KR20230079062A - Resin for pigment dispersion masterbatch for adhesive, pigment dispersion masterbatch for adhesive, colored adhesive composition and adhesive sheet - Google Patents

Abstract

The present invention is a resin for a pigment dispersion masterbatch for an adhesive containing a resin (A), wherein the glass transition temperature of the resin (A) is -80 to 40 ° C, and the acid value of the resin (A) is 1 to 50 (KOHmg / g) relates to a resin for a pigment dispersion masterbatch for an adhesive.

Description

Resin for pigment dispersion masterbatch for adhesive, pigment dispersion masterbatch for adhesive, colored adhesive composition and adhesive sheet

The present invention relates to a resin for a pigment dispersion masterbatch for an adhesive, a pigment dispersion masterbatch for an adhesive, a colored adhesive composition, and an adhesive sheet.

Since members using an adhesive can be bonded and peeled off by simple operation, decorative members and decorative adhesive members in which a colored adhesive layer is provided on a base material are used in various fields.

In addition, various colors can be realized with desired density and brightness, and color fading is difficult to occur even when used outdoors or exposed to ultraviolet rays, and as a colorant having excellent weather resistance. An adhesive layer using a pigment is being studied.

Pigments have poor dispersibility compared to dyes, but it is known that the use of a dispersant improves the dispersibility of an adhesive and the uniformity of color. However, when this dispersing agent is a low-molecular compound or a surfactant, there is a risk that the dispersing agent bleeds out and the sticking stability of the pressure-sensitive adhesive decreases. In order to reduce the risk, coating the particle surfaces with a resin dispersant has been considered.

For example, Patent Document 1 has a pressure-sensitive adhesive layer composed of an adhesive composition containing an adhesive component and a pigment dispersion containing a pigment and a dispersion resin, and a colored adhesive in which the mass ratio of the pigment and the dispersion resin is set within a specific range. sheet is listed.

In Patent Document 2, a thin layer of a colored pressure-sensitive adhesive obtained by uniformly kneading and dispersing a pressure-sensitive adhesive based on polyacrylic acid ester and pigment particles coated with an acrylic resin having no active group, a transparent film having good weather resistance, and a release paper A colored pressure-sensitive adhesive sheet excellent in weather resistance obtained by being sandwiched therewith is described.

In Patent Document 3, while having a color correction function for adjusting the color tone of an optical member such as a display, thinning is possible, high adhesive strength and pigment dispersibility are maintained even when exposed to a high temperature and high humidity environment for a long period of time, and transparency For the purpose of obtaining an excellent optical pressure-sensitive adhesive, an optical pressure-sensitive adhesive comprising an adhesive resin (A) having a weight average molecular weight of 200,000 to 2,000,000, a pigment (B), a dispersing agent (C), and a curing agent (D) are listed.

Further, in the field of colored resins used for injection molding and the like, masterbatches containing pigments are used as means for coloring resins.

Japanese Unexamined Patent Publication No. 2016-98300 Japanese Unexamined Patent Publication No. 57-021473 Japanese Unexamined Patent Publication No. 2013-67782

In the prior art, since the adhesive resin, the pigment, and the dispersant are simply mixed, the dispersibility of the pigment in the adhesive resin is not sufficient, and color unevenness may occur in the appearance of the colored adhesive layer. In addition, in a high-temperature, high-humidity environment, there was a problem in adhesion stability of the adhesive, such as a decrease in adhesive strength with time.

In the field of colored resins used in injection molding, etc., masterbatches containing pigments are used, but since heat melting and kneading cannot be performed in adhesives that do not undergo a thermoforming process, measures to apply masterbatch to adhesives are did not consist

Therefore, the present invention has been made in order to solve the above problems in the prior art, and is capable of forming a pressure-sensitive adhesive layer having both pigment dispersibility and adhesion reliability, resin for pigment dispersion masterbatch for pressure-sensitive adhesive, pigment dispersion for pressure-sensitive adhesive. An object of the present invention is to provide a masterbatch, a colored pressure sensitive adhesive composition, and a pressure sensitive adhesive sheet.

As a result of the present inventors paying attention to the pigment dispersion process and examining it, by using a resin (A) having a specific glass transition temperature (Tg) and a specific acid value, the surface of the pigment is coated to form a micro masterbatch. Thus, it succeeded in obtaining a resin for a pigment dispersion masterbatch for an adhesive that facilitates dispersion in an adhesive composition.

In addition, a pigment dispersion masterbatch for an adhesive having a specific Tg and an excellent dispersibility by adjusting the content ratio of a resin for a pigment dispersion masterbatch for an adhesive containing a resin having a specific acid value and a pigment, and an excellent pigment dispersion masterbatch for an adhesive It was discovered that an adhesive layer exhibiting an external appearance and high adhesion reliability could be obtained, and the present invention was completed.

That is, this invention is as follows.

[One]

As a resin for pigment dispersion masterbatch for pressure-sensitive adhesive containing resin (A),

The glass transition temperature of the resin (A) is -80 to 40 ° C,

The acid value of the resin (A) is 1 to 50 (KOHmg / g),

Resin for pigment dispersion masterbatch for adhesives.

[2]

Including the resin for the pigment dispersion masterbatch for the adhesive described in [1] and the pigment,

A pigment dispersion masterbatch for an adhesive wherein the content of the resin (A) is 45 to 90% by mass with respect to the total mass of the pigment and the resin (A).

[3]

A colored pressure-sensitive adhesive composition comprising the pigment dispersion masterbatch for pressure-sensitive adhesives described in [2] and a base polymer.

[4]

The colored pressure-sensitive adhesive composition according to [3], wherein the base polymer is an acrylic polymer.

[5]

A pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive layer comprising the colored pressure-sensitive adhesive composition according to [3] or [4].

According to the present invention, a pressure-sensitive adhesive layer and pressure-sensitive adhesive sheet exhibiting excellent appearance and high adhesion reliability, a colored pressure-sensitive adhesive composition capable of forming the pressure-sensitive adhesive layer and pressure-sensitive adhesive sheet, a pigment dispersion masterbatch for pressure-sensitive adhesive having excellent dispersibility, and a pigment dispersion master for pressure-sensitive adhesive Resin for batches can be provided.

1 is an example of a schematic cross-sectional view of an adhesive sheet according to an embodiment of the present invention.
2 is an example of a schematic cross-sectional view of an adhesive sheet according to an embodiment of the present invention.
3 is an example of a schematic cross-sectional view of an adhesive sheet according to an embodiment of the present invention.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings, but the present invention is not limited to the following embodiments, and can be arbitrarily modified and implemented within a range not departing from the gist of the present invention. In addition, "to" which shows a numerical range is used by the meaning which includes the numerical value described before and after that as a lower limit and an upper limit.

In this specification, "adhesive" refers to a material that exhibits a flexible solid (viscoelastic material) state in a temperature range around room temperature and has a property of easily adhering to an adherend by pressure. The adhesive referred to here is generally as defined in “CADahlquist,” Adhesion: Fundamental and Practice”, McLaren & Sons, (1966) P.143”, complex tensile modulus E ^* (1Hz) <107 dyne/cm ² It may be a material having properties that satisfy (typically, a material having the above properties at 25°C).

In addition, in this specification, a "main component" refers to a component contained in excess of 50% by mass, unless otherwise specified.

In addition, in this specification, the percentage based on mass is synonymous with the percentage based on weight.

[Resin for Pigment Dispersion Masterbatch for Adhesives]

Resin for pigment dispersion masterbatch for pressure-sensitive adhesives according to the embodiment of the present invention (hereinafter sometimes simply referred to as resin for masterbatch) is a resin for pigment dispersion masterbatch for pressure-sensitive adhesive containing resin (A),

The Tg of the resin (A) is -80 to 40 ° C,

The resin (A) has an acid value of 1 to 50 (KOHmg/g).

Here, the masterbatch refers to a resin composition containing a coloring agent at a high concentration, which is used for uniformly and conveniently dispersing a colorant such as a pigment or a dispersion other than a colorant depending on the purpose in a dispersion medium for the purpose. In addition, a pigment dispersion masterbatch is a resin composition for dispersing a pigment.

The resin for the pigment dispersion masterbatch for pressure-sensitive adhesives according to the embodiment of the present invention is a resin used for the pigment dispersion masterbatch for pressure-sensitive adhesives.

As described above, conventionally, in order to disperse the pigment in the pressure-sensitive adhesive layer, the pressure-sensitive adhesive composition, the pigment, and the dispersant were simply mixed, but the dispersion of the pigment was not sufficient, resulting in uneven appearance. As a result of the present inventors paying attention to the process of dispersing the pigment and conducting an examination, by using a resin (A) having a specific Tg and a specific acid value, the masterbatch pigment can be dispersed with good dispersibility in the pressure-sensitive adhesive composition. I discovered something new. Then, the surface of the pigment was coated with the resin (A) to form a micro masterbatch, and it succeeded in obtaining a resin for a pigment dispersion masterbatch for an adhesive that facilitates dispersion in an adhesive composition.

In addition, although the adhesive composition is explained in detail later, it contains a base polymer. Conventional masterbatches containing pigments are sometimes used for coloring resins for injection molding through a heating process and a mechanical kneading process, and are designed to be infused into resins for injection molding during heat treatment, In general, a resin having a high Tg has been used. In an embodiment of the present invention, a resin (A) having a lower Tg than a resin dispersant usually used from the viewpoint of ease of mixing with a resin (base polymer) used for an adhesive, dispersibility, compatibility, solubility in a solvent, etc. By using, it was possible to obtain a resin for a pigment dispersion masterbatch for a pressure-sensitive adhesive that can be highly dispersed in the pressure-sensitive adhesive composition.

The pigment dispersion masterbatch for adhesives according to the embodiment of the present invention By mixing with the pressure-sensitive adhesive composition after coating with a resin and forming a micro masterbatch, it is possible to form a pressure-sensitive adhesive layer having excellent adhesion reliability as well as suppressing non-uniform appearance of the pressure-sensitive adhesive layer due to improved dispersibility.

<Resin (A)>

Resin (A) is preferably contained as a main component in the resin for pigment dispersion masterbatch for pressure-sensitive adhesive according to the embodiment of the present invention.

The resin (A) needs to be designed to have a glass transition temperature (Tg) of -80 to 40°C.

From the viewpoint of compatibility with the base polymer in the pressure-sensitive adhesive composition and reduction of influence on adhesive properties, the resin (A) must have a Tg of 40°C or less, preferably 20°C or less, more preferably 0°C. below From the viewpoint of handling, the resin (A) must have a Tg of -80°C or higher, preferably -70°C or higher, and more preferably -60°C or higher.

By setting the Tg of the resin (A) to 40° C. or lower, the resin (A) melts when the resin (A) and the pigment are mixed by kneading or the like, and the resin (A) is added to the pigment at the moment when the aggregation of the pigment is released. adsorption becomes easier. As a result, fine particles of the pigment are coated on the resin (A), and micro masterbatch with excellent dispersion stability is made possible.

Here, Tg of resin (A) means Tg calculated|required by Fox's formula based on the composition of the monomer component used for synthesis|combination of resin (A). As described below, Fox's formula is a relational expression between the Tg of the copolymer and the glass transition temperature (Tgi) of a homopolymer obtained by homopolymerization of each of the monomers constituting the copolymer.

1/Tg = Σ (Wi/Tgi)

Further, in the above formula of Fox, Tg is the glass transition temperature of the copolymer (unit: K), Wi is the mass fraction of the monomer i in the copolymer (copolymerization ratio on a mass basis), and Tgi is the homogeneity 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 calculation of Tg, the value described in known materials shall be used. For example, about the monomers listed below, the following values are used as the glass transition temperature of the homopolymer of the monomer.

2-Ethylhexylacrylate -70℃

isononyl acrylate -60℃

n-butyl acrylate -55℃

ethyl acrylate -22℃

methyl acrylate 8℃

Methyl methacrylate 105℃

2-hydroxyethyl acrylate -15℃

4-Hydroxybutylacrylate -40℃

vinyl acetate 32℃

acrylic acid 106℃

methacrylic acid 228℃

N-vinyl-2-pyrrolidone 54℃

Regarding the glass transition temperature of homopolymers of monomers other than those exemplified above, the values described in "Polymer Handbook" (3rd edition, John Wiley & Sons, Inc., 1989) shall be used. For a monomer for which a plurality of types of values are described in this document, the highest value is employed. When not described also in the said Polymer Handbook, the value obtained by the measuring method described in Unexamined-Japanese-Patent No. 2007-51271 shall be used.

The Tg of the resin (A) can be adjusted by appropriately changing the monomer composition (namely, the type or usage ratio of the monomers used in the synthesis of the polymer).

As long as Tg is within the above range, the type of resin (A) is not particularly limited, and those known in the art of master batches can be used. For example, it may be one or two or more of various rubber-like polymers such as acrylic polymers, rubber-based polymers, polyester-based polymers, urethane-based polymers, polyether-based polymers, silicone-based polymers, polyamide-based polymers, and fluorine-based polymers. From the viewpoints of dispersibility to the pressure-sensitive adhesive, cost, etc., an acrylic polymer or a rubber polymer is preferable, and an acrylic polymer is more preferable.

Hereinafter, the case where the resin (A) is an acrylic polymer is mainly described, but the resin (A) in the present embodiment is not intended to be limited to one composed of an acrylic polymer.

An "acrylic polymer" refers to a polymer containing a monomer unit derived from a monomer having at least one (meth)acryloyl group in one molecule as a monomer unit constituting the polymer. Hereinafter, a monomer having at least one (meth)acryloyl group in one molecule is also referred to as an "acrylic monomer". Therefore, the acrylic polymer in this specification is defined as a polymer containing a monomer unit derived from an acrylic monomer. As a typical example of the acrylic polymer, an acrylic polymer having a proportion of more than 50% by mass of the acrylic monomer among all monomer components used in the synthesis of the acrylic polymer is exemplified.

