JP2017170866A - Pressure sensitive adhesive sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressure sensitive adhesive sheet having high productivity and weatherproofness.SOLUTION: A pressure sensitive adhesive sheet 1 includes a film layer 3, an adhesive layer 4 disposed on one side of the film layer 3, and a surface protective layer 2 disposed on the other side of the film layer 3. The film layer 3 has a sheet layer 3a and a resin layer 3c. At least one of the sheet layer 3a and the resin layer 3c contains a first ultraviolet light absorber. The adhesive layer 4 contains a second ultraviolet light absorber. The surface protective layer 2 contains a triazine-type ultraviolet light absorber as a third ultraviolet absorber. The surface protective layer 2 contains an acrylic resin with a hydrophobic functional group introduced therein. The pressure sensitive adhesive sheet 1 preferably includes an anchor coat layer 3b interposed between the sheet layer 3a and the resin layer 3c. In the pressure sensitive adhesive sheet 1, preferably, the layer facing the surface protective layer 2 contains the first ultraviolet light absorber and at least one layer not facing the surface protective layer 2 contains a fourth ultraviolet light absorber different from the first ultraviolet light absorber.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a pressure-sensitive adhesive sheet that can be bonded to an adherend.

2. Description of the Related Art Conventionally, a marking film that is used by being attached to the surface of a railway vehicle, an automobile, a vending machine or the like has been used. An overlay film for the purpose of surface protection, glossy factory, fading / deterioration prevention and the like may be attached to the surface of the marking film. Such an overlay film and a pressure-sensitive adhesive sheet used as a surface protecting film for an exterior signboard are required to have high weather resistance.
For example, in the following Patent Document 1 and Patent Document 2, a decorative sheet or a resin film is prepared by adding a weather stabilizer such as an ultraviolet absorber to the resin layer in order to achieve high weather resistance. It is described that a weathering stabilizer such as an ultraviolet absorber or a light stabilizer is added to the resin layer.

JP 2008-114560 A JP 2005-015557 A

However, when producing the above-mentioned pressure-sensitive adhesive sheet or the like, when forming a resin layer (resin film) as a base material, after extruding the molten resin to the carrier sheet and curing the resin to form the resin layer The carrier sheet is peeled off to obtain a resin film. For this reason, when producing an adhesive sheet etc., the manufacturing process of the resin layer may become complicated and productivity may fall.
The present invention has been made paying attention to the above-described points, and an object thereof is to provide a pressure-sensitive adhesive sheet having high productivity and weather resistance.

  In order to solve the problem, the pressure-sensitive adhesive sheet according to one embodiment of the present invention may not have sufficient weather resistance. The pressure-sensitive adhesive sheet according to one embodiment of the present invention includes a film layer, a pressure-sensitive adhesive layer formed on one surface of the film layer, and a surface protective layer formed on the other surface of the film layer. The film layer has a sheet layer, a resin layer, and an anchor coat layer interposed between the sheet layer and the resin layer, and at least the sheet layer, the resin layer, and the anchor coat layer One includes a first ultraviolet absorber, the pressure-sensitive adhesive layer includes a second ultraviolet absorber, and the surface protective layer includes a third ultraviolet absorber.

  According to one embodiment of the present invention, a pressure-sensitive adhesive sheet having high productivity and weather resistance can be obtained.

It is sectional drawing explaining the structure of the adhesive sheet which concerns on embodiment based on this invention. FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view schematically showing the pressure-sensitive adhesive sheet 1 according to this embodiment, and the relationship between the thickness and the planar dimensions, the ratio of the thickness of each layer, and the like are different from the actual ones. Further, the embodiment described below exemplifies a configuration for embodying the technical idea of the present invention, and the technical idea of the present invention is that the material, shape, structure, etc. of the component parts are as follows. It is not something specific. The technical idea of the present invention can be variously modified within the technical scope defined by the claims described in the claims.

As shown in FIG. 1, the pressure-sensitive adhesive sheet 1 of this embodiment includes a film layer 3, a pressure-sensitive adhesive layer 4 formed on one surface of the film layer 3, and the other surface of the film layer 3 (pressure-sensitive adhesive layer 4 And a surface protective layer 2 formed on a surface opposite to the formation surface.
Hereinafter, with reference to FIG. 1, each layer of the adhesive sheet 1 is demonstrated in detail.

<Film layer>
The film layer 3 is a laminated film formed of a resin material containing at least a first ultraviolet absorber for improving the weather resistance and laminated with a plurality of layers.
The film layer 3 may be transparent or opaque. The film layer 3 may be colored or uncolored. A light stabilizer may be added to the film layer 3 in order to prevent the resin material itself from being deteriorated by light, heat, water, or the like.

