WO2017110839A1 - Adhesive composition and adhesive tape - Google Patents

Abstract

The purpose of the invention is to provide an adhesive composition that makes it possible to obtain an adhesive tape having excellent repulsion resistance as well as excellent handleability, and an adhesive tape obtained using the adhesive composition. The invention is an adhesive composition containing a polymer component containing an acrylic polymer having crosslinkable functional groups, a tackifying resin in which the hydroxyl value of the alcoholic hydroxyl groups is 70 mg KOH/g or higher, and a crosslinking agent.

Description

Adhesive composition and adhesive tape

The present invention relates to a pressure-sensitive adhesive composition capable of obtaining a pressure-sensitive adhesive tape having excellent resilience and handling properties, and a pressure-sensitive adhesive tape using the pressure-sensitive adhesive composition.

An adhesive tape having an adhesive layer made of an adhesive composition is used in various industrial fields because it can be simply joined. In the electric and electronic field, for example, adhesive tapes are used for assembling modules and attaching modules to a housing in electronic devices such as personal computers, mobile phones, smartphones, and tablets. More specifically, for example, a double-sided pressure-sensitive adhesive tape is used for assembly in a portable electronic device (for example, a mobile phone, a portable information terminal, etc.) equipped with an image display device or an input device. For example, a double-sided adhesive tape is used to bond a cover panel for protecting the surface of a portable electronic device to a touch panel module or a display panel module, or to bond a touch panel module and a display panel module. Such a double-sided pressure-sensitive adhesive tape is used, for example, by being punched into a frame shape or the like and arranged around the display screen (for example, Patent Documents 1 and 2). Moreover, the double-sided adhesive tape which has an adhesive layer which consists of an adhesive composition is also used for the use which fixes vehicle components (for example, vehicle-mounted panel) to a vehicle main body.

In applications such as adhesive bonding of parts and adhesion fixing of vehicle parts in large-sized portable electronic devices in recent years, according to increasing needs for miniaturization, thinning or weight reduction of parts, or resource saving, Thin adhesive tapes are desired. However, there is a problem that a thin adhesive tape cannot provide a sufficient adhesive force and is inferior in repulsion resistance that maintains high adhesion reliability against deformation such as warping of a fixed part.
Also, in recent portable electronic devices, so-called narrower frames, in which the periphery of the display screen is narrowed to ensure a wider screen, are progressing, and the width of the peripheral portion of the screen is extremely narrow in narrowed portable electronic devices. Therefore, there is a demand for an adhesive tape having a narrower line width (a smaller bonding area) than in the past. However, when it is attempted to punch into such a narrow line width, there is a problem in handling property that adhesive remains on the punching blade and the punch cannot be punched efficiently and accurately.

JP 2009-242541 A JP 2009-258274 A

An object of this invention is to provide the adhesive composition which can obtain the adhesive tape which is excellent in resilience resistance, and is excellent also in handleability, and the adhesive tape using this adhesive composition.

The present invention is a pressure-sensitive adhesive composition containing a polymer component containing an acrylic polymer having a crosslinkable functional group, a tackifying resin having a hydroxyl value of an alcoholic hydroxyl group of 70 mgKOH / g or more, and a crosslinking agent. .
The present invention is described in detail below.

As a result of intensive studies, the inventors of the present invention contain a polymer component containing an acrylic polymer having a crosslinkable functional group, a tackifying resin having a hydroxyl value of an alcoholic hydroxyl group of 70 mgKOH / g or more, and a crosslinking agent. The present inventors have found that a pressure-sensitive adhesive composition having excellent resilience and handling properties can be obtained by using the pressure-sensitive adhesive composition.
A pressure-sensitive adhesive composition comprising a polymer component containing an acrylic polymer having a crosslinkable functional group, a tackifier resin having an alcoholic hydroxyl group (hereinafter also simply referred to as “tackifier resin”), and a crosslinker. When the pressure-sensitive adhesive tape is produced by using, the polymer layer or the polymer chain and the tackifying resin are cross-linked in the pressure-sensitive adhesive layer. At this time, by using “tackifying resin having a hydroxyl value of alcoholic hydroxyl group of 70 mgKOH / g or more” as the tackifying resin, it is highly cross-linked and exhibits higher resilience and is punched into a narrow line width. Even when trying to do so, it is considered that no adhesive residue is left on the punching blade, so that it can be punched efficiently and accurately.
In the present specification, an alcoholic hydroxyl group means a hydroxyl group bonded to a carbon atom having an sp ³ hybrid orbital that can participate in a crosslinking reaction, and is clearly distinguished from a phenolic hydroxyl group.

The pressure-sensitive adhesive composition of the present invention contains a polymer component containing an acrylic polymer having a crosslinkable functional group. By using an acrylic polymer having a crosslinkable functional group, when a crosslinking agent is used in combination, the polymer chains or between the polymer chain and the tackifier resin are crosslinked, and repulsion resistance can be exhibited.

The acrylic polymer having a crosslinkable functional group can be obtained by polymerizing a monomer mixture containing an acrylic monomer having a crosslinkable functional group.
Examples of the crosslinkable functional group include a hydroxyl group, a carboxyl group, a glycidyl group, an amino group, an amide group, and a nitrile group. Especially, since adjustment of the gel fraction of the said adhesive layer is easy, a hydroxyl group or a carboxyl group is preferable and a hydroxyl group is more preferable.

Examples of the 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.
As a monomer which has a carboxyl group, (meth) acrylic acid is mentioned, for example.
Examples of the monomer having a glycidyl group include glycidyl (meth) acrylate.
Examples of the monomer having an amide group include hydroxyethyl acrylamide, isopropyl acrylamide, dimethylaminopropyl acrylamide and the like.
Examples of the monomer having a nitrile group include acrylonitrile.

In the acrylic polymer having a crosslinkable functional group, the preferable lower limit of the content of the component derived from the acrylic monomer having a crosslinkable functional group is 0.01% by weight, and the preferable upper limit is 20% by weight. By setting the content of the structural component derived from the acrylic monomer having a crosslinkable functional group within this range, higher resilience resistance is exhibited and also when trying to punch into a narrow line width. It is difficult to leave glue on the punching blade, and it can be punched efficiently and accurately. The more preferable lower limit of the content of the component derived from the acrylic monomer having the crosslinkable functional group is 0.05% by weight, and the more preferable upper limit is 10% by weight.

The monomer mixture may use a radical polymerizable monomer other than the acrylic monomer having a crosslinkable functional group. As said other radically polymerizable monomer, other (meth) acrylic acid ester is mentioned, for example. In addition, acrylic monomers having other polar functional groups such as amino groups, amide groups, and nitrile groups can also be used. Furthermore, in addition to the acrylic monomer, a vinyl compound may be used as a monomer.

The other (meth) acrylic acid esters are not particularly limited, and are methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, tert-butyl (meth) acrylate, 2 (Meth) acrylic acid alkyl esters such as ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate, isomyristyl (meth) acrylate, stearyl (meth) acrylate, Cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, benzyl (meth) acrylate, 2-butoxyethyl (meth) acrylate, 2-phenoxyethyl (meth) acrylate, glycidyl (meth) acrylate , Tetrahydrofurfuryl (meth) acrylate, polypropylene glycol mono (meth) acrylate. These (meth) acrylic acid esters may be used alone or in combination of two or more.

