JP2010053212A - Heat shrinkable rubber composition and molded product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rubber composition easily heat-shrinkable at a temperature ≤100°C, and a molded product comprising the rubber composition. <P>SOLUTION: The heat shrinkable rubber composition comprises 3 to 100 pts.wt. of a side-chain crystalline polymer (B) based on 100 pts.wt. of a rubber component (A), a softening agent (C), a filler (D), and a vulcanizing agent (E). There is also provided a molded product comprising the rubber composition. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a rubber composition that can be easily heat-shrinked at a temperature of 100 ° C. or less, and a molded article containing the composition.

Conventionally, heat-shrinkable (a kind of shape memory) film, sheet and tube used for sealing of articles, packaging, coating of electric wires and steel pipes, coating of glass bottles, etc. Was used. A heat-shrinkable molded product made of polyvinyl chloride is inferior in durability and has drawbacks such as plasticizer exudation. Therefore, heat-shrinkable molded products such as polyethylene and polypropylene are used in some fields. However, conventional heat-shrinkable molded articles such as polyethylene have limited applications because of their high heat shrinkage (recovery) temperature and lack of rubber elasticity.
In addition, heating for heat shrinking requires high-temperature heating devices such as gas torches, burners, and dryers, and appliances, and mass production requires complicated high-temperature generators, causing problems in terms of cost and workability. there were. In addition, there are problems such as adverse effects on rubber materials due to exposure to high temperatures, danger to workers, and soaring energy costs associated with heating.

Patent Document 1 discloses an invention related to a film, sheet, or tube-shaped heat-shrinkable molded body in which polypropylene is finely dispersed in ethylene / α-olefin / polyene random copolymer rubber. The heat-shrinkable vulcanized rubber tube obtained from this invention had sufficient rubber elasticity. However, in order to obtain a high shrinkage rate of 50% or more in a short time, the shrinkage of 160 ° C. or more is required. In some cases, the resin cannot be used for a resin product requiring a temperature and having a relatively low melting point such as polyvinyl chloride or polyethylene.
It is widely known that a polyethylene tube is mixed with ethylene propylene diene copolymer rubber (EPDM) to produce a heat shrinkable tube, but a shrinkage temperature of 125 ° C. or higher is required.
For example, Patent Document 2 discloses a method of chemically cross-linking a tube body made of polyvinyl chloride mixed with a cross-linking agent to obtain a heat-shrinkable tube, but there are problems in tightening stress and sealing performance. It was.

  Patent Document 3 proposes a thermoplastic elastomer composition in which 5 to 70 parts by weight of a resin having a melting point of 50 to 120 ° C. is added to 100 parts by weight of a crosslinked particle rubber / olefin resin blend. However, there is a problem in terms of cost because it requires equipment for producing crosslinked particle rubber and dynamic heat treatment at high temperatures. In addition, thermoplastic elastomers have a problem in compression set as compared with vulcanized rubber.

Patent Document 4 discloses a heat-shrinkable thermoplastic elastomer obtained by dynamic vulcanization of an ethylene / vinyl acetate copolymer and a butyl rubber mixture. However, the heat-shrinkable tube has a large residual elongation and has a sufficient heat resistance. The shrinkage rate is not obtained.

JP-A-9-309986 JP-A-57-187214 Japanese Patent No. 3853230 Japanese Examined Patent Publication No. 6-62816

  In order to solve the above problems, the object of the present invention is that there is little natural recovery during storage, recovery is possible at 100 ° C. or less, and after recovery, the mechanical strength, weather resistance, heat resistance and rubber elasticity are excellent. Heat-shrinkable rubber composition and molded body capable of obtaining a sulfur molded body, in particular, a tube-shaped, rod-shaped, film-shaped or sheet-shaped molded body, resin tube joint, electric wire bundling, power cable joint cover, terminal cover, automobile Another object of the present invention is to provide a heat-shrinkable rubber composition applicable to various protective covers, steel pipe linings, fume pipe linings, and the like, and a vulcanized molded product obtained by vulcanization molding from the heat-shrinkable composition.

As a result of intensive studies, the present inventors have found that a heat-shrinkable rubber composition containing 3 to 100 parts by weight of a side chain crystalline polymer (B) at 100 ° C. or lower with respect to 100 parts by weight of the rubber component (A). The present invention has been completed by finding that it has little natural recovery during storage and can be recovered at 100 ° C. or lower, and has excellent mechanical strength, weather resistance, and heat resistance after recovery.
More specifically, the present invention provides the following heat-shrinkable rubber composition and molded article.