  As shown in FIG. 1, the film layer 3 includes a sheet layer 3a, a resin layer 3c, and an anchor coat layer 3b interposed between the sheet layer 3a and the resin layer 3c. That is, the film layer 3 includes a sheet layer 3a, an anchor coat layer 3b formed on the surface of the sheet layer 3a, and a resin layer 3b formed on a surface different from the surface opposite to the sheet layer 3a of the anchor coat layer 3b. It has a three-layer structure.

  Examples of the resin material constituting the resin layer 3c and the sheet layer 3a include polypropylene, polyethylene, polyethylene terephthalate, polyvinyl chloride, and the like, and thermoplastic resins such as mixtures, modified products, and polymers thereof. The resin layer 3c is formed, for example, by melting and extruding a resin material on the surface of the sheet layer 3a. The sheet layer 3a is a resin film in which a resin material is formed in a sheet shape in advance. Since the film layer 3 has a laminated structure including the sheet layer 3a and the resin layer 3c, a process of peeling the resin layer 3c from the sheet layer 3a to form a single layer structure is not necessary. For this reason, manufacture of the film layer 3 is easy and the productivity of the adhesion layer 1 improves.

In the film layer 3, it is preferable that the layer (resin layer 3c in the adhesive sheet 1 of FIG. 1) which opposes the surface protective layer 2 among the sheet layer 3a and the resin layer 3c contains a 1st ultraviolet absorber. The ultraviolet rays incident on the anchor coat layer 3b and the sheet layer 3c are obtained by including the first ultraviolet absorber in the resin layer 3c, which is the layer facing the surface protective layer 2 in the film layer 3 (layer on the ultraviolet incident side). Is suppressed, and deterioration of the anchor coat layer 3b and the sheet layer 3c is suppressed.
Moreover, the layer (sheet layer 3a in the adhesive sheet 1 of FIG. 1) which does not oppose the surface protective layer 2 among the sheet layer 3a and the resin layer 3c is a fourth ultraviolet absorber different from the first ultraviolet absorber. It is preferable to contain. When the film layer 3 as a whole contains two or more kinds of ultraviolet absorbers, the ultraviolet absorption effect is improved, and the weather resistance of the film layer 3 is improved.

In FIG. 1, the film layer 3 is disposed so that the sheet layer 3 a faces the adhesive layer 4 and the resin layer 3 c faces the surface protective layer 2, but the sheet layer 3 a faces the surface protective layer 2. And the film layer 3 may be arrange | positioned so that the resin layer 3c may oppose the adhesion layer 4. FIG. In this case, the layer facing the surface protective layer 2 is the sheet layer a, and at least the first ultraviolet absorber is added to the sheet layer a.
Moreover, when forming the resin layer 3c, when the molten resin which comprises the resin layer 3c fully adhere | attaches the sheet | seat layer 3a, the two-layer structure in which the anchor coat layer 3b is not provided may be sufficient.
Further, for example, in the film layer 3, a layer that does not face the surface protective layer 2 contains the first ultraviolet absorber, and a layer that faces the surface protective layer 2 contains an ultraviolet absorber different from the first ultraviolet absorber. It may be.

As a 1st ultraviolet absorber added to the film layer 3, the material which has an ultraviolet absorption wavelength range different from the ultraviolet absorption wavelength range of the 2nd ultraviolet absorber added to the adhesive layer 4 is mentioned. The 1st ultraviolet absorber added to the film layer 3 absorbs the ultraviolet-ray of a different wavelength range (wavelength range which is hard to be absorbed with the adhesive layer 4) from the 2nd ultraviolet absorber added to the adhesive layer 4. be able to.
The first ultraviolet absorber is preferably a material that absorbs ultraviolet rays having a wavelength longer than that of the second ultraviolet absorber. The first ultraviolet absorber preferably absorbs ultraviolet rays having a wavelength of 350 nm or more and 370 nm or less.

  As such a first ultraviolet absorber, for example, a benzotriazole ultraviolet absorber is preferably used. Examples of the benzotriazole ultraviolet absorber include 2- (2-hydroxy-5-tert-butylphenyl) -2H-benzotriazole, 2- (5-methyl-2-hydroxyphenyl) benzotriazole, 2- [2-hydroxy −3,5-bis (α, α-dimethylbenzyl) phenyl] -2H-benzotriazole, 2- (3,5-di-t-butyl-2-hydroxyphenyl) benzotriazole, 2- (3-t- Butyl-5-methyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 2- (3,5-di-t-butyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 2- (3,5- Di-t-amyl-2-hydroxyphenyl) benzotriazole, 2- (2′-hydroxy-5′-octylphenyl) benzotriazole And mixtures thereof, modified products, polymers, and derivatives.

