JPH0929763A - Foam molding base material and manufacture of foamed molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a foam molding base material in which shrink mark is scarcely generated on the surface of a foam opposed to the raw material casting opening of the base material in a closed casting method and a method for manufacturing the foamed molding using the base material. SOLUTION: The method for manufacturing a foamed molding comprises the steps of setting a foam molding base material having a gas bleeding hole 12 at the periphery of a raw material casting opening 11 in a mold, casting foam molding raw material P in the mold via the opening 11 from a raw material casting nozzle N brought into contact with the end face at the outer peripheral surface of the opening 11 to foam it, thereby releasing gas at the time of foam molding from the hole 12 at the outer surface of the base material in the case of integrating the generated foam with the base material.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a foam-molding base material and a method for producing a foam-molded article.

[0002]

2. Description of the Related Art Foam molded articles in which a base material and a foam are integrated are widely used for automobile interior parts and the like. The surface of the foam may be covered with a skin. As a method for manufacturing 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 raw material injection opening 40 formed at a predetermined position is set on one mold surface 43 of a split mold 42, and the mold 4 is formed.
After closing 2, 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, the base material 41 and the other die surface 45 of the molding die. This is a method in which a liquid foam molding raw material P is injected in between to foam. At this time, if a skin 46 is placed on the mold surface 45 facing the base material 41, a foam-molded article in which the surface of the foam is covered with the skin can be obtained.

In an instrument panel or the like, which is an example of an interior part of an automobile, there is a case where a fixing means for fixing a counterpart component is provided on the back surface of the base material 41.
It is not preferable for the foam to wrap around on the back surface, and it has always been manufactured in consideration of the mold design so that the foam is not formed on the back surface of the base material 41. For example, in the molding die 42 used in the closed pouring method, when the nozzle N is installed in one of the molds in which the base material 41 is set, the tip of the nozzle N is flush with the mold surface 43. In addition, the raw material discharge port of the nozzle N is manufactured so as to accurately face the raw 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 is in close contact with the tip surface of the nozzle N, and when the foam molding raw material P is subsequently foamed, the raw material P is applied to the back surface of the base material 41. It was designed not to stick out.

However, when the foam is molded as described above, the surplus 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 that the appearance of the foamed molded product after demolding is impaired. In particular, in the production of a foam-molded article having a base material 41 on one surface of the foam and a skin 46 on the other surface such as an instrument panel, it is difficult for excess gas in the foam to escape, so the above problem Was likely to occur.

Therefore, conventionally, the tightening of a closed mold is
After injecting the liquid foaming raw material, the molded product is slightly loosened before it is released from the mold to allow the excess foaming gas to escape to the outside of the mold to lower the internal pressure. By releasing the tightening of the molding die, the base material 41 and the mold surface 4 on which the base material is set
3 creates a gap between the base material 4 and the excess foaming gas.
No. 1 is rapidly released to the outside through the raw material injection opening 40. At this time, excess foaming gas near the raw material injection opening 40 that is closest to the outside air is rapidly released through the gap. .

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. Moreover, since the foam molding raw material P in the mold was not completely cured at that time, shrinkage of the cells occurred, and sink marks were liable to occur on the surface of the foam facing the raw material injection opening 40.

[0007]

SUMMARY OF THE INVENTION The present invention has been proposed to solve the above-mentioned problems, and in the closed pouring method, a cell is formed especially in the foam portion facing the raw material pouring opening of the base material. An object of the present invention is to provide a base material for foam molding which is less likely to cause shrinkage and sink marks on the surface and a method for producing a foam molded article using the base material.

[0008]

There are two inventions proposed here, and the first invention relates to a foaming base material having a gas vent hole around a raw material injection opening.

A second aspect of the invention is a raw material injection nozzle in which a foam molding substrate having a raw material injection opening is set in a molding die and a tip end surface is brought into contact with the outer peripheral surface of the raw material injection opening. In the method for producing a foam-molded article, wherein the foam-forming material is integrated with the foam-molding base material by injecting the foam-molding raw material into the mold through the raw material-injecting opening to foam, A method for producing a foam-molded article, characterized in that a gas vent hole is formed around a raw material injection opening of a base material for foaming, and gas at the time of foam molding is allowed to escape from the gas vent hole to the outer surface of the base material for foam molding. .

