KR102590639B1 - adhesive tape - Google Patents

Abstract

The purpose of the present invention is to provide an adhesive tape that can reduce adhesion due to high temperature and can also be used for materials that do not transmit light.
The present invention is an adhesive tape having an adhesive layer, wherein the adhesive layer has a shear storage modulus at 25°C evaluated by dynamic viscoelasticity measurement of 4.0 × 10 ⁴ to 2.0 × 10 ⁶ Pa, and the adhesive layer has the above This adhesive tape has a logarithmic contact angle of 80° or more after attaching the adhesive layer side of the adhesive tape to glass, heating it at 220° C. for 120 minutes, and peeling it off.

Description

adhesive tape

The present invention relates to adhesive tapes.

In the semiconductor chip manufacturing process, adhesive tapes are used to facilitate handling of wafers and semiconductor chips during processing and to prevent damage. For example, when a thick film wafer cut from a high-purity silicon single crystal or the like is ground to a predetermined thickness to form a thin film wafer, grinding is performed after attaching an adhesive tape to the thick film wafer.

Such adhesive tapes have high adhesive properties that allow them to firmly fix adherends such as wafers and semiconductor chips during the processing process, and can be peeled off without damaging the adherends such as wafers and semiconductor chips after the process is completed. It is required to be present (hereinafter also referred to as “high adhesion and easy peeling”).

As an adhesive tape that achieves high adhesion and ease of peeling, Patent Document 1 discloses an adhesive tape using a photocurable adhesive that is cured by irradiation of light such as ultraviolet rays and the adhesive strength is reduced. By using a photocurable adhesive as an adhesive, the adherend can be reliably fixed during the processing process and can be easily peeled off by irradiating ultraviolet rays or the like.

Japanese Patent Publication No. 5-32946

In the manufacturing process of electronic components such as semiconductor chips, high-temperature treatment that applies heat of 200 ℃ or higher is sometimes performed, and the adhesive tape used in such manufacturing process requires heat resistance and adhesion resistance that does not increase adhesion even at high temperatures. do. Conventionally, a photocurable adhesive tape such as Patent Document 1 has been used to reduce adhesion increase due to high temperature. On the other hand, in the manufacture of electronic components, there are cases where a wafer or substrate is fixed to a support plate through a double-sided adhesive tape, and processing such as wiring is performed. However, in recent years, from the viewpoint of cost and handling, opaque materials such as copper, aluminum, and glass epoxy are increasingly used as support plates. With such opaque support plates, adhesive tapes using conventional photocurable adhesives cannot be cured. There is a problem that cannot be done.

The purpose of the present invention is to provide an adhesive tape that can reduce adhesion due to high temperature and can also be used for materials that do not transmit light.

The present invention is an adhesive tape having an adhesive layer, wherein the adhesive layer has a shear storage modulus at 25°C evaluated by dynamic viscoelasticity measurement of 4.0 × 10 ⁴ to 2.0 × 10 ⁶ Pa, and the adhesive layer has the above This adhesive tape has a logarithmic contact angle of 80° or more after attaching the adhesive layer side of the adhesive tape to glass, heating it at 220° C. for 120 minutes, and peeling it off.

The present invention is described in detail below.

An adhesive tape according to an embodiment of the present invention has an adhesive layer.

The adhesive tape of one embodiment of the present invention may have other layers as long as it has an adhesive layer. Moreover, the adhesive tape which is one embodiment of this invention may be a support type with a base material, or may be a non-support type without a base material. When the adhesive tape of one embodiment of the present invention has a base material, it suffices to have an adhesive layer on at least one side of the base material, and may be a single-sided adhesive tape or a double-sided adhesive tape.

The adhesive layer has a shear storage modulus of 4.0 × 10 ⁴ to 2.0 × 10 ⁶ Pa at 25°C, as evaluated by dynamic viscoelasticity measurement.

When the shear storage modulus of the adhesive layer is 4.0 x 10 ⁴ Pa or more, the adhesive layer can have a hardness suitable for an adhesive tape. In addition, when the shear storage modulus of the adhesive layer is 2.0 × 10 ⁶ Pa or less, the adhesive layer does not become too hard, preventing the adhesive tape from adhering and suppressing glue residue. From the same viewpoint as above, the preferable lower limit of the shear storage modulus is 8.0×10 ⁴ Pa, and the more preferable lower limit is 1.0×10 ⁵ Pa. ^{The preferable} upper limit ^of the shear storage modulus is ^1.5 It is 10 ⁵ Pa.

The shear storage modulus was measured at -50°C at a temperature increase rate of 5°C/min at an angular frequency of 10 Hz in the shear mode of dynamic viscoelasticity measurement using a dynamic viscoelasticity measurement device (e.g., DVA-200, manufactured by IT Instrumentation Control Co., Ltd.). Among the measured values obtained by measuring up to 200°C, it can be obtained as the value of the storage elastic modulus at 25°C.

Additionally, the shear storage modulus has little variation due to temperature. Therefore, if the adhesive tape of one embodiment of the present invention has a shear storage modulus in the above range at 25°C, the above effect is exhibited even at a high temperature of about 220°C.

The adhesive layer has a logarithmic contact angle (hereinafter simply referred to as the logarithmic contact angle after heating) of the adhesive tape after attaching it to glass and heating at 220°C for 120 minutes and peeling it off, which is 80° or more.

The adhesive tape is attached to glass and heated, and the adhesive layer after peeling has a logarithmic contact angle in the above range. As a result, the surface becomes hydrophobic and it becomes difficult to interact with the adherend, thereby reducing adhesion enhancement due to heating. You can do it. From the same viewpoint, the preferable lower limit of the logarithmic contact angle after heating is 81°, the more preferable lower limit is 81.5°, and the more preferable lower limit is 82°. The preferable upper limit of the logarithmic contact angle after heating is 110°, a more preferable upper limit is 105°, an even more preferable upper limit is 103°, an even more preferable upper limit is 100°, a particularly preferable upper limit is 97°, a particularly preferable upper limit is 95°, very preferable. The upper limit is 92°, and a more desirable upper limit is 91°.

