JP2000284108A - Resin mirror and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the generation of a spark on a reflective film in corona discharge treatment and to obtain a resin mirror free from a flaw and a burnt deposit and less liable to contamination by forming a photocatalyst layer before the formation of the reflective film. SOLUTION: The front side of a substrate is coated with a hard coat layer and heat-treated. The surface of the hard coat layer is subjected to corona discharge treatment, coated with photocatalyst-containing chemicals and heat- treated to form a photocatalyst layer. A reflective film is then formed on the rear side of the substrate by the vapor deposition of aluminum or another method. In order to enhance the adhesion of the hard coat layer to the substrate, a primer layer may be disposed between the substrate and the hard coat layer. The objective resin mirror comprises a resin such as an acrylic or polycarbonate resin. The hard coat layer is a coating film having siloxane bonds as the skeleton obtained by using a silicone resin such as an organopolysiloxane as a coating film forming element. The photocatalyst substitutes hydroxyl groups for organic groups bonding to silicon atoms of the silicone resin and forms an adsorbed water layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin mirror, and more particularly, to a road mirror installed on a road or the like that is heavily contaminated with smoke or exhaust gas.

[0002]

2. Description of the Related Art At present, resin mirrors are widely used in terms of weight reduction and low cost. In the field of road materials, road mirrors are used at intersections and turns with poor visibility for the purpose of traffic safety and safety management. However, they are contaminated by soot and soot in tires of automobiles, dust from tires, soot from roads, etc., giving an unpleasant impression, impairing the scenery of the roads and making the reflected images unclear. On the other hand, as for the photocatalyst, as disclosed in Japanese Patent No. 275647, a high degree of hydrophilicity is exhibited by photoexcitation,
Dirt can be washed away by rainfall etc. (Self-cleaning
It is known that it is possible to prevent adhesion dirt.

[0003]

In order to prevent the reflection image from being obscured due to dirt on the road mirror, it is conceivable to apply the photocatalyst. There is. When the photocatalyst layer is formed on the surface of the substrate, an intermediate layer is provided between the substrate and the photocatalyst layer in order to prevent the substrate from being oxidized and deteriorated by the photocatalyst layer. When a hard coat is used for the intermediate layer, it is necessary to perform a corona discharge treatment on the surface of the hard coat layer in order to improve the adhesion between the hard coat layer and the photocatalyst layer. However, when a corona discharge treatment is performed on a resin mirror having a metal reflection film formed on the back surface of the base material,
There is a problem that a spark is generated and the reflective film is burnt. SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a resin mirror which is less likely to be stained and a method for manufacturing the same.

[0004]

In order to achieve the above object, according to a first aspect of the present invention, there is provided a first step of forming a hard coat layer and a second step of performing a corona treatment on the hard coat layer. There is provided a method for manufacturing a resin mirror including a second step, a third step of forming a photocatalytic layer, and a fourth step of forming a reflective film.

In the second invention, a first step of forming a hard coat layer, a second step of performing a corona treatment on the hard coat layer, and a third step of forming a photocatalytic layer And a fourth step of performing a bending process and a fifth step of forming a reflective film.

In the third invention, a first step of forming a hard coat layer, a second step of performing a corona treatment on the hard coat layer, and a third step of forming a photocatalytic layer And a fourth step of forming a reflective film, and a fifth step of performing a bending process.

In a fourth aspect, a first step of performing bending, a second step of forming a hard coat layer, and a third step of performing a corona treatment on the hard coat layer are provided. And a fourth step of forming a photocatalyst layer and a fifth step of forming a reflective film.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for forming a photocatalyst layer on a resin mirror will be described below. First, a hard coat is applied to the surface of the substrate on which the reflective film has not been processed, and a heat treatment is performed. next,
Corona discharge treatment is performed on the surface of the hard coat layer. further,
A photocatalyst-containing chemical is applied and heat treatment is performed. Finally,
A reflective film is formed on the back surface on which the photocatalyst layer is formed by aluminum deposition or the like. Incidentally, a primer layer may be provided between the substrate and the hard coat layer in order to improve the adhesion between the substrate and the hard coat layer. Generally, resin mirrors are bent, and in order to perform corona treatment efficiently and easily,
After forming the photocatalyst layer, it is preferable to perform bending.
In another preferred embodiment, the photocatalyst layer may be formed after bending. Alternatively, the reflection film can be processed after forming the photocatalyst layer using a base material that has been subjected to bending processing in advance.

The term "resin mirror" as used herein refers to a mirror made of a resin such as acryl or polycarbonate.
There are road mirrors, car door mirrors, room mirrors, and design mirrors.

