JP2007138013A - Double-sided pressure-sensitive adhesive sheet and method for producing member using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an adhesive composition having high adhesive force and excellent high cohesive power, while using an adhesive resin having a low glass transition temperature, and to provide a double sided adhesive sheet which is excellent in adhesive strength to members and in impact resistance due to dropping, and is preferably used for the fixation of electronic equipment parts. <P>SOLUTION: This double sided adhesive sheet having adhesive layers (A) on both the sides of a nonwoven fabric or polyester-based film is characterized in that the adhesive layer (A) is formed from a copolymer (a) which is prepared by copolymerizing 8 to 20 wt.% of iso-butyl methacrylate and one or more other copolymerization monomers, wherein the total amount of the monomers is 100 wt.%, has at least one kind of carboxyl groups and hydroxyl groups, a weight-average mol.wt. of 400,000 to 1,200,000 and a glass transition temperature of -70 to -40°C, and an adhesive (b) containing a cross-linking agent having functional groups capable of reacting with at least one kind of the carboxyl groups and the hydroxyl groups. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a double-sided pressure-sensitive adhesive sheet. Specifically, the present invention relates to a double-sided pressure-sensitive adhesive sheet preferably used for fixing a window member of a display portion of an electronic device.

  Conventionally, double-sided pressure-sensitive adhesive sheets have been used for fixing members in various industrial fields because of their good workability and workability. In particular, it is more advantageous than an adhesive when the member to be fixed has a complicated shape or when productivity in an automated line is required. For this reason, a double-sided pressure-sensitive adhesive sheet is used for fixing a nameplate of an electronic device and a protection panel of an information display unit. Electronic devices, particularly portable electronic devices, are becoming smaller, thinner, and lighter due to technological innovation. Therefore, the use of an adhesive is preferable to the use of screws and screws, but the use of a double-sided pressure-sensitive adhesive sheet is becoming the mainstream in place of an adhesive that requires a drying or heating process. The double-sided pressure-sensitive adhesive sheet is suitably used not only for the production and assembly of the electronic device itself, but also for the production and assembly of a housing for housing the electronic device therein.

  However, as miniaturization, thickness reduction, and weight reduction progress, the double-sided pressure-sensitive adhesive sheet is required to be thin, and the area to be attached is becoming smaller. Generally, the adhesive strength of a double-sided PSA sheet decreases as the thickness decreases or the area of attachment decreases. Therefore, the adhesive strength required for the double-sided pressure-sensitive adhesive sheet has been increasing in recent years. In addition, the portable electronic device is also required to have a physical property that does not drop even when an impact due to dropping is applied, so that the joining member does not fall off even if it is accidentally dropped.

Further, as a physical property required as a double-sided pressure-sensitive adhesive sheet for fixing various members, there is a demand for an adhesive strength that resists the stress and does not fall off even when a stress that deforms the member is applied.
Moreover, in order not to drop out even if an impact due to dropping is applied, it is necessary to lower the glass transition temperature of the adhesive. On the other hand, it is necessary to increase the cohesive force of the pressure-sensitive adhesive layer so that it does not fall off even when a certain stress is applied to the deformation of the member. Therefore, physical properties that have a low glass transition temperature and can exhibit high adhesive strength and cohesive strength are required.

  As a method for improving the adhesive force and cohesive force, for example, a method using a large amount of polar monomer or high cohesive force monomer as a constituent of an acrylic pressure-sensitive adhesive composition, or a method of increasing the amount of tackifying resin added or the amount of curing agent is used. As is known, in these methods, although the adhesive strength to the member is improved, the glass transition temperature of the pressure-sensitive adhesive becomes high, and it easily falls off due to an impact caused by dropping. On the other hand, when the acrylic pressure-sensitive adhesive composition obtained by the reverse method to the above is used, the member does not fall off due to an impact caused by dropping, but the adhesive strength to the member is lowered.

  In contrast to acrylic pressure-sensitive adhesives that are difficult in terms of cohesive force, for example, Patent Document 1 proposes to use polyester having a polycarbonate structure in order to improve the adhesive force and cohesive force of the pressure-sensitive adhesive. Yes. However, with this technique, it has been difficult to achieve both physical properties that the adhesive force and cohesive force can be improved, and that the member does not fall off even when an impact due to dropping is applied.

Patent Document 2 proposes a pressure-sensitive adhesive that uses alkyl methacrylate as a re-peeling adhesive for the purpose of suppressing an increase in peel strength over time, and uses 43 parts by weight of iso-butyl methacrylate in Example 2. ing. However, according to the calculation method of the glass transition temperature described in this specification, the composition of this example is as high as −6.1 ° C., and has low tack and adhesive strength. Adhesive strength is sufficient for re-peeling, but the adhesive layer that constitutes the double-sided adhesive sheet for fixing members requires a low glass transition temperature and requires high adhesive strength. It is not suitable for use.
JP 2000-230164 A JP 2002-363521 A

  The present invention obtains a pressure-sensitive adhesive composition having a high adhesive force and a high cohesive force while using a resin for a pressure-sensitive adhesive having a low glass transition temperature. An object of the present invention is to provide an excellent double-sided pressure-sensitive adhesive sheet preferably used for fixing electronic device components.

1st invention is an adhesive sheet which has an adhesive layer (A) on both surfaces of a nonwoven fabric or a polyester-type film,
The pressure-sensitive adhesive layer (A) is obtained by copolymerizing 8 to 20% by weight of iso-butyl methacrylate and another copolymerizable monomer in 100% by weight of the total amount of monomers, and has at least one of a carboxyl group or a hydroxyl group. And a copolymer having a weight average molecular weight of 400,000 to 1,200,000 and a glass transition temperature of −70 to −40 ° C. and a functional group capable of reacting with at least one of a carboxyl group and a hydroxyl group It is related with the adhesive sheet characterized by being formed from the adhesive (b) containing an agent.

  In the second invention, a frame member (B) having an opening and a window member (C) for covering the opening of the frame member are provided at a position surrounding the opening of the frame member (B). It is related with the member (D) laminated | stacked through the adhesive sheet of 1st invention description.

  3rd invention is a manufacturing method of member (D) as described in the said invention, Comprising: One surface of the adhesive sheet as described in 1st invention is affixed on the peripheral part of window member (C). It is related with the manufacturing method of the member (D) characterized by sticking a window member with a layer so that the opening part of the frame member (B) which has an opening part may be covered.

  ADVANTAGE OF THE INVENTION By this invention, the double-sided adhesive sheet excellent in the high adhesiveness calculated | required by the double-sided adhesive sheet which fixes the window member of the display part of an electronic device, and the impact resistance by dropping can be provided.

The double-sided pressure-sensitive adhesive sheet of the present invention is a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer (A) on both sides of a nonwoven fabric or a polyester film,
The pressure-sensitive adhesive layer (A) is formed from a pressure-sensitive adhesive (b) containing a copolymer (a) containing iso-butyl methacrylate as essential components and a crosslinking agent.

  Iso-butyl methacrylate, which is an essential component of the monomer constituting the copolymer (a) used in the present invention, has a coating film strength of the pressure-sensitive adhesive layer with a small amount of use compared to other acrylic copolymerizable monomers. It is possible to improve. Therefore, by using iso-butyl methacrylate, the cohesive force of the pressure-sensitive adhesive layer can be improved without increasing the glass transition temperature of the copolymer, and the adhesive force and cohesive force can be improved. As a result, it is possible to provide a double-sided adhesive tape excellent in high adhesiveness required for a double-sided pressure-sensitive adhesive sheet for fixing electronic device parts and impact resistance due to dropping.

