JPH0531853A - Self adhesive anti-fogging sheet - Google Patents

Abstract

PURPOSE:To obtain a self-adhesive anti-fogging sheet not lowered in its transparency even if a long period of time is elapsed after bonding and susceptible to re-bonding by using a composition consisting an ethylene-vinyl acetate copolymer limited in the monomer ratio of ethylene and vinyl acetate, a specific vinyl chloride resin and a plasticizer as an self-adhesive. CONSTITUTION:In an anti-fogging sheet wherein an anti-fogging plastic layer is provided to one surface of a base sheet composed of transparent plastic and an self-adhesive is applied to the other surface thereof to apply release paper to the self-adhesive layer, as the self-adhesive, a composition consisting of 100 pts.wt. of a synthetic resin wherein vinyl chloride is subjected to the graft polymerization with an ethylene/vinyl acetate copolymer wherein the monomer ratio of ethylene and vinyl acetate is 30-60% : 70-40% so that the ratio of the copolymer and the monomers becomes 50-75: 50-25% and 20-75 pts.wt. of a plasticizer is used. By this constitution, the sheet can be bonded without generating the lowering of the transparency or appearance inferiority of the sheet accompanied by re-bonding at the time of execution.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improvement of an antifogging sheet having self-adhesiveness or adhesiveness.

[0002]

2. Description of the Related Art Anti-fog sheets are often attached to automobile windows, rearview mirrors, bathroom mirrors, etc. so that their surfaces do not fog. In general, an antifogging sheet is one in which an antifogging layer is provided on one surface of a transparent base material sheet, and an adhesive is applied to the other surface of the base material sheet for the convenience of construction and storage. Most of them are coated with release paper.

The antifogging sheet is required to be transparent even after construction. However, when using an adhesive that is commonly used as a wallpaper or the like, dust and fingerprints are attached to the adhesive layer and the transparency is impaired. In order to prevent this, it is sufficient to apply a diluted surface active agent solution, and it is necessary to have skill to perform such an operation. Further, if a commonly used pressure-sensitive adhesive is used, the transparency of the pressure-sensitive adhesive layer will be impaired after peeling, and the sheet cannot be reattached.

As a technique for easily attaching the sheet to the sheet without impairing the transparency, 20 to 50 parts of a plasticizer is added to 100 parts by weight of a synthetic resin obtained by graft-polymerizing an ethylene-vinyl acetate copolymer with a vinyl chloride monomer. 75 parts by weight of a simple adhesive material exhibiting self-adhesiveness, and 5 to 150 parts by weight of a tackifier if necessary to give adhesiveness (Japanese Patent Publication No. 51-28102). issue)
It has been known. However, it has been experienced that, even after a long time has passed since the antifogging sheet was applied to this simple adhesive material, the transparency was lowered and the adhesive strength of the pressure-sensitive adhesive was increased, making it difficult to peel it off. The difficulty of peeling not only requires a strong force, but also results in the pressure-sensitive adhesive remaining on the adherend to which the anti-fog sheet is attached, and sometimes the adherend being damaged.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a pressure-sensitive adhesive anti-fogging sheet which does not deteriorate in transparency even after a long period of time after application and can be easily peeled off and re-adhered. It is in.

[0006]

The adhesive antifogging sheet of the present invention comprises a transparent plastic substrate sheet provided with an antifogging plastic layer on one surface thereof, and coated with an adhesive agent on the other surface thereof for peeling. In the anti-fog sheet on paper, as an adhesive,
The monomer ratio of ethylene and vinyl acetate is 30 to 60
%: 70-40% ethylene-vinyl acetate copolymer with vinyl chloride and a copolymer to monomer ratio of 50.
~ 75%: A composition comprising 100 parts by weight of a synthetic resin graft-polymerized to be 50 to 25% and 20 to 75 parts by weight of a plasticizer, preferably 25 to 29 parts by weight is used. .

The plasticizer may be similar to the plasticizer for polyvinyl chloride. For example, phthalic acid ester-based, aliphatic dibasic acid ester-based, inorganic acid ester-based, polyester-based, and epoxy-based plasticizers. If the amount of the plasticizer is too large, the plasticizer will migrate to the adherend, and if it is too small, the adhesive strength will be insufficient. Therefore, the content of the plasticizer was set to the range of 20 to 75 parts by weight. In particular, when the compounding amount is in the range of 25 to 29 parts by weight, the work of reattaching the sheet is easy and the appearance defect due to the reattachment can be eliminated, so this range is preferable.

