JP2697930B2 - Thermosetting coating sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention relates to a sheet for covering which is used by protecting the surface of articles such as furniture and steel plate, decorating, displaying, etc., by sticking to the surface of those articles and heat curing. It is about.

(Prior Art) When decorating or displaying on the surface of furniture, steel plate or the like, paint is generally used. However, when a solvent-based paint is used, the working environment is deteriorated because the organic solvent is volatilized during the work, which is a problem in environmental hygiene. The use of a water-based paint does not impair the working environment, but has the problem that the drying time of the paint is prolonged or that a large amount of energy is required for drying the paint.

Therefore, recently, a sheet-like adhesive material mainly composed of polyvinyl chloride has been proposed. This paste material
Furniture, to be attached to the surface of articles such as steel plates, when using this adhesive material, there is no adverse effect on the work environment,
And there is no need for drying. However, this sheet-like bonding material is mainly formed of soft polyvinyl chloride, and has a drawback that it is inferior in hardness and scratch resistance.

As a method of improving this, a technique has been proposed in which a sheet having a high surface hardness can be obtained by curing a sheet material after application. For example, Japanese Patent Publication No. 57-13425 discloses that a porous sheet-like substrate is impregnated with a radical reaction initiator, and a layer containing a polymer and a radical-reactive monomer is laminated on one or both surfaces thereof. Thermoset composite sheets have been proposed. Further, JP-A-58-57472
In Japanese Patent Application Laid-Open Publication No. H11-264, there is proposed a sheet-like paint comprising a surface layer portion rich in semi-curable resin content and a back layer portion rich in hot melt resin content.

(Problems to be Solved by the Invention) However, the composite sheet disclosed in Japanese Patent Publication No. 57-13425 has a structure in which a layer having a radically reactive unsaturated compound and a layer having a radical reaction initiator are laminated. Therefore, in order to perform a uniform curing reaction during heating and pressing, it is necessary to bring both layers into uniform contact, and it is difficult to control heating and pressing. Further, since a sheet-like substrate impregnated with a radical reaction initiator is made of paper, woven fabric, non-woven fabric, or the like, when the composite sheet is coated on the surface of an article having unevenness or a curved surface, the composite sheet is stretched. There is a drawback that it is difficult to cause "wrinkles" and it is difficult to form a good coating on the surface of the article. Furthermore, since the composite sheet has no adhesiveness to the article before heating, when the composite sheet is attached to the surface of the article, it is necessary to temporarily fix the composite sheet to the article mechanically. There is a drawback that the property is bad.

Further, in the sheet-shaped paint disclosed in Japanese Patent Application Laid-Open No. 58-57472, the back surface has no tackiness at room temperature,
The workability at the time of sticking to the surface of the article is poor, and when the article to which the sheet-like paint is stuck has a high temperature, the back surface is softened and the tackiness is reduced. In addition, since the back surface is formed of a hot melt layer, there is a disadvantage that the hardness is insufficient at normal temperature or high temperature.

The present invention is intended to solve the above-mentioned drawbacks, and its object is to provide good spreadability and flexibility before curing, and to well coat the surface of an article having unevenness or a curved surface. It is another object of the present invention to provide a thermosetting coating sheet which can form a coating film which is easy to perform coating operation, is uniform after curing, has excellent impact resistance and adhesion, and has high hardness.

(Means for Solving the Problems) The thermosetting coating sheet of the first invention has a weight average molecular weight.
On one surface of the coating layer containing 100,000 to 1,000,000 solid reactive acrylic resin and blocked isocyanate, a pressure-sensitive adhesive layer containing a saturated polyester resin having a hydroxyl group or a carboxyl group and a blocked isocyanate is laminated, Thereby, the above object is achieved.

The thermosetting coating sheet of the second invention has a weight average molecular weight
100,000-1,000,000 solid reactive acrylic resin, blocked isocyanate and weight average molecular weight 1,000-10,000
On one surface of a coating layer containing at least one of a reactive acrylic oligomer and a solid thermoplastic resin, a pressure-sensitive adhesive layer containing a saturated polyester resin having a hydroxyl group or a carboxyl group and a blocked isocyanate is laminated, Thereby, the above object is achieved.

 Hereinafter, the present invention will be described in detail.

