JP2013245256A - Elastomer composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an elastomer composition having high vapor barrier performance, and excellent mechanical strength.SOLUTION: An elastomer composition contains: (A) a curable resin of 100 pts.mass containing at least a hydrogenated conjugated diene (co)polymer including a (meth)acryloyl group; and (B) a polystyrene-based thermoplastic elastomer of 10 to 100 pts.mass. Another elastomer composition is obtained by irradiating the above elastomer composition with active energy ray. The above elastomer is used for encapsulation material.

Description

  The present invention relates to an elastomer composition. Specifically, an elastomer composition containing a hydrogenated conjugated diene (co) polymer having a (meth) acryloyl group and a polystyrene-based thermoplastic elastomer, an elastomer composition obtained by irradiating the elastomer composition with active energy rays, And it is related with the said elastomer composition which is an object for sealing materials.

In recent years, various photocurable resins have been developed for applications requiring water vapor barrier properties such as sealing materials, adhesives, and sealing materials.
For example, Patent Document 1 discloses a polyether polyol-based photocurable resin for surface processing of woodwork products such as woodworking plywood, furniture, and musical instruments. However, since polyether polyol has high hydrophilicity and high water vapor permeability, it is unsuitable for use in sealing materials and gasket materials that require water vapor barrier properties.
A polybutadiene-based photocurable resin composition is known as one that improves the water vapor permeability. For example, Patent Document 2 discloses that a hydroxyl group of a polymer having a polymer chain obtained by polymerizing butadiene with a 1,2-bond or a hydrogenated polymer chain and having a hydroxyl group in the molecule is acryloyl. An adhesive for optical instruments and precision machines using liquid polybutadiene (meth) acrylate modified with a polymerizable functional group such as a group or a methacryloyl group is disclosed. However, these have a low molecular weight as a 1,2-bond or hydrogenated polybutadiene-based photocurable resin, so that the molecular weight between cross-linking points is small and high cross-linking results in hindering rubber elasticity. Since it has a high modulus of elasticity, no elongation, low tensile strength, and poor fatigue, it was not practical due to cracking when used in gaskets, packing, sealing materials, and the like.
Also, a hydrogenated conjugated diene-based (co) polymer polymerized with a specific initiator as a suitable material for a sealing material having high water vapor barrier properties, excellent heat resistance, and suitable hardness as a rubber elastic material A method for producing a photocurable liquid resin has been reported by introducing a photocurable unsaturated hydrocarbon group at the end of the polymer (Patent Document 3). Although it is possible to improve the mechanical strength and water vapor barrier property by blending and formulating a plurality of photocurable materials containing the material, further improvements in these two points were insufficient with only the photocurable material. .

Japanese Patent Laid-Open No. 5-202163 JP 2002-371101 A JP 2007-145949 A

  An object of the present invention is to provide an elastomer composition having higher water vapor barrier properties and excellent mechanical strength under such circumstances.

  As a result of intensive investigations by paying attention to the above problems, the present inventors have found that (A) a curable resin containing at least a hydrogenated conjugated diene (co) polymer having a (meth) acryloyl group and (B) a polystyrene-based thermoplastic elastomer. Is found to be effective in improving the water vapor barrier properties and mechanical strength, and by setting these proportions within a specific range, an elastomer composition having particularly high water vapor barrier properties and excellent mechanical strength can be obtained. As a result, the present invention was completed.

