JP7347508B2 - Adhesive sheet for vacuum pressure forming and its use - Google Patents

Description

Cross-reference of related applications

This application is based on Japanese Patent Application No. 2019-115239 filed on June 21, 2019, and the contents thereof are incorporated herein.

The present disclosure relates to a pressure-sensitive adhesive sheet for vacuum-pressure forming and its use.

BACKGROUND ART Adhesives (also referred to as pressure-sensitive adhesives) are processed into forms such as tapes and labels, and are used in a wide range of applications. Moreover, it can be applied to various materials such as plastic, paper, metal, glass, and ceramics.

Furthermore, adhesives are also used in decorative films for the purpose of protecting components such as home appliances or automobile interior and exterior products, as well as imparting design features. As a method for forming a decorative film, in addition to in-mold molding using injection molding, methods of laminating or transferring the decorative film onto a molded product using vacuum forming, vacuum-pressure forming, etc. are used. Here, when forming by lamination, the decorative film has a structure in which a decorative layer, an adhesive layer, etc. are laminated on a base material layer made of a thermoplastic resin such as vinyl chloride resin or polyolefin resin. is used. In addition, when molding is performed by transfer, a laminate including a protective layer, a decoration layer, and an adhesive layer is transferred onto the surface of the molded product. A decorative film for vacuum forming having such an adhesive layer has been disclosed (Patent Documents 1 and 2).

JP2012-213891A Japanese Patent Application Publication No. 2012-213894

In the application of decorative films, it is required to follow complex shapes such as curved surfaces and uneven parts. For this reason, among the above-mentioned molding methods, "vacuum-pressure molding" is attracting attention. This is a method in which a decorative film made of thermoplastic resin is heated and softened, a vacuum is created between the mold or base material and the decorative film, and the decorative film is brought into close contact with the mold or base material using compressed air pressure. be.

However, when the decorative films for vacuum forming described in Patent Documents 1 and 2 are used for "vacuum-pressure forming", although the adhesion at room temperature is good, the decorative films after being attached to the base material have line-like formations. Appearance defects such as unevenness (so-called "shock lines" and "shock marks") may occur.

The present disclosure has been made in view of the above circumstances, and its purpose is to provide a pressure-sensitive adhesive sheet for vacuum-pressure forming that can suppress the generation of shock lines on a decorative film after being attached to a base material. An object of the present invention is to provide a decorative film and a decorative molded article equipped with the decorative film.

As a result of intensive studies to solve the above problem, the present inventors have found that the shock line can be suppressed by using a specific pressure-sensitive adhesive sheet for vacuum pressure forming. The present disclosure is as follows.

[1] It has an adhesive layer formed from an adhesive composition and a thin film layer, the thin film layer is disposed on at least one side of the adhesive layer, is thinner than the adhesive layer, and has a thin film layer. The melting point, softening point, or glass transition temperature (Tg) of the layer is 70°C or higher, or the thin film layer is a surface layer of the adhesive layer, and is obtained by X-ray photoelectron spectroscopy analysis of the adhesive layer. A pressure-sensitive adhesive sheet for vacuum-pressure forming, which has a Tg calculated from the composition of its surface layer portion of 70° C. or higher.
[2] The pressure-sensitive adhesive sheet for vacuum-pressure forming according to [1], wherein the pressure-sensitive adhesive composition is an acrylic pressure-sensitive adhesive composition.
[3] The acrylic adhesive composition includes a vinyl polymer (A) and an acrylic adhesive polymer (B), and the vinyl polymer (A) has a Tg of 30°C or more and 200°C or less, The adhesive layer has a number average molecular weight of 500 to 10,000, and is contained in an amount of 0.5 parts by mass or more and 60 parts by mass or less based on 100 parts by mass of the acrylic adhesive polymer (B). The first Tg, which is the Tg of the entire adhesive layer, is -80°C or more and 20°C or less, and the second Tg, which is the Tg calculated from the composition of the surface layer portion obtained by X-ray photoelectron spectroscopy analysis of the adhesive layer. The pressure-sensitive adhesive sheet for vacuum-pressure forming according to [2], wherein the Tg is 30° C. or more higher than the first Tg.
[4] The pressure-sensitive adhesive sheet for vacuum-pressure forming according to [3], which contains the vinyl polymer (A) at a higher concentration in at least one surface layer portion of the pressure-sensitive adhesive layer.
[5] Any one of [1] to [4], wherein the thin film layer contains at least one selected from the group consisting of polyolefin resin, rosin ester resin, polyester resin, and (meth)acrylic resin. 1. The pressure-sensitive adhesive sheet for vacuum-pressure forming as described in 1.
[6] A method for producing the pressure-sensitive adhesive sheet for vacuum-pressure forming according to any one of [1] to [5], comprising:
A method for producing a pressure-sensitive adhesive sheet for vacuum-pressure forming, comprising forming the thin film layer on a release film.
[7] A method for producing a pressure-sensitive adhesive sheet for vacuum-pressure forming, comprising the steps of forming a thin film layer, and applying a pressure-sensitive adhesive composition on the thin film layer to form a pressure-sensitive adhesive layer. A method for producing a pressure-sensitive adhesive sheet for vacuum-pressure forming, wherein the thin film layer is thinner than the pressure-sensitive adhesive layer, and the thin film layer has a melting point, softening point, or glass transition temperature (Tg) of 70° C. or higher.
[8] A decorative film comprising the pressure-sensitive adhesive sheet for vacuum-pressure forming according to any one of [1] to [5].
[9] A decorated molded article obtained by adhering the decorative film described in [8] to a molded article.

According to the pressure-sensitive adhesive sheet for vacuum-pressure forming of the present disclosure, it is possible to suppress the occurrence of shock lines in the decorative film after it is attached to a base material. Moreover, a decorated molded article including such a decorative film can be obtained.

Various embodiments of the technology disclosed in this specification will be described in detail below. In addition, in this specification, "(meth)acrylic" means acrylic and/or methacryl, and "(meth)acrylate" means acrylate and/or methacrylate. Moreover, "(meth)acryloyl group" means an acryloyl group and/or a methacryloyl group.

The pressure-sensitive adhesive sheet for vacuum-pressure forming of the present disclosure includes a pressure-sensitive adhesive layer formed from a pressure-sensitive adhesive composition and a thin film layer. The thin film layer of the pressure-sensitive adhesive sheet for vacuum-pressure forming of the present disclosure is the following [1] or [2].
[1] The thin film layer is disposed on at least one side of the adhesive layer, the thin film layer is thinner than the adhesive layer, and the melting point, softening point, or glass transition temperature (Tg) of the thin film layer is 70°C. That's all.
[2] The thin film layer is a surface layer of the adhesive layer, and has a Tg of 70° C. or higher calculated from the composition of the surface layer obtained by X-ray photoelectron spectroscopy of the adhesive layer.

The pressure-sensitive adhesive sheet for vacuum-pressure forming of the present disclosure is particularly effective when preforming at a temperature at which the adhesiveness of the thin film layer does not develop, and then vacuum-pressure forming at a temperature at which the adhesiveness of the thin film layer develops. Adhesive composition according to the present disclosure (hereinafter also referred to as "the present adhesive composition"), thin film layer according to the present disclosure (hereinafter also referred to as "the present thin film layer"), adhesive for vacuum pressure air forming of the present disclosure The details of the manufacturing method of the sheet (hereinafter referred to as "the present adhesive sheet"), the decorative film and the decorative molded article, and the preferred embodiments of the present adhesive composition will be explained in sequence.

1. This adhesive composition The type of this adhesive composition is not particularly limited as long as it satisfies the required performance according to the application such as adhesiveness, heat resistance, weather resistance, chemical resistance, etc. Acrylic adhesive composition compositions, polyester adhesive compositions, urethane adhesive compositions, silicone adhesive compositions, rubber adhesive compositions, and the like. Among these, acrylic pressure-sensitive adhesive compositions are preferred because of their excellent balance between durability and cost.

The acrylic adhesive composition preferably contains an acrylic adhesive polymer (B). Further, the acrylic adhesive composition preferably contains a vinyl polymer (A) and an acrylic adhesive polymer (B) having a specific glass transition temperature and number average molecular weight. When the acrylic pressure-sensitive adhesive composition contains a vinyl polymer (A) and an acrylic pressure-sensitive adhesive polymer (B), the vinyl polymer (A) is segregated to the surface layer of the pressure-sensitive adhesive layer. It is preferable to control the glass transition temperature of the surface layer portion.

Due to the segregation of the vinyl polymer (A) in the adhesive layer, the Tg calculated from the composition of the surface layer obtained by X-ray photoelectron spectroscopy of the adhesive layer is 30°C or more higher than the Tg of the entire adhesive layer. It is preferable to do so. This makes it possible to control the adhesive properties of the pressure-sensitive adhesive layer and obtain good adhesive strength. That is, since the adhesive has a relatively high Tg near the adhesive interface constituted by the surface layer of the adhesive, it is possible to exhibit excellent adhesiveness that has not been seen in the past. Furthermore, even under high temperatures, the adhesive layer can be prevented from shifting or peeling off, and can exhibit good durability. The segregation behavior of the vinyl polymer (A) on the surface layer of the adhesive layer is such that while the specific vinyl polymer (A) and the acrylic adhesive polymer (B) are not completely compatible, they are completely phase separated. It's based on what you don't do. Preferably, the vinyl polymer (A) has lower polarity than the acrylic adhesive polymer (B).

As the vinyl polymer (A), it is preferable to use a vinyl polymer that is not completely compatible with the acrylic adhesive polymer (B). At that time, the degree of segregation can be adjusted by appropriately adjusting the amount of vinyl polymer (A) used in the adhesive composition. If the amount of vinyl polymer (A) used is too small, segregation to the surface layer of the adhesive layer will be insufficient, and sufficient effects may not be obtained. On the other hand, if the amount of the vinyl polymer (A) used is too large, it tends to undergo phase separation from the acrylic adhesive polymer (B), resulting in a decrease in the transparency and adhesive performance of the adhesive layer. In addition, the glass transition temperature of the vinyl polymer (A), the amount of crosslinking agent, etc. are adjusted as appropriate, thereby making it possible to adjust the glass transition temperature of the surface layer portion of the adhesive layer. The vinyl polymer (A), acrylic adhesive polymer (B), and other components will be explained in detail in "5. Preferred embodiments of the present adhesive composition" below.

The thickness of the adhesive layer formed from the adhesive composition used in the present invention is appropriately selected depending on the type of the adhesive composition and the purpose of use, and is not particularly limited. For example, the average value of the entire layer is from 2 to 200 μm, for example from 15 to 100 μm, and for example from 20 to 70 μm.

2. This thin film layer This thin film layer has an adhesion surface to an adherend when the present adhesive sheet is adhered to an adherend by vacuum pressure forming. As mentioned above, this thin film layer is a layer that is disposed on at least one side of the adhesive layer, is thinner than the adhesive layer, and has a melting point, softening point, or Tg of 70°C or higher (hereinafter referred to as a thin film layer). (Also referred to as "thin film layer 1." The above thin film layer (hereinafter also referred to as "thin film layer 2"). The thickness of the thin film layer is appropriately selected depending on the purpose of use and is not particularly limited. The thickness of the thin film layer is, for example, 0.001 to 50 μm, for example, 0.005 to 20 μm, or, for example, 0.01 to 15 μm, as an average value of the entire thin film layer, and, for example, It is 0.01 to 10 μm.

Here, the pressure-sensitive adhesive sheet for vacuum-pressure forming having the present thin film layer is easy to handle because the present thin film layer has no to slight tackiness under low temperature conditions such as room temperature. In addition, the present adhesive sheet and the decorative film having the present adhesive sheet are preformed at a temperature at which the adhesiveness of the thin film layer does not develop (hereinafter also referred to as "first temperature"), and then the adhesiveness of the thin film layer is It has the characteristic that it is particularly effective when bonding to an adherend by heating and pressurizing at a temperature at which the adhesive properties are expressed (hereinafter also referred to as "second temperature"). When performing the above-mentioned pre-shaping, the steps from pre-shaping to adhesion may be performed in the same vacuum-pressure forming machine, or after performing the pre-shaping in a device different from the vacuum-pressure forming machine, vacuum-pressure forming can be performed. It may be put into a machine and bonded by heating and pressure. Examples of the vacuum-pressure forming machine include a hot plate vacuum coating machine (TFH series) manufactured by Asano Institute, a TOM forming machine (NGF series) manufactured by Fuse Vacuum, and a NATS air transfer machine manufactured by Navitas. Among these, the NATS air transfer machine, which can uniformly heat and pressurize the molded body with high-temperature steam, is preferable because it suppresses shock lines and exhibits high adhesiveness. Further, it is also possible to use a vacuum forming machine or a pressure forming machine having a principle similar to that of a vacuum forming machine.

The first temperature is, for example, less than 100°C, preferably 95°C or less. The lower limit of the first temperature is, for example, 20°C or higher, preferably 40°C or higher, and more preferably 50°C or higher. The second temperature may be any temperature higher than the first temperature, but is, for example, 100°C or higher, preferably 110°C or higher. The upper limit of the second temperature is, for example, 230°C or less, and preferably 200°C or less.

2-1． Thin film layer 1
The thin film layer 1 has a melting point, softening point, or Tg of 70° C. or higher. Examples of the thin film layer 1 include a thin film layer formed from a thermoplastic resin having a melting point, softening point, or Tg of 70° C. or higher. The thermoplastic resins include polyolefin resins, rosin ester resins, polyester resins, (meth)acrylic resins, terpene resins, petroleum resins such as styrene, ethylene/vinyl acetate resins, vinyl chloride/vinyl acetate, etc. Examples thereof include urethane-based resins, urethane-based resins, and adhesive compositions containing these resins. Among these, it is preferable to contain at least one selected from the group consisting of polyolefin resins, rosin ester resins, polyester resins, and (meth)acrylic resins, in terms of the great effects of the present disclosure; It is more preferable that the resin contains at least one selected from the group consisting of resins, rosin ester resins, and polyester resins, and polyolefin resins are particularly preferable.

The method for producing the thin film layer 1 is not particularly limited, but the composition containing the thermoplastic resin may be coated with a coating machine such as a gravure coater, a knife coater, or a slot die coater, or by gravure printing, offset printing, screen printing, inkjet printing, etc. A method of coating the base material using a printing machine is preferred. Among these, from the viewpoint of productivity, the method using a gravure coater is more preferable. Hereinafter, polyolefin resin, rosin ester resin, and polyester resin will be explained.

<Polyolefin resin>
Examples of polyolefin resins include ethylene, propylene, 1-butene, 1-pentene, 3-methyl-1-butene, 1-hexene, 3-methyl-1-pentene, 4-methyl-1-pentene, 1-heptene, α-olefins having 2 to 20 carbon atoms such as 4-methyl-1-hexene, 1-octene, 4,4-dimethyl-1-hexene, 1-nonene, 1-decene, 1-undecene, and 1-dodecene; Examples include homopolymers or copolymers of conjugated or non-conjugated dienes having 2 to 20 carbon atoms, such as butadiene, 1,5-hexadiene, ethylidene norbornene, and dicyclopentadiene. Further, ethylene/ethyl acrylate copolymer, ethylene/vinyl acetate copolymer, styrene/butadiene copolymer, styrene/isoprene copolymer, etc. may be used. When using a copolymer, a random copolymer, a block copolymer, or a graft copolymer can be appropriately selected. Moreover, two or more types of these polyolefins may be used in combination.

Preferred examples of polyolefin resins include polypropylene, propylene/ethylene copolymer, propylene/1-butene copolymer, propylene/ethylene/1-butene copolymer, and propylene/ethylene/1-octene copolymer. be able to. When using a propylene copolymer, the propylene content is preferably 50% by mass or more, more preferably 60% by mass or more, still more preferably 75% by mass or more, when the entire propylene copolymer is 100% by mass. It is.

The polyolefin resin is preferably a modified polyolefin resin because it has high adhesiveness to low polarity materials such as polypropylene. Examples of the modified polyolefin resin include acid-modified polyolefin resin, chlorinated polyolefin resin, carbodiimide-modified polyolefin resin, urea-modified polyolefin resin, and imine-modified polyolefin resin. These modifications may be made by sequentially performing two or more modifications. Specific examples of modified polyolefin resins that have been sequentially subjected to two or more modifications include acid-modified chlorinated polyolefin resins, acrylic-modified chlorinated polyolefin resins, urethane-modified chlorinated polyolefin resins, and the like. Among these, at least one selected from the group consisting of acid-modified polyolefin resins, chlorinated polyolefin resins, and acid-modified chlorinated polyolefin resins can be preferably used, and acid-modified polyolefin resins Particularly preferred.

The acid-modified polyolefin resin can be obtained by preferably graft copolymerizing an unsaturated carboxylic acid or an anhydride thereof to the above-mentioned polyolefin resin. Conventionally known methods can be used for this modification reaction, such as a method in which an unsaturated carboxylic acid or its anhydride is added to a polyolefin resin melted using an extruder and copolymerized, or a method in which polyolefin is dissolved in a solvent. A method of copolymerizing by adding an unsaturated carboxylic acid or its anhydride to a system resin, a method of copolymerizing by adding an unsaturated carboxylic acid or its anhydride to a polyolefin resin made into an aqueous suspension, etc. I can do it. Note that the modification site of the polyolefin chain by this modification reaction may be at one end or both ends of the molecular chain, may be in the middle of the molecular chain, or may be at multiple locations.

Examples of unsaturated carboxylic acids or anhydrides thereof that can be used in the above modification reaction include unsaturated monocarboxylic acids such as (meth)acrylic acid, crotonic acid, isocrotonic acid, and cinnamic acid, fumaric acid, maleic acid, citraconic acid, and chloromaleic acid. acids, unsaturated dicarboxylic acids such as glutaconic acid and itaconic acid, half esters or half amides of these unsaturated dicarboxylic acids, unsaturated tricarboxylic acids such as trans-anicottic acid, maleic anhydride, citraconic anhydride, chloro Examples include acid anhydrides such as maleic anhydride, itaconic anhydride, and 3,4,5,6-tetrahydrophthalic anhydride. Among these, (meth)acrylic acid, maleic acid and maleic anhydride are preferred, and maleic anhydride is particularly preferred.

The graft weight of maleic anhydride, etc. in the acid-modified polyolefin resin is preferably 0.1 to 20% by mass, more preferably 0.5 to 10% by mass when the entire acid-modified polyolefin resin is 100% by mass. Mass%. If the graft weight is within this range, the thin film layer 1 containing the acid-modified polyolefin resin exhibits high adhesion to both the adhesive layer formed from the adhesive composition and a low polarity material such as polypropylene. can do.

