An article molded from ethylene hydrocarbon copolymer

@ Start of patent duration: 1981 11 15 Longest possible duration:

© Issued on: 1982 07 12 © inventor:

© dependence:

© Pamphlets considered to delineate the prior art:

Nr.367443

The invention relates to the use of ethylene-hydrocarbon copolymers for the production of articles by injection molding, rotational molding and the blow molding process.

There is currently a need for molded plastic articles such as gaskets, closures, food and waste containers, bottles, dishes and toys that are to be stress crack resistant when in contact with detergents, vegetable oils and fats, and / or the hot low temperatures (ie below 0 ° C) have good impact resistance. Attempts have been made to produce such articles from high pressure ethylene homopolymers or from blends of high density polyethylene with copolymers of ethylene and polar comonomers such as vinyl acetate or ethyl acrylate.

However, articles cast from high pressure polyethylene have insufficient stress cracking resistance and low temperature impact resistance. The blends of polar copolymers with high density polyethylene, although better than high density polyethylene in these properties, are very expensive to make, less transparent, have a stronger odor, poorer electrical properties, and high hexane extractables content, and when mixed with pigments often color precipitation occurs.

It has now unexpectedly been found that articles made by injection molding, rotational molding and blow molding, which consist of low density ethylene-hydrocarbon copolymers having a molecular weight distribution Mw / Mn in the range of 2.7 to 4.1, a total unsaturated group content of 0 , 1 his 0.3 C = C / 1000 C-atoms and a density of 0.90 to 0.94, have a better stress cracking resistance and better properties at low temperatures. In addition, these items have a strong surface gloss and are free of cloudy streaks. Articles cast from these copolymers also have excellent flexibility, especially transverse to the direction of their orientation.

The copolymers used according to the invention are copolymers of predominantly (at least 90%) ethylene and a minor proportion (at most 10%) of one or more C.₃-C_8th-α-olefins. The C₃ -C "α-olefins should not bear branching on any of the C atoms which is closer than the fourth C atom. These α-olefins include propylene, butene-1, pentene-1, hexene-1, 4-methylpentene-1, heptene-1 and octene-1. The preferred α-olefins are propylene, butene-1, hexene-1, 4-methylpentene-1 and octene-1.

The copolymers have a melt flow ratio of 22 to 32, preferably 25 to 30.

Melt flow ratio values ​​are another means of expressing the molecular weight distribution of a polymer. The melt flow ratio of 22 to 32 corresponds to a range of Mw / Mn values ​​of about 2.7 to 4.1, and the range of melt flow ratio of 25 to 30 corresponds to a range of Mw / Mn values ​​of about 2.8 to 3.6.

The melt index of a homo- or copolymer is an expression of its molecular weight. Relatively high molecular weight polymers have a relatively low melt index. Extremely high molecular weight ethylene polymers have a high load melt index of near 0.0, and high molecular weight ethylene polymers have a high load melt index of 0.0 to 1.0. Such high molecular weight polymers are difficult or even impossible to pour in conventional injection molding equipment. However, the polymers mentioned can easily be cast in such plants. They have a melt load at normal load of 0.0 to about 100 and preferably 0.5 to 80, and a high load melt index of about 11 to 2000. The melt index of the polymers used is a function of a combination of the polymerization temperature during the reaction, the density of the copolymer, and the ratio of hydrogen to monomer in the reaction system. Thus, the melt index is raised by increasing the polymerization temperature and / or by lowering the density of the polymer and / or by increasing the ratio of hydrogen to monomers. Other than hydrogen, other chain transfer agents such as dialkylzinc compounds can be used to further increase the melt index of the polymer.

The copolymers used in the invention have a content of unsaturated groups of at most 1, usually from 0.1 to 0.3, CC double bonds / 1000 carbon atoms. You have further

No. 3,667,443 has an n-hexane extractable content (at 50 ° C) of less than about 3% by weight, preferably less than about 2% by weight, and a catalyst residue content, expressed in terms of

<td>TpM titanium metal, in the</td><td>Order of magnitude</td><td>to</td><td>TO</td><td>20</td><td>ppm</td><td>at</td><td>one</td><td>productivity</td><td>from</td><td>min-</td>

<td>at least 50,000 and in the</td><td>Order of magnitude</td><td>to</td><td>to</td><td>10</td><td>ppm</td><td>at</td><td>one</td><td>productivity</td><td>from</td><td>min-</td>

<td>5 at least 100000 and in the</td><td>Order of magnitude</td><td>to</td><td>to</td><td>3</td><td>ppm</td><td>at</td><td>one</td><td>productivity</td><td>from</td><td>min-</td>

The content of chlorine, bromine and iodine residues, which depends on the Cl, Br and J ratios in the starting compound, can be calculated from the ratio of titanium to chlorine, bromine or iodine in the starting material, if the Productivity based on titanium residues is known. For many of the copolymers used according to the invention, which were prepared only with chlorine-containing components of the catalyst system (Cl / Ti = 7), a content of chlorine residues of up to 140 ppm at a productivity of at least 50,000, of up to 70 ppm at a productivity of at least 100,000 and up to 20 ppm with a productivity of at least 300,000. The copolymers can be readily prepared with productivities up to about 1,000,000.

The copolymers used in the present invention are granular materials having an average particle size of the order of 0.125 to 1.8 mm, preferably 0.5 to 1.0 cm in diameter. The particle size is important because the polymer particles in the fluidized bed reactor, as described below, should be readily fluidizable.

The copolymers used according to the invention have a bulk density of 240 to

500 kg / m³,

For the manufacture of articles such as gaskets, closures, food and waste containers, dishes, toys and the like which are said to have excellent stress cracking resistance and / or toughness at low temperatures, gloss and good flexibility, the preferred copolymers are those having a density of 0.918 to 0.935, a molecular weight distribution 25 Mw / Mn of 2.7 to 4.1, a standard melt index of 1 to 100, preferably from 7 to 80, and a secant modulus of 2100 to 5600 bar.

The copolymers used according to the invention can be prepared according to the procedure of EP-OS 0004645, which will be briefly described later, and according to the procedure of EP-OS 0004647, or other processes for the preparation of ethylene-hydrocarbon Co30 polymers having the properties mentioned.

The copolymers can be readily prepared in a low pressure gas phase process in a fluidized bed, as described later, when the monomer feed is polymerized under specific operating conditions, as will be mentioned later, in the presence of a particular high activity catalyst, which will also be described later.

The compounds used to prepare the highly active catalyst comprise at least one titanium compound, at least one magnesium compound, at least one electron donor compound, at least one activator compound and at least one inert carrier material.

The titanium compound has the formula

Ti (OR) X from where

R is an aliphatic or aromatic hydrocarbon radical having 1 to 14 C atoms or COR ', where R' is an aliphatic or aromatic hydrocarbon radical having 1 to 14 C atoms,

X is chlorine, bromine, iodine or a mixture thereof, a is 0 or 1, b is 2 to 4 and the sum of a + b is 3 or 4.

The titanium compounds may be used singly or in combination and include:

TiCl₃, TiCl ", Ti (OC₆ H_s ) C1₃ , Ti (OCOCH₃ ) C1_S, Ti (OCOC₆ H₅ ) C1₃, Ti (OCH₃ ) C1₃,

The magnesium compound has the formula

- 4 No. 367443

MgX₂ wherein

X is chlorine, bromine, iodine or a mixture thereof.

