JP2005194311A - Pressure-sensitive adhesive sheet for covering surface, pressure-sensitive adhesive sheet for covering surface with mold release sheet and combination of application sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pressure-sensitive adhesive sheet for covering the surface having excellent light resistance, appearance and environmental safety, a pressure-sensitive adhesive sheet for covering the surface with a mold release sheet and a combination of application sheets. <P>SOLUTION: The pressure-sensitive adhesive sheet 10 for covering the surface is used by covering the surface in which a letter or a picture is recorded. The problems are solved by the pressure-sensitive adhesive sheet 10 for covering the surface having a transparent olefinic resin layer 1 having ≤600 MPa modulus of elasticity and a pressure-sensitive adhesive layer 2 formed on one surface of the olefinic resin layer 1. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a combination of a surface-coated pressure-sensitive adhesive sheet, a surface-coated pressure-sensitive adhesive sheet with a release sheet, and an adhesive sheet that is coated on a surface on which characters and pictures are recorded. The present invention relates to a surface-coated pressure-sensitive adhesive sheet excellent in environmental safety, a surface-coated pressure-sensitive adhesive sheet with a release sheet, and a bonded sheet.

  For outdoor advertisements and advertisements, a sheet on which letters and pictures are recorded and attached to a signboard or a vehicle body is used. Such sheets are used for the promotion and advertisement of many types of products and services, and are used for the promotion and advertisement of personal stores, etc. Need to be delivered at. As such a sheet, an image-receiving pressure-sensitive adhesive sheet is used in which an image-receiving layer capable of recording characters and pictures is formed on one surface of an image-receiving substrate and an adhesive layer is formed on the other surface. The image-receiving pressure-sensitive adhesive sheet has a desired character or pattern printed on the image-receiving layer, and is simply attached to an adherend such as a signboard or a vehicle body via the pressure-sensitive adhesive layer.

  However, if the image-receiving adhesive sheet on which characters and pictures are recorded is stuck on an adherend while the surface on which the characters and pictures are recorded is exposed, the characters and patterns may be damaged. It may become contaminated. Therefore, an image-receiving pressure-sensitive adhesive sheet on which characters and patterns are recorded is usually a transparent surface-coated pressure-sensitive adhesive in which an adhesive layer is formed on one side of a resin layer as a base material in order to protect the characters and patterns. A sheet is attached.

  The image-receiving pressure-sensitive adhesive sheet and the surface-covering pressure-sensitive adhesive sheet are usually distributed as a combination of a set of adhesive sheets, with a release sheet provided on each pressure-sensitive adhesive layer. In such a combination of adhesive sheets, a user who has purchased the combination of adhesive sheets prints, for example, a desired character or pattern on the image-receiving adhesive sheet by a desired printing method, After this image-receiving pressure-sensitive adhesive sheet is adhered to an adherend, the surface-coated pressure-sensitive adhesive sheet is adhered thereon. Then, after the advertisement display period and the like are finished, the combination of the pasting sheets that are no longer necessary is peeled off from the signboard, the vehicle body, or the like and disposed of.

  Usually, a combination of sticking sheets is used outdoors and exposed to sunlight for several months for short-term advertisements / advertisements and for about one year for long-term advertisements / advertisements. Therefore, the above-mentioned pressure-sensitive adhesive sheet for surface coating is required to have light resistance that does not deteriorate even when exposed to sunlight outdoors for about one year.

  In order to meet such requirements, the resin layer that is the base material of the above-mentioned pressure-sensitive adhesive sheet for surface coating has been conventionally formed of a vinyl chloride resin having high light resistance. However, the adhesive sheet for surface coating with the resin layer made of vinyl chloride resin may generate dioxin or other chlorine compound gas if incinerated after being peeled off. There was a problem of low nature.

In order to solve such a problem, Patent Document 1 describes that a resin layer is formed of an olefin resin that does not generate a chlorine compound gas even if incinerated, instead of a vinyl chloride resin. Yes.
Japanese Patent Laid-Open No. 2002-241712

  However, since the olefin resin is easily shrunk by irradiation with ultraviolet rays and infrared rays, the pressure-sensitive adhesive sheet for the surface coating in which the resin layer is formed of the olefin resin is a resin when used outdoors for a long time exposed to sunlight. The layer tries to shrink. On the other hand, since this resin layer is adhered to the image-receiving pressure-sensitive adhesive sheet (the image-receiving pressure-sensitive adhesive sheet is adhered to the adherend) by the pressure-sensitive adhesive layer, it cannot be freely contracted, and the resin layer In-plane tensile stress is generated. As a result, the surface-coated pressure-sensitive adhesive sheet in which the resin layer is formed of an olefin-based resin may be cracked (called a crack) in the resin layer before one year elapses when used outdoors. There was a problem of poor light resistance and appearance.

  The present invention has been made in order to solve the above-mentioned problems, and its purpose is to provide a surface-coated pressure-sensitive adhesive sheet excellent in light resistance, appearance and environmental safety, and a surface-coated pressure-sensitive adhesive sheet with a release sheet. And it is providing the combination body of an adhesive sheet.

  The pressure-sensitive adhesive sheet for surface coating of the present invention for solving the above-mentioned problems is a pressure-sensitive adhesive sheet for surface coating that is coated on the surface on which characters and pictures are recorded, and is a transparent olefin resin having an elastic modulus of 600 MPa or less It has the layer and the adhesive layer formed in the single side | surface of the said olefin resin layer, It is characterized by the above-mentioned.

  According to this invention, since the olefin resin layer of the pressure-sensitive adhesive sheet for surface coating has an elastic modulus of 600 MPa or less, ultraviolet rays and infrared rays contained in sunlight with the pressure-sensitive adhesive sheet for surface coating adhered to the adherend. , The olefin-based resin layer is elastically deformed against an in-plane tensile stress generated by preventing free contraction. Therefore, according to the present invention, the pressure-sensitive adhesive sheet for surface coating of the present invention is less likely to crack in the olefin-based resin layer even when exposed to sunlight for a long time outdoors in a state of being stuck to an adherend, Excellent light resistance and appearance.

