CS195719B2 - Method of producing vulcanized elastomers - Google Patents

Abstract

1526482 Vulcanizing liquid diene polymers MICHELIN ET CIE 29 Jan 1976 [30 Jan 1975] 03578/76 Heading C3P Liquid diene prepolymers having a degree of functionality of 1À8-2À0 are vulcanized by (1) forming a mixture thereof with reinforcing filler, a sulphur vulcanization agent and a difunctional chain extender compound in amount such that the ratio of functional groups on the polymer to those on the chain extender is 1, (2) subjecting the mixture to a temperature at which chain extension occurs exclusively, e.g. 20-125‹ C., and (3) subjecting the product to a higher temperature, e.g. above 140‹ C., to effect vulcanization. In Examples, hydroxyfunctional liquid butadiene/styrene copolymers are mixed with carbon black, a conventional sulphur-curing system and methylene diphenyl diisocyanate, and heated first to 110‹ C. and then to 155‹ C. or 160‹ C.

Description

The invention relates to a process for the production of vulcanized elastomers by contacting at least one functional dienic liquid prepolymer, reinforcing agents and reinforcing agents customary for vulcanizing tire casings with a hydrocarbon chain extender compound.

Attempts have been made to provide tire casings whose tread and sides would be formed from vulcanizates made of low molecular weight polymers and / or copolymers carrying reactive functional groups such as hydroxyl or carboxyl groups, which are commonly referred to as liquid functional polymers.

The 'Products data Bulletin n ° 505, 506 and 508 of the Slnclair Petrochemicals Company' discloses the possibility of using vulcanizates based on urea polymers of polyurethanes prepared by the reaction of polyhydroxy diene polymers and / or copolymers, i.e. polymers carrying more than two reactive functional groups, with diisocyanates, in the manufacture of tires used in agriculture and tourism.

However, the properties of tires containing said vulcanizates are not sufficient for said use, as described, in particular, by researchers of the Rubber & Plastics Plastics Research Association (R.A.P.R.A.) in bulletin n ° 6, Vol. 25 November — December 1971 and in a study entitled “Rubber Rubber for Reinforced Rubber Products, A - Technical and Economic Assessment,” and - published by “Rubber and Plastics Research - Associa-”. thion -of Great - Britain ”, where the authors. Daniel, Needham and Pyne argue that "experiments indicate that there is little chance of success in achieving - chain extension and crosslinking of already existing commercial functional liquid polymers bearing - at the chain end - a functional hydroxyl or carboxyl group. These authors further state that. in order to obtain vulcanizates having a Shore hardness sufficient for their use in the manufacture of tire casings and - made from said commercial liquid - polymers, it is necessary to use an increased amount of additives and curing agents, which in turn leads to vulcanizates with insufficient mechanical properties (see Table VII, page 17 of this study) which are not suitable for use in the manufacture of pneumatic tires.

At a conference organized by 'International Union of Pure and Applied

Chemistry '(I.U.P.A.C.) - in September.

Aberdeen - (United Kingdom), featured one of the conference representatives of 'R.A.P. RA that the reaction of polyfunctional liquid native polymers with a long-chain polyfunctional compound results in elastomers having, in the non-vulcanized or vulcanized state, a Shore hardness comparable to that of conventional dienic elastomers, i.e. non-functional elastomers, however, whose mechanical properties are not sufficient for their use in the manufacture of pneumatic tires.

Finally, French Patent Nos. 2,187,805, 2,187,806, 2,187,807,

187 808, 2 187 809, 2 187 842 proposed to use vulcanizate treads for tire casings obtained by reacting polyfunctional (i.e., carrying more than two functional groups) liquid polymers and / or copolymers with polyfunctional polyisocyanates also, wherein the reactants are present in an amount such that chain extension and crosslinking or vulcanization are achieved simultaneously in one and the same phase. Study of examples,. However, it is concluded that said vulcanizates have the same disadvantages as all previous similar vulcanizates.

