JPH08120122A - Production of modified unsaturated rubber-like polymer - Google Patents

Abstract

PURPOSE: To provide a method for producing a modified unsaturated rubberlike polymer capable of supplying vulcanized rubber having improved tensile strength and impact resilience. CONSTITUTION: This method for producing a modified unsaturated rubber-like polymer comprises reacting a solid unsaturated rubber-like polymer to which an alkali metal is added with a compound containing C(=M)-N<bond (in the formula, M shows O atom or S atom) selected from a cyclic amide; one imide selected from the group consisting of succinimide, maleimide, N- methylmaleimide, N-methylphthalimide, 1,2-cyclohexanedicarboxyimide and N-methyl-1,2-cyclohexanedicarboxamide; an amic acid; one urea selected from the group consisting of urea, N,N,N',N'-tetramethylurea and N,N'-dimethyl- ethyleneurea; an isocyanuric acid and a group consisting of thio compounds corresponding to these compounds.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing a modified unsaturated rubber-like polymer, and more particularly to a modified unsaturated rubber capable of giving a vulcanized rubber having improved tensile strength and repulsive elasticity. The present invention relates to a method for producing a rubber-like polymer.

[0002]

2. Description of the Related Art Recently, from the viewpoints of both low fuel consumption and safety of automobiles, reduction of rolling resistance of tires and excellent braking performance on wet road surfaces, that is, improvement of wet skid resistance have been strongly demanded. . In general, the properties of these tires are considered to correspond to the dynamic viscoelastic properties of the tread rubber material, and are known to be properties that are in conflict with each other (for example, Transaction of IR.
I. , 40, 239-256, 1964).

In order to reduce the rolling resistance of the tire, it is necessary that the tread rubber material has a high impact resilience. Considering the running condition of the vehicle, this impact resilience is from 50 ° C to 7 ° C.
It is necessary to evaluate at temperatures up to around 0 ° C. On the other hand, in order to improve braking performance on wet roads, which is an important performance in terms of vehicle safety, it is necessary to have a large wet skid resistance measured by the British Portable Skid Tester. Requires a large amount of energy loss as frictional resistance generated when the tire is braked and the road surface is slipped.

Conventionally, in order to satisfy these two contradictory properties, a styrene-butadiene copolymer rubber having a bound styrene content of 20 to 25% by weight and a high cis 1 having a cis 1,4-bond unit of 80% or more. Although a combination of 4-polybutadiene rubber has been used, it is not satisfactory in terms of wet skid resistance, and attempts have been made to improve wet skid resistance by mixing a resin or rubber having a high glass transition temperature. It is unavoidable that the rebound resilience becomes low, and improvement is demanded.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing a modified unsaturated rubbery polymer capable of giving a vulcanized rubber having improved tensile strength and rebound elasticity. . The present inventors have conducted extensive studies to solve the above-mentioned drawbacks, and as a result, a rubber composition containing an unsaturated polymer rubber obtained by reacting an alkali metal addition unsaturated polymer rubber with benzophenones as a rubber component is It was previously found that even when the same unsaturated polymer rubber was used, the repulsion elasticity could be remarkably improved without changing the wet skid resistance as compared with the case where it was not reacted with benzophenones. 58-189203). Further, as a result of repeated investigations by the present inventors, a compound having -C (= M) -N <bond (in the formula, M represents an O atom or an S atom) in the molecule, instead of the benzophenones. The inventors have found that the use of the above improves the anti-repulsion elasticity as well as the tensile strength, and has completed the present invention.

[0006]

According to the present invention, an alkali metal-added solid unsaturated rubbery polymer and cyclic amides; succinimide, maleimide, N-methylmaleimide, N-methylphthalimide, 1 , 2-cyclohexanedicarboximide, and 1 selected from the group consisting of N-methyl-1,2-cyclohexanedicarboximide.
Seed imides; amic acids; urea, N, N, N ', N'
-In the molecule selected from the group consisting of tetramethylurea and one kind of urea selected from the group consisting of N, N'-dimethyl-ethyleneurea; isocyanuric acids; and a thio compound corresponding to these compounds- Provided is a method for producing a modified unsaturated rubbery polymer, which comprises reacting with a compound having a C (= M) -N <bond (wherein M represents an O atom or an S atom).