The acid-modified polyolefin resin may be one that has been modified using other modifiers in combination with the aforementioned unsaturated carboxylic acid or its anhydride during the modification reaction. Other modifiers include (meth)acrylic acid alkyl esters, functional group-containing (meth)acrylic acid alkyl esters, aromatic vinyl compounds, cyclohexyl vinyl ether, and the like.

Examples of (meth)acrylic acid alkyl esters include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, and (meth)acrylate. Hexyl acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, decyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, stearyl (meth)acrylate, (meth)acrylate Examples include acid cyclohexyl. These compounds may be used alone or in combination of two or more. In the present disclosure, it is preferable to use a modifier that further contains a (meth)acrylic acid ester having an alkyl group having 8 to 18 carbon atoms, and in particular, octyl (meth)acrylate, It is preferable that lauryl (meth)acrylate, tridecyl (meth)acrylate, or stearyl (meth)acrylate is included.

Examples of functional group-containing (meth)acrylic acid alkyl esters include hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, glycidyl (meth)acrylate, and isocyanate-containing (meth)acrylic ester. . Examples of the aromatic vinyl compound include benzyl (meth)acrylate, styrene, o-methylstyrene, p-methylstyrene, α-methylstyrene, and the like. By using an unsaturated carboxylic acid or its anhydride together with another modifier as the modifier, the grafting rate by the modifier can be improved and the adhesiveness can be further improved.

The graft weight of the modified polyolefin resin with other modifiers is preferably 0.1 to 20% by mass, more preferably 0.5 to 10% by mass when the entire acid-modified polyolefin resin is 100% by mass. It is. If the graft weight is within this range, it is possible to improve the grafting rate using a modifier such as maleic anhydride, and to exhibit high adhesiveness of the thin film layer 1. Note that the graft weight can be determined by a known method such as Fourier transform infrared spectroscopy.

The weight average molecular weight of the modified polyolefin resin is preferably 3,000 to 500,000, more preferably 25,000 to 250,000. If the weight average molecular weight of the acid-modified polyolefin resin is 3,000 or more, the heat resistance will be good, and if it is 500,000 or less, the solubility in a solvent will be improved and the handleability will be excellent.

It is preferable to use a modified polyolefin resin having a melting point or softening point of 70° C. or higher from the viewpoint of suppressing the generation of shock lines in the decorative film during vacuum-pressure molding and from the viewpoint of heat resistance. The melting point or softening point of the modified polyolefin resin is more preferably 80°C or higher, and even more preferably 90°C or higher. On the other hand, if the melting point or softening point is too high, the wettability to the adherend will be poor, so it is preferable that the melting point or softening point is 160° C. or lower.

Furthermore, instead of the acid-modified polyolefin resin, a copolymer in which a carboxylic acid and/or acid anhydride structure is incorporated in the basic skeleton of a polyolefin resin may be used, such as ethylene/acrylic acid/maleic anhydride. A terpolymer or the like may also be used.

Commercially available products may be used as the modified polyolefin resin. Specifically, the thin film layer 1 can be formed using a commercially available modified polyolefin resin used as a plastic surface modifier, a primer for automobile plastic base materials, a primer for electronics base materials, a primer for construction materials, etc. can. Alternatively, the thin film layer 1 may be formed using an adhesive composition containing a modified polyolefin resin.

Specifically, examples of the acid-modified polyolefin resin include Admer AT1000 and HE810 manufactured by Mitsui Chemicals, Inc., and Toyotac PMA-L and PMA-T manufactured by Toyobo Co., Ltd. Examples of the chlorinated polyolefin resin include Superklon 814HS and 390S manufactured by Nippon Paper Industries, Ltd., and Hardren 13-LP and 13-LLP manufactured by Toyobo Co., Ltd. Examples of acid-modified chlorinated polyolefin resins include Superklon 3228S and 2319S manufactured by Nippon Paper Industries, Ltd., and Hardren HM-21P manufactured by Toyobo Co., Ltd. Examples of the acrylic-modified chlorinated polyolefin resin include Superchron 224H and 240H manufactured by Nippon Paper Industries, Ltd. Examples of the terpolymer of ethylene/acrylic acid/maleic anhydride include the Bondine series manufactured by Arkema. These modified polyolefin resins may be used alone or in combination of two or more. Examples of adhesive compositions containing modified polyolefin resins include PPET-1303, PPET-1405SG, and PPET-1505SG manufactured by Toagosei Co., Ltd.

<Rosin ester resin>
Examples of the rosin ester resin include disproportionated rosin ester resin, hydrogenated rosin ester resin, and polymerized rosin ester resin. Commercially available products may be used, and examples of the disproportionated rosin ester resin include Superester A-100, A-115, and A-125 manufactured by Arakawa Chemical Industries, Ltd. Examples of the hydrogenated rosin ester resin include Pine Crystal KE-604, KE-140, and KE-311 manufactured by Arakawa Chemical Industry Co., Ltd. Examples of polymerized rosin ester resins include Pencel A, Pencel C, Pencel D-125, Pencel D-135, and Pencel D-160 manufactured by Arakawa Chemical Industries, Ltd.

<Polyester resin>
Examples of the polyester resin include condensation type polymers or copolymers having dicarboxylic acid units and diol units as constituent units.

Examples of raw materials used to form dicarboxylic acid units include aromatic dicarboxylic acids or dialkyl or diaryl esters thereof. Specific examples of aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, phthalic acid, naphthalene 1,4-dicarboxylic acid, naphthalene 2,6-dicarboxylic acid, bis(p-carboxyphenyl)methane, anthracenedicarboxylic acid, 4, Examples include 4'-diphenyl dicarboxylic acid and 4,4'-diphenyl ether dicarboxylic acid. Further, an aliphatic dicarboxylic acid or a dialkyl ester or diaryl ester thereof can also be used in combination. Specific examples of aliphatic dicarboxylic acids include glutaric acid, adipic acid, sebacic acid, oxalic acid, and succinic acid.
Specific examples of raw materials used to form the diol unit include ethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, decamethylene Examples include glycol, 1,4-cyclohexanedimethanol, 2,2-bis(4-hydroxyphenyl)propane, polyethylene glycol, poly-1,3-propylene glycol, and polytetramethylene glycol.

Among the polyester resins, crystalline homopolyethylene terephthalate resins and crystalline copolyester resins containing terephthalic acid units and/or isophthalic acid units as dicarboxylic acid units and ethylene glycol units as diol units are preferred. Further, an amorphous copolyester resin containing a terephthalic acid unit as a dicarboxylic acid unit and an ethylene glycol unit and a 1,4-cyclohexanedimethanol unit as a diol unit is preferable. Other polyester resins include polybutylene terephthalate, polyethylene-2,6-naphthalate, biodegradable polyester resins, and the like. These polyester resins can be used alone or in combination of two or more.

As the method for producing the polyester resin, any method can be adopted, such as the so-called direct polymerization method in which a dicarboxylic acid and a diol are directly reacted, and the so-called transesterification method in which a dimethyl ester of a dicarboxylic acid and a diol are transesterified. be able to.
As the polyester resin, a commercially available product may be used, or an adhesive composition containing a polyester resin may be used. Specific examples include Pluscoat Z-730 manufactured by Gooh Kagaku Kogyo Co., Ltd. and Byron 237, 290, and 296 manufactured by Toyobo Co., Ltd. Examples of adhesive compositions containing polyester resins include Aronmelt PES-320SK, PES-360HVXM30, and PES-310S30 manufactured by Toagosei Co., Ltd.

The melting point, softening point, or Tg of the thermoplastic resin forming the thin film layer 1 is preferably 70° C. or higher. It is preferable that the melting point, softening point, or Tg of the thermoplastic resin is 70° C. or higher, since it is possible to suppress the occurrence of shock lines in the decorative film during vacuum-pressure molding and to improve heat resistance. The melting point, softening point, or Tg of the thermoplastic resin forming the thin film layer 1 is more preferably 80°C or higher, and even more preferably 90°C or higher. On the other hand, if the melting point, softening point or Tg is too high, the wettability to the adherend may be poor. Therefore, it is preferable that the melting point, softening point, or Tg of the thermoplastic resin is 160° C. or lower. Note that the melting point and Tg of the thermoplastic resin forming the thin film layer 1 are based on JIS K7121, and the values measured by DSC at a temperature increase rate of 10° C./min are adopted. For the softening point, the value of the ring and ball method based on JIS K6863 is adopted. However, the softening point of the rosin ester resin is determined by the ring and ball method according to JIS K5902.

The weight average molecular weight of the thermoplastic resin forming the thin film layer 1 is preferably 3,000 to 500,000, more preferably 25,000 to 250,000. If the weight average molecular weight of the thermoplastic resin forming the thin film layer 1 is 3,000 or more, the heat resistance will be good, and if it is 500,000 or less, the solubility in a solvent will improve and the handleability will be excellent.
The thickness of the thin film layer 1 is not particularly limited as long as it is thinner than the adhesive layer. The thickness of the thin film layer 1 is, for example, 0.01 to 50 μm, preferably 0.1 to 20 μm, and more preferably 0.3 to 15 μm, as an average value of the entire thin film layer 1.

2-2. Thin film layer 2
As the thin film layer 2, an acrylic adhesive composition containing a vinyl polymer (A) and an acrylic adhesive polymer (B) having a specific glass transition temperature and number average molecular weight is used in order to achieve the effects of the present disclosure. In the product, it is particularly preferable that the surface layer portion of the adhesive layer is obtained by segregating the vinyl polymer (A) to the surface layer of the adhesive layer.

3. Manufacturing method of the present pressure-sensitive adhesive sheet The present pressure-sensitive adhesive sheet has a thin film layer 1 on at least one side of the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition, or constitutes a surface layer portion of the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition. It has a thin film layer 2. That is, the above-mentioned thin film layer 1 is provided on one or both sides, the entire surface or a part of the adhesive layer made of the adhesive composition, or at least one surface layer portion of the adhesive layer made of the adhesive composition. It has a thin film layer 2.

As a method for manufacturing the present pressure-sensitive adhesive sheet having the thin film layer 1, for example, the thin film layer 1 formed on a release film (hereinafter also referred to as a "separator") is bonded to a pressure-sensitive adhesive layer formed from a pressure-sensitive adhesive composition. By transferring to the surface, the thin film layer 1 can be formed on the surface of the adhesive layer formed from the adhesive composition (transfer method). For example, the thin film layer 1 may be formed on the surface of the adhesive layer formed from the adhesive composition by overcoating the adhesive composition on the thin film layer 1 formed on the separator. (layered coating method). Among these manufacturing methods, the overcoating method is more preferable because it tends to provide high peel strength to the adherend and can reduce the number of release films used. In addition, as a manufacturing method of the present adhesive sheet having the thin film layer 1, after creating the present adhesive sheet having the thin film layer 2, the thin film layer 1 may be formed on the thin film layer 2.

On the other hand, the method for producing the present adhesive sheet having the thin film layer 2 includes the step of containing a vinyl polymer (A) and an acrylic adhesive polymer (B) having a specific glass transition temperature and number average molecular weight on a separator. It is obtained by coating and forming an acrylic pressure-sensitive adhesive composition to segregate the vinyl polymer (A) to the surface layer of the pressure-sensitive adhesive layer. In this case, the surface layer portion functions as a thin film layer of the present disclosure.

A laminate can be formed by heat-pressing the thin film layer side of the pressure-sensitive adhesive sheet produced as described above to an adherend. When this adhesive sheet has a thin film layer on one side of the adhesive layer formed from the adhesive composition, or when the surface layer on one side of the adhesive layer is composed of a thin film layer, the adhesive layer side It is also possible to laminate a decorative film or the like. In addition, when the present adhesive sheet has thin film layers on both sides of the adhesive layer formed from the adhesive composition, or when the surface layer portions on both sides of the adhesive layer are composed of thin film layers, the adherend may They can also be laminated so that the present adhesive sheet is sandwiched therebetween. By forming the thin film layer on the separator, it is possible to obtain a pressure-sensitive adhesive sheet with a separator in which the thin film layer is disposed adjacent to the separator.

4. Decorative film and decorative molded body
4-1. The decorative film adhesive sheet can constitute the adhesive layer of the decorative film. The decorative film equipped with this adhesive sheet (hereinafter also referred to as "this decorative film") exhibits high adhesion under high temperature conditions and can suppress shock lines of the decorative film after being attached to the base material. .

In addition to the above-mentioned adhesive layer, the present decorative film can include a decoration layer and a base material layer. A decorative film having such a configuration can be suitably used when laminating a molded product to obtain a decorated molded product (laminate method).

After the decorative film is applied to the molded product, the base layer is located at the outermost layer of the decorated molded product, which will be described later, and functions as a protective layer of the decorated molded product. The material constituting the base layer may be any flexible material, and plastic is preferred. More preferably, it is a thermoplastic. Examples of thermoplastic plastics include, but are not particularly limited to, vinyl chloride (PVC) resins, polyester resins, (meth)acrylic resins, ABS resins, polycarbonate resins, polypropylene resins, and polyethylene resins. Among these, PVC resin, polyester resin, (meth)acrylic resin, and ABS resin are preferable as materials used for the base layer.

The thickness of the base material layer is preferably 25 μm to 500 μm, more preferably 50 μm to 400 μm, and even more preferably 100 to 300 μm. If the thickness of the base layer is within the above range, the processability, shape followability, and handleability will be good when producing the decorative molded product by vacuum-pressure forming.

The decorative layer is a layer provided to impart design to the decorative film, and is formed by printing or the like with designs such as texts, figures, patterns, and trademarks. The pattern formed on the decoration layer can be formed by a known printing method such as gravure printing using printing ink, offset printing, silk screen printing, transfer printing from a transfer sheet, sublimation transfer printing, and inkjet printing.

The thickness of the decorative layer is preferably 1 to 40 μm, more preferably 1 to 30 μm. When the thickness of the decorative layer is within the above range, a sufficient thickness can be ensured to express complex designs such as gradation. For the purpose of improving the design of the decorative film, an uneven pattern may be provided on the surface of the decorative film. The uneven pattern can be transferred by passing it through an embossing roller with an uneven pattern.

In order to improve the weather resistance, chemical resistance, stain resistance, abrasion resistance, electrical insulation properties, etc. of the decorative film, the decorative film can also be provided with a protective layer on the outermost surface. The protective layer may be coated with a polymeric material having the above-mentioned properties, or may be formed by laminating films having the above-mentioned properties. The protective layer may be the base layer.

The decorative film may further include a release layer. The peeling layer prevents unintended adhesion, and is peeled off when the decorative film is adhered to the molded article. The material constituting the release layer is not particularly limited, but includes, for example, polyester films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; plastic films such as polyolefin films such as polypropylene and polyethylene; glassine paper, kraft paper, and clay coated paper. Materials such as paper can be used. The thickness of these can be approximately 10 to 400 μm.

In addition to the above, the present decorative film may also have a structure in which a release film is provided with a release layer, and a hard coat layer (protective layer), a decoration layer, and an adhesive layer are provided on the release layer. . A decorative film having such a configuration can be suitably used as a transfer film, and a decorated molded product can be obtained by transferring everything from the hard coat layer to the adhesive layer onto the molded product (transfer method). In the case of the above-mentioned lamination method, it is necessary to remove the excess film by trimming after decorative molding, but in the transfer method, trimming is not necessary, which is advantageous in terms of production efficiency.

The above-mentioned hard coat layer is in a tack-free state before being transferred, and after being transferred to the molded product, it is made of a material that can be cured and/or crosslinked by irradiation with active energy rays, etc. Preferably, the configuration is configured. Examples of the material constituting the hard coat layer include a polymer or oligomer having a (meth)acryloyl group, an active energy ray-curable composition irradiated with an appropriate amount of active energy rays to a semi-cured state, or an active energy ray-curable composition Examples include those obtained by blending an isocyanate compound, a polyol resin, etc. with a line-curable resin composition and appropriately crosslinking it. The thickness of the hard coat layer is not particularly limited, but can be about 1 to 50 μm, preferably about 2 to 40 μm.

4-2. Decorated Molded Body According to the present disclosure, a decorated molded body (hereinafter also referred to as "this decorated molded body") including the present decorative film is provided. Since the present decorative molded article is equipped with a decorative film having the adhesive sheet for vacuum-pressure forming of the present disclosure, it exhibits high adhesion under high temperature conditions and reduces the shock line of the decorative film after being attached to the base material. It can be suppressed.

The molded object to which the decorative film is adhered is not particularly limited, and may be any article to which the decorative film can be adhered, such as resin products, metal products, ceramic products, glass products, etc. can be mentioned. Specifically, for example, various home appliances such as household appliances, kitchen appliances, health appliances, and seasonal appliances; housing equipment such as toilets, bathrooms, doors, and walls; and automobile interiors such as bumpers, dashboards, doors, roofs, and hoods. various miscellaneous goods such as miscellaneous goods and daily necessities; electronic parts, nursing care and medical supplies, interior and exterior parts of ships, interior and exterior parts of aircraft, etc.

As mentioned above, the vacuum-pressure forming method can be used to manufacture the present decorative molded product. In the vacuum-pressure forming method, a decorative film that has been softened by heating under reduced pressure is brought into contact with an adherend under reduced pressure, and then the space on the opposite side of the adherend is pressurized to form the decorative film. Adhesion is performed while molding along the surface shape of the molded object.

5. Preferred embodiments of the present adhesive composition As described above, the present adhesive composition preferably contains an acrylic adhesive polymer (B), and a vinyl polymer (A) and an acrylic adhesive polymer (B). It is more preferable to contain it. Preferred embodiments of the vinyl polymer (A), the acrylic adhesive polymer (B), and the present adhesive layer will be described below.

5-1. Vinyl polymer (A)
The vinyl polymer (A) disclosed herein is preferably a polymer having a glass transition temperature (Tg) of 30°C or higher and 200°C or lower. The lower limit of Tg may be 40°C or higher, 50°C or higher, 60°C or higher, or 70°C or higher. The upper limit of Tg may be 180°C or less, 150°C or less, 120°C or less, or 110°C or less. Further, the range of Tg can be a combination of these upper and lower limits as appropriate, but is, for example, 40°C or more and 180°C or less, and preferably 60°C or more and 150°C or less. In this specification, the Tg of the vinyl polymer (A) is determined by differential scanning calorimetry (DSC) at a heating rate of 10° C./min. If the Tg is less than 30° C., the Tg of the surface layer portion of the pressure-sensitive adhesive layer will not be sufficiently high, and the adhesive strength to various adherends may be insufficient, resulting in poor durability. Further, due to restrictions on raw material monomers, etc., Tg is generally 200° C. or less.

