KR20210141938A - Pressure-sensitive adhesive composition, pressure-sensitive adhesive layer and pressure-sensitive adhesive sheet - Google Patents

Abstract

The present invention relates to a pressure-sensitive adhesive composition comprising a base polymer, a leuco dye, and a photoacid generator.

Description

Pressure-sensitive adhesive composition, pressure-sensitive adhesive layer and pressure-sensitive adhesive sheet

The present invention relates to a pressure-sensitive adhesive composition, a pressure-sensitive adhesive layer comprising the pressure-sensitive adhesive composition, and an pressure-sensitive adhesive sheet comprising the pressure-sensitive adhesive layer.

Conventionally, transparent tapes have been favorably used because it is easy to grasp the position of the adhesive tape in a processing process or work such as bonding. On the other hand, the colored adhesive tape is also used for the purpose of a change of design, designability, visibility improvement, etc.

For example, Patent Document 1 describes a colored pressure-sensitive adhesive sheet having a performance of hiding a defect of an adherend by designability, decorative properties, or concealability of the adherend while achieving a thickness reduction of the pressure-sensitive adhesive sheet.

Japanese Patent Laid-Open No. 2013-245298

The adhesive sheet of the said patent document 1 is colored because the adhesive layer contains dye. Therefore, the molded pressure-sensitive adhesive sheet was already colored, and the pressure-sensitive adhesive sheet could not be colored at any timing, such as after the sheet bonding step.

Then, this invention makes it one subject to provide the adhesive composition which can change color or color at arbitrary timings, and the adhesive layer and adhesive sheet using this adhesive composition.

MEANS TO SOLVE THE PROBLEM The present inventors repeated earnest examination for the purpose of providing the adhesive composition etc. which can be discolored or colored at arbitrary timings. As a result, combining the leuco pigment|dye which colors by reacting with an acid, and the photo-acid generator which generate|occur|produces an acid by irradiation of an active energy ray, using for an adhesive composition was conceived. That is, by irradiating an active energy ray to the adhesive composition containing a leuco dye and a photo-acid generator, it discovered that it can change color or colorize at arbitrary timings, and came to complete this invention.

One embodiment of the present invention relates to a pressure-sensitive adhesive composition containing a base polymer, a leuco dye, and a photoacid generator.

In one embodiment of the present invention, it is preferable that the absorption wavelength of the leuco dye changes with pH.

In one embodiment of the present invention, the pressure-sensitive adhesive composition preferably contains 0.1 to 30 parts by mass of the leuco dye per 100 parts by mass of the base polymer.

In one embodiment of the present invention, the leuco dye is preferably at least one dye selected from the group consisting of phthalide dyes and fluoran dyes.

In one Embodiment of this invention, it is preferable that an adhesive composition contains 0.1-30 mass parts of photo-acid generators per 100 mass parts of base polymers.

In one embodiment of the present invention, the photoacid generator is preferably at least one compound selected from the group consisting of a sulfonium salt-based compound, an iodonium salt-based compound, and an aromatic N-oxyimide sulfonate.

In one embodiment of the present invention, the base polymer preferably contains an acrylic polymer.

In one embodiment of the present invention, the pressure-sensitive adhesive composition may be discolored by active energy ray irradiation.

In one embodiment of the present invention, the pressure-sensitive adhesive composition may be colored by irradiation with an active energy ray.

One Embodiment of this invention relates to the adhesive layer which consists of said adhesive composition.

One Embodiment of this invention relates to the adhesive sheet provided with said adhesive layer.

In one embodiment of the present invention, the pressure-sensitive adhesive sheet may have a UV absorption layer on one side of the pressure-sensitive adhesive layer.

In one embodiment of the present invention, the UV absorbing layer may be an adhesive layer containing a UV absorbing agent.

In one Embodiment of this invention, the adhesive layer in an adhesive sheet may be formed on the base material.

The pressure-sensitive adhesive composition of one embodiment of the present invention can be discolored or colored by irradiating an active energy ray. Accordingly, the pressure-sensitive adhesive layer or the pressure-sensitive adhesive sheet using the pressure-sensitive adhesive composition can be discolored or colored at any timing, such as after their bonding.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows an example of the redox reaction of the leuco dye in embodiment of this invention.
It is an example of the schematic sectional drawing of the adhesive layer which concerns on embodiment of this invention.
It is an example of the schematic sectional drawing of the adhesive sheet which concerns on embodiment of this invention.
It is an example of the schematic sectional drawing of the adhesive sheet which concerns on embodiment of this invention.
It is an example of the schematic sectional drawing of the adhesive sheet which concerns on embodiment of this invention.
It is an example of the schematic sectional drawing of the adhesive sheet which concerns on embodiment of this invention.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described in detail. In addition, this invention is not limited to embodiment demonstrated below.

<Adhesive composition>

The adhesive composition of one Embodiment of this invention contains a base polymer, a leuco dye, and a photo-acid generator, It is characterized by the above-mentioned.

According to the pressure-sensitive adhesive layer or pressure-sensitive adhesive sheet obtained using the pressure-sensitive adhesive composition, when irradiated with active energy rays, an acid is generated from the photo-acid generator, and the acid and the leuco dye react, thereby discoloring or coloring the pressure-sensitive adhesive layer or the pressure-sensitive adhesive sheet. . That is, since the pressure-sensitive adhesive layer or pressure-sensitive adhesive sheet obtained by using the pressure-sensitive adhesive composition can be discolored or colored by irradiating active energy rays, it can be discolored or colored at any timing, such as after their bonding.

In this specification, "A to B" which shows a range means "A or more and B or less." In addition, in this specification, "weight" and "mass", "weight%" and "mass %", and "weight part" and "mass part" are respectively handled as synonyms.

In this specification, "discoloration" means that the color changes before and after irradiation with an active energy ray, a color disappears by irradiation with an active energy ray, a color is revealed by irradiation with an active energy ray, and an active energy ray It is a concept that includes changing the original color to another color by irradiation.

In addition, in this specification, "colored" means that the color is revealed before and after irradiation with active energy ray, the color is revealed by irradiation with active energy ray, and the original color is changed to another color by irradiation with active energy ray Although it is a concept including thing, it is a concept which does not include the thing which a color lose|disappears by irradiation of an active energy ray.

Hereinafter, each component contained in the said adhesive composition is demonstrated in detail.

(Base Polymer)

The pressure-sensitive adhesive composition of one embodiment of the present invention WHEREIN: It does not specifically limit as a base polymer which comprises an adhesive composition, It is possible to use the well-known polymer used for an adhesive. For example, an acryl-type polymer, a rubber-type polymer, a vinyl alkyl ether-type polymer, a silicone-type polymer, a polyester-type polymer, a polyamide-type polymer, a urethane-type polymer, a fluorine-type polymer, an epoxy-type polymer, etc. are mentioned. Among them, an acrylic polymer and a rubber polymer are preferable from the viewpoint of adhesiveness. Moreover, from a viewpoint that the change in appearance at the time of discoloration or coloring is remarkable, an acrylic polymer with high transparency is more preferable. In addition, these polymers may be used individually by 1 type, and may be used in combination of 2 or more type.

Hereinafter, in the adhesive composition of one Embodiment of this invention, although embodiment containing an acrylic polymer as a base polymer is mainly demonstrated, this invention is not limited to the said embodiment.

The pressure-sensitive adhesive composition of one embodiment of the present invention may include an acrylic polymer as a base polymer. Typically, the pressure-sensitive adhesive composition may be an acrylic pressure-sensitive adhesive composition containing an acrylic polymer as a main component. The acrylic pressure-sensitive adhesive composition is excellent in transparency.

As the pressure-sensitive adhesive composition of one embodiment of the present invention, for example, a monomer containing (meth)acrylic acid alkyl ester having a linear or branched alkyl group having 1 to 20 carbon atoms at the ester terminal in a proportion of 40 wt% or more It is preferable to contain the acrylic polymer comprised as a component as a base polymer.

Hereinafter, the (meth)acrylic-acid alkylester which has an alkyl group whose carbon number is X or more and Y or less at the ester terminal may be described as "(meth)acrylic-acid C _XY alkyl ester." _{Since it is easy to balance the characteristics, the ratio of (meth)acrylic acid C 1-20} alkyl ester in the whole monomer component of the acrylic polymer according to one embodiment is suitably more than 50% by weight, for example, even if it is 55% by weight or more. It may be 60 weight% or more, and 70 weight% or more may be sufficient as it.

From the same reason, the ratio of (meth)acrylic acid C _1-20 alkylester in the monomer component may be, for example, 99.9% by weight or less, 99.5% by weight or less, or 99% by weight or less. _{The ratio of C 1-20} (meth)acrylic acid alkyl ester to the whole monomer component of the acrylic polymer according to another embodiment may be, for example, 98% by weight or less, or 95% by weight or less from the viewpoint of improving the cohesiveness of the pressure-sensitive adhesive layer and 85 weight% or less (for example, less than 80 weight%) may be sufficient, 70 weight% or less may be sufficient, and 60 weight% or less may be sufficient.

As a non-limiting example of the (meth)acrylic acid C _1-20 alkyl ester, (meth) methyl acrylate, (meth) ethyl acrylate, (meth) acrylic acid propyl, (meth) acrylate isopropyl, (meth) acrylate n-butyl, (meth) acrylate isobutyl, (meth) acrylate s-butyl, (meth) acrylate t-butyl, (meth) acrylate pentyl, (meth) acrylate isopentyl, (meth) acrylate hexyl, (meth) acrylate heptyl, (meth) acrylate ) octyl acrylate, (meth) acrylate 2-ethylhexyl, (meth) acrylate isooctyl, (meth) acrylate nonyl, (meth) acrylate isononyl, (meth) decyl acrylate, (meth) acrylate isodecyl, (meth) Undecyl acrylate, (meth) acrylate dodecyl, (meth) acrylic acid tridecyl, (meth) acrylic acid tetradecyl, (meth) acrylic acid pentadecyl, (meth) acrylic acid hexadecyl, (meth) acrylic acid heptadecyl, (meth) acrylic acid Stearyl, (meth)acrylic acid isostearyl, (meth)acrylic acid nonadecyl, (meth)acrylic acid eicosyl, etc. are mentioned.

Preferable to use at least a (meth) acrylic acid C _4-20 alkyl esters of these, and at least (meth) acrylic acid is more preferred to use a C _4-18 alkyl ester. For example, it is preferable to contain one or both of n-butyl acrylate (BA) and 2-ethylhexyl acrylate (2EHA) as the monomer component, and an acrylic pressure-sensitive adhesive containing at least 2EHA is particularly preferable. As another example of the (meth)acrylic acid C _4-20 alkyl ester that can be preferably used, isononyl acrylate, n-butyl methacrylate (BMA), 2-ethylhexyl methacrylate (2EHMA), isostearyl acrylate ( iSTA) and the like.

In some embodiments, the monomer component constituting the acrylic polymer may include (meth)acrylic acid C _4-18 alkyl ester in a proportion of 40 wt% or more. The ratio of the (meth)acrylic acid C _4-18 alkyl ester to the monomer component may be, for example, 50% by weight or more, 60% by weight or more, or 65% by weight or more. A monomer component containing a _{(meth)acrylic acid C 6-18} alkyl ester in a ratio greater than or equal to any of the lower limits described above may be used.

In addition, from the viewpoint of improving the cohesiveness of the pressure-sensitive adhesive layer, _{the ratio of (meth)acrylic acid C 4-18} alkyl ester to the monomer component is usually 99.5% by weight or less, and may be 95% by weight or less, or 85% by weight. or less may be sufficient, and 75 weight% or less may be sufficient as it. _{A monomer component containing a (meth)acrylic acid C 6-18} alkyl ester may be used in a ratio below any of the above upper limits.

The monomer component constituting the acrylic polymer may contain other monomers (copolymerizable monomers) copolymerizable with the (meth)acrylic acid alkyl ester as needed together with the (meth)acrylic acid alkyl ester. As the copolymerizable monomer, a monomer having a polar group (for example, a carboxyl group, a hydroxyl group, a nitrogen atom-containing ring, etc.) and a monomer having a relatively high glass transition temperature of the homopolymer (for example, 10° C. or higher) can be preferably used. The monomer having a polar group may be helpful in introducing a crosslinking point to the acrylic polymer or in increasing the cohesive force of the pressure-sensitive adhesive. A copolymerizable monomer can be used individually by 1 type or in combination of 2 or more type.

The following are mentioned as a non-limiting specific example of a copolymerizable monomer.

Carboxylic group-containing monomers: For example, acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid and the like.

Acid anhydride group-containing monomers: for example, maleic anhydride, itaconic anhydride.

Hydroxyl group-containing monomer: For example, (meth)acrylic acid 2-hydroxyethyl, (meth)acrylic acid 2-hydroxypropyl, (meth)acrylic acid 2-hydroxybutyl, (meth)acrylic acid 3-hydroxypropyl, (meth)acrylic acid ) Acrylic acid 4-hydroxybutyl, (meth)acrylic acid 6-hydroxyhexyl, (meth)acrylic acid 8-hydroxyoctyl, (meth)acrylic acid 10-hydroxydecyl, (meth)acrylic acid 12-hydroxylauryl, ( (meth)acrylic acid hydroxyalkyl, such as 4-hydroxymethylcyclohexyl)methyl (meth)acrylate.

Monomers containing a sulfonic acid group or a phosphoric acid group: for example, styrenesulfonic acid, allylsulfonic acid, sodium vinylsulfonate, 2-(meth)acrylamide-2-methylpropanesulfonic acid, (meth)acrylamidopropanesulfonic acid, sulfopropyl (meth) ) acrylate, (meth)acryloyloxynaphthalenesulfonic acid, 2-hydroxyethylacryloylphosphate, and the like.

Epoxy group-containing monomers: For example, epoxy group-containing acrylates such as (meth)acrylic acid glycidyl and (meth)acrylic acid-2-ethylglycidyl ether, allyl glycidyl ether, (meth)acrylic acid glycidyl ether, etc. .

Cyano group-containing monomers: For example, acrylonitrile, methacrylonitrile, and the like.

Isocyanate group-containing monomers: For example, 2-isocyanatoethyl (meth)acrylate and the like.

Amide group-containing monomers: for example, (meth)acrylamide; N,N-dimethyl (meth)acrylamide, N,N-diethyl (meth)acrylamide, N,N-dipropyl (meth)acrylamide, N,N- such as N,N-diisopropyl (meth)acrylamide, N,N-di(n-butyl)(meth)acrylamide, N,N-di(t-butyl)(meth)acrylamide, etc. dialkyl (meth) acrylamide; N-alkyl (such as N-ethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N-butyl (meth) acrylamide, Nn-butyl (meth) acrylamide) meth)acrylamide; N-vinylcarboxylic acid amides such as N-vinylacetamide; Monomers having a hydroxyl group and an amide group, for example N-(2-hydroxyethyl)(meth)acrylamide, N-(2-hydroxypropyl)(meth)acrylamide, N-(1-hydroxypropyl)( Meth)acrylamide, N-(3-hydroxypropyl)(meth)acrylamide, N-(2-hydroxybutyl)(meth)acrylamide, N-(3-hydroxybutyl)(meth)acrylamide, N-hydroxyalkyl (meth)acrylamide, such as N-(4-hydroxybutyl) (meth)acrylamide; Monomers having an alkoxy group and an amide group, for example, N-alkoxyalkyl (meth) such as N-methoxymethyl (meth) acrylamide, N-methoxyethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide ) acrylamide; In addition, N,N-dimethylaminopropyl (meth)acrylamide, N-(meth)acryloylmorpholine, etc.

