JPH0778150B2 - Rubber composition - Google Patents

Description

The present invention relates to a hydrogenated rubber-like conjugated diene-based random copolymer for tires and belts having excellent wear resistance, weather resistance, low heat build-up and breaking strength. The present invention relates to a rubber composition containing a coalescence.

“Prior Art” Recently, durability and longevity have been increasingly required for rubber members, and it has become important to improve rubber properties such as wear resistance, weather resistance, and low heat buildup.

Conventionally, polybutadiene has been known as a rubber-like polymer having excellent abrasion resistance, but since it contains a large amount of unsaturated double bonds in the polymer, it was inferior in terms of weather resistance, particularly ozone deterioration resistance.

On the other hand, as a rubbery polymer with excellent weather resistance, ethylene
Propylene / non-conjugated diene copolymers and isobutylene / isoprene copolymers are known, but they are inferior in terms of wear resistance and heat generation.

On the other hand, as a rubber-like hydrogenated conjugated diene-based copolymer having excellent weather resistance, for example, JP-A-56-30401, JP-A-56-30404, JP-A-56-30447, JPA
56-30455, JP 57-2344, JP 60-7
Although disclosed in Japanese Patent No. 9005, all of them are insufficient in terms of carbon dispersion and carbon reinforcement, and are inferior in terms of workability, wear resistance, low heat buildup, and breaking strength.

Further, JP-B-48-30151, JP-A-52-96695 and JP-A-60-252643 disclose a multi-branched hydrogenated conjugated diene copolymer. However,
Compounds such as silicon tetrachloride and divinylbenzene for making the copolymer hyperbranched have low affinity with compounding agents such as carbon and are still insufficient in terms of carbon dispersion and carbon reinforcement, and processability and resistance to Not sufficiently improved in terms of wear resistance, low heat buildup, and breaking strength.

“Problems to be Solved by the Invention” The present inventors have added a functional group for improving carbon dispersion in a polymer molecule in order to satisfy wear resistance, low heat build-up, breaking strength, and weather resistance. Another object of the present invention is to provide a rubber composition containing a polymer in which double bonds in the molecular chain are reduced by hydrogenation.

"Means for Solving Problems" That is, in the present invention, the binding amount of the aromatic vinyl compound is 5 to 5.
A rubbery conjugated diene-based random copolymer having a Mooney viscosity (ML _{1 + 4} , 100 ° C) of 10 to 150 at 40% by weight, and at least 30% of unsaturated bonds of the conjugated diene moiety in the copolymer. Is hydrogenated and at least 20% by weight of the copolymer
However, at the site where metallation occurs due to the copolymer terminal or the organic alkali metal, at least a tin-carbon bond, an aromatic amino group-carbon bond, an aromatic amide group-carbon bond and a phosphate group-carbon bond are selected. A rubber composition comprising at least 20% by weight of a hydrogenated rubber-like conjugated diene random copolymer having one kind of bond, based on the total amount of rubber components.

The hydrogenated rubbery conjugated diene-based random copolymer of the present invention will be described in detail below.

(Production of Copolymer) The copolymer of the present invention comprises 1,3-butadiene as a monomer,
It is a copolymer using a conjugated diene compound such as isoprene, 1,3-pentadiene and 2,3-dimethylbutadiene and an aromatic vinyl compound such as styrene, p-methylstyrene, vinyltoluene and vinylnaphthalene.

The amount of the aromatic vinyl compound bonded is 5 to 40% by weight, preferably 10 to 35% by weight. If it is less than 5% by weight, the tensile properties will be poor, and if it exceeds 40% by weight, it will become resinous and the resilience properties will deteriorate.

A styrene-butadiene copolymer is mentioned as a preferable conjugated diene type random copolymer.

Conjugated diene random copolymer of the present invention is a hexane, heptane, in a hydrocarbon solvent such as cyclohexane, or in an ether solvent such as tetrahydrofuran, ethyl ether-conjugated diene compound and an aromatic vinyl compound -70 ~ 13
Copolymerization can be carried out in the range of 0 ° C. using an organic alkali metal compound such as butyllithium, 1,4-dithiobutane, sodium naphthalene, etc. as an initiator.

