JP7117411B2 - Adhesive tape - Google Patents

Description

The present invention relates to adhesive tapes.

2. Description of the Related Art Conventionally, adhesive tapes have been widely used to fix components in electronic devices. Specifically, for example, an adhesive tape is used to adhere a cover panel for protecting the surface of a portable electronic device to a touch panel module or a display panel module, or to adhere a touch panel module and a display panel module. ing. In addition to high adhesiveness, adhesive tapes used for fixing such electronic device parts are required to have functions such as heat resistance, thermal conductivity, impact resistance, etc. depending on the environment of the site where they are used (for example, , Patent Documents 1 to 3).

BACKGROUND ART In recent years, electronic devices such as mobile phones, smart phones, wearable terminals, and the like, which are always worn or kept at hand, have become widespread due to the miniaturization, weight reduction, and cost reduction of electronic devices. Such portable electronic devices often come into contact with disinfectants, cleaning solutions, alcoholic beverages, etc., which are used on a daily basis. Even if it adheres to the tape, it is desired to have a performance that is not deteriorated by alcohol contained in antiseptic solution or the like.

JP 2015-052050 A JP 2015-021067 A JP 2015-120876 A

SUMMARY OF THE INVENTION An object of the present invention is to provide a pressure-sensitive adhesive tape that has excellent alcohol resistance and can maintain its adhesive strength even when a disinfectant, cleaning liquid, alcoholic beverage, or the like adheres to it.

The present invention is a pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer on at least one surface, wherein the pressure-sensitive adhesive layer comprises an acrylic copolymer and 0.1 to 5 parts by weight per 100 parts by weight of the acrylic copolymer. Containing a silane coupling agent, the acrylic copolymer contains 50% by weight or more of structural units derived from a monomer having an alkyl group having 6 or more carbon atoms, and a hydroxyl group, a carboxyl group, an amino group and an epoxy group. The polar functional group value of at least one polar functional group selected from the group consisting of is 0.01 to 5, and the pressure-sensitive adhesive layer contains 80% by weight of isopropanol and water under conditions of 60° C. and 90% humidity. It is an adhesive tape having a swelling rate of 100% by weight or more and 150% by weight or less after being immersed in a mixed solution of 20% by weight for 24 hours (also referred to as "adhesive tape of the first present invention").

The present invention also provides a pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer on at least one surface, wherein the pressure-sensitive adhesive layer comprises an acrylic copolymer and 0.1 to 5 parts by weight per 100 parts by weight of the acrylic copolymer. part of the silane coupling agent, the acrylic copolymer contains 10% by weight or more of structural units derived from a nitrile group-containing monomer, and is selected from the group consisting of a hydroxyl group, a carboxyl group, an amino group, and an epoxy group. The selected at least one polar functional group has a polar functional group value of 0.01 to 5, and the pressure-sensitive adhesive layer is formed from 80% by weight of isopropanol and 20% by weight of water under the conditions of 60° C. and 90% humidity. (also referred to as "adhesive tape of the second invention") having a swelling rate of 100% by weight or more and 150% by weight or less after being immersed in a mixed solution of (1) for 24 hours.

The present invention also provides a pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer on at least one surface, wherein the pressure-sensitive adhesive layer comprises an acrylic copolymer and 0.1 to 5 parts by weight per 100 parts by weight of the acrylic copolymer. part of the silane coupling agent, the acrylic copolymer contains 30% by weight or more of structural units derived from a fluorine-containing monomer, and is selected from the group consisting of a hydroxyl group, a carboxyl group, an amino group, and an epoxy group. The polar functional group value of at least one polar functional group is 0.01 to 5, and the pressure-sensitive adhesive layer is formed by mixing 80% by weight of isopropanol and 20% by weight of water under conditions of 60° C. and 90% humidity. The adhesive tape has a swelling rate of 100% by weight or more and 150% by weight or less after being immersed in the mixed solution for 24 hours (also referred to as "the adhesive tape of the third aspect of the present invention").

The present invention also provides a pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer on at least one surface, wherein the pressure-sensitive adhesive layer comprises an acrylic copolymer and 0.1 to 5 parts by weight per 100 parts by weight of the acrylic copolymer. part of the silane coupling agent, the acrylic copolymer contains 50% by weight or more of structural units derived from a cyclic structure-containing monomer, and is selected from the group consisting of a hydroxyl group, a carboxyl group, an amino group, and an epoxy group. The selected at least one polar functional group has a polar functional group value of 0.01 to 5, and the pressure-sensitive adhesive layer is formed from 80% by weight of isopropanol and 20% by weight of water under the conditions of 60° C. and 90% humidity. (also referred to as "adhesive tape of the fourth invention") having a swelling rate of 100% by weight or more and 150% by weight or less after being immersed in a mixed solution of (1) for 24 hours.
The present invention will be described in detail below.