Amino group-containing monomers: for example, aminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, t-butylaminoethyl (meth)acrylate.

Monomers having an epoxy group: For example, glycidyl (meth) acrylate, methyl glycidyl (meth) acrylate, allyl glycidyl ether.

Monomers having a nitrogen atom-containing ring: for example, N-vinyl-2-pyrrolidone, N-methylvinylpyrrolidone, N-vinylpyridine, N-vinylpiperidone, N-vinylpyrimidine, N-vinylpiperidone Razine, N-vinylpyrazine, N-vinylpyrrole, N-vinylimidazole, N-vinyloxazole, N-(meth)acryloyl-2-pyrrolidone, N-(meth)acryloylpiperidine , N-(meth)acryloylpyrrolidine, N-vinylmorpholine, N-vinyl-3-morpholinone, N-vinyl-2-caprolactam, N-vinyl-1,3-oxazin-2- one, N-vinyl-3,5-morpholinedione, N-vinylpyrazole, N-vinyl isoxazole, N-vinylthiazole, N-vinylisothiazole, N-vinylpyridazine, etc. (for example, , lactams such as N-vinyl-2-caprolactam).

Monomers having a succinimide skeleton: for example, N-(meth)acryloyloxymethylenesuccinimide, N-(meth)acryloyl-6-oxyhexamethylenesuccinimide, N-(meth)acryl Royl-8-oxyhexamethylenesuccinimide and the like.

Maleimides: For example, N-cyclohexyl maleimide, N-isopropyl maleimide, N-lauryl maleimide, N-phenyl maleimide, etc.

Itaconimides: For example, N-methyl itaconimide, N-ethyl itaconimide, N-butyl itaconimide, N-octyl itaconimide, N-2-ethylhexyl itacon mide, N-cyclohexyl itaconimide, N-lauril itaconimide, and the like.

Aminoalkyl (meth)acrylic acid: For example, (meth)acrylic acid aminoethyl, (meth)acrylic acid N,N-dimethylaminoethyl, (meth)acrylic acid N,N-diethylaminoethyl, (meth)acrylic acid t- Butylaminoethyl.

Alkoxy group-containing monomers: For example, (meth)acrylic acid 2-methoxyethyl, (meth)acrylic acid 3-methoxypropyl, (meth)acrylic acid 2-ethoxyethyl, (meth)acrylic acid propoxyethyl, (meth) (meth)acrylate alkoxyalkyl (alkoxyalkyl (meth)acrylate) such as butoxyethyl acrylate and ethoxypropyl (meth)acrylate; (meth)acrylic acid alkoxyalkylene glycols such as (meth)acrylic acid methoxyethylene glycol, (meth)acrylic acid methoxypolyethylene glycol, (meth)acrylic acid methoxypolypropylene glycol (for example, alkoxypolyalkylene glycol (meth)acrylic acid) rate).

Alkoxysilyl group-containing monomers: for example 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropyltriethoxysilane, 3-(meth)acryloxypropylmethyldimethoxysilane, 3- Alkoxysilyl group-containing (meth)acrylates, such as (meth)acryloxypropylmethyldiethoxysilane, alkoxysilyl group-containing vinyl compounds, such as vinyl trimethoxysilane and vinyl triethoxysilane, etc.

Vinyl esters: For example, vinyl acetate, vinyl propionate, etc.

Vinyl ethers: For example, vinyl alkyl ethers such as methyl vinyl ether and ethyl vinyl ether.

Aromatic vinyl compounds: For example, styrene, ?-methylstyrene, vinyltoluene, and the like.

Olefins: For example, ethylene, butadiene, isoprene, isobutylene, etc.

(meth)acrylic acid ester having an alicyclic hydrocarbon group: For example, cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, (meth)acrylates containing an alicyclic hydrocarbon group such as damantyl (meth)acrylate.

(meth)acrylic acid ester having an aromatic hydrocarbon group: For example, (meth)acrylate containing an aromatic hydrocarbon group such as phenyl (meth)acrylate, phenoxyethyl (meth)acrylate, benzyl (meth)acrylate.

In addition, heterocyclic ring-containing (meth)acrylates such as tetrahydrofurfuryl (meth)acrylic acid, halogen atom-containing (meth)acrylates such as vinyl chloride and fluorine atom-containing (meth)acrylates, silicone (meth)acrylates Silicon atom-containing (meth)acrylates, such as (meth)acrylic acid ester obtained from terpene compound derivative alcohol.

When using such a copolymerizable monomer, although the usage-amount is not specifically limited, Usually, it is suitable to set it as 0.01 weight% or more of the whole monomer component. From the viewpoint of better exhibiting the effect of using the copolymerizable monomer, the amount of the copolymerizable monomer may be 0.1% by weight or more, or 0.5% by weight or more of the whole monomer component. In addition, from the viewpoint of facilitating balancing of the adhesive properties, the amount of the copolymerizable monomer to be used is usually 50% by weight or less of the entire monomer component, and preferably 40% by weight or less.

In some aspects, the monomer component constituting the acrylic polymer may include a monomer having a nitrogen atom. Thereby, the cohesive force of an adhesive can be raised and the peeling force after time-lapse|temporality can be improved suitably. As one suitable example of the monomer which has a nitrogen atom, the monomer which has a nitrogen-atom containing ring is mentioned. Examples of the monomer having a nitrogen atom-containing ring include those exemplified above, and examples thereof include N-vinyl cyclic amides represented by the following general formula (1).

Here, a general formula ^(1), R 1 is a divalent organic group, specifically, - (CH _{2) n} - is a. n is an integer of 2 to 7 (preferably 2, 3 or 4). Among them, N-vinyl-2-pyrrolidone can be preferably employed. As another suitable example of the monomer which has a nitrogen atom, (meth)acrylamide is mentioned.

The amount of the monomer having a nitrogen atom (preferably a monomer having a nitrogen atom-containing ring) to be used is not particularly limited, and for example, 1% by weight or more, 3% by weight or more, 5% by weight or more, or 7% by weight or more of the entire monomer component. can be done with In one aspect, the usage-amount of the monomer which has a nitrogen atom may be 10 weight% or more of the whole monomer component, 15 weight% or more may be sufficient, and 20 weight% or more may be sufficient as it. Further, the amount of the monomer having a nitrogen atom to be used is, for example, 40% by weight or less of the entire monomer component, and may be 35% by weight or less, 30% by weight or less, or 25% by weight or less. do. In another aspect, the usage-amount of the monomer which has a nitrogen atom is good also as 20 weight% or less for the whole monomer component, and good also as 15 weight% or less.

In some aspects, the monomer component constituting the acrylic polymer may contain a hydroxyl group-containing monomer. By use of a hydroxyl-containing monomer, the cohesive force of an adhesive and the grade of crosslinking (crosslinking by an isocyanate crosslinking agent, for example) can be adjusted suitably. The amount used in the case of using a hydroxyl-containing monomer is not particularly limited, and for example, may be 0.01% by weight or more, may be 0.1% by weight or more, may be 0.5% by weight or more, 1% by weight or more, 5 weight% or more or 10 weight% or more may be sufficient. In addition, from the viewpoint of suppressing the water absorbency of the pressure-sensitive adhesive layer, in some aspects, the amount of the hydroxyl group-containing monomer used is suitably set to, for example, 40% by weight or less of the entire monomer component, and may be 30% by weight or less. , may be 25% by weight or less, or may be 20% by weight or less. In another aspect, the usage-amount of a hydroxyl-containing monomer is good also as 15 weight% or less, 10 weight% or less, or 5 weight% or less of the whole monomer component, for example.

In the pressure-sensitive adhesive composition of one embodiment of the present invention, the monomer component of the acrylic polymer may or may not contain the alkoxyalkyl (meth)acrylate or alkoxypolyalkylene glycol (meth)acrylate exemplified above. . In one aspect of the technology according to this embodiment, the ratio of alkoxyalkyl (meth)acrylate in the monomer component of the acrylic polymer is less than 20% by weight, and the ratio of alkoxypolyalkylene glycol (meth)acrylate is 20% by weight is less than Thereby, the adhesive layer is easy to form a sheet|seat without problems, such as gelatinization. By employing the above monomer composition, the solid content concentration of the monomer mixture is maintained in a predetermined range to obtain a desired high molecular weight (for example, a weight average molecular weight (Mw) ^{greater than 30 × 10 4} , typically Mw 40 × 10 ⁴ or greater). can be polymerized.

The ratio of the alkoxyalkyl (meth)acrylate to the monomer component is preferably less than 10% by weight, more preferably less than 3% by weight, still more preferably less than 1% by weight, and in a particularly preferred embodiment, The monomer component is substantially free of alkoxyalkyl (meth)acrylates (content 0 to 0.3% by weight). Similarly, the proportion of the alkoxypolyalkylene glycol (meth)acrylate in the monomer component is preferably less than 10% by weight, more preferably less than 3% by weight, still more preferably less than 1% by weight, and particularly preferably In one embodiment, the monomer component does not substantially include alkoxypolyalkylene glycol (meth)acrylate (content 0 to 0.3% by weight).

In addition, from the viewpoint of suppressing gelation, the monomer component of the acrylic polymer according to one preferred embodiment has a total ratio of alkoxyalkyl (meth)acrylate and alkoxypolyalkylene glycol (meth)acrylate is limited to less than 20% by weight. . The total ratio of the alkoxyalkyl (meth)acrylate and the alkoxypolyalkylene glycol (meth)acrylate is more preferably less than 10% by weight, still more preferably less than 3% by weight, particularly preferably less than 1% by weight. And, in one embodiment, the monomer component does not substantially include alkoxyalkyl (meth)acrylate and alkoxypolyalkylene glycol (meth)acrylate (content 0 to 0.3% by weight).

Similarly, the monomer component of the acrylic polymer according to the present embodiment may or may not contain an alkoxy group-containing monomer in a proportion of less than 20% by weight. The amount of the alkoxy group-containing monomer in the monomer component is preferably less than 10% by weight, more preferably less than 3% by weight, still more preferably less than 1% by weight, and in one particularly preferred embodiment, the monomer component is alkoxy Substantially free of group-containing monomers (content 0 to 0.3% by weight).

In some aspects, the ratio of the carboxyl group-containing monomer to the monomer component of the acrylic polymer may be, for example, 2% by weight or less, 1% by weight or less, 0.5% by weight or less (for example, less than 0.1% by weight) ) may be It is not necessary to substantially use a carboxyl group-containing monomer as a monomer component of the acrylic polymer. Here, "substantially not using a carboxyl group-containing monomer" means not using a carboxyl group-containing monomer at least intentionally. The acrylic polymer having such a composition tends to be highly reliable in water resistance, and may have metal corrosion preventing properties against an adherend containing a metal.

Further, in a preferred aspect, the proportion of the hydrophilic monomer in the monomer component of the acrylic polymer is limited. Here, the "hydrophilic monomer" in the present specification refers to a carboxyl group-containing monomer, an acid anhydride group-containing monomer, a hydroxyl group-containing monomer, and a nitrogen atom-containing monomer (typically, an amide group-containing monomer such as (meth)acrylamide, N -monomers having a nitrogen atom-containing ring such as vinyl-2-pyrrolidone) and alkoxy group-containing monomers (typically, alkoxyalkyl (meth)acrylate and alkoxypolyalkylene glycol (meth)acrylate) .

In this aspect, it is preferable that the ratio of the said hydrophilic monomer in the monomer component of an acrylic polymer is 32 weight% or less, for example, 30 weight% or less may be sufficient, and 28 weight% or less may be sufficient. Although not specifically limited, the ratio of the said hydrophilic monomer in the monomer component of an acrylic polymer may be 1 weight% or more, 10 weight% or more may be sufficient, and 20 weight% or more may be sufficient as it.

In some aspects, the monomer component constituting the acrylic polymer may include an alicyclic hydrocarbon group-containing (meth)acrylate. Thereby, the cohesive force of an adhesive can be raised and the peeling force after aging can be improved. As an alicyclic hydrocarbon group containing (meth)acrylate, the thing illustrated above can be used, For example, cyclohexyl acrylate and isobornyl acrylate can be employ|adopted preferably.

The amount used in the case of using the alicyclic hydrocarbon group-containing (meth)acrylate is not particularly limited, and may be, for example, 1% by weight or more, 3% by weight or more, or 5% by weight or more of the whole monomer component. In one aspect, the usage-amount of the alicyclic hydrocarbon group containing (meth)acrylate may be 10 weight% or more of the whole monomer component, and 15 weight% or more may be sufficient as it. The upper limit of the amount of the alicyclic hydrocarbon group-containing (meth)acrylate used is suitably about 40% by weight or less, for example, 30% by weight or less, and 25% by weight or less (for example, 15% by weight or less, Furthermore, 10 weight% or less) may be sufficient.

The composition of the monomer component constituting the acrylic polymer may be set such that the glass transition temperature Tg obtained by Fox's formula based on the composition of the monomer component is -75°C or more and 10°C or less. In some aspects, from the viewpoint of cohesiveness and impact resistance, the Tg is suitably 0°C or less, preferably -10°C or less, and may be -20°C or less or -30°C or less. Further, the Tg may be, for example, -60°C or higher, -50°C or higher, -45°C or higher, or -40°C or higher.

Here, as described below, the formula of Fox is a relational expression between Tg of the copolymer and the glass transition temperature Tgi of a homopolymer obtained by homopolymerizing each of the monomers constituting the copolymer.

1/Tg=Σ(Wi/Tgi)

In addition, in the formula of Fox, Tg is the glass transition temperature of the copolymer (unit: K), Wi is the weight fraction of the monomer i in the copolymer (copolymerization ratio based on weight), Tgi is the homo of the monomer i It represents the glass transition temperature (unit: K) of a polymer.

As the glass transition temperature of the homopolymer used for the calculation of Tg, the value described in known materials is used. For example, for the monomers cited below, the following values are used as the homopolymer glass transition temperature of the monomer.

2-ethylhexyl acrylate -70℃

n-Butyl acrylate -55℃

Isostearyl acrylate -18℃

Methyl methacrylate 105°C

Methyl acrylate 8℃

Cyclohexyl acrylate 15℃

N-vinyl-2-pyrrolidone 54°C

2-hydroxyethyl acrylate -15℃

4-hydroxybutyl acrylate -40℃

Dicyclofentanyl methacrylate 175°C

Isobornyl acrylate 94℃

Acrylic acid 106℃

methacrylic acid 228℃

For monomer homopolymer glass transition temperatures other than those exemplified above, the numerical values described in "Polymer Handbook" (3rd ed., John Wiley & Sons, Inc., 1989) shall be used. When multiple types of values are described in this document, the highest value is employed.

