TW201900805A - Adhesive sheet for decorative molding - Google Patents

Abstract

Provided is an adhesive sheet for decorative molding, which exhibits excellent adhesiveness and is not susceptible to the occurrence of cracks and wrinkles after bonding, while being also not susceptible to the occurrence of loss of adhesion and separation of the sheet. An adhesive sheet for decorative molding according to the present invention is provided with a laminate in which a base material and an adhesive layer are laminated; and the base material contains a polymethyl methacrylate, while the adhesive layer contains a tackifying agent that contains a polymethyl methacrylate.

Description

Adhesive sheet for decoration molding

FIELD OF THE INVENTION The present invention relates to an adhesive sheet that can be used for decorative molding.

BACKGROUND OF THE INVENTION Three-dimensional surface decoration molding (3D decoration molding) is a molding technology for decorating the surface of a substrate by bonding a decoration film or the like to a three-dimensionally shaped member. In recent years, for electronic equipment materials, etc. For extensive use. For 3D decorative molding, for example, a decorative film (adhesive sheet for 3D decorative decoration) laminated with an adhesive sheet is attached to a member having a curved surface such as a spherical surface or a concave-convex surface, and the surface is heated to 140 At about ℃, the two are bonded together. At this time, since a curved portion having a large R (degree of curved surface) or the like requires high drawability on the 3D decorative adhesive sheet itself, it is also important to select a material for forming the adhesive sheet.

The 3D decorative sheet is mainly formed of a base material and an adhesive layer, and conventionally, polyvinyl chloride (PVC) is used as the base material. Recently, consideration should be given to reducing the burden on the environment, and the use of polyethylene terephthalate (PET), polyethylene (PE), or polypropylene (PP) substrates is more common. However, since PE or PP substrates have poor transparency and weather resistance and poor adhesion with adhesives, in order to improve this point, it is proposed to use a difluoroethylene resin with excellent flexibility and transparency as a 3D additive. Base material of decorative adhesive sheet (refer to Patent Document 1 and the like). In addition, in order to improve the adhesion between the PE or PP substrate and the adhesive, there is also proposed an adhesive sheet formed by mixing a monoalcohol with an isocyanate-crosslinking adhesive (see Patent Document 2 and the like). Prior Art Literature Patent Literature

Patent Document 1: Japanese Patent Laid-Open No. 2003-236998 Patent Document 2: Japanese Patent Laid-Open No. 2016-180019

SUMMARY OF THE INVENTION Problems to be Solved by the Invention However, as with the technique disclosed in Patent Document 1, in the method using a difluoroethylene resin, there is a problem that difluoroethylene will generate toxic gas after combustion, and this is a safety issue. Leaving issues in perspective. Moreover, even with the technology disclosed in Patent Document 2 and the like, since PE or PP is used for the substrate, the problems of poor transparency and weather resistance cannot be solved. In particular, 3D decorative molding also applies a large amount of stress and load to the curved surface of a component that is in close contact with a three-dimensional shape. Therefore, there is a problem that the adhesive sheet floats when there is insufficient adhesion. In addition, when the base material of the adhesive sheet is a material such as PET, there is a problem that wrinkles and cracks occur on the adhesive sheet because the pullability of the adhesive sheet is insufficient.

The present invention has been made in view of the foregoing, and an object thereof is to provide an adhesive sheet for decorative molding. The adhesive sheet for decorative molding has excellent adhesiveness, and it is difficult to generate wrinkles and cracks after bonding, and it is also difficult to cause floating. And peeling. Means to solve the problem

The inventors of the present case made repeated efforts in order to achieve the foregoing objectives, and found that the foregoing can be achieved by using a substrate containing polymethylmethacrylate and an adhesive layer containing a polymethylmethacrylate-containing tackifier. The purpose is to complete the present invention.

That is, the present invention includes, for example, the inventions described in the following items. Item 1. An adhesive sheet for decoration molding, comprising a laminated body having a base material and an adhesive layer laminated; the aforementioned substrate contains polymethyl methacrylate; the aforementioned adhesive layer contains polymethyl methacrylate Adhesive. Item 2. The decorative sheet for decoration molding according to item 1, wherein the weight average molecular weight (Mw) of the polymethyl methacrylate contained in the aforementioned tackifier is from 500 to 50,000. Item 3. The decorative sheet for decoration molding according to item 1 or 2, wherein the adhesive layer contains a crosslinked structure of a base polymer (A) other than polymethyl methacrylate; and the base polymer ( The structural unit of A) contains a (meth) acrylate monomer unit (a1) and a (meth) acrylic monomer unit (a2) having a crosslinkable functional group. Item 4. The adhesive sheet for decoration molding according to any one of Items 1 to 3, wherein the water contact angle of the surface of the aforementioned substrate opposite to the side of the adhesive layer is 40 ° to 95 °. Item 5. The decorative sheet for decoration molding according to any one of items 1 to 4, wherein a separator is attached to a surface of the adhesive layer opposite to the substrate side. Invention effect

The decorative sheet for decorative molding of the present invention is excellent in adhesion, hardly causes wrinkles and cracks after bonding, and is difficult to float and peel.

Embodiments for Carrying Out the Invention Embodiments of the present invention will be described in detail below. In addition, in this specification, expressions including "contained" and "contained" include concepts such as "contained", "included", "consisting essentially of it", and "consisting of only".

The decorative sheet for decorative molding of the present invention has a laminated body with a base material and an adhesive layer, and the substrate contains polymethyl methacrylate, and the adhesive layer contains polymethyl methacrylate. Agent. In addition, the adhesive sheet for decoration molding of this invention may be abbreviated as "adhesive sheet" hereafter.

The substrate is a component for supporting the adhesive layer.

In addition, in the following, in order to distinguish the polymethylmethacrylate (PMMA) contained in the substrate from the PMMA contained in the tackifier, the PMMA contained in the substrate is referred to as "PMMA1", and The PMMA contained in the agent is referred to as "PMMA2".

