JP2002038116A - Hot-melt type sealing material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a hot-melt type sealing material having excellent adhesiveness, heat resistance and flexibility and excellent sealability and facilitating the recycling of a material to be bonded. SOLUTION: This hot-melt type sealing material is characterized by having <=35% compression set at 70 deg.C for 22 hours (JIS K6301) and <=5 hardness at 25 deg.C (JIS K6301). A sealing material comprising a styrene-graft copolymer (ratio of styrene/ethylene-butylene of 13/87 wt.%) of a styrene-ethylene-butylene-styrene block copolymer (hydrogenated substance), a polybutene and a hydrogenated petroleum resin is exemplified.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a hot-melt type sealing material. More specifically, a hot-melt sealing material (hereinafter, referred to as a hot-melt sealing material) that can be suitably used particularly for adhesive seals of lamps for vehicles and the like, and that allows easy recycling of adherends.
It may be simply referred to as "seal material". ).

[0002]

2. Description of the Related Art Conventionally, butyl rubber, styrene-ethylene-butylene-styrene block copolymer has been used as a sealing material for adhesively sealing a lens portion and a housing portion of a lamp for a vehicle, a ship, an aircraft, a lighting device and the like. There are known those obtained by adding a tackifier, a plasticizer, a filler, and the like to a commercially available rubber-based polymer such as
-188183 and JP-A-6-313159).

[0003]

However, the conventional sealing material has a problem that the adhesion at high temperatures required for the sealing material is not satisfactory. Recently, there has been a demand for a structure that can be completely recycled including plastics. For example, in a head or rear combination lamp of an automobile, a lens material and a housing portion are completely sealed when used, and a seal material that can be easily disassembled at the time of recycling and is easily peelable is required. However, there has been a problem that conventional sealing materials are not satisfactory.

[0004]

The present inventors have intensively studied to solve these problems and obtain a sealing material excellent in adhesion and dismantling during recycling of adherends. Reached. That is, the present invention relates to a method at 70 ° C., 2
35% 2 hours compression set (JIS K6301)
And hardness at 20 ° C. (JIS K63
01) is 5 or less, and a lamp in which a lens portion and a housing portion are adhesively sealed with the sealing material.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The compression set of the sealing material of the present invention is usually 35% or less, preferably 3% at 70 ° C. for 22 hours.
0% or less, more preferably 25% or less. By setting the compression set within this range, rubber elasticity at high temperatures can be maintained, so that even when the lens portion and the housing portion are pressure-sealed, the sealing material does not undergo plastic deformation under a high-temperature atmosphere. Good adhesion is obtained. The compression set referred to in the present invention is synonymous with “compression set” defined in JIS K6301 (1975, pp. 23-24), and refers to residual strain due to heat compression. Also,
The hardness at 20 ° C. of the sealing material of the present invention is usually 5 or less, preferably 4 or less, and more preferably 3 or less. By setting the hardness within this range, the sealing material can be easily detached and attached at room temperature. The hardness referred to in the present invention is JIS K
6301 (1975, 7-8 pages, spring type A
This is synonymous with "hardness" specified in (Shape).

The sealing material of the present invention comprises a styrene-diene copolymer or a hydrogenated product thereof (a1) and a polymerizable monomer (a2).
And a rubbery polymer (A) obtained by a graft reaction. As the above (a1), for example, styrene-butadiene-styrene block copolymer rubber (SB
S), styrene-isoprene-styrene block copolymer rubber (SIS), styrene-butadiene random copolymer rubber (SBR), and hydrogenated products obtained by partially or entirely hydrogenating the diene portion of these diene copolymer rubbers [ Styrene-ethylene-propylene-styrene block copolymer rubber (SEPS; hydrogenated SIS), styrene-ethylene-butylene-styrene block copolymer rubber (SEBS;
Hydrogenated SBS), hydrogenated SBR, etc.].
Preferred among these are hydrogenated styrene-diene copolymers, and particularly preferred are those having a styrene content of 10 to 45% by weight, based on the total weight of the copolymer.
EPS and SEBS. The number average molecular weight of the (a1) [gel permeation chromatography (GP
C) According to the method. Hereinafter the same) is usually 30,000 to 50
0000, preferably 50,000 to 350,000
It is.

