JP2001262522A - Self purifying retroreflection body and method manufacturing therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the reflection performance of a retroreflection body having a self purifying function and provide a simple method of manufacturing the reflection body. SOLUTION: A self purifying sheet 2 is applied onto the surface of a prism reflector A, and the outermost layer thereof forms a photocatalyst layer 24. The surface is made hydrophilic by the activation of the photocatalyst 24, pollutants are removed, and the self purification can be maintained for long period. In addition, because a protective film 3 is applied separably onto the surface of the photocatalyst layer 24, a rubbing and an adhesion of contamination in molding is prevented and a damage and pollution in transportation and installation on a road can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a self-cleaning retroreflector which is suitably used as a gaze guide or a road stud installed on a side edge of a road or a median strip for the purpose of guiding a gaze of a vehicle, and its manufacture. It's about the method.

[0002]

2. Description of the Related Art A retroreflective prism is used for a gaze guide or the like installed on a road for the purpose of guiding the gaze of a vehicle. It is contaminated, and its gaze guidance function is significantly reduced within a few months after installation. In view of this, the present inventors have previously proposed in Japanese Patent Application No. 10-197454 a retroreflector having an antifouling function using a photocatalyst and a method of manufacturing the same. This is a method in which a photocatalyst such as titanium oxide is layered on a reflector base material so that the base material has a self-cleaning function.

[0003]

However, in the reflector having retroreflective properties and the method of manufacturing the same as proposed above, means for protecting the surface of the photocatalyst layer at the time of injection molding is not provided at all. As a result, the outer surface of the photocatalyst layer was in direct contact with the wall surface of the molding die, and stable performance was not obtained due to friction and adhesion of dirt.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to improve the above-mentioned drawbacks, and has the following structure. That is, the self-cleaning retroreflector according to the present invention has a self-cleaning sheet coated on the surface of the prism reflector whose rear surface is prism processed so that incident light from the front surface is retroreflected from the prism toward the light source. The self-cleaning sheet is composed of a sheet substrate, a silicon coat layer and a photocatalyst layer are sequentially deposited on the surface thereof, and a protective film is further adhered to the surface of the photocatalytic layer, and the protective film adheres to the substrate. An adhesive layer is applied to a surface of the protective film, which is in contact with the photocatalyst layer, and the protective film is detachable.

[0005] The invention is characterized in that the silicon coat layer is formed by polymerizing a hydrolyzate of alkoxysilane or formed by polysilazane or a modified product thereof.

Further, the photocatalyst layer may be made of a mixed composition of a hydrolyzate of alkoxysilane and titania sol or a mixed composition of a hydrolyzate of alkoxylane, titania sol and amorphous titanium peroxide sol. It is characterized by being formed.

Further, the adhesive layer is formed of an adhesive mainly composed of EVA or an adhesive mainly composed of an acrylic resin.

On the other hand, in the method of manufacturing a self-cleaning retroreflector according to the present invention, a silicon coat layer is formed on a sheet substrate in the mold of an injection molding machine to which a prism reflector molding mold is attached. At the same time, a self-cleaning sheet having a photocatalytic layer formed on its outer surface and a protective film having an adhesive layer formed thereon are sequentially mounted, and a molten synthetic resin is supplied into the mold and injection-molded, whereby the back surface is prism-processed. At the same time as molding a prism reflector so that incident light from the surface is retroreflected from the prism in the light source direction,
A self-cleaning sheet and a protective film are applied to the surface.

[0009]

Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 is a sectional view showing an embodiment of a self-cleaning retroreflective body according to the present invention, and FIG.
(A) and (B) are cross-sectional views showing a main part of the method for manufacturing a self-cleaning retroreflector according to the present invention, and FIG. 3 shows the self-cleaning retroreflector according to the present invention applied to a road gaze guide. FIG. 4 is a cross-sectional view taken along a line a-a in FIG. 3.