  The number of added parts of the first ultraviolet absorber is 0.1% by mass or more and 50% by mass or less, preferably 0.5% by mass or more and 30% by mass or less with respect to the resin material that is the material of the film layer 3. This is because the ultraviolet absorbing effect is sufficiently exhibited and bleeding out of the ultraviolet absorbent can be suppressed.

As a 2nd ultraviolet absorber added to the film layer 3, the material etc. which have an ultraviolet absorption wavelength range different from the ultraviolet absorption wavelength range of the above-mentioned 1st ultraviolet absorber are mentioned. For example, in the pressure-sensitive adhesive sheet 1 shown in FIG. 1, the second ultraviolet absorber added to the sheet layer 3 a of the film layer 3 is different in wavelength range from the first ultraviolet absorber added to the resin layer 3 c of the film layer 3. It is possible to absorb ultraviolet rays (wavelength region that is difficult to be absorbed by the resin layer 3c of the film layer 3).
The second ultraviolet absorber is preferably a material that absorbs ultraviolet rays having a shorter wavelength than the first ultraviolet absorber. The second ultraviolet absorber preferably absorbs ultraviolet rays having a wavelength of at least 310 nm and not more than 350 nm.

  As such a second ultraviolet absorber, for example, a triazine-based ultraviolet absorber is preferably used. Examples of the triazine ultraviolet absorber include 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5-[(hexyl) oxy] -phenol, 2- [4-[(2- Hydroxy-3-dodecyloxypropyl) oxy] -2-hydroxyphenyl] -4,6-bis (2,4-dimethylphenyl) -1,3,5-triazine, 2- [4-[(2-hydroxy- 3-tridecyloxypropyl) oxy] -2-hydroxyphenyl] -4,6-bis (2,4-dimethylphenyl) -1,3,5-triazine, 2,4-bis (2,4-dimethylphenyl) ) -6- (2-hydroxy-4-iso-octyloxyphenyl) -s-triazine, mixtures thereof, modified products, polymers, derivatives, and the like.

  The number of added parts of the second ultraviolet absorber is 0.1 mass% or more and 50 mass% or less, preferably 0.5 mass% or more and 30 mass% or less with respect to the resin material of the layer to which the second ultraviolet absorber is added. It is. This is because the ultraviolet absorbing effect is sufficiently exhibited and bleeding out of the ultraviolet absorbent can be suppressed.

Further, as the light stabilizer added to the film layer 3, a hindered amine light stabilizer is preferably used.
As the hindered amine light stabilizer, bis (1,2,2,6,6-pentamethyl-4-piperidinyl) [[3,5-bis (1,1-dimethylethyl) -4-hydroxyphenyl] methyl] butyl Malonate, bis (1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate, methyl (1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate, bis [2,2] decanoic acid 2,6,6-tetramethyl-1-octyloxy) -4-piperidinyl] ester and the like, mixtures thereof, modified products, polymers, derivatives and the like.

The film layer 3 can be formed to have a desired thickness. For example, the thickness is preferably 80 μm or more and 120 μm or less. This is because the adhesive film 1 has particularly high strength and weather resistance, and the productivity at the time of manufacturing the film layer 3 is better.
The thickness of the sheet layer 3a of the film layer 3 is preferably 19 μm or more and 30 μm or less. This is because the strength necessary for the carrier sheet used when the resin layer 3c is formed is obtained, and sufficient weather resistance is obtained.
The thickness of the resin layer 3c of the film layer 3 is preferably 60 μm or more and 85 μm or less. This is because sufficient weather resistance can be obtained as a base material layer constituting the film layer 3.
The thickness of the anchor coat layer 3b of the film layer 3 is preferably 1 μm or more and 5 μm or less. The productivity of the film layer 3 is improved because the thickness of the film layer 3 is not excessively increased while sufficiently increasing the adhesion between the sheet layer 3a and the resin layer 3c.
Such a film layer 3 has a light transmittance of 0.5% or less. Therefore, deterioration of the film layer 3 due to ultraviolet rays can be suppressed.