  In the pressure-sensitive adhesive sheet for surface coating of the present invention, in the above-described pressure-sensitive adhesive sheet for surface coating, the olefin-based resin layer preferably has an elastic modulus of 350 MPa or less.

  According to this invention, since the olefin-based resin layer of the pressure-sensitive adhesive sheet for surface coating has an elastic modulus of 350 MPa or less, the pressure-sensitive adhesive sheet for surface coating of the present invention is further extended outdoors in a state of being stuck to an adherend. Even when exposed to sunlight for a period, the olefin-based resin layer hardly cracks, and is more excellent in light resistance and appearance.

  In the pressure-sensitive adhesive sheet for surface coating according to the present invention, in the pressure-sensitive adhesive sheet for surface coating, the olefin-based resin layer is preferably formed of an olefin-based thermoplastic elastomer.

  In the surface-coated pressure-sensitive adhesive sheet of the present invention, the surface-coated pressure-sensitive adhesive sheet is preferably provided with a protective layer on the surface of the olefin-based resin layer opposite to the pressure-sensitive adhesive layer.

  The surface-coated pressure-sensitive adhesive sheet with a release sheet of the present invention for solving the above-mentioned problems is characterized in that a release sheet is provided on the pressure-sensitive adhesive layer of the surface-coated pressure-sensitive adhesive sheet.

  The bonded sheet assembly of the present invention for solving the above problems has at least an image receiving layer in which characters and pictures are recorded or an image receiving layer in which characters and pictures are recorded, an image receiving substrate and an adhesive layer, The adhesive sheet is a combination of an adhesive sheet for image reception in which the respective layers are formed in this order and an adhesive sheet for surface coating for covering the adhesive sheet for image reception, and the adhesive sheet for surface coating is It has at least a pressure-sensitive adhesive layer formed on one surface of a transparent olefin resin layer having an elastic modulus of 600 MPa or less and the olefin resin layer.

  According to the pressure-sensitive adhesive sheet for surface coating and the pressure-sensitive adhesive sheet for surface coating with a release sheet of the present invention, since the olefinic resin layer has an elastic modulus of 600 MPa or less, the olefinic resin even when exposed to sunlight outdoors for a long time. It is possible to provide a surface-coated pressure-sensitive adhesive sheet and a surface-coated pressure-sensitive adhesive sheet with a release sheet that are free from cracks in the layer and have improved light resistance, appearance, and environmental safety. Therefore, the pressure-sensitive adhesive sheet for surface coating and the pressure-sensitive adhesive sheet for surface coating with a release sheet of the present invention are preferably used for long-term outdoor (about 1 year or more) advertisements and advertisements.

  According to the combination of the adhesive sheets of the present invention, the surface-coated pressure-sensitive adhesive sheet does not crack even when exposed to sunlight for a long time outdoors, and is excellent in light resistance, appearance and environmental safety. It is possible to provide a combination of adhesive sheets that are preferably used for advertising and advertisements.

  Hereinafter, the pressure-sensitive adhesive sheet for surface coating of the present invention, the pressure-sensitive adhesive sheet for surface coating with a release sheet of the present invention, the combination of the adhesive sheet of the present invention, and the image receiving material constituting the combination of the adhesive sheet of the present invention The pressure-sensitive adhesive sheet will be described in detail with reference to the drawings.

(1) Surface coating adhesive sheet:
FIG. 1 is a cross-sectional view showing an example of the pressure-sensitive adhesive sheet 10 for surface coating according to the present invention. As shown in FIG. 1, the surface-coated pressure-sensitive adhesive sheet 10 of the present invention has a transparent olefin resin layer 1 and a pressure-sensitive adhesive layer 2 formed on one surface of the olefin resin layer 1.

  The pressure-sensitive adhesive sheet 10 for surface coating according to the present invention covers an image-receiving pressure-sensitive adhesive sheet on which characters and pictures are recorded, thereby protecting the letters and pictures from scratches and contamination.

(Olefin resin layer)
In the surface-coated pressure-sensitive adhesive sheet 10 of the present invention, the olefin-based resin layer 1 has an elastic modulus of 600 MPa or less, and sees through characters and patterns recorded on the image-receiving pressure-sensitive adhesive sheet that is the adherend of the surface-coated pressure-sensitive adhesive sheet 10. Transparency to the extent possible.

The surface covering pressure-sensitive adhesive sheet 10 having an olefin resin layer 1 having an elastic modulus of 600 MPa or less was exposed to sunlight outdoors for about one year while being stuck to an adherend through the pressure-sensitive adhesive layer 2. In this case (as will be described later, this corresponds to a case where ultraviolet rays having a wavelength of 295 to 450 nm are irradiated at an illuminance of 60 mW / cm ² for about 100 hours under a temperature condition assuming outdoor exposure). . The reason is that the olefinic resin layer 1 is flexible even when a tensile stress in the in-plane direction is generated due to the shrinkage of the olefinic resin layer 1 by irradiation with sunlight including ultraviolet rays or infrared rays. This is because it elastically deforms and follows the tensile stress.

In particular, the pressure-sensitive adhesive sheet for surface coating 10 having an olefin resin layer 1 having an elastic modulus of 350 MPa or less is exposed to sunlight outdoors for about two years while being stuck to an adherend via the pressure-sensitive adhesive layer 2. (Corresponding to the case where ultraviolet rays in the wavelength band of 295 to 450 nm are irradiated for about 200 hours at an illuminance of 60 mW / cm ² under the temperature conditions assuming outdoor exposure, as will be described later). Cracks are unlikely to occur.

  The lower limit of the elastic modulus of the olefin-based resin layer 1 is determined in consideration of ease of handling when the olefin-based resin layer 1 is manufactured, and is usually about 300 MPa, although it depends on the composition of the olefin-based resin that is the material. That is, an olefin resin layer having an elastic modulus of less than 300 MPa may be cut or deformed when it is produced by sheeting (sheeting) using a calendar roll machine or the like.

