JPH0588725B2 - - Google Patents

Description

[Detailed description of the invention]

Industrial Application Fields This invention is a synthetic resin laminated protective film used in, for example, ski goggles, motorcycle windshields, helmet windshields, underwater goggles, gas masks, transparent panels for greenhouses, mirrors, etc. This invention relates to a method for manufacturing a cloud plate. Conventional technology Conventionally, synthetic resin anti-fogging plates are usually made of cellulose-based synthetic resin sheets or films such as acetate plastic, cellulose acetate butyrate, or cellulose propionate, which are treated with alkali. Therefore, materials with anti-fogging properties on the surface are commonly used (for example, JP-A-56-76434, JP-A No. 57-76).
No. 36131). Problems that the invention aims to solve However, since the conventional anti-fogging plates mentioned above are made of cellulose-based synthetic resin, there is an essential problem in that their applications are restricted due to their properties. The point was hot. In other words, it is unsuitable for use in applications that require particularly high strength, heat resistance, impact resistance, etc., and is not necessarily fully satisfactory in relation to the required physical properties in various applications. It wasn't something. In addition, the alkali treatment used in the production of conventional anti-fog plates is generally performed by a dipping method in which the base material is immersed in an aqueous solution such as sodium hydroxide and/or potassium hydroxide. In particular, when manufacturing thick anti-fog plates, not only can it be difficult to perform continuous processing with high efficiency, but also because both sides of the base material are anti-fog treated, depending on the application. In the end, rainwater and snow tend to adhere to the outer surface, which does not require anti-fog properties, and this can obstruct visibility, or even freeze, which can eventually obstruct visibility. was. To solve the above problems, it is possible to create a laminated anti-fog plate by pasting the above-mentioned anti-fog film on one or both sides of a synthetic resin substrate with the required physical properties. Of course it can be considered. However, the anti-fog treated surface of cellulose resin film or sheet has an excess of hydroxyl groups due to alkali treatment, so various types of adhesives, such as those commonly used for bonding resin plates, cannot be used. It was not possible to achieve strong adhesive integration with other synthetic resin sheets by using adhesives, and although the advantages of laminated anti-fogging plates were recognized, their practical application was hindered. That is the reality. Based on the above-mentioned technical background, the inventors conducted various experiments and research with the intention of commercializing a laminated anti-fog plate, and found that it was possible to use a specified adhesive. This led to the discovery that the desired strong adhesive force could be achieved by utilizing the characteristics of the anti-fog treated surface, and this invention was completed. Means for Solving the Problems Therefore, the present invention uses a one-component moisture-curing polyurethane resin adhesive to bond a double-sided anti-fog film or sheet to at least one side of the transparent synthetic resin substrate. It is intended for use. That is, the present invention provides a method for obtaining a laminated anti-fog board by bonding a double-sided anti-fog film or sheet made of cellulose-based synthetic resin that has been subjected to anti-fog treatment on at least one side of a synthetic resin substrate. The gist of this invention is a method for manufacturing a laminated synthetic resin anti-fogging plate, which is characterized by using an adhesive made of a liquid moisture-curable polyurethane resin. As the material for the above-mentioned anti-fog film or sheet, one selected arbitrarily from the group of diacetyl cellulose, triacetyl cellulose, cellulose acetate butyrate, and cellulose propionate is suitably used, as in conventional products. The anti-fog treatment on both sides is done according to the conventional method.
For example, it can be effectively carried out by immersion treatment in an alkaline aqueous solution as shown in Japanese Patent Application Laid-Open Nos. 56-76434 and 57-36131. On the other hand, the synthetic resin substrate to be laminated on one side of the above-mentioned anti-fog film or sheet is a transparent or colored thermoplastic synthetic resin sheet with good optical transparency in general applications where transparency is required. For example, a translucent plate may be used for purposes such as a lighting board, and a substantially opaque plate with a reflective layer on one side may be used for purposes such as a mirror. It is possible that you may be Materials for this substrate include, for example, the same cellulose synthetic resin as the anti-fog film material, vinyl chloride resin, polyester resin, or if heat resistance is required, acrylic resin, styrene resin, or When these copolymer resins require further impact resistance, polycarbonate resins are used. That is, a type of resin that meets the required characteristics is selected from the resin group described above depending on the relationship with each application. In addition, if scratch resistance is required on the surface, acrylic,
A material provided with a transparent surface hardening film such as silicone-based or methylolated melamine-based material may also be used. By the way, the one-component moisture-curing polyurethane resin used as the adhesive between the above-mentioned anti-fog film or sheet and the substrate is mainly composed of -NCO groups at the terminal end, and is a hydrophilic, flexible polyether-based or polyester-based polyurethane resin. It is a liquid urethane resin composition containing a linear or branched polyurethane prepolymer having a chain structure as a main component, and in particular, it needs to be a one-component type. Only by selecting and using this specific adhesive can it be possible to achieve sufficiently strong bonding and integration of the synthetic resin substrate with the double-sided antifogging film or sheet. Although the principle mechanism of adhesion is not yet fully understood by the present inventor, acrylic resin adhesives, vinyl resin adhesives, and epoxy resin adhesives that do not have isocyanate groups are used. When using the above urethane resin composition as an adhesive, considering that good adhesion cannot be achieved with -NCO of the adhesive, etc.
It is thought that a good adhesion effect is obtained because the groups bond with -OH groups present in excess on the surface of the alkali-treated antifogging film. Furthermore, even if the urethane resin composition has an isocyanate group, a two-component one is insufficient for adhesion because the isocyanate group only reacts with the amine or polyol used as a curing agent.
It is considered that sufficient adhesive strength cannot be obtained because the reaction with the -OH groups on the surface of the antifogging film or sheet is insufficient.
Commercially available one-component moisture-curing polyurethane resin adhesives suitable for use in this invention include "Monotak" (manufactured by Daiichi Kogyo Seiyaku) and "MC-
1000” (manufactured by Sakai Chemical Industries), “Sumiji Yule E-21”
(manufactured by Sumitomo Bayer Urethane), "Takenate A-7"
(manufactured by Takeda Pharmaceutical Co., Ltd.), "Polynate 955H" (manufactured by Toyo Polymer), and "Coronate 2014" (manufactured by Nippon Polyurethane Industries). Effects of the Invention As is already clear from the above, the present invention can be obtained as a laminated anti-fog plate in which a synthetic resin substrate is integrally bonded to one side of an anti-fog film or sheet subjected to an anti-fog treatment. Therefore, by selecting a substrate with the required properties, it is possible to create an anti-fog plate of any thickness with desired properties such as excellent mechanical strength, heat resistance, and impact resistance. can be easily manufactured, and the range of applications of the anti-fog plate can be further expanded. Of course, since it is possible to freely provide anti-fog properties on only one side of the plate, it is possible to provide an anti-fog plate that avoids the disadvantage that rainwater, snow, etc. easily adhere to the other side. Therefore, especially for ski goggles and the like that are used in cold environments, we have developed an anti-fog plate that does not have the essential drawbacks of conventional products, such as the tendency for visibility to be obstructed by the freezing of adhering moisture. can be provided. Of course, the provision of such a laminated anti-fog board requires the use of a specific adhesive consisting of a one-component moisture-curing polyurethane resin composition to ensure sufficient strength between the anti-fog film or sheet and the synthetic resin substrate. This was made possible by the realization of integrated adhesive, and by realizing this excellent adhesive effect, it not only increases the durability of the anti-fog plate itself, but also increases the durability of the anti-fog plate itself.
As described above, it is possible to achieve extremely beneficial effects by making it possible to provide a synthetic resin anti-fogging plate that has desired properties such as heat resistance and impact resistance. Example As shown in Table 1, the substrate 1 has a thickness of 0.35~
Using various types of 3.0 mm thermoplastic resin sheets, apply various commercially available one-component moisture-curing polyurethane resin adhesives (3) on one side of the sheets in an amount of 2 to 2.
It was applied to a thickness of 5 μm (dry thickness) using a roll coater. Thereafter, cellulose-based double-sided anti-fog films 2 made of triacetylcellulose and cellulose propionate with thicknesses of 190 μ and 250 μ, which have been subjected to double-sided anti-fog treatment by a conventional method, are stacked on the adhesive-coated surface at room temperature. Samples of various anti-fogging plates were obtained by supplying and pressing between rubber rolls. On the other hand, as a comparative example, as shown in Table 1, an acrylic resin adhesive, a two-component polyurethane resin adhesive, and a vinyl resin adhesive were used. The sample was an attempt to adhere the film.