That is, the present invention relates to the following [1] to [7].
[1] (A) 100 parts by mass of a curable resin containing at least a hydrogenated conjugated diene (co) polymer having a (meth) acryloyl group, and (B) 10 to 100 parts by mass of a polystyrene-based thermoplastic elastomer. The elastomer composition characterized by the above-mentioned.
[2] The component (B) is a styrene-isobutylene-styrene block copolymer (SIBS), a styrene-butadiene-styrene block copolymer (SBS), or a styrene-ethylene / butylene-styrene block copolymer (SEBS). And the elastomer composition according to [1], which is at least one selected from styrene-ethylene / propylene-block copolymer (SEPS).
[3] The elastomer composition according to [1] or [2], wherein the component (B) has a weight average molecular weight of 50,000 or more.
[4] The hydrogenated conjugated diene (co) polymer having a (meth) acryloyl group is a hydrogenated styrene-butadiene copolymer or a hydrogenated butadiene homopolymer having a (meth) acryloyl group. [1] -Elastomer composition in any one of [3].
[5] The elastomer composition according to any one of [1] to [4], further containing a (meth) acrylate monomer as the curable resin (A).
[6] An elastomer composition obtained by irradiating an active energy ray to the elastomer composition according to any one of [1] to [5].
[7] The elastomer composition according to any one of [1] to [5], which is for a sealing material.

  According to the present invention, an elastomer composition having a high water vapor barrier property and excellent mechanical strength that exhibits high breaking strength and elongation at break can be obtained.

[Elastomer composition]
The elastomer composition of the present invention comprises (A) 100 parts by mass of a curable resin containing at least a hydrogenated conjugated diene (co) polymer having a (meth) acryloyl group, and (B) a polystyrene-based thermoplastic elastomer 10 to 100. Contains parts by weight.
Hereinafter, each component contained in the elastomer composition of the present invention will be described in detail.

<(A) curable resin>
The curable resin (A) used in the present invention is composed of a compound having a polymerizable unsaturated bond such as an acryloyl group, and at least a hydrogenated conjugated diene (co) polymer (A-) having a (meth) acryloyl group. 1) and optionally (meth) acrylate monomer (A-2).

<< (A-1) Hydrogenated conjugated diene (co) polymer having a (meth) acryloyl group >>
The hydrogenated conjugated diene (co) polymer (A-1) used in the present invention has a (meth) acryloyl group. Further, the (meth) acryloyl group is preferably present at the terminal of the hydrogenated conjugated diene (co) polymer or at a site where a hydroxyl group is introduced at the terminal. The (meth) acryloyl group means an acryloyl group and / or a methacryloyl group. The (co) polymer means a copolymer of two or more monomers and / or a homopolymer of one monomer.

Examples of the hydrogenated conjugated diene (co) polymer in the component (A-1) include hydrogenated products of copolymers of vinyl aromatic compounds and conjugated dienes, and hydrogenated products of conjugated diene homopolymers. Can be mentioned.
Examples of the vinyl aromatic compound used in the hydrogenated conjugated diene (co) polymer include styrene, α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, and pt-butyl. Styrene, divinylbenzene, diisopropenyl styrene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, 1,1-diphenylethylene, N, N′-dimethyl-p-aminostyrene, N, N′-diethyl -P-aminostyrene, vinylpyridine and the like can be mentioned, and among these, styrene and α-methylstyrene are preferable.
Examples of the conjugated diene used in the hydrogenated conjugated diene (co) polymer include butadiene, isoprene, 2,3-dimethylbutadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 1, Examples include 3-hexadiene, 4,5-diethyl-1,3-octadiene, 3-butyl-1,3-octadiene, chloroprene, and 2,3-dichlorobutadiene. Among these, butadiene is preferable.

  Among the above hydrogenated conjugated diene (co) polymers, a hydrogenated styrene-butadiene copolymer or a hydrogenated butadiene homopolymer is preferable. By using these, a photocurable resin material having a more remarkable water vapor barrier property can be obtained. When using a hydrogenated styrene-butadiene copolymer, the content of the structural unit derived from styrene of the copolymer (hereinafter referred to as styrene content) is not particularly limited, Preferably it is 10-40 mass%, More preferably, it is 10-30 mass%.