The logarithmic contact angle after heating can be measured by a method based on JIS R 3257:1999, and can specifically be measured by the following method.

Cut the adhesive tape to a width of 25 mm. The cut adhesive tape is pressed onto a glass adherend (e.g., large slide glass white-polished No. 2 manufactured by Matsunami Glass Industry Co., Ltd.) at room temperature 23°C and relative humidity 50% with a 2 kg rubber roller. Attach at a speed of 10 mm/sec using . Next, heat treatment at 220°C for 120 minutes is performed. After standing to cool, the adhesive tape is peeled off from the glass adherend, and the logarithmic contact angle of the adhesive layer is measured using a contact angle measuring device (for example, CAM 200, manufactured by KSV) according to JIS R 3257:1999. Specifically, in an environment of room temperature of 25°C and humidity of 40%, 2 µl of water droplets (ultrapure water) are dropped on the surface of the adhesive layer of an adhesive tape placed horizontally. The angle formed between pure water and the surface of the adhesive layer 5 seconds after dropping is taken as the logarithmic contact angle.

In the adhesive tape according to an embodiment of the present invention, the adhesive layer preferably has a logarithmic contact angle of 103° or less at 25°C.

When the logarithmic contact angle of the adhesive layer at 25°C is 103° or less, it can be attached to the adherend with more appropriate adhesive force (initial adhesive force). From the same viewpoint, the more preferable upper limit of the logarithmic contact angle at 25°C of the pressure-sensitive adhesive layer is 102°, and the more preferable upper limit is 100°. The lower limit of the logarithmic contact angle of the adhesive layer at 25°C is not particularly limited, but is preferably 80°. The logarithmic contact angle at 25°C of the adhesive layer can be measured by the same method as the logarithmic contact angle after heating, except that no heat treatment is performed.

The adhesive layer preferably contains an adhesive having a crosslinkable functional group, a silicone-based graft copolymer having a crosslinkable functional group, and a crosslinking agent capable of reacting with the adhesive and the silicone-based graft copolymer to crosslink the adhesive.

When the adhesive layer contains a crosslinking agent, it is possible to easily adjust the shear storage modulus to the above range by crosslinking the adhesive. In addition, when the adhesive layer contains a silicone-based graft copolymer, the silicone-based graft copolymer bleeds out to the surface of the adhesive layer by heating, thereby making the surface of the adhesive layer hydrophobic, making it easy to adjust the logarithmic contact angle after heating to the above range. can do. In addition, when the surface of the adhesive layer becomes hydrophobic, it becomes difficult for the adhesive layer and the adherend to interact, and the adhesive force decreases, thereby reducing the increase in adhesion. Additionally, because the silicone-based graft copolymer has a crosslinkable functional group, the silicone-based graft copolymer can be bonded to the adhesive via a crosslinking agent, thereby suppressing contamination of the adherend.

The adhesive is not particularly limited and may be of a curing type or a non-curing type.

A cured adhesive is one that has a polymerizable functional group such as a double bond and is cured by stimulation such as heat or light, while a non-curable adhesive is one that does not substantially have a polymerizable functional group. It is preferable that the adhesive is a non-curing type adhesive because the manufacturing process can be simplified and it can be used even for opaque materials that cannot be photocured. Non-curing adhesives include, for example, non-light curing adhesives, non-thermal curing adhesives, and non-energy curing adhesives.

Examples of the adhesive include acrylic adhesives, silicone adhesives, urethane adhesives, and rubber adhesives. Among them, a non-silicone adhesive is preferable, and an acrylic adhesive is more preferable because it is easy to control the logarithmic contact angle after heating and the shear storage modulus.

The crosslinkable functional groups present in the adhesive and the silicone-based graft copolymer each independently include, for example, a carboxyl group, a hydroxyl group, a glycidyl group, an amino group, an amide group, and a nitrile group. Among them, carboxyl group is preferable because it is easy to adjust the shear storage modulus to the range described above.

The adhesive is preferably an acrylic polymer with a molecular weight distribution (Mw/Mn) of 1.05 to 2.5, and is an acrylic polymer with a molecular weight distribution (Mw/Mn) of 1.05 to 2.5 obtained by living radical polymerization (hereinafter simply referred to as “living radical polymerization acrylic polymer”). (also referred to as “polymer”) is more preferable.

The living radical polymerization acrylic polymer is an acrylic polymer obtained by using an acrylic monomer such as (meth)acrylic acid ester or (meth)acrylic acid as a raw material and by living radical polymerization, preferably using an organic tellurium polymerization initiator. . Living radical polymerization is polymerization in which molecular chains grow without the polymerization reaction being interrupted by side reactions such as stopping reactions or chain transfer reactions. According to living radical polymerization, for example, compared to free radical polymerization, a polymer with a more uniform molecular weight and composition is obtained, and the production of low molecular weight components, etc. can be suppressed, so that glue residue is suppressed even when high temperature treatment is performed. can do. In addition, the shear storage modulus can be easily adjusted to the above range. From the viewpoint of further suppressing residual glue, the more preferable lower limit of the molecular weight distribution of the living radical polymerization acrylic polymer is 1.1, and the more preferable upper limit is 2.0.