<Adhesive layer>
The pressure-sensitive adhesive layer 4 is formed of an adhesive containing a second ultraviolet absorber for improving weather resistance. Further, a light stabilizer may be added to the pressure-sensitive adhesive layer 4 in order to prevent the adhesive itself from being deteriorated by light, heat, water or the like. Examples of the adhesive include acrylic adhesives, rubber adhesives, epoxy adhesives, and isocyanate adhesives, but acrylic adhesives are preferably used.

  Examples of the acrylic adhesive include n-butyl (meth) acrylate, hexyl (meth) acrylate, 2-diethylbutyl (meth) acrylate, isooctyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, (Meth) acrylic acid 2-ethylhexyl, (meth) acrylic acid decyl, (meth) acrylic acid dodecyl, (meth) acrylic acid tridecyl ester, etc. (Meth) acrylic acid, itaconic acid, maleic acid, maleic anhydride, hydroxyethyl acrylate, hydroxypropyl acrylate, acrylamide, dimethylacrylamide, methylaminoethyl methacrylate, (meth) acrylic acid, copolymerizable with acrylic ester Copolymers with functional monomers such as methoxyethyl And the like.

Examples of the rubber-based adhesive include natural rubber-based, isoprene rubber-based, styrene-butadiene-based, recycled rubber-based, polyisobutylene-based, and blocks including rubbers such as styrene-isoprene-styrene and styrene-butadiene-styrene. Examples thereof include an adhesive mainly comprising a copolymer.
Examples of the epoxy adhesive include aliphatic chain-modified epoxy resins, hydrocarbon-modified epoxy resins such as cyclopentadiene-modified epoxy resins and naphthalene-modified epoxy resins, elastomer-modified epoxy resins, and silicone-modified epoxy resins.
Examples of the isocyanate-based adhesive include caprolactam-based blocked isocyanate, phenol-based blocked isocyanate, and toluene diisocyanate-based.

  As the above-mentioned adhesive, any of non-crosslinked type and crosslinked type can be used. In the latter case, a crosslinking agent can be added as necessary. As the crosslinking agent, for example, an epoxy compound, an isocyanate compound, a metal chelate compound, a metal alkoxide, a metal salt, an amine compound, a hydrazine compound, an aldehyde compound, or the like can be used alone or in admixture of two or more. .

Examples of the second ultraviolet absorber added to the pressure-sensitive adhesive layer 4 include a material having an ultraviolet absorption wavelength region different from the ultraviolet absorption wavelength region of the first ultraviolet absorber added to at least one layer of the film layer 3. Is mentioned. The second ultraviolet absorber added to the pressure-sensitive adhesive layer 4 absorbs ultraviolet rays in a wavelength region different from that of the first ultraviolet absorber added to the film layer 3 (wavelength region difficult to be absorbed by the film layer 3). Can do.
The second ultraviolet absorber is preferably a material that absorbs ultraviolet rays having a shorter wavelength than the first ultraviolet absorber. The second ultraviolet absorber preferably absorbs ultraviolet rays having a wavelength of at least 310 nm and not more than 350 nm.

As such a second ultraviolet absorber, for example, a triazine ultraviolet absorber similar to the fourth ultraviolet absorber is preferably used.
The added number of the second ultraviolet absorber is 0.1% by mass or more and 50% by mass or less, and preferably 0.5% by mass or more and 30% by mass or less with respect to the adhesive which is the material of the pressure-sensitive adhesive layer 4. This is because the ultraviolet absorbing effect is sufficiently exhibited and bleeding out of the ultraviolet absorbent can be suppressed.

  Further, as the light stabilizer added to the pressure-sensitive adhesive layer 4, it is preferable to use the same hindered amine light stabilizer as the light stabilizer added to the film layer 3.

The pressure-sensitive adhesive layer 4 can be formed to a desired thickness, and for example, the thickness is preferably 20 μm or more and 40 μm or less. This is because the pressure-sensitive adhesive film 1 has higher strength and weather resistance, and the productivity during production of the pressure-sensitive adhesive layer 4 is better.
Such an adhesive layer 4 has a light transmittance of 0.5% or less in an ultraviolet region having a wavelength region of 310 nm or more and 370 nm or less. Therefore, deterioration of the film layer 3 due to ultraviolet rays can be suppressed.

