JP2008080523A - Method for producing foamed resin molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive method for producing a foamed resin molding while avoiding the appearance quality lowering of a skin material and the defective molding of resin foam when the foamed resin molding with the resin foam and the skin material integrated is produced. <P>SOLUTION: In the method for producing the foamed resin molding 10, after the skin material 18 is set between a pair of openable/closable molds 20a and 20b, a molten resin 22 added with a foaming agent is injected/supplied into a molding part 30, and after the passage of prescribed time, by opening the molds 20a and 20b by a prescribed distance, the molten resin 22 is expanded to integrate the skin material 18 and the resin foam 16. An injection port 36 for injecting/supplying the molten resin 22 into the molding part 30 is formed in a non-product part molding part 34. The size C2 between both molds of the non-product part molding part 34 is set to be larger than the size C1 between both molds of a product part molding part 32. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for producing a resin foam molded article in which a skin material and a resin foam are laminated and integrated.

  Conventionally, after a skin material is set between a pair of molds, a molten resin containing a foaming agent is injected and supplied into a molding portion formed between the pair of molds. A method for producing a resin foam molded body in which a molten resin is foamed by lowering the internal pressure of the molded part by opening a predetermined amount of the mold and the skin material and the resin foam are integrated at the same time as molding is known. (See Patent Document 1). Since the resin foam molded body manufactured by this technique is lightweight and highly rigid, it can be applied to automotive interior materials such as instrument panels, seat backs, partition boards, console boxes, door trims and the like.

JP 2001-334540 A

  In the above-described conventional technology, the size of the dimension between the molds of the molding part (distance between the inner surfaces of the molds) at the time of injecting the molten resin is important for the following reasons.

  That is, when the dimension between both molds of the molded part is made as small as possible, it is possible to prevent volatilization (so-called gas escape) of the foaming agent contained in the molten resin. Thereby, it becomes possible to prevent the foaming failure of the molten resin, and it becomes possible to prevent the molding failure of the resin foam and the deterioration of the appearance quality of the resin foam.

  However, if the dimension between the molds of the molded part is too small, various problems will occur due to the injection pressure of the molten resin when the molten resin is injected into the molded part. For example, the injection pressure of the molten resin may cause wrinkles or the like formed on the surface of the skin material to sink or cause wrinkles or the like on the surface of the skin material.

  Therefore, in order to solve these problems, it is conceivable to laminate a barrier material on the back surface of the skin material. By laminating the barrier material on the back surface of the skin material, it is possible to protect the skin material from damage caused by the injection pressure of the molten resin.

  However, a skin material in which a barrier material is laminated on the back surface is considerably more expensive than a normal skin material. Therefore, there is a manufacturing method of a resin foam molded body that does not lead to an increase in cost while avoiding a molding defect of the resin foam and a decrease in the appearance quality of the skin material in order to increase the manufacturing cost of the resin foam molded body. It was strongly desired.

  In addition, it is also conceivable to provide an injection port in the non-product part as a means for preventing deterioration in the appearance quality of the resin foam molded article. In that case, in order not to affect the appearance quality, the area of the non-product part must be increased, and the area of the skin material must be increased accordingly. However, since the skin material is more expensive than the resin material, the overall manufacturing cost is increased.

  The present invention has been made in view of the circumstances as described above, and its purpose is to improve the appearance quality of the skin material when producing a resin foam molded body in which the resin foam and the skin material are integrated. An object of the present invention is to provide a method for producing a resin foam molded article that can be produced at a low cost while avoiding a decrease and a molding defect of the resin foam.

Means for solving the problems are the following inventions.
1st invention is the manufacturing method of the resin foam molding by which skin material and resin foam were integrated, Comprising: The process of setting the said skin material between a pair of molds which can be opened and closed, A step of injecting and supplying a molten resin to which a foaming agent is added to a molding part for molding the resin foam molded body formed between the two molds in a closed state or a semi-closed state of the mold; and The molten resin injected into the molding part is opened by opening the pair of molds by a predetermined distance after the predetermined time has elapsed after the molten resin is filled in the entire area of the molding part or the pair of molds are completely closed. Foaming and integrating the skin material and the resin foam, and molding the resin foam molded body, the resin foam molded body is a product part that is a part used as a product, and a product It ’s an unused part A molded part formed between the pair of molds corresponding to the resin foam molded product, and a product part molded part that is an area for molding the product part; A non-product part molding part that is a region for molding the non-product part, and an injection port for injecting molten resin into the molding part is provided in the non-product part molding part The dimension between the two molds of the non-product part molding part when the molten resin is supplied is set to be larger than the dimension between the two molds of the product part molding part. It is a manufacturing method of a foaming molding.