1 (a) to (d) are cross-sectional views showing an example of a laminated structure of a base material and an adhesive layer of the decorative sheet for decorative molding of the present invention. As shown in the form of Fig. 1 (a), as long as the base material does not impair the 3D decoration, it can be composed of PMMA1 alone, and it can also be a copolymer or blend of PMMA1 and other materials. As other materials in the copolymer or blend substrate, well-known materials used as film substrates can be widely used, for example, acrylic resins other than PMMA, polystyrene, PE, PP, PET, and polyamide can be cited. , Polyimide, silicone resin, polycarbonate (PC), styrene rubber, isoprene rubber, isobutyl rubber, ethylene-propylene-diene rubber, and acrylic rubber. Moreover, as shown in FIG. 1 (b), the substrate may be a laminated substrate of PMMA1 and other materials. As other materials in the laminated substrate, well-known materials used as film substrates can be widely used, and examples thereof include acrylic resins other than PMMA, polystyrene, PE, PP, PET, polyimide, polyimide, Silicone resin and polycarbonate (PC).

When PMMA1 is copolymerized or blended with other materials, the content of PMMA1 relative to the total mass of the substrate is 70% by mass or more, and preferably 80% by mass or more, more preferably 90% by mass or more.

When the substrate is a laminated substrate of PMMA1 and other materials, the thickness ratio of PMMA1 to other materials is 10% or more, and preferably 15% or more, and more preferably 20% or more relative to the overall PMMA1 of the laminated substrate. In addition, PMMA1 used for the laminated substrate may be composed only of PMMA1, and may also be a copolymer of PMMA1 and other materials.

The water contact angle of the surface of the substrate opposite to the surface to which the adhesive layer is to be attached, that is, the decorated molding surface, is 40 ° to 95 °, and preferably 50 ° to 90 °. As long as the water contact angle is within the aforementioned range, excellent printability can be imparted. As a method of setting the water contact angle of the base material to the aforementioned range, a method of laminating a desired resin that incorporates the aforementioned water contact angle range; a method of setting a desired easy-adhesive layer that incorporates the aforementioned contact angle range; and , A method of performing corona irradiation so that it can be included in the aforementioned contact angle range, and the like.

Figure 1 (c) is a single-layer base material (PMMA1) with an adhesive sheet for decorative molding when an easy-adhesive layer is provided. At this time, the easy-adhesive layer is provided on the side of the substrate opposite to the adhesive layer side On the surface. FIG. 1 (d) is an adhesive sheet for decorative molding when the substrate is the aforementioned laminated substrate. At this time, it is also easy to adhere to the surface of the laminated substrate opposite to the side of the adhesive layer. The type of the easy-adhesive layer is not particularly limited. For example, the following easy-adhesive layers can be widely used: a well-known easy-adhesive layer that can be suitably used as an adhesive sheet and an easy-adhesive layer to impart printability.

The substrate can be formed by, for example, molding a raw material containing PMMA1. Alternatively, a commercially available PMMA film can be used as the substrate. When a base material containing PMMA1 is used for molding the substrate, the molding method is not particularly limited, and a well-known molding method can be used. In addition, the kind of the raw material containing PMMA1 is not particularly limited. The raw material containing PMMA1 may be only PMMA, or PMMA1 may also contain other materials mentioned above.

The weight average molecular weight (Mw) of PMMA1 is not particularly limited. For example, it can be set to be the same as that of a general PMMA film.

The thickness of the substrate is not particularly limited, and is, for example, 5 to 100 μm.

The base material is formed in a sheet shape or a film shape. The surface of the substrate can be made flat, or it can have unevenness. The substrate may have any of a single-layer structure and a multilayer structure.

The adhesive layer is a layer formed on a substrate, and is a layer for exerting adhesiveness. The adhesive layer may be directly formed on the substrate, and as long as the effect of the present invention is not hindered, other layers may be present between the substrate and the adhesive layer.

The adhesive layer can be formed using an adhesive composition described later. The adhesive composition contains a PMMA2-containing tackifier. The tackifier used in the present invention is a component that functions as an auxiliary agent for imparting tackiness to an adhesive layer, that is, a component generally referred to as a "tackifier". In the adhesive layer, the content of the tackifier can be set as follows: per 100 parts by mass of the base polymer (A) described later, the content of the tackifier is 1 to 35 parts by mass, preferably 5 to 30 parts by mass, and more preferably 10 ~ 25 parts by mass. At this time, excellent adhesiveness can be imparted to the adhesive layer, and even after the adhesive sheet has been attached to a member to be decorated in 3D, wrinkles and cracks are less likely to occur, and it is more difficult to float. Lifting and peeling.

The content ratio of PMMA2 contained in the tackifier is 50% by mass or more, preferably 80% by mass or more, preferably 90% by mass or more, and more preferably 99% by mass or more relative to the total mass of the tackifier. The content ratio of PMMA2 contained in the tackifier can be set to 100% by mass.

The type of polymethyl methacrylate (PMMA2) contained in the tackifier is not particularly limited as long as it does not hinder compatibility with the base polymer. For example, the well-known PMMA can be widely used. PMMA2 can be made of commercially available materials, for example, or can be produced by well-known polymerization methods such as radical polymerization.

PMMA2 can be a homopolymer of polymethyl methacrylate, or, as long as the effect as an adhesion promoter is not hindered, it can also be a copolymer of methyl methacrylate and other acrylic monomers . Examples of other acrylic monomers include methacrylic acid esters containing N-alkyl substituted amino groups such as dimethylamine ethyl methacrylate (DMAEMA).

When PMMA2 is a copolymer of methyl methacrylate and other acrylic monomers, the content of methyl methacrylate can be set to 70% by mass or more relative to the total mass of methyl methacrylate and other acrylic monomers. It is preferably 80% by mass or more, and more preferably 90% by mass or more.