The present inventors have found that in a pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer on at least one surface, a specific acrylic copolymer and a silane coupling agent are used in combination to form a pressure-sensitive adhesive layer, and the pressure-sensitive adhesive layer A study was made on adjusting the swelling ratio to a specific range after immersion in a mixed solution of 80% by weight isopropanol and 20% by weight water for 24 hours at 60° C. and 90% humidity. As a result, the present inventors have found that by using such an adhesive layer, the alcohol resistance of the adhesive tape is increased, and the adhesive strength is increased even when disinfectants, cleaning solutions, alcoholic beverages, etc. adhere to the adhesive tape. The present inventors have found that it can be maintained, and have completed the present invention.
The term "alcohol" as used herein means a single component of a lower alcohol having 4 or less carbon atoms or a mixture thereof. As long as the main component is a lower alcohol having 4 or less carbon atoms or a mixture thereof (the content is 50% by weight or more), it may contain other solvents such as water and alcohols with a higher number of carbon atoms, additives, and the like.

The first pressure-sensitive adhesive tape of the present invention has a pressure-sensitive adhesive layer on at least one surface.
In the pressure-sensitive adhesive tape of the first invention, the pressure-sensitive adhesive layer contains an acrylic copolymer and 0.1 to 5 parts by weight of a silane coupling agent per 100 parts by weight of the acrylic copolymer.

In the pressure-sensitive adhesive tape of the first invention, the acrylic copolymer contains 50% by weight or more of structural units derived from a monomer having an alkyl group having 6 or more carbon atoms, and has a hydroxyl group, a carboxyl group, an amino group and The polar functional group value of at least one polar functional group selected from the group consisting of epoxy groups is 0.01-5.
Such an acrylic copolymer has a low swelling rate with respect to alcohol. Therefore, by forming an adhesive layer using the above acrylic copolymer and a silane coupling agent in combination, the alcohol resistance of the adhesive tape is increased, and disinfectant, cleaning liquid, alcoholic beverages, etc. adhere to the adhesive tape. Adhesive strength can be maintained even in such cases.

When the content of the structural unit derived from the monomer having an alkyl group having 6 or more carbon atoms is 50% by weight or more, the polarity of the acrylic copolymer becomes low, and penetration into the molecular chain of the acrylic copolymer. Infiltration of alcohol is suppressed. For this reason, the swelling ratio of the acrylic copolymer to alcohol is lowered, and the alcohol resistance of the pressure-sensitive adhesive tape is improved. A preferable lower limit of the above content is 60% by weight, and a more preferable lower limit is 70% by weight.
Although the upper limit of the content of structural units derived from the monomer having an alkyl group having 6 or more carbon atoms is not particularly limited, the preferred upper limit is 99% by weight. If the content of the structural unit derived from the monomer having an alkyl group having 6 or more carbon atoms is 99% by weight or less, the pressure-sensitive adhesive layer does not become too soft, and sufficient cohesive force can be maintained. The tape can exhibit sufficient adhesive strength. A more preferable upper limit of the above content is 97% by weight.

The monomer having an alkyl group having 6 or more carbon atoms is not particularly limited, and examples thereof include 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, isostearyl (meth) acrylate, hexyl (meth) Acrylate, heptyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate and the like. Among them, 2-ethylhexyl (meth)acrylate or octyl (meth)acrylate is preferable because it can exhibit suitable adhesive strength. These monomers having an alkyl group having 6 or more carbon atoms may be used alone or in combination.
In this specification, (meth)acrylate means acrylate or methacrylate, and (meth)acrylonitrile means acrylonitrile or methacrylonitrile.

The pressure-sensitive adhesive tape of the second invention has a pressure-sensitive adhesive layer on at least one surface.
In the pressure-sensitive adhesive tape of the second invention, the pressure-sensitive adhesive layer contains an acrylic copolymer and 0.1 to 5 parts by weight of a silane coupling agent per 100 parts by weight of the acrylic copolymer.

In the pressure-sensitive adhesive tape of the second aspect of the present invention, the acrylic copolymer contains 10% by weight or more of structural units derived from a nitrile group-containing monomer, and is selected from the group consisting of a hydroxyl group, a carboxyl group, an amino group, and an epoxy group. The polar functional group value of at least one selected polar functional group is 0.01-5.
Such an acrylic copolymer has a low swelling rate with respect to alcohol. Therefore, by forming an adhesive layer using the above acrylic copolymer and a silane coupling agent in combination, the alcohol resistance of the adhesive tape is increased, and disinfectant, cleaning liquid, alcoholic beverages, etc. adhere to the adhesive tape. Adhesive strength can be maintained even in such cases.

When the content of the structural unit derived from the nitrile group-containing monomer is 10% by weight or more, the cohesive force of the acrylic copolymer increases, and the penetration of alcohol into the molecular chain of the acrylic copolymer is suppressed. be done. For this reason, the swelling ratio of the acrylic copolymer to alcohol is lowered, and the alcohol resistance of the pressure-sensitive adhesive tape is improved. In addition, when the content of the structural unit derived from the nitrile group-containing monomer is 10% by weight or more, the cohesive force of the acrylic copolymer increases and the polarity becomes relatively high, and the molecules of the acrylic copolymer Intrusion of oleic acid into the chain is suppressed. For this reason, the swelling ratio of the acrylic copolymer to oleic acid is lowered, and the resistance of the pressure-sensitive adhesive tape to sebum (mainly composed of oleic acid) is improved. A preferable lower limit of the content is 13% by weight.
Although the upper limit of the content of structural units derived from the nitrile group-containing monomer is not particularly limited, the preferred upper limit is 20% by weight. When the content of structural units derived from the nitrile group-containing monomer is 20% by weight or less, the adhesive tape can exhibit sufficient adhesive strength. A more preferable upper limit of the above content is 17% by weight.