In addition, "(meth)acryloyl" is the meaning which points out acryloyl and methacryloyl comprehensively. Similarly, "(meth)acrylate" means acrylate and methacrylate, and "(meth)acryl" means acryl and methacryl respectively comprehensively.

As the acrylic polymer, for example, a polymer of a monomer raw material that contains an alkyl (meth)acrylate as a main monomer and may further contain a parent monomer copolymerizable with the main monomer is preferable. Here, the main monomer refers to a component that occupies more than 50% by mass of the monomer composition in the monomer raw material.

As an alkyl (meth)acrylate, the compound represented by following formula (1) can be used suitably, for example.

CH ₂ =C(R ¹ )COOR ² (1)

Here, R ¹ in the formula (1) is a hydrogen atom or a methyl group. Moreover, ^R2 is a C1-C20 chain|strand-shaped alkyl group. Hereinafter, the range of the number of carbon atoms may be expressed as “C _1-20 ”. From the viewpoint of adhesion stability of the pressure-sensitive adhesive, etc., it is appropriate to use an alkyl (meth)acrylate in which R ² is a chain alkyl group of C _1-14 (eg C _2-10 , typically C _4-8 ) as a main monomer do. From the standpoint of adhesive properties, it is preferable to use as a main monomer an alkyl acrylate in which R ¹ is a hydrogen atom and R ² is a C _4-8 chain alkyl group (hereinafter, simply referred to as C _4-8 alkyl acrylate).

Examples of alkyl (meth)acrylates in which R ² is a C _1-20 chain alkyl group include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, and isopropyl (meth)acrylate. , n-butyl (meth)acrylate, isobutyl (meth)acrylate, s-butyl (meth)acrylate, pentyl (meth)acrylate, isopentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, 2-ethylhexyl(meth)acrylate, octyl(meth)acrylate, isooctyl(meth)acrylate, nonyl(meth)acrylate, isononyl(meth)acrylate, decyl(meth)acrylate Acrylate, isodecyl(meth)acrylate, undecyl(meth)acrylate, lauryl(meth)acrylate, tridecyl(meth)acrylate, tetradecyl(meth)acrylate, pentadecyl(meth)acrylate , Hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate, nonadecyl (meth) acrylate, eicosyl (meth) acrylate and the like. These alkyl (meth)acrylates can be used individually by 1 type or in combination of 2 or more types. Preferred alkyl (meth)acrylates include n-butyl acrylate (BA) and 2-ethylhexyl acrylate (2EHA).

The ratio of the alkyl (meth)acrylate to the monomer component constituting the acrylic polymer is typically more than 50% by mass, for example, it can be 70% by mass or more, may be 85% by mass or more, or 90% by mass. It can be more than %. In addition, the ratio of the alkyl (meth)acrylate to the monomer component is typically less than 100% by mass, and from the viewpoint of cohesion, etc., it is usually appropriate to be 99.5% by mass or less, and 98% by mass or less (for example, For example, less than 97% by mass).

In this embodiment, it can be preferably implemented in an aspect in which the monomer component contains 50% by mass or more of C _4-8 alkyl (meth)acrylate. The ratio of C _4-8 alkyl (meth)acrylate to the monomer component may be 70% by mass or more, or 85% by mass or more (for example, 90% by mass or more). On the other hand, from the viewpoint of cohesion, etc., the ratio of C _4-8 alkyl (meth)acrylate to the monomer component is usually suitably 99.5% by mass or less, and 98% by mass or less (for example, less than 97% by mass). ) can be done.

In this embodiment, the monomer component constituting the resin (A) (eg acrylic polymer) may contain a carboxy group-containing monomer. When the monomer component contains a carboxy group-containing monomer, the dispersion state of the pigment is easily improved. In addition, it may be advantageous to improve dispersion stability. Examples of the carboxy group-containing monomer include ethylenically unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, crotonic acid, and isocrotonic acid; ethylenically unsaturated dicarboxylic acids such as maleic acid, itaconic acid, and citraconic acid, and anhydrides thereof (maleic anhydride, itaconic anhydride, etc.); and the like. These can be used individually by any 1 type or in combination of 2 types. Among them, acrylic acid (AA) and methacrylic acid (MAA) are examples of preferred carboxy group-containing monomers. AA is particularly preferred.

In the aspect in which the resin (A) is copolymerized with a carboxy group-containing monomer, the content of the carboxy group-containing monomer in the monomer component constituting the resin (A) is not particularly limited, and is, for example, 0.2% by mass of the monomer component. It can be set as above (typically 0.5 mass % or more), and it is usually suitable to set it as 1 mass % or more, good also as 2 mass % or more, good also as 3 mass % or more. By setting the content of the carboxy group-containing monomer to more than 3% by mass, a higher effect is exhibited, and an adhesive layer having more excellent holding performance is obtained. From this point of view, in one preferred aspect, the content of the carboxyl group-containing monomer can be 3.2% by mass or more of the monomer component, more preferably 3.5% by mass or more, still more preferably 4% by mass or more, and 4.5% by mass. It can be more than %. By copolymerizing such an amount of the carboxyl group-containing monomer, even when a pigment dispersion masterbatch for an adhesive described later is blended into the adhesive layer, the pigment is well dispersed in the layer, and adhesive properties such as adhesion stability can be preferably realized.

The upper limit of the content of the carboxyl group-containing monomer is not particularly limited, and may be, for example, 15% by mass or less, 12% by mass or less, or 10% by mass or less. By limiting the copolymerization ratio of the carboxyl group-containing monomer to a predetermined amount or less, even when the pigment dispersion masterbatch for an adhesive described later is blended into the adhesive layer, the pigment is well dispersed in the layer and the adhesive properties such as adhesive strength are improved. can keep In this embodiment, the content of the carboxyl group-containing monomer is 7% by mass or less (typically less than 7% by mass, for example, 6.8% by mass or less or 6.0% by mass or less) of the monomer component. there is.

A parent monomer copolymerizable with alkyl (meth)acrylate as a main monomer can be useful for introducing a crosslinking point into an acrylic polymer or increasing the cohesive force of the acrylic polymer. As a parent monomer, for example, the following functional group-containing monomers (however, the above-mentioned carboxy group-containing monomers are not included) can be used individually by 1 type or in combination of 2 or more types.

Hydroxyl group-containing monomers: for example 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate hydroxyalkyl (meth)acrylates such as the like; unsaturated alcohols such as vinyl alcohol and allyl alcohol; Polypropylene glycol mono(meth)acrylate.

Amide group-containing monomers: for example (meth)acrylamide, N,N-dimethyl (meth)acrylamide, N-butyl (meth)acrylamide, N-methylol (meth)acrylamide, N-methylol propane ( Meth)acrylamide, N-methoxymethyl(meth)acrylamide, N-butoxymethyl(meth)acrylamide.

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

Monomers having an epoxy group: eg glycidyl (meth)acrylate, methylglycidyl (meth)acrylate, allyl glycidyl ether.

Cyano group-containing monomers: eg acrylonitrile, methacrylonitrile.

Keto group-containing monomers: eg diacetone (meth)acrylamide, diacetone (meth)acrylate, vinylmethylketone, vinylethylketone, allylacetoacetate, vinylacetoacetate.

Monomers having nitrogen atom-containing rings: for example N-vinyl-2-pyrrolidone, N-methylvinylpyrrolidone, N-vinylpyridine, N-vinylpiperidone, N-vinylpyrimidine, N-vinylpipette Razine, N-vinylpyrazine, N-vinylpyrrole, N-vinylimidazole, N-vinyloxazole, N-vinylmorpholine, N-vinylcaprolactam, N-(meth)acryloylmorpholine.

Alkoxysilyl group-containing monomers: eg 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropyltriethoxysilane, 3-(meth)acryloxypropylmethyldimethoxysilane, 3- (meth)acryloxypropylmethyldiethoxysilane.

When the monomer component constituting the acrylic polymer contains the functional group-containing monomer as described above, the content of the functional group-containing monomer in the monomer component is not particularly limited. From the viewpoint of appropriately exhibiting the effect of use of the functional group-containing monomer, the content of the functional group-containing monomer in the monomer component can be, for example, 0.1% by mass or more, and is usually suitably 0.5% by mass or more. and may be 1% by mass or more. In addition, from the viewpoint of making it easy to balance the compatibility with the base polymer used in the pressure-sensitive adhesive composition and the dispersion performance in relation to the main monomer or the carboxyl group-containing monomer, the content of the functional group-containing monomer in the monomer component is usually, It is appropriate to set it as 40 mass % or less, and it is preferable to set it as 20 mass % or less, and it is good also considering it as 10 mass % or less (eg 5 mass % or less). The technology disclosed herein can also be preferably carried out in an embodiment in which the monomer component does not substantially contain a functional group-containing monomer (for example, in an embodiment in which the monomer component is substantially composed only of an alkyl (meth)acrylate and a carboxyl group-containing monomer). there is. Here, the fact that the monomer component does not substantially contain a functional group-containing monomer means that the functional group-containing monomer is not used at least intentionally, for example, 0.05% by mass or less (typically 0.01% by mass or less) of the functional group-containing monomer. The unintentional inclusion of is permissible. The acrylic polymer having such a monomer composition may be easily dispersed in a pigment dispersing masterbatch for an adhesive described later.

The monomer component constituting the acrylic polymer may contain other copolymerization components other than the parent monomer described above for the purpose of improving cohesive force or the like. Examples of other copolymerization components include vinyl ester monomers such as vinyl acetate, vinyl propionate, and vinyl laurate; Aromatic vinyl compounds, such as styrene, substituted styrene ((alpha)-methylstyrene etc.), and vinyltoluene; cycloalkyl (meth)acrylates such as cyclohexyl (meth)acrylate, cyclopentyl (meth)acrylate, and isobornyl (meth)acrylate; Aryl(meth)acrylates (eg phenyl(meth)acrylate), aryloxyalkyl(meth)acrylates (eg phenoxyethyl(meth)acrylate), arylalkyl(meth)acrylates (eg aromatic ring-containing (meth)acrylates such as benzyl (meth)acrylate); olefinic monomers such as ethylene, propylene, isoprene, butadiene, and isobutylene; chlorine-containing monomers such as vinyl chloride and vinylidene chloride; isocyanate group-containing monomers such as 2-(meth)acryloyloxyethyl isocyanate; alkoxy group-containing monomers such as methoxyethyl (meth)acrylate and ethoxyethyl (meth)acrylate; vinyl ether monomers such as methyl vinyl ether and ethyl vinyl ether; Two or more (for example, three or more) polymerizable functional groups (for example, (meth)acryloyl) in one molecule, such as 1,6-hexanedioldi(meth)acrylate and trimethylolpropane tri(meth)acrylate a polyfunctional monomer having a divalent group); and the like.

The amount of these other copolymerization components is not particularly limited as long as it is appropriately selected according to the purpose and use, and from the viewpoint of appropriately exhibiting the effect of use, it is usually appropriate to be 0.05% by mass or more, and to be 0.5% by mass or more. You can do it. In addition, from the viewpoint of making it easy to balance the adhesive performance, the content of other copolymerization components in the monomer component is usually suitably 20% by mass or less, and 10% by mass or less (for example, 5% by mass or less). can be done with In this embodiment, it can be preferably implemented also in an aspect in which the monomer component does not substantially contain other copolymerization components. Here, the fact that the monomer component does not substantially contain other copolymerization components means that other copolymerization components are not used at least intentionally, and the unintentional inclusion of other copolymerization components, for example, 0.01% by mass or less, is acceptable. can The acrylic polymer having such a monomer composition may be easily dispersed in a pigment dispersing masterbatch for an adhesive described later.

The method for obtaining the acrylic polymer is not particularly limited, and various polymerization methods known as methods for synthesizing acrylic polymers, such as solution polymerization, emulsion polymerization, bulk polymerization, suspension polymerization, and photopolymerization, can be appropriately employed. For example, a solution polymerization method can be preferably employed. The polymerization temperature at the time of polymerization can be appropriately selected depending on the type of monomer and solvent used, the type of polymerization initiator, etc., and can be, for example, 20°C to 170°C (typically 40°C to 140°C). .

The solvent (polymerization solvent) used for solution polymerization can be appropriately selected from conventionally known organic solvents. For example, aromatic compounds (typically aromatic hydrocarbons) such as toluene; Acetate esters, such as ethyl acetate; aliphatic or alicyclic hydrocarbons such as hexane and cyclohexane; halogenated alkanes such as 1,2-dichloroethane; lower alcohols such as isopropyl alcohol (for example, monohydric alcohols having 1 to 4 carbon atoms); ethers such as tert-butyl methyl ether; Any one solvent selected from ketones such as methyl ethyl ketone or a mixed solvent of two or more can be used.

The initiator used for polymerization can be appropriately selected from conventionally known polymerization initiators depending on the type of polymerization method. For example, one or two or more azo polymerization initiators such as 2,2'-azobisisobutyronitrile (AIBN) can be preferably used. Other examples of the polymerization initiator include persulfates such as potassium persulfate; peroxide-based initiators such as benzoyl peroxide and hydrogen peroxide; substituted ethane-based initiators such as phenyl-substituted ethane; Aromatic carbonyl compounds etc. are mentioned. Another example of the polymerization initiator is a redox initiator obtained by combining a peroxide and a reducing agent. These polymerization initiators can be used individually by 1 type or in combination of 2 or more types. The usage amount of the polymerization initiator may be a normal usage amount, and can be selected, for example, in the range of 0.005 to 1 part by mass (typically 0.01 to 1 part by mass) with respect to 100 parts by mass of the monomer component.