The weight average molecular weight (Mw) of PMMA2 is not particularly limited. For example, it can be set to 500 to 50,000. At this time, the adhesive performance of the adhesive sheet will be more excellent, and even after the adhesive sheet is attached to the component to be decorated in 3D, wrinkles and cracks are more difficult to occur, and it is also more difficult for floating and Peel off.

The tackifier may contain components other than PMMA2 as long as the effects of the present invention are not impaired. As other components, well-known tackifying resins suitable for use in adhesive sheets can be widely used, and examples thereof include styrene resins, terpene resins, and turpentine.

The adhesive layer contains components other than the tackifier. For example, in addition to the tackifier, the adhesive layer may also contain a polymer that will serve as a matrix component of the adhesive layer.

Specifically, the adhesive layer may contain a crosslinked structure of a base polymer (A) other than polymethylmethacrylate. The constituent units of the base polymer (A) may include a (meth) acrylate monomer unit (a1) and a (meth) acrylic monomer unit (a2) having a crosslinkable functional group. The crosslinked structure of the base polymer (A) can become a matrix component of the adhesive layer.

The crosslinked structure of the base polymer (A) can be formed, for example, by reacting a base polymer (A) other than PMMA with a cross-linking agent (B) described later. The crosslinking agent (B) is a crosslinking agent capable of reacting with the base polymer (A).

The "base polymer (A) other than PMMA" as used herein means that the base polymer (A) is not a PMMA homopolymer. That is, when the base polymer (A) is a copolymer, a PMMA component may be contained as a constituent component of the copolymer.

The aforementioned (meth) acrylate monomer unit (a1) represents a repeating structural unit formed when the (meth) acrylate monomer is polymerized, and does not represent the monomer itself. Similarly, the (meth) acrylic monomer unit (a2) having a crosslinkable functional group means a repeating structural unit formed when the (meth) acrylic monomer having a crosslinkable functional group is polymerized, and It does not mean the monomer itself.

In addition, the "(meth) acrylfluorenyl" referred to in this specification means "acrylfluorenyl or methacrylfluorenyl", and "(meth) acryl" means "propylene or methacryl". For example, the description of "(meth) acrylic acid" is synonymous with the description of "acrylic or methacrylic acid".

The (meth) acrylate monomer unit (a1) can be formed with a (meth) acrylate monomer. Herein, the (meth) acrylate mono system is said to have no monomer having a functional group that can react with the crosslinking agent (B).

The type of the (meth) acrylate monomer is not particularly limited, and for example, a well-known (meth) acrylate monomer can be used. Specific examples of the (meth) acrylate monomer include a hydrocarbon group compound having 1 to 20 carbon atoms in the ester portion of the (meth) acrylate. The hydrocarbon group may have any of a linear structure, a branched structure, a cyclic structure, and a cage structure. The hydrocarbon group may be any of a saturated hydrocarbon group and an unsaturated hydrocarbon group. The hydrocarbon group may have a substituent.

More specific examples of the (meth) acrylate monomer include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, and (meth) acrylic acid. Isopropyl ester, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isobutyl (meth) acrylate, tertiary butyl (meth) acrylate, n-hexane (meth) acrylate Ester, cyclohexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, isoamyl (meth) acrylate, adamantyl (meth) acrylate, and (meth) ) Phenyl acrylate and the like.

The base polymer (A) may contain only one kind of (meth) acrylate monomer unit (a1) or may contain two or more kinds.

The (meth) acrylic monomer unit (a2) having a crosslinkable functional group can be formed with a (meth) acrylic monomer having a crosslinkable functional group. The (meth) acrylic acid monosystem having a crosslinkable functional group referred to herein has a (meth) acrylic monomer that has a functional group that reacts with a crosslinking agent (B), and is the same as the (meth) Different monomers of acrylate monomer.

The cross-linkable functional group in the (meth) acrylic monomer having a cross-linkable functional group is not particularly limited as long as it is a functional group that can react with the cross-linking agent (B). The cross-linking agent ( The type of B) is appropriately selected. Examples of the crosslinkable functional group include a carboxyl group, a hydroxyl group, an amine group, a sulfonyl group, a sulfonic acid group, a sulfonic acid group, an epoxy group, a chloro group, and a fluoro group.

The (meth) acrylic monomer having a crosslinkable functional group may have one crosslinkable functional group in one molecule, or may have two or more crosslinkable functional groups. When the (meth) acrylic monomer having a crosslinkable functional group has two or more crosslinkable functional groups in one molecule, the crosslinkable functional groups may be the same kind or different kinds.

Specific examples of the (meth) acrylic monomer having a crosslinkable functional group include (meth) acrylic acid, maleic acid, maleic anhydride, itaconic acid, and fumaric acid. Acid, citraconic acid, 2- (meth) acryloxyethyl phthalic acid, 2- (meth) acryloxyethyl succinic acid, 2- (meth) acryloxyethyl Maleic acid, carboxyethyl (meth) acrylate, carboxypolycaprolactone mono (meth) acrylate, (meth) acrylamide, vinyl alcohol, hydroxyalkyl (meth) acrylate, and Hydroxyalkyl (meth) acrylamide and the like.

Examples of the hydroxyalkyl (meth) acrylate include 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, and (meth) ) 5-hydroxypentyl acrylate, 2-hydroxybutyl (meth) acrylate, 2,2-dimethyl 2-hydroxyethyl (meth) acrylate, 3-chloro 2-hydroxypropyl (methyl ) Acrylate, 2-hydroxy 3-phenoxypropyl (meth) acrylate, 2-hydroxy 3-phenoxypropyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, and the like. Examples of the hydroxyalkyl (meth) acrylamide include N-hydroxypropyl (meth) acrylamide.

The base polymer (A) may contain only one (meth) acrylic monomer unit (a2) having a crosslinkable functional group, or may contain two or more kinds.