In the living radical polymerization, various polymerization methods may be employed. For example, an iron, ruthenium or copper catalyst and a halogen-based initiator may be used (ATRP), TEMPO may be used, or an organic tellurium polymerization initiator may be used. Among these, it is preferable to use an organic tellurium polymerization initiator. Living radical polymerization using an organic tellurium polymerization initiator, unlike other living radical polymerizations, does not protect all radically polymerizable monomers with polar functional groups such as hydroxyl groups or carboxyl groups, but polymerizes them with the same initiator to have a uniform molecular weight and composition. polymer can be obtained. For this reason, a 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 in living radical polymerization, and examples include organic tellurium compounds and organic telluride compounds.

As the organic tellurium compound, for example, (methyltellanyl-methyl)benzene, (1-methyltellanyl-ethyl)benzene, (2-methyltellanyl-propyl)benzene, 1-chloro-4-(methyl tellanyl-methyl)benzene, 1-hydroxy-4-(methyltellanyl-methyl)benzene, 1-methoxy-4-(methyltellanyl-methyl)benzene, 1-amino-4-(methyltellanyl- Methyl)benzene, 1-nitro-4-(methyltellanyl-methyl)benzene, 1-cyano-4-(methyltellanyl-methyl)benzene, 1-methylcarbonyl-4-(methyltellanyl-methyl) Benzene, 1-phenylcarbonyl-4-(methyltellanyl-methyl)benzene, 1-methoxycarbonyl-4-(methyltellanyl-methyl)benzene, 1-phenoxycarbonyl-4-(methyltellanyl) -methyl)benzene, 1-sulfonyl-4-(methyltellanyl-methyl)benzene, 1-trifluoromethyl-4-(methyltellanyl-methyl)benzene, 1-chloro-4-(1-methyltel) ranyl-ethyl)benzene, 1-hydroxy-4-(1-methyltellanyl-ethyl)benzene, 1-methoxy-4-(1-methyltellanyl-ethyl)benzene, 1-amino-4-(1 -Methyltellanyl-ethyl)benzene, 1-nitro-4-(1-methyltellanyl-ethyl)benzene, 1-cyano-4-(1-methyltellanyl-ethyl)benzene, 1-methylcarbonyl- 4-(1-methyltellanyl-ethyl)benzene, 1-phenylcarbonyl-4-(1-methyltellanyl-ethyl)benzene, 1-methoxycarbonyl-4-(1-methyltellanyl-ethyl) Benzene, 1-phenoxycarbonyl-4-(1-methyltellanyl-ethyl)benzene, 1-sulfonyl-4-(1-methyltellanyl-ethyl)benzene, 1-trifluoromethyl-4-( 1-methyltellanyl-ethyl)benzene, 1-chloro-4-(2-methyltellanyl-propyl)benzene, 1-hydroxy-4-(2-methyltellanyl-propyl)benzene, 1-methoxy- 4-(2-methyltellanyl-propyl)benzene, 1-amino-4-(2-methyltellanyl-propyl)benzene, 1-nitro-4-(2-methyltellanyl-propyl)benzene, 1-cyano No-4-(2-methyltellanyl-propyl)benzene, 1-methylcarbonyl-4-(2-methyltellanyl-propyl)benzene, 1-phenylcarbonyl-4-(2-methyltellanyl-propyl) ) Benzene, 1-methoxycarbonyl-4-(2-methyltellanyl-propyl)benzene, 1-phenoxycarbonyl-4-(2-methyltellanyl-propyl)benzene, 1-sulfonyl-4- (2-methyltellanyl-propyl)benzene, 1-trifluoromethyl-4-(2-methyltellanyl-propyl)benzene, 2-(methyltellanyl-methyl)pyridine, 2-(1-methyltellanyl) -Ethyl)pyridine, 2-(2-methyltellanyl-propyl)pyridine, 2-methyltellanyl-methyl ethanoate, 2-methyltellanyl-methyl propionate, 2-methyltellanyl-2-methylmethyl propionate, 2 -Methyltellanyl-ethyl ethanoate, 2-methyltellanyl-ethyl propionate, 2-methyltellanyl-2-methylethyl propionate, 2-methyltellanylacetonitrile, 2-methyltellanylpropionitrile, 2-methyl -2-methyltellanylpropionitrile, etc. can be mentioned. The methyltellanyl group in these organic tellurium compounds may be ethyltellanyl group, n-propyltellanyl group, isopropyltellanyl group, n-butyltellanyl group, isobutyltellanyl group, t-butyltellurium group, phenyltellanyl group, etc. Moreover, these organic tellurium compounds may be used individually, or two or more types may be used together.

As the organic telluride compound, for example, dimethylditelluride, diethylditelluride, di-n-propylditelluride, diisopropylditelluride, dicyclopropylditelluride, di-n-butyl Ditelluride, di-sec-butylditelluride, 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, dinaph Examples include tilditelluride and dipyridylditelluride. These organic telluride compounds may be used individually, or two or more types may be used together. Among them, dimethylditelluride, diethylditelluride, di-n-propylditelluride, di-n-butylditelluride, and diphenylditelluride are preferable.

Additionally, within the range that does not impair the effect of the present invention, an azo compound may be used as a polymerization initiator in addition to the organic tellurium polymerization initiator for the purpose of promoting the polymerization rate.

The azo compound is not particularly limited as long as it is commonly used in radical polymerization. For example, 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2-methylbutyronitrile) ), 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-cyanovalerian 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-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'-azobis( 2-amidinopropane) dihydrochloride, 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropionamidine] tetrahydrate, 2,2'-azobis(1-imino-1) -pyrrolidino-2-methylpropane) dihydrochloride, 2,2'-azobis(2,4,4-trimethylpentane), etc. These azo compounds may be used individually, or two or more types may be used together.

Since the adhesive has a crosslinkable functional group, a monomer having a crosslinkable functional group is blended with the living radical polymerization acrylic polymer as a polymerizable monomer.

When the crosslinkable functional group is a carboxyl group, examples of the monomer having a carboxyl group include (meth)acrylic acid.

