as in the case of 1) acyl azide and phosphonic azide, or 2) rapidly converted to triple-state electron form subject to hydrogen atom extraction reactions, as in the case of alkyl and aryl azides. It is also possible to choose from preferred crosslinking agents due to differences in temperatures at which various classes of crosslinking agents are converted to active carbene and nitren products. For example, those skilled in the art will appreciate that carbenes are effectively formed from diazo compounds at temperatures less than 100 ° C, whereas hydrazone salts, azidoformates and sulfonyl azide compounds react at temperatures above about 100 ° C at a suitable rate, up to about 200 ° C. (By appropriate speed is meant that the crosslinking agent reacts sufficiently slowly to provide suitable mixing and forming, so as to enable the commercial processing of the compositions, resulting in a final product in which the dispersion is substantially dispersed and placed in the desired position. and the dispersion may differ from product to product depending on the desired properties in the final product). Phosphoryl azides can be reacted at temperatures above about 180 ° C up to about 300 ° C, whereas silyl azides are preferably reacted at temperatures between about 250 ° C and 400 ° C.

For crosslinking in a polymer, the crosslinking agent is used in the amount of crosslinking, ie, in an effective amount to result in at least about 10 weight percent gelatin measured according to ASTM D-2765-procedure A. Preferably, at least about 30 percent gelatin, more preferably at least about 50 percent gelatin and most preferably about 90 percent gelatin are obtained in the practice of the invention. That is, the polymer is preferably converted from a thermoplastic to a thermoset polymer. Those skilled in the art recognize that the amount of poly (sulfonyl azide) sufficient to form crosslinking and at least about 10 weight percent gelatin will depend on the molecular weight of the azide used, the desired gelatin level, and the polymer properties, but this amount is poly (sulfonyl azide). Fame

52382 at a molecular weight of from about 200 to 2000, at least about 0.5 percent, preferably at least about 1 percent, more preferably at least about 1.5 percent, more preferably at least about 2 percent, based on the total weight of the polymer most preferably about 5 percent poly (sulfonyl azide). The amount of poly (sulfonyl azide), preferably less than about 15 percent, more preferably less than about 10 percent, by weight, of the total weight of the polymer to avoid bubbles generated by nitrogen released by the poly (sulfonyl azide) above this amount reacted with the polymer. preferably less than about 5 percent.

The poly (sulfonyl azide) is heated to at least the decomposition temperature of the sulfonyl azide in the presence of polymer to obtain crosslinking. As the decomposition temperature of poly (sulfonyl azide) is meant the temperature at which the azide is converted to the sulfonyl nitrite determined by differential scanning calorimetry (DSC) by eliminating nitrogen and heat in the process. Poly (sulfonyl azide) begins to react at a kinetically significant rate (suitable for use in the practice of the invention) at a temperature of about 130 ° C and reacts almost completely at DSC (scanning with 10 ° C / min) at about 160 ° C. ARC (screening with 2 ° C / h) indicates that the onset of fragmentation is about 100 ° C. The measure of the reaction is a function of time and temperature. The temperatures to be used in the practice of the invention are also determined by the softening or melting temperatures of the polymer starting materials. For this reason, the temperature is greater than about 90 ° C, preferably greater than 120 ° C, more preferably greater than 150 ° C, most preferably greater than 180 ° C.

The preferred time at the desired decomposition temperatures is sufficient time for reaction of the crosslinking agent with the polymer (s) to occur without undesired polymer matrix disintegration. The preferred reaction time in terms of the half-life of the cross-linking agent, ie the time required for approximately half of the agent to react at a preselected temperature, is the half-life of the cross-linking agent. This half life

It can be determined by DSC. For example, in the case of bis (sulfonyl azide), the reaction time is preferably at least about 4 minutes at 200 ° C. When producing a large polymer mass or a thick product, generally longer time is needed for the required heat to penetrate the polymer; this time is about 20 minutes.

The process of the invention preferably comprises the steps of: (a) mixing at least one polyolefin and at least one cross-linking fan in an amount of at least cross-linking reacting with this poholefin through the C30 H port; (b) shaping the resulting mixture; and (c) formed

52382 heating the shaped mixture to at least the decomposition temperature of the crosslinking agent such that a crosslinked polyolefin is formed.

The mixing of the polymer and the crosslinking agent is accomplished by any means known in the art.

The preferred processes of step (a) mixing the polyolefin crosslinking agent include at least one of the following: (a) blending the polymer dry with the crosslinking agent to form a substantially uniform mixture and melting the mixture into the processing equipment, for example the molten material mixer or forming device. to add; wherein the mixing occurs at a temperature lower than the decomposition temperature of the crosslinking agent; (b) a polymer comprising a crosslinking agent in liquid form and a crosslinking agent slurry in a liquid, for example dissolved in a solvent, polymer, preferably softened, melted or molten polymer, but alternatively in particulate form, solution or dispersed form polymer, preferably by melting inserting it into the operating equipment, for example by injection; (in the art, the polymer is said to generally absorb liquid); (c) at a temperature below the approximate decomposition temperature of the crosslinking agent, optionally blending in the molten state to form a first mixture of the first amount of the first polymer and the crosslinking agent, followed by a second polymer or a combination of the first mixture and a second polymer (e.g., a crosslinking agent concentrate mixed with at least one polymer and optionally other additives). mixed with the other additives to form a crosslink in the second polymer); (d) feeding at least one crosslinking agent, preferably in solid form, more preferably finely divided, eg in powder form, directly into, for example, a melt processing equipment, for example softened or melted polymer or combinations in an extruder, between processes (a) to (d) ( Processes b) and (c) are preferred, most preferred being (c). For example, process (c) is used to make a concentrate with the first polymer composition having a lower melting temperature at a temperature below the decomposition temperature of the crosslinking agent, and the concentrate is blended into a second polymer composition having a higher melting temperature. Concentrates are particularly preferred when the temperatures are high enough to result in loss of crosslinking agent by evaporation or decomposition which does not lead to reaction with the polymer, or under other conditions that will produce this effect. When the crosslinking agent is added in the dry state, the crosslinking agent may be crosslinked below the decomposition temperature.

52382 it is preferred to mix the softening or melted polymer with the coupling agent, followed by shaping the resulting mixture.

