JP3011872B2 - Foam molding substrate and method for producing foam molding - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a foam molding substrate and a method for producing a foam molded article.

[0002]

2. Description of the Related Art Foam molded products in which a base material and a foam are integrated are widely used for interior parts of automobiles and the like. In addition, the surface of the foam may be covered with a skin. As a method for producing the foam molded article, there is a closed injection method. In this closed injection method, as shown in FIG. 5, a base material 41 having a material injection opening 40 formed at a predetermined position is set on one mold surface 43 of a split mold 42, and a mold 4 is formed.
After closing the mold 2, the base material 41 and the other mold surface 45 of the molding die from the raw material injection nozzle N of the foam molding machine set in the nozzle insertion hole 44 of the molding die 42 through the raw material injection opening 40. This is a method in which a liquid foam molding raw material P is injected and foamed. At this time, if a skin 46 is arranged on the mold surface 45 facing the base material 41, a foam molded product in which the foam surface is covered with the skin is obtained.

[0003] In the case of an instrument panel or the like which is an example of an interior part of an automobile, a fixing means for fixing to a mating part may be provided on the back surface of the base material 41.
It is not preferable that the foam wraps around the back surface, and it is usual that the foam is formed so that the foam is not formed on the back surface of the base material 41 from the viewpoint of the mold design. For example, in the molding die 42 used for the closed injection method, when the nozzle N is installed in one of the molds on which the base material 41 is set, the tip of the nozzle N is flush with the mold surface 43. The material discharge port of the nozzle N is manufactured so as to accurately face the material injection opening 40 of the base material 41. Then, when the molding die 42 is closed, the back surface of the raw material injection opening 40 of the base material 41 closely contacts the front end surface of the nozzle N, and when the foaming forming raw material P is subsequently foamed, the raw material P is placed on the back surface of the base material 41. It was kept from protruding.

However, when the foam is molded as described above, the excess foaming gas that has not contributed to the formation of the foam is trapped in the foam in the mold, and the internal pressure in the foam increases. There is a problem of impairing the appearance of the foam molded article after demolding. In particular, in the production of a foam molded article having a base material 41 on one side of a foam and a skin 46 on the other side, such as an instrument panel, the above problem is caused by the difficulty in escaping excess gas in the foam. Was easy to occur.

[0005] Therefore, conventionally, tightening of a closed mold is performed by:
After the injection of the liquid foaming raw material, the molded product is loosened slightly before demolding to release the excess foaming gas outside the mold to lower the internal pressure. By releasing the tightening of the mold, the substrate 41 and the mold surface 4 on which the substrate is set are set.
3. A gap is generated between the base material 4 and the excess foaming gas.
The exhaust gas is rapidly discharged to the outside via the raw material injection opening 40. At this time, the excess foamed gas near the raw material injection opening 40 which is closest to the outside air through the gap is rapidly released. .

However, due to the rapid release of surplus gas from the raw material injection opening 40, the foam molding raw material P
Will be pulled out of the mold together with the gas. In addition, since the foam molding raw material P in the mold has not been completely cured at that time, the cells shrink, and the surface of the foam at the portion facing the raw material injection opening 40 is likely to sink.

[0007]

SUMMARY OF THE INVENTION The present invention has been proposed in order to solve the above-mentioned problem. In the closed injection method, a cell is preferably provided in a foam portion facing a material injection opening of a base material. It is an object of the present invention to provide a foam molding base material which hardly causes shrinkage or sink marks on the surface and a method for producing a foam molded article using the base material.

[0008]

SUMMARY OF THE INVENTION There are two inventions proposed herein, and the first invention relates to a foam molding base material having a vent hole around a raw material injection opening.

In a second aspect of the present invention, there is provided a raw material injection nozzle in which a foam molding base having a raw material injection opening formed therein is set in a molding die, and a front end surface is brought into contact with an outer peripheral surface of the raw material injection opening. The method for producing a foamed molded product in which a foamed material is integrated with the foaming molding base material by injecting and foaming a foaming molding material into a molding die through the raw material injection opening, Forming a gas vent hole around the raw material injection opening of the base material, and releasing a gas during foam molding from the gas vent hole to the outer surface of the foam molding base material. .

