JPH01139244A - Introduction of steam into metallic mold - Google Patents

Abstract

PURPOSE:To enable production of a porous molded object with uniform weld strength and favorable quality, by a construction wherein steam can be jetted directly to foamable resin particles present in a cavity at a part fronting on a tip mouth part of a filling gun. CONSTITUTION:A cavity 30 is filled with a predetermined amount of foamable resin particles 50. With a plunger 44 moved forward to close a tip mouth part 42 of an injection pipe 41, steam is supplied into chambers 10a, 20a. The steam flows through steam holes 12, 22 into the cavity 30, and simultaneously, vent grooves 46 cut from the brim 42a of the tip mouth part 42 of the pipe 41 and radial slits 47 cut in a front face part 44a of the plunger 44 communicate with each other, so that the steam flows these parts to enter the cavity via the front side of the tip mouth part 42 of the pipe 41, whereby the resin particles present at a part fronting on the tip mount part 42 are effectively heated in the same manner as the resin particles present at other parts.

Description

[Detailed description of the invention] [Industrial application field]

The present invention provides that when pre-foamed resin particles or foamed resin particles (hereinafter collectively referred to as foamed resin particles) filled in the cavity of a mold are heated and fused using steam, water vapor is trapped in the foamed resin particle layer. This invention relates to an improved method for introducing water vapor into a molding die so that water vapor can be introduced evenly throughout the mold.

[Conventional technology]

In order to heat and fuse the foamed resin particles filled into the mold cavity, a number of steam holes were drilled in the mold wall on the side facing the mold cavity to allow water vapor to pass through and supply it to the mold chamber. A method has been adopted in which water vapor is introduced into the cavity and the foamed resin particles are heated by the vapor.

[Problems to be solved by the invention]

A filling gun for filling the cavity with foamed resin particles is installed on one of the male and female molds, specifically on the fixed female mold side. is attached to the mold so that it is flush with the mold wall facing the cavity. The tip opening of the filling gun is closed by the advance of the plunger when filling with the foamed resin particles is completed, so steam is not supplied to the foamed resin particles existing in the cavity portion facing the tip opening. Therefore, the foamed resin particles existing in the above portion are insufficiently heated. When foamed resin particles are fused together to form a porous molded product, there is a problem in that the strength of the fusion between the foamed resin particles is weak, which greatly affects the quality of the porous molded product.

[Means to solve the problem]

The present invention has solved the above problem, and its purpose is to supply heating steam to the cavity not only from the steam hole provided in the mold wall but also from the front face of the tip opening of the filling gun, which is blocked by the plunger. The foamed resin particles present in the cavity in the portion facing the tip opening are sufficiently heated in the same manner as the foamed resin particles present in other portions, and the foamed resin particles are strongly fused to each other. An object of the present invention is to provide an improved method for introducing water vapor into a molding die so that a porous molded product having uniform bonding strength over the entire product can be molded. Therefore, the above-mentioned object of the present invention is to provide a pair of male and female molds with a steam hole formed in the mold wall facing the cavity, and a tip end of a filling gun to be connected to the mold wall of one of the molds. In addition to introducing the steam supplied to the chamber of the mold into the cavity through the steam hole, the steam is also introduced into the mold wall and the side peripheral surface of the tip opening of the filling gun. According to the method of introducing water vapor into the mold, the water vapor is introduced into the cavity from the front side of the tip opening of the filling gun through a ventilation groove formed between the two and a slit provided in the front side of the plunger that closes the tip opening. achieved.

