JP2756840B2 - Method for manufacturing foam molded article with embedded insert - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for manufacturing a foam molded product in which an insert having an opening is partially embedded.

(Prior Art) Conventionally, there is a so-called molding method as a method for producing a foam molded product having a predetermined shape in which a product mounting or reinforcing insert is embedded. In the molding method, an insert is installed on the mold surface of a split mold, and a liquid foaming material such as a polyurethane foam material is injected into the mold cavity and foamed, thereby forming a foam having a cavity shape. To manufacture goods.

(Problems to be Solved by the Invention) However, in the above-mentioned manufacturing method, air existing in the cavity or gas (gas) generated at the time of foaming is apt to accumulate in the cavity. Air pockets (hollow portions) or underfill were generated, and defective products were likely to occur.

In particular, in the case of a large-sized foam molded product such as an instrument panel pad of an automobile, since the distance from the mold dividing surface serving as a gas discharging portion to the center of the mold cavity is long, gas easily accumulates in the cavity, Further, since free movement of gas is hindered by an insert such as an iron plate, the gas is more likely to stay in the cavity, and air pockets and the like are more likely to be generated.

In addition, the insert is often provided with an opening for attaching other parts to the molded product after foam molding or for reducing the weight, in which case the liquid foaming material is provided on the back surface of the opening of the insert. There is also a problem that leaks easily form unnecessary burrs.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a method of manufacturing a foam molded article capable of preventing the occurrence of air pockets and underfill due to gas accumulation and preventing the occurrence of burrs at the opening of the insert.

(Means for Solving the Problems) The gist of the present invention to achieve the above object is to provide a partially open insert on a mold surface, and to inject and foam a liquid foaming raw material into the mold cavity. In the method of manufacturing a foam molded article embedded with the insert, in the mold surface predetermined portion where the opening of the insert will be located,
A gas absorber made of a hard permeable porous body is buried so that the surface is exposed, and an insert whose opening is closed with a permeable body made of a soft or semi-rigid foam is installed on the mold surface, and the A method for producing a foam molded article in which an insert is embedded, characterized in that a foaming material is foamed in a mold cavity.

(Operation) As the liquid foaming raw material injected into the cavity foams and fills the cavity, gas such as air left in the cavity or gas generated by foaming is repelled to the vicinity of the opening of the insert. Then, the air escapes to the upper surface of the insert through the air-permeable body closing the opening. When the internal pressure in the mold increases due to further foaming, the gas is compressed and held so as to be absorbed in the gas absorbent body made of a hard gas-permeable porous body exposed on the mold surface. This prevents gas from stagnating in the foam molded article. Further, the foaming raw material filling the cavity is prevented from leaking from the opening to the back surface of the insert by the air-permeable body made of a soft or semi-rigid foam closing the opening of the insert. Thereafter, when the foamed molded product is taken out of the molding die, a foamed molded product free of air pockets and underfill and having no burrs made of a leaked material at the insert opening can be obtained. On the other hand, the gas that has been compressed and absorbed in the absorber by releasing the mold is released to the atmosphere.

(Example) Hereinafter, an example of the present invention will be described.

FIG. 1 and FIG. 2 are cross-sectional views of a molding die during production of a foam molded product in which an insert is embedded according to an embodiment of the present invention.

The molding die 10 is a split die separated into an upper die 12 and a lower die 14, and has a cavity 20 having a predetermined shape defined by the mold surfaces 16, 18. Gas absorbers 22 and 23 are buried in the upper mold surface 16 so as to protrude from the mold surface 16 at predetermined portions where openings of the insert described later are to be located. The gas absorbers 22 and 23 are made of a hard permeable porous material, such as a ceramic filter,
The size is set to a size capable of absorbing gas in the cavity that causes air pockets and the like, and the optimum size differs depending on the shape of the cavity, the composition of the liquid foaming raw material, and the like.

The mold surface 16 of the upper mold 12 and the mold surface 18 of the lower mold 14 are provided with an insert 24 and a skin 25 described below.

