JPH0120968B2 - - Google Patents

Description

[Detailed description of the invention]

<Industrial Application Field> The present invention relates to a method for manufacturing a vinyl chloride resin (hereinafter referred to as "PVC") product having a general part and an irregularly shaped part, such as side moldings and glass runs for automobiles. In this specification, the general section refers to a section that has the same cross section and can be formed by extrusion, etc., and the irregularly shaped section refers to a section that has a different cross-sectional shape or cross-sectional direction, such as the end section of a molding or the corner section of a glass run. This refers to the part that requires molding. <Prior art> Here, as the above-mentioned type of PVC product, as shown in Fig. 2, a general part 1 and an irregularly shaped part (terminal part) 2 are used.
This will be explained by taking a side molding having a side molding as an example. As shown in FIG. 1, this side molding is manufactured by applying adhesive to the joint end surface 1a of a general part 1 formed by extrusion or the like, and setting it in a mold 3.
In the cavity 4 for molding the irregularly shaped part formed in the mold 3
This is often done by injecting a PVC material (PVC compound) through an injection nozzle 5 (transfer is also acceptable) and integrating the end portion 2 at the same time as molding (see Japanese Patent Publication No. 56-47852, etc.). Although the end surface 1a is vertical in the illustrated example, it may be sloped from the viewpoint of increasing the adhesive surface. However, there is a waste of material. At this time, as the adhesive, acrylic/phenol adhesives and polyurethane adhesives, which are commercially available for PVC, have been used. <Problems to be solved by the invention> However, with these adhesives, it has been difficult to satisfy the demand for increased heat-resistant adhesive strength (particularly tensile strength) that has come with the recent proliferation of automobiles in extremely hot regions. . <Means for solving the problems> In order to solve the above problems, the present inventors
As a result of extensive research and consideration, we discovered that the adhesive to be applied to the joint end surfaces of the general parts should be a mixture of 0.5 to 20 parts by weight of PVC dissolved in 100 parts by weight of a good solvent for PVC. Here, if the blending amount of PVC is out of the above range, the required adhesive strength cannot be obtained in either case. Examples of the good solvent include ketones such as methyl ethyl ketone, acetone, and cyclohexanone, cyclic ethers such as tetrahydrofuran (THF), and nitrogen-containing compounds such as dimethylformamide, dimethylacetamide, and nitrobenzene. Furthermore, as the above-mentioned PVC, not only homopolymers but also copolymers of vinyl chloride, vinyl acetate, ethylene, etc. can be used, and these are produced by methods such as suspension and emulsion polymerization. Note that PVC is usually in the form of powder. <Function> In the case of highly crystalline polymers such as PVC,
The use of adhesives made of homogeneous plastics does not necessarily result in adhesion; for example, PVC
In the case of pipes, even if you use PVC powder THF as an adhesive, it will not adhere at all ("Adhesive Handbook 2nd Edition", published by Nikkan Kogyo Shimbun, Showa)
(Refer to page 93, published November 10, 1955). However, in this invention, by applying a specific amount of PVC dissolved in a good solvent as the adhesive applied to the joint end surface of the general part, high adhesive strength can be achieved between the general part and the irregularly shaped part. can get. The reason for this is not clear, but when the material is injected into the irregularly shaped part, the plasticizer in the material migrates to the PVC coating formed on the joint end surface of the general part, causing the PVC coating to become plasticized and crystallize. It is presumed that the adhesive strength decreases and high adhesive strength is obtained. <Example> General part 1 was obtained by extrusion molding (extrusion temperature: 170°C) into a square cross section (1 cm on each side) using the following PVC blend. PVC compound (parts: parts by weight) PVC homopolymer manufactured by Nipolitsu CM Chitsuso Co., Ltd.: = 2900) 100 parts DOP 80 parts heavy calcium carbonate 30 parts organotin stabilizer 2 parts Joining of general part 1 obtained above Each adhesive shown in Table 1 was applied to the end surface 1a with a brush and left for 1 to 3 hours (solvent evaporation). Subsequently, the general part 1 is set in a mold 3 as shown in FIG. 1, and then the following PVC compound is injected into the cavity 4 formed in the mold 3 to form the irregularly shaped part 2 and integrated at the same time. PVC compound (parts: parts by weight) Zeon 103EP8J (vinyl chloride/vinyl acetate copolymer manufactured by Nippon Zeon Co., Ltd.)) 100 parts DOP 100 parts heavy calcium carbonate 20 parts metal soap 3 parts epoxidized soybean oil 3 parts Above In this way, the PVC product in which the general part 1 and the irregularly shaped part 2 are joined is left for 24 hours at 23℃ and 65%RH atmosphere, and after the heat resistance test, it is left at 23℃ and 65%RH atmosphere for 24 hours→
80°C atmosphere for 240 hours → 23°C, 65% atmosphere for 1 hour. Using an Instron universal testing machine, the tensile adhesive strength was measured by pulling in the direction of the white arrow shown in Figure 2. We measured the The measurement results are shown in Table 1. <Effects of the Invention> As is clear from the test results in Table 1, the PVC products obtained by the method of the present invention exhibit superior performance when using conventional commercially available PVC adhesives, not only under normal conditions but also after heat resistance tests. It has much higher adhesive strength (especially tensile strength) between the general part and the irregularly shaped part. Therefore, PVC products such as side moldings and grass runs obtained by the method of the present invention can be used even in extremely hot regions.

【table】

【table】 [Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a general part set in a mold according to the present invention and the conventional method, and FIG. 2 is a partial cross-sectional view of a PVC product obtained by the present invention and the conventional method. 1... General part, 1a... Joint end surface of general part, 2
... Irregularly shaped part, 3... Mold, 4... Cavity for molding the irregularly shaped part, 5... Injection nozzle.

Claims (1)

[Scope of Claims] 1. When manufacturing a vinyl chloride resin product having a general part and an irregularly shaped part, the general part is molded by extrusion or the like, and after applying an adhesive to the joint end surface and setting it in a mold, the mold is In the method of injecting a vinyl chloride resin material into a cavity for molding an irregularly shaped part formed in a mold to mold and simultaneously integrate the irregularly shaped part, 0.5 to 20 parts by weight of a vinyl chloride resin is added as the adhesive to the vinyl chloride resin. A method for producing a vinyl chloride resin product, characterized by using a product dissolved in 100 parts by weight of a good solvent.