(1) 3 to 100 parts by weight of side chain crystalline polymer (B), softener (C), filler (D) and vulcanizing agent (E) with respect to 100 parts by weight of rubber component (A) A heat-shrinkable rubber composition.
(2) The heat-shrinkable rubber composition according to (1), wherein the rubber component (A) is an ethylene / α-olefin / non-conjugated polyene copolymer rubber.
(3) The ethylene / α-olefin / non-conjugated polyene copolymer rubber is an ethylene / propylene / dicyclopentadiene copolymer rubber, ethylene / propylene / 5-ethylidene-2-norbornene copolymer rubber, ethylene / propylene 1,4-hexadiene copolymer rubber, ethylene / 1-butene / 1,4-hexadiene copolymer rubber, ethylene / propylene / 5-vinyl-2-norbornene copolymer rubber (1) to (2 The heat-shrinkable rubber composition according to any one of 1).
(4) The heat-shrinkable rubber composition according to any one of (1) to (3), wherein the side chain crystalline polymer (B) has a melting point of 100 ° C. or lower.
(5) The heat-shrinkable rubber composition according to any one of (1) to (4), wherein the side chain crystalline polymer (B) has a melting point in the range of 30 ° C to 80 ° C.
(6) The heat-shrinkable rubber composition according to any one of (1) to (5), wherein the side chain crystalline polymer (B) is mainly composed of an α-olefin unit having 10 or more carbon atoms.
(7) The side chain crystalline polymer (B) is an α-olefin homopolymer and / or copolymer mainly composed of an α-olefin unit having 10 or more carbon atoms. The heat-shrink rubber composition according to any one of the above.
(8) A vulcanized molded product obtained by vulcanization molding from the heat-shrinkable rubber composition according to any one of (1) to (7).
(9) The vulcanized molded product according to (8), which is used as a heat shrinkable tube.
(10) Busbar insulation (generator, vehicle rotating machine), motor, transformer, switching regulator insulation (TV, VTR) insulation of various sensors (electronic jar, hot air heater, stove) terminal insulation of various heaters The heat-shrinkable tube used for terminal insulation (dryer, precision equipment, robot, automobile, physics and chemistry equipment) of various harnesses (seeds, cartridges, throwing heaters).
(11) The said heat shrinkable tube used for the joint of the joint part of a metal pipe and / or a nonmetal pipe.
(12) Wire / cable wiring connections and terminal protection, for mechanical applications, automotive hoses, pipe covers and roller covers, waterproof covers for sewer pipe joints, anticorrosion for steel pipes, grips, anti-slip on handrails, electric lights, fluorescent light The heat-shrinkable tube used for a light, a cover for preventing damage to various containers, and an adhesive label that does not use an adhesive for recycling containers.

The vulcanized molded product obtained from the heat-shrinkable rubber composition according to the present invention is excellent in rubber elasticity and has shape memory properties and shape recoverability that are indicators of heat-shrinkability. Even if deformation occurs temporarily thereafter, it can be easily restored to its original shape and is suitable as a heat-shrinkable tube. Furthermore, heat shrinks easily at temperatures below 100 ° C, making it possible to heat shrink in environments such as hot water or direct sunlight, and using gas burners, etc. under high altitude work (insulation of wires and cables) The effects of avoiding the dangers and environmental and safety effects are enormous.
The heat-shrinkable rubber composition of the present invention comprises busbar insulation (generator, vehicle rotating machine), motor, transformer, insulation of switching regulator outlet (TV, VTR), insulation of various sensors (electronic jar, hot air heater, Stove) Terminal insulation of various heaters (seeds, cartridges, throwing heaters), terminal insulation of various harnesses (dryers, precision equipment, robots, automobiles, physics and chemistry equipment), heat shrink tubes, metal pipes and non-metal pipes Heat-shrinkable tubes used for joints in joints, wire / cable connections and terminal protection, automotive hoses, pipe covers and roller covers, waterproof covers for sewer pipe joints, corrosion protection for steel pipes, grips, Non-slip railings, electric lamps, fluorescent lamps, covers for preventing damage to various containers, and recycling containers Agents contact the label heat-shrinkable tube such as a wide range of use for use in using no is expected.

The heat-shrinkable rubber composition according to the present invention comprises the rubber component (A), the side chain crystalline polymer (B), the softening agent (C), the filler (D), and the crosslinking agent (E) as essential components. In addition, various compounding agents are added and mixed as necessary. Next, each component will be described in detail.
The rubber component (A) that can be used in the present invention may be natural rubber, synthetic rubber, or a mixture thereof. Examples of synthetic rubbers include ethylene / α-olefin / non-conjugated polyene copolymer rubber, styrene / butadiene rubber, acrylonitrile / butadiene rubber, chloroprene rubber, acrylic rubber, hydrogenated NBR, hydrin rubber, ethylene / acrylic rubber, chlorosulfone. And polyethylene rubber, silicone rubber, fluorine rubber and the like.

  Among these, a particularly preferable synthetic rubber is an ethylene / α-olefin / non-conjugated polyene copolymer rubber. Here, the α-olefin is an olefin having 3 to 20 carbon atoms, and examples thereof include propylene, 1-butene, 4-methyl-1-pentene, 1-hexene, 1-octene and 1-decene. In particular, propylene and 1-butene are preferably used. The molar ratio of ethylene to α-olefin (ethylene / α-olefin) in the copolymer is in the range of 60/40 to 85/15, preferably 65/35 to 80/20.

As the nonconjugated polyene, a cyclic or chain nonconjugated polyene is used. Examples of the cyclic non-conjugated polyene include 5-ethylidene-2-norbornene, dicyclopentadiene, 5-vinyl-2-norbornene, norbornadiene, and methyltetrahydroindene. Examples of the chain non-conjugated polyene include 1, Examples include 4-hexadiene, 7-methyl-1,6-octadiene, 8-methyl-4-ethylidene-1,7-nonadiene, and 4-ethylidene-1,7-undecadiene. These non-conjugated polyenes may be a copolymer component alone or in combination of two or more.
Preferred ethylene / α-olefin / non-conjugated polyene copolymer rubbers in combination with the above monomers include ethylene / propylene / dicyclopentadiene copolymer rubbers, ethylene / propylene / 5-ethylidene-2-norbornene copolymer rubbers. , Ethylene / propylene / 1,4-hexadiene copolymer rubber, ethylene / 1-butene / 1,4-hexadiene copolymer rubber, ethylene / propylene / 5-vinyl-2-norbornene copolymer rubber, etc. Can do.