When the crosslinkable functional group is a hydroxyl group, examples of the monomer having a hydroxyl group include (meth)acrylic acid having a hydroxyl group such as 4-hydroxybutyl (meth)acrylate and 2-hydroxyethyl (meth)acrylate. Ester may be mentioned.

When the crosslinkable functional group is a glycidyl group, examples of the monomer having a glycidyl group include glycidyl (meth)acrylate.

When the crosslinkable functional group is an amide group, examples of monomers having an amide group include hydroxyethyl acrylamide, isopropylacrylamide, and dimethylaminopropylacrylamide.

When the crosslinkable functional group is a nitrile group, examples of the monomer having a nitrile group include acrylonitrile.

When using the acrylic monomer having the carboxyl group, its content is not particularly limited, but the preferred lower limit in the radically polymerizable monomer polymerized in the living radical polymerization is 0.1% by weight, and the preferred upper limit is 10% by weight. If the content is 0.1% by weight or more, the living radical polymerization acrylic polymer can sufficiently bond to the silicone graft copolymer via the crosslinking agent, thereby reducing contamination of the adherend. If the content is 10% by weight or less, the adhesive does not become too hard and the remaining glue on the adhesive tape can be suppressed.

When the (meth)acrylic acid ester having the hydroxyl group is used, its content is not particularly limited, but the preferable upper limit in the radically polymerizable monomer polymerized in the living radical polymerization is 30% by weight. When the content is 30% by weight or less, the heat-resistant adhesiveness of the adhesive can be further improved.

The acrylic monomer to be polymerized in the living radical polymerization may be a radically polymerizable monomer other than the acrylic monomer having a crosslinkable functional group. Examples of the other radically polymerizable monomers include other (meth)acrylic acid esters. Additionally, acrylic monomers having other polar functional groups such as amino groups, amide groups, and nitrile groups can also be used. Additionally, 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 include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, and tert-butyl (meth)acrylate. Latex, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, isononyl (meth)acrylate, isomyristyl (meth)acrylate, stearyl (meth)acrylate ) Acrylates such as (meth)acrylic acid alkyl esters, 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, etc. are mentioned. These (meth)acrylic acid esters may be used individually, or two or more types may be used together.

The vinyl compound is not particularly limited and includes, for example, N,N-dimethylacrylamide, N,N-diethylacrylamide, N-isopropylacrylamide, N-hydroxyethylacrylamide, acrylamide, etc. Meth)acrylamide compounds, N-vinylpyrrolidone, N-vinyl caprolactam, N-vinylacetamide, N-acryloylmorpholine, acrylonitrile, styrene, vinyl acetate, etc. These vinyl compounds may be used individually, or two or more types may be used together.

In the living radical polymerization, a dispersion stabilizer may be used. Examples of the dispersion stabilizer include polyvinylpyrrolidone, polyvinyl alcohol, methylcellulose, ethylcellulose, poly(meth)acrylic acid, poly(meth)acrylic acid ester, and polyethylene glycol.

As a method of the living radical polymerization, conventionally known methods are used, and examples include solution polymerization (boiling point polymerization or constant temperature polymerization), emulsion polymerization, suspension polymerization, and bulk polymerization.

When a polymerization solvent is used in the living radical polymerization, the polymerization solvent is not particularly limited. Examples of the polymerization solvent include non-polar solvents such as hexane, cyclohexane, octane, toluene, and xylene, water, methanol, ethanol, propanol, butanol, acetone, methyl ethyl ketone, methyl isobutyl ketone, and tetrahydro. Highly polar solvents such as furan, dioxane, and N,N-dimethylformamide can be used. These polymerization solvents may be used individually, or two or more types may be used together.

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

The living radical polymerization acrylic polymer has a molecular weight of a preferred lower limit of 500,000, a more preferred lower limit of 800,000, a preferred upper limit of 1.5 million, and a more preferred upper limit of 1.2 million. When the molecular weight of the living radically polymerized acrylic polymer is within the above range, it is possible to easily adjust the logarithmic contact angle after heating and the shear storage modulus within the above range.

The silicone-based graft copolymer is not particularly limited as long as it has a crosslinkable functional group. The crosslinkable functional group may exist in the graft chain, may exist in the main chain, or may exist in the graft chain and the main chain.

From the viewpoint of reducing contamination to the adherend, the silicone-based graft copolymer preferably contains a polar functional group-containing monomer and a structural unit derived from a silicone macromonomer. From the viewpoint of reducing contamination to the adherend, the silicone-based graft copolymer is preferably a graft copolymer having a side chain containing silicon. Examples of the polar functional group-containing monomer include hydroxyl group-containing monomers, amino group-containing monomers, and hydroxyl group-containing monomers. Among these, from the viewpoint of easy control of adhesive force, it is preferable that the polar functional group-containing monomer is a carboxyl group-containing monomer.

When the polar functional group-containing monomer is a carboxyl group-containing monomer, from the viewpoint of further improving the initial adhesive strength and the adhesive strength after heating, the silicone-based graft copolymer is preferably 0.1% by weight or more, preferably 90% by weight. It is preferable that it is obtained by copolymerizing mixed monomers containing not more than % by weight of carboxyl group-containing monomers. The content of the carboxyl group-containing monomer is more preferably 0.5% by weight or more, and even more preferably 1% by weight or more. Moreover, the content of the carboxyl group-containing monomer is more preferably 80% by weight or less, further preferably 70% by weight or less, even more preferably 60% by weight or less, particularly preferably 50% by weight or less, especially preferably Preferably it is 40% by weight or less, particularly preferably 30% by weight or less, and very preferably 20% by weight or less.