Hereinafter, the (meth) acrylate monomer unit (a1) will be simply referred to as "monomer unit (a1)". The (meth) acrylic monomer unit (a2) having a crosslinkable functional group is simply referred to as "monomer unit (a2)".

The base polymer (A) may contain other monomer units (a1) and monomer units (a2) as long as the effects of the present invention are not impaired.

Each of the total constituent units forming the base polymer (A) can be set to a content ratio of 50 to 99.9% by mass, preferably 60 to 99.5% by mass, and more preferably 70 to 99.0. quality%.

The base polymer (A) can be a so-called random copolymer in which the monomer units (a1), the monomer units (a2), and the aforementioned other monomer units are randomly arranged. Alternatively, the base polymer (A) may have another structure such as a block polymer.

The crosslinking agent (B) is a component for crosslinking the base polymer (A). In particular, the crosslinking agent (B) is a component capable of reacting with the crosslinkable functional group of the monomer unit (a2) in the base polymer (A).

The type of the crosslinking agent (B) is not particularly limited as long as it can react with the crosslinkable functional group of the monomer unit (a2), and well-known crosslinking agents can be widely used.

Examples of the crosslinking agent (B) include epoxy crosslinking agents and isocyanate crosslinking agents.

The type of the isocyanate crosslinking agent is not particularly limited, and well-known compounds can be widely used. Examples of such an isocyanate crosslinking agent include toluene diisocyanate, chlorophenylene diisocyanate, diphenylmethane diisocyanate, butylene diisocyanate, hexamethylene diisocyanate, and tetramethylene diisocyanate. Polyisocyanates such as isocyanate, hydrogenated diphenylmethane diisocyanate, xylene diisocyanate; cycloaliphatic diisocyanate, cyclohexyl diisocyanate, and other alicyclic isocyanates; 2,4-methylphenylphenyl diisocyanate, 2, Aromatic isocyanates such as 6-methylenephenyl diisocyanate and 4,4'-diphenylmethane diisocyanate. The isocyanate crosslinking agent may be used alone or as a mixture of two or more kinds. Moreover, it is preferable to use a trifunctional derivative such as an adduct of a diisocyanate, a nurate body, and a biuret body as an isocyanate crosslinking agent.

Examples of the epoxy crosslinking agent include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, and propylene glycol diglycidyl. Glycidyl ester, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, N, N, N ', N'-tetraglycidyl-m-xylene Amine, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexanone, trimethylolpropane polyglycidyl ether, diglycerol polyglycidyl ether, polyglycerol polyglycidyl ether, Sorbitol polyglycidyl ether and the like.

Among them, N, N, N ', N'-tetraglycidyl-m-xylylenediamine and 1,3-bis (N, N-glycidylaminomethyl) cyclohexyl are 4-functional. Ketones are preferred because they exhibit a crosslinking effect in a small amount.

The content of the crosslinked structure of the base polymer (A) contained in the adhesive layer and the PMMA2 contained as the tackifier is not particularly limited. For example, per 100 parts by mass of the aforementioned cross-linked structure in the adhesive layer, the PMMA2 contained as the tackifier is 1 to 35 parts by mass, preferably 5 to 30 parts by mass, and more preferably 10 to 25 parts by mass. At this time, excellent adhesiveness can be imparted to the adhesive layer, and even after the adhesive sheet has been attached to a component to be decorated in 3D, wrinkles and cracks are less likely to occur, and it is more difficult to float. Lifting and peeling.

The thickness of the adhesive layer is 5 to 50 μm, preferably 8 to 45 μm, and more preferably 10 to 35 μm.

The adhesive layer may be formed on the entire surface of the substrate, but may not be formed on the entire surface of the substrate as long as the effect of the present invention is not impaired.

The method for forming the adhesive layer is not particularly limited. For example, it can be formed by a method having a step of forming an adhesive layer using an adhesive composition (hereinafter referred to as "adhesive layer forming step"). In the step of forming the adhesive layer, for example, an adhesive layer can be formed on the substrate by coating the adhesive composition on the substrate and curing it. Thereby, a laminated body formed of a base material and an adhesive layer can be obtained.

When the adhesive composition is used to form an adhesive layer, the adhesive composition contains a PMMA2-containing tackifier as an essential component. As the adhesive composition, for example, a material containing the aforementioned base polymer (A), the aforementioned crosslinking agent (B), and the aforementioned tackifier can be used.

The base polymer (A) can be obtained by a polymerization reaction of a raw material containing the (meth) acrylic acid ester monomer and the (meth) acrylic acid monomer having a crosslinkable functional group. The raw material may contain 50 to 99.9% by mass of the (meth) acrylic acid ester monomer relative to the total amount of the (meth) acrylic acid ester monomer and the (meth) acrylic acid monomer having a crosslinkable functional group (readily used) In order to form a monomer of the monomer unit (a1)), it is preferable to contain 60 to 99.5% by mass, and more preferably 70 to 99.0% by mass.

For the aforementioned polymerization reaction, for example, a well-known polymerization initiator can be used. Examples of the polymerization initiator include azobisisobutyronitrile, 2,2'-azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride, and 1,1'-azo Bis (cyclohexanecarbonitrile), di-tertiary butyl peroxide, tertiary butyl hydroperoxide, benzoyl peroxide, ammonium persulfate, photopolymerization initiator (IRGACURE (registered trademark) series, etc.) Wait. The amount of the polymerization initiator used is also not limited, and it can be set to the same conditions as the well-known polymerization methods.

In the aforementioned polymerization reaction, a solvent may be used as necessary. The type of the solvent is not particularly limited. For example, it can be widely used for a well-known organic solvent used in polymerization. Examples include: ester compounds such as ethyl acetate and butyl acetate; ketones such as acetone and methyl ethyl ketone; aliphatic hydrocarbons such as hexane; and aromatic compounds such as toluene, xylene, and benzene. The amount of the solvent used in the polymerization reaction is not particularly limited.