Even when normal-butyl methacrylate, which is the structural isomer, is used instead of iso-butyl methacrylate, the cohesive force cannot be improved, and a high degree of adhesion cannot be obtained.
Even if iso-butyl acrylate is used in place of iso-butyl methacrylate, the improvement of cohesion cannot be expected.

It is important that the copolymer (a) used in the present invention has at least one of a carboxyl group or a hydroxyl group as a functional group involved in the reaction with a crosslinking agent described later. In order for the copolymer (a) to have at least one of a carboxyl group or a hydroxyl group, a monomer having at least one of a carboxyl group or a hydroxyl group is used as a monomer that can be copolymerized with iso-butyl methacrylate.
Examples of the copolymerizable monomer having at least one of a carboxyl group and a hydroxyl group include alkenyl group-containing compounds, α, β-unsaturated carboxylic acid esters and α, β-unsaturated carboxylic acids having at least one of a carboxyl group and a hydroxyl group. Is mentioned.
Examples of the monomer having at least one carboxyl group in addition to the radical polymerizable unsaturated group include (meth) acrylic acid, itaconic anhydride, itaconic acid, crotonic acid, maleic anhydride, maleic acid, 2- (meta ) Acrylyloxyethyl succinic acid, 2-acryloyloxyethyl phthalic acid, 2- (meth) acryloyloxyethyl hexahydrophthalic acid and the like.
Examples of the monomer having at least one hydroxyl group in addition to the radical polymerizable unsaturated group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate. , 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, (4-hydroxymethylhexyl) -methyl acrylate, chloro- 2-hydroxypropyl (meth) acrylate, diethylene glycol mono (meth) acrylate, caprolactone-modified (meth) acrylates, polyethylene glycol (meth) acrylates, polypropylene glycol (meth) acrylate Relate, and the like can be mentioned.

Examples of other copolymerizable monomers used in obtaining the copolymer (a) used in the present invention include compounds having a polymerizable double bond in the molecule called α, β-unsaturated compound. Acrylic monomers are preferred from the viewpoints of copolymerization with tert-butyl methacrylate and adhesive properties.
For example, methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl acrylate, t- (meth) acrylate Butyl, n-amyl (meth) acrylate, isoamyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, (meth) acrylic acid Alkyl (meth) acrylates such as decyl, dodecyl (meth) acrylate, octadecyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate;
(Meth) acrylic acid cyclic esters such as cyclohexyl (meth) acrylate, benzyl (meth) acrylate, isobornyl (meth) acrylate, phenyl (meth) acrylate, phenoxyethyl (meth) acrylate;
Allyl (meth) acrylate, 1-methylallyl (meth) acrylate, 2-methylallyl (meth) acrylate, 1-butenyl (meth) acrylate, 2-butenyl (meth) acrylate, (meth) acrylic acid 3- Butenyl, 1,3-methyl-3-butenyl (meth) acrylate, 2-chloroallyl (meth) acrylate, 3-chloroallyl (meth) acrylate, o-allylphenyl (meth) acrylate, (meth) acrylic acid 2- (allyloxy) ethyl, allyl lactyl (meth) acrylate, citronellyl (meth) acrylate, geranyl (meth) acrylate, rosinyl (meth) acrylate, cinnamyl (meth) acrylate, vinyl (meth) acrylate, etc. Unsaturated group-containing (meth) acrylic acid esters;
Heterocycle-containing (meth) acrylic acid esters such as (meth) acrylic acid glycidyl, (meth) acrylic acid (3,4-epoxycyclohexyl) methyl, (meth) acrylic acid tetrahydrofurfuryl;
Amino groups such as N-methylaminoethyl (meth) acrylate, N-tributylaminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, and N, N-diethylaminoethyl (meth) acrylate Containing (meth) acrylic acid esters;
Alkoxysilyl such as 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropyltriisopropoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane Group-containing (meth) acrylic acid esters;
(Meth) acrylic acid derivatives such as (meth) acrylic acid methoxyethyl, ethylene oxide adducts of (meth) acrylic acid;
(Meth) acrylic acid perfluoroalkyl esters such as (meth) acrylic acid perfluoroethyl, (meth) acrylic acid perfluoropropyl, (meth) acrylic acid perfluorobutyl, (meth) acrylic acid perfluorooctyl;
Trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, 1,1,1-trishydroxymethylethane diacrylate, 1,1,1-trishydroxymethylethane triacrylate, 1,1, 1-trishydroxymethylpropane polyfunctional (meth) acrylic acid esters such as triacrylic acid;
Perfluoromethyl (meth) acrylate, trifluoromethyl methyl (meth) acrylate, 2-trifluoromethyl ethyl (meth) acrylate, diperfluoromethyl methyl (meth) acrylate, 2-par (meth) acrylate Fluoroethylethyl, 2-perfluoromethyl-2-perfluoroethylmethyl (meth) acrylate, triperfluoromethylmethyl (meth) acrylate, 2-perfluoroethyl-2-perfluorobutylethyl (meth) acrylate Fluorine-containing (meth) acrylic acid esters such as 2-perfluorohexylethyl (meth) acrylate, 2-perfluorodecylethyl (meth) acrylate, 2-perfluorohexadecylethyl (meth) acrylate;
Examples thereof include, but are not limited to, acrylic monomers. These may use only 1 type or may use multiple types together.

Other monomers such as vinyl monomers copolymerizable with acrylic monomers can also be used.
For example, aromatic vinyl systems such as styrene, α-methylstyrene, β-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 1-butylstyrene, chlorostyrene, styrenesulfonic acid and sodium salts thereof monomer;
Trialkyloxysilyl group-containing vinyl monomers such as vinyltrimethoxysilane and vinyltriethoxysilane;
silicon-containing vinyl monomers such as γ- (methacryloyloxypropyl) trimethoxysilane;
Nitrile group-containing vinyl monomers such as acrylonitrile and methacrylonitrile;
Amide group-containing vinyl monomers such as acrylamide and methacrylamide;
Vinyl esters such as vinyl acetate, vinyl propionate, vinyl pivalate, vinyl benzoate, vinyl cinnamate;
Fluorine-containing monomers such as perfluoroethylene, perfluoropropylene, vinylidene fluoride;
However, it is not particularly limited to these. These may use only 1 type or may use multiple types together.

The copolymer (a) used in the present invention is obtained by radical polymerization of iso-butyl methacrylate, a monomer having at least one of a carboxyl group or a hydroxyl group, and another copolymerizable monomer in an organic solvent. be able to.
It is important that the amount of iso-butyl methacrylate used is 8 to 20% by weight out of a total of 100% by weight of monomers used for polymerization. If iso-butyl methacrylate is less than 8% by weight, the cohesive strength of the pressure-sensitive adhesive layer cannot be expected to be improved so much that adhesiveness tends to be lowered. On the other hand, when the amount of iso-butyl methacrylate is more than 20% by weight, the glass transition temperature of the obtained copolymer becomes high and the impact resistance due to dropping tends to be lowered. Preferably, it is 9 to 16% by weight.