As the monomer constituting the vinyl polymer (A), various vinyl-based unsaturated compounds having radical polymerizability can be used, such as (meth)acrylic acid-based compounds, aromatic vinyl compounds, unsaturated Carboxylic acids, unsaturated acid anhydrides, hydroxyl group-containing unsaturated compounds, amino group-containing unsaturated compounds, amide group-containing unsaturated compounds, alkoxyl group-containing unsaturated compounds, cyano group-containing unsaturated compounds, nitrile group-containing unsaturated compounds , maleimide compounds, and the like. These compounds may be used alone or in combination of two or more.

Among these, it is preferable to use (meth)acrylic acid-based compounds as the main component since appropriate compatibility with acrylic adhesive polymers can be obtained. The specific amount of the (meth)acrylic acid compound used in the total monomer composition of the vinyl polymer (A) is, for example, in the range of 10% by mass or more and 100% by mass or less, and 30% by mass or more and 95% by mass. % or less, or 50% by mass or more and 90% by mass or less. The lower limit of the amount used may be 40% by mass or more, or 50% by mass or more. Further, the upper limit of the amount used may be 90% by mass or less, or 80% by mass or less.

Examples of (meth)acrylic acid compounds include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, and n-butyl (meth)acrylate. , isobutyl (meth)acrylate, tert-butyl (meth)acrylate, amyl (meth)acrylate, n-hexyl (meth)acrylate, n-octyl (meth)acrylate, ethylhexyl (meth)acrylate, ( (meth)acrylic acid alkyl esters such as n-dodecyl meth)acrylate and n-octadecyl (meth)acrylate; cyclohexyl (meth)acrylate, methylcyclohexyl (meth)acrylate, tert-butyl (meth)acrylate Aliphatic vinyl monomers such as cyclohexyl, cyclododecyl (meth)acrylate, isobornyl (meth)acrylate, adamantyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentanyl (meth)acrylate, etc. Polymer: aromatic ring-based vinyl polymers such as phenyl (meth)acrylate and benzyl (meth)acrylate. These compounds may be used alone or in combination of two or more.

Among these, (meth) can be set relatively high, has a high effect of suppressing lifting and peeling of the adhesive sheet, and has good adhesion of the olefin polymer to the adherend. ) It is preferable to use aliphatic cyclic vinyl monomers such as isobornyl acrylate, dicyclopentanyl (meth)acrylate, cyclohexyl (meth)acrylate, and adamantyl (meth)acrylate. The specific usage amount of the aliphatic cyclic vinyl monomer is preferably 1% by mass or more, more preferably 5% by mass or more, and 10% by mass or more based on the total constituent monomers of the vinyl polymer (A). is even more preferable. The upper limit of the amount of the aliphatic cyclic vinyl monomer used is preferably 90% by mass or less, more preferably 80% by mass or less, based on the total constituent monomers of the vinyl polymer (A). The amount of the aliphatic cyclic vinyl monomer used is preferably 1% by mass or more and 90% by mass or less, and 5% by mass or more and 80% by mass based on the total constituent monomers of the vinyl polymer (A). The following is more preferable, and 10% by mass or more and 70% by mass or less is even more preferable.

Examples of aromatic vinyl compounds include styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, vinyltoluene, β-methylstyrene, ethylstyrene, p-tert-butylstyrene, vinylxylene, vinylnaphthalene, etc. can be mentioned. These compounds may be used alone or in combination of two or more. When an aromatic vinyl compound is used as a monomer constituting the vinyl polymer (A), the specific amount of the aromatic vinyl compound to be used is 1% to the total monomers constituting the vinyl polymer (A). The range is preferably from 5% by mass to 40% by mass, more preferably from 5% by mass to 30% by mass, and even more preferably from 5% by mass to 20% by mass.

Examples of unsaturated carboxylic acids include (meth)acrylic acid, ethacrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, citraconic acid, cinnamic acid, and monoalkyl esters of unsaturated dicarboxylic acids (maleic acid, etc.). , monoalkyl esters of fumaric acid, itaconic acid, citraconic acid, maleic anhydride, itaconic anhydride, citraconic anhydride, etc.). These compounds may be used alone or in combination of two or more.
Examples of the unsaturated acid anhydride include maleic anhydride, itaconic anhydride, citraconic anhydride, and the like. These compounds may be used alone or in combination of two or more.

Examples of the hydroxyl group-containing unsaturated compound include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 2-hydroxybutyl (meth)acrylate. , 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, mono(meth)acrylate ester of polyalkylene glycol such as polyethylene glycol, polypropylene glycol, p-hydroxystyrene, m-hydroxystyrene , o-hydroxystyrene, p-isopropenylphenol, m-isopropenylphenol, o-isopropenylphenol and the like. These compounds may be used alone or in combination of two or more.

Examples of the amino group-containing unsaturated compound include dimethylaminomethyl (meth)acrylate, diethylaminomethyl (meth)acrylate, 2-dimethylaminoethyl (meth)acrylate, 2-diethylaminoethyl (meth)acrylate, ( 2-(di-n-propylamino)ethyl meth)acrylate, 2-dimethylaminopropyl (meth)acrylate, 2-diethylaminopropyl (meth)acrylate, 2-(di-n-propyl (meth)acrylate) Examples include amino)propyl, 3-dimethylaminopropyl (meth)acrylate, 3-diethylaminopropyl (meth)acrylate, and 3-(di-n-propylamino)propyl (meth)acrylate. These compounds may be used alone or in combination of two or more.

Examples of the amide group-containing unsaturated compound include (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-dimethylaminopropyl(meth)acrylamide, and N-methylol(meth)acrylamide. These compounds may be used alone or in combination of two or more.

Examples of the alkoxyl group-containing unsaturated compound include 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2-(n-propoxy)ethyl (meth)acrylate, and (meth)acrylic acid. 2-(n-butoxy)ethyl, 3-methoxypropyl (meth)acrylate, 3-ethoxypropyl (meth)acrylate, 2-(n-propoxy)propyl (meth)acrylate, 2-(meth)acrylate Examples include (n-butoxy)propyl. These compounds may be used alone or in combination of two or more.

Examples of the cyano group-containing unsaturated compound include cyanomethyl (meth)acrylate, 1-cyanoethyl (meth)acrylate, 2-cyanoethyl (meth)acrylate, 1-cyanopropyl (meth)acrylate, and (meth)acrylate. 2-cyanopropyl acid, 3-cyanopropyl (meth)acrylate, 4-cyanobutyl (meth)acrylate, 6-cyanohexyl (meth)acrylate, 2-ethyl-6-cyanohexyl (meth)acrylate, ( Examples include 8-cyanooctyl meth)acrylate. These compounds may be used alone or in combination of two or more.

Examples of the nitrile group-containing unsaturated compound include (meth)acrylonitrile, α-ethyl acrylonitrile, α-isopropylacrylonitrile, α-chloroacrylonitrile, α-fluoroacrylonitrile, and the like. These compounds may be used alone or in combination of two or more.

Examples of maleimide compounds include maleimide, N-methylmaleimide, N-isopropylmaleimide, N-butylmaleimide, N-dodecylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, N-(2-methylphenyl)maleimide, Examples include N-(4-methylphenyl)maleimide, N-(2,6-dimethylphenyl)maleimide, N-(2,6-diethylphenyl)maleimide, N-benzylmaleimide, N-naphthylmaleimide, and the like. These compounds may be used alone or in combination of two or more.

In addition to the above compounds, dialkyl esters of unsaturated dicarboxylic acids, vinyl ester compounds, vinyl ether compounds, etc. can also be used. Examples of dialkyl esters of unsaturated dicarboxylic acids include dialkyl esters such as maleic acid, fumaric acid, itaconic acid, citraconic acid, maleic anhydride, itaconic anhydride, and citraconic anhydride. Examples of the vinyl ester compound include methylene aliphatic monocarboxylic acid ester, vinyl acetate, vinyl propionate, vinyl pivalate, vinyl butyrate, vinyl benzoate, vinyl formate, vinyl cinnamate, and the like. Examples of the vinyl ether compound include vinyl methyl ether, vinyl ethyl ether, vinyl-n-butyl ether, vinyl isobutyl ether, vinyl phenyl ether, vinyl cyclohexyl ether, and the like.

The number average molecular weight (Mn) of the vinyl polymer (A) can be 500 or more and 10,000 or less. The Mn of the vinyl polymer (A) is preferably 500 or more, more preferably 1,000 or more, and even more preferably 2,000 or more. The upper limit of Mn in the vinyl polymer (A) is preferably 10,000 or less, more preferably 8,000 or less, and even more preferably 7,000 or less. Mn may be 500 or more and 7,000 or less, or 1,000 or more and 5,000 or less. When Mn exceeds 10,000, compatibility with the acrylic adhesive polymer (B) may deteriorate. On the other hand, in order to produce a polymer having an Mn of less than 500, it may be necessary to use a large amount of a polymerization initiator or a chain transfer agent, and there may be a decrease in productivity.

Further, the ratio (Mw/Mn) between the weight average molecular weight (Mw) and the above (Mn) is preferably 3.0 or less from the viewpoint of easily obtaining good adhesive strength. More preferably it is 2.5 or less, still more preferably 2.0 or less, even more preferably 1.8 or less. Note that the weight average molecular weight Mw and the number average molecular weight Mn are standard polystyrene equivalent values obtained using gel permeation chromatography (GPC).

Although there are no particular restrictions on the method of producing the vinyl polymer (A), it can be easily obtained, for example, by polymerizing the above monomers using a known radical polymerization method such as a solution polymerization method. . When using the solution polymerization method, an organic solvent and vinyl monomer raw materials are charged into a reactor, a thermal polymerization initiator such as an organic peroxide or an azo compound is added, and the mixture is heated to 50 to 300°C to copolymerize. By doing this, the desired vinyl polymer can be obtained. The vinyl polymer may be used as a solution dissolved in an organic solvent, or may be used after the solvent is distilled off by heating under reduced pressure or the like.

The method for charging each raw material including monomers may be batch-type initial batch charging in which all raw materials are charged at once, or semi-continuous charging in which at least one raw material is continuously fed into the reactor. A continuous polymerization method may be used in which the raw materials are continuously supplied and at the same time, the produced resin is continuously extracted from the reactor.

Suitable organic solvents used in the solution polymerization method are organic hydrocarbon compounds, including cyclic ethers such as tetrahydrofuran and dioxane, aromatic hydrocarbon compounds such as benzene, toluene and xylene, and ethyl acetate and butyl acetate. Examples include esters, ketones such as acetone, methyl ethyl ketone, and cyclohexanone, and alcohols such as methyl orthoformate, methyl orthoacetate, methanol, ethanol, and isopropanol, and one or more of these may be used. Among these organic solvents, ethyl acetate, butyl acetate, acetone, and methyl ethyl ketone are preferable because they dissolve the vinyl polymer well and have a relatively low boiling point for easy purification.

The initiator used herein may be an azo compound, an organic peroxide, an inorganic peroxide, etc., but is not particularly limited. A redox type polymerization initiator consisting of a known oxidizing agent and reducing agent may be used. Moreover, a known chain transfer agent can also be used in combination.

Examples of azo compounds include 2,2'-azobis(isobutyronitrile), 1,1-azobis(cyclohexane-1-carbonitrile), azocumene, and 2,2'-azobis(2-methylbutyronitrile). ), 2,2'-azobisdimethylvaleronitrile, 4,4'-azobis(4-cyanovaleric acid), 2-(tert-butylazo)-2-cyanopropane, 2,2'-azobis(2,4 , 4-trimethylpentane), 2,2'-azobis(2-methylpropane), dimethyl 2,2'-azobis(2-methylpropionate), and the like.

Examples of organic peroxides include cyclohexanone peroxide, 3,3,5-trimethylcyclohexanone peroxide, methylcyclohexanone peroxide, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane , 1,1-bis(tert-butylperoxy)cyclohexane, n-butyl-4,4-bis(tert-butylperoxy)valerate, cumene hydroperoxide, 2,5-dimethylhexane-2,5-di Hydroperoxide, 1,3-bis[(tert-butylperoxy)-m-isopropyl]benzene, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, diisopropylbenzene peroxide, tert -Butylcumyl peroxide, decanoyl peroxide, lauroyl peroxide, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, bis(tert-butylcyclohexyl) peroxydicarbonate, tert-butyl peroxybenzoate, 2,5 -dimethyl-2,5-di(benzoylperoxy)hexane and the like.
Examples of the inorganic peroxide include potassium persulfate, sodium persulfate, ammonium persulfate, and the like.

Examples of redox-type polymerization initiators include sodium sulfite, sodium thiosulfate, sodium formaldehyde sulfoxylate, ascorbic acid, ferrous sulfate, etc., and potassium peroxodisulfate, hydrogen peroxide, tert-butyl hydroperoxide, etc. An oxidizing agent such as oxide can be used.

In order to adjust the molecular weight of the vinyl polymer (A), a known chain transfer agent may be used as necessary. Chain transfer agents include ethanethiol, butanethiol, dodecanethiol, benzenethiol, toluenethiol, α-toluenethiol, phenethylmercaptan, mercaptoethanol, 3-mercaptopropanol, thioglycerin, thioglycolic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, α-mercaptoisobutyric acid, methyl mercaptopropionate, ethyl mercaptopropionate, thioacetic acid, thiomalic acid, thiosalicylic acid, octyl mercaptan, n-dodecyl mercaptan, tert-dodecyl mercaptan, n-hexadecyl mercaptan, Examples include n-tetradecyl mercaptan and tert-tetradecyl mercaptan.

The vinyl polymer (A) can also be obtained by continuous polymerization in a temperature range of 180 to 350°C using a stirred tank reactor. With this polymerization method, a relatively low molecular weight vinyl polymer can be obtained without using a polymerization initiator or a chain transfer agent, resulting in a highly pure polymer, and there are no problems with coloration or odor, which will be discussed later. However, it is preferable because it is advantageous. If the polymerization temperature is less than 180° C., a polymerization initiator and a large amount of chain transfer agent are required for the polymerization reaction, and the resulting copolymer is likely to be colored and generate an undesirable odor. On the other hand, if the polymerization temperature exceeds 350°C, a decomposition reaction is likely to occur during the polymerization reaction, and the resulting copolymer will be colored, which may reduce the transparency of the adhesive layer obtained from the adhesive composition containing it. There are concerns about a decline. Furthermore, according to such a polymerization method, a vinyl polymer having a narrow molecular weight distribution range can be obtained. The polymerization initiator may be optionally used, but it is preferably used in an amount of about 1% by mass or less based on the total monomers.

5-2. Acrylic adhesive polymer (B)
The acrylic adhesive polymer (B) disclosed herein is a polymer containing (meth)acrylic acid esters as a main structural unit. Examples of the acrylic adhesive polymer (B) include acrylic random copolymers and acrylic block copolymers.

<About acrylic random copolymer>
When the acrylic adhesive polymer (B) is a random copolymer, the acrylic adhesive polymer (B) has adhesiveness whose glass transition temperature (Tg) is, for example, in the range of -80°C or higher and 10°C or lower. It is a polymer with The lower limit of Tg may be -70°C or higher, -60°C or higher, -50°C or higher, or -40°C or higher. The upper limit of Tg may be 0°C or less, -10°C or less, -20°C or less, or -30°C or less. Further, the range of Tg can be a combination of these upper and lower limits as appropriate, but for example, it is preferably in the range of -70°C or more and 0°C or less, and for example, it is -60°C or more and -10°C or less, For example, the temperature is -50°C or more and -20°C or less. Note that when Tg is −80° C. or higher, a pressure-sensitive adhesive having sufficient cohesive force and good adhesiveness can be obtained. Moreover, if Tg is 10° C. or less, good step followability can be provided. The Tg of the acrylic adhesive polymer (B) is a value measured by DSC at a temperature increase rate of 10° C./min.

Furthermore, the weight average molecular weight (Mw) of the acrylic adhesive polymer (B) is preferably 100,000 or more from the viewpoint of exhibiting sufficient cohesive force and good adhesiveness. The lower limit of Mw may be 300,000 or more, 400,000 or more, or 500,000 or more. Further, it is preferable that the Mw is 400,000 or more because the heat resistance is further improved. On the other hand, if Mw is too large, the level difference followability tends to decrease, and handling in manufacturing may become difficult. Therefore, the upper limit of Mw is preferably 5,000,000 or less. The upper limit value of Mw may be 3,000,000 or less, 2,000,000 or less, or 1,000,000 or less.

The number average molecular weight (Mn) of the acrylic adhesive polymer (B) is preferably 30,000 or more from the viewpoint of exhibiting sufficient cohesive force and good adhesiveness. The lower limit of Mn may be 40,000 or more, 50,000 or more, or 60,000 or more. The upper limit value of Mn is preferably 3,000,000 or less in order to ensure good step followability. The upper limit value of Mn may be 1,000,000 or less, or may be 800,000 or less.

Further, the ratio (Mw/Mn) between weight average molecular weight (Mw) and number average molecular weight (Mn) is, for example, 6.0 or less from the viewpoint of easily obtaining good adhesive strength. Mw/Mn may be 5.0 or less, 4.7 or less, 4.5 or less, 4.0 or less, 3.8 or less. It may be 3.6 or less. Note that the weight average molecular weight Mw and the number average molecular weight Mn are standard polystyrene equivalent values obtained using gel permeation chromatography (GPC).

As monomers constituting the acrylic adhesive polymer (B), alkyl (meth)acrylates having an alkyl group having 1 to 12 carbon atoms are used, since an acrylic copolymer having good adhesiveness can be obtained. Examples include esters and (meth)acrylic acid alkoxyalkyl esters having an alkoxyalkyl group having 2 to 12 carbon atoms. As the monomers constituting the acrylic adhesive polymer (B), one or more of these can be used.

Examples of the (meth)acrylic acid alkyl ester having an alkyl group having 1 to 12 carbon atoms include methyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate, and n-(meth)acrylate. Butyl, isobutyl (meth)acrylate, n-hexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-(meth)acrylate Nonyl, isononyl (meth)acrylate, n-decyl (meth)acrylate, lauryl (meth)acrylate, etc., and preferred monomers include n-butyl (meth)acrylate, (meth)acrylate 2 -ethylhexyl, n-octyl (meth)acrylate, isooctyl (meth)acrylate, n-nonyl (meth)acrylate, isononyl (meth)acrylate, and the like.