The polymerizable monomer (a2) used for the graft reaction to the above (a1) includes an aromatic vinyl hydrocarbon having 8 to 14 carbon atoms (a21), an amino group-containing vinyl monomer (a22), epoxy Group-containing vinyl monomer (a2
3) a carboxyl group-containing vinyl monomer (a24);
A hydroxyl group-containing vinyl monomer (a25), an amide group-containing vinyl monomer (a26) and a mixture of two or more thereof can be used. (A21) As styrene, α-methylstyrene, vinyltoluene, 2,4-dimethylstyrene, ethylstyrene, isopropylstyrene, butylstyrene, phenylstyrene, cyclohexylstyrene, benzylstyrene, crotylbenzene, vinylnaphthalene, divinylbenzene , Divinyltoluene, divinylxylene, trivinylbenzene and the like. As (a22), aminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, t-
Butylaminoethyl methacrylate, N-aminoethyl (meth) acrylamide, (meth) allylamine, morpholinoethyl (meth) acrylate, 4-vinylpyridine, 2-vinylpyridine, crotylamine, N, N-dimethylaminostyrene, methyl α-acetate Amino acrylate, vinyl imidazole, N-vinyl pyrrole, N
-Vinylthiopyrrolidone, N-allylphenylenediamine and the like. Examples of (a23) include glycidyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, p-vinylphenylphenyl oxide and the like. (A24) includes (meth) acrylic acid, crotonic acid, cinnamic acid, (anhydrous) non (anhydrous) maleic acid, fumaric acid, (anhydrous) itaconic acid, (anhydrous) citraconic acid, and unsaturated dicarboxylic acids thereof. (E.g., monoalkyl (C1-C12) esters). (A
25) include hydroxystyrene, N-methylol (meth) acrylamide, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, polyethylene glycol (degree of polymerization 2 to 10) mono (meth) acrylate, (meth) allyl alcohol , Crotyl alcohol, isocrotyl alcohol, 1-buten-3-ol, 2-buten-1-ol, 2-buten-1,4-diol, propargyl alcohol, 2-hydroxyethylpropenyl ether, sucrose allyl ether, etc. Is mentioned. (A26) includes (meth) acrylamide, N-methyl (meth) acrylamide, N-
Butyl acrylamide, diacetone acrylamide, N
-Methylol (meth) acrylamide, N, N'-methylene-bis (meth) acrylamide, cinnamamide,
N, N-dimethylacrylamide, N, N-dibenzylacrylamide, methacrylformamide, N-methyl N-vinylacetamide, N-vinylpyrrolidone and the like can be mentioned. Of these, (a21) and (a24) are preferred, and styrene and methacrylic acid are particularly preferred.

The rubbery polymer (A) comprises (a1) and (a)
2) can be obtained by a graft reaction with a known method such as a solution polymerization method or a bulk polymerization method. (A)
The production method of is not particularly limited, for example, the following (1),
The method (2) can be exemplified.

(1) Add (a1) to a solvent, dissolve or swell under heating, and add monomer (a) in the presence of a polymerization initiator.
2) is supplied continuously or intermittently, and after completion of the polymerization, the solvent and, if necessary, unreacted monomers are distilled off under normal pressure or reduced pressure to obtain a rubbery polymer (A) (solution polymerization method). The solvent is not particularly limited as long as it dissolves or swells the raw material and the reaction product, but has a boiling point of 30 to 200.
° C is preferred. Specific examples include aromatic hydrocarbon solvents (toluene, xylene, ethylbenzene, cumene, etc.), aliphatic hydrocarbon solvents (n-hexane, n-octane, n-decane, etc.), alicyclic hydrocarbon solvents (Cyclohexane, methylcyclohexane, cyclopentane, etc.), halogen solvents (chloroform, carbon tetrachloride, dichloroethane, etc.), ketone solvents (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.), ether solvents (dioxane, dibenzyl) Ether, diethyl ether) and ester solvents (ethyl acetate, isopropyl acetate, butyl acetate) and the like. Preferred are aromatic hydrocarbon solvents, especially toluene and xylene. The solution polymerization temperature is usually in the range of 80 to 240 ° C., and can be appropriately selected depending on the type and amount of the polymerization initiator used and the desired molecular weight. The temperature at which the solvent and, if necessary, the unreacted monomer are distilled off depends on the type of the solvent or monomer to be distilled off.
00 to 200 ° C.

