JPS60252643A - Rubber composition - Google Patents

Abstract

PURPOSE:To provide a rubber composition having excellent age resistance, processability and breaking strength, by blending a rubber with a copolymer obtained by hydrogenating an aromatic vinyl polymer/diene random copolymer at a specific hydrogenation degree. CONSTITUTION:An aromatic vinyl compound/diene random copolymer having a bonded aromatic vinyl compound content of 3-70(wt)%, preferably 5-55%, an unsaturated bond content of >=12%, preferably >=60% at the side chain of the diene segment, and a polymodal molecular weight distribution pattern, is produced by the anionic polymerization of an aromatic vinyl compound (e.g. styrene) with a diene compound (e.g. butadiene), followed by the coupling reaction with a coupling agent having >=3 functional groups. The obtained copolymer is hydrogenated until >=30%, preferably 50-90% of the unsaturated bond of the diene segment is hydrogenated. The obtained hydrogenated polymer is used as it is, or blended to other rubber component at a ratio of >=20%.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydrogenated random copolymer of an aromatic vinyl compound and a diene compound.

Conventionally, as a hydrogenated polymer, for example, JP-A-56-30
401. 57-2344. 56-30404.

56-30447. No. 56-30455 discloses hydrogenated polybutadiene. Hydrogenated styrene-citadiene block copolymers are also known.

However, although these hydrogenated polymers are generally improved in terms of aging resistance, they are not satisfactory in terms of breaking strength, permanent set, etc.

An object of the present invention is to provide a rubber composition containing a hydrogenated aromatic vinyl compound/Tzen random copolymer having excellent aging resistance, good processability, and breaking strength.

According to the invention, the content of the bound aromatic vinyl compound is from 3 to
An aromatic vinyl compound/diene random copolymer having a polymodal molecular weight distribution of 70% by weight, an unsaturated bond content of 12% or more in the side chain of the diene part, and a polymodal main turn of the molecular weight distribution. A rubber composition containing 20% by weight or more of a copolymer hydrogenated to at least 30 unsaturated bonds is provided.

The aromatic vinyl compound/tzene copolymer used in the present invention is advantageously produced by anionic polymerization.

Aromatic vinyl compounds include styrene, p-methylstyrene, m-methylstyrene, p-tert-butylstyrene, α-methylstyrene, chloromethylstyrene,
Vinyltoluene etc.2>'d are listed.

Preferred examples include styrene, p-methylstyrene,
α-methylstyrene is mentioned.

As the diene compound, butadiene, inglene, entanoene, 2,3-methylbutanoene, etc. are used.

Anionic polymerization is carried out using conventional methods and under known conditions, and alkali metals or alkaline earth metals can be used as polymerization catalysts. Living polymerization using an organic lithium compound catalyst is particularly preferred. Furthermore, in order to contain a branched polymer as a high molecular weight region in the polymer, (1) a cuckling reaction is performed after the polymerization reaction, or (
11) A polyfunctional monomer can be used as a copolymerization component during polymerization.

Examples of the coupling agent used in the cuckling reaction include halides, ester compounds, epoxy compounds, aldehydes, and ketone compounds having at least three functional groups.

Specifically, as the halodane, CCt, S j
CL4, R8ICt3 (here, R is an alkyl group having 1 to 20 carbon atoms), 5nC44, G e C70, CB r4
, aliphatic halides such as tetrachloroethane, hexachlorobutadiene, carbonaceous halides such as trichlorobenzene, tribromobenzene, hexachlorobenzene, hexabromobenzene, or various norodane-containing flame retardants.

As the ester compound, azopic acid diester, terephthalic acid ester, isophthalic acid ester, ethylene carbonate, furopylene carbonate, etc. are used.

As the epoxy compound, epoxidized liquid polybutadiene, epoxidized polyisogrene, epoxidized soybean oil, oxidized linseed oil, etc. are used.

As the polyisocyanate, benzene-1,2,4-
Examples include triincyanate and triphenylmethane triisocyanate.

Further, as the polyfunctional monomer as the copolymerization component in the above (11), for example, sovinylbenzene is used. The proportion of the polyfunctional monomer used is 0.02 to 5 parts by weight based on 100 parts by weight of all monomers.

If the amount is more than this, gluing will occur, and if it is less than this, it will be difficult to obtain a branched polymer.

