JPH04142930A - Production of releasable anti-fogging film - Google Patents

Abstract

PURPOSE:To maintain an anti-fogging property on the face side and alleviate an adhesive force for an object on the back side, by coating or laminating, the face side of a transparent support film with a layer of a highly hydrophilic resin such as a surfactant-containing resin, and coating the back side with a resin which does not have a pressure sensitive adhesive property and has a high electrostatic capacity. CONSTITUTION:A layer of a highly hydrophilic resin such as a surfactant-containing resin is provided on the face side of a transparent support film 1 by coating or laminating, to form an anti-fogging layer 2. The back side of the film 1, namely, the surface to be brought into close contact with an objective surface, is coated with a resin layer 6 which does not have a pressure sensitive adhesive property and has a high electrostatic capacity. During storage before use, the antifogging layer 2 on the face side is covered with a protective film 4 in close contact therewith, and the high electrostatic capacity resin layer 6 on the back side is covered with a releasable film 5 in close contact therewith. At the time of sticking this anti-fogging film to the surface of an object such as a mirror, the film is stuck uniformly by gradually releasing the releasable film 5. At the time of using the object, the protective film 4 on the face side is removed.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial Field of Application The present invention is used to prevent fogging on the surfaces of mirrors, window glasses, etc., so that the antifogging function of the antifogging film applied to the surface may deteriorate.
The present invention relates to the production of an antifogging film that can be easily replaced in a short period of time in the event of discoloration or scratches.

(b) Conventional technology When thin water droplets adhere to the surface of particularly glossy substrates such as glass products and plastic products, they scatter light rays, causing a fogging phenomenon that can be applied to the lenses of sunglasses, cameras, etc., bathrooms, etc. It can be seen in mirrors, automatic military glass, window glass, etc.

In order to prevent these fogging phenomena, conventionally, a transparent film having antifogging properties was attached to the surface of these substrates to improve the antifogging effect.

As an anti-fog film, for example, as shown in Figure 2, a hydrophilic compound or a surfactant is applied to the surface of a film (hereinafter referred to as a support film) such as a strong polyester film with excellent transparency (polyethylene terephthalate CPET). By forming a coating film or a laminated film containing the film, it absorbs or adsorbs moisture, prevents water droplets from adhering to it, and prevents fogging, and is applied to the back side of the support film or to the surface of an object such as glass. An adhesive is applied to the surface to form an adhesive layer to improve adhesion to the surface of the object.

(c) Problems to be solved by the invention In the case of using the conventional anti-fog film as described above, the anti-fog function deteriorates after a certain period of time, although it varies depending on the usage environment. Due to scratches, discoloration, etc., the anti-fog film may need to be replaced.
At that time, the adhesive layer was not peeled off smoothly, and the adhesive remained on the surface of the object or the film itself was torn, resulting in extremely complicated work.

The present invention was completed as a result of research for the purpose of providing a method for manufacturing an anti-fog film that allows the work of reapplying the anti-fog film to be carried out easily and in a short time as described above. be.

(d) Means to solve the problem As shown in Figure 1, the supporting transparent film (1) needs to have strength and transparency to maintain the anti-fogging properties of the object, and depending on the use. Various plastic films can be used, such as single or OJ layers of polyester such as polyethylene terephthalate, polyolefin such as polyethylene and polypropylene, polyamide such as nylon, polycarbonate, polyacrylate, polystyrene, polyvinyl chloride, etc. You can use your body.

On the surface of the supporting transparent film (11), a highly hydrophilic resin layer such as a resin containing a surfactant is formed by coating or laminating to form the antifogging layer (2).The hydrophilic resin used for this For example, ζ can be coated with a hydrophilic compound such as a surfactant or polyethylene glycol, or a highly hydrophilic compound made of polyvinyl alcohol, polyacrylamide, polyacrylic acid, triacetate-1, gelatin, collagen, etc., or a derivative thereof. A method such as applying a solution of molecules is effective.Next, the back side of the support film (11, that is, the side that comes into close contact with the target surface) is formed by applying a non-adhesive resin N (6) that has a large electrostatic capacity. The present invention is characterized by a method for producing an antifogging film that contributes to improving the efficiency during repainting and has the resin layer (6) having a large electrostatic capacity as a constituent element.