For monomers in which the glass transition temperature of the homopolymer is not described in the Polymer Handbook, a value obtained by the following measurement method is used (see Japanese Patent Application Laid-Open No. 2007-51271).

Specifically, 100 parts by weight of a monomer, 0.2 parts by weight of azobisisobutyronitrile, and 200 parts by weight of ethyl acetate as a polymerization solvent were introduced into a reactor equipped with a thermometer, a stirrer, a nitrogen introduction tube and a reflux cooling tube, and nitrogen gas was introduced into the reactor. Agitate for 1 hour while circulating. After removing oxygen in the polymerization system in this way, the temperature is raised at 63° C. and the reaction is carried out for 10 hours. Then, it is cooled to room temperature to obtain a homopolymer solution having a solid content concentration of 33% by weight. Next, this homopolymer solution is applied by casting on a release liner and dried to prepare a test sample (sheet-shaped homopolymer) having a thickness of about 2 mm. This test sample is punched out into a disk shape with a diameter of 7.9 mm, sandwiched between parallel plates, and shear deformation of a frequency (1 Hz) is applied using a viscoelasticity tester (ARES, manufactured by Rheometrics) in a temperature range of -70 to The viscoelasticity is measured by shear mode at 150°C and a temperature increase rate of 5°C/min, and the peak top temperature of tan δ is taken as Tg of the homopolymer.

Although the acrylic polymer which concerns on this embodiment is not specifically limited, It is preferable that ^{SP value is 23.0 (MJ/m<3>) 1/2 or less.} The SP value is more preferably 21.0 (MJ/m 3 ) ^1/2 or less (eg, 20.0 (MJ/m 3 ) ^1/2 or less). The lower limit of the SP value is not particularly limited, and for example, it is preferably about 10.0 (MJ/m 3 ) ^1/2 or more, and preferably about 15.0 (MJ/m 3 ) ^1/2 or more, and preferably 18.0 (MJ/m 3 ) 1/2 or more. m3) is more than ^1/2.

In addition, the SP value of the acrylic polymer is calculated by Fedors' method [see "Polymer Engineering & Science (POLYMER ENG. & SCI.)," Vol. 14, No. 2 (1974), pages 148 to 154), i.e. , ceremony:

SP value δ=(ΣΔe/ΣΔv) ^1/2

(wherein Δe is the evaporation energy Δe of each atom or group at 25°C, and Δv is the molar volume of each atom or group at the same temperature); The acrylic polymer having the above SP value can be obtained by appropriately determining the monomer composition based on the technical common knowledge of those skilled in the art.

The pressure-sensitive adhesive composition includes the monomer component having the composition as described above in the form of a polymer, a non-polymer (ie, a form in which the polymerizable functional group is unreacted) or a mixture thereof. The pressure-sensitive adhesive composition is a water-dispersible pressure-sensitive adhesive composition in which the pressure-sensitive adhesive (adhesive component) is dispersed in water, a solvent-type pressure-sensitive adhesive composition containing the pressure-sensitive adhesive in an organic solvent, and an active energy ray such as ultraviolet rays or radiation to cure the pressure-sensitive adhesive It may be in various forms, such as an active energy ray-curable pressure-sensitive adhesive composition prepared to form, a hot-melt pressure-sensitive adhesive composition that is coated in a heat-melted state and forms a pressure-sensitive adhesive when cooled to near room temperature. The pressure-sensitive adhesive composition according to one preferred embodiment is a solvent-type pressure-sensitive adhesive composition or a non-solvent-type pressure-sensitive adhesive composition. An active energy ray-curable adhesive composition and a hot-melt type adhesive composition are contained in a non-solvent type adhesive composition.

For polymerization, a known or customary thermal polymerization initiator or radical photopolymerization initiator can be used according to a polymerization method, polymerization mode, or the like. Such a polymerization initiator can be used individually by 1 type or in combination of 2 or more types suitably.

Although it does not specifically limit as a thermal polymerization initiator, For example, an azo polymerization initiator, a peroxide type initiator, a redox type initiator by the combination of a peroxide and a reducing agent, a substituted ethane type initiator, etc. can be used.

More specifically, for example, 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis(2-methylpropionamidine)disulfate, 2,2'-azobis(2) -amidinopropane)dihydrochloride, 2,2'-azobis[2-(5-methyl-2-imidazolin-2-yl)propane]dihydrochloride, 2,2'-azobis(N, Azo initiators, such as N'-dimethylene isobutylamidine and 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropionamidine]hydrate; For example, potassium persulfate, persulfate Persulfates such as ammonium; Peroxide-based initiators such as benzoyl peroxide, t-butyl hydroperoxide, and hydrogen peroxide; For example, substituted ethane-based initiators such as phenyl-substituted ethane; For example, a combination of persulfate and sodium hydrogen sulfite, peroxide A redox initiator such as a combination of sodium ascorbate and the like; It can be carried out preferably.

Although it does not specifically limit as a radical photopolymerization initiator, For example, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one; 1-Hydroxy-cyclohexyl-phenyl-ketone, benzophenone, 2,2-dimethoxy-1,2-diphenylethan-1-one, 2,4,6-trimethylbenzoyl-diphenyl-phosphineoxide, 2,4,6-Trimethylbenzoyl-phenylethoxy-phosphineoxide, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1,2-hydroxy-2-methyl -1-phenyl-propan-1-one, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, benzoin methyl ether, benzoin ethyl ether, benzoin isobutyl Ether, benzoin isopropyl ether, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, 2-hydroxy-2-methyl-[4-(1-methylvinyl)phenyl]propanol oligomer, 2- Hydroxy-2-methyl-1-phenyl-1-propanone, isopropylthioxanthone, methyl o-benzoylbenzoate, [4-(methylphenylthio)phenyl]phenylmethane, 2,4-diethylthioxanthone, 2-chlorothioxanthone, ethylanthraquinone, benzophenone ammonium salt, thioxanthone ammonium salt, bis(2,6-dimethylbenzoyl)-2,4,4-trimethyl-pentylphosphine oxide, 2,4,6-trimethyl Benzophenone, 4-methylbenzophenone, 4,4'-bisdiethylaminobenzophenone, 1,4-dibenzoyl benzene, 10-butyl-2-chloroacridone, 2,2'-bis(o-chloro Phenyl)-4,5,4',5'-tetrakis(3,4,5-trimethoxyphenyl)-1,2'-biimidazole, 2,2'-bis(o-chlorophenyl)- 4,5,4',5'-tetraphenyl-1,2'-biimidazole, 2-benzoylnaphthalene, 4-benzoylbiphenyl, 4-benzoyldiphenyl ether, acrylated benzophenone, bis(η5-2, 4-Cyclopentadien-1-yl)-bis[2,6-difluoro-3-(1H-pyrrol-1-yl)-phenyl]titanium, o-methylbenzoylbenzoate, p-dimethylaminobenzoate ethyl ester, p-dimethylaminobenzoic acid isoamylethyl ester, active tertiary amine, arbazole-phenone-based photopolymerization initiator, acridine-based photopolymerization initiator, triazine-based photopolymerization initiator, benzoyl-based photopolymerization initiator, and the like. These are used individually or in combination of 2 or more types.

The usage-amount of such a thermal polymerization initiator or radical photopolymerization initiator can be set as the normal usage-amount according to a polymerization method, a polymerization aspect, etc., and is not specifically limited. For example, about 0.001-5 mass parts (typically about 0.01-2 mass parts, for example, about 0.01-1 mass part) of a polymerization initiator can be used with respect to 100 mass parts of monomers to be superposed|polymerized.

For the polymerization, if necessary, various conventionally known chain transfer agents (which may also be regarded as molecular weight regulators or polymerization degree regulators) can be used. As the chain transfer agent, mercaptans such as n-dodecyl mercaptan, t-dodecyl mercaptan, thioglycolic acid and α-thioglycerol can be used. Alternatively, a chain transfer agent (non-sulfur chain transfer agent) not containing a sulfur atom may be used.

Specific examples of the non-sulfur chain transfer agent include anilines such as N,N-dimethylaniline and N,N-diethylaniline; terpenoids such as α-pinene and terpinolene; styrenes such as α-methylstyrene and α-methylstyrene dimer; compounds having a benzylidenyl group such as dibenzylideneacetone, cinnamyl alcohol, and cinnamylaldehyde; hydroquinones such as hydroquinone and naphthohydroquinone; quinones such as benzoquinone and naphthoquinone; olefins such as 2,3-dimethyl-2-butene and 1,5-cyclooctadiene; alcohols such as phenol, benzyl alcohol, and allyl alcohol; benzyl hydrogens such as diphenylbenzene and triphenylbenzene; and the like.

A chain transfer agent can be used individually by 1 type or in combination of 2 or more type. When using a chain transfer agent, the usage-amount can be made into about 0.01-1 mass part about with respect to 100 mass parts of monomer components, for example. The technique according to the present embodiment can be preferably implemented even in an aspect in which a chain transfer agent is not used.

The molecular weight of the acrylic polymer obtained by appropriately employing the above various polymerization methods is not particularly limited, and may be set within an appropriate range according to the required performance. The weight average molecular weight (Mw) of the acrylic polymer is usually about 10×10 ⁴ or more (for example, 20×10 ⁴ or more), and from the viewpoint of achieving good balance between cohesive force and adhesive force, it is preferable to set it to more than ^{30×10 4 .} It is suitable. From the viewpoint of obtaining good adhesion reliability even in a high-temperature environment, the acrylic polymer according to one embodiment is preferably 40×10 ⁴ or more (typically about 50×10 ⁴ or more, for example, about 55×10 ⁴ or more). has Mw. According to a preferred embodiment of the technique according to the present embodiment, since gelation can be suppressed by designing the monomer composition, it is possible to obtain a high molecular weight substance in the above range with high productivity by setting an appropriate solid content concentration. The upper limit of Mw of the acrylic polymer may be generally about 500×10 ⁴ or less (eg, about 150×10 ⁴ or less). The Mw may be approximately 75×10 ⁴ or less.

Here, Mw means the value in terms of standard polystyrene obtained by gel permeation chromatography (GPC). As a GPC apparatus, what is necessary is just to use the model name "HLC-8320GPC" (column: TSkgelGMH-H(S), Tosoh Corporation make), for example. It is the same also in the Example mentioned later. Said Mw may be Mw of the acrylic polymer in any one of an adhesive layer in an adhesive composition.

The pressure-sensitive adhesive composition according to some embodiments may be an active energy ray-curable pressure-sensitive adhesive composition. Examples of active energy rays as used herein include light such as ultraviolet rays, visible rays, and infrared rays, and radiation such as α rays, β rays, γ rays, electron beams, neutron rays, and X rays. An energy ray having energy capable of causing a chemical reaction such as decomposition is mentioned.

In the pressure-sensitive adhesive composition of one embodiment of the present invention, the timing at which the active energy ray-curable pressure-sensitive adhesive composition cures and the timing at which discoloration or coloring is different can be controlled so that discoloration or coloring is possible at any timing. desirable. That is, the timing of the chemical reaction such as polymerization reaction, crosslinking reaction, or decomposition of the initiator of the active energy ray-curable pressure-sensitive adhesive composition, and the photoacid generator or photobase generator described later react, so that the timing of discoloration or coloring of the leuco dye does not overlap. , it is preferable to select the type of each component. In other words, energy rays causing chemical reactions such as polymerization reaction, crosslinking reaction, and decomposition of the initiator are energy rays with which the photoacid generator or photobase generator, which will be described later, react, so that the wavelength for generating the reaction is different. It is desirable to design the composition.

As one suitable example of an active energy ray-curable adhesive composition, a photocurable adhesive composition is mentioned. The photocurable adhesive composition has the advantage that it can form easily even if it is a thick adhesive layer. Among them, an ultraviolet curable pressure-sensitive adhesive composition is preferable.

The photocurable pressure-sensitive adhesive composition typically contains at least a part of the monomer component of the composition (the kind of the monomer may be a part or the quantity may be a part) in the form of a polymer. The polymerization method at the time of forming the said polymer is not specifically limited, A conventionally well-known various polymerization method is employable suitably. For example, thermal polymerization (typically performed in the presence of a thermal polymerization initiator) such as solution polymerization, emulsion polymerization, and bulk polymerization; photopolymerization performed by irradiating light such as ultraviolet rays (typically performed in the presence of a radical photopolymerization initiator); radiation polymerization performed by irradiating radiation such as β-rays and γ-rays; etc. can be appropriately employed. Among them, photopolymerization is preferable.

A photocurable pressure-sensitive adhesive composition according to a preferred embodiment contains a partial polymer of a monomer component. Such a partially polymerized product is typically a mixture of a polymer derived from a monomer component and an unreacted monomer, and preferably exhibits a syrupy state (viscous liquid). Hereinafter, the partial polymer of such properties may be referred to as "monomer syrup" or simply "syrup". The polymerization method in particular at the time of carrying out partial polymerization of a monomer component is not restrict|limited, Various polymerization methods as mentioned above can be used, selecting suitably. From the viewpoint of efficiency and simplicity, a photopolymerization method can be preferably employed. According to photopolymerization, the polymerization conversion rate (monomer conversion) of a monomer component can be easily controlled by polymerization conditions, such as irradiation amount (light quantity) of light.

The polymerization conversion ratio of the monomer mixture in the said partial polymer is not specifically limited. The polymerization conversion ratio can be, for example, approximately 70% by weight or less, and is preferably approximately 60% by weight or less. From the viewpoints of ease of preparation and coatability of the pressure-sensitive adhesive composition containing the partially polymerized product, the polymerization conversion ratio is usually preferably about 50% by weight or less, and about 40% by weight or less (for example, about 35% by weight or less). desirable. Although the lower limit in particular of the polymerization conversion rate is not restrict|limited, Typically, it is about 1 weight% or more, Usually, it is suitable to set it as about 5 weight% or more.

The pressure-sensitive adhesive composition containing the partial polymerization product of the monomer component can be obtained by, for example, partially polymerizing a monomer mixture containing the entire amount of the monomer component used in the preparation of the pressure-sensitive adhesive composition by a suitable polymerization method (for example, photopolymerization method). have. In addition, the pressure-sensitive adhesive composition containing the partial polymerization product of the monomer component may be a mixture of a partial polymerization product or a complete polymerization product of a monomer mixture containing a part of the monomer components used in the preparation of the pressure-sensitive adhesive composition, and the remaining monomer component or a partial polymerization product thereof. do. In addition, in this specification, a "completely polymerized product" means that a polymerization conversion ratio is more than 95 weight%.