[0007]

By implementing the present invention, taking a tire as an example, the rolling resistance and braking performance on a wet road surface, that is, wet skid resistance, which are important for the recent tire performance described above, are at a high level. A modified unsaturated rubbery polymer is obtained which is harmonized with. The modified unsaturated rubber-like polymer obtained by the production method of the present invention may be used as a rubber component in at least one kind of rubber components for use in tires or the like, or in combination with other rubber components. it can. For example, if the above compound is introduced into a styrene-butadiene copolymer rubber having a bound styrene content of 20 to 25% by weight so that the wet skid resistance can satisfy the required level, the anti-repulsive elasticity can be obtained without impairing the wet skid resistance. Since it can be remarkably improved, a composition which can satisfy the above two characteristics at a high level can be obtained by using the modified unsaturated rubbery polymer alone.
80% of cis-1,4-bond units with high anti-repulsion elasticity
When the above compound is introduced into the above polybutadiene rubber, the modified unsaturated rubbery polymer and wet skid resistance are at a sufficient level, but the rebound resilience is low and the amount of bound styrene is 30% by weight or more. In combination with a butadiene copolymer rubber, a composition that satisfies the above two characteristics at a high level can be obtained.

Further, it is more preferable to combine both the polybutadiene rubber having 80% or more of cis 1,4-bond units and the styrene-butadiene copolymer rubber having 30% by weight of bonded styrene with the above compound introduced. A composition is obtained which can satisfy the two properties at a high level. Further, the modified unsaturated rubbery polymer of the present invention is not particularly required to have high wet skid resistance, and can be used even when high rebound resilience is required.

The modified unsaturated rubber-like polymer of the present invention is usually used as a rubber composition comprising a rubber component and a compounding agent. When the rubber component is contained in the rubber component in an amount of at least 10% by weight, tensile strength and Repulsive elasticity can be improved without impairing wet skid resistance. The unsaturated rubbery polymer in which the compound used in the present invention is introduced into the molecular chain has a carbon-carbon double bond in the polymer chain regardless of the polymerization method (solution polymerization, emulsion polymerization, etc.). And diene-based polymers and copolymers such as butadiene, isoprene, and 1,3-pentadiene, and ring-opening (co) polymers of cycloolefins such as cyclopentene and cyclooctene.

Specifically, polybutadiene rubber, polyisoprene rubber, polychloroprene rubber, styrene-butadiene copolymer rubber (usually, the bound styrene content is 50% by weight).
The following), styrene-isoprene copolymer rubber (usually the amount of bound styrene is 50% by weight or less), butadiene-isoprene copolymer rubber, acrylonitrile-butadiene copolymer rubber, polypentadiene rubber, butadiene-piperylene copolymer rubber, butadiene-propylene. Examples thereof include copolymer rubbers, polypentenamers, polyoctenamers, cyclopentene-dicyclopentadiene ring-opening copolymer rubbers, but are not particularly limited thereto. There is no particular limitation on the microstructure of the diene unit in the polymer.

In the molecule used in the present invention, -C (= M)
The compound having —N <bond (in the formula, M represents an O atom or an S atom) is specifically ε-caprolactam, N
-Methyl-ε-caprolactam, N-acetyl-ε-caprolactam, 2-pyrrolidone, N-methyl-2-pyrrolidone, N-acetyl-2-pyrrolidone, 2-piperidone, N-methyl-2-piperidone, 2-quinolone , N-
Cyclic amides such as methyl-2-quinolone, 2-indolinone, N-methyl-2-indolinone; succinimide,
Maleimide, N-methylmaleimide, N-methylphthalimide, 1,2-cyclohexanedicarboximide, N
Imides such as -methyl-1,2-cyclohexanedicarboximide; urea, N, N'-dimethylurea, N, N,
N ', N'-tetramethylurea, N, N'-dimethyl-
Urea such as ethylene urea; isocyanuric acid, N, N ',
Compounds selected from isocyanuric acids such as N ″ -trimethylisocyanuric acid; amic acids such as methyl carbamate and ethyl N, N-diethylcarbamate (carbamic acids); and their corresponding thio compounds. Particularly preferred compounds. Is a compound in which an alkyl group is bonded to nitrogen.

By reacting these compounds with an alkali metal addition unsaturated rubbery polymer, the polymer having the compound introduced therein is produced by the following method. That is, a method of polymerizing a diene-based polymer using an alkali metal-based catalyst and adding the compound to a living diene-based polymer solution in which the polymerization reaction is completed, unsaturated rubber-like polymer such as diene-based polymer An example is a method in which an alkali metal is added to the rubber in a solution in which is dissolved in an appropriate solvent, and then the compound is added and reacted.

The alkali metal-based catalyst used in the polymerization reaction and addition reaction is a metal itself such as lithium, rubidium or cesium, or a complex with a hydrocarbon compound or a polar compound thereof (for example, n-butyllithium, 2-naphthyllithium, potassium-tetrahydrofuran complex, potassium-diethoxyethane complex, etc.), which may be used as a catalyst for ordinary solution polymerization, and is not particularly limited. In order to achieve the object of the present invention, the amount of the compound having a —C (═M) —N <bond (wherein M represents an O atom or an S atom) in the molecule is the same as the living diene-based compound. One of the catalysts used in polymerizing the coalescence
It is 0.05 to 10 mol per mol, preferably 0.2.
~ 2 moles.

