JPH026113A - Injection mold of molded object with porous elastic member - Google Patents

Abstract

PURPOSE:To strengthen the connection of the sheet preventing resin from being soaked to a resin molded object, while productivity is contrived to be improved by injecting molten synthetic resin from the projected gate inserted into the hole of a porous elastic member, into the recessed part provided in the mold of the opposite side to the side where the projected gate is provided. CONSTITUTION:An injection mold is composed of a top force 10 and a bottom force 12, and a cavity 14 is formed between their die faces. A sprue 16 and a hot runner 18 are provided in the top force 10, and on the tip part of the runner 18, a projected gate 20 and a normal gate 22 are provided. The tip part of the normal gate 22 is arranged flush with the parting face of the top force 10 and the tip part of the projected gate 20 is arranged at the projected level by prescribed amount from the parting face of the top force 10. A recessed part 24 is provided at the position corresponding to the projected gate 20 of the bottom force, and porous elastic members 26, 28 are arranged in the cavity 14 of the bottom force 12. Molten resin is injected from the surface 16 in the state where the projected gate 20 is being inserted into the hole of the porous elastic member 26. Consequently, the resin flows uniformly into the space between the elastic member and the bottom force, and an excellent molded object is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION B) Industrial Application Field The present invention relates to an injection mold for a molded article with a porous elastic member.

(b) Prior Art A technique for integrally joining a soft foam sheet (porous elastic member) to one or both sides of a synthetic resin molded product is disclosed in, for example, Japanese Patent Laid-Open No. 61-24939. That is, the above-mentioned product is obtained by laminating a synthetic resin molded product onto a soft foam sheet to which a resin seepage prevention sheet has been attached in advance, and then performing stamping molding. As a result, the molded product and the soft foam sheet are integrally joined via the resin seepage prevention sheet, and at the same time, the resin is prevented from seeping into the soft foam sheet.

(c) Problems to be Solved by the Invention However, the technique for manufacturing a synthetic resin molded article with a porous elastic member as described above has the following problems. That is, it is necessary to laminate the synthetic resin on the surface of the resin seepage prevention sheet and then perform stamping, which complicates the process and makes it difficult to improve production efficiency. Further, although it is possible to obtain a two-dimensional molded product, it is difficult to manufacture a three-dimensional molded product. Furthermore, the bonding strength between the resin seepage prevention sheet and the resin molded product may not be sufficient.

In order to solve the above-mentioned problems, the patent application
No. 1-279245, a porous elastic member is inserted between molds, the porous elastic member is compressed by clamping the molds, and then a molten synthetic resin is injected to compress one side or two of the porous elastic members. A method is shown in which a molten synthetic resin is flowed between porous elastic members to obtain a molded article integrally joined to the porous elastic members. This certainly makes it possible to solve the above problems. However, this case also has the following problems. In other words, there is no problem in molding a molded product on the side of the porous elastic member facing the gate, or molding the molded product between two porous elastic members, but on the gate installation side of the porous elastic member When molding a synthetic resin molded product on the opposite side, the gate is moved to the side of the porous elastic member and the submarine gate is used. However, if this is done, the mold becomes larger and more complicated, and problems arise such as taking out the runner of the submarine gate and regenerating the runner. The present invention aims to solve these problems.

(d) Means for Solving the Problems The present invention provides melting from a protruding gate inserted into a hole of a porous elastic member into a recess provided in a mold on the opposite side of the mold on the side where the protruding gate is provided. The above problem is solved by injecting synthetic resin. That is, in the injection molding mold for a molded article with a porous elastic member according to the present invention, one mold is provided with a protruding gate for injecting molten resin into the cavity, and the other mold has a corresponding protruding gate. A recess is provided at the position, and the protruding gate has a diameter that fits into the hole provided in the porous elastic member and a length that passes through the hole, and the recess does not interfere with the protruding gate in the mold clamping state. diameter and depth.

(e) In the active mold clamping state, the protruding gate passes through the hole in the porous elastic member, and the tip of the protruding gate enters the recess of the other mold. When molten synthetic resin is injected from the protruding gate in this state, it flows between the mold on the side where the recess is provided and the porous elastic member, further compresses the porous elastic member and spreads into the cavity. , it is possible to obtain a molded product that is firmly joined to the porous elastic member. As mentioned above, the molten synthetic resin flows through the recess, so the porous elastic member is caught in the flow of the molten synthetic resin and deforms, or the molten synthetic resin creates a tunnel inside the porous elastic member and flows. As a result, a synthetic resin molded product can be formed on the surface of the porous elastic member opposite to the side where the gate is installed, and a product having the desired function and appearance can be obtained.