The aforementioned polymerization reaction can be obtained by a well-known polymerization method. The polymerization method may be, for example, solution polymerization, block polymerization, suspension polymerization, emulsion polymerization, or the like.

In the aforementioned polymerization reaction, the polymerization reaction can be performed under an inert gas environment such as nitrogen.

The reaction time and reaction temperature of the polymerization reaction are also not limited, and can be appropriately set according to the type and amount of the monomers used. For example, the polymerization reaction can be performed under the conditions of 20 to 100 ° C and 1 to 24 hours.

The method for preparing the adhesive composition is not particularly limited, and it can be prepared by mixing the base polymer (A), the cross-linking agent (B), and the tackifier at a predetermined blending ratio. The mixing method is not particularly limited. For example, a commercially available mixer can be used.

The adhesive composition may contain 0.001 to 5 parts by mass of the aforementioned crosslinking agent (B) per 100 parts by mass of the base polymer (A), and preferably 0.005 to 3 parts by mass, and more preferably 0.01 to 1 part by mass.

The adhesive composition may contain other components in addition to the base polymer (A), the cross-linking agent (B), and the tackifier as required. Examples of other components include a silane coupling agent, a cross-linking accelerator, an antistatic agent, a light stabilizer (absorption) agent, a dispersion stabilizer, a preservative, a viscosity modifier, a metal corrosion inhibitor, and a solvent.

In the step of forming the adhesive layer, the method of applying the adhesive composition to the substrate is not particularly limited, and for example, a well-known coating method can be widely used. The thickness of the coating film formed by applying the adhesive composition is also not limited, and can be appropriately set according to the thickness of the adhesive layer of the target adhesive sheet.

In the step of forming the adhesive layer, the adhesive layer may be formed by hardening a coating film of the adhesive composition after the adhesive composition is coated on the substrate. The hardening method is not particularly limited. For example, a conventional hardening method of an adhesive composition can be widely used. For example, the method of heating and hardening a coating film is mentioned. For example, the temperature during heating can be set to 50 to 200 ° C, and preferably 80 to 150 ° C. As long as the heating time is set, the solvent will volatilize, and the residual solvent concentration of the adhesive layer will be less than 1000 ppm. From the viewpoint of the concentration of the adhesive composition and the thickness of the desired adhesive layer, etc., it should be within the aforementioned range. And set appropriately within 1 ~ 30 minutes.

By the aforementioned hardening, the cross-linking agent (B) in the adhesive composition reacts with the cross-linkable functional group of the monomer unit (a2) in the base polymer (A) to perform the base polymer (A). Crosslinking reaction. Thereby, an adhesive layer containing the crosslinked structure of the base polymer (A) is formed. The adhesive layer also contains PMMA2 as a tackifier.

After the aforementioned coating film is cured, the cured product may be aged under a predetermined environment as required.

An adhesive layer is formed through the above adhesive layer forming step. In the step of forming the adhesive layer, the layered body contained in the adhesive sheet can be directly produced by forming the layer of adhesive on the substrate, and the step of forming the layer of adhesive.

The adhesive sheet may also have a separating member.

For example, a pressure-sensitive adhesive sheet may have a separator attached to a surface of the adhesive layer opposite to the substrate side. The separating member is a component for protecting the adhesive layer of the adhesive sheet.

The type of the separator is not particularly limited, and a well-known film that has been used as a separator of an adhesive sheet in the past can be widely used. For example, a well-known release-treated polyester film can be used as the separator of the adhesive sheet.

When the adhesive sheet has a separating member, the adhesive sheet is formed by sequentially stacking the substrate, the adhesive layer, and the separating member.

The adhesive sheet may be formed only of the base material and the adhesive layer (that is, the laminated body), or may be formed only by a layer composed of the laminated body and the aforementioned separator, or may further include a laminated body and the aforementioned separator Layers.

The manufacturing method of an adhesive sheet is not specifically limited. For example, a method having the aforementioned step of forming an adhesive layer can be used. A laminated body is formed through the step of forming the adhesive layer, and can be obtained as an adhesive sheet. The conditions for forming the adhesive layer are the same as those described above, and the adhesive composition used is also as described above.

In addition, when the adhesive sheet has a separating member, for example, it can be prepared by forming a laminated body through an adhesive layer forming step in advance, and bonding the surface on the side of the adhesive layer of the laminated body with Separating the pieces to obtain an adhesive sheet in which the adhesive layer is protected by the separating pieces. The method of bonding the surface on the adhesive layer side of the laminated body and the separator is not particularly limited, and for example, a well-known method can be widely used.

Also, as another aspect, when the adhesive sheet has a separating member, it can be prepared by: firstly forming an adhesive layer on the separating member through the aforementioned adhesive layer forming step, and then, by using the adhesive layer The substrate is adhered on top, and an adhesive sheet with an adhesive layer protected by a separator is prepared. The method for bonding the adhesive layer and the substrate is not particularly limited, and for example, a well-known method can be widely used.

The adhesive sheet of the present invention can be used as an adhesive sheet for three-dimensional surface decoration molding (3D decorative molding). For example, the adhesive sheet of the present invention can be applied to the substrate surface (the surface opposite to the adhesive layer). For decorative printing, and as a decorative film.

The type of decoration printing is not particularly limited, and a well-known printing method can be adopted. Examples include screen printing, inkjet printing, coating, vacuum film formation, plating, transfer and lamination of decorative films, and laminated films printed with embedded metal patterns and black color. Decorative films for printed films, etc.

The decorative film having the adhesive sheet of the present invention can be used as a film for 3D decorative molding. The surface on the side of the adhesive layer of the decorative film is adhered to a three-dimensionally shaped member to be 3D decoratively molded, thereby giving the three-dimensionally shaped member design. When the adhesive sheet has a separating member, the separating member is peeled from the adhesive layer to expose the adhesive layer, and the surface of the adhesive layer is adhered to the three-dimensionally shaped member.