(leuco pigment)

The pressure-sensitive adhesive composition of one embodiment of the present invention contains a leuco dye. In the present specification, the leuco dye refers to an organic dye whose color tone reversibly changes with oxidation-reduction. The absorption wavelength may change with pH. More specifically, it refers to a reduced-type dye having one or two or more hydrogen atoms that forms a dye and develops color by adding electrons or removing electrons. The leuco dye has a colorless or weak color in a neutral or alkaline medium, but when it reacts with an acidic substance or an electron-withdrawing substance, the lactone ring becomes a ring-opened state as shown in FIG. 1 and is a pigment|dye which colors. Among the leuco dyes, by selecting those that are substantially colorless or have a weak color before electrons are removed, it becomes possible to observe a change in color remarkably.

In this embodiment, a leuco pigment|dye is colored with the acid which generate|occur|produces by irradiating an active energy ray to the photo-acid generator mentioned later.

Further, in the present embodiment, the leuco dye can be colored with the lactone ring in a ring-opening state, and then the lactone ring can be ring-closed and colored by reacting with a base. The said base can also be generated by irradiating an active energy ray to the photobase generator mentioned later.

As the leuco dye according to the present embodiment, for example, phthalide dyes (such as indolinophthalide or triphenylmethanephthalide), fluoran dye, triphenylmethane dye, phenothiazine dye, auramin dye, and spiropyran and leuco compounds such as dyes.

The leuco dye is preferably at least one leuco dye particularly selected from the group consisting of phthalide dyes and fluoran dyes from the viewpoint of excellent color development.

Specific examples of the leuco dye include the following compounds.

2'-anilino-6'-(N,N-dipentan-1-ylamino)-3'-methyl-3H-spiro[isobenzofuran-1,9'-xanthene]-3-one, 2 -anilino-3-methyl-6-dibutylaminofluoran, 2-anilino-3-methyl-6-difentylaminofluoran, 2-anilino-3-methyl-6-[ethyl (4-methylphenyl) )Amino]fluoran, 3,3-bis(p-dimethylaminophenyl)-phthalide, 3,3-bis(p-dimethylaminophenyl)-6-dimethylaminophthalide (alias: Crystal Violet Lactone, 3 ,3-bis(p-dimethylaminophenyl)-6-diethylaminophthalide, 3,3-bis(p-dimethylaminophenyl)-6-chlorphthalide, 3,3-bis(p-dibutyl Aminophenyl)phthalide, 3-cyclohexylamino-6-chlorofluoran, 3-dimethylamino-5,7-dimethylfluoran, 3-(N-methyl-N-isobutyl)-6-methyl-7- Anilinofluoran, 3-(N-ethyl-N-isoamyl)-6-methyl-7-anilinofluoran, 3-diethylamino-7-chlorofluoran, 3-diethylamino-7-methyl Fluoran, 3-diethylamino-7,8-benzfluoran, 3-diethylamino-6-methyl-7-chlorofluoran, 3-(Np-tolyl-N-ethylamino)-6-methyl- 7-anilinofluoran, 3-pyrrolidino-6-methyl-7-anilinofluoran, 2-{N-(3'-trifluoromethylphenyl)amino}-6-diethylaminofluoran, 2 -{3,6-bis(diethylamino)-9-(o-chloranilino)xanthylbenzoate lactam}3-diethylamino-6-methyl-7-(m-trichloromethylanilino)fluoran , 3-diethylamino-7-(o-chloranilino)fluoran, 3-dibutylamino-7-(o-chloranilino)fluoran, 3-(N-methyl-N-amylamino)- 6-Methyl-7-anilinofluoran, 3-(N-methyl-N-cyclohexylamino)-6-methyl-7-anilinofluoran, 3-diethylamino-6-methyl-7-anilino Fluoran, 3-diethylamino-6-methyl-7-(2',4'-dimethylanilino)fluoran, 3-(N,N-diethylamino)-5-methyl-7-(N, N-dibenzylamino) fluoran, benzoyl leucomethylene blue, 6'-chloro-8'-methoxy-benzoindolino-spiropyran, 6'-bromo-3'-methoxy-benzoindolino-spiro pyran, 3-(2'-hydroxy-4'- Dimethylaminophenyl)-3-(2'-methoxy-5'-chlorophenyl)phthalide, 3-(2'-hydroxy-4'-dimethylaminophenyl)-3-(2'-methoxy-5 '-Nitrophenyl) phthalide, 3-(2'-hydroxy-4'-diethylaminophenyl)-3-(2'-methoxy-5'-methylphenyl) phthalide, 3-(2'-methyl Toxy-4'-dimethylaminophenyl)-3-(2'-hydroxy-4'-chlor-5'-methylphenyl)phthalide, 3-morpholino-7-(N-propyl-trifluoromethylanyl) Rhino) fluoran, 3-pyrrolidino-7-trifluoromethylanilinofluoran, 3-diethylamino-5-chloro-7- (N-benzyl-trifluoromethylanilino) fluoran, 3 -pyrrolidino-7-(di-p-chlorophenyl)methylaminofluoran, 3-diethylamino-5-chlor-7-(α-phenylethylamino)fluoran, 3-(N-ethyl-p -Toluidino)-7-(α-phenylethylamino)fluoran, 3-diethylamino-7-(o-methoxycarbonylphenylamino)fluoran, 3-diethylamino-5-methyl- 7-(α-phenylethylamino)fluoran, 3-diethylamino-7-piperidinofluoran, 2-chloro-3-(N-methyltoluidino)-7-(pn-butylanilino) Fluorane, 3-(N-methyl-N-isopropylamino)-6-methyl-7-anilinofluoran, 3-dibutylamino-6-methyl-7-anilinofluoran, 3,6-bis (dimethylamino)fluorenespiro(9,3′)-6′-dimethylaminophthalide, 3-(N-benzyl-N-cyclohexylamino)-5,6-benzo-7-α-naphthylamino -4'-Bromofluoran, 3-diethylamino-6-chlor-7-anilinofluoran, 3-{N-ethyl-N-(2-ethoxypropyl)amino}-6-methyl-7 -anilinofluoran, 3-{N-ethyl-N-tetrahydrofurfurylamino}-6-methyl-7-anilinofluoran, 3-diethylamino-6-methyl-7-methidino-4 ',5'-benzofluoran, 3-(p-dimethylaminophenyl)-3-{1,1-bis(p-dimethylaminophenyl)ethylene-2-yl}phthalide, 3-(p-dimethylamino Phenyl)-3-{1,1-bis(p-dimethylaminophenyl)ethylene-2-yl}-6-dimethylaminophthalide, 3-(p-dimethylaminophenyl)-3-(1-p- Dimethylaminophenyl-1-phenylethylene-2-yl)phthalide, 3-(p-dimethyla minophenyl)-3-(1-p-dimethylaminophenyl-1-p-chlorophenylethylene-2-yl)-6-dimethylaminophthalide, 3-(4′-dimethylamino-2′-methoxy )-3-(1"-p-dimethylaminophenyl-1"-p-chlorophenyl-1",3"-butadien-4"-yl)benzophthalide, 3-(4'-dimethylamino-2' -Benzyloxy)-3-(1"-p-dimethylaminophenyl-1"-phenyl-1",3"-butadien-4"-yl)benzophthalide, 3-dimethylamino-6-dimethylamino-flu Orene-9-spiro-3'(6'-dimethylamino)phthalide, 6-(diethylamino)-2-[(3-trifluoromethyl)anilino]xanthene-9-spiro-3'- phthalide, 3,3-bis{2-(p-dimethylaminophenyl)-2-(p-methoxyphenyl)ethenyl}-4,5,6,7-tetrachlorophthalide, 3-bis{ 1,1-bis(4-pyrrolidinophenyl)ethylene-2-yl}-5,6-dichloro-4,7-dibromophthalide, bis(p-dimethylaminostyryl)-1-naphthalenesulfide Ponylmethane, bis(p-dimethylaminostyryl)-1-p-tolysulfonylmethane.

The leuco pigment|dye which concerns on this embodiment may be used individually by 1 type, and may mix and use 2 or more types.

In an embodiment of the present invention, the amount of the leuco dye is preferably 0.01 to 30 parts by mass, more preferably 0.1 to 30 parts by mass, still more preferably 0.1 to 20 parts by mass, and more preferably 1 to 30 parts by mass, per 100 parts by mass of the base polymer. It is more preferable that it is 10 mass parts. By being in the said range, discoloration or coloring by a leuco dye can be observed remarkably.

(Mine generator)

The pressure-sensitive adhesive composition of one embodiment of the present invention contains a photoacid generator. In the present specification, the photo-acid generator is not limited to light such as ultraviolet rays, visible rays, and infrared rays, and is an acid by irradiating active energy rays such as α-rays, β-rays, γ-rays, electron beams, neutron rays, and X-rays. It is a compound that can generate (cation). Since the photo-acid generator irradiates the active energy ray and generates an acid as rain, by using it together with the leuco dye, the pressure-sensitive adhesive layer or pressure-sensitive adhesive sheet obtained using the pressure-sensitive adhesive composition can be discolored or colored at any timing.

The photoacid generator is not particularly limited as long as it is a compound capable of generating an acid (cation) by irradiating an active energy ray, for example, a sulfonium salt-based compound, an iodonium salt-based compound, an aromatic N-oxyimide sulfonate, or a sulfonic acid ester. compounds and halomethyl-substituted-S-triazine derivatives; and the like.

From the viewpoint of good compatibility with other components of the pressure-sensitive adhesive composition according to the present invention, the photoacid generator is particularly selected from the group consisting of sulfonium salt-based compounds, iodonium salt-based compounds and aromatic N-oxyimide sulfonates It is preferably at least one compound.

Specific examples of the sulfonium salt-based compound include dimethylphenacylsulfonium, dimethylbenzylsulfonium, dimethyl-4-hydroxyphenylsulfonium, dimethyl-4-hydroxynaphthylsulfonium, dimethyl-4,7-dihydroxy Naphthylsulfonium, dimethyl-4,8-dihydroxynaphthylsulfonium, triphenylsulfonium, p-tolyldiphenylsulfonium, p-tert-butylphenyldiphenylsulfonium, diphenyl-4-phenylthiophenylsulfonium Cations such as phonium, chloride, bromide, p-toluenesulfonate, trifluoromethane sulfonate, tetrafluoroborate, tetrakispentafluorophenyl borate, tetrakispentafluorophenyl gallate, hexafluorophosphate and salts composed of anions such as hexafluoroarsenate, hexafluoroantimonate and nonafluorobutane sulfonate.

Examples of the iodonium salt compound include diphenyliodonium, bis(p-chlorophenyl)iodonium, ditolyliodonium, bis(p-tert-butylphenyl)iodonium, and p-isopropylphenyl. -p-methylphenyliodonium, bis(m-nitrophenyl)iodonium, p-tert-butylphenylphenyliodonium, p-methoxyphenylphenyliodonium, bis(p-methoxyphenyl)iodonium Cations, such as nium, p-octyloxyphenylphenyliodonium, and p-phenoxyphenyliodonium, chloride, bromide, p-toluenesulfonate, trifluoromethanesulfonate, tetrafluoroborate, tetrakispentafluoro and salts composed of anions such as rophenyl bolate, tetrakispentafluorophenyl gallate, hexafluorophosphate, hexafluoroarsenate, hexafluoroantimonate, and nonafluorobutanesulfonate.

Examples of the aromatic N-oxyimide sulfonate include N-(trifluoromethylsulfonyloxy)succinimide, N-(trifluoromethylsulfonyloxy)phthalimide, and N-(trifluoromethylsulfonate). Ponyloxy)diphenylmaleimide, N-(trifluoromethylsulfonyloxy)bicyclohept-5-ene-2,3-dicarboxyimide and N-(trifluoromethylsulfonyloxy)naphthylimide and the like.

Examples of the sulfonic acid ester compound include benzointosylate, α-methylolbenzointosylate, o-nitrobenzyl p-toluenesulfonate, and p-nitrobenzyl-9,10-diethoxyanthracene-2-sulfonate. can be heard Specific examples of the halomethyl-substituted-S-triazine derivative include 2,4,6-tris(trichloromethyl)-S-triazine, 2-methyl-4,6-bis(trichloromethyl)-S-triazine , 2-phenyl-4,6-bis(trichloromethyl)-S-triazine, 2-methyl-4,6-bis(tribromomethyl)-S-triazine, and the like.

In an embodiment of the present invention, the photoacid generator is preferably 0.001 to 30 parts by mass, more preferably 0.01 to 25 parts by mass, still more preferably 0.1 to 30 parts by mass, and 0.1 to 30 parts by mass per 100 parts by mass of the base polymer. It is more preferable that it is 20 mass parts. By being in the said range, an acid can be efficiently generated by active energy ray irradiation, and discoloration or coloring can be observed remarkably.

(photobase generator)

The pressure-sensitive adhesive composition of one embodiment of the present invention may include a photobase generator. The photobase generator is not limited to light such as ultraviolet rays, visible rays, and infrared rays, but is a base (anion) by irradiating active energy rays such as radiation such as α-rays, β-rays, γ-rays, electron beams, neutron rays, and X-rays. compounds that can generate Since a photobase generator irradiates the said active energy ray and a base generate|occur|produces as rain, after coloring a leuco dye, it can reduce|restore a leuco dye at arbitrary timings and can lose|disappear the said coloring.

Moreover, when the adhesive composition of one Embodiment of this invention contains a photobase generator, so that a photobase generator may not generate|occur|produce a base at the same timing as that a photoacid generator generates an acid by active energy ray irradiation, It is preferable to set a combination of a photoacid generator and a photobase generator. That is, it is preferable to design a photobase generator so that a base may generate|occur|produce by the type of active energy ray different from the active energy ray required for a photoacid generator to generate|occur|produce an acid.

The photobase generator is not particularly limited as long as it is a compound capable of generating a base (anion) by irradiating an active energy ray, for example, a transition metal complex, a compound having a benzyl carbamate structure, or an ortho-substituted nitrobenzene structure. Compounds, oximes, imidazole derivatives, benzoin compounds, compounds having an N-formylated aromatic amino group, compounds having an N-acylated aromatic amino group, compounds having an alkoxybenzylcarbamate group, 1,4-dihydropyridine skeleton compounds, oxime esters, and quaternary ammonium salts having

It is preferable that it is 0.001-30 mass parts, and, as for the photobase generator which concerns on this embodiment, it is more preferable that it is 0.01-25 mass parts, It is still more preferable that it is 0.1-20 mass parts per 100 mass parts of said base polymers. By being in the said range, a base can be efficiently generated by active energy ray irradiation, and the discoloration of the colored adhesive sheet is attained.

(Peel strength enhancing agent)

The pressure-sensitive adhesive composition of one embodiment of the present invention may include a peel strength increasing agent. As said peeling force increasing agent, after adhering the surface (adhesive surface) of the adhesive layer formed from the said adhesive composition to a to-be-adhered body, the material which can exhibit the function of raising the peeling force from the to-be-adhered body of an adhesive sheet is suitably used, You can choose to use it. As said peeling force increasing agent, a well-known silane coupling agent can be used, for example. It is preferable that the peeling force increasing agent is contained in the pressure-sensitive adhesive composition (further, the pressure-sensitive adhesive layer) in the form of glass. It is preferable that the said peeling force increasing agent is not chemically bonded with the other structural component which may typically be contained in the said adhesive composition (further, an adhesive layer). In such a form, the peeling force increasing agent contained in the pressure-sensitive adhesive composition can effectively contribute to the improvement of the peeling force.