Thus, the steps of forming a mixture generally require at least two steps; the first step of mixing the polymer in particulate form, for example pellets, with the crosslinking agent and optionally other additives, followed by the melting step optionally and preferably containing additional mixing. Alternatively, the shaping step preferably comprises the step of melting the polymer mixture.

The term &amp; quot; melt processing &amp; quot; is used to refer to any process in which the polymer is softened or melted, such as extrusion, pelletizing, molding, thermoforming, film blowing, melt polymerization, fiber spinning and combinations thereof.

The polyolefin (s) and cross-linking agent are preferably formed in any manner which ultimately results in the desired reaction, preferably by mixing the polymer (s) with the crosslinking agent under conditions that allow sufficient mixing to avoid unequal amounts of localized reactions before forming. by exposing the mixture to sufficient heat for the reaction. Preferably, a substantially uniform mixture of the crosslinking agent and polymer is formed prior to exposure to the conditions under which the chain crosslinking occurs. A substantially uniform mixture is one in which the distribution of the crosslinking agent in the polymer is sufficiently homogeneous. This homogeneity must be demonstrated by a polymer that exhibits constant tensile and elongation properties in various samples and that no hardened samples have observable gelatin particles. This mixing is preferably achieved when the polymer is in the molten or molten state, ie above the crystalline melting temperature or in very well dispersed conditions rather than in the dissolved state or solid mass or granular form. The molten or molten form is more preferred to provide homogeneity rather than localized concentrations on the surface.

Any equipment, preferably equipment that provides adequate mixing and temperature control, may be used. The application of the invention is carried out in devices such as an extruder or a static polymer mixing device such as a Brabender mixer or Banbury mixer.

In the mixing step, optionally other additives within the skill of the art are mixed into the polymer. The crosslinked polymers of the invention optionally include powdered carbon, silica, titanium dioxide, color pigments, clay, zinc oxide, stearic acid, accelerators,

52382 hardening agents, sulfur, stabilizers, auxiliary agents, anti-disintegrating agents, processing aids, adhesives, tackifiers, plasticizers, waxes, early crosslinking inhibitors, discontinuous fibers (e.g., wood cellulose fibers) and expansion oils. These additives may optionally be added either before, during and after crosslinking formation of polyolefin elastomers (curing). The polyolefin elastomers are generally mixed with a filler, an oil and a curing agent at a high temperature (above room temperature, but preferably below the decomposition temperature of the crosslinking agent) to form themselves. The composition is material which is then cured at a temperature typically greater than that used during this process. Auxiliary agents such as triethyl cyanurate and trimethylpropane trimethacrylate are optionally used to improve cross-linking activity. The amount of adjuvant (based on polymer weight) is about 0.2 to 15 weight percent, preferably about 1 to 5 weight percent.

Preferably, powder carbon is added to the polyolefin elastomer prior to curing. Powder carbon is typically added to improve the tensile strength or stiffness of the composite product, but can also be used as an expanding agent or to conceal the color of the composite product. The powdered carbon is preferably present in an amount of 0 to 80 weight percent, more preferably 0.5 to 50 weight percent of the total weight of the formulation. When powder carbon is used to mask a color, it is typically used from 0.5 to 10 percent by weight of the formulation. When the powder is used to increase carbon stiffness and / or reduce the cost of the formulation, it is typically used in amounts greater than 10 percent by weight of the formulation.

Furthermore, one or more expansion oils will preferably be added to the polymer prior to cross-linking. Expansion oils are typically added to improve processability and low temperature flexibility and to reduce costs. Suitable expansion oils within the skill of the art are described, for example, in the Rubber World Blue Book 1975 Edition, Materials for Rubber and Composition Components, p. 145-190. Typical classes of expansion oils include aromatic, naphthenic and paraffinic expansion oils. Expansion oils are typically used in an amount of from 0 to 50 weight percent. When used, the expansion oil will typically be provided in an amount of at least 5 percent, more typically at least 15 to 25 percent of the total weight of the formulation.

52382

After mixing, the polymer will preferably be shaped before cross-linking is formed. Forming is within the skill in the art and includes processes such as coating of wires or cables, press molding, thermoforming and blow molding, fiber manufacturing, foaming, profile extrusion into shapes such as gaskets or automotive strips. There are many types of molding operations within the skill in the art which can be used to form fabricated products or parts from the formulations disclosed herein. These include various injection molding processes (eg, the Modem Plastic Encyclopedia / 89, mid-October 1988, Vol. 65, Issue 11, pp. 264-268, “Introduction to Injection Molding” and p. 270-27l (“Injection Molding of Thermoplastics”) and blow molding processes (eg Modem Plastic Encyclopedia / 89, mid-October 1988, Vol. 65, Issue 11, pp. 217-218, “Extrusion-Blow Molding”), profile extrusion, calendering and spraying.

Once shaped, the polymer is heated to at least the decomposition temperature of the crosslinking agent for a time sufficient to result in the desired crosslinking . Heating is carried out by means within the skill of the art such as water bath, sand bath or the like.

The process of the invention therefore comprises (a) forming a polymer mixture comprising at least one polyolefin prepared using a single point catalyst and at least one poly (sulfonyl azide) crosslinking agent in an amount sufficient to form at least crosslinking; (b) shaping the resulting mixture; and (c) heating the formed shaped mixture to a temperature of at least the decomposition temperature of the crosslinking agent. These steps optionally occur in any order resulting in a cross-linked product. The preferred embodiment is in alphabetical order, but in particular in the case of foam, the steps are optionally entirely or partially in another order or performed simultaneously. For example, optionally, a certain amount of heating to the decomposition temperature during or prior to shaping may be effected, for example, to increase the melt strength. In another embodiment, in the case of a foam in which a slice is formed before heating and the pressure is released after heating, the disintegration temperature may take shape or follow it before heating. Variations of all process steps resulting in a crosslinked polymer are within the scope of the invention.

52382

Application of the process of the invention for crosslinking of polymers results in crosslinked polymers, i.e. polymers having sulfonamide crosslinking between the various polymer chains. Cross-linked HDPE (density greater than 0.94 g / centimeter cube) made using a single point catalyst, preferably HDPE pipe having narrow molecular weight distribution, can be used in gasoline storage, chemical storage and agricultural storage. The resulting crosslinked polymers exhibit higher yield strength as measured by ASTM D-2290-77 and higher service temperature as measured by TMA (hereinafter described) relative to the starting material due to crosslinking of polymer chains. Products and fibers from HDPE made using single point catalyst after crosslinking both as contemplated herein, have higher rigidity measured than ASTM D-412 procedures compared to an HDPE made with a Ziegler Natta catalyst and treated according to the practice of the invention. having. Cross-linked HDPE can be used in fibers including woven or nonwoven fibers.