The sheet for thermosetting coating of the first invention is formed by laminating an adhesive layer on one side of a coating layer. The coating layer contains a solid reactive acrylic resin having a weight average molecular weight of 100,000 to 1,000,000 and a blocked isocyanate, and the pressure-sensitive adhesive layer contains a saturated copolymerized polyester resin having a hydroxyl group and a blocked isocyanate.

The reactive acrylic resin contained in the coating layer is an acrylic polymer having a plurality of hydroxyl groups, amino groups and / or carboxyl groups, and is a solid polymer at normal temperature (25 ° C.). Such a reactive acrylic resin includes, for example, a (meth) acrylate monomer, a styrene derivative monomer, a (meth) acrylate monomer having a hydroxyl group such as 2-hydroxyethyl (meth) acrylate, and 2-amino. It is obtained by copolymerizing a monomer having an amino group such as ethyl (meth) acrylate and / or a monomer having a carboxyl group such as (meth) acrylic acid. The weight average molecular weight of the reactive acrylic resin can be changed depending on the conditions when a polymerization reaction is performed using an initiator, and the reactive acrylic resin used in the first invention has a weight average molecular weight of 100,000 to A range of 1,000,000 is selected. When the weight average molecular weight is less than 100,000, it is difficult for the obtained thermosetting coating sheet to maintain the sheet shape. Therefore, for example, sufficient elongation with respect to the stretching during the sticking operation cannot be obtained, and in some cases, cracks and cracks occur. Conversely, if the weight average molecular weight is 1,
If it exceeds 000, 000, the composition with the blocked isocyanate is inferior in moldability, and it becomes difficult to prepare a thermosetting coating sheet.

The blocked isocyanate contained in the coating layer,
It is used as a heat-reactive curing agent for curing the reactive acrylic resin during heating. Here, the blocked isocyanate means a compound obtained by blocking an isocyanate group of an isocyanate compound having two or more isocyanate groups in a molecule with a blocking agent such as phenol, oxime, ε-caprolactam, and malonic ester. Examples of the isocyanate compound include monomers such as tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate, or adducts thereof, modified isocyanurates, modified carbodiimides, and the like. In the blocked isocyanate, the above-mentioned blocking agent is eliminated by heating, and the generated isocyanate group is converted into a functional group (a sum of a hydroxyl group, an amino group and a carboxyl group. The functional group value is a hydroxyl value, an amino group value and an acid value. The amino value is a value obtained by calculating the amount of amino groups added during polymerization in the same manner as the hydroxyl value or by quantifying the amount of amino groups by reacting the amino groups with nitrous acid to convert them to hydroxyl groups. The amount of carboxyl group to be calculated is calculated in the same manner as the amount of hydroxyl group or the value of carboxyl group determined by KOH group). The content of the blocked isocyanate is preferably adjusted so that the ratio of the functional group contained in the reactive acrylic resin and the isocyanate group contained in the blocked isocyanate is in the range of 0.5 to 1.5, and more preferably. Is 0.8
It is in the range of ~ 1.2.

A coating layer is formed from the composition of the solid reactive acrylic resin and the blocked isocyanate. This coating layer is formed by heating at a predetermined temperature or higher to form a hard coating.

In addition, the coating layer may contain a filler, an antioxidant, a coloring agent, and the like, if necessary. As a coloring agent,
Pigments, dyes, and the like used in ordinary painting can be used. For example, pigments include titanium oxide, iron oxide, carbon black, cyanine pigments, quinacridone pigments, and dyes include azo dyes, anthraquinone dyes, indigoid dyes, and stilbene dyes, and aluminum flakes and nickel powder. Metal powder such as gold powder and silver powder may be added. When using a colorant having a high hiding property, the amount of the total colorant is 2-1 to 100 parts by weight of the solid content of the resin.
A range of 00 parts by weight is preferred.

As the saturated polyester resin having a hydroxyl group or a carboxyl group contained in the pressure-sensitive adhesive layer,
Those having a molecular weight of 5,000 to 25,000, an OH value or an acid value of 2 to 20 are preferably used. Since this resin has a hydroxyl group or a carboxyl group at a molecular terminal, the hardness can be increased by curing with a urethane resin, a melamine resin, an epoxy resin, or the like.