A silane coupling agent is typically a compound which contains the functional group X and the functional group Y in 1 molecule, and the said functional group X is an alkoxysilyl group. The said alkoxysilyl group is a functional group which has at least 1 alkoxy group on a silicon atom. The silane coupling agent is supplied to the surface of the pressure-sensitive adhesive layer after attachment to the adherend, whereby the silanol group generated by hydrolysis of the alkoxy group reacts with the hydroxyl group on the surface of the adherend, thereby reducing the peeling force of the pressure-sensitive adhesive sheet from the adherend. can elevate The said alkoxysilyl group produces|generates a silanol group which reacts with the hydroxyl group on the to-be-adhered body surface by hydrolysis. Therefore, the said alkoxysilyl group is a precursor of the group which reacts with the said hydroxyl group.

The alkoxy group constituting the alkoxysilyl group is typically a methoxy group or an ethoxy group. Usually, a more hydrolyzable methoxy group is preferable. A trialkoxysilyl group may be sufficient as the said alkoxysilyl group, and a dialkoxysilyl group may be sufficient as it. From a viewpoint of heightening the peeling force synergistic effect, some aspect WHEREIN: The silane coupling agent which has a trialkoxy silyl group is employable preferably.

The functional group Y may be, for example, an epoxy group, an amino group, an isocyanate group (which may constitute an isocyanurate body), an acetoacetyl group, a (meth)acryloyl group, a mercapto group, a vinyl group, or a halogenated alkyl group. As examples of the silane coupling agent having such a functional group Y, for example, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2 Epoxy group-containing silane coupling agents such as -(3,4-epoxycyclohexyl)ethyltrimethoxysilane; For example, amino group-containing silanes such as 3-aminopropyltrimethoxysilane, N-(2-aminoethyl)3-aminopropyltrimethoxysilane, and N-(2-aminoethyl)3-aminopropylmethyldimethoxysilane coupling agent; For example, Isocyanate group containing silane coupling agents, such as 3-isocyanate propyl triethoxysilane and tris (trimethoxysilyl propyl) isocyanurate; acetoacetyl group-containing silane coupling agents such as acetoacetyl group-containing trimethoxysilane; For example, (meth)acryloyl group-containing silane coupling agents such as 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane; vinyl trime Vinyl group-containing silane coupling agents such as oxysilane and vinyltriethoxysilane; Mercapto group-containing silane coupling agents such as 3-methacryloxypropylmethyldimethoxysilane and 3-methacryloxypropyltrimethoxysilane; halogenated alkyl group-containing silane coupling agents such as 3-chloropropyltrimethoxysilane; and the like. Especially, epoxy-group containing silane coupling agents, such as glycidoxy propyl trialkoxy silane (For example, 3-glycidoxy propyl trimethoxy silane and 3-glycidoxy propyl triethoxy silane), are preferable.

As said silane coupling agent, what has the functional group Y which reacts with the functional group y contained in an adhesive layer can be used. A combination of a silane coupling agent having a carboxy group as the functional group y and an epoxy group as the functional group Y is exemplified from the viewpoint of reactivity at room temperature. Examples of other combinations include a combination of an amino group and an epoxy group, a combination of a hydroxyl group and an epoxy group, a combination of a carboxy group and an amino group, a combination of an isocyanate group and an amino group, a combination of a sulfo group and an amino group, and the like. On the other hand, some aspects WHEREIN: The functional group Y of a silane coupling agent from a viewpoint of making the adhesive composition easy to transfer the said peeling force increasing agent to the surface by maintaining the peeling force increasing agent in the state of glass in the said adhesive composition. It may not have a functional group y (eg, a carboxyl group) that reacts with (eg, an epoxy group).

The molecular weight (chemical formula) of the silane coupling agent is not particularly limited, and may be, for example, about 120 to 1000. Usually, a silane coupling agent having a molecular weight of 180 or more, 200 or more, or 220 or more is preferable from the viewpoint of ease of adjustment of the reworkable period and mobility to the adhesive surface. From the same reason, the silane coupling agent whose molecular weight is 800 or less, 600 or less, 400 or less, or 300 or less is preferable. Some aspects WHEREIN: The silane coupling agent whose molecular weight is 200 or more and 300 or less can be used preferably. As a value of the molecular weight of a silane coupling agent, the value computed based on the structural formula of this silane coupling agent is used. Alternatively, the manufacturer's nominal value may be used.

The quantity of the peeling force increasing agent (for example, a silane coupling agent) contained in the adhesive composition of one Embodiment of this invention can be set so that a desired use effect may be acquired, and it is not specifically limited. The amount of the peeling force increasing agent may be, for example, 0.005 parts by mass or more per 100 parts by mass of the base polymer contained in the pressure-sensitive adhesive composition. The content of the peeling force increasing agent per 100 parts by mass of the base polymer is usually preferably 0.05 parts by mass or more, and may be 0.10 parts by mass or more, 0.20 parts by mass or more, or 0.30 parts by mass or more. The synergistic effect of peeling force can be exhibited by increase in content of a peeling force increasing agent.

In addition, depending on the mode of use of the peeling force increasing agent, if the period from room temperature until the peeling force rises with time is too short, the reworkable period becomes too short, which may cause problems such as complicated process management. can From such a viewpoint, some aspect WHEREIN: Content of the peeling force increasing agent per 100 mass parts of base polymers in an adhesive composition may be 5 mass parts or less, 3 mass parts or less may be sufficient, for example, 1 mass part or less may be sufficient, and 0.7 mass part or less (for example, 0.5 mass part or less) may be sufficient.

(crosslinking agent)

The pressure-sensitive adhesive composition of one embodiment of the present invention is mainly for the purpose of crosslinking within the pressure-sensitive adhesive layer or crosslinking between the pressure-sensitive adhesive layer and its adjacent surface, and may contain a crosslinking agent as necessary. The type of the crosslinking agent is not particularly limited, and may be selected so that the crosslinking agent exhibits an appropriate crosslinking function in the pressure sensitive adhesive layer, for example, depending on the composition of the pressure sensitive adhesive composition.

Examples of the crosslinking agent that can be used include an isocyanate-based crosslinking agent, an epoxy-based crosslinking agent, an oxazoline-based crosslinking agent, an aziridine-based crosslinking agent, a carbodiimide-based crosslinking agent, a melamine-based crosslinking agent, a urea-based crosslinking agent, a metal alkoxide-based crosslinking agent, a metal chelate-based crosslinking agent, and a metal salt-based crosslinking agent. , a hydrazine-based crosslinking agent and an amine-based crosslinking agent can be exemplified. These can be used individually by 1 type or in combination of 2 or more type.

As an isocyanate type crosslinking agent, the polyfunctional isocyanate compound more than bifunctional can be used. For example, Aromatic isocyanate, such as tolylene diisocyanate, xylene diisocyanate, polymethylene polyphenyl diisocyanate, tris (p-isocyanate phenyl) thiophosphate, diphenylmethane diisocyanate; Alicyclic isocyanate, such as isophorone diisocyanate; aliphatic isocyanates such as hexamethylene diisocyanate; and the like. Commercially available products include trimethylolpropane/tolylene diisocyanate trimer adduct (manufactured by Tosoh Corporation, trade name "Coronate L"), trimethylolpropane/hexamethylene diisocyanate trimer adduct (manufactured by Tosoh Corporation, trade name "Coronate HL"), Isocyanate adducts, such as the isocyanurate body (The Tosoh Corporation make, brand name "Coronate HX") of hexamethylene diisocyanate, etc. can be illustrated.

As the epoxy-based crosslinking agent, those having two or more epoxy groups in one molecule can be used without particular limitation. An epoxy-based crosslinking agent having 3 to 5 epoxy groups in one molecule is preferable. Specific examples of the epoxy crosslinking agent include N,N,N',N'-tetraglycidyl-m-xylenediamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, 1,6 - hexanediol diglycidyl ether, polyethylene glycol diglycidyl ether, polyglycerol polyglycidyl ether, etc. are mentioned. Commercially available epoxy-based crosslinking agents include "TETRAD-X" and "TETRAD-C" manufactured by Mitsubishi Gas Chemical, "Epiclon CR-5L" manufactured by DIC, and "Denacol EX-512" manufactured by Nagase Chemtex. ', Nissan Chemical Industry Co., Ltd. brand name "TEPIC-G", etc. are mentioned.

As the oxazoline-based crosslinking agent, one having at least one oxazoline group in one molecule can be used without particular limitation.

Examples of the aziridine-based crosslinking agent include trimethylolpropanetris[3-(1-aziridinyl)propionate], trimethylolpropanetris[3-(1-(2-methyl)aziridinylpropionate)], and the like. can be heard

As the carbodiimide-based crosslinking agent, a low-molecular compound or a high-molecular compound having two or more carbodiimide groups can be used.

In some aspects, you may use a peroxide as a crosslinking agent. Examples of the peroxide include di(2-ethylhexyl)peroxydicarbonate, di(4-t-butylcyclohexyl)peroxydicarbonate, di-sec-butylperoxydicarbonate, and t-butylperoxyneode. Canoate, t-hexylperoxypivalate, t-butylperoxypivalate, dilauroyl peroxide, di-N-octanoyl peroxide, 1,1,3,3-tetramethylbutylperoxyisobutyl Late, dibenzoyl peroxide, etc. are mentioned. Among these, di(4-t-butylcyclohexyl)peroxydicarbonate, dilauroyl peroxide, dibenzoyl peroxide, etc. are mentioned as a peroxide especially excellent in crosslinking reaction efficiency.

In addition, when a peroxide is used as the polymerization initiator, it is also possible to use the peroxide remaining without being used in the polymerization reaction for the crosslinking reaction. In that case, the residual amount of the peroxide is quantified, and when the ratio of the peroxide does not satisfy the predetermined amount, what is necessary is just to add a peroxide so that it may become a predetermined amount as needed. Quantification of the peroxide can be performed by the method described in Japanese Patent No. 4971517.

Content of a crosslinking agent (when 2 or more types of crosslinking agents are included, their total amount) is not specifically limited. From the viewpoint of realizing an adhesive that exhibits adhesive properties such as adhesive force and cohesive force in a balanced manner, the content of the crosslinking agent is usually about 5 parts by mass or less with respect to 100 parts by mass of the base polymer contained in the pressure-sensitive adhesive composition, It is preferable to set it as about 0.001-5 mass parts, It is more preferable to set it as about 0.001-4 mass parts, It is still more preferable to set it as about 0.001-3 mass parts.

Or the adhesive composition which does not contain the above-mentioned crosslinking agent may be sufficient. In the case of using a photocurable pressure-sensitive adhesive composition as the pressure-sensitive adhesive composition of one embodiment of the present invention, the pressure-sensitive adhesive composition may substantially not contain a crosslinking agent such as an isocyanate-based crosslinking agent. Here, that the pressure-sensitive adhesive composition substantially does not contain a crosslinking agent (typically an isocyanate-based crosslinking agent) means that the amount of the crosslinking agent relative to 100 parts by mass of the base polymer is less than 0.05 parts by mass (for example, less than 0.01 parts by mass). say

In order to advance a crosslinking reaction more effectively, you may use a crosslinking catalyst. Examples of the crosslinking catalyst include metal-based crosslinking catalysts such as tetra-n-butyl titanate, tetraisopropyl titanate, nashem ferric, butyltin oxide and dioctyltin dilaurate. Among them, tin-based crosslinking catalysts such as dioctyltin dilaurate are preferable.

The amount of the crosslinking catalyst used is not particularly limited. The usage-amount of the crosslinking catalyst with respect to 100 mass parts of base polymers in an adhesive composition may be about 0.0001 mass part or more and 1 mass part or less, for example, 0.001 mass part or more and 0.1 mass part or less may be sufficient, 0.005 mass part or more and 0.5 mass part or less may be

A polyfunctional monomer may be used for the pressure-sensitive adhesive composition (further, the pressure-sensitive adhesive layer) as needed. The polyfunctional monomer may be useful for purposes such as adjustment of cohesive force by being used instead of or in combination with the crosslinking agent as described above. For example, in the pressure-sensitive adhesive layer formed of the photo-curable pressure-sensitive adhesive composition, a polyfunctional monomer may be preferably used.

Examples of the polyfunctional monomer include ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, neopentyl glycol di( Meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, ethylene glycol di (meth) acrylate, 1,6-hexane Diol di (meth) acrylate, 1,12-dodecanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylol methane tri (meth) acrylate, allyl (meth) acrylate, vinyl (meth)acrylate, divinylbenzene, epoxy acrylate, polyester acrylate, urethane acrylate, butyldiol (meth)acrylate, hexyldiol di(meth)acrylate, etc. are mentioned.

Among them, trimethylolpropane tri(meth)acrylate, 1,6-hexanediol di(meth)acrylate, and dipentaerythritol hexa(meth)acrylate can be preferably used. A polyfunctional monomer can be used individually by 1 type or in combination of 2 or more type.

Although the usage-amount of a polyfunctional monomer varies with the molecular weight, the number of functional groups, etc., it is usually suitable to set it as the range of about 0.01 mass parts - 3.0 mass parts with respect to 100 mass parts of base polymers. In some aspects, the usage-amount of polyfunctional monomer with respect to 100 mass parts of base polymers may be, for example, 0.02 mass part or more, 0.1 mass part or more may be sufficient, 0.5 mass part or more, 1.0 mass part or more, or 2.0 mass parts. It may be more than a part. With an increase in the amount of the polyfunctional monomer used, higher cohesive force tends to be obtained.

On the other hand, from the viewpoint of avoiding a decrease in adhesion between the pressure-sensitive adhesive layer and the adjacent layer due to excessive cohesion improvement, the amount of the polyfunctional monomer used relative to 100 parts by mass of the base polymer may be, for example, 10 parts by mass or less, 5.0 A mass part or less may be sufficient and 3.0 mass part or less may be sufficient.

(Acrylic oligomer)

In the pressure-sensitive adhesive composition (and further, the pressure-sensitive adhesive layer) of the embodiment of the present invention, from the viewpoint of improving cohesive force and improving adhesion with a surface adjacent to the pressure-sensitive adhesive layer (for example, it may be the surface of a substrate, etc.), acrylic type Oligomers may be incorporated.

As the acrylic oligomer, it is preferable to use a polymer having a higher Tg than the Tg of the acrylic polymer.

Tg of the acrylic oligomer is not particularly limited, and may be, for example, about 20° C. or more and 300° C. or less. The Tg may be, for example, about 30°C or higher, about 40°C or higher, about 60°C or higher, about 80°C or higher, or about 100°C or higher. When the Tg of the acrylic oligomer increases, the effect of improving the cohesive force tends to increase in general.

In addition, from the viewpoint of anchoring properties to the substrate, shock absorption, etc., the Tg of the acrylic oligomer may be, for example, about 250° C. or less, about 200° C. or less, about 180° C. or less, or about 150° C. or less. In addition, Tg of an acryl-type oligomer is a value calculated based on Fox's formula similarly to Tg of the acryl-type polymer corresponding to the composition of the said monomer component.