The medium density polyethylene copolymer film made using single point catalyst and crosslinked according to the practice of the invention can be used for wire-cable insulation, fiber, chemical depots, sheet making.

Products made from a single point catalyst, preferably made of cross-linked polyethylene copolymer having a narrow molecular weight distribution of at least one and preferably all components, made using Ziegler Natta catalyst, improved hardness compared to corresponding products made of a polymer crosslinked with poly (sulfonyl azide) or measured using ASTM D-412 compared to a corresponding product made of single point catalyst and crosslinked polyethylene copolymer using peroxide crosslinking agent. It has better elongation as measured by D-412 and better tensile strength as measured by ASTM D-412. A crosslinked polyolefin made using a single point catalyst and crosslinked according to the practice of the invention has better organoleptic properties, better oxidative stability (ASTM 573-88) and better than a corresponding polymer crosslinked using a peroxide as a crosslinking agent. It has the ability to adapt to weather conditions (ASTM D-2565).

The cross-linked polyolefin elastomers of the invention are used for wire and cable coating, roofing, floor coverings, gaskets, hoses, boots, automotive parts, automobile strips and elastomer.

52382 can be used in many applications, such as other parts known to require material. Roof covers, gaskets, boots and automobile strips made of the cross-linked elastomer of the invention have a better compression set as measured by ASTM D-395 compared to the corresponding product made using peroxide crosslinking agent as disclosed in the prior art (US Patent No. 5,580,920), it has better weatherability (ASTM 2565) and better oxidative stability (ASTM D573-88).

The cable insulation of the invention may be filled or unfilled. If filled, the amount of filler present should not exceed the amount that would lead to deterioration of the electrical and / or mechanical properties of the cross-linked elastomers. Typically, the amount of filler present is from 20 to 80 weight percent, preferably from 50 to 70 weight percent of the polymer. Exemplary fillers are kaolin clay, magnesium hydroxide, silica, calcium carbonate. In a preferred embodiment using the filler of the invention, the filler is coated with a material which prevents or retards any tendency to coincide with the curing reactions.

Other additives may be used in the preparation of the insulation of the invention and are included in this insulation and are anti-oxidants, process aids, pigments and lubricants.

The cable insulation of the invention may be applied in known amounts and by known methods (for example by the equipment and methods described in U. S. Patent Nos. 5,246,783 and 4,144,202). The cable insulation is prepared in a reactor-extruder equipped with a cable coating die, and when the insulation components are prepared, the insulation composition is extruded from the extruder onto the cable being pulled through the die.

The distinguishing features of this cable insulation are the tear strength measured by ASTM D-3756, the tensile strength measured by ASTM D-412, the compression strength measured by ASTM D-412, and the compression set measured by ASTM D-395.

In another embodiment of the invention, substantially linear ethylene polymers crosslinked according to the invention are formed as automotive strips. These strips are useful as insulation systems for doors, hoses, belt lines, hoods and similar products. The resulting materials are preferably clean and can be processed in conventional thermoplastic equipment. The automotive tapes of the invention exhibit greater weatherability than sulfur-hardened EPDM tapes.

52382

In another embodiment of the invention, crosslinked linear ethylene polymers are formed as fibers. When these fibers are heated to the crosslinking temperature (at least the decomposition temperature of the crosslinking agent), crosslinking occurs. These elastic fibers are manufactured in fabricated products such as woven or nonwoven fabric (eg washable garment), elastic spring (eg woven elastic belt), elastic filters for air / water filtration (eg non-woven air cleaners), and fiber floor coverings (eg non-woven carpet mats). available.

The crosslinked ethylene polymers of the invention, processes for making them, and intermediates for making them are used in the automotive field, such as fuel storage, in head applications (including gaskets and hoses), in industrial products such as tool parts (including frames), for example in pipes for building and construction applications. drainage pipes and electrical insulation (eg wire and cable coatings / insulation) and rubber products. Some of the fabricated products are automotive pipes, single-layer roofing and wire and cable voltage insulation and jackets.

One type of forming and crosslinking is foaming in which the polymer is shaped and crosslinked in the form of a foam. The crosslinking formation is optionally simultaneously with the foam formation, after the foam formation or a combination thereof. In the case of coupling, some crosslinking occurs during the foam formation and the additional crosslinking takes place later. All variations are referred to herein as cross-linking during foaming. Application of the process of forming the crosslink of the polymer during the foaming of the invention results in the cross-linked polymer foam, i.e., the polymer harvest having sulfonamide crosslinking between the various chains. Cross-linked polyolefins made using Ziegler Natta or free radical catalysts, preferably having a broad molecular weight distribution (MWD of 3.5 or greater), made of foams using a single point catalyst, preferably having a narrow MWD (less than 3.5, preferably greater foam cell size, lower homogeneous cell size distribution than the foams of the crosslinked corresponding polymer (MWD) of about 2.0 or less, exhibits lower tensile and compressive strength and lower rigidity. The term "cross-linking" is used to refer to foams having more than 10 percent gelatin determined by xylene removal.

Cross-linked polyolefinic foams, including foams of blends containing polyolefins, are used in a variety of applications where support is required under high or dynamic loading. This

52382 The foams are typically manufactured using a chemical blowing agent, such as azodicarbonamide, with the formation of crosslinking typically induced by peroxide degradation or electron beam radiation. When subjected to high temperature (greater than 130 ° C), the foaming agent is decomposed into a gas, eg nitrogen, and is simultaneously crosslinked to the polyolefinic matrix, for example by peroxide degradation. By achieving an optimum level of high temperature tensile properties through cross-linking, controlled decomposition of the degraded gas is allowed to produce foams with cells of the desired size. The foam crosslinking and foaming are optionally carried out either sequentially or simultaneously. Very small cell size foams, preferably about 100 [mu] m diameter, are produced by simultaneous crosslinking formation and decomposition of the blowing agent under pressure, for example at high temperature press or injection molding.