The monomer having a carboxyl group used for obtaining the copolymer (a) is 0.5 to 10% by weight in the total 100% by weight of the monomers to be polymerized from the viewpoint of adhesive strength and cohesive strength as a pressure-sensitive adhesive. Copolymerization is preferred.
When the monomer having a carboxyl group is less than 0.5% by weight, the cohesive force of the pressure-sensitive adhesive layer is lowered and the adhesiveness tends to be lowered. On the other hand, when the monomer having a carboxyl group is used in an amount of more than 10% by weight, the glass transition temperature of the resulting copolymer is increased, and the impact resistance due to dropping tends to be lowered. More preferably, it is 1 to 6% by weight.
The monomer having a hydroxyl group used for obtaining the copolymer (a) is mainly used when an isocyanate compound is used as a cross-linking agent, and 0.01% of the total 100% by weight of monomers used for polymerization. It is preferred to copolymerize ~ 5% by weight. If it is less than 0.01% by weight, it is difficult to obtain sufficient adhesive force, the cohesive force of the pressure-sensitive adhesive layer is lowered, and the adhesiveness tends to be lowered. On the other hand, if the monomer having a hydroxyl group is used in an amount of more than 5% by weight, impact resistance due to dropping tends to be lowered. More preferably, it is 0.05 to 2% by weight.
A monomer containing a carboxyl group or a monomer containing a hydroxyl group can be used alone or in combination.

The copolymer (a) used in the present invention is composed of 2-ethylhexyl acrylate and acrylic which can form a homopolymer having a glass transition temperature (Tg) of −50 ° C. or lower among the other copolymerizable monomers described above. Acrylic acid ester having an alkyl side chain such as n-butyl acid, octyl acrylate, nonyl acrylate, decyl acrylate, lauryl acrylate, stearyl acrylate, and the like in 60% to 91.5% in 100% by weight of copolymerizable monomer %, And may be used alone or in combination.
The copolymer (a) used in the present invention is an alkenyl group-containing compound or an α, β-insoluble compound capable of forming a homopolymer having a Tg in the range of −30 to 120 ° C. among other copolymerizable monomers described above. Saturated carboxylic acid esters can be used as appropriate.

It is important to copolymerize iso-butyl methacrylate and the various monomers described above so that a copolymer (a) having a glass transition temperature (Tg) of −70 to −40 ° C. can be formed.
When the Tg of the copolymer is less than -70 ° C, the cohesive force of the formed pressure-sensitive adhesive layer is lowered, and it tends to be difficult to obtain high adhesiveness against deformation of the fixing member.
On the other hand, when the glass transition temperature of the copolymer exceeds −40 ° C., impact resistance due to dropping tends to decrease. Preferably, it is −60 to −45 ° C.

As an organic solvent used when polymerizing the copolymer (a), ethyl acetate, n-butyl acetate, isobutyl acetate, toluene, acetone, hexane, methyl ethyl ketone and the like are used. These polymerization solvents may be used as a mixture of two or more.
Examples of the polymerization initiator used when polymerizing the copolymer (a) include benzoyl peroxide, di-t-butyl peroxide, cumene hydroperoxide, t-butyl peroxybenzoate, and t-butyl peroxy. Organic peroxide polymerization initiators such as neodecanoate and t-butylperoxy 2-ethylhexanoate; 2,2′-azobis (2-methylbutyronitrile), 2,2′-azobiscyclohexane Although radical polymerization initiators, such as azo polymerization initiators, such as carbonitrile, are mentioned, it is not specifically limited. Only one kind of these polymerization initiators may be used, or two or more kinds may be appropriately mixed and used. What is necessary is just to set the usage-amount of a polymerization initiator according to a composition, reaction conditions, etc. of the monomer with which it superposes | polymerizes, and it does not specifically limit.

Further, when the copolymer (a) is polymerized, a chain transfer agent can also be used.
Examples of chain transfer agents that can be used include alkyl mercaptans such as octyl mercaptan, nonyl mercaptan, decyl mercaptan, dodecyl mercaptan, thioglycolic acid esters such as octyl thioglycolate, nonyl thioglycolate, and 2-ethylhexyl thioglycolate. 2,4-diphenyl-4-methyl-1-pentene, 1-methyl-4-isopropylidene-1-cyclohexene, and the like. In particular, when thioglycolic acid esters, 2,4-diphenyl-4-methyl-1-pentene, and 1-methyl-4-isopropylidene-1-cyclohexene are used, the resulting copolymer has a low odor. preferable. In addition, when using a chain transfer agent, it is used in about 0.001-3 weight part with respect to a total of 100 weight part of the monomer to superpose | polymerize.
The polymerization reaction is usually performed at a temperature of 40 to 100 ° C. over 2 to 8 hours.

It is important that the weight average molecular weight of the copolymer (a) used in the present invention is 400,000 to 1,200,000, preferably 500,000 to 1,000,000. When the weight average molecular weight is less than 400,000, even if a crosslinking agent is added, the cohesive force of the pressure-sensitive adhesive layer is insufficient, and the adhesiveness tends to decrease. On the other hand, when the weight average molecular weight exceeds 1,200,000, the elasticity of the pressure-sensitive adhesive layer becomes high, and the impact resistance due to dropping tends to decrease.
In addition, the pressure-sensitive adhesive (b) in the present invention may be blended with a resin for pressure-sensitive adhesives having a composition or molecular weight other than the range specified in the present invention, as long as the purpose of the present invention is not impaired. Good.

The pressure-sensitive adhesive (b) used in the present invention contains the copolymer (a), which is a so-called main agent, and a crosslinking agent.
A crosslinking agent has a functional group which can react with at least one of the carboxyl group or hydroxyl group which the said copolymer (a) has. Examples of such a crosslinking agent include an isocyanate crosslinking agent, an epoxy crosslinking agent, a metal chelate crosslinking agent, an aziridine crosslinking agent, an amine crosslinking agent, a carbodiimide compound, an oxazoline compound, and a melamine compound. By using the crosslinking agent, the cohesive force of the pressure-sensitive adhesive layer can be further improved. Only one kind of these crosslinking agents may be used, or two or more kinds may be used in combination.

Here, examples of the isocyanate-based crosslinking agent include aromatic polyisocyanate, aliphatic polyisocyanate, araliphatic polyisocyanate, and alicyclic polyisocyanate.
Aromatic polyisocyanates include 1,3-phenylene diisocyanate, 4,4′-diphenyl diisocyanate, 1,4-phenylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6-triisocyanate. Range isocyanate, 4,4'-toluidine diisocyanate, 2,4,6-triisocyanate toluene, 1,3,5-triisocyanate benzene, dianisidine diisocyanate, 4,4'-diphenyl ether diisocyanate, 4,4 ', 4 " -Triphenylmethane triisocyanate etc. can be mentioned.
Aliphatic polyisocyanates include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), pentamethylene diisocyanate, 1,2-propylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, dodecamethylene diisocyanate. 2,4,4-trimethylhexamethylene diisocyanate and the like.
Examples of the araliphatic polyisocyanate include ω, ω′-diisocyanate-1,3-dimethylbenzene, ω, ω′-diisocyanate-1,4-dimethylbenzene, ω, ω′-diisocyanate-1,4-diethylbenzene, , 4-tetramethylxylylene diisocyanate, 1,3-tetramethylxylylene diisocyanate, and the like.
Examples of alicyclic polyisocyanates include 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate (IPDI), 1,3-cyclopentane diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, methyl- Examples include 2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 4,4′-methylene bis (cyclohexyl isocyanate), 1,4-bis (isocyanate methyl) cyclohexane and the like.