The present inventor has now found a way to avoid the above-mentioned drawbacks of the prior art processes and has developed a method for producing elastomers derived from functional liquid dienic polymers whose properties are sufficient for their use as essential constituents of the tire casing compositions. '

SUMMARY OF THE INVENTION The present invention provides a process for the production of vulcanized elastomers by contacting at least one functional dienic liquid prepolymer, reinforcing agents and crosslinking agents customary for tire casing vulcanization with a hydrocarbon chain extender compound, comprising at least one functional dienic liquid prepolymer having functionalities in the range of 1.8 to 2, which contain hydroxyl and / or thiol groups as functional reactive groups, and with a molecular weight of from 1000 to 20,000, before contacting with the hydrocarbon chain extender compound, are intimately mixed with reinforcing agents and crosslinking agents; the resulting mixture is contacted with a bifunctional hydrocarbon chain-extending compound containing, as a reactive group - an isocyanate group, the functional dienic liquid prepolymers and a hydrocarbon-extending compound The chain is used - in an amount corresponding to the ratio of the number of reactive groups - the hydrocarbon-chain-extending compound to the number of functional dienic liquid pre-polymer reactive groups equal to 1, whereupon the obtained mixture is first heated to 20 to -140 ° C. achieving the extension of the hydrocarbon chain of the prepolymers. and then, in the second stage, to a temperature of 145 to 200 ° C to achieve crosslinking or vulcanization of the reaction product formed in the first stage.

In the process according to the invention, a hydroxylated butadiene-styrene copolymer is preferably used as the functional liquid dienic prepolymer.

Preferably, mercaptopolybutadiene may also be used as said functional liquid dienic prepolymer.

In order for these vulcanizates to be used in the manufacture of tires as a tire tread and / or tire sidewall material, these - vulcanizates often have to combine mutually opposing antagonistic properties, which in turn constitute a necessary compromise of these properties.

Thus, it is generally contemplated that for use as the main constituent of a tire tread and / or tire sidewall blend, the elastomer-based oil-free blend containing 50 parts of the carbon black (comparative blend) must have the following characteristics:

- Shore hardness less than -70; a 100% elongation module measured after a third traction between 1.17 and 2.45 MPa; A degree of bounce at 60 ° C equal to or greater than 55 pro - butadiene-styrene copolymer containing 25% styrene, equal to or greater than 60 for butadiene-styrene copolymer containing 12% - styrene, equal to or greater than 65 -for polybutadiene cis-1,4; elongation at break and tear strength - equal to or greater than 370% - and 11,7 MPa for polybutadiene, equal to or greater than - 400% and 15,68 MPa for butadiene-styrene copolymer - containing 12% styrene, equal to or greater than greater than 420% and 17,64 MPa for butadiene-styrene copolymer containing 25% styrene; a coefficient of friction of SRT at 20 ° C of greater than -19 for polybutadiene, 35 for a butadiene-styrene copolymer containing 12%. -styrene, 40 for a butadiene-styrene copolymer containing 25% styrene.

Pre-polymers according to the invention are liquid polymers having a molecular weight of less than -50,000, preferably a molecular weight in the range of 1000 to 20,000, the hydrocarbon chain of which is a homopolymer of conjugated dienes or a copolymer of conjugated dienes either with each other. or with vinylaromatic compounds such as polybutadiene, polyisoprene, polypiperylene, polychloroprene, polypentadiene, butadiene-styrene copolymers, butadiene-isoprene copolymers, styrene-isoprene copolymers, butadiene or isoprene copolymers, vinyl chains may be substituted with alkyl radicals, optionally "alkoxy radicals"

or halogens; a conjugated dlen copolymer and a compound of the vinyl nitrile class, such as a butadiene copolymer or isoprene and acrylonitrile or methacrylonitrile; Either terpolymer of conjugated dienes or with each other or with vinyl aromatic compounds and / or vinyl nitriles.

The monomer units are incorporated in the chain either statistically or blockwise, and the amounts (and thus the ratios) of the monomers are variable.

In addition, the liquid prepolymers must be functional, i.e. preferably carry reactive groups such as carboxyl, amino, hydroxyl, thiol or halogen groups on their hydrocarbon chain, and the functionality of the prepolymers must be between 1.8 and 2.