Since the adhesive sheet of the present invention contains PMMA in the base material, it has excellent drawability, and therefore has excellent adhesion to a three-dimensional shape member, so that wrinkles and cracks are unlikely to occur after bonding, and the printability is excellent.

In addition, since the adhesive sheet of the present invention also contains PMMA (PMMA2) as an adhesive in the adhesive layer, the affinity between the adhesive layer and the substrate is also high, and the glass transition temperature of the entire adhesive layer is also variable. high. Thereby, high adhesiveness can be maintained even at high temperatures, and even if the decorative film using the adhesive sheet of the present invention is subjected to 3D decorative molding, it is difficult for the adhesive sheet to float and peel, and has high reliability. Examples

Hereinafter, the present invention will be described more specifically with reference to the examples, but the present invention is not limited to the aspects of the examples. In addition, unless otherwise stated, the blending amount of a solution or dispersion means the solid blending amount (parts by mass).

(Production Example 1) A monomer (a1) consisting of 80 parts by mass of n-butyl acrylate and 17 parts by mass of methyl acrylate, a monomer (a2) consisting of 3 parts by mass of acrylic acid, and 150 parts by mass of ethyl acetate (EtAc) And 20 parts by mass of methyl ethyl ketone (MEK) were put into a reaction vessel having a stirrer, a nitrogen introduction pipe, a thermometer, and a reflux cooling pipe, and the temperature was raised to 70 ° C. while introducing nitrogen gas. Next, 0.05 parts by mass of a polymerization initiator, azobisisobutyronitrile (AIBN), was added, and a polymerization reaction was performed at 70 ° C. for 8 hours under a nitrogen gas environment. After the reaction, the solution was diluted with ethyl acetate (EtAc) so that the solid content concentration was 25% by mass, to obtain a solution of the base polymer (A).

On the other hand, 100 parts by mass of toluene was charged into a reaction vessel having a stirrer, a nitrogen introduction pipe, a thermometer, and a reflux cooling pipe, and the temperature was raised to 90 ° C while introducing nitrogen gas. Next, using a dropping funnel, 99 parts by mass of methyl methacrylate (MMA), 1 part by mass of dimethylamine ethyl methacrylate (DMAEMA), and 1 part by mass of azobisisobutyronitrile were dropped over 2 hours, and further added. 1 part by mass of azobisisobutyronitrile was polymerized for 5 hours while refluxing. After the reaction was completed, the solution was diluted with toluene so that the solid content concentration was 45% by mass, and a solution of a low molecular weight polymer (PMMA2) having a weight average molecular weight of 20,000 was obtained. Let this low molecular weight polymer (PMMA2) be (C-1).

100 parts by mass of the obtained base polymer (A) and 0.06 parts by mass of N, N, N ', N'-tetraepoxypropyl-m-xylene, which is an epoxy-based crosslinking agent, as the crosslinking agent (B) Diamine (MITSUBISHI GAS CHEMICAL COMPANY, INC .: TETRAD X) and 15 parts by mass of the aforementioned low molecular weight polymer (C-1) as a tackifier (tackifier) were mixed, and ethyl acetate was used. The ester was diluted and stirred so as to be a solution having a solid content concentration of 20%, and an adhesive composition was prepared (containing 15 parts by mass of PMMA2 as a tackifier with respect to 100 parts by mass of the base polymer (A)).

(Manufacturing Example 2) An adhesive composition was prepared in the same manner as in Production Example 1 except that no tackifier was used. PMMA2 ingredient).

(Production Example 3) An adhesive composition (relative to the base polymer) was prepared in the same manner as in Production Example 1 except that the blending amount of C-1 (PMMA2) was changed from 15 parts by mass to 10 parts by mass. (A) 100 parts by mass contains 10 parts by mass of a PMMA2 component as a tackifier).

(Production Example 4) An adhesive composition (relative to the base polymer) was prepared in the same manner as in Production Example 1 except that the blending amount of C-1 (PMMA2) was changed from 15 parts by mass to 25 parts by mass. (A) 100 parts by mass contains 25 parts by mass of a PMMA2 component as a tackifier).

(Production Example 5) An adhesive composition was prepared in the same manner as in Production Example 1 except that a low molecular weight polymer (denoted as C-2) having a weight average molecular weight of 1,000 was used as the tackifier (PMMA2).

(Production Example 6) An adhesive composition was prepared in the same manner as in Production Example 1 except that a low molecular weight polymer (denoted as C-3) having a weight average molecular weight of 45,000 was used as a tackifier (PMMA2). .

(Production Example 7) An adhesive composition was prepared in the same manner as in Production Example 1 except that a low molecular weight polymer (denoted as C-4) having a weight average molecular weight of 60,000 was used as a tackifier (PMMA2). .

(Example 1) A 100 μm-thick PET film (manufactured by Oji F-Tex Co., Ltd .: 100RL-07 (2)) was prepared as a separator. The adhesive composition obtained in Production Example 1 was applied to the separator so that the thickness after drying was 25 μm to form a coating film, and the coating film was dried at 100 ° C. for 3 minutes to harden the coating film and separate. An adhesive layer is formed on the piece. Next, a 75 μm-thick PMMA film (PARAPURE IT grade # 75 manufactured by KURARAY CO., LTD.) Made of PMMA1 was laminated on the surface of the adhesive layer as a substrate. Thereby, an adhesive sheet is obtained. The surface adhesiveness of the obtained adhesive sheet was evaluated, that is, evaluation of 3D decoration and reliability evaluation, weather resistance evaluation, water contact angle, and printability evaluation.

