JP2009248435A - Molding method of foamed resin molding and mold for molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a molding method of a foamed resin molding adopting a method of thin wall molding a foaming resin material and then subjecting a mold to an inching opening operation and foaming a foaming resin material and a mold for molding capable of positively preventing occurrence of a weld line, allowing further thinning during the thin wall molding, and setting high foaming magnification to achieve reduced weight. <P>SOLUTION: By laminating a ceramic embossed sheet 60 having superior heat insulating property on a mold face of a movable side mold 30, degradation of heat of the resin is suppressed during the thin wall molding of the foaming resin material M, fluidity of the foaming resin material M is enhanced in a high temperature state, the occurrence of the weld line WL is prevented, thinning is made to the maximum, and the setting range of the foaming magnification is widened. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for molding a foamed resin molded product, in which a foamed resin material is thinly molded in a molding die, the mold is opened, and then the foamed resin material is foamed to form a foamed resin molded product, and In particular for molding dies, even when resin is supplied through a multi-point gate, the weld line is not generated, the appearance is excellent, and the thickness during thin molding can be set as thin as possible. Therefore, the present invention relates to a molding method and a molding die for a foamed resin molded product in which the expansion ratio can be set more freely.

  8 and 9 show the automobile door trim 1 formed into a required shape by foam molding, FIG. 8 is a front view, and FIG. 9 is a sectional view. And, as shown in FIG. 10, the conventional molding die 2 used when molding the automobile door trim 1 is an injection for supplying the movable side die 3, the fixed side die 4 and the foamed resin material M, as shown in FIG. And machine 5. More specifically, the movable mold 3 is connected to a press ram 3a and configured to be able to advance and retract by a predetermined stroke. On the other hand, the fixed-side mold 4 is provided with a hot runner 4a and a gate 4b serving as a resin passage for the foamed resin material M supplied from the injection machine 5, and is formed between the molds 3 and 4 through the resin passage. The foamed resin material M is injected and filled into the cavity C.

  By the way, in order to foam the foamed resin material M with high accuracy, first, the mold clearance between the movable side mold 3 and the fixed side mold 4 is set narrow, and the foamed resin material M is quickly injected into the cavity C. A molding method is often used in which filling is performed and thin molding is performed, and thereafter the movable side mold 3 is opened to slightly widen the clearance, and then the foamed resin material M is foamed.

  Then, as shown in FIG. 11, when the thin mold is performed by narrowing the mold clearance between the movable mold 3 and the fixed mold 4, the foamed resin material M is filled into the cavity C from a plurality of gates. However, since the resin heat is taken from the mold surfaces of both molds 3 and 4 and the resin temperature decreases at a remote location far from the gate 4b, for example, as shown in FIG. A weld line WL is generated at a site where the resin supplied from G2 meets, and the appearance performance tends to be deteriorated. In addition, in order to eliminate the weld line WL, it is necessary to apply coating to the product surface, and there is a drawback that the total cost increases. Incidentally, as shown in FIG. 11, an etching stop 6 is processed as a product design surface on the mold surface of the movable mold 3. Also, as shown in FIG. 12, it is difficult to set the plate thickness dimension to 1.9 mm or less during thin-wall molding, and the final product thickness is set to 2.5 to 3.3 mm. Since it cannot be set high, there has been a problem that the weight reduction of the product cannot be achieved. Incidentally, a method for injecting a foamed resin molded product, in which the movable side mold 3 is opened, is described in detail in Patent Document 1.

JP 2002-120252 A

  As described above, in the conventional injection molding method for foamed resin molded products, first, after the foamed resin material M is formed into a thin wall, the mold clearance in which the movable side mold 3 is opened and foamed is adjusted in two stages. Although a method is known, when the foamed resin material M is formed into a thin wall, since the foamed resin material M is filled into the cavity C with a multipoint gate, a weld line WL is easily generated, and in particular, a movable surface that becomes a product surface. When the etching stop 6 is used on the side surface 3 of the side mold, the weld line WL tends to come out strongly, and there is a problem of deteriorating the appearance performance. In order to eliminate the weld line WL, the product surface is coated. However, it has been pointed out that the painting cost increases and the cost increases.

  Further, in the conventional method, since the foamed resin material M is easily cooled, it is difficult to form a thin wall, and it is difficult to reduce the thickness at the time of thin wall molding to 1.9 mm or less. Therefore, the expansion ratio must be set low, Since the setting of the expansion ratio is limited, there is a problem that the weight reduction of the product cannot be achieved.