In a preferred embodiment of the present invention, the silicone-based graft copolymer is obtained by copolymerizing mixed monomers containing 0.1 to 2.5% by weight of carboxyl group-containing monomer (carboxylic acid-containing monomer) and 1 to 90% by weight of silicone macromonomer. It is desirable to be

The carboxyl group-containing monomer is the basis of the crosslinkable functional group of the silicone graft copolymer, and by mixing it in the above range, the silicone graft copolymer and the adhesive can be bonded through the crosslinking agent, thereby suppressing contamination of the adherend. You can. The silicone macromonomer provides the performance of a bleed agent to the silicone-based graft copolymer, and can reduce adhesion enhancement due to high temperature by blending it in an amount within the above range. In particular, by using a silicone-based graft copolymer formed by copolymerizing the adhesive, the crosslinking agent, and the mixed monomer, increased adhesion due to high temperature can be further reduced, and contamination of the adherend can be suppressed. In addition, in order to adjust the logarithmic contact angle after heating to the above range, the content of the carboxyl group-containing monomer is particularly important. If the carboxyl group-containing monomer is 0.1% by weight or more, the resulting silicone-based graft copolymer can sufficiently bond with the adhesive. If the carboxyl group-containing monomer is 2.5% by weight or less, the carboxyl groups not used for bonding with the adhesive can be reduced to prevent the surface of the adhesive layer from becoming hydrophilic, so it is easy to adjust the logarithmic contact angle after heating to the above range, thereby enhancing adhesion. can be reduced. From the above viewpoint, the more preferable lower limit of the content of the carboxyl group-containing monomer is 1.0 wt%, the more preferable lower limit is 1.5 wt%, the more preferable upper limit is 2.0 wt%, and the more preferable upper limit is 1.7 wt%. Moreover, from the viewpoint of further reducing adhesion enhancement by keeping the logarithmic contact angle after heating within the above range, a more preferable lower limit of the content of the silicone macromonomer is 2% by weight. A more preferable lower limit of the content of the silicone macromonomer is 2.5 wt%, an even more preferable lower limit is 3 wt%, a particularly preferable lower limit is 3.5 wt%, a particularly preferable lower limit is 4 wt%, a very preferable lower limit is 4.5 wt%, and the most preferable lower limit is 4.5 wt%. The lower limit is 5% by weight. A more preferable upper limit of the content of the silicone macromonomer is 80 wt%, a more preferable upper limit is 60 wt%, a still more preferable upper limit is 50 wt%, a particularly preferable upper limit is 40 wt%, a particularly preferable upper limit is 30 wt%, very preferable. The upper limit is 25% by weight, and the most preferred upper limit is 20% by weight.

In a preferred embodiment of the present invention, the silicone-based graft copolymer may be formed by copolymerizing a mixed monomer containing (meth)acrylic acid ester in addition to a polar functional group-containing monomer and a silicone macromonomer.

The (meth)acrylic acid ester is not particularly limited and includes, for example, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, and tert-butyl. (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, isononyl (meth)acrylate, isomyristyl (meth)acrylate, (meth)acrylic acid alkyl esters such as stearyl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, benzyl (meth)acrylate, and 2-butoxyethyl (meth)acrylate. ester, 2-phenoxyethyl (meth)acrylate, glycidyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, polypropylene glycol mono(meth)acrylate, etc. These (meth)acrylic acid esters may be used individually, or two or more types may be used together.

When the mixed monomer contains (meth)acrylic acid ester, the content of (meth)acrylic acid ester is preferably 1% by weight or more, and preferably 99% by weight or less. The content of the (meth)acrylic acid ester is more preferably 5% by weight or more, further preferably 7.5% by weight or more, even more preferably 10% by weight or more, more preferably 95% by weight or less, even more preferably 95% by weight or less. Preferably it is 90% by weight or less, more preferably 80% by weight or less.

As the crosslinkable functional group of the silicone-based graft copolymer, the same crosslinkable functional group as that of the adhesive can be used. In addition, the crosslinkable functional group of the silicone-based graft copolymer may be the same as or different from the crosslinkable functional group of the adhesive.

The silicone macromonomer preferably has a weight average molecular weight of 500 or more, and more preferably 1000 or more.

When the weight average molecular weight of the silicone macromonomer is more than the above lower limit, the hydrophobic surface layer formed by the silicone-based graft copolymer becomes thick, and adhesion enhancement can be further reduced. From the same viewpoint, a more preferable upper limit of the weight average molecular weight of the silicone macromonomer is 50,000, and is usually 20,000 or less.

The silicone-based graft copolymer has an acid value of preferably 0.5 mgKOH/g or more, more preferably 1 mgKOH/g or more, from the viewpoint of suppressing contamination of the adherend and controlling initial adhesive strength and adhesive strength after heating. Preferably it is 3 mgKOH/g or more, particularly preferably 5 mgKOH/g or more, and most preferably 10 mgKOH/g or more. Moreover, the acid value is preferably 22 mgKOH/g or less, more preferably 20 mgKOH/g or less, and even more preferably 19 mgKOH/g or less.

The silicone macromonomer may be any monomer having a siloxane bond-containing group in the side chain, and examples include silicone group-containing acrylic monomers and siloxane bond-containing styrene monomers. Among them, acrylic monomers containing siloxane bonds are preferable because they have excellent heat resistance and weather resistance. Examples of the siloxane bond-containing acrylic monomer include monomers having structural formulas such as the following general formula (1) or (2).

[Formula 1]

Here, R represents a (meth)acryloyl group-containing functional group, and X and Y each independently represent an integer of 0 or more, usually 5000 or less, especially 500 or less.

The content of the silicone macromonomer in the raw material monomer of the silicone graft copolymer of the present invention is preferably 1% by weight or more and 90% by weight or less. When the content of the silicone macromonomer is within the above range, increased adhesion under high temperatures can be further suppressed. From the viewpoint of further suppressing increased adhesion at high temperatures, the more preferable lower limit of the content of the silicone macromonomer is 5 wt%, the more preferable lower limit is 10 wt%, the more preferable upper limit is 80 wt%, and the more preferable upper limit is 60 wt%. .