First, in FIG. 1, A denotes a self-cleaning retroreflector according to the present invention, which comprises a prism reflector 1, a self-cleaning sheet 2, and a protective film 3. The prism reflector 1 is formed of a translucent synthetic resin such as polycarbonate, acrylic resin, polyvinyl chloride, or the like, and has a prism 11 processed on the back surface.
The prism reflector 1 is configured such that light from a headlight or the like incident from the front surface is retroreflected by the prism 11 and returns to the light source direction.

The self-cleaning sheet 2 includes a sheet substrate 21, a primer layer 22, a silicon coat layer 23, and a photocatalyst layer 24.
The sheet substrate 21 is formed of a plastic sheet or glass of polycarbonate, acrylic resin, polytetraterephthalate, polyolefin, a modified derivative thereof, or the like, and has a thickness of 0.1 to 2. Those having a thickness of about 0 mm are preferably used.

The primer layer 22 is for improving the adhesion between the upper silicon coat layer 23 and the sheet substrate 21, and an acrylic silicon-based coating film having adhesion to both of them is preferable.

The silicon coat layer 23 is formed by a method of polymerizing a hydrolyzate of alkoxysilane or a method of forming a siliceous ceramic layer from a coating forming composition comprising polysilazane or a modified product thereof. The silicon coat layer 23 has no primer layer 22 and the sheet base 2
1 may be formed directly.

The photocatalyst layer 24 is a transparent layer containing a photocatalytic semiconductor material. When the photocatalyst layer 24 is irradiated with ultraviolet rays, the photocatalyst is activated and the self-cleaning sheet 2 is formed.
Has a hydrophilic surface, and functions to clean contaminants attached to the surface due to rainfall or the like. Specifically, the photocatalyst layer 24 is a mixed composition of a hydrolyzate of alkoxysilane and titania sol, a mixed composition of titania sol and amorphous titanium peroxide sol, a hydrolyzate of alkoxylan, titania sol and amorphous titanium peroxide sol. And the like.

To form the primer layer 22, the silicon coat layer 23 and the photocatalyst layer 24 on the sheet substrate 21, a coating liquid for forming these is applied by spray coating, dipping coating, flow coating, spin coating, or the like. It can be formed by forming a film.

The protective film 3 comprises a film substrate 31 and an adhesive layer 32. As the film substrate 31, a film such as polyethylene, polypropylene, or polyethylene terephthalate is used. As the adhesive, an EVA resin or an acrylic resin is preferably used as a main component. The protective film 3 is made of 100 of the injection molding machine.
It has high temperature resistance to withstand mold temperature of over ℃. Therefore, the thickness of the film substrate 31 is set to 0.25 mm.
The above soft sheet may be used.

Next, a method of manufacturing the self-cleaning retroreflector A according to the present invention will be described. In the present invention, the self-cleaning sheet 2 and the protective film 3 are simultaneously adhered and integrated at the time of molding the prism reflector 1, so that a molded product having stable performance can be obtained without need for a post-process. Things.

That is, as shown in FIG. 2A, the mold 4 of the injection molding machine includes a front-side molding portion 41 having a smooth inner surface and a rear-side molding portion 42 having an inner surface shape corresponding to the irregularities of the prism 11. The self-cleaning sheet 2 is covered with the adhesive layer 32 of the protective film 3 by mounting the self-cleaning sheet 2 on the adhesive layer 32 of the protective film 3. Attach as if to wear.

On the other hand, in such a state, the synthetic resin temperature of the prism reflector 1 is melted in a temperature range higher than the melting point of the resin and lower than the decomposition temperature, and the temperature of the mold 4 is set to 50 to 50.
The temperature is set to 300 ° C., preferably 50 to 200 ° C., more preferably 50 to 100 ° C., and the molten synthetic resin is supplied into the mold 4 in the direction of arrow B to perform injection molding.