The vinyl compound is not particularly limited, and examples thereof include (meth) acrylamide compounds such as N, N-dimethylacrylamide, N, N-diethylacrylamide, N-isopropylacrylamide, N-hydroxyethylacrylamide, and acrylamide, N-vinylpyrrolidone, N-vinylcaprolactam, N-vinylacetamide, N-acryloylmorpholine, acrylonitrile, styrene, vinyl acetate and the like can be mentioned. These vinyl compounds may be used alone or in combination of two or more.

The acrylic polymer having a crosslinkable functional group is preferably an acrylic polymer obtained by living radical polymerization (hereinafter also referred to as “living radical polymerization acrylic polymer”).
Living radical polymerization is polymerization in which molecular chains grow without the polymerization reaction being hindered by side reactions such as termination reactions or chain transfer reactions. According to living radical polymerization, for example, a polymer having a more uniform molecular weight and composition than that of free radical polymerization can be obtained, and the generation of low molecular weight components and the like can be suppressed. Sometimes it is possible to obtain an adhesive tape that is less likely to have adhesive residue.

FIG. 1 shows a schematic diagram for explaining living radical polymerization. Living radical polymerization is polymerization in which molecular chains grow without the polymerization reaction being hindered by side reactions such as termination reactions or chain transfer reactions. In living radical polymerization, the reaction proceeds without the growth terminal radicals being deactivated and without generating new radical species during the reaction. In the middle of the reaction, all polymer chains are polymerized while uniformly reacting with the monomer, and the composition of all polymers approaches uniform. Therefore, the crosslinkable functional group-containing monomer 112 is included in all the polymers of the acrylic polymer 11 to be obtained. If the acrylic polymer 11 obtained by such living radical polymerization is combined with a tackifier resin and a cross-linking agent, almost all polymers can crosslink between polymer chains or crosslink between a polymer chain and a tackifier resin. Can be involved. FIG. 2 shows a schematic diagram for explaining a case where an acrylic polymer obtained by living radical polymerization is crosslinked. In the acrylic polymer obtained by living radical polymerization, the composition of all polymers is uniform, and since the crosslinkable functional group-containing monomer is included, all polymer chains are involved in crosslinking. In FIG. 2, a hydroxyl group is shown as an example of the crosslinkable functional group.
As described above, since almost all polymers can participate in the crosslinking between polymer chains, it is possible to obtain a pressure-sensitive adhesive tape that has particularly high repulsion resistance and is less likely to remain glue when stamped.

Such an effect cannot be obtained even by using an acrylic polymer obtained by conventional free radical polymerization (hereinafter also referred to as “free radical polymerization acrylic polymer”).
FIG. 3 is a schematic diagram for explaining free radical polymerization. In free radical polymerization, radical species are continuously generated during the reaction and added to the monomer, and the polymerization proceeds. Therefore, in the free radical polymerization, a polymer 123 in which the growing terminal radical is deactivated during the reaction and a polymer 124 grown by the radical species newly generated during the reaction are generated. Therefore, when an acrylic polymer containing a crosslinkable functional group is produced by free radical polymerization, a polymer containing no relatively low molecular weight crosslinkable functional group-containing monomer is produced. Even when the acrylic polymer 12 obtained by such free radical polymerization is crosslinked using a crosslinking agent, a polymer that does not contain a crosslinkable functional group-containing monomer cannot participate in crosslinking between polymer chains. . FIG. 4 is a schematic diagram for explaining a case where an acrylic polymer obtained by free radical polymerization is crosslinked. The acrylic polymer obtained by free radical polymerization has a non-uniform polymer composition and contains a polymer that does not contain a relatively low molecular weight crosslinkable functional group-containing monomer. ing. In FIG. 4, a hydroxyl group is shown as an example of the crosslinkable functional group. When pasted on an adherend as a double-sided adhesive tape, the part that does not contain a crosslinkable functional group-containing monomer that cannot participate in crosslinking is easy to peel off. The adhesiveness is liable to decrease, and the adhesive remains easily at the time of punching.

As described above, the living radical polymerization acrylic polymer has a more uniform molecular weight and composition as compared with free radical polymerization and the like, has a low content of low molecular weight components, and almost all polymers have a crosslinkable functional group-containing monomer. It has the property of being included. The effect of the present invention that it is possible to achieve both high adhesive strength and releasability that can be peeled without adhesive residue is particularly excellent when a living radical polymerization acrylic polymer is used.
The characteristics of such a living radical polymerization acrylic polymer are due to a production method called living radical polymerization in which a molecular chain grows without being hindered by a side reaction such as a termination reaction or a chain transfer reaction. However, although it is possible to indirectly represent the characteristics of the living radical polymerization acrylic polymer as an average value of the whole polymer such as weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn), It is extremely difficult to directly specify the structure and properties of the chain length and the monomer component in each polymer. It must be said that it is impossible or not practical to directly identify the living radical polymerized acrylic polymer by its structure or properties. Therefore, in the present invention, it should be allowed to describe the living radical polymerization acrylic polymer by the “acrylic polymer obtained by living radical polymerization” and the production method thereof.