Such magnesium compounds may be used singly or in combination and include MgCl₂ , MgBr₂ and Mgl₂ , Anhydrous MgCl₂ is the most preferred magnesium compound.

About 0.5 to 56, preferably about 1 to 10, moles of the magnesium compound are used per mole of titanium compound in the preparation of the catalyst used in the invention.

The titanium compound and the magnesium compound should be used in a form which facilitates their dissolution in the electron donor compound, as explained later.

The electron donor compound is an organic compound which is liquid at 25 ° C, in which the titanium and magnesium compounds are partially or completely soluble. The electron donor compounds are known as such or as Lewis bases.

The electron donor compounds include, for example, alkyl esters of aliphatic and aromatic carboxylic acids, aliphatic ethers, cyclic ethers and aliphatic ketones. Among these electron donating compounds, the preferred compounds are alkyl esters of saturated aliphatic carboxylic acids having 1 to 4 carbon atoms, alkyl esters of aromatic carhonic acids having 7 to 8 carbon atoms, aliphatic ethers having 2 to 8, preferably 3 to 4 carbon atoms, cyclic Ether having 3 to 4 carbon atoms and preferably cyclic mono- or Diäther with 4 C-atoms, and aliphatic ketones having 3 to 6, preferably 3 or 4 C-atoms. The most preferred compounds among these electron donating compounds are methyl formate, ethyl acetate, butyl acetate, ethyl ether, hexyl ether, tetrahydrofuran, dioxane, acetone and methyl isobutyl ketone.

The electron donor compounds may be used singly or in combination.

About 2 to 85 moles, preferably about 3 to 10 moles of the electron donor compound are used per mole of titanium.

The activator compound has the formula

Al (R)_cX'd^He in which

X^I Chlorine or the group OR 'means

R and R ', which are the same or different, are saturated hydrocarbon radicals having 1 to 14 C atoms, d is 0 to 1.5 e 0 or 1 and the sum c + d + e = 3.

Such activator compounds can be used singly or in combination and include, for example, Al (C₂H₅)₃, A1 (C₂H_s)₂C1, AKi-Cj H₉ )₃ , Al₂ (C₂ H ₅ )₃ Cl₃ , AKi-Cj H₉ )₂ H, A1 (C₆H₁₃)₃, A1 (C_8thH")₃, A1 (C₂H_s)₂H and A1 (C₂H₅ )₂ (0C₂H₃).

About 10 to 400 moles, preferably about 10 to 100 moles of activator compound are used per mole of the titanium compound in activating the catalyst.

The support materials are solid, particulate porous materials which are inert to other components of the catalyst mixture and to other active components of the reaction system. These support materials include inorganic materials such as the oxides of silicon and aluminum, and organic materials such as olefin polymers such as polyethylene. The support materials are used in the form of dry powders having an average particle size of from 10 to 250 μm, preferably from 50 to 150 μm. These materials preferably have a specific surface area of ​​at least 3 m²/ g, preferably at least 50 m²/G. The carrier material should be dry, ie free of absorbed water. The drying of the support material is achieved by heating to a temperature of at least 600 ° C. On the other hand, the support material, which has dried at a temperature of at least 200 ° C,

No. 5,644,443 are treated with about 1 to 8% by weight of one or more of the abovementioned aluminum alkyl compounds. This modification of the carrier by the aluminum alkyl compounds results in a catalyst mixture having enhanced activity, and the ethylene polymers made therewith have better polymer morphology.

The catalyst used to prepare the copolymers used in the present invention is obtained by first preparing a precursor compound of the titanium compound, the magnesium compound and the electron donor compound in one or more stages as described later, and then the precursor compound having the support material and the activator compound in one or more of the above several stages, as described later.

The precursor is prepared by dissolving the titanium and magnesium compounds in the electron donor compound at a temperature between about 20 ° C and the boiling point of the electron donor compound. The titanium compound may be added to the electron donor compound before or after the addition of the magnesium compound or simultaneously. The dissolution of the titanium and magnesium compounds can be facilitated by stirring and in some cases by refluxing. After the titanium and magnesium compounds have dissolved, the precursor is isolated by crystallization or precipitation with an aliphatic or aromatic hydrocarbon having 5 to 8 C atoms such as hexane, isopentane or benzene.

The crystallized or precipitated precursor is in the form of fine free flowing particles having an average particle size of about 10 to 100 pm and a bulk density of about 290 to 530 kg / m³ isolated.

Particle sizes of at least 100 microns are preferred in a fluidized bed process.

The particle size of the isolated precursor compound can be controlled by the rate of crystallization or precipitation.

The precursor compound prepared in the manner described above has the formula

MgTi (OR) X [ED] ⁶mxnp^{l J}q

That means

ED is the electron donor compound, m is a number from 0.5 to 56, preferably from 1.5 to 5, n is a number from 0 to 1, p is a number from 6 to 116, preferably from 6 to 14, q is a number from 2 to 85, preferably from 4 to 11,

R is an aliphatic or aromatic hydrocarbon radical having 1 to 14 carbon atoms or COR ', wherein R' is an aliphatic or aromatic hydrocarbon radical having 1 to 14 carbon atoms, and

X is chlorine, bromine, iodine or a mixture thereof.

The polymerization activity of the fully activated catalyst is so high that dilution of the precursor compound with the support material is necessary to effectively control the rate of reaction. Dilution of the precursor compound may occur before the precursor compound is partially or fully activated, as described below, or concurrently with this activation. The dilution of the precursor compound is achieved by mechanical mixing of 0.033 to 1 part, preferably 0.1 to 33 parts of the precursor compound with 1 part by weight of support material.

The precursor compound must be fully activated, ie it must be treated with enough activator compound to convert the titanium atoms in the precursor compound to an active state. However, it has been found that the nature of the activation of the catalyst is very critical, even when an inert carrier is present. Attempts to activate the catalyst by a process similar to that of US Pat. No. 3,989,881, wherein the entire amount of the theoretically required reducing agent for full activation of the catalyst is added to the precursor compound in a slurry in a hydrocarbon, whereupon the slurry is heated at temperatures of Dried at 20 to 80 ° C to remove the solvent

In order to facilitate the use of the catalyst in a gas phase process, a product which is not sufficiently active in the gas phase fluidized bed process for commercial yield

Purposes was.

It has been found that in order to prepare a useful catalyst, activation must be carried out in such a way that at least the last stage of activation is carried out in the absence of a solvent to avoid drying of the fully activated solvent removal catalyst.

To achieve this result, two approaches have been developed. According to one method, the precursor compound is fully activated outside the reactor in the absence of solvent 10 by mixing with the activator compound. In this dry mixing, the activator compound is preferably used absorbed on a carrier material. However, this procedure has a drawback since the resulting dry, fully activated catalyst is pyrophoric if it contains more than 10% by weight of the activator compound.

In the second preferred manner of activating the catalyst, the precursor compound is partially activated outside the polymerization reactor with activator compound in a slurry in a hydrocarbon, the hydrocarbon is removed by drying, and the partially activated precursor compound is fed to the polymerization reactor where activation is completed with further activator compound.