(2) A solution prepared by dissolving (A) previously obtained by a graft reaction as a compatibilizer component in an amount not exceeding 10% by weight based on (a2), or (a2),
1) and a polymerization initiator were added, and the mixture was heated and polymerized.
If necessary, unreacted monomers are distilled off under normal pressure or reduced pressure to obtain a rubbery polymer (A) (bulk polymerization method). The polymerization temperature, unreacted monomer distillation conditions, and the like in the polymerization are the same as those in the solution polymerization of (1). Among these methods, the polymerization method (1) is preferable from the viewpoint of obtaining good compatibility.

The amount of (a2) used in the graft reaction is usually 10 to 500% by weight, preferably 50 to 200% by weight, based on the weight of (a1). Also,
The graft ratio of (a2) in (A) [that is, (a)
(A) of the (co) polymers involved in the graft reaction (a)
Weight ratio of (co) polymer of 2)] is usually 2 to 20%, preferably 5 to 15% from the viewpoint of heat resistance and coatability. The graft ratio is a value obtained from the following equation. [Weight of (co) polymer of (a2) grafted to (a1)] x 100 / [total weight of (co) polymer of (a2) contained in (A)] Specific measuring method of graft ratio For example, (a
When 1) is SEBS and (a2) is styrene, SEBS grafted with styrene is insoluble in xylene (swelled state)
Since the homopolymer (polystyrene) of SEBS and styrene is soluble in xylene, the polystyrene (including unreacted styrene) in the xylene-soluble matter when the xylene solution (dispersion) of (A) is filtered ) Is measured (for example, GPC method), the amount of styrene involved in the graft is calculated from the amount of styrene charged, and the graft ratio is determined from the above equation. That is, the preferred solvent used in the production of (A) is (a1), (a2) and the (co) polymer of (a2) alone, but (a1)
And (a2) are insoluble solvents, and (a)
It can be appropriately selected depending on the types of 1) and (a2).

In the graft reaction of the present invention, a known polymerization initiator can be used if necessary. Examples of the polymerization initiator include benzoyl peroxide, lauroyl peroxide, dibenzoyl peroxide, dichlorobenzoyl peroxide, t-butylperoxy-tri-methylhexanate, di-t-butyl peroxide, and dicumyl peroxide. Organic peroxides such as oxide, cumene hydroperoxide, methyl isobutyl ketone hydroperoxide, bis (4-t-butylcyclohexyl) peroxydicarbonate, persuccinic acid, peroxyketal; 2,2'-azobisiso Butyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (2-methylbutyronitrile), 1,1′-azobis (cyclohexane-1-alkonitrile), 2,2′-azobis (2,2′-azobis
4,4-trimethylpentane), dimethyl 2,2′-azobis (2-methylpropionate), 2,2′-azobis [2- (hydroxymethyl) propionitrile] and 1,1′-azobis (1 Azo compounds such as -acetoxy-1-phenylethane); and combinations of two or more of these. As the polymerization initiator, it is particularly preferable to appropriately select and use one that is easily dissolved in (a2). The amount of the polymerization initiator to be used is usually 0.0
It is 5 to 5% by weight, preferably 0.1 to 2% by weight.

(A) is (a2) [(a22) to (a2)
6)] and may be intermolecularly crosslinked via a substituent moiety derived from [6]). As a method of intermolecularly crosslinking (A),
A method of dissolving a sealing material containing (A) in a solvent and supplying a crosslinking agent in the presence of a catalyst, or a method of producing a sealing material containing (A) without removing the solvent and continuously removing the solvent. A method of supplying a cross-linking agent underneath is exemplified. The amount of the cross-linking agent used is preferably 0.5 to 6 functional group equivalents per substituent of (a2) of the sealing material containing (A) from the viewpoint of heat resistance and coatability.

