JP3195459B2 - Manufacturing method of 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 method for producing a foam molded article, and more particularly to a method for producing a foam molded article in which a core material and a skin are integrally formed of a foamed resin.

[0002]

2. Description of the Related Art As shown in FIGS. 8 and 9, a general foam molded article 70 such as an instrument panel of an automobile comprises a core material 71, a foamed resin 72 and a skin 73, and has a predetermined panel shape. It is formed in.

Conventionally, various methods have been proposed for producing such foamed molded articles. For example, (1) a so-called open mold system in which a foam material is set in a lower mold of a foam mold, a core material is set in an upper mold, and a foam material is poured into a cavity in an open state and the mold is closed to perform foam molding.
(2) A semi-closed foaming method in which a foam material is poured into a cavity while the upper mold is closed to a predetermined position, and a mold material is poured into the cavity with the upper skin and the core material set in the lower mold of the foam molding mold, respectively. Molding method (described in Japanese Patent Publication No. 3-75328), and (3) a core material is set on the lower mold of the foam molding mold with the upper skin and the upper mold, respectively, and a film gate is formed to communicate with the cavity in the mold-clamped state. A closed mold system (described in JP-B-63-28786) in which a foaming material is injected from the gate and foamed is formed.

However, the first method has a problem in that after the step of injecting the foaming material is completed, the operations of aligning and closing the upper and lower dies are required, and the time required to complete the operation is long. . For this reason, the foaming reaction of the foaming raw material progresses by the time of mold clamping, and the volume of the foaming raw material may increase and protrude from the cavity. The protruding foamed raw material wrapped around the back side of the core material and was attached to a molding die and caused product defects such as burrs. For this reason, a step of removing burrs from the molded product, a step of cleaning the mold, and the like are newly required, and there is a problem that work efficiency cannot be improved.

In the second method, the time required from the injection of the foaming raw material to the closing of the mold can be shortened. The foaming material starts a foaming reaction, and the foam layer is crushed by mold clamping, which may cause inconveniences such as cell roughness, underfill, and density unevenness.

Further, in the third method, since the foaming raw material needs to be passed through a narrow film gate, the foaming raw material is adjusted to a low viscosity and injected into the cavity at a high pressure. At this time, in order to prevent the low-viscosity foaming raw material from entering the backside of the core material, the core material is formed so as to extend to the rear of the film gate. However, after the product is released from the mold, the extended core portion must be crushed by a water jet or the like and removed from the product. For this reason, not only is new equipment required for performing the above-mentioned removal work necessary, but also the loss of the raw material relating to the removed core material increases, causing a cost increase. Further, in such a removing operation, there is a possibility that the cut surface of the core material becomes uneven, and the crushed core material adheres to the product and impairs the appearance of the product.

[0007]

DISCLOSURE OF THE INVENTION The present invention has been proposed to solve all the above-mentioned problems, and it is not necessary to extend the core material in a closed mold system, and to remove the core material. It is an object of the present invention to provide a method for efficiently obtaining a foam molded article having an excellent appearance without burrs or the like, which is unnecessary, and which has excellent workability.

[0008]

That is, the present invention provides:
Close the upper mold where the core material is arranged and the lower mold where the skin is arranged,
The outer periphery of the skin is sandwiched between the upper and lower mold parting surfaces except for the material injection port, the runner part and the gate part, and between the core material and the skin through the runner part and the gate part from the material injection port. In a method for producing a foam molded article in which a foaming material is injected and foamed integrally with a core material and a skin, a release film covering the upper mold parting surface corresponding to the material injection port, the runner portion and the gate portion is provided with a core material end portion. Fixed, the release film and the core material are arranged in the upper mold to form a raw material injection port, a runner portion and a gate portion between the inner surface of the release film and the inner surface of the skin peripheral portion. The method according to the present invention relates to a method for producing a foamed molded product, wherein a foamed product is formed by injecting a foam between a core material and a skin and integrally foaming the core material and the skin, and then the release film is removed from the foamed product.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a cross-sectional view showing an example of a foam mold for carrying out the method for producing a foam molded article of the present invention, FIG. 2 is a cross-sectional view showing a clamped state, FIG.
Is a cross-sectional view showing other portions, FIG. 5 is a perspective view showing an example of a temporarily fixed member, FIG. 6 is a cross-sectional view showing a molded article in a detached state, and FIG. 7 is a molding obtained by the manufacturing method of the present invention. It is a perspective view showing an example of an article.