  The iodine value which shows the nonconjugated polyene content in this copolymer is 1-40, Preferably it is 2-35, More preferably, it is 3-30. The intrinsic viscosity [η] of the copolymer rubber is a value measured at 135 ° C. in decalin of 0.8 to 4.0, preferably 1.0 to 3.5, more preferably 1.1. It is in the range of -3.0 (dl / g). When the iodine value and the intrinsic viscosity are in the above ranges, a vulcanized rubber molded article having excellent rubber elasticity can be produced.

A method for producing an ethylene / α-olefin / non-conjugated polyene copolymer rubber having such a structure is already known. For example, “Polymer Production Process (published by Industrial Research Council, P.309-330)” Can be produced by the method described in the above.
Next, the side chain crystalline polymer (B) of the present invention preferably has a melting point of 100 ° C. or lower. The side chain crystalline polymer (B) is a kind of graft polymer, and a part or the whole of the side chain can form a crystal. As a method for obtaining the side chain crystalline polymer (B), (co) polymerization mainly composed of higher α-olefin, (co) polymerization of monomers mainly composed of long chain alkyl (meth) acrylate, long And (co) polymerization of monomers mainly composed of chain alkylethylene oxide. Moreover, the method of graft-adding a higher fatty acid to polyvinyl alcohol is also mentioned.

  Particularly preferable examples of the side chain crystalline polymer (B) used in the present invention include crystalline olefin homopolymers and / or copolymers mainly composed of α-olefin units having 10 or more carbon atoms. That is, a higher α-olefin homopolymer having 10 or more carbon atoms, or two or more of these α-olefins, and further one or more higher α-olefins having 10 or more carbon atoms and one or more other olefins are copolymerized. It is a copolymer obtained by doing this.

As the α-olefin having 10 or more carbon atoms, those having 10 to 35 carbon atoms are preferable. For example, 1-decene, 1-undecene, 1-dodecene, 1-eicosene and the like can be mentioned.
When an α-olefin having 10 or more carbon atoms is used, the obtained α-olefin homopolymer or copolymer has high crystallinity, which is preferable for obtaining the heat-shrinkable rubber composition of the present invention.
Moreover, when an α-olefin having 35 or less carbon atoms is used, the polymerization yield of the obtained α-olefin homopolymer or copolymer is high, which is preferable in production.

As described above, the crystalline olefin homopolymer and / or copolymer may contain an olefin unit other than the higher α-olefin having 10 or more carbon atoms, but the ratio of the higher α-olefin unit having 10 or more carbon atoms. Is preferably 75 mol% or more, more preferably 85 mol% or more, still more preferably 90 mol% or more.
When this ratio is large, high crystallinity is obtained, which is preferable for use in the heat-shrinkable rubber composition of the present invention.
The side chain crystalline polymer (B) of the present invention preferably has a polystyrene-equivalent weight average molecular weight of 1,000 to 10,000,000 measured by gel permeation chromatography (GPC).
More preferably, it is 3,000-1,000,000, More preferably, it is 10,000-100,000.
When the weight average molecular weight is 1,000 or more, the strength of the resulting heat-shrinkable rubber composition is high, and when it is 10,000,000 or less, the processability of the obtained heat-shrinkable rubber composition is excellent. is there.

The side chain crystalline polymer (B) of the present invention preferably has a melting point of 30 ° C. to 100 ° C. determined from a melting endotherm curve obtained using a differential scanning calorimeter (DSC).
More preferably, it is 30 degreeC-80 degreeC, More preferably, it is 40 degreeC-70 degreeC. The side chain crystalline polymer (B) of the present invention preferably has a heat of fusion of 30 J / g or more determined from a melting endothermic curve obtained using a differential scanning calorimeter (DSC).
More preferably, it is 50 J / g or more, More preferably, it is 60 J / g or more.
This is because when the heat of fusion is 30 J / g or more, the obtained heat-shrinkable rubber composition exhibits remarkable softening with the melting point of the side chain crystalline polymer (B) as a boundary.

  The amount of the side chain crystalline polymer (B) of the present invention is 3 to 100 parts by weight, preferably 5 to 80 parts by weight, more preferably 10 parts per 100 parts by weight of the rubber component (A). Parts by weight to 50 parts by weight. When the blending amount of both is in this range, a heat-shrinkable rubber composition having an excellent balance between heat recovery from deformation and rubber elasticity can be obtained.

  The softener (C) of the present invention is compatible with the rubber component (A) and the side chain crystalline polymer (B), and improves the processability of the heat-shrinkable rubber composition. The following substances can be used as examples of such softeners.

  Petroleum softeners such as naphthenic process oil, aromatic process oil, lubricating oil, paraffin, liquid paraffin, petroleum asphalt, and petroleum jelly, and softening softening such as cold tar and cold tar bitch Agents, fatty oil softeners such as castor oil, rapeseed oil, soybean oil, coconut oil, waxes such as beeswax, carnauba wax, lanolin, ricinoleic acid, palmitic acid, stearic acid, barium stearate, calcium stearate, etc. Fatty acids or their metal salts

  Naphthenic acid or its metal soap, pine oil, rosin or its derivatives, terpene resin, petroleum resin, coumarone indene resin, synthetic polymer materials such as atactic polypropylene, dioctyl phthalate, dioctyl adipate, dioctyl acetate Ester plasticizers such as buckets, carbonate plasticizers such as diisododecyl carbonate, microcrystalline wax, sub (factory), liquid polybutadiene, modified liquid polybutadiene, liquid thiocol, hydrocarbon-based synthesis Lubricating oil etc.