  Here, the elastic modulus is measured by a plastic tensile test method of JIS-K7113. Specifically, the olefin resin layer 1 processed into the shape of No. 2 type test piece was subjected to a tensile test under the conditions of 25 ° C., a tensile speed of 50 mm / min, and a distance between grips of 80 mm, and measured data. It is a value calculated based on

  The transparency of the olefin-based resin layer 1 may be such that the characters and the patterns recorded on the image-receiving pressure-sensitive adhesive sheet that is the adherend of the surface-coated pressure-sensitive adhesive sheet 10 can be seen through. For example, the visible light transmittance of the olefin resin layer 1 is preferably 70% or more.

  The olefin resin layer 1 is formed of olefin resin such as polyethylene, polypropylene, polybutene, ethylene-propylene copolymer, ethylene-propylene-butene copolymer, ethylene-vinyl alcohol copolymer or olefin thermoplastic elastomer. ing. These olefin-based resins may be used alone as long as the above-described elastic modulus can be obtained, or may be mixed and used for adjusting the elastic modulus of the olefin-based resin layer 1.

  The olefin resin layer 1 is preferably formed of an olefin thermoplastic elastomer. When such an olefin resin is used, it is easy to form the olefin resin layer 1 having an elastic modulus of 600 MPa or less. As the olefin-based thermoplastic elastomer, an olefin-based thermoplastic elastomer that is a mixture of a hard segment made of a crystalline olefin resin and a soft segment made of an amorphous olefin resin can be used. For example, (A) Olefin-based thermoplastic elastomers described in JP-A-5-77371, (B) Olefin-based thermoplastic elastomers described in JP-A-7-316358, (C) JP-B-6-23278 Examples thereof include the olefinic thermoplastic elastomers described. As the olefinic thermoplastic elastomer, (D) an olefinic thermoplastic elastomer which is a mixture of a hard segment made of a crystalline olefinic resin and a soft segment made of a partially crosslinked olefinic elastomer (rubber). For example, (D-1) an olefinic thermoplastic elastomer described in JP-B-53-21021 and (D-2) olefin-based thermoplastic described in JP-B-53-34210. Examples thereof include elastomers and (D-3) olefinic thermoplastic elastomers described in JP-B-56-15741.

  The olefinic thermoplastic elastomer (A) is a resin in which crystalline polypropylene as a hard segment is mixed with amorphous polyolefin as a soft segment in which the weight ratio of the propylene component is 50% by weight or more. Preferred examples of the crystalline polypropylene include a propylene-ethylene random copolymer and a propylene-1 butene random copolymer. Preferable examples of the amorphous polyolefin include propylene-1 butene-ethylene terpolymer. When this olefinic thermoplastic elastomer is used, the olefinic resin layer 1 which is rich in flexibility and excellent in transparency and mechanical strength can be formed.

  The olefinic thermoplastic elastomer (B) is a composition in which a crystalline polyolefin as a hard segment is mixed with a low crystalline polyolefin as a soft segment in which the content of propylene and / or 1-butene is 50% by weight or more. It is a resin in which 0.5 parts by weight or more of an oil gelling agent such as an N acylamino acid amine salt or an N acylamino acid ester is added to 100 parts by weight. When this olefinic thermoplastic elastomer is used, it is possible to form the olefinic resin layer 1 which is rich in flexibility and whose surface tackiness is suppressed.

  The olefinic thermoplastic elastomer (C) has a melt index of 0.1 to 4 g / 10 min, isotactic polypropylene as a hard segment insoluble in boiling heptane, a number average molecular weight Mn of 25,000 or more, and a weight average A soft polypropylene composed of atactic polypropylene as a soft segment soluble in boiling heptane in which the ratio of the molecular weight Mw to the number average molecular weight Mn is Mw / Mn ≦ 7. When this olefinic thermoplastic elastomer is used, the olefinic resin layer 1 which is rich in flexibility and excellent in mechanical properties can be formed.

  The olefinic thermoplastic elastomer (D-1) is produced by uniformly blending and mixing a crystalline olefin polymer as a hard segment and a partially cross-linked monoolefin copolymer rubber as a soft segment. Resin. Examples of the crystalline olefin polymer that is a hard segment include polyethylene, polypropylene, and polymethylpentene. Examples of the monoolefin copolymer rubber that is a soft segment include ethylene-propylene copolymer rubber, ethylene-propylene-non-polymer. Examples thereof include conjugated terpolymer diene rubber.

  The olefinic thermoplastic elastomer (D-2) is prepared by mixing an olefinic polymer as a hard segment and an uncrosslinked monoolefin copolymer rubber as a soft segment with the addition of a crosslinking agent, and melt kneading. This is a resin produced by partially crosslinking the soft segment.

  The olefinic thermoplastic elastomer (D-3) comprises a peroxide-decomposable olefinic polymer as a hard segment, a peroxide-crosslinked olefinic copolymer rubber and a peroxide non-crosslinked hydrocarbon rubber as a soft segment, It is a resin produced by adding a mineral oil softener such as a paraffinic or naphthenic softener and mixing them, and then melt-kneading them in the presence of an organic peroxide to partially crosslink soft segments. The peroxide-decomposable olefin polymer as a hard segment has the property that the molecular weight decreases and the fluidity increases when mixed and heated with a peroxide. As such a polymer, for example, isotactic polypropylene is used. , Propylene-ethylene copolymer, propylene-butene-1 copolymer and the like. Peroxide-crosslinked olefin copolymer rubber as a soft segment has the property of cross-linking and reducing fluidity when mixed with peroxide and heated, and examples of such copolymer rubber include ethylene- Examples include propylene copolymer rubber and ethylene-propylene-nonconjugated terpolymer diene rubber. Peroxide non-crosslinked hydrocarbon rubber as a soft segment has the property that it does not crosslink even when heated with peroxide and does not change in fluidity. Examples of such hydrocarbon rubber include polyisobutylene and butyl rubber. Is mentioned.