Among living radical polymerizations, living radical polymerization using an organic tellurium polymerization initiator protects all radical polymerizable monomers having polar functional groups such as hydroxyl groups and carboxyl groups, unlike other living radical polymerizations. Without polymerization, the same initiator can be polymerized to obtain a polymer having a uniform molecular weight and composition. For this reason, the radically 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 compounds include (methylterranyl-methyl) benzene, (1-methylterranyl-ethyl) benzene, (2-methylterranyl-propyl) benzene, 1-chloro-4- (methylterranyl-methyl) benzene, 1-hydroxy- 4- (methylterranyl-methyl) benzene, 1-methoxy-4- (methylterranyl-methyl) benzene, 1-amino-4- (methylterranyl-methyl) benzene, 1-nitro-4- (methylterranyl-methyl) benzene, 1- Cyano-4- (methylterranyl-methyl) benzene, 1-methylcarbonyl-4- (methylterranyl-methyl) benzene, 1-phenylcarbonyl-4- (methylterranyl-methyl) benzene, 1-methoxycarbonyl-4- (methylterranyl-methyl) ) Benzene, 1- Enoxycarbonyl-4- (methylterranyl-methyl) benzene, 1-sulfonyl-4- (methylterranyl-methyl) benzene, 1-trifluoromethyl-4- (methylterranyl-methyl) benzene, 1-chloro-4- (1 -Methylterranyl-ethyl) benzene, 1-hydroxy-4- (1-methylterranyl-ethyl) benzene, 1-methoxy-4- (1-methylterranyl-ethyl) benzene, 1-amino-4- (1-methylterranyl-ethyl) Benzene, 1-nitro-4- (1-methylterranyl-ethyl) benzene, 1-cyano-4- (1-methylterranyl-ethyl) benzene, 1-methylcarbonyl-4- (1-methylterranyl-ethyl) benzene, 1- Phenylcarbonyl-4- (1-methylterranyl-ethyl) benzene, 1-meth Sicarbonyl-4- (1-methylterranyl-ethyl) benzene, 1-phenoxycarbonyl-4- (1-methylterranyl-ethyl) benzene, 1-sulfonyl-4- (1-methylterranyl-ethyl) benzene, 1-trifluoromethyl -4- (1-methylterranyl-ethyl) benzene, 1-chloro-4- (2-methylterranyl-propyl) benzene, 1-hydroxy-4- (2-methylterranyl-propyl) benzene, 1-methoxy-4- (2 -Methylterranyl-propyl) benzene, 1-amino-4- (2-methylterranyl-propyl) benzene, 1-nitro-4- (2-methylterranyl-propyl) benzene, 1-cyano-4- (2-methylterranyl-propyl) Benzene, 1-methylcarbonyl-4- (2-methylterranyl-propyl ) Benzene, 1-phenylcarbonyl-4- (2-methylterranyl-propyl) benzene, 1-methoxycarbonyl-4- (2-methylterranyl-propyl) benzene, 1-phenoxycarbonyl-4- (2-methylterranyl-propyl) benzene 1-sulfonyl-4- (2-methylterranyl-propyl) benzene, 1-trifluoromethyl-4- (2-methylterranyl-propyl) benzene, 2- (methylterranyl-methyl) pyridine, 2- (1-methylterranyl-ethyl) ) Pyridine, 2- (2-methyl teranyl-propyl) pyridine, 2-methyl teranyl-methyl ethanoate, 2-methyl teranyl-methyl propionate, 2-methyl teranyl-2-methyl propionate, 2-methyl teranyl-ethyl ethanoate, 2 -Methylterranil Ethyl propionate, 2-Mechiruteraniru -2-methylpropionic acid ethyl, 2-methyl-Terra alkylsulfonyl acetonitrile, 2-methyl-Terra sulfonyl propionitrile, 2-methyl-2-methyl-Terra sulfonyl propionitrile, and the like. The methyl terranyl group in these organic tellurium compounds may be an ethyl terranyl group, n-propyl terranyl group, isopropyl terranyl group, n-butyl terranyl group, isobutyl terranyl group, t-butyl terranyl group, phenyl terranyl group, 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, dicyclopropyl ditelluride, di-n-butyl ditelluride, di-sec-butyl ditelluride. , Di-tert-butylditelluride, dicyclobutylditelluride, diphenylditelluride, bis- (p-methoxyphenyl) ditelluride, bis- (p-aminophenyl) ditelluride, bis- (p-nitrophenyl) ditelluride, bis -(P-cyanophenyl) ditelluride, bis- (p-sulfonylphenyl) ditelluride, dinaphthyl ditelluride, dipyridyl ditelluride and the like. These organic telluride compounds may be used alone or in combination of two or more. Of these, dimethyl ditelluride, diethyl ditelluride, di-n-propyl ditelluride, di-n-butyl ditelluride and diphenyl ditelluride are preferable.

In addition, within the range which does not impair the effect of this invention, in addition to the said organic tellurium polymerization initiator, you may use an azo compound as a polymerization initiator for the purpose of acceleration | stimulation of a polymerization rate.
The azo compound is not particularly limited as long as it is generally used for radical polymerization. For example, 2,2′-azobis (isobutyronitrile), 2,2′-azobis (2-methylbutyronitrile) is used. ), 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] formamide, 4,4′-azobis (4-cyanovaleric acid), dimethyl-2,2′-azobis (2-methylpropionate), Dimethyl-1,1′-azobis (1-cyclohexanecarboxylate), 2,2′-azobis {2-methyl-N- [1,1′-bis (hydroxymethyl) -2-hydroxyethyl Propionamide}, 2,2′-azobis [2-methyl-N- (2-hydroxyethyl) propionamide], 2,2′-azobis [N- (2-propenyl) -2-methylpropionamide], 2 , 2′-azobis (N-butyl-2-methylpropionamide), 2,2′-azobis (N-cyclohexyl-2-methylpropionamide), 2,2′-azobis [2- (2-imidazoline-2 -Yl) propane] dihydrochloride, 2,2'-azobis {2- [1- (2-hydroxyethyl) -2-imidazolin-2-yl] propane} dihydrochloride, 2,2'-azobis [2 -(2-imidazolin-2-yl) propane], 2,2'-azobis (2-amidinopropane) dihydrochloride, 2,2'-azobis [N- (2-carboxyethyl) -2-methylpropionami Tetrahydrate, 2,2′-azobis (1-imino-1-pyrrolidino-2-methylpropane) dihydrochloride, 2,2′-azobis (2,4,4-trimethylpentane), etc. It is done. These azo compounds may be used alone or in combination of two or more.

In the living radical polymerization, a dispersion stabilizer may be used. Examples of the dispersion stabilizer include polyvinyl pyrrolidone, polyvinyl alcohol, methyl cellulose, ethyl cellulose, poly (meth) acrylic acid, poly (meth) acrylic acid ester, and polyethylene glycol.
As the living radical polymerization method, conventionally known methods are used, and examples thereof include solution polymerization (boiling point polymerization or constant temperature polymerization), emulsion polymerization, suspension polymerization, bulk polymerization and the like.
When a polymerization solvent is used in the living radical polymerization, the polymerization solvent is not particularly limited. For example, a nonpolar solvent such as hexane, cyclohexane, octane, toluene, xylene, water, methanol, ethanol, propanol, butanol, acetone, Highly polar solvents such as methyl ethyl ketone, methyl isobutyl ketone, tetrahydrofuran, dioxane, N, N-dimethylformamide can be used. These polymerization solvents may be used alone or in combination of two or more.
The polymerization temperature is preferably 0 to 110 ° C. from the viewpoint of the polymerization rate.

The acrylic polymer having the crosslinkable functional group has a preferred lower limit of 300,000 and a preferred upper limit of 2,000,000 for the weight average molecular weight (Mw). By setting the weight average molecular weight within this range, higher resilience resistance can be exhibited.

The acrylic polymer having the crosslinkable functional group has a preferred lower limit of 1.05 and a preferred upper limit of 2.5 for the molecular weight distribution (Mw / Mn). By setting the molecular weight distribution within this range, higher resilience can be exhibited. A more preferable upper limit of the molecular weight distribution is 2.0, and a further preferable upper limit is 1.8.
The molecular weight distribution (Mw / Mn) is a ratio between the weight average molecular weight (Mw) and the number average molecular weight (Mn).

The said weight average molecular weight (Mw) and number average molecular weight (Mn) are measured as a polystyrene conversion molecular weight by the gel permeation chromatography (GPC) method. Specifically, the weight average molecular weight (Mw) and the number average molecular weight (Mn) are obtained by filtering a diluted solution obtained by diluting an acrylic polymer having a crosslinkable functional group 50 times with tetrahydrofuran (THF) through a filter. Using the obtained filtrate, it is measured as a polystyrene-equivalent molecular weight by the 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 acrylic polymer having the crosslinkable functional group.
However, the preferable lower limit of the content of the acrylic polymer having the crosslinkable functional group in the polymer component is 60% by weight, and the total amount (100% by weight) of the polymer component has the crosslinkable functional group. It is preferable that By setting the content of the acrylic polymer having the crosslinkable functional group in the polymer component to 60% by weight or more, a higher heat-sensitive adhesive force can be exhibited.
The tackifying resin is not included in the polymer component.