Further, a conjugated diene-based copolymer having a vinyl content of 20% or more with less crystal component due to polymethylene chains when hydrogenated is preferable. However, vinyl content is 1,2 of conjugated diene part.
Mean of bonds and / or 3,4 bonds. Vinyl content is 2
When it is less than 0%, the methylene chain of the hydrogenated copolymer becomes long, the amount of crystal components increases, and the exothermic properties deteriorate. On the other hand, if the vinyl content exceeds 80%, the main chain of the copolymer is cleaved during the hydrogenation reaction, which is not preferable.

(Method for Introducing Functional Group) As a method for introducing a functional group into the rubbery random copolymer prior to hydrogenation, the following examples may be mentioned.

An organic alkali metal compound, preferably an alkali metal-terminated conjugated diene polymer obtained by copolymerizing a conjugated diene compound and an aromatic vinyl compound using an organic lithium compound as an initiator, or a conjugated diene-based copolymer The method of reacting at least one selected from a tin compound, an amino-substituted aromatic compound, an isocyanate compound and a phosphate compound with an alkali metallized conjugated diene copolymer obtained by metallization with.

The reaction amount of the functional group per atom of alkali metal is 0.2 to 1.5,
It is preferably 0.7 to 1.3 mol. The number of functional groups introduced into the hydrogenated copolymer is arbitrary, but is preferably 1 to 10 per copolymer chain.

The functional group introduction position is preferably at one end or both ends.

(Functional group) A tin compound contained in the copolymer molecule of the present invention that forms a tin-carbon bond, an amino-substituted aromatic compound that forms an aromatic amino group-carbon bond, and an aromatic amide group-forms a carbon bond. Preferred isocyanate compounds and phosphate compounds forming a phosphate group-carbon bond are compounds having the following two or less functional groups. It is preferably linear in terms of heat generation characteristics.

As the tin compound, dichlorodimethyltin, dichlorodibutyltin, dichlorodioctyltin, halogen compounds such as triphenylmonochlorotin, tetravinyltin, tetraaryltin, divinyldibutyltin, dibutyltin distearate, dibutyltin dioleate,
Alkenyltin compounds such as dioctyltin distearate, dibutyltin maleate, dioctyltin maleate, and carboxylates of alkyltin are also used.

Examples of the amino-substituted aromatic compound include 4,4'-bis (dimethylamino) -benzophenone, 4,4'-bis (dibutylamino) -benzophenone, 4,4'-diaminobenzophenone and 4-dimethylaminobenzophenone.

Examples of the isocyanate compound include phenyl isocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, naphthalene diisocyanate, diphenylmethane diisocyanate, polydiphenylmethane diisocyanate and naphthalene triisocyanate. To be

After reacting the alkali metal-terminated conjugated diene-based copolymer or the alkali metalized conjugated diene-based copolymer with the isocyanate compound, when an excess of the isocyanate group is present, the isocyanate group is water, alcohol, or an amine compound. Aromatic amino group-carbon bond and aromatic amide group-carbon bond can be further formed by reacting with.

Trimethyl phosphate as a phosphate compound,
Triethyl phosphate, tributyl phosphate, trinonylphenyl phosphate, tributylphenyl phosphate, triphenyl phosphate and other trialkyl phosphates, trialkylphenyl phosphates and the like are used.

Tin bound to the copolymer-carbon bond, aromatic amino group-
The bond selected from the carbon bond, the aromatic amide group-carbon bond and the phosphate group-carbon bond must be present in at least 20% by weight of the copolymer molecule. If it is less than 20% by weight, the heat generation property is deteriorated.

(Method of Hydrogenation) The hydrogenated rubber-like conjugated diene-based random copolymer of the present invention is usually dicyclopetadienyl, titanium halide,
Organic carboxylate nickel, cobalt organic carboxylate and 1
~ Hydrogenation catalysts composed of Group 3 organometallic compounds, nickel, platinum, palladium, ruthenium, rhenium, rhodium metal catalysts supported on carbon, silica, diatomaceous earth, etc. as catalysts such as cobalt, nickel, rhodium, ruthenium complexes Under pressure of 1-100 atm of hydrogen, or lithium aluminum hydride, p-toluenesulfonyl hydrazide or Zr-Ti-Fe-V-Cr alloy,
In the presence of a hydrogen storage alloy such as Zr-Ti-Nb-Fe-V-Cr alloy and LaNi ₅ alloy, tin-carbon bond, aromatic amino group-
It is obtained by hydrogenating a conjugated diene-based copolymer having a bond selected from a carbon bond, an aromatic amide group-carbon bond and a phosphate group-carbon bond.

