JPS6113043B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a novel high frequency processable retroreflective sheet.

Conventionally, retroreflective sheets have been applied to road signs, license plates, sticker cars, etc., but all of these are flat. Conventional retroreflective sheets do not have high-frequency processability, that is, high-frequency fusing and weldability, so it is almost impossible to create three-dimensional decorative objects, such as accessories, using retroreflective sheets as outer skins. Ta. Therefore, in order to produce decorations using conventional retroreflective sheets, printing is applied to the surface of the retroreflective sheet to enhance the decorative effect, but the decorative effect of such colors is only two-dimensional. It is monotonous and lacks variety, making it unsatisfactory as a decorative object such as an accessory.

However, the present inventors have discovered a new retroreflective sheet that has high-frequency processability that conventional retroreflective sheets do not have, and when this is used as an outer cover and is high-frequency cut and welded to a decorative base material, it has an excellent accessory effect. The inventors discovered a new fact that it is possible to obtain a decorative body with a three-dimensional shape, and completed the present invention.

That is, in the present invention, a resin solution is applied onto a base film to form a resin layer, and while the resin layer is still soft, glass microspheres are sprinkled over the entire surface of the base film to expose a portion of the glass microspheres due to their own weight. The resin solution is applied thinly onto the resin layer where the glass microspheres are exposed so that the exposed parts of the glass microspheres are not buried, and the parts corresponding to the exposed parts of the glass microspheres are covered. A focusing resin layer forming a hemisphere covering the exposed portion is formed, and a metal is vapor-deposited on the focusing resin layer, so that a portion of the focusing resin layer corresponding to the hemisphere forms a hemispherical mirror surface covering the hemisphere. Then, a second adhesive layer is formed on the metal vapor deposited layer, a second soft vinyl chloride film is laminated thereon, and the base film is peeled off from the thus obtained laminate. The present invention relates to a method for manufacturing a high-frequency processable retroreflective sheet, which comprises forming a first adhesive layer on the exposed resin layer and laminating a first soft vinyl chloride film thereon.

Next, the high frequency processable retroreflective sheet of the present invention will be explained with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing a preferred embodiment of a retroreflective sheet obtained by the method of the present invention. In Figure 1, 1 is the first
2 is a first adhesive layer, 3 is a resin layer, 4 is a glass microsphere, 5 is a focal resin layer, 6 is a metal vapor deposited layer, 7 is a second adhesive layer, 8 is a second adhesive layer. 2 soft vinyl chloride film. This retroreflective sheet exhibits retroreflection when viewed from the first soft vinyl chloride film 1 side.

The first soft vinyl chloride film 1 and the second soft vinyl chloride film 8 are high frequency melt cut,
A material that is easy to weld and has a soft surface is preferred. From this point of view, polyvinyl chloride
20 parts of plasticizer per 100 parts (by weight, same below)
Soft products obtained from externally plasticized polyvinyl chloride containing up to 60 parts and internally plasticized polyvinyl chloride such as vinyl chloride and vinyl acetate copolymers prepared by copolymerizing 100 parts of vinyl chloride and 20 to 60 parts of vinyl acetate. Vinyl chloride film is particularly preferably used. The thickness of the soft vinyl chloride film is not particularly limited, but it is usually preferably used that has a thickness of about 50 to 800 microns.

Desired printing or embossing may be applied to the front or back surface of the first soft vinyl chloride film 1, thereby further enhancing the decorative effect.

As the adhesive for forming the first adhesive layer 2 and the second adhesive layer 7, it is preferable to use an adhesive having good fusing properties during high frequency processing. Examples of such adhesives include polyamide adhesives, polyvinyl chloride adhesives, polyacrylic acid ester adhesives, and urethane resin adhesives. The adhesive layer is usually provided to a thickness of about 2 to 5 microns.