It is preferable to add an additive to the pressure-sensitive adhesive to prevent deterioration due to ultraviolet rays. As such additives, various types such as tin-based, lead-based, and barium-based additives are known, and any of these may be appropriately selected and used. The content of the additive is generally about 10% by weight, but the content can be reduced by adding a reaction accelerator. For example, when 1% by weight of fatty acid is contained in the adhesive as a reaction accelerator, the content of the additive is also 1%.
Weight% is sufficient.

Since the above-mentioned composition has an adhesive strength of a degree of self-adhesion rather than adhesiveness, when it is desired to have a more definite adhesive strength, it is used as a tackifier. Rosin or modified rosin derivative, terpene modified product, phenolic resin graft polymerized resin 100
Blending is performed in the range of 5 to 150 parts by weight per part by weight to increase the adhesive strength.

In addition, stabilizers, lubricants and the like may be added within a range not impairing transparency.

The pressure-sensitive adhesive layer may be formed by a known coating means, and its thickness is suitably 5 to 15 μm.

As the release paper, a film or paper of various commonly used plastics typified by polyester, coated with a release agent such as silicone, may be used.

The transparent plastic used for the substrate sheet can be selected arbitrarily. For example, polyester, polypropylene, polycarbonate, polyvinyl chloride, acrylic resin, polyamide, ionomer, polystyrene, polyurethane, ABS resin, There are sheets of ethylene-vinyl acetate copolymer, cellulose resin and the like. By subjecting one or both sides of the base sheet to an easy-adhesion treatment such as primer treatment or corona treatment, an anti-fog sheet in which the base sheet and the pressure-sensitive adhesive layer and / or the anti-fog layer are firmly adhered is formed. can get.

There are several known methods for forming an anti-fog plastic layer, and any of them is available. 1) Apply a hydrophilic substance such as polyethylene glycol or a water repellent substance such as silicone. 2) A hydrophilic substance or a water-repellent substance is dispersed in a polymer binder and applied to form a coating film. 3) A solution of a hydrophilic polymer such as polyvinyl alcohol, gelatin, cellulose or a derivative thereof is applied and dried to form a hydrophilic coating film. 4) A triacetyl cellulose film is formed and saponified.

When forming a thick film antifogging layer, the following method may be used. That is, an ionizing radiation curable resin,
A composition in which a hydrophilic monomer, a surfactant and, if necessary, a cross-linking agent are mixed is applied, and the composition is irradiated with ultraviolet rays or electron beams to be cured. Typical examples of ionizing radiation curable resins are unsaturated polyesters or urethane acrylates, and typical examples of hydrophilic monomers are hexyl ethyl methacrylate or polyethylene glycol diacrylate. The surfactant may be ionic or nonionic, and a known monomer having two or more crosslinkable functional groups may be used as the crosslinker.

The thickness of the antifogging plastic layer is 1 μm.
As described above, it is 30 μm or more depending on the application. Thickness is 1
If it is less than μm, the saturated water absorption is insufficient and the antifogging effect is poor.

[0017]

The pressure-sensitive adhesive anti-fog sheet of the present invention enjoys the advantage of the above-mentioned invention that it can be easily applied, and the one in which the amount of the plasticizer compounded in the pressure-sensitive adhesive is limited to 25 to 29 parts by weight can be used at the time of peeling. It excels in light peeling and smoothness, and the sheet can be attached without deterioration of the transparency of the sheet and poor appearance due to reattachment during construction.

The adhesive containing an additive for preventing deterioration due to ultraviolet rays can be used even after a long period of time after application.
Since lightness and smoothness of peeling are maintained, it can be easily peeled off.

By subjecting one or both sides of the base sheet to an easy-adhesion treatment, the base surface and the adhesive layer and / or
It adheres firmly to the antifogging layer and can be peeled off without leaving an adhesive on the adherend to which the antifogging sheet is attached.

[0020]

Example 1 100 parts by weight of urethane acrylate, 2-
Hydroxyethyl methacrylate (hydrophilic monomer) 10
0 parts by weight, 10 parts by weight of neopentyl glycol diacrylate (crosslinking agent), and the surfactant "Emulgen 10".
5 parts by weight of 6 "(manufactured by Kao Corporation) were uniformly mixed and heated to adjust the viscosity to 500 cps. This composition was roll-coated on a polyester base sheet having a thickness of 50 μm and irradiated with an electron beam to prepare an antifogging sheet having an antifogging layer having a thickness of 50 μm.

Resin 100 prepared by graft-polymerizing 60% of ethylene-vinyl acetate copolymer with 40% of vinyl chloride monomer.
Dioctyl phthalate (plasticizer) was blended in 11 parts by weight, 25 parts by weight, 29 parts by weight, 33 parts by weight, 42 parts by weight and 80 parts by weight with 10 parts by weight of the tin-based additive. Six types of adhesives were prepared.