In addition, a trimethylolpropane adduct of the above polyisocyanate, a trimer having an isocyanurate ring, etc. can be used in combination. Polyphenylmethane polyisocyanate (PAPI), naphthylene diisocyanate, and these polyisocyanate modified products can be used. As the polyisocyanate-modified product, a carbodiimide group, a uretdione group, a uretoimine group, a burette group reacted with water, a group of isocyanurate groups, or a modified product having two or more of these groups can be used. A reaction product of a polyol and a diisocyanate can also be used as a polyisocyanate.
These polyisocyanate compounds include 4,4′-diphenylmethane diisocyanate, hexamethylene diisocyanate, 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate (isophorone diisocyanate), xylylene diisocyanate, 4,4′-methylenebis. From the viewpoint of weather resistance, it is particularly preferable to use a non-yellowing or hardly yellowing polyisocyanate compound such as (cyclohexyl isocyanate) (hydrogenated MDI).

Examples of epoxy crosslinking agents include bisphenol A-epichlorohydrin type epoxy resins, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerin diglycidyl ether, glycerin triglycidyl ether, 1,6-hexanediol. Diglycidyl ether, trimethylolpropane triglycidyl ether, diglycidylaniline, N, N, N ′, N′-tetraglycidyl-m-xylylenediamine, 1,3-bis (N, N′-diglycidylaminomethyl) And cyclohexane.

  Examples of metal chelate-based crosslinking agents include chelate compounds composed of acetylacetone and acetone esters of divalent or higher metals such as aluminum, copper, iron, tin, zinc, titanium, nickel, antimony, magnesium, vanadium, chromium, and zirconium. Is mentioned.

  Examples of the aziridine-based crosslinking agent include trimethylolpropane-tri-β-aziridinylpropionate, bisisophthaloyl-1- (2-methylaziridine), and the like.

  As the amine-based crosslinking agent, any polyamine having two or more primary amino groups can be used without particular limitation. A polyamine having two or more primary amino groups that are not directly bonded to the aromatic ring, that is, the primary amino group is directly bonded to an aliphatic functional group or an alicyclic functional group because of its excellent curing speed. Aliphatic polyamines are preferred. The aliphatic polyamine may contain an aromatic ring in its skeleton as long as the aromatic ring is not directly bonded to the primary amino group.

Aliphatic polyamines include 2,5-dimethyl-2,5-hexamethylenediamine, mensendiamine, 1,4-bis (2-amino-2-methylpropyl) piperazine, and propylene branched carbon at both ends of the molecule. Polypropylene glycol to which an amino group is bonded [a diamine having a propylene skeleton, such as “Jefamine D230” and “Jefamine D400” manufactured by Sun Techno Chemical Co., Ltd.], and a triamine having a propylene skeleton, such as “Jeffamine T403”. ], Ethylenediamine, propylenediamine, butylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, hexamethylenediamine, trimethylhexamethylenediamine, N-aminoethylpiperazine, 1,2-diaminopropane, iminobispropyl Amines such as amine, methyliminobispropylamine, H ₂ N (CH ₂ CH ₂ O) ₂ (CH ₂ ) ₂ NH ₂ [“Jefamine EDR148” (diamine with ethylene glycol skeleton) manufactured by Sun Techno Chemical Co.] Polyether skeleton diamine, 1,5-diamino-2-methylpentane ("MPMD" manufactured by DuPont Japan), metaxylylenediamine (MXDA), polyamidoamine (Sanwa Chemical) "X2000"), isophoronediamine, 1,3-bisaminomethylcyclohexane ("1,3BAC" manufactured by Mitsubishi Gas Chemical Company), 1-cyclohexylamino-3-aminopropane, 3-aminomethyl-3,3,5 -Trimethyl-cyclohexylamine, dimethyleneamine having a norbornane skeleton (“NBDA” manufactured by Mitsui Chemicals) and the like.
Among these, since the curing rate is particularly high, 1,3-bisaminomethylcyclohexane, dimethyleneamine having a norbornane skeleton, metaxylylenediamine, H ₂ N (CH ₂ CH ₂ O) ₂ (CH ₂ ) ₂ NH ₂ (ethylene glycol skeleton diamine), propylene skeleton diamine, propylene skeleton triamine, and polyamidoamine (trade name: X2000).
Ketimines, which are the reaction products of these polyamines and ketones, are also included in the amine compounds, and from the viewpoints of stability, reactivity adjustment and overcoatability, acetophenone or propiophenone and 1,3-bisaminomethylcyclohexane Obtained from acetophenone or propiophenone and dimethyleneamine (NBDA) having a norbornane skeleton; obtained from acetophenone or propiophenone and metaxylylenediamine; acetophenone or propiophenone; Those obtained from Jeffamine EDR148, Jeffamine D230 and Jeffamine D400, which are diamines having an ethylene glycol skeleton or propylene skeleton, or Jeffamine T403, which is a triamine having a propylene skeleton, etc. It is below.

As the carbodiimide compound, a compound having two or more carbodiimide groups (—N═C═N—) in the molecule is preferably used, and known polycarbodiimides can be used.
As the carbodiimide compound, high molecular weight polycarbodiimide produced by decarboxylation condensation reaction of diisocyanate in the presence of a carbodiimidization catalyst can also be used.
Examples of such compounds include those obtained by decarboxylation condensation reaction of the following diisocyanates. As the diisocyanate, 4,4′-diphenylmethane diisocyanate, 3,3′-dimethoxy-4,4′-diphenylmethane diisocyanate, 3,3′-dimethyl-4,4′-diphenylmethane diisocyanate, 4,4′-diphenyl ether diisocyanate, 3,3′-dimethyl-4,4′-diphenyl ether diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1-methoxyphenyl-2,4-diisocyanate, isophorone diisocyanate, 4,4′- One kind of dicyclohexylmethane diisocyanate, tetramethylxylylene diisocyanate or a mixture thereof can be used. As the carbodiimidization catalyst, 1-phenyl-2-phospholene-1-oxide, 3-methyl-2-phospholene-1-oxide, 1-ethyl-3-methyl-2-phospholene-1-oxide, 1-ethyl- Phosphorene oxides such as 2-phospholene-1-oxide or their 3-phospholene isomers can be used.

  As the oxazoline compound, a compound having two or more oxazoline groups in the molecule is preferably used. Specifically, 2'-methylenebis (2-oxazoline), 2,2'-ethylenebis (2-oxazoline), 2 2,2'-ethylenebis (4-methyl-2-oxazoline), 2,2'-propylenebis (2-oxazoline), 2,2'-tetramethylenebis (2-oxazoline), 2,2'-hexamethylene Bis (2-oxazoline), 2,2'-octamethylenebis (2-oxazoline), 2,2'-p-phenylenebis (2-oxazoline), 2,2'-p-phenylenebis (4,4 ' -Dimethyl-2-oxazoline), 2,2'-p-phenylenebis (4-methyl-2-oxazoline), 2,2'-p-phenylenebis (4-phenyl- -Oxazoline), 2,2'-m-phenylenebis (2-oxazoline), 2,2'-m-phenylenebis (4-methyl-2-oxazoline), 2,2'-m-phenylenebis (4 4'-dimethyl-2-oxazoline), 2,2'-m-phenylenebis (4-phenylenebis-2-oxazoline), 2,2'-o-phenylenebis (2-oxazoline), 2,2'- o-phenylenebis (4-methyl-2-oxazoline), 2,2'-bis (2-oxazoline), 2,2'-bis (4-methyl-2-oxazoline), 2,2'-bis (4 -Ethyl-2-oxazoline), 2,2'-bis (4-phenyl-2-oxazoline) and the like. Alternatively, it may be a copolymer of vinyl compounds such as 2-isopropenyl-2-oxazoline and 2-isopropenyl-4,4-dimethyl-2-oxazoline, and other monomers copolymerizable therewith.

  The melamine compound is a compound having a triazine ring in the molecule, and examples thereof include melamine, benzoguanamine, cyclohexanecarboguanamine, methylguanamine, vinylguanamine, hexamethoxymethylmelamine, tetramethoxymethylbenzoguanamine and the like. Further, these low condensation products, alkyl etherified formaldehyde resins, and aminoplast resins may be used.

The amount of the crosslinking agent used may be determined in consideration of the type of the copolymer (a), adhesive physical properties, etc., and is not particularly limited, but by adjusting the amount of the crosslinking agent, The crosslinking density (gel fraction) of the pressure-sensitive adhesive layer can be adjusted to an appropriate value. In other words, the use amount of the crosslinking agent preferably contains a crosslinking agent as appropriate so that the gel fraction of the pressure-sensitive adhesive layer is in the range of 30 to 80%, and the gel fraction is in the range of 40 to 60%. More preferably. When the gel fraction of the pressure-sensitive adhesive layer is less than 30%, the cohesive force of the pressure-sensitive adhesive layer is insufficient, and the adhesiveness tends to decrease. On the other hand, when the gel fraction of the pressure-sensitive adhesive layer exceeds 80%, the elasticity of the pressure-sensitive adhesive layer increases, and the impact resistance due to dropping tends to decrease.
In addition, the addition method which adds a crosslinking agent to an acrylic copolymer (a) is not specifically limited.
Moreover, in the pressure-sensitive adhesive (b) in the present invention, as long as the purpose of the present invention is not impaired, a tackifier resin, a silane coupling agent, a weathering stabilizer, which is blended with a conventional acrylic pressure-sensitive adhesive, if desired, Various additive components such as a plasticizer, a softening material, a dye, a pigment, and an inorganic filler can be contained.

  Examples of the tackifier include terpene resin, aliphatic petroleum resin, aromatic petroleum resin, coumarone-indene resin, phenol resin, terpene-phenol resin, rosin derivative (rosin, polymerized rosin, hydrogenated rosin, and glycerin thereof. All existing ones such as esters with pentaerythritol, resin acid dimers, etc.) can be used. As the plasticizer, known materials such as phthalates and phosphates can be used.

Next, the pressure-sensitive adhesive sheet of the present invention will be described.
The pressure-sensitive adhesive sheet of the present invention is a double-sided pressure-sensitive adhesive sheet obtained by laminating a pressure-sensitive adhesive layer (A) on both surfaces of a support. That is, it can be obtained by, for example, applying and drying the adhesive (b) solution on both sides of the support, and the thickness of the support after drying is 5 μm to 200 μm, preferably 40 μm to 100 μm in thickness. What a laminated | stacked agent layer is preferable. When the thickness of the pressure-sensitive adhesive layer is less than 5 μm per side, peeling may easily occur due to unevenness or impact on the surface of the adherend. Conversely, when the thickness of the pressure-sensitive adhesive layer exceeds 200 μm per side, Despite the fact that the adhesion and adhesion to the film no longer improve, the cost increases.
In addition, a support body said here means polyester-type films, such as a nonwoven fabric or a polyethylene terephthalate film. The thickness of the support can be 4 to 200 [mu] m, which is generally used conventionally, but is preferably 10 to 100 [mu] m.
Non-woven fabrics made of natural fibers such as Manila hemp, pulp, rayon, acetate fibers, polyester fibers, polyvinyl alcohol fibers, polyamide fibers, polyolefin fibers, semi-synthetic fibers or synthetic fiber fibrous materials, etc. Of cloth. In order to improve the strength of the nonwoven fabric at the stage of producing the nonwoven fabric, it is preferable to use a strength improver. Examples of the strength improver include viscose, and examples of the cationic polymer include polyamide, amine, and epichlorohydrin resin. The strength improver can be added at the paper making stage of the nonwoven fabric, or can be applied or impregnated after paper making.

In the pressure-sensitive adhesive sheet of the present invention, a peelable sheet can be laminated on the pressure-sensitive adhesive layer on at least one surface thereof.
As the release sheet, glassine paper, kraft paper, clay coated paper, paper laminated with a film such as polyethylene, paper coated with a resin such as polyvinyl alcohol or acrylate copolymer, synthetic resin film such as polyester or polypropylene And the like obtained by applying a fluorine resin, a silicone resin or the like as a release agent. The peelable sheet is also called a separator or a release paper.
When laminating a peelable sheet on both pressure-sensitive adhesive layers of the pressure-sensitive adhesive sheet of the present invention, in order to improve workability, the peelability of each peelable sheet laminated on both surfaces is different. It is preferable to select a sheet. For example, the peelability of the peelable sheet on the side to be attached at the beginning of the double-sided pressure-sensitive adhesive sheet is such that the workability is improved by selecting a peelable sheet that is lighter than the peelability of the peelable sheet on the side to be stuck next. improves.

The double-sided PSA sheet of the present invention can be obtained by various methods.
For example, by a method of directly applying and drying the pressure-sensitive adhesive solution to the support, or by applying a pressure-sensitive adhesive solution to the peelable sheet, drying, and then laminating the support on the formed pressure-sensitive adhesive layer, a so-called transfer method, First, an adhesive layer can be laminated on one surface of the support.
Next, also on the other surface of the support, a pressure-sensitive adhesive layer is formed by directly applying and drying the pressure-sensitive adhesive solution or using a transfer method, and a double-sided pressure-sensitive adhesive sheet is obtained.
In addition, it is preferable to employ a transfer method because of excellent productivity.
The application device used when applying the adhesive to the support or the release sheet is a commonly used application device and is not particularly limited. For example, a roll knife coater, a die coater, a roll coater, a bar Examples include coaters, gravure roll coaters, reverse roll coaters, dipping, blade coaters and the like.
The drying conditions may be any conditions as long as the solvent of the pressure-sensitive adhesive solution is dried and removed during drying, and the functional group of the copolymer (a) reacts with the crosslinking agent to form a crosslinked structure. . For example, 60 to 120 ° C. and about 1 to 5 minutes are preferable, but not limited thereto. After drying, aging can be performed with the pressure-sensitive adhesive layer (A) sandwiched between the support and the peelable sheet, and the crosslinking reaction can further proceed.

  Moreover, when using a nonwoven fabric as a support body, in order to impregnate an adhesive layer to the inside of a nonwoven fabric, after laminating | stacking an adhesive layer, you may use the method of heat laminating at the temperature of 50 degreeC or more. .

  Moreover, the double-sided pressure-sensitive adhesive sheet of the present invention can be provided in a roll shape, can be provided in a single-wafer state, or can be further processed into various shapes.

Next, the member (D) of the present invention and the manufacturing method thereof will be described with reference to the drawings.
The member (D) is provided at a position where a frame member (B) having an opening and a window member (C) for covering the opening of the frame member surround the opening of the frame member (B). It is laminated through the pressure-sensitive adhesive sheet of the present invention.

(1) of FIG. 1 is a window member (C) for covering the opening of the frame member (B). (2) of FIG. 1 represents the double-sided adhesive sheet processed so that the opening part of a frame member (B) may be surrounded. The processing of the double-sided pressure-sensitive adhesive sheet is usually performed in a state where a peelable sheet is laminated on both surfaces, and can be processed manually or by a punching machine. The blade to be processed is a method of completely penetrating the peelable sheet laminated on the surface opposite to the surface into which the blade is inserted or deeply penetrating the adhesive layer to such an extent that the peelable sheet is not cut (also called half cut). May be used.
(3) in FIG. 1 peels and removes the peelable sheet on one side of the double-sided pressure-sensitive adhesive sheet in (2) in FIG. 1, and attaches it to the peripheral part of the window member (C) in (1) in FIG. The window member with an adhesive layer obtained by making it represent is represented.
And as shown to (5) of FIG. 1, another peelable sheet is removed from the double-sided adhesive sheet on the window member with an adhesive layer obtained by (3) of FIG. 1, and (4) of FIG. The frame member (B) and the window member (C) are laminated via the pressure-sensitive adhesive sheet of the present invention by pasting so as to cover the opening of the frame member (B).

  Specific examples of the frame member (B) include a display panel portion of a mobile phone, a portable personal computer, a portable information terminal device (PDA), and the like. The material constituting the frame member (B) is not particularly limited, such as synthetic resin and metals, but these can be processed into a desired shape by hot pressing or the like. The frame member (B) may be painted or coated with a commonly used paint or coating agent for the purpose of design or damage prevention.

  Moreover, the magnitude | size and shape of the opening part of a frame member (B) are not specifically limited, There may be 1 or 2 or more. The opening is mainly for storing the liquid crystal display member, and the window member (C) is provided so as to protect the liquid crystal display member.

The material constituting the window member (C) is not particularly limited, such as glass, synthetic resin such as acrylic resin, polycarbonate resin, etc., but often for the purpose of protecting liquid crystal display panels, etc. A transparent material is selected. In addition, after the window member (C) is laminated on the frame member (B), it is joined from the exterior of the window member (C) from the viewpoint of design such that the adhesive sheet existing at the lamination interface is not visible. The interior of the part may be decorated with aluminum vapor deposition or printing.
Further, the window member (C) may be painted or coated with a commonly used paint or coating agent.

  Next, although an example of the present invention is shown and explained in detail, the present invention is not limited by these. In the examples, “part” means “part by weight” and “%” means “% by weight”.

Example 1
In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping device, and a nitrogen introduction tube, 77.9 parts of 2-ethylhexyl acrylate, 10 parts of n-butyl acrylate, 10 parts of iso-butyl methacrylate, 2 parts of acrylic acid , 0.1 part of 2-hydroxyethyl acrylate, 47 parts of ethyl acetate and 0.11 part of 2,2′-azobis (2-methylbutyronitrile) were charged, and the air in the reaction vessel was replaced with nitrogen gas. The reaction solution was reacted at reflux temperature for 8 hours in a nitrogen atmosphere with stirring. After completion of the reaction, the solution was diluted with ethyl acetate to obtain an acrylic copolymer solution having a nonvolatile content concentration of about 40% and a weight average molecular weight Mw of about 650,000. To 100 parts by weight of the obtained acrylic copolymer solution, 0.8 part of an isocyanate crosslinking agent (“Coronate L” manufactured by Nippon Polyurethane Industry Co., Ltd., non-volatile content: 75%) was added and stirred uniformly to obtain an adhesive. A solution was obtained.
The obtained pressure-sensitive adhesive solution was applied onto a commercially available separator so that the dry coating thickness was 70 μm, dried at 100 ° C. for 2 minutes, and this pressure-sensitive adhesive layer surface and a commercially available nonwoven fabric weighing 14 g / m ² Were pasted together. Furthermore, the other surface of the nonwoven fabric was similarly bonded with a separator provided with a pressure-sensitive adhesive layer to produce a double-sided pressure-sensitive adhesive sheet in which the pressure-sensitive adhesive layer was laminated on both surfaces of the nonwoven fabric.

(Example 2)
In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping device, and a nitrogen introduction tube, 76.9 parts of 2-ethylhexyl acrylate, 10 parts of n-butyl acrylate, 10 parts of iso-butyl methacrylate, 3 parts of acrylic acid , 0.1 part of 2-hydroxyethyl acrylate, 47 parts of ethyl acetate and 0.11 part of 2,2′-azobis (2-methylbutyronitrile) were charged, and the air in the reaction vessel was replaced with nitrogen gas. The reaction solution was reacted at reflux temperature for 8 hours in a nitrogen atmosphere with stirring. After completion of the reaction, the reaction mixture was diluted with ethyl acetate to obtain an acrylic copolymer solution having a nonvolatile content concentration of about 40% and a weight average molecular weight Mw of about 670,000. To 100 parts by weight of the obtained acrylic copolymer solution, 0.8 part of an isocyanate crosslinking agent (“Coronate L” manufactured by Nippon Polyurethane Industry Co., Ltd., non-volatile content: 75%) was added and stirred uniformly to obtain an adhesive. A solution was obtained.
A double-sided PSA sheet was produced in the same manner as Example 1 using the obtained PSA solution.

(Example 3)
In a reaction vessel equipped with a stirrer, thermometer, reflux condenser, dropping device, and nitrogen introduction tube, 75.9 parts 2-ethylhexyl acrylate, 8 parts n-butyl acrylate, 15 parts iso-butyl methacrylate, 1 part acrylic acid , 0.1 part of 2-hydroxyethyl acrylate, 47 parts of ethyl acetate and 0.11 part of 2,2′-azobis (2-methylbutyronitrile) were charged, and the air in the reaction vessel was replaced with nitrogen gas. The reaction solution was reacted at reflux temperature for 8 hours in a nitrogen atmosphere with stirring. After completion of the reaction, the solution was diluted with ethyl acetate to obtain an acrylic copolymer solution having a nonvolatile content concentration of about 40% and a weight average molecular weight Mw of about 630,000. To 100 parts by weight of the obtained acrylic copolymer solution, 0.8 part of an isocyanate crosslinking agent (“Coronate L” manufactured by Nippon Polyurethane Industry Co., Ltd., non-volatile content: 75%) was added and stirred uniformly to obtain an adhesive. A solution was obtained.
A double-sided PSA sheet was produced in the same manner as Example 1 using the obtained PSA solution.

(Comparative Example 1)
In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping device, and a nitrogen introduction tube, 56.9 parts of 2-ethylhexyl acrylate, 30 parts of n-butyl acrylate, 10 parts of methyl acrylate, 3 parts of acrylic acid, 2 -0.1 parts of hydroxyethyl acrylate, 72 parts of ethyl acetate, 0.11 part of 2,2'-azobis (2-methylbutyronitrile) were charged, and the air in the reaction vessel was replaced with nitrogen gas, followed by stirring. The reaction solution was reacted at reflux temperature for 8 hours in a nitrogen atmosphere. After completion of the reaction, the solution was diluted with ethyl acetate to obtain an acrylic copolymer solution having a nonvolatile content concentration of about 40% and a weight average molecular weight Mw of about 660,000. To 100 parts by weight of the obtained acrylic copolymer solution, 0.8 part of an isocyanate crosslinking agent (“Coronate L” manufactured by Nippon Polyurethane Industry Co., Ltd., non-volatile content: 75%) was added and stirred uniformly to obtain an adhesive. A solution was obtained.
A double-sided PSA sheet was produced in the same manner as Example 1 using the obtained PSA solution.

(Comparative Example 2)
In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping device, and a nitrogen introduction tube, 67.9 parts of 2-ethylhexyl acrylate, 30 parts of n-butyl acrylate, 2 parts of acrylic acid, 2-hydroxyethyl acrylate 0 .1 part, 59 parts of ethyl acetate and 0.11 part of 2,2′-azobis (2-methylbutyronitrile) were charged, and the air in the reaction vessel was replaced with nitrogen gas. The reaction solution was reacted at reflux temperature for 8 hours. After completion of the reaction, the solution was diluted with ethyl acetate to obtain an acrylic copolymer solution having a nonvolatile content concentration of about 40% and a weight average molecular weight Mw of about 640,000. To 100 parts by weight of the obtained acrylic copolymer solution, 0.8 part of an isocyanate crosslinking agent (“Coronate L” manufactured by Nippon Polyurethane Industry Co., Ltd., non-volatile content: 75%) was added and stirred uniformly to obtain an adhesive. A solution was obtained.
A double-sided PSA sheet was produced in the same manner as Example 1 using the obtained PSA solution.

(Comparative Example 3)
In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping device, and a nitrogen introduction tube, 93.9 parts of n-butyl acrylate, 6 parts of acrylic acid, 0.1 part of 2-hydroxyethyl acrylate, 100 parts of ethyl acetate, After charging 0.11 part of 2,2′-azobis (2-methylbutyronitrile) and replacing the air in the reaction vessel with nitrogen gas, the reaction solution was refluxed in a nitrogen atmosphere with stirring. For 8 hours. After completion of the reaction, the solution was diluted with ethyl acetate to obtain an acrylic copolymer solution having a nonvolatile content concentration of about 40% and a weight average molecular weight Mw of about 690,000. To 100 parts by weight of the obtained acrylic copolymer solution, 0.8 part of an isocyanate crosslinking agent (“Coronate L” manufactured by Nippon Polyurethane Industry Co., Ltd., non-volatile content: 75%) was added and stirred uniformly to obtain an adhesive. A solution was obtained.
A double-sided PSA sheet was produced in the same manner as Example 1 using the obtained PSA solution.

(Comparative Example 4)
In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping device, and a nitrogen introducing tube, 80.4 parts of 2-ethylhexyl acrylate, 10 parts of n-butyl acrylate, 8.5 parts of methyl methacrylate, 1 part of acrylic acid , 0.1 part of 2-hydroxyethyl acrylate, 43 parts of ethyl acetate and 0.11 part of 2,2′-azobis (2-methylbutyronitrile) were charged, and the air in the reaction vessel was replaced with nitrogen gas. The reaction solution was reacted at reflux temperature for 8 hours in a nitrogen atmosphere with stirring. After completion of the reaction, the reaction mixture was diluted with ethyl acetate to obtain an acrylic copolymer solution having a nonvolatile content concentration of about 40% and a weight average molecular weight Mw of about 670,000. To 100 parts by weight of the obtained acrylic copolymer solution, 0.8 part of an isocyanate crosslinking agent (“Coronate L” manufactured by Nippon Polyurethane Industry Co., Ltd., non-volatile content: 75%) was added and stirred uniformly to obtain an adhesive. A solution was obtained.
A double-sided PSA sheet was produced in the same manner as Example 1 using the obtained PSA solution.

(Comparative Example 5)
In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping device, and a nitrogen introduction tube, 60.9 parts of 2-ethylhexyl acrylate, 18 parts of n-butyl acrylate, 20 parts of normal-butyl methacrylate, 1 part of acrylic acid , 0.1 part of 2-hydroxyethyl acrylate, 67 parts of ethyl acetate and 0.11 part of 2,2′-azobis (2-methylbutyronitrile) were charged, and the air in the reaction vessel was replaced with nitrogen gas. The reaction solution was reacted at reflux temperature for 8 hours in a nitrogen atmosphere with stirring. After completion of the reaction, the reaction mixture was diluted with ethyl acetate to obtain an acrylic copolymer solution having a nonvolatile content concentration of about 40% and a weight average molecular weight Mw of about 680,000. To 100 parts by weight of the obtained acrylic copolymer solution, 0.8 part of an isocyanate crosslinking agent (“Coronate L” manufactured by Nippon Polyurethane Industry Co., Ltd., non-volatile content: 75%) was added and stirred uniformly to obtain an adhesive. A solution was obtained.
A double-sided PSA sheet was produced in the same manner as Example 1 using the obtained PSA solution.

(Comparative Example 6)
In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping device, and a nitrogen introduction tube, 76.9 parts of 2-ethylhexyl acrylate, 10 parts of n-butyl acrylate, 10 parts of iso-butyl methacrylate, 3 parts of acrylic acid , 0.1 part of 2-hydroxyethyl acrylate, 100 parts of toluene, 0.11 part of 2,2′-azobis (2-methylbutyronitrile) were charged, and the air in the reaction vessel was replaced with nitrogen gas. The reaction solution was reacted at reflux temperature for 8 hours under stirring in a nitrogen atmosphere. After completion of the reaction, the solution was diluted with ethyl acetate to obtain an acrylic copolymer solution having a nonvolatile content concentration of about 40% and a weight average molecular weight Mw of about 180,000. To 100 parts by weight of the obtained acrylic copolymer solution, 1.5 parts of an isocyanate crosslinking agent (“Coronate L” manufactured by Nippon Polyurethane Industry Co., Ltd., non-volatile content: 75%) was added and stirred uniformly to obtain an adhesive. A solution was obtained.
A double-sided PSA sheet was produced in the same manner as Example 1 using the obtained PSA solution.

(Comparative Example 7)
In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping device, and a nitrogen introduction tube, 76.9 parts of 2-ethylhexyl acrylate, 10 parts of n-butyl acrylate, 10 parts of iso-butyl methacrylate, 3 parts of acrylic acid , 0.1 part of 2-hydroxyethyl acrylate, 47 parts of acetone, 0.11 part of 2,2′-azobis (2-methylbutyronitrile) were charged, and the air in the reaction vessel was replaced with nitrogen gas. The reaction solution was reacted at reflux temperature for 8 hours under stirring in a nitrogen atmosphere. After completion of the reaction, the solution was diluted with ethyl acetate to obtain an acrylic copolymer solution having a nonvolatile content concentration of about 40% and a weight average molecular weight Mw of about 1.45 million. To 100 parts by weight of the obtained acrylic copolymer solution, 0.4 part of an isocyanate crosslinking agent (“Coronate L” manufactured by Nippon Polyurethane Industry Co., Ltd., non-volatile content: 75%) was added and stirred uniformly. A solution was obtained.
A double-sided PSA sheet was produced in the same manner as Example 1 using the obtained PSA solution.

(Comparative Example 8)
In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping device, and a nitrogen introduction tube, 68.9 parts 2-ethylhexyl acrylate, 30 parts iso-butyl methacrylate, 1 part acrylic acid, 2-hydroxyethyl acrylate 0 .1 part, 43 parts of ethyl acetate and 0.11 part of 2,2′-azobis (2-methylbutyronitrile) were charged, and the air in the reaction vessel was replaced with nitrogen gas. The reaction solution was reacted at reflux temperature for 8 hours. After completion of the reaction, the solution was diluted with ethyl acetate to obtain an acrylic copolymer solution having a nonvolatile content concentration of about 40% and a weight average molecular weight Mw of about 610,000. To 100 parts by weight of the obtained acrylic copolymer solution, 0.8 part of an isocyanate crosslinking agent (“Coronate L” manufactured by Nippon Polyurethane Industry Co., Ltd., non-volatile content: 75%) was added and stirred uniformly to obtain an adhesive. A solution was obtained.
A double-sided PSA sheet was produced in the same manner as Example 1 using the obtained PSA solution.

The types of copolymerizable monomers constituting the copolymer (a) in Table 1 are indicated by the following abbreviations.
BA: normal-butyl acrylate (molecular weight = 128, homopolymer Tg = −54 ° C.)
2EHA: 2-ethylhexyl acrylate (molecular weight = 184, homopolymer Tg = −85 ° C.)
iBMA: iso-butyl methacrylate (molecular weight = 142, homopolymer Tg = 67 ° C.) nBMA: normal-butyl methacrylate (molecular weight = 142, homopolymer Tg = 20 ° C.)
MA: methyl acrylate (molecular weight = 86, homopolymer Tg = 8 ° C.)
MMA: Methyl methacrylate (molecular weight = 100, homopolymer Tg = 105 ° C.)
AA: acrylic acid (molecular weight = 72, homopolymer Tg = 106 ° C.)
HEA: 2-hydroxyethyl acrylate (molecular weight = 116, Tg of homopolymer = −15 ° C.)

(Weight average molecular weight)
It is a weight average molecular weight in terms of polystyrene determined by GPC measurement, and the measurement conditions are as follows.
Equipment: HCL8820GPC manufactured by Tosoh Corporation
Column: Three TSKgel GMH _XL manufactured by Tosoh Corporation are connected and used.
Solvent: Tetrahydrofuran Flow rate: 0.5 ml / min
Temperature: 40 ° C
Sample concentration: 0.2 wt%
Sample injection volume: 100 μl

[Glass transition temperature (Tg)]
The Tg of the acrylic copolymer in the present invention is theoretically derived from the following formula [I].
Tg = [M1 / (M1 + M2 +... + Mn) × Tg1] + [M2 / (M1 + M2 +... + Mn) × Tg2] +... + [Mn / (M1 + M2 +... + Mn) × Tgn ] [I]
Where M1 = (weight% of monomer 1) / (molecular weight of monomer 1), Tg1: glass transition temperature (° C.) of homopolymer of monomer 1;
M2 = (% by weight of monomer 2) / (molecular weight of monomer 2), Tg2: glass transition temperature of homopolymer of monomer 2 (° C.),
Mn = (% by weight of monomer n) / (molecular weight of monomer n), Tgn: glass transition temperature (° C.) of homopolymer of monomer n.
(Here, the total monomer used for copolymerization is 100% by weight.)

[Measurement of physical properties of adhesive sheet]
About the double-sided adhesive sheet obtained by the Example and the comparative example, after making it pass in 23 degreeC-50% RH atmosphere for 7 days and aging an adhesive layer, the test shown below was done. The results are shown in Table 1. In addition, in the adhesive strength, holding power, and ball tack test, the separator on one side of the obtained double-sided pressure-sensitive adhesive sheet was peeled off, and a polyester film (trade name “Toyobo Ester”, thickness 25 μm, manufactured by Toyobo Co., Ltd.) was bonded. A sample was used as a measurement sample.

〔Adhesive force〕
This was performed according to JIS Z 0237. A test piece with a width of 25 mm was cut out from the measurement sample, the separator was peeled off, affixed to a stainless steel plate in an atmosphere at 23 ° C.-50%, left in the same environment for 20 minutes, and then in the same environment, 300 mm by a tensile tester. The peel strength (N / inch) when peeled at an angle of 180 ° at a tensile rate of / min was measured.

[Retention force]
Cut out a 25 mm wide test piece from the sample for measurement, peel off the separator, and apply it to a stainless steel plate (sticking area 25 mm x 25 mm). The deviation of the sticking position was measured (mm). In the case of falling within 1 hour, the time until dropping was determined.

[Ball tack]
This was performed according to JIS Z 0237. The inclination angle of the pressure-sensitive adhesive sheet was 30 °, and the measurement was performed in an atmosphere of 23 ° C.-50%.

[Extrusion strength]
The adhesive strength when the window member was actually fixed to the frame member was determined by the following method.
The double-sided pressure-sensitive adhesive sheet of 40 × 54 mm was punched so that an opening of 36 × 50 mm was formed, and a sample with a width of 2 mm was prepared (the area of the sample was 360 mm ² ). One of the separators of this sample is peeled off, and the sample is attached so that the positions from the ends of the four sides of the 40 × 54 × 3 mm thick acrylic plate to about 2 mm are covered, and the window member with the adhesive sheet is attached. Obtained.
Next, the separator is peeled off from the adhered sample, and the center of the window member with the adhesive sheet coincides with the center of the hole of the polycarbonate plate on the polycarbonate plate of 50 × 60 × thickness 2 mm having a hole with a diameter of 15 mm in the center. Then, the sample was pressed once and reciprocated with a 2 kg roller to obtain a sample for measuring the extrusion strength.
Maximum strength at which the acrylic plate peels off after standing for 30 minutes in a 23 ° C.-50% RH atmosphere, passing a stainless steel rod with a 5 mm tip diameter through the hole in the polycarbonate plate and extruding the acrylic plate at a speed of 10 mm / min. Asked.

[Drop test]
A sample for drop test was prepared by fixing a stainless steel plate so that the total weight was 210 g on the polycarbonate plate of the sample for measuring extrusion strength prepared in the measurement of [extrusion strength].
This test sample was allowed to stand for 30 minutes at 10 ° C. or 23 ° C.-50% RH atmosphere, and then 60 times on the concrete surface with the acrylic plate facing down from a height of 1.5 m in the same atmosphere. It was allowed to naturally drop continuously and evaluated for impact resistance.
The evaluation criteria are shown below.
O ... No dropout even when dropped 60 times from 1.5 m in a 10 ° C atmosphere and 23 ° C-50% atmosphere.
Δ: No dropout even when dropped 60 times from 1.5 m in a 23 ° C-50% atmosphere, but there was a dropout in a 10 ° C atmosphere.
X: Both dropped out in a drop within 60 degrees from 1.5 m in a 10 ° C. atmosphere and a 23 ° C.-50% atmosphere.

From Table 1, it can be seen that those using the pressure-sensitive adhesive (b) specified by the present invention as in Examples have good drop-off tests, and good extrusion strength can be obtained with respect to extrusion strength.
Among the comparative examples, those having a good drop-off test had a lower extrusion strength than the examples, and a sufficient strength could not be obtained.

It is process drawing which shows the process of fixing the frame member which has an opening part, and the window member for covering an opening part using the adhesive sheet of this invention.

Explanation of symbols

A: Window member with adhesive layer.
B: A frame member having an opening.
C: Window member for covering the opening.
D: A member in which a frame member and a window member are laminated via an adhesive sheet.
E: An adhesive sheet processed so as to surround the opening of the frame member.

Claims (3)

A pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer (A) on both sides of a nonwoven fabric or a polyester film,
The pressure-sensitive adhesive layer (A) is formed by copolymerizing 8 to 20% by weight of iso-butyl methacrylate and another copolymerizable monomer in 100% by weight of the total amount of monomers, and has at least one of a carboxyl group or a hydroxyl group. The copolymer (a) having a weight average molecular weight of 400,000 to 1,200,000 and a glass transition temperature of −70 ° C. to −40 ° C. has a functional group capable of reacting with at least one of a carboxyl group or a hydroxyl group. A pressure-sensitive adhesive sheet formed from a pressure-sensitive adhesive (b) containing a crosslinking agent. The pressure-sensitive adhesive according to claim 1, wherein a frame member (B) having an opening and a window member (C) for covering the opening of the frame member are provided at positions surrounding the opening of the frame member (B). A member (D) formed by stacking sheets. It is a manufacturing method of the member (D) of Claim 2, Comprising: The window member with an adhesive layer by which the one surface of the adhesive sheet of Claim 1 is stuck by the peripheral part of a window member (C), The method for producing a member (D), wherein the member (D) is pasted so as to cover the opening of the frame member (B) having the opening.

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