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a perspective view of a foam molding base material showing one embodiment of the first invention, FIG. 2 is a cross-sectional view thereof, FIG. 3 is a cross-sectional view of a foam molding die in one embodiment of the second invention, and FIG. It is sectional drawing which expands and shows a principal part.

As shown in FIGS. 1 and 2, the foam molding base material 10 of the present invention is mainly used for reinforcing or attaching a foam molded article, and is used for foam molding by a closed injection method. In this case, the foaming material is set in advance on the mold surface of the foaming mold, and is integrated with the foam to be formed by foaming of the foaming material injected into the mold. The base material 10 is made of an ordinary hard plastic such as an ABS resin, a polypropylene resin, or a polyphenylene oxide resin, or a fiber-reinforced plastic thereof, or a metal, and an opening 11 for material injection is provided at a predetermined position.

The raw material injection opening 11 is formed corresponding to the position of the nozzle insertion hole provided in the foaming mold to be set, and through the raw material injection opening 11 during foam molding. The foaming material is injected into the mold.

The base material 10 is provided with the material injection opening 1.
A plurality of gas vent holes 12, 12,... As described above, in the closed injection, the gas vent hole 12 is used to release the gas when the foaming material is injected and the excess foaming gas in the mold is released to the outer surface of the base material by slightly loosening the tightening of the mold. It is provided to function as a hole, and is provided so as to penetrate the base material 10 at a position surrounding the raw material injection opening 11.

The diameter of the gas vent hole 12 depends on the diameter of the raw material injection opening 11 and the amount of surplus gas to be escaped. However, in order to allow the surplus gas to escape gradually,
It is preferable that the diameter is smaller than the diameter of the raw material injection opening 11. In this embodiment, since the diameter of the material injection opening 11 is about 15 mm, the diameter of the gas vent hole 12 is about 2 mm.
And Further, the gas vent hole 12 is connected to the material injection opening 1.
By providing around the periphery of 1, surplus gas can be released from a wide range, and it is possible to prevent cell shrinkage and surface sink of the foam due to sudden generation of a local low-pressure portion in the foam.

The position of the gas vent hole 12 depends on the shape of the base material. However, if the gas vent hole 12 is too far from the raw material injection opening 11, the effect of preventing cell shrinkage and sink mark is reduced. That is, the gas venting hole 12 disperses and discharges the gas, which has been conventionally intensively discharged from the raw material injection opening 11, to the raw material injection opening 11 and the surrounding gas release holes 12. In order to prevent local cell shrinkage and sink marks on the surface of the foam, if the gas vent hole 12 is too far from the raw material injection opening 11, the raw material injection This is because gas is vented intensively from the opening 11.

If the gas vent hole 12 is too close to the raw material injection opening 11, the gas cannot be dispersed and gas vented, and the cell shrinkage and sink cannot be prevented. Therefore, in this embodiment, the gas vent holes 12 are scattered at equal intervals on a circumference approximately 70 mm away from the center of the raw material injection opening 11. The number thereof can be appropriately set according to the amount of gas to be degassed, and the number is eight in this example.

According to the base material 10, when producing a foamed molded article by the closed injection method, when releasing the tightness of the sealed mold to release the surplus gas to the outside of the mold, the surplus foaming gas is released. In addition to the raw material injection opening 11, the gas can escape from the gas vent hole 12 around the raw material injection opening 11. Therefore, since the surplus gas is dispersed and released, it is possible to prevent shrinkage of the cells of the foam and generation of sink marks caused by intensive outgassing from the raw material injection opening 11.

