JPH07331193A - Pressure-sensitive adhesive sheet - Google Patents

Abstract

PURPOSE:To provide a pressure-sensitive adhesive sheet which is used outdoor or indoor for decoration or marking, is excellent in weathering resistance and staining resistance and can resist to deterioration in these properties for a long time. CONSTITUTION:This sheet is prepared by using a plasticized flexible synthetic resin film as the support, forming a coating film of a fluororesin-based coating material containing a plasticizer of the same kind as that of the plasticizer contained in the support and further containing an additive comprising a combination of an organic ultraviolet intercepting agent with a light stabilizer or a combination of an inorganic ultraviolet intercepting agent with an antioxidant on one surface of the film and forming a pressuresensitive adhesive layer on the other surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention can be used outdoors or indoors.
The present invention relates to an adhesive sheet that is used by being attached to various objects for decoration and marking.

[0002]

2. Description of the Related Art Conventionally, pressure-sensitive adhesive sheets used for decoration and marking have required properties such as weather resistance, stain resistance, conformability to adherends, and designability such as color clarity and discrimination. The weather resistance is particularly required for the pressure-sensitive adhesive sheet that is adhered to the adherend and exposed outdoors. That is, the ultraviolet rays in the sunlight cause the synthetic resins such as polyvinyl chloride, polyvinyl acetate, and polyvinylidene chloride forming the base material to decompose and become discolored or brittle, so it is necessary to cut this ultraviolet ray as much as possible. is there.

As a measure against this ultraviolet ray cut, various ultraviolet ray absorbing agents and ultraviolet ray shielding agents are added to the substrate itself of the pressure-sensitive adhesive sheet, or a coating in which these ultraviolet ray absorbing agent and ultraviolet ray shielding agent are added to the surface of the substrate is used. A method such as coating is adopted. For example, in Japanese Patent Laid-Open No. 4-152131,
Regarding a film for house agriculture, there is disclosed a technique of imparting an ultraviolet ray cutting function by applying a coating material obtained by dispersing and mixing zinc oxide powder composed of ultrafine particles having a particle diameter of 0.1 μm or less in a binder to the film.

[0004]

However, when various ultraviolet absorbers are added to the substrate itself, if the ultraviolet absorber employed is an organic one such as benzophenone type or benzotriazole type, the Therefore, there is a problem that the ultraviolet absorber is decomposed and its function is deteriorated. In addition, although the inorganic ultraviolet shielding agent has a long-lasting shielding function, it has a problem that the substrate itself is deteriorated by the photocatalytic reaction of the ultraviolet shielding agent composed of ultrafine metal particles.

On the other hand, when a coating material containing an ultraviolet absorber or an ultraviolet shielding agent is applied, there are the following problems in addition to the problem of kneading the base material itself. That is, the base material of the adhesive sheet used for decoration and marking,
As described above, polyvinyl chloride,
Synthetic resin films with high flexibility such as polyvinyl acetate are widely used. Since these films naturally contain a large amount of plasticizer, the plasticizer easily bleeds out over time, and There is a problem that not only the surface is contaminated, but also the interfacial adhesion with the coating film or the pressure-sensitive adhesive layer of the coating material such as the ultraviolet absorber is reduced.

An object of the present invention is to solve the above-mentioned drawbacks of the prior art, to provide an excellent weather resistance and stain resistance, and the effect of which is less likely to decrease with time.

[0007]

The pressure-sensitive adhesive sheet of the present invention is one in which a coating film of a paint to which an ultraviolet absorber or an ultraviolet shielding agent is added is formed on one surface of a substrate. In addition, a plasticizer of the same type as the plasticizer contained in the base material is blended, and further, an organic ultraviolet absorber and a light stabilizer,
Alternatively, the main point is that the coating film is formed using a solvent-soluble fluororesin coating material containing an additive that is any combination of an inorganic ultraviolet shielding agent and an antioxidant.

The fluororesin, which serves as a binder for the above-mentioned paint, originally has a high molecular weight and is a crystalline polymer so that it is difficult to dissolve in an organic solvent. Therefore, the means for forming the fluororesin layer is as follows. Previously, there was no method other than using a dispersion type paint or a powder high temperature baking type paint, but since an organic solvent soluble type room temperature curable paint was recently developed, in the present invention, in particular, A solvent-soluble fluororesin is used as a binder.

In the present invention, the solvent-soluble fluororesin coating material is used to utilize the weather resistance and stain resistance of the resin. Examples of the fluororesin-based coating material include fluoroolefin-vinyl ether copolymer,
Examples thereof include those using a copolymer of vinylidene fluoride-4 fluoroethylene-6 fluoroethylene as a binder, and the latter is preferred. Also, as a binder,
In addition to using these fluororesins alone, it is also possible to use a blend resin in which an acrylic resin is mixed in an amount of 10 to 70% by weight. This blended resin is preferable because the adhesion to the base material is further improved and the followability of the coating film to the base material is also improved. The acrylic resin used at this time was 2 ethylhexyl acrylate-
Acrylic acid-vinyl acetate copolymers are preferred.

