JPH0848954A - Protective self-adhesive film - Google Patents

Abstract

PURPOSE:To prevent the migration of an ultraviolet absorber contained in the substrate film of and the degradation with time in self-adhesiveness of a protective self-adhesive film which comprises the substrate film and a self-adhesive layer formed thereon and is used for protecting a signboard, etc. using a photographic film, a photographic paper, a poster, etc., from the discoloration by sunlight etc. CONSTITUTION:This protective self-adhesive film is obtd. by forming a self-adhesive layer on one side of a substrate film which is obtd. by molding a compsn. comprising 100 pts.wt. synthetic resin capable of forming a clear film and 5-50 pts.wt. copolymer of 5-50wt.% 2-(2'-hydroxy-5'--methacryloxyethylphenyl)-2 Hbenzotriazole and 95-50wt.% styrene or (meth)acrylic ester.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a protective pressure-sensitive adhesive film, and more particularly to a protective pressure-sensitive adhesive film for outdoor signs and the like.

[0002]

2. Description of the Related Art When characters or pictures made of photographic film or photographic paper are used as signboards, they are made of silver salt emulsion. It is easy to get discolored by receiving it. Further, when a printed matter such as a poster is used as a signboard, since it uses printing ink, it does not easily discolor, but it also discolors after a long period of time. Further, outdoors, signs such as photographic film, photographic paper, posters, etc. are damaged by rainwater, dust, etc., or by intentional destruction activities. In addition, when used indoors, it is not as affected as outdoors, but it may discolor as well and be damaged.

In order to protect the signboard from these discoloration and damage, a protective pressure-sensitive adhesive film in which a pressure-sensitive adhesive layer is laminated on a base film has been devised. In particular, in order to prevent discoloration due to sunlight or ultraviolet rays, ultraviolet rays are used. A protective adhesive film using a base film containing an absorbent has been devised and used.

[0004]

Conventionally commercially available protective pressure-sensitive adhesive films include those manufactured by Ademco Ltd. of the United Kingdom, or the product name "Overlay CT- # 10" manufactured by Sekisui Chemical Co., Ltd. However, in all cases, there is a problem that the adhesive physical properties of the pressure-sensitive adhesive deteriorate with time due to the migration of the low-molecular-weight ultraviolet absorber contained in the base film. The present invention is to solve this problem, the object is a protective pressure-sensitive adhesive film formed by laminating a pressure-sensitive adhesive layer on the base film, without migration of the ultraviolet absorber contained in the base film. Another object of the present invention is to provide a protective pressure-sensitive adhesive film that suppresses deterioration of the adhesive physical properties over time.

[0005]

The protective pressure-sensitive adhesive film of the present invention comprises 2- (2'-hydroxy-5'-methacryloxyethylphenyl) based on 100 parts by weight of a synthetic resin capable of forming a transparent film. -2H-benzotriazole 5 to 50% by weight and styrene or (meth) acrylic acid ester 95 to 50% by weight A base material obtained by molding a composition formed by adding 5 to 50 parts by weight The film is characterized in that an adhesive layer is laminated on one surface of the film.

The synthetic resin capable of forming a transparent film used in the present invention is not particularly limited as long as it can form a transparent film. For example, polyester resin such as polyethylene terephthalate, polyethylene or stretched polypropylene ( Examples thereof include polyolefin resins such as OPP), vinyl chloride resins such as soft polyvinyl chloride, and polycarbonate resins, and the thickness is preferably 10 to 100 μm.

2- (2'-hydroxy-5'-methacryloxyethylphenyl) -2H- used in the present invention
The copolymer of 5 to 50% by weight of benzotriazole and 95 to 50% by weight of styrene or (meth) acrylic acid ester is 2- (2'-hydroxy-5'-methacryloxyethylphenyl) -2H-benzotriazole 5 ~ 50% by weight and styrene or (meth) acrylic acid ester 95 ~
It is obtained by subjecting a mixture of 50% by weight to ordinary solution radical polymerization and has a weight average molecular weight of 30.
It is preferably from 00 to 500,000. In addition, the above 2
-(2'-hydroxy-5'-methacryloxyethylphenyl) -2H-benzotriazole is a compound represented by the following chemical formula.

[0008]

Embedded image

Further, as the (meth) acrylic acid ester used for producing the copolymer used in the present invention,
Examples thereof include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, and 2-hydroxyethyl methacrylate, and preferably the carbon number of the ester group. Is 1
~ 4. These (meth) acrylic acid esters may be used alone or in combination of two or more, if necessary.