Monomers other than the carboxyl group-containing monomer and the silicone macromonomer include, for example, (meth)acrylic acid ester. Additionally, acrylic monomers having other polar functional groups such as hydroxyl group, amino group, amide group, and nitrile group can also be used. Additionally, in addition to the acrylic monomer, a vinyl compound may be used as a monomer.

The silicone-based graft copolymer preferably has a weight average molecular weight of 400,000 or less.

If the polymerization average molecular weight of the silicone-based graft copolymer is 400,000 or less, the silicone-based graft copolymer becomes easy to move within the adhesive layer, so the silicone-based graft copolymer tends to gather on the adhesive layer surface, and adhesion enhancement can be further reduced. A more preferable upper limit of the polymerization average molecular weight of the silicone-based graft copolymer is 300,000, a further more preferable upper limit is 250,000, a particularly preferable upper limit is 200,000, and usually 10,000 or more.

The content of the silicone graft copolymer is preferably 0.1 to 30 parts by weight based on 100 parts by weight of the adhesive.

When the content of the silicone graft copolymer is 0.1 part by weight or more, increased adhesion can be further reduced. When the content of the silicone-based graft copolymer is 30 parts by weight or less, the silicone-based graft copolymer can sufficiently bond with the adhesive, and contamination of the adherend can be further suppressed. From the same viewpoint, the more preferable lower limit of the content of the silicone graft copolymer per 100 parts by weight of the adhesive is 0.5 parts by weight, the more preferable lower limit is 1 part by weight, the more preferable upper limit is 10 parts by weight, and the more preferable upper limit is 5 parts by weight. .

The crosslinking agent may be appropriately selected from one that can bind to the crosslinkable functional group of the adhesive and the silicone-based graft copolymer. Examples of the crosslinking agent include an epoxy-based crosslinking agent and an isocyanate-based crosslinking agent. Among them, an epoxy-based crosslinking agent is preferable because it is easy to adjust the shear storage modulus to the range described above.

The content of the cross-linking agent per 100 parts by weight of the adhesive has a preferable lower limit of 0.5 parts by weight, a more preferable lower limit of 1 part by weight, a preferable upper limit of 5 parts by weight, and a more preferable upper limit of 3 parts by weight. When the content of the crosslinking agent is in the above range, the adhesive and the silicone-based graft copolymer can be sufficiently crosslinked, and the logarithmic contact angle after heating and the shear storage modulus can be easily adjusted to the above range.

The adhesive layer may contain known additives such as inorganic fillers such as fumed silica, plasticizers, resins, surfactants, waxes, particulate fillers, antioxidants, and gas generating agents.

The thickness of the adhesive layer is not particularly limited, but the lower limit is preferably 5 μm and the upper limit is 100 μm. If the thickness of the adhesive layer is within the above range, it can be affixed to an adherend with sufficient adhesive force, and the residue of glue upon peeling can also be suppressed. A more preferable lower limit of the thickness of the adhesive layer is 10 μm, and a more preferable upper limit is 60 μm.

The method for manufacturing the adhesive tape that is one embodiment of the present invention is not particularly limited, and conventionally known methods can be used. For example, it can be manufactured by coating and drying the solution of the adhesive component on a film that has undergone release treatment.

The use of the adhesive tape of one embodiment of the present invention is not particularly limited, but examples include the manufacture of electronic components such as semiconductor chips and display devices (OLED, liquid crystal display devices, etc.), where adhesion by high temperature Since it can reduce vibration and can be applied to opaque materials, it can be particularly preferably used as a protective tape in the manufacture of electronic components such as semiconductor chips.

In another embodiment of the present invention, use of the adhesive tape in manufacturing electronic components is also provided. Particularly in the manufacture of electronic components using opaque materials, such as semiconductor chips, the adhesive tape can be advantageously used as a protective tape.

According to the present invention, it is possible to provide an adhesive tape that can reduce adhesion due to high temperature and can also be used for materials that do not transmit light.

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

(Synthesis of adhesive A)

6.38 g (50 mmol) of Tellurium (40 mesh, metal tellurium, manufactured by Aldrich) was suspended in 50 ml of tetrahydrofuran (THF), and a 1.6 mol/L n-butyllithium/hexane solution (Aldrich) was added thereto. (manufactured) 34.4 mL (55 mmol) was slowly added dropwise at room temperature. This reaction solution was stirred until the metal tellurium was completely disappeared. To this reaction solution, 10.7 g (55 mmol) of ethyl-2-bromo-isobutylate was added at room temperature, and the mixture was stirred for 2 hours. After completion of the reaction, the solvent was concentrated under reduced pressure and distilled under reduced pressure to obtain 2-methyl-2-n-butyltellanyl-ethyl propionate as a yellow oil.

In an argon-substituted glove box, in the reaction vessel, 19 ㎕ of the obtained 2-methyl-2-n-butyltellanyl-ethyl propionate, V-60 (2,2'-azobisisobutyronitrile, Fuji Film Wako) After adding 34 mg (manufactured by Pharmacist) and 1 ml of ethyl acetate, the reaction vessel was sealed and the reaction vessel was taken out from the glove box. Subsequently, while flowing argon gas into the reaction vessel, a total of 100 g of the mixed monomers shown in Table 1 and 66.5 g of ethyl acetate as a polymerization solvent were added into the reaction vessel, and a polymerization reaction was performed at 60°C for 20 hours. A solution containing a radically polymerized acrylic polymer (adhesive A) was obtained.

