TWI666287B - Adhesive tape - Google Patents

Abstract

An object of the present invention is to provide an adhesive tape that is difficult to peel even with a thin adhesive tape, and can exhibit high fixed-load peelability to a low-polar adherend such as a polypropylene (PP) board.

The present invention is an adhesive tape having an adhesive layer containing: a polymer component containing 60% by weight or more of a weight average molecular weight obtained by Living Radical Polymerization of 300,000. ~ 2 million acrylic polymers containing hydroxyl and / or carboxyl groups with a molecular weight distribution (Mw / Mn) of 1.05 ~ 2.5; rosin-based adhesives with hydroxyl and / or carboxyl groups that impart resin or terpenes with hydroxyl and / or carboxyl groups It is an adhesion-imparting resin; and a cross-linking agent.

Description

Adhesive tape

The present invention relates to an adhesive tape that is difficult to peel even with a thin adhesive tape and can exhibit high fixed-load peelability to a low-polar adherend such as a polypropylene (PP) board.

Adhesive tapes are used in various industrial fields because they can be easily joined.

In the construction field, the adhesive tape is used for temporary fixing of curing sheets, the bonding of interior materials, etc. In the automotive field, the adhesive tape is used for fixing interior parts such as seats and sensors, and side trims. In the field of electrical and electronic, adhesive tape is used for module assembly, the module is attached to the housing, etc.

With the increasing demand for miniaturization, thinning or lightening of parts, or resource saving in recent years, thinner adhesive tapes are required than before. However, there is a problem that a thin adhesive tape cannot obtain a sufficient adhesive force, and is liable to peel off when a fixed load is applied. Among them, there is no sufficient adhesion for low-polar adherends such as polypropylene (PP) resins and cycloolefin polymer resins used in automotive parts or parts of electrical and electronic equipment, or it is easy to peel off under load. problem.

On the other hand, as an adhesive for an adhesive tape, a polymer obtained by polymerizing a radical polymerizable monomer such as a vinyl monomer and an acrylic monomer is often used. As a type of radical polymerization, free radical polymerization is generally used. However, free radical polymerization cannot fully control the molecular weight and molecular The amount distribution, copolymer composition, etc., lead to the production of low molecular weight components, or homopolymers even in the case of copolymerization. Therefore, the presence of these components may cause the heat resistance of the adhesive tape to decrease, the cohesive force, etc., or the adhesive tape to change. It is easy to peel off and other disadvantages.

In contrast, as a more controlled radical polymerization, living radical polymerization (Living Radical Polymerization) is being studied. Since living radical polymerization is a polymerization that causes the molecular chain to grow without the polymerization reaction being hindered by side reactions such as termination reaction or chain transfer reaction, it is easy to control the molecular weight, molecular weight distribution, copolymer composition, and the like, thereby suppressing low molecular weight. Generation of ingredients, etc.

Patent Document 1 describes an adhesive containing a copolymer obtained by copolymerizing a monomer by a living radical polymerization method using an organic tellurium compound as a polymerization initiator, and describes that the adhesive exhibits heat resistance. Excellent effect.

However, it has been difficult to obtain sufficient adhesion with a thin adhesive tape to the extent desired in recent years, and in particular, it is difficult to obtain sufficient adhesion to a low-polar adherend such as a polypropylene (PP) board, and the industry is seeking for further improvement.

[Prior technical literature]

[Patent Literature]

Patent Document 1: Japanese Patent No. 5256515

An object of the present invention is to provide an adhesive tape that is difficult to peel off even a thin adhesive tape and can exhibit high fixed-load peelability to a low-polar adherend such as a polypropylene (PP) board.

The invention is an adhesive tape having an adhesive layer, the adhesive layer contains: Polymer component containing 60% by weight or more of hydroxyl- and / or carboxyl-containing acrylic acid having a weight average molecular weight of 300,000 to 2 million and a molecular weight distribution (Mw / Mn) of 1.05 to 2.5 obtained by living radical polymerization Polymer; rosin-based adhesion-imparting resin having a hydroxyl group and / or a carboxyl group; or terpene-based adhesion-imparting resin having a hydroxyl group and / or a carboxyl group; and a crosslinking agent.

Hereinafter, the present invention will be described in detail.

The present inventors have found that a hydroxyl- and / or carboxyl-containing acrylic polymer having a weight average molecular weight of 300,000 to 2 million and a molecular weight distribution (Mw / Mn) of 1.05 to 2.5 obtained by living radical polymerization has been found. The polymer component as the main component is blended with a rosin-based adhesion-imparting resin having a hydroxyl group and / or a carboxyl group, or a terpene-based adhesion-imparting resin having a hydroxyl group and / or a carboxyl group, and a cross-linking agent. A thin adhesive tape is also difficult to peel off, and an adhesive tape capable of exhibiting a high fixed-load peeling property to a low-polar adherend such as a polypropylene (PP) board, thereby completing the present invention.

The adhesive tape of the present invention has an adhesive layer containing 60% by weight or more of a weight average molecular weight obtained by living radical polymerization of 300,000 to 2 million and a molecular weight distribution (Mw / Mn) of 1.05. Polymer component of ~ 2.5 acrylic polymer containing hydroxyl and / or carboxyl group (hereinafter also referred to as "living radical polymerized acrylic polymer"); rosin-based adhesion-imparting resin containing hydroxyl and / or carboxyl group or containing Terpene-based adhesion-imparting resins for hydroxyl groups and / or carboxyl groups (hereinafter also referred to as "rosin-based adhesion-imparting resins" and "terpene-based adhesion-imparting resins"); and cross-linking agents.