An adhesive anti-fog sheet was produced using each adhesive. The obtained adhesive anti-fog sheet has a side of 12
It was cut into a square of cm and the following evaluation test was performed.

1. Influence of fingerprints The release paper was peeled off from the adhesive anti-fog sheet, and the adhesive layer was pressed with a finger to give a fingerprint. The pressure-sensitive adhesive anti-fog sheet was placed on a horizontally placed glass plate with the pressure-sensitive adhesive layer facing downward, and lightly pressed with a soft cloth to be stuck. With respect to the obtained product, the effect on the transparency of the fingerprints attached to the adhesive layer was observed. In the evaluation, the one that did not affect the transparency after the fingerprint was A, the one that was clouded was B, and the one that was clearly recognized as a fingerprint was C.

2. Ease of Evacuation of Bubbles A pressure-sensitive adhesive antifogging sheet from which a release paper had been peeled off was attached to a glass plate so that air bubbles could be formed. The air was released by applying pressure from the center toward the outside. The case where air could be removed by eliminating air bubbles was evaluated as A, and the case where air could not be removed was evaluated as C.

3. Peeling off from adherend One minute after the above air bleeding, the adhesive anti-fog sheet was slowly peeled off diagonally from the glass plate.
At this time, the peeling resistance and the smoothness of peeling were evaluated. Peeling resistance was evaluated as A, where little resistance was felt, B when a little resistance was felt, C as heavy peeling, and smoothness of peeling was evaluated as smooth peeling without sound. A was a noise when peeled, and C was a noise. The traces of air bubbles on the peeled sheet were observed, and when the trace was completely disappeared, A was evaluated, and when the trace was not deleted, C was evaluated.

The results of each test are summarized in Table 2. In Table 2, the compounding amount of the plasticizer is parts by weight.

[0027] Table 2 over door plasticizer amount Conclusions disconnect only of resistance smoothness of the pressure-sensitive anti-fogging the pressure-sensitive adhesive of the variable fingerprint of the air of peeling away at the bubble at the time of peeling Conclusion No.11 11 A A A C A No. 12 25 A A A A A A No. 13 29 A A A A A A No. 14 33 A A B A A A No. 15 42 B C B A C No. 16 80 C C C A C These From the result of N, which is the adhesive antifogging sheet of the present invention
o. 12 to No. No. 15 sheet, especially No. 15 in which the amount of the plasticizer compounded was in a suitable range. 12 and No. The sheet of No. 13 showed good physical properties, but No. 13 with a small plasticizer content. The sheet of No. 11 lacked the smoothness at the time of peeling and contained a large amount of the plasticizer. It can be seen that the sheets of 16 did not disappear after fingerprints and bubbles, were hard to release air, and were peeled off heavily.

[0028]

Example 2 The following three types of adhesives were prepared.

Adhesive (a) An adhesive in which 25 parts by weight of dioctyl phthalate (plasticizer) is mixed with 100 parts by weight of a resin obtained by graft-polymerizing 40% of vinyl chloride monomer in 60% of ethylene-vinyl acetate copolymer.

Adhesive (b) Adhesive (b) containing a resin and a plasticizer as in the adhesive (a) and containing 1% by weight of a tin-based additive and 1% by weight of a fatty acid as an accelerator. Agent.

Adhesive (c) An adhesive containing a resin and a plasticizer as in the adhesive (a) and containing 10% by weight of a tin-based additive.

The above three kinds of pressure-sensitive adhesives were each diluted with a 1: 1 mixed solvent of methyl ethyl ketone and toluene until the solid content became 20%. This pressure-sensitive adhesive was roll-coated on a 25 μm-thick release paper “Film Separator BK type” (manufactured by Toyo Metallizing Co., Ltd.) and dried at 100 ° C. for 1 minute to provide a 10 μm-thick pressure-sensitive adhesive layer.

A polyester resin-based primer was applied on the surface of the base material of the anti-fog sheet to a thickness of 0.5 μm, and the release paper was applied with the pressure-sensitive adhesive layer sandwiched between the primer and the adhesive paper. An anti-fog sheet was manufactured. The adhesive anti-fog sheet (No. 1) using the adhesive (a) is a conventional adhesive anti-fog sheet, and the adhesive anti-fog sheet (No. 2) and the adhesive (c) using the adhesive (b) are used. The adhesive anti-fog sheet (No. 3) using () is the adhesive anti-fog sheet of the present invention.

