JPS6367815B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a high hardness rubber composition having extremely excellent kneading processability and roll processability, reduced specific gravity, and excellent acid resistance. In many industrial fields including the vehicle field, energy savings and productivity improvements are achieved through weight reduction.
For the purpose of improving performance, reducing costs, durability, and corrosion resistance, a switch from metals to high-hardness rubber compositions containing ethylene-propylene rubber as a main component is underway. Also, focusing on the excellent performance of the high hardness rubber composition, new industrial applications are being investigated. Conventionally, in order to obtain a high hardness rubber composition, methods such as highly filling fillers such as carbon black and silica and methods such as reducing extender oil have been carried out, but although they are not sufficient, it is difficult to obtain the desired high hardness composition. was obtained. However, on the other hand, it has problems such as poor processability and productivity, high specific gravity, and deterioration of rubber properties, which greatly hinders the industrial use of high-hardness rubber compositions. . In addition, ethylene-propylene rubber, which has excellent weather and water resistance, has been used in solar hoses, water hoses, waterproof sheets, etc.
In recent years, there has been a demand for ethylene-propylene rubber to have excellent acid resistance in order to withstand even more severe usage conditions. An object of the present invention is to provide a high hardness rubber composition that has good kneading processability and roll processability, has a light specific gravity, and has excellent acid resistance. The high hardness rubber composition of the present invention contains ethylene-α-olefin copolymer rubber and/or ethylene-α-olefin non-conjugated diene copolymer rubber and/or ethylene-α-olefin non-conjugated diene copolymer rubber (A). Thermoplastic resin (B) 5 having an intrinsic viscosity of 0.2 to 1.5 (dl/g) obtained by copolymerizing a monomer containing an aromatic vinyl compound as an essential component in the presence of a conjugated diene copolymer rubber ~80 parts by weight and ethylene-α-olefin copolymer rubber and/or ethylene-α
-Olefin-nonconjugated diene copolymer It is characterized by containing 10 to 80 parts by weight of a thermoplastic resin (C) obtained by copolymerizing a vinyl chloride monomer in the presence of a rubber. In the present invention, the ethylene-α-olefin-nonconjugated diene copolymer rubber (A) is not particularly limited, but examples of α-olefins include 1-butene, 2-butene, propylene, etc. Propylene is particularly preferred. Examples of the non-conjugated diene include ethylidenenorbornene, 4,7,8,9-tetrahydroindene, dicyclopentadiene, 1,4-hexadiene, propenylnorbornene, methylidenenorbornene, and the like. The base rubber of the thermoplastic resin (B) is ethylene-α-olefin copolymer rubber (hereinafter referred to as EPM) and/or ethylene-α-olefin-nonconjugated diene copolymer rubber (hereinafter referred to as EPDM). ), and the α-olefins and nonconjugated dienes are those explained in (A) above. The copolymer rubber is preferably EPDM. The aromatic vinyl monomer used in graft polymerization is not particularly limited, but examples thereof include styrene, α-methylstyrene, p-methylstyrene, vinyltoluene, and the halogen-substituted styrene. are used singly or in combination of two or more. Preferably, styrene or α-methylstyrene is used. The aromatic vinyl monomer component in the resin component of the thermoplastic resin (B) is preferably 30% by weight or more, particularly preferably 50% by weight or more. Monomers that can be used in the copolymer along with the aromatic vinyl monomer are shown below. Examples of vinyl cyanide monomers include acrylonitrile and methacrylonitrile. These may be used alone or in combination of two or more. As a (meth)acrylic acid ester monomer,
There are alkyl acrylates, alkyl methacrylates, and esters of ethylenically unsaturated carboxylic acids and hydroxyalkyl. Acrylic acrylates include, for example, methyl acrylate, ethyl acrylate, butyl acrylate, and alkyl methacrylates include, for example, methyl methacrylate, ethyl methacrylate. etc. Examples of the hydroxyalkyl ester of ethylenically unsaturated carboxylic acid include β-hydroxyethyl acrylate and β-hydroxyethyl methacrylate. These are one or two types
More than one species can be used, but methyl methacrylate is preferred. Other copolymerizable monomers include maleic anhydride, itaconic anhydride, acrylic acid, methacrylic acid, acrylamide, divinylbenzene, trimethylolpropane, and triacrylate.