Those skilled in the art will recognize that prior art foaming processes using crosslinking formation through free radical producing agents can be adapted to poly (sulfonyl azide) and other interleaving crosslinking methods.

An embodiment of a process for producing the crosslinked ethylene polymer foam structure according to the invention is as follows: First, the foamable melt polymer material is formed by blending and heating the ethylene polymer material with a degradable chemical foaming agent. Secondly, crosslinking is induced in the foamable melt polymer material. Third, the foamable molten polymer material is expanded by subjecting it to high temperature to form the foam structure.

The resulting foam structure is in any physical form known in the art, such as sheet, billet, injection molded product or donut form. Other useful forms are expandable or foamable particles, moldable foam particles or beads, and products formed by expansion and / or association and boiling of these particles.

Processes for manufacturing ethylene polymer foam structures and excellent information on their processing CP Park, “Polyolefin Foam”, Chapter 9, Manual of Polymer Foams and Technology, D. Klempner and KC Frisch edition, Hanser Publishers, Munich, Vienna, New York, Barcelona (1991).

52382

This foam structure blends and heats the polymer material comprising at least one substantially random polymer and a degradable chemical foaming agent to form a foamable plasticized or melted polymer material, extruding the foamable molten polymer material from a mold, The polymer may be prepared by cross-linking the molten polymer material and subjecting the molten polymer material to a high temperature leading to the release of the blowing agent to form the foam structure. The polymer material and the chemical blowing agent may be mixed and melt-blended by any means known in the art, such as an extruder, a mixer or blender. The chemical blowing agent is preferably dry blended with the polymer material before being heated to form the molten form, but may also be added when the polymer material is in the molten phase. The crosslinking may be induced by the addition of poly (sulfonyl azide) crosslinking agent. The induction of the crosslinking and exposure to a high temperature to create foaming or swelling can occur simultaneously or sequentially. The crosslinking agent may be incorporated into the polymer material in the same manner as the chemical blowing agent.

Further, the foamable molten polymer material is preferably heated or subjected to a temperature of less than 150 ° C to prevent disintegration of the crosslinking agent or foaming agent and to prevent premature crosslinking formation. The foamable molten polymer material is extruded or extruded from a die of the desired shape to form a foamable structure. The foamable structure is then crosslinked and swollen to form a foam structure at an elevated or elevated temperature (typically 150 ° C-250 ° C), such as inside a furnace. This structure can be manufactured in the form of sheet or thin plank according to the above process.

This foam structure is described in British Pat. The long-field die can also be manufactured as a continuous plank structure by an extrusion process as described in US Pat. No. 2,145,961A.

In this process, the polymer, the degradable blowing agent and the crosslinking agent are mixed in an extruder; the mixture is heated to form crosslinking of the polymer in a long-field mold and to break up the foaming agent; and the foam structure and the mold contact face are lubricated with a suitable lubricant, while the foam structure is shaped as it passes through the die.

The foam structure may also be formed as cross-linked foam beads suitable for molding into various products. Separate resin particles, such as granular resin pellets, to form foam beads may be a liquid in which they are substantially insoluble, such as water.

52382 suspended in the medium; impregnating the crosslinking agent and foaming agent at high pressure and temperature in an autoclave or other pressure vessel; and rapidly discharged to atmosphere pressure medium or low pressure location to swell to form foam beads. In one version, the polymer beads are impregnated with the blowing agent, cooled, discharged from the container and then inflated with heating or steam. In a derivative of the above process, the styrene monomer is impregnated to the suspended pellets, optionally together with the crosslinking agent, to form an interpolymer associated with the ethylene polymer material. The blowing agent may optionally be impregnated in the resin pellets, either in suspension or alternatively in the anhydrous state. The swellable beads then swell by steam heating and are molded by conventional molding for swellable polystyrene foam beads.

The foam beads may be molded by any means known in the art, for example by heating the beads by steam to fill the foam beads into the mold, press the mold to press the beads and perform the joining and boiling of the beads to form the product. Optionally, the beads may be preheated with air or other blowing agent before being filled into the mold. Excellent teaching of the above processes and molding methods is described in CP Park, supra, p. 227-233, U.S. Pat. US 3,886,100. U.S. Patent No. 5,141,662; US Patent No. 3,959,189; 4,168,353 and U.S. Pat. U.S. Patent No. 5,141,662; No. 4,429,059. The foam beads may also be prepared by preparing a mixture of polymer, crosslinking agent and degradable mixtures in a suitable mixing device or extruder, and forming the mixture into pellets and heating the pellets to crosslink and swell.

The resulting foam structure can optionally be manufactured in the form of a donut. Said foam structure is formed by mixing the polyolefin polymer material, a crosslinking agent and a chemical blowing agent to form a sheet, heating the mixture in a mold and blowing the pressure in the mold to release the crosslinking agent to crosslink the polymer material and to decompose the blowing agent in the mold. can be manufactured in the form. Optionally, the donut form formed by depressurization may be reheated to produce further swelling.

The crosslinked polymer sheet is manufactured by heating the polymer sheet containing the chemical crosslinking agent. The crosslinked polymer sheet is cut into the desired shapes and is applied to the polymer at the softening point to result in the preselected foam density.

52382 above the temperature and sufficient level N₂ N under sufficient pressure to absorb₂ It is adsorbed; relieving the pressure causes the bubbles to nucleate and a certain swelling of the plate. The plate is reheated in a low pressure vessel at a pressure above the softening point, and then re-pressurized to swell the foam.

The blowing agents useful in manufacturing the resulting foam structure are degradable chemical blowing agents. These chemical blowing agents decompose at elevated temperatures to form gas or vapor to blow the polymer into foam form. The agent is preferably in solid form because it can easily be ground dry together with the polymer material. Chemical blowing agents, azodicarbonamide, azodiisobutiro-nitrile, barium azodicarboxylate, N, N'-dimethylN, N'-dinitrosoterephthalamide, Ν, Ν'-dinitrosopentamethylenetetramine, benzenesulfon hydrazide, 4,4oxybenzene sulfonyl semicarbazide and p-toluene sulfonyl preferable. Additional information on chemical blowing agents CP Park, supra, p. 205208 and FA Shutov, “Polyolefin Foam”, Polymer Foams and Technology Handbook, p. 382402, D. Klempner and KC Frisch, Hanser Publishers, Munich, Vienna, New York, Barcelona (199 l).