When a cross-linking agent is used, the cross-linking agent may be a divalent to a tetravalent group which can react with a substituent derived from (a2).
Those containing a valent reactive group can be used. Specific examples include polyamines [aliphatic diamines having 2 to 12 carbon atoms (ethylenediamine, hexamethylenediamine, etc.), alicyclic diamines having 6 to 15 carbon atoms (diaminocyclohexane, isophoronediamine, 4,4′-diaminocyclohexyl) Methane, etc.), aromatic diamines having 6 to 15 carbon atoms (aniline, toluenediamine, xylylenediamine,
Polyols [dihydric alcohol [aliphatic 2], 4,4'-diaminodiphenylmethane, etc.), polyalkylene (C2-4) polyamine (diethylenetriamine, etc.), etc.
Polyhydric alcohols (ethylene glycol, diethylene glycol, propylene glycol, 1,4-butanediol, hexamethylene glycol, etc.), alicyclic dihydric alcohols (dihydroxycyclohexane, etc.), aromatic ring-containing 2
Dihydric alcohol (xylylene glycol, dihydroxyethylbenzene, oxyalkylene ether of bisphenol A, etc.), trihydric alcohol [glycerin, trimethylolpropane, trialkanolamine (triethanolamine, etc.)], tetrahydric alcohol [pentaerythritol, Polyepoxides (di-, tri- and tetraglycidyl ethers of the above polyols, ethylene glycol bisepoxydicyclopentyl ether, bisphenol A diglycidyl) Ethers, etc.); polyisocyanates [aromatic diisocyanates (4,4'-diphenylmethane diisocyanate, tolylene diisocyanate, etc.), aliphatic diisocyanates (hexamethylene) Diisocyanate, lysine diisocyanate, etc.), alicyclic diisocyanate (isophorone diisocyanate, 4,4'-diisocyanatocyclohexylmethane, etc.), araliphatic diisocyanate (xylylene diisocyanate, etc.), etc.]. These crosslinking agents are appropriately selected depending on the type of the substituent derived from (a2). For example, when the substituent is an amino group or a carboxyl group, a polyepoxide is preferable, and when the substituent is a hydroxyl group or an amide group, a polyisocyanate is preferable. In the case of an epoxy group, polyamines are preferred.
As the solvent used at the time of crosslinking, the same solvents as those exemplified in the production of (A) can be used. The reaction temperature is usually in the range of 80 to 240 ° C., and the temperature at which the solvent is distilled off is:
Although it depends on the solvent to be distilled off, it is usually 100 to 200 ° C.
It is.

The sealing material of the present invention can be obtained by further adding a plasticizer (B) and a tackifier (C) to the rubbery polymer (A).

Examples of the plasticizer (B) include the following (1) to (5). (1) Paraffinic, naphthenic or aromatic process oil [kinematic viscosity (100 ° C.) = 1 to 100 [mm]
² / s], preferably 3 to 60 [mm ² / s]] For example,
As a paraffinic oil, "Diana Process Oil PW-380" manufactured by Idemitsu Kosan Co., Ltd. ｛Kinematic viscosity (100 ° C.); 30.10 [mm ² / s], aniline point: 144.0 ° C., viscosity Index; 110 °, etc.,
As the naphthenic oil, “Diana Process Oy NS-100” manufactured by Idemitsu Kosan Co., Ltd. ｛Kinematic viscosity (1
9.948 [mm ² / s], aniline point: 1
06.2 ° C., viscosity index: 68 °, and the like. As the aromatic process oil, Idemitsu Kosan Co., Ltd. “Product name:
Diana Process Oil AC-460 ”｛Kinematic viscosity (10
0 ° C); 12.11 [mm ² / s], aniline point;
0.0 ° C., viscosity index; (2) Liquid resins such as liquid polybutene, liquid polybutadiene and liquid polyisoprene (number average molecular weight = 200 to
5,000, preferably 300-1,000)
As the liquid polybutene, “Nisseki Polybutene LV-100” manufactured by Nisseki Mitsubishi Chemical Co., Ltd. ｛number average molecular weight: 5
00, kinematic viscosity (100 ° C.); 14, pour point;
° C｝ and the like. (3) Hydrogenated product of the above (2) (4) Natural or synthetic wax [paraffin wax, microcrystalline wax, low molecular weight polyolefin wax (Mw = 1,000-30,000), etc.] For example, as paraffin wax, Nippon Seiro Co., Ltd. “Paraffin Wax 155” Melting point: 69
° C, kinematic viscosity (100 ° C); 6.4 [mm ² / s]} and the like. (5) Mixture of two or more of these Preferred among these are (1) and (2) from the viewpoint of compatibility, more preferably a paraffinic process oil and liquid polybutene, particularly preferably liquid polybutene It is.

Examples of the tackifier (C) include rosin resin, terpene resin, cumarone-indene resin, petroleum resin [C5 fraction, C9 fraction, C5 / C9 fraction, dicyclopentadiene, etc. Polymer], a phenol resin, a xylene resin, and one or more resins selected from hydrogenated products thereof. Of these, hydrogenated terpene resins and hydrogenated petroleum resins are preferred in terms of thermal stability, odor and hue, and particularly preferred are hydrogenated petroleum resins.