Examples of the (meth)acrylic acid alkoxyalkyl ester having an alkoxyalkyl group having 2 to 12 carbon atoms include methoxymethyl (meth)acrylate, ethoxymethyl (meth)acrylate, butoxymethyl (meth)acrylate, and ) Methoxyethyl acrylate, ethoxyethyl (meth)acrylate, butoxyethyl (meth)acrylate, methoxybutyl (meth)acrylate, ethoxybutyl (meth)acrylate, butoxybutyl (meth)acrylate, and the like.

The amount of the (meth)acrylic acid alkyl ester having an alkyl group having 1 to 12 carbon atoms and/or the (meth)acrylic acid alkoxyalkyl ester having an alkoxyalkyl group having 2 to 12 carbon atoms to be used is not particularly limited. However, since good adhesive performance tends to be obtained, the lower limit can be 10% by mass or more, and 20% by mass or more, based on the total constituent monomers of the acrylic copolymer. The content may be 30% by mass or more, 40% by mass or more, or 50% by mass or more. Further, the upper limit thereof is 100% by mass or less, may be 99% by mass, may be 95% by mass or less, may be 90% by mass or less, and may be 80% by mass or less. Good too. The range of the usage amount can be set by appropriately combining these upper and lower limits, but for example, 10% by mass or more and 100% by mass or less, 10% by mass or more and 99% by mass or less, 20% by mass or more and 95% by mass or less, Further, for example, the content may be 30% by mass or more and 90% by mass or less. If it is 10% by mass or more, it is preferable in that a pressure-sensitive adhesive composition having good adhesive strength, initial adhesive strength (tack), low-temperature tackiness, etc. can be obtained.

Among the above, (meth)acrylic acid alkyl esters having an alkyl group having 1 to 3 carbon atoms can be used. By using such a (meth)acrylic acid alkyl ester, it is possible to improve the Tg of the acrylic adhesive polymer (B) and the elastic modulus of the adhesive layer described below, which is advantageous for improving the heat resistance of the adhesive layer. . Preferably, an alkyl (meth)acrylate having an alkyl group having 1 to 2 carbon atoms, more preferably methyl (meth)acrylate.

In addition to the above-mentioned (meth)acrylic acid alkyl ester and (meth)acrylic acid alkoxyalkyl ester, the acrylic adhesive polymer (B) may contain other monomers that can be copolymerized with these to the extent that the adhesiveness is not impaired. body can be used.

Examples of other vinyl monomers include α,β-ethylenically unsaturated carboxylic acid monomers such as (meth)acrylic acid, itaconic acid, maleic acid, and fumaric acid; styrene, α-methylstyrene, and vinyl Aromatic vinyl monomers such as toluene; cyclohexyl (meth)acrylate, methylcyclohexyl (meth)acrylate, tert-butylcyclohexyl (meth)acrylate, cyclododecyl (meth)acrylate, isobornyl (meth)acrylate aliphatic cyclic vinyl monomers such as; monoalkyl esters of unsaturated dicarboxylic acids such as monoethyl itaconate and monobutyl fumarate; 2-hydroxyethyl (meth)acrylate, 3-(meth)acrylate Hydroxyl group-containing vinyl monomers such as hydroxypropyl, 4-hydroxybutyl (meth)acrylate, polyethylene glycol (meth)acrylate, polypropylene glycol (meth)acrylate, and polyethylene-polypropylene glycol mono(meth)acrylate; acrylamide, N-methylol Ethylenically unsaturated carboxylic acid amides and N-substituted compounds such as acrylamide, N-methoxymethylacrylamide, N-methoxybutylacrylamide; Unsaturated alcohols such as allyl alcohol; (meth)acrylonitrile, vinyl acetate, glycidyl (meth)acrylate , diacetone acrylamide, etc., and one or more of these can be used.

When an α,β-ethylenically unsaturated carboxylic acid monomer is used, the resulting pressure-sensitive adhesive composition is preferred from the viewpoint of increasing adhesive strength to adherends such as glass, metal, and ABS plates. When using an α,β-ethylenically unsaturated carboxylic acid monomer, the amount of α,β-ethylenically unsaturated carboxylic acid monomer to be used is based on the total constituent monomers of the acrylic copolymer. , preferably 1% by mass or more and 20% by mass or less, more preferably 2% by mass or more and 15% by mass or less, still more preferably 3% by mass or more and 10% by mass or less. If the amount used is 1% by mass or more, the effect of improving the adhesive force to the adherend can be obtained, and if the amount used is 20% by mass or less, good adhesiveness is maintained. One type or two or more types of α,β-ethylenically unsaturated carboxylic acid monomers may be used. From the viewpoint of polymerizability, (meth)acrylic acid is preferred.

In addition, a polyfunctional polymerizable monomer having two or more polymerizable functional groups such as a (meth)acryloyl group or an alkenyl group in the molecule may be used. The polyfunctional polymerizable monomer also acts as a so-called crosslinking agent, and by using it, a crosslinked structure can be formed in the adhesive polymer.

Examples of polyfunctional (meth)acrylate compounds include ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, polyethylene glycol di(meth)acrylate, and polypropylene glycol di(meth)acrylate. Di(meth)acrylates of dihydric alcohols such as meth)acrylate; trimethylolpropane tri(meth)acrylate, tri(meth)acrylate modified with trimethylolpropane ethylene oxide, glycerin tri(meth)acrylate, pentaerythritol tri( Examples include poly(meth)acrylates such as tri(meth)acrylates of trihydric or higher polyhydric alcohols such as meth)acrylates and pentaerythritol tetra(meth)acrylates, and tetra(meth)acrylates.

Examples of polyfunctional alkenyl compounds include polyfunctional allyl ether compounds such as trimethylolpropane diallyl ether, pentaerythritol diallyl ether, pentaerythritol triallyl ether, tetraallyloxyethane, and polyallyl sucrose; polyfunctional allyl compounds such as diallyl phthalate; methylene Examples include bisamides such as bisacrylamide and hydroxyethylenebisacrylamide; polyfunctional vinyl compounds such as divinylbenzene, and the like.

Compounds having both a (meth)acryloyl group and an alkenyl group include allyl (meth)acrylate, isopropenyl (meth)acrylate, butenyl (meth)acrylate, pentenyl (meth)acrylate, and (meth)acrylic acid. Examples include 2-(2-vinyloxyethoxy)ethyl.

The acrylic adhesive polymer (B) can also be obtained by known radical polymerization methods such as solution polymerization, suspension polymerization, and emulsion polymerization. Furthermore, a commercially available product may be used as the acrylic adhesive polymer (B). Examples of such commercial products include SK Dyne 2950, 2953, and 2943H manufactured by Soken Kagaku Co., Ltd., and Coponil 8711 and N-2411TF manufactured by Nippon Gosei Kagaku Co., Ltd.

In addition, the acrylic adhesive polymer (B) can also be obtained from an acrylic adhesive polymer syrup. In this case, the acrylic adhesive polymer syrup contains a polymer component that is a part of the acrylic adhesive polymer (B) and a (meth)acrylic monomer that constitutes the remainder of the acrylic adhesive polymer (B). can do. The acrylic adhesive polymer (B) is obtained by applying energy such as heat or active energy rays to the acrylic adhesive polymer syrup and polymerizing the monomer components contained in the syrup.

<About acrylic block copolymer>
When the acrylic adhesive polymer (B) is an acrylic block copolymer (hereinafter referred to as "this block copolymer"), the present block copolymer is composed of polymer block (a) and (meth)acrylic It is preferable that each of them has one or more polymer blocks (b). This block copolymer is, for example, an (ab) diblock consisting of a polymer block (a) and a (meth)acrylic polymer block (b), a polymer block (a)/(meth)acrylic polymer (aba) triblock consisting of block (b)/polymer block (a), or (meth)acrylic polymer block (b)/polymer block (a)/(meth)acrylic polymer block (b) ) and the like (bab) triblock. Moreover, it may have a structure such as (abc) or (abca) containing a polymer block (c) other than the polymer block (a) and the (meth)acrylic polymer block (b). Among these, the present block copolymer preferably has an a-(ba)n (n is an integer of 1 or more) structure. With such a structure, the polymer block (a) forms a pseudo-crosslinked structure, which is suitable from the viewpoint of adhesive properties. The above a-(ba)n structure may be present in all or part of the copolymer, and for example, a copolymer having a (babab) structure may be used.
Here, regarding the glass transition point of this block copolymer, the inflection point corresponding to each polymer block can be obtained by performing differential scanning calorimetry, and the Tg of each polymer block can be determined from these. can. In the present disclosure, the Tg of the present block copolymer means the Tg of the main component polymer block (more specifically, the acrylic polymer block (b)).

(Polymer block (a))
The polymer block (a) of the present block copolymer can be a block having a structural unit derived from at least one monomer selected from the group consisting of maleimide compounds and amide group-containing vinyl compounds.

（式中、Ｒ^１は水素、炭素数１～３のアルキル基又はＰｈＲ^２を表す。ただし、Ｐｈはフェニル基を表し、Ｒ^２は水素、ヒドロキシ基、炭素数１～２のアルコキシ基、アセチル基又はハロゲンを表す。）Maleimide compounds include maleimide and N-substituted maleimide compounds. Examples of the N-substituted maleimide compound include N-methylmaleimide, N-ethylmaleimide, Nn-propylmaleimide, N-isopropylmaleimide, Nn-butylmaleimide, N-isobutylmaleimide, N-tert-butylmaleimide. , N-alkyl-substituted maleimide compounds such as N-pentylmaleimide, N-hexylmaleimide, N-heptylmaleimide, N-octylmaleimide, N-laurylmaleimide, N-stearylmaleimide; N-cyclopentylmaleimide, N-cyclohexylmaleimide, etc. N-cycloalkyl substituted maleimide compound; N-phenylmaleimide, N-(4-hydroxyphenyl)maleimide, N-(4-acetylphenyl)maleimide, N-(4-methoxyphenyl)maleimide, N-(4-ethoxyphenyl) ) Maleimide, N-(4-chlorophenyl)maleimide, N-(4-bromophenyl)maleimide, N-benzylmaleimide, and other N-aryl- or N-aralkyl-substituted maleimide compounds, and one of these or Two or more types can be used. By polymerizing a monomer containing a maleimide compound, a structural unit derived from the maleimide compound can be introduced into the polymer block (a). In the polymer block (a), among the above compounds, the compound represented by the following general formula (1) is preferable because the resulting block copolymer has better heat resistance and adhesiveness.

(In the formula, R ¹ represents hydrogen, an alkyl group having 1 to 3 carbon atoms, or PhR ^2. However, Ph represents a phenyl group, and R ² represents hydrogen, a hydroxy group, an alkoxy group having 1 to 2 carbon atoms, or an acetyl group. (represents a group or halogen)

Examples of amide group-containing vinyl compounds include (meth)acrylamide, tert-butyl (meth)acrylamide, N,N-dimethyl (meth)acrylamide, N,N-diethyl (meth)acrylamide, and N-isopropyl (meth)acrylamide. , N,N-dimethylaminopropyl (meth)acrylamide, (meth)acrylamide derivatives such as (meth)acryloylmorpholine; N-vinylamide monomers such as N-vinylacetamide, N-vinylformamide, N-vinylisobutyramide, etc. etc., and one or more types of these can be used. By polymerizing a monomer containing an amide group-containing vinyl compound, a structural unit derived from the amide group-containing vinyl compound can be introduced into the polymer block (a).

In the polymer block (a), the structural unit derived from at least one selected from the group consisting of a maleimide compound and an amide group-containing vinyl compound is 10% by mass based on the total structural units of the polymer block (a). The content can be 100% by mass or less. Such structural units are, for example, 15% by mass or more, for example 20% by mass or more, for example 30% by mass or more, for example 40% by mass or more, and for example 50% by mass or more, and For example, it is 60% by mass or more. The amount of structural units derived from at least one selected from the group consisting of maleimide compounds and amide group-containing vinyl compounds is, for example, 99% by mass or less, for example, 90% by mass or less, and for example, 80% by mass or less. , for example, 75% by mass or less, and for example, 70% by mass or less. If the structural unit derived from at least one selected from the group consisting of maleimide compounds and amide group-containing vinyl compounds is less than 10% by mass, the resulting block copolymer will not have sufficient heat resistance, durability, and peeling resistance. There are times.

The polymer block (a) may further include a structural unit derived from an aromatic vinyl monomer. Aromatic vinyl monomers include styrene and its derivatives. Specific compounds include, for example, styrene, α-methylstyrene, β-methylstyrene, vinylxylene, vinylnaphthalene, o-methylstyrene, m-methylstyrene, p-methylstyrene, o-ethylstyrene, m-ethyl Styrene, p-ethylstyrene, p-n-butylstyrene, p-isobutylstyrene, p-t-butylstyrene, o-methoxystyrene, m-methoxystyrene, p-methoxystyrene, o-chloromethylstyrene, p-chloro Examples include methylstyrene, o-chlorostyrene, p-chlorostyrene, o-hydroxystyrene, m-hydroxystyrene, p-hydroxystyrene, divinylbenzene, etc., and one or more of these can be used. . By polymerizing a monomer containing an aromatic vinyl monomer, a structural unit derived from the aromatic vinyl monomer can be introduced into the polymer block (a).

Among the above, from the viewpoint of polymerizability, the aromatic vinyl monomers constituting the polymer block (a) are styrene, o-methoxystyrene, m-methoxystyrene, p-methoxystyrene, o-hydroxystyrene. , m-hydroxystyrene, and p-hydroxystyrene are preferred. Further, α-methylstyrene, β-methylstyrene, and vinylnaphthalene are preferable because they can increase the glass transition point (Tg) of the polymer block (a) and provide a block with excellent heat resistance.

In the polymer block (a), the structural unit derived from the aromatic vinyl monomer can be 1% by mass or more and 70% by mass or less with respect to all the structural units of the polymer block (a). The content of such structural units is, for example, 5% by mass or more, further, for example, 10% by mass or more, and further, for example, 20% by mass or more. The structural unit derived from the aromatic vinyl monomer is, for example, 60% by mass or less, further, for example, 50% by mass or less, and, for example, 40% by mass or less. If the structural unit derived from the aromatic vinyl monomer is 1% by mass or more, the polymerizability of the maleimide compound can be particularly improved. On the other hand, if it is 70% by mass or less, it is possible to secure the necessary amount of structural units derived from maleimide compounds and/or amide group-containing vinyl compounds, so it is possible to create blocks with excellent heat resistance, durability, and peeling resistance. Polymers can be obtained.

Moreover, the polymer block (a) may be a block containing a structural unit derived from a vinyl monomer having a crosslinkable functional group (hereinafter also referred to as a "crosslinkable structural unit"). The crosslinkable structural unit may be introduced using, for example, a maleimide compound and/or an amide group-containing vinyl compound having a functional group such as a hydroxy group, or by copolymerizing a vinyl compound having a crosslinkable functional group. May be introduced.

The vinyl monomer having a crosslinkable functional group is not particularly limited, and various known monomer compounds can be used. Examples of vinyl monomers having a crosslinkable functional group include α,β-ethylenically unsaturated carboxylic acid monomers, unsaturated acid anhydride monomers, hydroxyl group-containing vinyl monomers, and epoxy group-containing vinyl monomers. Monomers, primary or secondary amino group-containing vinyl monomers, reactive silicon group-containing vinyl monomers, and the like. In the production of the polymer block (a), the vinyl monomer having a crosslinkable functional group can be used singly or in combination of two or more of known compounds.

Examples of the α,β-ethylenically unsaturated carboxylic acid monomer include (meth)acrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, citraconic acid, and cinnamic acid. These compounds may be used alone or in combination of two or more. Examples of the unsaturated acid anhydride monomer include maleic anhydride, itaconic anhydride, citraconic anhydride, and the like. These compounds may be used alone or in combination of two or more. Examples of the hydroxyl group-containing vinyl monomer include the hydroxyl group-containing vinyl monomers exemplified as other monomers of the acrylic adhesive polymer (B).

Examples of the epoxy group-containing vinyl monomer include glycidyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate glycidyl ether, and 3,4-epoxycyclohexylmethyl (meth)acrylate. These compounds may be used alone or in combination of two or more.

Examples of vinyl monomers containing primary or secondary amino groups include aminoethyl (meth)acrylate, aminopropyl (meth)acrylate, N-methylaminoethyl (meth)acrylate, N-ethylaminoethyl (meth)acrylate, etc. Amino group-containing (meth)acrylic acid ester; ) acrylamide, etc.

Examples of the reactive silicon group-containing vinyl monomer include vinyl silanes such as vinyltrimethoxysilane, vinyltriethoxysilane, vinylmethyldimethoxysilane, and vinyldimethylmethoxysilane; trimethoxysilylpropyl (meth)acrylate, (meth)acrylate; Silyl group-containing (meth)acrylic acid esters such as triethoxysilylpropyl acrylate, methyldimethoxysilylpropyl (meth)acrylate, and dimethylmethoxysilylpropyl (meth)acrylate; silyl group-containing vinyl ethers such as trimethoxysilylpropyl vinyl ether silyl group-containing vinyl esters such as vinyl trimethoxysilyl undecanoate. These compounds may be used alone or in combination of two or more. Reactive silicon group-containing vinyl monomers are preferred because they can easily incorporate two or more crosslinkable functional groups. Further, in such a vinyl monomer, reactive silicon groups can undergo dehydration condensation (polymerization) with each other. Therefore, it is suitable in that the polymerization reaction for producing the block copolymer and the subsequent crosslinking reaction can be efficiently carried out.

In addition to the above, by copolymerizing an oxazoline group-containing vinyl monomer and/or an isocyanate group-containing vinyl monomer, an oxazoline group and/or an isocyanate group can be added to the polymer block (a) as a crosslinkable functional group. can be introduced.

Furthermore, by copolymerizing a polyfunctional polymerizable monomer having two or more polymerizable unsaturated groups in the molecule, a polymerizable unsaturated group is introduced as a crosslinkable functional group into the polymer block (a). obtain. The above-mentioned polyfunctional polymerizable monomer is a compound having two or more polymerizable functional groups such as a (meth)acryloyl group or an alkenyl group in the molecule, and includes a polyfunctional (meth)acrylate compound, a polyfunctional alkenyl compound, Examples include compounds having both a (meth)acryloyl group and an alkenyl group. For example, in addition to alkylene diol diacrylates such as hexanediol diacrylate, allyl (meth)acrylate, isopropenyl (meth)acrylate, butenyl (meth)acrylate, pentenyl (meth)acrylate, and di(meth)acrylate. Examples include compounds having both a (meth)acryloyl group and an alkenyl group in the molecule, such as -(2-vinyloxyethoxy)ethyl. These compounds may be used alone or in combination of two or more.

