JP2001011406A - Pressure-sensitive adhesive sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressure-sensitive adhesive sheet using a film as a surface base material, in particular containing a polypropylene film as a substrate, has a good printability excellent in a conventional-printing aptitude such as a gravure printing, a relief printing and an offset printing as well as excellent in a UV flexographic printing aptitude, thus is suitable for an indication label. SOLUTION: A pressure-sensitive adhesive sheet is a laminate of a surface base material, a pressure-sensitive adhesive layer and a release sheet, the surface base material being a substrate film which contains a synthetic polymer and has an easy printable layer on at least one surface with no pressure-sensitive adhesive, with the easy printable layer having an arithmetic surface roughness Ra according to JIS B 0601 of 0.2-3.5 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure-sensitive adhesive sheet using a film as a surface substrate, and more particularly, to a gravure printing method including a polypropylene film as a substrate.
The present invention relates to a pressure-sensitive adhesive sheet which is excellent in printability in the past such as letterpress printing and offset printing and also excellent in UV flexographic printing, has good printability, and is suitable for a display label.

[0002]

2. Description of the Related Art Conventionally, pressure-sensitive adhesive sheets have been used for commercial, office,
It is widely used in the form of labels, stickers, stickers, patches, delivery slips, etc., for process management, logistics management, home use, etc. One use of the pressure-sensitive adhesive sheet is as a label for a container to be attached to a transparent or colored container. Paper, polyvinyl chloride film, synthetic paper, polyethylene terephthalate (PET), vapor-deposited PET and the like are used as the surface base material of the display label.

[0003] As a printing method of these display labels, letterpress printing is mainly used, and offset printing, screen printing and the like are employed. However, the use of flexographic inks in UV has recently made it possible to increase the viscosity and concentration of UV inks.
Since laser engraving of 0 to 1200 lines has become possible and process printing with gradation has been made possible, UV flexographic printing has begun to be used because solid printing can be printed finely.

[0004] With the recent improvement in UV flexographic printing technology, the substrate film to be printed is required to have higher quality. In particular, there is no problem with ink adhesion in the conventional seal printing system. Even the film that was supposed to be
The change in flexographic ink and / or printing method causes a problem of poor ink adhesion.

[0005]

DISCLOSURE OF THE INVENTION The present invention relates to a display label having a printable transparent film as a surface substrate, which is used as a label for a transparent container or the like, and is excellent only in printability of a conventional printing method. In addition, the present invention relates to a good pressure-sensitive adhesive sheet having excellent ink adhesion, excellent transparency, and little discoloration due to light even in UV flexographic printing.

[0006]

Means for Solving the Invention (1) In a pressure-sensitive adhesive sheet in which a surface substrate, a pressure-sensitive adhesive layer, and a release sheet are laminated,
The surface substrate is a base film containing a synthetic polymer, and at least the surface of the base film on which the pressure-sensitive adhesive layer is not formed has an easy print layer containing a binder resin, and
Arithmetic surface roughness Ra according to ISB0601 is 0.2 to
It is a 3.5-μm pressure-sensitive adhesive sheet having good printability. The base film is preferably one selected from a polyethylene film, a polypropylene film, a polystyrene film, a polyvinyl alcohol film, a polyester film, and a polycarbonate film.

(2) The pressure-sensitive adhesive sheet according to (1), wherein the binder resin for the easy printing layer contains at least one polymer containing an ester bond (—CO—O—). (3) the ester bond-containing polymer is at least one polymer and copolymer selected from acrylic acid, methacrylic acid, acrylate and methacrylate, a polyester resin, an ethylene-vinyl acetate copolymer, The pressure-sensitive adhesive sheet according to (2), which is selected from a vinyl chloride-vinyl acetate copolymer. (4) The binder resin has a glass transition temperature of −20 to 20 ° C. and at least one ester bond-containing polymer (a), and at least one ester bond having a glass transition temperature of 40 to 80 ° C. The pressure-sensitive adhesive sheet according to (2), which is selected from a mixture with the polymer (b).