  The weight ratio of the hard segment to the soft segment (hard segment: soft segment) in the olefinic thermoplastic elastomer is usually 10:90 to 90:10, and the elastic modulus of the olefinic resin layer 1 is within this range. Is adjusted to 600 MPa or less. For example, when the blending ratio of the soft segment is increased within this range, the elastic modulus of the olefin resin layer 1 can be decreased.

  The olefin resin layer 1 may contain an inorganic filler or the like as necessary. As the inorganic filler, powder having an average particle size of about 0.1 to 10 μm, such as calcium carbonate, barium sulfate, clay, and talc, is used. From the viewpoint of securing the elastic modulus of the olefin resin layer 1, the amount of the inorganic filler added is preferably about 0 to 20% by weight. Moreover, a heat stabilizer, a flame retardant, a ultraviolet absorber, a radical scavenger, etc. may be added to the olefin resin layer 1 as long as the olefin resin layer 1 can have the above elastic modulus.

  For the olefin-based resin layer 1, a material obtained by melt-kneading the above-described forming material and molding it into a sheet or film by a calendar method or the like is used. An axially stretched one is used. The thickness of the olefin resin layer 1 is preferably 40 to 100 μm. If the thickness of the olefin-based resin layer 1 is larger than 100 μm, the surface-coated pressure-sensitive adhesive sheet 10 becomes too thick and it becomes difficult to attach the surface-coated pressure-sensitive adhesive sheet 10. On the other hand, if the thickness of the olefin resin layer 1 is less than 40 μm, the surface covering pressure-sensitive adhesive sheet 10 may become too thin to sufficiently protect characters and patterns recorded on the image-receiving pressure-sensitive adhesive sheet.

  One or both surfaces of the olefin-based resin layer 1 are preferably subjected to easy adhesion treatment such as application of an easy adhesion primer layer, corona discharge treatment, plasma treatment, and ozone treatment. When easy adhesion treatment is performed on the surface of the olefin-based resin layer 1, the adhesiveness with the pressure-sensitive adhesive layer 2 and a protective layer 3 described later is improved. As the easy adhesion primer layer (also referred to as anchor coat), polyester resin, urethane resin, chlorinated polypropylene, or the like can be used.

  Since such olefin-based resin layer 1 is not incinerated when chlorine compound-based gas such as dioxin is generated, the environmental safety of the pressure-sensitive adhesive sheet 10 for surface coating is improved.

(Adhesive layer)
The pressure-sensitive adhesive layer 2 is formed on one surface of the olefin-based resin layer 1 for the purpose of bonding the olefin-based resin layer 1 to an image-receiving pressure-sensitive adhesive sheet on which characters and patterns are recorded. The pressure-sensitive adhesive layer 2 is usually a solid surface layer that is uniformly formed.

  It is preferable that the pressure-sensitive adhesive layer 2 has transparency enough to allow the characters and patterns recorded on the image-receiving pressure-sensitive adhesive sheet to be the adherend of the surface-coated pressure-sensitive adhesive sheet 10 to be seen through. Specifically, the visible light transmittance of the pressure-sensitive adhesive layer 2 is preferably about 60% or more.

  Examples of the pressure-sensitive adhesive used for forming the pressure-sensitive adhesive layer 2 include acrylic pressure-sensitive adhesives such as homopolymers of (meth) acrylic acid esters or copolymers of (meth) acrylic acid esters and other monomers, Synthetic rubber adhesives such as isoprene rubber, polybutadiene rubber or styrene-butadiene rubber, or natural rubber adhesives may be mentioned. “(Meth) acrylic acid” means acrylic acid or methacrylic acid. If necessary, a tackifier, a crosslinking agent, an antioxidant, an ultraviolet absorber and the like may be added to the adhesive.

  The pressure-sensitive adhesive layer 2 is formed by applying a coating agent in which the above-described pressure-sensitive adhesive is dissolved / dispersed in a solvent to a release sheet, with the coated surface of the release sheet opposed to one side of the olefin resin layer 1 It is formed by a transfer method in which the pressure-sensitive adhesive layer 2 is laminated on the olefin resin layer 1. As a method of applying the coating agent to the release sheet, a comma coating method, a roll coating method, or the like can be used, and the thickness of the pressure-sensitive adhesive layer 2 is preferably 5 to 30 μm. The release sheet used here is provided on the pressure-sensitive adhesive layer 2 as it is, and becomes a release sheet 4 described later.

(Protective layer)
As shown in FIG. 1B, the surface covering pressure-sensitive adhesive sheet 10 may be provided with a protective layer 3 on the surface opposite to the pressure-sensitive adhesive layer 2 side of the olefin-based resin layer 1. The protective layer 3 is provided on the olefin resin layer 1 and has a role of protecting the olefin resin layer 1 from scratches.

  It is preferable that the protective layer 3 has transparency enough to allow the characters and patterns recorded on the image-receiving pressure-sensitive adhesive sheet to be the adherend of the surface-coated pressure-sensitive adhesive sheet 10 to be seen through. Specifically, the visible light transmittance of the protective layer 3 is preferably 70% or more.

  Examples of the material of the protective layer 3 include a thermosetting resin and an ionizing radiation curable resin. Here, ionizing radiation means electromagnetic waves or charged particles having energy capable of polymerizing or crosslinking molecules, and usually electron beams (EB) or ultraviolet rays (UV). In the resin forming the protective layer 3, a crosslinking agent, a heat stabilizer, a flame retardant, an ultraviolet absorber, a radical scavenger and the like may be added.

  The protective layer 3 is formed by applying and curing a coating agent in which the above materials are dissolved and dispersed in a solvent as necessary on the olefin resin layer 1. The thickness of the protective layer 3 is preferably 1 to 10 μm.