  The present invention has been made in view of such circumstances, and is a molding method and a molding die for a foamed resin molded product employing a multi-point gate method, and after first thinly molding between molds having a narrow clearance This is a two-stage drive system in which the movable mold is opened and foamed resin material is foamed. The weld line is eliminated, the appearance looks good, and the thickness during thin molding is maximized. Since it can set, it aims at providing the shaping | molding method and molding die of the foaming resin molded product which can set a foaming ratio in the wide range.

  In order to achieve the above object, the present invention sets a mold clearance between the movable side mold and the fixed side mold to be narrow and clamps, and injects a foamed resin material into a cavity formed between both molds. In the molding method of the foamed resin molded product, after performing the thin-wall molding by filling, opening the movable side mold and foaming the foamed resin material to mold the foamed resin molded product, The mold surface is laminated with ceramic-squeezed sheets with high heat insulation properties, so that when foaming resin material is injected and filled, the fluidity of the foaming resin material is increased to make the thickness as thin as possible. It is possible to mold and expand the expansion ratio setting range.

  Further, the molding die used in the method of the present invention is set by narrowing the mold clearance between the movable side die and the fixed side die, and clamped, and the foamed resin material is placed in the cavity formed between the two dies. A molding mold for a foamed resin molded product, in which a thin mold is formed by injection filling, and then the movable side mold is opened, and a foamed resin material is molded by foaming the foamed resin material, The mold is composed of a movable mold that can move by a predetermined stroke and a fixed mold that is provided with an injection machine that supplies a foamed resin material, and the mold of the movable mold that is the product surface of the foamed resin molded product. On the surface, ceramic drawn sheets with excellent heat insulation are laminated and integrated, which improves fluidity during thin molding of foamed resin materials and eliminates the weld line, expanding the foaming ratio setting range It is characterized by that.

  Here, the foamed resin molded product can be applied to a wide range of uses such as interior parts for automobiles such as door trims, luggage trims, trunk trims, interior materials for railway vehicles and homes, and various packaging containers. In addition, the foamed resin material has a configuration in which a foaming agent is added to a general-purpose thermoplastic resin, and the thermoplastic resin includes a polyethylene resin, a polypropylene resin, a polystyrene resin, a polyethylene terephthalate resin, and a polyvinyl alcohol resin. , Vinyl chloride resin, polyamide resin, polyacetal resin, polycarbonate resin, ionomer resin, acrylonitrile / butadiene / styrene (ABS) resin, etc. can be used. Inorganic blowing agents such as sodium bicarbonate can be used.

  Next, the molding die used in the method of the present invention includes a movable die, a fixed die, and an injection machine connected to the fixed die. The mold surface of the movable mold is the product surface, and the mold surface of the fixed mold is the product back surface. Further, a ceramic drawn sheet having a high heat insulating property is laminated on the mold surface of the movable mold. For example, a sheet-like ceramic sheet is laminated and integrated on a mold surface by vacuum baking or the like.

  The present invention also relates to a method for molding a foamed resin molded product, in which a movable mold and a fixed mold are clamped, and a foamed resin material is injected and filled into a cavity with a narrow mold clearance. Thin-wall molding is performed. After that, it is characterized by performing two-step mold clearance adjustment by opening the movable side mold and foaming, but the mold clearance at the time of thin wall molding should be set in the range of 1.5 to 1.6 mm Thus, the expansion ratio can be increased.

  Therefore, according to the method of the present invention, since the ceramic sheet with excellent heat insulation is laminated on the mold surface of the movable side mold, when the foamed resin material is injected and filled into the cavity to form a thin wall, Resin heat is not lost to the movable mold side compared to the etching restriction of, and injection filling into the cavity is possible while maintaining the resin temperature at a high temperature, thus suppressing generation of weld lines and fluidity. Therefore, the mold clearance can be set as thin as possible and the foaming ratio can be set high.

  As described above, according to the molding method and the molding die of the foamed resin molded product according to the present invention, the foamed resin material is injected and filled into the cavity between the movable side die and the fixed side die, and the mold clearance is obtained. When forming a thin-walled product with a narrowing, the heat-resisting heat is taken away by the movable-side mold, because a ceramic-squeezed sheet with high thermal insulation is laminated on the mold surface of the movable-side mold (product side mold). The foamed resin can be flowed at a high temperature and no weld line is generated, so the appearance of the foamed resin molded product is enhanced and post-processing such as painting on the product surface to hide the weld line is also possible. This is not necessary and has the effect of reducing the processing cost.

  Furthermore, according to the molding method and the molding die of the foamed resin molded product according to the present invention, since the ceramic drawn sheet with high heat insulation is laminated on the mold surface of the movable die, the resin remains at a high temperature. Since it can be flowed and thin-walled molding is possible, if the foaming reaction is performed by opening the movable mold according to the thickness of the final product, the foaming ratio can be set high, and the product specification Thus, by expanding the degree of freedom in setting the expansion ratio, the product can be lightened.