Examples of the nitrile group-containing monomer include (meth)acrylonitrile. Among them, acrylonitrile is preferable because it tends to exhibit adhesive strength. These nitrile group-containing monomers may be used alone or in combination.

The pressure-sensitive adhesive tape of the third invention has a pressure-sensitive adhesive layer on at least one surface.
In the pressure-sensitive adhesive tape of the third aspect of the present invention, the pressure-sensitive adhesive layer contains an acrylic copolymer and 0.1 to 5 parts by weight of a silane coupling agent per 100 parts by weight of the acrylic copolymer.

In the pressure-sensitive adhesive tape of the third aspect of the present invention, the acrylic copolymer contains 30% by weight or more of structural units derived from fluorine-containing monomers, and is selected from the group consisting of hydroxyl groups, carboxyl groups, amino groups and epoxy groups. The polar functional group value of at least one polar functional group is 0.01-5.
Such an acrylic copolymer has a low swelling rate with respect to alcohol. Therefore, by forming an adhesive layer using the above acrylic copolymer and a silane coupling agent in combination, the alcohol resistance of the adhesive tape is increased, and disinfectant, cleaning liquid, alcoholic beverages, etc. adhere to the adhesive tape. Adhesive strength can be maintained even in such cases.

When the content of structural units derived from the fluorine-containing monomer is 30% by weight or more, due to the high water and oil repellency of fluorine itself and the dense packing of fluorine atoms, of alcohol is suppressed. For this reason, the swelling ratio of the acrylic copolymer to alcohol is lowered, and the alcohol resistance of the pressure-sensitive adhesive tape is improved. A preferable lower limit of the content is 40% by weight, and a more preferable lower limit is 50% by weight.
Although the upper limit of the content of structural units derived from the fluorine-containing monomer is not particularly limited, the preferred upper limit is 80% by weight. When the content of structural units derived from the fluorine-containing monomer is 80% by weight or less, the pressure-sensitive adhesive layer does not become too hard, sufficient tackiness can be maintained, and the pressure-sensitive adhesive tape has sufficient adhesive strength. can demonstrate. A more preferable upper limit of the content is 60% by weight.

The fluorine-containing monomer is not particularly limited, and examples include 2,2,2-trifluoroethyl acrylate, 2-(perfluorohexyl)ethyl acrylate, 2,2,3,3,3-pentafluoropropyl acrylate, 2- (perfluorobutyl) ethyl acrylate, 3-perfluorobutyl-2-hydroxypropyl acrylate, 3-perfluorohexyl-2-hydroxypropyl acrylate, 3-(perfluoro-3-methylbutyl)-2-hydroxypropyl acrylate, 1H , 1H,3H-tetrafluoropropyl acrylate, 1H,1H,5H-octafluoropentyl acrylate, 1H,1H,7H-dodecafluoroheptyl acrylate, 1H-1-(trifluoromethyl)trifluoroethyl acrylate, 1H,1H, 3H-hexafluorobutyl acrylate, 1,2,2,2-tetrafluoro-1-(trifluoromethyl)ethyl acrylate and the like. Among them, 2,2,2-trifluoroethyl acrylate is preferred because of its high alcohol resistance. These fluorine-containing monomers may be used alone or in combination.

The adhesive tape of the fourth invention has an adhesive layer on at least one surface.
In the pressure-sensitive adhesive tape of the fourth aspect of the present invention, the pressure-sensitive adhesive layer contains an acrylic copolymer and 0.1 to 5 parts by weight of a silane coupling agent per 100 parts by weight of the acrylic copolymer.

In the pressure-sensitive adhesive tape of the fourth aspect of the present invention, the acrylic copolymer contains 50% by weight or more of structural units derived from a cyclic structure-containing monomer, and is selected from the group consisting of a hydroxyl group, a carboxyl group, an amino group, and an epoxy group. The polar functional group value of at least one selected polar functional group is 0.01-5.
Such an acrylic copolymer has a low swelling rate with respect to alcohol. Therefore, by forming an adhesive layer using the above acrylic copolymer and a silane coupling agent in combination, the alcohol resistance of the adhesive tape is increased, and disinfectant, cleaning liquid, alcoholic beverages, etc. adhere to the adhesive tape. Adhesive strength can be maintained even in such cases.

When the content of the structural unit derived from the cyclic structure-containing monomer is 50% by weight or more, the polarity of the acrylic copolymer becomes low, and the penetration of alcohol into the molecular chain of the acrylic copolymer is suppressed. . For this reason, the swelling ratio of the acrylic copolymer to alcohol is lowered, and the alcohol resistance of the pressure-sensitive adhesive tape is improved. A more preferable lower limit of the content is 55% by weight.
Although the upper limit of the content of structural units derived from the cyclic structure-containing monomer is not particularly limited, the preferred upper limit is 70% by weight. If the content of the structural unit derived from the cyclic structure-containing monomer is 70% by weight or less, the pressure-sensitive adhesive layer does not become too hard, sufficient tackiness can be maintained, and the pressure-sensitive adhesive tape has sufficient adhesive strength. can be demonstrated. A more preferable upper limit of the above content is 65% by weight.

The cyclic structure-containing monomer is not particularly limited, and examples thereof include cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, and the like. Among them, cyclohexyl acrylate is preferable because it tends to exhibit adhesive strength. These cyclic structure-containing monomers may be used alone or in combination.