The chemical blowing agent is blended with the polymer material in an amount sufficient to form 0.2 to 5.0, preferably 0.5 to 3.0, and more preferably 1.0 to 2.50 moles of gas or vapor per kilogram of polymer.

In some processes, a physical blowing agent may be used to fabricate this structure. Physical blowing agents include organic and inorganic agents. Suitable inorganic blowing agents are carbon dioxide, nitrogen, argon, water, air, nitrogen and helium. Organic blowing agents are aliphatic hydrocarbons having from 1 to 9 carbon atoms, aliphatic alcohols having from 1 to 3 carbon atoms, and aliphatic hydrocarbons having from 1 to 4 carbon atoms partially and fully halogenated. Aliphatic hydrocarbons are methane, ethane, propane, n-butane, isobutane, npentane, isopentane and neopentane. Aliphatic alcohols are methanol, ethanol, n-propanol and isopropanol. Aliphatic hydrocarbons partially and fully halogenated are fluorocarbons, chlorocarbons and chlorofluorocarbons. Examples of fluorocarbon include methyl fluoride, perfluoromethane, ethyl fluoride, 1,1-difluoroethane (HFC-152a), 1,1,1-trifluoroethane (HFC143a), 1,1,1,2-tetrafluoroethane (HFC-134a), pentafluoroethane, difluoromethane, perfluoroethane, 2,2difluoropropane, 1,1,1-trifluoropropane, perfluoropropane, dichloropropane, difluoropropane, perfluorobutane, perfluorocyclobutane. Partial halogen which may be used in the present invention

52382 combined chlorocarbons and chlorofluorocarbons methyl chloride, methylene chloride, ethyl chloride, 1,1,1-trichloroethane, 1,1-dichloro-1-fluoroethane (HFC-141b), 1-chloro-1,1-difluoroethane (HCFC142b), chlorodifluoromethane (HCFC-22), 1,1-dichloro-2,2,2-trifluoroethane (HCFC-123) and 1-chloro-1,2,2,2-tetrafluoroethane (HCFC-124). Fully halogenated chlorofluorocarbons are trichloromonofluoroethane (CFC-11), dichlorodifluoromethane (CFC-12), trichlorotrifluoroethane (CFC-113), 1,1,1-trifluoroethane, pentafluoroethane, dichlorotetrafluoroethane (CFC-114), chloroheptafluoropropane and dichlorohexafluoropropane.

The amount of blowing agent included in the molten polymer material to make a foam-forming polymer gelatin is 0.2 to 50, preferably 0.5 to 3.0, and more preferably 1.0 to 2.50 moles per kilogram of polymer.

The resulting foam structure has a crosslinked density of 5 to 90 percent, preferably 30 to 80 percent, according to Method A of ASTM D-2765-84.

The resulting foam structure has a density of less than 500, preferably less than 250, and more preferably about 10 to 150 kilograms / cubic meter. The average cell size of the foam is about 0.05 to 5.0 millimeters, preferably about 0.1 to 2.0 millimeters, and more preferably about 0.2 to 1.0 millimeters, according to ASTM D-3576.

The foam structure formed is optionally closed cell or open cell according to ASTM D-2856-A.

Other components which may optionally be added to the foam mixture include fillers such as calcium carbonate, talc, clay, magnesium carbonate and mica; transition metal salts (particularly lead, cadmium and zinc salts), polyol, urea, alcohol amine and foaming agent activators, including organic acid. Zinc oxide and zinc stearate are preferred. Pigments are powder carbon, titanium dioxide, cadmium based or other inorganic or organic based pigments. The foam nucleators are talc, silicon dioxide, titanium dioxide and clay.

Anti-oxidants can be, for example, phenolic, phosphitic, and the like. can also be included to extend the shell life of the final product. Process aids such as low molecular weight polyethylene waxes, ester waxes, paraffin wax, paraffin oil, mineral oil, naphtha oil, bisteramide, stearamide, calcium stearate and stearic acid may also be used. Other additives include, for example, ultraviolet absorbers, flame retardants and the like. can also be added to the polymer mixture.

52382

Foams prepared from crosslinked ethylene copolymers according to the practice of the invention exhibit higher tensile strength, stiffness and tear resistance than foams prepared from the same starting material polymers crosslinked with free radical producing crosslinking agents.

The foams are converted into final products by processes such as press molding, injection molding, extrusion, vertical and horizontal furnace expansion and furnace hardening and combinations thereof. When used in combination, the processes are optionally used simultaneously or sequentially, as is known in the art.

There are many types of molding operations within the skill in the art which can be used to form fabricated products or parts from the formulations disclosed herein. These include various injection molding processes (for example, the Modem Plastic Encyclopedia / 89, mid-October 1988, Vol. 65, Issue 11, pp. 264-268, Giriş Introduction to Injection Molding ”and p. 270-271 (Enj Injection Molding of Thermoplastics ”) and blow molding processes (eg Modem Plastic Encyclopedia / 89, mid-October 1988, Vol. 65, Issue 11, pp. 217-218,“ Extrusion-Blow Molding ”), profile extrusion, calendering and spraying.

The following examples are intended to illustrate and not limit the invention. Unless otherwise indicated, the proportions, parts and percentages are by weight. While the examples of the invention (eg) are expressed numerically, the comparison samples (MN) are expressed alphabetically and are not examples of the invention.

Test Methods:

The xylene separation was carried out by weighing 1 gram of polymer samples. Samples are then transferred to the well basket to be placed in boiling xylene for 12 hours. After 12 hours the sample baskets are removed and placed in a vacuum oven at 150 ° C and 28 inch Hg vacuum for 12 hours. After 12 hours, samples are taken, cooled to room temperature within 1 hour, and then weighed. The results are reported as the percentage of polymer separated. The percentage of polymer separated is calculated according to ASTM D-2765, Procedure “A, as follows: Percent of polymer separated = ((starting weight-ending weight) / starting weight.

52382

Samples were prepared either using a HaakeBuchler Rheomix 600 mixer with roller-style blades connected to a HaakeBuchler Rheocord 9000 Torque rheometer, or using a Brabender mixer (Type REE No. A-19 / SB) with a 50 g 2 h mix container.

