JP2950656B2 - Molding method of foamed resin molded product - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for molding a foamed resin molded product using a mold, and more particularly to an improvement in a so-called closed injection molding method for injecting a resin liquid into a cavity in a mold closed state for molding.

[0002]

2. Description of the Related Art Conventionally, for example, a foamed resin molded product such as an instrument panel as an interior part of a vehicle is foamed by injecting, for example, a two-component foamed resin solution into a mold and foaming the foamed resin. Is to be molded into a molded product with
Such a molding method includes, for example, Japanese Utility Model Laid-Open No. 1991311.
No. 6,098,067, a method of injecting a resin liquid into a cavity in a mold closed state called a so-called closed type mold, and a method of opening a resin liquid in a mold open state called an open type mold as disclosed in JP-A-63-239013. And then closing the mold. In the closed type, the mold is closed from the beginning, so that a resin material having a faster reaction start time and a faster reaction rate than the open type can be used, so that there are advantages such as a shorter cycle time. .

[0003]

However, in the case of the closed type, there is a drawback that when the size of the product increases, defective filling tends to occur. In other words, in the case of the open type, the degree of freedom of the injection position of the resin is relatively large, and even in the case of a large product, it is possible to inject from a desired position, so that poor filling is unlikely to occur. For example, when injecting from one end of a cavity with a long resin flow length, the resin that is progressively filled while foaming and solidifying in the cavity does not spread to the other end, resulting in insufficient filling. It is. Therefore, if the injection amount of the resin liquid is increased in order to eliminate such insufficient filling, increase in cost, generation of voids (vacancies generated inside the molded product) due to increase in internal pressure, and prevention of weight reduction of the molded product due to increase in density are hindered. On the other hand, if the resin liquid injection portion is provided at the center of the mold or the like, a significant change in the design of the mold or the like is involved, which is not preferable.

[0004]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is to introduce a resin liquid to a desired portion in a mold, and then to foam-fill the entire portion of the mold from the desired portion. I did it. In other words, after arranging a runner nest in the mold and closing the mold by connecting a desired portion of the mold with the resin injection portion of the mold, a foamed resin liquid is injected from the resin injection portion,
The resin liquid was introduced into a desired location in the mold via a runner insert, and was filled and molded in the entire area of the mold in a subsequent foaming step. Further, in the case of a foamed resin molded product having a core material, the runner nest is provided integrally with the core material.

[0005]

The resin liquid, for example, is once guided to the center of the molded product by the insert of the runner and foamed and filled from this position to the whole area in the mold. Can be reduced by half. In addition, the flow length of the resin can be further reduced by branching the runner nest as necessary to form a distribution channel. For this reason, underfilling is unlikely to occur. In the case of a molded product having a core material, the work of setting the mold in a mold is facilitated by forming the runner nest integrally with the core material in advance.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Before describing the molding method of the present invention, a conventional molding method will be described first with reference to FIGS. Here, FIG. 5 is a longitudinal sectional view of the foam molding die apparatus, and FIG.
FIG. 6 is a sectional view taken along line CC of FIG. 5.

A vehicle instrument panel or the like is formed by a so-called injection foaming method using a foam molding die 50 as shown in FIGS. That is, foaming is performed while pouring into a mold while mixing and mixing various raw materials necessary for forming a foam. In the mold 53 of the mold 50, the lower mold 51 side is set before the mold is closed. A foundation 55 (core material) is set on the upper mold 52 side, and the outer skin 54 is integrally molded with the foamed resin 60 injected between them.

The raw material to be injected is usually two liquids. For example, in the case of a urethane foam, the two liquids of polyether and isocyanate are mixed through a mixer and foamed by pouring into a mold 53 to form a foamed structure. Form the foam that you have.

The resin liquid material is injected from a resin injection portion 56 on the side surface of the mold, and a narrow horizontal injection passage 58 is formed.
After passing, the resin is filled while spreading from the filling diffusion portion 59 into the inside of the molded product. However, when the molded product becomes large, the resin flow length after the filling diffusion portion 59 becomes long and solidifies in the middle. However, there is a problem that the end of the molded product is not sufficiently filled.

The present invention has been devised to solve the above-mentioned problems by devising a molding method which does not significantly alter the structure of a conventional mold apparatus. The molding method will be described below with reference to FIGS. FIG. 1 is a longitudinal sectional view of the mold apparatus of the present invention, taken along the line DD in FIG. 2, and FIG.
FIG. 3 is a sectional view taken along line BB of FIG. 1, and FIG. 4 is a view of another embodiment.

The foam molding die of the present invention is used, for example, when performing injection molding of urethane foam by closed molding, and is used to fill a mold 3 in which a lower mold 1 and an upper mold 2 are defined in a closed state. The resin injection section 6 is configured by a side injection method, that is, a current method.