These can be used alone or in combination of two or more. As the monomer component in the thermoplastic resin (B), the above-mentioned monomers can be used in addition to the aromatic vinyl monomer. These monomers can be used alone or in combination of two or more. Preferred monomer combinations include aromatic vinyl monomer-vinyl cyanide monomer, aromatic vinyl monomer-(meth)acrylic acid ester monomer, and aromatic vinyl monomer-vinyl cyanide. Monomer - (meth)acrylic acid ester monomer. In order to achieve the purpose of the present invention, EPM and EPDM in the thermoplastic resin (B) play a major role. That is, by using EPM and EPDM, a high hardness rubber composition with excellent roll processability and extrusion processability and excellent performance can be obtained.
If a diene rubber is used instead of EPDM, or if a thermoplastic resin without a rubbery polymer is used, the high hardness rubber composition targeted by the present invention cannot be obtained. Thermoplastic resin (B) for 100 parts by weight of ethylene-α-olefin-nonconjugated diene copolymer rubber (A)
is used in an amount of 5 to 80 parts by weight, preferably 10 to 80 parts by weight. If the thermoplastic resin (B) exceeds the range of the present invention, the desired effects of the present invention cannot be obtained.
That is, if the blending amount of the thermoplastic resin (B) is less than 5 parts by weight, a high hardness rubber composition with excellent processability cannot be obtained, whereas if it exceeds 80 parts by weight, excellent processability cannot be obtained. I can't. In addition, preferred content of the rubbery polymer of the thermoplastic resin to obtain the high hardness rubber composition of the present invention, grafting rate *, *(grafting rate = weight of resin component grafted to rubbery polymer / rubbery polymer Combined weight x 100%) Intrinsic viscosity of methyl ethyl ketone soluble portion ([η] 30
°C MEK) is shown below. The content of the rubbery polymer is preferably 5 to 70% by weight, particularly preferably 5 to 60% by weight, and even more preferably 10 to 50% by weight. Grafting rate is 5-200%, preferably 21-120
%, more preferably 25 to 100%. The intrinsic viscosity is 0.2 to 1.5 (dl/g), particularly preferably 0.25 to 1.1 (dl/g). The intrinsic viscosity is
If it is less than 0.2 (dl/g), a high hardness rubber composition cannot be obtained, while if it exceeds 1.5 (dl/g), excellent processability cannot be obtained. The method for producing the thermoplastic resin described above is not particularly limited, and includes emulsion polymerization method,
It can be produced by a suspension polymerization method, a solution polymerization method, a bulk polymerization method, or a combination of these polymerization methods. Next, as a resin-forming component of the thermoplastic resin (C), vinyl chloride monomer or other copolymerizable vinyl monomers can be used as long as the object of the present invention is not impaired. A method for producing the thermoplastic resin (C) is disclosed, for example, in Japanese Patent Application Laid-open Nos. 50-33286 and 50-153089. The base rubber content in the thermoplastic resin (C) is preferably 10 to 50% by weight, particularly preferably 20 to 50% by weight.
50% by weight. For 100 parts by weight of ethylene-α-olefin-nonconjugated diene copolymer rubber (A), the thermoplastic resin (C) is 10 to 80 parts by weight, preferably 20 to 80 parts by weight.
Use parts by weight. If the amount of the thermoplastic resin (C) used exceeds the above range, the effects of the present invention cannot be obtained. That is, if the amount of the thermoplastic resin composition (C) is less than 10 parts by weight, a high hardness rubber composition with excellent processability and acid resistance cannot be obtained, while if it exceeds 80 parts by weight, excellent processability will not be obtained. I can't get it. As a method for obtaining the high hardness rubber composition of the present invention, for example, using a normal rubber kneading machine, that is, a Banbury mixer, an open roll,
It is obtained by kneading EPDM, a thermoplastic resin, and other compounding agents, and then adding a commonly used vulcanizing agent to perform vulcanization. The high hardness rubber composition of the present invention contains various additives, vulcanizing agents, rubbery polymers, resins, anti-aging agents, lubricants, plasticizers, ultraviolet absorbers, and blowing agents, depending on the required performance. etc. may be added. Other known rubbery polymers and resins that can be added include, for example, polybutadiene, butadiene-styrene copolymers, acrylic rubber, styrene-copolymers,
Butadiene block polymer, styrene-butadiene-styrene radial teleblock polymer, polypropylene, butadiene-acrylonitrile copolymer, polyvinyl chloride, polycarbonate,
Examples include PET, PBT, polyacetal, polyamide, epoxy resin, polyvinylidene fluoride, polysulfone, ethylene-vinyl acetate copolymer, polyisoprene, natural rubber, chlorinated butyl rubber, chlorinated polyethylene, PPS resin, polyether ether ketone, etc. . The high-hardness rubber composition of the present invention has excellent performance by combining high hardness and excellent processability, which are characteristics of resins, and rubber elasticity, which is characteristics of rubber, and is light, durable, and durable. Because of its corrosive properties, metals used in various industrial fields, such as vehicles, ships, architecture, civil engineering, electrical fields, sporting goods, furniture, medical equipment, etc.