  Of these, mineral oil softeners are preferably used in the present invention, and aromatic mineral oils exemplified by aromatic process oils are particularly desirable. These softeners are sold under trade names such as Diana Process AC-460 (product of Idemitsu Kosan Co., Ltd.), Diana Process AC-12 (product of Idemitsu Kosan Co., Ltd.), Esso Process Oil 110 (product of Esso Oil Co., Ltd.). Can be used for invention. These softeners (C) are 5 parts by weight to 300 parts by weight, preferably 10 parts by weight to 200 parts by weight, and more preferably 10 parts by weight to 100 parts by weight with respect to 100 parts by weight of the rubber component (A). is there. If it is less than 5 parts by weight, the compatibility between the rubber component (A) and the side chain crystalline resin (B) becomes insufficient, and if it exceeds 300 parts by weight, the kneading processability is hindered.

The filler (D) of the present invention enhances the mechanical strength and kneading processability of the heat-shrinkable rubber composition. For example, carbon black, heavy calcium carbonate, corn flour, light calcium carbonate, ultrafine activated carbonic acid Calcium, special calcium carbonate, basic magnesium carbonate, kaolin clay, calcined clay, pyroflight clay, silanized clay, natural silicic acid, synthetic silicic anhydride, synthetic hydrous silicic acid, synthetic calcium silicate, synthetic magnesium silicate, synthetic Aluminum silicate, magnesium carbonate, aluminum hydroxide, magnesium hydroxide, magnesium oxide, aluminum oxide, ferrite, kaolin, sericite, talc, fine talc, wollastonite, zeolite, zonotonite, mica, asbestos, PMF (Processed Mineral Fiber: Processed mineral fiber), se Olite, potassium titanate, elastadite, gypsum fiber, glass balun, silica balun, hydrotalcite, fly ash balun, shirasu balun, carbon balun, phenolic resin, urea resin, styrene resin, saran resin, etc. organic balun, alumina, sulfuric acid Barium, aluminum sulfate, calcium sulfate, molybdenum disulfide, graphite, glass fiber (chopped strand, roving, milled glass fiber, glass flake), cut fiber, lock fiber, microfiber, carbonate fiber, aromatic polyamide fiber, potassium titanate Examples thereof include fiber, recycled rubber, rubber powder, ebonite powder, shellac, and wood powder. These fillers can be used alone or in admixture of two or more.
These fillers (D) are 5 to 300 parts by weight, preferably 10 to 200 parts by weight, and more preferably 10 to 100 parts by weight with respect to 100 parts by weight of the rubber component (A). . If it is less than 5 parts by weight, the mechanical strength of the resulting heat-shrinkable rubber composition is insufficient, and if it exceeds 300 parts by weight, the kneading process is hindered.

  As the vulcanizing agent (E) of the present invention, depending on the type of the rubber component (A), a sulfur vulcanizing agent, an organic peroxide, a quinoid vulcanizing agent, a resin vulcanizing agent, a metal oxide vulcanizing agent, A sulfur organic compound, an amine vulcanizing agent, a triazine vulcanizing agent, a polyol vulcanizing agent, a metal soap vulcanizing agent, a maleimide vulcanizing agent, a hydrosilylation reaction crosslinking agent, and the like are appropriately selected and used.

  Examples of the sulfur vulcanizing agent include powdered sulfur, sulfur white, highly dispersible sulfur, insoluble sulfur, precipitated sulfur, surface-treated sulfur, colloidal sulfur, sulfur chloride, sulfur monochloride, sulfur dichloride and the like. These sulfur vulcanizing agents can be used alone or in admixture of two or more. Further, when a sulfur vulcanizing agent is used as the vulcanizing / crosslinking agent, a vulcanization accelerator can be used in combination.

  Examples of the vulcanization accelerator include hexamethylenetetramine, aldehyde ammonia such as acetaldehyde / ammonia; n-butyraldehyde-aniline condensation product, butyraldehyde-monobutylamine condensation product, heptaldehyde-aniline reaction product, tricrotonylidene, Aldehyde amines such as tetramine; guanidine salts such as diphenylguanidine, geotril guanidine, ortho-tolyl-biguanide, dicatechol-boric acid diort-tolyl-guanidine salt; imidazolines such as 2-mercaptoimidazoline; 2-mercapto Benzothiazole, 2-mercaptothiazoline, dibenzothiazyl disulfide, zinc salt of 2-mercaptobenzothiazole, sodium salt of 2-mercaptobenzothiazole, 2-mercaptobenzo Cyclohexylamine salt of azole, 2- (2,4-dinitrophenylthio) benzothiazole, 2- (N, N-diethylthio-carbamoylthio) benzothiazole, 2- (4′-morpholino-dithio) benzothiazole, 4- Thiazoles such as morpholin-2-benzothiazyl disulfide;