  Hereinafter, embodiments of the method for molding a foamed resin molded article and a molding die according to the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the gist of the present invention is as described in the claims, and the contents of the embodiments described below are merely examples of the present invention.

  FIGS. 1 to 7 show an embodiment of the present invention. FIG. 1 is a front view showing a door trim formed by the method of the present invention, FIG. 2 is a sectional view showing the structure of the door trim, and FIG. FIG. 4 to FIG. 7 are explanatory views showing the respective steps of the method of the present invention.

  1 and 2, the door trim 10 molded by the method of the present invention is a specification that is installed on the interior surface side of the left door panel of the vehicle, is configured from a single foamed resin molded product, and is desired by a molding method described later. The armrest 11 is formed in a curved shape, and in the center, the armrest 11 is formed so as to bulge indoors so that an occupant can rest on his / her elbow. Inside the armrest 11, an inside handle escutcheon 12 is provided. Below the armrest 11, a door pocket opening 13 capable of accommodating equipment is opened, and a door trim is provided on the front side of the door pocket opening 13. A speaker grille 14 is provided integrally with 10 or separately. In FIG. 1, G1 and G2 indicate gate positions for convenience.

  The door trim 10 has a uniform thickness of 2.5 to 3.3 mm. As shown in an enlarged view in FIG. 2, skin layers 10b are laminated on the front and back sides of the central foam layer 10a. ing. The drawing surface of the door trim 10 is faithfully transferred from the molding die, and the door trim 10 is molded by a multi-point gate method, but a weld line WL (shown in FIG. 8) is generated. There is no, and it has excellent appearance performance.

  As described above, the door trim 10 is excellent in appearance performance and is made of a foamed resin molded product, thus greatly contributing to weight reduction. The molding material for the door trim 10 is a structure in which a foaming agent is added to a general-purpose thermoplastic resin. Examples of the thermoplastic resin include a polyethylene resin, a polypropylene resin, a polystyrene resin, a polyethylene terephthalate resin, and polyvinyl alcohol. Resin, vinyl chloride resin, polyamide resin, polyacetal resin, polycarbonate resin, ionomer resin, acrylonitrile / butadiene / styrene (ABS) resin, etc. can be used, and foaming agents include organic foams such as azodicarbonamide An inorganic foaming agent such as an agent or sodium bicarbonate can be used. In this embodiment, a foamed resin material in which a foaming agent (sodium bicarbonate) is added to a polypropylene resin is used.

  Next, the configuration of the molding die 20 used for molding the door trim 10 will be described with reference to FIG. The molding die 20 is generally composed of a movable side die 30, a fixed side die 40, and an injection machine 50 provided continuously with the fixed side die 40. More specifically, the movable mold 30 can be moved forward and backward by a predetermined stroke amount by driving the press ram 31, and a hot runner serving as a passage for the foamed resin material M supplied from the injection machine 50 is provided in the fixed mold 40. 41 and a gate 42 are provided. In addition, the code | symbol 43 shows the ejector pin for protruding the foamed resin molded product after shaping | molding. By the way, a feature of the molding die 20 according to the present invention is that a ceramic drawn sheet 60 with high heat insulation is laminated on the mold surface of the movable side die 30. The ceramic drawn sheet 60 is laminated on the mold surface of the movable mold 30 by vacuum baking. However, in the chemical vapor deposition method, the physical vapor deposition method, and the thermal spraying method, the ceramic drawn sheet 60 is formed on the mold surface of the movable mold 30. A hard ceramic film may be formed.

  Next, each step of the present invention will be described with reference to FIGS. First, as shown in FIG. 4, the movable mold 30 is lowered to the bottom dead center by driving the press ram 31, and the mold clearance d <b> 1 between the movable mold 30 and the fixed mold 40 is minimized. This mold clearance d1 can be set to 1.9 mm or less by laminating ceramic drawn sheets 60 with high heat insulation, and preferably the mold clearance d1 is adjusted to 1.5 to 1.6 mm. good.

  Then, the foamed resin material M is injected and filled into the cavity C from the injection machine 50 through the hot runner 41 and the gate 42 with the mold clearance d1 set narrow. Although the resin flow at this time is shown in FIG. 5, since the ceramic drawn sheet 60 with high heat insulation is laminated on the mold surface of the movable side mold 30, there is little decrease in the resin heat. Even if the resin supplied from 42 is associated, a weld line (indicated by WL in FIG. 8) is not generated. The above is the thin molding of the foamed resin. Next, when the thin-wall molding with the mold clearance set to d1 is completed, as shown in FIG. 6, the movable side mold 30 is opened and the mold clearance between the molds 30, 40 is set to d2. Inducing a foaming reaction of the foamed resin molded product. At this time, as shown in FIG. 7, with respect to the mold clearance d1 at the time of thin molding which has been adjusted to 1.5 to 1.6 mm, the mold clearance d2 at the time of foaming reaction is set to 2.5 to 3.3 mm. . Therefore, although the product thickness is not different from the conventional one, the plate thickness at the time of thin molding (equal to the mold clearance d1 at the time of thin molding) can be set to be thin, so that the foaming ratio can be adjusted higher accordingly, contributing to weight reduction.