(Surface coating adhesive sheet)
Since the elastic modulus of the olefin-based resin layer 1 is 600 MPa or less, the surface covering pressure-sensitive adhesive sheet 10 of the present invention is attached to an adherend through the pressure-sensitive adhesive layer 2 under temperature conditions assuming outdoor exposure. Thus, in the light resistance test in which ultraviolet rays in the wavelength band of 295 to 450 nm are irradiated at an illuminance of 60 mW / cm ² , the olefin resin layer 1 is hardly cracked even after 100 hours. Moreover, the pressure-sensitive adhesive sheet for surface coating having an elastic modulus of the olefin resin layer larger than 600 MPa may cause yellowing of the pressure-sensitive adhesive layer 2 before 100 hours have passed in this light resistance test, but the olefin resin layer 1 In the pressure-sensitive adhesive sheet 10 for surface coating having an elastic modulus of 600 MPa or less, such yellowing is unlikely to occur in the pressure-sensitive adhesive layer 2.

  Furthermore, when the elastic modulus of the olefin resin layer 1 is 350 MPa or less, the surface covering pressure-sensitive adhesive sheet 10 is unlikely to crack in the olefin resin layer 1 even after 200 hours in the above light resistance test. Moreover, the pressure-sensitive adhesive sheet for surface coating having an elastic modulus of the olefin resin layer 1 larger than 350 MPa is cracked in the olefin resin layer 1 before 200 hours have passed in this light resistance test, and further the pressure-sensitive adhesive layer. 2 may be yellowed or the adhesive strength of the pressure-sensitive adhesive layer 2 may be reduced, but the surface-coated pressure-sensitive adhesive sheet 10 having an elastic modulus of the olefin-based resin layer 1 of 350 MPa or less is applied to the olefin-based resin layer 1. Cracks are unlikely to occur, and yellowing or a decrease in adhesive strength is unlikely to occur in the adhesive layer 2. Such a decrease in the adhesive strength of the pressure-sensitive adhesive layer is caused by contraction stress in the in-plane direction acting on the adjacent pressure-sensitive adhesive layer 2 as the olefin resin layer irradiated with ultraviolet rays tends to contract. On the other hand, in the pressure-sensitive adhesive sheet 10 for surface coating according to the present invention, the olefin-based resin layer 1 is flexible, and shrinkage stress in the in-plane direction is unlikely to occur in the pressure-sensitive adhesive layer 2, so that the pressure-sensitive adhesive force of the pressure-sensitive adhesive layer 2 is unlikely to decrease. .

For the light resistance test, an eye super UV tester (Iwasaki Electric Co., Ltd.) is used as a light resistance tester. This light resistance tester removes the influence of extra wavelengths by removing ultraviolet rays with a wavelength of 295 nm or less and visible light with a wavelength of 450 nm or more that are not included in the sunlight reaching the ground surface, and is close to outdoor exposure. It is a light resistance tester that enables realistic acceleration of deterioration. The irradiation conditions of ultraviolet rays in the light resistance test are as follows: the illuminance is 60 mW / cm ² , the distance from the light source is 240 mm, the black panel temperature is 46 ° C., and a stainless steel plate is used as the adherend of the surface coating pressure-sensitive adhesive sheet 10. To do. The “black panel temperature” is a temperature for controlling the temperature in the light resistance tester assuming the temperature of the sheet surface when infrared rays contained in sunlight are irradiated.

  100 hours of UV irradiation in this light resistance test corresponds to exposure to sunlight for one year outdoors, and 200 hours of UV irradiation corresponds to exposure to sunlight for two years outdoors. That is, the surface covering pressure-sensitive adhesive sheet 10 of the present invention having an elastic modulus of the olefin resin layer 1 of 600 MPa or less hardly cracks in the olefin resin layer 1 even when exposed outdoors for one year. Since the appearance of characters and patterns recorded on the image-receiving pressure-sensitive adhesive sheet is not impaired, it is preferably used for advertisements and advertisements exposed for a long time outdoors. In addition, the pressure-sensitive adhesive sheet for surface coating 10 having an elastic modulus of the olefin-based resin layer 1 of 350 MPa or less is not likely to crack in the olefin-based resin layer 1 even if it is exposed outdoors for two years, and therefore is exposed to the outdoors for a longer period of time. It is preferably used for advertising and advertising.

  Moreover, since this surface-coated pressure-sensitive adhesive sheet 10 has the olefin-based resin layer 1 that does not generate a chlorine-based gas even when incinerated as described above, it is excellent in environmental safety.

(2) Adhesive sheet for surface coating with release sheet:
FIG. 2 is a cross-sectional view showing an example of the pressure-sensitive adhesive sheet with a release sheet of the present invention. As shown in FIG. 2, the surface-coated pressure-sensitive adhesive sheet 100 with a release sheet of the present invention is provided with a release sheet 4 on the pressure-sensitive adhesive layer 2 of the surface-coated pressure-sensitive adhesive sheet 10 of the present invention. .

  The release sheet 4 is a surface-coated pressure-sensitive adhesive sheet for the purpose of preventing the pressure-sensitive adhesive layer 2 from inadvertently adhering to other objects or blocking when the surface-coated pressure-sensitive adhesive sheet 10 is wound up. 10 is provided on the pressure-sensitive adhesive layer 2 and is temporarily bonded to the pressure-sensitive adhesive layer 2 until the surface-coated pressure-sensitive adhesive sheet 10 is used.

  As the release sheet 4, a release agent such as silicon resin is applied to the surface of paper such as high-quality paper, linter paper, sulfuric acid paper, glassine paper, kraft paper, or a resin sheet such as polyester resin or olefin resin. The machined one is used. The thickness of the release sheet 4 is usually 25 to 75 μm.

(3) Image-receiving adhesive sheet:
The image-receiving pressure-sensitive adhesive sheet constitutes a combination of the adhesive sheet of the present invention together with the above-mentioned surface-coated pressure-sensitive adhesive sheet, and is used as a recording medium on which characters and designs for advertisements and advertisements are recorded by printing or the like .

  FIG. 3A is a cross-sectional view illustrating an example of the image receiving pressure-sensitive adhesive sheet. As shown in FIG. 3A, the image-receiving pressure-sensitive adhesive sheet 20 is provided with an image-receiving layer 22 on which one surface of the image-receiving substrate 21 is recorded with characters and patterns, and the other surface of the image-receiving substrate 21 is adhesive. An agent layer 23 is provided. FIG. 3B is a cross-sectional view illustrating an example of the image-receiving pressure-sensitive adhesive sheet 200 with a release sheet. In the image-receiving pressure-sensitive adhesive sheet 200 with a release sheet, a release sheet 24 is provided on the pressure-sensitive adhesive layer 23 of the image-receiving pressure-sensitive adhesive sheet 20.