The method for producing the sealing material containing (A), (B) and (C) is not particularly limited, and examples thereof include the following methods (1) and (2).

(1) A solvent, (a1), a plasticizer (B) and a tackifier (C) are dissolved by heating, and a monomer (a2) is continuously or intermittently supplied in the presence of a polymerization initiator. After completion of the polymerization, the solvent and, if necessary, the unreacted monomer are distilled off under normal pressure or reduced pressure to obtain a sealing material containing the rubbery polymer (A) (coexisting solution polymerization method). The polymerization temperature, unreacted monomer distillation conditions, and the like in the polymerization are the same as those in the solution polymerization described above. In addition, (B) and (C) may be added and mixed to the solution of (A) obtained in advance.

(2) A solution in which (A) obtained by graft polymerization in advance does not exceed 10% by weight based on (a2) as a compatibilizer component, or (a2),
1), (B), (C) and a polymerization initiator are added, and after heating and polymerizing, unreacted monomers are distilled off at normal pressure or reduced pressure as necessary to obtain (A), (B) And a sealing material containing (C) (coexisting bulk polymerization method). The polymerization temperature, unreacted monomer distillation conditions, and the like in the polymerization are the same as the bulk polymerization conditions described above.

The content of (A) relative to the total weight of (A), (B) and (C) in the sealing material is usually 5 to 4
5% by weight, preferably 10 to 25% by weight, (B)
Is usually 20 to 60% by weight, preferably 40 to 60% by weight.
% By weight, and the content of (C) is usually 10 to 40% by weight,
Preferably it is 20 to 30% by weight. When the content of (A) is in this range, the sealing material can have a suitable cohesive force, which is more preferable in terms of the workability and hardness of the sealing material. When the content of (B) is within this range, the compatibility of each component,
It is more preferable in terms of the cohesive force of the sealing material, and bleeding is less likely to occur. When the content of (C) is in this range, it is more preferable in terms of adhesive strength and hardness of the sealing material.

The melting temperature of the sealing material when applied to an adherend is usually 100 to 200 ° C. Further, the melt viscosity of the sealant at 190 ° C. is preferably from 5,000 to 1,000,000 mPa · s, more preferably from 10,000 to 200,000 mPa · s, from the viewpoint of coatability.
s.

The sealing material of the present invention contains, if necessary, known additives (antioxidants, ultraviolet absorbers, light stabilizers, adsorbents, organic or inorganic fillers, pigments, dyes, fragrances, etc.). Can be done. Examples of the antioxidant include hindered phenol compounds [for example, pentaerythyl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], octadecyl-3-
(3,5-di-t-butyl-4-hydroxyphenyl)
Propionate, etc.], phosphorus compounds [eg, tris (2,4-di-t-butylphenyl) phosphite etc.], sulfur compounds [eg, pentaerythyl-tetrakis (3-laurylthiopropionate), dilauryl-3] , 3'-thiodipropionate, etc.]. Examples of ultraviolet absorbers include benzotriazole compounds [eg, 2- (3,5-di-t-amyl-2-hydroxyphenyl) benzotriazole, 2- (5-methyl-2-hydroxyphenyl) benzotriazole, etc.] Is raised. Examples of the light stabilizer include hindered amine compounds [eg, (bis-2,2,6,6-tetramethyl-4-piperidyl) sebacate and the like]. Examples of the adsorbent include alumina, silica gel, molecular sieve and the like. Examples of the organic or inorganic filler include calcium carbonate, magnesium carbonate, and alumina. Examples of the pigment include titanium oxide, carbon black, and the like.As the dye, a basic dye,
Acid dyes and the like. Examples of the flavor include limonene and ethyl caprylate. The amount of each of these additives is usually 10% by weight or less, preferably 0.1 to 5% by weight, based on the weight of the sealing material containing (A). The additive can be added at (A) or at any stage in the production of the sealing material.