When the polymer block (a) has a crosslinkable structural unit, for example, the crosslinkable structural unit can be included in an amount of 0.01% by mass or more based on all the structural units of the polymer block (a). Further, the content of the crosslinkable structural unit is, for example, 0.1% by mass or more, for example, 1.0% by mass or more, and, for example, 2.0% by mass or more. By including 0.01% by mass or more of the crosslinkable structural unit, it becomes easier to obtain a good crosslinked structure, and it becomes easier to obtain a block copolymer having high heat resistance and durability. Note that the upper limit of the content of the crosslinkable structural unit is not particularly limited, but from the viewpoint of controllability of the crosslinking reaction, it is, for example, 60% by mass or less, for example, 40% by mass or less, and, for example, 20% by mass. % or less, and for example, 10% by mass or less. The range of the content of the crosslinkable structural unit can be appropriately combined with the above-mentioned lower limit and upper limit, but for example, 1% by mass or more and 60% by mass or less, and for example 5% by mass or more and 50% by mass or less, 10% by mass. It can be more than 40% by mass or less.

The polymer block (a) can also include structural units derived from other monomers copolymerizable with these monomers, within a range that does not impair the effects of the block copolymer. The other monomers can include, for example, (meth)acrylic acid alkyl esters, (meth)acrylic acid alkoxyalkyl esters, aliphatic cyclic vinyl monomers of (meth)acrylic acid, and the like. These compounds may be used alone or in combination of two or more. Specific examples of (meth)acrylic acid alkyl esters, (meth)acrylic acid alkoxyalkyl esters, and aliphatic cyclic vinyl monomers include (meth)acrylic acid that can be used in the production of acrylic adhesive polymer (B). Examples include acid alkyl esters, (meth)acrylic acid alkoxyalkyl esters, and aliphatic cyclic vinyl monomers.

Other monomers other than those mentioned above include N,N-dimethylaminoethyl (meth)acrylate, N,N-diethylaminoethyl (meth)acrylate, and N,N-dimethylaminopropyl (meth)acrylate.
In the polymer block (a), the proportion occupied by the structural units derived from the other monomers mentioned above is, for example, in the range of 0% by mass or more and 50% by mass or less based on the total structural units of the polymer block (a). It can be done. Further, the proportion of the structural units derived from the other monomers mentioned above is, for example, 5% by mass or more, and for example, 10% by mass or more. Further, the proportion of the structural units derived from the other monomers mentioned above is, for example, 45% by mass or less, and for example, 40% by mass or less.

(Glass-transition temperature)
The glass transition temperature (Tg) of the polymer block (a) is preferably 100°C or higher. The Tg of the polymer block (a) can contribute to the heat resistance of the block copolymer. Therefore, it is preferable that the Tg is 100° C. or higher because good heat resistance can be imparted to the block copolymer. Furthermore, the Tg of the polymer block (a) is, for example, 120°C or higher, for example 140°C or higher, for example 160°C or higher, for example 180°C or higher, or for example 190°C or higher. , and for example, 200°C or higher. Further, Tg is preferably 350° C. or lower due to limitations on usable constituent monomer units. Further, Tg is, for example, 280°C or lower, for example 270°C or lower, or, for example, 260°C or lower.

In addition, in this specification, the glass transition point of the block copolymer in addition to the polymer block (a) and the (meth)acrylic polymer block (b) is determined by differential scanning calorimetry as described in the Examples below. (DSC). Furthermore, when DSC is not possible, it can be determined by calculation from the monomer units constituting the polymer block.

(phase separation)
It is preferable that the polymer block (a) has the property of phase-separating from the (meth)acrylic polymer block (b). By having such properties, a microphase-separated structure can be formed. A person skilled in the art can easily design a block that phase separates from the (meth)acrylic polymer block (b) based on the common general knowledge at the time of filing this application. For example, when the SP value of the polymer block (a) calculated by a known solubility parameter calculation method, for example, the Fedors method shown below, is compared with the SP value of the (meth)acrylic polymer block (b), The difference may be 0.01 (absolute value) or more. Further, the difference may be, for example, 0.05 or more, for example, 0.1 or more, or, for example, 0.2 or more. Furthermore, it may be, for example, 0.5 or more. Alternatively, for example, a polymer blend of the intended polymer block (a) and (meth)acrylic polymer block (b) is prepared, and the structure obtained by mixing these is examined using an electron microscope, an atomic force microscope, or a small-angle X-ray microscope. Phase separation between blocks can be easily estimated by observing with line scattering or the like.

（ただし、数式（２）中、δ、ΔＥｖａｐ及びＶは以下のとおりである。
δ ：ＳＰ値（（ｃａｌ／ｃｍ^３）^１／２）
ΔＥｖａｐ ：各原子団のモル蒸発熱（ｃａｌ／ｍｏｌ）
Ｖ ：各原子団のモル体積（ｃｍ^３／ｍｏｌ））The SP value is R. F. It can be calculated by the calculation method described in "Polymer Engineering and Science" 14(2), 147 (1974) written by John Fedors. Specifically, the calculation method shown in equation (2) is used.

(However, in formula (2), δ, ΔEvap, and V are as follows.
δ: SP value ((cal/cm ³ ) ^1/2 )
ΔEvap: Molar heat of vaporization of each atomic group (cal/mol)
V: molar volume of each atomic group (cm ³ /mol))

((meth)acrylic polymer block (b))
The (meth)acrylic polymer block (b) of this block copolymer is a polymer block having a structural unit derived from a (meth)acrylic monomer, and is represented by the following general formula (3). A block having at least one constituent unit selected from the following compounds can be used. Examples of the compound represented by general formula (3) include (meth)acrylic acid alkyl ester, (meth)acrylic acid alkoxyalkyl ester, polyalkylene glycol mono(meth)acrylate, and the like.
CH ₂ =CR ³ -C(=O)O-(R ⁴ O) _n -R ⁵ (3)
(In formula (3), R ³ represents hydrogen or a methyl group, R ⁴ represents a linear or branched alkylene group having 2 to 6 carbon atoms, and R ⁵ represents hydrogen or an alkyl group having 1 to 20 carbon atoms. or represents an aryl group having 6 to 20 carbon atoms. n represents 0 or an integer of 1 to 100.)

The (meth)acrylic acid alkyl ester and (meth)acrylic acid alkoxyalkyl ester can be used for producing the acrylic adhesive polymer (B). can be mentioned.

The polyalkylene glycol mono(meth)acrylate may contain only one type of (R ⁴ O) in the above general formula (3), or may contain two or more types of structural units. When there are two or more types of (R ⁴ O), n represents the total number of repeating units of each structural unit. n may be 1 to 100, 1 to 50, or 1 to 30. Specific compounds include polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, polyethylene glycol-polypropylene glycol mono(meth)acrylate, polyethylene glycol-polytetraethylene glycol mono(meth)acrylate, and methoxypolyethylene glycol. Mono(meth)acrylate, lauroxypolyethylene glycol mono(meth)acrylate, stearoxypolyethylene glycol mono(meth)acrylate, octoxypolyethylene glycol-polypropylene glycol mono(meth)acrylate, phenoxypolyethylene glycol mono(meth)acrylate, phenoxypolyethylene Examples include glycol-polypropylene glycol mono(meth)acrylate, nonylphenoxypolyethylene glycol mono(meth)acrylate, nonylphenoxypolypropylene glycol mono(meth)acrylate, nonylphenoxypolyethylene glycol-polypropylene glycol mono(meth)acrylate, and the like. The above-mentioned compounds are also available as commercial products, and examples of methoxypolyethylene glycol monomethacrylate include "Blemmer PME series" (n=2, 4, 9, 23, 90, etc., Blemmer is a registered trademark). In addition, (meth)acrylic acid ester compounds having functional groups such as amide groups, amino groups, carboxy groups, and hydroxy groups can also be used.

Among the above, the (meth)acrylic polymer block (b) is an alkyl group having 1 to 12 carbon atoms or an alkoxyalkyl group having 2 to 8 carbon atoms, since a block copolymer with excellent flexibility can be obtained. It is preferable to have a structural unit derived from an acrylic acid alkyl ester compound having a group. In addition, when considering the adhesive performance, the (meth)acrylic polymer block (b) is an acrylic acid alkyl ester compound having an alkyl group having 1 to 8 carbon atoms or an alkoxyalkyl group having 2 to 3 carbon atoms. It is more preferable that it contains a structural unit derived from.

In the (meth)acrylic polymer block (b), the structural units derived from the compound represented by the general formula (3) are added to all the structural units of the (meth)acrylic polymer block (b). It can be 20% by mass or more and 100% by mass or less. Such structural units are, for example, 50% by mass or more and 100% by mass or less, for example 80% by mass or more and 100% by mass or less, and for example 90% by mass or more and 100% by mass or less. When the above structural unit is within the above range, a block copolymer with good adhesive properties tends to be obtained. In addition, when the above-mentioned structural unit is 50% by mass or more, the (meth)acrylic polymer block (b) contains at least one type of compound represented by the general formula (3) as the main constituent monomer. It becomes a block.

Moreover, the (meth)acrylic polymer block (b) can be a block containing a crosslinkable structural unit. The crosslinkable structural unit can be introduced, for example, by copolymerizing a vinyl compound having a crosslinkable functional group.

When the (meth)acrylic polymer block (b) has a crosslinkable structural unit, for example, the crosslinkable structural unit is 0.01% by mass based on the total structural units of the (meth)acrylic polymer block (b). The above may be provided. Further, the content of the crosslinkable structural unit is, for example, 0.1% by mass or more, and for example, 0.5% by mass or more. When the amount of crosslinkable structural units introduced is 0.01% by mass or more, it becomes easier to obtain a block copolymer with excellent heat resistance. The upper limit of the content of the crosslinkable structural unit is not particularly limited, but from the viewpoint of flexibility, it is, for example, 20% by mass or less, for example, 10% by mass or less, and, for example, 8% by mass or less. be. The range of the crosslinkable structural unit can be appropriately combined with the above-mentioned lower and upper limits. The content may be 5% by mass or more and 8% by mass or less.

The (meth)acrylic polymer block (b) may contain monomers other than the above-mentioned (meth)acrylic monomers as constituent monomer units, as long as this does not impede the effects achieved by the present disclosure. Can be done. As the monomer other than the (meth)acrylic monomer, a monomer having an unsaturated group other than the (meth)acryloyl group can be used. Specific examples thereof include aliphatic or aromatic vinyl compounds such as alkyl vinyl esters, alkyl vinyl ethers, and styrenes.

(Glass-transition temperature)
The glass transition temperature (Tg) of the (meth)acrylic polymer block (b) is preferably 10°C or lower. The Tg of the (meth)acrylic polymer block (b) can contribute to the tackiness of the block copolymer. Therefore, when Tg is 10°C or less, better adhesiveness can be imparted to the block copolymer. Further, the Tg of the (meth)acrylic polymer block (b) is, for example, 0°C or lower, for example, -5°C or lower, for example, -10°C or lower, or, for example, -20°C or lower. , and, for example, -25°C or lower, and, for example, -30°C or lower. The lower limit of Tg of the (meth)acrylic polymer block (b) is, for example, −80° C. or higher.

(phase separation)
As mentioned above, the (meth)acrylic polymer block (b) preferably has the property of phase separation from the polymer block (a), and has a predetermined difference from the SP value of the polymer block (a). It is preferable to have

This block copolymer is not subject to any particular restrictions as long as a block copolymer having a polymer block (a) and a (meth)acrylic polymer block (b) is obtained, and a known production method is adopted. can do. Examples include methods that utilize various controlled polymerization methods such as living radical polymerization and living anionic polymerization, and methods that couple polymers having functional groups. Among these, the living radical polymerization method is preferred because it is easy to operate and can be applied to a wide range of monomers.

There are no particular restrictions on the type of living radical polymerization, and examples include reversible addition-fragmentation chain transfer polymerization (RAFT), nitroxy radical polymerization (NMP), atom transfer radical polymerization (ATRP), and organic tellurium compounds. Various polymerization methods can be employed, such as a polymerization method using an organic antimony compound (TERP method), a polymerization method using an organic antimony compound (SBRP method), a polymerization method using an organic bismuth compound (BIRP method), and an iodine transfer polymerization method. Among these, the RAFT method, NMP method and ATRP method are preferred from the viewpoint of polymerization controllability and ease of implementation.

In the RAFT method, controlled polymerization proceeds via a reversible chain transfer reaction in the presence of a specific polymerization control agent (RAFT agent) and a general free radical polymerization initiator. As the RAFT agent, various known RAFT agents such as dithioester compounds, xanthate compounds, trithiocarbonate compounds, and dithiocarbamate compounds can be used. As the RAFT agent, a monofunctional agent having only one active site may be used, or a bifunctional or more functional agent may be used. It is preferable to use a bifunctional RAFT agent in that it is easy to efficiently obtain the block copolymer having the a-(ba)n type structure. Further, the amount of the RAFT agent used is appropriately adjusted depending on the monomer used, the type of RAFT agent, etc.

As the polymerization initiator used in polymerization by the RAFT method, known radical polymerization initiators such as azo compounds, organic peroxides, and persulfates can be used. Azo compounds are preferred because they are less likely to cause a reaction. Specific examples of azo compounds include those mentioned above. The above radical polymerization initiators may be used alone or in combination of two or more.

The usage ratio of the radical polymerization initiator is not particularly limited, but from the viewpoint of obtaining a polymer with a smaller molecular weight distribution, it is preferable that the usage amount of the radical polymerization initiator is 0.5 parts by mass or less with respect to 1 part by mass of the RAFT agent. , more preferably 0.3 parts by mass or less. Further, from the viewpoint of stably performing the polymerization reaction, the lower limit of the amount of the radical polymerization initiator to be used per 1 part by mass of the RAFT agent is preferably 0.01 part by mass or more. Therefore, the amount of the radical polymerization initiator used per 1 part by mass of the RAFT agent is preferably in the range of 0.01 to 0.5 parts by mass, more preferably in the range of 0.05 to 0.3 parts by mass.

The reaction temperature during the polymerization reaction by the RAFT method is preferably 40°C or higher and 100°C or lower, more preferably 45°C or higher and 90°C or lower, and still more preferably 50°C or higher and 80°C or lower. When the reaction temperature is 40° C. or higher, the polymerization reaction can proceed smoothly. On the other hand, if the reaction temperature is 100° C. or lower, side reactions can be suppressed and restrictions regarding usable initiators and solvents are relaxed.

（式（４）中、Ｒ^６は炭素数１～２のアルキル基又は水素原子であり、Ｒ^７は炭素数１～２のアルキル基又はニトリル基であり、Ｒ^８は－（ＣＨ_２）ｍ－、ｍは０～２であり、Ｒ^９、Ｒ^１０は炭素数１～４のアルキル基である。）In the NMP method, a specific alkoxyamine compound having nitroxide or the like is used as a living radical polymerization initiator, and polymerization proceeds via nitroxide radicals derived therefrom. In the production of the block copolymer used in the present invention, there are no particular limitations on the type of nitroxide radical used, and commercially available nitroxide polymerization initiators can be used. Further, from the viewpoint of polymerization controllability when polymerizing a monomer containing an acrylate, it is preferable to use a compound represented by general formula (4) as the nitroxide compound.

(In formula (4), R ⁶ is an alkyl group having 1 to 2 carbon atoms or a hydrogen atom, R ⁷ is an alkyl group having 1 to 2 carbon atoms or a nitrile group, and R ⁸ is -(CH ₂ )m -, m are 0 to 2, and R ⁹ and R ¹⁰ are alkyl groups having 1 to 4 carbon atoms.)

The nitroxide compound represented by the above general formula (4) undergoes primary dissociation by heating to about 70 to 80°C and causes an addition reaction with the vinyl monomer. At this time, it is possible to obtain a polyfunctional polymerization precursor by adding a nitroxide compound to a vinyl monomer having two or more vinyl groups. Next, the vinyl monomer can be subjected to living polymerization by subjecting the polymerization precursor to secondary dissociation under heating. In this case, since the polymerization precursor has two or more active sites in the molecule, a polymer with a narrower molecular weight distribution can be obtained. From the viewpoint of easily obtaining the block copolymer having the above a-(ba)n type structure, it is preferable to use a bifunctional polymerization precursor having two active sites in the molecule. Further, the amount of the nitroxide compound to be used is appropriately adjusted depending on the type of monomer and nitroxide compound used.

（式（５）中、Ｒ^１１、Ｒ^１２は炭素数１～４のアルキル基である。）When producing this block copolymer by the NMP method, 0.001 to 0.2 mol of the nitroxide radical represented by the following general formula (5) is added to 1 mol of the nitroxide compound represented by the above general formula (4). Polymerization may be carried out by adding within a certain range.

(In formula (5), R ¹¹ and R ¹² are alkyl groups having 1 to 4 carbon atoms.)

By adding 0.001 mol or more of the nitroxide radical represented by the above general formula (5), the time required for the concentration of the nitroxide radical to reach a steady state is shortened. This makes it possible to control polymerization to a higher degree and to obtain a polymer with a narrower molecular weight distribution. On the other hand, if the amount of the nitroxide radical added is too large, polymerization may not proceed. A more preferable amount of the nitroxide radical added is in the range of 0.01 to 0.5 mol, and a still more preferable amount is in the range of 0.05 to 0.2 mol per mol of the nitroxide compound.

The reaction temperature in the NMP method is preferably 50°C or more and 140°C or less, more preferably 60°C or more and 130°C or less, even more preferably 70°C or more and 120°C or less, particularly preferably 80°C or more and 120°C. It is as follows. When the reaction temperature is 50° C. or higher, the polymerization reaction can proceed smoothly. On the other hand, if the reaction temperature is 140° C. or lower, side reactions such as radical chain transfer tend to be suppressed.

In the ATRP method, a polymerization reaction is generally performed using an organic halide as an initiator and a transition metal complex as a catalyst. The organic halide used as the initiator may be monofunctional, or may be difunctional or more functional. It is preferable to use a difunctional compound because it is easy to efficiently obtain the block copolymer having the a-(ba)n type structure. Further, as the type of halogen, bromide and chloride are preferable. The reaction temperature in the ATRP method is preferably 20°C or more and 200°C or less, more preferably 50°C or more and 150°C or less. If the reaction temperature is 20° C. or higher, the polymerization reaction can proceed smoothly.