(5) The average particle diameter of 1 to 10
The pressure-sensitive adhesive sheet according to any one of (1) to (4), wherein the pressure-sensitive adhesive sheet contains a μm pigment. The pigment is preferably an organic pigment or an inorganic pigment having a spherical particle shape, and preferably contains 0.1 to 2% by weight based on the total weight of the easily printable layer.

(6) The pressure-sensitive adhesive sheet according to any one of (1) to (5), wherein the surface substrate has an anchor layer containing an adhesive resin formed between the substrate film and the easily printed layer. . (7) The pressure-sensitive adhesive sheet according to (6), wherein the adhesive resin for an anchor layer includes at least one selected from an isocyanate compound, a resin having an oxazoline group, and a resin having an ethylimine group.

(8) The method according to any one of (1) to (7), wherein an easy-adhesion layer containing an easily-adhesive resin is formed between the base film and the easy print layer or between the base film and the anchor layer. It is an adhesive sheet. (9) The pressure-sensitive adhesive sheet according to any one of (1) to (8), wherein the pressure-sensitive adhesive layer is an acrylic resin layer containing an acrylate copolymer as a main component.

(10) The haze of the constitution of the pressure-sensitive adhesive layer and the surface substrate from which the release sheet of the pressure-sensitive adhesive sheet has been peeled off is 1.0 to 1.0.
The pressure-sensitive adhesive sheet according to any one of (1) to (9), wherein the content is 6.0%. (11) The release sheet of the pressure-sensitive adhesive sheet is peeled off, attached to a transparent substrate, and irradiated with ultraviolet light (295 to 400 nm) from the transparent substrate surface.
Was irradiated at 7.2 MJ / m ² , and L ^* a ^* b before and after the irradiation.
^* The pressure-sensitive adhesive sheet according to any one of (1) to (10), wherein ΔE ^* determined from (CIELAB) is 1.0 or less.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION As the base film of the surface substrate constituting the pressure-sensitive adhesive sheet of the present invention, a polyethylene film, a polypropylene film, a polystyrene film,
It can be selected from a polyvinyl alcohol film, a polyester film (for example, a polyethylene terephthalate film), a polycarbonate film, and the like. Among them, a film subjected to a secondary stretching treatment is preferable, and it is particularly preferable to use a biaxially stretched polypropylene film which is inexpensive, has excellent transparency, and has excellent workability. The thickness of the base film can be appropriately selected depending on the application, but is about 20 to 200 μm, preferably about 20 to 100 μm for a display label.

The polypropylene referred to in the present invention is a polypropylene composition mainly composed of polypropylene, a polypropylene copolymer or a mixture thereof. Not only a homopolymer of polypropylene, but also ethylene, butene, 4-methylpentene, etc. A copolymer of propylene with a monomer copolymerizable with propylene such as α-olefins represented by, aromatic olefins represented by styrene, dienes represented by butadiene, or polypropylene or polypropylene copolymer Known blends of the coalesced with these, such as polyethylene, poly-α-olefins such as various ethylene copolymers, polystyrene, synthetic rubber, terpene resin, polyamide, polyester, polyether, etc. Or a mixture of these The type and amount of the copolymer component of the polypropylene copolymer or the blend component of the blend composition may be any as long as the characteristics of the polypropylene film are not lost.

The method for producing the substrate film of the present invention is not particularly limited. For example, as a method for producing a polypropylene film, the polypropylene composition may be melt-extruded according to a conventional method and then longitudinally stretched, or may be horizontally stretched, or may be vertically stretched after transverse stretching. . The longitudinal and transverse stretching ratios are each 2 times or more.
Preferably it is 20 times. A desired surface of the obtained biaxially stretched film, or both surfaces, may be subjected to a surface treatment by a known method such as corona discharge treatment or flame treatment for the purpose of increasing the wetting tension. It is preferable from the point of improving.