The weight average molecular weight of the component (A-1) is preferably 5,000 to 40,000, more preferably 6,000 to 30,000, and still more preferably 7,000 to 20,000. In addition, in this specification, a weight average molecular weight is the value calculated | required by polystyrene conversion on the basis of the monodispersed polystyrene by the gel permeation chromatography (GPC).
The molecular weight distribution (Mw / Mn) is preferably 3 or less, more preferably 2 or less, and still more preferably 1.2 or less. When the weight average molecular weight of the component (A-1) is within this range, the viscosity of the component (A-1) does not become too high and the handleability is good. Further, when the molecular weight distribution is 3 or less, reproducibility is easily obtained in mass production, and it becomes easy to obtain a polymer having the same molecular weight.

  Although there is no restriction | limiting in particular as a manufacturing method of the hydrogenated conjugated diene (co) polymer (A-1) which has the said (meth) acryloyl group, For example, the hydrogenated conjugated diene (co) by which the hydroxyl group was introduce | transduced into the molecular terminal. A method of reacting a polymer with a compound having a (meth) acryloyl group is preferred.

  The starting conjugated diene (co) polymer can be obtained by homopolymerization of a conjugated diene or copolymerization of a vinyl aromatic compound and a conjugated diene. For example, known dilithium compounds such as naphthalenedilithium and dilithiohexylbenzene And a method of copolymerizing styrene and 1,3-butadiene at 10 to 80 ° C. in the presence of a solvent inert to the reaction.

  The method for introducing a hydroxyl group into the molecular terminal of the hydrogenated conjugated diene (co) polymer is not particularly limited, but by reacting the conjugated diene (co) polymer with an epoxy compound such as ethylene oxide or propylene oxide, Examples thereof include a method of introducing a hydroxyl group at the molecular end.

The hydrogenated conjugated diene (co) polymer can be obtained by hydrogenating a conjugated diene (co) polymer or a conjugated diene (co) polymer having a hydroxyl group introduced at the molecular end. There is no particular limitation on the method of hydrogenating the conjugated diene (co) polymer or the conjugated diene (co) polymer having a hydroxyl group introduced at the molecular end, and a known method can be used. For example, by reacting a conjugated diene (co) polymer in a saturated hydrocarbon solution such as cyclohexane in the presence of a known hydrogenation catalyst and under hydrogen pressure at 50 to 180 ° C., a part of the conjugated diene moiety. Alternatively, all can be hydrogenated. As a hydrogenation catalyst, Raney nickel or a heterogeneous catalyst in which a metal such as Pt, Pd, Ru, Rh, Ni or the like is supported on a carrier such as carbon, alumina, diatomaceous earth: Group 8-10 metals such as nickel and cobalt Ziegler-type catalyst comprising a combination of an organometallic compound consisting of an organoaluminum compound such as triethylaluminum and triisobutylaluminum or an organolithium compound: a bis (cyclopentadienyl) compound of a transition metal such as titanium, zirconium or hafnium; Examples thereof include metallocene catalysts composed of a combination of organometallic compounds such as lithium, sodium, potassium, aluminum, zinc or magnesium.
The hydrogenation rate of the conjugated diene (co) polymer or the conjugated diene (co) polymer having a hydroxyl group introduced at the molecular end is not particularly limited, but is preferably 80 to 100%, more preferably from the viewpoint of heat resistance. 90 to 100%.

  Examples of the reaction with the compound having the (meth) acryloyl group include a urethanation reaction using a hydrogenated conjugated diene (co) polymer having a hydroxyl group introduced at the molecular end and 2- (meth) acryloyloxyethyl isocyanate, or the like; Transesterification reaction between a hydrogenated conjugated diene (co) polymer having a hydroxyl group introduced at the molecular end and a lower alkyl (meth) acrylate such as methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate; Hydrogenated conjugated diene having a photocurable functional group by reaction of a prepolymer obtained by reacting a hydrogenated conjugated diene (co) polymer having a hydroxyl group introduced with it with an isocyanate compound and 2-hydroxyethyl acrylate, etc. A (co) polymer can be obtained.