In preparing the catalyst by dry blending, the solid particulate precursor compound is contacted and uniformly mixed with solid particles of a porous support material which contain the activator compound. The activator compound is absorbed onto the carrier material of a hydrocarbon in which the activator compound is dissolved, so that a loading of about 10 to 50 wt .-% activator compound is achieved on 90 to 50 wt .-% of carrier material. The amounts of precursor compound, activator compound and support material are chosen so that the desired molar ratio of Al to Ti is achieved, and that in the finished compound, a weight ratio of precursor to support material of less than 0.5, preferably of less than 0.33, given is.

The amount of support material thus entails the necessary dilution of the activated catalyst in order to allow the desired control of the polymerization activity of the catalyst in the reactor.

If the final compound contains greater than about 10% by weight activator compound, it is pyrophoric. During dry mixing, which may be performed at room temperature (25 ° C) or below, the dry mixture is kept well agitated to prevent the evolution of heat during the progressive reduction reaction, which is initially exothermic. The resulting catalyst is then completely reduced and activated and can be input to the polymerization reactor as such. It is a free-flowing, particulate material.

In the second preferred method of activating the catalyst, activation 40 is carried out in at least two stages. In the first step, the solid particulate precursor compound diluted with the support material is reacted with, and partially activated, sufficient activator compound to form a partially reduced precursor compound having a molar ratio of activator compound to titanium of from about 1 to 10: 1, preferably from about 4 to 8 : 1, is obtained. This partial activation reaction is preferably carried out in a slurry in a hydrocarbon, whereupon the resulting mixture is dried to remove the solvent at temperatures between 20 and 80 ° C, preferably from 50 to 70 ° C.

The resulting product is a free flowing, solid, particulate material which can be readily fed to the polymerization reactor.

However, the partially activated precursor compound is at best weak as a polymerization catalyst in the process of the present invention. In order to make the partially activated precursor compound active for the purpose of ethylene polymerization, additional activator compound must also be added to the polymerization reactor in order to activate in the reactor

Nr.367443

- 7 to complete the precursor compound. The additional activator compound and the partially activated precursor compound are preferably fed to the reactor through separate conduits. The additional activator compound may be sprayed into the reactor in the form of a solution in a hydrocarbon such as isopentane, hexane or a mineral oil. Such a solution usually contains 2 to 30 wt .-% of the activator compound. The activator compound can also be supplied to the reactor in solid form, absorbed on a carrier material. The support material usually contains 10 to 50 wt .-% activator for this purpose. The additional activator compound is fed to the reactor in such amounts that in the reactor together with the amounts of activator and titanium compound introduced with the partially activated precursor compound, an overall molar ratio of Al to Ti of about 10 to 400, preferably 15 to 60, is reached. The additional amounts of activator compound added to the reactor will react with and complete the activation of the titanium compound in the reactor.

In a continuous gas phase process, such as the fluidized bed process described below, individual portions of the partially or fully activated precursor compound are continuously fed to the reactor, along with optionally added additional activator compound required to complete activation of the partially activated precursor compound. The addition occurs during the course of the polymerization reaction to replace active catalyst sites that are consumed during the reaction.

The polymerization reaction is conducted by passing a stream of the monomers in a gas phase process, such as the fluidized bed process described below, substantially in the absence of catalyst poisons, such as moisture, oxygen, CO, CO₂ and acetylene, with a catalytically effective amount of the fully activated precursor compound, ie the catalyst, at a temperature and a pressure sufficient to maintain the polymerization reaction is brought into contact.

In order to achieve the desired density ranges in the copolymers, it is necessary to copolymerize enough copolymers having at least 3 C atoms with the ethylene to provide from 1 to 10 mol% of the C₃ -C_e Comonomers in the copolymer to achieve. The amount of comonomer required to achieve this result depends on the particular comonomer or comonomers used.

The following is a list of the amounts (in moles) of the various comonomers which must be copolymerized with ethylene to give polymers of the desired density range for a given melt index. The table also indicates the relative molar concentrations of such comonomers to ethylene which should be present in the gas stream of the monomers fed to the reactor:

<td>comonomers</td><td>required mol% in the copolymer</td><td>Mol ratio of comonomers / ethylene in the gas stream</td>

<td>propylene</td><td>3.0 to 10</td><td>0.2 -0.9</td>

<td>Butene-l</td><td>2.5-7.0</td><td>0.2 -0.7</td>

<td>Pentene-1</td><td>2,0-6,0</td><td>0.15-0.45</td>

<td>Hexene-1</td><td>1.0-5.0</td><td>from 0.12 to 0.4</td>

<td>Octene-1</td><td>0.8-4.5</td><td>0.10 to 0.35</td>

The drawing shows a fluidized bed reaction system which is suitable for carrying out the method described. As shown in the drawing, the reactor -10- consists of a reaction zone -12- and a velocity-reducing zone -14-.

Reaction zone 12 comprises a bed of growing polymer particles, already formed polymer particles, and a minor amount of catalyst particles which are fluidized through the reaction zone by a continuous stream of polymerizable and modifying gaseous components in the form of newly added feed and recycle gas. To a arNr.367443

To maintain a workable fluid bed, the flow rate of the gas through the. Must be maintained

Bed above the minimum flow rate required for the fluidization and preferably be 1.5 to loosen, in particular 3 to 6 times this minimum speed.

It is essential that the bed always contain particles to prevent the formation of localized hot spots and to distribute the particulate catalyst throughout the reaction zone. At startup, the reactor is generally loaded with polymer particles before the gas flow begins. These particles may be identical to or different from the polymer to be produced.

If they are different, they are withdrawn together with the desired polymer particles as the first product. Optionally, a fluidized bed of the desired polymer particles replaces the bed used during startup.

The partially or fully activated precursor compound used in the fluidized bed is preferably kept in a reservoir under the gas blanket of a gas inert to the stored material, such as nitrogen or argon, for use.

The fluidization is achieved by a high amount of gas that is returned to and through the bed, with the amount of recirculated gas typically being of the order of 50 times the newly supplied amount of gas. The fluidized bed has the general appearance of a dense mass of working particles in as free a flow as is generated by the passage of gas through the bed. The pressure drop in the bed is equal to or slightly greater than the mass of the bed, divided by its cross-sectional area. So it depends on the geometry of the reactor.

Newly added gas is supplied to the bed in an amount corresponding to the amount in which particulate polymer product is withdrawn. The composition of the newly added gas is determined by a gas analyzer -16- placed over the bed. The gas analyzer determines the composition of the recirculated gas and the newly supplied gas is adjusted accordingly to maintain a substantially uniform gas mixture in the reaction zone.

To ensure complete fluidization, the recycle gas and, if desired, a portion of the recycle gas is fed to the reactor at the entry point -18- in the bottom of the bed. Above this, a distribution plate -20- is arranged to facilitate the fluidization of the bed.

The portion of the gas stream which does not react in the bed represents the recycle gas which is removed from the polymerization zone, preferably via a rate reducing zone -14- above the bed where entrained particles have the opportunity to fall back into the bed. The return of these particles may be promoted by a cyclone -22-, which may be part of the velocity-reducing zone or may be located outside. If desired, the recirculated gas may then be filtered through a filter which is capable of removing small particles at high gas flow rates to prevent dust from contacting the heat transfer surfaces and the compressor blades.