These conjugated diene-based copolymers are prepared by using the above-mentioned hydrogenation catalyst or hydrogenation compound in a hydrocarbon solvent such as hexane, heptane, cyclohexane, benzene, toluene, ethylbenzene or a polar solvent such as methyl ethyl ketone, ethyl acetate, ethyl ether or tetrahydrofuran. Is hydrogenated.

The hydrogenated conjugated diene-based copolymer is obtained by removing the solvent by steam stripping or coagulating with alcohol and then drying.

The hydrogenation rate of the hydrogenated conjugated diene-based copolymer is at least 30%, preferably 50% or more with respect to the double bond of the conjugated diene portion, and when the hydrogenation rate is less than 30%, weather resistance and abrasion resistance are obtained. Is inferior in terms of. On the other hand, when added to polypropylene or polyethylene to improve impact resistance, the hydrogenation rate may be 100%, and for sulfur vulcanization, the hydrogenation rate is 9%.
It is preferably 8% or less, and the upper limit is not particularly limited.

Mooney viscosity (ML) of hydrogenated conjugated diene copolymer
_{1 + 4} 100 ° C.) is 10 to 150. If it is less than 10, wear resistance, breaking strength and heat generation are poor, while if it is 150 or more, workability is poor, which is not preferable.

The copolymer of the present invention can be used alone or as a blend with other rubber components and resin components. Such rubbers include natural rubber, polyisoprene rubber, emulsion polymerized styrene-butadiene rubber, solution polymerized styrene-butadiene rubber, high vinyl polybutadiene, medium high vinyl SBR and star polymers, butadiene-acrylonitrile rubber, ethylene-propylene-. Examples include non-conjugated diene copolymers, butyl rubber, halogenated butyl rubber, polypropylene, polyethylene and the like. In the case of blending, when the copolymer of the present invention is less than 20% by weight, weather resistance, heat resistance and strength are not sufficiently improved.

The copolymer of the present invention may optionally contain compounding agents commonly used in the rubber industry such as silica, calcium carbonate, carbon black, extending oil, sulfur, vulcanization accelerator, vulcanization aid,
Antiaging agents and the like can be added.

The compounding and vulcanizing method is not particularly limited, and after the respective components are sufficiently compounded by a mixer such as a roll or Banbury, the compound can be vulcanized by a usual method such as a vulcanizing press.

The hydrogenated rubber-like conjugated diene-based random copolymer of the present invention is used for various industrial products such as tire materials and anti-vibration rubber.

[Examples] The present invention will be further described with reference to the following examples. In the examples, the hydrogenation rate was calculated from the decrease in the spectrum of the unsaturated bond part of ¹ H-NMR at 100 MHz measured using carbon tetrachloride as a solvent at a concentration of 15% by weight.

The content of functional groups is Fourier Transform NMR Spectrometer
It was determined by a method of integrating for a predetermined time using (FT-NMR) or by atomic absorption analysis.

The hydrogenated copolymer obtained in the present invention was kneaded according to the compounding recipe shown in Table 1 and vulcanized at 160 ° C. for 20 minutes.

The properties of the vulcanized rubber were measured according to JIS K 6301.

Table-1 Formulation method Weight part Hydrogenated copolymer 100 HAF carbon 50 Aromatic oil 10 Stearic acid 2 Zinc white 3 Anti-aging agent 810NA ^{* 1} 1 accelerator CZ ^{* 2} 0.6 accelerator M ^{* 3} 0.6 accelerator D ^{* 4} 0.4 Sulfur 1.5 * 1 N-phenyl-N'-isopropyl-p-phenylenediamine * 2 N-cyclohexyl-2-benzothiazolylsulfenamide * 3 2-mercaptobenzothiazole * 4 1,3-diphenylguanidine The abrasion test was measured by the Lambourn abrasion method.

The measurement conditions are a load of 0.8 kg and a grindstone surface speed of 100 m /
s, test piece speed 130m / s, slip ratio 30%, sand fall 20m
/ min and the measurement temperature is room temperature.