[0010]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in detail below with reference to the accompanying drawings. 1 is a perspective view of a foam molding base material showing an embodiment of the first invention, FIG. 2 is a sectional view thereof, FIG. 3 is a sectional view of a foam molding die in an 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. At this time, it is set on the mold surface of the foam molding die in advance, and is integrated with the foam to be formed by foaming the foam molding raw material injected into the mold. The base material 10 is made of ordinary hard plastic such as ABS resin, polypropylene resin, polyphenylene oxide resin, or fiber reinforced plastics thereof, or metal, and a raw material injection opening 11 is provided at a predetermined position thereof.

The raw material injection opening 11 is formed in correspondence with the position of the nozzle insertion hole provided in the foam molding die to be set. During foam molding, the raw material injection opening 11 is inserted through the raw material injection opening 11. The foam molding material is injected into the mold.

The base material 10 is the opening 1 for injecting the raw material.
1 has a plurality of gas vent holes 12, 12, ... As described above, the gas vent hole 12 is a gas vent for closed foaming when the foaming raw material is injected and then the mold clamping is loosened slightly to allow the surplus foaming gas in the mold to escape to the outer surface of the base material. It functions 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 varies depending on the diameter of the raw material injection opening 11 and the amount of surplus gas to be released, but in order to gradually release the surplus gas,
The diameter is preferably 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 used as the raw material injection opening 1
By providing it around 1, the excess gas can be escaped from a wide range, and it is possible to prevent the cell shrinkage of the foam and the sink mark on the surface due to the rapid occurrence of a local low pressure portion in the foam.

The position of the gas vent hole 12 varies depending on the shape of the base material, but if it is too far from the raw material injection opening 11, the cell shrinkage and sink preventive effect will be reduced. That is, the gas vent holes 12 disperse the gas, which has been conventionally intensively released from the raw material injection opening 11, into the raw material injection opening 11 and the gas vent holes 12 around the raw material injection opening 11 to release the gas. Thus, in order to prevent local cell shrinkage and sink marks on the surface of the foam, when the gas vent hole 12 is too far from the raw material injection opening 11, the raw material injection opening 11 is provided near the raw material injection opening 11 as in the conventional case. This is because the gas is intensively vented from the opening 11.

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

According to the base material 10, when a foamed molded article is manufactured by the closed injection method, when the tightening of the closed mold for releasing the excess gas is released, the excess foamed gas is removed. Not only the raw material injection opening 11 but also the gas vent hole 12 around the raw material injection opening 11 can escape. Therefore, since the surplus gas is dispersed and released, it is possible to prevent the cells of the foam from shrinking or sinking due to the concentrated gas escape from the raw material injection opening 11.

In this embodiment, the diameter of the raw material injection opening 11 is made 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 sealed with a sealing material. The attachment surface 13 is formed, and the degassing holes 12 are formed around the outside of the sealing material attachment surface 13. An appropriate sealing material made of an elastic material such as urethane slab is stuck to the sealing material sticking surface 13,
The tip surface of the nozzle comes into contact. The sealing material prevents the generation of burrs due to leakage of the foaming raw material injected into the mold from the nozzle during the production of the foamed molded product to the surface of the base material 10 around the raw material injection opening 11 and between the mold surfaces. At the same time, the amount of gas released from the raw material injection opening 11 at the time of degassing is further reduced or slowed down to more effectively prevent local cell shrinkage and sink marks of the foam. The tip end surface of the nozzle is brought into close contact with the sealing material when the foamed molded product is manufactured.

Next, a method for producing the foam-molded article of the second invention using the foam-molding base material of the first invention will be described. FIG. 3 shows a foaming mold 20 used in the manufacturing method. This foam molding die 20 is a split type used in the closed pouring method, and includes a lower die 21 and an upper die 22.
Consists of The molding die 20 is not limited to the two upper and lower halves as shown in the drawing, and may be further divided into a plurality of split dies.

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

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

A sealant attaching surface 13 is formed on the outer periphery of the raw material injection opening 11 of the base material 10, and a known sealant 14 having an annular shape is adhered to the sealant attaching surface 13. A gas vent hole 12 is provided further outside the attachment surface 13.

On the other hand, the other mold surface (in this embodiment, the lower mold 21
A skin 26 is disposed on the mold surface 25. Then, 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 mold 22 before or after the closing mold, as shown in FIG. It is injected into the mold through the material injection opening 11. At that time, as understood from FIG. 4, the raw material injection opening 11 of the base material 10 has a smaller diameter than the raw material injection nozzle N, and the seal material is adhered to the seal material sticking surface 13 formed on the outer peripheral surface thereof. Since the nozzle 14 is attached, the nozzle tip surface n is in close contact with the sealing material 14. Further, the sealing material 14 located on the outer circumference 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 poured into the molding die 20 without leaking from the raw material pouring opening 11 between the base material 10 and the upper mold surface 24.