FIGS. 1 and 2 show a foaming mold for carrying out the manufacturing method of the present invention. Reference numeral 10 is a foaming mold, 11
Is a lower mold, 12 is an upper mold, 13 is a hinge which constitutes the upper mold 12 so as to be openable and closable with respect to the lower mold 11, and 14 is a molded product cavity. The foam molding die 10 is provided with a raw material injection port 16 for a foam material at a part of a parting surface 15 of the lower mold 11 and the upper mold 12, and a raw material injection nozzle N is attached thereto, and a runner portion 17 is provided. And through the gate portion 18 to the cavity 14. In this embodiment, as shown by a chain line in FIG.
Reference numeral 8 denotes a so-called film gate formed in the molded product cavity 14 in a slit shape in the longitudinal direction on the back side of the product.

A skin 21 is provided on the cavity surface of the lower mold 11.
Is arranged. The skin 21 is formed slightly larger than the cavity surface, and when the lower mold 11 and the upper mold 12 are closed, the raw material injection port 1 serving as a flow path of the foamed raw material is formed.
6. The peripheral part 23 of the skin 21 is sandwiched by the parting surface 15 excluding the runner part 17 and the gate part 18.

A core member 22 is provided on the upper mold 12. Core material 2
Reference numeral 2 denotes a known hard resin, a metal plate or the like formed in a predetermined insert shape, and is attached to the cavity surface of the upper mold 12 by a pin member 24. It is not necessary to extend the length of the core 22 to the rear of the gate as in the conventional method, and it is preferable that the core 22 be formed in the shape of the core to be disposed in the product. As can be understood from FIGS. 3 and 4, a groove 27 is provided in an end surface portion of the core member 22. In this groove 27,
The release film 25 is temporarily fixed by the temporary fixing member 30.

The release film 25 is provided in the material injection port 1.
6, for covering the upper mold parting surface 15a constituting the runner portion 17 and the gate portion 18 to prevent the passing foam material from wrapping around the back side of the core material 22, and has a thickness of about 0.2 to 2 mm. Are preferred. Also, this release film 25
Raw material injection port 16 of a mold in which a film is previously arranged,
It is preferable that the size is slightly larger than the size covering the runner portion 17 and the gate portion 18. Thereby, when the mold is clamped, the mold portion is reliably covered with the release film, and the adhesion of the foaming material to the mold surface can be prevented.

In the upper mold 12, the release film 25
An appropriate number of suction holes 26 are provided in a portion corresponding to. The suction holes 26 are connected to an external vacuum device (not shown) or the like so that the release film 25 temporarily fixed to the end of the core material is suction-fixed to the upper parting surface 15a during molding. It has become.

The temporary fixing member 30 is made of a synthetic resin or the like having rubber elasticity. As is better understood from FIG. 5, the convex portion 31 and the end portion of the core member 22 provided continuously from the convex portion 31 are provided. And a protruding portion 32 having a shape protruding therefrom.
The convex portion 31 is formed in a shape that can be engaged with the groove 27 of the core material 22, and is engaged with the groove 27 of the core material 22 through an end of the release film 25 to release the mold. The film 25 is temporarily fixed to the end of the core material 22. FIG.
As will be understood from FIG.
Is fixed to the upper mold 12 so that the projection 32 projects toward the gate 18 of the mold.

The projecting portion 32 is for controlling the amount of the foaming material flowing into the cavity 14. In this embodiment, the projecting amount of the projecting portion 32 is
Are partially varied along the edge of Therefore,
As shown in FIG. 3, in the portion 32 a where the amount of protrusion of the protruding portion 32 is small, the flow path of the foaming material from the gate portion 18 to the cavity 14 is configured to be wide. FIG.
As shown in (2), in the portion 32b where the amount of protrusion is large, the distance from the skin 21 is short, and the flow path following the cavity 14 is narrow.

According to this structure, for example, when a molded article as shown in FIG. 7 is manufactured, the portion A where the distance from the gate portion 18 to the end of the cavity is long and the portion B where the distance is short are used in the resin flow direction. The amount is different. Therefore, in the portion A, as shown in FIG. 3, the amount of protrusion of the protrusion 32 is reduced so that the resin flows smoothly. On the other hand, in the portion B, the amount of protrusion of the protrusion 32 is increased as shown in FIG. 4 to restrict the flow of the resin. As a result, the flow rate of the resin corresponding to the cavity shape can be finely controlled, and the occurrence of voids, underfill, or rough cells in the molded product can be prevented.