The recirculated gas is then pressurized in a compressor and then released from the heat of reaction in a heat exchanger -26- before being re-fed to the bed. By constant removal of heat in the upper part of the bed no significant temperature gradient can be determined. A temperature gradient exists in the lower part of the bed in a range of about 14 to 30 cm between the temperature of the gas supplied and the temperature of the rest of the bed.

It has been observed that in bed, almost immediately, the temperature of the recirculated gas above this bottom layer of the bed is equalized to the temperature of the remainder of the bed, whereby the bed is maintained at a substantially constant temperature under steady state conditions. The recycled gas is fed to the reactor at the bottom thereof and passes through the distribution plate -20- into the fluidized bed. The compressor -25- can also only

No. 367443 after the heat exchanger -26- be arranged.

The distribution plate -20- plays an important role in the operation of the reactor. The fluidized bed contains growing and already formed polymer particles as well as catalyst particles. Since the polymer particles are hot and possibly active, they must be prevented from settling because, when a quiescent mass is present, the active catalyst present therein can continue to react and cause fusion. The distribution of recycle gas through the bed with sufficient velocity to maintain fluidization at the bottom of the bed is therefore important. The distribution plate -20- serves this purpose and may be a sieve, a slotted or perforated plate and the like. his. The parts of the plate may be stationary or the plate may be of the type described in US Pat. No. 3,298,792. Whatever its shape, it must disperse the recirculated gas through the particles at the base of the bed to keep it in a fluidized state, and can also support a quiescent bed of resin particles when the reactor is not operating. The moving parts of the plate can be used to remove polymer particles held on or in the plate.

Hydrogen can be used as a chain transfer agent in the polymerization reaction. The ratio of hydrogen to ethylene will vary between about 0 and 2 moles of hydrogen per mole of monomers in the gas stream.

Any inert gas to the catalyst and reactants may also be present in the gas stream. The activator compound is preferably fed to the reaction system at the hottest point of the gas stream, which generally precedes the heat exchanger -26-. Thus, the activator may be input to the recirculated gas stream from a dispenser -27- through line -27A-. Compounds of the formula Zn (R KR ^), where R_&amp; and identical or different aliphatic or aromatic hydrocarbon radicals having 1 to 14 carbon atoms, can be used together with hydrogen to act in the catalysts used to control the molecular weight or as a chain transfer agent, ie to increase the melt index of the copolymers produced. About 0 to 50 moles, preferably about 20 to 30 moles, of the zinc compound / mole of titanium compound may be added to the gas stream in the reactor. The zinc compound is preferably fed to the reactor in the form of a dilute solution (2 to 30% by weight) in a hydrocarbon or on a solid support material, such as silica, in amounts of about 10 to 50% by weight. These agents tend to be pyrophoric. The zinc compound may be added alone or with additional amounts of activator compound added to the reactor from a donor, not shown, which may be located near the donor near the hottest part of the recirculated gas system.

It is important to operate the fluidized bed reactor at a temperature below the sintering temperature of the polymer particles. To ensure that no sintering occurs, operating temperatures below the sintering temperature are desirable. For the production of ethylene copolymers in the process according to the invention an operating temperature of 30 to 115 ° C is preferred, with a temperature of 75 to 95 ° C is particularly preferred. Temperatures of 75 to 95 ° C are used to obtain products with a density of 0.91 to 0.92, and temperatures of 80 to 100 ° C are used to produce products with a density of 0.92 to 0.94 to obtain.

The fluidized bed reactor is operated at pressures up to 70 bar and preferably at a pressure of 10.5 to 25 bar, with operation at the higher pressures favoring heat exchange, since increasing the pressure increases the heat capacity of the gas.

The partially or fully activated precursor compound is fed to the bed at a rate equal to its rate of consumption at a point -30- above the distribution plate -20-. The introduction of the catalyst at a point above the distribution plate is an important feature of the invention.

Since the catalysts used are highly active, introduction of the fully activated catalyst into the space below the distributor plate could cause polymerization in this range and possibly result in misplacement of the distributor plate. bring

No. 3,667,444, however, promotes the distribution of the catalyst throughout the bed and makes the formation of localized sites of high catalyst concentration unlikely, which could cause the formation of hot spots.

A gas inert to the catalyst, such as nitrogen or argon, is used to introduce the partially or fully reduced precursor compound and, optionally, additional activator compound or required non-gaseous chain transfer agent into the bed.

The rate of production of the bed is controlled by the rate of catalyst introduction. The production rate can be increased simply by increasing the rate of catalyst addition and vice versa.

Since any change in the rate of addition of catalyst also affects the evolution of heat, the temperature of the recirculated gas is adjusted up or down to account for the change in heat generation. This ensures maintenance of a largely constant temperature in the bed. Full instrumentation of both the fluidized bed and the recirculating gas cooling system is, of course, necessary to detect any temperature change in the bed and to allow for a corresponding correction in the temperature of the recirculated gas.

Under given operating conditions, the fluidized bed is maintained at a substantially constant level by withdrawing a portion of the bed as a product at a rate equal to the rate of formation of the particulate polymer product. Since the amount of heat generation is directly related to product formation, a measurement of the temperature rise of the gas in the reactor (difference between temperature of the incoming gas and temperature of the outflowing gas) can be used for the determination of the rate of formation of the particulate polymer at a constant gas velocity.

The particulate polymer product is preferably present continuously at point -34- at or near the distribution plate -20-, in suspension with a portion of the gas stream which precedes settling of the particles to prevent further polymerization and sintering as the particles reach the collection zone taken from. The suspending gas may also be used, as mentioned above, to overdrive the product from one reactor to another.

The particulate polymer product is advantageously withdrawn, preferably by the action of a pair of timed valves -36 and 38- which define a deposition zone -40-. While the valve -38- is closed, the valve -36- is open for the discharge of gas and product into the zone -40-. Thereafter, valve -36- is closed and valve -38- is opened to deliver the product to an outer collection zone. The valve -38- is then closed until the next product discharge takes place.

The fluidized bed reactor is provided with a system of suitable openings to allow the bed to be supplied during startup and shutdown. The use of stirring and / or scraping means of the wall is not required.

The highly active catalyst system yields a fluidized bed product having an average particle size of between about 0.125 and 1.8 mm, preferably between about 0.5 and 1 mm, wherein the content of catalyst residues is unusually low. The influx of gaseous monomer with or without inert gaseous diluent is fed to the reactor so that a yield of about 32 to 160 kg / hm³ is reached.

Additives such as fillers, pigments, stabilizers, antioxidants, lubricants, flame retardants, UV absorbers, plasticizers, foaming agents, etc. may be added to the copolymers in amounts suitable to achieve the desired objective.

The articles made in accordance with the invention using the above-described copolymers are prepared by methods well known in the art, for example by injection molding, rotational molding and the blow molding process.