Further, in order to produce the unsaturated rubber-like polymer to which the metal is added by the post-reaction used in the present invention, usually,
The amount of the catalyst used is 0.1 to 2 per 100 grams by weight.
0 mmol, and the amount of the compound used per mol of the catalyst is the same as above. After completion of the reaction, the unsaturated rubber-like polymer into which the compound has been introduced is recovered from the reaction solution by a usual separation method such as addition of a coagulant such as methanol and stripping with steam. The unsaturated rubbery polymer obtained has a molecular chain terminal or in the molecular chain.

[0015]

Embedded image (In the formula, M represents an O atom or an S atom), and the compound is introduced as an atomic group.

Further, in the present invention, even when the reaction with an acid and / or a halogen compound is further performed after the completion of the reaction, a salt or a charge transfer complex of the above-mentioned atomic group whose repulsive elasticity is remarkably improved is introduced. A saturated rubbery polymer is obtained. The site into which the compound is introduced may be the end of the molecular chain or another site, but is preferably the end of the molecular chain, and the end of the molecular chain is a living diene polymer having a dienyl structure and the compound. By using the polymer obtained by the reaction with

The unsaturated rubber-like polymer having the compound introduced into the polymer chain has at least 1 in the rubber component of the rubber composition.
It should be contained in an amount of 0% by weight, preferably 20% by weight or more, more preferably 30% by weight or more. 10% by weight
If it is less than 1, the improvement of repulsive elasticity cannot be expected. When the rubber and other rubbers are used in combination, the other rubbers include emulsion-polymerized styrene-butadiene copolymer rubber, emulsion-polymerized polybutadiene rubber, solution-polymerized (anionic polymerization catalyst, Ziegler type catalyst, etc.) Rubber, styrene-butadiene copolymer rubber, polyisoprene rubber, butadiene-isoprene copolymer rubber, polyalkenamer, etc., and natural rubber are included. Depending on the purpose
One or more of these rubbers are selected and used.

The modified unsaturated rubbery polymer having the compound introduced therein has a Mooney viscosity (ML _{1 + 4} , 100 ° C.) of usually 10 to 200, preferably 20 to 15.
It is a solid rubber at room temperature in the range of 0. Mooney viscosity is 1
If it is less than 0, mechanical properties such as tensile strength are inferior, and if it exceeds 200, miscibility is poor when used in combination with other rubbers, processing operability becomes difficult, and a vulcanized product of the rubber composition obtained. It is not preferable because the mechanical properties of are deteriorated. All or part of the rubber component used in the present invention can be used as an oil-extended rubber. The rubber composition containing the modified unsaturated rubber-like polymer of the present invention is produced by using a mixer such as a roll or Banbury to mix the rubber component and various compounding agents. The various compounding agents used are not particularly limited, as long as they are commonly used in the rubber industry, and those suitable for the purpose of use of the rubber composition may be selected.

Usually, as the vulcanizing system, sulfur, stearic acid, zinc white, various vulcanization accelerators (thiazole type, thiuram type, sulfenamide type etc.) or organic peroxides, etc., and as the reinforcing agent, HAF, Various grades of carbon black such as ISAF, silica, etc., fillers such as calcium carbonate, talc, etc., and other compounding agents such as process oils, processing aids, vulcanization retarders, anti-aging agents, etc. To be done. The type and amount of these compounding agents are selected according to the purpose of use of the rubber composition, and are not particularly limited in the present invention.

The rubber composition containing the modified unsaturated rubbery polymer of the present invention can reconcile the anti-repulsion elasticity and the wet skid resistance at a high level, and is therefore particularly suitable for a rubber material for an automobile tire tread. However, it can also be used for applications such as automobile tires, shoe soles, floor materials, and anti-vibration rubber. A preferred embodiment of using the rubber composition for a tire tread is as follows. (1) Compound-introduced polybutadiene (1,2-bond unit 10 to 90%) / styrene-butadiene copolymer rubber (bound styrene amount 5 to 50% by weight, butadiene unit 1,2
-Bonding units 10-80%) and / or polyisoprene rubber / high cis 1,4-polybutadiene (10-80 / 20)
~ 90/0 to 30% by weight) or (2) the compound-introduced styrene-butadiene copolymer rubber (bound styrene amount 5 to 5).
0% by weight, 1,2-bond units of butadiene units 10-8
0%) / styrene-butadiene copolymer rubber (bound styrene amount 5 to 50% by weight, butadiene unit 1,2-bond unit 10 to 80%) and / or polyisoprene rubber / high cis 1,4-polybutadiene (10 ~ 100/0 ~ 90 /
0-50% by weight)

[0021]

The present invention will be described below in detail with reference to examples.