Items common to the adhesive tapes of the first to fourth aspects of the present invention will be described below.
In the present specification, the polar functional group value of at least one polar functional group selected from the group consisting of a hydroxyl group, a carboxyl group, an amino group, and an epoxy group in the acrylic copolymer refers to the polar functional group in the acrylic copolymer. means the content of structural units derived from a monomer having When the monomer has a valence of 2 or more (the monomer has two or more of the polar functional groups), it means the content in terms of the monovalent polar functional group. The polar functional group does not include a polar functional group derived from the silane coupling agent.
In the pressure-sensitive adhesive tapes of the first to fourth aspects of the present invention, when the polar functional group value is 0.01 or more, the acrylic copolymer can have sufficient cohesive strength, and the pressure-sensitive adhesive tape has sufficient adhesive strength. can be demonstrated. When the polar functional group value is 5 or less, the polarity of the acrylic copolymer becomes low, and the penetration of alcohol into the molecular chain of the acrylic copolymer is suppressed. For this reason, the swelling ratio of the acrylic copolymer to alcohol is lowered, and the alcohol resistance of the pressure-sensitive adhesive tape is improved. The preferred lower limit of the polar functionality is 0.05, the preferred upper limit is 4, the more preferred lower limit is 0.1, and the more preferred upper limit is 3.

The polar functional group has reactivity such as cross-linking reaction, and is at least one selected from the group consisting of a hydroxyl group, a carboxyl group, an amino group and an epoxy group. Among them, a hydroxyl group or a carboxyl group is preferable because it can contribute to improvement in adhesive strength.
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. Examples of the monomer having a carboxyl group include (meth)acrylic acid. Examples of the epoxy group-containing monomer include glycidyl (meth)acrylate. These polar functional group-containing monomers may be used alone or in combination.

In the pressure-sensitive adhesive tapes of the first to fourth aspects of the present invention, the acrylic copolymer further includes ethyl acrylate, propyl acrylate, butyl acrylate, benzyl acrylate, phenoxyethyl acrylate, vinyl acetate, as long as the effects of the present invention are not impaired. and the like may contain structural units derived from.

The weight-average molecular weight of the acrylic copolymer has a preferred lower limit of 500,000 and a preferred upper limit of 2,000,000. When the weight average molecular weight of the acrylic copolymer is within the above range, the adhesive strength of the pressure-sensitive adhesive tape is improved. A more preferable lower limit of the weight average molecular weight of the acrylic copolymer is 700,000, and a more preferable upper limit thereof is 1,500,000.
The weight-average molecular weight can be adjusted by polymerization conditions (eg, type or amount of polymerization initiator, polymerization temperature, monomer concentration, etc.).

In order to synthesize the above acrylic copolymer, the acrylic monomer from which the above structural unit is derived may be radically reacted in the presence of a polymerization initiator. The polymerization method is not particularly limited, and conventionally known methods can be used. Examples thereof include solution polymerization (boiling point polymerization or constant temperature polymerization), emulsion polymerization, suspension polymerization, bulk polymerization and the like. Among them, solution polymerization is preferable because of its simple synthesis. Emulsion polymerization is preferred particularly when the content of structural units derived from acrylonitrile is increased.

When solution polymerization is used as the polymerization method, examples of reaction solvents include ethyl acetate, toluene, methyl ethyl ketone, methyl sulfoxide, ethanol, acetone, and diethyl ether. These reaction solvents may be used alone or in combination.

The polymerization initiator is not particularly limited, and examples thereof include organic peroxides and azo compounds. Examples of the organic peroxide include 1,1-bis(t-hexylperoxy)-3,3,5-trimethylcyclohexane, t-hexylperoxypivalate, t-butylperoxypivalate, 2,5 -dimethyl-2,5-bis(2-ethylhexanoylperoxy)hexane, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, t-butylperoxy isobutyrate, t-butylperoxy-3,5,5-trimethylhexanoate, t-butylperoxylaurate and the like. Examples of the azo compound include azobisisobutyronitrile and azobiscyclohexanecarbonitrile. These polymerization initiators may be used alone or in combination.

In the pressure-sensitive adhesive tapes of the first to fourth aspects of the present invention, the pressure-sensitive adhesive layer contains 0.1-5 parts by weight of a silane coupling agent with respect to 100 parts by weight of the acrylic copolymer.
By adding a silane coupling agent to the pressure-sensitive adhesive layer, the adhesive strength at the interface between the pressure-sensitive adhesive tape and the adherend can be increased. For this reason, by forming an adhesive layer using both an acrylic copolymer having a low swelling rate with respect to alcohol as described above and a silane coupling agent, the alcohol resistance of the adhesive tape is increased, and disinfectant, cleaning liquid, Adhesion can be maintained even when alcoholic beverages or the like adhere to the adhesive tape.

The silane coupling agent is not particularly limited, and examples thereof include vinyltrimethoxysilane, vinyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, and 3-glycidoxypropyltrimethoxysilane. , 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-amino Propyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyltrimethylmethoxysilane, N-(2-aminoethyl)3-aminopropyltriethoxysilane, N-(2-aminoethyl)3-aminopropylmethyl dimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, mercaptobutyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane and the like. Among them, 3-glycidoxypropyltrimethoxysilane is preferred.