The adhesive layer contains the living radically polymerizable acrylic polymer, the rosin-based adhesion-imparting resin or terpene-based adhesion-imparting resin, and a cross-linking agent, so that the adhesive tape of the present invention is a thin adhesive tape. It is difficult to peel off and exhibits high fixed-load peelability to low-polar adherends such as polypropylene (PP) boards.

The living radical polymerization acrylic polymer uses acrylic monomers such as (meth) acrylate or (meth) acrylic acid as raw materials, and through living radical polymerization, It is preferably an acrylic polymer obtained by living radical polymerization using an organic tellurium polymerization initiator.

Living radical polymerization is polymerization in which the molecular chain is grown without the polymerization reaction being hindered by side reactions such as termination reaction or chain transfer reaction. Since a polymer having a more uniform molecular weight and composition than that of free radical polymerization can be obtained by living radical polymerization, and the generation of low molecular weight components can be suppressed, the adhesive tape becomes difficult to peel off. (PP) Plates have improved fixed-load peelability for low-polar adherends.

FIG. 1 is a schematic diagram illustrating living radical polymerization. Living radical polymerization is polymerization in which the molecular chain is grown without the polymerization reaction being hindered by side reactions such as termination reaction or chain transfer reaction. Living radical polymerization is based on the fact that free radical species are not deactivated at the growing end, and the reaction is performed without generating new radical species during the reaction. In the middle of its reaction, all polymer chains polymerize while reacting with the monomers uniformly, and the composition of all polymers is approximately uniform. Therefore, the monomers 12 containing a hydroxyl group and / or a carboxyl group are included in the entire polymer of the living radical polymerization acrylic polymer 1. If such a living radically polymerizable acrylic polymer 1 is combined with a rosin-based adhesion-imparting resin having a hydroxyl group and / or a carboxyl group, or a terpene-based adhesion-imparting resin having a hydroxyl group and / or a carboxyl group, and a crosslinking agent, All polymers participate in cross-linking between polymer chains, or cross-linking of polymer chains and adhesion-imparting resins. Therefore, it is possible to obtain an adhesive tape that is difficult to peel even with a thin adhesive tape and exhibits a high fixed-load peeling property to a low-polar adherend such as a polypropylene (PP) board.

The effect of the present invention cannot be obtained using an acrylic polymer obtained by a conventional free radical polymerization.

FIG. 2 is a schematic diagram illustrating free radical polymerization. In free radical polymerization, radical species are continuously generated during the reaction to add monomers, and the polymerization is advanced. Therefore, in the free radical polymerization, a polymer 23 which grows a terminal radical inactivation and grows in the middle of the reaction, or a polymer 24 which grows by using a radical species newly generated in the reaction is generated. So if you use free freedom Group polymerization to produce an acrylic polymer containing a hydroxyl group and / or a carboxyl group results in a polymer having a relatively low molecular weight and not containing a monomer containing a hydroxyl group and / or a carboxyl group. That is, it is convenient to combine such a free radical polymerization acrylic polymer 2 with a rosin-based adhesion-imparting resin having a hydroxyl group and / or a carboxyl group, or a terpene-based adhesion-imparting resin having a hydroxyl group and / or a carboxyl group, and a crosslinking agent. Polymers of hydroxy and / or carboxyl monomers cannot participate in cross-linking between polymer chains, or cross-linking of polymer chains and adhesion-imparting resins. When a thin adhesive tape is attached to the adherend and a load is applied, it will peel off from a polymer part that does not contain a monomer containing a hydroxyl group and / or a carboxyl group that cannot participate in cross-linking, so it cannot be exerted. Fixed load peelability to low-polar adherends such as polypropylene (PP) boards.

Among living radical polymerizations, living radical polymerization using an organic tellurium polymerization initiator is different from other living radical polymerizations. It is not applicable to radical polymerizable monomers having polar functional groups such as hydroxyl or carboxyl groups. In the case of protection, the same initiator is used for polymerization to obtain a polymer having a uniform molecular weight and composition. Therefore, a radical polymerizable monomer having a polar functional group can be easily copolymerized.

The organic tellurium polymerization initiator is not particularly limited as long as it is generally used for living radical polymerization, and examples thereof include organic tellurium compounds and organic telluride compounds.