[Example 1] -C (= M) -N <in the molecule
An example of producing a polybutadiene rubber in which a compound having a bond is introduced will be described below. In a polymerization reactor made of stainless steel with an internal volume of 2 liters, 150 g of 1,3-butadiene and benzene 8
20 g, 0.5 mmol of diethylene glycol dimethyl ether (diglyme) and 1.0 mmol of n-butyllithium (n-hexane solution) were added, and the mixture was stirred at 40 ° C.
Polymerization was carried out for 1 hour. After completion of the polymerization, the compounds shown in Table 1 were added and the reaction was carried out for 5 minutes with stirring. BHT 1.5
The contents of the polymerization reactor were poured into methanol containing wt% to solidify the resulting polymer. The resulting polymer was dried under reduced pressure at 60 ° C. for 24 hours, and then the Mooney viscosity and the 1,2-bond unit amount (by infrared spectroscopy) were measured. The results are also shown in Table 1.

[0023]

[Table 1]

[Reference Example 1] The rubber described in Table 1 was used, and Table 2 was used.
The various compounding agents of the compounding recipe of (1) were kneaded and mixed in a plastic mixer type mixer having a capacity of 250 ml to obtain each rubber compounding composition. A test piece was prepared by press vulcanization at 160 ° C. for 15 to 25 minutes. The strength characteristics are in accordance with JIS K-6301, the anti-repulsion elasticity is 53 ° C. using a Dunlop trypsometer, and the wet skid resistance is 23 ° C. using a portable skid tester (manufactured by Stanley, UK).
It was measured on the road surface of STM E-303-74. The results are shown in Table 3.

[0025]

[Table 2]

[0026]

[Table 3]

Example 2 A production example of a styrene-butadiene copolymer rubber incorporating the compound will be shown. In the same manner as in Production Example 1, 112.5 g of 1,3-butadiene, 37.5 g of styrene, 0.75 g of tetrahydrofuran, and 0.75 mmol of n-butyllithium were placed in a polymerization vessel, and the temperature was 45 ° C.
Was polymerized for 2 hours. After completion of the polymerization, 2.0 mmol of the compound shown in Table 4 was continuously added and reacted. Table 4 shows the properties of the obtained polymer.

[0028]

[Table 4]

[Reference Example 2] Rubber shown in Table 4 and high cis 1,4-polybutadiene (Nipo manufactured by Nippon Zeon Co., Ltd.)
1 BR 1220) and the formulation of Table 2 (however,
Sulfur was 1.8 parts by weight, and N-cyclohexyl-2-benzothiazyl sulfenamide was 1.0 as a vulcanization accelerator.
A rubber compounding composition was prepared according to (parts by weight) and press-vulcanized to prepare a test piece. The same test as in Reference Example 1 was performed. The results are shown in Table 5.

[0030]

[Table 5]

[Example 3] After completion of the polymerization reaction in Example 2,
2 g of 1,3-butadiene was added to continue the polymerization,
A polymer having a butadienyl structure at the terminal of the molecular chain was produced, and after completion of the polymerization, 2.0 mmol of N-methyl-ε-caprolactam was added and reacted. Obtained rubber (Rubber No. 12)
And a styrene-butadiene copolymer rubber (rubber No. 13, 25% by weight of bound styrene, 38% of 1,2-bond units of butadiene units, and weight average molecular weight of 3. 8 × 10 ⁵ ) was used and mixed in the ratios shown in Table 6, and a vulcanized product was obtained with the same formulation as in Reference Example 2. The test results for these vulcanizates are shown in Table 6.

[0032]

[Table 6]

[0033]

According to the present invention, there is provided a method for producing a modified unsaturated rubber-like polymer capable of giving a vulcanized rubber having improved tensile strength and rebound resilience.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Tetsuo Oyama 41-13 Enokioka, Midori-ku, Yokohama-shi, Kanagawa

Claims (2)

[Claims] 1. A solid unsaturated rubbery polymer to which an alkali metal is added, and cyclic amides; succinimide, maleimide, N-methylmaleimide, N-methylphthalimide, 1,2-cyclohexanedicarboximide, and N.
One imide selected from the group consisting of -methyl-1,2-cyclohexanedicarboximide; amic acids; urea, N, N, N ', N'-tetramethylurea, and N,
One type of ureas selected from the group consisting of N'-dimethyl-ethyleneurea; isocyanuric acids; and -C (= M) -N <in the molecule selected from the group consisting of thio compounds corresponding to these compounds. A method for producing a modified unsaturated rubbery polymer, which comprises reacting with a compound having a bond (wherein M represents an O atom or an S atom). 2. The following formula at the molecular chain end or in the molecular chain: The method for producing a modified unsaturated rubber-like polymer according to claim 1, wherein an atomic group represented by the formula (wherein M represents an O atom or an S atom) is introduced.