By a living radical polymerization method, a-(ba)n such as an (aba) triblock copolymer consisting of a polymer block (a)-(meth)acrylic polymer block (b)-polymer block (a) When obtaining a mold structure, for example, the desired block copolymer may be obtained by sequentially polymerizing each block. In this case, first, as a first polymerization step, a polymer block (a) is obtained using constituent monomers of the polymer block (a). Next, in a second polymerization step, a (meth)acrylic polymer block (b) is obtained using the constituent monomers of the (meth)acrylic polymer block (b). Furthermore, as a third polymerization step, a triblock copolymer (aba) can be obtained by polymerizing using the constituent monomers of the polymer block (a). In this case, it is preferable to use the monofunctional polymerization initiator or polymerization precursor described above as the polymerization initiator. By repeating the above-mentioned second polymerization step and third polymerization step, a higher order block copolymer such as a pentablock copolymer can be obtained.

Furthermore, it is preferable to produce the product by a method including the two-stage polymerization process described below, since the desired product can be obtained more efficiently. That is, as a first polymerization step, after obtaining a (meth)acrylic polymer block (b) using the constituent monomers of the (meth)acrylic polymer block (b), as a second polymerization step, The constituent monomers of the combined block (a) are polymerized to obtain the polymer block (a). As a result, a (aba) triblock copolymer consisting of a polymer block (a)-(meth)acrylic polymer block (b)-polymer block (a) can be obtained. In this case, it is preferable to use a bifunctional polymerization initiator or a polymerization precursor as the polymerization initiator. According to this method, the process can be simplified compared to the case where each block is manufactured by sequentially polymerizing each block. Further, by repeating the first polymerization step and the second polymerization step described above, a higher order block copolymer such as a tetra block copolymer can be obtained.

Polymerization of the block copolymer used in the present invention may be carried out in the presence of a chain transfer agent, if necessary, regardless of the polymerization method. Known chain transfer agents can be used, and specifically, ethanethiol, 1-propanethiol, 2-propanethiol, 1-butanethiol, 2-butanethiol, 1-hexanethiol, 2-hexane. Thiol, 2-methylheptane-2-thiol, 2-butylbutane-1-thiol, 1,1-dimethyl-1-pentanethiol, 1-octanethiol, 2-octanethiol, 1-decanethiol, 3-decanethiol, 1-undecanethiol, 1-dodecanethiol, 2-dodecanethiol, 1-tridecanethiol, 1-tetradecanethiol, 3-methyl-3-undecanethiol, 5-ethyl-5-decanethiol, tert-tetradecanethiol, 1 - In addition to alkylthiol compounds having an alkyl group having 2 to 20 carbon atoms such as hexadecanethiol, 1-heptadecanethiol and 1-octadecanethiol, mercaptoacetic acid, mercaptopropionic acid, 2-mercaptoethanol, etc. One or more of these can be used.

In producing the block copolymer used in the present disclosure, polymerization solvents known in living radical polymerization can be used. Specifically, aromatic compounds such as benzene, toluene, xylene, and anisole; ester compounds such as methyl acetate, ethyl acetate, propyl acetate, and butyl acetate; ketone compounds such as acetone and methyl ethyl ketone; dimethylformamide, acetonitrile, dimethyl sulfoxide, Examples include alcohol and water. Alternatively, the polymerization may be carried out in a manner such as bulk polymerization without using a polymerization solvent.

5-3. Preferred embodiment of the present adhesive layer When the thin film layer of the present adhesive sheet is thin film layer 1, the present adhesive composition preferably contains an acrylic adhesive polymer (B), and a vinyl polymer (A). and acrylic adhesive polymer (B). When the thin film layer of the present adhesive sheet is thin film layer 2, the present adhesive composition preferably contains a vinyl polymer (A) and an acrylic adhesive polymer (B). When the present adhesive composition contains a vinyl polymer (A) and an acrylic adhesive polymer (B), the vinyl polymer (A) has appropriate compatibility with the acrylic adhesive polymer (B). It is preferable to have. In this case, the adhesive layer obtained from the adhesive composition containing the vinyl polymer (A) and the acrylic adhesive polymer (B) exhibits good transparency, and the adhesive layer contains the vinyl polymer (A). ) may be partially segregated, and the concentration of vinyl polymer (A) in the surface layer may be higher than in other parts.

In this way, if the surface layer of the adhesive layer has a higher concentration of vinyl polymer (A) than the other layers, the adhesive layer near the adhesive interface will have a relatively high Tg, so it will work well even under high temperature conditions. It can exhibit excellent adhesive properties. Furthermore, since the adhesive layer as a whole has a low Tg and is sufficiently flexible, when applied to a decorative film, it can follow the thermal expansion and contraction of the film base material and suppress stress in an appropriate manner. can be relaxed. Thereby, when the present decorative film is adhered to an adherend by vacuum-pressure forming, the effect of suppressing the generation of shock lines in the decorative film can be increased. In addition to this segregation behavior of the vinyl polymer (A) in the present adhesive composition, the difference in Tg between the surface layer of the adhesive layer and the entire adhesive layer, which will be described later, is due to the difference in Tg between the vinyl polymer (A) and the acrylic adhesive polymer (B). It can be adjusted by appropriately setting the blending ratio of A), the monomer composition (polarity) and molecular weight of the vinyl polymer (A), as well as Tg, Mw/Mn, etc.

When the present adhesive composition contains the vinyl polymer (A), the present adhesive composition contains the vinyl polymer (A) per 100 parts by mass of the acrylic adhesive polymer (B) in terms of solid content. The content is preferably 0.5 parts by mass or more and 60 parts by mass or less. The lower limit of the preferable content is 1 part by mass or more, more preferably 3 parts by mass or more, and still more preferably 4 parts by mass or more. Further, the upper limit of the content is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, and even more preferably 30 parts by mass or less. Further, the preferred content range is 1 part by mass or more and 40 parts by mass or less, more preferably 3 parts by mass or more and 30 parts by mass or less. If the amount of the vinyl polymer (A) used is less than 0.5 parts by mass, the segregation of the vinyl polymer (A) in the adhesive layer will be insufficient, and satisfactory results, especially in high temperature adhesion, will not be obtained. There is. On the other hand, if it exceeds 60 parts by mass, the vinyl polymer (A) may segregate excessively, resulting in insufficient level followability and adhesiveness including tackiness. In addition, it may phase separate from the acrylic adhesive polymer (B) and the transparency of the adhesive layer may decrease.

[Tg of the entire adhesive layer formed from the present adhesive composition (first Tg)]
The glass transition temperature (Tg) of the entire adhesive layer formed from the present adhesive composition (hereinafter also referred to as "this adhesive layer"), that is, the first Tg, is -80°C or more and 20°C or less. It can be a range. The lower limit of Tg may be -70°C or higher, -60°C or higher, -50°C or higher, or -40°C or higher. Further, the upper limit of the first Tg may be 15°C or less, 10°C or less, 0°C or less, -10°C or less, -20°C or less. It may be the following. Further, the range of the first Tg can be a combination of these upper and lower limits as appropriate, and is, for example, in the range of -70°C or more and 30°C or less, or -60°C or more and 20°C or less, and For example, the temperature is -50°C or more and -10°C or less. If the first Tg is less than -80°C, the cohesive force of the resulting pressure-sensitive adhesive layer will be insufficient, and curved surface adhesion etc. will tend to deteriorate. If the first Tg exceeds 20° C., the step followability and adhesive strength under low temperature conditions may not be sufficient. Note that the Tg of the entire adhesive layer can be obtained by DSC at a temperature increase rate of 10° C./min and a nitrogen atmosphere as the measurement atmosphere.

[Tg calculated from the composition of the surface layer portion of the adhesive layer (second Tg)]
When the thin film layer of the present pressure-sensitive adhesive sheet is thin film layer 2, the second Tg, that is, when the pressure-sensitive adhesive layer is obtained by drying or irradiation with active energy rays after coating the present pressure-sensitive adhesive composition on a separator, The Tg calculated from the composition of the surface layer portion of the adhesive layer obtained by X-ray photoelectron spectroscopy is 70° C. or higher. Specifically, the second Tg is calculated from the composition ratio of the vinyl polymer (A) and the acrylic adhesive polymer (B) obtained from X-ray photoelectron spectroscopy (XPS). It can be regarded as the Tg of the composition forming the surface layer from the surface of the layer to a depth of about 20 nm. That is, in XPS, photoelectrons generated by irradiating the surface of the adhesive layer with X-rays are detected, and composition information can be obtained from the kinetic energy of the photoelectrons, and the detection depth is generally several nm. Therefore, by XPS, it is possible to obtain composition information regarding the surface layer portion of about several nm from the surface of the adhesive layer, and this can be taken as the Tg of the thin film layer 2. The details of the measurement method can follow the operations described in the Examples below.

When the thin film layer of the adhesive sheet is thin film layer 2, the second Tg is 70°C or higher, so that it does not develop adhesiveness at room temperature and has good handling properties when preforming. In addition, it is possible to suppress the occurrence of shock lines when applied to vacuum pressure forming. In addition, by setting the second Tg to 70°C or higher, it becomes easy to sufficiently increase the difference between the first Tg and the second Tg, and as a result, it is possible to improve not only the curved surface adhesion but also the high temperature adhesion of the adherend. Durability can be ensured. The second Tg is more preferably 75°C or higher, still more preferably 80°C or higher, still more preferably 85°C or higher. Note that the second Tg can be adjusted as appropriate by adjusting the Tg of the vinyl polymer (A), the blending ratio, and the like. The upper limit of the second Tg is, for example, 180° C. or lower, although it is not particularly limited.

When the thin film layer of the adhesive sheet is thin film layer 1, the second Tg is not particularly limited, but is preferably 0° C. or higher. The second Tg is more preferably 10°C or higher, still more preferably 30°C or higher, still more preferably 40°C or higher, even more preferably 50°C or higher, even more preferably 60°C or higher. be.

[Difference between Tg of the entire adhesive layer (first Tg) and Tg calculated from the composition of the surface layer portion of the adhesive layer (second Tg)]
This adhesive composition has a second Tg (Tg calculated from the composition of the surface layer of the adhesive layer) that is 30°C or more higher than the first Tg (Tg of the entire adhesive layer). is preferred. An adhesive layer having such a Tg composition has high adhesion at high temperatures (peelability to adherends), whereas adhesive layers using conventional general adhesives exhibit lower adhesion as the temperature increases. strength) and high curved surface adhesion. Furthermore, if the second Tg is 30°C or more higher than the first Tg, the decorative film with the adhesive layer formed from the present adhesive composition may have complex surfaces such as curved surfaces or uneven parts. It follows the shape and shows good adhesion. Further, even if the film base material shrinks under high-temperature conditions, for example, appearance defects such as shifting, peeling, or lifting are suppressed, and excellent durability is exhibited.

The second Tg is higher than the first Tg by preferably 40°C or more, more preferably 50°C or more, still more preferably 60°C or more, still more preferably 65°C or more, and even more preferably 70°C or more. More preferred. The upper limit of the height of the second Tg relative to the first Tg is not particularly limited, but the upper limit is 280°C from the values that the first Tg and the second Tg can take, and generally 200°C. It is as follows.

[Mass fraction (A/A+B) of vinyl polymer (A) relative to the total mass of vinyl polymer (A) and acrylic adhesive polymer (B) in the surface layer portion of the adhesive layer]
When measuring the second Tg, the composition of the surface layer of the adhesive layer is analyzed by X-ray photoelectron spectroscopy, and at that time, the mass fraction of the vinyl polymer (A) in the surface layer can be determined. This mass fraction can be used as an index of the segregation state of the vinyl polymer (A) in the surface layer portion of the adhesive layer.

For example, the mass fraction of the vinyl polymer (A) in the surface layer portion of the adhesive layer is preferably 55% or more and 95% or less. Within this range, segregation of the vinyl polymer (A) to the surface layer portion occurs, and curved surface adhesion and durability can be obtained even under high temperature and high humidity conditions. The mass fraction of the vinyl polymer (A) is more preferably 60% or more, still more preferably 65% or more, still more preferably 70% or more, still more preferably 75% or more, and even more preferably Preferably it is 80% or more. Further, the mass fraction is preferably 95% or less, more preferably 90% or less.

[Transparency (haze value)]
The haze value can be used as an index for evaluating the transparency of the adhesive layer obtained from the present adhesive composition. The adhesive layer obtained from this adhesive composition exhibits good transparency. Further, in an embodiment in which the adhesive composition includes a vinyl polymer (A) and an acrylic adhesive polymer (B), the vinyl polymer (A) has appropriate compatibility with the acrylic adhesive polymer (B). When the adhesive layer contains these, the adhesive layer exhibits good transparency.

The haze value can be evaluated, for example, by the following method. That is, after peeling off one separator pasted on the adhesive sheet, transferring the adhesive sheet onto a glass plate, and peeling off the other separator, it was left to stand at 23°C and 50% RH for one day, and the haze was removed. Measure the haze value using a meter. It can be evaluated that the lower the haze value, the better the transparency. A preferred haze value is 2.0 or less. When the haze value is 2.0 or less, it can be said that there is a certain desirable transparency. A more preferable haze value is 1.6 or less, still more preferably 1.4 or less, and still more preferably 1.0 or less.

5-4. Other Components In a preferred embodiment of the adhesive composition, in addition to the vinyl polymer (A) and the acrylic adhesive polymer (B), optionally a crosslinking agent, a tackifier, a plasticizer, and an antioxidant are added. The composition may also contain additives such as ultraviolet absorbers, anti-aging agents, flame retardants, fungicides, silane coupling agents, fillers, and colorants.

[Crosslinking agent]
This adhesive composition can contain a crosslinking agent. Although a crosslinking agent is not necessarily required, its addition is considered depending on the intended adhesive properties as well as the form of the pressure-sensitive adhesive composition, for example, whether it is in an emulsion form or a solution form. By containing a crosslinking agent, the cohesive force and adhesive force of the adhesive layer obtained from this adhesive composition can be adjusted, and furthermore, it can provide adhesiveness under high temperature and high humidity conditions and adhesiveness to curved surfaces. be able to. As a crosslinking agent, an epoxy compound having two or more epoxy groups, an isocyanate compound having two or more isocyanate groups, an aziridine compound having two or more aziridinyl groups, an oxazoline compound having an oxazoline group, a metal chelate compound, a butylated melamine compound etc. Among these, it is preferable to use aziridine compounds, epoxy compounds and isocyanate compounds.

Examples of the aziridine compound include 1,6-bis(1-aziridinylcarbonylamino)hexane, 1,1'-(methylene-di-p-phenylene)bis-3,3-aziridylurea, 1,1' -(hexamethylene)bis-3,3-aziridylurea, ethylenebis-(2-aziridinylpropionate), tris(1-aziridinyl)phosphine oxide, 2,4,6-triaziridinyl-1,3,5 -triazine, trimethylolpropane-tris-(2-aziridinylpropionate), and the like.

Examples of the epoxy compound include bisphenol A epichlorohydrin type epoxy resin, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, glycerin diglycidyl ether, and neopentyl glycol diglycidyl ether. Ether, 1,6-hexanediol diglycidyl ether, diglycidylaniline, tetraglycidylxylylenediamine, N,N ,N',N'-tetraglycidyl-m-xylylenediamine, 1,3-bis(N,N- Examples include polyfunctional glycidyl compounds such as diglycidylaminomethyl) cyclohexane, trimethylolpropane polyglycidyl ether, diglycerol polyglycidyl ether, polyglycerol polyglycidyl ether, and sorbitol polyglycidyl ether.

As the isocyanate compound, preferably a compound having two or more isocyanate groups is used. As the above-mentioned isocyanate compound, various aromatic, aliphatic, and alicyclic isocyanate compounds, and modified products (prepolymers, etc.) of these isocyanate compounds can be used.

Examples of aromatic isocyanates include diphenylmethane diisocyanate (MDI), crude diphenylmethane diisocyanate, tolylene diisocyanate, naphthalene diisocyanate (NDI), p-phenylene diisocyanate (PPDI), xylylene diisocyanate (XDI), and tetramethylxylylene diisocyanate (TMXDI). , tolidine diisocyanate (TODI), and the like. Examples of the aliphatic isocyanate include hexamethylene diisocyanate (HDI), lysine diisocyanate (LDI), lysine triisocyanate (LTI), and the like. Examples of the alicyclic isocyanate include isophorone diisocyanate (IPDI), cyclohexyl diisocyanate (CHDI), hydrogenated XDI (H6XDI), hydrogenated MDI (H12MDI), and the like. Examples of modified isocyanates include urethane-modified products, dimers, trimers, carbodiimide-modified products, allophanate-modified products, biuret-modified products, urea-modified products, isocyanurate-modified products, oxazolidone-modified products, and isocyanates of the above-mentioned isocyanate compounds. Examples include group-terminated prepolymers.

The content of the crosslinking agent can be preferably 0.01 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the acrylic adhesive polymer (B). The lower limit is more preferably 0.03 parts by mass or more, and even more preferably 0.05 parts by mass or more. Further, the upper limit is more preferably 5 parts by mass or less, and even more preferably 2 parts by mass or less. Further, a more preferable range is 0.03 parts by weight or more and 5 parts by weight or less, and an even more preferable range is 0.05 parts by weight or more and 2 parts by weight or less.

[Tackifier]
Tackifiers mainly include rosin derivatives such as rosin ester, gum rosin, tall oil rosin, hydrogenated rosin ester, maleated rosin, and disproportionated rosin ester; terpene phenol resin, α-pinene, β-pinene, limonene, etc. Examples include terpene resins; (hydrogenated) petroleum resins; coumaron-indene resins; hydrogenated aromatic copolymers; styrene resins; phenolic resins; xylene resins; (meth)acrylic polymers.

[Plasticizer]
Examples of plasticizers include phthalic acid esters such as di-n-butyl phthalate, di-n-octyl phthalate, bis(2-ethylhexyl) phthalate, di-n-decyl phthalate, and diisodecyl phthalate; bis(2-ethylhexyl) adipate, di-n - Adipate esters such as octyl adipate; Sebacate esters such as bis(2-ethylhexyl) sebacate and di-n-butyl sebacate; Azelaic acid esters such as bis(2-ethylhexyl) azelate; Paraffins such as chlorinated paraffin Glycols such as polypropylene glycol; Epoxy-modified vegetable oils such as epoxidized soybean oil and epoxidized linseed oil; Phosphate esters such as trioctyl phosphate and triphenyl phosphate; Phosphite esters such as triphenyl phosphite; Ester oligomers such as esters of adipic acid and 1,3-butylene glycol; low molecular weight polymers such as low molecular weight polybutene, low molecular weight polyisobutylene, and low molecular weight polyisoprene; oils such as process oils and naphthenic oils, etc. can be mentioned.