<Surface protective layer>
The surface protective layer 2 is formed of a resin material such as a thermoplastic resin containing a third ultraviolet absorber for improving weather resistance. The surface protective layer 2 is a layer transparent to the extent that the film layer 3 can be visually recognized.
The thermoplastic resin used for the surface protective layer 2 is selected in consideration of water resistance and adhesion between the surface protective layer 2 and the film layer 3, and is an acrylic resin having a hydrophobic functional group introduced therein, particularly a hydrophobic functional group. Including acrylic urethane resin. The acrylic urethane resin introduced with a hydrophobic functional group in the present embodiment is obtained by polymerizing monomers having many hydrophobic functional groups. Further, the surface protective layer 2 may contain other thermoplastic resin together with the acrylic urethane resin into which the hydrophobic functional group is introduced. Examples of other thermoplastic resins include polyolefin resins such as polypropylene and polyethylene, mixtures thereof, modified products, and polymers. When the surface protective layer 2 contains an acrylic resin having a hydrophobic functional group introduced therein (an acrylic urethane resin having a hydrophobic functional group introduced), the water resistance of the surface protective layer 2 is sufficiently increased. The thickness can be reduced. For this reason, the amount of resin material used (the amount of molten resin applied) can be reduced, and the surface protective layer 2 can be easily formed. Moreover, while suppressing the discoloration and fading of the surface protective layer 2 by being exposed to moisture when using the pressure-sensitive adhesive sheet 1, it contributes to the improvement of weather resistance. In addition, a light stabilizer may be added to the surface protective layer 2.

  As the third ultraviolet absorber added to the surface protective layer 2, for example, a triazine-based ultraviolet absorber similar to the fourth ultraviolet absorber is used. In the pressure-sensitive adhesive sheet 1, the surface protective layer 2 contains a triazine-based ultraviolet absorber, so that the surface protective layer 2 that first receives ultraviolet rays efficiently absorbs ultraviolet rays, and the amount of ultraviolet rays received by the film layer 3 and the adhesive layer 4 is reduced. Can be reduced. For this reason, stability of the film layer 3 and the adhesion layer 4 improves dramatically, and the weather resistance of the adhesive sheet 1 improves. The third ultraviolet absorber is a material that absorbs ultraviolet rays having a wavelength different from that of the first ultraviolet absorber. Specifically, the third ultraviolet absorber is a material that absorbs ultraviolet rays having a shorter wavelength than the first ultraviolet absorber. Therefore, a wide range of ultraviolet rays can be absorbed by the film layer 3 containing the first ultraviolet absorber and the surface protective layer 2 containing the third ultraviolet absorber.

The number of added parts of the third ultraviolet absorber is 0.05% by mass or more and 30% by mass or less, preferably 0 with respect to the resin material including the acrylic urethane resin into which the hydrophobic functional group that is the material of the surface protective layer 3 is introduced. 0.05 mass% or more and 25 mass% or less. This is because the ultraviolet absorbing effect is sufficiently exhibited and bleeding out of the ultraviolet absorbent can be suppressed. When a triazine-based ultraviolet absorber is used as the third ultraviolet absorber, the number of added ultraviolet absorbers can be reduced as compared with the case where a benzotriazole-based ultraviolet absorber is used. For this reason, it becomes easy to mix a 3rd ultraviolet absorber with the acrylic urethane resin which introduce | transduced the hydrophobic functional group, and the productivity of an adhesive sheet improves. Moreover, since the addition property of the 3rd ultraviolet absorber with respect to the acrylic urethane resin which introduce | transduced the hydrophobic functional group improves, the quality of the surface protective layer 2 improves and the stability of the adhesive sheet 1 improves. Moreover, when using a triazine type ultraviolet absorber as a 3rd ultraviolet absorber, the surface protection layer 2 can be made thin compared with the case where the benzotriazole type ultraviolet absorber of the same amount addition part is used. For this reason, since formation of the surface protective layer 2 becomes easy and manufacturing time is shortened, productivity of the pressure-sensitive adhesive sheet is improved.
Further, as the light stabilizer added to the surface protective layer 2, it is preferable to use the same hindered amine light stabilizer as the light stabilizer added to the film layer 3.

  The surface protective layer 2 can be formed to a desired thickness, and for example, the thickness is preferably 6 μm to 15 μm. When the thickness of the surface protective layer 2 is in the above range, the weather resistance and water resistance of the pressure-sensitive adhesive sheet 1 are sufficiently high, and the surface protective layer 2 is not too thick. Is prevented and blocking is prevented. Thereby, the fall of the production speed at the time of adhesive sheet manufacture and the fall of a yield can be suppressed, and the productivity of the adhesive sheet 1 can be improved.