According to the above polymerization, a polymerization reaction solution in which the resin (A) is dissolved in an organic solvent is obtained. The pressure-sensitive adhesive layer in the present embodiment may contain a resin (A) solution obtained by subjecting the polymerization reaction liquid or the reaction liquid to an appropriate post-treatment. As said resin (A), what desolvated the above polymerization reaction liquid can be used. Alternatively, a resin (A) synthesized by a polymerization method other than solution polymerization (for example, emulsion polymerization, photopolymerization, bulk polymerization, etc.) may be used as it is.

The weight average molecular weight (Mw) of the resin (A) (preferably, an acrylic polymer) in the technique disclosed herein is not particularly limited, and may be, for example, in the range of 10×10 ⁴ to 500×10 ⁴ . From the viewpoint of dispersibility, the Mw of the resin (A) is 30×10 ⁴ to 200×10 ⁴ (more preferably 45×10 ⁴ to 150×10 ⁴ , typically 65×10 ⁴ to 130×10 ⁴ ). It is preferable to be in the range of Here, Mw means the standard polystyrene conversion value obtained by GPC (Gel Permeation Chromatography). As a GPC apparatus, the model name "HLC-8320GPC" (column: TSKgelGMH-H(S), manufactured by Tosoh Corporation) can be used, for example.

The acid value of the resin (A) in the embodiment of the present invention is required to be designed to be 1 KOHmg/g to 50 KOHmg/g. From the viewpoint of improving the dispersion stability of the pigment, it is preferably 5 KOHmg/g or more, and more preferably 10 KOHmg/g or more. Further, from the viewpoint of preventing corrosion of the adherend when the adhesive layer containing the resin for the pigment dispersion masterbatch for the adhesive according to the embodiment of the present invention is adhered to the adherend, it is preferably 50 KOHmg / g or less, and 30 KOHmg / It is more preferable that it is g or less, and 20 KOHmg/g or less is still more preferable.

In this embodiment, the acid value of resin (A) can employ|adopt the value measured by the potentiometric titration method prescribed|regulated by JISK0070:1992.

For example, in the above acrylic polymer, the acid value is the number of mg of potassium hydroxide required to neutralize the carboxylic acid in 1 g of the acrylic polymer.

[Pigment dispersion masterbatch for adhesive]

The pigment dispersion masterbatch for pressure-sensitive adhesives according to the embodiment of the present invention is used for pressure-sensitive adhesives, and is a masterbatch for dispersing pigments in the pressure-sensitive adhesive.

By using the pigment dispersion masterbatch for pressure-sensitive adhesives according to the embodiment of the present invention for coloring the pressure-sensitive adhesive, excellent pigment dispersibility is obtained and an pressure-sensitive adhesive layer with high adhesion reliability is obtained.

The pigment dispersion masterbatch for pressure-sensitive adhesives according to the embodiment of the present invention contains a resin for pigment dispersion masterbatch for pressure-sensitive adhesives and a pigment,

The content of the resin (A) is 45 to 90% by mass with respect to the total mass of the pigment and the resin (A).

The content of the resin (A) relative to the total mass of the pigment and the resin (A) is preferably 45% by mass or more from the viewpoint of facilitating application of shear during kneading of the pigment and the resin (A) and disintegration of the pigment, and 50 It is more preferable that it is mass % or more, and it is still more preferable that it is 60 mass % or more. Further, from the viewpoint of kneading the pigment and the resin (A) and adjusting the viscosity during disintegration of the pigment, it is preferably 90% by mass or less, more preferably 85% by mass or less, and even more preferably 80% by mass or less.

In the pigment dispersion masterbatch for pressure-sensitive adhesive according to the embodiment of the present invention, the surface of the pigment is coated with the resin (A) in the process of dispersing the pigment in the resin (A), and the shape is not particularly limited. ) may be in a solid state such as powdery or granular form or in a slurry form. Conventional masterbatches are solid at room temperature, but in the pigment dispersion masterbatch for adhesives according to the embodiment of the present invention, since the Tg of resin (A) is lower than that of the resin used in conventional masterbatches, at room temperature It can be in the form of a slurry. It is preferable in the form of a slurry because the dispersibility in the pressure-sensitive adhesive composition is improved.

(Pigment)

The type of pigment used in this embodiment is not particularly limited, and both organic and inorganic pigments can be used.

Examples of organic pigments include azo pigments such as azo lake pigments, insoluble monoazo pigments, insoluble disazo pigments, condensed azo pigments, and chelated azo pigments; polycyclic pigments such as phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, thioindigo pigments, isoindolinone pigments, and quinophthalone pigments; chelates such as basic dye chelates and acid dye chelates; nitro pigments; A nitroso pigment etc. are mentioned. These can be used individually or in mixture of 2 or more types.

Examples of inorganic pigments include titanium oxide, iron oxide, iron oxide, chromium oxide, Prussian blue, ultramarine blue, molybdenum red, iron black, and yellow lead. These can be used individually or in mixture of 2 or more types.

Especially, considering light resistance, an isoindolinone pigment, a quinacridone pigment, a condensed azo pigment, a phthalocyanine pigment, a quinophthalone pigment, and an anthraquinone pigment are used suitably.

Specific examples of organic pigments include, for example, Pigment Yellow 1 (Color Index (hereinafter referred to as C.I.) 11680), Pigment Yellow 3 (C.I.11710), Pigment Yellow 14 (C.I.21095), Pigment Yellow 17 (C.I.21105), Pigment Yellow 42 (C.I.77492), Pigment Yellow 74 (C.I.11741), Pigment Yellow 83 (C.I.21108), Pigment Yellow 93 (C.I.20710), Pigment Yellow 98 (C.I.11727), Pigment Yellow 109 (C.I.56284), Pigment Yellow 110 (C.I.56280), Pigment Yellow 128 (C.I.20037), Pigment Yellow 129 (C.I.48042), Pigment Yellow 138 (C.I.56300), Pigment Yellow 139 (C.I.56298), Pigment Yellow 147 (C.I.60645), Pigment Yellow 150 (C.I.12764), Pigment Yellow 154 (C.I.11781), Pigment Yellow 155 (C.I.200310), Pigment Yellow 180 (C.I.21290), Pigment Yellow 185 (C.I.56280), Pigment Yellow 199 (C.I.653200), Pigment Orange 5 (C.I.12075), Pigment・Orange 13 (C.I.21110), Pigment Orange 16 (C.I.21160), Pigment Orange 34 (C.I.21160), Pigment Orange 43 (C.I.71105), Pigment Orange 61 (C.I.11265), Pigment Orange 71 (C.I.561200), Pigment Red 5 (C.I.12490), Pigment Red 8 (C.I.12335), Pigment Red 17 (C.I.12390), Pigment Red 22 (C.I.12315), Pigment Red 48:2 (C.I.15865:2), Pigment Red 112 (C.I.12370), Pigment Red 122 (C.I.73915), Pigment Red 170 (C.I.12475), Pigment Red 176 (C.I.12515) ), Pigment Red 177 (C.I.65300), Pigment Red 178 (C.I.71155), Pigment Red 179 (C.I.711 30), Pigment Red 185 (C.I.12516), Pigment Red 202 (C.I. 73907), Pigment Red 208 (C.I.12514), Pigment Red 254 (C.I.56110), Pigment Red 255 (C.I.561050), Pigment Red 264, Pigment Red 272 (C.I.561150), Pigment Pigment Violet 19 (C.I.73900), Pigment Violet 23 (C.I.51319), Pigment Blue 15:1 (C.I.74160), Pigment Blue 15:3 (C.I.74160), Pigment Blue 15:4 (C.I.74160), Pigment Blue 60 (C.I.69800), Pigment Green 7 (C.I.74260), Pigment Green 36 (C.I.74265), etc., and one type or a mixture of two or more types is preferable. .

As specific examples of the inorganic pigment, for example, Pigment Yellow 42 (C.I.77492), Pigment White 6 (C.I.77891), Pigment Blue 27 (C.I.77510), Pigment Blue 29 (C.I.77007), Pigment Ment Black 7 (C.I. 77266) etc. are mentioned, and the 1 type or the mixture of 2 or more types is preferable.

In particular, considering color and coloring strength, Pigment Yellow 74 (C.I.11741), Pigment Yellow 109 (C.I.56284), Pigment Yellow 110 (C.I.56280), Pigment Yellow 128 (C.I.20037), Pigment Yellow 128 (C.I.20037), Pigment Yellow 138 (C.I.56300), Pigment Yellow 150 (C.I.12764), Pigment Yellow 155 (C.I.200310), Pigment Yellow 180 (C.I.21290), Pigment Green 7 (C.I.74260), Pigment Pigment Green 36 (C.I.74265), Pigment Red 122 (C.I.73915), Pigment Red 177 (C.I.65300), Pigment Red 202 (C.I.73907), Pigment Red 254 (C.I.56110), Pigment Pigment Violet 19 (C.I.73900), Pigment Violet 23 (C.I.51319), Pigment Blue 15:1 (C.I.74160), Pigment Blue 15:3 (C.I.74160), Pigment Blue 15:4 (C.I.74160), Pigment Blue 15:6 (C.I.74160), Pigment Blue 60 (C.I.69800), Pigment Black 7 (C.I.77266), etc. are preferable.

As the green pigment, it is selected from the group consisting of Pigment Green 7 (C.I.74260), Pigment Green 36 (C.I.74265), Pigment Yellow 138 (C.I.56300), and Pigment Yellow 150 (C.I.12764). One or more types of pigments may be suitably used.

As a blue pigment, the pigment of Pigment Blue 15:6 (C.I.74160) and/or Pigment Violet 23 (C.I.51319) can be used suitably.

The pigment may be in the form of powder, granules, or wet cake or slurry.

In this embodiment, the average particle diameter of a pigment is not specifically limited. The lower limit of the average particle diameter of the pigment may be, for example, 10 nm or more, 50 nm or more, 100 nm or more, or 150 nm or more, from the viewpoint of ease of handling. The upper limit of the average particle diameter of the pigment may be, for example, 500 nm or less, 300 nm or less, 250 nm or less, or 200 nm or less from the viewpoint of optical properties such as haze of the colored pressure sensitive adhesive.

The average particle diameter of the above-mentioned pigment refers to the volume average particle diameter, and specifically, the particle diameter at 50% of the integrated value (50% volume average particle diameter; hereinafter sometimes abbreviated as D ₅₀ ). As the measuring device, for example, "Microtrac MT3000II", a product name of Microtrac Bell Co., Ltd., or an equivalent product thereof can be used.

Various additives such as a plasticizer, a lubricant, an antioxidant, and an antistatic agent may be added to the pigment dispersion masterbatch for an adhesive according to an embodiment of the present invention, if necessary.

The method for producing the pigment dispersion masterbatch for pressure-sensitive adhesive according to the embodiment of the present invention is not particularly limited. For example, using a three roll mill, a Banbury mixer, a twin screw extruder, a kneader, etc., the resin (A) and the pigment are kneaded and kneading and dispersing, in which the pigment is coated while being dispersed in the resin (A). The temperature at the time of dispersion is usually 100 to 180°C, and the dispersion time is usually 1 minute to 1 hour.

The pigment dispersion masterbatch for pressure-sensitive adhesives according to the embodiment of the present invention is used for pressure-sensitive adhesives, and a colored pressure-sensitive adhesive composition can be obtained by dispersing the pigment dispersion masterbatch for pressure-sensitive adhesives in the pressure-sensitive adhesive composition.

Hereinafter, a colored pressure-sensitive adhesive composition containing a pigment dispersion masterbatch for pressure-sensitive adhesive according to an embodiment of the present invention will be described.

[Colored pressure-sensitive adhesive composition]

The colored pressure-sensitive adhesive composition according to the embodiment of the present invention contains a pigment dispersion masterbatch for pressure-sensitive adhesive and a base polymer.

The colored pressure-sensitive adhesive composition may be a colored pressure-sensitive adhesive composition in which a pigment dispersion masterbatch for pressure-sensitive adhesive is added to the pressure-sensitive adhesive composition containing a base polymer.

In this embodiment, the addition form of the pigment dispersion masterbatch for pressure-sensitive adhesive to the pressure-sensitive adhesive composition is not particularly limited. For example, the pigment dispersion masterbatch for pressure-sensitive adhesive may be added directly to the pressure-sensitive adhesive composition, or may be added to the pressure-sensitive adhesive composition in the form of a dispersion in which the pigment dispersion masterbatch for pressure-sensitive adhesive is dispersed in a dispersion medium.

By dispersing the pigment dispersion masterbatch for pressure-sensitive adhesive in a wet manner using a dispersion medium, the dispersibility when added to the pressure-sensitive adhesive composition is increased by being in a solvated state with the dispersion medium.

When the pigment dispersion masterbatch for an adhesive is used as a dispersion in a state of being dispersed in a dispersion medium, the median diameter of the pigment particles in the dispersion is preferably 10 nm or more, more preferably 30 nm or more, and 50 nm, from the viewpoint of the viscosity of the dispersion, etc. More than that is more preferable. Further, from the viewpoint of productivity such as avoidance of filter clogging in the colored pressure sensitive adhesive manufacturing process, it is preferably 10 μm or less, more preferably 3 μm or less, and still more preferably 1 μm or less.

For example, as a median diameter measurement method, measurement can be performed using a laser diffraction/scattering type particle size distribution analyzer LA-950 (manufactured by Horiba Seisakusho) using ethyl acetate as a dispersion medium. By calculating and measuring the relative refractive index from the respective refractive indices of ethyl acetate and the pigment to be used, the measurement can be performed for the dispersed particles of the pigment in the dispersion. From the measurement result, the median diameter of the dispersed particles of the pigment in the dispersion is obtained.