The insert 24 is used for reinforcing or mounting a product that also serves as reinforcement, and is usually made of metal or plastic, and has openings 26 and 28 formed at predetermined portions.
The openings 26 and 28 are formed to reduce the weight of the insert or to attach another component to a molded product after foam molding.

The insert 24 thus formed is provided with the openings 26, 2
After 6 is closed with the permeable members 30 and 31 made of a soft or semi-rigid foam, the openings 26 and 28 are fitted with the permeable porous members 22 and 23 of the upper die surface 16. , Is accurately mounted on the mold surface 16. As the breathable bodies 30 and 31 made of a soft or semi-rigid foam, a polyurethane foam having a thickness of 2 to 3 mm is preferable.

In order to close the openings 26 and 28 of the insert with the permeable members 30 and 31, a double-sided adhesive tape is attached to the periphery of the openings 26 and 28, and the peripheral portions of the permeable members 30 and 31 are attached to the double-sided adhesive tape. Is easy to glue. Also, insert 24 into upper mold surface 16
When the insert 24 is made of metal, it is convenient to embed a magnet in the mold surface 16 and use the magnetic force of the magnet.

On the other hand, the skin 25 is made of plastic leather or opaque fabric, and is formed into a predetermined shape by sewing or the like.

The insert 24 and the skin 25 formed in this manner are molded 10
After the apparatus is set on the mold surface, a liquid foaming raw material made of a polyurethane foam raw material or the like is poured onto the skin 25, and the reaction of the liquid foaming raw material 32 is started in the mold cavity 20 as shown in FIG.

Due to the progress of the reaction, the liquid foaming raw material 32 foams and fills the cavity 20, and drives air existing in the cavity and gas generated by the foaming upward.
Most of the gas displaced upwards is
The gas which escapes from the mold from 33 is left behind, but is passed to the gap between the upper surface of the insert and the upper mold surface through the permeable members 30 and 31 closing the openings 26 and 28 of the insert 24.
When the foaming further proceeds and the internal pressure in the cavity is increased by the released gas, the gas is compressed and absorbed into the air-permeable porous bodies 22 and 23 on the mold surface. This prevents gas from stagnating in the foamed raw material. At this time, the foamed raw material filling the cavity is hardened without leaking from the openings 26, 28 to the back surface of the insert because the openings 26, 28 of the insert are closed with a gas-permeable body, and the insert is hardened. It becomes a foam molded product having a buried cavity shape.

The desired product can be obtained by removing the foam molded product in which the insert is embedded from the mold.

FIG. 3 is a cross-sectional view of the foam molded product 34 in which the insert thus obtained is embedded. The foam molding 34
Has no air pockets or underfill due to gas accumulation, and has no burrs made of leaked materials on the back surfaces of the inserts 26 and 28. Reference numeral 36 in the drawing denotes a foam formed from a liquid foaming raw material.

(Effect) Since the present invention has the above-described configuration, a foam molded product in which the insert is embedded can be obtained without air pockets and underfill, and furthermore, burrs at the opening of the insert can be prevented. It was.

[Brief description of the drawings]

1 and 2 are cross-sectional views of a molding die during production according to an embodiment of the present invention, and FIG. 3 is a cross-sectional view of a foam molded product in which the obtained insert is embedded. 10: molding die, 12: upper die, 14: lower die, 16, 18: die face, 20: die cavity, 22, 23: breathable porous body, 24: insert, 26, 28: opening, 30, 31: breathable body made of soft or semi-rigid foam, 32: liquid foam raw material

Claims (1)

(57) [Claims] 1. A method for manufacturing a foam molded article having an embedded insert by installing a partially open insert on a mold surface, injecting a liquid foaming material into the mold cavity and foaming the insert. A gas absorber made of a hard permeable porous body is buried in a predetermined portion of the mold surface where the opening is to be located so that the surface is exposed, and the opening is opened by a permeable body made of a soft or semi-rigid foam. A method for producing a foamed product in which an insert is embedded, wherein an insert having a closed portion is provided on a mold surface thereof, and a liquid foaming material is foamed in a mold cavity.