When the content of the silane coupling agent is 0.1 parts by weight or more, the adhesive strength at the interface between the adhesive tape and the adherend is increased, and the alcohol resistance of the adhesive tape is improved. When the content of the silane coupling agent is 5 parts by weight or less, adhesive residue can be suppressed when the adhesive tape is peeled off, and the reworkability of the adhesive tape is improved. The preferable lower limit of the content of the silane coupling agent is 0.5 parts by weight, the preferable upper limit is 4 parts by weight, the more preferable lower limit is 1 part by weight, and the more preferable upper limit is 3 parts by weight.

In the pressure-sensitive adhesive tapes of the first to fourth aspects of the present invention, the pressure-sensitive adhesive layer may optionally contain additives such as plasticizers, emulsifiers, softeners, fillers, pigments and dyes, rosin-based resins, and terpene-based resins. It may contain a tackifier such as, other resins, and the like.

In the pressure-sensitive adhesive tapes of the first to fourth aspects of the present invention, the pressure-sensitive adhesive layer preferably has a gel fraction of 10% by weight or more. If the gel fraction is 10% by weight or more, the pressure-sensitive adhesive layer after being immersed in a mixture of 80% by weight isopropanol and 20% by weight water for 24 hours under conditions of 60° C. and 90% humidity. It becomes easier to adjust the swelling rate to a specific range, and the alcohol resistance of the adhesive tape is improved. A more preferable lower limit of the gel fraction is 20% by weight.
Although the upper limit of the gel fraction is not particularly limited, a preferable upper limit is 99% by weight, and a more preferable upper limit is 95% by weight.
In addition, the "gel fraction" in this specification means the weight of the adhesive layer after being immersed in ethyl acetate and drying with respect to the weight of the adhesive layer before being immersed in ethyl acetate as shown in the following formula (1). is a value expressed as a percentage.
Gel fraction (% by weight) = 100 x (W2-W0)/(W1-W0) (1)
(W0: weight of base material, W1: weight of adhesive tape test piece before immersion in ethyl acetate, W2: weight of adhesive tape test piece after immersion in ethyl acetate and drying)

In the pressure-sensitive adhesive tapes of the first to fourth aspects of the present invention, the pressure-sensitive adhesive layer is immersed in a mixture of 80% by weight isopropanol and 20% by weight water for 24 hours under conditions of 60° C. and 90% humidity. The swelling rate (also referred to as "alcohol swelling rate") is 100% by weight or more and 150% by weight or less.
An acrylic copolymer having a low swelling rate with respect to alcohol as described above and a silane coupling agent are used in combination to form a pressure-sensitive adhesive layer, and the alcohol swelling rate of the pressure-sensitive adhesive tape is adjusted to the above range. The resistance is improved, and the adhesive strength can be maintained even when disinfectant, cleaning liquid, alcoholic beverages, etc. adhere to the adhesive tape.
In addition, the "alcohol swelling rate" in this specification refers to the weight of the pressure-sensitive adhesive layer before immersion in a mixture of 80% by weight of isopropanol and 20% by weight of water as shown in the following formula (2). It is a value expressed as a percentage of the weight ratio of the pressure-sensitive adhesive layer after being immersed in a mixed solution of 80% by weight of gel and 20% by weight of water and dried. When there is elution of the adhesive component into the mixed liquid, the alcohol swelling rate is less than 100% by weight.
Alcohol swelling rate (% by weight) = 100 x (W5-W3)/(W4-W3) (2)
(W3: Weight of base material, W4: Weight of pressure-sensitive adhesive tape test piece before immersion in mixed solution of 80% by weight of isopropanol and 20% by weight of water, W5: 80% by weight of isopropanol and 20% by weight of water Mixed solution immersion, weight of adhesive tape test piece after drying)

If the swelling rate of the pressure-sensitive adhesive layer after being immersed in the mixed solution for 24 hours at 60° C. and 90% humidity is 100% by weight or more, it means that there is no elution of the pressure-sensitive adhesive component into the mixed solution. and the alcohol resistance of the adhesive tape is improved. When the pressure-sensitive adhesive layer has a swelling rate of 150% by weight or less after being immersed in the mixed liquid for 24 hours under the conditions of 60° C. and 90% humidity, the alcohol resistance of the pressure-sensitive adhesive tape is improved. A preferable upper limit of the swelling rate is 140% by weight, and a more preferable upper limit is 130% by weight.

In the pressure-sensitive adhesive tapes of the first to fourth aspects of the present invention, the pressure-sensitive adhesive layer has a swelling rate (also referred to as "oleic acid swelling rate") after being immersed in oleic acid for 24 hours under conditions of 60° C. and 90% humidity. It is preferably 100% by weight or more and 115% by weight or less.
In addition, the "oleic acid swelling rate" in the present specification means the weight of the adhesive layer after being immersed in oleic acid with respect to the weight of the adhesive layer before being immersed in oleic acid, as shown in the following formula (3). It is a value that expresses the weight ratio as a percentage. When there is elution of the adhesive component into oleic acid, the oleic acid swelling ratio is below 100% by weight.
Oleic acid swelling rate (% by weight) = 100 x (W8-W6)/(W7-W6) (3)
(W6: weight of base material, W7: weight of adhesive tape test piece before immersion in oleic acid, W8: weight of adhesive tape test piece after immersion in oleic acid and drying)

If the swelling rate of the pressure-sensitive adhesive layer after being immersed in oleic acid for 24 hours at 60° C. and 90% humidity is 100% by weight or more, it means that there is no elution of the pressure-sensitive adhesive component into oleic acid. This improves the resistance of the adhesive tape to sebum. When the adhesive layer has a swelling ratio of 115% by weight or less after being immersed in oleic acid for 24 hours at 60° C. and 90% humidity, the adhesive tape has improved resistance to sebum. A more preferable upper limit of the swelling ratio is 110% by weight, and an even more preferable upper limit is 105% by weight.