Articles such as lids, closures, food and waste containers, utensils, and toys are made by piston or screw injection molding techniques well known to those skilled in the art. For example, Renfrew &amp; Morgan in Polythene, 2nd Edition, describe Interscience

- 11 No. 367443

Publisher (1960), pp. 549-570, the injection molding of polyethylene. The articles made using the above-described copolymers are cast in a standard injection molding apparatus wherein the copolymer is heated to a temperature of 180 to 270 ° C in the apparatus until it is soft, and then at a pressure of 36 to 141 is injected into a mold of the desired shape. The copolymer is cooled in the mold to a temperature between 50 and 60 ° C until it has assumed the shape of the mold. The cast article is then removed from the mold.

Articles such as bottles and containers are molded by injection or extrusion blow molding techniques, as are well known to those skilled in the art. For example, Renfrow &amp; Morgan in the above-referenced literature on pages 571-579 describe blow molding of polyethylene. In the blow molding process, the copolymer is heated in the apparatus as described above and then placed in a mold maintained at a temperature near the melting point of the resin, preferably at 80 to 120 ° C. The resin is made into a cylindrical shape and then introduced into another cooling mold of the desired shape and pressed under pressure against the inner walls of the mold and cooled. The article is then removed from the mold.

The extrusion blow molding process consists, for example, in that a piece of pipe is extruded from the copolymer, u.zw. into a two-part mold, which is then closed to close the tube at one of the ends. The tube is then adapted to the internal shape of the mold, for example by air pressure introduced into the extruded body. The casting is then cooled, the mold opened and the finished object removed.

Articles such as large size toys and industrial size food and waste containers are basically formed by rotational molding instead of injection molding because the complicated shapes can be more economically produced by this method. The process of rotational molding is well known and described, for example, in Encyclopedia of Polymer Science and Technology, Vol. 9, Interscience Publisher (1968), pp. 118-137.

In the process, either powdered resin or a fine resin particle batch is introduced into the interior of a metal casting mold, which is then rotated in a hot oven (260 to 315 ° C) until the resin melts and covers the inside of the casting mold. The molten resin metal mold is then fed to a cooler where it is cooled until the molten resin solidifies and assumes the shape of the mold.

Prior to processing the resins according to the methods described herein, the copolymers may be mixed with various additives and then fed to the casting apparatus, or the copolymer may be fed directly to the casting apparatus along with additives.

The molded articles of ethylene-hydrocarbon copolymers may be subjected to further treatment such as coating, painting and the like depending on the intended use of the article.

The properties of the polymers were determined by the following test method:

Density: ASTM-D-1505 - A plate is conditioned for 1 hour at 100 ° C to achieve equilibrium crystallinity. The indication is in g / cm³, All density measurements are carried out in a density gradient column.

Melt index: ASTM D-1238 condition E; Measurement at 190 ° C; In g / 10 min. Flow ratio: ASTM D-1238 condition F; Measured at 10 times that for the test of

Melt index applied weight.

Melt flow ratio: flow ratio / melt index.

Molecular Weight Distribution (Mw / Mn): Penetration Chromatography; Styragel Filling:

Pore ​​size sequence 10 ⁷ , 10⁵ , 10, 10³, 60 Ά; Solvent: Perchlorethylene at

117 ° C; IR analysis is 3.45 pm.

Unsaturation: IR spectrophotometer (Perkin Elmer Model 21) of thickness

0.635 mm; the absorbance is measured for transvinylene at 10.35 pm, for terminal vinyl at 11.00 pm and for vinylidene in the side groups at 11.25 pm. The absorbency per unit length of the thickness is at each

Nr.367443

Wavelength directly proportional to the product of the concentration of unsaturation and the absorptivity. The absorptivities were the literature values ​​of

RJ deKock and PA Hol in J. Poly. Be. Part B, 2, 339 (1964) taken.

The preparation of the precursor compound takes place in the following manner:

In a 5 liter mechanical stirring flask, 16.0 g (0.168 mol) of anhydrous MgCl 2 were added₂mixed with 850 ml of pure tetrahydrofuran under nitrogen. The mixture was stirred at room temperature (25 ° C) while adding dropwise 13.05 g (0.069 mol) of TiCl4. After completion of the addition, the contents of the flask were refluxed for one-half to one hour to dissolve the solids. The system was cooled to room temperature and 3 l of pure n-hexane was added slowly over 15 min. A yellow solid precipitated. The supernatant was decanted off and the solid washed with 3 times 1 liter of n-hexane. The solid was filtered and dried in a rotary evaporator at 40 to 60 ° C. 55 g of the solid precursor compound were obtained.

The precursor compound can be analyzed for Mg and Ti content at this time because magnesium and / or titanium compound may have been lost during isolation of the precursor compound. The empirical formulas used herein are obtained on the assumption that Mg and Ti are still in the form of the compounds in which they were added at the beginning of the electron donor compound and that all the remaining weight of the precursor compound is attributable to the electron donor compound.

Analysis of the solid gave 6.1% Mg, 4.9% Ti. This corresponds to the formula

TimG₂₎G₅ Cl_{8> 8} (THF)_{> 0} (THF is tetrahydrofuran.)

For the activation of the precursor compound two methods are possible.

Method A: This method involves multi-step activation of the precursor compound. The activation is carried out in such a way that the precursor compound is only partially reduced before its introduction into the polymerization reactor and the remainder of the reduction in the reactor is completed.

The desired amount of dry inert carrier material is introduced into a mixing vessel. In the examples described herein, the amount of inert carrier was about 500 g of silica and about 1000 g in the case of a polyethylene carrier. The inert carrier material is then added with a sufficient amount of anhydrous aliphatic hydrocarbon, such as isopentane, to obtain a slurry. This usually requires 4 to 7 ml diluent / g of the inert carrier. The desired amount of precursor compound is then added to the mixing vessel and mixed thoroughly with the slurry. The amount of precursor compound for preparation of the catalyst is 80 to 135 g in the preparation instructions, the precursor compound having a content of elemental titanium of 1 ± 0.1 mmol Ti / g precursor compound.

The desired amount of activator compound required to partially activate the precursor compound is added to the contents of the mixing vessel to partially activate the precursor compound. The amount of activator compound used gives an Al / Ti ratio in the partially reduced precursor material of up to 10: 1, preferably 4 to 8: 1. The activator compound is added to the mixing vessel in the form of a solution containing about 20% by weight of activator compound (triethylaluminum in the examples) in an inert aliphatic hydrocarbon (hexane in the examples). Activation is achieved by thoroughly mixing and contacting the activator compound with the precursor compound. All of these operations are carried out at room temperature and atmospheric pressure in an inert atmosphere.

The resulting slurry is then passed under a stream of dry inert gas such as

Nitrogen or argon at atmospheric pressure and at a temperature up to 60 ° C to remove the hydrocarbon dried. This usually requires 3 to 5 h. The resulting product is in the form of a dry free flowing particulate material in which the

- 13 Nr.367443 activated precursor compound is uniformly mixed with the inert carrier. The dried non-pyrophoric product is stored under an inert gas.

If additional activator compound is added to the polymerization reactor in process A to complete activation of the precursor compound, it may first be absorbed on an inert support material such as silica or polyethylene, or more preferably injected into the reaction zone as a dilute solution in a hydrocarbon such as isopentane ,

When the activator compound is to be absorbed on a silica support, the two materials are mixed in a flask containing about 5 ml of isopentane / g of support material. The resulting slurry is then dried for 3 to 5 hours under a stream of nitrogen at atmospheric pressure and at a temperature of 65 + 10 ° C to remove the hydrocarbon.

