Hydrocarbon polymers modified by treatment with silylesters and said silylesters as compounds

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'415554 ?·- 54.376

Κ 44 SPA

IE30RIPTIYA MEMORY

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γ -e, J7-f-7Z to request PATENT OF INVENTION for 20 years

On behalf of SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ BV

Dutch entity established in Carel van Bylandtlaan 30, The Hague, The Netherlands for: A PROCEDURE TO PREPARE A MODIFIED THREADED POLYMER (International Class C08f)

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The invention relates to a process for the preparation of a modified hydrocarbon polymer by treating the polymer with a weight of 0.001-20 $, based on the polymer, of an organic sulfonylazide at a temperature between 115^andC and 25020.

It is known that hydrocarbon polymers ^ including cis-1, 4-polyisoprene, polybutadiene and styrene-butadiene rubber, but particularly polypropylene and polyisobutylene, can be modified by heating with a monosulfonylazide having the formula RSOgN ^, where R represents a radical organic. As the modifying agent, m-carboxybenzene sulfonylazide (ie 3-azido-sulfonylbenzoic acid) can be used. The amount of azide used can vary from 0.001 to $ 20 by weight, based on the polymer to be modified. The sulfonylazide can be mixed with the polymer in a solid state by means of a usual rubber mill or in the form of a solution. The modification procedure is carried out by heating the resulting mixture at a temperature at which the sulfonylazide decomposes, a temperature that can vary from 9020 to 30020. For example, the polypropylene is modified by mixing it with $ 2, based on the weight of the polymer, of 3-pyridino25-sulfonylazide and heating the resulting mixture last

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Two hours at 15O2C, The object of the known method of modification is to prepare products that have improved properties of staining capacity, emulsification capacity and adhesion to other materials.

It has been found that bonded hydrocarbon polymers are also improved in different aspects (for example with respect to crude resistance) by using as a sulfonylazide a silicic ester of an organic sulfonylazide with at least one carboxyl group.

Currently, according to the invention, a process is provided, which comprises adding to a hydrocarbon polymer 0.001-20 by weight -based on the polymer- of a silyl ester of an organic sulfonylazide with at least one carboxyl group, then hydroxylating the silyl ester and heat the mixture to a temperature between 115²C and 25020. silyl esters are new compounds. The invention also relates to silyl esters of organic sulfonylazides with at least one carboxyl group and a process for preparing such esters.

The silyl ester must be mixed with the polymer at a temperature that is below the temperature at which the ester decomposes. It is preferred 3 16-7-73

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re that the silyl ester mix with the polymer at a temperature below 130^β0, particularly less than 12020. The addition of the silyl ester to the polymer at a temperature below 13020 is summarized herein, as follows for the heating of the mixture at a temperature between 115²C and 2502C is called briefly in what follows stage B.

Silyl esters of sulfonylazides with at least one carboxyl group to be used according to the invention may have more than one azidosulfonyl group, but asters with only one azidosulfonyl group are preferred. Silyl esters can be represented by the general formula (N ^ S0₂)_m-A- (0 (0) 0R)_n, wherein A is an organic group, for example a phenylene group, R is hydrogen or a silyl group, and m and n represent integers from 1 to 3, preferably 1, at least one of the R being a silyl group (-SiH ^ R'y, where R * is an organic group, x is 1, preferably 0, and y is 2 or 3, preferably 3, so that x + y = 3).

The silyl esters may be derived from aliphatic sulfonylazides containing at least one carboxyl group, such as the trimethylsilyl ester of 4-azidosulfonyl butyric acid. Preference is given,

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- 4 415554, however, to silyl esters of aromatic azidosulfonylcarboxylic compounds having the above formula, in which A represents an aromatic group, such as a phenylene, tolylene or naphthalene group. The silyl esters can, for example, be derived from 3-azidosulfonylbenzoic acid, 3-azidosulfonyl-6-hydroxybenzoic acid, 3-azidosulfonyl-6-chlorobenzoioo acid, 4-azidosulfonyl-phenoxyatic acid, 4-azidosulfonyl-benzene-l acid, 2-dicarboxylic acid, 5-azi dosulfonyl-naphthalene-l-carboxylic acid, 3-azidosulfonyl-4-neopentylbenzoic acid and 3-azidosulfonyl-4-ethylbenzoioo acid. Excellent results are obtained with the 3-azidosulfonylbenzoic acid trimethylsilyl ester.