<< (A-2) (meth) acrylate monomer >>
The curable resin (A) preferably contains a (meth) acrylate monomer (A-2).
The (meth) acrylate monomer is not particularly limited, and examples thereof include (meth) acrylic acid and alkyl (meth) acrylate.

Among these (meth) acrylate monomers (A-2), alkyl (meth) acrylate is preferable from the viewpoint of improving water vapor barrier properties. The ester residue of the alkyl (meth) acrylate is preferably an alkyl group having 8 to 18 carbon atoms. The ester residue is not particularly limited, but is a cyclic saturated hydrocarbon group such as isobornyl group, cyclohexyl group, dicyclopentanyl group, dicyclopentenyl group, dicyclopentanyloxyethyl group, dicyclopentenyloxyethyl group, etc. Or nonylphenoxy polyalkylene glycol residue. Here, the polyalkylene glycol is polyethylene glycol and / or polypropylene glycol.
In the present specification, the ester residue of the (meth) acrylate monomer means a residue obtained by removing one hydroxyl group of the hydroxyl group-containing compound from the (meth) acrylic acid and the hydroxyl group-containing compound constituting the (meth) acrylate monomer. Means group. Furthermore, (meth) acrylate means acrylate and / or methacrylate, and (meth) acrylic acid means acrylic acid and / or methacrylic acid.

  Specifically, (meth) acrylate monomer (A-2) is isobornyl (meth) acrylate, cyclohexyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, isostearyl (meth) ) Acrylate, isomyristyl (meth) acrylate, lauryl (meth) acrylate, dicyclopentanyloxyethyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, nonylphenoxy polyethylene glycol (meth) acrylate, nonylphenoxy polypropylene glycol (Meth) acrylate, nonylphenoxypolyethylene glycol-polypropylene glycol (meth) acrylate, nonylphenoxypolypropylene glycol-polyethylene Glycol (meth) acrylate. Among these, isobornyl (meth) acrylate is preferable from the viewpoint of remarkable improvement in water vapor barrier properties.

  The content of the component (A-2) is preferably 5 to 70% by mass, more preferably 10 to 60% by mass, and further preferably 20 to 50% by mass in the curable resin (A). . By containing in such a range, it becomes easy to obtain the elastomer composition which has moderate hardness.

<(B) polystyrene-based thermoplastic elastomer>
The (B) component polystyrene-based thermoplastic elastomer has an aromatic vinyl polymer block (hard segment) and a rubber block (soft segment), and the aromatic vinyl polymer portion forms a physical crosslink. On the other hand, the rubber block gives elasticity.
Examples of the aromatic vinyl-based compound forming the aromatic vinyl-based polymer block include styrene; α-alkyl-substituted styrene such as α-methylstyrene, α-ethylstyrene, α-methyl-p-methylstyrene; o- Methyl styrene, m-methyl styrene, p-methyl styrene, 2,4-dimethyl styrene, ethyl styrene, 2,4,6-trimethyl styrene, ot-butyl styrene, pt-butyl styrene, p-cyclohexyl styrene Nuclear alkyl-substituted styrene such as o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, p-bromostyrene, 2-methyl-4-chlorostyrene and the like halogenated styrene; 1-vinylnaphthalene and the like vinylnaphthalene Derivatives; indene derivatives; divinylbenzene and the like.
Among these, styrene, α-methylstyrene, and p-methylstyrene are preferable, and styrene is particularly preferable.
These aromatic vinyl compounds may be used individually by 1 type, and may be used in combination of 2 or more type.
The content of the vinyl aromatic compound unit in the aromatic vinyl polymer block (hard segment) is preferably 80 mol% or more, more preferably 90 mol% or more, still more preferably 95 mol% or more, particularly preferably substantially. Is 100 mol%.

  Examples of the rubber block (soft segment) include a block of a conjugated diene compound, and examples of the conjugated diene compound include 1,3-butadiene and isoprene. These conjugated diene (co) polymer blocks may be hydrogenated products of blocks of conjugated diene compounds. The content of the conjugated diene compound unit in the rubber block (soft segment) is preferably 80 mol% or more, more preferably 90 mol% or more, still more preferably 95 mol% or more, and particularly preferably substantially 100 mol%. . Examples of other structural units include the vinyl aromatic compound units.