The functionality of the prepolymer is determined by determining the number of supported functional groups, determining the molecular weight of the prepolymer, and coupling reaction using a suitable bifunctional reagent for the functional group supported by the prepolymer, i.e., either a polyaddition or polycondensation agent. The coupling reaction results in a gelatinous product which is practically insoluble if the number of functional groups carried by the hydrocarbon chain is greater than 2 or, if the functionality is equal to or less than 2, to a soluble product, the molecular weight of which can be determined by conventional methods. Functionality can readily be determined by the known reaction on page 438 of the Burnett Handbook, entitled "Mechanism of 'polymer Reactíons", published by Interscience Publishers.

Said functional prepolymers may be used either alone or in combination with one or more bifunctional non-diene polymers such as polyethers, polyesters, polyisobutylene, with low molecular weight bifunctional compounds such as saturated dialcohols, or polymers or with low molecular weight non-functional copolymers such as polybutadiene, polyisoprene, butadiene-styrene copolymer and the like.

"Bifunctional hydrocarbon chain extender" means an organic compound carrying reactive groups capable of reacting with reactive groups in a prepolymer to obtain polyaddition or polycondensation products. Compounds carrying epoxy groups such as glycidyl ether of bis-phenol A, imine groups, for example phenyl-bis- [1- [2-methyl) aziridines 1] phosphine oxide, phenyl-bis- [1- [ 2-ethyl aziridines 1] -benzene-1,3-dicarboxamide, isocyanate groups such as tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate or hexamethylene diisocyanate.

Means commonly used in the manufacture of tire casings are used as reinforcing agents; these substances are carbon black, silicon dioxide, metal reinforcing agents, glass and the like; plasticizers and / or extender oils are also used. These additives must be homogeneously dispersed in the functional prepolymer at the beginning of the process according to the invention.

"Vulcanising or reinforcing additives" means not only substances known under this designation, such as sulfur, peroxides and the like, but also conventional vulcanization accelerators. The vulcanization accelerators used are either inactive compounds to the bifunctional chain-extending compound or compounds which are normally reactive to the chain-extending compound at the polyaddition or polycondensation temperature and which are inactivated in a suitable manner, such as by a suitable encapsulation. Thus, it is possible to use all conventional reagents such as primary amines, secondary amines; 'sulfenamides' of mercaptobenzothiazole and in particular N-di-isopropyl-mercaptobenzothiazole sulfenamide, N-dicyclohexyl-mercaptobenzothiazylsulfenamide; sulfenamides of thiocarbonic acid, such as N-morpholinosulfenamide of N-morpholino-thio-carbonic acid; phosphorus compounds such as bis- [di-isopropyl-thiophosphoryl) disulfide, bis- [diethylthiophosphoryl) trisulfide, zinc dibutyldithiophosphate; guanidines; mercaptotriazines such as 4,4'-disulfide bis [2-N-ethylamine, 6-N-diethylamine, 1, 1 3,5-riazine). It is also possible to add polyaddition catalysts.

In the following, the process according to the invention will be explained in more detail by means of several examples, which are not to be construed as limiting the scope of the invention.

Example 1 \

In this example, two experiments were carried out, namely Ai and Bi, to compare the properties of the reaction product of the hydroxylated polybutadiene commercially available and the di-isocyanate with those of the dysfunctional polybutadiene (Experiment A) and the properties of the hydroxylated reaction product. butadiene-styrene copolymer (the latter being present in the copolymer in an amount of 25% by weight) and a diisocyanate having the properties of butadiene copolymer and a dysfunctional styrene [the latter being present in the copolymer in an amount of 22%. . [Experiment B]] In these two experiments, the ratio of the number of reactive groups of the NCO of the hydrocarbon chain extending agent to the number of reactive groups of the OH prepolymer is 1 at the time of preparation of the mixture.

The reaction conditions used and the results obtained are summarized in Table I below.