<Effect>
The adhesive layer according to the present embodiment as described above has the following effects.
(1) By making the film layer of an adhesive sheet into the laminated structure containing a resin layer and a sheet layer, the process of peeling a resin layer from a sheet layer and making it a single layer structure becomes unnecessary. For this reason, manufacture of a film layer is easy and productivity of an adhesion layer improves.
(2) Since the surface protective layer contains a triazine-based ultraviolet absorber as an ultraviolet absorber, the surface protective layer that receives ultraviolet rays efficiently absorbs ultraviolet rays and reduces the amount of ultraviolet rays received by the film layer and the adhesive layer. can do. For this reason, stability of a film layer or an adhesion layer improves dramatically, and the weather resistance of an adhesive sheet improves.
(3) Since the surface protective layer contains an acrylic resin having an introduced hydrophobic functional group (an acrylic resin having an introduced hydrophobic functional group), the surface protective layer has sufficiently high water resistance and improved weather resistance. Contribute to.

(4) The discoloration of the surface protective layer due to the surface protective layer being exposed to moisture during use of the pressure-sensitive adhesive sheet is suppressed.
(5) By adding an ultraviolet absorber to each of the film layer, the pressure-sensitive adhesive layer and the surface protective layer, the absorption wavelength of ultraviolet rays can be made different in each layer, and ultraviolet rays in a wavelength region that are difficult to be absorbed by any layer Can be absorbed by other layers. That is, each layer can mutually compensate for the ultraviolet absorption wavelength.
(6) Not only one layer (for example, the surface protective layer) but also other layers (for example, the film layer and the pressure-sensitive adhesive layer) are added with an ultraviolet absorber to suppress bleeding out of the ultraviolet absorber. Connected.
(7) Adhesion between the resin layer and the sheet layer can be improved by providing an anchor coat layer between the sheet layer and the resin layer.

(8) Of the sheet layer and the resin layer, the layer facing the surface protective layer (the layer on the ultraviolet incident side) contains the first ultraviolet absorber, thereby suppressing the ultraviolet rays incident on the anchor coat layer and the sheet layer. Thus, deterioration of the anchor coat layer and the sheet layer is suppressed.
(9) When at least one of the layers not opposed to the surface protective layer contains a fourth ultraviolet absorber different from the first ultraviolet absorber, the film layer as a whole contains two or more types of ultraviolet absorbers, and ultraviolet rays As a result, the weather resistance of the film layer is improved.
(10) When the thickness of the film layer is 80 μm or more and 120 μm or less, the pressure-sensitive adhesive film has particularly high strength and weather resistance, and the productivity during production of the film layer becomes good.
(11) Since the thickness of the surface protective layer can be reduced, the amount of resin material used (the amount of molten resin applied) can be reduced, and the surface protective layer can be easily formed.

(12) Since the ultraviolet absorption wavelength region of the first ultraviolet absorber is different from the ultraviolet absorption wavelength region of the second ultraviolet absorber, the film layer and the pressure-sensitive adhesive layer can supplement the ultraviolet absorption wavelength. .
(13) The third ultraviolet absorber overlaps with both the ultraviolet absorption wavelength region of the first ultraviolet absorber and the ultraviolet absorption wavelength region of the second ultraviolet absorber. Thereby, in the surface protective layer that is likely to be an ultraviolet incident surface of the pressure-sensitive adhesive sheet, ultraviolet rays having a wide range of wavelengths can be absorbed, and the ultraviolet rays incident on the film layer and the pressure-sensitive adhesive layer can be reduced. Thereby, deterioration of the film layer and the pressure-sensitive adhesive layer is further suppressed, the pressure-sensitive adhesive layer is deteriorated and peeled off from the adherend such as an outer wall or a window, or the film layer and the pressure-sensitive adhesive layer are deteriorated due to deterioration of at least one of Peeling of the pressure-sensitive adhesive layer can be further prevented.
(14) When a film contains a thermoplastic resin, deterioration of the adhesive sheet when an outer wall, a window, etc. become high temperature is suppressed.

Hereinafter, the adhesive sheet in the present embodiment will be described with specific examples and comparative examples. In addition, this embodiment is not restrict | limited by the following examples and comparative examples. <Example 1>
(Formation of film)
A melted polypropylene resin (Prime Polymer Co., Ltd., Prime TPO F-3900 (registered trademark)) is mixed with a benzotriazole-based UV absorber and a hindered amine-based light stabilizer that absorb at least 350 nm to 370 nm UV light. did. Subsequently, an extruded resin layer was formed on the polypropylene sheet serving as a carrier film having a thickness of 80 μm and a thickness of 30 μm by using an extruder with the molten resin kneaded with the above-described ultraviolet absorber and light stabilizer. At this time, an anchor coat layer was formed on a resin layer forming surface of a polypropylene sheet (hereinafter referred to as a sheet layer), and the sheet layer and the resin layer were formed via the anchor coat layer. The anchor coat layer was formed by applying and drying a two-component urethane resin adhesive having polyester polyol as a main component and isophorone diisocyanate as a curing agent to a thickness of 2 μm. Thus, a transparent film (hereinafter referred to as a transparent film) in which a resin layer having a thickness of 80 μm, an anchor coat layer having a thickness of 2 μm, and a sheet layer having a thickness of 30 μm was laminated was formed.