The Lambourn abrasion index is the styrene-butadiene copolymer polymerized with unhydrogenated n-lithium (bound styrene content =
20%, butadiene part vinyl content = 40%, Mooney viscosity =
The wear amount of 45) is shown as 100. The larger the value, the better the wear resistance. Repulsive elasticity (%) was used as an index of exothermicity by the Dunlop elastic reaction test. This measuring method was based on BS903. Repulsive elasticity (%)
The larger is, the less heat is generated and the better. The breaking strength was expressed by the tensile strength at break (kgf / cm ² ).

The ozone resistance was used as an index for the weather resistance.

The measurement conditions were an ozone concentration of 50 pphm, an elongation of 20%, a measurement temperature of 50 ° C., and a visual inspection was performed to evaluate according to the criteria shown in Table 2.

For example, if there are several cracks that can be barely seen with the naked eye, B
Expressed as -2.

Example 1 2000 liters of degassed and dehydrated cyclohexane was added to a 5 l autoclave.
After charging g, 100 g of styrene and 400 g of butadiene, 5 g of tetrahydrofuran and 0.18 g of n-butyllithium were added to carry out polymerization. The polymerization temperature was 30 to 80 ° C.
After the conversion reached about 100%, 0.75 g of 4,4'-bis (dimethylamino) benzophenone (abbreviated as ABP) was added. After that, 2,6-ditertiary butyl catechol was added and the solvent was removed by a steam stripping method.
A copolymer was obtained by drying with a ℃ hot roll.

300 g of the copolymer obtained above was charged into a 5 l autoclave,
It was a 10% toluene solution. After replacing the system with nitrogen,
Nickel naphthenate: triethylaluminum: butadiene = 1: 3: 3 (molar ratio) adjusted in advance in a separate container
The catalyst solution was charged so that 1 mol of nickel was added to 1000 mol of the butadiene portion in the copolymer. Then, hydrogen was introduced into the reaction system at a hydrogen pressure of 30 kg / cm ² , and the reaction was carried out at 80 ° C. After the desired hydrogenation, purge the hydrogen in the system with nitrogen to 5 ml.
2,6-Ditert-butyl para-cresol dissolved in the alcohol of 1. was added, the reaction was stopped and the solvent was removed by a conventional method, followed by drying with a roll at 100 ° C. to obtain a hydrogenated copolymer.

The results are summarized in Table-3.

Examples 2, 5, and 6 A styrene-butadiene copolymer was synthesized by changing the amount of n-butyllithium in the same apparatus as in Example 1 and using the functional bases shown in Table 3. Each of these copolymers was hydrogenated in the same manner as in Example 1 and the vulcanized physical properties were evaluated. The evaluation results are shown in Table-3.

Comparative Examples 1 and 2 A styrene-butadiene copolymer was synthesized in the same manner as in Example 1. However, Comparative Example 1 is an example in which no functional group is used, and Comparative Example 2 is an example in which hydrogenation is not performed.

It can be seen from Comparative Examples 1 and 2 that the hydrogenated copolymer using the ABP of the present invention has very excellent Lambourn abrasion and is unique.

Examples 3 and 4 A styrene-butadiene copolymer was synthesized in the same manner as in Example 1, and the Sn compound shown in Table 3 was used to synthesize tin-butadiene in the copolymer.
A carbon bond was introduced.

Each of the copolymers was hydrogenated with p-toluenesulfonyl hydrazide to evaluate the vulcanization physical properties.

The evaluation results are shown in Table-3.

Comparative Examples 3 and 4 The n-butyllithium content of Example 1 was increased to 0.28 g,
A copolymer of styrene and butadiene was carried out. afterwards,
Silicon tetrachloride or divinylbenzene was added to each by 0.5 mole of n-butyllithium to introduce a functional group.

This copolymer was hydrogenated in exactly the same manner as in Example 1 and the vulcanized physical properties were evaluated. The evaluation results are shown in Table 3.

From Comparative Examples 3 and 4, the hydrides of the polymodal branched copolymers coupled with silicon tetrachloride or divinylbenzene are inferior in tensile strength and wear resistance.

Example 7 Using the polymer polymerized in Example 1, a hydrogenated copolymer having a hydrogenation rate of 35% was synthesized.

The evaluation results are shown in Table 3.

Comparative Example 5 Using the polymer polymerized in the same manner as in Example 1, the hydrogenation rate was
A 25% hydrogenated copolymer was synthesized. The evaluation results are shown in Table 3. From Comparative Example 5, it can be seen that when the hydrogenation rate is low, the weather resistance, wear resistance and tensile strength are low.