The pressure-sensitive adhesive composition of the present invention contains a tackifier resin having a hydroxyl value of an alcoholic hydroxyl group of 70 mgKOH / g or more. By using a tackifier resin having an alcoholic hydroxyl group and a crosslinking agent in combination with the acrylic polymer having the crosslinkable functional group, the polymer chain and the tackifier resin are crosslinked. For example, when the acrylic polymer having a crosslinkable functional group has a hydroxyl group, a tackifier resin having an acrylic polymer having the crosslinkable functional group and an alcoholic hydroxyl group is obtained by using, for example, an isocyanate crosslinker as a crosslinker. Both of them react and crosslink via a crosslinking agent. By using a tackifier resin having a hydroxyl value of an alcoholic hydroxyl group of 70 mgKOH / g or more, it is highly cross-linked, exhibits higher resilience resistance, and is also punched when trying to punch into a narrow line width. It is difficult for glue to remain on the blade, and it can be punched efficiently and accurately. The hydroxyl value of the alcoholic hydroxyl group of the tackifying resin is preferably 85 mgKOH / g or more, and more preferably 100 mgKOH / g or more.
In particular, when the acrylic polymer having a crosslinkable functional group is a living radical polymerization acrylic polymer, the composition of almost all the polymers contained is uniform and the crosslinkable functional group is present, so almost all the polymers are polymers. It can participate in cross-linking between chains and cross-linking between polymer chains and tackifying resins.
The hydroxyl value of the alcoholic hydroxyl group can be measured by JIS K1557 (phthalic anhydride method).

The tackifier resin preferably has 1.6 or more alcoholic hydroxyl groups contained in one molecule. As a result, the adhesive force (heat-sensitive adhesive force) when bonding is performed while applying a temperature of about 80 ° C. can be drastically improved. On the other hand, it is possible to exert an excellent effect that the adhesive can be peeled without any adhesive residue. . The number of alcoholic hydroxyl groups contained in one molecule is more preferably 1.7 or more, and still more preferably 1.8 or more.
In comparison with a tackifier resin having less than 1.6 alcoholic hydroxyl groups contained in one molecule, the tackifier resin having a chemical structure of “1.6 or more alcoholic hydroxyl groups contained in one molecule” Since the steric hindrance around the alcoholic hydroxyl group is reduced, the reactivity between the tackifying resins or between the tackifying resin and the acrylic polymer having a crosslinkable functional group is increased, and the bulk strength of the adhesive layer is improved. We believe that heat sensitivity improves the flowability of the pressure-sensitive adhesive composition and improves the adhesion to the adherend, dramatically improving the heat-sensitive adhesive force and preventing adhesive residue at the time of peeling. It is done.
For example, in the step of polishing a semiconductor wafer to a predetermined thickness, polishing is performed using an abrasive fixed to a surface plate of a polishing machine. In order to fix the abrasive to the surface plate of the polishing machine, a double-sided adhesive tape is usually used. This double-sided pressure-sensitive adhesive tape for fixing abrasives is required to have sufficient adhesive strength so that the abrasive does not peel during polishing, and when the used abrasive is replaced, it can be peeled off from the surface plate without any adhesive residue. I came. Similar applications include fixing an abrasive on a liquid crystal glass substrate, fixing a CMP (Chemical Mechanical Planarization), and fixing a rubbing cloth. If the number of alcoholic hydroxyl groups contained in one molecule of the tackifying resin is 1.6 or more and the heat-sensitive adhesive force to a base material such as polypropylene can exceed 20 N / 25 mm, the adhesive is used for fixing abrasives. Even if a large stress is applied to the tape, it is possible to reliably prevent the abrasive from peeling off during polishing.
The upper limit of the alcoholic hydroxyl group contained in one molecule is not particularly limited, but is 3 or less from the viewpoint of reactivity with the acrylic polymer having a crosslinkable functional group and a crosslinking agent, and a chemical structure. Is preferred.

In addition, the number of alcoholic hydroxyl groups contained in one molecule of the tackifier resin is measured as follows, for example.
First, the diluted solution obtained by diluting the tackifying resin 50 times with tetrahydrofuran (THF) is filtered through a filter (for example, a filter made of polytetrafluoroethylene having a pore diameter of 0.2 μm), and the obtained filtrate is obtained. Is supplied to a gel permeation chromatograph (GPC, for example, 2690 Separations Model, manufactured by Waters), GPC measurement is performed under the conditions of a sample flow rate of 1 mL / min and a column temperature of 40 ° C., and the molecular weight in terms of polystyrene is measured. Determine the average molecular weight. Furthermore, the hydroxyl value is measured by JIS K1557 (phthalic anhydride method), and the number of alcoholic hydroxyl groups contained in one molecule of the tackifier resin is calculated using the following formula (1).
Number of hydroxyl groups = (Mn × OHV) / 56110 (1)
(Mn: number average molecular weight of tackifying resin, OHV: hydroxyl value of alcoholic hydroxyl group of tackifying resin (mgKOH / g))

The tackifier resin is not particularly limited, but rosin ester resin and hydrogenated terpene phenol resin are preferable.
The rosin ester-based resin is a rosin resin mainly composed of abietic acid, a disproportionated rosin resin, a hydrogenated rosin resin, a dimer of a resin acid such as abietic acid (polymerized rosin resin), or the like. It is a resin obtained by esterification. A part of hydroxyl groups of alcohols used for esterification are contained in the resin without being used for esterification, whereby the hydroxyl value is adjusted to the above range.
Esterified rosin resin is rosin ester resin, disproportionated rosin resin is esterified disproportionated rosin ester resin, hydrogenated rosin resin is esterified hydrogenated rosin ester resin, polymerized rosin resin The esterified product is a polymerized rosin ester resin. Examples of the alcohols used for the esterification include polyhydric alcohols such as ethylene glycol, glycerin, and pentaerythritol.
The hydrogenated terpene phenolic resin is a terpene phenolic resin obtained by polymerizing terpene in the presence of phenol. Resin.
These tackifier resins may be used alone or in combination of two or more.

The method for controlling the hydroxyl value of the alcoholic hydroxyl group of the tackifier resin and the number of alcoholic hydroxyl groups contained in one molecule is not particularly limited. For example, when the tackifier resin is a rosin ester resin, This can be controlled by adjusting the degree of esterification reaction between the rosin resin acid and the alcohol. Specifically, for example, by using a polyhydric alcohol as the alcohol and reducing the degree of esterification, it is possible to obtain a rosin ester resin having a high hydroxyl group and a large amount of alcoholic hydroxyl groups in the molecule. For example, when the tackifier resin is a hydrogenated terpene phenol resin, it can be controlled by adjusting the phenol copolymerization amount of the terpene phenol resin as a raw material and the degree of hydrogenation. Specifically, for example, by increasing the degree of hydrogenation by increasing the amount of phenol copolymerization of the terpene phenol-based resin or increasing the molecular weight of the terpene phenol-based resin, A hydrogenated terpene phenol resin having a large amount of alcoholic hydroxyl group can be obtained.