According to the present invention, an easy-to-print layer containing a binder resin is provided on at least the surface of the base film where the pressure-sensitive adhesive layer is not formed, and the surface roughness of the easy-to-print layer is Ra 0.2 to 0.2.
It needs to be 3.5 μm. Of course, an easy print layer may be provided on both sides of the base film, but in order to have high transparency, it is preferable to form the base film on only one side (the side on which the pressure-sensitive adhesive layer is not formed).

As a method of forming the easy print layer, a method of coating the base film with the treatment liquid for easy print layer, a method of forming an anchor layer on the base film and then coating the treatment liquid for the easy print layer, a uniaxial stretching After applying the treatment solution for the easy-adhesion layer to the film, further stretching it into a biaxially stretched film, directly or after providing an anchor layer,
Examples of the method include a method of coating a treatment liquid for an easily printable layer. In addition, the easy printing layer may be constituted not only by a single coat layer but also by a plurality of layers.

The binder resin used for the easy-to-print layer is not particularly limited, and the formed easy-to-print layer may have a designed surface roughness Ra of 0.2 to 3.5 μm. As the binder resin, an ester bond (—CO—O—)
It is preferred to include at least one polymer containing, such polymers are acrylic acid, methacrylic acid, one or more polymers and copolymers of acrylates and methacrylates, polyester resins, ethylene resins −
It is preferable to be selected from a vinyl acetate copolymer and a vinyl chloride-vinyl acetate copolymer.

The binder resin comprises at least one ester bond-containing polymer (a) having a glass transition temperature of -20 to 20 ° C. and at least one ester bond having a glass transition temperature of 40 to 80 ° C. Polymer (b)
Is preferably selected from a mixture with In this mixture, the mixed polymerization ratio is (b) :( a) is 3 by weight ratio.
The ratio is preferably from 0:70 to 90:10.

The acrylic resin used for the binder resin includes, for example, acrylic acid, methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, sec-butyl acrylate, tert-butyl acrylate, Pentyl acrylate, heptyl acrylate, hexyl acrylate, octyl acrylate, hexadecyl acrylate, dimethylpropyl acrylate, ethyl propyl acrylate, cyclohexyl acrylate, phenyl acrylate, benzyl acrylate, 2-tert-butyl acrylate Phenyl,
Naphthol acrylate, chlorophenyl acrylate, cyanobenzyl acrylate, cyanophenyl acrylate,
Homopolymers of thiabutyl acrylate, isobornyl acrylate, methacrylic acid, methyl methacrylate, butyl methacrylate and copolymers of two or more of these, and copolymers of one or more of these with styrene be able to.

Examples of the polyester resin used for the binder resin include, for example, polymer data handbooks, such as poly-2-hydroxyacetic acid, polyhydroxypropionic acid, polyethylene oxalate, polymethylene azelate, and polyethylene terephthalate. Edition-(editor of the Society of Polymer Science, Baifukan, published in 1986) 532
To 533 pages. Further, the above-mentioned polyester resin may be modified with hydroxyl or carboxyl. The ethylene-vinyl acetate copolymer-based resin and the vinyl chloride-vinyl acetate copolymer-based resin used for the binder resin include those obtained by modifying them with hydroxy or carboxyl.

In the easily printed layer of the pressure-sensitive adhesive sheet of the present invention,
The binder resin preferably contains an organic pigment and / or an inorganic pigment. As the organic pigment, an acrylic resin pigment, a polystyrene resin pigment, a styrene-acryl copolymer resin pigment, and the like can be exemplified. As the inorganic pigment, a silicon dioxide pigment can be exemplified as a preferable material.
The average particle size of the pigment is preferably 1 to 10 μm, more preferably 4 to 8 μm, and a true spherical particle is particularly preferable. The content of the pigment is preferably 0.1 to 2% by weight based on the total amount of the easily printable layer.
If the average particle size is less than 1 μm, blocking may occur during printing. When the average particle diameter exceeds 10 μm, the pigment is easily peeled off from the easy-to-print layer, which may cause blocking, and may further cause uneven printing in letterpress printing.