A Perkin-Elmer model TMA 7 thermo-mechanical analyzer (TMA) was used to determine the upper service temperature (UST). 102 g sensing tip force and 5 ° C / min heating rate were used. The test sample was a disc about 2 mm in diameter, prepared by pressing the disc in molten state at 190 ° C and air cooling to room temperature. The UST sensor tip was taken after 1 mm penetration into the sample.

Elongation, fracture unit stress and stiffness were determined by processing the 1/16 inch plates in the press die. The tensile samples were then cut from these plates and tested in an Instron Tensile Tester by drawing at 5 inches / minute according to ASTM D-1708. This procedure was used in the examples of the invention because it conforms to smaller sample sizes. ASTM 412 is also useful for evaluating the tensile properties of larger samples. The results are thought to be comparable, but are not comparable in the main rare cases, the values ​​obtained by the ASTM 412 procedure being preferred in evaluating the products of the invention.

All instruments were used according to the manufacturer's instructions.

The samples were prepared using a HaakeBuchler Rheomix 600 mixer having cylinder-style blades available from Haake Inc. connected to a commercially available rheometer from Haake Inc. under the trademark HaakeBuchler Rheocord 9000 Torque rheometer. The following materials were used:

Dicumyl Peroxide: The material available from Hercules Corporation and sold under the trade name DI-CUP R under the batch number 43 HR-233 peroxide was used as received.

4,4'-oxybis (benzenesulfonyl azide # CAS (7456-68-0)). This bis (sulfonyl azide) was prepared by reacting the commercially available corresponding bis (sulfonyl chloride) with sodium azide. The aqueous sodium azide bis (sulfonyl chloride) was added to the acetone solution and the product was separated by precipitation with excess water.

Example 1-3

52382

ENGAGE D-8190 from DuPont Dow Elastomers LLC (0.858 g / cm)³, 0.5 MI, 2.0 MWD) 40.0 g of ethylene / octene copolymer available under the trade name Haake Inc. under the trade name HaakeBuchler Rheocord 9000 Torque rheometer equipped with a Haake 600 mixing vessel having cylinder-style blades. to a commercially available rheometer. The mixing vessel temperature was 120 ° C and the sample was stirred at 75 rpm. After the polymer was melted, 0.40 g (1.1 weight percent, 1.05 mmol) of 4,4'-oxybis (benzenesulfonyl azide # CAS (7456-68-0)) was added to the mixing vessel and the working hour started. The sample was stirred for 8 minutes. The polymer was removed and processed at 120 ° C in a press die for 20 minutes at a force of 20,000 lbs. After 3 minutes the sample was taken and held in a press at 190 ° C for 10 minutes. During this time, the sulfonyl azide reacts to form a cross-linking of the polymer. The sample was taken from the press and allowed to cool.

The procedure of Example 1 was repeated in Example 2 using 0.6 g (1.5 weight percent, 1.5 mmol) of 4,4'-oxybis (benzenesulfonyl azide # CAS (7456-68-0)).

The procedure of Example 1 was repeated in Example 3 using 0.8 g (2.0 weight percent, 2.1 mmol) of 4,4'-oxybis (benzenesulfonyl azide # CAS (7456-68-0)). Tensile properties and TMA performance of the samples were measured and the results are given in Table 1.

Comparative Samples AC

ENGAGE D-8190 from DuPont Dow Elastomers LLC (0.858 g / cm)³40.0 g of ethylene / octene copolymer available under the trade name Haake Inc. under the trademark HaakeBuchler Rheocord 9000 Torque rheometer equipped with a Haake 600 mixing vessel having cylinder-style blades. to a commercially available rheometer. The mixing vessel temperature was 120 ° C and the sample was stirred at 75 rpm. After melting the polymer, 0.28 g (0.7 weight percent, 1.05 mmol) of dicumyl peroxide was added to the mixing vessel. The sample was stirred for 5 minutes. The polymer was removed and processed at 120 [deg.] C. in a press die for 20 minutes at a force of 20,000 lbs. After 3 minutes the sample was taken and held in a press at 180 ° C for 10 minutes. During this time, the sulfonyl azide reacts to form a cross-linking of the polymer. The sample was taken from the press and allowed to cool.

I

52382

The procedure of Comparative Sample was repeated using 0.4 g (1.0 weight percent, 1.5 mmol) of dicumyl peroxide in Comparative Sample B.

The procedure of Comparative Sample A was repeated using 0.56 g (1.4 weight percent, 2.1 mmol) of dicumyl peroxide in Comparative Sample C. Tensile properties and TMA performance of the samples were measured and the results are given in Table 1.

Comparative Sample D

Comparative Sample D, ENGAGE D-8190 from DuPont Dow Elastomers LLC (0.858 g / cm 2)³Is a sample of the same ethylene / octene copolymer available under the trade name 0.5 MI, 2.0 MWD), but no crosslinking has been formed according to the practice of the invention. The sample was processed in the press mold to make test samples without mixing.

Table 1-Comparison of Mechanical Properties of Cross-Linked Polymers with Azide and Peroxide

<td>Sample</td><td>Cross connection agent (Mmol)</td><td>TMA (° C)</td><td>Peak Unit Stress (Psi) **</td><td>SI Unit denominated Peak Unit Stress</td><td>Percent Elongation ****</td><td>SI Unit denominated Stiffness*** (Cmkg / cm³)</td><td>Rigidity (inlh / in.cube)</td>

<td>Example 1</td><td>Azure (1.05)</td><td> &gt; 190</td><td> 1650</td><td> 11,38</td><td> 850</td><td> 504</td><td> 7200</td>

<td>Example 2</td><td>Azure (1,5)</td><td> &gt; 190</td><td> 1380</td><td> 9,51</td><td> 820</td><td> 412</td><td> 5880</td>

<td>Example 3</td><td>Azure (2,1)</td><td> &gt; 190</td><td> 1100</td><td> 7,58</td><td> 570</td><td> 266</td><td> 3800</td>

<td>Comparison Num. the *</td><td>Peroxide (1.05)</td><td> 95</td><td> 1200</td><td> 8,27</td><td> 930</td><td> 413</td><td> 5900</td>

<td>Comparison Num. B *</td><td>Peroxide (1,5)</td><td> 150</td><td> 1100</td><td> 7,58</td><td> 830</td><td> 347</td><td> 4950</td>

<td>Comparison Num. C *</td><td>Peroxide (2,1)</td><td> 180</td><td> 730</td><td> 5,03</td><td> 580</td><td> 189</td><td> 2700</td>

<td>Comparison Num. D*</td><td> 0</td><td> 56</td><td> 910</td><td> 6,27</td><td> 950</td><td> 347</td><td> 4950</td>

52382 * Not an example of the invention *** Stiffness was measured by ASTM D-1708 procedure.