  The image receiving substrate 21 is preferably formed of the same olefin resin as the olefin resin layer 1 described above from the viewpoint of environmental safety. The image receiving substrate 21 formed of an olefin resin preferably has an elastic modulus larger than that of the olefin resin layer 1 of the surface covering pressure-sensitive adhesive sheet 10. When the elastic modulus of the image receiving substrate 21 is larger than the elastic modulus of the olefin resin layer 1, the image receiving adhesive sheet 20 and the surface covering adhesive sheet 10 having such an image receiving substrate 21 and the olefin resin layer 1 are combined. Then, when it is stuck and exposed outdoors for a long time, the olefin-based resin layer 1 of the pressure-sensitive adhesive sheet 10 for surface coating is more unlikely to crack.

  The image receiving base material 21 preferably contains a colorant and has a concealing property so that the color and pattern of the adherend are not seen through. The color of the image receiving substrate 21 is preferably white that can record a desired character or pattern for general use, and may be black or chromatic depending on the application. Colorants include titanium white, antimony white, lead white, carbon black (black), yellow lead, titanium yellow, vermilion, cadmium red, ultramarine, cobalt blue and other inorganic pigments, isoindolinone yellow, quinacridone red, phthalocyanine blue Organic pigments and dyes such as metal pigments made of foil powder such as aluminum or brass, or pearlescent pigments made of foil powder such as titanium dioxide-coated mica or basic zinc carbonate are used. In addition, the thickness of the image receiving base material 21 is 20-100 micrometers normally.

  The image receiving layer 22 has a property of recording characters and pictures. That is, since characters and pictures are usually recorded with ink, the surface of the image receiving layer 22 on which characters and pictures are recorded has a property of repelling ink and closely contacting with ink (hereinafter referred to as ink acceptability).

  The image receiving layer 22 is formed of a resin having ink receptivity to ink used for recording characters and pictures. As such a resin, for example, urethane resin, polyester resin, acrylic resin, cellulose resin, vinyl chloride-vinyl acetate copolymer, etc. can be used alone, or two or more of these resins can be mixed. Can be used. In addition, the thickness of the image receiving layer 22 is 1-10 micrometers normally.

  An extender is preferably added to the image receiving layer 22. When the extender pigment is added, the surface of the image receiving layer 22 is roughened or made porous, and the ink receiving property of the image receiving layer 22 is improved. As extender pigments, calcium carbonate, silica, barium sulfate, porous ceramics, kaolinite, zeolite, white clay, diatomaceous earth, and the like can be used. Further, in order to improve the ink receiving property of the image receiving layer 22, the surface of the image receiving layer 22 may be subjected to corona discharge treatment, ozone treatment or the like.

  The pressure-sensitive adhesive layer 23 is provided on the surface of the image receiving substrate 21 opposite to the image receiving layer 22 for the purpose of bonding the image receiving substrate 21 and an adherend (signboard, vehicle body, etc.).

  As the pressure-sensitive adhesive used for forming the pressure-sensitive adhesive layer 23, the same pressure-sensitive adhesive as that of the pressure-sensitive adhesive layer 2 provided on the surface-coated pressure-sensitive adhesive sheet 10 can be used. A colorant may be added to the pressure-sensitive adhesive to supplement the concealability of the image receiving substrate 21. As the colorant, the same colorant as that of the image receiving substrate 21 can be used.

  The pressure-sensitive adhesive layer 23 is formed by a transfer method using a release sheet, similarly to the formation of the pressure-sensitive adhesive layer 2 of the surface-coated pressure-sensitive adhesive sheet 10. As the release sheet, the same one as the release sheet 4 provided on the surface-coated pressure-sensitive adhesive sheet 100 with a release sheet can be used, as in the case of the surface-coated pressure-sensitive adhesive sheet 100 with a release sheet, The release sheet 24 of the image-receiving adhesive sheet 200 with the release sheet is provided on the adhesive layer 23 as it is. In addition, it is preferable that the thickness of the adhesive layer 23 is 5-30 micrometers.

(4) Bonded sheet combination:
In the combination of the adhesive sheets of the present invention, the image receiving layer 22 on which characters and pictures are recorded or the image receiving layer 22 on which characters and pictures are recorded, the image receiving substrate 21 and the adhesive layer 23 are formed in this order. The image-receiving pressure-sensitive adhesive sheet 20 and the surface-coated pressure-sensitive adhesive sheet 10 of the present invention for covering the image-receiving pressure-sensitive adhesive sheet 20 are combined.

  In FIG. 4, an example of the combination body of the sticking sheet of this invention is shown. As shown in FIG. 4, the surface covering pressure-sensitive adhesive sheet 10 and the image receiving pressure-sensitive adhesive sheet 20 are usually provided with a release sheet 4 or a release sheet 24 on the pressure-sensitive adhesive layer of each sheet, and a surface coating with a release sheet. It is stored and distributed as the pressure-sensitive adhesive sheet 100 and the image-receiving pressure-sensitive adhesive sheet 200 with a release sheet. The form of these sheets may be a form of a take-up roll obtained by winding a long sheet, or may be a form of a single sheet obtained by processing the sheet into a desired shape such as a rectangle.

  The usage method of the combination body of the sticking sheet of this invention is demonstrated based on FIGS. First, an adhesive sheet combination in which a release sheet is provided on the pressure-sensitive adhesive layer of each sheet is prepared, and desired characters and designs are placed on the image-receiving layer 22 of the image-receiving pressure-sensitive adhesive sheet 200 with a release sheet. Recording is performed by a desired printing method or the like (FIG. 5). Here, the code | symbol 25 shows the ink which records a character and a picture. Examples of the printing method include silk screen printing, ink jet printing, sublimation transfer printing, electrophotographic printing, and heat-sensitive color printing.