(f) Example FIG. 1 shows an injection mold for a molded article with a porous elastic member according to the present invention. This injection mold includes an upper mold 10 and a lower mold 1.
2. A cavity 14 is formed in the mating surfaces of the upper mold 10 and the lower mold 12. The upper mold 10 is provided with a sprue 16 and a hot runner 18 for receiving the molten synthetic resin, and a protruding gate 20 (although only one is shown) is provided at the tip of the hot runner 18. , in fact two gates are provided) and a gate 22 is normally provided. - Normally, the tip of the gate 22 is arranged so as to be flush with the parting surface of the upper mold 10. On the other hand, the tip of the protruding gate 20 is arranged so as to protrude by a predetermined amount beyond the parting surface of the upper mold IO. A recess 24 is provided in the lower die 12 at a position corresponding to the protruding gate 20. As shown in detail in Figure 2, the diameter of the fourth part 24 (12 mm) is the diameter of the cage 2o (9 mm).
The depth of the recess 24 is such that the tip of the gate 20 does not interfere with the bottom of the recess 24 when the mold is clamped (3 mm). Note that the recessed portion 24 may have a tapered shape extending outward.

Next, the process of manufacturing a product using this injection mold will be explained. Two porous elastic members 26 and a porous elastic member 28 are placed in the cavity 14 of the lower mold 12 in the opened state.
(Both are made of soft polyurethane foam, etc.). Next, the mold is clamped to compress the porous elastic member 26 and the porous elastic member 28. As a result, the porous elastic member 26 and the porous elastic member 28 have a thickness of 8 mm in their natural state.
is compressed to a thickness of 2.8 mm. That is, the thickness is compressed to about 35%. Note that the porous elastic member 26 is provided with a hole through which the protruding gate 20 passes, and in the mold clamping state, the protruding gate 20 passes through the hole of the porous elastic member 26 and slightly enters the four parts 24. It becomes. In this state, the molten synthetic resin (40
% mica-containing polypropylene) at low pressure and low speed. The molten synthetic resin is filled into the cavity 14 through the protruding gate 20 and the normal gate 22 via a hot runner. The molten synthetic resin filled from the protruding gate 20 flows into the recess 24 and then flows between the compressed porous elastic member 26 and the lower die 12, further compressing the porous elastic member 26 by the resin pressure and melting the resin. A channel is formed and the space between the mold 12 and the porous elastic member 26 is uniformly filled. The porous elastic member 26 is compressed to a thickness of about 0.3 mm by this resin pressure, and is pressed against the upper mold lO side. Therefore, the porous elastic member 26 does not move due to the flow of resin. In this state, the porous elastic member 26 has been compressed to about 4% of its initial thickness of 1. Furthermore, since the molten synthetic resin flows from the recess 24 between the porous elastic member 26 and the lower mold 2,
The ends of the holes in the porous elastic member 26 do not turn over and get caught up in the resin flow, and the resin flow creates a tunnel-like flow path inside the porous elastic member 26 and flows inside the porous elastic member 26. This prevents molten synthetic resin from entering. The molten synthetic resin that has flowed into the gap between the porous elastic member 26 and the lower mold 12 slowly permeates into the porous elastic member 26 from the surface of the porous elastic member 26 which has been compressed and densified. Then, the synthetic resin molded product and the porous elastic member 26 are firmly joined together by being cooled and solidified.

On the other hand, the molten synthetic resin normally injected from the gate 22 flows between the upper mold 10 and the porous elastic member 28, and a synthetic resin molded product is formed on the upper surface side of the porous elastic member 28 by the same operation as described above. do. After injection of the molten synthetic resin is completed, it is cooled and solidified, then the mold is opened and the molded product is taken out. The compressed porous elastic member 26 and porous elastic member 28 return to their natural state, and a product as shown in FIGS. 3 and 4 can be obtained. This product is an airflow control valve for automotive air conditioners. The obtained plate thickness was 2.5 mm, and the thickness of the porous elastic member 26 and the porous elastic member 28 was 6 m.
It became m.

(G) As described in detail, according to the present invention, the protruding gate on one mold side is made to protrude beyond the parting surface, a recess is provided on the other mold side, and the protruding gate is made of porous elastic material. Since the molten synthetic resin is injected while the porous elastic member is inserted into the hole, the molten synthetic resin flows uniformly through the gap between the porous elastic member and the other mold, and a good molded product can be obtained. In other words, it is possible to prevent the porous elastic member from being caught in the flow of the molten synthetic resin and from forming a tunnel-like resin passage inside the porous elastic member, thereby obtaining a product with the desired appearance and function. I can do it.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the injection mold of the present invention, FIG. 2 is an enlarged view of the portion 0 in FIG. 1, and FIG. 3 is a plan view of the product obtained by the injection mold shown in FIG. FIG. 4 is a side view of the product shown in FIG. 3. 10... Upper mold, 12... Lower mold, 14... Cavity, 20... Protruding gate, 22... Normal gate, 2
4... Concavity, 26.28... Poroelastic member. Patent applicant Shimizu Industries Co., Ltd. Figure 2 Figure 2 Figure 2

Claims (1)

[Scope of Claims] Used for molding a synthetic resin molded product in which a porous elastic member is integrally joined by injecting molten resin into the cavity while the porous elastic member is compressed within the cavity of a mold. In an injection mold for a molded article with a porous elastic member, one mold is provided with a protruding gate for injecting molten resin into the cavity, and the other mold is provided with a recess at a position corresponding to the protruding gate. The protruding gate has a diameter that fits into a hole provided in the porous elastic member and a length that passes through the hole, and the recess has a diameter and depth that does not interfere with the protruding gate in the mold clamping state. An injection mold for a molded product with a porous elastic member, characterized by having a