** Peak voltage was measured by ASTM D-1708 procedure.

**** Total Elongation was measured by ASTM D-1708.

The data in Table 1 indicate that the bifunctional sulfonyl azide at a given molar concentration of the cross-linking agent provides improved stiffness and improved temperature resistance as measured by TMA compared to peroxide cross-linked samples.

Procedure for Examples 4, 5 and 6:

Example 4 Nordel IP NDR 3720 hydrocarbon rubber from DuPont Dow Elastomers LLC (0.88 g / cm 2)³Haake Rheoordord System equipped with a Haake 3000 mixing vessel having a sample cylinder style blades of 200 g of ethylene / propylene / diene terpolymer obtainable under the trademark Mooney viscosity 20, 2.0 MWD (measured by ASTM D 1646-92). 9000 Torque was added to a rheometer commercially available from Haake Inc. under the trademark rheometer. Ethylene-propylene-diene terpolymer has been reported to be made using a single point catalyst. The mixing vessel temperature was 120 ° C and after addition of the sample poly (sulfonyl azide), it was stirred for 3 minutes at 20 rpm, then the stirring cycle was increased to 40 rpm and stirred for 6 minutes. After melting the polymer, 1.0 g (1 weight percent) of 4,4-disulfonyazidophenyl ether was added to the mixing vessel and the working hour started. The sample was stirred for 8 minutes. The polymer was removed and processed at 130 [deg.] C. in a press die for 3 minutes at a force of 20,000 lb (88964 Newton). After 3 minutes, the sample was taken and held under a pressure of 300 lb (1334 Newton) in a press at 190 ° C for 15 minutes. During this time, the sulfonyl azide reacts to form a cross-linking of the polymer. The sample was taken from a press of 190 ° C and held for 6 minutes in a press at 32 ° C with a force of 300.00 lb (1334 Newton).

In Example 5, the procedure of Example 4 was obtained from Mitsui Petrochemical Industries under the trade name Tafiner PO0480 (Mw / Mn = 2.02, Mw-122.00, melt index - 1.1 g / 10 min and density 0). Was repeated using 200.00 g of ethylene / propylene copolymer (87 g / centi cubic meter). Tafiner P0480 polymer has been reported to be manufactured using a single point catalyst.

52382

The procedure of Example 4 in Example 6 is an ethylene-octene copolymer commercially available under the trade name ENGAGE 8100 polyolefin elastomer from DuPont Dow Elastomers LLC (melt index = 1.0 g / 10 min and density 0.87 g / centimeter cubic). was repeated. It has been reported that the polyolefin elastomer is manufactured using a single point catalyst.

Procedure for Comparative Sample E:

A 40 g sample of ethylene / propylene copolymer commercially available under the trade name Vistalon 707 (0.872 g / cubic centimeter, 0.5 MI g / 10 minutes) from Exxon Chemical Company for Comparative Sample E, was prepared using a Haake 600 having cylinder-style blades. Haake Rheocord System 9000 Torque rheometer equipped with a mixing vessel was added to a rheometer commercially available from Haake Inc. under the trade name. The mixing vessel temperature was 120 ° C and the sample was stirred at 20 rpm. After melting the polymer, 1.6 g (4 weight percent) of dicumyl peroxide was added to the mixing vessel. The sample was stirred for 5 minutes. The polymer was removed and processed in a press die at 138 ° C with a force of 20,000 lb for 1 minute. Plates of 15.2 cm x 15.2 cm x 1.27 mm (6 inch x 6 inch x 50 mil) were removed from the mold and then immediately cooled to room temperature on water-cooled plates. These plates were cut into four 7.6 cm x 7.6 cm x 1.27 mm (3 inch x 3 inch x 50 mil) plates. These small plates were processed in a die press at 138 [deg.] C. for 12 minutes with a force of 12,000 lb (53378 Newton) for 15 minutes from the mold 15.2 cm x 15.2 cm x

Plates of 0.51 mm (6 inch x 6 inch x 20 mil) were removed and then cooled as described above. The second molding step was performed to eliminate air bubbles. Plates of 15.2 cm x 15.2 cm x 0.51 mm (6 inch x 6 inch x 20 mil) were cured in a press at 182 ° C for 10 minutes. The tensile properties of the samples were measured.

Table 2- Measured Properties for Example 4-6 and Comparative Sample E

<td>Sample</td><td>Rosin</td><td>TOP (° C)</td><td>Peak Unit Stress (PSI)</td><td>Peak Unit Stress (MPa)</td><td>Elongation (percent)</td><td>Stiffness (Inçlb / inch³)</td><td>Stiffness (Cmkg / cm³)</td>

<td>Example 4</td><td>Tafmer 0480 Polymer</td><td> &gt; 190</td><td> 978</td><td> 6,74</td><td> 978</td><td> 6180</td><td> 433</td>

52382

<td>Example 5</td><td>Nordel IP 3720 Polymer</td><td> &gt;190</td><td> 1510</td><td> 10,48</td><td> 1016</td><td> 6660</td><td> 466</td>

<td>Example 6</td><td>Engage 8100 polyolefin elastomer</td><td> &gt; 190</td><td> 1889</td><td> 13,02</td><td> 794</td><td> 6948</td><td> 486</td>

<td>MN E</td><td>Vistalon 707 Polymer</td><td>N / M *</td><td> 690</td><td> 4,75</td><td> 630</td><td> 2700</td><td> 189</td>

* N / M- not measured

The results in Table 3 indicate that a number of elastomers prepared using a single point catalyst can be crosslinked using poly (sulfonyl azide). The stiffness of the polymer made using the crosslinked single point catalyst according to the practice of the invention was higher than the corresponding polymer (similar density and melt index) (BC E) polymerized with Ziegler Natta using peroxide as the curing agent.

