JPH0753930A - Protective adhesive film - Google Patents

Abstract

PURPOSE:To obtain a protective adhesive film which enables easy removal of the air present between the film stuck to a sign board and the board and hence does not impair the appearance of the board by forming an adhesive layer contg. a microspherical self-adhesive. CONSTITUTION:An adhesive layer comprising a microspherical self-adhesive alone or together with a binder is formed on one side of a transparent substrate film. The self-adhesive is pref. an acrylic, has pref. a particle size of 5-50mum and is produced by, e.g. polymerizing monomers in soln., dispersing the resultant copolymer in water to provide an aq. suspension, and removing water and the solvent with a centrifugal separator. As the binder is used a self-adhesive or a synthetic resin binder.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a protective adhesive film for protecting signboard media such as photographic film, photographic paper and posters from sunlight, ultraviolet rays, rainwater and the like.

[0002]

2. Description of the Related Art Photographic film, photographic paper,
Although posters and the like are widely used, since photographic film and photographic paper are coated with a silver salt emulsion, they are susceptible to discoloration under the influence of sunlight and ultraviolet rays, especially when used outdoors. Also, printed materials such as posters may fade or discolor when used outdoors for a long time. Further, outdoors, signboard media such as photographic film, photographic paper, and posters are easily damaged due to the effects of rainwater, wind, dust, etc. and intentional vandalism. Even if it is used indoors, it may cause discoloration or damage, although it is not as good as outdoor use.

Conventionally, a protective adhesive film has been devised in order to prevent discoloration or breakage of the signboard medium, and in particular, in order to prevent discoloration due to sunlight or ultraviolet rays, a film containing an ultraviolet absorber is used as a base material. The protective adhesive film used was used.

The protective adhesive film has a structure in which a transparent plastic film is used as a base material and an adhesive layer is formed on one surface of the transparent plastic film. Generally, the adhesive is applied uniformly without voids. As a result, air is left at the adhesive interface when the protective adhesive film is applied to the signboard medium while being pressed by a press stand, laminator roll, etc., or heated if necessary, so that the letters and patterns of the signboard medium, etc. The appearance of is likely to be impaired. That is, since the portion where the air remains looks like marbling, there is a problem in that the basic function of the signboard medium, which is mainly intended for advertisements, to be clearly and easily seen is greatly impaired.

As one means for solving this problem, a method has been adopted in which a plastic film having fine holes for air venting is used as a base material. In the case of this method, the hole after performing the purpose of venting air,
It is blocked by the flow of the adhesive due to pressure or heat during application, or if a thermoplastic plastic film is used, the heating during application causes the plastic film to close the holes and It is said that it will not survive.

However, in reality, it is difficult to completely close all the holes, and in the case of outdoor use, rainwater may invade from the holes left unclosed to damage the signboard medium,
Problems such as sunlight and UV rays entering the sign medium and discoloring remain. Further, even in the case of indoor use, there still remains a problem that the signboard medium is contaminated or discolored due to infiltration of dust or the like.

As another means, in order to protect the signboard medium, a signboard medium such as a poster is sandwiched between a substrate having an adhesive layer on the front surface and a transparent protective plate having an adhesive layer on the back surface. A poster panel having an adhesive structure has been proposed (Japanese Utility Model Publication No. 55-84670), but this method also does not solve the problem that air remains at the adhesive interface and the appearance of the signboard medium is impaired.

[0008]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art and provides a protective adhesive film which can easily eliminate air at the adhesive interface and does not impair the appearance of a signboard medium. With the goal.

[0009]

The protective adhesive film of the present invention requires that an adhesive layer containing a microspherical pressure-sensitive adhesive is formed on one surface of a substrate film, which results in the above-mentioned. The purpose is achieved.

As shown in FIG. 1, the protective adhesive film of the present invention comprises an adhesive layer 4 containing a microspherical pressure-sensitive adhesive 2 formed on one surface of a base film 1.

The type of film used as the base material of the protective adhesive film of the present invention is not particularly limited, and transparent plastic films such as polyethylene terephthalate, stretched polypropylene, polycarbonate, polyethylene and soft vinyl chloride can be used. It is preferably used.

The thickness of the base film 1 is not particularly limited, but is preferably about 10 to 100 μm, and more preferably about 30 to 70 μm.

The adhesive layer 4 in the protective adhesive film of the present invention is formed by coating the microspherical pressure-sensitive adhesive 2 alone or together with the binder 3 on one surface of the base film 1.