The term "hard coat layer" as used herein means that the organopolysiloxane is a main component, and a bifunctional, trifunctional, tetrafunctional silicone resin, silica sol, silane coupling or the like is used as a film forming element, or It refers to a coating film having a siloxane bond as a skeleton formed by applying a silicone precursor as a coating film forming element and applying and curing them. The method of forming the hard coat layer is, for example, a method in which a spray
Coating method, dip coating method, flow coating
It is performed by applying a hard coat by a method such as a coating method, a spin coating method, a roll coating method and the like, and performing a heat treatment at a temperature of about 150 ° C. or less.

The photocatalyst referred to here is a photocatalyst capable of replacing an organic group bonded to a silicon atom of a silicone resin with a hydroxyl group by a reaction through holes or conduction electrons generated by photoexcitation of electrons in a valence band. Or, to impart a polarity, refers to those having the ability to form an adsorbed water layer, more specifically, anatase type titanium oxide, rutile type titanium oxide, tin oxide, zinc oxide, bismuth trioxide, Tungsten trioxide, ferric oxide, strontium titanate and the like can be suitably used. The method of forming the photocatalyst layer is, for example,
A photocatalyst layer is applied to the surface of the base material by a method such as spray coating, dip coating, flow coating, spin coating, roll coating, etc., and about 150 ° C. or less. By heat treatment at a temperature of

The term "corona discharge treatment" as used herein refers to a treatment for modifying the surface of a substrate to improve wettability or adhesion. Also, instead of corona discharge treatment, plasma discharge treatment can be used instead.

[0013]

(Example) A primer (PC-7A, manufactured by Shin-Etsu Chemical Co., Ltd.) was applied to a bent road mirror (base is acrylic) before processing a reflective film by a spray method, and the temperature was 80 ° C. At 1
After drying for an hour, the substrate surface was covered with a primer-resin layer. Next, a silicone-based hard coat (KP-85 manufactured by Shin-Etsu Chemical Co., Ltd.) was applied by a spray method and dried at 80 ° C. for 2 hours. Further, the surface of the hard coat was treated with a corona treatment device (manufactured by Kasuga Electric) using a wire electrode, the gap length between the electrode tip and the sample surface was 2 mm, the voltage was 26 kV,
Corona treatment was performed three times at a frequency of 39 kHz and a sample feed speed of 4.2 m / min. Then, a photocatalyst solution comprising a hydrolyzed polycondensate of an anatase type titanium oxide sol and an alkyl silicate was applied to the hard coat surface subjected to the corona treatment with isopropyl alcohol at a solid concentration of 0.3 wt%.
, And the photocatalyst solution was applied by a spray method, and dried at 80 ° C. for 1 hour. Finally, a reflective film was formed on the back surface on which the photocatalyst layer was formed by aluminum evaporation. (Comparative Example) A photocatalytic layer was formed in the same manner as in Example except that a road mirror after processing the reflective film was used. About the obtained sample, hydrophilicity by light excitation was evaluated. In addition,
The hydrophilicity due to photoexcitation was examined by the change in the contact angle with water before and after irradiation with a BLB fluorescent lamp having an ultraviolet intensity of 0.5 mW / cm ² for 24 hours. Here, the contact angle with water was measured 30 seconds after a water droplet was dropped on the sample surface from the micro syringe using a contact angle measuring device (CA-150, manufactured by Kyowa Interface Chemical Co., Ltd.). Table 1 shows the results. In the examples, good appearance was obtained without scratches or scorching. In addition, a road mirror showing high hydrophilicity was obtained. On the other hand, in the comparative example, although a high degree of hydrophilicity was obtained, the reflective film was scorched and did not have an appearance usable as a road mirror.

[0014]

[Table 1]

[0015]

According to the present invention, the following effects are exhibited by the above configuration. In a resin mirror having a photocatalyst layer on the surface of a base material, by forming the photocatalyst layer before processing the reflective film, no spark is generated on the reflective film during corona discharge treatment, no scratches and no scorching, and a good appearance is obtained. Obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a surface structure diagram of a member of the present invention.

Claims (5)

[Claims] A first step of forming a hard coat layer; a second step of performing a corona treatment on the hard coat layer; a third step of forming a photocatalytic layer; A fourth step of forming a film, and a method of manufacturing a resin mirror comprising: 2. A first step of forming a hard coat layer, a second step of performing a corona treatment on the hard coat layer, a third step of forming a photocatalyst layer, and a fourth step of performing a bending process. And a fifth step of forming a reflective film. 3. A first step of forming a hard coat layer, a second step of performing a corona treatment on the hard coat layer, a third step of forming a photocatalytic layer, and a fourth step of forming a reflective film. And a fifth step of performing a bending process. A method for manufacturing a resin mirror, comprising: 4. A first step of performing a bending process, a second step of forming a hard coat layer, a third step of performing a corona treatment on the hard coat layer, and a fourth step of forming a photocatalyst layer. And a fifth step of forming a reflective film. 5. A resin mirror manufactured by the manufacturing method according to claim 1.