Known methods for coating these easy-to-print layers can be used, for example, a metaling bar method, a gravure roll method, an air knife method, a spray method, a reverse roll method, and the like. Preferably the thickness of the easily printed layer is 0.5 to 5 g / m ^2, printability, preferably 0.7~3g / m ² from the haze. By the way, if it is less than 0.5 g / m ² , it may be peeled off from the easy print layer and the base film or the anchor layer. Also, 5g
If it exceeds / m ² , transparency may be reduced, or drying may be insufficient in a coating step, and blocking may occur.

According to the present invention, the JIS
Arithmetic mean roughness Ra measured in B0601-1994
Needs to be 0.2 to 3.5 μm. The arithmetic average roughness Ra may be adjusted by appropriately selecting a resin, a pigment, and the like used for the easy-to-print layer, a coating method, drying conditions, and the like. Incidentally, when Ra is less than 0.2 μm, blocking tends to occur when the film is wound in a printing process or the like. If Ra exceeds 3.5 μm, the haze becomes large and becomes almost opaque.

In order to improve the adhesion between the easy print layer and the base film (for example, a polypropylene film), an anchor layer containing an adhesive resin can be provided between the easy print layer and the base film.

Examples of the adhesive resin for the anchor layer include, but are not limited to, isocyanate compounds, resins having an oxazoline group, and resins having an ethyleneimine group. The isocyanate-based compounds may be used alone or as a mixture of two or more. Further, the resin having an oxazoline group and the resin having an ethylimine group may be used alone,
A mixture of two or more of these may be used, and may be used in combination with an epoxy compound to improve water resistance.

Known methods for coating the anchor layer, for example, methods such as a metaling bar method, a gravure roll method, an air knife method, a spray method, and a reverse roll method can be used. The coating amount of the anchor layer is about 0.01 to 1 g / m ² , preferably about 0.1 g / m ² .
The range is from 03 to 0.3 g / m ² .

The uniaxially stretched film is coated with an easy-adhesion layer, and is further stretched, for example, by the following method. The polypropylene composition is melt-extruded according to a conventional method, and is first stretched in the machine direction to obtain a machine direction uniaxially stretched film. Next, after coating with an easy-to-adhesive agent, it can be obtained by sufficiently drying and stretching in the lateral direction. Examples of easy adhesives include ionomer-based polyolefin copolymers, acrylic resins, vinylidene chloride, polybutadiene, EVA, silane coupling agents, ethylene-
Ethyl acrylate-maleic anhydride copolymer and the like can be mentioned.

Known methods for coating the surface of the polypropylene film with the easy-adhesive can be used, for example, a metalling bar method, a gravure roll method, an air knife method, a spray method, a reverse roll method and the like. When an easy-adhesion layer is formed between the base film and the anchor layer or between the base film and the easy-to-print layer, the adhesion between the anchor layer and the easy-to-print layer is improved. The coating amount of the easy-adhesive layer is about 0.001 to 0.4 g / m ² , preferably in the range of 0.005 to 0.2 g / m ² .

The pressure-sensitive adhesive used in the present invention is not particularly limited as a constituent component, and may be of a solvent type, an emulsion type, a hot type or the like such as a rubber type, an acrylic type, a vinyl ether type, a urethane type or a silicone type. There is a melt type and the like. In particular, an acrylic premonomer or an acrylic resin containing an acrylic monomer as a main component is preferable from the viewpoint of transparency and weather resistance.

The acrylic resin is not particularly limited.
Vinyl monomer having an acrylic group, vinyl monomer having an epoxy group, vinyl monomer having an alkoxyl group, vinyl monomer having an ethylene oxide group,
Vinyl monomer having an amino group, vinyl monomer having an amide group, vinyl monomer having a halogen atom,
A vinyl monomer having a phosphate group, a vinyl monomer having a sulfonic acid group, a vinyl monomer having a silane group,
Examples include those containing a vinyl monomer having a phenyl group, a vinyl monomer having a benzyl group, a vinyl monomer having a tetrahydrofurfuryl group, and other copolymerizable monomers. The acrylic resin is a bulk polymerization method, a solution polymerization method, a suspension polymerization method, and an emulsion polymerization method in which a monomer insoluble or hardly soluble in water is dispersed together with an emulsifier and polymerization is performed using a water-soluble polymerization initiator. And the like. Above all, the pressure-sensitive adhesive obtained by the emulsion polymerization method is preferable because high coagulation can be obtained without using a crosslinking agent, and it is energy-saving and environmentally friendly.