In this way, the prism reflector 1 having the back surface processed by the prism 11 is molded, and simultaneously with the molding, the self-cleaning sheet 2 and the protective film 3 are sequentially formed so that the film substrate 31 becomes the outermost surface. The applied self-cleaning retroreflector A is molded.

FIGS. 3 and 4 show an embodiment of the gaze guide 5 to which the self-cleaning retroreflective member A thus formed is attached, as shown in FIG. And a reflector frame 52 and a self-cleaning retroreflector A, which are installed on the side edges of the road. Self-cleaning retroreflector A
Is usually formed of a metal such as aluminum or iron or a synthetic resin such as polyethylene, ABS resin, FRP, polycarbonate, or AAS resin. On the back surface of the self-cleaning retroreflector A, that is, on the back side of the prism 11, a back plate 54 is hermetically bonded by ultrasonic bonding or the like via an air layer 53 to prevent moisture and dust from entering the air layer 53. are doing.

[0022]

Embodiments of the present invention will be described below.

(Example 1) An acrylic silicone paint was applied as a primer to a polycarbonate sheet (0.5 mm thick) by a flow coating method.
After heating for a minute, a primer layer was formed. A silicon-based coating composed of a silicon hard coating agent was applied on the upper surface by the same flow coating method, and heated at 120 ° C. for 60 minutes to form a silicon coating layer. Next, after increasing the wettability by performing a corona discharge treatment on the silicon coat layer, a coating composition containing titanium dioxide using silicon as a binder is applied by spray coating, and heated at 120 ° C. for 30 minutes to form a photocatalyst. A self-cleaning sheet having a coating film containing titanium dioxide was obtained.

After sticking a protective film (adhesive component: EVA) having an adhesive layer on the back surface to the self-cleaning sheet, the sheet is made into a reflector having a diameter of 100 mm.
Then, the protective film was attached so that the protective film was in contact with the inner surface of the molding part on the front side of the mold. The temperature of the mold was previously raised to 80 ° C, and the polycarbonate for the reflector was heated to 300 ° C and melted. Next, the mold was closed and the molten polycarbonate was injected to obtain a reflector having a photocatalyst layer.

A back plate formed of ABS resin was adhered to the reflector by an ultrasonic method to obtain a visual guide mark having a diameter of 100 mm having a photocatalyst layer. After peeling off the protective film attached to the surface of the reflector, the surface of the photocatalyst layer is self-cleaned by irradiating the surface of the photocatalyst layer with a black light blue (BLB) fluorescent lamp at an ultraviolet intensity of 1.5 mw / cm 2 for 24 hours. When the photocatalyst of the conductive sheet was activated and the contact angle of the surface with water was examined, the contact angle before irradiation with ultraviolet light was 40 degrees, but the contact angle after irradiation was reduced to 2 degrees. Also,
When the observation angle is 0.2 degree and the incident angle is 0 degree, the reflection angle is 109 cd
/10.76 lx.

As described above, the contact angle is increased by 2
When the contact angle was changed to 50 degrees, the change in the contact angle was examined. The contact angle was 3 degrees after 50 hours, 5 degrees after 100 hours, and 7 degrees after 200 hours. The lower the contact angle is, the higher the hydrophilicity is, which is preferable.

Comparative Example 1 A self-cleaning sheet having a coating containing titanium dioxide as a photocatalyst was obtained in the same manner as in Example 1. This sheet was cut to a diameter of 100 mm, which is the size of the reflector, and was mounted so that the photocatalyst layer was in contact with the inner surface of the front side molded portion of the mold. Similarly, the mold was heated to 80 ° C. in advance, and the polycarbonate for the reflector was heated to 300 ° C. and melted. Next, the mold was closed and the molten polycarbonate was injected to obtain a reflector having a photocatalyst layer.