Next, the obtained solution containing adhesive A was diluted 50-fold with tetrahydrofuran (THF). The obtained dilution was filtered through a filter, the filtrate was supplied to a gel permeation chromatograph, GPC measurement was performed under the conditions of a sample flow rate of 1 milliliter/min and a column temperature of 40°C, and the polystyrene equivalent molecular weight of adhesive A was measured, The weight average molecular weight (Mw) and molecular weight distribution (Mw/Mn) were determined. In addition, the gel permeation chromatograph used was the 2690 Separations Model manufactured by Waters. The filter was made of polytetrafluoroethylene and had a pore diameter of 0.2 μm. GPC KF-806L (manufactured by Showa Denko) was used as a column, and a differential refractometer was used as a detector.

(Synthesis of adhesives B, C, F)

Solutions containing adhesives B, C, and F were obtained in the same manner as the synthesis of adhesive A except that the composition of the mixed monomer was as shown in Table 1, and the weight average molecular weight (Mw) and molecular weight distribution (Mw/Mn) were determined.

(Synthesis of adhesive D)

Prepare a reactor equipped with a thermometer, a stirrer, and a cooling tube, and add 100 parts by weight of 2-ethylhexyl acrylate, 3 parts by weight of acrylic acid, 0.1 part by weight of hydroxyethyl acrylate, and 80 parts by weight of ethyl acetate as monomers into the reactor. did. The reactor was heated to initiate reflux. Subsequently, 0.01 part by weight of V-60 (2,2'-azobisisobutyronitrile, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added as a polymerization initiator into the reactor, and a polymerization reaction was performed at 60° C. for 8 hours. An ethyl acetate solution of adhesive D was obtained. In the same manner as the synthesis of adhesive A, the weight average molecular weight (Mw) and molecular weight distribution (Mw/Mn) were determined.

(Synthesis of adhesives E and G)

Ethyl acetate solutions of adhesives E and G were obtained in the same manner as the synthesis of adhesive C except that the monomer composition was as shown in Table 1, and the weight average molecular weight (Mw) and molecular weight distribution (Mw/Mn) were determined.

(Synthesis of Bleed Agent A)

A reactor equipped with a thermometer, stirrer, and cooling tube was prepared. In this reactor, 39.9 parts by weight of 2-ethylhexyl acrylate as a monomer, 60 parts by weight of silicone macromonomer (KF-2012, methacryloyl-modified silicone, weight average molecular weight 4600, manufactured by Shin-Etsu Chemical Co., Ltd.), 0.1 part by weight of acrylic acid, n -0.2 parts by weight of dodecanethiol and 80 parts by weight of ethyl acetate were added. The reactor was heated to initiate reflux. Subsequently, 0.1 part by weight of 2,2'-azobisisobutyronitrile (V-60, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) as a polymerization initiator was added into the reactor, and polymerization was initiated under reflux. Next, 1 hour after the start of polymerization, 0.1 part by weight of 2,2'-azobisisobutyronitrile (V-60, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added, and further 6 hours after the start of polymerization, 2 , 0.2 parts by weight of 2'-azobisisobutyronitrile (V-60, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added to continue the polymerization reaction. Then, 7 hours after the start of polymerization, an ethyl acetate solution of bleed agent A, a silicone-based graft copolymer, was obtained. In the same manner as the synthesis of adhesive A, the weight average molecular weight (Mw) and molecular weight distribution (Mw/Mn) were determined. In addition, the acid value was calculated from the amount of monomer injected. Additionally, the glass transition temperature (Tg) of the bleed agent A was determined as a theoretical calculated value obtained by the following FOX equation.

1/Tg = W1/Tg1 + W2/Tg2 + ··· + Wn/Tgn

(Wherein, Tg is the glass transition temperature (K) of the bleed agent A, W1, W2,..., Wn are the weight fraction of each monomer, and Tg1, Tg2,..., Tgn are the weight fractions of each monomer. is the glass transition temperature of the homopolymer). The glass transition temperature of the homopolymer used in the above calculation can be a value described in the literature.

(Synthesis of bleed agent B to X)

Except that the monomer composition was as shown in Tables 2 and 3, the same procedure as the synthesis of bleed agent A was performed to obtain ethyl acetate solutions of bleed agents B to Mn) was obtained.

(Example 1)

To the obtained solution containing the adhesive A, ethyl acetate was added and stirred based on 100 parts by weight of the non-volatile content, and bleed agent A and an epoxy-based crosslinking agent were added and stirred in the types and mixing amounts shown in Table 4 to obtain a solution containing 30 weight percent of the non-volatile content. An ethyl acetate solution of the adhesive composition was obtained.

The ethyl acetate solution of the obtained adhesive composition was applied with a doctor knife on the corona-treated side of a 50-μm-thick transparent polyethylene naphthalate film that had been corona-treated on one side so that the dry film had a thickness of 40 μm, and heated at 110°C for 5 days. The coating solution was dried by heating for a minute. After that, static curing was performed at 40°C for 3 days to obtain an adhesive tape. Additionally, as an epoxy-based crosslinking agent, Tetrad C manufactured by Mitsubishi Gas Chemical Co., Ltd. was used.

(Measurement of logarithmic contact angle at 25°C)

In accordance with JIS R 3257:1999, the logarithmic contact angle was measured using a contact angle measuring device (CAM 200, manufactured by KSV).

Specifically, the adhesive tape was cut to a width of 25 mm and used for measurement. 2 µl of water droplets (ultrapure water) were dropped on the surface of the adhesive layer of an adhesive tape placed horizontally in an environment of room temperature 25°C and humidity 40%. The angle formed between pure water and the surface of the adhesive layer 5 seconds after dropping was taken as the logarithmic contact angle.