The tackifying resin has a preferred softening temperature lower limit of 100 ° C. and a preferred upper limit of 180 ° C. When the softening temperature is within this range, particularly excellent resilience can be exhibited.
The softening temperature is a softening temperature measured by the JIS K2207 ring and ball method.

The content of the tackifier resin is preferably 5 parts by weight with respect to 100 parts by weight of the acrylic polymer having a crosslinkable functional group, and 50 parts by weight with a preferred upper limit. By setting the content of the tackifying resin having a hydroxyl group within this range, a particularly excellent repulsion resistance can be exhibited, and a pressure-sensitive adhesive layer that can be punched without any adhesive residue at the time of punching. it can. The minimum with more preferable content of the tackifying resin which has the said hydroxyl group is 10 weight part, and a more preferable upper limit is 45 weight part.

The pressure-sensitive adhesive composition of the present invention contains a crosslinking agent.
The said crosslinking agent is not specifically limited, According to the combination of the acrylic polymer which has the said crosslinkable functional group, and the tackifier resin which has a hydroxyl group, the crosslinking agent which can bridge | crosslink these is selected suitably.
Examples of the crosslinking agent include isocyanate crosslinking agents, aziridine crosslinking agents, epoxy crosslinking agents, metal chelate crosslinking agents, and the like. Especially, since it is excellent in the adhesive stability with respect to a base material, an isocyanate type crosslinking agent is preferable.
Examples of the isocyanate-based crosslinking agent include Coronate HX (manufactured by Nippon Polyurethane Industry Co., Ltd.), Coronate L (manufactured by Nippon Polyurethane Industry Co., Ltd.), and Mytec NY260A (manufactured by Mitsubishi Chemical Corporation).

The content of the crosslinking agent is preferably 0.1 parts by weight and preferably 5 parts by weight with respect to 100 parts by weight of the acrylic polymer having a crosslinkable functional group. By setting the content of the cross-linking agent within this range, a particularly excellent repulsion resistance can be exhibited, and a pressure-sensitive adhesive layer that can be punched without any adhesive residue during punching can be obtained. Moreover, the gel fraction of an adhesive layer can be adjusted by adjusting the kind or quantity of the said crosslinking agent suitably.

The pressure-sensitive adhesive composition of the present invention contains other resins such as plasticizers, emulsifiers, softeners, fillers, pigments, dyes, silane coupling agents, antioxidants and other additives as necessary. It may be.

If the pressure-sensitive adhesive composition of the present invention is used, a pressure-sensitive adhesive tape having excellent resilience and handling properties can be obtained.
The pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer made of the pressure-sensitive adhesive composition of the present invention is also one aspect of the present invention.

The pressure-sensitive adhesive tape of the present invention may be a support type having a base material or a non-support type having no base material. In the case of the support type, it may be a single-sided pressure-sensitive adhesive tape in which a pressure-sensitive adhesive layer is formed on one side of the base material, or a double-sided pressure-sensitive adhesive tape in which a pressure-sensitive adhesive layer is formed on both sides of the base material.
When the pressure-sensitive adhesive tape of the present invention is a double-sided pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer formed on both sides of the substrate, the pressure-sensitive adhesive layer on only one surface is a pressure-sensitive adhesive layer comprising the pressure-sensitive adhesive composition of the present invention. The pressure-sensitive adhesive layer on both sides may be a pressure-sensitive adhesive layer made of the pressure-sensitive adhesive composition of the present invention. Especially, since higher resilience resistance is obtained, it is preferable that a double-sided adhesive layer is an adhesive layer which consists of an adhesive composition of this invention.

The pressure-sensitive adhesive layer preferably has a gel fraction of 50% by weight or less. When the gel fraction exceeds 50% by weight, the cross-linking density of the pressure-sensitive adhesive layer becomes too high, and the pressure-sensitive adhesive tape is easily peeled off, and the resilience resistance may be lowered.
The lower limit of the gel fraction of the pressure-sensitive adhesive layer is not particularly limited, but is preferably 1% by weight or more, more preferably 5% by weight or more, and more preferably 20% by weight or more from the viewpoint of heat resistance and the like. More preferably.
The gel fraction is measured as follows. First, a double-sided pressure-sensitive adhesive tape was cut into a flat rectangular shape of 50 mm × 100 mm to prepare a test piece. The test piece was immersed in ethyl acetate at 23 ° C. for 24 hours, then taken out from ethyl acetate, and the condition of 110 ° C. Dry under 1 hour. The weight of the test piece after drying is measured, and the gel fraction is calculated using the following formula. In addition, the release film for protecting an adhesive layer shall not be laminated | stacked on the test piece.
Gel fraction (% by weight) = 100 × (W2-W0) / (W1-W0)
(W0: weight of substrate, W1: weight of test piece before immersion, W2: weight of test piece after immersion and drying)

The thickness of the pressure-sensitive adhesive layer is not particularly limited because it is set depending on the application, but a preferred lower limit is 1 μm and a preferred upper limit is 100 μm. When the thickness is less than 1 μm, the pressure-sensitive adhesive tape is easily peeled off, and high resilience resistance may not be exhibited. When the said thickness exceeds 100 micrometers, a thin adhesive tape may not be obtained. The more preferable lower limit of the thickness is 5 μm, and the more preferable upper limit is 75 μm.

Although the said base material is not specifically limited, A resin film, a resin foam, paper, a nonwoven fabric, a yarn cloth cloth etc. are mentioned.
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-acrylic ester copolymers. Examples thereof include a resin film, a polyvinyl chloride resin film, a polyurethane resin film, and a cycloolefin polymer resin film.
Examples of the resin foam include polyethylene foam, polypropylene foam, acrylic foam, urethane foam, and ethylene propylene rubber foam.
Examples of the yarn cloth cloth include a woven polyethylene flat yarn and a laminate of a resin film on the surface thereof.

The thickness of the substrate is not particularly limited because it is set depending on the use, but for example, in the case of a film substrate, it is preferably 1 to 100 μm, more preferably 5 to 75 μm. When the thickness of the substrate is less than 1 μm, the mechanical strength of the adhesive tape may be lowered. If the thickness of the base material exceeds 100 μm, the adhesive tape may become too stiff and it may be difficult to adhere and adhere together along the shape of the adherend.

The production method of the pressure-sensitive adhesive tape of the present invention is not particularly limited. For example, the acrylic polymer having a crosslinkable functional group, a tackifier resin, and a crosslinking agent are mixed with other components to be blended as necessary, and stirred. Then, the pressure-sensitive adhesive composition is prepared, and subsequently, the pressure-sensitive adhesive composition is coated and dried on a release-treated PET film to form a pressure-sensitive adhesive layer. Examples thereof include a method of transferring to both surfaces and a method of directly coating and drying the substrate. A pressure-sensitive adhesive layer formed by coating and drying a PET film obtained by releasing the pressure-sensitive adhesive solution may be used as a non-support type double-sided pressure-sensitive adhesive tape without a substrate.