(Example 2) An adhesive sheet was obtained in the same manner as in Example 1 except that the adhesive composition obtained in Production Example 3 was used instead of the adhesive composition obtained in Production Example 1. The obtained adhesive sheet was evaluated in the same manner as in Example 1.

(Example 3) An adhesive sheet was obtained in the same manner as in Example 1 except that the adhesive composition obtained in Production Example 4 was used instead of the adhesive composition obtained in Production Example 1. The obtained adhesive sheet was evaluated in the same manner as in Example 1.

(Example 4) An adhesive sheet was obtained in the same manner as in Example 1, except that the adhesive composition obtained in Production Example 5 was used instead of the adhesive composition obtained in Production Example 1. The obtained adhesive sheet was evaluated in the same manner as in Example 1.

(Example 5) An adhesive sheet was obtained in the same manner as in Example 1 except that the adhesive composition obtained in Production Example 6 was used instead of the adhesive composition obtained in Production Example 1. The obtained adhesive sheet was evaluated in the same manner as in Example 1.

(Example 6) An adhesive sheet was obtained in the same manner as in Example 1 except that the adhesive composition obtained in Production Example 7 was used instead of the adhesive composition obtained in Production Example 1. The obtained adhesive sheet was evaluated in the same manner as in Example 1.

(Comparative Example 1) An adhesive sheet was obtained in the same manner as in Example 1 except that the substrate was changed to a PET film (manufactured by TOYOBO CO., LTD .: COMOSHINE A4300 # 75). The obtained adhesive sheet was evaluated in the same manner as in Example 1.

(Comparative Example 2) An adhesive sheet was obtained in the same manner as in Example 1 except that the adhesive composition obtained in Production Example 2 was used instead of the adhesive composition obtained in Production Example 1. The obtained adhesive sheet was evaluated in the same manner as in Example 1.

(Comparative example 3) Except having changed the base material into a PP film about the obtained adhesive sheet, it carried out similarly to Example 1, and obtained the adhesive sheet. The obtained adhesive sheet was evaluated in the same manner as in Example 1.

<Evaluation method> (Weight average molecular weight) As a GPC measurement device, a built-in high-temperature GPC measuring instrument "HLC-8121GPC-HT" made by TOSOH CORPORATION was used. -H (20) HT "connected to a GPC column, and the weight average molecular weight was measured. The column temperature was 140 ° C, trichlorobenzene was used as the eluent, and the measurement was performed at a flow rate of 1.0 ml / min. For the measurement, a calibration curve was prepared using standard polystyrene.

(Applicability of curved surface part) After peeling the separator, the pressure-sensitive adhesive sheet was vacuum-bonded at 140 ° C. to a glass (hereinafter referred to as 3D glass) having a curved surface part with R = 3.6. Thereafter, the laminated glass sample was left to stand at 23 ° C and 50 RH% for one hour, and the curved surface portion was observed, and the states of wrinkles, cracks, floating, peeling, and bubbles were determined by the following evaluation criteria. <Wrinkle> ◎: There is no film wrinkle on the 3D glass curved surface portion. ：: Although the wrinkles of the film on the curved surface portion of the 3D glass are enlarged, they cannot be confirmed visually. ×: The wrinkles of the film on the curved portion of the 3D glass can be visually confirmed. <Crack> ◎: There is no crack on the 3D glass curved surface. ：: Although cracks in the film on the curved portion of the 3D glass are enlarged, they cannot be confirmed visually. ×: Cracks in the film on the curved portion of the 3D glass can be visually confirmed. <Floating and peeling> ：: There was no floating or peeling at the interface between the film and the adhesive layer on the 3D glass curved portion. (Circle): Although it floats on the interface of a thin film and an adhesive layer on a 3D glass curved part, peeling and enlargement can be confirmed, but it cannot be confirmed visually. △: The surface of the 3D glass curved part was visually confirmed to be slightly floating and peeling at the interface between the film and the adhesive layer. ×: The surface of the 3D glass curved portion at the interface between the film and the adhesive layer can be visually confirmed to have floating and peeling. <Air bubbles> ：: There is no air bubble at the interface between the film and the adhesive layer on the 3D glass curved surface. ：: Although the bubbles at the interface between the film and the adhesive layer on the 3D glass curved portion are enlarged, they can be confirmed, but they cannot be confirmed visually. △: Some bubbles were visually confirmed at the interface between the film and the adhesive layer on the 3D glass curved portion. ×: Bubbles can be visually confirmed at the interface between the film and the adhesive layer on the 3D glass curved portion.

(Reliability) The laminated 3D glass sample was placed in a dry environment at 85 ° C for 100 hours, and the curved surface portion was observed thereafter. ：: The interface between the film and the adhesive layer on the curved surface portion of the 3D glass was completely free from floating / bubble and peeling. ○: The 3D glass curved portion floated at the interface between the film and the adhesive layer / bubbles and peeled and enlarged, although it can be confirmed, but it cannot be confirmed visually. △: The surface of the 3D glass curved part was visually confirmed to be slightly floating and peeling at the interface between the film and the adhesive layer. ×: The surface of the 3D glass curved portion at the interface between the film and the adhesive layer can be visually confirmed to have floating / bubbles and peeling.

(HAZE and transparency) The adhesive surface on one side of the adhesive sheets obtained in the examples and comparative examples was bonded to a glass slide (Part No .: S9112) made by Matsunami Glass Ind., Ltd. to make a sample, and to eliminate the sticking Due to the influence of fine air and the like mixed in at the same time, an autoclave (pressure defoaming) treatment was performed on the above-mentioned sample under the conditions of 0.5 MPa and 40 ° C for 30 minutes. Thereafter, the aforementioned sample was set on a NDH4000 manufactured by NIPPON DENSHOKU INDUSTRIES CO., LTD. So as to be a substrate, an adhesive layer, and glass in order from the light irradiation direction, and the haze was measured. When the measured HAZE value (%) is less than 1.5, the transparency is judged to be a pass, and when the measured HAZE value (%) is 1.5 or more, it is judged to be a fail. In particular, when the measured HAZE value is less than 1.0, the transparency is described as "◎", and when the measured HAZE value is 1.0 or more and less than 1.5, the transparency is described as "○", and the measured HAZE value is The transparency when it is 1.5 or more is marked as "×".