TABLE I

Attempt Ai Attempt -Bi

Elastomers 100 wt. % Hydroxylated polybutadiene R-15M, f = 2.2-2.4 Cf. compound: Solpren 200 SBR EN 15 f = 2.5—2.8 Reference compound: SBR 1500 Vulcanization system (weight why) S / Santocur 1 / 1.6 S / Santocur 1.6 / 1 Stearic acid - 1.5 - 2 Carbon black HAF 55 50 55 50 40 10 NA - 1 - - Tolylendilsokyanát 7.7 - 8.1 - ZnO - 4 - 3 Sundex 8125 Duration of vulcanization - 8 5 at 140 ° C (min) Module at 100% 40 40 60 00 elongation (MPa) Degree of rebound 3.07 1.88 3.39 1.86 at 60 ° C Index- according to Scott Relative elongation 58 77.9 54 67 at break (%) Tear strength 297 - 420 404 520 (MPa) 14.2 13.6 18.6 26.4 Shore hardness 72 69 75 68

The abbreviations given in Table I above have the following meanings:

S means sulfur,

R-15-M is liquid hydroxylated polybutadiene, commercially available through Areo, f stands for prepolymer functionality,

Solpren 200 is polybutadiene commercially available from Phlllips,

Santocure is a trademark for N-cyclohexyl-2-benzothiazolesulfenamide, commercially available through Monsanto, SBR CS 15 is a butadiene-styrene copolymer containing 25 weight percent styrene - and commercially available through ARCO,

SBR 1500 is a butadiene-styrene copolymer containing 25 weight percent styrene and commercially available through SHELL,

Sundgx 8125 is an aromatic oil having a concentration of 70 weight percent and a molecular weight of 380, commercially available from Sun Oll, and 4010 NA is N-isopropyl, N‘-phenyl-para-phenylenediamine.

From the above results, it is clear that it is unnecessary to vulcanize the obtained elastomers with sulfur since the modulus and hardness of these elastomers are sufficiently high to use these elastomers in tire casings; on the other hand, the elongation values at break are substantially lower than those necessary for the above application. As a result, the properties of polymers obtained from prepolymers with a functionality greater than 2 and even when the NCO / OH ratio is equal to 1 are insufficient for their use in the manufacture of tire casings.

Example 2

In this embodiment, experiment A2 is carried out by reacting - a hydroxylated butadiene-styrene prepolymer (in which the latter is present in an amount of 25% by weight) - having a functionality of f = -1.97 and a molecular weight 6000, with methylenediphenyl diisocyanate. The ratio of the number of reactive - NCO groups of the hydrocarbon chain extending agent to the number of reactive OH groups of the pre-polymer is equal to 1 when the preparation of the mixtures is complete. At the same time as the polyaddition agent, vulcanizing agents are introduced.

The resulting mixture is then heated at 140 ° C for one hour to perform the polyaddition and vulcanization reactions in a single phase. If performed with the following composition of the mixture:

high abrasion blast furnace carbon black pre-polymer dicyclohexylamine-benzothiazylsulfenamide sulfur ZnO acetylacetonate 9.10 ^-3 per 100 g of iron pre-polymer

100 parts parts

1.7 part

1.5 part

19S719

The resulting properties are summarized in Table II below, where they are compared with those of a reference 'non-functional copolymer (SBR 1500: a copolymer of styrene and' bu10 tadiene with a Money Index of 50 containing 25 wt% styrene 'and 16% linkages). type 1'2}.

TABLE II

Characteristics Experiment Az Reference product:

. SBR 1500

Module at 100% elongation (MPa) 1.97 1.86 19.0 Degree of rebound at 60 ° C 50.3 67 Scott's index - 'elongation at break (%}) 503 590 - tear strength (MPa) 13.2 26.5 The fortress according to, From Above 68 68

Embodiment 2 under similar conditions except that. the reaction mixture is heated at 110 ° C for 20 minutes and then for 20 minutes. on . temperature of 160 ° C to separate the chain elongation and vulcanization phases. The properties of the elastomer obtained and the reference product are shown in Table III below.

It is apparent from the above table that a copolymer having the same properties as the reference product is not obtained, and it is apparent that in particular the degree of rebound and tear strength are substantially lower. That's' culpable. in that the chain extension phase and the vulcanization phase cannot be controlled.

Example 3

The procedure of the example is repeated

TABLE III

Experiment A3 Reference product:

SBR'1500

Module 'at 100% elongation (MPa} 2.05 1.86 Degree of bounce at 60 ° C 60.7 67 Scott 'Index - 'elongation at break (%}) 540 '580 —- tear strength, 25.1 26.5 Shore hardness 68 68

Comparing the properties of 'copolymer A3' with those of Example 2 ', it should be noted that copolymer A3' exhibits improved tear strength (about 9.8 MPa) and about 20% improved degree of rebound at 60 ° C Furthermore, it should be noted that copolymer A3 has almost 'the same properties' as a conventional copolymer.

