JPS5824248B2 - Method for manufacturing molded products containing protrusions - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing an integrally molded product in which an insert and a protruding rod of a bolt are inserted into a resin such as polyethylene, polypropylene, nylon, vinyl chloride, polyurethane, etc. The resin stock solution enters the threaded part of the
The object of the present invention is to provide a method that improves the drawbacks of the conventional method that requires a peeling operation after molding, and prevents the entry of resin stock solution.

Conventionally, urethane foam molded products into which bolts and the like are inserted have been used in many automobile interior parts such as armrests and console box lids. Generally, a method has been adopted in which a hole 2 is provided as a place for the bolt to escape, a bolt 5 with an insert 3 fixed by a seal plate 4 is inserted into the hole 2, and foaming liquid is injected and molded.

However, this method requires a flat insert 3 during molding.
If so, the reinforcing effect of the foam would be reduced because it would come into contact with the surface of the mold 1, so the insert 3 would have to be deformed as shown in the figure near the hole 2, which provides a place for escape.

However, if the insert is deformed in this way, processing costs will increase, and due to poor contact with the mold surface, the raw solution will flow into the hole 2, making it necessary to remove the threads after molding.

Normally, deburring work takes a lot of time, and especially when it comes to small items, this work becomes unnecessary.
This was not only troublesome, but also difficult.

The present invention aims to improve the drawbacks of the conventional molding method as described above, and involves fitting a bushing tube into a hole provided in a lower mold so as to protrude from the surface of the mold, and inserting the bushing through a sealing plate. Insert the protruding rod fixed to the bushing tube into the bushing tube, support the insert at the tip of the bushing tube, fix the position, and seal the outer surface of the seal plate with the inner surface of the bushing tube, then inject resin. It is characterized by obtaining an integrally molded product.

Hereinafter, specific embodiments of the manufacturing method of the present invention will be further explained in detail with reference to the accompanying drawings.

FIG. 2 illustrates one embodiment of the method of the present invention. Similar to FIG. 1, the lower mold 6 used for molding has cylindrical holes 7 at required positions to provide escape points for bolts, etc. It is provided.

Therefore, in the method of the present invention, the first step is to fit the cylindrical bushing tube 8 into the cylindrical hole 7 so that its tip protrudes from the surface of the lower mold 6.

In this case, the height of the protrusion of the bushing tube 8 determines the position of the insert in the final molded product, and an appropriate height is set in consideration of the wall thickness of the molded product.

Next, insert the insert 9 into the sealing plate 10 while holding it diagonally upward.
A protrusion insert 12 with a protrusion rod, e.g., a bolt 11 attached to the bottom thereof, is fitted into the cylindrical bushing tube 8, and the insert 9 is supported by the tip 13 of the bushing tube to fix the position. At this time, the sealing plate 10 is not bonded to the inner wall of the bushing tube 8, but is brought into close contact with the inner wall of the bushing tube 8 to seal the inside of the bushing tube and prevent the resin liquid 14' from entering.

Note that the bushing tube 8 and the sealing plate 10 as described above usually require dimensional accuracy because they need to be sealed with each other, but considering the raw material with good fluidity, the bushing tube 8 is made of synthetic material such as polypropylene or nylon. Seal plate 10 using resin
On the other hand, since the sealing material 10 has another function of connecting the insert and the bolt, its material depends on the insert and the bolt.
Select from metal materials, hard synthetic resin materials, and other appropriate materials.

For example, when the insert 9, the seal plate 10, and the bolt 11 are all made of the same hard synthetic resin material, these members can also be made by integral molding.

After the above conditions are set, an upper mold (not shown) is placed over the mold, and a foaming solution 14' of polyurethane, vinyl chloride, polyethylene, etc. is injected to obtain a molded product 14 of a predetermined shape.This foam molding method is known in the art. It's a method.

In the case of this foam molding method, a known mold release agent is applied to the inner surfaces of the upper and lower molds as usual, and also to the outer peripheral surface of the bushing tube 8 protruding from the lower mold 6 and the outer peripheral surface of the seal plate 10. As a matter of course, the above-mentioned mold release agent is applied.

Therefore, after the molding is completed, the molded product 14 is easily separated from the lower mold 6 and the bushing tube 8, and the bushing tube 8 remains in the hole 7 of the lower mold 6.

In the molded product 14 obtained by the above molding method, for example, as shown in Fig. 3, the insert is fixed on the inside and fully contributes to reinforcing the molded product, and the threaded part does not have any undiluted solution, making it easy to deburr. It does not require

As described above, according to the method of the present invention, a bushing tube is used and the sealing plate is brought into close contact with the inner wall of the bushing tube in a sealed state to prevent resin liquid from entering. It is easy to select the appropriate insert position and fix the insert inside, which is not only effective in increasing the reinforcement of the molded product, but also prevents resin liquid from entering the threaded part and improves molding. It has the feature that there is no need for later deburring work, making it easy to work with even small products.Furthermore, since the insert is fixed inside, there is no need to deform the insert as with conventional methods, resulting in cost savings. This is a manufacturing method that is truly useful and has practical value.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram showing one aspect of the conventional manufacturing method, and is a cross-sectional view of a state in which a bolt is inserted into a mold, and Figure 2 is a cross-sectional view of a state in which a bolt is inserted into a mold. FIG. 3 is a cross-sectional view of a molded article obtained by the method of the present invention. 6... Lower mold, 7... Hole, 8...
... Bush tube, 9 ... Insert, 10 ...
... Seal plate, 11 ... Protruding rod (bolt)
, 12... Protrusion insert, 13... Bush tube tip, 14... Molded product, 14'...
・Foamed resin stock solution.

Claims (1)

[Claims] 1. A bushing tube 8 is fitted into a hole 7 provided in a lower mold 6 so as to protrude from the surface of the mold 6, and then an insert 9 and a projection rod 11 are connected by a seal plate 10. Insert the insert 12 into the bush tube 8, hold the insert 9 at the tip 13 of the bush tube 8, fix the position, and bring the outer surface of the seal plate 10 into sealing contact with the inner wall of the bush tube 8, and then A method for manufacturing a molded product including a protrusion insert, characterized in that an integrally molded product 14 is manufactured by injecting a resin stock solution 14'. 2. The method for manufacturing a molded product including a protrusion insert according to claim 1, wherein the bushing tube 8 is made of a synthetic resin material. 3. The method for producing a molded article containing a protrusion insert according to claim 1 or 2, wherein the resin stock solution 14' is a urethane foaming solution.