(Weather resistance) The adhesive surface on one side of the adhesive sheet obtained in the examples and comparative examples was bonded to a glass slide (Part No .: S9112) made by Matsunami Glass Ind., Ltd. to prepare a sample, and then to exclude the bonding The influence of the mixed fine air, etc., was performed on the aforementioned sample at a pressure of 0.5 MPa and 40 ° C. for 30 minutes in an autoclave (pressure defoaming) treatment. Thereafter, the aforementioned samples were set on a Sunshine / Xenon Weather Meter S80-X75 manufactured by Suga Test Instruments Co., Ltd. in order to sequentially form the substrate, the adhesive layer, and the glass as viewed from the light irradiation direction. Hours (processing conditions: BPT temperature = 63 ° C, irradiation amount: 162 [W / m ² ]), after that, the appearance of the sample taken out was observed and evaluated based on the following judgment criteria. (Double-circle): The 3D glass curved surface part did not float at the interface of a film and an adhesive layer, and there was no bubble or peeling. ○: The 3D glass curved surface part can be confirmed if it floats at the interface between the film and the adhesive layer, and bubbles and peeling are enlarged, but it cannot be confirmed visually. ×: The surface of the 3D glass curved surface portion can be visually confirmed to float and peel off at the interface between the film and the adhesive layer.

(Water contact angle) The adhesive sheets obtained in the examples and comparative examples were installed in Kyowa Interface Science Co. so that the substrate surface (the surface opposite to the adhesive layer) side faces the surface side and is parallel to the ground. LTD. Made of automatic contact angle meter DM-501. 0.2 μL of ion-exchanged water was dropped on the surface of the installed base material and left for 0.5 seconds. After that, the angle between the substrate and the dropped water droplets was measured.

(Printability) 100 parts by mass of an ink (trade name: MRX HF-919 black, manufactured by Teikoku Printing Inks Mfg. Co., Ltd.) and a hardener (trade name: 210 hardener, Teikoku Printing Inks Mfg. Co., Ltd. 5 parts by mass were mixed to prepare ink A.

In addition, 100 parts by mass of an ink (trade name: MRX HF-619 white, manufactured by Teikoku Printing Inks Mfg. Co., Ltd) and a hardener (trade name: 210 hardener, manufactured by Teikoku Printing Inks Mfg. Co., Ltd) 5 parts by mass were mixed to prepare ink B.

The substrate surface (the surface opposite to the adhesive layer) of the adhesive sheet obtained in the examples and comparative examples was screen-printed with ink A and ink B, respectively, and dried at 80 ° C. for 1 hour to the adhesive sheet. A 15 μm-thick printed layer was formed on the surface of the substrate. In accordance with JIS K 5600-5-6, the cross-cutting adhesion test was performed in the following manner.

A cellophane tape (trade name: CT28, manufactured by Nichiban Co., Ltd.) was adhered to the printed layer by pressing it with a finger from above, and then peeled off. The printed layer in 100 grids is 100/100 when all the squares are not peeled off, and the printed layer is 0/100 when all the squares are peeled off, and the squares in which the printed layer is not peeled off are calculated. The evaluation criteria evaluated the adhesion of the ink, and "◎" or "○" was taken as a level that could satisfy the printability. ◎: 96/100 ~ 100/100 ○: 75/100 ~ 95/100 ×: 0/100 ~ 74/100

[Table 1]

From the results shown in Table 1, it can be seen that the adhesive sheet obtained in the example is excellent in suitability for curved surface portions because the base material is PMMA1 and the adhesive layer contains PMMA2 as an adhesion promoter. In Example 6, PMMA2 has a large molecular weight, so although its transparency and reliability are inferior to those in Examples 1 to 5, the applicability of the curved surface portion is at a practically acceptable level. On the other hand, in Comparative Example 1, since the base material was PET instead of PMMA1, wrinkles and cracks were observed, and floating and peeling were also observed. Moreover, in Comparative Example 2, since PMMA was not contained as a tackifier, significant floating and peeling were observed. In Comparative Example 3, since the base material was PP instead of PMMA1, floating, peeling, and generation of bubbles were observed, and reliability, weather resistance, and printability were poor.

According to the above, the adhesive sheet of the present invention exhibits excellent adhesion, so that wrinkles and cracks are hard to occur after bonding, and floating and peeling are also difficult to occur.

1 (a) to (d) are schematic cross-sectional views each showing an example of an embodiment of the adhesive sheet for decoration molding according to the present invention.

Claims (5)

An adhesive sheet for decoration molding has a laminated body with a base material and an adhesive layer laminated on; the aforementioned substrate contains polymethyl methacrylate; and the aforementioned adhesive layer contains polymethyl methacrylate-containing tackifier. For example, the adhesive sheet for decoration molding of claim 1, wherein the weight average molecular weight (Mw) of the polymethyl methacrylate contained in the aforementioned tackifier is 500 to 50,000. The decorative sheet according to claim 1 or 2, wherein the aforementioned adhesive layer contains a crosslinked structure of a base polymer (A) other than polymethyl methacrylate; and The structural unit contains a (meth) acrylate monomer unit (a1) and a (meth) acrylic monomer unit (a2) having a crosslinkable functional group. The decorative sheet according to any one of claims 1 to 3, wherein the water contact angle of the surface of the aforementioned substrate opposite to the side of the adhesive layer is 40 ° to 95 °. In the adhesive sheet for decoration molding according to any one of claims 1 to 4, a separator is bonded to a surface of the adhesive layer opposite to the substrate side.