  According to the first invention, the injection port for injecting the molten resin into the molded part is provided in the non-product part molded part. That is, the molding part formed between the pair of molds is used as a product part molding part for molding a part (product part) used as a product of the resin foam molding and a product among the resin foam moldings. It is divided into a non-product part molding part for molding a portion (non-product part) that cannot be formed. Out of these two, the injection port for injecting the molten resin into the molding part is provided in the non-product part molding part. Thereby, the injection pressure at the time of injecting the molten resin does not directly act on the skin material of the product part, and it is avoided that the appearance quality of the product part is affected.

  Further, according to the first invention, the dimension between both molds of the non-product part molding part is set larger than the dimension between both molds of the product part molding part. Thereby, since the dimension between both molds becomes small in the product part molding part, it is possible to prevent volatilization of the foaming agent (so-called gas escape), and in the non-product part molding part, between the two molds. Since the dimensions are large, it is possible to prevent the injection pressure of the molten resin from becoming excessive. As a result, while avoiding poor foaming of the molten resin due to outgassing, it is possible to avoid problems such as depressions formed on the skin material near the injection port of the molten resin due to the injection pressure of the molten resin. Is possible.

  2nd invention is a manufacturing method of the resin foam molding of the said 1st invention, Comprising: When the thickness of the said skin | cover material is set to T (mm), the dimension between the both molds of the said product part molding part is the following. It is a manufacturing method of the resin foaming molding characterized by being set within T + 5mm.

  According to the second aspect of the invention, the dimension between both molds of the product part molding part is set to an optimum range within the thickness T + 5 mm of the skin material. That is, the dimension between both molds of the product part molding part is set in a range sufficient to prevent volatilization (so-called gas escape) of the foaming agent contained in the molten resin, thereby improving the product quality.

  A third invention is a method for producing a resin foam molded article according to the first or second invention, wherein a dimension between both molds of the product part molding part is C1 (mm), and the non-product part molding part is When the dimension between both molds is C2 (mm), it is set to C2 = C1 + α (α is 0.5 mm or more and 2.0 mm or less). is there.

  According to the third invention, the dimension C2 between the two molds of the non-product part molding part is the optimum range C1 + α (α is 0.5 mm or more and 2.0 mm or less) between the two molds of the product part molding part. Set to That is, the dimension C2 between the two molds of the non-product part molding part is larger than the dimension C1 between the two molds of the product part molding part, and a defect such as a depression formed on the skin material is avoided. By setting the range to a sufficient range, the area of the non-product part can be reduced, the yield of the skin material and the resin material can be improved, and the manufacturing cost can be suppressed.

  According to the present invention, when manufacturing a resin foam molded body in which a resin foam and a skin material are integrated, a reduction in the appearance quality of the skin material and a molding defect of the resin foam are avoided, and at a low cost. It becomes possible to provide the manufacturing method of the resin foam molding which can be manufactured.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a perspective view showing an appearance of a resin foam molded body 10. FIG. 2 is a top view of the resin foam molded body 10. FIG. 3 is a cross-sectional view taken along line AA of the resin foam molded body 10 shown in FIG. The resin foam molded body 10 integrally includes a product portion 12 that is a portion used as a product after completion and a non-product portion 14 that is a portion not used as a product.

As shown in FIGS. 1-3, the resin foaming molded object 10 is formed in the substantially plate shape as a whole, and is formed in the shape where the center part was dented. The central concave portion is a non-product part 14, and a pair of product parts 12 are arranged on both sides of the non-product part 14.
In the present embodiment, the product portion 12 is an upper base that constitutes the upper edge portion of the vehicle door trim. On the other hand, the non-product part 14 is a part that is separated from the product part 12 and discarded or reused.
The resin foam molded body 10 is formed by laminating and integrating a skin material 18 made of woven fabric or nonwoven fabric on the surface of a resin foam 16 formed by foaming a foaming agent added to a thermoplastic resin such as polypropylene. (See FIG. 3).