The dispersion medium constituting the dispersion is not particularly limited, and water (ion-exchanged water, reverse osmosis water, distilled water, etc.) or various organic solvents (alcohols such as ethanol; ketones such as acetone; butyl cellosolve, propylene glycol monomethyl ether) ethers such as acetate; esters such as ethyl acetate; aromatic hydrocarbons such as toluene; mixed solvents thereof); and aqueous mixed solvents of water and the above organic solvents. The dispersion liquid may contain a dispersing agent described later. By mixing the dispersion into the pressure-sensitive adhesive composition, the colored pressure-sensitive adhesive composition contains a pigment dispersion masterbatch for pressure-sensitive adhesive and a base polymer, and may also contain additives such as a dispersant described later as optional components.

The compounding quantity of the pigment dispersion masterbatch for adhesives in a colored adhesive composition is not specifically limited. Usually, it is appropriate to set it as 0.5 parts by mass or more with respect to 100 parts by mass of the base polymer, and from the viewpoint of light-shielding properties, it is preferably 1.0 parts by mass or more, more preferably 2.0 parts by mass or more, still more preferably 3.0 parts by mass. part or more (for example, 4.0 parts by mass or more).

In addition, from the viewpoint of suppressing the decrease in adhesive properties that may occur due to the blending of the pigment dispersion master batch for adhesive, the upper limit of the blending amount of the pigment dispersion master batch for adhesive is 20 parts by mass or less with respect to 100 parts by mass of the base polymer. It is preferably 10 parts by mass or less, more preferably 8 parts by mass or less, still more preferably 6 parts by mass or less.

(base polymer)

The "base polymer" in the present embodiment refers to the main component of the rubber-like polymer contained in the pressure-sensitive adhesive. A rubbery polymer refers to a polymer that exhibits rubber elasticity in a temperature range around room temperature.

In this embodiment, the type of base polymer is not particularly limited, and those known in the field of pressure-sensitive adhesives can be used. For example, one or two or more of various rubbery polymers such as acrylic polymers, rubber polymers, polyester polymers, urethane polymers, polyether polymers, silicone polymers, polyamide polymers, and fluorine polymers are used as the base polymer. may include From the standpoint of adhesive performance or cost, it is preferable to include an acrylic polymer or a rubber polymer as the base polymer. Among them, it is more preferable that the base polymer is an acrylic polymer from the viewpoint of the dispersibility of the pigment dispersion masterbatch for pressure-sensitive adhesive. Hereinafter, although the adhesive composition containing an acrylic polymer as a base polymer is mainly demonstrated, it is not intended to limit the adhesive composition in this embodiment to what was comprised by the acrylic polymer.

As the acrylic polymer, for example, a polymer of a monomer raw material that contains an alkyl (meth)acrylate as a main monomer and may further contain a parent monomer copolymerizable with the main monomer is preferable. Here, the main monomer refers to a component that occupies more than 50% by mass of the monomer composition in the monomer raw material.

As an alkyl (meth)acrylate, the compound represented by following formula (1) can be used suitably, for example.

CH ₂ =C(R ¹ )COOR ² (1)

Here, R ¹ in the formula (1) is a hydrogen atom or a methyl group. Moreover, ^R2 is a C1-C20 chain|strand-shaped alkyl group. Hereinafter, the range of the number of carbon atoms may be expressed as “C _1-20 ”. From the viewpoint of adhesion stability of the pressure-sensitive adhesive, etc., it is appropriate to use alkyl (meth)acrylate as the main monomer, wherein R ² is a chain alkyl group of C _1-14 (eg C _2-10 , typically C _4-8 ) do. From the standpoint of adhesive properties, it is preferable to use as a main monomer an alkyl acrylate in which R ¹ is a hydrogen atom and R ² is a C _4-8 chain alkyl group (hereinafter, simply referred to as C _4-8 alkyl acrylate).

Examples of alkyl (meth)acrylates in which R ² is a C _1-20 chain alkyl group include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, and isopropyl (meth)acrylate. , n-butyl (meth)acrylate, isobutyl (meth)acrylate, s-butyl (meth)acrylate, pentyl (meth)acrylate, isopentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, 2-ethylhexyl(meth)acrylate, octyl(meth)acrylate, isooctyl(meth)acrylate, nonyl(meth)acrylate, isononyl(meth)acrylate, decyl(meth)acrylate Acrylate, isodecyl(meth)acrylate, undecyl(meth)acrylate, lauryl(meth)acrylate, tridecyl(meth)acrylate, tetradecyl(meth)acrylate, pentadecyl(meth)acrylate , Hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate, nonadecyl (meth) acrylate, eicosyl (meth) acrylate and the like. These alkyl (meth)acrylates can be used individually by 1 type or in combination of 2 or more types. As preferred alkyl (meth)acrylates, n-butylacrylate (BA) and 2-ethylhexylacrylate (2EHA) are exemplified.

The ratio of the alkyl (meth)acrylate to the monomer component constituting the acrylic polymer is typically more than 50% by mass, for example, it can be 70% by mass or more, may be 85% by mass or more, or 90% by mass. It can be more than %. In addition, the ratio of the alkyl (meth)acrylate to the monomer component is typically less than 100% by mass, and from the viewpoint of cohesion, etc., it is usually appropriate to be 99.5% by mass or less, and 98% by mass or less (for example, For example, less than 97% by mass).

In this embodiment, it can be preferably implemented in an aspect in which the monomer component contains 50% by mass or more of C _1-4 alkyl (meth)acrylate. The ratio of C _1-4 alkyl (meth)acrylate to the monomer component may be 70% by mass or more, or 85% by mass or more (for example, 90% by mass or more). On the other hand, from the viewpoint of cohesion, etc., the ratio of C _1-4 alkyl (meth)acrylate to the monomer component is usually suitably 99.5% by mass or less, and 98% by mass or less (for example, less than 97% by mass). ) can be done.

In this embodiment, the monomer component is preferably implemented in an aspect containing 50% by mass or more (for example, 70% by mass or more, or 85% by mass or more, or 90% by mass or more) of C _2-4 alkyl acrylate It can be. As specific examples of C _2-4 alkyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, n-butyl acrylate (BA), isobutyl acrylate, s-butyl acrylate and t-butyl acrylate can be heard C _2-4 alkyl acrylate can be used individually by 1 type or in combination of 2 or more types. According to this aspect, it is easy to realize the adhesive sheet with good adhesion to the adherend. On the other hand, from the viewpoint of obtaining good cohesion, etc., the ratio of C _1-4 alkyl (meth)acrylate to the monomer component is usually suitably 99.5% by mass or less, and 98% by mass or less (for example, 97% by mass). less than %).

In another aspect, the monomer component also contains 50% by mass or more (for example, 70% by mass or more, or 85% by mass or more, or 90% by mass or more) of C _5-20 alkyl (meth)acrylate. can be carried out. As C _5-20 alkyl (meth)acrylate, C _6-14 alkyl (meth)acrylate is preferable. In one aspect, C _6-10 alkyl acrylate (eg C _8-10 alkyl acrylate) can be preferably employed. From the viewpoint of obtaining good cohesion, etc., the ratio of C _5-20 alkyl (meth)acrylate to the monomer component is usually suitably 99.5% by mass or less, and 98% by mass or less (for example, less than 97% by mass). ) can be done.

In this embodiment, the monomer component constituting the base polymer (eg acrylic polymer) may contain a carboxy group-containing monomer. When the monomer component contains a carboxyl group-containing monomer, it becomes easier to obtain an adhesive layer exhibiting excellent adhesion reliability. Examples of the carboxy group-containing monomer include ethylenically unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, crotonic acid, and isocrotonic acid; ethylenically unsaturated dicarboxylic acids such as maleic acid, itaconic acid, and citraconic acid, and anhydrides thereof (maleic anhydride, itaconic anhydride, etc.); and the like. These can be used individually by any 1 type or in combination of 2 types. Among them, acrylic acid (AA) and methacrylic acid (MAA) are examples of preferred carboxy group-containing monomers. AA is particularly preferred.

In the aspect in which the carboxyl group-containing monomer is copolymerized with the base polymer, the content of the carboxy group-containing monomer in the monomer component constituting the base polymer is not particularly limited, and is, for example, 0.2% by mass or more (typically can be 0.5% by mass or more), and it is usually appropriate to set it as 1% by mass or more, good as 2% by mass or more, good also as 3% by mass or more. By setting the content of the carboxy group-containing monomer to more than 3% by mass, a higher effect is exhibited, and an adhesive layer having more excellent adhesion reliability is obtained. From this point of view, in one preferred aspect, the content of the carboxyl group-containing monomer can be 3.2% by mass or more of the monomer component, more preferably 3.5% by mass or more, still more preferably 4% by mass or more, and 4.5% by mass. It can be more than %. By copolymerizing such an amount of the carboxy group-containing monomer, even when the pigment dispersion masterbatch for the pressure-sensitive adhesive is blended into the pressure-sensitive adhesive layer, the pigment is well dispersed in the layer, and adhesive properties such as adhesion reliability can be preferably realized.

The upper limit of the content of the carboxyl group-containing monomer is not particularly limited, and may be, for example, 15% by mass or less, 12% by mass or less, or 10% by mass or less. By limiting the copolymerization ratio of the carboxyl group-containing monomer to a predetermined amount or less, even when the pigment dispersion masterbatch for the pressure-sensitive adhesive is blended into the pressure-sensitive adhesive layer, the adhesion reliability can be maintained well while the pigment is well dispersed in the layer. In the present embodiment, the content of the carboxy group-containing monomer is preferably 7% by mass or less (typically less than 7% by mass, for example, 6.8% by mass or less, or 6.0% by mass or less) of the monomer component. can

A parent monomer copolymerizable with alkyl (meth)acrylate as a main monomer can be useful for introducing a crosslinking point into an acrylic polymer or increasing the cohesive force of the acrylic polymer. As a parent monomer, for example, the following functional group-containing monomers (however, the above-mentioned carboxy group-containing monomers are not included) can be used individually by 1 type or in combination of 2 or more types.

Hydroxyl group-containing monomers: for example 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate hydroxyalkyl (meth)acrylates such as the like; unsaturated alcohols such as vinyl alcohol and allyl alcohol; Polypropylene glycol mono(meth)acrylate.

Amide group-containing monomers: for example (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N-butyl(meth)acrylamide, N-methylol(meth)acrylamide, N-methylolpropane ( Meth)acrylamide, N-methoxymethyl(meth)acrylamide, N-butoxymethyl(meth)acrylamide.

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

Monomers having an epoxy group: eg glycidyl (meth)acrylate, methylglycidyl (meth)acrylate, allyl glycidyl ether.

Cyano group-containing monomers: eg acrylonitrile, methacrylonitrile.

Keto group-containing monomers: eg diacetone (meth)acrylamide, diacetone (meth)acrylate, vinylmethylketone, vinylethylketone, allylacetoacetate, vinylacetoacetate.

Monomers having nitrogen atom-containing rings: for example N-vinyl-2-pyrrolidone, N-methylvinylpyrrolidone, N-vinylpyridine, N-vinylpiperidone, N-vinylpyrimidine, N-vinylpipette Razine, N-vinylpyrazine, N-vinylpyrrole, N-vinylimidazole, N-vinyloxazole, N-vinylmorpholine, N-vinylcaprolactam, N-(meth)acryloylmorpholine.

Alkoxysilyl group-containing monomers: eg 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropyltriethoxysilane, 3-(meth)acryloxypropylmethyldimethoxysilane, 3- (meth)acryloxypropylmethyldiethoxysilane.

When the monomer component constituting the acrylic polymer contains the functional group-containing monomer as described above, the content of the functional group-containing monomer in the monomer component is not particularly limited. From the viewpoint of appropriately exhibiting the effect of use of the functional group-containing monomer, the content of the functional group-containing monomer in the monomer component can be, for example, 0.1% by mass or more, and is usually suitably 0.5% by mass or more. and may be 1% by mass or more. In addition, from the viewpoint of making it easy to balance the adhesion performance in relation to the main monomer and the carboxyl group-containing monomer, the content of the functional group-containing monomer in the monomer component is usually suitably 40% by mass or less, and 20% by mass It is preferable to set it below, and it is good also as 10 mass % or less (eg 5 mass % or less). The technology disclosed herein can also be preferably carried out in an embodiment in which the monomer component does not substantially contain a functional group-containing monomer (for example, in an embodiment in which the monomer component is substantially composed only of an alkyl (meth)acrylate and a carboxyl group-containing monomer). there is. Here, the fact that the monomer component does not substantially contain a functional group-containing monomer means that the functional group-containing monomer is not used at least intentionally, for example, 0.05% by mass or less (typically 0.01% by mass or less) of the functional group-containing monomer. The unintentional inclusion of is permissible. An acrylic polymer having such a monomer composition may be easily dispersed in a pigment dispersion masterbatch for an adhesive.

The monomer component constituting the acrylic polymer may contain other copolymerization components other than the parent monomer described above for the purpose of improving cohesive force or the like. Examples of other copolymerization components include vinyl ester monomers such as vinyl acetate, vinyl propionate, and vinyl laurate; Aromatic vinyl compounds, such as styrene, substituted styrene ((alpha)-methylstyrene etc.), and vinyltoluene; cycloalkyl (meth)acrylates such as cyclohexyl (meth)acrylate, cyclopentyl (meth)acrylate, and isobornyl (meth)acrylate; Aryl(meth)acrylates (eg phenyl(meth)acrylate), aryloxyalkyl(meth)acrylates (eg phenoxyethyl(meth)acrylate), arylalkyl(meth)acrylates (eg aromatic ring-containing (meth)acrylates such as benzyl (meth)acrylate); olefinic monomers such as ethylene, propylene, isoprene, butadiene, and isobutylene; chlorine-containing monomers such as vinyl chloride and vinylidene chloride; isocyanate group-containing monomers such as 2-(meth)acryloyloxyethyl isocyanate; alkoxy group-containing monomers such as methoxyethyl (meth)acrylate and ethoxyethyl (meth)acrylate; vinyl ether monomers such as methyl vinyl ether and ethyl vinyl ether; Two or more (for example, three or more) polymerizable functional groups (for example, (meth)acryloyl) in one molecule, such as 1,6-hexanedioldi(meth)acrylate and trimethylolpropane tri(meth)acrylate a polyfunctional monomer having a divalent group); and the like.