Example 7 and Comparative Sample F:

Mixing Procedure of Reactors:

In Example 7, an ethylene-octene copolymer commercially available under the trade name ENGAGE 8100 polyolefin elastomer from DuPont Dow Elastomers LLC (melt index = 1.0 g / 10 min and density 0.87 g / cubic centimeter) is disclosed in Uniroyal Chemical Company. commercially available azodicarbonamide blowing agent under the tradename Celogen AZ 130 blowing agent, and zinc oxide blowing agent activator commercially available from CP Hall Chemical Inc.. Engage 8100 polyolefin elastomer, Celogen AZ 130 blowing agent and zinc oxide are weighed and mixed for 3 minutes at 100-120 C in a commercially available mixer under the trade name Banbary BR under the trade name Banbary BR. 4,4'oxibis (benzenesulfonyl azide) CAS # (7456-68-0) was added and stirred for an additional 3 minutes. The mixture was then sheeted in an inch-thick (0.63 cm) cylinder heated to 80 ° C.

The method of Example 7 was repeated in Comparative Example F, but instead of poly (sulfonyl azide), 20.2 g of dicumyl peroxide on 40 percent active clay commercially available under the trade name DiCup 40 KE from Hercules Corporation were used.

52382

Table 3- Foam formulation

<td>Reagent</td><td>Reaction component for Example 7 weight</td><td>For Comparative Example F reaction component weight</td>

<td>Engage 8100 polyolefin elastomer</td><td> 1063,9</td><td> 1063,9</td>

<td>Celogen AZ 130 foaming agent</td><td> 42,6</td><td> 42,6</td>

<td>Zinc Oxide</td><td> 10,6</td><td> 10,6</td>

<td>DiCup 40 KE peroxide</td><td> 0</td><td> 20,2</td>

<td>4,4'-oxybis (benzenesulphonyl azide)</td><td> 10,6</td><td> 0</td>

Procedure for Making Foam from Example 7:

The plate passing through the cylinder was cut into cubic pieces of approximately 0.25 x 0.25 x 0.25 inches (0.635 x 0.635 x 0.635 cm). Approximately 12 g of these cut pieces were weighed and placed in a frame (die frame) with a diameter of 1 inch (2.54 cm) and a hole of% inch (0.635 cm). The mold frame was then held for 20 minutes in a pan press with a force of 25,000 pounds (111.205 Newton) at 120 ° C. The plate was then foamed for 7 minutes by applying a force of 50,000 pounds (222,410 Newtons) at 180 ° C. The press was opened and the foam spread.

Procedure for Making the Foam of Comparative Sample F:

The procedure of Example 7 was repeated using the plate of Comparative Sample F and the foaming temperature was 160 ° C / 9 minutes instead of 180 ° C / 7 minutes.

The foam density was measured at 20 ° C using isopropanol as the liquid medium according to ASTM D 792-86. The foam cell size was determined using an electron scanning microscope.

Table 4- Example 7 and Properties of Foams of Comparative Sample F

<td>Sample</td><td>Foam Density (Kg / ft³)</td><td>Foam Density (Kg / m³)</td><td>Cell size (mm)</td>

<td>Example 7</td><td> 8,39</td><td>¹³⁶</td><td> 0,175</td>

<td>Comparison Num. F</td><td> 9,96</td><td> 161</td><td> 0,375</td>

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Example 7 using poly (sulfonyl azide) at low density (8.39 lb / ft)³) (136 kg / m)³) and a small cell size (0.175 mm diameter) good quality foam was obtained. The foam was very flexible, rigid and elastic (based on manual compaction, bending and drawing of the sample).

The data in Table 4 indicate that the foam made from elastomer prepared using the single point catalyst and poly (sulfonyl azide) crosslinking agent according to the embodiment of the invention has a much smaller cell size than the foam of the cross-linked Comparative Sample F using peroxide. The smaller cell size foam of Example 7, the lower stiffness measured according to the procedures of ASTM D 224010 91 relative to the large cell size foam of Comparative Sample F, the higher tear strength measured according to ASTM D-3574 (Test F), ASTM High tensile strength and elongation measured according to the procedures of D-1708, and more desirable foam properties such as the low pressure set measured according to the procedures of ASTM D-395 (50 ° C, 50 percent compression, 6 hours). The foam of Comparative Sample F also has an undesirable odor which is thought to be caused by the degradation products of the peroxide. In contrast, the foam of Example 7 exhibited particularly desirable odorless properties in applications such as shoe foam, construction foam and in-vehicle equipment foam.

Example 8 and Comparative Sample G:

The procedure of Example 7 was repeated for Example 8, but a large sample strip (185 g) and a 6 x 6 x 0.5 inch (0.15 x 0.15 x 0.013 m) perforated frame were used.

The procedure of Comparative Sample F was repeated for Comparative Sample G, but a large sample strip (185 g) and a 6 x 6 x 0.5 inch (0.15 x 0.15 x 0.013 m) perforated frame were used.

The properties of the foams of Example 8 and Comparative Sample G were measured and given in Table 5.

Table 5- Example 8 and Properties of Foams of Comparative Sample G

<td>Foam Properties</td><td>Example 8</td><td>Example 8</td><td>Comparison Sample G</td><td>Comparison Sample G</td>

<td>Density ASTM D 792-86</td><td>7.1 lb / ft³</td><td>114 kg / m³</td><td>8.29 lb / ft³</td><td>133 kg / m³</td>

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<td>Soldier C Hardness ASTMD2240-91</td><td> 25</td><td></td><td> 30</td><td></td>

<td>Elasticity ASTM D 3574-86 (Test H)</td><td>67 percent</td><td></td><td>59 percent</td><td></td>

<td>Ultimate Strength ASTMD1708</td><td>217 psi</td><td>1,496 MPa</td><td>215 psi</td><td>1,482 MPa</td>

<td>Fracture Elongation ASTM D 1708</td><td>732 percent</td><td></td><td>670 percent</td><td></td>

<td>ASTM D for rigidity 1708</td><td>425 inch-lb / inch cube</td><td>29.7 cm-kg / cm³</td><td>383 inchlb / inch. Cube</td><td>26.8 cm-kg / cm³</td>

The data in Table 5 shows that the foam made of elastomer prepared using a single point catalyst and poly (sulfonyl azide) crosslinking agent according to the practice of the invention has a lower hardness (more flexibility), lower density, higher rigidity than comparative Sample G made using peroxide. and has higher elasticity.

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