The Mw of the acrylic oligomer may be typically greater than or equal to about 1000 and less than about 30000, preferably greater than or equal to about 1500 and less than about 10000, more preferably greater than or equal to about 2000 and less than about 5000. When Mw exists in the said range, the effect of improving cohesiveness and adhesiveness with an adjacent surface is easy to be exhibited preferably.

Mw of an acryl-type oligomer can be measured by gel permeation chromatography (GPC), and can be calculated|required as a value in terms of standard polystyrene. Specifically, it is measured under the conditions of a flow rate of about 0.5 mL/min in a tetrahydrofuran solvent using a column of TSkgelGMH-H (20) x 2 in HPLC8020 manufactured by Tosoh Corporation.

Examples of the monomer component constituting the acrylic oligomer include the above-described various (meth)acrylic acid C _1-20 alkyl esters; the above-mentioned various alicyclic hydrocarbon group-containing (meth)acrylates; various aromatic hydrocarbon group-containing (meth)acrylates described above; (meth)acrylate obtained from terpene compound derivative alcohol; (meth)acrylate monomers, such as these are mentioned. These can be used individually by 1 type or in combination of 2 or more type.

The acrylic oligomers include alkyl (meth) acrylates in which an alkyl group such as isobutyl (meth) acrylate or t-butyl (meth) acrylate has a branched structure; alicyclic hydrocarbon group-containing (meth)acrylate and aromatic hydrocarbon group-containing (meth)acrylate; It is preferable from a viewpoint of improving adhesiveness that the acrylic monomer which has a comparatively bulky structure typified by these etc. is included as a monomer unit.

In addition, in the case of employing ultraviolet rays during the synthesis of the acrylic oligomer or the preparation of the pressure-sensitive adhesive layer, a monomer having a saturated hydrocarbon group at the ester terminal is preferable from the viewpoint of hardly causing polymerization inhibition, for example, an alkyl group having a branched structure. Alkyl (meth)acrylate or saturated alicyclic hydrocarbon group containing (meth)acrylate can be used preferably.

The ratio of the (meth)acrylate monomer to the total monomer components constituting the acrylic oligomer is typically more than 50% by weight, preferably 60% by weight or more, more preferably 70% by weight or more (for example, 80% by weight or more) % by weight or more, further 90% by weight or more).

In one preferred aspect, the acrylic oligomer has a monomer composition substantially composed of only one or two or more (meth)acrylate monomers. When the monomer component includes an alicyclic hydrocarbon group-containing (meth)acrylate and (meth)acrylic acid C _1-20 alkyl ester, their weight ratio is not particularly limited, for example, in the range of 10/90 to 90/10, It can be set as the range of 20/80-80/20, the range of 70/30-30/70, etc.

As a structural monomer component of an acryl-type oligomer, in addition to said (meth)acrylate monomer, a functional group containing monomer can be used as needed. Examples of the functional group-containing monomer include a monomer having a nitrogen atom-containing heterocycle such as N-vinyl-2-pyrrolidone and N-acryloylmorpholine; amino group-containing monomers such as N,N-dimethylaminoethyl (meth)acrylate; amide group-containing monomers such as N,N-diethyl (meth)acrylamide; carboxyl group-containing monomers such as AA and MAA; Hydroxyl group-containing monomers, such as 2-hydroxyethyl (meth)acrylate; is mentioned. These functional group containing monomers can be used individually by 1 type or in combination of 2 or more type.

When a functional group-containing monomer is used, the ratio of the functional group-containing monomer to the total monomer components constituting the acrylic oligomer may be, for example, 1 wt% or more, 2 wt% or more, or 3 wt% or more, and For example, it may be 15 wt% or less, 10 wt% or less, or 7 wt% or less.

Preferred acrylic oligomers include, for example, dicyclopentanyl methacrylate (DCPMA), cyclohexyl methacrylate (CHMA), isobornyl methacrylate (IBXMA), isobornyl acrylate (IBXA), and dicyclopentanyl acrylate. Rates (DCPA, 1-adamantyl methacrylate (ADMA, 1-adamantyl acrylate (ADA)) each homopolymer, DCPMA and MMA copolymer, DCPMA and IBXMA copolymer, ADA and methyl methacrylic Copolymer of late (MMA), copolymer of CHMA and isobutyl methacrylate (IBMA), copolymer of CHMA and IBXMA, copolymer of CHMA and acryloylmorpholine (ACMO), CHMA and diethylacrylamide ( a copolymer of DEAA), a copolymer of CHMA and AA, and the like.

The acrylic oligomer can be formed by polymerizing its constituent monomer components. The polymerization method and polymerization mode are not particularly limited, and various conventionally known polymerization methods (for example, solution polymerization, emulsion polymerization, bulk polymerization, photopolymerization, radiation polymerization, etc.) can be employed in an appropriate mode. The kind of polymerization initiator (for example, azo polymerization initiator) that can be used as needed is as exemplified about the synthesis of the acrylic polymer, and the amount of polymerization initiator and the chain transfer agent (for example, mercaptans) used arbitrarily Since the amount of is appropriately set based on common technical knowledge so as to obtain a desired molecular weight, detailed description thereof will be omitted.

When the pressure-sensitive adhesive composition contains an acrylic oligomer, the content may be, for example, 0.01 parts by mass or more with respect to 100 parts by mass of the base polymer, and may be 0.05 parts by mass or more from the viewpoint of obtaining a higher effect, It is good also as 0.1 mass part or more or 0.2 mass part or more.

In addition, from the viewpoint of compatibility with the base polymer, etc., the content of the acrylic oligomer is usually preferably less than 50 parts by mass, preferably less than 30 parts by mass, more preferably 25 parts by mass or less, 10 It is good also as a mass part or less, 5 mass parts or less, or 1 mass part or less.

(Other ingredients)

The pressure-sensitive adhesive composition of one embodiment of the present invention is a range in which the effects of the present invention are not impaired, and if necessary, a tackifying resin (eg, rosin-based, petroleum-based, terpene-based, phenol-based, ketone-based, etc.) of tackifying resins), viscosity modifiers (e.g. thickeners), leveling agents, plasticizers, fillers, colorants such as pigments and dyes, stabilizers, preservatives, and anti-aging agents. It can be included as an ingredient. As for such various additives, a conventionally known additive can be used by a conventional method, and since it does not specifically characterize this invention, detailed description is abbreviate|omitted.

In addition, since the technique concerning this embodiment can exhibit favorable adhesive force without using the above-mentioned tackifying resin, content of the said tackifying resin in an adhesive composition is with respect to 100 mass parts of base polymers, for example, It is less than 10 mass parts, Furthermore, it can be set as less than 5 mass parts. The content of the tackifying resin may be less than 1 part by mass (for example, less than 0.5 parts by mass) or less than 0.1 parts by mass (0 parts by mass or more and less than 0.1 parts by mass), and the pressure-sensitive adhesive composition does not contain a tackifying resin it may not be

It is preferable that the quantity of components other than a base polymer which the adhesive composition of one Embodiment of this invention occupies in an adhesive composition from a viewpoint of a transparency improvement is restrict|limited. In the technique according to the present embodiment, the amount of components other than the base polymer in the pressure-sensitive adhesive composition is usually about 30% by weight or less, preferably about 15% by weight or less, and preferably about 12% by weight or less (for example, For example, about 10% by weight or less). The amount of components other than the base polymer in the pressure-sensitive adhesive composition according to the embodiment may be about 5% by weight or less, about 3% by weight or less, or about 1.5% by weight or less (for example, about 1% by weight or less) do. Thus, the composition in which the amount of components other than a base polymer was limited can be suitably employ|adopted with respect to the adhesive composition of this embodiment.

<Adhesive layer>

The pressure-sensitive adhesive layer of one embodiment of the present invention is formed of the pressure-sensitive adhesive composition. Fig. 2 is a schematic cross-sectional view of a configuration example of an adhesive layer according to an embodiment of the present invention.

The pressure-sensitive adhesive layer may be a cured layer of the pressure-sensitive adhesive composition. That is, this adhesive layer can be formed by providing (for example, apply|coating) an adhesive composition to a suitable surface, and performing a hardening process suitably. When two or more curing treatments (drying, crosslinking, polymerization, etc.) are performed, these can be performed simultaneously or in multiple steps.

In the pressure-sensitive adhesive composition using the partially polymerized product (polymer syrup) of the monomer component, a final copolymerization reaction is typically performed as the curing treatment described above. That is, the partial polymer is subjected to a new copolymerization reaction to form a complete polymer. For example, if it is a photocurable adhesive composition, light irradiation is performed. If necessary, curing treatment such as crosslinking and drying may be performed. For example, if it is necessary to dry the photo-curable pressure-sensitive adhesive composition (for example, in the case of a photo-curable pressure-sensitive adhesive composition in which a partial polymer of a monomer component is dissolved in an organic solvent), the photo-curing is performed after drying the composition. do it

In the pressure-sensitive adhesive composition using the complete polymer, typically, as the curing treatment, a treatment such as drying (heat drying) or crosslinking is performed as needed. In the case of a solvent-type adhesive composition to which photocurability (photocrosslinkability) was imparted by addition of a polyfunctional monomer, photocuring may be performed after drying the composition. Here, after drying the said composition, after bonding the adhesive sheet mentioned later obtained through the said drying to a to-be-adhered body may be sufficient. The pressure-sensitive adhesive sheet to be described later can be used in an embodiment in which adhesion to the adherend is performed by a method including photocuring after bonding to the adherend.

The pressure-sensitive adhesive layer having a multilayer structure of two or more layers can be produced by bonding the previously formed pressure-sensitive adhesive layers. Alternatively, the pressure-sensitive adhesive composition may be applied on the previously formed first pressure-sensitive adhesive layer, the pressure-sensitive adhesive composition may be cured, and the second pressure-sensitive adhesive layer may be formed. When the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet to be described later used as an attachment mode for photo-curing after bonding to an adherend has a multi-layer structure, the photo-curing pressure-sensitive adhesive layer includes some layers (for example, one layer) included in the multi-layer structure. ) or all layers.

Application of the said adhesive composition can be performed using conventional coaters, such as a gravure roll coater, a reverse roll coater, a kiss roll coater, a dip roll coater, a bar coater, a knife coater, and a spray coater, for example. In the pressure-sensitive adhesive sheet of the form having a base material to be described later, as a method of forming the pressure-sensitive adhesive layer on the base material, a direct method in which the pressure-sensitive adhesive composition is directly applied to the base material to form the pressure-sensitive adhesive layer may be used, and the pressure-sensitive adhesive layer formed on the release surface You may use the transcription method which transcribe|transfers to a base material.

The thickness of the pressure-sensitive adhesive layer is not particularly limited, and may be, for example, about 3 µm to 2000 µm. From the viewpoint of adhesiveness with an adherend such as step followability, in some aspects, the thickness of the pressure-sensitive adhesive layer is, for example, 5 µm or more, preferably 10 µm or more, preferably 20 µm or more, more preferably It is preferably 30 μm or more. The thickness of the pressure-sensitive adhesive layer may be 50 µm or more, may be more than 50 µm, may be 70 µm or more, may be 100 µm or more, or may be 120 µm or more.

In addition, from the viewpoint of preventing the generation of adhesive residue due to cohesive failure of the pressure-sensitive adhesive layer, in some aspects, the thickness of the pressure-sensitive adhesive layer may be, for example, 1000 µm or less, 700 µm or less, or 500 µm or less It may be, and 300 micrometers or less, 200 micrometers or less, or 170 micrometers or less may be sufficient. The technique concerning this aspect can be implemented suitably also with the form of the adhesive sheet mentioned later whose thickness of an adhesive layer is 130 micrometers or less, 90 micrometers or less, and 60 micrometers or less (for example, 40 micrometers or less). In addition, in the adhesive sheet mentioned later which has an adhesive layer which has a multilayer structure of two or more layers, the thickness of the said adhesive layer means the thickness from the adhesive surface adhered to a to-be-adhered body to the surface on the opposite side to the said adhesive surface.

<Adhesive sheet>

The adhesive sheet of one Embodiment of this invention has the said adhesive layer. The pressure-sensitive adhesive sheet of the present embodiment may be a pressure-sensitive adhesive sheet provided with a base material having an pressure-sensitive adhesive layer on one or both sides of a sheet-like substrate (support), or may be an inorganic pressure-sensitive adhesive sheet such as a form in which the pressure-sensitive adhesive layer is held on a release sheet. do. The concept of the pressure-sensitive adhesive sheet referred to herein may include those referred to as pressure-sensitive adhesive tapes, pressure-sensitive adhesive labels, pressure-sensitive adhesive films, and the like.

In addition, although the pressure-sensitive adhesive layer is typically formed continuously, the pressure-sensitive adhesive layer is not limited to this form, and the pressure-sensitive adhesive layer formed in a regular or random pattern such as dots or stripes may be used. In addition, roll shape may be sufficient as the adhesive sheet of this embodiment, and sheet shape may be sufficient as it. Alternatively, the pressure-sensitive adhesive sheet may be further processed into various shapes.

(UV absorption layer)

The pressure-sensitive adhesive sheet according to an embodiment of the present invention may have a UV absorbing layer on one side of the pressure-sensitive adhesive layer. In FIG. 3, in the adhesive sheet of one Embodiment of this invention, the schematic sectional drawing of one structural example which equips the single side|surface of an adhesive layer with a UV absorption layer is shown. The adhesive sheet 1 shown in FIG. 3 is provided with the adhesive layer 21 and the UV absorption layer 31 provided on the single side|surface of the adhesive layer. The UV absorbing layer 31 contains a UV absorbing agent such as a UV absorbing polymer.

Depending on the kind of the photooxidizing agent or photobase generator contained in the pressure-sensitive adhesive sheet, an acid or a base is generated by ultraviolet rays contained in sunlight, which may cause discoloration or discoloration of the sheet. In this case, there exists a problem that it becomes difficult to discolor or color an adhesive sheet at arbitrary timings by irradiating an active energy ray. In order to prevent such a problem, it is preferable to provide the said UV absorbing layer as a countermeasure against external light.

That is, by providing the UV absorbing layer on the side of the pressure-sensitive adhesive layer that is irradiated with sunlight, it is possible to prevent the ultraviolet rays included in sunlight from reaching the pressure-sensitive adhesive layer, and as a result, the pressure-sensitive adhesive layer is discolored by irradiation with sunlight. Or coloring can be prevented. In addition, even when a UV absorption layer is provided, it is possible to discolor or color the pressure-sensitive adhesive sheet by selecting an active energy ray not absorbed by the UV absorption layer and irradiating it at an appropriate timing.

In addition, when the UV absorption layer is laminated on the pressure-sensitive adhesive layer and then discolored or colored by irradiating an active energy ray, when the energy at which the photoacid generator and the photobase generator become active is absorbed by the UV absorption layer, the ultraviolet as activation energy is It is preferable to irradiate an active energy ray from the side opposite to the surface in which the UV absorption layer was provided in the adhesive sheet so that it may not be absorbed by a UV absorption layer.