Although the use of the adhesive tape of this invention is not specifically limited, For example, it can use especially suitably for fixation of electronic equipment components, and fixation of vehicle-mounted components. Specifically, the pressure-sensitive adhesive tape of the present invention can be used for adhesive fixing of electronic device parts in large-sized portable electronic devices, adhesive fixing of in-vehicle components (for example, in-vehicle panels), and the like.
The double-sided pressure-sensitive adhesive tape for fixing electronic device parts comprising the pressure-sensitive adhesive tape of the present invention is also one aspect of the present invention. The in-vehicle component fixing double-sided pressure-sensitive adhesive tape comprising the pressure-sensitive adhesive tape of the present invention is also one aspect of the present invention.
The shape of the double-sided pressure-sensitive adhesive tape for fixing electronic device parts and the double-sided pressure-sensitive adhesive tape for fixing vehicle-mounted parts of the present invention is not particularly limited, and examples thereof include a rectangular shape, a frame shape, a circular shape, an elliptical shape, and a donut shape.
Since the double-sided pressure-sensitive adhesive tape of the present invention has a high heat-resistant adhesive property, it can be particularly preferably used for fixing electronic device parts and in-vehicle parts even if the line width is 1 mm or less.

The pressure-sensitive adhesive tape of the present invention fixes an abrasive material used for polishing a semiconductor wafer to a predetermined thickness on a surface plate of a polishing machine, fixes an abrasive material on a liquid crystal glass substrate, or CMP (Chemical Mechanical Planarization). It can also be suitably used for applications such as fixing a mechanical polishing pad) and fixing a rubbing cloth.
An abrasive fixing double-sided pressure-sensitive adhesive tape comprising the pressure-sensitive adhesive tape of the present invention is also one aspect of the present invention.

As a manufacturing method of the double-sided pressure-sensitive adhesive tape for fixing an abrasive material of the present invention, for example, first, two release films that are subjected to a release treatment on one surface, and a pressure-sensitive adhesive for a pressure-sensitive adhesive layer for fixing a platen (a solvent ( For example, a solvent (for example, toluene, xylene, an adhesive solution for an adhesive layer for fixing a platen and an adhesive layer for fixing an abrasive material) formed by adding toluene, xylene, ethyl acetate, etc. A pressure-sensitive adhesive liquid for polishing and fixing pressure-sensitive adhesive layer formed by adding ethyl acetate or the like) is prepared. Subsequently, a pressure-sensitive adhesive solution for the platen fixing pressure-sensitive adhesive layer was applied to the release-treated surface of one release film, and the solvent in the pressure-sensitive adhesive solution was completely dried and removed to remove the release film. A platen-fixing pressure-sensitive adhesive layer laminated film in which a platen-fixing pressure-sensitive adhesive layer is formed on the release treatment surface is prepared. On the other hand, the adhesive solution for the adhesive layer for fixing the abrasive is applied to the release treatment surface of the other release film, and the solvent in the adhesive solution is completely dried and removed to remove the release film. An abrasive fixing pressure-sensitive adhesive layer laminated film in which an abrasive fixing pressure-sensitive adhesive layer is formed on the treated surface is prepared.
After that, a base film to be a base layer is prepared, and the surface plate fixing adhesive laminated film is placed on one surface of the base film with the surface plate fixing adhesive layer facing the base film. On the other hand, the abrasive film fixing pressure-sensitive adhesive layer laminated film is laminated on the other surface of the base film so that the abrasive fixing pressure-sensitive adhesive layer faces the base film. Is made.
Then, by pressing the laminate in the thickness direction with a rubber roller or the like, the surface plate fixing adhesive layer, the base material layer and the abrasive fixing adhesive layer are laminated and integrated in this order, and A double-sided adhesive tape for fixing an abrasive, in which a release film is laminated and integrated so as to be peelable on the surface of the pressure-sensitive adhesive layer for fixing a board and the pressure-sensitive adhesive layer for fixing an abrasive, can be obtained.

ADVANTAGE OF THE INVENTION According to this invention, the adhesive composition which can obtain the adhesive tape which is excellent in resilience resistance and is excellent also in the handleability, and the adhesive tape using this adhesive composition can be provided.

It is a schematic diagram explaining living radical polymerization. It is a schematic diagram explaining the case where the acrylic polymer obtained by living radical polymerization is bridge | crosslinked. It is a schematic diagram explaining free radical polymerization. It is a schematic diagram explaining the case where the acrylic polymer obtained by free radical polymerization is bridge | crosslinked. It is the figure which showed the test method of the resilience resistance in an Example.

Hereinafter, embodiments of the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

<Preparation of acrylic polymer having crosslinkable functional group>
(Polymer 1)
Tellurium (40 mesh, metal tellurium, Aldrich) 6.38 g (50 mmol) was suspended in tetrahydrofuran (THF) 50 mL, and 1.6 mol / L n-butyllithium / hexane solution (Aldrich) 34 4 mL (55 mmol) was slowly added dropwise at room temperature. The reaction solution was stirred until the metal tellurium disappeared completely. To this reaction solution, 10.7 g (55 mmol) of ethyl-2-bromo-isobutyrate was added at room temperature and stirred for 2 hours. After completion of the reaction, the solvent was concentrated under reduced pressure, followed by distillation under reduced pressure to obtain a yellow oily ethyl 2-methyl-2-n-butylteranyl-propionate.

In a glove box substituted with argon, in a reaction vessel, 19 μL of the produced ethyl 2-methyl-2-n-butylterranyl-propionate, V-60 (2,2′-azobisisobutyronitrile, Wako Pure Chemical Industries, Ltd.) After adding 1.4 mg and 1 mL of ethyl acetate, the reaction vessel was sealed, and the reaction vessel was taken out of the glove box. Subsequently, while flowing argon gas into the reaction vessel, a mixed monomer (82 parts by weight of 2-ethylhexyl acrylate (2EHA), 10 parts by weight of butyl acrylate (BA), ethyl acrylate (EA) was introduced into the reaction vessel. ) 5 parts by weight, acrylic acid (AAc) 2.9 parts by weight, and 2-hydroxyethyl acrylate (HEA) 0.1 part by weight) in total 100 g, and 66.5 g of ethyl acetate as a polymerization solvent were added. A polymerization reaction was carried out at 20 ° C. for 20 hours to obtain a living radical polymerized acrylic polymer-containing solution.
The obtained acrylic polymer-containing solution was diluted 50-fold with tetrahydrofuran (THF), and the resulting diluted solution was filtered with a filter (material: polytetrafluoroethylene, pore diameter: 0.2 μm). Supplied to a gel permeation chromatograph (manufactured by Waters, 2690 Separations Model), GPC measurement was performed under the conditions of a sample flow rate of 1 ml / min and a column temperature of 40 ° C., and the molecular weight in terms of polystyrene of the polymer was measured. Molecular weight (Mw) and molecular weight distribution (Mw / Mn) were determined. GPC KF-806L (manufactured by Showa Denko) was used as the column, and a differential refractometer was used as the detector.