This polystyrene-based thermoplastic elastomer has a styrene-butadiene-styrene block copolymer (SBS), a styrene-isoprene-styrene block copolymer (SIS), and a styrene-isobutylene-styrene block depending on the arrangement pattern of the soft segments therein. Copolymer (SIBS), Styrene-ethylene / butylene-styrene block copolymer (SEBS; polystyrene-hydrogenated polybutadiene-polystyrene block copolymer), Styrene-ethylene / propylene-block copolymer (SEPS; polystyrene-water) Added polyisoprene-polystyrene block copolymer).
Among these, in terms of water vapor barrier properties and mechanical strength, styrene-isobutylene-styrene block copolymer (SIBS), styrene-butadiene-styrene block copolymer (SBS), styrene-ethylene / butylene-styrene block. A copolymer (SEBS) and a styrene-ethylene / propylene-block copolymer (SEPS) are preferred, and a styrene-isobutylene-styrene block copolymer (SIBS) is more preferred from the viewpoint of water vapor barrier properties. The content of the styrene block in these styrene elastomers is preferably 10 to 70% by mass, and more preferably in the range of 20 to 40% by mass.

The hardness of the elastomer component is preferably 80 degrees or less in accordance with JIS-A standards. When the hardness is 80 degrees or less, sufficient flexibility as a molded body can be obtained. In view of the above, the hardness is more preferably 70 degrees or less and particularly preferably 60 degrees or less in the JIS-A standard.
Further, the weight average molecular weight of the elastomer component is not particularly limited, but is preferably 50,000 or more and in the range of 50,000 to 120,000 in terms of water vapor barrier properties, mechanical strength, and the like. In particular, the range of 60,000 to 100,000 is preferable.
In addition, the elastomer component contained in a composition can be used individually by 1 type and in combination of 2 or more types.

  (B) Content of a component is 10-100 mass parts with respect to 100 mass parts of curable resin (A). If the content of the component (B) is at least 10 parts by mass or more, sufficient water vapor barrier properties cannot be obtained, and if it is not 100 parts by mass or less, it is difficult for molding. From such a viewpoint, the content of the component (B) is preferably 10 to 90 parts by mass, and more preferably 20 to 80 parts by mass.

<(C) Photopolymerization initiator>
The elastomer composition of the present invention preferably further contains a photopolymerization initiator as the component (C). As a photoinitiator, a well-known thing can be used widely and it does not restrict | limit in particular.
Examples thereof include intramolecular cleavage type photopolymerization initiators, and benzoin alkyl ether photopolymerization initiators such as benzoin ethyl ether, benzoin isobutyl ether, and benzoin isopropyl ether; 2,2-diethoxyacetophenone, 4′-phenoxy- Acetophenone photopolymerization initiators such as 2,2-dichloroacetophenone; 2-hydroxy-2-methylpropiophenone, 4′-isopropyl-2-hydroxy-2-methylpropiophenone, 4′-dodecyl-2-hydroxy Propiophenone photopolymerization initiators such as 2-methylpropiophenone; anthraquinone photopolymerization initiators such as benzyldimethyl ketal, 1-hydroxycyclohexyl phenyl ketone and 2-ethylanthraquinone, 2-chloroanthraquinone; Sid based photopolymerization initiators, and the like. Among these, acylphosphine oxide photopolymerization initiators are preferable.
Other hydrogen abstraction type photopolymerization initiators include benzophenone / amine photopolymerization initiators, Michler ketone / benzophenone photopolymerization initiators, and thioxanthone / amine photopolymerization initiators.
In order to avoid migration of the unreacted photopolymerization initiator, a non-extractable photopolymerization initiator can be used. For example, there are those obtained by polymerizing an acetophenone-based initiator and those obtained by adding a double bond of an acrylic group to benzophenone.
These photoinitiators may be used individually by 1 type, and may use 2 or more types together.
When the elastomer composition of this invention contains a photoinitiator, the content becomes with respect to 100 mass parts of (A) component, Preferably it is 0.1-20 mass parts, More preferably, it is 0.1-10. Part by mass, more preferably 0.5 to 5 parts by mass. Moreover, a well-known photosensitizer can also be used together with the said photoinitiator.