In the pressure-sensitive adhesive tapes of the first to fourth aspects of the present invention, the thickness of the pressure-sensitive adhesive layer is not particularly limited, but the preferred lower limit is 5 μm and the preferred upper limit is 100 μm. When the thickness of the pressure-sensitive adhesive layer is 5 μm or more, the adhesive strength of the pressure-sensitive adhesive tape is improved. If the thickness of the pressure-sensitive adhesive layer is 100 µm or less, the workability of the pressure-sensitive adhesive tape is improved.

The pressure-sensitive adhesive tapes of the first to fourth aspects of the present invention may be a support type having a substrate or a non-support type having no substrate as long as they have the pressure-sensitive adhesive layer on at least one surface. can be a type. In the case of the support type, the pressure-sensitive adhesive layer may be formed on one side of the substrate, or the pressure-sensitive adhesive layer may be formed on both sides.

The substrate is not particularly limited, and examples thereof include polyolefin resin films such as polyethylene films and polypropylene films, polyester resin films such as PET films, and the like. Furthermore, ethylene-vinyl acetate copolymer films, polyvinyl chloride resin films, polyurethane resin films, polyethylene foam sheets, polyolefin foam sheets such as polypropylene foam sheets, polyurethane foam sheets, and the like are included. Among them, a PET film is preferable. Polyolefin foam sheets are preferred from the viewpoint of impact resistance.
Further, as the base material, a black printed base material for preventing light transmission, a white printed base material for improving light reflectivity, a metal deposited base material, or the like can be used.

The method for producing the pressure-sensitive adhesive tapes of the first to fourth aspects of the present invention is not particularly limited. For example, when the pressure-sensitive adhesive tapes of the first to fourth aspects of the present invention are double-sided pressure-sensitive adhesive tapes having a substrate, the following method is used. are mentioned.
First, a solvent is added to an acrylic copolymer, a silane coupling agent, and additives as necessary to prepare a solution of acrylic adhesive a, and this solution of acrylic adhesive a is applied to the surface of a base material. , the solvent in the solution is completely removed by drying to form an adhesive layer a. Next, a release film is overlaid on the formed pressure-sensitive adhesive layer a so that the release-treated surface faces the pressure-sensitive adhesive layer a.
Next, a release film different from the release film is prepared, a solution of the acrylic adhesive b is applied to the release-treated surface of the release film, and the solvent in the solution is completely removed by drying. A laminated film is prepared by forming a pressure-sensitive adhesive layer b on the surface of a release film. The laminated film thus obtained is placed on the back surface of the base material on which the pressure-sensitive adhesive layer a is formed so that the pressure-sensitive adhesive layer b faces the back surface of the base material to prepare a laminate. By pressing the laminate with a rubber roller or the like, a pressure-sensitive adhesive tape having pressure-sensitive adhesive layers on both sides of the base material and the surface of the pressure-sensitive adhesive layer covered with a release film can be obtained.

In addition, two sets of laminated films are prepared in the same manner, and these laminated films are laminated on both sides of the base material with the pressure-sensitive adhesive layer of the laminated film facing the base material to prepare a laminate. Alternatively, by pressing this laminate with a rubber roller or the like, a pressure-sensitive adhesive tape having pressure-sensitive adhesive layers on both sides of a base material and the surface of the pressure-sensitive adhesive layer covered with a release film may be obtained.

Applications of the adhesive tapes of the first to fourth aspects of the present invention are not particularly limited, but since they are excellent in alcohol resistance, they are parts of electronic devices that are often in contact with disinfectants, cleaning solutions, alcoholic beverages, etc. that are used on a daily basis. can be used particularly preferably for fixing. Specifically, the adhesive tapes of the first to fourth aspects of the present invention are used for fixing the touch panel portion of mobile electronic devices such as smartphones and tablet terminals, and fixing the display panel portion of in-vehicle electronic devices such as car navigation systems. can be preferably used.

The shape of the pressure-sensitive adhesive tapes of the first to fourth aspects of the present invention is not particularly limited, and may be rectangular or the like, or may be sheet-like. A frame shape is preferable because it is suitable for fixing the touch panel portion or the display panel portion as described above. Further, the pressure-sensitive adhesive tapes of the first to fourth aspects of the present invention may be of a support type having a substrate or may be of a non-support type having no substrate. In the case of the support type, the pressure-sensitive adhesive layer may be formed on one side of the substrate, or the pressure-sensitive adhesive layer may be formed on both sides. In addition, the adhesive tapes of the first to fourth aspects of the present invention are excellent in alcohol resistance, and can maintain adhesive strength even when disinfectants, cleaning solutions, alcoholic beverages, etc. adhere. can be preferably used, and can be particularly preferably used when the width of the adhesive tape is 5 mm or less.

