JPH0256295B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a light diffusing safety glass, more particularly:
It relates to light-diffusing safety glass that allows light to pass through but does not allow people or objects or light sources behind it to be seen. Traditionally, various types of light sources have been used for daylight windows, bathroom doors, balcony wainscoting for condominiums, surface light source panels for ceilings in underground malls, stores, etc.
None of them are completely satisfactory. for example,
When using surigasura or molded glass, there is a drawback that it is easily damaged in the event of an earthquake or when a person or object collides with it, and sharp-angled pieces may scatter or fall, creating a danger. Milky white acrylic boards are also used, but they emit toxic gas in the event of a fire, crack or discolor when used outdoors, have poor weather resistance, warp over time, and are easily stained, making them less durable. There are disadvantages such as inferiority. Furthermore, some plate glasses are made by baking low-melting point glass into opalescent enamel, but like the plate glass and molded glass, this also has the drawback of low safety against breakage. Similarly, there are sheets of glass coated with epoxy-based or melamine-based organic opalescent paints, but the safety against breakage is low, and the hardness of the coating film is low, resulting in scratches on the surface and peeling of the coating film. There are drawbacks in terms of durability. In order to eliminate these drawbacks, as shown in FIG.
There is also one that is tightly sandwiched between two glass plates 3, 3 via 2. This has the advantage of not being easily damaged and having no problems with durability such as warping or peeling, but on the other hand, it does not have sufficient light transmittance, with a total transmittance of about 30% in the visible region. It has only light transparency. On the other hand, if the amount of titanium oxide is reduced in order to improve the light transmittance, there are drawbacks such as objects or people behind it being seen through. Moreover,
Since the transparent adhesive layers 2, 2 for closely sandwiching the intermediate opalescent film 1 between the two glass plates 3, 3 are required, there is also the problem that the number of manufacturing steps is large. In view of the above-mentioned current situation, the present inventor has developed a lighting window,
We conducted extensive research to develop materials suitable for purposes such as bathroom doors, balcony wainscoting, and panels for surface light sources.
As a result, a laminated light-diffusing safety glass consisting of at least two sheets of glass adhered to each other by an adhesive layer made of a specific transparent thermoplastic resin and a specific translucent opacifying agent uniformly dispersed therein has been developed. The present invention was completed based on the discovery that all of the drawbacks of the invention can be overcome. The light-diffusing safety glass of the present invention has high strength,
It exhibits high resistance to damage due to vibrations or collisions with objects or human bodies, and even if it is damaged, fragments will not scatter, and it is highly safe as it is difficult for colliding objects to penetrate. In addition, even when used outdoors for a long time,
There are no problems in terms of weather resistance and durability, and even in the unlikely event of a fire, it is difficult to burn and there is little risk of generating toxic gas. Furthermore, despite its high translucency, it has an extremely unique property in that it can no longer be seen through a person, object, or light source behind it if it is about 15 cm away, for example. The invention will now be described with reference to the accompanying drawings. The light-diffusing safety glass of the present invention, as shown in FIG.
The basic components are two glass plates 10, 10 and an adhesive layer 20 in which a specific translucent opacifier is uniformly dispersed. As the plate glass 10, various types of glass such as ordinary plate glass, polished plate glass, patterned glass, wire mesh or lined plate glass, and colored plate glass can be used. The glass plate 10 may have a slight unevenness on one side, and the two glass plates may be of the same type or different types. There is no particular limit to the thickness of the plate glass 10, and any commercially available glass plate with a thickness of about 2 to 12 mm is suitable for many uses. Of course, depending on the purpose of use, a glass plate with a larger thickness may be used, or one of the two glass plates may have a different thickness. Furthermore, when plate glass with wire mesh or wires is used, the fire prevention properties, flame retardance, flame penetration resistance, etc. of the diffused safety glass of the present invention are further improved, and it has the performance as a Class B fire door as defined in the Fire Service Act. . As the thermoplastic resin used for the adhesive layer 20,