The amount of these other copolymerization components may be appropriately selected according to the purpose and use, and is not particularly limited. From the viewpoint of appropriately exhibiting the effect of use, it is usually appropriate to be 0.05% by mass or more, and 0.5% by mass or more. can be done with In addition, from the viewpoint of making it easy to balance the adhesive performance, the content of other copolymerization components in the monomer component is usually suitably 20% by mass or less, and 10% by mass or less (for example, 5% by mass or less). can be done with In this embodiment, it can be preferably implemented also in an aspect in which the monomer component does not substantially contain other copolymerization components. Here, the fact that the monomer component does not substantially contain other copolymerization components means that other copolymerization components are not used at least intentionally, and the unintentional inclusion of other copolymerization components, for example, 0.01% by mass or less, is acceptable. can An acrylic polymer having such a monomer composition may be easily dispersed in a pigment dispersion masterbatch for an adhesive.

The method for obtaining the acrylic polymer is not particularly limited, and various polymerization methods known as methods for synthesizing acrylic polymers such as solution polymerization method, emulsion polymerization method, bulk polymerization method, suspension polymerization method, and photopolymerization method can be appropriately employed, and photopolymerization method or solution polymerization method is preferably employable.

The initiator used for polymerization can be appropriately selected from conventionally known thermal polymerization initiators, photopolymerization initiators, and the like, depending on the polymerization method. A polymerization initiator can be used individually by 1 type or in combination of 2 or more types.

For example, when using the photopolymerization method, as the photopolymerization initiator, any suitable photopolymerization initiator can be employed within a range not impairing the effect of the present invention. 1 type of photoinitiator may be sufficient as it, and 2 or more types may be sufficient as it.

Examples of the photopolymerization initiator include, but are not particularly limited to, benzoin ether photopolymerization initiators, acetophenone photopolymerization initiators, α-ketol photopolymerization initiators, aromatic sulfonyl chloride photopolymerization initiators, photoactive oxime photopolymerization initiators, and benzoin photopolymerization initiators. , benzyl-based photopolymerization initiators, benzophenone-based photopolymerization initiators, ketal-based photopolymerization initiators, thioxanthone-based photopolymerization initiators, acylphosphine oxide-based photopolymerization initiators, and the like may be used.

Specific examples of the benzoin ether photopolymerization initiator include benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, and 2,2-dimethoxy-1. , 2-diphenylethan-1-one (as a commercial item, for example, a brand name "Irgacure 651", manufactured by BASF), anisole methyl ether, and the like are exemplified.

Specifically as an acetophenone-type photoinitiator, for example, 1-hydroxycyclohexylphenyl ketone (as a commercial item, for example, a trade name "Irgacure 184", manufactured by BASF), 4-phenoxydichloroacetophenone, 4 -t-butyl-dichloroacetophenone, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one (as a commercial product, for example, a brand name "Irgacure 2959", manufactured by BASF), 2-hydroxy-2-methyl-1-phenyl-propan-1-one (as a commercial item, for example, trade name "Darocure 1173", manufactured by BASF), methoxyaceto Phenone etc. are mentioned.

The amount of the photopolymerization initiator used is not particularly limited, but is, for example, in an amount within the range of 0.01 part by mass to 5 parts by mass, preferably 0.05 part by mass to 3 parts by mass, based on 100 parts by mass of the monomer component used for preparation of the acrylic polymer. can do.

In some embodiments, the acrylic polymer is a partially polymerized product (acrylic polymer syrup) obtained by irradiating ultraviolet rays to a mixture in which a polymerization initiator is blended with a monomer component as described above to polymerize a part of the monomer component, colored It may be included in the colored pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer. The colored pressure-sensitive adhesive composition containing such an acrylic polymer syrup can be applied to a predetermined object to be coated, and the polymerization can be completed by irradiation with ultraviolet rays. That is, the acrylic polymer syrup can be regarded as a precursor of the acrylic polymer. The pressure-sensitive adhesive layer disclosed herein may be formed using, for example, a colored pressure-sensitive adhesive composition containing an acrylic polymer as a base polymer in the form of the acrylic polymer syrup and, if necessary, an appropriate amount of a multifunctional monomer.

As for the preferred polymerization temperature in the case of using the solution polymerization method, the polymerization solvent, and the initiator used for polymerization, the contents described in the section of Resin (A) can be employed.

According to the solution polymerization, a polymerization reaction solution in which an acrylic polymer is dissolved in an organic solvent is obtained. The colored pressure-sensitive adhesive composition forming the pressure-sensitive adhesive layer in the present embodiment may contain an acrylic polymer solution obtained by subjecting the polymerization reaction liquid or the reaction liquid to suitable post-treatment. As the acrylic polymer solution, one prepared by preparing the polymerization reaction solution to an appropriate viscosity (concentration) as necessary can be used. Alternatively, an acrylic polymer solution prepared by synthesizing an acrylic polymer by a polymerization method other than solution polymerization (e.g., emulsion polymerization, photopolymerization, bulk polymerization, etc.) and dissolving the acrylic polymer in an organic solvent may be used.

(other ingredients)

[Dispersion improving component]

The colored pressure-sensitive adhesive composition of the present embodiment may further contain a component contributing to the dispersibility improvement of the pigment dispersion masterbatch for pressure-sensitive adhesive. Such a dispersibility enhancing component may be, for example, a polymer, an oligomer, a liquid resin, or a surfactant. The dispersibility improving component is preferably dissolved in the base polymer composition. The oligomer is, for example, a low molecular weight polymer of a monomer component containing one or two or more of the acrylic monomers as exemplified above (for example, Mw is less than 10 × 10 ⁴ , preferably 5 × 10 less than ⁴ acrylic oligomers). The liquid resin is, for example, a tackifying resin having a softening point of 50 ° C. or less, more preferably 40 ° C. or less (typically rosin-based, terpene-based, hydrocarbon-based tackifying resins, for example, hydrogenated rosin methyl esters, etc.). By such a dispersibility improving component, the dispersion nonuniformity of a pigment can be suppressed, and also the color nonuniformity of the adhesive layer formed with the colored adhesive composition can be suppressed. Therefore, it is possible to form a pressure-sensitive adhesive layer with better appearance quality.

The content of the dispersibility improving component is not particularly limited, and is usually 20% by mass or less (preferably 10% by mass) of the entire colored pressure-sensitive adhesive composition (pressure-sensitive adhesive layer) from the viewpoint of suppressing the influence on the adhesive properties (eg, decrease in cohesiveness). It is suitable to set it as mass % or less, More preferably, 7 mass % or less, for example, 5 mass % or less). In one aspect, the content of the dispersibility improving component can be 10 times or less (preferably 5 times or less, for example, 3 times or less) of the mass of the pigment dispersion masterbatch for pressure-sensitive adhesive. On the other hand, from the viewpoint of suitably exhibiting the effect of the dispersibility improving component, its content is usually 0.2% by mass or more (typically 0.5% by mass or more, preferably 1% by mass or more) of the entire colored pressure-sensitive adhesive composition. it is suitable In one aspect, the content of the dispersibility improving component can be 0.2 times or more (preferably 0.5 times or more, for example 1 time or more) the mass of the pigment dispersion masterbatch for pressure-sensitive adhesive.

[tackifying resin]

Tackifying resin can be contained in the colored adhesive composition of this embodiment. Thereby, the adhesion reliability of the adhesive layer and the adhesive sheet formed with the said colored adhesive composition can be improved. As the tackifying resin, phenol-based tackifying resin, terpene-based tackifying resin, modified terpene-based tackifying resin, rosin-based tackifying resin, hydrocarbon-based tackifying resin, epoxy-based tackifying resin, polyamide-based tackifying resin, elastomer One type or two or more types selected from various known tackifying resins such as type tackifying resins and ketone type tackifying resins can be used.

Examples of phenolic tackifying resins include terpene phenol resins, hydrogenated terpene phenol resins, alkyl phenol resins, and rosin phenol resins.

Terpene phenol resin refers to a polymer containing a terpene residue and a phenol residue, and includes a copolymer of terpenes and phenol compounds (terpene-phenol copolymer resin) and a phenol-modified terpene homopolymer or copolymer ( It is a concept including both phenol-modified terpene resin) and. Suitable examples of the terpenes constituting the terpene phenol resin include monoterpenes such as α-pinene, β-pinene, and limonene (including d-, l-, and d/l-forms (dipentene)). . A hydrogenated terpene phenol resin refers to a hydrogenated terpene phenol resin having a structure obtained by hydrogenating such a terpene phenol resin. It is sometimes called hydrogenated terpene phenol resin.

Alkyl phenol resin is a resin (oil-based phenol resin) obtained from an alkyl phenol and formaldehyde. Examples of the alkylphenol resin include novolak type and resol type resins.

The rosin phenol resin is typically a phenol-modified product of rosin or various rosin derivatives described above (including rosin esters, unsaturated fatty acid-modified rosin, and unsaturated fatty acid-modified rosin esters). Examples of the rosin phenol resin include rosin phenol resins obtained by a method of thermal polymerization by adding phenol to rosin or various rosin derivatives described above using an acid catalyst.

Examples of the terpene-based tackifying resin include polymers of terpenes (typically monoterpenes) such as α-pinene, β-pinene, d-limonene, l-limonene, and dipentene. It may be a homopolymer of one type of terpenes or a copolymer of two or more types of terpenes. Examples of homopolymers of one type of terpenes include α-pinene polymers, β-pinene polymers, and dipentene polymers. As an example of a modified terpene resin, what modified|denatured the said terpene resin is mentioned. Specifically, styrene-modified terpene resins and hydrogenated terpene resins are exemplified.

The concept of the rosin-based tackifying resin as used herein includes both rosin and rosin derivative resin. Examples of rosins include unmodified rosins such as gum rosin, wood rosin, and tall oil rosin (raw rosin); Modified rosin (hydrogenated rosin, disproportionated rosin, polymerized rosin, other chemically modified rosin, etc.) obtained by modifying these unmodified rosins by hydrogenation, disproportionation, polymerization, etc. is included.

The rosin derivative resin is typically a derivative of the above rosins. The concept of the rosin-based resin herein includes derivatives of unmodified rosin and derivatives of modified rosin (including hydrogenated rosin, disproportionated rosin, and polymerized rosin). For example, rosin esters such as unmodified rosin esters that are esters of unmodified rosin and alcohols and modified rosin esters that are esters of modified rosin and alcohols; For example, rosins modified with unsaturated fatty acids obtained by modifying rosins with unsaturated fatty acids; For example, unsaturated fatty acid modified rosin esters obtained by modifying rosin esters with unsaturated fatty acids; For example, rosin alcohols obtained by reducing the carboxy group of rosin or various rosin derivatives described above (including rosin esters, unsaturated fatty acid-modified rosin, and unsaturated fatty acid-modified rosin esters); For example, metal salts of rosin or various rosin derivatives described above. Specific examples of rosin esters include methyl esters of unmodified rosin or modified rosin (hydrogenated rosin, disproportionated rosin, polymerized rosin, etc.), triethylene glycol esters, glycerin esters, and pentaerythritol esters.

Examples of hydrocarbon-based tackifying resins include aliphatic hydrocarbon resins, aromatic hydrocarbon resins, aliphatic cyclic hydrocarbon resins, aliphatic/aromatic petroleum resins (styrene-olefin copolymers, etc.), aliphatic/alicyclic petroleum resins, and hydrogenated hydrocarbons. Resin, various hydrocarbon-type resins, such as a coumarone-type resin and a coumarone-indene-type resin, are mentioned.

The softening point of the tackifying resin is not particularly limited. From the viewpoint of improving cohesive force, in one aspect, a tackifying resin having a softening point (softening temperature) of 80°C or higher (preferably 100°C or higher) can be preferably employed. In the technique disclosed herein, the total amount of the tackifying resin contained in the pressure-sensitive adhesive layer is 100% by mass, of which more than 50% by mass (more preferably more than 70% by mass, for example more than 90% by mass) is the above. It can be preferably carried out in an aspect of a tackifying resin having a softening point. For example, phenolic tackifying resins (such as terpene phenol resins) having such a softening point can be preferably used. The tackifying resin may contain, for example, a terpene phenol resin having a softening point of 135°C or higher (moreover, 140°C or higher). The upper limit of the softening point of the tackifying resin is not particularly limited. From the viewpoint of improving adhesion to adherends, in one aspect, a tackifying resin having a softening point of 200°C or less (more preferably 180°C or less) can be preferably used. In a preferred aspect, the softening point of the tackifying resin (typically a terpene phenol resin) is less than 130°C, for example 120°C or less. Thus, by using a tackifying resin having a relatively low softening point, for example, the dispersibility of a pigment can be improved. In addition, the softening point of the tackifying resin can be measured based on the softening point test method (ring and ball method) specified in JIS K2207.

As one preferable aspect, the aspect in which the said tackifying resin contains 1 type, or 2 or more types of phenol type tackifying resin (typically a terpene phenol resin) is mentioned. The technique disclosed herein may be preferably carried out in an aspect in which, for example, the total amount of the tackifying resin is 100% by mass, of which 25% by mass or more (more preferably 30% by mass or more) is a terpene phenol resin. . 50 mass % or more of the total amount of tackifying resin may be a terpene phenol resin, and 80 mass % or more (for example, 90 mass % or more) may be a terpene phenol resin. Substantially all of the tackifying resin (for example, 95 to 100% by mass, further 99 to 100% by mass) may be a terpene phenol resin.