Each adhesive anti-fog sheet was cut into a width of 25 mm, the release paper was peeled off, and a rubber roll (line pressure 2 kg) was used.
Was used to adhere to a glass plate. These glass plates were left at room temperature for 24 hours (condition 1), then subjected to an acceleration test with a fade meter for 50 hours (condition 2), and then subjected to an acceleration test with a fade meter for 100 hours (condition 3). ), 300mm from the glass plate with the adhesive anti-fog sheet
The adhesive strength when peeled at an angle of 180 ° at a speed of / min was measured. The results are shown in Table 1.

Table 1 Adhesive anti-fog sheet condition 1 condition 2 condition 3 No. 1 (comparative example) 10 1400 1400 No. 1 2 (Example) 10 120 180 No. 3 (Example) 10 35 60 It can be seen that the pressure-sensitive adhesive anti-fog sheet of the present invention has a smaller degree of increase in the adhesive force as compared with the conventional pressure-sensitive anti-fog sheet.

[0036]

[Example 3] The pressure-sensitive adhesive (b) layer and release paper were laminated in the same manner as in Example 1 except that the primer layer was not provided on the base sheet side of the anti-fog sheet, and the adhesive anti-fog of the present invention was obtained. A sheet (No. 4) was manufactured.

As a base sheet, a polyester sheet "HP-7" (manufactured by Teijin) having a thickness of 50 μm and subjected to easy adhesion treatment
Was used, and an antifogging sheet having an antifogging layer on its untreated surface was prepared. Using this anti-fog sheet, the pressure-sensitive adhesive (b) layer and release paper were laminated in the same manner as above to produce the adhesive anti-fog sheet (No. 5) of the present invention.

Adhesive anti-fog sheet No. 1 of the present invention. 2, No.
4 and No. 5 was cut into a width of 25 mm and attached to a glass plate in the same manner as in Example 1.

These glass plates were heated at a temperature of 70 ° C. to 70 ° C.
After leaving for a period of time, remove the adhesive anti-fog sheet from the glass plate 300 times.
The adhesive layer was peeled off at an angle of 180 ° at a speed of mm / min, and the adhesive layer at that time was observed. N without easy adhesion treatment
o. Although the pressure-sensitive adhesive layer of the pressure-sensitive adhesive anti-fog sheet of No. 4 was floated, there was no change in the pressure-sensitive adhesive layers of the other pressure-sensitive adhesive anti-fog sheets.

A glass plate similar to the above with the adhesive antifogging sheet adhered thereto was subjected to an acceleration test with a fade meter for 50 hours, and the adhesive layer when the adhesive antifogging sheet was peeled off was observed in the same manner as above. No. In the adhesive anti-fog sheet of No. 4, part of the adhesive was attached to the glass plate, but the other adhesive anti-fog sheets were peeled off cleanly.

Adhesive anti-fog sheet No. 1 with the release paper peeled off
2, No. 4 and No. 5 was folded in half with the pressure-sensitive adhesive layer inside and pressed using a rubber roll (linear pressure 2 kg). 1 minute later, 180 at a speed of 300 mm / min
It was peeled off at an angle of ° and the adhesive layer at that time was observed. No. In the pressure-sensitive adhesive anti-fog sheet of No. 4, part of the pressure-sensitive adhesive moved to the pressure-sensitive adhesive layer on the opposite side and remained, but the other pressure-sensitive adhesive anti-fog sheets were peeled off without such a phenomenon.

[0042]

EFFECTS OF THE INVENTION The adhesive anti-fog sheet of the present invention can be attached to an adherend without impairing transparency during application, and can be easily peeled off even after a long period of time. It can be fixed. The one to which an additive for preventing deterioration due to ultraviolet rays is added has less deterioration of the pressure-sensitive adhesive, and these effects are high.

Claims (4)

[Claims] 1. A transparent plastic substrate sheet having an antifogging plastic layer provided on one surface thereof, the other surface of which is coated with an adhesive agent, and release paper is applied thereto. The monomer ratio of ethylene and vinyl acetate is 3
100 parts by weight of a synthetic resin obtained by graft-polymerizing vinyl chloride to an ethylene-vinyl acetate copolymer of 0 to 60%: 70 to 40% so that the ratio of the copolymer and the monomer is 50 to 75%: 50 to 25%, And a plasticizer 20 to 7
An adhesive anti-fog sheet, characterized in that a composition comprising 5 parts by weight is used. 2. The pressure-sensitive adhesive anti-fogging sheet according to claim 1, wherein the pressure-sensitive adhesive contains an additive for preventing deterioration due to ultraviolet rays. 3. The adhesive antifogging sheet according to claim 1, wherein the amount of the plasticizer compounded in the adhesive is 25 to 29 parts by weight. 4. The pressure-sensitive adhesive antifogging sheet according to claim 1, wherein the base sheet has been subjected to an easy-adhesion treatment on one side or both sides.