The blocked isocyanate contained in the pressure-sensitive adhesive layer is used for curing the saturated polyester resin contained in the pressure-sensitive adhesive layer. This blocked isocyanate can be the same as that used for the coating layer, and its content is included in the blocked isocyanate and the reactive group obtained by combining the hydroxyl group and the carboxyl group contained in the saturated polyester resin. It is preferably adjusted so that the ratio with the isocyanate group is in the range of 0.5 to 1.5, and more preferably in the range of 0.8 to 1.2.

A pressure-sensitive adhesive layer is formed from a composition containing the above-mentioned saturated polyester resin having a hydroxyl group and a blocked isocyanate. Further, the pressure-sensitive adhesive layer may contain a filler, an antioxidant, a coloring agent, a rust inhibitor and the like used in the coating film layer, if necessary. The pressure-sensitive adhesive layer thus obtained has tackiness in a state before curing, adheres well to the above-mentioned coating layer, and adheres well to the article surface. When the pressure-sensitive adhesive layer is heated at a predetermined temperature or higher, the copolymerized polyester resin reacts with the blocked isocyanate to form a hard film.

The thermosetting coating sheet of the second invention is formed by laminating a pressure-sensitive adhesive layer on one side of a coating layer as in the first invention. The coating layer contains at least one of a reactive acrylic oligomer having a weight average molecular weight of 1,000 to 10,000 and a solid thermoplastic resin in addition to a solid reactive acrylic resin having a weight average molecular weight of 100,000 to 1,000,000 and a blocked isocyanate.

The reactive acrylic oligomer is used for obtaining flexibility and elongation of the coating layer. The reactive acrylic oligomer is an oligomer mainly composed of acrylate repeating units and having a hydroxyl amino group or / and a carboxyl group in its molecular chain, and having a weight average molecular weight of 1,
Those having a size of 0000 to 10,000 are used. When the weight average molecular weight of the reactive acrylic oligomer is less than 1,000, the flexibility of the obtained thermosetting coating sheet decreases, and cracks and cracks are apt to occur during the attaching operation. Conversely, if the weight average molecular weight is 1
If it exceeds 0,000, the plasticizing effect is lost. The reactive acrylic oligomer has a solid content of 100 of the reactive acrylic resin.
It is preferably added in an amount of 1 to 100 parts by weight, more preferably 1 to 50 parts by weight, based on parts by weight. When the addition amount of the oligomer is small, the flexibility of the thermosetting coating sheet becomes poor. Conversely, when the amount increases, the viscosity decreases and the fluidity increases, so that it becomes difficult to maintain the sheet shape.

The thermoplastic resin is solid at room temperature (25 ° C.), improves the flexibility of the thermosetting coating sheet, reduces the occurrence of cracks and the like when handling the sheet, and improves the handleability. For example, an acrylic resin, a polyester resin, a polyvinylidene fluoride resin, a styrene resin, or a polyvinyl chloride resin having good compatibility with the reactive acrylic resin is preferably used.

The thermoplastic resin has a solid content of 10 of the reactive acrylic resin.
It is preferably added in an amount of 1 to 30 parts by weight, more preferably 5 to 20 parts by weight, based on 0 parts by weight. If the amount of the thermoplastic resin is less than 1 part by weight, the flexibility of the sheet cannot be improved much, and if the amount is more than 30 parts by weight, the extensibility and hardness of the sheet will be inferior.

The reactive acrylic oligomer and the thermoplastic resin may be used alone or in combination.

In order to cure the reactive acrylic resin and the reactive acrylic oligomer, a blocked isocyanate is used as a heat-reactive curing agent. The content of the blocked isocyanate is determined by the functional groups (the sum of the hydroxyl group, the amino group, and the carboxyl group) contained in the reactive acrylic resin and the reactive acrylic oligomer. The functional group value is the total of the hydroxyl value, the amino group value, and the acid value. The amino value is a value obtained by calculating the amount of amino group added at the time of polymerization in the same manner as the hydroxyl value, or quantifying the amino group by reacting the amino group with nitrous acid to convert it to a hydroxyl group. The amount is calculated in the same manner as the amount of the hydroxyl group or the value obtained by quantifying the carboxyl group with KOH or the like) and the ratio of the isocyanate group contained in the blocked isocyanate is preferably adjusted to be in the range of 0.5 to 1.5, more preferably. Preferably it is in the range of 0.8 to 1.2.

