JPS62130808A - Manufacture of expansion molded parts - Google Patents

Abstract

PURPOSE:To prevent the surface of an expansion molded part from being stained by some leaked-out expanded material and consequently manufacture the high- quality expansion molded part by a structure wherein a foam well which is open to outside through a constriction communicating with the interior of a skin body is protrudedly formed on the hollow skin body. CONSTITUTION:At a corner on the bottom face of a hollow skin body 19, an expanded foam well 17 is protrudedly formed integral with a skin body 19 through a tubular constriction 16, which communicates with the interior of the skin body 19. Expansion molding is performed in the interior of the skin body 19 by pouring expandable raw material through a pouring port 23. The air in the skin body 19 and CO2 and the like developed by gas blowing reaction ascend within the skin body, pass through the constriction 16 and the expanded foam well 17 and finally escape outside. At the same time, the expansion molding operation proceeds so that some portion of the foam pushes the gaseous matter from behind and leaks out through the constriction 16 into the well 17. When the expansion molding completes, a molded part 27 is removed from a mold. In addition, the foam well 17, in which leaked-out expanded material is trapped, is cut off from the skin body at the root of the constriction 16.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a method for manufacturing a foamed molded product, and more specifically to a product such as a headrest, which is an automobile interior part, in which a hollow skin is formed. In the manufacturing process of products in which a foaming solution is injected into the body and the epidermis is filled with foam, the foam may be damaged due to air or other gases remaining in the hollow epidermis, and the foam may leak from within the epidermis. This invention relates to a method for producing foam molded products that multifacetedly eliminates product stains caused by unexpected leakage.

(Prior Art) As a manufacturing method for foam molded products such as automobile headrests, for example, as described in JP-A-55-158944, blow molding is used to form a hollow skin body. , a manufacturing method in which a hole for inserting an air blowing pipe is integrally formed, and the foaming stock solution is injected into a hollow skin body using the hole as an injection port, or JP-A-60-8
As described in Publication No. 018, the foaming stock solution is injected into the epidermis through the injection port formed integrally with the outside of the bag-like outer skin body, and the injection port is closed to inject the foaming stock solution. A method of manufacturing a foam molded product is known in which the protruding injection port is removed at the final stage after foaming is completed.

(Problems to be Solved by the Invention) However, in the invention described in JP-A No. 55-158944, a portion of the foaming stock solution leaks from the injection port, causing damage to the surface of the epidermis. Foam leakage material that adheres to the product will impair the appearance of the product, and if there is a lot of leakage of the foaming stock solution, air pockets will occur within the hollow skin, especially at the corners.

Furthermore, in the above-mentioned invention described in JP-A-60-8018, after the foaming stock solution is injected into the bag-like outer skin, in order to close the injection port protruding from the surface of the outer skin, the bag-like outer skin is The internal pressure inside the bag-like shell increases due to the mixture of the air present in the body and the gas generated by the reaction of the foaming stock solution.As a result, even after the reaction of the foaming stock solution is completed, there is a hollow space inside the bag-like shell. There are still problems that need to be solved, such as hollow parts, which tend to remain in the corner parts of the bag-like outer shell, causing the finished molded product to lose its shape.

The present invention provides a method for producing this type of foam molded product, in which gas containing air is reliably discharged from the hollow skin, while leakage of foam material from the skin is allowed to some extent, while preventing the gas from reaching the product surface. The main purpose is to prevent adhesion and staining caused by foam materials.

(Means for Solving the Problems) In order to achieve this object, the present invention has the following configuration. That is, the method for producing a foamed molded product according to the present invention includes forming an expanded foam reservoir on the outside of the synthetic resin hollow skin through a constricted part so that the inside and outside of the skin communicate with each other. After completion of the foaming reaction of the foaming stock solution formed into a protruding shape and injected into the hollow skin body, the foam reservoir section that captures the leaked foam is separated and removed from the narrowed section.

(Function) When the foaming stock solution is injected into the hollow skin body, the gas generated by the reaction of the foaming stock solution and the air present inside the hollow skin body mix, and as the internal pressure of the hollow skin body increases, these gas bodies It passes through a constriction and an expanded foam reservoir leading to the outside of the body. In addition, as the gas is released, some of the foam is prevented from leaking from the skin at the narrowed part, but some of the leaked foam is caught in the reservoir and remains, preventing further leakage. Foam spillage is effectively prevented.

(Example) Next, a specific example of the present invention will be described with reference to the drawings, taking an automobile headrest as an example.

Fig. 1 is a perspective view of a hollow skin body for a headrest with supporting legs seen from the bottom side, and Fig. 2 is a partially cutaway perspective view of a molding device in the process of molding the hollow skin body for a headrest shown in Fig. 1. be.