  As described above, the method according to the present invention can be achieved by simply adopting a simple mold configuration in which the ceramic drawn sheet 60 with excellent heat insulation is laminated and integrated on the mold surface of the movable mold 30. The weld line WL, which was unavoidable with foamed resin molded products that use the gate system, can be eliminated, so that the appearance performance can be maintained well and the product surface after molding can be abolished, increasing productivity. Since the expansion ratio can be adjusted freely, it can contribute to weight reduction. In the above-described embodiment, the ceramic drawn sheet 60 is laminated only on the mold surface of the movable mold 30, but the ceramic sheet without drawing is laminated on the mold surface of the fixed mold 40, A ceramic sheet may be stacked on both sides of the mold 30 and the fixed mold 40.

  Although the embodiment has described the molding method and molding die of the door trim 10, interior parts other than the door trim 10, for example, interior parts for automobiles such as luggage trim and trunk trim, or interior materials and packaging containers for railway vehicles and homes. It can be applied to general foamed resin molded articles such as. In the embodiment, the ceramic drawn sheet 60 is laminated on the mold surface of the movable mold 30 by vacuum baking. However, the chemical vapor deposition method, the physical vapor deposition method, or the The ceramic diaphragm may be formed by a thermal spraying method.

It is a front view which shows the door trim shape | molded by the method of this invention. It is the II-II sectional view taken on the line in FIG. It is explanatory drawing which shows the whole structure of the shaping die used for shaping | molding of the door trim shown in FIG. It is explanatory drawing which shows the state at the time of thin wall shaping | molding in the shaping | molding method of the door trim which uses the shaping die shown in FIG. It is explanatory drawing which shows the state of the resin flow at the time of thin molding in the method of this invention. It is explanatory drawing which shows the state at the time of the foaming reaction in the molding method of the door trim which uses the shaping die shown in FIG. It is explanatory drawing which shows the thickness change before foaming of the foamed resin molded product shape | molded by the method of this invention, and after foaming. It is a front view which shows the door trim shape | molded by the conventional construction method. It is the IX-IX sectional view taken on the line in FIG. It is explanatory drawing which shows the shaping | molding method of the conventional door trim. It is explanatory drawing which shows the resin flow at the time of thin molding in the shaping | molding method of the conventional door trim. It is explanatory drawing which shows the thickness change before foaming of the conventional door trim, and after foaming.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Door trim 10a Foamed layer 10b Skin layer 20 Molding die 30 Movable side die 31 Press ram 40 Fixed side die 41 Hot runner 42 Gate 50 Injection machine 60 Ceramic sheet C Cavity M Foamed resin material

Claims (2)

The mold clearance between the movable mold (30) and the fixed mold (40) is set narrow and the mold is clamped, and the foamed resin material (M) is placed in the cavity formed between the molds (30, 40). After performing thin-wall molding by injection filling, the movable side mold (30) is opened and the foamed resin material (M) is foamed to form the foamed resin molded product (10). In the molding method of
On the mold surface of the movable side mold (30), a ceramic drawn sheet (60) having a high heat insulation property is laminated so that the foamed resin material (M) is injected and filled with the foamed resin material (M). A method for molding a foamed resin molded product, characterized in that by increasing the fluidity of M), it is possible to perform thin-wall molding in which the thickness is set as thin as possible, and the expansion ratio setting range is expanded. The mold clearance between the movable mold (30) and the fixed mold (40) is set narrow and the mold is clamped, and the foamed resin material (M) is placed in the cavity formed between the molds (30, 40). After performing thin-wall molding by injection filling, the movable side mold (30) is opened and the foamed resin material (M) is foamed to form the foamed resin molded product (10). A molding die (20) of
The molding die (20) is composed of a movable side die (30) movable by a predetermined stroke and a fixed side die (40) provided with an injection machine (50) for supplying the foamed resin material (M). A ceramic drawn sheet (60) rich in heat insulation is laminated and integrated on the mold surface of the movable mold (30), which is the product surface of the foamed resin molded product, so that the foamed resin material (M ) Is a mold for foamed resin molded products, which has improved fluidity during thin-wall molding, enables the elimination of weld lines, and expands the expansion ratio setting range.

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