When the colored pressure-sensitive adhesive composition forming the pressure-sensitive adhesive layer contains a tackifying resin, the amount of the tackifying resin used is not particularly limited, and is appropriately set in the range of 1 to 100 parts by mass, for example, based on 100 parts by mass of the base polymer. can From the viewpoint of suitably exhibiting the effect of improving the peel strength, the amount of colored tackifying resin used per 100 parts by mass of the base polymer (eg acrylic polymer) is usually suitably 5 parts by mass or more, and 10 parts by mass It is preferable to set it as part or more, and it is good also considering it as 15 mass parts or more. For example, in the pressure-sensitive adhesive layer containing a pigment, the dispersibility of the pigment tends to be improved by including a predetermined amount of a tackifying resin (for example, a terpene phenol resin having a softening point of 120°C or less). In addition, from the viewpoint of heat-resistant cohesion, the amount of colored tackifying resin used per 100 parts by mass of the base polymer (eg acrylic polymer) is usually suitably 50 parts by mass or less, and may be 40 parts by mass or less, It is good also as 30 mass parts or less.

[Crosslinking agent]

The colored pressure-sensitive adhesive composition forming the pressure-sensitive adhesive layer of the present embodiment may also contain a crosslinking agent as needed. The type of crosslinking agent is not particularly limited, and can be appropriately selected and used from conventionally known crosslinking agents. Examples of such crosslinking agents include isocyanate crosslinking agents, epoxy crosslinking agents, oxazoline crosslinking agents, aziridine crosslinking agents, melamine crosslinking agents, peroxide crosslinking agents, urea crosslinking agents, metal alkoxide crosslinking agents, metal chelate crosslinking agents, metal salt crosslinking agents, A carbodiimide-type crosslinking agent, a hydrazine-type crosslinking agent, an amine-type crosslinking agent, a silane coupling agent, etc. are mentioned. A crosslinking agent can be used individually by 1 type or in combination of 2 or more types.

The total amount of the crosslinking agent used is not particularly limited. For example, it can be 10 parts by mass or less, preferably 0.005 to 10 parts by mass, more preferably 0.01 to 5 parts by mass, based on 100 parts by mass of the base polymer (preferably acrylic polymer). .

In addition, the colored pressure-sensitive adhesive composition forming the pressure-sensitive adhesive layer, if necessary, a leveling agent, a crosslinking aid, a plasticizer, a softener, an antistatic agent, an antiaging agent, an ultraviolet absorber, an antioxidant, a light stabilizer, and the like, common in the field of pressure-sensitive adhesive. It may contain various additives. Regarding these various additives, conventionally known ones can be used by conventional methods, and since they do not particularly characterize the present invention, detailed descriptions are omitted.

The pressure-sensitive adhesive layer of the present embodiment is not particularly limited as long as it is formed of the colored pressure-sensitive adhesive composition of the present embodiment, and may be a pressure-sensitive adhesive layer formed of a water-based pressure-sensitive adhesive composition, a solvent-type pressure-sensitive adhesive composition, a hot-melt pressure-sensitive adhesive composition, or an active energy ray-curable pressure-sensitive adhesive composition. there is. The water-based pressure-sensitive adhesive composition refers to a pressure-sensitive adhesive composition containing an pressure-sensitive adhesive (a pressure-sensitive adhesive layer forming component) in a solvent containing water as a main component (aqueous solvent), and typically, a water-dispersible pressure-sensitive adhesive composition (at least a part of the pressure-sensitive adhesive is dispersed in water). Composition in the form) and the like are included. In addition, a solvent type adhesive composition refers to the adhesive composition of the form containing an adhesive in an organic solvent. This embodiment can be preferably implemented in the aspect provided with the adhesive layer formed from the solvent type adhesive composition from viewpoints, such as adhesive characteristics.

In the case where the pressure-sensitive adhesive layer has a multilayer structure of two or more layers, it can be produced by bonding previously formed pressure-sensitive adhesive layers. Alternatively, a pressure-sensitive adhesive composition may be applied on a previously formed first pressure-sensitive adhesive layer, and the pressure-sensitive adhesive composition is cured to form a second pressure-sensitive adhesive layer, and at least one pressure-sensitive adhesive composition may be a colored pressure-sensitive adhesive composition according to an embodiment of the present invention. When the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet described below, which is used in the form of photo-curing after bonding to an adherend, has a multilayer structure, the photo-curing pressure-sensitive adhesive layer is a part of the layer included in the multilayer structure (for example, one layer ) or all layers.

When the colored pressure-sensitive adhesive composition is applied to form the pressure-sensitive adhesive layer, for example, a gravure roll coater, a reverse roll coater, a kiss roll coater, a dip roll coater, a bar coater, a knife coater, a spray coater, etc. can do. In the PSA sheet having a base material, as a method for forming the pressure-sensitive adhesive layer on the base material, a direct method in which a colored 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 is used as the base material. You may also use a transcription method that transfers to

The thickness of the pressure-sensitive adhesive layer is not particularly limited, and may be, for example, 3 μm to 2000 μm. From the standpoint of adhesion to adherends such as step followability, in some embodiments, the thickness of the pressure-sensitive adhesive layer may be, for example, 5 μm or more, preferably 10 μm or more, preferably 20 μm or more, and more preferably 30 μm. More than that. 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. Further, from the viewpoint of preventing the generation of adhesive residue due to cohesive failure of the pressure-sensitive adhesive layer, in some embodiments, 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 300 μm or less, 200 μm or less, or 170 μm or less. The technique related to this embodiment can be suitably implemented also in the form of a pressure-sensitive adhesive sheet described later in which the thickness of the pressure-sensitive adhesive layer is 130 μm or less, 90 μm or less, or 60 μm or less (for example, 40 μm or less). In addition, in the pressure-sensitive adhesive sheet described later having a pressure-sensitive adhesive layer having a multilayer structure of two or more layers, the thickness of the pressure-sensitive adhesive layer refers to the thickness from the adhesive surface to be adhered to the adherend to the surface opposite to the adhesive surface.

<Adhesive Sheet>

The pressure-sensitive adhesive sheet according to the embodiment of the present invention includes a pressure-sensitive adhesive layer (colored pressure-sensitive adhesive) formed of the colored pressure-sensitive adhesive composition. That is, the pressure-sensitive adhesive sheet according to the embodiment of the present invention includes a pressure-sensitive adhesive layer made of the colored pressure-sensitive adhesive composition. The pressure-sensitive adhesive sheet of the present embodiment may be a pressure-sensitive adhesive sheet having a base material having a pressure-sensitive adhesive layer on one side (Fig. 2) or both sides (Fig. 3) of a sheet-like base material (support), and the pressure-sensitive adhesive layer is held by a release liner. It may be a pressure-sensitive adhesive sheet made of an inorganic material or the like. The concept of the pressure-sensitive adhesive sheet herein may include what is called an adhesive tape, an adhesive label, an adhesive film, and the like.

Further, the pressure-sensitive adhesive layer is typically formed continuously, but is not limited to this form, and may be, for example, a pressure-sensitive adhesive layer formed in a regular or random pattern such as dots or stripes. In addition, the PSA sheet of the present embodiment may be in the form of a roll or sheet. Alternatively, it may be a pressure-sensitive adhesive sheet processed into various shapes.

From the viewpoint of having conformability to steps, the pressure-sensitive adhesive sheet of the present embodiment may be of an inorganic material (pressure-sensitive adhesive layer) without a base material as shown in FIG. 1 . When there is a step (for example, 10 μm) on the object to which the PSA sheet is attached, the PSA sheet has step followability, so that the PSA sheet can be pasted along the step. Thereby, the adhesive sheet can be affixed to the object without gaps.

Moreover, the adhesive sheet of this embodiment may contain the support base material as shown in FIG. In this way, the pressure-sensitive adhesive sheet can be processed with high precision by punching or the like. Such an adhesive sheet is suitable for applications in which it is processed into a specific shape or narrowed in width. In addition, the thickness of the support base material in this embodiment is less than 75 micrometers, for example. A support substrate having a limited thickness is preferably used for applications requiring thinning or weight reduction. Further, for example, by limiting the thickness of the supporting base material and increasing the thickness of the pressure-sensitive adhesive layer relatively, adhesion characteristics such as adhesion reliability can be improved. From that point of view, the thickness of the supporting substrate is preferably 60 μm or less, more preferably 50 μm or less (for example, less than 50 μm), still more preferably 40 μm or less, particularly preferably 30 μm or less (for example, less than 30 μm, typically 25 μm or less). In one aspect, the thickness of the supporting substrate may be 20 μm or less, 12 μm or less, or 7 μm or less (for example, 3 μm or less). The lower limit of the thickness of the supporting substrate is not particularly limited. From the standpoint of the handleability (handling property) and workability of the PSA sheet, the thickness of the supporting base material is usually 0.5 μm or more (for example, 1 μm or more). In one aspect, the thickness of the supporting substrate may be 3 μm or more. In another aspect, the thickness of the supporting substrate may be 8 μm or more, may be 13 μm or more, or may be 16 μm or more.

The structure and material of the supporting substrate are not particularly limited, and are typically film-like substrates (also referred to as "substrate films"). As a base film, what contains a resin film as a base film can be used suitably. The base film is typically a (independent) member capable of independently maintaining its shape. The base film in this embodiment may be substantially constituted by such a base film. Alternatively, the base film may include an auxiliary layer in addition to the base film. Examples of the auxiliary layer include a colored layer, a reflective layer, an undercoat layer, and an antistatic layer provided on the surface of the base film.

The said resin film is a film which has a resin material as a main component (for example, the component contained in the said resin film exceeding 50 mass %). Examples of resin films include polyolefin resin films such as polyethylene (PE), polypropylene (PP), and ethylene/propylene copolymers; polyester resin films such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polyethylene naphthalate (PEN); Polyurethane-based resin film; Vinyl chloride-based resin film; vinyl acetate-based resin film; polyimide-based resin film; polyamide-based resin film; fluororesin film; Cellophane etc. are mentioned. The resin film may be a rubber-based film such as a natural rubber film or a butyl rubber film. Among them, from the viewpoints of handleability and workability, a polyester film is preferred, and among these, a PET film is particularly preferred. In addition, in this specification, a "resin film" is typically a non-porous sheet, and is a concept distinguished from so-called nonwoven fabrics and woven fabrics (in other words, a concept excluding nonwoven fabrics and woven fabrics).

Various additives such as fillers (inorganic fillers, organic fillers, etc.), dispersants (surfactants, etc.), anti-aging agents, antioxidants, ultraviolet absorbers, antistatic agents, lubricants, and plasticizers may be blended with the base film as necessary. . The blending ratio of various additives is usually less than 30% by mass (for example, less than 20% by mass, typically less than 10% by mass).

Conventionally well-known surface treatment, such as corona discharge treatment, plasma treatment, ultraviolet irradiation treatment, acid treatment, alkali treatment, and coating of a primer, may be given to the surface of a base film. Such surface treatment may be a treatment for improving the adhesion between the base film and the pressure-sensitive adhesive layer, in other words, the anchoring property of the pressure-sensitive adhesive layer to the base film. In addition, when the technique disclosed herein is implemented in the form of a single-sided adhesive sheet provided with a base material, the back surface of the base film may be subjected to peeling treatment as needed. The release treatment may be, for example, a treatment in which a release treatment agent, such as a general silicone-based, long-chain alkyl-based, or fluorine-based release agent, is typically applied in a thin film form of 0.01 µm to 1 µm (eg 0.01 µm to 0.1 µm). By performing such a peeling treatment, an effect such as facilitating rewinding of a wound object obtained by winding an adhesive sheet in a roll shape is obtained.

In addition, in the PSA sheet of the present embodiment, a release liner can be used for forming the PSA layer, preparing the PSA sheet, preserving the PSA sheet before use, distributing, shaping, and the like. The release liner is not particularly limited, and examples thereof include a release liner having a release treatment layer on the surface of a liner substrate such as a resin film or paper, a fluorine-based polymer (polytetrafluoroethylene, etc.) or a polyolefin-based resin (polyethylene, A release liner made of a low adhesive material such as polypropylene or the like can be used. The release treatment layer may be formed by surface treatment of the liner substrate with a release treatment agent such as silicon, long-chain alkyl, fluorine, or molybdenum sulfide.

(Thickness of adhesive sheet)

The total thickness of the pressure-sensitive adhesive sheet of the present embodiment (including a pressure-sensitive adhesive layer and further including a support substrate in the configuration having a support substrate, but not including a release liner) is not particularly limited. The total thickness of the pressure-sensitive adhesive sheet is usually preferably 200 μm or less from the viewpoint of thinning. The lower limit of the thickness of the pressure-sensitive adhesive sheet is not particularly limited, and can usually be 1 μm or more, for example, 3 μm or more is appropriate, preferably 6 μm or more, more preferably 10 μm or more (for example, 15 μm or more). above) is

In one preferred aspect, the total thickness of the pressure-sensitive adhesive sheet is 150 μm or less, more preferably 120 μm or less, even more preferably 70 μm or less, particularly preferably 50 μm or less (eg 40 μm or less), for example 35 μm or less. It may be 25 μm or less, and may be 15 μm or less or 10 μm or less (for example, 7 μm or less). Even in a configuration using such a thin pressure-sensitive adhesive sheet, the light-blocking effect according to the present embodiment can be exhibited favorably.