(Formation of adhesive layer)
A triazine-based ultraviolet absorber that absorbs ultraviolet rays on a shorter wavelength side, which is different from the benzotriazole-based ultraviolet absorber added to the transparent film, in a two-component cross-linking acrylic adhesive (Arivine BPS 6316, manufactured by Toyo Ink Co., Ltd.) And a hindered amine light stabilizer was added and kneaded. Subsequently, the acrylic adhesive kneaded with the above-described ultraviolet absorber and light stabilizer is dried on the other surface of the transparent film (a surface different from the surface protective layer forming surface) to a thickness of 30 μm. The coating amount was adjusted to be applied. Finally, the coated acrylic adhesive was dried to form an adhesive layer having a thickness of 30 μm.

(Formation of surface protective layer)
A triazine-based ultraviolet absorber that absorbs ultraviolet rays having the same wavelength as that of the triazine-based ultraviolet absorber added to the adhesive layer in a molten thermosetting hydrophobic functional group-introduced acrylic urethane resin (manufactured by DIC Graphics). A hindered amine light stabilizer was added and melt kneaded. The triazine-based ultraviolet absorber was added in an amount of 20% by mass relative to the acrylic urethane resin having a hydrophobic functional group introduced. Subsequently, the acrylic urethane resin introduced with the hydrophobic functional group kneaded with the above-described ultraviolet absorber and light stabilizer is applied on one surface of the transparent film so that the thickness after curing is 6 μm. The coating was adjusted. Finally, the coated acrylic functional group-introduced acrylic urethane resin was cured to form a 6 μm thick surface protective layer.
By the above, the adhesive sheet in which the surface protection layer and the adhesion layer were formed on both surfaces of the transparent film was produced.

<Comparative Example 1>
A transparent film as a film layer was formed as follows.
The same benzotriazole ultraviolet absorber and hindered amine light stabilizer as in Example 1 were added to a molten polypropylene resin (Prime TPO F-3900 (registered trademark), manufactured by Prime Polymer Co., Ltd.) and kneaded. Subsequently, an extruded resin layer was formed on the polypropylene sheet serving as a carrier film having a thickness of 80 μm and a thickness of 30 μm by using an extruder with the molten resin kneaded with the above-described ultraviolet absorber and light stabilizer. At this time, the anchor coat layer was not formed on the resin layer forming surface of the polypropylene sheet. Finally, a transparent film made of a resin layer having a thickness of 80 μm was formed by peeling the resin layer from the polypropylene sheet.
Except this, it carried out similarly to Example 1, and produced the adhesive sheet in which the surface protective layer and the adhesion layer were each formed on both surfaces of the transparent film.

[Evaluation]
The pressure-sensitive adhesive sheets of Example 1 and Comparative Example 1 described above were evaluated as follows.

(Accelerated weather resistance test)
The accelerated weather resistance test was performed on the pressure-sensitive adhesive sheets of each Example and each Comparative Example under the following conditions, and the surface of each pressure-sensitive adhesive sheet was confirmed for cracks / cracks.

(conditions)
Testing machine: Metal weather testing machine (Daipura Metal Weather KU-R5DC1-A manufactured by Daipura Wintes Co., Ltd.)
Condition: Illuminance 65 mW / cm ² , Light (53 ° C., 50% RH) 20 hours, Dew (30 ° C., 95% RH) 4 hours Watering condition: 30 s before and after Dew
The above process was made into 1 cycle, and the accelerated weather resistance test was implemented with respect to each adhesive sheet of an Example and a comparative example for 144 hours.
After the test, the surface of the adhesive sheet was checked for cracks / cracks.

  In the accelerated weather resistance test, regarding the cracks / cracks on the surface of the pressure-sensitive adhesive sheet, “◎” indicates that no cracks or cracks were generated on the surface, and “○” indicates that cracks or cracks were generated. The case where occurrence occurred was evaluated as “×”.