In this embodiment, the diameter of the raw material injection opening 11 is smaller than the diameter of the nozzle inserted into the nozzle insertion hole, and the outer peripheral surface surrounding the raw material injection opening 11 is made of a sealing material. The gas vent hole 12 is formed around the outer surface of the sticking surface 13 as the sticking surface 13. An appropriate sealing material made of an elastic material such as urethane slab is attached to the sealing material attaching surface 13,
The tip surface of the nozzle comes into contact. The sealing material prevents the generation of burrs due to the leakage of the foam molding raw material injected into the mold from the nozzle during the production of the foam molded product between the surface of the base material 10 around the raw material injection opening 11 and the mold surface. At the same time, the release of gas from the raw material injection opening 11 at the time of degassing is made smaller or more gradual to more efficiently prevent local cell shrinkage and sink marks of the foam. The tip surface of the nozzle comes into close contact with the sealing material during the production of a foam molded product.

Next, a method for producing a foam molded article according to the second invention using the foam molding base material according to the first invention will be described. FIG. 3 shows a foaming mold 20 used in the manufacturing method. This foaming mold 20 is a split mold used for a closed injection method, and includes a lower mold 21 and an upper mold 22.
Consists of Note that the mold 20 is not limited to the upper and lower two-piece mold as shown in the figure, and may be further divided into a plurality of molds.

A nozzle insertion hole 23 is provided at a predetermined position of the upper die 22. The nozzle insertion hole 23 is formed so as to penetrate to a die surface 24 of the upper die 22 on which the base material 10 is set. In addition, the nozzle N of the raw material injection device is inserted before or after closing the mold.

The upper die 22 is provided with the raw material injection opening 11 corresponding to the nozzle insertion hole 23 and the base material 1.
0 is set. In order to efficiently set the substrate 10 on the mold surface 24, the upper die 22 may be provided with a substrate fixing means such as a suction device or a pin.

A seal material sticking surface 13 is formed on the outer periphery of the raw material injection opening 11 of the base material 10, and a known seal material 14 having an annular shape is stuck thereto. The gas vent hole 12 is provided further around the outside of the attaching surface 13.

On the other hand, the other mold surface (the lower mold 21 in this embodiment)
A skin 26 is arranged on the mold surface 25. Next, the molding die 20 is closed, and the molding die 20 is clamped by a clamping means such as a clamp (not shown). Then, from the raw material injection nozzle N inserted into the nozzle insertion hole 23 of the upper die 22 before or after the closing of the mold, as shown in FIG. The material is injected into the mold through the material injection opening 11. At this time, as can be understood from FIG. 4, the material injection opening 11 of the base material 10 has a smaller diameter than the material injection nozzle N, and the sealing material sticking surface 13 formed on the outer peripheral surface thereof has a sealing material. Since the nozzle 14 is adhered, the nozzle tip end surface n is in close contact with the sealing member 14. Further, the sealing material 14 located on the outer periphery of the nozzle N is in close contact with the mold surface 24 of the upper mold. Therefore, the foam molding raw material P is injected into the molding die 20 without leaking from the raw material injection opening 11 between the base material 10 and the upper die surface 24.

The foam molding raw material P injected into the molding die 20
Fills the mold while generating a foaming gas by a foaming reaction, and integrates the resulting foam with the base material 10. Then, the upper mold 22 is loosened at an appropriate time until the hardening of the foam molding raw material P is completed, and excess foam gas is released into a gap formed between the upper mold 22 and the base material 10. And degassing. At this time, the material injection opening 1
1 is provided with a gas vent hole 12, so that the excess foaming gas can be dispersed and discharged from the gas vent hole 12, and the gas is intensively discharged from the raw material injection opening 11. Can be prevented.

Further, in this embodiment, the sealing material 14 is adhered around the raw material injection opening 11 of the base material 10 as described above, and the sealing material 14 is in close contact with the tip end surface n of the nozzle N. Therefore, even if the mold is released from being tightened for degassing, the release of surplus gas from the raw material injection opening 11 can be prevented or moderated. Therefore, the gas can be efficiently dispersed and released from the gas vent holes 12 around the raw material injection opening 11. afterwards,
If the molding die 20 is opened and the molded product is taken out, a foam molded product of good quality and appearance with less cell shrinkage and surface sink on the foam corresponding to the raw material injection opening of the base material can be obtained. Can be