In the present invention, polymodal means that the molecular weight distribution as determined by Dal Permeation Chromatography (GPC) has a pattern in which peaks are observed at two or more locations. Usually there are 2 to 3 peaks. In particular, the high molecular weight range is at least 3
In the case of a functional branched polymer, the molecular weight distribution is broadened and there is a great advantage in terms of processability. The content of the branched polymer is not particularly limited, but it is preferably contained in an amount of 20% by weight or more from the viewpoint of processability.

Next, the hydrogenated polymer is obtained by hydrogenating a solution of the aromatic vinyl compound/diene random copolymer in an organic solvent under hydrogen pressure in the presence of a catalyst.

The reaction temperature is usually 20 to 150°C, and the pressure is not particularly limited, but it is preferable to increase the hydrogen pressure because the reaction is faster. The hydrogenation reaction time can be arbitrarily selected. Hydrogenation reaction catalysts include Noyaou/Nomucarpine, reduced nickel,
Rhodium-based homoheterogeneous catalysts; or organic nickel compounds such as di-naphthenate, kel, di-octanoate, kel, etc., or organic cobalt compounds such as cobalt heptathenate, cobalt octoate, and triethylaluminum, triimbutylaluminum Organoaluminium compounds such as or n-butyllithium,! Homogeneous catalysts in combination with organolithium compounds such as 160-butyllithium can be used. As a cocatalyst, ether compounds such as tetranohydrofufin, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, etc. may be used.

The hydrogenated copolymer of the present invention has a bonded aromatic vinyl compound content of 3 to 70% by weight, preferably 5 to 55% by weight, and a side chain represented by a 1,2 or 3,4-vinyl structure in the diene moiety. The content of unsaturated bonds is 12 or more, preferably 60
It is a hydrogenated product of a polymodal random copolymer of 1 or more. If the content of the bonded aromatic vinyl compound is less than 3% by weight, the fracture strength is low and is not practical, while if it exceeds 70% by weight, the rubbery properties are lost, the strength is reduced, and the external permanent set becomes large.

In addition, it is industrially difficult to obtain a polymer with a content of less than 12 unsaturated bonds in the side chain, and in order to give the hydrogenated polymer a balance between processability and physical properties, it is necessary to further increase hysteresis loss. The amount of unsaturated bonds in the side chain is preferably 60 or more.

In the present invention, hydrogenation is carried out at a rate of at least 30, preferably 50 to 90, of the unsaturated bonds in the diene portion of the copolymer. If the hydrogenation rate is less than 30 inches, the effect of improving weather resistance and heat resistance will be insufficient, so it is preferable to increase the hydrogenation rate as much as possible. However, depending on the application, it is preferable to leave at least 10% of the unhydrogenated portion for vulcanization.

In addition, when the hydrogenated polymer contains a branched polymer in the high molecular weight range, processability improves, and in addition to aging resistance and fracture strength, hysteresis loss increases, making it a material suitable for vibration-proofing material applications. . This is thought to be due to the introduction of a branched polymer, which increases the number of free end chains when the molecular weight is the same as that of a linear polymer, resulting in an increase in hysteresis loss.

The hydrogenated polymer of the present invention can be used alone or blended with other components. Such rubbers include natural rubber, polyisozolene rubber, emulsion polymerized styrene/butadiene rubber, solution polymerized styrene/butadiene rubber,
High vinyl unhydrogenated SBR in high vinyl polybutadiene
and star polymer, butadiene/acrylonitrile rubber,
Ethylene-propylene or ethylene-noropylene
Examples include diene copolymers, butyl rubber, and halodanated butyl rubber. In the case of a blend, the hydrogenated polymer is 20
If it is less than % by weight, weather resistance, heat resistance, and strength will not be sufficiently improved.

The composition of the present invention may contain compounding agents commonly used in the rubber industry, such as carton black, extender oil, sulfur, vulcanization accelerators, vulcanization aids, anti-aging agents, etc., as necessary. .

There are no particular restrictions on the formulation and vulcanization method of the rubber composition, and each component can be sufficiently mixed using a mixer such as a roll or gunply, and then vulcanized using a conventional method such as a vulcanization press. .