Foam molding raw material P injected into the molding die 20.
Fills the inside of the mold while generating foaming gas by the 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 curing of the foam molding raw material P is completed, and excess foaming gas is allowed to escape to the gap between the upper mold 22 and the base material 10 generated thereby. , Degas. At that time, the raw material injection opening 1
Since a gas vent hole 12 is provided around 1, the excess foaming gas can be dispersed and released from the gas vent hole 12, and the gas is intensively released from the raw material injection opening 11. Can be prevented.

Further, in this embodiment, as described above, the sealing material 14 is attached around the raw material injection opening 11 of the base material 10, and the sealing material 14 is in close contact with the tip surface n of the nozzle N. Therefore, even if the mold tightening is released to release the gas, the release of the excess 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 hole 12 around the raw material injection opening 11. afterwards,
When the molding die 20 is opened and the molded product is taken out, a foamed molded product having good quality and good appearance, in which there is little cell shrinkage and surface sink mark in the foamed body corresponding to the raw material injection opening, is obtained. To be

[0026]

As shown and described above, according to the foam molding base material of the present invention, since there is a gas vent hole around the raw material injection opening, the foam molding base material is used for foam molding. At the time of degassing the surplus gas at the time of manufacturing the product, the gas can be dispersed from the gas vent hole around the raw material injection opening to release the gas to the surface of the base material. Therefore, it is possible to suppress the intensive release of gas from the raw material injection opening, and it is possible to prevent cell shrinkage or surface sink from occurring in the foam portion facing the raw material injection opening. Further, in the case where a sealing material attaching 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 in the periphery thereof, the sealing material attaching surface is attached to the sealing material attaching surface. The sealing material attached can further suppress the rapid release of gas from the raw material injection opening, and can more efficiently disperse the gas and release it from the gas vent hole.

On the other hand, according to the method for producing a foam-molded article of the present invention using the foam-molding base material, the surplus foaming gas generated during foam-molding is formed by the gas formed around the raw material injection opening of the base material. It can be dispersed through the holes and discharged to the surface of the substrate. Therefore, it is possible to prevent cell shrinkage or surface sinkage from occurring in the foam portion facing the raw material injection opening of the base material, which has been particularly prone to cell shrinkage or sinkage, and has a good appearance and quality. Goods can be obtained easily. Moreover, according to the method for producing a foam-molded article of the present invention, no extra means or extra members are required as compared with the conventional method, which is extremely economical.

Further, if a sealing material is adhered to the sealing material adhering surface surrounding the raw material injecting opening, the nozzle tip end face and the sealing material are brought into close contact with each other at the time of molding, so that the gas from the raw material injecting opening at the time of gas release Rapid release of gas can be further suppressed, and shrinkage and sink marks of the cell can be further reduced.

[Brief description of drawings]

FIG. 1 is a perspective view of a foam molding base material showing 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 an embodiment of the second invention.

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

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

[Explanation of symbols]

 10 Base Material 11 Raw Material Injection Opening 12 Gas Venting Hole 13 Sealing Material Adhering Surface 14 Sealing Material 20 Foam Mold 21 Upper Mold 22 Lower Mold N Raw Material Injection Nozzle n Nozzle Tip Surface P Foaming Raw Material

Claims (4)

[Claims] 1. A foam molding base material having a gas vent hole around a raw material injection opening. 2. The seal material sticking surface surrounding the raw material injection opening is formed on the outer peripheral surface of the raw material injection opening, and a gas vent hole is formed around the seal material sticking surface. A base material for foam molding which is characterized in that 3. A raw material injection nozzle in which a foam molding substrate having a raw material injection opening is set in a molding die, and a tip end surface is brought into contact with the outer peripheral surface of the raw material injection opening. In a method for producing a foam-molded article, which comprises integrating a foam produced by injecting a foam-molding raw material into a molding die through an opening to foam the resulting foam-molding base material. A method for producing a foam-molded article, characterized in that a gas vent hole is formed around the opening for use, and gas at the time of foam molding is allowed to escape to the outer surface of the foam-molding base material from the gas vent hole. 4. The seal material according to claim 3, wherein a sealing material is attached to the outer peripheral surface of the raw material injection opening of the foam molding base material so as to surround the raw material injection opening and closely adhere to the tip surface of the raw material injection nozzle. A method for producing a foam-molded product, characterized in that a gas vent hole is formed around the surface on which the sealing material is attached.