(Polymers 2-6)
Living radical polymerization was conducted in the same manner as Polymer 1 except that the amounts of ethyl 2-methyl-2-n-butylterranyl-propionate and V-60 and the composition of the mixed monomer were as shown in Table 1. An acrylic polymer-containing solution was obtained, and the weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the obtained acrylic polymer were determined.

(Polymer 7)
50 g of ethyl acetate was added as a polymerization solvent in the reaction vessel, and after bubbling with nitrogen, the reaction vessel was heated while flowing nitrogen and refluxing was started. Next, a polymerization initiator solution in which 0.1 g of V-60 (2,2′-azobisisobutyronitrile, manufactured by Wako Pure Chemical Industries, Ltd.) as a polymerization initiator was diluted 10-fold with ethyl acetate was charged into the reaction vessel. Then, a total of 100 g of mixed monomers (96.7 parts by weight of butyl acrylate, 3 parts by weight of acrylic acid, and 0.3 parts by weight of 2-hydroxyethyl acrylate) were added dropwise to the reaction vessel over 2 hours. After completion of the dropping, a polymerization initiator solution obtained by diluting 0.08 g of V-60 as a polymerization initiator 10 times with ethyl acetate was again put into the reaction vessel, and the polymerization reaction was carried out for 5 hours, thereby carrying out free radical polymerization. A polymer-containing solution was obtained.
About the obtained acrylic polymer, it carried out similarly to the polymer 1, and calculated | required the weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn).

<Preparation of tackifying resin>
(Tackifying resin 1)
As tackifying resin 1, YS Polystar NH (manufactured by Yasuhara Chemical Co., Ltd., hydrogenated terpene phenol resin, alcoholic hydroxyl value 130 mgKOH / g, 2.8 alcoholic hydroxyl groups contained in one molecule, softening point 130 ° C.) is used. It was.

(Tackifying resin 2)
In a 5 L stainless steel autoclave, 400 g of YS Polystar G150 (manufactured by Yasuhara Chemical Co., Ltd., terpene phenol resin), 2 L of 2-propanol, and 10.0 g of a powdery 5% ruthenium-supported alumina catalyst were charged.
Next, this was sealed, and the atmosphere was replaced with nitrogen gas, and then introduced while applying a pressure of 10 kg / cm ² of hydrogen gas. Then, the mixture was heated with stirring to 150 ° C., and the pressure of hydrogen was 40 kg / cm ^2, and the reaction was carried out for 14 hours while maintaining the pressure at 40 kg / cm ² by supplementing the absorbed hydrogen. Thereafter, the mixture was cooled to room temperature, 500 mL of ethanol was added to the obtained suspension, and suction filtration was performed with a Buchner funnel, and the catalyst was filtered off. The filtrate was finally distilled and concentrated at 150 ° C. and a vacuum degree of 1 mmHg or less over 30 minutes to obtain 380 g of a highly viscous tackifying resin 2.
The obtained tackifying resin 2 had an alcoholic hydroxyl value of 73 mgKOH / g, 1.7 alcoholic hydroxyl groups contained in one molecule, and a softening point of 147 ° C.

(Tackifying resin 3)
Using YS Polystar T145 (manufactured by Yashara Chemical Co., Ltd., terpene phenol resin), tackifying resin 3 was obtained in the same manner as the hydrogenation method for obtaining tackifying resin 2.
The obtained tackifying resin 3 had an alcoholic hydroxyl value of 66 mgKOH / g, 1.5 alcoholic hydroxyl groups contained in one molecule, and a softening point of 145 ° C.

(Tackifying resin 4)
As the tackifier resin 4, a rosin resin having an alcoholic hydroxyl value of 85 mgKOH / g, 1.8 alcoholic hydroxyl groups contained in one molecule, and a softening point of 150 ° C. was prepared.

(Tackifying resin 5)
As the tackifier resin 5, a rosin resin having an alcoholic hydroxyl value of 75 mgKOH / g, 1.6 alcoholic hydroxyl groups contained in one molecule, and a softening point of 150 ° C. was prepared.

(Tackifying resin 6)
As the tackifier resin 6, Pencel D135 (manufactured by Arakawa Chemical Industry Co., Ltd., polymerized rosin ester resin, alcoholic hydroxyl value 45 mgKOH / g, 0.7 alcoholic hydroxyl groups contained in one molecule, softening point 135 ° C.) is used. It was.

(Tackifying resin 7)
As the tackifier resin 7, super ester A115 (Arakawa Chemical Industries, rosin ester resin, alcoholic hydroxyl value 19 mgKOH / g, 0.25 alcoholic hydroxyl group contained in one molecule, softening point 115 ° C.) is used. It was.

(Tackifying resin 8)
Mighty Ace G150 (manufactured by Yasuhara Chemical Co., Ltd., terpene phenol resin, phenolic hydroxyl value 130 mgKOH / g, 3.0 phenolic hydroxyl groups contained in one molecule, softening point 150 ° C.) was used as the tackifier resin 8.

(Tackifying resin 9)
As tackifier resin 9, a rosin resin having an alcoholic hydroxyl value of 75 mgKOH / g, 1.4 alcoholic hydroxyl groups contained in one molecule, and a softening point of 140 ° C. was prepared.

(Examples 1 to 10, Comparative Examples 1 to 8)
Ethyl acetate is added to 100 parts by weight of the nonvolatile content of the obtained acrylic polymer-containing solution and stirred, and the resulting tackifier resin and an isocyanate-based crosslinking agent as a crosslinking agent (Coronate L, manufactured by Nippon Polyurethane Co., Ltd.) Were added in the amounts shown in Tables 2 and 3 and stirred to obtain an adhesive solution having a nonvolatile content of 30% by weight. The obtained pressure-sensitive adhesive solution was applied to a PET film having a thickness of 50 μm which was subjected to a release treatment in Examples 1 to 6 and Comparative Examples 1 to 4 so that the paste had a thickness of 10 μm after drying. In No. 10 and Comparative Examples 5 to 8, coating was performed so that the glue thickness would be 20 μm after drying, followed by drying at 100 ° C. for 10 minutes to obtain a non-support type double-sided pressure-sensitive adhesive tape. In addition, the release film for protecting an adhesive layer was laminated | stacked on the surface of the both sides of an adhesive layer.

The obtained double-sided pressure-sensitive adhesive tape was cut into a flat rectangular shape of 50 mm × 100 mm to prepare a test piece. After the test piece was immersed in ethyl acetate at 23 ° C. for 24 hours, the test piece was taken out from ethyl acetate and heated to 110 ° C. Dry under conditions for 1 hour. The weight of the test piece after drying was measured, and the gel fraction was calculated using the following formula.
Gel fraction (% by weight) = 100 × (W2-W0) / (W1-W0)
(W0: weight of substrate, W1: weight of test piece before immersion, W2: weight of test piece after immersion and drying)

(Evaluation)
The following evaluation was performed about the double-sided adhesive tape obtained by the Example and the comparative example. The results are shown in Tables 2 and 3.