In addition to having an adhesive function for synthetic glass, it is also required to have high weather resistance and to uniformly disperse a translucent opacifying agent, which will be described later. Such thermoplastic resins include α-olefin-vinyl ester copolymers and modified products thereof, ethylene-acrylic acid copolymers, modified ethylene copolymers, acrylic resins,
Examples include modified products of block copolymer rubber, polyurethane resin, vinyl chloride resin, vinyl chloride-vinyl acetate copolymer, ionomer resin, chlorinated polyethylene, chlorinated polypropylene, polyamide resin, polyester resin, and polyvinyl acetate resin. Among these resins, α-olefin-
Vinyl ester copolymers and modified products thereof are preferred. In the α-olefin-vinyl ester copolymer, ethylene, propylene, 1-butene, 1-pentene, etc. can be used as the α-olefin, and ethylene is particularly preferred. Examples of the vinyl ester include vinyl formate, vinyl acetate, vinyl propionate, vinyl butyrate, and vinyl benzoate, with vinyl acetate being particularly preferred. The vinyl ester content in the copolymer is preferably about 5 to 50% by weight. In addition, as a modified product of the α-olefin-vinyl ester copolymer, the copolymer may be saponified with a saponification rate (hydrolysis rate) of 5 to 95%, preferably
A saponified product obtained by saponification to a concentration of 40 to 70%, or a carboxy group-containing unsaturated compound represented by acrylic acid, methacrylic acid, maleic acid, etc., or anhydrous maleic acid, succinic anhydride. Examples include carboxyl-modified products obtained by reacting an acid, a cyclic acid anhydride represented by phthalic anhydride, etc. in a proportion of about 0.1 to 15% by weight with respect to the copolymer. Among these α-olefin-vinyl ester copolymers and their modified products, melt index (190℃, load 2160g
(measured by ) is preferably about 0.5 to 500 g/10 minutes. Furthermore, in the present invention, phenyl salicylate, resorcinol monobenzoate, 2-(2'-hydroxy-3'-t-butyl-
UV absorbers such as 5'-methylphenyl)-5-chlorobenzotriazole, 2,6
-di-t-butyl-P-cresol, tetrakis[methylene-3-(3,5-di-t-butyl-4-
Antioxidants such as hydroxyphenyl propionate] methane and the like may be added. The translucent opacifier that should be uniformly dispersed in the thermoplastic resin is defined as transparent opacifier in the Inorganic Chemistry Handbook (edited by the Inorganic Chemistry Handbook Editorial Committee, published August 15, 1966, page 1080). Among them, those used in the present invention are particularly required to be in the form of fine powders or microcrystals. Such opacifiers include calcium carbonate, alumina, kaolin clay, calcium silicate, magnesium oxide, magnesium hydroxide, aluminum hydroxide, magnesium carbonate, talc,
Feldspar powder, mica, barite, barium carbonate, etc. can be used, and among these, calcium carbonate is particularly preferred. In the present invention, the total light transmittance of the light diffusing safety glass is set to be at least about 35%, but the straight transmittance is kept low so that it becomes impossible to see through when the object, person, or light source behind is about 15 cm away. It is necessary to appropriately select the particle size and blending amount of the opacifying agent. Although it depends on the place where the light-diffusing safety glass of the present invention is used, the purpose of use, the type of light source, the intensity, etc., the above-mentioned opacifying agent generally has an average particle diameter of about 0.1 to 50 μm, preferably
Good results can usually be obtained if the thickness is about 0.5 to 30 μm and the blending amount to the thermoplastic resin is 0.1 to 30% by weight, preferably 1 to 20% by weight.
In particular, when calcium carbonate is used as an opacifying agent, it is preferable that the average particle size of the calcium carbonate be 0.5 to 5 .mu.m, and that the amount of calcium carbonate added to the resin be about 2 to 10% by weight. The thickness of the adhesive layer 20 may also vary depending on the place where the light-diffusing safety glass of the present invention is used, the purpose of use, the amount of the opacifying agent added, etc., but it is usually about 0.3 to 1.0 mm, preferably about 0.38 to 0.7 mm. . In order to manufacture the light-diffusing safety glass of the present invention, the two glass plates 10, 10 and the adhesive layer 20 are