【Example】

First, a mold apparatus used for carrying out the method of the present invention will be explained. In the accompanying drawings, a pair of male and female molds is composed of, for example, a fixed mold 1o and a movable mold 20, and both molds 10
, 20, a large number of steam holes 12, 22 are bored in the mold walls 11, 21 on the side facing the cavity 30. On the fixed mold 10 side, a normal filling gun 40 is horizontally fixed at an injection tube 41, and the tip opening 42 of the injection tube 41 is flush with the mold wall surface facing the cavity 30. molded wall 11
It is connected to the. The filling gun 40 is provided with a supply port 43 connected to a supply hopper (not shown) for foamed resin particles, and a plunger 44 for opening and closing the tip opening 42 of the injection tube 41 is fixed to the tip of the piston rod 45. The foamed resin particles supplied from the raw material hopper are sent to the cavity 30 through the supply port 43 and the injection pipe 41, and when the cavity 30 is filled with the foamed resin particles, the plunger 44 moves forward and It is designed to close the end opening 42. Therefore, on the peripheral surface of the injection tube 41 on the side of the tip opening 42,
The fixed mold 10 is cut from the edge 42a of the tip opening 42.
A plurality of ventilation grooves 46 are provided in the front side 44a of the plunger 44 to communicate with the inside of the chamber 10a.
When the cavity is closed, slits 47 communicating with each of the ventilation grooves 46 are provided in a radial manner, so that water vapor supplied to the chamber 10a is introduced into the cavity 30 through the ventilation grooves 46 and the slits 47. There is. In the figure, 48 is a fixing flange for the injection tube 41, and 49 is a fixing bolt. Next, a method of the present invention using the mold apparatus having the above configuration will be explained. As shown in FIG. 1 of the accompanying drawings, when the cavity 30 is filled with a predetermined amount of foamed resin particles 5o and the plunger 44 is advanced to close the tip opening 42 of the injection tube 41, water vapor is released into the chambers 10a, 2Oa. At the same time, the water vapor is introduced into the cavity 30 through the steam hole 12, and at the same time, it is introduced into the cavity 3 from the front surface of the tip end portion 42 of the injection tube 41 through the ventilation groove 46 and the slit 47 of the plunger.
The present invention is carried out by introducing steam into the tube 42 and effectively heating the foamed resin particles present in the portion facing the tip opening 42 in the same manner as the foamed resin particles present in other portions. In this case, the water vapor supplied into the chamber 20a on the side of the movable mold 20 passes through the steam hole 22 and enters the cavity 30.
Needless to say, the foamed resin particles 50 are introduced into the foam and heated. The foamed resin particles used for molding include, for example, polystyrene, polypropylene, polyethylene, ethylene, etc.
Foamed resin particles of thermoplastic resins such as vinyl acetate copolymers, metal salts of ethylene/(meth)acrylic acid copolymers, α-methylstyrene/styrene/acrylonitrile copolymers, styrene-grafted polypropylene, and crosslinked resins thereof are used. There are nine. Further, foamed resin particles obtained from a mixture of these resins or a composition in which ethylene-propylene copolymer rubber or polyisobutylene rubber is blended with these resins or resin mixtures may be used, and the foamed resin particles have a bulk density of 10 to 90. g/Q and a particle size of 2 to 10 nwa are used. The foamed resin particles may or may not be crosslinked. As a method for producing foamed resin particles of thermoplastic resin as described above, for example, the resin is kneaded with a foaming agent in an extruder and extruded, and after exiting the nozzle of the extruder, the pressure is released to foam, and then cut. 1. Method for obtaining foamed resin particles without foaming ability;
Alternatively, resin particles are heated with stirring in a pressure-resistant container together with a dispersion medium such as water, a blowing agent, a dispersant, etc. at a temperature around the temperature at which the resin particles soften, and the resin particles are impregnated with the blowing agent before being placed in the container. A method of foaming the resin particles by opening one end and releasing the resin particles and dispersion medium into an atmosphere at a lower pressure than the inside of the container, or impregnating these foamed particles that do not have foaming ability with a foaming agent, A method in which pressurized gas is injected into the cells of foamed particles to impart secondary foaming ability, and a method in which foamable resin particles containing a foaming agent such as polystyrene, styrene-grafted polypropylene, styrene-grafted polyethylene, etc. are heated and pre-foamed. etc. Effects of the Invention 1 The present invention is as described above, and since water vapor can be directly injected to the foamed resin particles existing in the cavity in the portion facing the tip opening of the filling gun, the foamed resin particles in this portion are free from other particles. As with the foamed resin particles present in the area, steam heating is carried out sufficiently, completely eliminating problems such as weak fusion strength, and producing high-quality porous molded products with uniform fusion strength. It is extremely effective.

[Brief explanation of the drawing]

The drawings show a mold device used for carrying out the present invention, in which Fig. 1 is a partially omitted sectional view, Fig. 2 is a perspective view showing the tip and mouth side of the filling gun, and Fig. 3 is the same as above. FIG. 3 is a perspective view showing a portion of the plunger. In the figure, 10 is a fixed mold, loa is a chamber, 11 is a mold wall, 12 is a steam hole, 20 is a movable mold, 20a is a chamber, 21 is a mold wall, and 22 is a steam hole. 30 is a cavity, 40 is a filling gun, 41 is an injection tube, 4
2 is a tip opening, 44 is a plunger, 44a is a front part,
46 is a ventilation groove, and 47 is a slit.

Claims (1)

[Claims] This molding process is carried out using a molding mold in which a steam hole is bored in the mold wall on the side facing the cavity of a pair of male and female molds, and the tip end of a filling gun is connected to the mold wall of one of the molds. In addition to introducing the water vapor supplied to the chamber of the mold into the cavity through the steam hole, the water vapor is introduced into the cavity through the ventilation groove formed between the side peripheral surface of the tip opening of the filling gun and the mold wall and the tip opening. 1. A method for introducing water vapor into a molding die, the method comprising introducing water vapor into a cavity from the front face of a tip opening of a filling gun through a slit provided in the front face of a plunger that closes the water vapor.