The sheet for thermosetting coating constituted in this way may be manufactured by an arbitrary method. For example, the above-mentioned components of the coating layer are uniformly mixed, and this mixture is coated on a film that has been release-treated with a silicone release agent, and dried to form a coating layer. Next, a pressure-sensitive adhesive layer composition in which the above-mentioned pressure-sensitive adhesive layer components are uniformly mixed is applied to the surface of the coating film layer, and can be obtained by drying. The temperature of each of the above drying steps is
It is carried out at a temperature lower than the decomposition temperature of the blocked isocyanate. The thickness of the obtained thermosetting coating sheet can be adjusted according to the purpose.

(Examples) Hereinafter, the present invention will be described in detail based on examples.

Examples 1-4 Acrylic polyol (Arotan 20 manufactured by Nippon Shokubai Co., Ltd.)
40-145; glass transition temperature 40 ° C, weight average molecular weight 339,00
0, OH value 80) 100 parts by weight of solid content (hereinafter simply referred to as "part"), blocked isocyanate (Takeda Pharmaceutical Co., Ltd.)
Takenate B815N, NCO% 7.3; oxime block of hydrogenated diphenylmethane diisocyanate) 49 parts of solids were mixed with stirring. This mixture is dried on a release surface of a silicone release treated polyethylene terephthalate film (manufactured by Souken Kako Co., Ltd., film thickness: 40 μm).
Coating was performed so as to have a thickness of 100 μm, and drying was performed at 70 ° C. for 1 hour to obtain a coating layer.

On the other hand, the saturated polyester resin shown in Table 1 was dissolved in ethyl acetate so as to be 30% by weight, and the above blocked isocyanate was added in an amount having 1.0 equivalent of isocyanate group to the hydroxyl group of the saturated copolymerized polyester resin.
Mix with stirring. This is coated on the above-mentioned coating layer so that the film thickness after drying becomes 30 μm, dried at 70 ° C. for 1 hour to form an adhesive layer, and a thermosetting coating sheet with a film is formed. Obtained.

The sheet was pressure-pressed and heat-fixed to the coated steel sheet so that the pressure-sensitive adhesive layer of the sheet was adhered to the coated steel sheet, the polyethylene terephthalate film was peeled off, and then heat-cured at 160 ° C. for 30 minutes. After curing, the coating was subjected to a pencil hardness test at 25 ° C. and 80 ° C., respectively, and the adhesion of the coating was measured. The pencil hardness test is based on JIS K540
It was measured according to 0. The adhesion test was performed by cutting 100 mm gaps at 1 mm intervals on the surface of the cured thermosetting coating sheet.
A commercial adhesive tape was stuck to this, the tape was peeled off, and the result was indicated by the residual percentage of the grid. The results are shown in Table 1.

As shown in Table 1, the thermosetting coating sheets obtained in Examples 1 to 4 were good in both hardness and adhesion.

Examples 5 to 8 Acrylic polyol (Arotan 20 manufactured by Nippon Shokubai Co., Ltd.)
40-145) at a solid content of 100 parts, acrylic polyol oligomer (Nippon Carbide Co., Ltd., Nicalite H870) at a solid content of 30 parts and block isocyanate (Takeda Pharmaceutical Co., Ltd., Takenate B-815N) solid content And 86 parts were mixed with stirring.

This mixture was subjected to a silicone release-treated polyethylene terephthalate film (manufactured by Souken Kako Co., Ltd.,
m) The thermosetting coating was applied in the same manner as in Example 1 except that the release surface was coated so that the film thickness after drying was 100 μm, and dried at 70 ° C. for 1 hour to obtain a coating layer. Sheet was obtained.

The obtained thermosetting coating sheet was cured in the same manner as in Example 1, and the pencil hardness and adhesion of the coating were measured.
The results are shown in Table 2.

As shown in Table 2, the thermosetting coating sheets obtained in Examples 5 to 8 had good pencil hardness and good adhesion.

Examples 9 to 12 Acrylic polyol (Arotan 20 manufactured by Nippon Shokubai Co., Ltd.)
40-145) at a solid content of 100 parts, blocked isocyanate (Takeda Pharmaceutical Co., Ltd., Takenate B-815N) at a solid content of 49 parts, acrylic resin (Kyowa Gas Chemical Industry Co., Ltd., parapet beads GIP8 or parapet) Bead EH-1000P)
And 10 parts of ethyl acetate were added and mixed with stirring.