The UV absorbing polymer used as the UV absorber can be suitably selected from polymers containing a structural unit having UV absorbing ability. Examples include 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-dodecyloxybenzophenone, 2-hydroxy-4-methoxy-5 -sulfobenzophenone, 2,4-dihydroxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, bis(2-methoxy-4-hydroxy-5-benzoylphenyl ) Methane, 2-hydroxy-4-acryloyloxybenzophenone, 2-hydroxy-4-methacryloyloxybenzophenone, 2-hydroxy-4-(2-acryloyloxy)ethoxybenzo phenone, 2-hydroxy-4-(2-methacryloyloxy)ethoxybenzophenone, 2-hydroxy-4-(2-methyl-2-acryloyloxy)ethoxybenzophenone, etc. 2-hydroxybenzophenone derivatives; 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-5'-t-butylphenyl)benzotriazole, 2-(2'-hydroxy-5' -3',5'-di-t-butylphenyl)benzotriazole, 2-(2'-hydroxy-3'-t-butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2-( 2'-Hydroxy-3'-5'-di-t-amylphenyl)benzotriazole, 2-{2'-hydroxy-3'-(3",4",5",6"-tetrahydro Phthalimidomethyl-5'-methylphenyl}benzotriazole, 2,2-methylenebis{4-(1,1,3,3-tetramethylbutyl)-6-(2H-benzotriazol-2-yl)phenol }, 2-{2'-hydroxy-5'-(methacryloyloxy)phenyl}benzotriazole, 2-[2'-hydroxy-5'-(acryloyloxy)phenyl]benzotriazole , 2-[2'-hydroxy-3'-t-butyl-5'-(methacryloyloxy)phenyl]benzotriazole, 2-[2'-hydroxy-3'-methyl-5'- (acryloyloxy)phenyl]benzotriazole, 2-{2'-hydroxy-5'-(methacryloyloxypropyl)phenyl}-5-chlorobenzotriazole, 2-[2'-hydroxyl -5'-(methacryloyloxyethyl)phenyl]benzotriazole, 2-[2'-hydroxy-5'-(acryloyloxyethyl)phenyl]benzotriazole, 2-[2'-hydro Roxy-3'-t-butyl-5'-(methacryloyloxyethyl)phenyl]benzotriazole, 2-[2'-hydroxy-3'-methyl-5'-(acryloyloxyethyl) Phenyl]benzotriazole, 2-[2'-hydroxy-5'-(methacryloyloxypropyl)phenyl]-5-chlorobenzotriazole, 2-[2'-hydroxy-5'-(acryl 2 containing royloxybutyl)phenyl]-5-methylbenzotriazole, [2-hydroxy-3-t-butyl-5-(acryloyloxyethoxycarbonylethyl)phenyl]benzotriazole, etc. -Hydroxybenzotriazole derivatives: salicylic acid derivatives such as phenyl salicylate, pt-butylphenyl salicylate, and p-octylphenyl salicylate, but are not limited thereto.

The UV-absorbing polymer preferably has a maximum absorption wavelength in the range of 300 to 400 nm.

The UV absorbing polymer is preferably a copolymer which is a reaction product of a mixture of a UV absorbing vinyl monomer and one or more copolymerizable compatible vinyl monomers, wherein the UV absorbing vinyl monomer has a structure having UV absorbing ability as described above includes units.

As the copolymerizable vinyl monomer, for example, acrylic acid, alkylacrylic acid (methacrylic acid, etc.), esters or amides derived from acrylic acid (for example, acrylamide, methacrylamide, n-butylacrylamide, t-butylacrylamide) , diacetone acrylamide, methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, t-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, Lauryl acrylate, 2-ethoxyethyl acrylate, 2-methoxyethyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, b-hydroxyl methacrylate, etc.), vinyl ester (For example, vinyl acetate, vinyl propionate, vinyl laurate, etc.), acrylonitrile, methacryloylnitrile, aromatic vinyl compounds (for example, styrene and its derivatives, such as vinyltoluene, divinylbenzene , vinylacetophenone, sulfostyrene, etc.), illaconic acid, citraconic acid, crotonic acid, vinylidene chloride, vinyl alkyl ether (eg, vinyl ethyl ether, etc.), maleic acid, N-vinyl-2-pyrrol Don, N-vinylpyridine, esters such as 2- or 4-vinylpyridine, sulfonic acids including monomers (eg, acrylamide-2,2'-dimethylpropanesulfonic acid, 2-sulfoethylmethacrylate, 3- sulfopropyl methacrylate, etc.).

Among these monomers, esters of acrylic acid, esters of methacrylic acid, and aromatic vinyl compounds are preferable.

As a specific example of a preferable comonomer, butyl acrylate; 2-ethylhexyl acrylate; 2-ethoxyethyl acrylate; 2-methoxyethyl acrylate; acrylic acid; methacrylic acid; acrylamide; 2-hydroxyethyl acrylate; vinyl acetate; styrene; N-vinyl-2-pyrrolidone; 2-sulfoethyl methacrylate and its metal salts; 2-acrylamide-2-methylpropanesulfonic acid and its metal salts are mentioned.

(Adhesive layer containing UV absorber)

The pressure-sensitive adhesive sheet of one embodiment of the present invention is provided with a pressure-sensitive adhesive layer containing a UV absorber on one side of the pressure-sensitive adhesive layer (hereinafter, also referred to as a “UV absorber-containing pressure-sensitive adhesive layer” or “UV absorbent pressure-sensitive adhesive layer”) on one side of the pressure-sensitive adhesive layer. can be In FIG. 4, in the adhesive sheet of one Embodiment of this invention, the schematic sectional drawing of one structural example which equips the single side|surface of an adhesive layer with a UV absorber containing adhesive layer is shown. The adhesive sheet 2 shown in FIG. 4 is equipped with the adhesive layer 21 and the UV absorber containing adhesive layer 41 provided on the single side|surface of the adhesive layer 21. As shown in FIG. Thereby, the external light countermeasure similar to the said UV absorption layer becomes possible.

The UV absorber contained in the said adhesive layer 41 can use the thing similar to the said UV absorber. In addition, the adhesive layer 41 containing the said UV absorber can contain the component similar to the adhesive layer of one Embodiment of this invention mentioned above.

(write)

The pressure-sensitive adhesive sheet according to some embodiments may be in the form of a pressure-sensitive adhesive sheet provided with a base material including a base material bonded to the other rear surface of the pressure-sensitive adhesive layer. In FIG. 5, in the adhesive sheet of one Embodiment of this invention, the schematic sectional drawing of one structural example in which the adhesive layer is formed on the single side|surface of a base material is shown. The adhesive sheet 3 shown in FIG. 5 is equipped with the base material 51 and the adhesive layer 21 formed on the single side|surface of the base material.

Further, as an adhesive sheet according to another embodiment, a schematic cross-sectional view of a configuration example in which adhesive layers are formed on both surfaces of the base material 51 is shown in FIG. 6 . The adhesive sheet 4 shown in FIG. 6 is provided with the base material 51, and the 1st adhesive layer 21 and the 2nd adhesive layer 22 formed on both surfaces of the base material.

The material of the base material is not particularly limited, and may be appropriately selected according to the purpose of use of the pressure-sensitive adhesive sheet, the mode of use, and the like. Non-limiting examples of the base material that can be used include a polyolefin film mainly composed of polyolefin such as polypropylene and ethylene-propylene copolymer, a polyester film composed mainly of polyester such as polyethylene terephthalate and polybutylene terephthalate, and poly Plastic films, such as a polyvinyl chloride film which has vinyl chloride as a main component; Foam sheet which consists of foams, such as a polyurethane foam, a polyethylene foam, and polychloroprene foam; Woven and nonwoven fabrics made of various fibrous materials (which may be natural fibers such as hemp and cotton, synthetic fibers such as polyester and vinylon, and semi-synthetic fibers such as acetate) alone or mixed; papers such as Japanese paper, fine paper, kraft paper, and crepe paper; metal foils such as aluminum foil and copper foil; and the like. The base material of the structure in which these were combined may be sufficient. As an example of the base material of such a composite structure, the base material of the structure in which the metal foil and the said plastic film were laminated|stacked, the plastic sheet reinforced with inorganic fibers, such as glass cloth, etc. are mentioned, for example.

As a base material of the adhesive sheet of one Embodiment of this invention, various films (henceforth a support film) can be used preferably. The support film may be a porous film, such as a foam film or a nonwoven fabric sheet, or a non-porous film, or a film having a structure in which a porous layer and a non-porous layer are laminated.

Some aspects WHEREIN: As said support film, the thing containing the resin film which can maintain shape independently (self-supporting type or non-dependence) as a base film can be used preferably. Here, the "resin film" has a non-porous structure and typically means a resin film substantially free of air bubbles (voidless). Therefore, the said resin film is a concept distinguished from a foam film and a nonwoven fabric. A single-layer structure may be sufficient as the said resin film, and the multilayer structure (for example, three-layer structure) of two or more layers may be sufficient as it.

As a resin material constituting the resin film, for example, polyester, polyolefin, polycycloolefin derived from a monomer having an aliphatic ring structure such as norbornene structure, nylon (6), nylon (66), partially aromatic polyamide Polyamide (PA), polyimide (PI), polyamideimide (PAI), polyether ether ketone (PEEK), polyether sulfone (PES), polyphenylene sulfide (PPS), polycarbonate (PC), such as ), polyurethane (PU), ethylene-vinyl acetate copolymer (EVA), polystyrene, polyvinyl chloride, polyvinylidene chloride, fluororesin such as polytetrafluoroethylene (PTFE), acrylic such as polymethyl methacrylate Resin, cellulose polymers, such as a diacetyl cellulose and triacetyl cellulose, resins, such as a vinyl butyral-type polymer, an arylate-type polymer, a polyoxymethylene-type polymer, and an epoxy-type polymer, can be used.

The said resin film may be formed using the resin material which contains individually 1 type of such resin, and may be formed using the resin material in which 2 or more types were blended. Non-stretching may be sufficient as the said resin film, and the thing extended|stretched (for example, uniaxial stretching or biaxial stretching) may be sufficient as it.

Suitable examples of the resin material constituting the resin film include polyester-based resins, PPS resins, and polyolefin-based resins. Here, the polyester-based resin refers to a resin containing polyester in a proportion exceeding 50% by weight. Similarly, the PPS resin refers to a resin containing PPS in a proportion exceeding 50% by weight, and the polyolefin-based resin refers to a resin containing a polyolefin in a proportion exceeding 50% by weight.

As the polyester-based resin, typically, a polyester-based resin containing, as a main component, a polyester obtained by polycondensing a dicarboxylic acid and a diol is used. Specific examples of the polyester resin include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), and polybutylene naphthalate.

As polyolefin resin, 1 type of polyolefin can be used individually or in combination of 2 or more types of polyolefins. The polyolefin may be, for example, an α-olefin homopolymer, a copolymer of two or more α-olefins, or a copolymer of one or two or more α-olefins with other vinyl monomers.

Specific examples include ethylene-propylene copolymers such as polyethylene (PE), polypropylene (PP), poly-1-butene, poly-4-methyl-1-pentene, and ethylene propylene rubber (EPR), and ethylene-propylene-butene copolymers. a copolymer, an ethylene-butene copolymer, an ethylene-vinyl alcohol copolymer, an ethylene-ethyl acrylate copolymer, etc. are mentioned. Both low density (LD) polyolefins and high density (HD) polyolefins can be used.

Examples of the polyolefin resin film include an unstretched polypropylene (CPP) film, a biaxially stretched polypropylene (OPP) film, a low-density polyethylene (LDPE) film, a linear low-density polyethylene (LLDPE) film, a medium-density polyethylene (MDPE) film, a high density A polyethylene (HDPE) film, a polyethylene (PE) film in which two or more types of polyethylene (PE) are blended, a PP/PE blend film in which a polypropylene (PP) is blended with a polyethylene (PE), etc. are mentioned.

As a specific example of the resin film which can be used preferably as a base material, a PET film, a PEN film, a PPS film, a PEEK film, a CPP film, and an OPP film are mentioned. A PET film, a PEN film, a PPS film, and a PEEK film are mentioned as a preferable example from a point of strength. A PET film is mentioned as a preferable example from a viewpoint of availability, dimensional stability, an optical characteristic, etc.

Known additives such as light stabilizers, antioxidants, antistatic agents, colorants (dyes, pigments, etc.), fillers, slip agents, and anti-blocking agents can be blended with the resin film as needed. The compounding quantity of an additive is not specifically limited, According to the use of an adhesive sheet, etc., it can set suitably.

The manufacturing method of a resin film is not specifically limited. For example, conventionally well-known general resin film molding methods, such as extrusion molding, inflation molding, T-die casting molding, and calender roll molding, can be employ|adopted suitably.

The substrate may be substantially constituted from such a resin film. Alternatively, the substrate may include an auxiliary layer in addition to the resin film. Examples of the auxiliary layer include an optical property adjusting layer (eg, antireflection layer), a printed layer or laminate layer for imparting a desired appearance to a substrate or adhesive sheet, an antistatic layer, a base coating layer, and a surface treatment layer such as a release layer can be heard In addition, the optical member mentioned later may be sufficient as the said base material.

The thickness of the base material is not particularly limited, and can be selected according to the purpose of use of the pressure-sensitive adhesive sheet, the mode of use, and the like. The thickness of the substrate may be, for example, 1000 µm or less, 500 µm or less, 100 µm or less, 70 µm or less, 50 µm or less, 25 µm or less, 10 µm or less, 5 micrometers or less may be sufficient. When the thickness of a base material becomes small, there exists a tendency for the flexibility of an adhesive sheet and the followability|trackability with respect to the surface shape of a to-be-adhered body to improve.

In addition, from a viewpoint of handleability, workability, etc., the thickness of a base material may be 2 micrometers or more, for example, and may be more than 5 micrometers, or more than 10 micrometers may be sufficient as it. Some aspects WHEREIN: 20 micrometers or more may be sufficient, 35 micrometers or more, and 55 micrometers or more may be sufficient as the thickness of a base material, for example.

On the surface of the base material on the side to be bonded to the pressure-sensitive adhesive layer, if necessary, a conventionally known surface such as corona discharge treatment, plasma treatment, ultraviolet irradiation treatment, acid treatment, alkali treatment, application of a base coating agent (primer), antistatic treatment, etc. Processing may be performed. Such surface treatment may be a treatment for improving the adhesion between the substrate and the pressure-sensitive adhesive layer, in other words, the anchoring property of the pressure-sensitive adhesive layer to the substrate. The composition of the primer is not particularly limited and can be appropriately selected from known ones. Although the thickness in particular of a base coating layer is not restrict|limited, Usually, about 0.01 micrometer - about 1 micrometer is suitable, and about 0.1 micrometer - about 1 micrometer is preferable.