Examples of the organic tellurium compound include (methylhydrotelluryl-methyl) benzene, (1-methylhydrotelluryl-ethyl) benzene, (2-methylhydrotelluryl-propyl) benzene, 1-chloro-4- (methylhydrotelluryl-methyl) benzene, 1-hydroxy-4- (methylhydrotelluryl-methyl) benzene, 1-methoxy-4- (methylhydrotelluryl) -Methyl) benzene, 1-amino-4- (methylhydrotelluryl-methyl) benzene, 1-nitro-4- (methylhydrotelluryl-methyl) benzene, 1-cyano-4 -(Methylhydrotelluryl-methyl) benzene, 1-methylcarbonyl-4- (methylhydrotelluryl-methyl) benzene, 1-phenylcarbonyl-4- (methylhydrotelluryl-methyl) ) Benzene, 1-methoxycarbonyl-4- (methylhydrotelluryl-methyl) benzene, 1-phenoxycarbonyl-4- (methylhydrotelluryl-methyl) benzene, 1-sulfonyl -4- (methylhydrotelluryl-methyl) benzene, 1-trifluoromethyl-4- (methylhydrotelluryl-methyl) benzene, 1-chloro-4- (1- Methylhydrotelluryl-ethyl) benzene, 1-hydroxy-4- (1-methylhydrotelluryl-ethyl) benzene, 1-methoxy-4- (1-methylhydrotelluryl-ethyl) ) Benzene, 1-amino-4- (1-methylhydrotelluryl-ethyl) benzene, 1-nitro-4- (1-methylhydrotelluryl-ethyl) benzene, 1-cyano- 4- (1-methylhydrotelluryl-ethyl) benzene, 1-methylcarbonyl-4- (1-methylhydrotelluryl-ethyl) benzene, 1-phenylcarbonyl-4- (1-methyl Hydrogen telluryl-ethyl) benzene, 1-methoxycarbonyl-4- (1-methylhydrotelluryl-ethyl) benzene, 1-phenoxycarbonyl-4- (1-methylhydrotelluryl) -Ethyl) benzene, 1-sulfofluorenyl-4- (1-methylhydrotelluryl-ethyl) benzene, 1-trifluoromethyl-4- (1-methylhydrotelluryl-ethyl) benzene , 1-chloro-4- (2-methylhydrotelluryl-propyl) benzene, 1-hydroxy-4- (2-methylhydrotelluryl-propyl) benzene, 1-methoxy-4- ( 2-methylhydrotelluryl-propyl) benzene, 1-amino-4- (2-methylhydrotelluryl-propyl) benzene, 1-nitro-4- (2-methylhydrotelluryl- Propyl) benzene, 1-cyano-4- (2-methylhydrotelluryl-propyl) benzene, 1-methylcarbonyl-4- (2-methylhydrotelluryl-propyl) benzene, 1- Phenylcarbonyl-4- (2-methylhydrotelluryl-propyl) benzene, 1-methoxycarbonyl-4- (2-methylhydrotelluryl-propyl) benzene, 1-phenoxycarbonyl- 4- (2-methylhydrotelluryl-propyl) , 1-sulfonyl-4- (2-methylhydrotelluryl-propyl) benzene, 1-trifluoromethyl-4- (2-methylhydrotelluryl-propyl) benzene, 2- (formaldehyde) Hydrogen telluryl-methyl) pyridine, 2- (1-methylhydrotelluryl-ethyl) pyridine, 2- (2-methylhydrotelluryl-propyl) pyridine, 2-methylhydrotelluryl- Methyl acetate, 2-methylhydrotelluryl-methyl propionate, 2-methylhydrotelluryl-2-methylpropionate, 2-methylhydrotelluryl-ethyl acetate, 2-methyl Hydrogen telluryl-ethyl propionate, 2-methylhydrotelluryl-2-methylpropionate, 2-methylhydrotellurylacetonitrile, 2-methylhydrotellurylpropionitrile, 2-methyl- 2-methylhydrotellurylpropionitrile and the like. The methylhydrotelluryl groups in these organic tellurium compounds may also be ethylhydrotelluryl, n-propylhydrotelluryl, isopropylhydrotelluryl, n-butylhydrotelluryl, isobutylhydrotelluryl, Butylhydrotelluryl, phenylhydrotelluryl, etc. These organic tellurium compounds may be used alone or in combination of two or more.

Examples of the organic telluride compound include dimethyl ditelluride, diethyl ditelluride, di-n-propyl ditelluride, diisopropyl ditelluride, and dicyclopropyl. Ditelluride, di-n-butyl ditelluride, di-secondary butyl ditelluride, di-tertiary butyl di telluride, dicyclobutyl di telluride, diphenyl di telluride, bis (p-methoxy Phenyl) ditelluride, bis (p-aminophenyl) ditelluride, bis (p-nitrophenyl) ditelluride, bis (p-cyanophenyl) ditelluride, bis (p-sulfofluorenyl) Phenyl) ditelluride, dinaphthyl ditelluride, dipyridyl di telluride, and the like. These organic telluride compounds may be used alone or in combination of two or more. Among them, dimethyl ditelluride, diethyl ditelluride, di-n-propyl di telluride, di-n-butyl di telluride, and diphenyl di telluride are preferred.

In addition, as long as the effect of the present invention is not impaired, in addition to the above-mentioned organic tellurium polymerization initiator, an azo compound may be used as a polymerization initiator in order to accelerate the polymerization rate.

The azo compound is not particularly limited as long as it is generally used for radical polymerization, and examples thereof include 2,2'-azobis (isobutyronitrile) and 2,2'-azobis (2-methyl) Butyronitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile), 1,1-azobis (cyclohexane-1-carbonitrile), 1-[(1-cyano-1-methylethyl) azo ] Formamidine, 4,4'-azobis (4-cyanovaleric acid), 2,2'-azobis (2-methylpropionate), 1,1'-azobis (Dimethyl 1-cyclohexanecarboxylate), 2,2'-azobis {2-methyl-N- [1,1'-bis (hydroxymethyl) -2-hydroxyethyl) propaneamidine Amine}, 2,2'-azobis [2-methyl-N- (2-hydroxyethyl) propanamide], 2,2'-azobis [N- (2-propenyl) -2 -Methylpropionamine], 2,2'-Azobis (N-butyl-2-methylpropylamidamine), 2,2'-Azobis (N-cyclohexyl-2-methylpropyl) Hydrazine), 2,2'-azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride, 2,2'-azobis {2- [1- (2-hydroxy Ethyl) -2-imidazolin-2-yl] propane} dihydrochloride, 2,2'-azobis [2- (2-imidazolin-2-yl) propane], 2,2'- N-bis (2-fluorenylpropane) dihydrochloride, 2,2 ' -Azobis [N- (2-carboxyethyl) -2-methylpropylhydrazone] tetrahydrate, 2,2'-azobis (1-imino-1-pyrrolidinyl-2-methyl Propane) dihydrochloride, 2,2'-azobis (2,4,4-trimethylpentane) and the like. These azo compounds may be used alone or in combination of two or more.

Since the living radical polymerization acrylic polymer contains a hydroxyl group and / or a carboxyl group, an acrylic monomer having a hydroxyl group and / or a carboxyl group is blended as the acrylic monomer to be polymerized in the living radical polymerization.