It can also be used as a substitute for other materials, and can also be used in new industrial applications. For example, car bumpers, front grills, window frames,
It can be used as an exterior material for the body.
Furthermore, by forming the composition into a foam, it is possible to obtain a composition that is excellent in durability, appearance, strength, shielding performance, and sound insulation performance as various sealing materials. Furthermore, by adding a lubricant such as molybdenum disulfide, higher fatty acid amide, silicone oil, etc., it is possible to obtain a composition with a significantly small dynamic mass coefficient and excellent snappy properties for use in automobile wipers and glass runs. Hereinafter, the present invention will be specifically explained using Examples and Comparative Examples. Example 1 An example of a method for producing the thermoplastic resin (B) used in the rubber composition of the present invention is shown. (ethylene-propylene-
Manufacturing method of non-conjugated diene copolymer/styrene/acrylonitrile copolymer) After purging the interior of a stainless steel reactor equipped with a paddle-type stirring blade with nitrogen, the iodine value was 15, the Mooney viscosity was 65, and the propylene content was 43% by weight. , 24 parts of EPDM (JSR EP24 manufactured by Japan Synthetic Rubber Co., Ltd.) containing ethylidenenorbornene as a diene component, styrene
Add 56 parts of acrylonitrile, 20 parts of acrylonitrile, and 100 parts of toluene, and stir at 50°C until the rubber is completely dissolved. After adding 0.2 part of carbonate and 0.1 part of dicumyl peroxide, the temperature was raised to 80℃.
for 3 hours, then raise the temperature to 100℃ for 3 hours, and then
The temperature was raised to 125°C and the polymerization reaction was carried out for 3 hours, for a total of 9 hours. After removing unreacted monomers and solvent by steam distillation, the mixture was crushed and dried to obtain a polymer. The graft ratio of the thermoplastic resin (B) thus obtained was 5%, and the [η] MEK at 30°C was 0.50. The above graft ratio was determined as follows. the above
Approximately 1 g of (B) is collected and accurately weighed, and the amount of rubbery polymer in this sample is defined as _W1 . The amount of rubbery polymer is determined from the amount of rubbery polymer charged during polymerization and the monomer conversion rate. Next, methyl ethyl ketone (MEK) 20c.c.
was added, shaken at room temperature for 5 hours, and then centrifuged at 20,000 rpm for 60 minutes.
Separate MEK into soluble and insoluble components, dry the insoluble components, and weigh accurately to obtain _W2 . Next, the grafting rate is determined using the following formula. Grafting rate=W ₂ −W ₁ /W ₁ ×100 The above [η] 30°C MEK was determined as follows. Methanol was added to the above MEK soluble content to recover the polymer content, and this polymer was measured at a temperature of 30°C using MEK as a solvent using an Ubbelod viscometer. Examples 2, 3, 4 Table 1 shows the formulation and test results of Examples 2, 3, and 4. The thermoplastic resin (B) shown in Table 1 is the composition produced in Example 1, and the thermoplastic resin (C) is the ethylene-propylene composition.
It consists of 35% by weight of ethylidene norbornene copolymer rubber component and 65% by weight of vinyl chloride resin component. All formulations are in parts by weight. Vulcanization was carried out using steam press vulcanization at 160°C for 25 minutes. The tensile test was based on JIS K 6301. The kneading processability was determined by visually observing the cohesion of the rubber and the surface texture of the rubber after kneading. Roll processability was determined by visual observation of roll wrapping properties and rubber surface texture. Acid resistance is determined by measuring the effective chlorine concentration of a vulcanized rubber sample piece.
