JP2002166464A - Molding method of resin panel - Google Patents

Abstract

(57) [Problem] To provide a method of manufacturing a resin panel having high rigidity and good external appearance. SOLUTION: A core material 4 is made to face between two thermoplastic resin sheets 2 and 3 whose peripheral edges are clamped, and in this state, the thermoplastic resin sheets 2 and 3 are heated and softened to form a plurality of pieces on one surface. Is set between a pair of molds 9 and 10 having a plate-shaped cavity 11 having concave portions formed therein. Then, the molds 9 and 10 are closed and two thermoplastic resin sheets 2 and 3 and a core material are formed at the periphery of the mold. 4 and heat-sealed, and high-pressure gas is supplied between the thermoplastic resin sheets 2 and 3 in the cavities 11 of the molds 9 and 10 to press the thermoplastic resin sheets 2 and 3 against the inner surface of the cavity 11. To shape.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin panel used as a hood, a door panel, a tailgate, a trunk lid, a trunk board, a rear package tray and the like of an automobile and a method of molding the same. The outer plate surface required for such a method for manufacturing a vehicle outer plate and appearance quality is bonded to the inner plate surface (stiffener) required to be formed into a complex uneven shape for securing rigidity. The present invention relates to an improvement in a method of manufacturing a composite material sheet in which another member such as a core material is sandwiched between two resin sheets by using sheet blow molding.

[0002]

2. Description of the Related Art Resin bonnets and door panels have been proposed because they have the advantages of being lightweight, not rusting, and being easy to mold, and an outer plate using a highly rigid thermosetting resin has been actually used. It is manufactured in.

[0003] However, thermosetting resins have high rigidity, but are difficult to recycle. For this reason, a proposal for increasing the rigidity of a panel using a thermoplastic resin which is recyclable but has low rigidity is disclosed in JP-A-8-323842. The content is that the honeycomb structure is blow-molded between two resin skin materials.

[0004]

Generally, in order to increase the rigidity of the resin panel, it is conceivable to form one of the resin skin members in an uneven shape. However, Japanese Patent Laid-Open No.
Since the panel disclosed in Japanese Patent No. 42 has a structure in which a honeycomb structure of a core material and two resin skin materials are in close contact over the entire surface, molding of a vehicle outer plate (particularly, a stiffener) cannot be performed. Further, since a part of the honeycomb structure is cut into the surface material in the thickness direction, sink marks and the like due to molding shrinkage are conspicuous, the honeycomb pattern appears to the outside, and the appearance is not good.

[0005]

In order to solve the above-mentioned problems of the prior art, a method of forming a resin panel according to the present invention is a method of forming a resin panel in which a core material is disposed between two heat-softened thermoplastic resin sheets. A method of forming a resin panel in which a core material is sandwiched between two thermoplastic resin sheets by facing these between a pair of molds and then closing the molds.
A recess is formed in at least one cavity surface of the mold, and a high-pressure gas is supplied between two thermoplastic resin sheets located in the cavity during molding to press the thermoplastic resin sheet against the cavity inner surface, A convex portion having a hollow inside was formed in a part of the thermoplastic resin sheet by the concave portion of the cavity.

In the above, the core material is preferably a mat made of a thermoplastic resin fiber, a fiber coated with a thermoplastic resin, or a fiber in which a thermoplastic resin fiber is entangled with a natural fiber, but may be a foamed thermoplastic resin mat. . By using such a fiber mat, the fibers are thermally fused to the thermoplastic sheet, and the strength is greatly improved.

In another aspect of the present invention, the two thermoplastic synthetic resin sheets are clamped at their peripheral edges in such a manner that a predetermined closed space is formed therebetween, and the two sheets are heated and softened. Thereafter, a method of forming a resin panel is sandwiched between a pair of upper and lower molds inside the above-described clamp position on the periphery, and compressed air is introduced into a closed space between the two sheets to bring both sheets into close contact with inner surfaces of the upper and lower molds. In, one of the two thermoplastic synthetic resin sheets is located below, the other sheet is located above, and the core material is also located with a gap provided between the other sheet, After sandwiching two thermoplastic synthetic resin sheets and a core material by a mold, a pressurized gas is supplied to the closed space and blow molding is performed to partially separate the other sheet from the core material, thereby forming a shape. did.

At this time, if one of the resin sheet and the core material is pressed in advance to form a state in which the entire core material is cut into the resin sheet material, the fusion strength at the interface can be further increased.

[0009]

Embodiments of the present invention will be described below. FIG. 1 is a sectional view of a door panel formed by a resin panel molding method according to the present invention.
A fiber mat 4 serving as a core material is filled between two thermoplastic resin sheets 2 and 3. The thermoplastic resin sheet 2 is an outer panel, and the thermoplastic resin sheet 3 is an inner panel.
Is formed with a convex portion 3a serving as a stiffener extending in a direction perpendicular to the paper surface, thereby increasing the rigidity of the inner panel.