When the activator compound is to be injected into the polymerization reaction system as a dilute solution, concentrations of 5 to 10 wt% are preferred.

Whichever method is used to introduce the activator compound into the polymerization reactor for the purpose of completing the activation of the precursor compound, the addition is made at such a rate that the Al / Ti ratio in the polymerization reactor is 10 to 400: 1, preferably 10 to 100 : 1, is held.

Before use, the silica is dried at a minimum of 200 ° C for at least 4 hours.

Method B: In this method, complete activation of the precursor compound is accomplished by mixing the precursor compound with the activator compound absorbed on an inert support material.

The activator compound is absorbed onto the inert support material by slurrying with the support material in an inert hydrocarbon and then drying the slurry to remove the solvent to give a mixture with 10 to 50 wt% activator compound. There are 500 g of silicon dioxide, which was previously dehydrated (4 h at 800 ° C), fed to a mixing vessel.

The desired amount of activator compound is then added as a 20% by weight solution in a hydrocarbon such as hexane to the mixing vessel and mixed (slurried) with the inert carrier at room temperature and atmospheric pressure.

The solvent is then removed by drying the resulting slurry at 65 ± 10 ° C for 3 to 5 hours at atmospheric pressure under a flowing stream of a dry inert gas such as nitrogen. The dried mixture is in the form of free-flowing particles the size of the carrier material.

About 500 g of the dried activator compound present on silicon dioxide (50% by weight silicon dioxide / 50% by weight activator compound) are then introduced into a mixing vessel. The desired amount of precursor compound (80 to 100 g) is also fed to the mixing vessel. The materials are then thoroughly mixed for 1 to 3 hours at room temperature and atmospheric pressure under a dry inert gas such as nitrogen or argon. The resulting mixture is a physical mixture of dry free flowing particles, on the order of 10 to 150 microns in size. During the mixing process, the activator compound present on the support comes into contact with the precursor compound and activates it completely.

During the exothermic reaction that occurs, the temperature of the catalyst mixture should not rise above 50 ° C to avoid substantial deactivation of the catalyst. The resulting activated mixture has an Al / Ti ratio of about 10 to 50 and may be pyrophoric if it contains more than 10% by weight of the activator compound. It is stored under a dry inert gas, such as nitrogen or argon, prior to introduction into the reactor.

Manufacturing Instructions 1 to 13: Ethylene was copolymerized with propylene (Preparation 1 and 2) and butene-1 (Preparation 3 to 13), using a catalyst prepared as described above and activated by Method A to prepare polymers a density of at most 0.4 was used. In each case, the partially activated precursor compound had a molar ratio Al / Ti of 4.4 to 5.8.

The completion of the activation of the precursor compound in the polymerization reactor was carried out with triethylaluminum (as a 5% by weight solution in isopentane in Examples 1 to 3 and 13 and adsorbed on silicon dioxide at a weight ratio of 50/50 in the case of Examples 4 and 5). achieved so that a fully activated catalyst with a molar ratio

Al / Ti from 29 to 140 resulted.

Each of the polymerization reactions was carried out continuously in a fluidized bed reactor for more than 1 hour after reaching equilibrium under a pressure of 22 bar and at a gas velocity which was 5 to 6 times the minimum rate required for maintaining a fluidized bed, giving a yield of 48 to 123 g / m³.H. The reaction system was according to the drawing. It has a lower section with a height of 3 m and an inner diameter of 34.3 cm and an upper section with a

Height of 4.8 m and an inner diameter of 59.6 cm.

In some of the manufacturing instructions, zinc diethyl was added during the reaction (as a 2.6 wt% solution in isopentane) to maintain a constant molar ratio of Zn / Ti. When zinc diethyl was used, the triethylaluminum also became 2.6% by weight

Solution in isopentane added.

Table I below summarizes various operating conditions for Preparations 1-13, namely the amount of precursor compound in the mixture of silicon dioxide and precursor compound, the Al / Ti ratio in the partially activated precursor compound, the Al / Ti content maintained in the reactor. Ratio, the polymerization temperature, the% by volume of ethylene in the reactor, the molar ratio H₂ / Ethylene, the molar ratio of comonomers (C_x) / C₂ in the reactor, the catalyst productivity.

Table I

<td>manufacturing</td><td>By weight X</td><td>Al / Ti Ratio.</td><td>Al / Ti Ratio.</td><td>Temp.</td><td>c "</td><td>Holverh.</td><td>Holverh.</td>

<td>regulation</td><td>preliminary stage</td><td>in preliminary stage</td><td>in reactor</td><td>(° C)</td><td>(Vol Ä)</td><td>Η: / 0,</td><td>c_x/_C.</td>

<td>1</td><td>8.3</td><td>5.8</td><td>40.5</td><td>90</td><td>41.7</td><td>0.492</td><td>0.486</td>

<td>2</td><td>8.3</td><td>5.8</td><td>50.8</td><td>90</td><td>39.7</td><td>0.566</td><td>0.534</td>

<td>3</td><td>20.1</td><td>4.50</td><td>88.3</td><td>85</td><td>56.3</td><td>0.148</td><td>0,450</td>

<td>4</td><td>19.8</td><td>4.40</td><td>26.7</td><td>85</td><td>50.2</td><td>0,350</td><td>0,350</td>

<td>5</td><td>19.8</td><td>4.40</td><td>26.7</td><td>80</td><td>54.1</td><td>0,157</td><td>0,407</td>

<td>6</td><td>6.9</td><td>5.08</td><td>42.0</td><td>85</td><td>49.2</td><td>0.209</td><td>0,480</td>

<td>7</td><td>6.9</td><td>5.08</td><td>33.6</td><td>85</td><td>46.5</td><td>0.208</td><td>0.482</td>

<td>8th</td><td>6.9</td><td>5.08</td><td>28.8</td><td>85</td><td>42.1</td><td>0.206</td><td>0.515</td>

<td>9</td><td>8.3</td><td>5.8</td><td>124.6</td><td>90</td><td>45.1</td><td>0.456</td><td>0.390</td>

<td>10</td><td>8.3</td><td>5.8</td><td>80.8</td><td>90</td><td>42.7</td><td>0.365</td><td>0.396</td>

<td>11</td><td>8.3</td><td>5.8</td><td>52.0</td><td>90</td><td>48.4</td><td>0,350</td><td>0,397</td>

<td>12</td><td>8.3</td><td>5.8</td><td>140.1</td><td>90</td><td>42.6</td><td>0.518</td><td>0.393</td>

<td>13</td><td>8.3</td><td>5.8</td><td>63.5</td><td>90</td><td>40.8</td><td>0.556</td><td>0.391</td>

The following Table II summarizes the properties of granular resins obtained directly from Preparations 1 to 13, namely, density, melt index (MI), melt flow ratio (MFR), bulk density, and average particle size.