The esters can be prepared by silylation of azidosulfonylcarboxylic compounds. By silylation it is generally understood the addition of an organosilyl group (-βίΗθ ^ Ε '^), in particular a trimethylsilyl group, to organic compounds. Known silylating agents are, for example, hexamethyl-disylzazan N-trimethyl-silyl dimethylamine, bis (trimethylsilyl D-aoethamide, bis (trimethylsilyl) trifluoroacetamide, dimethyl-chlorosilane, tetramethyl-disilazane, bromomethyl-dimethyl-olorosilane, odor chlorosilane, bis (chloromethyl) tetramethyl disilazane, and N-trimethyl-si16-7-73

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1-acetamide Trimethylchlorosilane is preferred, a tertiary amine, such as triethylamine, or pyridine, is generally also present to fix the separated H01. The reaction proceeds, for example, according to the following reaction scheme:

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Examples of asidosulfonylcarboxylic compounds that can be silylated in accordance with the invention have been mentioned above.

Suitable conditions for the silylation reaction are: approximately stoichiometric (equimolar) proportions between the silylating agent and the carboxyl groups of the azidosulfo nilio compound; the tertiary amine in an amount that is approximately equivalent to the amount of the separated hydrogen chloride; reaction temperatures between -55²0 and 110SC, preferably between 5^to0 and 80S0j an anhydrous reaction medium; as solvents, for example, toluene, xylene, diethyl ether or disul16-7-73

- 6 415554 carbon furo. Since the reaction is exothermic, it is desirable that the reaction temperature be maintained at the desired level by cooling. The precipitated amine / HOl salt can be filtered off after the reaction is complete and the solvent can be distilled off. If desired, it is also possible to use the silyl ester solution as is.

When used in the modification of hydrocarbon polymers, the silyl ester is preferably in a solution containing 0.001-20% by weight (based on the polymer) of the silyl ester. An amount of 0.01-5% by weight, in particular 0.05-0.5% by weight, of the silyl ester is preferred. These preferred amounts are especially employed in the modification of a diene polymer as a hydrocarbon polymer. The concentration of the silyl ester in the solution may vary between 1 and 90% by weight, in particular between 20 and 60% by weight. Suitable solvents for this solution are those mentioned above as used in the preparation of esters. Solvents particularly suitable for the invention are aliphatic hydrocarbons, such as iso-pentane, n-hexane, iso-oothane, kerosene, lubricating oil fractions, especially when polymers are modified16-7-73

- 7 dianic ros dissolved in aliphatic hydrocarbons.

In this case it is also possible to simply dissolve the silyl ester in the solution of the diene polymer itself; The aster is very easily soluble in it.

The hydrocarbon polymers that can be modified according to the invention can be saturated or unsaturated, crystalline or amorphous, linear or branched. Examples of suitable starting polymers are polyethylene, polypropylene, copolymers of ethylene and propylene, polystyrene and polyisobutene.

The invention is particularly important for polymers of conjugated dienes, such as polybutadiene, cis-1, 4-polyisoprene and random copolymers of styrene / butadiene. Preferably the silyl ester is added to a binder, that is, a solution of the polymer in apolar solvents. The invention can be applied very satisfactorily to isoprene rubbers prepared with a hydrocarbyl lithium or a Ziegler initiator, whose IVL (limit viscosity index) is 2-8 dl / g (measured in toluene at 30SC).

Particularly it is with polymers of oenjugated dienes with which the modification according to the invention has great advantages, in particular when a solution of the polymer is mixed with the so16-7-73

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Silyl ester ester. First, the amount of energy required to mix is ​​much smaller than when the carboxy-sulfonylazide compound is melt mixed with the polymer. In addition, however, mixing can be carried out at a lower temperature. This, combined with the fact that no shear stresses are exerted, or if they are exerted are only small on the polymer, results in no or hardly any degradation of the polymer.

It has been found that sulfur-containing vulcanizable compositions, based on a conjugated diranic polymer modified according to the invention, have substantially improved mechanical properties (crude resistance). Vulcanizable composition is understood as the composition in which all the ingredients required or desired for vulcanization are present and which is therefore suitable for vulcanization. By "qu-e" composition containing sulfur is meant a composition which, based on the polymer, contains at least 0.5 $ by weight of free sulfur or a sulfur accelerator that provides sulfur. The compositions considered also preferably contain an oxide and / or a salt of a divalent metal (such as, for example,

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zinc, lead oxide, zinc stearate, lead stearate or combinations of said oxides with estea rich acid). In addition, other additives, in particular reinforcing fillers, may be present, if desired.

Without reinforcement charges, the mechanical properties of the vulcanizable compositions are used to have optimal values ​​if all these charges and all other additives mentioned above are mixed only with the modified diene polymer obtained in step B - heating to 115-25020 - once that this stage has been completed, preferably the mixing temperature is less than 10020. In some cases it will be preferable, however, that the reinforcement load is already present during the stage

A - mixing of the silyl ester with the polymer at a temperature below 13020 - (and therefore also during step B). In these cases it is essential, however, that the sulfur is only mixed with the modified diene polymer after stage B has been completed, because otherwise vulcanization could take place prematurely. Again, it is preferred to employ a temperature below 10020 during this mixing. As a general rule, the accelerator is added together with the sulfur. Similarly, oxides and / or salts of divalent metals are pre

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fermentedly mixed only with the modified diene polymer after stage B has been completed. If steps A and B have been carried out in the presence of a reinforcing charge and some more azide has been used than would be sufficient if the reinforcing load had been added after stage B, the final vulcanizable compositions will still have a favorable crude resistance.