Since the adhesive layer 4 contains the microspherical pressure-sensitive adhesive 2, the surface of the adhesive layer 4 becomes uneven, and this serves as an air circulation path to attach the protective adhesive film to the signboard medium. Sometimes the air at the adhesive interface is easily eliminated.

The adhesive layer 4 can be formed by only the microspherical pressure-sensitive adhesive 2, but generally it is more preferable to use the microspherical pressure-sensitive adhesive 2 and the binder 3 together to form the adhesive layer 4. preferable.

By using the binder 3 in combination, it is possible to improve the adhesion of the microspherical pressure-sensitive adhesive 2 to the base film 1 and the adhesion of the microspherical pressure-sensitive adhesives 2 to each other. Further, as shown in FIG. 1, by appropriately covering the surface of the microspherical pressure-sensitive adhesive 2 with the binder 3, it becomes possible to control the adhesive force of the protective adhesive film.

The type of the binder 3 is not particularly limited, and rubber-based, acrylic-based, silicon-based, etc. adhesives, acrylic-based, epoxy-based, vinyl ether-based, etc. synthetic resin-based binders are preferred. Used for.

The type of the microspherical pressure-sensitive adhesive 2 that must be contained in the adhesive layer 4 is not particularly limited, but an acrylic microspherical pressure-sensitive adhesive 2 is preferable.

The particle size of the fine spherical pressure-sensitive adhesive 2 is not particularly limited, but is preferably in the range of about 5 to 50 μm. If the particle size of the microspherical pressure-sensitive adhesive 2 is less than about 5 μm, the air exclusion effect when attaching the protective adhesive film to the signboard medium becomes poor, and conversely, if it exceeds about 50 μm, the adhesion area with the signboard medium becomes small. Therefore, it becomes difficult to obtain a proper adhesive force.

The 180 ° angle peel strength of the protective adhesive film of the present invention having the adhesive layer 4 to the cold rolled stainless steel plate is preferably in the range of about 500 to 2000 g / 25 mm width.

The compounding ratio of the fine spherical pressure-sensitive adhesive 2 and the binder 3 constituting the adhesive layer 4 is not particularly limited, but
Microspherical pressure-sensitive adhesive 2 / binder 3 = 100 parts by weight / in terms of solid content /
It is preferably in the range of about 0 to 50 parts by weight. The compounding ratio of the binder 3 to 100 parts by weight of the fine spherical adhesive is 50.
When the amount exceeds about parts by weight, the unevenness of the surface of the adhesive layer 4 caused by the fine spherical pressure-sensitive adhesive 2 decreases, so that the function of eliminating air at the adhesive interface deteriorates.

When the binder 3 has tackiness, the adhesive layer 4 becomes a pressure-sensitive adhesive layer, and when the binder 3 does not have tackiness, the range of the above compounding ratio is obtained. At the inner,
When the compounding ratio of the binder 3 to the microspherical adhesive 2 is small, the adhesive layer 4 becomes a pressure sensitive adhesive layer, and when the compounding ratio of the binder 3 to the microspherical adhesive 2 is large, the adhesive layer 4 is heat-sensitive adhesive. It becomes the agent layer.

The coating thickness of the adhesive layer 4 formed on one surface of the base film 1 is not particularly limited, but is preferably in the range of 10 to 50 μm in terms of solid content. However, it is more preferable that the thickness is in the range of about 20 to 40 μm.

The coating thickness of the adhesive layer 4 is 10 μm in terms of solid content.
If it is less than the range, coating becomes difficult and the adhesive strength becomes weak. On the other hand, if it exceeds about 50 μm, excessive coating will result in high cost.

The protective adhesive film of the present invention is, for example,
The product is made into a roll with a width of 1200 mm and a length of 50 to 100 m. Therefore, it is necessary to prevent the adhesive layer 4 from adhering to the non-adhesive layer surface of the base film 1, but the method is to apply a release agent to the non-adhesive layer surface of the base film 1 and release it. A method of applying a treatment may be used, or a method of using the release paper 5 to attach the release-treated surface of the release paper 5 to the adhesive layer 4 of the protective adhesive film may be used.

[0026]

The protective adhesive film obtained by the present invention is
Since the adhesive layer contains a microspherical pressure-sensitive adhesive, the surface of the adhesive layer is uneven, and there is an air flow path,
When it is attached to the signboard medium, the air at the adhesive interface can be easily removed, and the signboard medium can be protected for a long period of time without damaging the appearance. Further, it is not necessary to provide holes in the base film for removing air.