In order to improve the adhesive properties of these acrylic resins, various additives such as natural resins such as rosin, modified rosin, rosin and derivatives of modified rosin, polyterpene resins, modified terpene, aliphatic hydrocarbon resins, Pentadiene resins, aromatic petroleum resins, phenolic resins, alkyl-phenol-acetylene resins, cumarone-indene resins, tackifiers including vinyl toluene-α-methylstyrene copolymers, antioxidants, Softeners such as stabilizers and oils, fillers, stabilizers and the like can be added as necessary. These may be used in combination of two or more as necessary. An organic UV absorber such as benzophenone or benzotriazole may be added to the pressure-sensitive adhesive layer in order to improve weather resistance.

In order to form the pressure-sensitive adhesive layer, the pressure-sensitive adhesive as described above is applied to a release sheet, dried if necessary to form a pressure-sensitive adhesive layer, and bonded to a surface substrate.
The pressure-sensitive adhesive sheet of the present invention is obtained. Applicators for this adhesive include reverse roll coaters, knife coaters,
A bar coater, a slot die coater, an air knife coater, a reverse gravure coater, a variogravure coater and the like are used, and the coating amount is 5 to 50 g / dry weight.
in the range of m ^2, more preferably it is adjusted from 10 to 30 g / m ^2. If the amount is less than 5 g / m ² , the adhesive strength to the adherend will be insufficient. On the other hand, if it exceeds 50 g / m ² , the adhesive may protrude or the printability may be deteriorated.

The release sheet for covering the pressure-sensitive adhesive layer is not particularly limited, and paper such as high-density base paper such as glassine paper, clay-coated paper, kraft paper or high-quality paper laminated with a film such as polyethylene, or high-quality paper A dry weight of a fluororesin or silicone resin is applied to a paper coated with polyvinyl alcohol or acrylate copolymer resin or a plastic film such as polyethylene terephthalate or polypropylene to a weight of about 0.1 to 3 g / m ^2. What has been applied and provided with a release agent layer by thermal curing, ionizing radiation curing, or the like is appropriately used.

As a coating apparatus for the release agent layer, a bar coater, an air knife coater, a direct gravure coater, an offset gravure coater, a multi-stage roll coater and the like are appropriately used. In the case where transparency is required, it is better to use a plastic film release sheet than a paper release sheet in terms of transparency and smoothness. In addition, the release sheet made of a plastic film is not affected by temperature and humidity, and is therefore less likely to curl than a paper-based release sheet.

The pressure-sensitive adhesive sheet thus obtained preferably has a haze of 1.0 to 6.0% in the constitution of the surface substrate and the pressure-sensitive adhesive layer from which the release sheet has been peeled off. Further, the release sheet of the pressure-sensitive adhesive sheet is peeled off, affixed to a transparent substrate, and ultraviolet rays (295 to 400 n
m) was irradiated with 7.2 MJ / m ² , and L ^* a ^* before and after the irradiation ^.
It is preferable that ΔE ^* determined from b ^* (CIELAB) is 1.0 or less because of excellent light resistance. In the present invention, a polypropylene film (PY-1) is used as a transparent substrate.
01, thickness 50 μm, manufactured by Oji Paper Co., Ltd.).

[0036]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should be understood that the present invention is by no means restricted thereto.