If desired, a small amount may be used (for example, 1-10 parts by weight for each

100 parts by weight of the diene polymer to be modified) of a treatment oil together with the reinforcing charge during stage A. It is also possible to carry out stage A in the presence of other additives, such as for example antioxidant agents, antioxidants, pigments and fillers non-reinforcing, with the proviso that these substances do not react too strongly with the azide or with its decomposition product during stage A and / or stage B. If it is desired to use spreader oils, which are usually incorporated in relatively large quantities, said oils are generally added only after completing step B.

As explained above, the silyl ester can be mixed with solutions of the

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polymer. It is also possible to mix molten polymer with a silyl ester solution at a temperature below 13020.

According to another method, a solid polymer, for example in the form of a thread or cloth, can be moistened, with the silyl ester, - if it is in a liquid state - or also a solution of the silyl ester, so that only the surface be treated. The temperatures employed are preferably as low as possible, such as the ambient temperature.

After the hydrocarbon polymer has been contacted with the silyl ester solution, the ester is hydrolyzed. This can be done by means of the moisture that is already present, for example, in the mixture of the dissolved polymer and the silyl ester. In the reaction that takes place at room temperature, an organic nyl-carboxylic azidosulfo acid is formed, a disiloxane separating, said acid having the formula (N3SO₂)_m-A- (C (O) OH)_n, where A, m and n have the previous meanings. In the case of a mixture of dissolved polymer and silyl ester, it is advantageous to combine the removal of the solvent with the hydrolysis by steam separating the mixture. Fabrics and threads that are impregnated with the 16-7-73

- 12, π. .

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silyl ter (solution) can also be steam treated to hydrolyze the ester, for example at 1O5⁰C, with the proviso that the polymer still has sufficient dimensional stability at this temperature.

After hydrolysis, the temperature of the polymer, which is mostly still wet, rises to a value between 11520 and 25020 (step B). The azidosulfonyl group then reacts with the hydrocarbon polymer, nitrogen being separated.

The azidosulfonyl group reacts in a short time at a relatively low temperature with the double bonds of the polymer (diene) still present. At temperatures below 20020, preferably between 135²C and 16020, the reaction with a diolic polymer is completed most of the time within 15 minutes, for example between 0.5 and 10 minutes, or saturated polymers such as polypropylene, the reaction proceeds more slowly, for example , for 2 days at 115^SC, 5 hours at 15020 or more than 15 minutes at

16020 If desired, stage B and the hydrolysis stage can be combined.

EXAMPLE I

To a solution of 3-azidosulfonylben25 zoic acid and 1.1 equivalents of pyridine (based on

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acid) in anhydrous diethyl ether, an amount of 1.1 equivalents (based on acid) of trimethylsilyl chloride was added at room temperature with the exclusion of moisture (nitrogen atmosphere). After stirring for 1.5 hours at room temperature, the resulting pyridine / HOl salt was filtered off with the exclusion of moisture.

The filtrate was concentrated under nitrogen under reduced pressure to evaporate ether, pyridine and trimethylsilyl chloride. There was a colorless oil that

- according to infra red spectroscopy analysis - consisted of sustanoraly pure 3-azidosulfonylbenzoic acid trimethylsilyl ester. (Any trace of unreacted acid can be eliminated by incorporating the oil in pentane or hexane and separating the insoluble acid in said phase). The infrared spectrum of the ester was completely identical to the structure considered (there was no absorption corresponding to OH, there is a strong absorption corresponding to azide at 2119 cm^-1 and a strong absorption corresponding to the group 0 = 0 to 1690 cm · '·).

As an additional test of the structure, the ester was treated with water at room temperature, and 3-azidosulfonylbenzoic acid was recovered, which is evidenced by: (a) the melting point (122-12520

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- 14 415554 with decomposition), (b) the mixed melting point with authentic anode (122-12520 oon decomposition), and (c) the infrared spectrum of the hydrolysis product that was identical to that of 3-azidosulfonylbenzoic acid pu5 ro (absorption corresponding to OH at 2800-3300 cm \ absorption corresponding to 0 = 0 to 1665 om "· '' and absorption corresponding to the azido group at 2125 om" ^ ·).

The silyl ester was soluble in swamp, hexane, benzene, amylenes (isopentenes), diethyl ether and chloroform. On the other hand, the acid was insoluble in saturated and unsaturated hydrocarbon solvents.