In addition, driving tests have been carried out on tires having a tread comprising, on the one hand, the copolymer A3 of the present invention and the reference 'classic copolymer' as a constituent, 'for the purpose of comparing the friction coefficients and the wear coefficients, i.e. .

The wear factor 'is expressed as:

test jacket weight loss x 100 • Reference jacket weight loss.

The coefficient of friction is measured at 20 ° C using a skid. reslstance tester (SRT.) ”manufactured by Stanley.

The tire mass losses are determined after the car has been driven on a specified route, with a value of 100 assigned to the reference tire.

The results obtained are summarized in Table IV below.

TABLE IV

Properties

Copolymer Аз

Reference Product: SBR 1500

Coefficient of friction

Weight loss (%)

100 ALIGN!

It can be seen from the above table that the friction coefficient of a tire whose tread consists of a copolymer Аз is about 40 ° / higher than the friction coefficient of a tire whose tread contains a reference product, with a set of both wear properties - grip is better for tread with copolymer Аз.

Examples 4 to 9

In this series of experiments, copolymers were prepared using 100 parts of a hydroxylated butadiene-styrene copolymer (the latter being present in an amount of 12%) with a functionality of 1.97 and a molecular weight of 6000 as a prepolymer. The experiments are carried out with a mixture of the following composition:

blast furnace carbon black with high abrasion 50 parts methylenediphenyl-di- in such an amount,

-isocyanate that in the final mixture the NCO / OH ratio is 1.0 sulfur 1.5 parts of dicyclohexylamine-benzothiazylsulfenamide 1.7 parts

ZnO 4 parts iron acetylacetonate 9.10 ~ ³ g per 100 g of pre-polymer

After homogenization, the mixture was heated at 110 ° C for 20 minutes and then at 160 ° C for 20 minutes. The results obtained are summarized in Table V, which compares the properties of the product obtained with those of a reference copolymer of butadiene and styrene, referred to as Stereon 700, in which styrene is present in an amount of 12% by weight.

TABLE V

Properties 4 5 6 7 Module at 100% elongation [MPa] 1.70 1.69 1.67 1.64 Degree of bounce at 60 ° C 62.6 62.6 '62, 8 62.1 Scott's index - relative elongation at break (%) 600 620 633 613 - tear strength (MPa) 25.2 25.2 26.3 25.2 ISO hardness 58 60 59 59 Table V - continuation Properties 8 9 Reference Product: Stereon 700 #

Module at 100% elongation

(MPa) 1.69 1.70 2.13 Degree of bounce at 60 ° C 62.6 61.8 70 Scott's index - relative elongation at break (%) 60-3 600 480 - tear strength (MPa) 25.5 23.8 17.6 ISO hardness 59 59 66

*) Stereon 700 = styrene-butadiene copolymer with a molecular weight of 140,000 and a Money Index of 61; this copolymer contains 18% by weight of styrene and 9% by weight of type 1 bonds;

It is clear from the above table that the properties of the copolymers thus obtained are substantially identical, which implies that the process according to the invention shows good reproducibility.

In addition, driving tests have been carried out on tires whose treads as the basic constituent - both contain the copolymer of embodiment 4 and - the reference copolymer SBR 1500 and - in order to compare the coefficients of friction and the loss of mass wear of both copolymers. The results obtained are summarized in Table VI below.

TABLE VI

Properties SBR - Obtained in Example '4 Reference Product: SBR 1500 Coefficient of friction '45 45 Weight loss wear (%) 80 100,

From the above table, a better summary of the pair of wear characteristics - tire grip, whose tread as an essential component contains an elastomer prepared by the method according to the invention, is evident.