[0026]

As shown and described above, according to the foam molding base material of the present invention, since the vent hole is provided around the raw material injection opening, the foam molding is performed using this base material. When the surplus gas is degassed in the production of the product, the gas can be released to the surface of the base material by dispersing the gas from the vent holes around the opening for injecting the raw material. Therefore, it is possible to suppress the gas from being intensively released from the opening for injecting the raw material, and it is possible to suppress the occurrence of the shrinkage of the cell and the sink on the surface in the foam portion facing the opening for injecting the raw material. Further, a sealing material adhering surface surrounding the raw material injecting opening is provided on the outer peripheral surface of the raw material injecting opening, and a gas vent hole is provided around the sealing material adhering surface. Due to the sealing material to be attached, rapid release of gas from the raw material injection opening can be further suppressed, and the gas can be more efficiently dispersed and released from the gas vent hole.

On the other hand, according to the method of manufacturing a foam molded article of the present invention using the foam molding substrate, excess foam gas generated during foam molding is removed by the gas formed around the raw material injection opening of the substrate. It can be dispersed through the holes and released to the substrate surface. Therefore, in the foam portion opposed to the material injection opening of the base material, which has been particularly susceptible to cell shrinkage and sink marks in the past, cell shrinkage and surface sink marks can be less likely to occur, and foam molding having good appearance and quality can be achieved. Goods can be obtained easily. Moreover, according to the method for producing a foamed molded product of the present invention, extra means and extra members are not required as compared with the conventional method, so that it is extremely economical.

Further, if a sealing material is adhered to the sealing material adhering surface surrounding the periphery of the raw material injection opening, the tip end surface of the nozzle and the sealing material adhere to each other at the time of molding, and the gas flows from the raw material injection opening during gas release. The rapid release of gas can be further suppressed, and the cell shrinkage and sink can be further reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view of a foam molding base material according to an embodiment of the first invention.

FIG. 2 is a sectional view thereof.

FIG. 3 is a sectional view of a foaming mold according to one embodiment of the second invention.

FIG. 4 is an enlarged cross-sectional view showing a main part thereof.

FIG. 5 is a sectional view of a molding die showing a method for producing a foam molded product by general closed injection.

[Explanation of symbols]

 Reference Signs List 10 base material 11 opening for material injection 12 gas vent hole 13 sealing material attaching surface 14 sealing material 20 foam mold 21 upper mold 22 lower mold N material injection nozzle n nozzle tip surface P foam molding material

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Toshiyasu Funato 3-1-36 Imaikecho, Anjo-shi, Aichi Pref. Innoac Corporation Anjo Office (56) References JP-A-49-96350 (JP, A) JP-A-62-97809 (JP, A) JP-A-3-81711 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B29C 39/10-39/12 B29C 39/22 -39/34 B32B 5/18-5/32

Claims (4)

(57) [Claims] 1. A foam molding base material having a gas vent hole around a raw material injection opening. 2. The method according to claim 1, further comprising a sealing material adhering surface surrounding the raw material injecting opening on an outer peripheral surface of the raw material injecting opening, and a gas vent hole formed around the sealing material adhering surface. A base material for foam molding, characterized in that: 3. A foam molding substrate having a material injection opening formed therein is set in a molding die, and a material injection nozzle having a front end surface in contact with an outer peripheral surface of the material injection opening is supplied to the material injection nozzle. A method for producing a foamed molded product in which a foamed material is integrated with the foaming molding base by injecting and foaming a foaming molding raw material into a molding die through an opening, wherein the foaming molding base material is injected. A method for producing a foam-molded article, characterized in that a gas vent hole is formed around an opening for use, and a gas during foam molding is released from the gas vent hole to the outer surface of a foam molding base material. 4. The sealing material according to claim 3, wherein a sealing material surrounding the raw material injection opening and closely contacting the tip end surface of the raw material injection nozzle is attached to an outer peripheral surface of the raw material injection opening of the foam molding base material. A method for producing a foam molded product, wherein a gas vent hole is formed around a sealing material attaching surface.