  Next, the release sheet 24 of the image-receiving adhesive sheet 200 with the release sheet on which characters and pictures are recorded is peeled off, and the image-receiving adhesive sheet 20 is attached to a signboard, a vehicle body or the like through the exposed adhesive layer 23. It sticks to the body 26 (FIG. 6). FIG. 7 shows a state where the image receiving pressure-sensitive adhesive sheet 20 is adhered to the adherend 26.

  Thereafter, the release sheet 4 of the surface-coated adhesive sheet 100 with a release sheet is peeled off, and the surface-coated adhesive sheet 10 is adhered to the adherend 26 through the exposed adhesive layer 2. It sticks on the sheet | seat 20 (FIG. 8). FIG. 9 shows a state where the surface covering pressure-sensitive adhesive sheet 10 and the image receiving pressure-sensitive adhesive sheet 20 are combined and adhered to the adherend 26. After the advertisement display period and the like are finished, the surface covering pressure-sensitive adhesive sheet 10 and the image receiving pressure-sensitive adhesive sheet 20 are peeled off from the adherend 26.

  Such an adhesive sheet combination of the present invention is free from cracks even when the surface covering pressure-sensitive adhesive sheet 10 is exposed to sunlight for a long time outdoors, and is excellent in light resistance, appearance and environmental safety. It is preferably used for advertisements and advertisements. Specific examples of the adherend sheet assembly include a building window, a door, an outer wall, a floor, a car body such as a bus or a train, and an outer surface of a vending machine.

  Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples. Hereinafter, “part” means “part by weight”.

Example 1
As the olefin resin layer, a polypropylene olefin thermoplastic elastomer sheet (thickness: 80 μm) prepared by mixing a hard segment made of crystalline polypropylene and a soft segment made of olefin elastomer to have an elastic modulus of 600 MPa. ) Was used. First, a corona discharge treatment is applied to both surfaces of the olefin resin layer, and a protective layer coating agent A having the following composition is applied to one surface of the olefin resin layer by a gravure roll coating method. Under curing for 3 days, a protective layer having a thickness of 3 μm made of acrylic urethane resin was formed. The elastic modulus of the olefin resin layer was measured by the plastic tensile test method of JIS-K7113 as described above in the description of the olefin resin layer.

Coating agent A for protective layer;
-100 parts of acrylic polyol-10 parts of hexamethylene diisocyanate-Mixed solvent of toluene and methyl ethyl ketone (weight ratio 1: 1)

  Next, a 25 μm thick polyethylene terephthalate film having a release agent layer made of silicon resin on one side was used as a release sheet, and a pressure-sensitive adhesive layer coating agent B having the following composition was commad on the release agent layer. It was applied by a coating method and dried to form an adhesive layer having a thickness of 25 μm.

Coating agent B for adhesive layer;
・ Acrylic resin 100 parts ・ Hexamethylene diisocyanate 0.5 part ・ Mixed solvent of toluene and methyl ethyl ketone (weight ratio 1: 1)

  Thereafter, the pressure-sensitive adhesive coated surface of the release sheet and the surface opposite to the protective layer side of the olefin resin layer are pressed and laminated, and then cured for 3 days under a temperature condition of 40 ° C. The adhesive sheet for surface coating with a release sheet of Example 1 was obtained.

(Example 2)
In the production of the surface-coated pressure-sensitive adhesive sheet with a release sheet of Example 1, a polypropylene-based olefin-based thermoplastic elastomer sheet (thickness: 80 μm) adjusted to have an elastic modulus of 500 MPa was used as the olefin-based resin layer. A surface-coated pressure-sensitive adhesive sheet with a release sheet of Example 2 was obtained in the same manner as Example 1 except for the above.

(Example 3)
In the production of the pressure-sensitive adhesive sheet with a release sheet of Example 1, a polypropylene-based olefin-based thermoplastic elastomer sheet (thickness: 80 μm) adjusted to have an elastic modulus of 400 MPa was used as the olefin-based resin layer. A surface-coated pressure-sensitive adhesive sheet with a release sheet of Example 3 was obtained in the same manner as Example 1 except for the above.

(Example 4)
In the production of the surface-coated pressure-sensitive adhesive sheet with a release sheet of Example 1, a polypropylene-based olefin-based thermoplastic elastomer sheet (thickness 80 μm) adjusted to have an elastic modulus of 350 MPa was used as the olefin-based resin layer. A surface-coated pressure-sensitive adhesive sheet with a release sheet of Example 4 was obtained in the same manner as Example 1 except for the above.

(Example 5)
In the production of the pressure-sensitive adhesive sheet with a release sheet of Example 1, a polypropylene-based olefin-based thermoplastic elastomer sheet (thickness: 80 μm) adjusted to have an elastic modulus of 300 MPa was used as the olefin-based resin layer. A surface-coated pressure-sensitive adhesive sheet with a release sheet of Example 5 was obtained in the same manner as Example 1 except for the above.

(Example 6)
Next, an image-receiving adhesive sheet with a release sheet was prepared.

  First, a 25 μm-thick polyethylene terephthalate film having a release agent layer made of silicon resin formed on one side as a release sheet was used, and a pressure-sensitive adhesive layer coating agent C having the following composition was comma-coated on the release agent layer. It was coated by the method and dried to form an adhesive layer having a thickness of 25 μm.

Coating agent C for adhesive layer;
・ Acrylic resin 100 parts ・ Hexamethylene diisocyanate 0.5 part ・ Mixed solvent of toluene and methyl ethyl ketone (weight ratio 1: 1)

  Thereafter, a polypropylene-based olefin-based thermoplastic elastomer sheet (thickness: 80 μm) adjusted to have an elastic modulus of 800 MPa is used as an image receiving substrate, and corona discharge treatment is performed on both sides, and urethane resin-based on one side. An image receiving layer was formed. Laminate the surface of the image receiving substrate opposite to the image receiving layer side and the surface of the release sheet on the pressure-sensitive adhesive layer side, and then cure for 3 days under a temperature condition of 40 ° C. with a release sheet. An image-receiving adhesive sheet was obtained.