The substrate film used in the present invention is 2- (2'-hydroxy-5'-methacryloxyethylphenyl) -2H based on 100 parts by weight of the synthetic resin capable of forming the transparent film. -Benzotriazole 5-5
0% by weight and styrene or (meth) acrylic acid ester 9
The composition is obtained by molding a composition containing 5 to 50 parts by weight of a copolymer with 5 to 50% by weight. When the proportion of the copolymer is reduced, the ultraviolet absorption effect is reduced. As the amount increases, the base film becomes easy to be colored.

Examples of the pressure-sensitive adhesive used in the present invention include rubber-based, urethane-based, silicone-based and acrylic-based pressure-sensitive adhesives, but those based on acrylic resin are preferred from the viewpoint of adhesive strength, durability and the like. preferable. The thickness of this pressure-sensitive adhesive layer is 10 to 10 in terms of adhesive strength to an adherend and ease of use.
50 μm is preferable.

The method for laminating the pressure-sensitive adhesive layer on the substrate film is to dissolve and disperse the compounding composition material of the pressure-sensitive adhesive in a general-purpose or industrially used organic solvent such as toluene, xylene, or ethyl acetate. To make an adhesive solution,
The pressure-sensitive adhesive layer is formed by applying the pressure-sensitive adhesive solution onto the surface of the base film and drying. The coating machine that can be used to form the pressure-sensitive adhesive layer is not particularly limited as long as it is used for ordinary pressure-sensitive adhesive solution coating, but preferably, the thickness can be accurately adjusted, Moreover, a knife coater, a comma coater, and a roll coater that can be applied with high productivity can be mentioned.

As a coating method, a pressure-sensitive adhesive solution is directly applied to the surface of the base film and dried, or a pressure-sensitive adhesive solution is once applied to release paper and dried to form a pressure-sensitive adhesive layer, and then the base film is formed. A transfer method by bonding the surface and the like can be appropriately selected.

The protective pressure-sensitive adhesive film of the present invention thus produced is usually stored as a laminate in which a release paper is attached to the pressure-sensitive adhesive layer surface, and the release paper is peeled off from the pressure-sensitive adhesive layer surface before use. use.

[0015]

The UV absorber used for the base film of the conventional protective pressure-sensitive adhesive film is a low molecular weight benzotriazole type compound having a molecular weight of 200 to 500. The film has 2- (2 '
-Hydroxy-5'-methacryloxyethylphenyl)
A copolymer of 5 to 50% by weight of -2H-benzotriazole and 95 to 50% by weight of styrene or a (meth) acrylic acid ester is used as an ultraviolet absorber. Since these ultraviolet absorbers have a high molecular weight, migration from the base film is suppressed, and therefore they do not adversely affect the adhesive physical properties of the adhesive layer.

[0016]

Embodiments of the present invention will be described below. (Example 1) Synthesis of copolymer of 2- (2'-hydroxy-5'-methacryloxyethylphenyl) -2H-benzotriazole and styrene 2- (2'-hydroxy-5'-methacryloxyethylphenyl) ) -2H-benzotriazole (manufactured by Otsuka Chemical Co., Ltd.) 30 parts by weight, styrene 70 parts by weight, and toluene 200.
And 2 parts by weight of azobisisobutyronitrile dissolved in 50 parts by weight of toluene are added dropwise over 1 hour while maintaining the temperature at 100 ° C. Then, polymerization was carried out at 110 ° C. for 3 hours. To the resulting polymer solution was added 10 times the amount of methanol to precipitate the polymer, which was filtered with a filter,
A copolymer was obtained by drying in a vacuum oven at 50 ° C. for 5 hours. When the molecular weight was measured by the GPC method, the weight average molecular weight was 10,000 in terms of polystyrene.

Molding of base film 100 parts by weight of vinyl chloride resin (average degree of polymerization 1300),
To 100 parts by weight of a soft vinyl chloride resin composition consisting of 50 parts by weight of a plasticizer and 2 parts by weight of a metal-based stabilizer, 10 parts by weight of the above-obtained copolymer was added, kneaded, and calendered. To a 60 μm film. The spectral light transmittance of this film at 300 to 400 nm is 2.
It was 0% or less.

Production of Protective Adhesive Film A heat-sensitive acrylic adhesive (trade name “ATH-50”, manufactured by Saiden Chemical Co., Ltd.) was formed on one surface of the substrate film obtained above.
0 ", solid content concentration 24%), and the thickness after drying is 30 μm.
Was applied and dried to produce a protective pressure-sensitive adhesive film.

(Comparative Example 1) 2- (2'-hydroxy-5'-methyl) -2H-benzotriazole (manufactured by Ciba-Geigy) was added to 100 parts by weight of the same soft vinyl chloride resin composition as in Example 1. 5 parts by weight are added and kneaded,
A 60 μm film was formed by calendering. The spectral light transmittance of this film at 300 to 400 nm was 2.0% or less. Then, a thermosensitive acrylic adhesive was applied to this film in the same manner as in Example 1 and dried to produce a protective pressure-sensitive adhesive film.