Nr.367443

Table II

<td>manufacturing regulation</td><td>density</td><td>MI</td><td>MFR</td><td>bulk density</td><td>average Particle size (mm)</td>

<td>1</td><td>0.927</td><td>22.0</td><td>24.4</td><td>269</td><td>0.584</td>

<td>2</td><td>0.929</td><td>24.0</td><td>23.4</td><td>260</td><td>0.584</td>

<td>3</td><td>0.925</td><td>0.61</td><td>27.1</td><td>269</td><td>0,762</td>

<td>4</td><td>0.931</td><td>12.0</td><td>26.7</td><td>269</td><td>0.698</td>

<td>5</td><td>0.923</td><td>1.47</td><td>28.2</td><td>250</td><td>1,026</td>

<td>6</td><td>0.919</td><td>3.41</td><td>25.9</td><td>269</td><td>1,397</td>

<td>7</td><td>0.925</td><td>2.90</td><td>24.5</td><td>280</td><td>1.498</td>

<td>8th</td><td>0.919</td><td>3.10</td><td>24.6</td><td>260</td><td>1,447</td>

<td>9</td><td>0.929</td><td>16.0</td><td>24.1</td><td>277</td><td>0.584</td>

<td>10</td><td>0.929</td><td>15.3</td><td>24.0</td><td>266</td><td>0.594</td>

<td>11</td><td>0.928</td><td>11.5</td><td>24.1</td><td>268</td><td>0,630</td>

<td>12</td><td>0.929</td><td>20.7</td><td>24.3</td><td>277</td><td>0,655</td>

<td>13</td><td>0.929</td><td>29.2</td><td>26.1</td><td>269</td><td>0.523</td>

Method of Preparation 14 (Control): Control is a commercially available high pressure polyethylene resin prepared in a reactor under stirring at a pressure of 1140 ° C and a temperature of 205 ° C.

Example 1: The resins prepared in Preparations 1 to 14 were processed into dishwashing dishes and lids by injection molding. The sinks were injection molded at a cylinder temperature of 260 ° C, a pressure of 99 bar and a closed mold duration of 44 seconds. The covers were injection molded at a material temperature of 285 ° C, a pressure of 58.7 bar and a duration in the closed mold of 15 s. The lids 10 were cast from a centrally located sprue with an opening of 0.76 mm diameter and a length of 0.76 mm and had a diameter of 15 cm and a

Thickness of 1 cm. The other conditions used are shown in Table III.

Table III

<td></td><td>perforated bowls</td><td>cover</td>

<td>Injection pressure (bar</td><td>99</td><td>58.7</td>

<td>Cylinder temperature (⁰ C):</td><td></td><td></td>

<td>jet</td><td>260</td><td>260 - 288</td>

<td>front</td><td>260</td><td>-</td>

<td>center</td><td>260</td><td>260 - 288</td>

<td>edge</td><td>232</td><td>246 - 274</td>

<td>Casting temperature (° C):</td><td></td><td></td>

<td>movable</td><td>27</td><td>11</td>

<td>stationary</td><td>24</td><td>11</td>

- 16 No. 367443

Table III (Cont

<td></td><td>perforated bowls</td><td>cover</td>

<td>Cycle (s) inject</td><td>12</td><td>2 -3</td>

<td>closed mold</td><td>44</td><td>15</td>

<td>pressure storage</td><td>4</td><td>1.5</td>

<td>precompression</td><td>4</td><td>2</td>

<td>exit</td><td>12</td><td>-</td>

<td>total duration</td><td>72</td><td>18</td>

Each of the resins of Preparation 1 to 14 was tested for its modulus of elasticity according to ASTM D638. Also, the melt index, density and melt flow ratio of these resins are given in Table IV.

The lids were tested for their resistance to stress cracking in Crisco oil. They were bent outward with the edges until the opposite edges touched and piled on top of each other. The kinked portions opposite the edges were then immersed in Crisco-Ö1 until tearing was observed. The results are given in Table IV. The low temperature impact resistance of the sinks was measured at -40 to -51 ° C by placing a 5 kg cylindrical body with a diameter of 2.5 cm and a hemispherical head of ever greater height (each spaced by 7.5 cm enlarged) was dropped onto the drainage area of ​​the bowl until the bowl was broken or punctured. The height from which the failure occurred was multiplied by the weight of the falling body.

The extent of warpage and gloss were determined by visual observation as compared to an otherwise identical test piece prepared under the same conditions from the high pressure polyethylene of the same melt index and density.

Table IV

<td></td><td>Manufacturing instructions 1 to 13</td><td>Herstellungsvorschrif- 1 to 13</td>

<td colspan="3">resin properties</td>

<td>melt index density Melt Flow</td><td>20 0.925 25</td><td>20 0.924 35</td>

<td colspan="3">Property of the object</td>

<td>Secant Stress cracking resistance (duration to failure) Impact strength at -51 ° C (kg.m) Resistance to rejection</td><td>2870 &gt; 21 days 2.88 (Pierced) excellent</td><td>1150 3 min 0.69 (broken) very well</td>

The data show that the articles made from ethylene-hydrocarbon copolymers have higher stiffness {secant modulus), excellent stress cracking resistance, impact resistance, and resistance to warpage compared to articles made from

- 17 No. 367443

High-pressure polyethylene were produced possess.

Manufacturing Instructions 15 to 18: According to the procedure of preparation instructions 1 to 13, copolymers were prepared. The comonomers reacted to produce the copolymer with ethylene, the melt index, the density and the melt flow ratio of the copolymer prepared are summarized in Table V:

Table V

<td>manufacturing regulation</td><td>comonomers</td><td>melt index</td><td>density</td><td>melt flow relationship</td>

<td>16</td><td>Butene-l</td><td>17.8</td><td>0.928</td><td>29</td>

<td>17</td><td>propylene</td><td>19.2</td><td>0.928</td><td>25.5</td>

<td>18</td><td>Butene-l</td><td>29</td><td>0.925</td><td>23</td>

<td>19</td><td>Propylene / butene (50/50)</td><td>29</td><td>0.927</td><td>23</td>

Examples 2 to 5: Each of the polymers of Preparations 15 to 18 was poured into a rinse bowl as described in Example 1, at a cylinder temperature and under a pressure of approximately 8 bar above the minimum mold filling pressure, as in Table VI specified. The low temperature impact resistance of the sinks was measured at -40 to -51 ° C according to the procedure described in Example 15. The results are given in Table VI.

Table VI

<td rowspan="2">example</td><td rowspan="2">Resin from example</td><td colspan="2">casting conditions</td><td colspan="2">Impact strength (kg.m)</td>

<td>Cylinder- temperature (° C)</td><td>Minimal- print (bar)</td><td>-40 ° C</td><td>-51 ° C</td>

<td>2</td><td>16</td><td>260</td><td>87.5</td><td>-</td><td>2.76 (Pierced)</td>

<td>3</td><td>17</td><td>260</td><td>87.5</td><td>-</td><td>2.53⁽¹)</td>

<td>4</td><td>18</td><td>205</td><td>77.0</td><td>3.46 (Pierced)</td><td>2.88 (Pierced)</td>

<td>5</td><td>19</td><td>205</td><td>73.5</td><td>3.00 (Pierced)</td><td>2.64 (Pierced)</td>

(1) 2 out of 6 samples broken

The data show that articles made from the above-described copolymers have excellent impact resistance.

Examples 6 to 9: Each of the polymers of Preparations 15 to 18 was as in

Example 1 potted to cover, with a cylinder temperature and a pressure of about 8.4 bar above the minimum pressure required to fill the mold, as shown in Table VII. The lids were tested for stress cracking resistance in Crisco oil according to the procedure described in Bei20 game 1. The results are summarized in Table VII.

