JP2013151105A - Method of molding thermoplastic resin sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of molding a thermoplastic resin sheet, wherein adhesion between the thermoplastic resin sheet and a mold is high even when a thermoplastic resin is hard.SOLUTION: A peripheral edge part 1a of a thermoplastic resin sheet 1 is held by a clamp member 2 (Fig. (a)), a molding part 1b of the thermoplastic resin sheet 1 heated to such a degree that it is softened is along a mold 3 and is vacuum sucked via a suction hole provided in the mold 3 (Fig. (b)), and the thermoplastic resin sheet 1 is brought into close contact with the mold 3 to produce a molded article P (Fig. (c)). A portion 4 having a lower strength than the peripheral edge part 1a is provided inside the peripheral edge part 1a of the thermoplastic resin sheet 1 held by the clamp member 2 and outside a portion in contact with the mold 3 by fusion or the like, for example.

Description

  The present invention relates to a method for molding a thermoplastic resin sheet, and more particularly to a method for molding a thermoplastic resin sheet suitable for molding a thermoplastic resin highly filled with an inorganic material such as graphite.

  Conventionally, as a method for forming a thermoplastic resin sheet, there is known a method in which a sheet-shaped thermoplastic resin is evacuated in a mold to obtain a required shape along the mold (for example, Patent Document 1).

  Further, the present applicant has proposed a combustion-resistant sheet using a thermoplastic resin highly filled with an inorganic material such as graphite (Patent Document 2).

  As shown in FIG. 3, a conventional thermoplastic resin sheet is formed by holding a peripheral portion of a thermoplastic resin sheet (11) with a clamp member (2) and heating it to such an extent that it is softened ( 11) is placed along the mold (3), and the thermoplastic resin sheet (11) is brought into close contact with the mold (3) by vacuum and / or compressed air.

Japanese Patent Laid-Open No. 2007-223096 JP 2011-140209 A

  When the thermoplastic resin described in Patent Document 2 is molded using the conventional thermoplastic resin sheet molding method, the thermoplastic resin is hardened with high inorganic filling. There has been a problem that the resin sheet (11) is difficult to adhere to the mold (2) (for example, the portion indicated by A in FIG. 3 (b) is rounded).

  An object of the present invention is to provide a method for forming a thermoplastic resin sheet having high adhesion between the thermoplastic resin sheet and a mold even when the thermoplastic resin is hard.

  According to the method of molding a thermoplastic resin sheet according to the present invention, the peripheral portion of the thermoplastic resin sheet is held by a clamp member, and the thermoplastic resin sheet heated to a degree of softening is placed along a mold, and vacuum and / or compressed air is used. In the molding method of the thermoplastic resin sheet that is molded by closely attaching the thermoplastic resin sheet to the mold, on the inner side of the peripheral edge held by the clamp member of the thermoplastic resin sheet and on the outer side of the part in contact with the mold, A portion having a lower strength than the peripheral edge portion is provided.

  For example, in the case of a rectangular sheet, the “low-strength portion” may be provided along the entire circumference of the peripheral edge, or may be provided only in the longitudinal direction or only in the lateral direction. The “low strength portion” can be a groove shape, a cut (perforated shape, etc.), a fused portion, etc., at the time of extrusion of the thermoplastic resin sheet or after extrusion of the thermoplastic resin sheet and before molding, It is provided by appropriate means.

  As the mold and the clamp member, known appropriate configurations including these moving means can be used. In addition to the configurations described above, for example, a known appropriate configuration can be used for a heating unit, a vacuum and / or a pneumatic unit for softening the thermoplastic resin sheet. The configuration (material, etc.) of the thermoplastic resin sheet is not particularly limited.

  According to the method for molding a thermoplastic resin sheet of the present invention, the thermoplastic resin sheet is formed by providing a portion having a lower strength than the peripheral portion inside the peripheral portion held by the clamp member of the thermoplastic resin sheet. When the thermoplastic resin sheet is pulled in the step of closely contacting the mold, the thermoplastic resin sheet breaks at a portion where the strength is lower than that of the peripheral portion, whereby the tension from the peripheral portion held by the clamp member is heated. It does not act on the molded part of the plastic resin sheet. For this reason, the molding part of a thermoplastic resin sheet becomes a thing easily deform | transformed, and the adhesiveness of a thermoplastic resin sheet and a metal mold | die is improved. Thus, even if the thermoplastic resin is hard, it can be molded without hindrance.

  The method for molding a thermoplastic resin sheet of the present invention is suitably used for molding a resin composition highly filled with inorganic materials (graphite, aluminum, etc.), for example. For example, a vinyl chloride resin composition containing 15 to 200 parts by weight of graphite with respect to 100 parts by weight of all resin components is excellent as a material for a flame resistant sheet because of its excellent combustion resistance. However, the moldability (adhesiveness of the thermoplastic resin sheet to the mold) is lowered due to high graphite filling. To increase the adhesion of the thermoplastic resin sheet to the mold, it is possible to increase the distance from the clamp to the mold, but this distance may not be sufficient due to equipment problems. is there. Even in such a case, according to the method for molding a thermoplastic resin sheet of the present invention, the problem of lowering the adhesion of the thermoplastic resin sheet to the mold is solved, and the manufacture of the flame resistant sheet is easy. Become. The thermoplastic resin sheet (combustion resistant sheet) is not limited to a single layer, and may be a laminate of a plurality of layers.