The sealing material of the present invention is excellent in adhesion, flexibility and heat resistance, and therefore has sufficient followability to deformation of an adherend in a high-temperature atmosphere. Since it is excellent in holding property, it is extremely effective for adhesion of a base material from which a sealing material can be easily peeled off, especially for adhesive sealing between a lens portion and a housing portion of a headlight or a sign lamp of a vehicle. In other words, when used as an adhesive seal for vehicular lamps, a seal is applied during normal assembly, fixed with a jig at several places after crimping, but conventional seals cause plastic deformation in a high-temperature atmosphere, so airtightness is reduced. It was difficult to secure. On the other hand, the sealing material of the present invention is excellent in flexibility and heat resistance (hardness is 5 or less, and compression set at 70 ° C. for 22 hours is 35% or less). However, it can follow without plastic deformation and can secure airtightness. Further, once the jig is removed, since the cohesive force is strong, the jig can be easily peeled off without leaving the sealing material at the interface with the adherend. Therefore, recycling of the adherend becomes extremely easy.

The sealing material of the present invention is excellent in adhesion, cohesion, flexibility, plasticizer retention and processability, and therefore can be used for a wide range of adherends (for example, various plastic molded articles, rubber, paper,
Cloth, metal, wood, glass, mortar concrete, etc.)
However, it is particularly suitable as a sealant for bonding polyolefin (polyethylene, polypropylene, etc.) resin molded articles having poor adhesion to each other or to adhere these to other adherends. Furthermore, since it is extremely effective in adhering a heat-resistant and deformable base material to a substrate, it is particularly suitable for an adhesive seal between a lens portion of a vehicle headlight and a lens portion of a vehicle headlight or a sign lamp and a housing portion. Can be used.

Examples of the method of applying the sealing material of the present invention to an adherend include methods such as spiral coating, bead coating, roll coating, and slot coating, but are not limited thereto. Absent.

The sealing material of the present invention can be used as a hot-melt type sealing material, an organic solvent solution type, an emulsion type, a dispersion type, a sheet type and the like. Preferably, it is a hot melt type sealing material.

[0028]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. In addition, the part in an Example shows a weight part and% shows weight%.

(Description of Abbreviations) SEBS1651; hydrogenated styrene-ethylene-butylene-styrene block copolymer [St / EB ratio w
t% = 33/67, "Clayton G" manufactured by Shell Chemical Co., Ltd.
-1651 ", solution viscosity (10 wt% toluene solution)
1,000 mPa · s / 25 ° C.] SEPS2043; styrene-ethylene-propylene-
Hydrogenated styrene block copolymer [St / EP ratio wt% = 13/87, “Septon 204” manufactured by Kuraray Co., Ltd.
3 ", solution viscosity (20 wt% toluene solution) 720 mP
a · s / 30 ° C.] polybutene; liquid polybutene [Nippon Petrochemical Co., Ltd. “Polybutene LV-100” pour point-32.5] PW380; paraffinic process oil [Idemitsu Kosan Co., Ltd. “Diana Process Oil PW” -380 "{Kinematic viscosity (100 ° C); 30.10 [mm ² / s], aniline point: 144.0 ° C, viscosity index: 110 °] Imarb; Hydrogenated petroleum resin [C5 / C6 fraction copolymer] Main component, manufactured by Idemitsu Petrochemical Co., Ltd., "I-MARV P-13
0 "softening point 130 ° C] ST; styrene monomer MAA; methacrylic acid epoxide; bisphenol A diglycidyl ether [Glycier BPP-35 manufactured by Sanyo Chemical Industries, Ltd.
0 "] Amine;" DABCO TMR-3 "manufactured by Air Products
Adeca; Asahi Denka Kogyo Co., Ltd. "Adeka Stub PEP-3"
6 "Irga;" Irganox 1010 "manufactured by Ciba Geigy DTBP; polymerization initiator [di-t-butyl peroxide]

Example 1 A pressurized reaction vessel equipped with a heating and stirring device and a dropping funnel was placed
After 233 parts of xylene and 111 parts of SEBS1651 were charged and the inside of the container was replaced with nitrogen, the temperature was raised to 160 ° C. in a sealed state. At this temperature, 100 parts of ST containing 0.8 parts of DTBP was added dropwise over 120 minutes, and 160 ° C.
For 90 minutes to perform a graft polymerization reaction to obtain a rubbery polymer (A1). The end point of the reaction is the disappearance of the monomer by gas chromatography (GC) and the change in the number average molecular weight (Mn) by the GPC method (SEBS165 before the reaction).
Part of the peak of Mn 250,000 was 400,000.
(Shift to 0). ST graft ratio [the (A
The amount of polystyrene in the filtrate obtained by filtering the solution of 1) (GPC
Method). The same applies hereinafter) was 12.5%. Then, 556 parts of polybutene and Imarb 333
Parts and 5 parts of Adeka and 5 parts of Irga as antioxidants were added and uniformly mixed at 150 ° C. for 2 hours. Xylene was distilled off from the generated polymer solution (150 ° C., 5 mmHg) to obtain a sealing material 1 of the present invention. The end point of xylene distillation is G
It was confirmed by disappearance of xylene by C.