  FIG. 5 shows a pair of molds 20a, 20b for molding the resin foam molded body 10 and an injection device 40 for supplying a molten resin to a molding part 30 formed between the molds 20a, 20b, and an injection nozzle 42. The injection port 36 is shown. The molding part 30 formed between the pair of molds 20a and 20b is for molding the product part molding part 32, which is an area for molding the product part 12 of the resin foam molded body 10, and the non-product part 14. And a non-product part molding part 34 which is a region of In other words, the molding part 30 can be divided into two regions, “product part molding part 32” and “non-product part molding part 34”. In FIG. 5, in order to distinguish these two regions, a broken line is shown between the product part molding part 32 and the non-product part molding part 34.

  Further, the injection port 36 for supplying the molten resin 22 into the molding part 30 is provided in the non-product part molding part 34, and the resin supply provided penetrating through the inside of the fixed mold 20a. It is connected to the tip of an injection nozzle 42 of an injection device 40 installed outside via a passage 38. Thereby, the molten resin 22 can be injected and supplied from the injection device 40 into the molding part 30 with a predetermined injection pressure.

FIG. 8 is an enlarged cross-sectional view of the molding part 30 formed between the pair of molds 20a and 20b. As shown in this figure, the dimension C1 (mm) between both molds of the product part molding part 32 is as shown in FIG. The dimension C2 (mm) between both molds of the non-product part molding part 34 is set to be smaller. The dimensions C1 and C2 between the two molds here are the distances between the opposed surfaces of the molds 20a and 20b of the product part molding part 32 and the non-product part molding part 34 when the molten resin 22 is injected and supplied. The size is set so as to satisfy the following formulas.
C1 ≦ T + 5 (T is the thickness (mm) of the skin material 18)... Formula (1)
C2 = C1 + α (α is 0.5 mm or more and 2.0 mm or less) Formula (2)

  By satisfying the above formula (1), the dimension C1 between the two molds of the product part molding portion 32 is set to an optimum range within the thickness T + 5 mm of the skin material 18. That is, when the dimension C1 between the two molds of the product part molding part 32 is too large, the volatilization of the blowing agent contained in the molten resin 22 (so-called outgassing) is sufficiently performed in the molten resin injection supply process. It cannot be prevented. In this case, problems such as chipping of the resin foam 16 due to poor foaming and unevenness on the skin material 18 side may occur. Therefore, it is preferable that the dimension C1 between the two molds of the product part molding part 32 is as small as possible. However, when the thickness of the skin material 18 is T (mm), the dimension C1 between the two molds is T + 5 mm. By setting the value within the range, it is possible to sufficiently avoid such a phenomenon.

  When the above formula (2) is satisfied, the dimension C2 between both molds of the non-product part molding part 34 is C1 + α (α is 0.5 mm or more and 2.0 mm or less between the two molds of the product part molding part 32. ). In this case, the dimension C2 between both molds of the non-product part molding part 34 is set to be larger than the dimension C1 between both molds of the product part molding part 32. The injection pressure when the molten resin 22 is supplied by injection can be lowered. As a result, the skin material 18 near the injection port 36 of the molten resin 22 is damaged by the injection pressure of the molten resin 22, so that the wrinkles formed on the skin material 18 are depressed, or the skin material 18 is wrinkled. It is possible to prevent the occurrence of problems such as Therefore, the area of the non-product part can be reduced, and the yield of the skin material and the resin material can be improved.

  The method of manufacturing a resin foam molded body according to the present embodiment includes a step of setting a skin material between a pair of molds that can be opened and closed (skin material setting step), and a pair of molds in a semi-closed state. A step of injecting and supplying a molten resin to which a foaming agent has been added into a molded part formed between the steps (a molten resin injection supply step), and a pair of dies after a predetermined time has passed since the pair of dies were closed Is opened by a predetermined distance to foam the molten resin injected into the molding part and integrate the skin material and the resin foam (resin foam molding process). Hereinafter, these three steps will be described with reference to FIGS.