The thermoplastic resin sheets 2 and 3 are made of, for example, resins such as polyvinyl chloride, polymethyl methacrylate, polystyrene, polypropylene, polycarbonate, polyethylene terephthalate, polyamide, and modified polyphenylene oxide, but are not limited thereto.

The fiber constituting the fiber mat 4 is a resin in which the surface of a fiber such as a thermoplastic resin fiber or a glass fiber is coated with a thermoplastic resin, or a fiber in which a thermoplastic resin fiber is entangled with a natural fiber. . The thermoplastic resin fibers constituting the fiber mat 4 or the thermoplastic resin on the fiber surface are fused to each other by heat, and the inner surfaces of the thermoplastic resin sheets 2 and 3 and the fiber mats in contact with the inner surface The fibers constituting 4 are also fused to each other. Note that a foamed thermoplastic resin mat can be used as the mat, and the mat may be any material that can be fused to the thermoplastic resin sheet 2.3.

The above resin panel 1 is manufactured by blow molding. The process will be described with reference to FIGS.
First, as shown in FIG. 2A, the thermoplastic resin sheet 2 is clamped by the clamper 5 and the thermoplastic resin sheet 3 is clamped by the clamper 6.
And the fiber mat 4 is clamped by the clamper 7, respectively.
The fiber mat 4 is positioned between the thermoplastic resin sheets 2 and 3, and in this state, the fiber mat 4 is inserted between the upper and lower heaters 8 as shown in FIG. The clampers 5, 6, 7 are, for example,
It has a frame shape of the same dimensions. Heater 8,8
For example, those capable of rapid heating such as near infrared rays are preferable. The heaters 8 may be moved.

When the thermoplastic resin sheets 2 and 3 are heated by the heaters 8 and softened until blow molding is possible, as shown in FIG. 3, the thermoplastic resin sheets 2 and 3 are inserted between them. The fiber mat 4 is set between the upper and lower molds 9 and 10 for blow molding. In order to form a cavity in the thermoplastic resin sheet 2, the molds 9 and 10 have cavities 11 in which one surface is flat and the other surface is provided with a plurality of recesses 9 a. The fiber mat 4 is also indirectly heated by a heater and is in a state where it can be fused.

Next, as shown in FIG.
Close 10. Then, the thermoplastic resin sheets 2 and 3 and the fiber mat 4 are overlapped and pressed at the periphery of the mold to form a body.
Inside it, it is molded according to the shape of the mold cavity 11. In addition, the thermoplastic resin sheets 2 and 3 and the fiber mat 4
By making the total thickness of the mold before molding larger than the thickness of the thinnest part of the mold cavity 11, it is possible to reliably obtain a product that follows the shape of the mold cavity 11.

Here, a compressed air supply passage 12 is formed in the upper mold 9, and a needle 13 connected to the supply passage 12 protrudes from the cavity surface. Therefore, when the upper and lower molds 9 and 10 are closed, the needle 13 breaks through the thermoplastic resin sheet 3 and penetrates into the fiber mat 4. Therefore, compressed air is blown through the needle 13. Then, the thermoplastic resin sheets 2 and 3 are pressed against the cavity surfaces of the upper and lower molds 9 and 10, and a product that accurately follows the mold cavity shape is obtained. That is, a convex portion 3a is formed on a part of the thermoplastic resin sheet 3 so as to follow the concave portion 9a of the cavity.

The needle 13 is preferably provided in a mold for molding the back surface of the product in order to make a hole in the sheet. Further, the number of the needles 13 may be plural, and by blowing and discharging the cooling air using the plural needles, the internal cooling effect can be enhanced and the product dispensing cycle can be shortened.

Thereafter, as shown in FIG. 5, the product is taken out by releasing the mold, the peripheral edge is cut, and deburring and drilling are performed at necessary places to obtain the resin panel 1 shown in FIG.

In the above-described embodiment, the mat is made of a resin in which the surface of a fiber such as a thermoplastic resin fiber or a glass fiber is coated with a thermoplastic resin. Good.

In the above-described embodiment, the mat 4 is clamped by the clamper 7 so as to face between the thermoplastic resin sheets 2 and 2. However, the mat 4 is simply placed on the thermoplastic resin sheet 3. You may.

Next, another embodiment of the present invention will be described with reference to FIGS. The same parts as those in the above embodiment are denoted by the same reference numerals, and the description thereof will be omitted. FIG.
FIG. 3 is a cross-sectional view of a state in which a thermoplastic resin sheet and a core material are preheated. FIGS. 6A and 6B show the clamper 6.
Then, the thermoplastic resin sheet 3 integrated with the thermoplastic resin sheet 2 and the fiber mat 4 as the core material by the clamper 5 is clamped, and inserted between the upper and lower heaters 8 in that state. Indicates preheating.