Example- 10

In this exemplary embodiment, an oil-adjusted elastomer is prepared starting from (as a pre-polymer) from - hydroxylated butadiene-styrene copolymers - containing 12% by weight of styrene and having a functionality of 1.97 and a molecular weight of 6000, and methylene- The amount of diphenyl diisocyanate used as the hydrocarbon chain extender is such that the NCO / OH ratio is equal to 1 in the final mixture.

pre-polymer of 100 parts naphthenic oil with molecular weight - 390 and density,

0,946- (Circosoi - 2 -X - H commercially available from Sun 'Oil) 30 parts of average furnace soot with - - large - abrasion 66 parts

ZnO 5 parts acetylacetonate 45.10 ' ³ g per 100 g iron pre-polymer sulfur 1.17 parts bis- (di-isopropyl-, thiophosphoryl) disulfide 5.56 parts mercaptobenzothiazole monosulfide 0.482 parts

The mixture is then heated at-110 ° C for 20 minutes and at -55 ° C for 22 minutes. The properties of the elastomer obtained are then compared with those of the reference copolymers of butadiene - and styrene set with an aromatic oil in an amount of 37.5 parts, known as Solpren 384; this reference copolymer was cured for 60 minutes at 140 ° C with a mixture of the following composition:

Solpren 384 100 parts average furnace carbon black with great abrasion 50- parts stearic acid 2 parts ZnO 1 part N-isopropyl-N‘-phenylpara- phenylenediamine 1 part N-cyclohexyl-2-benzothiazole- sulfenamide, 1 part sulfur 1.8 part

The properties of the vulcanized compounds obtained are listed in Table VII below.

TABLE VII,

Features - - ¹ SBR according to the invention - Reference product:

. Solpren 384

Module at 100% elongation (MPa) 19.2 18.5 Degree of bounce at 60 ° C 80 70 Scott's index. - relative elongation at break (° / drawbar) 377 420 - tear strength (MPa) 20.6 19.6 Hardness - ISO 63.5 65

It can be seen from the above table that the properties of the oil-adjusted vulcanizate according to the invention remain better than those of the classical. elastomer set by oil ..

Examples 11, 12 and 13

In these examples, three tests were performed using prepolymers having the same molecular weight. weight equal to 6000 and equal functionality

1.98. Compound. The hydrocarbon chain extender is trimethylhexamethylene diisocyanate which is used in such an amount that the ratio of the number of OH groups of the prepolymers to the number of NCO groups of the hydrocarbon chain extender in the finished mixture is equal to 1.

The following Table VI is summarized. the working conditions used in the manufacture of the vulcanizates, and the resulting properties of the vulcanizates. .

TABLE VI

Conditions a. Properties

Example 11

Example 12

Example 12

Copolymer of butadiene and styrene

Elastomers (100 Polybutadiene Styrene content: Styrene content: parts by weight) 12 wt. % 25 wt. % Average furnace carbon black with great abrasion - 50 50 50, ZnO 4 4 4 Iron acetylacetonate (g per 100 g of prepolymers) 6.10-3 '9.10 ~ 3 9.10'3 WITH 1.6 1.6 1.6 Dicyclohexylmercaptobenzo- 1.4 1.4 1.4 Thiazolsulfenamide 30 min 110 ° C 25 min 110 ° C 25 min 110 ° C ! 22 min 160 ° C 22 min 160 ° C 22 min 160 ° C Module 100% extension (MPa) 1.76 1.96 2.06 Degree of bounce at 60 ° C 60 66 60 Scott index: - relative elongation at break (%) 510 500 500 - tear strength (MPa) 20.6 21.6 26.5

Example 14

Test A5 (pre-polymer with SH function)

In this embodiment two tests A4 and A5 are carried out, namely. in order to compare the viscosity of the reaction product of the pre-polymer and diisocyanate with the viscosity reaction product of the pre-polymer with reactive groups SH - (terminal) with the diisocyanate.

Test A4 (comparative)

The hydroxylated butadiene-styrene copolymer, containing 12% by weight of styrene, having a molecular weight of 4600, having a functionality of 1.96, is mixed with 4,4 ' -diphenylmethane diisocyanate in an amount such that the number of OH groups is of the pre-polymer to the number of NCO groups of the hydrocarbon chain extending compound is equal to one in the finished mixture. The mixture was heated at 110 ° C for 1 hour and then at 90 ° C for 24 hours. The reaction product contains no gel.