  N-cyclohexyl-2-benzothiazyl sulfenamide, N, N-dicyclohexyl-2-benzothiazyl sulfenamide, N-oxydiethylene-2-benzothiazyl sulfenamide, N, N-diisopropyl-2-benzothiazyl sulfenamide Sufenamides such as phenamide, N-tert-butyl-2-benzothiazyl sulfenamide; thiocarbanide, ethylene thiourea (2-mercaptoimidazoline), diethyl thiourea, dibutyl thiourea, mixed alkylthiourea, trimethylthio Thioureas such as urea and dilauryl thiourea; sodium dimethyl dithiocarbamate, sodium diethyl dithiocarbamate, sodium di-n-butyl carbamate, lead dimethyl dithiocarbamate, diamyl Lead dithiocarbamate, zinc dimethyldithiocarbamate, zinc diamyl / dithiocarbamate, zinc diethyl / dithiocarbamate, zinc di-n-butyl / dithiocarbamate, zinc dibenzyl / dithiocarbamate, zinc N-pentamethylene / dithiocarbamate, ethylphenyl / dithiocarbamate Zinc, selenium dimethyl dithiocarbamate, selenium diethyl dithiocarbamate, tellurium diethyl dithiocarbamate, cadmium diethyl dithiocarbamate, copper dimethyl dithiocarbamate, iron dimethyl dithiocarbamate, bismuth dimethyl dithiocarbamate, piperidine dimethyl dithiocarbamate, Dithiocarbamate such as methylpentamethylene dipicarbamate pipecoline, activated dithiocarbamate Tetramethylthiuram monosulfide, tetramethylthiuram disulfide, active tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide, N, N'-dimethyl-N, N'-diphenylthiuram Thiurams such as disulfide, dipentamethylene thiuram disulfide, dipentamethylene thiuram tetrasulfide, mixed alkyl thiuram disulfide; xanthates such as sodium isopropyl xanthate, zinc isopropyl xanthate, zinc butyl xanthate; 4,4′-dithiodimorpholine, aminodialkyldithiophosphate, zinc-o, on-butyl phosphorodithioate, 3-mercaptoimidazoline-thione-2 And thioglycolic acid esters. These vulcanization accelerators can be used alone or in admixture of two or more.

  Examples of the organic peroxide include 1,1-ditert-butylperoxy-3,3,5-trimethylcyclohexane, ditert-butyl peroxide, tert-butylcumyl peroxide, dicumyl peroxide, 2,5 -Dimethyl-2,5-di (tert-butylperoxy) hexane), 2,5-dimethyl-2,5-di (tert-butylperoxy) hexyne, 1,3-bis (tert-butylperoxy-) Isopropyl) benzene, tert-butylperoxy-isopropyl carbonate, acetylcyclohexylsulfonyl peroxide, isobutyl peroxide, diisopropyl peroxydicarbonate, diallyl peroxydicarbonate, dipropylperoxydicarbonate, di (2-ethoxyethyl) per Oxydicarbonate, di (methoxyi Propyl) peroxydicarbonate, di (2-ethylhexyl) peroxydicarbonate, tert-hexylperoxyneohexanate, di (3-methyl-3-methyloxybutyl) peroxydicarbonate, tert-butylperoxyneodecanate , Tert-hexylperoxyneodecanate, tert-butylperoxyneohexanoate, 2,4-dichlorobenzoyl peroxide, tert-hexylperoxypivalate, tert-butylperoxypivalate, 3,3,5-trimethyl Hexanoyl peroxide, octanoyl peroxide, decanoyl peroxide, lauroyl peroxide, cumyl peroxy octate, acetyl peroxide, tert-butyl peroxy (2-ethyl hexanate), benzoyl peroxide, Butyl peroxyisoisobutyrate, 1,1-bis (tertiary butyl peroxy) cyclohexane, tert-butyl peroxymaleic acid, tert-butyl peroxylaurate, tert-butyl peroxy-3,3,5- Trimethylhexanate, cyclohexanone peroxide, tert-butylperoxyallyl carbonate, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, 2,2-bis (tert-butylperoxy) octane, third Butyl peroxyacetate, 2,2-bis (tert-butylperoxy) butane, tert-butylperoxybenzoate, butyl-4,4-bis (tert-butylperoxy) valerate, di-tert-butyldiperoxyiso Phthalate, methyl ethyl ketone peroxide, α, α'-bis Oxy-m-isopropyl) cyclohexane, diisopropylbenzene-hydroperoxide, p-menthane hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide, Examples include cumene hydroperoxide and tert-butyl hydroperoxide. These organic peroxides can be used alone or in admixture of two or more.

  Further, when an organic peroxide is used as the vulcanizing / crosslinking agent, a co-crosslinking agent can be used in combination. Examples of co-crosslinking agents include sulfur, p-quinone dioxime, p-benzoquinone dioxime, p, p'-dibenzoylquinone dioxime, N-methyl-N'-4-dinitrosoaniline, N, N-m-phenylene. Bismaleimide, dipentamethylene thiuram pentasulfide, dinitrosobenzene, divinylbenzene, triallyl cyanurate, triallyl isocyanurate, triazine thiol, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di ( (Meth) acrylate, polyethylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, trimetrolepropane tri (meth) acrylate , Erythritol tetra (meth) acrylate, diallyl melamine, divinyl adipate, vinyl butyrate, vinyl stearate, liquid polybutadiene rubber, liquid polyisoprene rubber, liquid styrene-butadiene rubber, liquid acrylonitrile-butadiene rubber, magnesium (meth) acrylate, Examples include calcium (meth) acrylate, aluminum (meth) acrylate, zinc (meth) acrylate, stannous (meth) acrylate, and magnesium (meth) acrylate. These co-crosslinking agents can be used alone or in admixture of two or more.

  Examples of the quinoid vulcanizing agent include p-quinone dioxime, p, p'-dibenzoylquinone dioxime, tetrachloro-p-benzoquinone, poly-p-dinitrobenzene and the like. These quinoid vulcanizing agents can be used alone or in admixture of two or more. Examples of the resin vulcanizing agent include alkylphenol-formaldehyde resin, melamine-formaldehyde condensate, triazine-formaldehyde condensate, octylphenol-formaldehyde resin, alkylphenol-sulfide resin, hexamethoxymethyl-melamine resin, and the like. These resin vulcanizing agents can be used alone or in admixture of two or more. Examples of the metal oxide vulcanizing agent include zinc oxide, magnesium oxide, lead monoxide and the like. These metal oxide vulcanizing agents can be used alone or in admixture of two or more.