The ratio of the total thickness of the PSA layer included in the PSA sheet to the total thickness of the PSA sheet is not particularly limited. Here, the total thickness of the pressure-sensitive adhesive layer included in the pressure-sensitive adhesive sheet refers to the total thickness of the pressure-sensitive adhesive layer provided on one surface of the base film and the pressure-sensitive adhesive layer provided on the other surface. In the case of a single-sided PSA sheet in which an adhesive layer is provided only on one surface of a base film, the thickness of the PSA layer provided on the other surface is zero, and the thickness of the PSA layer provided on the one surface and the sum of the PSA layer Thickness matches. In the technology disclosed herein, for example, the ratio of the total thickness of the pressure-sensitive adhesive layer to the total thickness of the pressure-sensitive adhesive sheet is 40% or more (preferably 50% or more, typically more than 50%, more preferably 60% or more) , more preferably 70% or more). In one aspect, the ratio of the total thickness of the pressure-sensitive adhesive layer to the total thickness of the pressure-sensitive adhesive sheet may be 75% or more, or even 80% or more. The upper limit of the ratio of the total thickness of the pressure-sensitive adhesive layer to the total thickness of the pressure-sensitive adhesive sheet is not particularly limited, but is usually suitably 95% or less, and preferably 90% or less.

Examples of the use of the pressure-sensitive adhesive layer and pressure-sensitive adhesive sheet of the present embodiment include housings for electronic devices, structural parts for vehicles, housings for vehicles, housings for home appliances, structural parts, mechanical parts, various automobile parts, and electronic device parts. , household items such as furniture and kitchen utensils, medical devices, building material parts, other structural parts and exterior parts, and the like.

More specifically, as electronic devices and home appliances, refrigerators, washing machines, vacuum cleaners, microwave ovens, air conditioners, lighting equipment, electric water heaters, televisions, clocks, ventilation fans, projectors, home appliances such as speakers, personal computers, mobile phones, and smartphones , digital cameras, tablet PCs, portable music players, portable game consoles, chargers, and electronic information devices such as batteries.

In relation to vehicles, instrument panel, console box, door knob, door trim, shift lever, pedals, glove box, bumper, bonnet, fender, trunk, door, roof, pillar, seat seat, steering wheel, ECU box, electric parts , engine peripheral parts, driving system/gear peripheral parts, intake/exhaust system parts, cooling system parts, etc.

Example

Hereinafter, the present invention will be described in more detail by way of Examples and Comparative Examples, but the present invention is not intended to be limited to those shown in these Examples. In the following description, "part" and "%" are based on mass unless otherwise specified.

<Evaluation method>

[Measurement of Median Diameter of Dispersed Particles of Pigment]

As a median diameter measurement method, measurement was performed using ethyl acetate as a dispersion medium using a laser diffraction/scattering type particle size distribution analyzer LA-950 (manufactured by Horiba Seisakusho). The relative refractive index was calculated and measured from the respective refractive indices of ethyl acetate and the pigment to be used, thereby measuring the dispersed particles of the pigment in the dispersion. From the measurement result, the median diameter of the dispersed particles of the pigment in the dispersion is obtained.

[Standard Deviation of Transmittance]

The polyester film A of the adhesive sheets of Examples and Comparative Examples was peeled off and bonded to slide glass (trade name "S1112", manufactured by Matsunami Glass Co., Ltd.) with a hand roller. The light transmittance of the obtained glass sample at a wavelength of 300 nm to 800 nm was measured with a spectrophotometer ("UH4150", manufactured by Hitachi High-Tech Science Co., Ltd.) for ultraviolet, visible, and near-infrared. From the obtained transmittance spectrum, the transmittance at the wavelength at which the transmittance becomes the lowest at 400 to 800 nm was obtained.

Ten points were measured for each sample, and a standard deviation (σ) was calculated for the transmittance at 560 nm of the ten points, and the in-plane color unevenness of the pressure-sensitive adhesive layer was evaluated. The case where the standard deviation (σ) was less than 1.2 was evaluated as ○, and the case of 1.2 or more was evaluated as ×.

[Reliability of adhesion]

In the adhesive sheets of Examples and Comparative Examples, adhesive strength was evaluated by performing a peel adhesive force test in accordance with JIS Z 0237:2009.

That is, in an environment of a temperature of 23°C and a relative humidity of 50% RH, a PET film having a thickness of 25 μm was attached to one side of the adhesive side of the pressure-sensitive adhesive double-sided sheet for backing, and cut into a width of 20 mm to prepare a measurement sample. The other adhesive surface of the measurement sample was attached to a glass plate as an adherend with an adhesive area of 20 mm in width and 100 mm in length by reciprocating a 2 kg roller once. In this way, the measurement sample affixed to the adherend was left to stand for 30 minutes. Thereafter, the force (N/20 mm) at the time of peeling the measurement sample from the adherend at a peel angle of 180° and a measurement speed of 300 mm/min was measured.

The measurement sample prepared separately was left to stand for 500 hours in an environment of a temperature of 85°C and a relative humidity of 85%. Then, adhesive force was measured by the same method.

The rate of change in adhesive force before and after leaving in an environment of 85°C and 85% relative humidity was calculated with the following formula, and when the rate of change was 100 (%) or more, it was marked as ○, and when it was less than 100 (%) as ×, it was evaluated for adhesion reliability. .

Change rate (%) = (adhesive force after standing - adhesive force before standing) ÷ (adhesive force before standing) × 100

<Preparation of (meth)acrylic polymer>

100 parts by mass of toluene, 60 parts by mass of dicyclopentanyl methacrylate (DCPMA) (trade name: FA-513M, manufactured by Hitachi Chemical Industry Co., Ltd.), 40 parts by mass of methyl methacrylate (MMA), and α-thio as a chain transfer agent 3.5 parts by mass of glycerol (TGR) was introduced into a four-necked flask. Then, after stirring at 70°C in a nitrogen atmosphere for 1 hour, 0.2 parts by mass of azobisisobutyronitrile was added as a thermal polymerization initiator, followed by reaction at 70°C for 2 hours, followed by reaction at 80°C for 2 hours. Thereafter, the reaction solution was introduced under a temperature atmosphere of 130°C, and toluene, chain transfer agent, and unreacted monomers were removed by drying to obtain a solid (meth)acrylic polymer. The obtained (meth)acrylic polymer had a glass transition temperature of 144°C and a weight average molecular weight of 4300.

<Preparation of photopolymerizable composition (adhesive composition)>

2-ethylhexyl acrylate (78 parts by mass), N-vinyl-2-pyrrolidone (18 parts by mass) and hydroxyethyl acrylate (4 parts by mass) as monomer components, and 2,2-dimethine as a photopolymerization initiator Toxy-1,2-diphenyl-1-one (trade name "Irgacure 651", manufactured by Ciba Japan) (0.035 parts by mass) and 1-hydroxy-cyclohexyl-phenyl-ketone (trade name "Irgacure 184") , Ciba Japan Co., Ltd.) (0.035 parts by mass) was put into a four-necked flask equipped with a stirrer, thermometer, nitrogen gas inlet tube, reflux condenser and dropping funnel, and partially photopolymerized by exposing to ultraviolet rays in a nitrogen atmosphere, thereby partially polymerizing the product. (monomer syrup) was obtained.

To this partial polymer (100 parts by mass), 1,6-hexanedioldiacrylate (0.088 parts by mass), the above (meth)acrylic polymer (11.8 parts by mass) and γ-glycidoxypropyltrimethoxysilane (KBM- 403, manufactured by Shin-Etsu Silicone Co., Ltd., 0.35 parts by mass) was added, and then mixed uniformly to prepare a photopolymerizable composition (adhesive composition).

<Preparation of pressure-sensitive adhesive composition 1>

In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas inlet pipe, 60 parts by mass of n-butyl acrylate, 18 parts by mass of 4-hydroxybutyl acrylate, and 22 parts by mass of n-vinylpyrrolidone And, a mixture containing 0.2 parts by mass of 2,2'-azobisisobutyronitrile (AIBN) as a polymerization initiator and 122 parts by mass of ethyl acetate as a solvent was stirred at 60°C for 7 hours under a nitrogen atmosphere (polymerization reaction ). In this way, a polymer solution containing an acrylic polymer was obtained. The acrylic polymer weight average molecular weight (Mw) in this polymer solution was 400,000.

<Preparation of pressure-sensitive adhesive composition 2>

In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas inlet tube, 96 parts by mass of 2-ethylhexyl acrylate, 4 parts by mass of 2-hydroxyethyl acrylate, and 2,2'- as a polymerization initiator A mixture containing 0.2 parts by mass of azobisisobutyronitrile (AIBN) and 122 parts by mass of ethyl acetate as a solvent was stirred at 60°C for 7 hours in a nitrogen atmosphere (polymerization reaction). In this way, a polymer solution containing an acrylic polymer was obtained. The weight average molecular weight (Mw) of the acrylic polymer in this polymer solution was 600,000.

<Preparation of Masterbatch Resin 1>

After introducing 47 parts by mass of toluene into an autoclave and substituting with nitrogen, the temperature was raised to 140°C in a hermetically sealed state under stirring. 20 parts by mass of methyl acrylate, 68 parts by mass of 2-ethylhexyl acrylate, 10 parts by mass of N-vinyl-2-pyrrolidone, 2 parts by mass of acrylic acid (all manufactured by Tokyo Kasei Kogyo Co., Ltd.), perbutyl O (Nippon Yushi Co., Ltd.) Co., Ltd.) 1 part by mass and 80 parts by mass of xylene were polymerized over 3 hours while controlling the temperature in the autoclave to 105°C. Thereafter, reaction was performed at 175°C for 1 hour. After that, desolvation was performed at 170°C to obtain Masterbatch Resin 1.

<Preparation of Masterbatch Resin 2>

Masterbatch resin 2 was obtained in the same manner as in masterbatch resin 1 except that the composition of the monomer was changed as shown in Table 1.

<Preparation of Masterbatch Resin 3>

Masterbatch resin 3 was obtained in the same manner as in masterbatch resin 1 except that the composition of the monomer was changed as shown in Table 1.

<Preparation of Masterbatch Resin 4>

After introducing 47 parts by mass of toluene into an autoclave and substituting with nitrogen, the temperature was raised to 140°C in a hermetically sealed state under stirring. 15 parts by mass of methyl acrylate, 71 parts by mass of 2-ethylhexyl acrylate, 12 parts by mass of N-vinyl-2-pyrrolidone, 2 parts by mass of acrylic acid (all manufactured by Tokyo Kasei Kogyo Co., Ltd.), perbutyl O (Nippon Yushi Co., Ltd.) Co., Ltd.) 1 part by mass and 80 parts by mass of xylene were polymerized over 3 hours while controlling the temperature in the autoclave to 105°C. Thereafter, reaction was performed at 175°C for 1 hour. Thereafter, desolvation was performed at 170°C to obtain Masterbatch Resin 4.

<Preparation of Masterbatch Resin 5>

After introducing 47 parts by mass of toluene into an autoclave and substituting with nitrogen, the temperature was raised to 140°C in a hermetically sealed state under stirring. 30 parts by mass of methyl acrylate, 68 parts by mass of 2-ethylhexyl acrylate, 2 parts by mass of acrylic acid (all manufactured by Tokyo Kasei Kogyo Co., Ltd.), 1 part by mass of Perbutyl O (manufactured by Nippon Yushi Co., Ltd.), and 90 parts by mass of xylene The mixed solution was polymerized over 3 hours while controlling the temperature in the autoclave to 105°C. Thereafter, reaction was performed at 175°C for 1 hour. Thereafter, desolvation was performed at 170°C to obtain Masterbatch Resin 5.

The monomer composition, Tg and acid value of masterbatch resins 1 to 5 were as shown in Table 1. Table 1 also shows the weight average molecular weight (Mw) and number average molecular weight (Mn) of the masterbatch resins 1 to 5.

<Production Example 1 Production of Pigment Dispersion 1>

As the resin for the pigment dispersion masterbatch for the adhesive, 175 parts by mass of the masterbatch resin prepared above and 25 parts by mass of the magenta pigment (Pigment Red 122) were kneaded with Plastomill (manufactured by Toyo Seiki Seisakusho Co., Ltd.), 72 parts by mass of the obtained pigment dispersion resin was previously mixed and dissolved with 28 parts by mass of 2-ethylhexyl acrylate, put into a vessel for a sand grinder, and 120 g of 0.4 mmφ glass beads were added and dispersed. The dispersed particle size of the pigment was measured with a laser diffraction/scattering type particle size distribution analyzer LA-950, and at the point of no change, dispersion was terminated, and the glass beads were removed to obtain Pigment Dispersion 1. The median diameter of the dispersed particles of the pigment in the pigment dispersion liquid 1 was 100 nm.

<Production Example 2 Production of Pigment Dispersion 2>

28 parts by mass of 2-ethylhexyl acrylate, 54 parts by mass of the masterbatch resin 1 prepared above as a resin for the pigment dispersion masterbatch for the adhesive, and 18 parts by mass of the magenta pigment (pigment red 122) were previously mixed and dissolved, It was put into a vessel for a grinder, and 120 g of 0.4 mmφ glass beads were added to perform dispersion. The dispersed particle size of the pigment was measured with a laser diffraction/scattering type particle size distribution analyzer LA-950, and at the point of no change, dispersion was terminated, and the glass beads were removed to obtain Pigment Dispersion 2. The median diameter of the dispersed particles of the pigment in the pigment dispersion liquid 2 was 800 nm.

<Production Example 3 Production of Pigment Dispersion 3>

When 54 parts by mass of pigment dispersant 1 (trade name "Floren DOPA 15BHFS" manufactured by Kyoeisha) was mixed in advance with 18 parts by mass of magenta pigment (Pigment Red 122) to form a uniform paste, 28 parts by mass of 2-ethylhexyl acrylate After addition, it was put into a vessel for a sand grinder, and 120 g of 0.4 mmφ glass beads were added to perform dispersion. The dispersed particle size of the pigment was measured with a laser diffraction/scattering type particle size distribution analyzer LA-950, and at the point of no change, dispersion was terminated, and the glass beads were removed to obtain Pigment Dispersion 3. The median diameter of the dispersed particles of the pigment in the pigment dispersion liquid 3 was 100 nm.