The main purpose of the resin layer 3 is to hold and fix the glass microspheres 4, and the glass microspheres 4 must not move due to heat applied during high frequency processing. From this point of view, it is preferable to use a thermosetting resin. Examples of thermosetting resins used include alkyd resins, urea resins, melamine resins,
Examples include urethane resins, epoxy resins, thermosetting acrylic resins, and these may be used alone or in combination. Further, a thermoplastic resin may be appropriately blended with the thermosetting resin within a range that does not impair the above purpose. The thickness of the resin layer 3 is 4 glass microspheres.
It is determined by how much is exposed from the resin layer 3. In order to obtain excellent retroreflectivity, the glass microspheres 4 should be about 1/3 to 2/3, especially 1/3
It is preferable that the resin layer 3 be exposed to a thickness of about 1/3 to 2/3 of the diameter of the glass microspheres 4, and particularly preferably about 1/2 of the diameter of the glass microspheres 4. The resin layer 3 may be colored with a dye or a transparent organic pigment, and in such a case, the metal vapor deposited layer 6
It is possible to obtain retroreflected light of various colors, not limited to metallic luster.

As the glass microspheres 4, those having a refractive index in the range of 1.9 to 2.4 are preferably used for the purpose of obtaining excellent retroreflectivity. If the glass microspheres 4 are too small, it is difficult to form a focal resin layer with the same thickness along the spherical surface, and if they are too large, it is necessary to make the focal resin layer thicker, so it is necessary to form the focal resin layer with the same thickness along the spherical surface. In either case, it is difficult to obtain wide-angle retroreflectivity. From this point of view, the size of the glass microspheres 4 is usually the average sphere diameter.
It can be selected from a range of about 30 to 100μ. In order to obtain uniform retroreflection, it is preferable that the glass microspheres 4 be arranged as densely as possible, but they may be arranged roughly as appropriate if uneven retroreflection is not to be obtained.

The focusing resin layer 5 is formed so that a portion corresponding to the exposed portion of the glass microsphere constitutes a hemisphere covering the exposed portion. Here, the term "hemisphere" includes not only a complete hemisphere, but also a range of about 1/3 to 2/3 of a sphere. By configuring the focusing resin layer 5 in this manner, the portion of the next metal vapor deposited layer 6 corresponding to the glass microspheres forms a hemispherical mirror surface. With this configuration, it is possible to focus not only the incident rays perpendicular to the retroreflective sheet but also the incident rays from any angle,
This provides excellent wide-angle retroreflectivity. The suitable thickness of the focusing resin layer 5 depends on the refractive index and diameter of the glass microspheres 4 and the refractive index of the resin surrounding the glass microspheres, but is usually selected from a range of 5 to 70 microns.

As the resin constituting the focal resin layer 5, the resin layer 3
Similar resins are used to achieve similar purposes and may be similarly colored. Note that resin layer 3
In addition, when a resin mainly composed of thermosetting resin is used for the focal resin layer 5, cracks are likely to occur in the metal vapor deposited layer 6 around the glass microspheres 4 that are in contact with the fused part during high-frequency fusing, just before cutting. Despite the presence of the metal vapor deposited layer 6, no sparks are generated and the advantage is that high frequency workability is good.

The metal vapor deposited layer 6 is formed so that a portion corresponding to the hemispherical portion of the focusing resin layer 5 constitutes a hemispherical mirror surface covering the hemispherical portion. Metal vapor deposition layer 6
There are no particular restrictions on the metals that make up the
Examples include nickel alloy. Usually aluminum is particularly preferably used. The thickness of the metal vapor deposited layer is preferably about 0.05 to 0.1 μm.

If the thickness is less than 0.05μ, the reflectivity will be poor and it will be difficult to obtain excellent retroreflectivity, and if it is thicker than 0.1μ, the reflectivity will not improve, so anything thicker than 0.1μ is economically disadvantageous. It is.

The high-frequency processable retroreflective sheet obtained by the method of the present invention has both sides covered with a soft vinyl chloride film that is easy to high-frequency cut and weld. Since the end face is covered with vinyl film, the end face is beautifully finished, and since each layer is not exposed on the end face, there is no risk of each layer peeling off from the fused part, and it is also suitable for decoration when adhesively processed to a decorative base material. Since there is a soft vinyl chloride film on the base material side, high frequency welding can be easily performed. In addition, since the surface is coated with a soft vinyl chloride film, it maintains its retroreflective ability with excellent robustness for a long period of time, and has an excellent feel when used in applications such as accessories. Furthermore, the high-frequency processable retroreflective sheet obtained by the method of the present invention has the above-mentioned structure, so it is a highly flexible retroreflective sheet, and has the above-mentioned specific retroreflective structure, so it is an excellent retroreflective sheet. It exhibits reflective ability.