  Examples of the sulfur-containing organic vulcanizing agent include morpholine disulfide, alkylphenol disulfide, N, N′-dithio-bis (hexahydro-2H-azepinone-2), thiuram polysulfide, 2- (4′-morpholino dithio) benzothiazole, and the like. Can be mentioned. These sulfur-containing organic vulcanizing agents can be used alone or in admixture of two or more.

  Examples of the polyamine vulcanizing agent include hexamethylenediamine carbamate, hexamethylenediamine, triethylene / tetramine, tetraethylene / pentamine, 4,4′-methylenebis (cyclohexylamine) carbamate, N, N′—. Examples include dicinnamylidene-1,6-hexanediamine and ammonium benzoate. These polyamine vulcanizing agents can be used alone or in admixture of two or more. Examples of the triazine vulcanizing agent include 2,4,6-trimercapto-s-triazine, 2-di-n-butylamino-4,6-dimercapto-s-triazine and the like. These triazine vulcanizing agents can be used alone or in admixture of two or more.

  Examples of the polyol vulcanizing agent include bisphenol A, bisphenol AF, hydroquinone, pentaerythritol and the like. These polyol vulcanizing agents can be used alone or in admixture of two or more. Examples of the metal soap vulcanizing agent include sodium stearate, potassium stearate, sodium oleate, potassium oleate and the like. These metal soap vulcanizing agents can be used alone or in admixture of two or more. Examples of the maleimide vulcanizing agent include N, N′-m-phenylene dimaleimide.

  The crosslinking agent for hydrosilylation reaction is an organopolysiloxane having an average of two or more silicon-bonded hydrogen atoms in one molecule. The molecular structure of the organopolysiloxane is not particularly limited, and may be, for example, a linear, branched, cyclic, or three-dimensional network resinous material. Examples of the organic group bonded to the silicon atom include an alkyl group such as methyl group, ethyl group, propyl group, butyl group, pentyl group, and hexyl group; aryl group such as phenyl group, tolyl group, and xylyl group; benzyl group, Aralkyl groups such as phenethyl group; halogenated alkyl groups such as 3-chloropropyl group and 3,3,3-trifluoropropyl group are exemplified, and methyl group is preferable.

    Examples of such an organopolysiloxane include dimethylpolysiloxane blocked with dimethylhydrogensiloxy group at both ends of the molecular chain, dimethylsiloxane / methylphenylsiloxane copolymer blocked with dimethylhydrogensiloxy group at both ends of the molecular chain, and trimethylsiloxy group at both ends of the molecular chain. Blocked dimethyl siloxane / methyl hydrogen siloxane copolymer, molecular chain both ends dimethyl siloxane / methyl phenyl siloxane / methyl hydrogen siloxane copolymer, molecular chain both ends dimethyl hydrogen siloxy group blocked dimethyl siloxane / methyl hydrogen siloxane copolymer Examples thereof include a combination and a mixture of two or more of these organopolysiloxanes.

  Examples of the hydrosilylation reaction catalyst for promoting the hydrosilylation reaction include platinum-based catalysts, rhodium-based catalysts, iridium-based catalysts, palladium-based catalysts, and ruthenium-based catalysts, with platinum-based catalysts being preferred. Specifically, platinum fine powder, platinum black, chloroplatinic acid, platinum tetrachloride, alcohol-modified chloroplatinic acid, platinum olefin complexes, platinum alkenylsiloxane complexes, platinum carbonyl complexes, and methyl containing these platinum-based catalysts Platinum-based catalysts such as thermoplastic organic resin powders such as methacrylate resin, polycarbonate resin, polystyrene resin, and silicone resin.

  Furthermore, the heat-shrinkable rubber composition of the present invention can be blended with various additives used in ordinary rubber compositions. Such additives include anti-aging agents, antioxidants, processing aids, activators, UV absorbers, tackifiers, lubricants, water repellents, waxes, activators, light stabilizers, coupling agents, Internal mold release agent, scorch inhibitor, foaming agent, foaming aid, antibacterial agent, flame retardant, peptizer, heat storage agent, electronic conductivity imparting agent, ionic conductivity imparting agent, thermal conductivity imparting agent, heat dissipation agent, phosphorescent agent In addition, a colorant, a thermoplastic resin, a thermoplastic crosslinked elastomer, and the like can be blended.

<Preparation of heat shrink composition>
In the present invention, the rubber component (A), the side chain crystalline polymer (B), the softening agent (C), the filler (D) and the crosslinking agent (E) are added with other compounding agents as required, A heat-shrinkable rubber composition that can be vulcanized can be prepared by thoroughly mixing and kneading. As the mixing method, the following method will be described as an example.

  The rubber composition of the present invention can be usually prepared by an ordinary rubber kneader such as an extruder, a twin screw extruder, a Banbury mixer, a kneader, or a mixing roll. The rubber composition of the present invention is excellent in molding processability, and is easily molded by press molding, extrusion molding, injection molding, transfer molding, calendar molding and the like used in normal rubber processing. In the case where crosslinking is involved, crosslinking is performed by press crosslinking, UHF crosslinking, electron beam crosslinking, HAV crosslinking, ultraviolet crosslinking, or the like.

EXAMPLES Next, although an Example demonstrates this invention, this invention is not limited at all by these Examples.
Here, the shape recovery rate and the shape memory rate can be measured according to the method described below.
First, the heat-shrinkable rubber composition of the present invention was vulcanized in a mold at 170 ° C. for 10 minutes using a press molding machine with a thickness of 2.2 to 2.5 mm. A vulcanized sheet of 2 mm (thickness) × 15 cm (length) × 15 cm (width) is obtained. A test piece is prepared by punching the vulcanized sheet into a rectangular plate of 10 mm (width) × 60 mm (length).