Next, the preheated thermoplastic resin sheets 2 and 3 and the fiber mat 4 are laid one on top of the other, and the space between the inner surface of the thermoplastic resin sheet 3 and the outer surface of the fiber mat 4 as shown in FIG. Is further heated so as to provide a closed space 14.

When the thermoplastic resin sheets 2 and 3 are heated by the heaters 8 and softened until blow molding is possible, as shown in FIG. 8, the thermoplastic resin sheets 2 and 3 are inserted between them. The fiber mat 4 is set between the upper and lower molds 9 and 10 for blow molding.

Further, as shown in FIG.
Close 0. Then, the thermoplastic resin sheets 2 and 3 and the fiber mat 4 are overlapped and pressed at the periphery of the mold to form a body, and the inside thereof is shaped according to the shape of the mold cavity 11. By making the total thickness of the thermoplastic resin sheets 2 and 3 and the fiber mat 4 before molding larger than the thickness of the thinnest portion of the mold cavity 11, the shape of the mold cavity 11 is surely copied. The product is obtained.

Here, a compressed air supply passage 12 is formed in the upper mold 9, and a needle 13 connected to the supply passage 12 protrudes from the cavity surface. Therefore, when the upper and lower molds 9 and 10 are closed, the needle 13 breaks through the thermoplastic resin sheet 3 and penetrates into the fiber mat 4. Therefore, compressed air is blown through the needle 13. Then, the thermoplastic resin sheets 2 and 3 are pressed against the cavity surfaces of the upper and lower molds 9 and 10, and a product that accurately follows the mold cavity shape is obtained. That is, a convex portion 3a is formed on a part of the thermoplastic resin sheet 3 so as to follow the concave portion 9a of the cavity.

The needle 13 is a thermoplastic resin sheet 3
In order to make a hole in the product, it is preferable to provide it in a mold for molding the back surface of the product. Further, the number of the needles 13 may be plural, and by blowing and discharging the cooling air using the plural needles, the internal cooling effect can be enhanced and the product dispensing cycle can be shortened.

Thereafter, as shown in FIG. 5, the product is taken out by releasing the mold, the peripheral portion is cut, and deburring and drilling are performed at necessary places to obtain the resin panel 1 shown in FIG. .

Next, an example of a method for fusing the thermoplastic resin sheet 2 and the fiber mat 4 as a core material in the above embodiment will be described with reference to FIGS. As shown in FIG. 9, the thermoplastic resin sheet 2 is inserted between the heaters 8 and heated while being clamped by the clampers 5 and 5.

Then, as shown in FIG. 10, the heated thermoplastic resin sheet 2 and the fiber mat 4 are placed between the upper and lower dies 15 and 16 for pressing. The inner surface of the mold 15 is a flat surface, while the inner surface 17 of the mold 16 is formed with stoppers 18, 18 for fixing the fiber mat 4.
The fiber mat 4 used at this time may be heated in advance to facilitate fusing.

Further, as shown in FIG.
Close 5,16. Then, the thermoplastic resin sheet 2 and the fiber mat 4 are pressed and fused by the upper and lower dies 15 and 16. Thereafter, the mold is released, and as shown in FIG. 12, the thermoplastic resin sheet 2 and the fiber mat 4 can be integrally taken out. As a method of manufacturing an integrated sheet, in addition to using the above-described press, a resin sheet and a fiber mat that are continuously heated may be pressure-bonded between rolls.

FIGS. 13 to 15 show enlarged sectional views of the integrated thermoplastic resin sheet 2 and fiber mat 4. FIG. FIG. 13 is a cross-sectional view of one layer of the thermoplastic resin sheet 2 and the fiber mat 4.
The impregnated portion 2 a is formed between the fiber mat 4 and the fiber mat 4. That is, the thermoplastic resin sheet 2 is melted by a certain thickness and impregnated into the core material 4 which is a fiber mat.

FIG. 14 is an enlarged sectional view of the thermoplastic resin sheet 2 made of a multilayer laminating sheet and the core material 4. The thermoplastic resin sheet 2 composed of a multi-layer laminated sheet is
On the fiber mat 4 side, a material 2c having a low melting point and excellent adhesiveness is used, and on the surface side of the resin sheet 2, a material 2b having a high melting point and excellent design properties, weather resistance and mechanical properties is used. As described above, when the thermoplastic resin sheet 2 is heated,
As shown in FIG. 15, the low melting point material 2c is melted and impregnated into the fiber mat 4 by pressing.