(Other optional ingredients)
In the elastomer composition of the present invention, softeners such as paraffinic oil, naphthenic oil, silicone oil, vegetable oil and the like as optional components as necessary, as long as the object of the present invention is not impaired; polypropylene Molding agents such as styrene; inorganic fillers such as talc, silica, calcium carbonate, magnesium carbonate, aluminum hydroxide, barium sulfate, glass fibers, glass powder, glass balloons, ceramic powder, mica; cork powder Organic filler such as wood powder, graphite, organic thixotropic agent, coupling agent, antioxidant (anti-aging agent), light stabilizer, flame retardant, antistatic agent, antibacterial agent, carbodiimides, stearic acid Fatty acid such as calcium stearate; stearic acid amide Fatty acid amides; fatty acid esters; ceramics, carbon black, amber, senna, kaolin, nickel titanium yellow, cobalt blue, plamaster gray, quinophthalone, diketopyrrolopyrrole, quinacridone, dioxazine, phthalocyanine blue, phthalocyanine green, etc .; leveling Agents; tackifiers such as rosin derivatives (tackifier); adhesive elastomers such as “Rheostomer® B” (trade name, manufactured by Riken Technos); coumarone resin, coumarone-indene resin, phenol terpene resin, etc. Can be contained. The elastomer composition of the present invention is basically solvent-free, but various solvents may be blended as necessary.
When the elastomer composition of the present invention contains the above optional component, the content thereof is preferably 20 parts by mass or less, more preferably 10 parts by mass or less, and still more preferably, with respect to 100 parts by mass of the component (A). 5 parts by mass or less.

[Method for Preparing Elastomer Composition]
The component (A) and the component (B), and if necessary, the component (C) and further the above optional components are mixed. For example, a uniaxial kneader, a biaxial kneader, a Banbury mixer, a brabender, a kneader, a high shear type The elastomer composition of the present invention can be obtained by kneading using a mixer or the like, preferably at 130 to 270 ° C, more preferably at 150 to 260 ° C, and even more preferably at 170 to 240 ° C.

In addition, the elastomer composition by which at least one part of the elastomer composition was hardened is obtained by irradiating an active energy ray to the elastomer composition obtained in this way. The elastomer composition after irradiation with active energy rays has high water vapor barrier properties, breaking strength and breaking elongation.
Examples of the active energy rays include particle rays, electromagnetic waves, and combinations thereof. Examples of the particle beam include an electron beam (EB) and an α ray, and examples of the electromagnetic wave include an ultraviolet ray (UV), a visible ray, an infrared ray, a γ ray and an X ray. Examples of the ultraviolet light source include a xenon lamp, a low-pressure mercury lamp, a high-pressure mercury lamp, a metal halide lamp, and a microwave excimer lamp. Among these, it is preferable to use ultraviolet rays (UV) as the active energy rays.
The active energy ray is preferably irradiated in an inert gas atmosphere such as nitrogen gas or carbon dioxide gas or an atmosphere in which the oxygen concentration is reduced, but can be sufficiently cured even in a normal air atmosphere. The irradiation temperature is preferably 10 to 200 ° C., and the irradiation time is preferably 10 seconds to 10 minutes. Integrated light quantity is generally preferably 1,000~20,000mJ / cm ^2, more preferably 1,000~10,000mJ / cm ^2.