At the time of molding, the skin 21 is attached to the lower mold 11.
The core material 22 on which the release film 25 is temporarily fixed is disposed on the upper mold 12. Then, the release film 25 is suction-fixed to the suction hole 26 of the upper die by a vacuum device (not shown), and the parting surface 15a of the upper die 12 is covered. Raw material injection nozzle N and the raw material injection port 1
The mold is clamped in the state where it is arranged at 6. Thereafter, as shown in FIG. 2, a foaming raw material U is injected from the raw material injection port 16 between the skin 21 and the core material 22.

The injected foaming raw material U is supplied to the runner section 1.
The cavity 14 is filled through the gate 7 and the gate 18, and is foamed integrally with the skin 21 and the core 22.
As described above, since the upper die 12 is covered with the release film 25 from the raw material injection port 16 to the end of the core material 22, the injected foamed raw material U goes around the back side of the core material 22. Can be prevented. Therefore, not only does the burr, etc., impair the appearance of the product,
Since the foaming raw material does not adhere to the molding die, it is possible to greatly reduce the labor required for operations such as cleaning the mold. The distance between the temporary fixing member 30 and the skin 21 in the gate portion 18 can be adjusted by changing the amount of protrusion of the protrusions 32a and 32b, and is injected according to the shape of the molded product cavity 14. By precisely controlling the amount of the foaming raw material U, a highly accurate product can be obtained.

After completion of the foaming reaction, the mold is opened and the molded article M is released as shown in FIG. Reference numeral 28 denotes a foam formed from the foaming raw material U. By removing the release film 25 and the temporary fixing member 30 adhered to the molded product M and cutting off the skin peripheral portion 23 along the shape of the molded product, a desired foam molded product is obtained. The removed temporary fixing member 30 can be collected and reused.

[0021]

As shown and described above, according to the method for manufacturing a foamed molded product of the present invention, in the closed mold system, the foamed material does not flow to the back side of the core material,
Burrs can be prevented and a highly accurate product can be obtained.
Therefore, there is no need to extend the core material, so that there is no loss of raw materials. In addition, there is no need for an operation or a device for removing the extended core portion from the product, so that the production efficiency can be increased and the production cost can be greatly reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an example of a foaming mold for carrying out a method for producing a foamed molded article of the present invention.

FIG. 2 is a cross-sectional view showing the mold clamping state.

FIG. 3 is a sectional view showing a main part thereof.

FIG. 4 is a cross-sectional view showing another part.

FIG. 5 is a perspective view showing an example of a temporary fixing member.

FIG. 6 is a cross-sectional view showing a mold release state of a molded product.

FIG. 7 is a perspective view showing an example of a molded product obtained by the manufacturing method of the present invention.

FIG. 8 is a perspective view showing an example of a general foam molded article.

FIG. 9 is a sectional view taken along line 9-9.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Foam molding die 11 Lower mold 12 Upper mold 15 Parting surface 16 Raw material injection port 17 Runner part 18 Gate part 21 Skin 22 Core material 25 Release film 27 Groove part 30 Temporary fixing member 31 Convex part 32 Projection part U Foam raw material

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI B29L 31:58 B29L 31:58 (56) References JP-A-56-115232 (JP, A) JP-A-1-152018 (JP JP-A-62-9920 (JP, A) JP-A-57-120421 (JP, A) JP-A-4-320808 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB B29C 39/10-39/12 B29C 39/22-39/44

Claims (2)

(57) [Claims] 1. An upper mold on which a core material is arranged and a lower mold on which a skin is arranged are closed, and the outer peripheral portion of the upper mold and the lower mold except for a raw material injection port, a runner part and a gate part are separated. And a foaming material is injected between the core material and the skin through the runner portion and the gate portion from the raw material injection port, and foamed integrally with the core material and the skin. Fixing the release film covering the upper parting surface corresponding to the runner portion and the gate portion to the end of the core material, and disposing the release film and the core material on the upper die to form the inner surface of the release film and the periphery of the skin. After forming a raw material injection port, a runner portion and a gate portion between the inner surfaces, a foamed material is injected between the core material and the skin from the raw material injection port, and foamed integrally with the core material and the skin to form a foamed product. Foaming characterized by removing the release film from the foamed product Method for producing a molded article. 2. The core member according to claim 1, wherein a temporary fixing member for temporarily fixing an end portion of the release film to an end portion of the core is detachably attached to the end of the core so that a part thereof protrudes from the end of the core. Attached to the release film and temporarily fixed, and by changing the protrusion amount of the temporary fixing member partially along the core material end to change the gap between the temporary fixing member and the skin,
A method for producing a foam molded article, characterized by controlling an injection amount of a foaming material injected between the skin and the core material.