- 18 No. 367443

Table VII

<td rowspan="2">example</td><td rowspan="2">Resin from manufacturing regulation</td><td colspan="2">casting conditions</td><td rowspan="2">stress cracking resistance</td>

<td>Cylinder- temperature (° C)</td><td>Minimal- print (bar)</td>

<td>6</td><td>15</td><td>260</td><td>57.6</td><td>&gt; 21 days</td>

<td>7</td><td>16</td><td>260</td><td>57.6</td><td>&gt; 21 days</td>

<td>8th</td><td>17</td><td>260</td><td>38.5</td><td>&gt; 21 days</td>

<td>9</td><td>18</td><td>260</td><td>38.5</td><td>&gt; 21 days</td>

The data show that articles made from the above copolymers, such as covers, have excellent resistance to stress cracking.

Preparations 19-26: Copolymers with butene-1 of Preparations 19 5-23 were prepared according to the procedure of Preparations 1-13.

The comonomer used, the density, the melt index and the secant modulus of the resulting copolymer are described in Table VIII.

The high pressure polyethylene used in Preparations 24 to 26 is a commercial material.

Table VIII

<td>manufacturing regulation</td><td>comonomers</td><td>density</td><td>melt index</td><td>Secant (bar)</td>

<td>19</td><td>Butene-l</td><td>0.918</td><td>7.0</td><td>2250</td>

<td>20</td><td>Butene-l</td><td>0.926</td><td>12.0</td><td>2880</td>

<td>21</td><td>Butene-1</td><td>0.928</td><td>18.0</td><td>3400</td>

<td>22</td><td>Butene-l</td><td>0.928</td><td>30.0</td><td>3410</td>

<td>23</td><td>Butene-1</td><td>0.937</td><td>7.0</td><td>4900</td>

<td>24</td><td>-</td><td>0.919</td><td>10.0</td><td>1330</td>

<td>25</td><td>-</td><td>0.924</td><td>9.5</td><td>1750</td>

<td>26</td><td>-</td><td>0.926</td><td>28.0</td><td>2030</td>

Examples 10 to 17: The resins prepared in Preparations 19 to 26 were spin-cast into heating tubes. The resins were ground to a powder having a grain size of at most 0.5 mm, and processed in a mold for heating pipes having a cross-sectional area of ​​17.8 cm, a length of 61 cm and an average wall thickness of 15 0.32 cm , The oven temperature was 305 ° C, the cycle time was 12 minutes (except for the resins according to Preparation 21 and 22, in which the cycle time was 8 minutes), and the mold was cooled by spraying with cold water for 3 minutes.

The castability of each of the tested resins was determined. Further, the impact resistance of each sample was measured at -40 ° C using a 5 kg case with a half-ku20 gel-shaped head and a diameter of 2.5 cm dropped from a height of 60 cm. The percentage of samples that failed is given in Table IX. The

Flexural strength, determined at a bending angle of 90 ° with 120 cycles / min, was also for

- 19 No.367443 measured some of the samples prepared by rotational molding. Resistance to

Stress cracking was determined according to ASTM D1693 at a temperature of 50 ° C. These data are summarized in Table IX.

Table IX

<td rowspan="2">Examples</td><td colspan="5">Low pressure resins</td><td colspan="3">High pressure resins</td>

<td>10</td><td>11</td><td>12</td><td>13</td><td>14</td><td>15</td><td>16</td><td>17</td>

<td>Resin from manufacturing specification</td><td>19</td><td>20</td><td>21</td><td>22</td><td>23</td><td>24</td><td>25</td><td>26</td>

<td>castability</td><td></td><td>excellent</td><td></td><td colspan="2">excellent</td><td>out</td><td>drawn</td><td>excellent</td>

<td>Impact resistance (Z)</td><td>100</td><td>100</td><td>100</td><td>100</td><td>100</td><td>100</td><td>0</td><td>0</td>

<td>flexural strength (Cycles for 50% failure)</td><td>150000</td><td>5000</td><td>-</td><td>-</td><td>-</td><td>-</td><td>3000</td><td>-</td>

<td>stress cracking (h to 100% failure)</td><td>&gt; 504</td><td>-</td><td>15</td><td>1</td><td>25</td><td>4</td><td>1</td><td>1</td>

The data show that at comparable modulus and melt index, the low pressure copolymers form rotationally molded articles that are significantly better than high pressure resin articles in terms of low temperature impact resistance, flexural strength, and stress cracking resistance.

Example 18: The butene-1 copolymers of Preparations 19 to 23 became

Molded and then tested for stress cracking resistance in Crisco oil as described above. After 21 days immersion in Crisco oil no cracking was observed in the bent part. Under similar conditions, the high pressure resin of Example 15 ruptured after 3 minutes.

Example 19: The butene-1 copolymers of Preparations 20 to 22 were injection molded into bowls under the conditions described above and then tested for their impact strength at -51 ° C according to the procedure described above. None of the sinks broke. Penetrations in the sinks occurred at the loads indicated in Table X. Dishwashing bowls from the control resin shattered at 0.69 kg.m.

Table X

<td>Resin from Preparation Method</td><td>Impact strength (kg.m)</td>

<td>20</td><td>3.56 (pierced)</td>

<td>21</td><td>2.76 (pierced)</td>

<td>22</td><td>2,87 (pierced)</td>

<td>control resin</td><td>0.69 (broken)</td>

²⁰ Examples 20 to 22: In accordance with the procedure of preparation instructions 1 to 13 were

Butene-1 copolymers produced. As a control, a commercially available high pressure polyethylene was used. For comparison, a low-pressure resin was tested, which has a higher

- 20 No. 367443

Has melt index as both the butene-1 copolymer and the polyethylene.

The resins were cast under pressure into specimens 0.32 cm thick according to ASTM D1928 and tested for stress cracking resistance in 100% Igepal according to the procedure of ASTM D1693. The time until half of 20 cast specimens ruptured was determined at 50 ° C. The results are given in Table XI.

Table XI

<td>example</td><td>20</td><td>21</td><td>22</td>

<td>resin type</td><td>Butene-l-</td><td>high pressure</td><td>low-pressure</td>

<td></td><td>copolymers</td><td>-Polyäthylen</td><td>resin</td>

<td>melt index</td><td>1.0</td><td>2.0</td><td>7.0</td>

<td>density</td><td>0.921</td><td>0.921</td><td>0.918</td>

<td>Secant module (har)</td><td>2680</td><td>1610</td><td>2240</td>

<td>Stress crack resistance (h up to 50% failure)</td><td>&gt; 504</td><td>200</td><td>&gt; 504</td>

The results show that, although the low pressure resins have about 50% higher modulus than the high pressure resin and therefore are subject to higher stress in the bending test, they still have a much better stress cracking resistance than a high pressure resin made in a reactor with 10 stirring of the commercially available polyethylenes is considered to be one of the most resistant to stress cracking. If the melt index of the low pressure resin was increased to 7.0 as in Example 48, the low pressure resin was significantly more stress cracking resistant than the high pressure resin having a melt index of 2.0. Normally, an increase in melt index reduces stress cracking resistance.