Examples of the acrylic monomer having a hydroxyl group include (meth) acrylic acid esters having a hydroxyl group, such as 4-hydroxybutyl (meth) acrylate and 2-hydroxyethyl (meth) acrylate.

Examples of the acrylic monomer having a carboxyl group include (meth) acrylic acid. Among these, acrylic acid is suitable.

When the (meth) acrylate having a hydroxyl group is used, the content thereof is not particularly limited, and a preferable upper limit of the radical polymerizable monomer polymerized in the living radical polymerization is 30% by weight. If the content is more than 30% by weight, the gel fraction of the adhesive layer may become too high, and the adhesive tape may be easily peeled off, which may result in a decrease in the peelability of the adherend under a fixed load.

When the acrylic monomer having a carboxyl group is used, the content thereof is not particularly limited. A preferable lower limit of the radical polymerizable monomer polymerized in the living radical polymerization is 0.1% by weight, and a preferable upper limit is It is 10% by weight. If the content is less than 0.1% by weight, the adhesive layer may become too soft and the heat resistance may be reduced. When the said content exceeds 10 weight%, the said adhesive layer may become too hard, and an adhesive tape may peel easily.

As the acrylic monomer to be polymerized in the living radical polymerization, other radical polymerizable monomers other than the acrylic monomer having a hydroxyl group and / or a carboxyl group may be used. Examples of the other radical polymerizable monomer include other (meth) acrylates. In addition, an acrylic monomer having other polar functional groups such as an amine group, a sulfonylamine group, and a nitrile group may be used. Further, in addition to the above-mentioned acrylic monomer, a vinyl-based compound may be used as the monomer.

The other (meth) acrylates are not particularly limited, and examples thereof include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, (formyl) Base) tert-butyl acrylate, 2-ethylhexyl (meth) acrylate, (meth) propyl Alkyl (meth) acrylates such as n-octyl enoate, isooctyl (meth) acrylate, isononyl (meth) acrylate, isomyristyl (meth) acrylate, and stearyl (meth) acrylate Ester, or cyclohexyl (meth) acrylate, isoamyl (meth) acrylate, benzyl (meth) acrylate, 2-butoxyethyl (meth) acrylate, 2-benzene (meth) acrylate Oxyethyl ester, glycidyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, polypropylene glycol mono (meth) acrylate, and the like. These (meth) acrylates may be used alone or in combination of two or more.

The vinyl compound is not particularly limited, and examples thereof include N, N-dimethylacrylamide, N, N-diethylacrylamide, N-isopropylacrylamide, and N-hydroxyethyl (Meth) acrylamide compounds such as acrylamide, acrylamide, N-vinylpyrrolidone, N-vinylcaprolactam, N-vinylacetamide, N-acrylamidoline, Acrylonitrile, styrene, vinyl acetate, etc. These vinyl compounds may be used alone or in combination of two or more.

A dispersion stabilizer may also be used in the living radical polymerization. Examples of the dispersion stabilizer include polyvinyl pyrrolidone, polyvinyl alcohol, methyl cellulose, ethyl cellulose, poly (meth) acrylic acid, poly (meth) acrylate, and polyethylene glycol. Wait.

As the method of the living radical polymerization, a conventionally known method can be used, and examples thereof include solution polymerization (boiling point polymerization or constant temperature polymerization), emulsion polymerization, suspension polymerization, and block polymerization.

When a polymerization solvent is used in the above-mentioned living radical polymerization, the polymerization solvent is not particularly limited. For example, non-polar solvents such as hexane, cyclohexane, octane, toluene, and xylene; or water, methanol, Ethanol, propanol, butanol, acetone, methyl ethyl ketone, methyl isobutyl ketone, tetrahydrofuran, di Highly polar solvents such as alkane and N, N-dimethylformamide. These polymerization solvents may be used alone or in combination of two or more.

The polymerization temperature is preferably from 0 to 110 ° C from the viewpoint of the polymerization rate.

With regard to the living radical polymerized acrylic polymer, the lower limit of the weight average molecular weight (Mw) is 300,000, and the upper limit is 2 million. If the weight average molecular weight is less than 30 If the adhesive layer is too soft, the heat resistance is reduced. If the weight average molecular weight exceeds 2 million, the viscosity at the time of coating may be too high to make it difficult to apply, which may cause uneven thickness of the adhesive layer. The lower limit of the weight average molecular weight (Mw) of the living radical polymerized acrylic polymer is preferably 400,000, and the upper limit is 1.3 million.

The molecular weight distribution (Mw / Mn) of the living radical polymerized acrylic polymer is 1.05 to 2.5. When the molecular weight distribution exceeds 2.5, the low-molecular-weight components and the like generated in the living radical polymerization increase, so that the adhesive tape is easily peeled off, and the fixed-load peelability to the adherend is reduced. The preferable upper limit of the molecular weight distribution is 2.0, the more preferable upper limit is 1.8, and the more preferable upper limit is 1.7.

The molecular weight distribution (Mw / Mn) is a ratio of a weight average molecular weight (Mw) to a number average molecular weight (Mn).

The weight average molecular weight (Mw) and the number average molecular weight (Mn) were measured by a gel permeation chromatography (GPC) method in terms of molecular weight in terms of polystyrene. Specifically, the weight-average molecular weight (Mw) and number-average molecular weight (Mn) are obtained by filtering a diluted solution obtained by diluting a living radical polymerized acrylic polymer 50 times with tetrahydrofuran (THF) using a filter. The obtained filtrate was measured as a polystyrene-equivalent molecular weight by GPC method. In the GPC method, for example, 2690 Separations Model (manufactured by Waters) can be used.

The polymer component may contain a polymer other than the living radical polymerization acrylic polymer, for example, a polymer obtained by free radical polymerization.