〔Antioxidant〕
As antioxidants, 2,6-di-tert-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-tert-butyl-4-ethylphenol, stearyl-β-(3,5-di -tert-butyl-4-hydroxyphenyl) propionate, 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 2,2'-methylenebis(4-ethyl-6-tert-butylphenol), 4, 4'-thiobis(3-methyl-6-tert-butylphenol), 4,4'-butylidenebis(3-methyl-6-tert-butylphenol), 3,9-bis[1,1-dimethyl-2-[β -(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]ethyl]2,4,8,10-tetraoxaspiro[5.5]undecane, 1,3-tris(2-methyl- 4-hydroxy-5-tert-butylphenyl)butane, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, tetrakis-[methylene -3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate]methane, bis[3,3'-bis-(4'-hydroxy-3'-tert-butylphenyl)butyl ric acid] glycol ester, 1,3,5-tris(3',5'-di-tert-butyl-4'-hydroxybenzyl)-S-triazine-2,4,6-(1H,3H,5H) Phenolic antioxidants such as trione and tocopherols; sulfur-based antioxidants such as dilauryl 3,3'-thiodipropionate, dimyristyl 3,3'-thiodipropionate, and stearyl 3,3'-thiodipropionate Agent; triphenyl phosphite, diphenylisodecyl phosphite, 4,4'-butylidene-bis(3-methyl-6-tert-butylphenylditridecyl) phosphite, cyclic neopentanetetrylbis(octadecyl phosphite) , tris(nonylphenyl) phosphite, tris(monononylphenyl) phosphite, tris(dinonylphenyl) phosphite, diisodecylpentaerythritol diphosphite, 9,10-dihydro-9-oxa-10-phosphaphenanthrene- 10-oxide, 10-(3,5-di-tert-butyl-4-hydroxybenzyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-decyloxy-9,10 -dihydro-9-oxa-10-phosphaphenanthrene, tris(2,4-di-tert-butylphenyl) phosphite, cyclic neopentanetetrayl bis(2,4-di-tert-butylphenyl) phosphite , cyclic neopentanetetrayl bis(2,6-di-tert-butyl-4-methylphenyl) phosphite, 2,2-methylenebis(4,6-di-tert-butylphenyl)octyl phosphite, etc. Examples include antioxidants.

[Ultraviolet absorber]
Examples of UV absorbers include salicylic acid UV absorbers such as phenyl salicylate, p-tert-butylphenyl salicylate, and p-octylphenyl salicylate; 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, and 2-hydroxy- 4-Octoxybenzophenone, 2-hydroxy-4-dodecyloxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2-hydroxy-4-methoxy Benzophenone UV absorbers such as -5-sulfobenzophenone and bis(2-methoxy-4-hydroxy-5-benzoylphenyl)methane; 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-( 2'-Hydroxy-5'-tert-butylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)benzotriazole, 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole,2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole, 2-(2 '-hydroxy-3',5'-di-tert-amylphenyl)benzotriazole, 2-(2'-hydroxy-4'-octoxyphenyl)benzotriazole, 2-[2'-hydroxy-3'-( 3",4",5",6"-tetrahydrophthalimidomethyl)-5'-methylphenyl]benzotriazole, 2,2-methylenebis[4-(1,1,3,3-tetramethylbutyl)-6- (2H-benzotriazol-2-yl)phenol], 2-(2'-hydroxy-5'-methacryloxyphenyl)-2H-benzotriazole, 2,2'-methylenebis[4-(1,1,3, Benzotriazole UV absorbers such as 3-tetramethylbutyl)-6-(2H-benzotriazol-2-yl)phenol; 2-ethylhexyl-2-cyano-3,3'-diphenylacrylate, ethyl-2- Cyanoacrylate UV absorbers such as cyano-3,3'-diphenylacrylate; nickel bis(octylphenyl) sulfide, [2,2'-thiobis(4-tert-octylphenolate)]-n-butylamine nickel, nickel Examples include nickel-based ultraviolet stabilizers such as complex-3,5-di-tert-butyl-4-hydroxybenzyl-phosphate monoethylate and nickel-dibutyldithiocarbamate.

[Anti-aging agent]
As anti-aging agents, poly(2,2,4-trimethyl-1,2-dihydroquinoline), 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline, 1-(N-phenylamino )-naphthalene, styrenated diphenylamine, dialkyldiphenylamine, N,N'-diphenyl-p-phenylenediamine, N-phenyl-N'-isopropyl-p-phenylenediamine, N,N'-di-2-naphthyl-p- Phenylendiamine, 2,6-di-tert-butyl-4-methylphenol, mono(α-methylbenzyl)phenol, di(α-methylbenzyl)phenol, tri(α-methylbenzyl)phenol, 2,2'- Methylenebis(4-methyl-6-tert-butylphenol), 2,2'-methylenebis(4-ethyl-6-tert-butylphenol), 4,4'-butylidenebis(6-tert-butyl-3-methylphenol), 4,4'-thiobis(6-tert-butyl-3-methylphenol), 1,1-bis(4-hydroxyphenyl)cyclohexane, 2,5-di-tert-butylhydroquinone, 2,5-di-tert -Amylhydroquinone, 2-mercaptobenzimidazole, zinc salt of 2-mercaptobenzimidazole, 2-mercaptomethylbenzimidazole, nickel dibutyldithiocarbamate, tris(nonylphenyl)phosphite, dilauryl thiodipropionate, dithiodipropionate Examples include stearyl.

〔Flame retardants〕
Flame retardants include tetrabromobisphenol A, 2,2-bis(4-hydroxy-3,5-dibromophenyl)propane, hexabromobenzene, tris(2,3-dibromopropyl)isocyanurate, 2,2-bis (4-hydroxyethoxy-3,5-dibromophenyl)propane, decabromodiphenyl oxide, halogen-based flame retardants such as halogen-containing polyphosphate; ammonium phosphate, tricresyl phosphate, triethyl phosphate, tris(β-chloroethyl) Phosphorous flame retardants such as phosphate, trischloroethyl phosphate, trisdichloropropyl phosphate, cresyl diphenyl phosphate, xylenyl diphenyl phosphate, acidic phosphoric acid ester, nitrogen-containing phosphorus compounds; red phosphorus, tin oxide, antimony trioxide, water Inorganic flame retardants such as zirconium oxide, barium metaborate, aluminum hydroxide, magnesium hydroxide; poly(dimethoxysiloxane), poly(diethoxysiloxane), poly(diphenoxysiloxane), poly(methoxyphenoxysiloxane), methyl silicate , ethyl silicate, phenyl silicate, and other siloxane flame retardants.

[Fungicide]
Examples of fungicides include benzimidazole, benzothiazole, trihaloallyl, triazole, organic nitrogen sulfur compounds, and the like.
〔Silane coupling agent〕
Examples of the silane coupling agent include vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-glycidoxysilane. Propyltriethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-chloropropylmethoxysilane, vinyltrichlorosilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β (Aminoethyl)-γ-aminopropyltrimethoxysilane and the like.
〔filler〕
Examples of the filler include inorganic powder fillers such as calcium carbonate, titanium oxide, mica, and talc; fibrous fillers such as glass fiber and organic reinforcing fiber.

5-5． Form of the present pressure-sensitive adhesive composition There are no particular restrictions on the form of the present pressure-sensitive adhesive composition. For example, it may be used in the form of a solvent-type adhesive composition dissolved in an organic solvent such as ethyl acetate, or in the form of an emulsion-type adhesive composition in which an acrylic adhesive polymer and a tackifier are dispersed in an aqueous medium. It may also be used as In the case of solution-type adhesive compositions and emulsion-type adhesive compositions, the amount of the medium such as the organic solvent or water used is usually 20 to 95 parts by weight out of 100 parts by weight of the total amount of the adhesive composition.

When used as an emulsion type adhesive, a stabilizer may be added. Stabilizers for vinyl chloride include cadmium stearate, zinc stearate, barium stearate, calcium stearate, lead dibutyltin dilaurate, tris(nonylphenyl) phosphite, triphenyl phosphite, diphenylisodecyl phosphite, etc. Stabilizer; di-n-octyltin bis(isooctylthioglycolic acid ester) salt, di-n-octyltin maleate polymer, di-n-octyltin dilaurate, di-n-octyltin maleic acid Ester salt, di-n-butyltin bismaleate salt, di-n-butyltin maleate polymer, di-n-butyltin bisoctylthioglycol ester salt, di-n-butyltin β-mercaptopropionate polymer, di-n-butyltin bisoctylthioglycol ester salt, -n-butyltin dilaurate, di-n-methyltin bis(isooctylmercaptoacetate) salt, poly(thiobis-n-butyltin sulfide), monooctyltin tris(isooctylthioglycolic acid ester), dibutyltin maleate, di-n- Organotin stabilizers such as butyl tin maleate ester/carboxylate and di-n-butyl tin maleate ester/mercaptide; tribasic lead sulfate, dibasic lead phosphite, basic lead sulfite, dibasic phthalate Lead stabilizers such as acid lead, lead silicate, dibasic lead stearate, lead stearate; metals such as cadmium soap, zinc soap, barium soap, lead soap, composite metal soap, calcium stearate, etc. Examples include soap stabilizers.

In addition to the vinyl polymer (A) and the acrylic adhesive polymer (B), the adhesive composition also contains monofunctional and/or polyfunctional (meth)acrylic acid monomers, and By forming the composition to include a photopolymerization initiator and the like, it may be used in the form of a so-called syrup-type photocurable adhesive composition that is cured by active energy rays such as ultraviolet rays.

In the case of a photocurable pressure-sensitive adhesive composition, the composition may contain an organic solvent or the like, but is generally used as a solvent-free type that does not contain any solvents.

Examples of monofunctional (meth)acrylic acid monomers include (meth)acrylic acid alkyl esters having an alkyl group having 1 to 12 carbon atoms; cyclohexyl (meth)acrylate, dicyclopentyl (meth)acrylate, and ) (meth)acrylic acid esters having a cyclic structure such as isobornyl acrylate; hydroxyalkyl (meth)acrylates such as hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, and hydroxybutyl (meth)acrylate; Esters; (meth)acrylic acid and the like. These compounds may be used alone or in combination of two or more.

Polyfunctional (meth)acrylic acid monomers include alkylene glycol di(meth)acrylates such as butanediol di(meth)acrylate and hexanediol di(meth)acrylate; triethylene glycol di(meth)acrylate Di(meth)acrylates of polyalkylene glycols such as trimethylolpropane tri(meth)acrylate and its modified products with ethylene oxide and/or propylene oxide, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, etc. Can be mentioned. In addition, polymers (macromonomers) having (meth)acryloyl groups such as polyurethane (meth)acrylate and polyisoprene (meth)acrylate can also be used. Specific examples of polyisoprene-based (meth)acrylates include, for example, esterified products of maleic anhydride adducts of isoprene polymers and 2-hydroxyethyl methacrylate. These compounds may be used alone or in combination of two or more.

Examples of the photopolymerization initiator include benzoin and its alkyl ethers, acetophenones, anthraquinones, thioxanthones, ketals, benzophenones, xanthones, acylphosphine oxides, α-diketones, and the like. Moreover, in order to improve the sensitivity to active energy rays, a photosensitizer can also be used in combination. Examples of the photosensitizer include benzoic acid-based and amine-based photosensitizers. These can also be used in combination of two or more types. The amount of the photoinitiator and photosensitizer used is preferably 0.01 to 10 parts by weight per 100 parts by weight of the monofunctional and/or polyfunctional (meth)acrylic acid monomer.

Furthermore, in addition to the photocurable adhesive composition described above, the present adhesive composition also includes the vinyl polymer (A), monofunctional and/or polyfunctional (meth)acrylic acid monomer, It can also be used as a photocurable adhesive composition containing a photopolymerization initiator. The above-mentioned acrylic adhesive polymer (B) can be mixed into the photocurable adhesive composition, if necessary.

Specific examples that embody the disclosure of this specification will be shown below. However, the disclosure of this specification is not limited to the following specific examples. In the following description, "part" means part by mass, and "%" means % by mass.

Various analyzes herein were carried out by the methods described below.
<Solid content>
Approximately 1 g of the measurement sample was weighed (a), and then the residue after drying in a ventilation dryer at 155° C. for 30 minutes was measured (b), and calculated from the following formula. A weighing bottle was used for the measurement. Other operations were conducted in accordance with JIS K 0067-1992 (methods for weight loss and residue testing of chemical products).
Solid content (%) = (b/a) x 100

<Molecular weight measurement>
The molecular weight was measured by GPC under the following conditions.
GPC: Tosoh (HLC-8120)
Column: Tosoh (TSKgel-Super MP-M x 4)
Sample concentration: 0.1%
Flow rate: 0.6ml/min Eluent: Tetrahydrofuran Column temperature: 40°C
Detector: Differential refractometer (RI)
Standard material: polystyrene

<Glass transition temperature (Tg) and melting point>
The Tg and melting point of the entire adhesive layer formed from the polyolefin resin, vinyl polymer (A), acrylic adhesive polymer (B), and adhesive composition were determined by DSC under the following conditions in accordance with JIS K7121. It was measured with
DSC: Manufactured by TA Instrument (Q-100)
Heating temperature: 10℃/min Measurement atmosphere: Nitrogen <softening point>
The softening points of polyolefin resins and polyester resins were measured by the ring and ball method in accordance with JIS K6863. When the thin film layer was made of rosin ester resin, it was measured by the ring and ball method in accordance with JIS5902.

<Polymer composition>
The polymer composition was calculated from the amount of monomer charged and the amount of monomer consumption measured by gas chromatography (GC).
GC: Manufactured by Agilent Technologies (7820A GC System)
Detector: FID
Column: 100% dimethylsiloxane (CP-Sil 5CB) length 30m, inner diameter 0.32mm
Calculation method: Internal standard method

1. Synthesis of vinyl polymer (A) [Synthesis example 1: Synthesis of polymer A-1]
In a four-neck flask with an internal volume of 1 liter, butyl acetate (200 parts by mass) and dimethyl-2,2'-azobis(2-methylpropionate) (manufactured by Wako Pure Chemical Industries, Ltd., product name "V-") were added. 601'') (0.9 parts by mass) was charged, the mixed liquid was sufficiently degassed by bubbling nitrogen gas, and the internal temperature of the mixed liquid was raised to 90°C. Separately, methyl methacrylate (hereinafter referred to as "MMA") (165 parts by mass), isobornyl methacrylate (hereinafter referred to as "IBXMA") (44 parts by mass), V-601 (17 parts by mass), butyl acetate (90 parts by mass) Polymerization was carried out by dropping a mixed solution consisting of the following parts) from a dropping funnel into a flask over a period of 5 hours. After completion of the dropping, the vinyl polymer in the polymerization solution was isolated by dropping the polymerization solution into a mixed solution consisting of methanol (4800 parts by mass) and distilled water (1200 parts by mass) to obtain polymer A-1. Ta. The polymer composition of the obtained polymer A-1 was calculated from the amount charged and the amount of monomer consumed by GC measurement, and was found to be 80% by mass of MMA and 20% by mass of IBXMA. Polymer A-1 had Mw of 6,700, Mn of 4,370, Mw/Mn of 1.53, and Tg of 108°C.

2. Synthesis of acrylic adhesive polymer (B) [Synthesis example 2: Synthesis of polymer B-1]
In a 4-neck flask with an internal volume of 3 liters, methoxyethyl acrylate (hereinafter referred to as "MEA") (413 parts by mass), 2-hydroxyethyl acrylate (hereinafter referred to as "HEA") (27 parts by mass), and acrylic. n-Butyl acid (hereinafter referred to as "BA") (90 parts by mass) and ethyl acetate (980 parts by mass) were charged, and this mixed solution was sufficiently degassed by bubbling nitrogen gas to bring the internal temperature of the mixed solution to 75%. ℃, charged with 2,2'-azobis(2,4-dimethylvaleronitrile) (manufactured by Wako Pure Chemical Industries, Ltd., trade name "V-65") (0.25 parts by mass), and heated for 5 hours. Polymerized. Ethyl acetate was added so that the solid content concentration was 30% to obtain an ethyl acetate solution of Polymer B-1. The polymer composition of the obtained polymer B-1 was 78% by mass of MEA, 5% by mass of HEA, and 17 parts by mass of BA. Polymer B-1 had an Mw of 572,000, an Mn of 160,000, an Mw/Mn of 3.58, and a Tg of -35°C.

[Synthesis Example 3: Synthesis of Polymer B-2]
In a four-necked flask with an internal volume of 3 liters, acrylic acid (hereinafter referred to as "AA") (30 parts by mass), BA (210 parts by mass), and methyl acrylate (hereinafter referred to as "MA") (360 parts by mass). , ethyl acetate (1000 parts by mass) was charged, this mixture was sufficiently degassed by bubbling nitrogen gas, the internal temperature of the mixture was raised to 75°C, and V-65 (0.30 parts by mass) was charged. , polymerized for 5 hours. Ethyl acetate was added so that the solid content concentration was 30% to obtain an ethyl acetate solution of Polymer B-2. The polymer composition of the obtained polymer B-2 was 5% by mass of AA, 35% by mass of BA, and 60 parts by mass of MA. Polymer B-2 had an Mw of 529,000, an Mn of 142,000, an Mw/Mn of 3.73, and a Tg of 6°C.

[Synthesis Example 4: Synthesis of Polymer B-3]
In a four-necked flask with an internal volume of 1 L, dibenzyl trithiocarbonate (3.18 parts by mass) as a RAFT agent, styrene (75 parts by mass, hereinafter referred to as "St") as a monomer, and N-phenylmaleimide ( (125 parts by mass, hereinafter referred to as "PhMI") and acetonitrile (466 parts by mass) as a solvent were charged, and the mixture was sufficiently degassed by nitrogen bubbling, and the internal temperature of the mixture was raised to 70°C. Next, 2,2'-azobis(2-methylbutyronitrile) (0.51 parts by mass, hereinafter referred to as "ABN-E") was charged as a polymerization initiator to initiate polymerization. After 3 hours, the reaction was stopped by cooling to room temperature. The polymer block (a) was obtained by purifying the above polymerization solution by reprecipitation from methanol and vacuum drying. The obtained polymer block (a) had an Mn of 10,900. Tg was 206°C.
In a four-necked flask with an internal volume of 1 L, the obtained polymer block (a) (21.1 parts by mass), monomers MEA (234 parts by mass), BA (51 parts by mass), and HEA (15 parts by mass) were placed. parts) and acetonitrile (107 parts by mass) as a solvent were charged, and the mixture was sufficiently degassed by nitrogen bubbling, and the internal temperature of the mixture was raised to 70°C. Next, ABN-E (0.08 parts by mass) was added as a polymerization initiator to start polymerization. After 6 hours, the mixture was cooled to room temperature and the solid content concentration was adjusted to 30% by adding acetonitrile to obtain an adhesive solution. The obtained (a)-(b)-(a) block copolymer (this will be referred to as "Polymer B-3") contains 3% by mass of PhMI, 2% by mass of St, 74% by mass of MEA, 16% by mass of BA, and 5% by mass of HEA. Mw was 358,000, Mn was 16,0000, Mw/Mn was 2.24, and Tg was -35°C. Table 1 shows the composition and analysis results of Polymer B-3.