60℃ x 1000ppm sodium hypochlorite aqueous solution
Quality was determined by the appearance of the rubber after 720 hours of immersion.

【table】

[Table] Comparative Examples 1, 2, 3, 4, 5, 6 Table-2 shows Comparative Example-1, Comparative Example-2, Comparative Example-
3. The formulations and test results of Comparative Example-4, Comparative Example-5, and Comparative Example-6 are shown. EP21, EP51, vulcanizing agents, and compounding agents listed in Table 2 are the same as those used in the examples, and ABS
The resin was JSR ABS 10 manufactured by Japan Synthetic Rubber Co., Ltd., and the polystyrene resin was Toporex 550 manufactured by Mitsui Toatsu Chemical Co., Ltd. All formulations are in parts by weight. The vulcanization method, tensile test, kneading processability, roll processability and acid resistance measurements were carried out in the same manner as in the examples. Comparative Example 1 is an example in which the thermoplastic resin (B) constituting the rubber composition of the present invention is excluded and the amount of carbon black filled is increased, and Comparative Example 2 is an example in which the thermoplastic resin (C) constituting the rubber composition of the present invention is increased. This is an example in which the upper limit was exceeded to achieve the effect of 1. Comparative Example-3 and Comparative Example-4 are examples in which ABS resin and polystyrene resin were blended in place of the thermoplastic resin (B). Comparative Example 5 is an example in which the thermoplastic resin (C) constituting the rubber composition of the present invention was removed and the amount of carbon black filled was increased.
Furthermore, Comparative Example 6 is an example in which a rubbery polymer outside the scope of the present invention was blended. An example of a method for producing this rubbery polymer will be shown. (Production method of ethylene-propylene non-conjugated diene copolymer/styrene/acrylonitrile copolymer) EPDA containing ethylidene norbornene as the diene component (manufactured by Japan Synthetic Rubber Co., Ltd.) with an iodine value of 15, a Mooney viscosity of 65, and a propylene content of 43% by weight. J.S.R.
EP 24) in 1000 parts by weight of a 10% n-hexane solution,
Add 140 parts by weight of a 15% aqueous solution of disproportionated potassium rosinate, stir with a homomixer, and emulsify. The solvent is then completely removed by steam distillation.
A latex with a particle size of 1000-10000 Å was obtained. This latex has a rubber solid content concentration of 10% and is used as a pace polymer. Composition A; EP24 latex (rubber solids concentration 10%)
900 parts by weight Disproportionated potassium rosinate 15% aqueous solution 5 Sodium hydroxide 0.04 parts by weight Styrene 10 Acrylonitrile 5.2 Ferrous sulfate 0.008 Sodium pyrophosphate 0.4 Dextrose 0.5 Cumene hydroperoxide 0.06 Water 20 Composition B: Styrene 7 Acrylonitrile 3 Balanced potassium rosinate 15% aqueous solution 11 Sodium hydroxide 0.14 Cumene hydroperoxide 0.14 Water 20 According to the above polymerization recipe, composition A was first charged into a flask and polymerized at a polymerization temperature of 70°C for 1 hour under a nitrogen stream. Composition B was then continuously added at a polymerization temperature of 70° C. over a period of 2 hours to polymerize substantially all of the vinyl monomer. Sulfuric acid is added to the polymer latex thus obtained, the mixture is coagulated by heating, washed with water, dehydrated, and dried to obtain a polymer. The thus obtained polymer had a graft ratio of 8%, and was a rubbery graft polymer with [η] MEK at 30°C of 0.18. Note that the above-mentioned graft ratio and [η] 30°C MEK were determined by the same method as in Example 1. In Comparative Example 5, a high hardness composition cannot be obtained.

【table】

Claims (1)

[Claims] 1 100 parts by weight of ethylene-α-olefin-nonconjugated diene copolymer rubber (A), ethylene-α-olefin and/or ethylene-α-olefin
5 to 80 weight thermoplastic resin (B) with an intrinsic viscosity of 0.2 to 1.5 dl/g obtained by copolymerizing a monomer containing an aromatic vinyl compound as an essential component in the presence of a nonconjugated diene copolymer rubber and 10 to 80 parts by weight of a thermoplastic resin (C) obtained by copolymerizing vinyl chloride in the presence of ethylene-α-olefin and/or ethylene-α-olefin-nonconjugated diene copolymer rubber. A high hardness rubber composition characterized by: