JP2017019955A - Double sided adhesive tape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a double sided adhesive tape capable of preferably being used during a manufacturing process or the like because one side of a substrate is weak adhesive having re-detachability and another is strong adhesive, hardly adhering an adhesive to a member or a processing blade or the like during shear processing, die stamping processing or the like and excellent in heat resistance.SOLUTION: There is solved by a double sided adhesive tape having adhesive force of an adhesive layer (A) which is stronger than that of the adhesive layer (B), gel fraction of the adhesive layer (A) of 30 to 60 wt.% and gel fraction of the adhesive layer (B) of 70 wt.% or more.SELECTED DRAWING: None

Description

  The present invention relates to a double-sided pressure-sensitive adhesive tape. In particular, the present invention relates to a double-sided pressure-sensitive adhesive tape that can be preferably used for manufacturing processes.

2. Description of the Related Art Conventionally, double-sided pressure-sensitive adhesive tapes are excellent in bonding workability and processing workability, and thus are used for fixing building materials, fixing automobile parts, fixing electronic equipment parts, and the like. Also, component fixing and temporary fixing in various industrial fields such as semiconductor manufacturing process, optical disk manufacturing process, primary battery and secondary battery manufacturing process, manufacturing process of mobile devices such as smartphones and tablets, etc. Many double-sided adhesive tapes are used.
In recent years, due to the downsizing of mobile devices and the like, double-sided adhesive tapes are often used for temporary fixing during processing in the manufacturing process of precision members. Therefore, there is a need for a double-sided pressure-sensitive adhesive tape having a different adhesive strength on both sides, in which one of the substrates is weakly adhesive having removability and the other is strongly adhesive.

  Therefore, Patent Document 1 and Patent Document 2 disclose double-sided pressure-sensitive adhesive tapes having different performance on both sides. Patent Document 3 discloses a double-sided tape excellent in workability. However, when the conventional double-sided adhesive tape is used in the manufacturing process of the member as described above, the adhesive constituting the double-sided tape protrudes and adheres to the member when the shearing or punching process is performed together with the member. (Hereinafter sometimes referred to as “extrusion”), the member itself can no longer be used, the stay is lowered, and the adhesive is attached to the processing blade, so the frequency of cleaning the processing blade increases. There have been problems such as a decrease in production efficiency and, when processing under high temperature conditions, the pressure-sensitive adhesive softens, resulting in a worsening of the protruding property. An excellent double-sided pressure-sensitive adhesive tape for use in a production process in which one of the substrates is a weak adhesive having removability and the other is a strong adhesive satisfying performance required in recent years has not been found.

JP 2008-088271 A JP-A-5-171118 JP 2014-221864 A

  In the present invention, one of the substrates is a weak adhesive having removability and the other is a strong adhesive, so that it can be preferably used during the manufacturing process, and also in the case of shearing or punching. An object of the present invention is to provide a double-sided pressure-sensitive adhesive tape in which the pressure-sensitive adhesive hardly adheres to a member, a processing blade or the like and has excellent heat resistance.

  As a result of intensive studies to solve the above problems, the present inventors have found that the adhesive strength of the pressure-sensitive adhesive layer (A) is higher than that of the pressure-sensitive adhesive layer (B), and the pressure-sensitive adhesive layer ( It discovered that the said subject could be solved because the gel fraction of A) and an adhesive layer (B) each has a specific range, and came to this invention.

  That is, this invention is equipped with an adhesive layer (A), a base material, and an adhesive layer (B), and the adhesive force of the said adhesive layer (A) is higher than the adhesive force of the said adhesive layer (B). Further, the present invention relates to a double-sided pressure-sensitive adhesive tape in which the gel fraction of the pressure-sensitive adhesive layer (A) is 30 to 60% by weight and the gel fraction of the pressure-sensitive adhesive layer (B) is 70% by weight or more.

  In addition, the present invention relates to the double-sided pressure-sensitive adhesive tape, wherein the base material is a film having an easy adhesion treatment surface on both sides.

  In the present invention, the pressure-sensitive adhesive layer (A) is formed from a pressure-sensitive adhesive (a) containing a hydroxyl group-containing pressure-sensitive resin, a hydroxyl group-containing tackifier resin, and a hydroxyl group-reactive curing agent. It relates to a double-sided adhesive tape.

  The present invention also relates to the double-sided pressure-sensitive adhesive tape, wherein the precursor of the hydroxyl group-containing adhesive resin contains 0.1 to 3.0% by weight of the hydroxyl group-containing monomer in 100% by weight of all monomers.

  Moreover, this invention relates to the said double-sided adhesive tape characterized by containing 10-60 weight part of hydroxyl-containing tackifying resin with respect to 100 weight part of hydroxyl-containing adhesive resin.

  The present invention also relates to the double-sided pressure-sensitive adhesive tape, wherein the pressure-sensitive adhesive layer (B) is formed from a pressure-sensitive adhesive (b) containing a carboxyl group-containing acrylic pressure-sensitive adhesive resin or a urethane pressure-sensitive adhesive resin.

  In the double-sided pressure-sensitive adhesive tape according to the invention, the precursor of the carboxyl group-containing acrylic adhesive resin contains 0.1 to 3.0% by weight of a carboxyl group-containing monomer in 100% by weight of all monomers. About.

  Moreover, this invention relates to the said double-sided adhesive tape characterized by containing a plasticizer 1 to 45 weight% in 100 weight% of adhesives (b).

  According to the present invention, even if a shearing process, a punching process, or the like is performed during the manufacturing process of the member, the adhesive is difficult to adhere to the member or the processing blade, and the double-sided adhesive tape having excellent heat resistance. Supply becomes possible.

The double-sided pressure-sensitive adhesive tape of the present invention comprises a pressure-sensitive adhesive layer (A), a base material, and a pressure-sensitive adhesive layer (B), and the pressure-sensitive adhesive force of the pressure-sensitive adhesive layer (A) is the pressure-sensitive adhesive force of the pressure-sensitive adhesive layer (B). The gel fraction of the pressure-sensitive adhesive layer (A) is 30 to 60% by weight, and the gel fraction of the pressure-sensitive adhesive layer (B) is 70% by weight or more.
In the present invention, an adhesive sheet, an adhesive tape, and an adhesive film are synonymous.

《Double-sided adhesive tape》
The double-sided pressure-sensitive adhesive tape of the present invention comprises a pressure-sensitive adhesive layer (A), a base material, and a pressure-sensitive adhesive layer (B), and the pressure-sensitive adhesive force of the pressure-sensitive adhesive layer (A) is higher than the pressure-sensitive adhesive force of the pressure-sensitive adhesive layer (B). And the gel fraction of an adhesive layer (A) is 30 to 60 weight%, and the gel fraction of an adhesive layer (B) is 70 weight% or more.

Since the adhesive strength of the pressure-sensitive adhesive layer (A) is higher than the adhesive strength of the pressure-sensitive adhesive layer (B), for example, the pressure-sensitive adhesive layer (A) is bonded to a stand or the like during the production process, and then the pressure-sensitive adhesive layer. After bonding the member to (B), it can be suitably used for applications that require removability to peel the member bonded to the pressure-sensitive adhesive layer (B). In addition, re-peelability is required for fixing to a table or the like during such a manufacturing process, and it can also be used for applications that require a strong adhesive force for fixing members. Can also be used for bonding and temporary fixing between members.
Since the pressure-sensitive adhesive layer (B) is a weak pressure-sensitive adhesive layer, it has a re-peelability that can be easily peeled off with respect to the peeling force, but is difficult to peel off against the shearing force in the lateral direction. It can also be used for applications such as automatically transporting parts in the horizontal direction.

  As a method for producing a double-sided pressure-sensitive adhesive tape, a pressure-sensitive adhesive layer (A) and a pressure-sensitive adhesive layer (B) are each applied to a release liner to form a pressure-sensitive adhesive layer, and then a substrate is bonded together (1). After the adhesive (a) is applied to the substrate to form the adhesive layer (A), the adhesive (b) is applied to the release liner to form the adhesive layer (B), or the substrate It is manufactured by the method (2) in which the pressure-sensitive adhesive (b) is applied to form a pressure-sensitive adhesive layer (B), and then the pressure-sensitive adhesive (a) is applied to the release liner to form the pressure-sensitive adhesive layer (A). it can. A double-sided pressure-sensitive adhesive tape can be produced by the above method or the like. The pressure-sensitive adhesive layer is usually protected with a release liner until just before using the pressure-sensitive adhesive tape.

  The pressure-sensitive adhesive (a) and the pressure-sensitive adhesive (b) are applied onto a release liner or substrate, for example, roll coater method, comma coater method, lip coater method, die coater method, reverse coater method, silk screen method, gravure coater. It can apply | coat by well-known methods, such as a method, Then, it can dry with a hot air oven, an infrared heater, etc., and can be set as an adhesive layer (A) and an adhesive layer (B).

1-50 micrometers is preferable and, as for the thickness of an adhesive layer (A) and an adhesive layer (B), 3-30 micrometers is more preferable.
By making an adhesive layer into the said range, it can be set as the double-sided adhesive tape excellent in workability.

  The release liner has a release layer formed by applying a release agent to a substrate such as paper, plastic, or synthetic paper. Examples of the release agent include silicone, alkyd resin, melamine resin, fluororesin, and acrylic resin. The re-peelable pressure-sensitive adhesive of the present invention has an effect that the peel force hardly depends on the type of the release agent. The thickness of the release liner is not particularly limited, but is about 10 to 150 μm.

<Adhesive layer (A)>
The pressure-sensitive adhesive layer (A) can be formed of a pressure-sensitive adhesive (a) described later, the pressure-sensitive adhesive force of the pressure-sensitive adhesive layer (A) is higher than the pressure-sensitive adhesive force of the pressure-sensitive adhesive layer (B), and the gel fraction. Is a pressure-sensitive adhesive layer of 30 to 60% by weight.

  Although it will not restrict | limit especially if the adhesive force of an adhesive layer (A) is higher than the adhesive force of an adhesive layer (B), Preferably, it is 5-30N of adhesive force, and 8-20N of adhesive force is more preferable.

Moreover, the gel fraction of an adhesive layer (A) is 30-60 weight%, Preferably, it is 35-55 weight%.
When the gel fraction of the pressure-sensitive adhesive layer (A) is 30% by weight or more, the pressure-sensitive adhesive is difficult to adhere to the member or the processing blade, and when the amount is 60% by weight or less, the pressure-sensitive adhesive is the member or the processing blade. It becomes difficult to adhere to the adhesive layer, and it becomes easier to obtain a higher adhesive force than the pressure-sensitive adhesive layer (B), whereby a double-sided tape excellent in processability can be obtained.

[Adhesive (a)]
The pressure-sensitive adhesive layer (A) can be formed of the pressure-sensitive adhesive (a). The pressure-sensitive adhesive (a) preferably contains a pressure-sensitive adhesive resin and a curing agent, and may contain a tackifier resin if necessary.

  A pressure-sensitive adhesive containing a hydroxyl group-containing adhesive resin, a hydroxyl group-containing tackifier resin, and a hydroxyl group-reactive curing agent is preferable because of excellent adhesive strength and processability.

(Adhesive resin)
Examples of the adhesive resin used in the pressure-sensitive adhesive layer (A) include acrylic adhesive resins, urethane adhesive resins, silicone adhesive resins, and elastomer resins such as rubber. Preferably, acrylic adhesives are used. Resin. Moreover, it is preferable that it is a hydroxyl-containing adhesive resin.

"Acrylic adhesive resin"
The acrylic adhesive resin is a (meth) acrylic polymer that can be synthesized using an acrylic monomer as a precursor, and a hydroxyl group-containing monomer is preferably used.
Examples of the monomer that is a precursor of the acrylic adhesive resin include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, propyl (meth) acrylate, pentyl (meth) acrylate, ( Hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, lauryl (meth) acrylate, (Meth) acrylamide, vinyl acetate, acrylonitrile and the like can be mentioned.
Furthermore, examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, glycidyl (meth) acrylate, N-methylolacrylamide, and hydroxypropyl. Examples include (meth) acrylate.
These monomers may be used alone or in combination of two or more.

  Among these, from the viewpoint of moderate crosslinkability with a curing agent, a hydroxyl group-containing monomer having an alkylene group having 1 to 3 carbon atoms is preferable because it can further improve cohesion and heat resistance. Of these, 2-hydroxyethyl (meth) acrylate is more preferable.

  Further, the content of the hydroxyl group-containing monomer is preferably 0.1 to 3.0% by weight and more preferably 0.3 to 1.5% by weight in 100% by weight of all monomers constituting the acrylic adhesive resin. preferable. When it is 0.1% by weight or more, the pressure-sensitive adhesive is difficult to adhere to the member or the processing blade, and when it is 3.0% by weight or less, the pressure-sensitive adhesive is difficult to adhere to the member or the processing blade. It becomes easier to obtain a higher adhesive strength than the layer (B).

  When synthesizing the acrylic adhesive resin, a polymerization method such as solution polymerization, emulsion polymerization, bulk polymerization, or polymerization by ultraviolet irradiation can be used, but in the present invention, solution polymerization with easy reaction control and physical property control is used. It is preferable.

  For the copolymerization, conventionally known polymerization initiators such as peroxide polymerization initiators and azobis polymerization initiators can be used. Examples of the organic peroxide polymerization initiator include benzoyl peroxide, di-t-butyl peroxide, cumene hydroperoxide, t-butyl peroxybenzoate, t-butyl peroxyneodecanoate, and t-butyl. Peroxy 2-ethylhexanoate and the like. As the azo polymerization initiator, 2,2′-azobisisobutyronitrile, 2,2′-azobis (2-amidinopropane) dihydrochloride, 2 , 2′-azobis [2- (5-methyl-2-imidazolin-2-yl) propane] dihydrochloride, 2,2′-azobis (2-methylpropionamidine) disulfate, 2,2′-azobis ( N, N′-dimethyleneisobutylamidine) and the like. These polymerization initiators may be used alone or in combination of two or more.

The weight average molecular weight of the adhesive resin is preferably 300,000 to 1,500,000, more preferably 500,000 to 1,200,000. By being 300,000 or more, the pressure-sensitive adhesive is difficult to adhere to the member or the processing blade, and by setting it to 1,500,000 or less, the pressure-sensitive adhesive is difficult to adhere to the member, the processing blade, etc. than the pressure-sensitive adhesive layer (B). Easy to obtain high adhesive strength.
In addition, in this invention, the weight average molecular weight of resin is the weight average molecular weight of polystyrene conversion calculated | required by GPC measurement.

(Tackifying resin)
In the present invention, the pressure-sensitive adhesive (a) may contain a tackifying resin, and preferably contains a hydroxyl group-containing tackifying resin.
The tackifying resin is preferably used in an amount of 10 to 60 parts by weight and more preferably 15 to 50 parts by weight with respect to 100 parts by weight of the adhesive resin. By being 10 parts by weight or more, the pressure-sensitive adhesive hardly adheres to the member or the processing blade, and by setting it to 60 parts by weight or less, the pressure-sensitive adhesive hardly adheres to the member or the processing blade, etc., and the pressure-sensitive adhesive layer (B) It is easier to obtain higher adhesive strength.

  Examples of tackifier resins include rosin esters, polymerized rosins, hydrogenated rosins, disproportionated rosins, maleic acid-modified rosins, fumaric acid-modified rosins, rosin phenol resins and the like; α-pinene resins, β- Terpene resins such as pinene resin, dipentene resin, aromatic modified terpene resin, hydrogenated terpene resin, terpene phenol resin, acid-modified terpene resin, and styrenated terpene resin. Further, coumarone-indene resin, styrene resin, alkylphenol resin, petroleum resin, and the like are exemplified, but the present invention is not limited to these, and such tackifying resins may be used in combination of two or more. .

  Examples of the hydroxyl group-containing tackifying resin include Pencel D-125 (Arakawa Chemical Co., hydroxyl value 30 to 40) and Pencel D-135 (Arakawa Chemical Co., hydroxyl value). 30-40), Pencel D-160 (Arakawa Chemical Co., Ltd., hydroxyl value 30-40), and the like. As a pine crystal series made by Arakawa Chemical Co., Ltd., Pine Crystal KE359 (Arakawa Chemical Co., Ltd., hydroxyl value 38-38). 47), Pine Crystal D-6011 (Arakawa Chemical Co., hydroxyl value 110-125), Pine Crystal KE-615-3 (Arakawa Chemical Co., hydroxyl value 53-66), Yasuhara Chemical YS Polystar series YS polystar K140 (manufactured by Yasuhara Chemical Co., hydroxyl value 200-220), YS polystar K125 (ya Hara Chemical Co., hydroxyl value 200-220), YS Polystar T160 (Yasuhara Chemical Co., hydroxyl value 60-70), YS Polystar T145 (Yasuhara Chemical Co., hydroxyl value 60-70), YS Polystar T130 (Yasuhara Chemical Co., Ltd., Hydroxyl value 60-70), YS polystar T115 (manufactured by Yasuhara Chemical Co., hydroxyl value 60-70), YS polystar T100 (manufactured by Yasuhara Chemical Co., hydroxyl value 60-70), YS polystar T80 (manufactured by Yasuhara Chemical Co., hydroxyl value 60-70) ), YS Polystar U130 (manufactured by Yasuhara Chemical Co., hydroxyl value 25-30), YS Polystar U115 (manufactured by Yashara Chemical Co., hydroxyl value 25-30), and the like, but are limited to these if it contains a hydroxyl group. Among these, without Pen cell series (manufactured by Arakawa Chemical Industries, Ltd.) are more preferable, to require transparency, Pine Crystal series (manufactured by Arakawa Chemical Industries, Ltd.) is preferable. These hydroxyl group-containing tackifying resins may be used alone or in combination of two or more.

(Curing agent)
The pressure-sensitive adhesive of the present invention preferably contains a curing agent. As the curing agent capable of reacting with the adhesive resin used for the adhesive (a), polyisocyanate compounds, aziridine compounds, metal chelate compounds, epoxy compounds and the like are preferable. Moreover, it is preferable that it is a hydroxyl group reactive hardening | curing agent.

  Examples of the polyisocyanate compound include tolylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, tetramethylxylylene diisocyanate, naphthalene diisocyanate, and triphenylmethane triisocyanate. Isocyanates, polyisocyanate compounds such as polymethylene polyphenyl isocyanate, adducts and burettes of these isocyanate compounds and polyol compounds such as trimethylolpropane, isocyanurates, and also these isocyanate compounds and known polyether polyols Polyester polyol, acrylic polio Le, polybutadiene polyols, adducts, etc. and polyisoprene polyol and the like.

  Examples of the aziridine compound include N, N′-hexamethylene-1,6-bis (1-aziridinecarboxamide, trimethylolpropane-tri-β-aziridinylpropionate, N, N′-diphenylmethane 4, 4′-bis (1-aziridinecarboxamide), trimethylolpropane-tri-β- (2-methylaziridine) propionate and the like can be mentioned.

  As the metal chelate compound, for example, a metal complex compound can be used. Examples of the metal include nickel, aluminum, chromium, iron, titanium, zinc, cobalt, manganese, copper, tin, and zirconium. Examples of the metal chelate compound include ferric trisacetylacetonate, aluminum trisacetylacetonate, aluminum monoacetylacetonate bis (ethylacetoacetate), and aluminum tris (ethylacetoacetate).

  Examples of the epoxy compound include bisphenol A, epichlorohydrin type epoxy resin, ethylene glycidyl ether, polyethylene glycol diglycidyl ether, glycerin diglycidyl ether, glycerin triglycidyl ether, 1,6-hexanediol glycidyl ether, trimethylolpropane tri Examples include glycidyl ether, diglycidyl aniline, diamine glycidyl amine, N, N, N ′, N′-tetraglycidyl-m-xylylenediamine, 1,3-bis (N, N′-diamine glycidylaminomethyl) cyclohexane, and the like. It is done.

  These curing agents may be used alone or in combination of two or more.

  Among these, as the hydroxyl group reactive curing agent, a polyisocyanate compound is preferable, and a trimethylolpropane adduct of xylene diisocyanate is more preferable.

  In this invention, it is preferable to use 0.1-10.0 weight part as a hardening | curing agent used for an adhesive (a) with respect to 100 weight part of adhesive resins, 0.5-5.0 weight Part is more preferred. When the amount is 0.1 parts by weight or more, the adhesive does not easily adhere to the member or the processing blade, and when the amount is 10.0 parts by weight or less, the adhesive hardly adheres to the member or the processing blade. It becomes easier to obtain a higher adhesive strength than the layer (B).

(Other ingredients)
In the pressure-sensitive adhesive (a), as other components, fillers, pigments, dyes, diluents, anti-aging agents, polymerization inhibitors, ultraviolet absorbers, ultraviolet light stabilizers, which are blended in known pressure-sensitive adhesives as necessary. Various additives such as a coupling agent may be included, and two or more kinds may be used. Moreover, the addition amount of an additive should just be taken as the quantity from which a required physical property is obtained, and is not specifically limited.

<Adhesive layer (B)>
The pressure-sensitive adhesive layer (B) can be formed from a pressure-sensitive adhesive (b) described later, and the pressure-sensitive adhesive layer (A) has a higher adhesive force than the pressure-sensitive adhesive layer (B) and has a gel fraction. Is a pressure-sensitive adhesive layer of 70% or more.

  The adhesive strength of the pressure-sensitive adhesive layer (B) is not particularly limited as long as the pressure-sensitive adhesive strength of the pressure-sensitive adhesive layer (A) is higher. However, in order to have removability, preferably the adhesive strength is 0.005 to 0.30 N. Yes, 0.01 to 0.20 N is more preferable.

Moreover, the gel fraction of an adhesive layer (B) is 70 weight% or more. Therefore, it is 70-100 weight%, More preferably, it is 80-100 weight%.
When the gel fraction of the pressure-sensitive adhesive layer (B) is 70% by weight or more, it is difficult for the pressure-sensitive adhesive to adhere to a member, a processing blade or the like, and it is easy to obtain a lower adhesive force than the pressure-sensitive adhesive layer (A). Peelability is easily obtained.

[Adhesive (b)]
The pressure-sensitive adhesive layer (B) can be formed of the pressure-sensitive adhesive (b). The pressure-sensitive adhesive (b) preferably contains a pressure-sensitive resin and a curing agent, and may contain a tackifier resin as necessary. It is also preferable to include a plasticizer.

  Preferably, the pressure-sensitive adhesive is a pressure-sensitive adhesive containing a carboxyl group-containing acrylic pressure-sensitive adhesive resin or a urethane pressure-sensitive adhesive resin. By using the said adhesive resin, it can be set as the double-sided adhesive sheet excellent in removability and workability. Particularly preferred is the case containing a carboxyl group-containing adhesive resin and a carboxyl group-reactive curing agent.

(Adhesive resin)
Examples of the adhesive resin used for the pressure-sensitive adhesive layer (B) include acrylic adhesive resins, urethane adhesive resins, silicon adhesive resins, and elastomer resins such as rubber. Adhesive resins and urethane adhesive resins are preferred, and carboxyl group-containing acrylic adhesive resins are more preferred.

"Acrylic adhesive resin"
The acrylic adhesive resin is a (meth) acrylic polymer that can be synthesized using an acrylic monomer as a precursor, and a carboxyl group-containing monomer is preferably used. The carboxyl group-containing monomer is not limited as long as it has a carboxyl group.
Examples of the monomer that is a precursor of the acrylic adhesive resin include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, propyl (meth) acrylate, pentyl (meth) acrylate, ( Hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, lauryl (meth) acrylate, (Meth) acrylamide, vinyl acetate, acrylonitrile and the like can be mentioned.
Furthermore, examples of the carboxyl group-containing monomer include (meth) acrylic acid, itaconic acid, maleic acid and the like.
These monomers may be used alone or in combination of two or more.

  Further, the content of the carboxyl group-containing monomer is preferably 0.1 to 3.0% by weight in 100% by weight of all monomers constituting the acrylic adhesive resin, and 0.3 to 2.0% by weight. More preferred. By being 0.1% by weight or more, the pressure-sensitive adhesive is difficult to adhere to a member, a processing blade or the like, and an adhesive force lower than that of the pressure-sensitive adhesive layer (A) is easily obtained. By adjusting the content to 3.0% by weight or less, the pressure-sensitive adhesive hardly adheres to the member, the processing blade, and the like, and it is easy to obtain a balance between the adhesive force and the removability.

  When synthesizing the acrylic adhesive resin, a polymerization method such as solution polymerization, emulsion polymerization, bulk polymerization, or polymerization by ultraviolet irradiation can be used, but in the present invention, solution polymerization with easy reaction control and physical property control is used. It is preferable.

  For the copolymerization, conventionally known polymerization initiators such as peroxide polymerization initiators and azobis polymerization initiators can be used. Examples of the organic peroxide polymerization initiator include benzoyl peroxide, di-t-butyl peroxide, cumene hydroperoxide, t-butyl peroxybenzoate, t-butyl peroxyneodecanoate, and t-butyl. Peroxy 2-ethylhexanoate and the like. As the azo polymerization initiator, 2,2′-azobisisobutyronitrile, 2,2′-azobis (2-amidinopropane) dihydrochloride, 2 , 2′-azobis [2- (5-methyl-2-imidazolin-2-yl) propane] dihydrochloride, 2,2′-azobis (2-methylpropionamidine) disulfate, 2,2′-azobis ( N, N′-dimethyleneisobutylamidine) and the like. These polymerization initiators may be used alone or in combination of two or more.

  The weight average molecular weight of the acrylic adhesive resin is preferably 100,000 to 1,500,000, and more preferably 200,000 to 1,000,000. By being 100,000 or more, the pressure-sensitive adhesive (B) hardly adheres to a member, a processing blade or the like, and an adhesive force lower than that of the pressure-sensitive adhesive layer (A) is easily obtained. By being 1.5 million or less, it is difficult for the adhesive to adhere to the member, the processing blade, etc., and it is easy to obtain a balance between adhesive force and removability.

"Urethane adhesive resin"
The urethane adhesive resin can be obtained by synthesizing a polyol and a polyisocyanate. The polyol is preferably polyester polyol, polyether polyol, polycarbonate polyol, acrylic polyol or the like.

The polyester polyol is obtained by synthesizing an acid component and a glycol component.
Examples of the acid component include terephthalic acid, adipic acid, azelaic acid, sebacic acid, phthalic anhydride, isophthalic acid, trimellitic acid, and the like.
Examples of the glycol component include ethylene glycol, propylene glycol, diethylene glycol, butylene glycol, 1,6-hexane glycol, 3-methyl-1,5-pentanediol, 3,3′-dimethylol heptane, polyoxyethylene glycol, poly Examples of the oxypropylene glycol, 1,4-butanediol, neopentyl glycol, butylethylpentanediol, and polyol component include glycerin, trimethylolpropane, and pentaerythritol. Other examples include polyester polyols obtained by ring-opening polymerization of lactones such as polycaprolactone, poly (β-methyl-γ-valerolactone), and polyvalerolactone.

  The number average molecular weight of the polyester polyol is preferably 500 to 5,000. When the number average molecular weight is 500 or more, the reaction control during the synthesis becomes easier, and when the number average molecular weight is 5,000 or less, the time until the completion of the reaction is easily shortened. The removability is further improved by easily maintaining the cohesive force. It is preferable that polyester polyol is 10-70 mol% among the total 100 mol% of the polyol used for the synthesis | combination of urethane adhesive resin.

  Examples of the polyether polyol include polypropylene glycol, polyethylene glycol, and polytetramethylene glycol. The polyether polyol can be produced by polymerizing a cyclic ether compound using a low molecular weight polyol as an initiator. Examples of the low molecular weight polyol include propylene glycol, ethylene glycol, glycerin and trimethylolpropane. Examples of the cyclic ether compound include ethylene oxide, propylene oxide, butylene oxide, and tetrahydrofuran.

  The number average molecular weight of the polyether polyol is preferably 1,000 to 5,000. When the number average molecular weight is 1,000 or more, it becomes easier to control the reaction at the time of synthesis, and when the number average molecular weight is 5,000 or less, the time until completion of the reaction can be easily shortened. The removability is further improved by easily maintaining the cohesive strength of the layer. Further, the polyether polyol usually has two hydroxyl groups, but can also have three or more hydroxyl groups. When a polyether polyol having three or more hydroxyl groups is used, the cohesive force of the pressure-sensitive adhesive layer can be easily adjusted. As for polyether polyol, 30-90 mol% is preferable among the total 100 mol% of the polyol used for the synthesis | combination of urethane adhesive resin.

  Examples of the polycarbonate polyol include polytrimethylene carbonate diol, polyhexamethylene carbonate diol, poly 3-methyl (pentamethylene) carbonate diol, and copolymers thereof, as well as ethylene glycol and 1,3-trimethylene glycol. 1,4-butanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,18 -Polycarbonate diol obtained by the dealcoholization reaction etc. of polyhydric alcohols, such as octadecanediol, and dialkyl carbonates, such as diethylene carbonate and dimethyl carbonate, etc. are mentioned.

  In the present invention, the use of a polyester polyol and a polyether polyol together with the polyol makes it easy to control the peeling force and the adhesive force.

  A known compound can be used as the polyisocyanate. Specifically, aromatic polyisocyanate, aliphatic polyisocyanate, araliphatic polyisocyanate, alicyclic polyisocyanate, and the like are preferable.

  Aromatic polyisocyanates include, for example, 1,3-phenylene diisocyanate, 4,4′-diphenyl diisocyanate, 1,4-phenylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6-triylene diisocyanate. 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. are mentioned.

  Aliphatic polyisocyanates include, for example, trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, dodecamethylene diisocyanate, 2, Examples include 4,4-trimethylhexamethylene diisocyanate.

  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 the alicyclic polyisocyanate include 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate, 1,3-cyclopentane diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, and methyl-2,4. -Cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 4,4'-methylenebis (cyclohexyl isocyanate), 1,4-bis (isocyanatemethyl) cyclohexane, 1,4-bis (isocyanatemethyl) cyclohexane and the like.

  A catalyst can be appropriately used for the synthesis of the urethane adhesive resin. The reaction time can be shortened by using a catalyst. The catalyst is preferably a tertiary amine compound or an organometallic compound.

  Examples of the tertiary amine compound include triethylamine, triethylenediamine, 1,8-diazabicyclo (5,4,0) -undecene-7 (DBU) and the like.

Examples of the organometallic compound include a tin compound and a non-tin compound.
Examples of tin compounds include dibutyltin dichloride, dibutyltin oxide, dibutyltin dibromide, dibutyltin dimaleate, dibutyltin dilaurate (DBTDL), dibutyltin diacetate, dibutyltin sulfide, tributyltin sulfide, tributyltin oxide, tributyltin acetate. , Triethyltin ethoxide, tributyltin ethoxide, dioctyltin oxide, tributyltin chloride, tributyltin trichloroacetate, tin 2-ethylhexanoate and the like.

  Examples of the non-tin compound include titanium compounds such as dibutyltitanium dichloride, tetrabutyltitanate, butoxytitanium trichloride, lead compounds such as lead oleate, lead 2-ethylhexanoate, lead benzoate, lead naphthenate, 2- Examples include iron compounds such as iron ethylhexanoate and iron acetylacetonate, cobalt compounds such as cobalt benzoate and cobalt 2-ethylhexanoate, zinc compounds such as zinc naphthenate and zinc 2-ethylhexanoate, and zirconium naphthenate. It is done.

  The catalyst is preferably used in an amount of about 0.01 to 1 part by weight based on 100 parts by weight of the total of polyol and polyisocyanate.

  In the present invention, it is preferable to synthesize a urethane pressure-sensitive adhesive resin by using a polyester polyol and a polyether polyol together. However, since both polyols have different reactivity, it is preferable to use a catalyst suitable for each polyol.

  For the synthesis of the urethane adhesive resin, (1) a method in which a polyol, a catalyst, and a polyisocyanate are all charged in a flask and reacted, (2) a method in which a polyol and a catalyst are charged in a flask and a polyisocyanate is dropped and reacted are preferable. .

  A known solvent can be used for the synthesis of the urethane adhesive resin. Specific examples include methyl ethyl ketone, ethyl acetate, toluene, xylene and acetone.

  The weight average molecular weight (Mw) of the urethane adhesive resin is preferably 30,000 to 400,000, and more preferably 50,000 to 300,000. Heat resistance improves because a weight average molecular weight becomes 30,000 or more. Moreover, re-peelability improves more by becoming 400,000 or less.

(Tackifying resin)
As the pressure-sensitive adhesive (b), a tackifying resin can be used as needed within a range not impairing the required performance. Examples of tackifying resins include rosin resins such as rosin ester, polymerized rosin, hydrogenated rosin, disproportionated rosin, maleic acid modified rosin, fumaric acid modified rosin, rosin phenol resin; α-pinene resin, β-pinene resin Terpene resins such as dipentene resins, aromatic modified terpene resins, hydrogenated terpene resins, terpene phenol resins, acid-modified terpene resins, and styrenated terpene resins. Further, coumarone-indene resin, styrene resin, alkylphenol resin, petroleum resin, and the like are exemplified, but the present invention is not limited to these, and such tackifying resins may be used in combination of two or more. .

(Curing agent)
In the present invention, a polyisocyanate compound, an aziridine compound, a metal chelate compound, an epoxy compound, and the like can be used as the curing agent capable of reacting with the adhesive resin used for the adhesive (b).

  In the present invention, the curing agent used for the pressure-sensitive adhesive (b) is preferably 0.1 to 10 parts by weight with respect to 100 parts by weight of the pressure-sensitive resin when an acrylic pressure-sensitive adhesive resin is used. 5 to 5.0 parts by weight are more preferable. When the amount is 0.1 parts by weight or more, the pressure-sensitive adhesive is difficult to adhere to the member or the processing blade, and when the amount is 10.0 parts by weight or less, the pressure-sensitive adhesive is difficult to adhere to the member or the processing blade. Adhesive strength lower than that of the layer (A) is easily obtained. As urethane adhesive resin, it is preferable to use 5-30 weight part with respect to 100 weight part of adhesive resin, and 10-25 weight part is more preferable. By being 5 parts by weight or more, the pressure-sensitive adhesive hardly adheres to the member or the processing blade, and by setting it to 30 parts by weight or less, the pressure-sensitive adhesive hardly adheres to the member, the processing blade, etc., and the pressure-sensitive adhesive layer (A) It is easier to obtain a lower adhesive strength.

(Plasticizer)
Moreover, it is preferable that an adhesive layer (B) contains a plasticizer further.
When the adhesive resin is an acrylic adhesive resin, the content of the plasticizer is preferably 1 to 20 parts by weight and more preferably 3 to 15 parts by weight with respect to 100 parts of the acrylic adhesive resin. By being 1 part by weight or more, it is easy to obtain lower adhesive strength and removability than the pressure-sensitive adhesive layer (A). By being 20 parts by weight or less, the pressure-sensitive adhesive hardly adheres to the member, the processing blade or the like, and it is easy to obtain a balance between the adhesive force and the removability.
When adhesive resin is urethane adhesive resin, it is preferable that it is 15-45 weight part with respect to 100 parts of urethane adhesive resin, and 20-40 weight part is more preferable. By being 15 parts by weight or more, it is easy to obtain lower adhesive strength and removability than the pressure-sensitive adhesive layer (A). By being 45 parts by weight or less, the pressure-sensitive adhesive hardly adheres to a member, a processing blade, or the like, and it is easy to obtain a balance between adhesive force and removability. Any appropriate plasticizer can be adopted as the plasticizer as long as the effects of the present invention are not impaired.

  Examples of plasticizers include phthalate ester plasticizers, trimellitic ester plasticizers, adipate ester plasticizers, phosphate ester plasticizers, citrate ester plasticizers, sebacate ester plasticizers, Aceline ester plasticizer, maleate ester plasticizer, benzoate ester plasticizer, polyether polyester plasticizer, epoxy polyester plasticizer (epoxidized soybean oil, epoxidized linseed oil, etc.), polyester plasticizer (Such as low molecular weight polyesters composed of carboxylic acid and glycol), fatty acid ester plasticizers (such as low molecular esters composed of fatty acids and alcohols), dibasic acid ester plasticizers (such as low molecular weight esters composed of dibasic acids and alcohols) The plasticizer may be only one kind or two or more kinds. Yes. Among these, from the viewpoint of compatibility with the adhesive, the acrylic adhesive resin is preferably an epoxy polyester plasticizer, more preferably an epoxidized linseed oil. As the urethane adhesive resin, a fatty acid ester plasticizer is preferable.

(Other ingredients)
In the pressure-sensitive adhesive layer (B), as other components, fillers, pigments, dyes, diluents, anti-aging agents, polymerization inhibitors, UV absorbers, UV stabilizers, which are blended with known pressure-sensitive adhesives as necessary Various additives such as an agent and a coupling agent may be included, and two or more kinds may be used. Moreover, the addition amount of an additive should just be taken as the quantity from which a required physical property is obtained, and is not specifically limited.

<Base material>
As a base material, the member which can be used as base materials of adhesives, such as a nonwoven fabric, paper, a film (plastic film etc.), and synthetic paper, can be used. When using as a base material (core material) of a double-sided pressure-sensitive adhesive tape, a nonwoven fabric and a film are preferable. Examples of the film include polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate, PPS (polyphenylene sulfide), nylon, triacetyl cellulose, cycloolefin, polyimide, and polyamide.
The substrate of the present invention may be an optical member such as an antireflection (AR) film, a polarizing plate or a retardation plate, which is obtained by applying a desired coating solution to the film.

  Moreover, in order to improve adhesiveness with an adhesive layer, it is more preferable that it is a film provided with the easily bonding process surface on both surfaces. As the easy adhesion treatment, known methods such as a dry method for corona discharge and a wet method for coating with an anchor coating agent can be used. By using a film having an easy-adhesion treated surface on both sides, it is possible to obtain a double-sided pressure-sensitive adhesive tape with improved adhesion to the pressure-sensitive adhesive layer and excellent workability.

  Further, an antistatic layer may be provided. The antistatic layer is formed of a composition in which at least one of conductive carbon particles, conductive metal particles, and conductive polymer is blended with a resin as necessary, in addition to the antistatic agent described above. It is preferable to become. Alternatively, the antistatic layer can be formed by metal deposition or metal plating on the substrate.

  Although the thickness in particular of a base material is not restrict | limited, 5-300 micrometers is preferable.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the following examples. In the examples, “part” means “part by weight”, and “%” means “% by weight”.

Moreover, the measuring method of the weight average molecular weight of resin is as follows.
(Weight average molecular weight of resin)
The weight average molecular weight of the resin is the polystyrene equivalent weight average molecular weight determined by GPC measurement, and the GPC measurement conditions are as follows. Apparatus: SHIMADZUProminence (manufactured by Shimadzu Corporation) Column: TOSOH TSK-GEL GMHXL (manufactured by Tosoh Corporation) is used. Solvent: tetrahydrofuran, flow rate: 0.5 ml / min, temperature: 40 ° C., sample concentration: 0.1 wt%, sample injection amount: 100 μl.

  Then, the adhesive resin used by the Example and the comparative example and the manufacturing method of an adhesive are demonstrated.

<Adhesive resin>
(Adhesive resin 1)
In a four-necked flask equipped with a stirrer, thermometer, reflux condenser, dropping device, and nitrogen inlet tube, 42.9 parts by weight of butyl acrylate, 2.0 parts by weight of isobutyl acrylate, 2.5 parts by weight of methyl methacrylate in a nitrogen atmosphere Parts, 2.0 parts by weight of succin vinyl, 0.25 parts by weight of acrylamide, 0.35 parts by weight of 2-hydroxyethyl acrylate, ethyl acetate as a solvent, perbutyl O (t-butylperoxy 2-ethylhexanoate as an initiator) Eight) was charged in an appropriate amount. Separately, 42.9 parts by weight of butyl acrylate, 2.0 parts by weight of isobutyl acrylate, 2.5 parts by weight of methyl methacrylate, 2.0 parts by weight of succinic vinyl, 0.25 parts by weight of acrylamide, 0. An appropriate amount of 35 parts by weight, ethyl acetate and toluene as solvents, and perbutyl O (t-butylperoxy 2-ethylhexanoate) as an initiator was charged. Next, the flask was gradually heated, and after confirming the start of the reaction, the solution was dropped from the dropping tube over 1 hour. Furthermore, the reaction was continued at an internal temperature of about 80 ° C. for 8 hours. After completion of the reaction, the mixture was cooled and diluted with ethyl acetate and toluene to give a nonvolatile content of 45% and a viscosity of 5800 mPa.s. s, The solution of the adhesive resin 1 which is an acrylic adhesive resin of the weight average molecular weight 680000 was obtained.

(Adhesive resin 2-7)
The acrylic adhesives of Synthesis Examples 5 to 6 were the same as the adhesive resin 1 except that the acrylic monomer, other raw materials, and the blending amount (parts by weight) in the production of the adhesive resin 1 were changed as shown in Table 1. A solution of resin (adhesive resins 2-7) was obtained.

Abbreviations in Table 1 are described below.
BA: butyl acrylate IBA: isobutyl acrylate 2EHA: 2-ethylhexyl acrylate VAc: succin vinyl AAm: acrylic amide (carboxyl group-containing monomer)
AA: Acrylic acid (hydroxyl group-containing monomer)
HEA: 2-hydroxyethyl acrylate

(Adhesive resin 8)
In a four-necked flask equipped with a stirrer, thermometer, reflux condenser, dropping device, and nitrogen inlet tube, in a nitrogen atmosphere, 13.35 parts by weight of butyl acrylate, 36.20 parts by weight of 2-ethylhexyl acrylate, 0. 45 parts by weight, ethyl acetate as a solvent, and perbutyl O (t-butylperoxy 2-ethylhexanoate) as an initiator were charged in appropriate amounts. Separately, in a dropping tube, 13.35 parts by weight of butyl acrylate, 36.20 parts by weight of 2-ethylhexyl acrylate, 0.45 parts by weight of acrylic acid, ethyl acetate as a solvent, perbutyl O (t-butyl peroxy 2- A suitable amount of ethyl hexanoate was charged. Next, the flask was gradually heated, and after confirming the start of the reaction, the solution was dropped from the dropping tube over 1 hour. Furthermore, the reaction was continued at an internal temperature of about 80 ° C. for 8 hours. After completion of the reaction, the reaction mixture was cooled and diluted with ethyl acetate and toluene to give a nonvolatile content of 42% and a viscosity of 5200 mPa.s. s, The solution of the adhesive resin 8 which is an acrylic adhesive resin of the weight average molecular weight 880000 was obtained.

(Adhesive resin 9)
In a four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, a dropping device, and a nitrogen introduction tube, in a nitrogen atmosphere, 16.3 parts by weight of butyl acrylate, 23.45 parts by weight of 2-ethylhexyl acrylate, 19 .65 parts by weight, 0.6 parts by weight of acrylic acid, ethyl acetate as a solvent, and azobisisobutyronitrile as an initiator were charged in appropriate amounts. Separately, 16.3 parts by weight of butyl acrylate, 23.45 parts by weight of 2-ethylhexyl acrylate, 19.65 parts by weight of succinic vinyl, 0.6 parts by weight of acrylic acid, ethyl acetate as a solvent, azo as an initiator An appropriate amount of bisisobutyronitrile was charged. Next, the flask was gradually heated, and after confirming the start of the reaction, the solution was dropped from the dropping tube over 1 hour. Further, the reaction was continued at an internal temperature of about 80 ° C. for 12 hours. After completion of the reaction, the mixture was cooled and diluted with ethyl acetate and toluene to give a nonvolatile content of 40% and a viscosity of 2000 mPa.s. s, The solution of the adhesive resin 9 which is an acrylic adhesive resin of the weight average molecular weight 480000 was obtained.

(Adhesive resin 10)
In a four-necked flask equipped with a stirrer, reflux condenser, nitrogen inlet tube, thermometer, and dropping funnel, under a nitrogen atmosphere, polyester polyol P-1010 (bifunctional polyester polyol, hydroxyl value 112, number average molecular weight 1000, Kuraray) 81 parts by weight, polyether polyol G-3000B (trifunctional polyether polyol, hydroxyl value 56, number average molecular weight 3000, manufactured by Adeka) 101 parts by weight, hexamethylene diisocyanate (Sumitomo Bayer) 19 parts by weight, 134 parts by weight of toluene, 0.05 part by weight of dibutyltin dilaurate and 0.02 part by weight of tin 2-ethylhexanoate were charged as a catalyst. The flask was gradually warmed and reacted at about 90 ° C. for 2 hours. Then, the reaction was continued while confirming the disappearance of the isocyanate group. After confirming the disappearance, the reaction was immediately terminated by cooling. Next, toluene was added so that the nonvolatile content was 60%, and the viscosity was 3100 mPa.s. s, The solution of the adhesive resin 10 which is a urethane adhesive resin of the weight average molecular weight 145000 was obtained.

(Adhesive resin 11)
In a four-necked flask equipped with a stirrer, thermometer, reflux condenser, dropping device, and nitrogen inlet tube, under a nitrogen atmosphere, 38.12 parts by weight of butyl acrylate, 9.9 parts by weight of methyl acrylate, 1.98 parts by weight of acrylic acid Parts, ethyl acetate as a solvent, and azobisisobutyronitrile as an initiator were charged in appropriate amounts. Separately, 38.12 parts by weight of butyl acrylate, 9.9 parts by weight of methyl acrylate, 1.98 parts by weight of acrylic acid, ethyl acetate as a solvent, and azobisisobutyronitrile as an initiator were charged in appropriate amounts in a dropping tube. Next, the flask was gradually heated, and after confirming the start of the reaction, the solution was dropped from the dropping tube over 1 hour. Furthermore, the reaction was continued at an internal temperature of about 80 ° C. for 8 hours. After completion of the reaction, the reaction mixture was cooled and diluted with ethyl acetate and toluene to give a nonvolatile content of 30% and a viscosity of 5500 mPa.s. s, The solution of the adhesive resin 11 which is an acrylic polymer with a weight average molecular weight of 780000 was obtained.

<Adhesive>
(Adhesive (a-1))
25.9 parts by weight of Pencel D-125 (manufactured by Arakawa Chemical Co., Ltd.) with respect to 100 parts by weight of the adhesive resin 1 (nonvolatile content), as a curing agent, xylene diisocyanate trimethylolpropane adduct (nonvolatile content of 50% by weight) The pressure-sensitive adhesive (a-1) was obtained by blending 1.5 parts by weight of the ethyl acetate solution) in terms of non-volatile content and an appropriate amount of toluene as a solvent and stirring with a disper.

(Adhesive (a-2 to 9))
The adhesive (a-1) is the same as the adhesive (a-1) except that the adhesive resin, the curing agent, the type of tackifier resin, and the blending amount (non-volatile content part) are changed as described in Table 2. a-2 to 9) were obtained.

(Adhesive (b-1))
For 100 parts by weight of the adhesive resin 8 (non-volatile content), 1.0 part by weight of Silaace S-510 and a curing agent, aziridine compound 1 (2.2-bis (hydroxymethyl) butanol tris [3- (1 -Aziridinyl) proponate] (toluene of 5.0% by weight of non-volatile content, isopropyl alcohol (IPA) solution)) 1.0 parts by weight in terms of non-volatile content, an appropriate amount of toluene as a solvent, and stirred with a disper Agent (b-1) was obtained.

(Adhesive (b-2-14))
The adhesive resin, the curing agent, the plasticizer, the types of other components, and the blending amount (non-volatile part by weight) are the same as those of the adhesive (b-1) except that they are changed as described in Tables 3 and 4. Thus, pressure-sensitive adhesives (b-2 to 14) were obtained.

Abbreviations in Tables 2 to 4 are shown below.
[Curing agent]
Isocyanate compound 1: xylene diisocyanate trimethylolpropane adduct 75% by weight in terms of nonvolatile content of ethyl acetate solution isocyanate compound 2: hexamethylene diisocyanate trimethylolpropane adduct 75% by weight in terms of nonvolatile content of ethyl acetate solution isocyanate compound 3: tolylene diisocyanate Non-volatile content of trimethylolpropane adduct having a non-volatile content of 37.5% by weight in ethyl acetate solution Aziridine compound 1: 2.2-bis (hydroxymethyl) butanol tris [3- (1-aziridinyl) proponate] (non-volatile content 5 Non-volatile content of [wt% toluene, IPA solution] [tackifying resin]
Pencel D-125: (Rosin ester resin, manufactured by Arakawa Chemical Co., Ltd.)
Pencel D-135: (Rosin ester resin, manufactured by Arakawa Chemical Co., Ltd.)
[Plasticizer]
Chemisizer LE3000: (epoxy plasticizer, manufactured by Sanwa Synthetic Chemical Co., Ltd.)
IPM-R: (Fatty acid ester plasticizer, NOF Corporation)
EXCEPARL IPP: (Fatty acid ester plasticizer, manufactured by Kao Corporation)
[Others]
Sila Ace S-510: (Silane coupling agent, manufactured by JNC)
Irganox 1135: (hindered phenol antioxidant, manufactured by BASF)

[Example 1]
The pressure-sensitive adhesive (a-1) was applied to a 25 μm PET substrate having an easy adhesion treatment surface on both sides so that the thickness after drying was 10 μm, dried at 100 ° C. for 2 minutes, and then a release liner. Were pasted together. Subsequently, the pressure-sensitive adhesive (b-1) was applied to a 50 μm release liner so that the thickness after drying was 10 μm, dried at 100 ° C. for 2 minutes, and then the PET base material pressure-sensitive adhesive (a-1). The film was bonded to the surface on which no coating was applied, and left at 23 ° C.-50% for 1 week to obtain a double-sided pressure-sensitive adhesive tape.

[Examples 2 to 18, Comparative Examples 1 to 4]
A double-sided pressure-sensitive adhesive tape was obtained in the same manner as in Example 1 except that the types of the pressure-sensitive adhesive (a) and the pressure-sensitive adhesive (b) were changed as described in Tables 5 to 7.

[Example 19]
The pressure-sensitive adhesive (a-1) was applied to the easy-adhesion treated surface side of a 25 μm PET substrate having an easy-adhesion treated surface on one side so that the thickness after drying was 10 μm, and the temperature was 100 ° C. for 2 minutes. After drying, a release liner was bonded. Subsequently, the adhesive (b-2) was applied to a 50 μm release liner so that the thickness after drying was 10 μm, dried at 100 ° C. for 2 minutes, and then the PET base adhesive (a-1). The film was bonded to the surface on which no coating was applied, and left at 23 ° C.-50% for 1 week to obtain a double-sided pressure-sensitive adhesive tape.

<Physical properties of double-sided adhesive tape>
About the obtained double-sided adhesive tape, the physical-property value measurement was performed with the following method. Tables 5 to 7 show the results.

(Adhesive force)
The release liner on the non-measured side of the obtained double-sided pressure-sensitive adhesive tape was peeled off and a 25 μm PET base material was bonded, and then prepared as a sample having a width of 25 mm and a length of 100 mm. Next, in a 23 ° C.-50% RH atmosphere, the release liner opposite to the surface on which the PET base material is bonded is peeled off from the obtained sample, and the exposed adhesive layer is pressed once and again on a stainless steel plate with a 2 kg roller. After leaving for 24 hours, the adhesive strength of the pressure-sensitive adhesive layer (A) and the pressure-sensitive adhesive layer (B) was measured using a tensile tester under conditions of a peeling angle of 180 degrees and a peeling speed of 0.3 m / min.

(Adhesive strength after heating)
The obtained double-sided pressure-sensitive adhesive tape was allowed to stand for 10 minutes in an atmosphere at 150 ° C., then taken out and left for 1 hour in an atmosphere at 23 ° C.-50% RH. Next, the release liner on the surface not to be measured was peeled off, and a 25 μm PET base material was bonded, and then prepared as a sample having a width of 25 mm and a length of 100 mm. Next, in a 23 ° C.-50% RH atmosphere, the release liner opposite to the surface on which the PET base material is bonded is peeled off from the obtained sample, and the exposed adhesive layer is pressed once and twice on a stainless steel plate with a 2 kg roller. After leaving for 24 hours, the adhesive strength of the pressure-sensitive adhesive layer (A) and the pressure-sensitive adhesive layer (B) was measured using a tensile tester under conditions of a peeling angle of 180 degrees and a peeling speed of 0.3 m / min.

(Holding power)
The release liner on the non-measured side of the obtained double-sided pressure-sensitive adhesive tape was peeled off and a 25 μm PET base material was bonded, and then prepared as a sample having a width of 25 mm and a length of 100 mm. Next, in a 23 ° C.-50% RH atmosphere, the release liner opposite to the surface on which the PET base material was bonded from the obtained sample was peeled off 25 mm long × 25 mm wide, and 1-reciprocating with a 2 kg roll on a stainless steel plate, 23 It was allowed to stand for 20 minutes in an atmosphere of -50%. Then, set a weight of 1kg under an atmosphere of 80 ° C so that force is applied in the direction of 180 degrees. After 24 hours, how many millimeters the adhesive sheet has been displaced from the adherend or the number of seconds that have completely dropped And the holding power of the pressure-sensitive adhesive layer (A) and the pressure-sensitive adhesive layer (B) was measured.

(Gel fraction of adhesive layer)
The pressure-sensitive adhesive was applied to a 50 μm release liner so that the thickness after drying was 10 μm, dried at 100 ° C. for 2 minutes, and then the release liner was bonded to prepare a cast tape. Next, the obtained cast tape was prepared to have a width of 30 mm and a length of 100 mm and used as a sample.
The release liner on one side of the obtained sample was peeled off and attached to a weighed 300 mesh stainless steel wire mesh (weight W0). The other release liner was peeled off and weighed (weight W1). The sample attached to the stainless steel wire mesh was refluxed and extracted in ethyl acetate for 5 hours, then dried at 100 ° C. for 1 hour and weighed (W2), and the following formula was used to determine the pressure-sensitive adhesive layer (A) and pressure-sensitive adhesive layer. (B) The gel fraction was calculated for each.
Gel fraction (% by weight) = {(W2-W0) / (W1-W0)} × 100

<Evaluation of double-sided adhesive tape>
The obtained double-sided pressure-sensitive adhesive tape was evaluated for the removability, workability, and punchability of the pressure-sensitive adhesive layer (B) having removability by the following methods. Tables 5 to 7 show the evaluation results.

(Removability)
The obtained double-sided pressure-sensitive adhesive tape was allowed to stand for 10 minutes in an atmosphere at 150 ° C., then taken out and left for 1 hour in an atmosphere at 23 ° C.-50% RH. Next, the release liner of the pressure-sensitive adhesive layer (A surface) of the obtained double-sided pressure-sensitive adhesive tape was peeled off, and a 25 μm PET base material was bonded together, and then prepared as a sample having a width of 25 mm and a length of 100 mm. Next, the release liner was peeled off from the measurement sample, and the exposed pressure-sensitive adhesive layer was attached to a SUS plate, and then allowed to stand in a 23 ° C.-50% RH atmosphere for 24 hours. The double-sided pressure-sensitive adhesive tape was peeled off, and the peelability of the pressure-sensitive adhesive layer (B) was evaluated by visually evaluating the surface of the peeled SUS plate. The evaluation criteria are as follows.

A: The adhesive sheet can be peeled off without contaminating the SUS plate, which is very good.
○: The SUS plate was very slightly contaminated, but it was good.
Δ: The SUS plate was slightly contaminated, but there is no practical problem.
X: The SUS board was contaminated. (Not practical)

<Processability>
The obtained double-sided pressure-sensitive adhesive tape was prepared to have a width of 100 mm and a length of 100 mm. Next, the double-sided pressure-sensitive adhesive tape was subjected to pressure bonding for 1 hour under the conditions of 40 ° C. and 60 kg / cm ² , and the state where the pressure-sensitive adhesive layer protruded from the side surface of the double-sided pressure-sensitive adhesive tape was evaluated. The evaluation criteria are as follows.

A: The pressure-sensitive adhesive layer protruded less than 0.1 mm, but it was very good.
○ = Extrusion of the pressure-sensitive adhesive layer of 0.1 mm or more and less than 0.3 mm was found to be good.
Δ = 0.3 mm or more and less than 0.5 mm of the adhesive layer protruded, but there is no practical problem.
X = A pressure-sensitive adhesive layer of 0.5 mm or more cannot be used because it protrudes.

[Punching property]
Using a punching machine TH-2000 (manufactured by Mochizuki Seisakusho), the double-sided adhesive tape was punched continuously for 100 shots in a circle with a diameter of 10 mm, and the punching processability was evaluated. The evaluation criteria for punching workability are shown below.

◎ ・ ・ ・ No glue adheres to the blade, and the punched circular part of release paper can be peeled cleanly and lightly.
(Very good)
○ ... Although glue adheres to the blade, the punched circular part of release paper can be peeled cleanly and lightly. (Good)
Δ: Glue adheres to the blade, and there is a little resistance when peeling off the punched release paper, but there is no practical problem.
X: The glue is very attached to the blade, or the resistance when peeling the punched circular part of the release paper is large. (Not practical)

  From the results of Tables 5 to 7, the double-sided pressure-sensitive adhesive tape of the present invention has a pressure-sensitive adhesive layer (A) whose adhesive strength is higher than that of the pressure-sensitive adhesive layer (B), and the gel fraction of the pressure-sensitive adhesive layer (A). 30 to 60% by weight and the gel fraction of the pressure-sensitive adhesive layer (B) was 70% by weight or more, good results were obtained in workability and punchability. Therefore, the double-sided pressure-sensitive adhesive sheet of the present invention can improve productivity because the pressure-sensitive adhesive is less likely to adhere to the member and the processing blade. Furthermore, the double-sided pressure-sensitive adhesive sheet of the present invention also had good removability and heat resistance.

Claims (8)

A pressure-sensitive adhesive layer (A), a base material, and a pressure-sensitive adhesive layer (B) are provided.
The pressure-sensitive adhesive force of the pressure-sensitive adhesive layer (A) is higher than the pressure-sensitive adhesive force of the pressure-sensitive adhesive layer (B),
The double-sided pressure-sensitive adhesive tape wherein the pressure-sensitive adhesive layer (A) has a gel fraction of 30 to 60% by weight and the pressure-sensitive adhesive layer (B) has a gel fraction of 70% by weight or more.   The double-sided pressure-sensitive adhesive tape according to claim 1, wherein the base material is a film having an easy adhesion treatment surface on both sides.   The pressure-sensitive adhesive layer (A) is formed from a pressure-sensitive adhesive (a) containing a hydroxyl group-containing pressure-sensitive resin, a hydroxyl group-containing tackifier resin, and a hydroxyl group-reactive curing agent. Double-sided adhesive tape.   4. The double-sided pressure-sensitive adhesive tape according to claim 3, wherein the precursor of the hydroxyl group-containing adhesive resin contains 0.1 to 3.0% by weight of the hydroxyl group-containing monomer in 100% by weight of all monomers.   The double-sided pressure-sensitive adhesive tape according to claim 3 or 4, comprising 10 to 60 parts by weight of a hydroxyl group-containing tackifying resin with respect to 100 parts by weight of the hydroxyl group-containing adhesive resin.   The double-sided surface according to any one of claims 1 to 5, wherein the pressure-sensitive adhesive layer (B) is formed from a pressure-sensitive adhesive (b) containing a carboxyl group-containing acrylic pressure-sensitive resin or a urethane pressure-sensitive adhesive resin. Adhesive tape.   7. The double-sided pressure-sensitive adhesive tape according to claim 6, wherein the precursor of the carboxyl group-containing acrylic adhesive resin contains 0.1 to 3.0% by weight of the carboxyl group-containing monomer in 100% by weight of all monomers. The double-sided pressure-sensitive adhesive tape according to claim 6 or 7, further comprising 1 to 45% by weight of a plasticizer in 100% by weight of the pressure-sensitive adhesive (b).