Among them, it is preferable that the lower limit of the content of the living radical polymerized acrylic polymer in the polymer component is 60% by weight, and the total amount (100% by weight) of the polymer component is the living radical polymerized acrylic polymer. . By setting the content of the above-mentioned living radically polymerizable acrylic polymer in the polymer component to 60% by weight or more, it is possible to obtain a thin film that is difficult to peel off and can be used for low-polar adherends such as polypropylene (PP) boards. A higher fixed load peeling adhesive tape.

The above-mentioned rosin-based adhesion-imparting resin or terpene-based adhesion-imparting resin is not included in the polymer component.

The rosin-based adhesion-imparting resin or terpene-based adhesion-imparting resin contains a hydroxyl group and / or a carboxyl group.

When both the living radically polymerizable acrylic polymer and the adhesion-imparting resin have a hydroxyl group, the living radically polymerizable acrylic polymer and the adhesion-imparting agent are made by using, for example, an isocyanate-based crosslinking agent as a crosslinking agent. Both of the resins are crosslinked by a reaction through a crosslinking agent. When both the living radical polymerization acrylic polymer and the adhesion-imparting resin have a carboxyl group, for example, an epoxy-based crosslinking agent or an aziridine-based crosslinking agent is used as the crosslinking agent. Both the living radical polymerized acrylic polymer and the adhesion-imparting resin are cross-linked by a reaction through a cross-linking agent. Living radical polymerized acrylic polymers have a uniform composition of all polymers and have hydroxyl and / or carboxyl groups, so that all polymers can participate in cross-linking between polymer chains, or polymer chains and adhesion imparting to resins. Cross-linking. Therefore, it is possible to obtain an adhesive tape that is difficult to peel even with a thin adhesive tape and exhibits a high fixed-load peeling property to a low-polar adherend such as a polypropylene (PP) board.

Since it is easy to control the gel fraction and the adhesive property, it is particularly suitable for the combination of the above-mentioned living radically polymerized acrylic polymer and the adhesion-imparting resin having a hydroxyl group and using an isocyanate-based crosslinking agent as the crosslinking agent.

Regarding the above-mentioned rosin-based adhesion-imparting resin or terpene-based adhesion-imparting resin, a preferable lower limit of the hydroxyl value is 25, and a preferable upper limit is 55. When the said hydroxyl value exceeds the said range, the peeling property of the adhesive tape with respect to a low-polarity to-be-adhered body, such as a polypropylene (PP) board, under fixed load may fall. The more preferable lower limit of the above-mentioned hydroxyl value is 30, and the more preferable upper limit is 50.

The hydroxyl value can be measured by JIS K1557 (phthalic anhydride method).

Regarding the rosin-based adhesion-imparting resin or terpene-based adhesion-imparting resin, a preferable lower limit of the softening temperature is 70 ° C, and a preferable upper limit is 170 ° C. If the above softening temperature does not reach 70 ° C, In some cases, the above-mentioned rosin-based adhesion-imparting resin or terpene-based adhesion-imparting resin is too soft, which may result in a decrease in the peelability of a fixed load to a low-polar adherend such as a polypropylene (PP) board. If the softening temperature exceeds 170 ° C., the adhesive layer may become too hard, the adhesive tape may be easily peeled off, and the peeling property of a fixed load to a low-polar adherend such as a polypropylene (PP) board may be reduced. A more preferable lower limit of the softening temperature is 120 ° C.

The softening temperature refers to a softening temperature measured by the JIS K2207 ring and ball method.

The rosin-based adhesion-imparting resin or terpene-based adhesion-imparting resin is not particularly limited, and examples thereof include a rosin ester resin and a terpene phenol resin, and a rosin ester resin is preferred.

The above-mentioned rosin ester resin is obtained by esterifying a rosin resin containing rosin acid as a main component, a disproportionated rosin resin, a hydrogenated rosin resin, and a dimer of a resin acid such as rosin acid (polymerized rosin resin). The resin. Since a part of the hydroxyl groups of the alcohol used for the esterification is contained in the resin without being used for esterification, the hydroxyl value is adjusted to the above range. Examples of the alcohol include polyhydric alcohols such as ethylene glycol, glycerin, and neopentyl tetraol.

Furthermore, a resin obtained by esterifying a rosin resin is a rosin ester resin, a resin obtained by esterifying a disproportionated rosin resin is a disproportionated rosin ester resin, and a resin obtained by esterifying a hydrogenated rosin resin is a hydrogenated rosin ester. As the resin, a resin obtained by esterifying a polymerized rosin resin is a polymerized rosin ester resin.

The above-mentioned terpene phenol resin refers to a resin obtained by polymerizing a terpene in the presence of phenol.

Examples of the disproportionated rosin ester resin include SUPER ESTER A75 (hydroxyl value 23, softening temperature 75 ° C) manufactured by Arakawa Chemical Industries, and SUPER ESTER A100 (hydroxyl value 16, softening temperature 100 ° C) produced by Arakawa Chemical Industries. , SUPER ESTER A115 (hydroxyl value 19, softening temperature 115 ° C) manufactured by Arakawa Chemical Industries, SUPER ESTER A125 (hydroxyl value 15, softening temperature 125 ° C) manufactured by Arakawa Chemical Industries, etc. Examples of the hydrogenated rosin ester resin include PINECHRYSTALKE-359 (hydroxyl value 42, acid value 12, softening temperature 100 ° C) manufactured by Arakawa Chemical Industries, and ESTER manufactured by Arakawa Chemical Industries. GUMH (hydroxyl value 29, softening temperature 70 ° C) and the like. Examples of the polymerized rosin ester resin include: PENSEL D135 (hydroxyl number 45, acid value 13, softening temperature 135 ° C) manufactured by Arakawa Chemical Industry Co., Ltd .; PENSEL D125 (hydroxyl value 34, acid value 13) manufactured by Arakawa Chemical Industry Co., Ltd. , Softening temperature 125 ° C), PENSEL D160 (hydroxyl value 42, acid value 13, softening temperature 160 ° C) manufactured by Arakawa Chemical Industries, Ltd., etc.