[Table] For the various anti-fog plate samples obtained in the above examples and comparative examples, the initial adhesive strength, water resistance, and boiling water resistance between the substrate and the anti-fog film were measured. The results are shown in Table 2. Incidentally, this measurement and evaluation were performed by the following method. (1) Adhesive strength Conducted according to the peel test method of JIS-K6744,
The evaluation is as follows: Measured value of 3.0 kg/2 cm width or more...○ Measured value of 3.0 kg/less than 2 cm width...△ Measured value of 1.0 kg/less than 2 cm width...× Unable to measure due to full-scale peeling...×× Ta. Durability and boiling water resistance were evaluated in the same manner. (2) Water resistance After immersing the test piece in room temperature distilled water for 30 days, the adhesive strength was measured according to (1) above. (3) Boiling water resistance The test piece was immersed in boiling water for 1 hour, and the adhesive strength after drying was measured according to (1) above.

[Table] As is clear from the results in Table 2 above, the anti-fog plates of the examples in which the substrate and the anti-fog film were bonded using a one-component moisture-curable polyurethane resin adhesive had an initial adhesive strength of It was confirmed that the material exhibited good adhesion performance even under severe conditions, and was a useful material suitable for applications such as ski goggles and motorcycle windshields.

[Brief explanation of drawings]

The drawing is a sectional view of a laminated synthetic resin anti-fogging plate obtained by the present invention. 1...Synthetic resin substrate, 2...Anti-fog film, 3
……glue.

Claims (1)

[Scope of Claims] 1. When obtaining a laminated anti-fog plate by adhering a double-sided anti-fog film or sheet made of cellulose-based synthetic resin that has been subjected to anti-fog treatment on at least one side of a synthetic resin substrate, the above adhesion is A method for producing a laminated synthetic resin anti-fog plate, characterized in that the process is carried out using an adhesive made of a one-component moisture-curing polyurethane resin. 2. The synthetic resin laminated anti-fogging plate according to claim 1, which uses a transparent or colored translucent thermoplastic synthetic resin sheet as the substrate. 3. A patent for using an anti-fogging film or sheet made of one selected from the group of diacetylcellulose, triacetylcellulose, cellulose acetate butyrate, and cellulose propionate, which has been treated with an alkali. A method for manufacturing a synthetic resin laminated anti-fogging plate according to claim 1 or 2. 4 As a substrate, cellulose resin, polyester resin, vinyl chloride resin, acrylic resin,
4. The method for producing a synthetic resin laminated anti-fogging plate according to claim 3, wherein a synthetic resin sheet made of one selected from the group of styrene resins and polycarbonate resins or a copolymer thereof is used.