[0027]

EXAMPLES In order to explain the present invention in more detail, examples will be given below. In the examples, "part" is "part by weight".
Means

(Example)

( 1) Preparation of protective adhesive film The base film 1 contains a benzotriazole-based ultraviolet absorber, has a spectral light transmittance of not more than 2.0% at 300 to 400 nm, and has a thickness of 60 μm and is made of soft chloride. A vinyl film was prepared.

Next, butyl acrylate and acrylic acid 2-
Solution-copolymerized mixed monomers such as ethylhexyl, styrene, vinyl acetate, and vinyl propionate, and the resulting solution-copolymerized product is dispersed in water to prepare an acrylic microsphere adhesive 2
A water suspension of was prepared. Then, dehydration and solvent removal were carried out with a centrifuge to obtain an acrylic fine spherical adhesive 2 having an average particle diameter of 25 μm.

Further, as a binder 3, an acrylic solvent type pressure sensitive adhesive "SKDyne 1720" (solid content 45
%, Manufactured by Soken Chemical Industry Co., Ltd.) and 1 part of a cross-linking agent "Coronate L-55E" (manufactured by Nippon Polyurethane Co., Ltd.) per 100 parts of acrylic solvent type pressure sensitive adhesive were used, and the above-mentioned acrylic microspheres in solid content ratio 100 parts of the pressure-sensitive adhesive was mixed with 30 parts of the acrylic solvent-based pressure-sensitive adhesive, and the pressure-sensitive adhesive containing the acrylic microspherical pressure-sensitive adhesive 2 (solid content: 75
%) Was obtained.

The pressure-sensitive adhesive containing the obtained acrylic microspherical pressure-sensitive adhesive 2 was applied and dried on one surface of the base film 1 so that the coating thickness of the solid content was 30 μm, and then peeled off. It was attached to the release-treated surface of the paper 5 and wound on a paper core having an inner diameter of 3 inches to obtain a protective adhesive film having a width of 1200 mm and a length of 50 m.

( 2) Evaluation Table 1 shows the results of evaluation of the adhesive strength, sticking property and appearance of the protective adhesive film thus obtained after one year.

Adhesion : According to JIS Z-0237 "Adhesive tape / adhesive sheet test method", a protective adhesive film cut into a width of 25 mm and a length of 150 mm has a thickness of 2.
Bonding length 100 mm to 0 mm cold rolled stainless steel plate
And then left in an atmosphere of 23 ° C.-65% RH for 24 hours, and then, in that atmosphere, using a Shopper type tensile tester, a 180-degree peeling strength (g / 25 mm) at a pulling speed of 300 mm / min. Was measured.

[0035] Paste of: fresh green mountain landscape height 1200mm that contains as a pattern, a color photographic paper having a width of 2000mm as billboard media, paste the adhesive layer 4 of the protective adhesive film on the photo surface The adhesiveness was evaluated by observing the state of air remaining at the adhesive interface after attachment and the appearance of the signboard medium. The laminator heat roll was used for sticking, the roll temperature was 40 ° C, and the roll pressure was 5 kg.
/ Cm ² and roll peripheral speed of 500 mm / min.

Appearance after 1 year : The signboard medium to which the protective adhesive film prepared by the evaluation of the sticking property was stuck was left outdoors, and the appearance of the signboard medium and the protective adhesive film after 1 year was observed. .

(Comparative example)

In the production of the protective adhesive film, 100 parts of the acrylic solvent type pressure sensitive adhesive "SKDyne 1720" was used as an adhesive, and the crosslinking agent "Coronate L-55" was used.
A mixture of 1 part of "E" is used as an acrylic microsphere adhesive 2
A protective adhesive film was obtained in the same manner as in Example except that the above was used without mixing.

Table 1 shows the results of evaluation of the adhesive strength, sticking property, and appearance after 1 year of the resulting protective adhesive film in the same manner as in the examples.

[0040]

[Table 1]

[0041]

As described above, the protective adhesive film according to the present invention can easily eliminate the air at the adhesive interface when it is attached to a signboard medium, so that the signage medium is not damaged at all. Is to protect the long term reliably.

[0042]

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a protective adhesive film.

[0001]

[Explanation of symbols]

 1 Base Film 2 Microspherical Adhesive 3 Binder 4 Adhesive Layer 5 Release Paper

Claims (1)

[Claims] 1. A protective adhesive film, wherein an adhesive layer containing a microspherical pressure-sensitive adhesive is formed on one surface of a base film.