Example 1 (Production of Surface Substrate) A biaxially oriented polypropylene film (trade name "PY-101", manufactured by Oji Paper Co., Ltd.) (thickness: 50 μm) was used as a substrate film. One surface of this film is coated with a vinyl chloride-vinyl acetate copolymer resin (trade name “VROH”, manufactured by Union Carbide Co.) as an anchor layer by a gravure method so as to have a concentration of 0.2 g / m ² , Next, 2.0 g of the following coating liquid for easy printing layer was used.
/ M ² by gravure coating to form an easy-to-print layer to obtain a surface substrate. "Coating liquid for easy printing layer"-10 parts of polyester resin (trade name "Byron 555", manufactured by Toyobo Co., Ltd.)-90 parts of polyester resin (trade name "Byron 200", manufactured by Toyobo Co., Ltd.)-90 parts-Organic pigment 0.1 Part (polymethyl methacrylate, true sphere, average particle size 4-5 μm, trade name “Eposter MA1004”, manufactured by Nippon Shokubai Co., Ltd.)

(Production of pressure-sensitive adhesive coating liquid) Acrylic pressure-sensitive adhesive (trade name "OPT-1", manufactured by Seiden Chemical Co., Ltd.) 1
The metal chelate crosslinking agent (trade name “M-
2 ", manufactured by Seiden Chemical Co., Ltd.), and 2 parts by weight were added and mixed to obtain an adhesive coating liquid.

(Manufacture of pressure-sensitive adhesive sheet) A commercially available polyethylene terephthalate separator (trade name "Therapeutic BK")
# 25 "(manufactured by Toyo Metallizing Co., Ltd.) with a comma coater so as to have a dry weight of 20 g / m ² and dried at 90 ° C. for 1 minute. The adhesive-free sheet was obtained by laminating the adhesive so that the surface on which the easy print layer was not formed faced the adhesive.

Example 2 A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that the coating liquid for the easily printable layer was changed to the following coating liquid. "Coating liquid for easy printing layer"-50 parts of acrylic resin (trade name "Acridic A-157", manufactured by Dainippon Ink & Chemicals, Inc.)-50 parts of acrylic resin (trade name "Acridic A-166", -Dainippon Ink and Chemicals, Inc.-1 part of organic pigment (polymethyl methacrylate, spherical, average particle size 5 to 7 µm, trade name "Eposter MA1006", manufactured by Nippon Shokubai Co., Ltd.)

Example 3 In Example 1, the anchor layer was changed to the following coating liquid,
A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1, except that the coating amount was 0.01 g / m ² . "Coating solution for anchor layer"-75 parts of polyethyleneimine (trade name "Epomin P-1000", manufactured by Nippon Shokubai)-25 parts of epoxy compound (trade name "Dinacol EX-321", manufactured by Nagase Kasei)

Example 4 An adhesive sheet was obtained in the same manner as in Example 1 except that the base film was changed to the following film. (Production of base film) Polypropylene having an intrinsic viscosity of 2.4 and a boiling n-pentane extraction residue (i, i) of 97% as measured in tetralin at 135 ° C. having a diameter of 50 mm
It was fed to an extruder of φ, melt-extruded from a T-die at 290 ° C., and cooled to 40 ° C. to prepare an unstretched sheet. The film is stretched 5 times in the machine direction, and one surface of the machine-stretched film is subjected to a corona discharge treatment by a spark gap method. Then, a solution comprising an ionomer-based polyolefin copolymer (trade name “Chempearl S-30”) is applied to the corona discharge treated surface.
0 "(manufactured by Mitsui Chemicals, Inc.) by a gravure method and dried to form an easily adhesive layer. Then, it was stretched 8 times in the transverse direction to obtain a 50 μm thick polypropylene film, which was used as a base film. Note that the coating amount of the easy-adhesion layer of the obtained base film was 0.01 g / m ² .

Example 5 In Example 1, the release sheet was replaced with a commercially available polyethylene-laminated release paper (trade name “SEPACK OKC110NC”).
Y ", manufactured by Oji Chemical Co., Ltd.) to obtain an adhesive sheet in the same manner as in Example 1.

Example 6 A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1, except that the pressure-sensitive adhesive was an emulsion-polymerized acrylic pressure-sensitive adhesive (trade name "TS-1873", Nippon Carbide Industry). .