(Measurement of logarithmic contact angle after heating)

The adhesive tape was cut to a width of 25 mm. Press the cut adhesive tape onto a glass adherend (Matsunami Glass Industry Co., Ltd., large slide glass back-polished No. 2) at a room temperature of 23°C and a relative humidity of 50%, using a 2 kg rubber roller at a speed of 10 mm/sec. It was attached with . Next, heat treatment at 220°C for 120 minutes was performed once. After standing to cool, the adhesive tape was peeled off from the glass adherend, and the logarithmic contact angle was measured using a contact angle measuring device (CAM 200, manufactured by KSV) in accordance with JIS R 3257:1999.

Specifically, 2 µl of water droplets (ultrapure water) were dropped on the surface of the adhesive layer of an adhesive tape placed horizontally in an environment of room temperature 25°C and humidity 40%. The angle formed between pure water and the surface of the adhesive layer 5 seconds after dropping was taken as the logarithmic contact angle.

(Measurement of shear storage modulus)

Using a dynamic viscoelasticity measurement device (DVA-200, manufactured by IT Instrumentation Control Co., Ltd.), measurements were made from -50°C to 200°C in the shear mode of dynamic viscoelasticity measurement, with an angular frequency of 10 Hz and a temperature increase rate of 5°C/min, and the results were obtained. Among the measured values, the value of storage elastic modulus at 25°C was measured.

(Examples 2 to 25, Comparative Examples 1 to 12)

An adhesive tape was manufactured in the same manner as in Example 1 except that the types and mixing amounts of the adhesive, bleed agent, and crosslinking agent used were as shown in Tables 4 to 6, and the logarithmic contact angle before heating, the logarithmic contact angle after heating, and the shear storage modulus were measured. did. Additionally, Colonate L manufactured by Tosoh Corporation was used as an isocyanate-based crosslinking agent. As the epoxy-modified silicone, X-22-163C manufactured by Shin-Etsu Chemical Co., Ltd. was used. Additionally, as the isocyanate-based crosslinking agent, Colonate L45 manufactured by Nippon Polyurethane Industries, Ltd. was used.

＜Evaluation＞

The adhesive tapes obtained in Examples and Comparative Examples were evaluated by the following method. The results are shown in Tables 4 to 6.

(Evaluation of initial adhesion)

The adhesive tape was cut to a width of 25 mm. The cut adhesive tape is applied to a glass adherend (manufactured by Matsunami Glass Industry Co., Ltd., large slide glass back-polished No. 2) at a room temperature of 23°C and a relative humidity of 50%, using a 2 kg compression rubber roller at a speed of 10 mm/sec. It was attached at speed. After leaving for 30 minutes, the surface protection film was peeled at a speed of 300 mm/min in accordance with JIS Z 0237, the 180-degree peel strength was measured, and this was used as the initial adhesive strength.

(Evaluation of adhesion after heating)

The adhesive tape was cut to a width of 25 mm. The cut adhesive tape is applied to a glass adherend (manufactured by Matsunami Glass Industry Co., Ltd., large slide glass back-polished No. 2) at a room temperature of 23°C and a relative humidity of 50%, using a 2 kg compression rubber roller at a speed of 10 mm/sec. It was attached at speed. Next, heat treatment at 220°C for 120 minutes was performed once. After standing to cool, the surface protection film was peeled at a speed of 300 mm/min in accordance with JIS Z 0237, the 180-degree peel strength was measured, and this was used as the adhesive force after heating.

(Evaluation of contamination)

The glass plate after measuring the adhesion after heating was observed with the naked eye, and the residue was evaluated based on the following criteria.

A: No residue

B: There is residue in some parts (the area occupied by the area with residue is 10% or less)

C: There is residue on the entire surface (the area occupied by the area with residue exceeds 10%)

Industrial applicability

According to the present invention, it is possible to provide an adhesive tape that can reduce adhesion due to high temperature and can also be used for materials that do not transmit light.

Claims (11)

An adhesive tape having an adhesive layer,
The adhesive layer has a shear storage modulus of 4.0 × 10 ⁴ to 2.0 × 10 ⁶ Pa at 25°C, as evaluated by dynamic viscoelasticity measurement,
The adhesive layer has a logarithmic contact angle of 80° or more after attaching the adhesive layer side of the adhesive tape to glass, heating at 220° C. for 120 minutes, and peeling,
An adhesive tape in which the adhesive layer contains a silicone-based graft copolymer. According to claim 1,
The adhesive layer has a logarithmic contact angle of 110° or less after attaching the adhesive layer side of the adhesive tape to glass, heating it at 220°C, and peeling it off. The method of claim 1 or 2,
An adhesive tape wherein the adhesive layer has a logarithmic contact angle of 103° or less at 25°C. The method of claim 1 or 2,
The adhesive constituting the adhesive layer is an adhesive tape that is a non-curing adhesive. The method of claim 1 or 2,
The adhesive layer further contains an adhesive having a crosslinkable functional group, and a crosslinking agent capable of reacting with the adhesive and the silicone-based graft copolymer to crosslink the adhesive. The method of claim 1 or 2,
The silicone-based graft copolymer is an adhesive tape having an acid value of 0.5 mgKOH/g or more and 20 mgKOH/g or less. The method of claim 1 or 2,
The silicone-based graft copolymer is obtained by copolymerizing mixed monomers containing 0.1 to 2.5% by weight of carboxyl group-containing monomer and 1 to 90% by weight of silicone macromonomer, and has a weight average molecular weight of 400,000 or less. According to claim 5,
The crosslinking agent is an epoxy-based crosslinking agent, an adhesive tape. The method of claim 1 or 2,
An adhesive tape in which the content of the silicone-based graft copolymer is 0.1 to 30 parts by weight based on 100 parts by weight of the adhesive. According to claim 5,
The adhesive tape is an acrylic polymer with a molecular weight distribution (Mw/Mn) of 1.05 to 2.5. The method of claim 1 or 2,
The adhesive tape is an adhesive tape used in the manufacture of electronic components.