The use of a plasticizer as one of the additive components for the binder of the paint is one of the important features of the present invention. As the plasticizer, the same kind of plasticizer as that used for the base film must be used, and the desired effect cannot be obtained with other kinds of plasticizer. By using this plasticizer, migration of the plasticizer from the substrate film to the coating film, the pressure-sensitive adhesive layer, and further to the surface of the pressure-sensitive adhesive sheet can be effectively suppressed.

Other additive components to the binder of the paint include additives which are a combination of an organic UV absorber and a light stabilizer, or an inorganic UV screening agent and an antioxidant. Benzophenone-based organic ultraviolet absorbers,
Conventionally known materials such as benzotriazole can be used, but in the coating material used in the present invention, a light stabilizer is used in combination with these organic ultraviolet absorbers. Compared with the case where the conventional organic UV absorber is used alone, the combined use not only imparts the durability of the UV blocking function, but is also effective in preventing the bleed-out of the plasticizer. As the light stabilizer, a phosphate type is preferable.

Further, an inorganic UV screening agent may be used instead of the organic UV absorber. Examples of the inorganic ultraviolet shielding agent include powders of metal oxides such as titanium oxide and zinc oxide. In the coating material used in the present invention, an antioxidant is used in combination with these inorganic ultraviolet shielding agents. is there. By the combined use, the photocatalytic reaction of the metal oxide can be suppressed. As the antioxidant, a hindered amine antioxidant is suitable.

The amount of each additive compounded in the above-mentioned fluororesin coating material is 100 parts by weight of the binder resin.
Plasticizer 1 to 20 parts by weight, organic UV absorber 0.5
It is preferable that the amount is ˜6 parts by weight (or 1 to 50 parts by weight for the inorganic ultraviolet shielding agent) and 0.5 to 4 parts by weight for the light stabilizer (or 0.1 to 2 parts by weight for the antioxidant). If the compounding amount of each additive deviates from these ranges, the effect of using the additive cannot be expected.

As the base film used in the pressure-sensitive adhesive sheet of the present invention, a soft synthetic resin film containing a plasticizer is adopted. That is, polyvinyl chloride, polyvinylidene chloride,
Films of polyvinyl acetate, polyvinyl butyral, polyacrylic acid ester, etc. are used. These soft films usually contain about 30 to 60% of dioctyl phthalate, dibutyl phthalate and other plasticizers. In addition to the above, an ultraviolet absorber, a stabilizer, a coloring agent and the like are often contained.

The method for producing the pressure-sensitive adhesive sheet of the present invention includes:
On one surface of the substrate film, the above-mentioned fluororesin coating material is applied and dried to form a coating film, and on the other surface, an adhesive agent is applied to form an adhesive layer, and on the adhesive layer Further, a method of laminating a release paper, or a casting molding process paper is coated and dried to form a coating film, and a synthetic resin solution for substrate formation is applied and dried to form a substrate film. It is possible to adopt various methods such as a method of forming a two-layer film, further laminating an adhesive layer and a peeling layer on top of this, and then releasing from the process paper.

[0016]

In the pressure-sensitive adhesive sheet of the present invention, since the coating film of the solvent-soluble fluororesin paint is formed on one surface of the substrate, the weather resistance and stain resistance of this resin can be utilized.

Further, since the same kind of plasticizer as the plasticizer in the base film is added to the fluororesin coating, it is possible to more reliably prevent the bleed-out of the plasticizer in the base film. The coating film has excellent adhesion and stain resistance.

Further, since the fluororesin paint contains an additive which is any combination of an organic ultraviolet absorber and a light stabilizer, or an inorganic ultraviolet shielding agent and an antioxidant, the organic resin is used. In the case of UV absorbers, the durability of the UV blocking function of the absorber is ensured,
Even if a light stabilizer is included on the base film side, it also has the function of blocking its bleed-out. In the case of an inorganic UV shielding agent, the function of preventing the deterioration of the binder by the shielding agent. It is also equipped.

[0019]

EXAMPLES Examples of the present invention will be described in detail below.

Example 1 Preparation of Fluororesin-Based Paint Binder: Vinylidene fluoride-4 Fluoroethylene-6 Fluoroethylene Copolymer Fluororesin made of 2 ethylhexyl acrylate-acrylic acid-vinyl acetate copolymer Fluororesin paint (Floren manufactured by Japan Synthetic Rubber Co., Ltd.) mixed with 50% by weight of an acrylic resin composed of coalesce 100 parts by weight Organic UV absorber; 5 parts by weight benzophenone (MARK1413 manufactured by Asahi Denka Co., Ltd.) Plasticizer; Polyester type (Adeka Argus Co., P-300) 2 parts by weight Light stabilizer; Phosphate type (Asahi Denka Co., Ltd., ADEKA STAB 1500) 1 part by weight The above components were blended and prepared to obtain a fluororesin coating material. .