Mercaptopolybutadiene - having a molecular weight of 11000, - having a functionality of 1.97, is mixed with 4,4‘-diphenylmethane diisocyanate. in such a quantity that - the ratio of the number of - reactive - NCO groups to the number of SH - is equal to one. The mixture is then heated at 60 ° C for 24 hours. The reaction product does not contain a gel.

The above two tests show that the reaction products obtained have an increased viscosity which makes them usable (vulcanized) for tire casings.

Example 15

In this exemplary embodiment, a prepolymer is prepared by reacting 100 parts by weight of a hydroxylated butadiene-styrene copolymer (containing 12% by weight of styrene) having a functionality of 1.97 and a molecular weight of 6000 with 4,4'-diphenylmethane diisocyanate in - the NCO / OH ratio = -1 (in '

ready mixes). The following wording is used:

average abrasive furnace carbon black: 50 parts by weight, sulfur: 0.4 parts by weight, mercaptobenzothiazole disulfide: 0.25 parts by weight,

ZnO: 4 parts by weight, iron acetylacetonate: 9.10 ³ per 100 g of the prepolymer, and bis (diisopropylthiophosphoryl) disulfide: 0.8 part by weight.

After homogenization, the formulation is heated at 110 ° C for 20 minutes and then at 160 ° C for an additional 20 minutes.

The results obtained are summarized in Table VII below.

TABLE VII '

Properties The product according to the invention ^{18 of} styrene (containing 12% by weight of styrene) having a functionality of 1.97 and a molecular weight of 6000, with trimethylhexamethylene diisocyanate in an amount such that the NCO / OH ratio in the finished mixture is 1. The following formulation is used:

average abrasion furnace carbon black: 50 parts by weight, sulfur: 0.4 parts by weight, mercaptobenzothiazole disulfide: 0.25 parts by weight,

ZnO: 4 parts by weight, bis (diisopropylthiophosphoryl) disulfide: 0.20 wt. part.

After homogenizing the mixture, the mixture is heated at 110 ° C for 45 minutes and then at 160 ° C for 20 minutes. '

The results obtained are summarized in Table VIII below.

TABLE VIII

Module 100% elongation (MPa) 2.01 Bounce degree at ° C69.8

Scott index: relative elongation550 at break (%)

Tensile strength (MPa) 28.1

Example 16

In this embodiment, a copolymer is prepared by reacting 100 parts by weight of a hydroxylated butadiene copolymer and / or

Properties Product according to the invention _________________________________________: ______________________________________________________________ i_________________________________________________________________________________________ Module 100% elongation (MPa) 1,83

The degree of bounce at a temperature of ° C61.2

Scott index: relative elongation at break (%) 593

Tensile strength (MPa) 23.9

OBJECT OF THE INVENTION

Claims (3)

OBJECT OF THE INVENTION CLAIMS 1. A process for the production of vulcanized elastomers by contacting at least one functional dienic liquid prepolymer, reinforcing agents and crosslinking agents customary for tire casing vulcanization with a hydrocarbon chain extender compound, characterized in that at least one functional dienic liquid prepolymer having a functionality in the range of 1. , 8 to 2, and a molecular weight of 1000 to 20,000, which contains hydroxyl and / or thiol groups as functional reactive groups, are thoroughly mixed with stiffening and crosslinking agents prior to contact with the hydrocarbon chain extender, and then contacted with the resulting mixture. with a bifunctional hydrocarbon chain-extending compound comprising an isocyanate group as the reactive group, wherein the functional dienic liquid prepolymers and the hydrocarbon chain-extending compound are used in an amount corresponding to a ratio of the number of reactive groups of the hydrocarbon chain-extending compound to the number of reactive groups of the functional dienic liquid prepolymers in the obtained mixture equal to 1, then the obtained mixture is first heated to 20 to 140 ° C in the first stage to obtain an extension of the hydrocarbon chain of the prepolymers in the second step to a temperature of 145 to 200 ° C to achieve crosslinking or vulcanization of the reaction product formed in the first step. 2. The process of claim 1 wherein the functional liquid dienic prepolymer is a hydroxylated butadiene-styrene copolymer. 3. A process according to claim 1, wherein mercaptopolybutadiene is used as the functional liquid dienic prepolymer. Severografi · n. P., Plant 7, Most