  In addition, the thermoplastic resin sheet molding method of the present invention eliminates the need to increase the distance from the clamp to the mold in order to increase the adhesion of the thermoplastic resin sheet to the mold. By applying this method to a resin composition that has not been made, the equipment can be downsized.

  According to the method for molding a thermoplastic resin sheet of the present invention, the adhesion between the thermoplastic resin sheet and the mold is high, and therefore, even when the thermoplastic resin is hard, a clamp is used to increase the adhesion. Adhesion can be enhanced without increasing the distance from the periphery of the mold to the periphery of the mold.

Drawing 1 is a figure (figure seen from the front) showing typically one embodiment of a molding method of a thermoplastic resin sheet by this invention. FIG. 2 is a diagram (view from a plan view) schematically showing one embodiment of a method for molding a thermoplastic resin sheet according to the present invention. FIG. 3 is a diagram (seen from the front) schematically showing a conventional method for forming a thermoplastic resin sheet.

  Embodiments of the present invention will be described below with reference to the drawings.

  As shown in FIG. 1, the thermoplastic resin sheet molding method according to the present invention holds the peripheral edge (1a) of the thermoplastic resin sheet (1) with a clamp member (2) (FIG. 1 (a)) and softens it. The molded part (1b) of the thermoplastic resin sheet (1) heated to such a degree is placed along the mold (3) and vacuumed through a suction hole (not shown) provided in the mold (3). By sucking (FIG. 1 (b)), the molded product (P) is obtained by bringing the thermoplastic resin sheet (1) into close contact with the mold (3) (FIG. 1 (c)). The molded product (P) is removed from the mold (3) and cooled, and then the periphery is cut off to obtain a product.

  This method for forming a thermoplastic resin sheet is suitable for vacuum forming a thermoplastic resin highly filled with an inorganic material such as graphite or aluminum.

  In the method for molding a thermoplastic resin sheet according to the present invention so as to be suitable for the use of a thermoplastic resin highly filled with the inorganic material, as shown in FIG. A portion (10) having a lower strength than the peripheral edge (1a) is provided inside the peripheral edge (1a) held by the clamp member (2).

  As shown in FIG. 2, the portion (10) having a lower strength than the peripheral portion (1a) is a rising portion (3a) of the mold (3), that is, the mold (3) of the thermoplastic resin sheet (1). It is provided on the outer side of the portion that contacts with.

  The portion (10) having a low strength may have a groove shape as illustrated in FIG. 1 (a), or may have a cut (for example, a perforation shape). These may be provided, for example, during the extrusion process of the thermoplastic resin sheet (1). In addition, before the molding step, a portion (10) having low strength may be formed by adding a step of providing a fusion part in which the resin is appropriately fused by hot press molding.

  As shown in FIG. 1 (b), the molded part (1b) of the thermoplastic resin sheet (1) is aligned with the mold (3) because there is a part (10) having a lower strength than the peripheral part (1a). In the process, when the tension from the peripheral portion (1a) held by the clamp member (2) is applied to the molded portion (1b), the low strength portion (10) is broken and cleaved, and FIG. ), A molded product (P) having high adhesion to the mold (3) is obtained.

  In FIG. 2, a low-strength portion (10) is provided along the entire circumference of the peripheral edge portion (1a) of the thermoplastic resin sheet (1), but the present invention is not limited to this. For example, it may be provided only on two opposing sides (only in the vertical direction and only in the horizontal direction).

  Also, in the above, “vacuum forming” in which vacuum suction is performed, but instead of this, “pressure forming” in which the thermoplastic resin sheet is brought into close contact with the mold by supplying compressed air (compressed air) or vacuum suction. Also in the “vacuum and pressure forming” in which the thermoplastic resin sheet is brought into close contact with the mold by using both the compressed air supply and the compressed air supply, the adhesiveness between the thermoplastic resin sheet and the mold can be improved in the same manner as described above.

(1) Thermoplastic resin sheet
(1a) Perimeter
(1b) Molding part
(2) Clamp member
(3) Mold
(10) Low strength part

Claims (1)

By holding the peripheral edge of the thermoplastic resin sheet with a clamp member, placing the thermoplastic resin sheet heated to the extent that it is softened along the mold, and adhering the thermoplastic resin sheet to the mold by vacuum and / or compressed air In the molding method of the thermoplastic resin sheet to be molded,
Molding of a thermoplastic resin sheet characterized in that a portion having a lower strength than the peripheral portion is provided inside the peripheral portion held by the clamp member of the thermoplastic resin sheet and outside the portion in contact with the mold. Method.

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