In the same manner as in the current system, a skin 4 having, for example, a textured pattern, a squeezed pattern, etc. is set on the lower mold 1 side, and a foundation 5 as a core material is set on the upper mold 3 side, and foaming is performed between them. Although a resin 10 liquid material is injected and integrally molded, a trough-shaped runner nest 7 is used unlike the current method.

In other words, the runner insert 7 is for guiding the resin liquid injected from the resin injection section 6 to a desired location in the mold 3. In the case of the embodiment, as shown in FIG. The resin liquid from 8 is branched right and left and divided into two auxiliary flow paths (runners) 7a, 7a. Then, the outlets of the two branched auxiliary flow paths are configured as filling and diffusing portions 9, 9 so as to communicate with both ends in the length direction of the molded product and substantially in the center in the width direction.

In the case of the embodiment, as shown in FIG. 3, the runner nest 7 is arranged outside the foundation 5,
Outer projections such as reinforcing ribs formed outside the foundation 5 among the molded products are used.
For molded products that do not require such outward projections,
As shown in FIG. 4, it may be provided on the inner side of the molded product, and no special work is required on the mold side. The position and number of the runner nests 7 and the communication position of the filling / diffusion section 9 are arbitrary, and are freely set in consideration of the size, shape, and the like of the molded product.

In the case of the embodiment, the runner nest 7
Is formed integrally with the foundation 5, but of course the foundation 5 and the skin 4 are not essential requirements, and may be formed separately from the foundation 5.

The molding method having the above-described configuration, and the operation and effect thereof are as follows. After setting the skin 4 and the foundation 5 in the mold 3 and closing the mold, a resin liquid is injected from the resin injection part 6. At this time, an after-mixer (not shown) is provided upstream of the resin injection section 6, and a resin liquid usually composed of two liquids is mixed and injected.

After passing through the injection path 8, the resin liquid is guided to the filling diffusion sections 9, 9 through the auxiliary flow paths 7a, 7a of the runner inserts 7, 7. During this time, the foaming and solidification of the resin liquid starts from the stage of flowing through the injection path 8, but the injection path 8, the auxiliary flow path 7
A material having a reaction start time such that the foaming reaction does not start rapidly while flowing through a is selected, and solidification does not proceed during this time. Then, the resin liquid is simultaneously foamed and filled from the filling diffusion portions 9 toward the inside of the molded product.

For this reason, the resin liquid is foam-filled from the substantially central portion of the molded product, so that the distance to the end of the cavity is shortened. In addition, the resin liquid is simultaneously injected from two places and quickly filled. That is, molding failure due to insufficient filling does not occur.

[0019]

As described above, according to the molding method of the present invention, the same filling effect as in the open injection can be obtained in the closed injection foaming molding while maintaining the current side injection mold. For this reason, the acceptance rate of the molded product is improved, and the molding can be performed several cycles earlier than the open injection. In addition, since the runner nest is formed integrally with the core material, the disposing work in the mold can be performed extremely smoothly. Further, since the existing mold can be used in almost the same form, it is possible to obtain effects such as low cost.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view of a foaming mold apparatus according to the present invention.
D-section

FIG. 2 is a plan view in which AA in FIG. 1 is a cross section;

FIG. 3 is a sectional view taken along line BB of FIG. 1;

FIG. 4 is a view showing another embodiment of the runner nesting.

FIG. 5 is a vertical sectional view of a current foaming mold apparatus, taken along line EE of FIG. 6;
With lines as cross-sections

FIG. 6 is a plan view showing a section taken along line CC of FIG. 5;

[Explanation of symbols]

 (1) Lower mold (2) Upper mold (3) Inside mold (5) Foundation as core material (6) Resin injection part (7) Runner insert

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Mikihiko Kimura 1-10-1 Shinsayama, Sayama City, Saitama Prefecture Honda Engineering Co., Ltd. (56) References JP-A-1-247117 (JP, A) (58) ) Field surveyed (Int. Cl. ⁶ , DB name) B29C 39/00-39/44 B29C 33/00-33/76

Claims (2)

(57) [Claims] A step of arranging a runner nest for allowing a mold resin injection portion to communicate with a desired portion of the mold in a mold; a step of closing the mold; and a step of forming a foamed resin from the resin injection portion. A step of injecting the liquid, introducing the resin liquid into a desired location in the mold by nesting a runner, and then foaming and filling the entire area in the mold from the location to form a molded product. Molding method for resin molded products. 2. The foamed resin molding according to claim 1, wherein the foamed resin molded article includes a core material, and the runner nest is provided integrally with the core material and disposed in a mold. Product molding method.