At the bottom of the hollow skin body for a headrest made of synthetic resin shown in Fig. 1, a pair of support legs (7) (7) are located on the parting line (A) formed approximately in the center. The expanded foam body protrudes and is located on the same parting line (A) near the bottom corner of the hollow skin body α Samurai through a cylindrical narrowed part αe that communicates with the inside of the hollow skin body OI. A reservoir portion (1η) is formed to protrude integrally with the skin body OI.

Next, a method of manufacturing the hollow skin body with supporting legs having the above structure will be explained with reference to FIG. 2. A pair of half-split molds <1) (1
) are provided with fitting grooves (2) (2) of the supporting legs (7) (7) and flat plate-shaped blocks into which a plate-shaped block (described later) fits between the grooves (2) (2), respectively. A depression (3) is formed. 1 which is in the open state at a predetermined interval.
A cylindrical parison (5) made of synthetic resin, such as polyvinyl chloride resin or ABS resin, extruded from the extrusion die (4) is lowered between the pair of half-split molds (1) (1). I'll come. On the other hand, a plate OI is arranged below the pair of half-split molds (1) (1) when they are in a chain state,
A pair of supporters αυ fixed to the upper surface of the plate 01
Using the hole provided in the center of (11), attach a pair of supporting legs (
7) Core body (7) assembled with reinforcing material (6) between
8), the core body (8) is removably installed on the upper surface of the plate QI by fitting the tip portions of the supporting legs (7) (7). In addition, a plate-shaped block α force is arranged between the pair of supports 0υaυ on the top surface of the plate 00, and a small diameter block is located on the outside of one of the supports 01) on the top surface of the plate 00. Pipe 0 →, stepped air blowing pipe with a large diameter pipe α on the base side is plate 0
1 is inserted from below so that it can come out and go out. On the lower opposing wall of the pair of half-split molds (IXI) is a small diameter pipe α of the stepped air blowing pipe αυ.
What are the narrow grooves (A) and thick grooves suitable for fitting the pipe and large diameter pipe 03, respectively? A continuous groove of υ is formed.

Above, stepped air blowing pipe αυ, plate block 0
The above-mentioned members αQQ2 (8) on the core body fixing jig (to) equipped with the core body (8) are extruded from the extrusion die (4), and the bottom opening ( 9), set in a state that wrapped each of these members α (6) and (8), and heated to 40 to 60°C.
In the pair of half-split molds (1) (1), the plate block Q2 is inserted into the flat plate recess (3) (3) of the mold (1), and the stepped air blowing pipe 051 is inserted into the mold (1). In the continuous groove formed from the narrow groove (1) and the thick groove ■υ, one of the core bodies (8)
The pair of supporting legs (7) (7) are fitted into the fitting grooves (2) (2), and the mold is closed while holding a part of the parison (5).

Then, from the stepped air blowing pipe O5 into the mold cavity, more precisely into the parison (5).
Inject 1 kg/cA of compressed air into the parison (5
) is expanded and crimped onto the cavity surface of the mold to complete the blow molding of the hollow skin body.

After blow molding, the half-split mold (1) (1) is opened and the hollow skin body for the headrest is made into a collapsed mold, and a pair of supporting legs (1) are attached from the support (l) αη on the plate aO. 7)
(7) is removed.

Hollow skin body α with supporting legs for headrest thus obtained
Due to the presence of the flat plate block (6) between the pair of support legs (7) (7) on the parting line formed in the center of the field, an injection port (c) is formed relatively. , and due to the presence of a continuous groove between a narrow groove (1) and a thick groove C1) formed in the mold (1) near the corner of the hollow skin body Ql, located on the outside of one of the supporting legs (7). Relatively formed cylindrical narrowing part O
An expanded foam interspace aη is integrally formed in a protruding manner via e.

The protruding location of the foam gap part aη, which communicates with the skin body α through the cylindrical narrowing part αG, is the corner of the hollow skin KQI, which is a place where air is relatively likely to accumulate inside the hollow skin body α. It is preferable that the protrusion be placed in the area or in a position relatively close to this location, and the number of protrusions may be plural if necessary. Further, the size of the through hole of the narrowed narrowed portion Qf19 is set to a diameter that prevents the foaming stock solution from leaking through the through hole, specifically, a diameter of 4 to 6H.

In addition, the expanded foam part αη also serves as a discharge port for collecting air and other gases and releasing them to the outside in the final stage of the foaming reaction of the foaming stock solution.

In addition, in the molding stage of the hollow skin body a shown in FIG.
A pair of sheet-like fabrics is arranged hanging down between the outside of the cylindrical parison (5), that is, between the parison (5) and the mold (1), and the closed mold is used to form a hollow surface whose surface is covered with the fabric. It is also possible to mold the skin body.