EXAMPLE II (a) The starting material was a 7 / / by weight solution of polyisoprene with an I7L of 7.0 dl / g in amylenes, which consisted substantially of a mixture of isopentene / isopentane / n-pentane. To this solution, various amounts (see Table 20) of a 50-by-weight solution of 3-azidosulfonylbenzoic acid trimethylsilyl ester were added to 4020, after which the mixture was stirred at this temperature for 0.5 hour. The solvents were subsequently removed by steam separation at 1002C for 0.5 hours, after which the rubber hdme16-7-73

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C was dried under vacuum at 4020 for 20 hours. The dried rubber was then heated at 1502C for 5 minutes.

(h) From the resulting modified polyisoprene rubbers were then prepared vulcanizahles compositions in a Schwahenthan mill at 65^β0

<td>and with a grinding time of</td><td colspan="2">18 minutes</td><td>from</td><td>agreement</td>

<td>with the following recipe:</td><td></td><td></td><td></td><td></td>

<td>Polymer</td><td colspan="2">100 parts</td><td>in</td><td>weight</td>

<td>HAF carbon black</td><td> 50</td><td>II</td><td>II</td><td>il</td>

<td>ZnO</td><td> 5</td><td>n</td><td>II</td><td>II</td>

<td>Stearic acid</td><td> 3</td><td>II</td><td>II</td><td>II</td>

<td>Flectol H (a)</td><td> 1</td><td>II</td><td>II</td><td>II</td>

<td>Santoflex 13 (b)</td><td> 1</td><td>II</td><td>II</td><td>II</td>

<td>Dutrex 729 HP (o)</td><td> 4</td><td>II</td><td>II</td><td>II</td>

<td>Sulfur</td><td> 2,25</td><td>II</td><td>II</td><td>II</td>

<td>Santocure (d)</td><td> 0,9</td><td>II</td><td>II</td><td>II</td>

(a) Registered trademark for pelleted trimethyldihydroqúi nolein (b) Registered trademark for Nl, 3-dimethyl-hut il-N¹-f enyl-paraf enylenediamine (c) -Brand registered for an aromatic oil or treatment (d) Registered trademark for N-cyclohexyl-2-hen zothiazol-sulphene-amide.

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The compositions were subsequently heated in a mold at 8020 for 5 minutes, after which the tensile strength and elongation at break at room temperature were determined.

<td>tea. the</td><td colspan="2">results are shown in</td><td colspan="2">The following table.</td>

<td>I experienced lied</td><td>Parts in the form of asters * silyl / 100 parts of polyisoprene</td><td colspan="3">Vulcanizable composition IV1 (dl / g) of rubber elongation resistance modifies to the traction to in the “do kN / m^¿ break. $</td>

<td colspan="2">(a) for comparison 0</td><td> 157</td><td> 360</td><td> 6,8</td>

<td> 1)</td><td> 0,10</td><td> 920</td><td> 1040</td><td> 5,9</td>

<td> 2)</td><td> 0,15</td><td> 1420</td><td> 950</td><td> 6,8</td>

<td> 3)</td><td> 0,20</td><td> 1420</td><td> 625</td><td> 6,8</td>

EXAMPLE III

To 300 liters of an 18% solution by weight of polyisoprene (prepared with sec-butyllithium in initiator quality, with IVL 6.5 dl / g) in amylenes, an amount of 76 S with trimethylsilyl acid ester was added 3-azidosulfonylbenzoic acid, in the form of a 50% solution by weight of amylenes, (ie 0.2% by weight based on polyisoprene). After stirring for 1 hour the solvent was removed by means of steam (10020,

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0.5 hours) Wet rubber lumps were fed to a FOMMCO extruder. The temperature of the initial section was 12020 and that of the final section 15020. (Like all extruders, a FOMMCO extruder is provided with one or more kneading thymes. The barrel in which the screw rotates is provided with a certain number number of slots that facilitate the removal of water and solvents. The dried rubber is extruded from the machine's rowhead). From the resulting dry rubber (300 g) a vulcanizable composition was prepared according to the previous recipe in a Troester mill at 65²C (18 minutes).

For comparison, the experiment was repeated without the use of 3-azi dosulfonylbenzoic acid trimethylsilyl ester.

<td>Experiment</td><td>IVL of modified rubber (dl / g)</td><td colspan="2">Vulcanizable Composition tensile tensile strength to in ”kN / m^¿) break, $</td>

<td colspan="4">4) with ester</td>

<td>silyl</td><td> 4,0</td><td> 1440</td><td> 1045</td>

<td colspan="4">(b) without it</td>

<td>silyl ter</td><td> 5,7</td><td> 245</td><td> 840</td>

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This application, which corresponds to the one filed in the Netherlands, on June 7, 1972, under NS 7207689, benefits from Article 51 of the current Industrial Property Statute.