The rubber composition of the present invention is used for various industrial products such as tire materials and anti-vibration rubbers.゛In the following 10 Examples, which will further explain the present invention using Examples, the hydrogenation rate was calculated from the decrease in the quictor of the unsaturated bond in H'-NMR at 100 MHz measured as follows. do. Carbon tetrachloride was used as the solvent and the concentration was 15% by weight. In addition, the branched polymer and remer amount O measurement U GPC (Waters Co., Ltd.
It was calculated from the peak area of the polymer portion of the P-meation chromatograph. The column is 5TYRA (JL
10, 10, 10, 10 (4 feet x 4) were used and 7 trahydrofuran was used as the carrier.

Danro's Rb was used as an index of hysteresis loss. This measurement method was based on B5903. Heat aging resistance is Jx
Measured from sK153oxi.

Example 51 After charging degassed and dehydrated cyclohexane, 100 g of 2000,91 styrene'fI, and 400 g of butadiene into an autoclave, 5 g of tetrahydrofuran, n-
Polymerization was carried out by adding 0.2811 l of butyllithium.

Temperature-rising polymerization was carried out at a polymerization temperature of 30 to 80°C. After the conversion was approximately 100%, 0.169 of 5iCt4 was added. Then, 2,6-tert-butylcatechol was added and the solvent was removed by steam stripping.
Sangle A was obtained by drying with a 20°C heated roll.

In the same manner, the monomer composition, branching agent type, and amount of tetrahydrofuran used were changed to obtain the polymers before hydrogenation of Sandal B to Sandal B shown in Table 1.

The bound styrene (A) obtained above, the vinyl content of the butatsuene moiety (A), and various polymers with different types of branching agents were mixed into 31
It was charged into an autoclave and made into a 15% toluene solution.

After purging the system with nitrogen, add a catalyst solution of nickel naphthenate: n-butyllithium: tetrahydrofuran = 1:8:20 (mole ratio) prepared in advance in a separate container to a ratio of 1 mole of nickel to 1000 moles of polymer. I prepared it like this. Thereafter, hydrogen was introduced into the reaction system, and the reaction was carried out at 60°C. After the desired amount of hydrogenation, the hydrogen in the system was expelled with nitrogen, 2-6-theter Diaryptyrno or Lafresol dissolved in 5 rnl of alcohol was added to stop the reaction, and after removing the solvent by a conventional method, the system was heated to 110°C. After drying with a roll, Samples A to 1 were obtained.

The results are summarized in Table-1. The mixture was kneaded according to the formulation shown in Table 2 and vulcanized at 160° C. for 20 minutes. The results of processability and physical properties are shown in Table 31 and Table 4. The polymer of the present invention has excellent balance between processability and physical properties. Comparative Examples 1, 2, and 3 are inferior to the Examples in breaking strength or workability. Comparative Example-4 has poor heat aging resistance. Furthermore, it is inferior to Example 2 in specific hysteresis loss. Similar results have been obtained in blends with other tsene rubbers.

Table 2 Compounding recipe Parts by weight Polymer 100 HAF Cargen 50 Aromatic oil 10 Stearic acid 2 Zinc white 3 Antioxidant 81ONA*11 Accelerator cz “20.6 // M” 0.6 // D” 0 .4 Sulfur 1.5 Medium I N-phenyl-N-improvy-p-7enylene 7 ph2mine*41,3-sophenyl in 32-mercaptobenzothiazole in 2N-cyclohexyl-2-benzothiazolylsulfenamide Continuation of Guanidine page 1 @ Inventor Yoshihisa Fujinaga @ Inventor Tatsuo Fujimaki Inside Japan Synthetic Rubber Co., Ltd., 2-11-24 Tsukiji, Chuo-ku, Tokyo

Claims (4)

[Claims] (1) The content of the bound aromatic vinyl compound is 3 to 70% by weight, and the content of unsaturated bonds in the side chain of the tsene moiety is 12%.
20% by weight or more of an aromatic vinyl compound/diene random copolymer with a polymodal turn and hydrogenated to at least 30% of the unsaturated bonds in the diene portion. Rubber composition containing. (2) The high molecular weight region of the aromatic vinyl compound/Tsene random copolymer is a branched polymer obtained by reacting the resulting polymer with a coupling agent having three or more functional groups. Rubber composition according to item 1. (3) The content of unsaturated bonds in the side chain of the tsene moiety of the random copolymer is 60 or more, and the content of bound aromatic compounds is 5 to 5.
The rubber composition of paragraph 1 which is 55% by weight. (4) The hydrogenation rate of the above hydrogenated copolymer is 50-9
The rubber composition according to item 1, wherein the rubber composition has a content of 0%.