Example 2 Synthesis of copolymer of 2- (2'-hydroxy-5'-methacryloxyethylphenyl) -2H-benzotriazole and methyl methacrylate 2- (2'-hydroxy-5 ' -Methacryloxyethylphenyl) -2H-benzotriazole (manufactured by Otsuka Chemical Co., Ltd.) 30 parts by weight, methyl methacrylate 70 parts by weight and methyl ethyl ketone 200 parts by weight were placed in a separable flask, and a polymerization initiator azobisisobutyronitrile was placed. Was added with 1 part by weight, and then the atmosphere was replaced with nitrogen. Then, polymerize at 80 ° C. for 3 hours with stirring, and then add 1 to the obtained polymer solution.
0 times the amount of methanol was added to precipitate the polymer, which was filtered with a filter and dried in a vacuum oven at 50 ° C. for 5 hours to obtain a copolymer. When the molecular weight was measured by the GPC method, the weight average molecular weight in terms of polystyrene was 40,000.
Met.

Molding of base film 100 parts by weight of vinyl chloride resin (average degree of polymerization 1300),
To 100 parts by weight of a soft vinyl chloride resin composition consisting of 50 parts by weight of a plasticizer and 2 parts by weight of a metal-based stabilizer, 10 parts by weight of the above-obtained copolymer was added, kneaded, and calendered. To a 60 μm film. The spectral light transmittance of this film at 300 to 400 nm is 2.
It was 0% or less.

Production of Protective Adhesive Film A thermosensitive acrylic adhesive was applied to one surface of the substrate film obtained above in the same manner as in Example 1 and dried to produce a protective adhesive film.

Performance Test The protective adhesive films obtained in Examples 1 and 2 and Comparative Example 1 were used as samples for the following evaluations. Initial Adhesion Strength Test A sample cut into 25 mm x 100 mm was attached to a stainless steel plate, and a roller having a weight of 2 kg was reciprocated once for pressure bonding, and 15 minutes later, the speed was 300 mm / min for 1 minute.
The load when peeled in the direction of 80 degrees was examined, and the results are shown in Table 1.
It was shown to. Weather resistance test A sample cut into 25 mm x 100 mm was attached to a stainless steel plate, and a roller with a weight of 2 kg was reciprocated and crimped once, and then a weather resistance test device [Suga Test Instruments Co., Ltd., trade name "Ducycle Sunshine" Weather meter (WE
L-SUN-DC) ”], and after 100 hours, 2
Take out after 00 hours and 500 hours, 300mm
The load when peeled in the direction of 180 degrees at a speed of / min was examined, and the results are shown in Table 1.

[0024]

[Table 1]

Outdoor exposure test A sample (A4 size) was applied to color photographic printing paper (A4 size) using a hot roll laminator at a speed of 50.
The sample was adhered at 0 mm / min, a temperature of 40 ° C. and a roll pressure of 5 kg / cm ² , exposed to the south and exposed at an elevation angle of 45 ° (location: Shioe, Amagasaki City, Hyogo Prefecture), and after 1 year, the condition of the sample was observed. As a result, in the samples of Examples 1 and 2, neither discoloration of the color photographic printing paper nor breakage of the protective adhesive film was observed. However, in the sample of Comparative Example 1, some peeling occurred between the protective pressure-sensitive adhesive film and the color photographic printing paper due to migration of the ultraviolet absorber.

[0026]

EFFECT OF THE INVENTION The protective pressure-sensitive adhesive film of the present invention has the constitution as described above, and since a specific high molecular weight ultraviolet absorber is used, migration of the ultraviolet absorber from the base film is suppressed. The adhesive property of the adhesive layer is unlikely to deteriorate. Therefore, the protective pressure-sensitive adhesive film of the present invention is particularly suitable as a color-shifting protective pressure-sensitive adhesive film for outdoor use such as photographic film, photographic paper, and signs using posters, etc. against discoloration against sunlight, ultraviolet rays, rainwater and the like.

Claims (1)

[Claims] 1. A synthetic resin 1 capable of forming a transparent film.
2- (2'-hydroxy-5'-
A composition formed by adding 5 to 50 parts by weight of a copolymer of 5 to 50% by weight of methacryloxyethylphenyl) -2H-benzotriazole and 95 to 50% by weight of styrene or a (meth) acrylic ester is molded. A protective pressure-sensitive adhesive film comprising a pressure-sensitive adhesive layer laminated on one surface of the obtained base film.