As in the case of the first embodiment, AB
The back plate formed of the S resin was adhered by an ultrasonic method to obtain a visual guide mark having a photocatalyst layer and having a diameter of 100 mm. A photocatalyst of the self-cleaning sheet was activated by irradiating the surface of the reflector with ultraviolet light of 1.5 mw per square cm for 24 hours using a black light blue (BLB) fluorescent lamp,
When the contact angle of the surface to water was examined, the contact angle before irradiation with ultraviolet light was 48 degrees, but the contact angle after irradiation was reduced to 2 degrees. Further, the reflection luminance value at an observation angle of 0.2 degrees and an incident angle of 0 degrees was 109 cd / 10.76 lx.

As described above, the contact angle is increased by 2
When the contact angle was changed to 50 degrees after 50 hours, the contact angle was changed to 6 degrees or 10 degrees.
The value was 9 degrees after 0 hours and 15 degrees after 200 hours, which was inferior to that of Example 1.

Comparative Example 2 Polycarbonate was heated to 300 ° C. and melted in an injection molding machine for molding a reflector, while the mold temperature was set to 80 ° C., and the molten polycarbonate was melted in the mold. A reflector having no photocatalyst layer was molded by injection.

In the same manner as in Embodiment 1, AB
The back plate molded with S resin was adhered by an ultrasonic method to obtain a visual guide. Black light blue (BL
B) Irradiation with 1.5 mw / cm 2 ultraviolet light for 24 hours using a fluorescent lamp, but the contact angle of water on the surface was 83 degrees, which was almost unchanged from the initial stage. In addition, the contact angle before ultraviolet irradiation was 82 degrees. In addition, observation angle 0.2 degrees,
The reflection luminance value at an incident angle of 0 degree is 110 cd / 10.76.
lx. Table 1 summarizes the measurement results of Example 1 and Comparative Examples 1 and 2.

[0032]

[Table 1]

The self-cleaning function of the line-of-sight guide in Example 1 and Comparative Examples 1 and 2 was tested and installed for one month on the company premises along the national highway, and evaluated by the change in the reflected luminance. As shown in Table 2, the results of Examples 1 and Comparative Example 1 had a reflection luminance of 102 cd and 101 cd, respectively, whereas those of Comparative Example 2 (conventional type) showed the adhesion of exhaust gas and the like. And the reflection luminance was halved to 48 cd.

[0034]

[Table 2]

[0035]

As described in detail above, in the present invention, a self-cleaning sheet is adhered to the surface of the prism reflector, and this self-cleaning sheet is made of a sheet base material, and has a silicon coat layer and a photocatalyst on its surface. Since the layers are sequentially deposited, even if contaminants such as exhaust gas adhere to the surface of the reflective surface, the strong oxidizing power of the activated photocatalyst decomposes the contaminants and simultaneously renders the surface hydrophilic. This makes it difficult for water to penetrate between the contaminants adhering to the surface and the surface and cause the contaminants to float, and even if it adheres, it is easily washed away and removed by rainfall, etc. The substance hardly accumulates, and the visibility of the reflection surface can be maintained in a good state for a long time.

Further, in the present invention, since the protective film is applied to the surface of the photocatalyst layer, it prevents friction and dirt from adhering when the product according to the present invention is transported or installed on a road. can do.

Further, in the method for manufacturing a self-cleaning retroreflector according to the present invention, a protective film is mounted on the outer surface of the photocatalyst layer and the prism reflector is molded, and at the same time, the self-cleaning sheet and the protective film are formed on the surface. Therefore, labor and cost for attaching the protective film can be reduced.

Further, as is clear from the comparison between Example 1 in Table 1 and Comparative Example 1, it is understood that Example 1 is superior in terms of hydrophilicity. Further, the contact angle of the first embodiment can be maintained at a low state for a long time even when the contact angle is changed in a state of being left in a dark place (in a state where ultraviolet rays are blocked). This is because, in the manufacturing process of Example 1, by performing injection molding with the protective film adhered to the photocatalyst layer, the photocatalyst layer can be prevented from being directly damaged by friction or adhered to dirt. Probably because there is.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a self-cleaning retroreflector according to the present invention.