3. Manufacture and evaluation of adhesive sheets
Example 1
(1) Coating of thin film layer 1 Acid-modified polyolefin resin C-1 (Toyotac PMA-T manufactured by Toyobo Co., Ltd.) was dissolved in toluene to prepare a solution with a solid content concentration of 5% by mass. This solution was applied onto a polyethylene terephthalate (hereinafter referred to as "PET") separator having a thickness of 50 μm using a doctor blade so that the thickness after drying would be several μm. The coating film was dried at 80° C. for 1 minute.

(2) Preparation and coating of adhesive composition Takenate D-110N (Mitsui Chemicals, Inc.) was added as a crosslinking agent to a solution (solid content concentration 30%) containing the polymer B-1 obtained in Synthesis Example 2 above. A pressure-sensitive adhesive composition 1 was obtained by mixing an isocyanate-based crosslinking agent (solid content concentration: 75% by mass) (0.16 parts by mass).

(3) Manufacture of adhesive sheet Adhesive composition 1 was applied onto the PET separator with thin film prepared in (1) above using a doctor blade so that the thickness of the adhesive layer after drying was 50 μm. . The coating film was dried at 80° C. for 4 minutes. Thereafter, a PET separator with a thickness of 38 μm having a different peeling force from the separator was bonded to the separator, and the mixture was aged at 40° C. for 5 days to obtain a pressure-sensitive adhesive sheet with double-sided separators. In Examples 10 and 11 and Comparative Examples 5 and 6, the adhesive composition was directly applied onto a 50 μm thick PET separator.

(4) Various measurements and evaluations of the pressure-sensitive adhesive sheet The pressure-sensitive adhesive sheet obtained in (3) above was subjected to various measurements and evaluations by the following methods. Note that the measurement of "Tg of the surface layer portion of the adhesive layer" was carried out in Examples 9 to 11 and Comparative Example 4. The results obtained are shown in Tables 2 and 3.

<Gel fraction relative to acrylic adhesive polymer (B)>
0.2 g of the adhesive was sampled from the adhesive sheet, and the initial weight of the adhesive was weighed. The adhesive was immersed in 50 g of ethyl acetate and allowed to stand at room temperature for 16 hours. Thereafter, it was filtered through a 200-mesh wire mesh, and the residue remaining on the mesh was dried at 80° C. for 3 hours and weighed. The gel fraction for the acrylic adhesive polymer (B) was calculated from the initial mass and the mass of the residue using the following formula.
Gel fraction (%) = {(mass of residue) / [(initial mass) x (solid content of acrylic adhesive polymer (B)) / (solid content of entire adhesive composition)]} x 100

<Transparency (haze value)>
The release film was peeled off from the adhesive sheet, transferred to a glass plate (1 mm thick), and the other release film was peeled off. After standing for one day at 23°C and 50% RH, the haze value (%) was measured using a haze meter "Haze Meter NDH2000" (model name) manufactured by Nippon Denshoku Co., Ltd. The transparency of the formulation was evaluated.

<Tg of surface layer portion of adhesive layer>
The Tg of the composition forming the surface layer portion of the adhesive layer can be determined from the peak area ratio of O1s and C1s measured by X-ray photoelectron spectroscopy (XPS) of the adhesive sheet. Each mass fraction (w _A and w _B ) was calculated, and Tg of the surface layer portion was calculated based on the FOX formula.
Note that the XPS measurement was performed under the following conditions.
Equipment: PHI5000 VersaProbe manufactured by ULVAC-PHI
X-ray: Al-Kα (1486.6eV)
X-ray incident angle to the sample: 0° (angle with respect to the normal to the sample measurement surface)
Photoelectron detection angle: 45° (angle with respect to the normal to the sample measurement surface)

ここで、
（Ｏ／Ｃ）_Ａ＋Ｂ：粘着剤組成物を乾燥して得られた粘着剤層のＸＰＳ測定から求められるＯ１ｓとＣ１ｓのピーク面積比から算出される酸素原子数と炭素原子数の比
Ｗ_Ａ：ビニル重合体（Ａ）及びアクリル系粘着性ポリマー（Ｂ）の総量に対するビニル重合体（Ａ）の質量分率
Ｍ_ｗ－Ａ：ビニル重合体（Ａ）の全構成単量体単位の加重平均分子量
Ｍ_ｗ－Ｂ：アクリル系粘着剤組成物（Ｂ）の全構成単量体単位の加重平均分子量
Ｎ_Ｏ－Ａ：ビニル重合体（Ａ）を構成する全構成単量体の平均単量体構造式中に含まれる酸素原子数
Ｎ_Ｏ－Ｂ：アクリル系粘着性ポリマー（Ｂ）を構成する全構成単量体の平均単量体構造式中に含まれる酸素原子数
Ｎ_Ｃ－Ａ：ビニル重合体（Ａ）を構成する全構成単量体の平均単量体構造式中に含まれる炭素原子数
Ｎ_Ｃ－Ｂ：アクリル系粘着性ポリマー（Ｂ）を構成する全構成単量体の平均単量体構造式中に含まれる炭素原子数A specific method for calculating the mass fraction will be described below.
The ratio of the number of oxygen atoms and the number of carbon atoms calculated from the peak area ratio of O1s and C1s by XPS measurement is as shown in the following formula (1), consisting of a vinyl polymer (A) and an acrylic adhesive polymer (B). It is expressed as the ratio of the number of oxygen atoms to the number of carbon atoms present per unit weight of the surface layer of the adhesive layer formed from the adhesive composition.

here,
(O/C) _A+B : Ratio of the number of oxygen atoms to the number of carbon atoms calculated from the peak area ratio of O1s and C1s determined from XPS measurement of the adhesive layer obtained by drying the adhesive composition W _A : Mass fraction of vinyl polymer (A) with respect to the total amount of vinyl polymer (A) and acrylic adhesive polymer (B) M _w-A : Weighted average molecular weight of all constituent monomer units of vinyl polymer (A) Mw _-B : Weighted average molecular weight of all constituent monomer units of the acrylic pressure-sensitive adhesive composition (B) _NOA : Average monomer structure of all constituent monomers constituting the vinyl polymer (A) Number of oxygen atoms contained in the formula N _O-B : Average number of oxygen atoms contained in the monomer structural formula of all constituent monomers constituting the acrylic adhesive polymer (B) N _C-A : Vinyl heavy Average number of carbon atoms contained in the monomer structural formula of all constituent monomers constituting the aggregate (A) N _CB : Average number of carbon atoms contained in the monomer structural formula of all constituent monomers constituting the acrylic adhesive polymer (B) Number of carbon atoms contained in the mer structure

ここで、
（Ｏ／Ｃ）_Ａ：ビニル重合体（Ａ）を乾燥して得られたフィルムのＸＰＳ測定から求められるＯ１ｓとＣ１ｓのピーク面積比から算出される酸素原子数と炭素原子数の比

ここで、
（Ｏ／Ｃ）_Ｂ：アクリル系粘着性ポリマー（Ｂ）を乾燥して得られたフィルムのＸＰＳ測定から求められるＯ１ｓとＣ１ｓのピーク面積比から算出される酸素原子数と炭素原子数の比In addition, the number of carbon atoms and oxygen calculated from the peak area ratio of O1s and C1s determined by XPS measurement of the film obtained by drying each of the vinyl polymer (A) and the acrylic adhesive polymer (B) alone. The ratio of the number of atoms is represented by the following formulas (2) and (3), respectively.

here,
(O/C) _A : Ratio of the number of oxygen atoms to the number of carbon atoms calculated from the peak area ratio of O1s and C1s determined from XPS measurement of the film obtained by drying the vinyl polymer (A)

here,
(O/C) _B : Ratio of the number of oxygen atoms to the number of carbon atoms calculated from the peak area ratio of O1s and C1s determined from XPS measurement of the film obtained by drying the acrylic adhesive polymer (B)

さらに、上記で求めたＷ_Ａの値と下記式（５）から、アクリル系粘着性ポリマー（Ｂ）の質量分率（Ｗ_Ｂ）が算出される。

ここで、
Ｗ_Ｂ：ビニル重合体（Ａ）及びアクリル系粘着性ポリマー（Ｂ）の総量に対するアクリル系粘着性ポリマー（Ｂ）の質量分率The following formula (4) is derived from the above formulas (1) to (3), and from this, the mass fraction of the vinyl polymer (A) with respect to the total amount of the vinyl polymer (A) and the acrylic adhesive polymer (B) (W _A ) is calculated.

Furthermore, the mass fraction (W B ) of the acrylic adhesive polymer ( _B ) is calculated from the value of W _A determined above and the following formula (5).

here,
W _B : Mass fraction of acrylic adhesive polymer (B) with respect to the total amount of vinyl polymer (A) and acrylic adhesive polymer (B)

Regarding Example 9, each element in the above formula (4) is shown below.
(O/C) _A+B : 0.316 (actual value)
(O/C) _A : 0.290 (actual value)
(O/C) _B : 0.465 (actual value)
N _CA : From the number of carbon atoms in one molecule of MMA (5), the number of carbon atoms in one molecule of IBXMA (14), and the composition ratio, 5 × 89.9 (mol%) + 14 × 10.1 (mol%) = 5.91
N _C-B : 6×84.4 (mol%) from the number of carbon atoms in one molecule of MEA (6), the number of carbon atoms in one molecule of HEA (5), the number of carbon atoms in one molecule of BA (7), and the composition ratio. )+5×5.6(mol%)+7×10.1(mol%)+4×20.9(mol%)=6.05
M _w-A : From the molecular weight of MMA (100), the molecular weight of IBXMA (222), and the composition ratio, 100 x 89.9 (mol%) + 222 x 10.1 (mol%) = 112.3
M _w-B : From the molecular weight of MEA (130), the molecular weight of HEA (116), the molecular weight of BA (128) and the composition ratio, 130 x 84.4 (mol%) + 116 x 5.6 (mol%) + 128 x 10.1 (mol%) = 119.6
By substituting these values into equation (4), W _A =0.836 was obtained, and from equation (5), W _B =0.164 was obtained.

Next, the Tg of the surface layer portion was calculated from the surface composition obtained in the measurement according to the FOX equation expressed by the following equation (6), and a value of 73.8° C. was obtained.
1/[Tg of surface layer portion] (K)=WA/Tg _A +W _B /Tg _B (6)
here,
Tg _A : Tg of vinyl polymer (A) (108°C)
Tg _B : Tg of acrylic adhesive polymer (B) (-35°C)

<Vacuum-pressure forming test of decorative film>
A vinyl chloride decorative film (manufactured by Nippon Wavelock Co., Ltd., 200 μm thick) laminated with an adhesive sheet is shaped into an aluminum car shape using a vacuum-pressure forming machine (manufactured by Navitas Co., Ltd., NATS-0612B model). It was molded into a model (manufactured by TP Giken Co., Ltd., 200 mm x 100 mm x 40 mm). The molding conditions were two-stage molding, in which the film was preformed at a heating temperature of 80° C. or 90° C., and then steam pressure was applied at 130° C. for 15 seconds to adhere the decorative film to the car shape model. Thereafter, the appearance of the vacuum-pressure-formed decorative film was visually confirmed and evaluated according to the following criteria.
○: No shock line △: 1 or 2 shock lines ×: 3 or more shock lines

Examples 2 to 13 and Comparative Examples 1 to 6
As shown in Tables 2 and 3, vacuum-pressure forming was performed in the same manner as in Example 1, except that the composition of the adhesive composition and the type and thickness of the thin film layer were changed. In Comparative Examples 5 and 6, no thin film layer was formed). The results are shown in Tables 2 and 3.

Note that the numbers for each component of the adhesive composition in Tables 2 and 3 mean parts by mass of solid content. Further, the abbreviations in Tables 2 and 3 have the following meanings.
◆Crosslinking agent
・D-110N: Mitsui Chemicals Takenate D-110N, trimethylolpropane adduct of metaxylylene diisocyanate, solid concentration 75.0%, NCO content 11.5%
・CO-L: Coronate L manufactured by Tosoh Corporation, trimethylolpropane adduct of tolylene diisocyanate, solid concentration 75.0%, NCO content 13.2%
◆Polyolefin resin
・C-1: Acid-modified polyolefin resin, Toyobo Co., Ltd. Toyotac PMA-T, maleic anhydride-modified propylene/butene copolymer, degree of modification 1.5% by mass, weight average molecular weight 55,000, melting point 95 ℃
・C-4: Acid-modified polyolefin resin, Aronmelt PPET-1303S manufactured by Toagosei Co., Ltd., softening point 100°C
・C-6: Acid-modified polyolefin resin, Toyobo Co., Ltd. Toyotac PMA-L, maleic anhydride-modified propylene/butene copolymer, degree of modification 1.5% by mass, weight average molecular weight 75,000, melting point 70 ℃
・C-7: Acid-modified polyolefin resin, Auroren 200S manufactured by Nippon Paper Industries, maleic anhydride-modified ethylene vinyl acetate, weight average molecular weight 65,000, melting point 60-70°C
・C-8: Chlorinated polyolefin resin: Nippon Paper Industries Co., Ltd. Super Chron 814HS, chlorinated propylene, degree of chlorination modification 41% by mass, weight average molecular weight 20,000, melting point 65°C
◆Rosin ester resin
・C-2: Pine Crystal KE-311 manufactured by Arakawa Chemical Industry Co., Ltd., softening point 90-100°C
◆Polyester resin
・C-3: Aronmelt PES-320SK manufactured by Toagosei Co., Ltd., softening point 110°C
・C-5: Pluscoat Z-730 manufactured by Gooo Kagaku Kogyo Co., Ltd., weight average molecular weight 3,000, softening point 80-85°C

As is clear from the results of Examples 1 to 13, when the pressure-sensitive adhesive sheet of the present disclosure was applied to vacuum-pressure forming of a decorative film, it was excellent in suppressing shock lines (Table 2). Among these, Examples 1 to 5, 8, 9, 12, and 13 in which the melting point, softening point, or Tg of the thin film layer is over 85°C, and those calculated from the composition obtained by X-ray photoelectron spectroscopy of the thin film layer. Example 11, in which the Tg was higher than 85°C, had a great shock line suppressing effect.
On the other hand, in Comparative Examples 1 to 6 using pressure-sensitive adhesive sheets that do not have the thin film layer specified in the present disclosure, shock lines occurred and were not suitable for vacuum-pressure forming (Table 3).

The pressure-sensitive adhesive sheet of the present disclosure can follow complicated shapes such as curved surfaces and uneven portions and suppress the occurrence of shock lines in vacuum-pressure forming of decorative films. Therefore, the adhesive sheet of the present disclosure is suitable as a material for decorating various molded products such as resin products, metal products, ceramic products, glass products, and the like. Specifically, home appliances; housing equipment such as toilets, bathrooms, doors, and walls; automobile interior and exterior parts such as bumpers, dashboards, doors, roofs, and bonnets; electronic components, nursing care and medical supplies, and interior and exterior parts of ships. It can be suitably used for manufacturing interior and exterior parts of aircraft.

Claims (9)

A pressure-sensitive adhesive sheet for vacuum-pressure forming, which has an adhesive layer formed from a pressure-sensitive adhesive composition and a thin film layer, and the thin film layer side is pressure-bonded to an adherend during vacuum-pressure forming,
The thin film layer constitutes a surface layer portion of the adhesive layer, and has a Tg of 70° C. or higher calculated from the composition of the surface layer portion of the adhesive layer obtained by X-ray photoelectron spectroscopy analysis of the adhesive layer. Adhesive sheet for vacuum pressure forming. A pressure-sensitive adhesive sheet for vacuum-pressure forming, which has an adhesive layer formed from a pressure-sensitive adhesive composition and a thin film layer, and the thin film layer side is pressure-bonded to an adherend during vacuum-pressure forming,
The thin film layer is disposed on at least one side of the adhesive layer, is thinner than the adhesive layer, and has a melting point, softening point, or glass transition temperature (Tg) of 70° C. or higher,
An adhesive sheet for vacuum-pressure forming, wherein the thin film layer contains at least one selected from the group consisting of polyolefin resins and rosin ester resins . The adhesive composition is an acrylic adhesive composition and includes a vinyl polymer (A) and an acrylic adhesive polymer (B),
The vinyl polymer (A) has a Tg of 30°C or more and 200°C or less, a number average molecular weight of 500 to 10,000, and 0.5 parts by mass per 100 parts by mass of the acrylic adhesive polymer (B). Contains not less than 60 parts by mass,
The adhesive layer has a first Tg, which is the Tg of the entire adhesive layer, of −80° C. or more and 20° C. or less,
1 . The second Tg, which is the Tg calculated from the composition of the surface layer portion of the adhesive layer obtained by X-ray photoelectron spectroscopy of the adhesive layer, is higher than the first Tg by 30° C. or more. Adhesive sheet for vacuum pressure forming described in . The pressure-sensitive adhesive sheet for vacuum-pressure forming according to claim 3, wherein the vinyl polymer (A) is contained in a higher concentration in at least one surface layer portion of the pressure-sensitive adhesive layer. The pressure-sensitive adhesive sheet for vacuum-pressure forming according to claim 2 , wherein the pressure-sensitive adhesive composition is an acrylic pressure-sensitive adhesive composition. A method for producing a pressure-sensitive adhesive sheet for vacuum-pressure forming according to claim 2 or 5 , comprising:
A method for producing a pressure-sensitive adhesive sheet for vacuum-pressure forming, comprising forming the thin film layer on a release film. A method for producing a pressure-sensitive adhesive sheet for vacuum-pressure forming, the pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer formed from a pressure-sensitive adhesive composition and a thin film layer, the thin film layer side being pressure-bonded to an adherend during vacuum-pressure forming. ,
forming the thin film layer;
forming the adhesive layer by applying the adhesive composition on the thin film layer,
The thin film layer is thinner than the adhesive layer, and the melting point, softening point, or glass transition temperature (Tg) of the thin film layer is 70° C. or higher,
A method for producing a pressure -sensitive adhesive sheet for vacuum-pressure forming, wherein the thin film layer contains at least one selected from the group consisting of a polyolefin resin and a rosin ester resin . A decorative film comprising the pressure-sensitive adhesive sheet for vacuum-pressure forming according to any one of claims 1 to 5. A decorated molded article obtained by adhering the decorative film according to claim 8 to a molded article.