The surface (hereinafter also referred to as the back surface) of the substrate on the opposite side to the side to be bonded to the pressure-sensitive adhesive layer may be subjected to conventionally known surface treatment such as peeling treatment, adhesion or tack improvement treatment, antistatic treatment, etc. as necessary. do. For example, the rewinding force of the adhesive sheet of the form wound on a roll can be made light by surface-treating the back surface of a base material with a peeling agent. As the peeling agent, a silicone-based peeling agent, a long-chain alkyl-based peeling agent, an olefin-based peeling agent, a fluorine-based peeling agent, a fatty acid amide-based peeling agent, molybdenum sulfide, silica powder, or the like can be used.

(Releasable Liner)

In the adhesive sheet of this embodiment, the said adhesive layer and the said UV absorber containing adhesive layer may be protected by the release liner (separator, a peeling film) until use.

As the release liner, a conventional release paper or the like can be used, and although it is not particularly limited, for example, a substrate having a release treatment layer, a low-adhesive substrate made of a fluorine-based polymer, a low-adhesive substrate made of a non-polar polymer, etc. can be used. have.

As a base material which has a peeling-treatment layer, the plastic film, paper, etc. surface-treated with peeling agents, such as a silicone type, a long-chain alkyl type, a fluorine type, and molybdenum sulfide, are mentioned, for example.

Examples of the fluorine-based polymer of the low-adhesive substrate made of the fluorine-based polymer include polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, tetrafluoroethylene/hexafluoropropylene copolymer; A chlorofluoroethylene/vinylidene fluoride copolymer etc. are mentioned.

As a nonpolar polymer of the low adhesive base material which consists of a nonpolar polymer, an olefin resin (for example, polyethylene, polypropylene, etc.) etc. are mentioned, for example. In addition, a release liner can be formed by a well-known thru|or a common method. Moreover, the thickness in particular of a release liner, etc. are not restrict|limited, either.

In the technique according to the present embodiment, the haze value of the pressure-sensitive adhesive sheet is suitably about 10% or less, and may be about 5% or less (for example, about 3% or less). The haze value is preferably 1.0% or less. Thus, a highly transparent pressure-sensitive adhesive sheet is preferable in the present invention from the viewpoint of remarkable change in appearance when discolored or colored. Less than 1.0 % may be sufficient as the haze value of an adhesive sheet, and less than 0.7 % may be sufficient as it, and 0.5 % or less (for example, 0 to 0.5 %) may be sufficient as it. These haze values related to the pressure-sensitive adhesive sheet can be suitably applied also to the haze values of the pressure-sensitive adhesive layer in the technique according to the present embodiment.

Here, "haze value" means the ratio of the diffusely transmitted light with respect to the total transmitted light when visible light is irradiated to a measurement object. Also called blur. A haze value can be represented by the following formula|equation.

Th[%]=Td/Tt×100

In the above formula, Th is haze value [%], Td is scattered light transmittance, and Tt is total light transmittance. The haze value can be measured in accordance with the method described in Examples described later. A haze value can be adjusted by selection, such as a composition and thickness of an adhesive layer, for example.

The technique concerning this embodiment can be used suitably for an electronic member use, an optical member use, a building member use, etc., for example.

Example

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described in more detail using an Example.

[Preparation of adhesive composition]

(Adhesive composition A1)

95 parts by weight of n-butyl acrylate (BA) as a monomer component, 5 parts by weight of acrylic acid (AA) as a monomer component, and 122 parts by weight of ethyl acetate as a polymerization solvent were put into a reaction vessel equipped with a cooling tube, a nitrogen introduction tube, a thermometer and a stirring device Then, 0.2 parts by weight of 2,2'-azobisisobutyronitrile (AIBN) was added as a thermal polymerization initiator and solution polymerization was performed in a nitrogen atmosphere to obtain a solution containing an acrylic polymer (1) having an Mw of 600,000.

To the solution obtained above, 6-(diethylamino)-2-[(3-trifluoromethyl)anilino]xanthene-9-spiro-3'-phthalide as a leuco dye per 100 parts by weight of the polymer component 1 part by weight of a propylene carbonate solution (trade name: CPI-100P, manufactured by San-Apro Corporation) of 50% of an active ingredient containing triarylsulfonium hexafluorophosphate as a main component as a photoacid generator 0.1 parts by weight, an epoxy-based crosslinking agent (1,3-bis(N,N-diglycidyl aminomethyl)cyclohexane, trade name: Tetrad C, manufactured by Mitsubishi Gas Chemical Co., Ltd.) was added to 0.05 parts by weight based on the solid content, and uniformly mixed to form a pressure-sensitive adhesive composition A1 was prepared.

(Adhesive composition A2)

Except having made the usage-amount of a photo-acid generator into 1 weight part per 100 weight part of said polymer components, it carried out similarly to preparation of the adhesive composition A1, and prepared the adhesive composition A2.

(Adhesive composition A3)

Except having made the usage-amount of a photo-acid generator into 5 weight part per 100 weight part of said polymer components, it carried out similarly to preparation of adhesive composition A1, and prepared adhesive composition A3.

(Adhesive composition A4)

Except having made the usage-amount of a photo-acid generator into 10 weight part per 100 weight part of said polymer components, it carried out similarly to preparation of adhesive composition A1, and prepared adhesive composition A4.

(Adhesive composition A5)

Except having made the usage-amount of a leuco dye into 10 weight part and the usage-amount of a photo-acid generator into 20 weight part per 100 weight part of said polymer components, it carried out similarly to preparation of the adhesive composition A1, and prepared the adhesive composition A5.

(Adhesive composition A6)

Preparation of pressure-sensitive adhesive composition A1 except that the type of photoacid generator was triphenylsulfonium/nonafluorobutane-1-sulfonic acid (trade name: ADEKA ARCLES SP-056, manufactured by ADEKA) and the amount used was 1 part by weight It carried out similarly, and prepared the adhesive composition A6.

(Adhesive composition A7)

Except having made the usage-amount of a photo-acid generator into 5 weight part, it carried out similarly to preparation of adhesive composition A6, and prepared adhesive composition A7.

(Adhesive composition A8)

Except not using a photo-acid generator, it carried out similarly to preparation of adhesive composition A1, and prepared adhesive composition A8.

(Adhesive composition A9)

Except not using a leuco dye, it carried out similarly to preparation of adhesive composition A2, and prepared adhesive composition A9.

<Production of adhesive sheet>

(Example 1)

A pressure-sensitive adhesive composition A1 is applied to a release film R1 (Mitsubishi Jushi Co., Ltd., MRF#38) having a thickness of 38 µm, in which one side of the polyester film is a release surface, dried at 135°C for 2 minutes, and a pressure-sensitive adhesive having a thickness of 50 µm Layer B1 was formed. By bonding to this pressure-sensitive adhesive layer B1, release film R2 (Mitsubishi Corporation, MRE#38) having a thickness of 38 µm in which one side of the polyester film is a release surface, film R2, pressure-sensitive adhesive layer B1, and release film R1 are The adhesive sheet of Example 1 laminated|stacked in this order was obtained.

(Example 2)

It replaced with the adhesive composition A1, and except the point used the adhesive composition A2, it carried out similarly to Example 1, and produced the adhesive sheet of Example 2.

(Example 3)

It replaced with the adhesive composition A1, and except the point used the adhesive composition A3, it carried out similarly to Example 1, and produced the adhesive sheet of Example 3.

(Example 4)

It replaced with the adhesive composition A1, and except the point used the adhesive composition A4, it carried out similarly to Example 1, and produced the adhesive sheet of Example 4.

(Example 5)

It replaced with the adhesive composition A1 and except the point used the adhesive composition A5, it carried out similarly to Example 1, and produced the adhesive sheet of Example 5.

(Example 6)

It replaced with the adhesive composition A1, and except the point used the adhesive composition A6, it carried out similarly to Example 1, and produced the adhesive sheet of Example 6.

(Example 7)

It replaced with the adhesive composition A1, and except the point used the adhesive composition A7, it carried out similarly to Example 1, and produced the adhesive sheet of Example 7.

(Example 8)

Peeling the release film R2 of the pressure-sensitive adhesive sheet prepared in Example 2, and bonding 100 μm of an adhesive tape (Nitto Denko Co., Ltd., product name: CS9934U) having a UV absorption function, the pressure-sensitive adhesive sheet of Example 8 having a UV absorption layer produced.

(Comparative Example 1)

It replaced with the adhesive composition A1, and except the point used the adhesive composition A8, it carried out similarly to Example 1, and produced the adhesive sheet of the comparative example 1.

(Comparative Example 2)

It replaced with the adhesive composition A1, and except the point used the adhesive composition A9, it carried out similarly to Example 1, and produced the adhesive sheet of the comparative example 2.

<Measurement of adhesive force>

(Adhesive force before UV irradiation)

For each adhesive sheet of Examples 1 to 7 and Comparative Examples 1 to 2 prepared above, the adhesive force (initial) before UV irradiation was measured. The measurement of adhesive force was performed with the following procedure.

First, each adhesive sheet was cut|disconnected so that it might become 20 mm in width and 10 cm in length, respectively, and the peeling film was peeled and removed. Then, the pressure-sensitive adhesive sheet of each example was affixed to the blue plate glass with a plate thickness of 1.2 mm by reciprocating two with a 2 kg roller. Using a tensile tester (AUTOGRAPH AGS-X, manufactured by Shimadzu Corporation), the force when peeling off at a peeling angle of 180 degrees and a peeling rate of 300 mm/min was measured as adhesive force (N/20 mm). A result is shown in Table 1.

(Adhesive strength after UV irradiation)

About each adhesive sheet of Examples 1-7 and Comparative Examples 1-2, the adhesive force (after trigger) after UV irradiation was measured. The adhesive force after UV irradiation was measured by operation similar to the above except having irradiated UV (wavelength range: 200-400 nm) after crimping|bonding an adhesive sheet to the blue plate glass of plate|board thickness 1.2 mm.

UV irradiation performed light irradiation through the said alkali glass plate in the environment of 23 degreeC and 50%RH. More specifically, 6-(diethylamino)-2-[( 3-trifluoromethyl)anilino]xanthene-9-spiro-3'-phthalide was reacted with triaryl sulfonium-PF6 salt. A result is shown in Table 1.

<Optical Characteristics Test>

In this test, coloration of the adhesive sheet by UV irradiation was evaluated according to the change of the transmittance|permeability in before and behind coloring.

Using a spectrophotometer U4100 manufactured by Hitachi High-Technologies Co., Ltd., each adhesive sheet of Examples 1 to 7 and Comparative Examples 1 and 2 was bonded to a blue plate glass having a sheet thickness of 1.2 mm, and the total light transmittance at 380 to 780 nm was obtained. Measured at a pitch of 5 nm. These measurements were performed before UV treatment and after UV treatment (UV wavelength region: 200 to 400 nm), and "change in transmittance (%)", which is a value at which the change in transmittance before and after UV treatment becomes the maximum, was obtained. The results are shown in Table 1.

<Weather resistance test>

In this test, the weather resistance with respect to the light corresponding to the ultraviolet-ray among external light by the presence or absence of a UV absorption layer was evaluated.

Using a Super Xenon Weather Meter SX75 manufactured by Suga Chemical Co., Ltd., the pressure-sensitive adhesive sheets obtained in Examples 2 and 8 were bonded to blue plate glass having a plate thickness of 1.2 mm, and an output of 120 W, light in a wavelength range of 300 to 400 nm (in external light) (corresponding to ultraviolet light) was irradiated with a super xenon lamp for 1 hour. Moreover, in Example 8 provided with a UV absorption layer, light was irradiated from the UV absorption layer side. Then, the result of having measured "change (%) of the transmittance|permeability" similarly to the above is shown in Table 2.

The transmittance|permeability of the adhesive sheets of Examples 1-7 containing a leuco dye and a photooxidation generator changed by UV irradiation. Therefore, the adhesive sheet of this invention containing a leuco dye and a photo-oxidation generator was able to be discolored or colored at arbitrary timings by irradiation of an active energy ray.

On the other hand, in the adhesive sheets of Comparative Examples 1 and 2 which do not contain a leuco dye or a photooxidation generator, the transmittance|permeability did not change most by UV irradiation.

In addition, as for the adhesive sheet of Examples 1-7 and Comparative Examples 1 and 2, the adhesive force did not change by UV irradiation in all.

In addition, the pressure-sensitive adhesive sheet of Example 8 having a UV absorbing layer on the pressure-sensitive adhesive layer containing a leuco dye and a photooxidation generator has suppressed change in transmittance compared to the pressure-sensitive adhesive sheet of Example 2 without a UV absorbing layer, Weather resistance was improved.

As mentioned above, although preferred embodiment of this invention was described, this invention is not limited to the above-mentioned embodiment, In the range which does not deviate from the scope of the present invention, various modifications and substitutions can be made to the above-described embodiment. have.

In addition, this application is to the Japanese patent application of an application on March 15, 2019 (Japanese Patent Application No. 2019-048841) and a Japanese patent application of an application on March 9, 2020 (Japanese Patent Application No. 2020-039643) basis, the contents of which are incorporated by reference during the present application.

1, 2, 3, 4: adhesive sheet
21, 22: adhesive layer
31: UV absorption layer
41: UV absorber containing adhesive layer
51: description

Claims (14)

A pressure-sensitive adhesive composition comprising a base polymer, a leuco dye, and a photoacid generator. According to claim 1,
The said leuco pigment|dye is an adhesive composition in which an absorption wavelength changes with pH. 3. The method of claim 1 or 2,
The pressure-sensitive adhesive composition comprising 0.1 to 30 parts by mass of the leuco dye per 100 parts by mass of the base polymer. 4. The method according to any one of claims 1 to 3,
The leuco dye is at least one dye selected from the group consisting of phthalide dyes and fluoran dyes, the pressure-sensitive adhesive composition. 5. The method according to any one of claims 1 to 4,
The adhesive composition containing 0.1-30 mass parts of said photo-acid generators per 100 mass parts of said base polymers. 6. The method according to any one of claims 1 to 5,
The pressure-sensitive adhesive composition, wherein the photo-acid generator is at least one compound selected from the group consisting of a sulfonium salt-based compound, an iodonium salt-based compound, and an aromatic N-oxyimide sulfonate. 7. The method according to any one of claims 1 to 6,
The base polymer comprises an acrylic polymer, the pressure-sensitive adhesive composition. 8. The method according to any one of claims 1 to 7,
A pressure-sensitive adhesive composition that is discolored by active energy ray irradiation. 8. The method according to any one of claims 1 to 7,
The pressure-sensitive adhesive composition colored by active energy ray irradiation. The adhesive layer which consists of the adhesive composition in any one of Claims 1-9. The adhesive sheet provided with the adhesive layer of Claim 10. 12. The method of claim 11,
A pressure-sensitive adhesive sheet having a UV absorbing layer on one side of the pressure-sensitive adhesive layer. 13. The method of claim 12,
The UV absorption layer is a pressure-sensitive adhesive layer containing a UV absorber, the pressure-sensitive adhesive sheet. 14. The method according to any one of claims 11 to 13,
The adhesive sheet in which the said adhesive layer is formed on the base material.

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