(Skin material setting process)
As shown in FIG. 4, in the skin material setting step, the skin material 18 is set between a pair of molds 20a and 20b that can be opened and closed.
The pair of molds 20a and 20b is configured to be opened and closed by a driving source such as a cylinder, and is closed when the movable mold 20b approaches the fixed mold 20a, and the fixed mold 20a is closed. The movable mold 20b is opened by moving away from 20a. The distance between the pair of molds 20a and 20b can be arbitrarily adjusted.

As the skin material 18 set between the pair of molds 20a, 20b, a known skin material can be used. For example, a woven fabric, a nonwoven fabric, a knitted fabric, a film or a sheet formed of a thermoplastic resin or a thermoplastic elastomer can be used. Furthermore, a composite skin material in which a cushion layer made of polyurethane, rubber, thermoplastic elastomer or the like is laminated on these skin materials can also be used.
In this embodiment, the skin material 18 is set on the inner surface of the movable mold 20b. However, in order to set the skin material 18 between the pair of molds 20a and 20b, either one of the molds is used. The skin material 18 may be fixed to the inner surfaces of 20a and 20b using a jig or the like.

(Molten resin injection supply process)
As shown in FIG. 5, in the molten resin injection and supply step, the molten resin 22 to which a foaming agent is added is injected and supplied into a molding portion 30 formed between a pair of molds 20a and 20b in a semi-closed state. To do. Thereafter, the pair of molds 20 a and 20 b are completely closed, and the molten resin 22 is filled in the entire area of the molded part 30.

  There is no particular limitation on the type of molten resin 22 that is injected into the molding part 30 and supplied, and thermoplastic resins that are generally used for automobile interior parts and the like can be used. For example, polypropylene resins, polyethylene resins, polystyrene resins, acrylic resins such as polymethyl methacrylate, polyamide resins such as ABS and nylon 6, polyester resins, polycarbonate resins, polyphenylene ether resins and the like can be used. .

  The kind of foaming agent added to the molten resin 22 is not particularly limited, and any foaming agent known in the art as a thermoplastic synthetic resin foaming agent can be used. Specifically, for example, inorganic foaming agents such as sodium bicarbonate, ammonium bicarbonate, ammonium carbonate, nitroso compounds such as N, N′-dinitrosopentamethylenetetramine, azodicarbonamide, azobisisobutyronitrile, etc. Azo compounds, benzenesulfonyl hydrazide, toluenesulfonyl hydrazide, sulfonyl hydrazides such as diphenylsulfone-3,3′-disulfonyl hydrazide, and blowing agents such as p-toluenesulfonyl semicarbazide can be used. Furthermore, you may add a salicylic acid, urea, and the foaming adjuvant containing these as needed.

  Then, by providing the injection port 36 for injecting and supplying the molten resin 22 in the non-product part molding portion 34, a wrinkle is depressed near the injection port 36 of the skin material 18 due to the injection pressure, or the surface is wrinkled. Even if a malfunction occurs, the product part 12 is not affected and the appearance quality of the product part 12 does not deteriorate. Further, by making the dimension C2 between both molds of the non-product part molding part 34 larger than the dimension C1 between both molds of the product part molding part 32, the area of the non-product part can be reduced, and the skin material The yield of the resin material can be improved.

(Resin foam molding process)
As shown in FIGS. 6 and 7, in the resin foam molding process, after a predetermined time has elapsed since the pair of molds 20a and 20b are closed, the pair of molds 20a and 20b is opened by a predetermined distance, thereby forming a molded part. The molten resin 22 injected into 30 is foamed to integrate the skin material 18 and the resin foam 16.

  When the pair of molds 20a and 20b are closed, the molten resin 22 injected into the molded part 30 spreads into the molded part 30, and the press pressure by the pair of molds 20a and 20b against the molten resin 22 Acts (see FIG. 6). The reaction of the foaming agent added to the molten resin 22 is promoted by the heat of the molten resin 22. Then, after a predetermined time has elapsed, the pair of molds 20a and 20b are opened by a predetermined distance, whereby the internal pressure of the molding part 30 is reduced, and the molten resin 22 is expanded and expanded to form the resin foam 16 (FIG. 7). At this time, the resin foam 16 is pressure-bonded to the skin material 18, whereby the resin foam molded body 10 in which the skin material 18 is integrated on the surface of the resin foam 16 is formed.