As a method for manufacturing the high frequency processable retroreflective sheet of the present invention, the method shown in FIG. 2 is employed, taking into account the use of a soft vinyl chloride film, which has poor thermal dimensional stability.

In FIG. 2, 9 is a base film.
For example, the base film has a thickness of 25 to 75μ.
A polyester film of about 100% is preferably used. A resin solution is applied onto the base film 9 to form the resin layer 3. Later base film 9
is peeled off from the resin layer 3, but if the peelability is poor, a coating layer of a resin with poor adhesion, such as polyvinyl chloride or cellulose acetate, is provided on the base film 9 in advance, and the resin layer 3 is coated on top of that. may be formed. Glass microspheres 4 are sprinkled over the entire surface of the resin layer 3 while it is still soft. The glass microspheres 4 sink into the resin layer 3 due to their own weight. The degree of exposure of the glass microspheres 4 from the resin layer 3 can be adjusted by appropriately selecting the thickness of the resin layer 3 and the diameter of the glass microspheres 4. The glass microspheres 4 are then fixed to the resin layer 3 by heating and drying the resin layer 3. A resin solution is applied onto the resin layer 3 where the glass microspheres 4 are exposed and dried to form a focal resin layer 5. Although the thickness of the focal resin layer 5 is adjusted by adjusting the amount of resin solution applied, it is necessary to prevent at least the exposed portions of the glass microspheres 4 from being buried. If the glass microspheres 4 are completely buried, the metal vapor deposited layer provided next becomes flat and cannot form a hemispherical mirror surface, making it impossible to obtain excellent retroreflectivity. In this way, a focusing resin layer 5 is obtained in which the portion corresponding to the exposed portion of the glass microsphere 4 constitutes a hemisphere covering the exposed portion. Next, a metal is deposited on the focal resin layer 5 to form a metal deposited layer 6. A portion of the metal vapor deposited layer 6 corresponding to the hemispherical portion of the focal resin layer 5 constitutes a hemispherical mirror surface. Metal evaporation can be done using the usual vacuum evaporation method, sputtering method,
This is done by ion plating method etc. Apply adhesive on the metal vapor deposited layer 6 and apply the second layer.
An adhesive layer 7 is formed, and a second soft vinyl chloride resin film 8 is laminated thereon. By peeling the base film 9 from the laminate thus obtained, forming the first adhesive layer 2 on the exposed resin layer 3, and then laminating the first soft vinyl chloride film 1 thereon. A high frequency processable retroreflective sheet of the present invention is obtained.

The high-frequency processable retroreflective sheet obtained by the method of the present invention may be used for flat applications such as road signs, license plates, stickers, etc. by taking advantage of its excellent retroreflectivity. Taking advantage of its excellent feel, it is particularly preferable to use it as a three-dimensional retroreflective decorative body as an outer skin. FIG. 3 is a schematic cross-sectional view showing one embodiment of such a decorative body. In FIG. 3, 10 is a high-frequency processable retroreflective sheet of the present invention, 11 is a resin foam, and 12 is a decorative base material.
As the resin foam 11, any material can be used as long as it can be cut by high frequency, welded, and easily compressed, and examples thereof include polyurethane foam, polyvinyl chloride foam, and the like. Decorative base material 1
As the material 2, for example, textiles, leather, velvet, felt, resin sheets, etc. can be used as appropriate depending on the purpose.

To produce such a decorative body, the resin foam 11 is layered on the decorative base material 12, and the retroreflective sheet 10 is further layered on top of the resin foam 11 so that the second soft vinyl chloride film 8 is on the side of the resin foam 11. ,
This may be molded using a normal high frequency welder. For example, a mold having an inner shape corresponding to the outer shape of the retroreflective sheet 10 shown in FIG. The resin foam 11 is melt-cut and welded to obtain a three-dimensional decorative body having the retroreflective sheet 10 as an outer skin, as shown in FIG. The decorative bodies thus obtained can be used as accessories, such as hats,
It is used by hanging or sewing on clothes, bags, etc. In this case, it is not only used as an accessory, but also helps prevent traffic accidents at night. Note that the decoration may be applied to the back surface of the decorative base material 12 with a pressure-sensitive or heat-sensitive adhesive, and if necessary, a release paper may be layered on top of the adhesive so that it can be pasted at any required location. .

Next, the present invention will be explained with reference to Examples.