[Physical properties of elastomer composition]
Moreover, since the hardness of the elastomer composition after irradiation of the active energy ray of this invention is determined according to the physical property calculated | required by the use, it is not specifically limited, Preferably it is 30-70 degree | times. Moreover, the breaking strength (Tb) of the elastomer composition after curing is not particularly limited, but is preferably 10 MPa or more, and more preferably 10 to 20 MPa. The elongation at break (Eb) of the elastomer composition after curing is not particularly limited, but is preferably 200% or more, more preferably 300 to 900%.
In addition, all were measured by the method as described in an Example.

[Application of elastomer composition]
The elastomer composition of the present invention can be used in a wide range of applications, for example, sealing materials, sealing materials such as electronic parts, gasket materials, vibration-proof materials, shock absorbing materials, cover materials (for example, ink ink covering agents for ink jet printers), buffer materials, It can be used for applications such as acoustic members (for example, speaker edges), liquid channels or gas channels (for example, refrigerant transport tubes, gas transport tubes, chemical tubes, medical tubes, beverage transport tubes). . Among these, since the elastomer composition of the present invention has a high water vapor barrier property and high mechanical strength, it is suitable for use as a sealing material.

  EXAMPLES Next, although an Example demonstrates this invention still in detail, this invention is not limited at all by these examples.

<Manufacture of the manufacture example 1 acryloyl group containing hydrogenated SBR>
After adding 1 mol of 1,3- (diisopropenyl) benzene to a fully dehydrated and purified cyclohexane solvent, 2 mol of triethylamine and 2 mol of sec-butyllithium are sequentially added and stirred at 50 ° C. for 2 hours. A dilithium polymerization initiator was prepared.
In a 7 liter polymerization reactor purged with argon, 1.90 kg of dehydrated purified cyclohexane, 2.00 kg of hexane solution of 1,2.9 butadiene monomer of 22.9% by mass, and 0% of cyclohexane solution of 20.0% by mass of styrene monomer were added. After adding 130.4 ml of hexane solution of 2,765-1.6 mol / liter of 2,2-di (tetrahydrofuryl) propane, 108.0 ml of 0.5 mol / liter dilithium polymerization initiator was added for polymerization. Was started.
Polymerization was carried out for 1.5 hours while raising the temperature of the polymerization reactor to 50 ° C., then 108.0 ml of a 1 mol / liter ethylene oxide cyclohexane solution was added, and the mixture was further stirred for 2 hours, and then 50 ml of isopropyl alcohol was added. did. A hexane solution of the copolymer was precipitated in isopropyl alcohol and sufficiently dried to obtain a copolymer polyol. This copolymer polyol was a OH group styrene-butadiene copolymer at both terminals, the styrene content was 25% by mass, the weight average molecular weight was 14,500, and the molecular weight distribution was 1.20.

Next, 120 g of copolymer polyol was dissolved in 1 liter of hexane that had been sufficiently dehydrated and purified, and then nickel naphthenate, triethylaluminum, and butadiene prepared in separate containers in a 1: 3: 3 (molar ratio) ratio. The catalyst solution was charged so that the amount of nickel was 1 mol with respect to 1,000 mol of the butadiene portion in the copolymer solution. Hydrogen was added under pressure to 27,580 hPa (400 psi) in a sealed reaction vessel, and a hydrogenation reaction was performed at 110 ° C. for 4 hours. Thereafter, the catalyst residue was extracted and separated with hydrochloric acid of 3N concentration, and further centrifuged to separate the catalyst residue by sedimentation. Thereafter, the hydrogenated copolymer polyol was precipitated in isopropyl alcohol and further sufficiently dried.
100 g of the fully dried hydrogenated copolymer polyol was dissolved in cyclohexane, and 2-acryloyloxyethyl isocyanate (manufactured by Showa Denko KK: Karenz AOI) was slowly added dropwise while maintaining the temperature at 40 ° C. and sufficiently stirring. Thereafter, the mixture was further stirred for 4 hours, precipitated in isopropyl alcohol and dried. The amount of 2-acryloyloxyethyl isocyanate added was 2.49 g. As described above, an acryloyl group-containing hydrogenated styrene-butadiene copolymer (hydrogenated SBR) was obtained from the hydrogenated copolymer polyol.