This mixture was subjected to a silicone release-treated polyethylene terephthalate film (manufactured by Souken Kako Co., Ltd.,
m) The thermosetting coating was applied in the same manner as in Example 1 except that the release surface was coated so that the film thickness after drying was 100 μm, and dried at 70 ° C. for 1 hour to obtain a coating layer. Sheet was obtained.

The obtained thermosetting coating sheet was cured in the same manner as in Example 1, and the pencil hardness and adhesion of the coating were measured.
Table 3 shows the results.

As shown in Table 3, the thermosetting coating sheets obtained in Examples 9 to 12 were good in both pencil hardness and adhesion.

Examples 13 to 16 Acrylic polyol (Arotan 20 manufactured by Nippon Shokubai Co., Ltd.)
40-145) as solids, 100 parts of acrylic polyol oligomer (Nippon Carbide Co., Ltd., Nicalite H870) as solids, and 30 parts of blocked isocyanate (Takeda Pharmaceutical Co., Ltd., Takenate B-815N) as solids. Then, 86 parts, 10 parts of an acrylic resin (parapet bead GIP8 or parapet beads EH-1000P, manufactured by Kyowa Gas Chemical Industry Co., Ltd.) and 100 parts of ethyl acetate were added and mixed with stirring.

This mixture was subjected to a silicone release-treated polyethylene terephthalate film (manufactured by Souken Kako Co., Ltd.,
m) The thermosetting coating was applied in the same manner as in Example 1 except that the release surface was coated so that the film thickness after drying was 100 μm, and dried at 70 ° C. for 1 hour to obtain a coating layer. Sheet was obtained.

The obtained thermosetting coating sheet was cured in the same manner as in Example 1, and the pencil hardness and adhesion of the coating were measured.
Table 4 shows the results.

As shown in Table 4, the thermosetting coating sheets obtained in Examples 13 to 16 were good in both pencil hardness and adhesion.

Comparative Examples 1 to 4 An acrylic pressure-sensitive adhesive (based on 100 parts of solid content of P44 manufactured by Soken Chemical Co., Ltd.) was applied to the same coating layer as in Examples 1, 5, 9, and 13.
Table 5 shows the results of pencil hardness and adhesion of the thermosetting coating sheet obtained in the same manner as in Example 1 except for laminating only 1.7 parts of Coronate L45 manufactured by Nippon Polyurethane Industry Co., Ltd.). Indicated.

From the results in Table 5, it can be seen that the thermosetting coating sheets obtained in Comparative Examples 1 to 4 had the same adhesiveness as the sheets of the above Examples, but exhibited considerably low hardness.

Comparative Example 5 Arotan 2040-134 having a small weight average molecular weight (manufactured by Nippon Shokubai Co., Ltd., having an average molecular weight of 9.3
A mixture was obtained in the same manner as in Example 1 except that (OH value, 120) was used, and the same test as in Example 1 was performed, but it was difficult to maintain the sheet shape.

Comparative Example 6 Except for using Arotan 2040-144 having a large molecular weight (manufactured by Nippon Shokubai Co., Ltd., weight average molecular weight 103,900) as an acrylic polyol oligomer used for the coating layer,
A thermosetting coating sheet was obtained in the same manner as in Example 1, and the same test as in Example 1 was performed. The obtained thermosetting coating sheet did not have 100% elongation.

Examples 17 to 20 In 300 parts by weight of ethyl acetate, a reactive acrylic resin (copolymer of methyl methacrylate, methacrylic acid and 2-aminoethyl acrylate, Mw = 492,000, Tg 35 ° C., COOH value 4
0 and NH ₂ valent 40) 100 parts by weight of solid content, blocked isocyanate (Takenate B-870N, oxime block of isophorone diisocyanate NCO = 12.6%, manufactured by Takeda Pharmaceutical) 3
4 parts by weight (the crosslinking agent has 0.9 equivalent of isocyanate group based on the functional group of the reactive acrylic resin) was added and mixed with stirring. This mixture was applied to the release surface of a polyethylene terephthalate (PET) film subjected to a silicone release treatment with an applicator, and dried at 80 ° C. for 5 minutes to prepare a thermosetting sheet. Sheet thickness is 80μ
m.