As a resin layer with a large electrostatic capacity, for example, dioctyl phthalate-1-(DoP) or the like is added to a toluene solution of ethylene vinyl acetate copolymer resin (hereinafter referred to as EVA resin), as described in the examples below. It is also possible to make an emulsion by adding water to which a plasticizer or a hydrophilic compound such as glycerin has been added, and apply this to the back surface of the support film (1) to form a resin layer with a large electrostatic capacity.

As shown in Figure 1, the anti-fog film of the present application has a protective film (4) on the anti-fog layer (2) on the surface during storage before use.
The resin layer with high electrostatic capacitance on the back side (
6) is tightly coated with a release film (5), and when applied to the surface of an object such as a mirror, the release film (5) is peeled off and applied evenly to the surface of the object when used. Remove the protective film (4).

(e) Effect The anti-fog film produced by the production method according to the present invention does not absorb or adsorb moisture from the outside and form water droplets due to the hydrophilic layer such as a resin layer containing a surfactant on the surface. (Therefore, the incident light rays will not be diffusely reflected and cause fogging, and the resin layer with a large electrostatic capacity on the surface that is attached to the object such as a glass plate will adhere uniformly to the object surface due to the accumulated static electricity.) However, since it is originally a non-adhesive substance, it is difficult to peel it off when reapplying it. By reducing the physical resistivity of the resin, which has a large electrostatic capacitance, and thus reducing the electrostatic capacitance, the adhesion strength is weakened, making it easier to shorten the replacement work when the anti-fogging function of the film has deteriorated. Furthermore, the peeled film is dried and
It is also possible to restore the charging function by friction or other means and reuse it.

(f) Example A polyethylene terephthalate (PBT) film with a thickness of 50 μm was used as the supporting film, and a resin solution containing a surfactant was coated on the surface as an antifogging layer for about 1 hour.
0 to 50 μ) Dry, and add an appropriate amount of water to a solution of 100 parts of EVA dissolved in 100 parts of toluene and 30 parts of plasticizer (DOP) and 5 parts of glycerin and stir +
! The emulsion containing P was applied and dried to form an antifogging film as a resin layer with a large electrostatic capacity. In this case, the volume resistivity immediately after peeling off the release film on the resin layer surface, which has a large electrostatic capacitance, is 1.0 x 1013 Ω-C♂, and after being in close contact with the glass plate and exposed to 40°C steam for 30 minutes, it is 1.0 x 10
It was Ω-cm.

In addition, the anti-fog treatment layer on the surface is 2° right after the protective film is removed.

Similarly, after water absorption, it was 2.OX 10 Ω-cm3.

In addition, we conducted a comparative test with a conventional anti-fog film that adheres to the adhesive layer, and found that it could be immersed in steam at various temperatures for a short period of time.
There was no change in long-term antifogging properties, and the resin layer with a large electrostatic capacity according to the present invention was easily removable during reapplying, and the releasability of the film that had been applied for a long period of time was particularly good.

(g) Effects of the invention The method for producing an antifogging film having releasability according to the present invention is as follows:
The method of applying the film to the target object is different from that of conventional anti-fog films. A new invention that not only produces an anti-fog effect, but also makes it extremely easy to replace the adhesive in a short time when the anti-fog function deteriorates, discolors, scratches, etc. due to long-term use or overuse. It is.

[Brief explanation of drawings]

FIG. 1 shows an example of the present invention. 1 is a partially enlarged cross-sectional view of an example of an anti-fog film manufactured by a method for manufacturing an anti-fog film having jilting properties. FIG. 2 is a partially enlarged sectional view of the same conventional antifogging film. In the figure: 1 - - - Support film 2 - - Anti-fog treated layer 3 - - Adhesive layer 4 - Protective film 5 - Release film 6 ------
---One Electrostatic Capacity Large Resin Layer Co., Ltd.

Claims (1)

[Claims] A large hydrophilic resin layer such as a resin containing a surfactant is coated or laminated on the surface of the support transparent film,
By coating the back side with a non-adhesive resin with high electrostatic capacity, the hydrophilicity of the surfactant on the surface and the large electrostatic capacity on the back side maintain the anti-fogging properties of the front side and allow the back side to adhere to objects. A method for producing an anti-fog film characterized by reducing force.