In the above-described embodiment, the fiber mat is a resin in which the surface of a fiber such as a thermoplastic resin fiber or a glass fiber is coated with a thermoplastic resin. However, the fiber mat is simply a fiber such as a glass fiber. Is also good.

[0033]

As described above, according to the method for forming a resin panel according to the present invention, a core material is inserted between two thermoplastic resin sheets to improve the strength and the like on one side of the sheet. A resin panel having a convex portion can be efficiently formed.

When the core material is a mat made of a plastic resin fiber or a fiber coated with a thermoplastic resin,
Since the bonding strength between the two thermoplastic resin sheets and the mat increases, a resin panel having higher rigidity can be formed.

In addition, since a nonwoven fabric or mat is used as the core material, the quality of the outer plate surface is good, and the core material can be thinned out, leading to a reduction in weight.

Further, since the thermoplastic resin sheet serving as the outer panel having a small required amount of elongation is arranged below the fiber mat serving as the core material, which is likely to be in contact with the fiber mat, it is possible to minimize the quality deterioration due to the contact. In addition, since the thermoplastic resin sheet serving as the inner panel is laid out with a gap therebetween and is partially pressed by a mold, the non-pressed portion can be easily separated from the core material during subsequent shaping and can be shaped.

Further, by welding the thermoplastic resin sheet as the outer panel and the fiber mat as the core material in advance, the fusion strength is improved, and defects such as waving of the plate surface of the outer panel are obtained. Can be eliminated,

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a door panel obtained by a resin panel molding method according to the present invention.

FIGS. 2A and 2B are cross-sectional views showing a process until a resin sheet is heated.

FIG. 3 is a cross-sectional view showing a state where a heated resin sheet according to the present invention is set between molds.

FIG. 4 is a sectional view showing a blow molding state according to the present invention.

FIG. 5 is a sectional view showing a release state according to the present invention.

FIGS. 6A and 6B are cross-sectional views showing a process of preheating a resin sheet and a core material.

FIG. 7 is a sectional view showing heating of a resin sheet and a core material.

FIG. 8 is a sectional view showing a state where a heated resin sheet according to the present invention is set between molds.

FIG. 9 is a cross-sectional view illustrating a process of heating a resin sheet serving as an outer panel.

FIG. 10 is a sectional view showing a state in which a resin sheet and a core material serving as an outer panel are set between molds.

FIG. 11 is a cross-sectional view showing a state where a resin sheet and a core material serving as an outer panel are pressed.

FIG. 12 is a cross-sectional view showing a release state.

FIG. 13 is an enlarged cross-sectional view after pressing a single-layer resin sheet and a core material.

FIG. 14 is an enlarged sectional view of a two-layer resin sheet and a core material.

FIG. 15 is an enlarged cross-sectional view after pressing a two-layer resin sheet and a core material.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Door panel (resin panel), 2, 3 ... Thermoplastic resin sheet, 4 ... Fiber mat (core material), 5, 6, 7 ...
Clamper, 8 ... heater, 9, 10, 15, 16 ...
Mold: 11: cavity, 12: compressed air supply passage, 13: needle, 14: closed space.

Claims (4)

[Claims] The present invention relates to a thermoplastic resin sheet comprising: a core material disposed between two heat-softened thermoplastic resin sheets; A method of molding a resin panel with a core material sandwiched between the molds, wherein a recess is formed on at least one cavity surface of the mold, and the recess is formed in the cavity during molding.
A high-pressure gas is supplied between the two thermoplastic resin sheets to press the thermoplastic resin sheet against the inner surface of the cavity, and the concave portion of the cavity forms a convex portion having a hollow inside in a part of the thermoplastic resin sheet. Characteristic resin panel molding method. 2. A peripheral portion of two thermoplastic synthetic resin sheets is clamped in such a manner that a predetermined closed space is formed therebetween, and the two sheets are heated and softened. In a method of molding a resin panel, the two sheets are sandwiched between a pair of upper and lower molds on the inner side, and compressed air is introduced into a closed space between the two sheets to bring both sheets into close contact with the inner surfaces of the upper and lower molds. One of the resin sheets is positioned below, the other sheet is positioned above, and the core material is also positioned with a gap provided between the two sheets. After sandwiching the resin sheet and the core material, a pressurized gas is supplied to the closed space and blow molding is performed so that the other sheet is partially separated from the core material to form the resin panel. Molding method Law. 3. The core material is a nonwoven fabric made of a thermoplastic resin,
The method according to claim 2, wherein the resin mat is a fiber mat formed by coating a non-resin fiber such as glass with a thermoplastic resin. 4. The core material and one sheet are supplied into a mold in a state in which the core material and the one sheet are fused in advance.
3. The method for molding a resin panel according to item 1.