JPH0253383B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for manufacturing laminated glass characterized by heat-treating an interlayer film using far infrared rays, and more specifically to a method for efficiently and continuously performing heat treatment required in the manufacturing process of laminated glass using far infrared rays. Regarding the method of implementation. Conventionally, there are a large number of methods for heating articles, and these methods have been used in practice. Typical examples include hot air heating using an oven or the like, steam heating typified by an autoclave, infrared heating, far infrared heating, and high frequency heating. Each of these has advantages and disadvantages, and has been used depending on its intended use. In addition, the polyvinyl butyral resin intermediate material that has been most commonly used as an interlayer film for laminated glass is a thermoplastic resin, and its crimping involves a preliminary crimping process and a main crimping process, but the main crimping process involves heating. Autoclaves are most commonly used because of the pressure required. However, autoclaves have the following drawbacks due to their nature.
A huge autoclave is required for laminated glass, and the heat capacity of the autoclave itself is extremely large, requiring a huge amount of energy.
Autoclaves cannot perform continuous processes and have very poor productivity. Therefore, a continuous and efficient heating method alternative to autoclaves and the like has been desired. However, the interlayer film material mainly composed of ethylene-vinyl acetate copolymer (hereinafter abbreviated as EVA) used in the present invention is disclosed in Japanese Patent Application No. 56-80915 and No. 56-136970.
As disclosed in , it is a photocurable resin made by blending peroxide or photosensitizer with EVA, and it is a material that does not cause defects such as blistering when heated, and develops adhesive strength as it hardens. Because it does not require pressure. After intensive research into a continuous and efficient heating method using such EVA-based intermediate materials, we found that the absorption wavelength of glass and intermediate materials is mostly in the far-infrared region (2.5 to 50μ), and when irradiated with far-infrared rays, It is possible to heat to the desired temperature in an extremely short period of time, and because the temperature of EVA-based intermediate material and glass increases faster due to far infrared rays, it is possible to sandwich the material between two glasses like laminated glass. In this case, the inventors have discovered that the intermediate material can be heated extremely efficiently and have arrived at the present invention. The manufacturing process for laminated glass usually involves a preliminary pressure bonding process in which the air interposed between the glass and the film is expelled and the film is softened by heating to press the glass and the film together, and a main pressure bonding process in which the bond is completed at even higher temperatures and pressures. It is broadly divided into Therefore, in the pre-press bonding process, both the thermoplastic material and the heat or photo-curable material are pressed against the glass by softening the film, expelling the air present in between, and the method of the present invention is used as a heating method for this purpose. be able to. In addition, this crimping process is not suitable for materials that require heat and pressure, such as polyvinyl butyral resin, but the above
The method of the present invention can be suitably used for heat- or photo-curable materials containing EVA as a main component because they can be compressed and heat-cured only by heating without applying pressure. Also EVA
In order to improve the transparency of photocurable resins whose main ingredients are It is also possible to install a far-infrared heater, which is the best method. The far-infrared heater used in the present invention may be any heater that efficiently emits far-infrared rays with a wavelength of 2.5 to 50μ, such as rod heaters, lamp heaters, panel heaters, socket heaters, etc. . The purpose can be achieved by continuously conveying the material using a conveyor or the like into a furnace equipped with these heaters. Further, in the pre-press bonding process, there are usually a rubber bag method, a hot roller method, a peripheral sealing method, etc., but any of these methods can be applied, and in particular, it is possible to heat the product while it is still in a rubber bag. According to the present invention, EVA-based intermediate materials can be heated continuously and efficiently by using a conveyor etc. not only in the heat treatment in the pre-pressing process but also in the main pressing process, which can significantly improve productivity. . Next, the present invention will be specifically explained with reference to Examples. Example 1 EVA intermediate material of composition A (thickness 0.5×
300 x 300 mm), and in order to measure the temperature of the intermediate material, a copper-constantan thermocouple with a diameter of 0.3 mm was placed on the interlayer film, placed in a rubber bag, and set to 110°C in advance while degassing. The sample was passed through a far-infrared heater furnace (Minijet manufactured by Jyard Co., Ltd.) at a speed of 20 minutes. When the laminated glass was then removed from the rubber bag, the air had been completely removed and a thermocouple had been inserted in the center of the laminated glass. Two pieces of this were made and used for temperature measurement. Formulation A Evaflex 250 100 Diwalnut peroxide 1 Stearic acid 0.5 γ-glycidoxypropyltrimethoxysilane
0.5 Also, an EVA material having a thickness of 3 mm and composition A was put into a 6 mm thick mold with the thermocouple sandwiched in the center and pressed at 110°C to produce a material with a thermocouple in the center. A sample with a thermocouple sandwiched between glass and a 6 mm thick sample with a thermocouple inserted in the center were placed in the center of a far-infrared furnace preset at 160°C, and the temperature rise was measured. Another sample with a thermocouple sandwiched between two sheets of laminated glass was placed in an oven set at 160°C, and the temperature rise was measured. The table below compares the time it took for the three samples to reach 160°C.

【table】

[Table] Therefore, it can be seen that the temperature rise of the intermediate material matched to the glass is the fastest. Example 2 The absorption spectra of EVA intermediate material of Formulation A with a thickness of 0.5 mm and float glass with a thickness of 3 mm were measured (Figures 1 and 2). For reference, the relative energy intensities of an infrared lamp and a far-infrared lamp are shown in Figure 3. This shows that both glass and EVA materials absorb almost 100% of far-infrared rays, indicating that the method of the present invention is an efficient method.

[Brief explanation of drawings]

Figure 1 shows the absorption spectrum of the EVA intermediate material sheet, Figure 2 shows the absorption spectrum of two sheets of glass, and Figure 3 shows the relationship between the relative energy intensity and wavelength of an infrared lamp and a far-infrared lamp.

Claims (1)

[Claims] 1. An intermediate material mainly composed of ethylene-vinyl acetate copolymer sandwiched between two glass plates.
A method for manufacturing laminated glass, characterized in that heat treatment is performed in a preliminary pressure bonding process and a water pressure bonding process using far infrared rays having a main wavelength range of ~50μ. 2. Claim 1, wherein the intermediate material mainly composed of ethylene-vinyl acetate copolymer is a heat- or photo-curable material prepared by blending peroxide or photosensitizer with ethylene-vinyl acetate copolymer. The method for manufacturing the laminated glass described.