(Comparative Example 1)
In the production of the surface-coated pressure-sensitive adhesive sheet with a release sheet of Example 1, a polypropylene-based olefin-based thermoplastic elastomer sheet (thickness 80 μm) adjusted to have an elastic modulus of 1000 MPa was used as the olefin-based resin layer. A surface-coated pressure-sensitive adhesive sheet with a release sheet of Comparative Example 1 was obtained in the same manner as Example 1 except for the above.

(Comparative Example 2)
In the production of the surface-coated pressure-sensitive adhesive sheet with a release sheet of Example 1, a polypropylene-based olefin-based thermoplastic elastomer sheet (thickness: 80 μm) adjusted to have an elastic modulus of 800 MPa was used as the olefin-based resin layer. A surface-coated pressure-sensitive adhesive sheet with a release sheet of Comparative Example 2 was obtained in the same manner as Example 1 except for the above.

(Light resistance test)
About the obtained adhesive sheet for surface coating with a release sheet, light resistance was evaluated as follows.

The release sheet of the adhesive sheet for surface coating that was processed into a strip shape having a width of 15 mm and a length of 25 mm was peeled off, and the adhesive sheet for surface coating with the adhesive layer exposed was pressed onto a stainless steel plate having a thickness of 2 mm. Next, this stainless steel plate is placed in a light resistance tester (trade name: iSuper UV Tester, manufactured by Iwasaki Electric Co., Ltd.), the illuminance is 60 mW / cm ² , the distance from the light source is 240 mm, and the black panel temperature is 46 ° C. Under the conditions, ultraviolet rays in a wavelength band of 295 to 450 nm were irradiated.

  The irradiation time of ultraviolet rays was set to 50 to 200 hours, and the presence or absence of cracks, the presence or absence of yellowing, and the presence or absence of natural peeling due to a decrease in adhesive strength were observed visually every 25 hours. The results are shown in Table 1. When the surface coating pressure-sensitive adhesive sheet was not cracked, ○, when it was cracked x, when the surface coating pressure-sensitive adhesive sheet was not yellowed, when yellowing was observed X, and the case where natural peeling of the pressure-sensitive adhesive sheet for surface coating was not recognized was evaluated as ◯, and the case where natural peeling was observed was evaluated as x. In the table,-(hyphen) indicates that evaluation was not performed.

  The surface-coated pressure-sensitive adhesive sheets of Examples 1 to 5 did not cause cracks in the olefin-based resin layer and did not cause yellowing of the pressure-sensitive adhesive layer even when irradiated with ultraviolet rays for 100 hours. On the other hand, the surface-coated pressure-sensitive adhesive sheets of Comparative Examples 1 to 3 were cracked in the olefin-based resin layer and yellowed in the pressure-sensitive adhesive layer before the ultraviolet irradiation time passed 100 hours. The surface-coated pressure-sensitive adhesive sheet of Example 5 was not cracked in the olefin-based resin layer and yellowed in the pressure-sensitive adhesive layer even when irradiated with ultraviolet rays for up to 200 hours.

1A is a cross-sectional view showing an example of the pressure-sensitive adhesive sheet for surface coating of the present invention, and FIG. 1B is a cross-sectional view showing another example of the pressure-sensitive adhesive sheet for surface coating of the present invention. It is sectional drawing which shows an example of the adhesive sheet for surface coating | cover with a release sheet of this invention. FIG. 3A is a cross-sectional view showing an example of the image-receiving pressure-sensitive adhesive sheet, and FIG. 3B is a cross-sectional view showing an example of the image-receiving pressure-sensitive adhesive sheet with a release sheet. It is sectional drawing which shows an example of the combination body of the sticking sheet of this invention. It is sectional drawing for demonstrating the usage method of the combination body of the sticking sheet of this invention. It is sectional drawing for demonstrating the usage method of the combination body of the sticking sheet of this invention. It is sectional drawing for demonstrating the usage method of the combination body of the sticking sheet of this invention. It is sectional drawing for demonstrating the usage method of the combination body of the sticking sheet of this invention. It is sectional drawing for demonstrating the usage method of the combination body of the sticking sheet of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Olefin-type resin layer 2 Adhesive layer 3 Protective layer 4 Release sheet 10 Surface coating adhesive sheet 20 Image receiving adhesive sheet 21 Image receiving substrate 22 Image receiving layer 23 Adhesive layer 24 Release sheet 100 For surface coating with release sheet Adhesive sheet 200 Adhesive sheet for receiving images with release sheet

Claims (6)

It is a pressure-sensitive adhesive sheet for covering a surface on which a character or a pattern is recorded,
A pressure-sensitive adhesive sheet for surface coating, comprising a transparent olefin resin layer having an elastic modulus of 600 MPa or less and a pressure-sensitive adhesive layer formed on one side of the olefin resin layer.   The pressure-sensitive adhesive sheet for surface coating according to claim 1, wherein the olefin-based resin layer has an elastic modulus of 350 MPa or less.   The pressure-sensitive adhesive sheet for surface coating according to claim 1 or 2, wherein the olefin-based resin layer is formed of an olefin-based thermoplastic elastomer.   The pressure-sensitive adhesive sheet for surface coating according to any one of claims 1 to 3, wherein a protective layer is provided on the surface of the olefin resin layer opposite to the pressure-sensitive adhesive layer side.   A release sheet with a release sheet is provided on the pressure-sensitive adhesive layer of the adhesive sheet for surface coating according to any one of claims 1 to 4. An image receiving layer on which characters and pictures are recorded or an image receiving layer on which characters and pictures are recorded, an image receiving substrate and an adhesive layer, and an image receiving adhesive sheet in which each layer is formed in this order, and the image receiving adhesive It is a combination of an adhesive sheet and a pressure-sensitive adhesive sheet for surface coating for covering the sheet,
The adhesive sheet for surface coating has at least a transparent olefin resin layer having an elastic modulus of 600 MPa or less, and an adhesive layer formed on one side of the olefin resin layer. Combination body.

Images