Comparative Example 1 In the same manner as in Example 1, except that the surface substrate was a biaxially stretched polypropylene film (trade name “PY-101”, manufactured by Oji Paper Co., Ltd.) (thickness: 50 μm). To obtain an adhesive sheet.

Comparative Example 2 An adhesive sheet was obtained in the same manner as in Example 1 except that the coating liquid for the easily printable layer was changed to the following coating liquid. "Coating liquid for easy printing layer"-100 parts of polyester resin (trade name "Byron 280", manufactured by Toyobo Co., Ltd.)-Organic pigment (trade name "Eposter MA1004", manufactured by Nippon Shokubai Co., Ltd.) 3 parts

Comparative Example 3 An adhesive sheet was obtained in the same manner as in Example 1 except that the coating liquid for the easily printable layer was changed to the following coating liquid. "Coating liquid for easy printing layer"-50 parts of acrylic resin (trade name "Acridic A-157", manufactured by Dainippon Ink & Chemicals, Inc.)-50 parts of acrylic resin (trade name "Acridic A-166",・ Dai Nippon Ink Chemical Industry Co., Ltd. ・ 5 organic pigments (trade name “Eposter MA1004”, manufactured by Nippon Shokubai)

Comparative Example 4 An adhesive sheet was obtained in the same manner as in Example 1 except that the coating liquid for the easily printable layer was changed to the following coating liquid. "Coating solution for easy printing layer"-50 parts of polyester resin (trade name "Byron 530", manufactured by Toyobo Co., Ltd.)-50 parts of polyester resin (trade name "Byron 600", manufactured by Toyobo Co., Ltd.)-Organic pigment (trade name) "Eposter S-6", manufactured by Nippon Shokubai Co., Ltd.) 1 copy

Example 7 An acrylic pressure-sensitive adhesive obtained by emulsion-polymerizing the pressure-sensitive adhesive in Example 1 (trade name “MT-TACK5470E”)
E ", Mitsui Toatsu Chemicals, Inc. to obtain a pressure-sensitive adhesive sheet in the same manner as in Example 1.

The pressure-sensitive adhesive sheets thus obtained were evaluated as follows, and the results are shown in Table 1.

<Evaluation Items> [UV Letterpress Ink Adhesion] The obtained pressure-sensitive adhesive sheet was subjected to U-printing using a seal printing machine OPM-W150-3S of Onda Seisakusho.
V printing (ink used: BESTCURE UV)
-161 Sumi, manufactured by T & A TOKA Corporation). A sample printed with a seal printing machine of Onda Seisakusho was adhered with an adhesive tape (manufactured by Oji Chemical Co., Ltd.) so as not to trap air, pressed with a finger, and then peeled off by 180 ° for evaluation. ○: Ink does not come off ×: Ink comes off

[UV Flexographic Ink Adhesion Property] The obtained pressure-sensitive adhesive sheet was subjected to K printing proofer (RK Pr).
int-Coat Instruments Ltd. UV flexographic printing was carried out using (Ink used: BESTCURE UV Flexo White FP, manufactured by T & ATOKA Co., Ltd.) Adhere the printed sample with an adhesive tape (manufactured by Oji Chemical Co., Ltd.) so as not to embrace the air, and press it with your finger and then peel it 180 ° And evaluated. ○: Ink does not come off ×: Ink comes off

[Arithmetic Average Roughness] The arithmetic average roughness of the surface of the easily printable layer of the surface substrate of the obtained pressure-sensitive adhesive sheet was determined according to JIS B0.
601-1994.

[Transparency] The haze value of the obtained pressure-sensitive adhesive sheet was measured using a color computer (manufactured by Suga Test Instruments Co., Ltd.). The smaller the value, the higher the transparency.

[Weather Resistance] The obtained pressure-sensitive adhesive sheet was used as a polypropylene film (PY-101, manufactured by Oji Paper Co., Ltd.).
(Thickness: 50 μm), and then irradiated from the surface of the adhesive for 2 hours using a UV tester (made by Iwasaki Electric Co., Ltd.)
Irradiation dose of 7.2 MJ / m ² ) and L ^* a ^* b ^* (CIELAB
Was measured with a color computer (manufactured by Suga Test Instruments Co., Ltd.), and ΔE ^* was calculated from L ^* a ^* b ^* before and after UV irradiation.