(Evaluation of productivity of adhesive sheet)
Productivity was evaluated about the adhesive sheet of each Example and each comparative example.
When evaluating productivity, “◎” indicates that productivity is very good, “△” indicates that productivity is inferior, and productivity is greatly inferior (for example, production of an adhesive sheet is impossible). Was marked “x”.

  Table 1 below shows the configurations of Examples and Comparative Examples. The evaluation results are shown in Table 2 below.

(Discussion)
As can be seen from Table 1, the productivity of the pressure-sensitive adhesive sheet of Example 1 using the carrier sheet as the sheet layer of the film layer when forming a film layer (transparent film) was significantly improved as compared with the pressure-sensitive adhesive sheet of Comparative Example 1. . This is considered to be because the manufacturing time of the pressure-sensitive adhesive sheet was shortened because the step of peeling the resin layer from the carrier sheet as in Comparative Example 1 was unnecessary.
Moreover, the weather resistance improved the adhesive sheet of Example 1 compared with the adhesive sheet of the comparative example 1. This is considered to be because the film layer was thicker than the pressure-sensitive adhesive sheet of Comparative Example 1 and the stability as the pressure-sensitive adhesive sheet was improved. Moreover, in the film layer of the adhesive sheet of Example 1, since the ultraviolet absorber is added to the layer facing the surface protective layer among the plurality of layers, the influence of ultraviolet rays on the layer not facing the surface protective layer is affected. It is considered that the weather resistance is improved.

  As described above, in the pressure-sensitive adhesive sheet of the present embodiment, as in Example 1, the film layer has the sheet layer and the resin layer, and at least one of the sheet layer and the resin layer contains the ultraviolet absorber. Moreover, it is preferable that the adhesive sheet of this embodiment has an anchor coat layer interposed between the sheet layer and the resin layer as in Example 1. In the pressure-sensitive adhesive sheet of this embodiment, as in Example 1, the layer facing the surface protective layer of the film layer having a laminated structure preferably contains an ultraviolet absorber.

[Others]
The scope of the present invention is not limited to the illustrated and described exemplary embodiments, but also includes all embodiments that provide equivalent effects to those intended by the present invention. Further, the scope of the invention is not limited to the combinations of features of the invention defined by the claims, but can be defined by any desired combination of specific features among all the disclosed features.

DESCRIPTION OF SYMBOLS 1 Adhesive sheet 2 Surface protective layer 3 Film layer 3a Sheet layer 3b Anchor coat layer 3c Resin layer 4 Adhesive layer

Claims (10)

A film layer;
An adhesive layer formed on one surface of the film layer;
A surface protective layer formed on the other surface of the film layer;
With
The film layer has a sheet layer and a resin layer, and at least one of the sheet layer and the resin layer contains a first ultraviolet absorber,
The pressure-sensitive adhesive layer contains a second ultraviolet absorber,
The pressure-sensitive adhesive sheet, wherein the surface protective layer contains a triazine-based ultraviolet absorber as a third ultraviolet absorber.   The pressure-sensitive adhesive sheet according to claim 1, wherein the surface protective layer contains an acrylic urethane resin into which a hydrophobic functional group is introduced.   The pressure-sensitive adhesive sheet according to claim 1, further comprising an anchor coat layer interposed between the sheet layer and the resin layer.   The pressure sensitive adhesive sheet according to any one of claims 1 to 3, wherein a layer facing the surface protective layer among the sheet layer and the resin layer contains a first ultraviolet absorber.   5. The pressure-sensitive adhesive sheet according to claim 4, wherein at least one of the layers not opposed to the surface protective layer contains a fourth ultraviolet absorbent different from the first ultraviolet absorbent.   The pressure-sensitive adhesive sheet according to any one of claims 1 to 4, wherein a thickness of the film layer is 80 µm or more and 120 µm or less.   The pressure-sensitive adhesive sheet according to any one of claims 1 to 6, wherein the surface protective layer has a thickness of 6 µm or more and 15 µm or less.   The pressure-sensitive adhesive sheet according to any one of claims 1 to 7, wherein an ultraviolet absorption wavelength region of the first ultraviolet absorber is different from an ultraviolet absorption wavelength region of the second ultraviolet absorber.   The pressure-sensitive adhesive sheet according to claim 8, wherein the first ultraviolet absorber absorbs ultraviolet rays having a longer wavelength than the second ultraviolet absorber. The third ultraviolet absorber has an ultraviolet absorption wavelength region that overlaps with both the ultraviolet absorption wavelength region of the first ultraviolet absorber and the ultraviolet absorption wavelength region of the second ultraviolet absorber. The pressure-sensitive adhesive sheet according to any one of claims 1 to 9.

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