Examples of the terpene-based adhesion-imparting resin include YS POLYSTER G150 (softening point 150 ° C) manufactured by YASUHARA CHEMICAL, YS POLYSTER T100 (softening point 100 ° C) manufactured by YASUHARA CHEMICAL, and YS POLYSTER manufactured by YASUHARA CHEMICAL G125 (softening point 125 ° C), YS POLYSTER T115 (softening point 115 ° C) manufactured by YASUHARA CHEMICAL company, YS POLYSTER T130 (softening point 130 ° C) manufactured by YASUHARA CHEMICAL company, POLYSTER U115 (softening point 115 ° C) manufactured by YASUHARA CHEMICAL company ), POLYSTER UH115 (softening point 115 ° C) manufactured by YASUHARA CHEMICAL, YS RESIN PX1250 (softening point 125 ° C) manufactured by YASUHARA CHEMICAL, etc.

These rosin-based adhesion-imparting resins or terpene-based adhesion-imparting resins may be used alone or in combination of two or more.

The content of the rosin-based adhesion-imparting resin or terpene-based adhesion-imparting resin is preferably 5 parts by weight with respect to 100 parts by weight of the living radically polymerizable acrylic polymer, and a preferable upper limit thereof is 40 parts by weight. When the content is less than 5 parts by weight, the adhesive tape may be easily peeled off, and the fixed-load peelability to a low-polar adherend such as a polypropylene (PP) board may be reduced. When the content exceeds 40 parts by weight, the adhesive layer may become too hard due to an increase in the glass transition temperature (Tg), and the adhesive tape may be easily peeled off.

The said crosslinking agent is not specifically limited, According to the combination of the said living radical polymerization acrylic polymer and a rosin-type adhesion-imparting resin or a terpene-type adhesion-imparting resin, a crosslinking agent which can cross-link these is suitably selected.

Examples of the crosslinking agent include an isocyanate-based crosslinking agent, an aziridine-based crosslinking agent, an epoxy-based crosslinking agent, and a metal chelate-type crosslinking agent. Among them, an isocyanate-based crosslinking agent is preferred because it has excellent adhesion stability to a substrate.

Examples of the isocyanate-based crosslinking agent include Coronate HX (manufactured by Japan Polyurethane Industry Co., Ltd.), Coronate L (manufactured by Japan Polyurethane Industry Co., Ltd.), and MITEC NY260A (manufactured by Mitsubishi Chemical Corporation).

The blending amount of the crosslinking agent is preferably 0.01 to 5 parts by weight, and more preferably 0.1 to 3 parts by weight, with respect to 100 parts by weight of the living radical polymerized acrylic polymer.

By appropriately adjusting the type or amount of the crosslinking agent, the gel fraction of the adhesive layer can be adjusted.

The above-mentioned adhesive layer may optionally contain other resins such as plasticizer, emulsifier, softener, filler, pigment, dye, silane coupling agent, antioxidant and other additives.

The adhesive layer preferably has a gel fraction of 70% by weight or less. If the gel fraction exceeds 70% by weight, the crosslink density of the above-mentioned adhesive layer becomes too high, the adhesive tape becomes easy to peel off, and a fixed load is applied to a low-polar adherend such as a polypropylene (PP) board. When peelability is reduced. The gel fraction is more preferably 60% by weight or less.

The lower limit of the gel fraction of the adhesive layer is not particularly limited. In terms of heat resistance and the like, it is preferably 1% by weight or more, and more preferably 10% by weight or more.

The gel fraction was measured as follows. First, the adhesive tape was cut into a flat rectangular shape of 50mm × 100mm to prepare a test piece. After immersing the test piece in ethyl acetate at 23 ° C for 24 hours, the test piece was taken out from the ethyl acetate and dried at 110 ° C. 1 hour. The weight of the dried test piece was measured, and the gel fraction was calculated using the following formula (1). In addition, the test piece is a release film which is not laminated to protect the adhesive layer.

Gel fraction (wt%) = 100 × (W2-W0) / (W1-W0) (1)

(W0: weight of substrate, W1: weight of test piece before immersion, W2: after immersion and drying (Weight of test piece)

Since the adhesive tape of the present invention is difficult to peel off even a thin adhesive tape, the above-mentioned adhesive layer and the following substrate can be made thin according to the application.

The thickness of the above-mentioned adhesive layer is not particularly limited because it is set according to the application, and the preferred lower limit is 1 μm, and the preferred upper limit is 100 μm. If the thickness is less than 1 μm, the adhesive tape may be easily peeled off, and the fixed-load peelability to a low-polar adherend such as a polypropylene (PP) board may be reduced. If the thickness is more than 100 μm, a thin adhesive tape may not be obtained. A more preferable lower limit of the thickness is 15 μm, and a more preferable upper limit is 75 μm.

The adhesive tape of the present invention may be a support type with a substrate or a non-support type without a substrate. In the case of a supporting type, the above-mentioned adhesive layer may be formed on one side of the substrate, or the above-mentioned adhesive layer may be formed on both sides.

The substrate is not particularly limited, and examples thereof include a resin film, a resin foam, paper, a nonwoven fabric, and a gauze.

Examples of the resin film include polyolefin resin films such as polyethylene films and polypropylene films, polyester resin films such as PET films, and modified olefins such as ethylene-vinyl acetate copolymers and ethylene-acrylate copolymers. Resin films, polyvinyl chloride resin films, polyurethane resin films, cycloolefin polymer resin films, and the like.