Next, a 30 mm mark is drawn in the length direction of the center of the test piece, and the test piece is deformed using a jig so that the mark becomes 60 mm, and placed in an oven at 80 ° C. for 10 minutes. Thereafter, the test piece is taken out of the oven and cooled with water. One day after removing the jig, the distance between the marked lines (L ₁ ) drawn on the surface of the test piece is measured. Next, the test piece is put again in an oven at 80 ° C., left for 10 minutes, then taken out, left at room temperature for 30 minutes, and then the distance between marked lines (L ₂ ) is measured again.

The shape recovery rate and the shape memory rate are calculated according to the following equations using the distances between marked lines (L ₁ ) and (L ₂ ) measured as described above.
Shape recovery rate [%] = [(L ₁ −L ₂ ) × 100] / [L ₁ −30]
Shape memory ratio [%] = [(L ₁ -30) × 100] / [60-30]

Production of side chain crystalline polymer (B) (Production Example 1)
After adding 140 g of “Linearene 2024” (mainly a mixture of α-olefins having 20, 22 and 24 carbon atoms) and 200 ml of heptane to a 1 liter autoclave which has been dried by heating, the temperature is adjusted to 50 ° C. 1 mmol of triisobutylaluminum, 5 μmol of (1,2′-dimethylsilylene) (2,1′-dimethylsilylene) bis (3-trimethylsilylmethylindenyl) zirconium dichloride, dimethylanilinium tetrakispentafluorophenylborate 25 Micromol was added, 0.03 MPa of hydrogen was introduced, and copolymerization was performed for 1 hour.
After completion of the copolymerization reaction, the reaction product was precipitated with acetone, and then dried under heating and reduced pressure to obtain 1:80 g of a crystalline higher α-olefin polymer.
About the obtained copolymer, melting | fusing point (Tm) and the weight average molecular weight (Mw) were measured with the following measuring method.

[DSC measurement]
Using a differential scanning calorimeter (Perkin Elmer, DSC-7), 10 mg of component (B) was held at 190 ° C. for 5 minutes in a nitrogen atmosphere, and then decreased to −10 ° C. at 5 ° C./min, −10 After maintaining at 5 ° C. for 5 minutes, the melting point (Tm) of the peak top of the melting peak observed from the melting endothermic curve obtained by raising the temperature to 190 ° C. at 10 ° C./min was measured.
(Weight average molecular weight)
As the weight average molecular weight (Mw), a polystyrene conversion value obtained from a standard polystyrene calibration curve was used.
GPC measuring device column: TOSO GMHHR-H (S) HT
Detector: RI detector for liquid chromatogram WATERS 150C
Measurement conditions Solvent: 1,2,4-trichlorobenzene Measurement temperature: 145 ° C
Flow rate: 1.0 ml / min Sample concentration: 2.2 mg / ml Injection volume: 160 microliter Calibration curve: Universal Calibration
Analysis program: HT-GPC (Ver.1.0)
As a result, the melting point (Tm) was 48.6 ° C.
Note that there was one peak observed when the melting point (Tm) was measured.
The weight average molecular weight (Mw) was 4.8 × 10 ⁴ .

(Production Example 2)
To a heat-dried 1 liter autoclave, 200 ml of heptane, 200 ml of 1-octadecene (C ₁₈ ), 0.5 mmol of triisobutylaluminum, 1 mmol of methylaluminoxane were added, and 0.03 MPa of hydrogen was further introduced.
The temperature was raised to 60 ° C. with stirring, and then (1,2′-dimethylsilylene) (2,1′-dimethylsilylene) (3-trimethylsilylmethylindenyl) (indenyl) zirconium dichloride obtained in Production Example 3 was used. 1 micromole was added and polymerized for 30 minutes.
After completion of the polymerization reaction, the reaction product was heated and dried under reduced pressure to obtain 2:25 g of a higher α-olefin polymer.
As a result, the melting point (Tm) was 41.1 ° C.
Note that there was one peak observed when the melting point (Tm) was measured.
The weight average molecular weight (Mw) was 1.5 × 10 ⁵ .

(Production Example 3)
After adding 2500 g of “Linearene 2024” (mainly a mixture of α-olefins having 20, 22 and 24 carbon atoms) and 2500 ml of heptane to Idemitsu Kosan Co., Ltd. and heating to 10 liter autoclave, the temperature was raised to 80 ° C. 6 mmol of triisobutylaluminum, 20 μmol of (1,2′-dimethylsilylene) (2,1′-dimethylsilylene) bis (3-trimethylsilylmethylindenyl) zirconium dichloride, dimethylanilinium tetrakispentafluorophenylborate 100 Micromol was added, 0.8 MPa of hydrogen was introduced, and copolymerization was performed for 5 hours.
After completion of the copolymerization reaction, the reaction product was precipitated with acetone, and then dried under heating and reduced pressure to obtain 3: 100 g of a crystalline higher α-olefin copolymer.
As a result, the melting point (Tm) was 52.9 ° C.
Note that there was one peak observed when the melting point (Tm) was measured.
The weight average molecular weight (Mw) was 1.9 × 10 ⁵ .