Example 1 After forming a coating layer of cellulose acetate with a thickness of 0.5μ on a polyethylene terephthalate film with a thickness of 25μ, 3 parts of butylated melamine resin and 1 part of castor oil modified alkyd resin were mixed in a toluene-butyl alcohol mixed solvent (3 parts). :2 volume ratio) was applied so that the thickness after drying was 8 μm. After leaving it for a while to volatilize the solvent, glass microspheres with an average sphere diameter of 50 μm and a refractive index of 2.3 were sprinkled over the entire surface. The glass microsphere sank by about half its diameter due to its own weight. The resin layer was then dried and solidified by heating. Apply the same resin solution as above on the exposed resin layer of the glass microspheres so that the thickness after drying is 10μ.
It was dried to form a focal resin layer. Aluminum was deposited on the focal resin layer by a vacuum deposition method to a thickness of 0.05 μm to form an aluminum deposited layer. On top of that, a urethane resin adhesive is applied to form an adhesive layer with a thickness of 3μ, and on top of that, a soft vinyl chloride film with a thickness of 200μ (40 parts of dioctyl phthalate per 100 parts of polyvinyl chloride) is applied.
(formed from a mixture of two parts) were laminated together. The polyethylene terephthalate film was peeled off from the thus obtained laminate, and an adhesive layer with a thickness of 3 μm was formed on the exposed resin layer using the same adhesive as above,
The same soft vinyl chloride film as above was laminated thereon.

The high-frequency processable retroreflective sheet thus obtained exhibited excellent retroreflectivity and had a soft surface feel.

Example 2 Vinyl chloride as a soft vinyl chloride film
A high-frequency processable retroreflective sheet was obtained in the same manner as in Example 1, except that a vinyl chloride-vinyl acetate copolymer obtained by copolymerizing 100 parts of vinyl acetate and 50 parts of vinyl acetate was used.

The obtained sheet showed excellent retroreflectivity,
Moreover, the surface was soft to the touch.

Application example: Lay a sheet of polyurethane foam on top of the felt, and then layer the high-frequency processable retroreflective sheet obtained in Example 1 on top of it, and then layer the high-frequency processable retroreflective sheet 1 shown in FIG. 3 on top of that.
The molds having an inner shape corresponding to the outer shape of 0 were placed one on top of the other, and a high frequency voltage of 2 kW and 5×10 ⁷ hertz was applied while pressurizing. The high-frequency processable retroreflective sheet and the polyurethane foam were thus cut and welded to obtain a decorative body having the three-dimensional shape shown in FIG. The resulting decorative body was suitable as an accessory due to its three-dimensional shape and decorative effect.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view showing a preferred embodiment of a high-frequency processable retroreflective sheet obtained by the method of the present invention, and FIG. 2 is a schematic cross-sectional view showing one embodiment of a laminate obtained in the middle of the process of the method of the present invention. 3 are schematic cross-sectional views showing one embodiment of a decorative body produced using a high-frequency processable retroreflective sheet obtained by the method of the present invention. (Symbols in drawings) 1: first soft vinyl chloride film, 2: first adhesive layer, 3: resin layer, 4: glass microspheres, 5: focal resin layer, 6: metal vapor deposited layer,
7: Second adhesive layer, 8: Second soft vinyl chloride film, 9: Base film, 10: High frequency processable retroreflective sheet, 11: Resin foam, 12:
Decorative base material.

Claims (1)

[Claims] 1. Apply a resin solution on the base film to form a resin layer, and while the resin layer is still soft, sprinkle glass microspheres over the entire surface so that the glass microspheres partially expose the resin due to their own weight. A resin solution is applied thinly onto the resin layer where the glass microspheres are exposed so as not to bury the exposed parts of the glass microspheres, so that the parts corresponding to the exposed parts of the glass microspheres cover the exposed parts. forming a focal resin layer constituting a hemisphere,
A metal is deposited on the focal resin layer to form a metal deposited layer whose portion corresponding to the hemispherical portion of the focal resin layer constitutes a hemispherical mirror surface covering the hemispherical portion. forming a second adhesive layer, laminating a second soft vinyl chloride film thereon, peeling the base film from the thus obtained laminate, and then forming a first adhesive layer on the exposed resin layer; A method for manufacturing a high-frequency processable retroreflective sheet, which comprises laminating a first soft vinyl chloride film thereon.