Examples of the resin foam include polyethylene foam, polypropylene foam, acrylic foam, urethane foam, and ethylene-propylene rubber foam.

Examples of the gauze include a knitted fabric made of a polyethylene flat yarn or a resin film laminated on a surface thereof.

In particular, in the case of a double-sided tape used when assembling a display module, a substrate printed in black to prevent light transmission, a substrate printed in white to improve light reflectivity, and a metal-deposited film can be used. Substrate.

The thickness of the above substrate is not particularly limited because it is set according to the application For example, in the case of a film substrate, it is preferably 1 to 100 μm, and more preferably 5 to 75 μm. If the thickness of the substrate is less than 1 μm, the mechanical strength of the adhesive tape may be reduced. If the thickness of the substrate is more than 100 μm, the toughness of the adhesive tape may become too strong, and it may be difficult to adhere and adhere along the shape of the adherend.

The method for producing the adhesive tape of the present invention is not particularly limited, and examples thereof include the above-mentioned living radical polymerizable acrylic polymer and the above-mentioned rosin-based adhesion-imparting resin or terpene-based adhesion-imparting resin and the above-mentioned cross-linking agent, etc. as necessary The blended ingredients are mixed and stirred together to prepare an adhesive solution, and then the adhesive solution is coated on a PET film subjected to mold release treatment, and dried to form an adhesive layer, so that the obtained adhesive layer is transferred. A method of sticking to one or both sides of a substrate; a method of directly coating and drying a substrate. It is also possible to apply the adhesive solution to the PET film that has undergone the release treatment and dry it, and then use the formed adhesive layer as a non-supporting type adhesive tape without a substrate.

The application of the adhesive tape of the present invention is not particularly limited, and it is preferably used for assembling an electronic device (such as a mobile phone, a mobile information terminal, etc.) equipped with an image display device or an input device, assembling and fixing automobile parts, and the like. More specifically, for example, it is preferred to adhere low-polarity adherends such as polypropylene (PP) resins used in automobile parts, electrical and electronic equipment parts, and cycloolefin polymer resins used in display modules. .

According to the present invention, it is possible to provide an adhesive tape that is difficult to peel even with a thin adhesive tape and exhibits high fixed-load peelability to a low-polar adherend such as a polypropylene (PP) board.

1‧‧‧ Living radical polymerized acrylic polymer

2‧‧‧ Free Radical Polymerization Acrylic Polymer

11‧‧‧ monomers without hydroxyl and carboxyl groups

12‧‧‧Hydroxy and / or carboxyl-containing monomer

21‧‧‧ monomers without hydroxyl and carboxyl groups

22‧‧‧ Monomers containing hydroxyl and / or carboxyl groups

23‧‧‧Growth end free polymer based on inactivation halfway through the reaction

24‧‧‧ A polymer that grows using newly generated free radical species in the reaction

Figure 1 is a schematic diagram illustrating living radical polymerization.

Figure 2 is a schematic diagram illustrating free radical polymerization.

Hereinafter, the present invention will be described in more detail with the disclosed examples, but the present invention is not limited to these examples.

(Radical Polymerization Polymer)

(Synthesis 1)

(Synthesis 1-1)

Tellurium (40 mesh, metal tellurium, manufactured by Aldrich) 6.38 g (50 mmol) was suspended in 50 mL of tetrahydrofuran (THF), and 1.6 mol / L n-butyllithium / hexane was slowly added dropwise thereto at room temperature. An alkane solution (manufactured by Aldrich) was 34.4 mL (55 mmol). The reaction solution was stirred until the metal tellurium completely disappeared. 10.7 g (55 mmol) of ethyl 2-bromoisobutyrate was added to the reaction solution at room temperature, and stirred for 2 hours. After the reaction was completed, the solvent was concentrated under reduced pressure, followed by distillation under reduced pressure to obtain 2-methyl-2-n-butylhydrotelluride-propionic acid ethyl ester as a yellow oil.

(Synthesis 1-2)

In a glove box replaced with argon, 38 μL of 2-methyl-2-n-butylhydrotelluride-ethyl propionate produced in Synthesis 1-1, V-60 (2,2'-azo Bisisobutyronitrile (manufactured by Wako Pure Chemical Industries, Ltd.) 2.8 mg and 1 mL of ethyl acetate were put into the reaction container, the reaction container was sealed, and the reaction container was taken out of the glove box. Next, while introducing argon gas into the reaction vessel, a total of 100 g of monomers (BA: butyl acrylate, Aac: acrylic acid, HEA: 2-hydroxyethyl acrylate) shown in Table 1 were used as a polymerization solvent of acetic acid. 66.5 g of ethyl ester was put into a reaction container, and a polymerization reaction was performed at 60 ° C. for 20 hours to obtain a solution containing a living radical polymerized acrylic polymer.

A filter (material: polytetrafluoroethylene, pore size: 0.2 μm) was used for the diluted solution obtained by diluting the obtained living radical polymerized acrylic polymer 50 times with tetrahydrofuran (THF). Filtration was performed, and the obtained filtrate was supplied to a gel permeation chromatography (manufactured by Waters, 2690 Separations Model). GPC measurement was performed under conditions of a sample flow rate of 1 ml / min and a column temperature of 40 ° C. The polystyrene conversion molecular weight was measured, and the weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) were calculated. The column system used GPC KF-806L (manufactured by Showa Denko), and the detector used a differential refractometer.