Example 2 Into the same reaction vessel as in Example 1, 233 parts of xylene and 111 parts of SEPS2043 were charged, the inside of the vessel was replaced with nitrogen, and the temperature was raised to 160 ° C. in a sealed state. At this temperature, 100 parts of ST containing 0.8 parts of DTBP was added dropwise over 120 minutes, and the mixture was kept at 160 ° C. for 90 minutes to carry out a graft polymerization reaction to obtain a rubbery polymer (A2). The end point of the reaction is the disappearance of the monomer by GC, GPC
(Mn18 of SEPS2043 before reaction)
(Some of the 0000 peak shifts to 250,000)
Confirmed from. The graft ratio of ST was 9.5%.
Then, 556 parts of polybutene and 333 parts of Iamarb and 5 parts of Adeka and 5 parts of Irga as an antioxidant were added,
The mixture was uniformly mixed at 150 ° C. for 2 hours. Xylene was distilled off from the generated polymer solution (150 ° C., 5 mmHg) to obtain a sealing material 2 of the present invention. The end point of the distillation of xylene was confirmed by disappearance of xylene by GC.

Example 3 A sealing material 3 of the present invention was obtained in the same manner as in Example 1 except that the same amount of PW380 was used instead of polybutene.

Example 4 A sealing material 4 of the present invention was obtained in the same manner as in Example 1 except that a mixture of 30 parts of ST and 70 parts of MAA was used instead of 100 parts of ST as a monomer.

Example 5 200 parts of xylene was added to 100 parts of the sealing material obtained in the same manner as in Example 1 except that a mixture of 75 parts of ST and 25 parts of MAA was used instead of 100 parts of ST as the monomer. The mixture was uniformly mixed at 140 ° C., and 10 parts of epoxide and 3.3 parts of amine as a catalyst were added to
The reaction was performed at 0 ° C. for 2 hours. Xylene was distilled off (150 ° C., 5 mmHg) from the obtained crosslinked product to obtain a sealing material 5 of the present invention. The end point of the distillation of xylene was confirmed by disappearance of xylene by GC.

COMPARATIVE EXAMPLE 1 233 parts of xylene, 111 parts of SEBS1651, 556 parts of polybutene and 333 parts of Iamarb, 5 parts of Adeka and 5 parts of Irga as antioxidants were added.
The mixture was uniformly mixed at 0 ° C. for 3 hours. Xylene was distilled off (150 ° C., 5 mmHg) from the obtained product to obtain a comparative sealing material ratio of 1. The end point of the distillation of xylene was confirmed by disappearance of xylene by GC.

Comparative Example 2 A comparative sealing material ratio of 2 was obtained in the same manner as in Example 1 except that polybutene was changed from 556 parts to 778 parts and eyemarb was changed from 333 parts to 111 parts.

Comparative Example 3 In Example 1, SEBS1651 was changed from 111 parts to 4 parts.
A comparative sealing material ratio of 3 was obtained in the same manner as in Example 1 except that 90 parts, polybutene was changed from 556 parts to 80 parts, and eyemarb was changed from 333 parts to 430 parts.

Table 1 shows the composition ratio (% by weight) of the sealing materials of Examples 1 to 5 and Comparative Examples 1 to 3.

[0039]

[Table 1]

Performance Test Example Seal material 1 obtained in Examples 1 to 5 and Comparative Examples 1 to 3
The melt viscosity, compression set, hardness, adhesion, and disassembly were measured according to the following measurement methods for 5 and ratios 1１〜３3, respectively. Table 2 shows the results.