[0056]

[Table 1]

[0057]

As is evident from the results in Table 1, the present invention has excellent printability not only for letter press printing but also for UV flexographic printing by using a printable polypropylene for the surface substrate. However, it was an inexpensive and printable adhesive sheet.

 ──────────────────────────────────────────────────続 き Continuing on the front page F term (reference) 4F100 AK01A AK01C AK01D AK01E AK07 AK15D AK15J AK22D AK22J AK25B AK25D AK25H AK25J AK31E AK41 JAKBAD0101 JL14C JN02 JN30 YY00 YY00D YY00H 4J004 AA05 AA08 AA10 AA11 AA14 AB01 CA03 CA04 CA06 CC03 CD10 DA02 DA03 DA04 DB02 FA01

Claims (11)

[Claims] 1. A pressure-sensitive adhesive sheet having a surface substrate, a pressure-sensitive adhesive layer, and a release sheet laminated thereon, wherein the surface substrate is a substrate film containing a synthetic polymer, and at least a surface of the substrate film on which the pressure-sensitive adhesive layer is not formed. Is a pressure-sensitive adhesive sheet having good printability, characterized by having an easy-to-print layer containing a binder resin, and having an arithmetic surface roughness Ra of 0.2 to 3.5 μm according to JIS B0601. 2. The pressure-sensitive adhesive sheet according to claim 1, wherein the binder resin for the easily printable layer contains at least one polymer containing an ester bond (—CO—O—). 3. The method according to claim 1, wherein the ester bond-containing polymer is at least one polymer and copolymer selected from acrylic acid, methacrylic acid, acrylic acid ester and methacrylic acid ester, polyester resin, ethylene-vinyl acetate copolymer. The pressure-sensitive adhesive sheet according to claim 2, wherein the pressure-sensitive adhesive sheet is selected from a coalesced product and a vinyl chloride-vinyl acetate copolymer. 4. The binder resin according to claim 1, wherein said binder resin has a glass transition temperature of -20 to 20 ° C., and at least one ester bond-containing polymer (a) having a glass transition temperature of 40 to 80 ° C. The pressure-sensitive adhesive sheet according to claim 2, which is selected from a mixture with the ester bond-containing polymer (b). 5. The pressure-sensitive adhesive sheet according to claim 1, wherein the easily printable layer contains a pigment having an average particle diameter of 1 to 10 μm. 6. The pressure-sensitive adhesive sheet according to claim 1, wherein the surface substrate has an anchor layer containing an adhesive resin formed between the substrate film and the printable layer. 7. The pressure-sensitive adhesive sheet according to claim 6, wherein the adhesive resin for an anchor layer contains at least one selected from an isocyanate compound, a resin having an oxazoline group, and a resin having an ethylimine group. 8. The pressure-sensitive adhesive according to claim 1, wherein an easy-adhesion layer containing an easily-adhesive resin is formed between the base film and the easy print layer or between the base film and the anchor layer. Sheet. 9. The pressure-sensitive adhesive sheet according to claim 1, wherein the pressure-sensitive adhesive layer is an acrylic resin layer containing an acrylate copolymer as a main component. 10. The haze of the composition of the pressure-sensitive adhesive layer and the surface base material from which the release sheet of the pressure-sensitive adhesive sheet has been peeled off is 1.0 to 6.0%.
The pressure-sensitive adhesive sheet according to any one of claims 1 to 9, wherein 11. A release sheet of an adhesive sheet is peeled off, adhered to a transparent substrate, and irradiated with ultraviolet light (295 to 400) from the transparent substrate surface.
nm) at 7.2 MJ / m ² , and L ^* a before and after the irradiation.
The pressure-sensitive adhesive sheet according to any one of claims 1 to 10, wherein ΔE ^* obtained from ^* b ^* (CIELAB) is 1.0 or less.