<Production Example 4 Production of Pigment Dispersion 4>

A pigment dispersion 4 was obtained in the same manner as in Production Example 3 except that the pigment dispersant 1 was replaced with the dispersant 2 (trade name "DISPER BYK-145" manufactured by Big Chemie Japan BYK). The median diameter of the dispersed particles of the pigment in the pigment dispersion 4 was 100 nm.

<Production Example 5 Production of Pigment Dispersion 5>

Pigment dispersion 5 was obtained in the same manner as in Production Example 3 except that the magenta pigment (Pigment Red 122) was replaced with the black pigment (Pigment Black 7) and 2-ethylhexyl acrylate was replaced with ethyl acetate. The median diameter of the dispersed particles of the pigment in the pigment dispersion 5 was 100 nm.

<Examples and Comparative Examples>

(Preparation of micro masterbatch 1 (MMB1))

Masterbatch resin 1 (75 parts by mass) and magenta pigment (Pigment Red 122) (25 parts by mass) were introduced into the mixer unit using Labo Plastomill (Roller Mixer R60) manufactured by Toyo Seiki, and heated to 100°C, Kneading was performed at 150 rpm. The sampled pigment dispersion was dissolved and dispersed in ethyl acetate, and the dispersed particle size of the pigment was measured with a laser diffraction/scattering type particle size distribution analyzer LA-950, and the dispersion was terminated at the point of no change. A micro masterbatch (MMB1) was obtained.

(Preparation of micro masterbatch 2 (MMB2))

A micro masterbatch for adhesives (MMB2) of a comparative example was obtained in the same manner as in the preparation of micro masterbatch 1 (MMB1) except that masterbatch resin 1 was replaced with masterbatch resin 2.

(Preparation of micro masterbatch 3 (MMB3))

Micro masterbatch 3 (MMB3) for adhesives of a comparative example was obtained in the same manner as in the preparation of micro masterbatch 1 (MMB1) except that masterbatch resin 1 was replaced with masterbatch resin 3.

(Preparation of micro masterbatch 4 (MMB4))

Except for replacing the magenta pigment (Pigment Red 122) with the blue pigment (Pigment Blue 15:3), the micro master batch 1 (MMB1) was prepared in the same manner as the micro master batch 4 (MMB4) for adhesives.

(Preparation of micro masterbatch 5 (MMB5))

Except for replacing the magenta pigment (Pigment Red 122) with a yellow pigment (Pigment Yellow 185), the micro master batch 1 (MMB1) was prepared in the same manner as the micro master batch 5 (MMB5) for adhesives.

(Preparation of micro masterbatch 6 (MMB6))

Except for changing the magenta pigment (Pigment Red 122) to the black pigment (Pigment Black 7) and changing the master batch resin 1 to the master batch resin 4, the preparation of the micro master batch 1 (MMB1) was carried out in the same manner as in the preparation of micro-adhesive adhesives. Masterbatch 6 (MMB6) was obtained.

(Preparation of micro masterbatch 7 (MMB7))

Micro masterbatch 1 (MMB1) except that masterbatch resin 1 was replaced with masterbatch resin 4 (60 parts by mass) and magenta pigment (pigment red 122) was replaced with black pigment (pigment black 7) (40 parts by mass) ), to obtain micro masterbatch 7 (MMB7) for pressure-sensitive adhesive.

(Preparation of micro masterbatch 8 (MMB8))

Micro masterbatch 1 (MMB1) except that masterbatch resin 1 was replaced with masterbatch resin 5 (60 parts by mass) and magenta pigment (pigment red 122) was replaced with black pigment (pigment black 7) (40 parts by mass) ), to obtain micro masterbatch 8 (MMB8) for pressure-sensitive adhesive.

<Example 1>

(Preparation of colored adhesive composition)

The MMB1 was added to the photopolymerizable composition so that the pigment concentration was 0.1% by mass, and mixed to obtain a colored pressure-sensitive adhesive composition.

(Manufacture of adhesive sheet)

A coating layer was formed by applying the colored pressure-sensitive adhesive composition to a thickness of 50 μm on the release-treated surface of a polyester film A (trade name “Diafoil MRF”, manufactured by Mitsubishi Chemical Corporation) having a thickness of 38 μm in which one side was subjected to release treatment with silicone, On the coating layer, after bonding the peeling treated surface of polyester film B (trade name "Diafoil MRF", manufactured by Mitsubishi Chemical Corporation) having a thickness of 38 μm to which one side was subjected to silicone peeling treatment, on the side of the polyester film B side directly under the lamp. Ultraviolet rays were irradiated by a UV-LED lamp whose lamp height was adjusted so that the intensity of the irradiation surface of 200 mW/cm ² was 200 mW/cm 2 . Polymerization was performed until it was irradiated with a light amount of 6000 mJ/cm ² to form a pressure-sensitive adhesive layer (colored pressure-sensitive adhesive) to prepare a pressure-sensitive adhesive sheet having a thickness of 50 μm.

<Example 2>

A colored PSA composition and PSA sheet of Example 2 were prepared in the same manner as in Example 1 except that MMB1 was added to the photopolymerizable composition so that the pigment concentration was 0.5% by mass and mixed.

<Example 3>

A colored PSA composition and PSA sheet of Example 3 were produced in the same manner as in Example 1 except that MMB1 was added to the photopolymerizable composition so that the pigment concentration was 1% by mass and mixed.

<Example 4>

The pigment dispersion 1 prepared above was added to the photopolymerizable composition so that the pigment concentration was 0.5% by mass, and mixed to obtain the colored pressure-sensitive adhesive composition of Example 4.

A pressure-sensitive adhesive sheet of Example 4 was prepared in the same manner as in Example 1.

<Example 5>

To the polymer solution containing the acrylic polymer of the pressure-sensitive adhesive composition 1, 0.3 parts by mass (in terms of solid content) of an isocyanate crosslinking agent (trade name "Takenate D160N", manufactured by Mitsui Chemicals Co., Ltd.) as a crosslinking agent per 100 parts by mass of the acrylic polymer, and as a crosslinking catalyst Dibutyltin dilaurate (trade name "OL-1", 1% by mass ethyl acetate solution (manufactured by Tokyo Fine Chemical Co., Ltd.) 0.01 parts by mass (solid content equivalent), and 4 parts by mass of acetylacetone as a crosslinking inhibitor (ligand for crosslinking catalyst) , MMB1 solution diluted with ethyl acetate so as to have a pigment concentration of 13.7% by mass was added and mixed so as to have a pigment concentration of 0.5% by mass, and the colored adhesive composition of Example 5 was obtained.

(Manufacture of adhesive sheet)

A coating film was formed by applying the colored pressure-sensitive adhesive composition to the peeling-treated surface of a 38 μm-thick polyester film A (trade name “Diafoil MRF”, manufactured by Mitsubishi Chemical Corporation), which had been subjected to a peeling treatment on one side with silicone. Next, this coating film was dried at 130°C for 3 minutes to form an adhesive layer having a thickness of 20 µm. To this pressure-sensitive adhesive layer, a release-treated surface of a polyester film B having a thickness of 38 µm (trade name "Diafoil MRF", manufactured by Mitsubishi Chemical Corporation) obtained by carrying out a silicone release treatment on one side was bonded. Thereafter, an aging treatment was performed at 60°C for 1 day to promote a crosslinking reaction in the pressure-sensitive adhesive layer.

<Example 6>

A solution of MMB4 diluted with ethyl acetate to a pigment concentration of 13.4% by mass was added to the polymer solution containing the acrylic polymer of the pressure-sensitive adhesive composition 1 so that the pigment concentration was 0.5% by mass, and it was carried out in the same manner as in Example 5 except that mixing was performed. The colored PSA composition and PSA sheet of Example 6 were produced.

<Example 7>

A solution of MMB5 diluted with ethyl acetate to a pigment concentration of 12.1% by mass was added to the polymer solution containing the acrylic polymer of the pressure-sensitive adhesive composition 1 so that the pigment concentration was 0.5% by mass, and it was carried out in the same manner as in Example 5 except that mixing was performed. The colored PSA composition and PSA sheet of Example 7 were produced.

<Example 8>

A solution of MMB6 diluted with ethyl acetate to a pigment concentration of 2.5% by mass was added to the polymer solution containing the acrylic polymer of the pressure-sensitive adhesive composition 2 to a pigment concentration of 1% by mass, and the mixture was carried out in the same manner as in Example 5 except that The colored PSA composition and PSA sheet of Example 8 were produced.

<Example 9>

A solution of MMB7 diluted with ethyl acetate to a pigment concentration of 2.5% by mass was added to the polymer solution containing the acrylic polymer of the pressure-sensitive adhesive composition 2 so that the pigment concentration was 1% by mass, and the mixture was carried out in the same manner as in Example 5 except that The colored PSA composition and PSA sheet of Example 9 were produced.

<Example 10>

A solution of MMB8 diluted with ethyl acetate to a pigment concentration of 2.5% by mass was added to the polymer solution containing the acrylic polymer of the pressure-sensitive adhesive composition 2 so that the pigment concentration was 1% by mass, and the mixture was carried out in the same manner as in Example 5 except that The colored PSA composition and PSA sheet of Example 10 were produced.

<Comparative Example 1>

The pigment dispersion 2 prepared above was added to the photopolymerizable composition so that the pigment concentration was 0.5% by mass, and mixed to obtain a colored pressure-sensitive adhesive composition of Comparative Example 1.

An adhesive sheet of Comparative Example 1 was produced in the same manner as in Example 1.

<Comparative Example 2>

A colored PSA composition and PSA sheet of Comparative Example 2 were produced in the same manner as in Example 1 except that MMB2 was added to the photopolymerizable composition so that the pigment concentration was 0.5% by mass and mixed.

<Comparative Example 3>

A colored PSA composition and PSA sheet of Comparative Example 3 were produced in the same manner as in Example 1 except that MMB3 was added to the photopolymerizable composition so that the pigment concentration was 0.5% by mass and mixed.

<Comparative Example 4>

The pigment dispersion 3 prepared above was added to the photopolymerizable composition so that the pigment concentration was 0.5% by mass, and mixed to obtain a colored pressure-sensitive adhesive composition of Comparative Example 4.

An adhesive sheet of Comparative Example 4 was prepared in the same manner as in Example 1.

<Comparative Example 5>

The pigment dispersion 4 prepared above was added to the photopolymerizable composition so that the pigment concentration was 0.5% by mass, and mixed to obtain a colored pressure-sensitive adhesive composition of Comparative Example 5.

An adhesive sheet of Comparative Example 5 was produced in the same manner as in Example 1.

<Comparative Example 6>

The colored PSA composition and PSA sheet of Comparative Example 6 were prepared in the same manner as in Example 5 except that the pigment dispersion 5 was added to the polymer solution containing the acrylic polymer of PSA composition 2 so that the pigment concentration was 1% by mass and mixed. made

Examples and comparative examples are shown in Table 2 and Table 3 below.

As shown in Table 2, the PSA sheets of Examples 1 to 10 had no in-plane color unevenness and exhibited good appearance, whereas Comparative Examples 1 to 3 and 5 had in-plane color unevenness and were poor in appearance. The PSA sheets of Examples 1 to 10 had a narrow standard deviation of transmittance of 0.37 to 1.10 at the wavelength at which the transmittance was the lowest at 400 to 800 nm, and had little in-plane color unevenness. As shown in Table 3, Comparative Examples 1 to 5 had a standard deviation of 1.20 to 2.41, which was wider than that of Examples, and showed that there were many in-plane color irregularities.

Further, as shown in Tables 2 and 3, the PSA sheets of Examples 1 to 10 exhibited high adhesion reliability with no decrease in adhesive force with time even under a high temperature and high humidity environment, but the PSA sheets of Comparative Examples 4 and 6. showed a decrease in adhesive strength with time under a high-temperature, high-humidity environment.

According to the present invention, a pressure-sensitive adhesive layer and pressure-sensitive adhesive sheet exhibiting excellent appearance and high adhesion reliability, a colored pressure-sensitive adhesive composition capable of forming the pressure-sensitive adhesive layer and pressure-sensitive adhesive sheet, a pigment dispersion masterbatch for pressure-sensitive adhesive having excellent dispersibility, and a pigment dispersion master for pressure-sensitive adhesive Resin for batches can be provided.

Although this invention was detailed also demonstrated with reference to the specific embodiment, it is clear for those skilled in the art that it is possible to add various changes and correction, without deviating from the mind and range of this invention.

This application is based on the Japanese Patent Application (Patent Application No. 2020-165632) filed on September 30, 2020, the contents of which are incorporated herein as a reference.

1, 2, 3: adhesive sheet
11, 21, 31a, 31b: pressure-sensitive adhesive layer
22, 32: description

Claims (5)

As a resin for pigment dispersion masterbatch for pressure-sensitive adhesive containing resin (A),
The glass transition temperature of the resin (A) is -80 to 40 ° C,
The acid value of the resin (A) is 1 to 50 (KOHmg / g),
Resin for pigment dispersion masterbatch for adhesives. Comprising the resin for the pigment dispersion masterbatch for the pressure-sensitive adhesive according to claim 1 and the pigment;
A pigment dispersion masterbatch for an adhesive wherein the content of the resin (A) is 45 to 90% by mass with respect to the total mass of the pigment and the resin (A). A colored pressure-sensitive adhesive composition comprising the pigment dispersion masterbatch for pressure-sensitive adhesive according to claim 2 and a base polymer. According to claim 3,
The colored pressure-sensitive adhesive composition in which the base polymer is an acrylic polymer. A pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive layer comprising the colored pressure-sensitive adhesive composition according to claim 3 or 4.

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