<Examples 1-7, Comparative Examples 1-4>
In Examples 1 to 7 and Comparative Examples 1 to 4, elastomer compositions having the blending amounts (unit: parts by mass) shown in Table 1 were prepared. Using the composition or the test piece prepared thereby, moisture permeability, hardness, breaking strength and breaking elongation were measured and evaluated according to the following methods.

(1) Moisture permeability The elastomer composition was formed into a film with a thickness of about 1 mm by a coater and cured under the above-mentioned ultraviolet irradiation conditions. Using this cured product, in accordance with JIS Z0208, the moisture permeability was measured under the conditions of 60 ° C. and 90% relative humidity by the cup method, and used as a moisture permeability index.
(2) Hardness With three test pieces having a thickness of 2 mm stacked, the hardness was measured in accordance with JIS K6253 (type A durometer).
(3) Breaking strength, breaking elongation According to “JIS K6251 vulcanized rubber and thermoplastic rubber-Determination of tensile properties”, a DIN No. 3 dumbbell-shaped sample with a thickness of 2 mm was used, and at 23 ° C., a tensile rate of 200 mm / min. Measured with The tensile stress at the time of cutting was defined as the breaking strength (Tb), and the elongation at the time of cutting was defined as the breaking elongation (Eb).

1): Acrylyl group-containing hydrogenated SBR obtained in Production Example 1
2): Sartomer, CN9014 (hydrogenated butadiene homopolymer (BR), weight average molecular weight Mw = 7000)
3): Isobornyl acrylate (Osaka Organic Chemical Co., Ltd.)
4): Styrene-isobutylene-styrene block copolymer (weight average molecular weight Mw = about 70,000, styrene block content 30% by mass)

  As shown in Table 1, it can be seen that the elastomer composition of the present invention has high water vapor barrier properties (moisture permeability), and further has high breaking strength and breaking elongation.

  The elastomer composition of the present invention can be used in a wide range of applications, for example, sealing materials, sealing materials such as electronic parts, gasket materials, vibration-proof materials, shock absorbing materials, cover materials (for example, ink ink covering agents for ink jet printers), buffer materials, It can be used for applications such as acoustic members (for example, speaker edges), liquid channels or gas channels (for example, refrigerant transport tubes, gas transport tubes, chemical tubes, medical tubes, beverage transport tubes). . Among these, since the elastomer composition of the present invention has a high water vapor barrier property and high mechanical strength, it is suitable for use as a sealing material.

Claims (7)

  (A) It contains 100 parts by mass of a curable resin containing at least a hydrogenated conjugated diene (co) polymer having a (meth) acryloyl group, and (B) 10 to 100 parts by mass of a polystyrene-based thermoplastic elastomer. An elastomer composition.   The component (B) includes styrene-isobutylene-styrene block copolymer (SIBS), styrene-butadiene-styrene block copolymer (SBS), styrene-ethylene / butylene-styrene block copolymer (SEBS), and styrene. The elastomer composition according to claim 1, which is at least one selected from ethylene / propylene block copolymers (SEPS).   The elastomer composition according to claim 1 or 2, wherein the component (B) has a weight average molecular weight of 50,000 or more.   The hydrogenated conjugated diene (co) polymer having the (meth) acryloyl group is a hydrogenated styrene-butadiene copolymer or a hydrogenated butadiene homopolymer having a (meth) acryloyl group. The elastomer composition according to any one of the above.   The elastomer composition according to any one of claims 1 to 4, further comprising a (meth) acrylate monomer as the curable resin (A).   The elastomer composition obtained by irradiating an active energy ray to the elastomer composition in any one of Claims 1-5.   The elastomer composition according to any one of claims 1 to 5, which is used for a sealing material.