Example 1
The rubber component (A), side chain crystalline polymer (B), softener (C), filler (D) and vulcanizing agent (E) used are as follows. Other additives are shown in Table 1.
(1) Rubber component (A) EPDM and EP51 manufactured by JSR Corporation
(2) Side chain crystalline polymer (B): higher α-olefin copolymer 1 of Production Example 1
(3) Softener (C): Aromatic process oil manufactured by Idemitsu Kosan Co., Diana Process AC-
460
(4) Filler (D): Carbon black manufactured by Tokai Carbon Co., Seast SO
(5) Vulcanizing agent (E): Organic peroxide vulcanizing agent manufactured by Nippon Oil & Fats, Parkmill D-40

First, various compounding agents were kneaded at a temperature of 80 ° C. or more for 5 minutes using a Banbury mixer at a ratio shown in Table 1 to obtain a compound.

  Next, a 6-inch thiol roll whose roll surface temperature was set to 60 ° C. for the front roll and 60 ° C. for the rear roll was prepared, and the above blend was wound around the roll. Next, various vulcanizing agents were added, kneaded and dispensed to obtain an unvulcanized sheet having a thickness of 2.2 mm.

  This unvulcanized sheet is press-molded in a mold at 170 ° C. for 10 minutes using a press molding machine to obtain a 2 mm (thickness) × 15 cm (vertical) × 15 cm (horizontal) vulcanized sheet. Obtained. Next, a 10 mm (width) × 60 mm (length) rectangular test piece was punched from this vulcanized sheet, and using this test piece, the shape memory rate and the shape recovery rate were determined by the method described above. It was described in.

(Example 2) In Example 1, as the rubber component (A), EPSR and EP57C manufactured by JSR, the higher α-olefin polymer 2 of Production Example 2 as a side chain crystalline polymer (B), a vulcanizing agent ( The same procedure as in Example 1 was conducted except that sulfur was used as E). The results are shown in Table 1.

(Example 3) In Example 1, as the side chain crystalline polymer (B), the higher α-olefin polymer 3 of Production Example 3, and as the softener (C), naphthenic process oil manufactured by Idemitsu Kosan Co., Ltd., NS-100 The same procedure as in Example 1 was performed except that activated calcium carbonate and white gloss flower CC manufactured by Shiroishi Kogyo Co., Ltd. were newly used as the filler (D). The results are shown in Table 1.

(Example 4) The same operation as in Example 2 was conducted except that the amount of the side chain crystalline polymer (B) added was 50 parts by weight. The results are shown in Table 1.

(Comparative Example 1) The same procedure as in Example 1 was performed except that the side chain crystalline polymer (B) was omitted. The results are shown in Table 1.

(Comparative example 2) In Example 2, it carried out similarly to Example 2 except having used polystyrene and G747R by a Japan polystyrene company instead of the side chain crystalline polymer (B). The results are shown in Table 1.

From Table 1, it can be seen that in Examples 1 to 4, the shape memory rate and the shape recovery rate necessary for the heat-shrinkable rubber are extremely excellent. Compared to this, it can be seen that comparative example 1 shows almost no shape memory rate, and comparative example 2 is inferior to the examples both in shape memory rate and shape recovery rate.

Claims (12)

  3 parts by weight to 100 parts by weight of the side chain crystalline polymer (B), 100 parts by weight of the rubber component (A), softener (C), filler (D) and vulcanizing agent (E) are included. Heat shrinkable rubber composition.   The heat-shrinkable rubber composition according to claim 1, wherein the rubber component (A) is an ethylene / α-olefin / non-conjugated polyene copolymer rubber.   The ethylene / α-olefin / non-conjugated polyene copolymer rubber is an ethylene / propylene / dicyclopentadiene copolymer rubber, ethylene / propylene / 5-ethylidene-2-norbornene copolymer rubber, ethylene / propylene / 1, 4. Hexadiene copolymer rubber, ethylene / 1-butene / 1,4-hexadiene copolymer rubber, ethylene / propylene / 5-vinyl-2-norbornene copolymer rubber The heat shrinkable rubber composition according to claim 1.   The heat-shrinkable rubber composition according to any one of claims 1 to 3, wherein the side chain crystalline polymer (B) has a melting point of 100 ° C or lower.   The heat-shrinkable rubber composition according to any one of claims 1 to 4, wherein the side chain crystalline polymer (B) has a melting point in the range of 30 ° C to 80 ° C.   The heat-shrinkable rubber composition according to any one of claims 1 to 5, wherein the side chain crystalline polymer (B) mainly comprises an α-olefin unit having 10 or more carbon atoms.   The side chain crystalline polymer (B) is an α-olefin homopolymer and / or copolymer mainly comprising an α-olefin unit having 10 or more carbon atoms. The heat-shrinkable rubber composition as described.   A vulcanized molded product obtained by vulcanization molding from the heat-shrinkable rubber composition according to any one of claims 1 to 7.   The vulcanized molded product according to claim 8, which is used for a heat-shrinkable tube.   Busbar insulation (generator, vehicle rotating machine), motor, transformer, switching regulator insulation (TV, VTR) insulation of various sensors (electronic jar, hot air heater, stove) terminal insulation of various heaters (seeds, The heat-shrinkable tube used for terminal insulation (dryer, precision equipment, robot, automobile, physics and chemistry equipment) of various harnesses (cartridge, throwing heater)   The said heat shrinkable tube used for the joint of the joint part of a metal pipe and / or a nonmetal pipe.   Wire / cable wiring connections and terminal protection, for mechanical applications, automotive hoses, pipe covers and roller covers, sewer pipe joint waterproof covers, steel pipe anticorrosion, grips, anti-slip railing, electric lights, fluorescent lights, various types The heat-shrinkable tube used for a cover for preventing damage to a container and an adhesive label that does not use an adhesive for a container for recycling.