On the other hand, the saturated polyester resin shown in Table 6 was dissolved in ethyl acetate so as to be 30% by weight, and the above blocked isocyanate was added in an amount having 1.0 equivalent of isocyanate group to the hydroxyl group of the saturated copolymerized polyester resin.
Mix with stirring. This is coated on the above-mentioned coating layer so that the film thickness after drying becomes 30 μm, dried at 70 ° C. for 1 hour to form an adhesive layer, and a thermosetting coating sheet with a film is formed. Obtained.

The sheet was pressure-pressed and heat-pressed against the coated steel sheet such that the pressure-sensitive adhesive layer of the sheet was adhered to the coated steel sheet, the polyethylene terephthalate film was peeled off, and then heat-cured at 160 ° C for 30 minutes. After curing, the coating was subjected to a pencil hardness test at 25 ° C. and 80 ° C., respectively, and the adhesion of the coating was measured. The pencil hardness test is JIS K54
It was measured according to 00. The adhesion test was performed by cutting 100 mm gaps at 1 mm intervals on the surface of the cured thermosetting coating sheet.
A commercial adhesive tape was stuck to this, the tape was peeled off, and the result was indicated by the residual percentage of the grid. Table 6 shows the results.

As shown in Table 6, the thermosetting coating sheets obtained in Examples 17 to 20 were good in both hardness and adhesion.

Examples 21 to 24 In 300 parts by weight of ethyl acetate, a reactive acrylic resin (copolymer of methyl methacrylate, methacrylic acid and 2-aminoethyl acrylate, Mw = 565,000, Tg 35 ° C., COOH number 4
0 and NH ₂ valence 40) to a solid content of 100 parts by weight, a reactive acrylic oligomer (methyl acrylate, 2-hydroxyethyl methacrylate, butyl acrylate, copolymer of methacrylic acid, Mw = 4,000, Tg− 10 ° C, OH number 100, COOH value 40) 30 parts by weight of solid content, 75 parts by weight of blocked isocyanate (Takenate B-815N, ketoxime block of hydrogenated diphenylmethane diisocyanate NCO 7.3% NCO 7.3%) The agent had 1.0 equivalent of an isocyanate group based on the functional groups of the reactive acrylic resin and the reactive acrylic oligomer), and was mixed with good stirring. This mixture was applied to the release surface of a polyethylene terephthalate (PET) film subjected to a silicone release treatment with an applicator, and dried at 80 ° C. for 5 minutes to prepare a thermosetting sheet. The thickness of the sheet was 80 μm.

The obtained thermosetting coating sheet was cured in the same manner as in Example 1, and the pencil hardness and adhesion of the coating were measured.
Table 7 shows the results.

As shown in Table 7, the thermosetting coating sheets obtained in Examples 5 to 8 had good pencil hardness and good adhesion.

(Effects of the Invention) The configuration of the thermosetting coating sheet of the present invention is as described above. Under the curing temperature or lower, the sheet has excellent spreadability and flexibility, and is not only flat but also slightly uneven or curved. Can be satisfactorily coated on an article surface having no wrinkles. Moreover, since the pressure-sensitive adhesive layer can be adhered to the surface of the article, the coating operation is easy. In addition, the thermosetting coating sheet can form a strong and uniform coating excellent in hardness and abrasion resistance because the coating layer and the pressure-sensitive adhesive layer are both cured by heating.

Claims (2)

(57) [Claims] An adhesive containing a saturated polyester resin having a hydroxyl group or a carboxyl group and a block isocyanate on one surface of a coating layer containing a solid reactive acrylic resin having a weight average molecular weight of 100,000 to 1,000,000 and a block isocyanate. A thermosetting coating sheet on which an agent layer is laminated. 2. One surface of a coating layer containing at least one of a solid reactive acrylic resin having a weight average molecular weight of 100,000 to 1,000,000, a block isocyanate, a reactive acrylic oligomer having a weight average molecular weight of 1,000 to 10,000 and a solid thermoplastic resin. A thermosetting coating sheet, on which a pressure-sensitive adhesive layer containing a saturated polyester resin having a hydroxyl group or a carboxyl group and a block isocyanate is laminated.