(Synthesis 2)

The 2-methyl-2-n-butylhydrotelluryl-propionate ethyl ester produced in Synthesis 1-1 was changed to 58 μL, and V-60 (2,2'-azobisisobutyronitrile, Wako Pure Chemical Industries, Ltd. (Manufactured by Pharmaceutical Co., Ltd.) except that the solution was changed to 4.2 mg, and a solution containing a living radical polymerized acrylic polymer was obtained in the same manner as in Synthesis 1-2, and the weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) .

(Synthesis 3)

The 2-methyl-2-n-butylhydrotelluryl-propionate ethyl ester produced in Synthesis 1-1 was changed to 17 μL, and V-60 (2,2'-azobisisobutyronitrile, Wako Pure Chemical Industries, Ltd. (Manufactured by Pharmaceutical Industry Co., Ltd.) except that the solution was changed to 1.2 mg, and a solution containing a living radical polymerized acrylic polymer was obtained in the same manner as in Synthesis 1-2, and the weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) were obtained .

(Synthesis 4)

The 2-methyl-2-n-butylhydrotelluryl-propionate ethyl ester produced in Synthesis 1-1 was changed to 230 μL, and V-60 (2,2'-azobisisobutyronitrile, Wako Pure Chemical Industries, Ltd. Except for changing it to 17 mg, a solution containing a living radical polymerized acrylic polymer was obtained in the same manner as in Synthesis 1-2, and a weight average molecular weight (Mw) and a molecular weight distribution (Mw / Mn) were obtained.

(Synthesis 5)

50 g of ethyl acetate was added to the reaction vessel as a polymerization solvent, and after introducing nitrogen gas, the reaction vessel was heated while introducing nitrogen gas, and reflux was started. Next, a polymerization initiator solution prepared by diluting 0.15 g of V-60 (2,2'-azobisisobutyronitrile, manufactured by Wako Pure Chemical Industries, Ltd.) as a polymerization initiator 10 times with ethyl acetate was used. Put into the reaction container and drip over 2 hours Add a total of 100 g of the monomers shown in Table 1. After the dropwise addition, 0.15 g of V-60 (2,2'-azobisisobutyronitrile, manufactured by Wako Pure Chemical Industries, Ltd.) as a polymerization initiator was polymerized by diluting 10 times with ethyl acetate. The initiator solution was put into the reaction container again, and the polymerization reaction was performed for 4 hours to obtain a solution containing a free radical polymer.

(Adhesion imparting resin)

The adhesion-imparting resin shown in Table 2 was used.

(Examples 1 to 11, Comparative Examples 1 to 10)

With respect to the solution containing the radical polymer obtained as described above, A specific amount of the adhesion-imparting resin shown in Table 3 was added in 100 parts by weight, ethyl acetate was added and stirred, and then a specific amount of a cross-linking agent shown in Tables 3 and 4 was added, and the adhesion-imparting resin was added and stirred to obtain 30% by weight non-volatile adhesive solution. After the obtained adhesive solution was applied to a PET film having a thickness of 50 μm so as to have a tape thickness as shown in Table 3 after being dried, it was dried at 70 ° C. for 10 minutes to obtain an adhesive tape. Furthermore, the surface area layers on both sides of the adhesive layer are used to protect the release film of the adhesive layer.

The obtained adhesive tape was cut into a flat rectangular shape of 50 mm × 100 mm to prepare a test piece, and the release film was removed by peeling. After the test piece was immersed in ethyl acetate at 23 ° C for 24 hours, it was taken out from the ethyl acetate and dried at 110 ° C for 1 hour. The weight of the dried test piece was measured, and the gel fraction was calculated using the following formula (1).

Gel fraction (wt%) = 100 × (W2-W0) / (W1-W0) (1)

(W0: weight of substrate, W1: weight of test piece before immersion, W2: weight of test piece after immersion and drying)

(Evaluation)

The adhesive tape obtained in the Example and the comparative example was evaluated as follows. The results are shown in Tables 3 and 4.

(1) Fixed load peelability to polypropylene (PP) board

The adhesive tape with a width of 20 mm × 50 mm was affixed to a polypropylene (PP) board, and after curing overnight at 23 ° C and 50% humidity, a load of 50 g was applied to the direction of 90 ° at 60 ° C, and 30 was measured. Peel distance after minutes.

◎: Peeling distance is 5mm or less

○: Peeling distance exceeds 5 mm and is 10 mm or less

△: Peeling distance exceeds 10mm and 15mm or less

×: Peeling distance exceeds 15mm

[Industrial availability]

According to the present invention, it is possible to provide an adhesive tape that is difficult to peel even with a thin adhesive tape and exhibits a high fixed-load peeling property to a low-polar adherend such as a polypropylene (PP) board.

Claims (5)

An adhesive tape having an adhesive layer containing: a polymer component containing 60% by weight or more of a weight average molecular weight obtained by living radical polymerization (Living Radical Polymerization) of 300,000 to 2 million And an acrylic polymer containing a hydroxyl group and / or a carboxyl group having a molecular weight distribution (Mw / Mn) of 1.05 to 2.5; a rosin-based adhesion imparting resin having a hydroxyl group and / or a carboxyl group and a terpene-based adhesion imparting agent having a hydroxyl group and / or a carboxyl group Resin; and cross-linking agent. For example, the softening temperature of rosin-based adhesion-imparting resin or terpene-based adhesion-imparting resin is 70-170 ° C. For example, the adhesive tape of the scope of patent application No. 1 or 2, in which the rosin-based adhesion-imparting resin or terpene-based adhesion-imparting resin has a hydroxyl value of 25 to 55. For example, the adhesive tape of the first or second patent application range, wherein the acrylic polymer is obtained by living radical polymerization of an acrylic monomer containing (meth) acrylic acid in an amount of 0.1% by weight to 10% by weight. For example, the adhesive tape of item 1 or 2 of the patent application scope, wherein the gel fraction of the adhesive layer is 70% by weight or less.