Molding of coating film Next, a solvent-soluble fluororesin-based coating material containing the above-mentioned compounding ingredients is formed on a casting molding process paper in which an alkyd resin coating layer having a thickness of 20 μm is formed on a high-quality paper having a thickness of 170 μm. Was applied to give a dry thickness of 15 μm.

Molding of base material film on coating surface Polyvinyl chloride; (Kanefuchi Chemical Co., PSH-10) 100 parts by weight Plasticizer; Polyester (Adeka Argus Co., P-300) 32 parts by weight Metal-based mixing stabilizer; (Asahi Denka Co., Ltd., AC-111) 8 parts by weight White pigment; Titanium oxide (Dainichi Seika Co., Ltd., VT-771) 35 parts by weight Solvent; (Mitsubishi Petrochemical Co., Solvesso) 60 Parts by weight Polyvinyl chloride organosol obtained by blending and preparing the above-mentioned respective components is applied on the surface of the coating film of the above-mentioned coating material to give a dry thickness of 40.
Casting curing was performed so that the thickness became μm, and the layers were laminated.

Formation of pressure-sensitive adhesive sheet An acrylic pressure-sensitive adhesive was applied onto the above-mentioned base material and dried to form a pressure-sensitive adhesive layer, and release paper was then applied onto it to obtain a pressure-sensitive adhesive sheet.

Example 2 Of the additives in Example 1,
Instead of a combination of an organic UV absorber and a light stabilizer, an inorganic UV screening agent having an average particle size of 0.
5% by weight of 04 μm ultrafine zinc oxide and 1% by weight of a hindered amine antioxidant (LA62 manufactured by Asahi Denka Co., Ltd.)
A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that an additive that was combined with was used.

[Comparative Example] An adhesive sheet was obtained in the same manner as in Example 1 except that the plasticizer and the light stabilizer were not added to the fluororesin coating material.

With respect to the pressure-sensitive adhesive sheet samples obtained in the above Examples and Comparative Examples, the evaluation items of weather resistance, stain resistance, and adhesion followability were measured or evaluated. The results are shown in Table 1.

The measuring method is as follows. Weather resistance: Super UV tester (manufactured by Dainippon Plastics Co., Ltd.) is used as a tester, 64 ° C, 64% R
H under the setting conditions of 90 mW / cm ² , 144 hr (equivalent to 3 years), 216 hr (equivalent to 5 years), 360 hr (8
The color difference and the floating or peeling of the coating film at each elapsed time of 432 hr (corresponding to 10 years) were measured or evaluated. The floating or peeling was evaluated by the following three grades. 3 = No occurrence. 2 = Occurred in part. 1 = Remarkably occurred. Contamination resistance: After 6 years of outdoor construction, the state of dirt adhesion on the coating surface was visually observed after 1 year, and the following 5 grades were evaluated (exposure point; Shioe, Amagasaki City, Hyogo Prefecture, construction angle; 45 Every time). 5 = hardly recognized 4 = Stain adhered to a very small part. 3 =
The whole surface is thin and dirty. 2 = Light dirt and dark dirt are mixed. 1 = The surface is markedly soiled. Adhesion followability: The sample is stretched by 10% and attached to an aluminum plate, and the state of floating and peeling of the edge of the coating film after one year from the second half of outdoor construction is visually observed and the following three stages Was evaluated (exposure point: Shioe, Amagasaki City, Hyogo Prefecture, construction angle: 45 degrees). 3 = Floating, no peeling is observed. 2 = Some floating is observed. 1 = Remarkable floating or peeling is recognized.

[0028]

[Table 1]

[0029]

The pressure-sensitive adhesive sheet of the present invention is one in which a coating film of a fluororesin-based paint is formed on one surface of a base material, and in this paint, the same kind of plasticizer as the plasticizer in the base material film is used. Fluororesin-based paints are originally included because the additives are blended, and further, the additives are any combination of organic UV absorbers and light stabilizers, or inorganic UV screening agents and antioxidants. In addition to the weather resistance and antifouling property, it has a reliable ability to prevent the bleed-out of the plasticizer in the base film and a durable UV blocking function.

Therefore, it is provided with durable weather resistance, stain resistance and coating adhesion, and is suitable for use as an adhesive sheet to be stuck outdoors or indoors for decoration or marking. .

Claims (1)

[Claims] 1. A plasticizer of the same kind as the plasticizer in the base material film is blended on one surface of a base material made of a soft synthetic resin film containing a plasticizer, and further, an organic ultraviolet absorber and a light stabilizer, or A coating film of a solvent-soluble fluororesin-based paint that contains an additive that is either a combination of an inorganic ultraviolet shielding agent and an antioxidant is formed, and an adhesive layer is formed on the other surface of the base material. An adhesive sheet characterized by being formed.