(Measurement method) Compression set: JIS K6301 (1975,
23 to 24). (70 ° C, 22
Time) Hardness: JIS K6301 (1975, 7-8)
Section, spring type A type). still,
The measurement temperature was 20 ° C., and the scale was read after 5 seconds. Melt viscosity: viscosity measured by a rotational viscometer at 190 ° C. [Tokyo Keiki BH type, rotor No. 7, rotation speed 10
(Seal materials 1, 2, 5, ratio 3), 20 (seal material 3,
4, ratio 1, ratio 2)]. Adhesion: Preparation of test pieces: 3 g of each sealing material was applied to a polycarbonate substrate (thickness 3 mm, length 75 mm, width 50 mm) for 20 minutes.
Apply at 0 ° C. and immediately make a polypropylene substrate (thickness 3 mm, length 75 mm, width 50 m) so that the thickness becomes 1 mm.
m), and then left at room temperature for 24 hours.・ Evaluation method: At a distance of 10 mm from the sealing material, a 3 mm spacer was fitted between the polycarbonate and the polypropylene base material. After leaving at room temperature for 30 days, the state of destruction of the interface of the sealing material near the space where the spacer was fitted was visually observed. Was observed. Disassembly: ・ Preparation of test piece; same as test piece used in adhesion test. -Evaluation method: The state of the base material after peeling off the sealing material adhered to the base material made of polycarbonate and polypropylene by hand was visually checked. Evaluation criteria: ○: no sealing material remains on the substrate. Δ: Part of the sealing material remains on the substrate. X: A large amount of sealing material remains on the base material.

[0042]

[Table 2]

[0043]

The sealing material of the present invention is superior in heat resistance (low compression set) and flexibility (low hardness) as compared with the conventional sealing material. Can be completely sealed without plastic deformation even in a high-temperature atmosphere.However, since the sealing material can be easily removed by removing the fixing between the adherends, Easy to recycle. Because of the above effects, the sealing material of the present invention is extremely useful especially for an adhesive seal between a lens portion and a housing portion of a lamp of a vehicle or the like.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08L 91/00 C08L 91/00 91/06 91/06 101/00 101/00 C09K 3/10 C09K 3 / 10Z F term (reference) 4H017 AA03 AB17 AC02 AD05 AE04 AE05 4J002 AC03X AC06X AC11X AE03X AE05X AF02Y BA01Y BB18X BK00Y BN21W CC03Y CE00Y FD02X FD34Y GJ02 4J0BA BA27 AC16 BA27AC16 BA40 BA42 BA50 DB02 DB09 DB15 FA09 GA08 GA09 4J040 BA182 BA192 BA202 CA042 DA002 DK012 DL131 DL171 DN032 EB022 EB082 HB01 JA12 JB01 KA16 KA26 KA31 LA01 MA02 MA05 MA08 MA09 MA10 MA11 MA12 NA16

Claims (9)

[Claims] 1. Compression set at 70 ° C. for 22 hours (JIS
K6301) is 35% or less, and the hardness at 20 ° C. (JIS K6301) is 5 or less. 2. A rubbery polymer (A) obtained by subjecting a polymerizable monomer (a2) to a graft reaction with a styrene-diene copolymer or its hydrogenated product (a1).
The described sealing material. 3. The sealing material according to claim 2, wherein (a1) is a styrene-butadiene block copolymer, a styrene-isoprene block copolymer and / or a hydrogenated product thereof. 4. A method according to claim 1, wherein (a2) is an aromatic hydrocarbon monomer, and / or
The sealing material according to claim 2 or 3, which is a monomer having at least one substituent selected from the group consisting of an amino group, an epoxy group, a carboxyl group, a hydroxyl group, and an amide group. 5. The sealing material according to claim 4, wherein (A) is a rubbery polymer cross-linked by a molecule through a substituent derived from (a2). 6. A sealing material comprising (A) according to claim 2 and a plasticizer (B) and a tackifier (C). 7. The sealing material according to claim 6, wherein (B) is at least one selected from the following (1) to (3). (1) paraffinic, naphthenic and / or aromatic process oils (2) liquid polybutene, liquid polybutadiene, liquid polyisoprene and / or their hydrides (3) natural and / or synthetic waxes 8. The content of (A) is from 5 to 45% by weight, the content of (B) is from 20 to 60% by weight, and based on the total weight of (A) + (B) + (C), and The content of (C) is 10 to
The sealing material according to claim 6 or 7, which is 40% by weight. 9. The lens unit and the housing unit according to claim 1, wherein:
A lamp which is adhesively sealed with the sealing material according to any one of the above.