Example 8 The amount of tetrahydrofuran added in Example 1 was reduced to synthesize a copolymer having a vinyl content in the butadiene portion of 25%. The hydrogenation reaction was carried out in the same manner as in Example 1. The evaluation results of the hydrogenated copolymer are shown in Table 3.

Comparative Example 6 The copolymerization of styrene and butadiene was carried out in the same manner as in Example 1 except that the tetrahydrofuran of Example 1 was not used and the polymerization was carried out isothermally at 60 ° C. The hydride of this copolymer had a high Mooney viscosity and was poor in processability.

From Comparative Example 6, it is understood that the exothermic property is poor when the vinyl content of the butadiene portion is 20% or less.

Examples 9 and 10 As in Example 1, immediately after the polymerization of styrene and butadiene, AB
Copolymers were obtained by using P addition amounts of 0.5 times and 1.3 times, respectively.

The evaluation results of the hydride of this copolymer are shown in Table 3.

Example 11 The copolymer shown in Table 3 was obtained in the same manner as in Example 1. Then, a hydrogenation reaction was carried out, and the evaluation results of vulcanized physical properties are shown in Table 3.
It was shown to.

Examples 12 and 13 In the same manner as in Example 1, styrene and butadiene were copolymerized. Immediately after completion of the polymerization, a part of the copolymer solution was extracted to obtain a copolymer having no functional group.

On the other hand, n-butyllithium and an equimolar amount of ABP in the remaining copolymer solution in the reactor were added to obtain a copolymer having an aromatic amino group-carbon bond.

In Example 12, 75% of a copolymer having no aromatic amino group-carbon bond and 25% of a copolymer having an aromatic amino group-carbon bond were mixed to synthesize a hydride.

In Example 13, both were mixed at a ratio of 50% to synthesize a hydride.

The evaluation results are shown in Table 3.

Comparative Example 7 15% of the aromatic amino group-carbon bond-containing copolymers synthesized in Examples 12 and 13 and 85% of the aromatic amino group-carbon bond-free copolymers were mixed to produce hydrogen. Compound was synthesized. The evaluation results are shown in Table 3.

EFFECTS OF THE INVENTION The present invention provides a carbon having a bond selected from a tin-carbon bond, an aromatic amino group-carbon bond, an aromatic amide group-carbon bond and a phosphate group-carbon bond in a polymer molecule. It is possible to provide a rubber composition containing a copolymer having good dispersion.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Fumio Tsutsumi 2-11-24 Tsukiji, Chuo-ku, Tokyo Within Nippon Synthetic Rubber Co., Ltd. (72) Inventor Noboru Oshima 2-11-24 Tsukiji, Chuo-ku, Tokyo (72) Inventor Hideki Komatsu 3-5-5 Ogawahigashi-cho, Kodaira-shi, Tokyo (72) Inventor Tatsuo Fujimaki 3-2-3 Fujimi-cho, Higashimurayama-shi, Tokyo

Claims (4)

[Claims] 1. A rubber-like conjugated diene random copolymer having an aromatic vinyl compound content of 5 to 40% by weight and a Mooney viscosity (ML _{1 + 4} , 100 ° C.) of 10 to 150. At least 30% of the unsaturated bonds of the conjugated diene moiety in the polymer are hydrogenated, and at least 20% by weight of the copolymer is tin-containing, either at the copolymer ends or at the sites where metallation occurs due to the organoalkali metal. -Hydrogenated rubbery conjugated diene-based random copolymer having at least one bond selected from carbon bond, aromatic amino group-carbon bond, aromatic amide group-carbon bond and phosphate group-carbon bond A rubber composition comprising the polymer in an amount of at least 20% by weight based on the total amount of the rubber component. 2. A rubber composition according to claim 1, wherein the aromatic vinyl compound is styrene and the conjugated diene is 1,3-butadiene. 3. The vinyl bond content of the conjugated diene moiety is 20-80.
%, The rubber composition according to claim 1 or 2. 4. A copolymer obtained by copolymerizing a conjugated diene and an aromatic vinyl compound by using an organolithium compound as an initiator, and then copolymerizing the copolymer terminal with a bifunctional or less tin compound, an isocyanate compound, an amino-substituted aromatic compound. The rubber composition according to any one of claims 1 to 3, which is a copolymer modified with at least one compound selected from a group compound and a phosphate compound.