JPS60147311A - Integral foam forming method - Google Patents

Abstract

PURPOSE:To prevent a burr from producing even if a small gap between an upper mold and a core material by bonding the burr to the mold surface surrounded by a sealing material and utilizing it as the sealing material in the molding thereafter. CONSTITUTION:A mold releasing agent is not coated on an upper mold 1, coated only on the back surface of a core material 6 before mounting in the mold 1, foamable urethane elastomer solution 7 is then filled in a lower mold 2, the mold 1 is then closed to form foam, and removed from the mold. Then, a burr 8 remains bonded to the mold 1, thereby performing the role of a sealing material in case of the following molding. Thus, even if a gap exists between the upper mold and the core material, urethane is prevented from flowing merely by fixing the burr formed in the initial molding, thereby causing the same effect as the zero butting method. In the following molding, stable molding can be continued merely by coating the mold releasing agent on the back surface of the core material, and the exchanging time of the sealing material can be shortened.

Description

[Detailed Description of the Invention] [Industrial Application Field] Is the present invention a core material (insert)? : This is a method for molding foamed plastic products, and more specifically, it relates to a method for preventing molding during molding.

(Prior art) For example, foamed plastic molded bodies are used as safety bats around and on the upper surface of automobile instrument panels.To obtain such products, a core material is placed in a mold, for example an upper mold. After fixing, foamable plastic is injected into the cavity, the mold is closed, and the plastic is foamed.

However, depending on the shape of the molded product, since a core material with an opening is used, there is a problem in that plastic flows to the back side of the core material, causing cracks.

This occurs because during foaming, plastic enters through the gap created between the core material and the center part of the upper mold to make it easier to attach the core material, and the resulting molded product is Plastic flakes adhere to the back of the material in spots, which not only makes it unsightly, but also makes it difficult to attach the molded product to the desired location. At this time, this paris becomes a nuisance, which causes various problems such as the need for a step to remove the paris.

Conventionally, as a means to prevent the occurrence of cracks on the back side of the product, a zero alignment method has been used to minimize the gap between the upper mold and the core material, and urethane rubber or silicone has been used on the surface of the upper mold that contacts the core material. Elastic seams such as rubber.

However, the following problems occurred with this method:

In other words, in the zero alignment method, the gap between the core material and the upper mold is extremely small, so the core material cannot be set properly.Furthermore, since the core material and the shed are rigid bodies, it is actually impossible to completely reduce the gap to zero. It is impossible to eliminate Paris.

In the conventional method of using a sealing material, a hard sealing material with an angular cross section made of urethane rubber or the like is pressed with strong force and embedded in the upper mold, and the core material is made by elastically deforming to conform to the shape of the sealing surface of the mold. This is to prevent plastic from entering the back side. However, this method also has the following drawbacks: ■ When setting the core material into the upper mold, force is required to press and deform the sealing material, and it is impossible to embed it in an upper mold with a particularly uneven shape. The material has high hardness and does not conform to the shape of the mold, resulting in insufficient sealing performance.■ If the sealing material is repeatedly deformed, it will not be able to return to its shape, so it is often necessary to use a new one. ■If the upper mold is sprayed with a mold release agent containing an organic solvent, the sealing material will be corroded and will need to be replaced in a short period of time, resulting in an extremely large amount of man-hours. There is.

[Purpose of the invention]

In view of the above-mentioned problems, the present invention aims to provide an integral foam molding method that can prevent the occurrence of cracks even if there is some gap between the upper mold and the core material.

[Structure of the invention]

The present inventor focused on the fact that the bar itself seals the gap between the upper mold and the core material, and if it is actively formed and left in the upper mold, then subsequent molding will be possible. They came up with the idea that it could be used as a sealing material, and completed the present invention.

That is, in the integral foam molding method of the present invention, in order to seal the gap created between the periphery of the opening of one core material and the mold surface when the core material is attached to the upper mold, a seal is applied to the relevant part of the mold surface in advance. After placing the core material, the mold surface surrounded by the sealant is injected with foamable plastic without applying KFi mold release agent, cured, released, and molded onto the mold surface surrounded by the sealant. It is characterized in that it is used as a sealing material in the subsequent molding process.

Once the sealant is formed according to the present invention, the originally used sealant is no longer necessary. □The sealing material formed in the new nine can withstand use for a certain period of time depending on the selection of the mold release agent. This kind of sealing material itself has gaps inside, so it easily deforms when the core material is pressed against it.
Since it adheres closely to the core material, a complete seal is achieved.

The foamable plastic used for molding is not particularly limited, but hair-forming polyurethane, which has elasticity and adhesive properties, is particularly effective.

〆〆!　m　＃＋１　＋　”　’ Hereinafter, the present invention will be explained based on examples.

Fig. 1 is a sectional view showing one embodiment of the present invention, and is a molded product having an opening in the center, such as a molded product for an automobile register, or a molded product with left and right sides independent of each other. The upper mold 2 represents the lower mold assembly, and the lower mold 2 has an opening 3 in the center. This is provided. This molding! To perform molding using a mold, rotate the upper mold 1 using a shaft (not shown) as a fulcrum,
After the mold is opened, a skin 4 such as a polyvinyl chloride sheet is set on the mold surface of the lower mold 2. After that, upper mold 1
A cushioning material 5 such as sponge is pasted on the outside of the opening 3, and then a core material 6 molded into a predetermined shape from an iron plate or fiber-reinforced As resin is attached to the upper mold 1.

Next, apply a mold release agent to the upper mold 1. Apply the mold release agent to the back side of the core material 6 before attaching it to the upper mold gate, and then inject the foamable urethane elastomer liquid 7 into the lower mold 2. When the upper mold 1 is closed and the foam molding is completed, the 1 inch of the foot is opened and the mold is removed. The adhesive remains and can serve as a sealing material during subsequent molding.The cushioning material 5 is removed as it is no longer needed.

In this manner, even if the seal is damaged during repeated molding, new urethane elastomer is supplied, so it can be effectively used as a sealing material for a long period of time.

Even if it were to be replaced, it would require almost no man-hours as it would be sufficient to repeat the process described above.

〔Effect of the invention〕

As described above, according to the present invention, even if there is a gap between the upper mold and the core material, by simply fixing the gap formed in the first molding, the inflow of urethane is prevented, and the same effect as the zero alignment method is produced. In the subsequent molding process, stable molding can be continued simply by applying a mold release agent to the back side of the core material, and the sealing material can be replaced in a short time, which greatly improves productivity.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an embodiment of the present invention, and FIG. 2 is a sectional view of an upper mold to which a sealing material is attached. 1... Upper mold 2... Lower mold 3... Opening 4... Outer skin 5... Cushioning material 6... Core material 7... Urethane elastomer liquid 8... Paris patent applicant Toyota Motor Corporation

Claims (1)

[Claims] When the core material is attached to the mold surface, a sealing material is placed in advance on the relevant part of the mold surface so that the space created between the periphery of the core material opening and the mold surface can be sealed. After installation, foamable plastic is injected into the mold surface surrounded by the sealant without applying a mold release agent, cured and released, and Paris is attached to the mold surface surrounded by the sealant, which is used for subsequent molding. An integral foam molding method characterized by its use as a sealing material. □