Next, the molded hollow skin body with supporting legs for a headrest is placed in an openable/closable mold for foam molding (C) (C), and the slit-shaped injection port (C) is forcibly opened and expanded. do,
A foaming raw material such as polyurethane resin is injected through the injection port, and the mold is then clamped to seal the injection port (c) (see FIG. 4).

Under the above circumstances, foam molding is performed within the skin body α9, but at this time, the air inherent in the skin body α9 and gases such as CO2 generated by the foaming reaction of the foaming raw material,
As the internal pressure of the hollow epidermis rises, it rises within the hollow epidermis and moves toward the cylindrical narrowing part ad, forming the narrowing part (113
The foam material is then released to the outside through the expanded foam gap αη, and at the same time, the foam molding operation proceeds without any restrictions, and while pushing the gas body, a part of the foam Although it is extremely small, it leaks through the narrowing part αQ into the reservoir part αη.

When the foam molding was completed, the foam molded product) was removed from the mold (a), and some of the leaked foam material from the root of the injection port (c) with the skin body OI and inside the hollow skin body was captured. The foam stiffness part (17) is connected to its skin body and the narrowing part (lυ
It is cut and removed at the base.

In order to more reliably prevent leakage of the foam to the outside, that is, to more reliably capture the foam at the foam elastic part 071, as shown in FIG. A second cylindrical constriction part 0 for releasing only the gas is connected to the open end part of the foam elastic part (17), thereby preventing leakage of the foam to the outside. The blocking effect is further enhanced. In order to form this second cylindrical narrowed part (16), a second groove is formed, and a stepped air blowing pipe 0υ which is retractably disposed on the plate (10) described in FIG. Instead, an air blowing pipe (not shown) consisting only of a stepless small diameter pipe section with an air outlet opening in the horizontal direction at approximately the center of the small diameter pipe.
By using this continuous groove and the effect of the small diameter pipe, the second cylindrical narrowed portion a6 can be formed simultaneously when the hollow skin body is formed.

The above explanation has focused on headrests as a foam molded product, but it can also be used for automobile interior parts, such as armrests, seats, and other furniture in general, with cores inserted inside hollow skin bodies. Foaming can be carried out on the entire product including the body.

(Effects of the Invention) The present invention has a hollow skin body formed with a protruding foam elastic portion that is open to the outside of the body through a constriction portion that communicates with the inside of the skin body. When performing foam molding by injecting a foaming stock solution into the hollow skin, the air present inside the skin or the gas generated during the foaming reaction process of the foaming material is absorbed into the narrowed areas and the foam as the internal pressure of the hollow skin increases. It can be released outside the body naturally through the body parts, and the foaming reaction proceeds without any restrictions, so there is no retention of air or other gases in the hollow skin, and foaming is prevented. In the final stage of the reaction, the gas is collected at the foam edges and released to the outside, which effectively eliminates the harmful effects of gas remaining in the product, which can cause problems in maintaining the quality of foam molded products and other aspects. can be removed,
In addition, even if undesirable foam material leaks from the hollow skin, the leaked foam material is captured by the expanded foam elastic part and can be prevented from leaking further to the outside. It is possible to prevent the surface of the molded product from staining due to some of the leaked foam, and it is possible to produce high-quality foam molded products in many ways.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a hollow skin body for a headrest with supporting legs for carrying out the present invention, viewed from the bottom side, and FIG. 2 is a molding device in the process of molding the hollow skin body for a headrest shown in FIG. 1. Partially cutaway perspective view, Figure 3 is @A- of Figure 1.
An enlarged cross-sectional view taken along line A; FIG. 4 is a central vertical cross-sectional view of the hollow skin body housed in the mold and formed into a foam molded product;
FIG. 5 is a view corresponding to FIG. 3 showing another embodiment, and FIG. 6 is a perspective view of a part of the half-split mold for molding the hollow skin body shown in FIG. 5. In the figure, αQai represents a narrowed portion, α represents an expanded foam stiffness portion, and OI represents a hollow skin body. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6

Claims (4)

[Claims] (1) In a form that communicates between the inside and outside of the synthetic resin hollow epidermis, an expanded foam reservoir is formed in a protruding manner through a constriction on the outside of the epidermis, and then injected into the hollow epidermis. After the foaming reaction of the foaming stock solution is completed, the foam reservoir portion that has captured the leaked foam is separated and removed from the narrowed portion. (2) The method for manufacturing a foam molded product according to claim 1, wherein a second narrowing portion is provided on the open end side of the foam reservoir. (3) The method for manufacturing a foam molded product according to claim 1 or 2, wherein the foam reservoir is formed near a corner of the hollow skin body. (4) The foam reservoir portion and the narrowing portion are formed by a part of the resin material constituting the skin body during molding of the hollow skin body. A method for producing a foamed molded product as described in Section 1.