(1) Evaluation of adhesive residue on punching blade When double-sided adhesive tape was punched 30 times with a 50 mm x 50 mm Thomson blade, visual check was made for the occurrence of adhesion (adhesive residue) of the sheet-like interlayer filling material to the Thomson blade And evaluated as follows.
○: No adhesive residue on the punching blade was observed. Δ: Adhesive residue on the punching blade was recognized, but there was no effect on continuous use. ×: Adhesive residue on the punching blade was observed. Continued use was difficult

(2) Resilience test FIG. 5 shows a test method for resilience. As shown in FIG. 5, the obtained double-sided adhesive tape was cut into a flat rectangular shape of 25 mm wide × 150 mm long to produce a test piece 1, and a release film provided on both sides of the test piece 1 was peeled off The pressure-sensitive adhesive layer was exposed by removing.
Thereafter, an aluminum plate 2 having a width of 25 mm, a length of 150 mm and a thickness of 0.3 mm was superimposed on the surface of the test piece 1, and a polycarbonate resin plate 3 having a width of 25 mm × length of 200 mm × thickness of 1 mm was superimposed on the back surface of the test piece 1. In addition, it adjusted so that the test piece 1 might be located in the center part of the length direction of the polycarbonate resin board 3. FIG.
Next, a 2 kg rubber roller is reciprocated once on the polycarbonate resin plate 3 at a speed of 300 mm / min so that the polycarbonate resin plate 3 and the aluminum plate 2 are integrated through the test piece 1 at 23 ° C. for 24 hours. By leaving still, the test sample 4 in which the aluminum plate 2 was stuck and integrated with the central part of the vertical direction of the polycarbonate resin plate 3 through the test piece 1 was produced.
Subsequently, as shown in FIG. 5, the test sample 4 is set on the jig 5, and bending stress is applied in the longitudinal direction of the test sample 4 to thereby fix the test sample 4 to both ends in the length direction of the polycarbonate resin plate 3. The test sample 4 was deformed into an arc shape so that the distance between them was 180 mm. In this state, the test sample 4 was placed in an 85 ° C. oven and allowed to stand for 24 hours.
Thereafter, the test sample 4 is taken out from the oven while being curved in an arc shape, the height H (mm) of the floating between the aluminum plate 2 and the polycarbonate resin plate 3 is measured with a caliper, and the average value is measured. It was set as the value of evaluation of resilience.
Here, the height H (mm) of the float between the aluminum plate 2 and the polycarbonate resin plate 3 of the test sample 4 is the aluminum plate 2 and the polycarbonate resin plate 3 in the direction perpendicular to the upper surface of the jig 5. The position where the distance between the opposing surfaces of the aluminum plate 2 takes the maximum value is specified, and at this position, the test piece is determined from the distance between the opposing surfaces of the aluminum plate 2 and the polycarbonate resin plate 3 in the direction perpendicular to the upper surface of the jig 5. The value obtained by reducing the thickness of 1.
○: Floating height is 1.0 mm or less Δ: Floating height exceeds 1.0 mm but 2.5 mm or less ×: Floating height is larger than 2.5 mm

(3) Evaluation of constant load peelability Adhere a backing adhesive tape with a width of 20 mm x 50 mm to a polycarbonate resin plate, and after curing at 23 ° C and 50% humidity overnight, apply a load of 50 g in the direction of 90 ° at 85 ° C. The peeling distance (peeling length) after 30 minutes was measured.

(4) Evaluation of adhesive strength at 23 ° C. A lined adhesive tape having a width of 25 mm × 75 mm was attached to a polycarbonate (PC) plate and cured at 23 ° C. and 50% humidity for 20 minutes. Thereafter, in accordance with JIS Z 0237: 2009, a 180 ° peel test was performed under the condition of a tensile speed of 300 mm / min, and the adhesive strength (N / 25 mm) at 23 ° C. was measured.

(5) Evaluation of heat-sensitive adhesive strength at 80 ° C. A backed adhesive tape having a width of 25 mm × 75 mm was attached to a polycarbonate (PC) plate and further heated at 80 ° C. for 3 hours. After returning to 23 ° C., a 180 ° peel test was performed in accordance with JIS Z 0237: 2009 under the condition of a tensile speed of 300 mm / min, and the heat-sensitive adhesive force (N / 25 mm) was measured.

(6) Evaluation of adhesive residue After evaluation of the heat-sensitive adhesive force, the surface of the polycarbonate (PC) plate from which the adhesive tape was peeled was visually observed. The case where a slight adhesive residue was recognized was evaluated as “◯”, and the case where a large amount of adhesive residue was observed was evaluated as “x”.

ADVANTAGE OF THE INVENTION According to this invention, the adhesive composition which can obtain the adhesive tape which is excellent in resilience resistance and is excellent also in the handleability, and the adhesive tape using this adhesive composition can be provided.

11 Acrylic polymer 111 obtained by living radical polymerization 111 Monomer not containing a crosslinkable functional group 112 Crosslinkable functional group-containing monomer 12 Acrylic polymer 121 obtained by free radical polymerization 121 Monomer 122 not containing a crosslinkable functional group Crosslinkability Functional group-containing monomer 123 Polymer whose growth terminal radical is deactivated during the reaction 124 Polymer grown by radical species newly generated during the reaction 1 Test piece 2 Aluminum plate 3 Polycarbonate resin plate 4 Test sample 5 Jig H Aluminum plate and polycarbonate Height of float between resin plates (mm)

Claims (8)

1. A pressure-sensitive adhesive composition comprising: a polymer component containing an acrylic polymer having a crosslinkable functional group; a tackifying resin having a hydroxyl value of an alcoholic hydroxyl group of 70 mgKOH / g or more; and a crosslinking agent.
2. The pressure-sensitive adhesive composition according to claim 1, wherein the tackifying resin having a hydroxyl value of an alcoholic hydroxyl group of 70 mgKOH / g or more has 1.6 or more alcoholic hydroxyl groups contained in one molecule.
3. The pressure-sensitive adhesive composition according to claim 1 or 2, wherein the tackifying resin having a hydroxyl value of an alcoholic hydroxyl group of 70 mgKOH / g or more has a softening temperature of 100 to 180 ° C.
4. The acrylic polymer having a crosslinkable functional group has a content of a component derived from an acrylic monomer having a crosslinkable functional group in an amount of 0.01 to 20% by weight. The pressure-sensitive adhesive composition described.
5. The acrylic polymer having a crosslinkable functional group has a weight average molecular weight of 300,000 to 2,000,000 and a molecular weight distribution (Mw / Mn) of 1.05 to 2.5. 3. The pressure-sensitive adhesive composition according to 3 or 4.
6. The pressure-sensitive adhesive composition according to claim 1, 2, 3, 4, or 5, wherein the acrylic polymer having a crosslinkable functional group is an acrylic polymer obtained by living radical polymerization.
7. 5. The tackifier resin having a hydroxyl value of an alcoholic hydroxyl group of 70 mgKOH / g or more per 5 parts by weight of an acrylic polymer having a crosslinkable functional group, The pressure-sensitive adhesive composition according to 3, 4, 5 or 6.
8. An adhesive tape comprising an adhesive layer comprising the adhesive composition according to claim 1, 2, 3, 4, 5, 6 or 7.

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