ADVANTAGE OF THE INVENTION According to this invention, the adhesive tape which is excellent in alcohol resistance and can maintain adhesive force even when a disinfectant, a cleaning liquid, an alcoholic beverage, etc. adheres can be provided.

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

(Example 1)
(1) Production of acrylic copolymer Ethyl acetate was added as a polymerization solvent into a reaction vessel, and nitrogen was bubbled through the reaction vessel. Subsequently, a polymerization initiator solution obtained by diluting 0.1 parts by weight of azobisisobutyronitrile 10 times with ethyl acetate as a polymerization initiator was charged into the reaction vessel, and 68.5 parts by weight of 2-ethylhexyl acrylate and isostearyl were added. 28.5 parts by weight of acrylate and 3 parts by weight of acrylic acid were added dropwise over 2 hours. After the dropwise addition, a polymerization initiator solution prepared by diluting 0.1 part by weight of azobisisobutyronitrile 10 times with ethyl acetate as a polymerization initiator was put into the reaction vessel again, and the polymerization reaction was carried out for 4 hours, followed by acrylic copolymerization. A coalescing containing solution was obtained.

(2) Molecular weight measurement of acrylic copolymer Dilute the obtained acrylic copolymer 50 times with tetrahydrofuran (THF) and filter the diluted solution (material: polytetrafluoroethylene, pore diameter: 0.2 μm). to prepare a measurement sample. This measurement sample is supplied to a gel permeation chromatograph (manufactured by Waters, 2690 Separations Model), and GPC measurement is performed under the conditions of a sample flow rate of 1 ml / min and a column temperature of 40 ° C. to determine the polystyrene equivalent molecular weight of the acrylic copolymer. was measured to determine the weight average molecular weight (Mw). GPC LF-804 (manufactured by Showa Denko) was used as the column, and a differential refractometer was used as the detector.

(3) Production of Single-Sided Adhesive Tape To the acrylic copolymer-containing solution obtained, 3 parts by weight of 3-glycidoxypropyltrimethoxysilane as a silane coupling agent per 100 parts by weight of the acrylic copolymer, and a cross-linking agent were added. Tetrad C (manufactured by Mitsubishi Gas Chemical Co., Ltd.) was added in an amount of 0.3 parts by weight (percentage of solid components) to prepare an adhesive solution. After coating this adhesive solution on a release-treated PET film with a thickness of 75 μm so that the thickness of the adhesive layer after drying is 35 μm, it is dried at 110 ° C. for 5 minutes to form an adhesive layer. rice field. This pressure-sensitive adhesive layer was transferred to a corona-treated PET film having a thickness of 50 μm and cured at 40° C. for 48 hours to obtain a single-sided pressure-sensitive adhesive tape.

(4) Measurement of gel fraction The obtained single-sided adhesive tape was cut into a flat rectangular shape of 20 mm x 40 mm to prepare a test piece, and the weight was measured. After the test piece was immersed in ethyl acetate at 23°C for 24 hours, the test piece was removed from the ethyl acetate and dried at 110°C for 1 hour. The weight of the test piece after drying was measured, and the gel fraction was calculated using the following formula (1).
Gel fraction (% by weight) = 100 x (W2-W0)/(W1-W0) (1)
(W0: weight of base material, W1: weight of test piece before immersion in ethyl acetate, W2: weight of test piece after immersion in ethyl acetate and drying)

(5) Measurement of Alcohol Swelling Ratio The obtained single-sided adhesive tape was cut into a flat rectangular shape of 20 mm×40 mm to prepare a test piece, and the weight was measured. After immersing the test piece in a mixed solution of 80 wt% isopropanol and 20 wt% water at 60°C and 90% humidity for 24 hours, remove the test piece from the mixed solution and wash the surface with ethanol. After that, it was dried at 110° C. for 3 hours. The weight of the test piece after drying was measured, and the alcohol swelling rate was calculated using the following formula (2).
Alcohol swelling rate (% by weight) = 100 x (W5-W3)/(W4-W3) (2)
(W3: weight of base material, W4: weight of test piece before immersion in mixed solution of 80% by weight isopropanol and 20% by weight of water, W5: mixed solution of 80% by weight isopropanol and 20% by weight of water Weight of test piece after immersion and drying)

(Examples 2 to 7, Comparative Examples 1 to 7)
A single-sided adhesive tape was obtained in the same manner as in Example 1 except that the types and amounts of the monomers and silane coupling agents used were changed as shown in Table 1.

<Evaluation>
The single-sided pressure-sensitive adhesive tapes obtained in Examples and Comparative Examples were evaluated as follows. Table 1 shows the results.
(180° peeling adhesive strength after immersion in alcohol)
The obtained single-sided adhesive tape was cut into strips having a width of 5 mm to prepare test pieces, and the release film was peeled off to expose the adhesive layer. After placing this test piece on a stainless steel plate so that the adhesive layer faces the stainless plate, a rubber roller of 2 kg is reciprocated on the test piece at a speed of 300 mm / min. A plate was bonded together and then allowed to stand at 23° C. for 24 hours to prepare a test sample.
This test sample was immersed in a bath of a mixture of 80% by weight isopropanol and 20% by weight water at 60° C. and 90% humidity for 24 hours, taken out, washed with water, and allowed to stand for 24 hours.
After that, according to JIS Z0237, a tensile test in the 180° direction was performed at a peeling speed of 300 mm / min, and the 180° peeling adhesive strength (N/ 5 mm) was measured. When the 180° peeling adhesive strength was less than the measurement limit value of the equipment, it was defined as 0.
◎ when the 180 ° peeling adhesive strength (N / 5 mm) after immersion in the mixed solution was 1.0 N / 5 mm or more, ○ when it was 0.2 N / 5 mm or more and less than 1.0 N / 5 mm, 0 A case of less than 2 N/5 mm was marked as x.