FIGS. 2A and 2B are cross-sectional views each showing a main part of a method for manufacturing a self-cleaning retroreflector according to the present invention.

FIG. 3 is a front view showing an embodiment in which the self-cleaning reflector according to the present invention is applied to a road gaze guide.

FIG. 4 is a sectional view taken along a line aa in FIG. 3;

[Explanation of symbols]

 A Self-cleaning retroreflector 1 Prism reflector 11 Prism 2 Self-cleaning sheet 21 Sheet base 22 Primer layer 23 Silicon coat layer 24 Photocatalytic layer 3 Protective film 31 Film base 32 Adhesive layer 4 Mold 41 Front side molding part 42 Back side Side molding 5 Line of sight guide 51 Support 52 Frame for reflector 53 Air layer 54 Back plate

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G09F 13/16 B01D 53/36 JB F Term (Reference) 2D064 AA03 AA11 AA22 BA08 CA02 CA09 DA06 EB25 EB34 HA01 HA14 JA01 2H042 EA04 EA13 EA17 EA19 4D048 AA21 AB03 BA07X BA07Y BB03 CA07 CA08 CC06 CC12 CC38 EA01 4G069 AA03 AA08 BA04A BA04B BA22A BA22B BA48A BC50A BC50B CA01 CA03 CA11 CA13 EA08 CA03 EA05 A03 EB03 EA11 FA02 CB FA07

Claims (9)

[Claims] 1. A self-cleaning sheet is adhered to the surface of a prism reflector whose rear surface is prism processed so that incident light from the front surface is retroreflected by the prism in the direction of the light source. It is composed of a sheet substrate, and a silicon coat layer and a photocatalyst layer are sequentially layered on the surface thereof,
Further, a protective film is applied to the surface of the photocatalyst layer,
This self-cleaning retroreflective body is characterized in that the protective film comprises a film substrate and an adhesive layer, an adhesive layer is applied to a surface in contact with the photocatalyst layer, and the protective film is detachable. 2. The self-cleaning retroreflector according to claim 1, wherein the silicon coat layer is formed by polymerizing a hydrolyzate of alkoxysilane. 3. The self-cleaning retroreflector according to claim 1, wherein the silicon coat layer is formed from polysilazane or a modified product thereof. 4. The self-cleaning retroreflection according to claim 1, wherein the photocatalyst layer is formed of a mixed composition of a hydrolyzate of alkoxysilane and titania sol. body. 5. The self-cleaning retroreflector according to claim 1, wherein the photocatalytic layer is formed of a mixture of a titania sol and an amorphous titania peroxide sol. 6. The photocatalyst layer according to claim 1, wherein the photocatalyst layer is formed by a mixed composition of a hydrolyzate of an alkoxylane, a titania sol and an amorphous titanium peroxide sol. Self-cleaning retroreflector as described. 7. The pressure-sensitive adhesive layer according to claim 1, wherein the pressure-sensitive adhesive layer is formed of a pressure-sensitive adhesive containing EVA as a main component.
7. The self-cleaning retroreflector according to any one of 6. 8. The self-cleaning retroreflective body according to claim 1, wherein the adhesive layer is formed of an adhesive containing an acrylic resin as a main component. 9. A self-cleaning sheet in which a silicon coat layer is formed on a sheet substrate and a photocatalyst layer is formed on the outer surface of the self-cleaning sheet, and an adhesive is provided in a mold of an injection molding machine to which a prism reflector forming mold is attached. The protective film coated with the agent is sequentially mounted, the molten synthetic resin is supplied into the mold, and injection molding is performed, so that the back surface is prism-processed, and the incident light from the front surface is returned to the light source direction from the prism. A method of manufacturing a self-cleaning retroreflector, comprising forming a self-cleaning sheet and a protective film on the surface of a prism reflector that is to be reflected.