  After the resin foam molded body 10 is cooled, the resin foam molded body 10 can be taken out from between the pair of molds 20a and 20b. Thereafter, the product part 12 and the non-product part 14 of the resin foam molded body 10 are separated from each other, thereby completing a pair of left and right upper bases constituting the upper end part of the door trim of the vehicle door. In addition, what is necessary is just to use a well-known press cutting machine etc. in order to isolate | separate the product part 12 and the non-product part 14. FIG.

  In this resin foam molding process, the pressing pressure of the molten resin 22 by the pair of molds 20a and 20b and the moving distance of the mold 20b when the pair of molds 20a and 20b are closed or opened are set appropriately. can do.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention, and further, within the scope not departing from the gist of the invention other than the following. Various modifications can be made.
(1) In the above embodiment, an example in which the product portion of the resin foam molded body is the upper base of the door trim is shown, but the present invention is not limited to such an embodiment. The present invention can be applied to other automobile interior materials such as an instrument panel, a seat back board, a partition board, a console box, an entire door trim, a pillar garnish, a quarter trim, and the like.
(2) In the above embodiment, an example is shown in which two product parts of the resin foam molded body are provided on the left and right sides, and a non-product part is provided between the two product parts. It is not limited to. The present invention can be applied even when one or three or more product parts are provided.
(3) In the above-described embodiment, the molten resin is injected and supplied with the pair of molds in a semi-closed state in the molten resin injection supply process, but the present invention is melted with the pair of molds completely closed. The present invention can be applied even when resin is injected and supplied.

It is a perspective view which shows the external appearance of a resin foaming molding. It is a top view of a resin foaming molding. It is the sectional view on the AA line of the resin foam molding shown in FIG. It is process drawing of a skin material setting process. It is process drawing of a molten resin injection supply process. It is process drawing of a resin foam molding process. It is process drawing of a resin foam molding process. It is an expanded sectional view of the forming part formed between a pair of molds.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Resin foam molding 12 ... Product part 14 ... Non-product part 16 ... Resin foam 18 ... Skin material 20a, 20b ... Mold 22 ... Molten resin 30 ... Molding part 32 ... Product part molding part 34 ... Non-product part molding Portion 36 ... Injection port 40 ... Injection devices C1, C2 ... Dimensions between both molds

Claims (3)

A method for producing a resin foam molded body in which a skin material and a resin foam are integrated,
Setting the skin material between a pair of molds that can be opened and closed;
A step of injecting and supplying a molten resin to which a foaming agent is added to a molding portion for molding the resin foam molded body formed between the two molds in a state where the pair of molds are closed or semi-closed. When,
The molten resin injected into the molding part by opening the pair of molds by a predetermined distance after a predetermined time has elapsed since the molten resin was filled in the entire area of the molding part or the pair of molds were completely closed. And the step of integrating the skin material and the resin foam, and molding the resin foam molded body,
The resin foam molded product has a product part that is a part used as a product and a non-product part that is a part that is not used as a product.
The molded part formed between the pair of molds corresponding to the resin foam molded body includes a product part molded part that is an area for molding the product part and an area for molding the non-product part. And a non-product part molded part,
An injection port for injecting molten resin into the molded part is provided in the non-product part molded part,
The resin foam molding characterized in that the dimension between the two molds of the non-product part molding part at the time of supplying the molten resin is set larger than the dimension between the two molds of the product part molding part. Body manufacturing method. It is a manufacturing method of the resin foam molding according to claim 1,
When the thickness of the skin material is T (mm),
The method for producing a resin foam molded article, wherein a dimension between both molds of the product part molding part is set within T + 5 mm. It is a manufacturing method of the resin foam molding according to claim 1 or 2,
When the dimension between both molds of the product part molding part is C1 (mm) and the dimension between both molds of the non-product part molding part is C2 (mm),
C2 = C1 + α (α is 0.5 mm or more and 2.0 mm or less)
A method for producing a resin foam molded article, wherein

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