For the single-sided adhesive tapes obtained in Examples 3 and 4, the oleic acid swelling rate was measured and the 180° peeling adhesive strength after immersion in oleic acid was evaluated as follows. Table 2 shows the results.

(Measurement of oleic acid swelling rate)
The obtained single-sided adhesive tape was cut into a flat rectangular shape of 20 mm×40 mm to prepare a test piece, and the weight was measured. After the test piece was immersed in oleic acid at 60° C. and humidity of 90% for 24 hours, the test piece was removed from the oleic acid, washed with ethanol, and dried at 110° C. for 3 hours. The weight of the test piece after drying was measured, and the oleic acid swelling rate was calculated using the following formula (3).
Oleic acid swelling rate (% by weight) = 100 x (W8-W6)/(W7-W6) (3)
(W6: weight of base material, W7: weight of test piece before immersion in oleic acid, W8: weight of test piece after immersion in oleic acid and drying)

(180° peeling adhesive strength after immersion in oleic acid)
A test sample was prepared in the same manner as for the 180° peeling adhesive strength after alcohol immersion.
This test sample was immersed in an oleic acid bath at 60° C. and a humidity of 90% for 24 hours, taken out, washed with water, and allowed to stand for 24 hours.
Thereafter, according to JIS Z0237, a tensile test in the 180° direction was performed at a peel rate of 300 mm/min, and the 180° peeling adhesive strength (N/5 mm) after immersion in oleic acid was measured. When the 180° peeling adhesive strength was less than the measurement limit value of the equipment, it was defined as 0.
◎ when the 180 ° peeling adhesive strength (N / 5 mm) after immersion in oleic acid was 1.0 N / 5 mm or more, ○ when it was more than 0.15 N / 5 mm and less than 1.0 N / 5 mm , 0.15 N/5 mm or less was evaluated as x.

ADVANTAGE OF THE INVENTION According to this invention, the adhesive tape which is excellent in alcohol resistance and can maintain adhesive force even when a disinfectant, a cleaning liquid, an alcoholic beverage, etc. adheres can be provided.

Claims (6)

An adhesive tape having an adhesive layer on at least one surface,
The pressure-sensitive adhesive layer is an acrylic copolymer and 0.00 parts per 100 parts by weight of the acrylic copolymer.
Contains 1 to 5 parts by weight of a silane coupling agent,
The acrylic copolymer contains 30% by weight or more of structural units derived from a fluorine-containing monomer, and has at least one polar functional group selected from the group consisting of a hydroxyl group, a carboxyl group, an amino group, and an epoxy group. Containing structural units derived from monomers,
The product of the number of parts by weight of the structural unit with respect to 100 parts by weight of the acrylic copolymer and the number of the polar functional groups per molecule of the monomer is 0.01 to 5,
The pressure-sensitive adhesive layer has a swelling rate of 100% by weight or more and 150% by weight or less after being immersed in a mixture of 80% by weight of isopropanol and 20% by weight of water for 24 hours under conditions of 60° C. and 90% humidity. An adhesive tape characterized by: An adhesive tape having an adhesive layer on at least one surface,
The adhesive layer contains an acrylic copolymer and 0.1 to 5 parts by weight of a silane coupling agent with respect to 100 parts by weight of the acrylic copolymer,
The acrylic copolymer contains 50% by weight or more of structural units derived from a cyclic structure-containing monomer, and has at least one polar functional group selected from the group consisting of a hydroxyl group, a carboxyl group, an amino group, and an epoxy group. Containing a structural unit derived from a monomer having
the product of the number of parts by weight of the structural unit with respect to 100 parts by weight of the acrylic copolymer and the number of the polar functional groups per molecule of the monomer is 0.01 to 4 ;
The pressure-sensitive adhesive layer has a swelling rate of 100% by weight or more and 150% by weight or less after being immersed in a mixture of 80% by weight of isopropanol and 20% by weight of water for 24 hours under conditions of 60° C. and 90% humidity. An adhesive tape characterized by: 3. The pressure-sensitive adhesive tape according to claim 2, wherein the structural unit derived from the cyclic structure-containing monomer is at least one of cyclohexyl (meth)acrylate and isobornyl (meth)acrylate. 4. The pressure-sensitive adhesive tape according to claim 2, wherein the pressure-sensitive adhesive layer contains 0.5 to 5 parts by weight of a silane coupling agent with respect to 100 parts by weight of the acrylic copolymer. 5. The adhesive tape according to claim 1 , 2, 3 or 4, wherein the width is 5 mm or less. 6. The adhesive tape according to claim 1, 2 , 3, 4 or 5, which is used for fixing parts of electronic equipment.