As shown in FIG. 2, they are stacked one on top of the other, degassed so that no air bubbles remain between the layers, and then heated and pressed to the melting temperature of the adhesive layer 20 to make the whole tightly integrated. The light-diffusing safety glass of the present invention is excellent in unique light transmittance (or dispersion), resistance to breakage, fire prevention or flame retardancy, weather resistance, durability, etc., and is suitable for lighting windows, bathroom doors, etc. It can be advantageously used for balcony wainscoting, surface light source panels, etc. both indoors and outdoors. It also has the advantage that it can be easily manufactured with a small number of steps. In addition, in the present invention, it is of course possible to use an appropriate number of three or more plate glasses 10 as required, and to provide a multilayer laminated safety glass structure in which an adhesive layer 20 is arranged between each plate glass. Example 1 Carboxyl modified product of saponified ethylene-vinyl acetate copolymer (melt index 20g/10
Minutes, product name, "Dyumiran Powder C-1550U"
Calcium carbonate microcrystals with an average particle size of approximately 1 μm are uniformly dispersed in a film (manufactured by Takeda Pharmaceutical Co., Ltd.) at a concentration of 3% by weight, and this is formed into a film with a thickness of 0.36 mm. The film was placed between two sheets of ordinary glass (1829) with a thickness of 3 mm.
mm x 914 mm), remove air bubbles between the layers, and then
The glass was heated to 120°C and the whole was tightly integrated with an adhesive pressure of 1 atm to obtain the light-diffusing safety glass of the present invention. When measured in accordance with JIS K6714, although this light-diffusing safety glass has a high total light transmittance of 60%, it is not possible to see through a bright object placed 15 cm behind it, and the object simply exists. That was enough to make it clear. The haze value of this product was 90%. In addition, regarding the above-mentioned light-diffusing glass, JIS R3205
It passed the impact resistance test and heat resistance test of laminated glass sheets according to JIS R3212, as well as the light resistance test of laminated glass sheets for automobiles according to JIS R3212. Example 2 A light-diffusing safety glass of the present invention was obtained in the same manner as in Example 1, except that the amount of calcium carbonate microcrystals was 5% by weight. The total light transmittance of this diffused safety glass is 45%, but the fluorescent light source installed 15 cm behind it is not recognized as a single light source, and the entire diffused safety glass is used as a surface light source. It emitted light. The haze value of this product was 93%. In addition, as in Example 1, JIS R3205 and JIS
I passed the test based on R3212. Example 3 A light-diffusing safety glass of the present invention was obtained in the same manner as in Example 1, except that one of the glass plates was replaced with a wired glass plate with a thickness of 6.7 mm. The light transmittance was the same as in Example 1, and the safety test was also passed. Furthermore, it passed the JIS A-1311 heating test as a Class B fire door for outdoor use. Example 4 Light-diffusing safety glass of the present invention was obtained as in Example 1 except that a translucent opacifier having a particle size shown in Table 1 below was used in the amount shown in Table 1 below. The total light transmittance and haze value of the obtained light-diffusing safety glass were as shown in Table 1.

[Table] Also, a bright object placed 15 cm behind these safety glasses could not be seen through, and the presence of the object could only be seen. Furthermore, the light-diffusing safety glass obtained above was subjected to an impact resistance test and a heat resistance test according to JIS R3205, and a light resistance test for laminated glass sheets for automobiles according to JIS R3212, and it passed both tests. .

[Brief explanation of drawings]

FIG. 1 shows a cross-sectional view of a conventional opalescent safety glass. FIG. 2 is a cross-sectional view of the light-diffusing safety glass of the present invention. 1... Milky white film, 2... Transparent adhesive layer, 3...
... Plate glass, 10 ... Plate glass, 20 ... Adhesive layer in which opacifying agent is uniformly dispersed.

Claims (1)

[Claims] 1. A laminated light-diffusing safety glass made of at least two sheets of glass that are adhered to each other by an adhesive layer made of a thermoplastic resin and a translucent opacifier dispersed therein.