JPH06134852A - Method for molding synthetic resin molded form using hollow structure plate - Google Patents

Abstract

PURPOSE:To mold a molded form having substantially uniform thickness, a high strength and beautiful both sides by setting a heated hollow structure plate, mold clamping vacuum molds, holding the plate between both molding surfaces, and evacuating both vacuum molds to suck by vacuum the plates to both molding surfaces. CONSTITUTION:A pair of liners 32, 33 disposed in parallel, and many ribs 34 for partitioning between the liners 32 and 33 in parallel in a longitudinal direction are provided. The liners 32, 33 use a hollow structure plate 31 molded by integrally extruding synthetic resin material such as olefin base resin, ABS resin, etc., and two vacuum molds 10, 20 opposed at an interval substantially equal to a thickness of the plate 31 at two molding surfaces at the time of mold clamping. The heated plate 31 is set between the opened molds 10 and 20. Then, the molds 10, 20 are clamped, the plate 31 is held between both the molding surfaces, the molds 10, 20 are evacuated to vacuum suck the plate 31 between both the molding surfaces.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for molding a synthetic resin molded article applicable to various fields such as automobile interior parts, packaging containers, civil engineering building materials, and the like. The present invention relates to a method of molding a synthetic resin hollow structure plate having a pair of liners and a large number of ribs partitioning the liners in parallel in the longitudinal direction into a molded product having a desired shape.

[0002]

2. Description of the Related Art A hollow structure plate of this type has many characteristics such as impact resistance, pressure resistance, water resistance, heat insulation, sound insulation, and light weight. Widely used in various fields such as processing into packages. Also, Japanese Utility Model Publication No. 54-159509 and Japanese Utility Model Publication No. 54-160.
No. 440, as shown in FIG.
After the heat-softened hollow structure plate 51 is set on the upper part of 1, the vacuum forming die 41 is depressurized and the hollow structure plate 51 is vacuum-sucked to the forming surface 42 thereof, so that the interior core material for automobiles, the heat insulation container, etc. A method of molding the synthetic resin molded product 61 is shown.

[0003]

However, the molding method of the synthetic resin molded product has the following problems. That is, as indicated by the chain line in FIG. 21, each part of the hollow structure plate 51 that has been softened by heating is easily bent by pressing or elongated by tension. For this reason, as shown in FIG. 20, at the opening edge portion 43 of the molding surface 42, the ribs 54 buckle due to the strong curvature of the liners 52 and 53, and the hollow structure plate 51 is likely to be thin accordingly. On the other hand, the molding surface 42
In the bottom corner portion 44 of the
Only this is strongly vacuumed to extend the ribs 54, and the hollow structure plate 51 tends to be thick only there. Opposite liner 53
Is not sucked in vacuum because the independent spaces 5 between the ribs 54 are
5 is open to the atmosphere at the end of the hollow structure plate 51, and the vacuum suction of the liner 52 on the molding surface side is the liner 53 on the opposite side.
This is because it is not transmitted to. As described above, when the thickness of the hollow structure plate 51 becomes uneven, the original characteristics such as impact resistance and pressure resistance are deteriorated, and the strength of the synthetic resin molded product 61 is reduced.

Therefore, the present inventor uses a plug 45 as shown by a chain line in FIG.
An attempt was made to push 1 into the molding surface 42 to bring them closer to each other.
According to this method, since the amount of deformation of the hollow structure plate 51 due to vacuum suction can be small, the above-mentioned problems can be alleviated, and the thickness of the hollow structure plate 51 can be made uniform. However, as shown in FIG. 22, the rib 54 is apt to buckle due to the pressing of the plug 45, and the liner 53 in contact with the plug 45 has an uneven wrinkle 56. The wrinkles 56 are considered to be due to uneven cooling of the liner 53 due to the plug 45.

Therefore, an object of the present invention is to prevent the ribs or buckling of the ribs of the hollow structure plate from being formed, and to mold a synthetic resin molded product having a substantially uniform thickness and high strength, and to provide a hollow structure. It is an object of the present invention to provide a novel method capable of transferring a molding surface of a vacuum molding die to a pair of liners of a plate to mold a beautiful synthetic resin molded product on both surfaces.

[0006]

In order to achieve the above object, in the method for molding a synthetic resin molded product using the hollow structure plate of the present invention, a pair of liners arranged in parallel at a distance is used. It has a large number of ribs that partition the liners parallel to each other in the longitudinal direction, and the ribs and the liner are integrally extruded from a synthetic resin raw material to form a hollow structure plate, and the two molding surfaces are hollow during mold clamping. After using two vacuum forming dies configured to face each other at an interval substantially equal to the thickness of the structure plate, after setting the heated hollow structure plate between the two vacuum forming dies opened, The vacuum forming die was clamped to sandwich the hollow structure plate between both forming surfaces, and the vacuum forming molds were depressurized to suck the hollow structure plate on both forming surfaces in vacuum.

Here, as the "thermoplastic synthetic resin",
Polypropylene resin, polyethylene resin, ABS resin,
AS resin, polystyrene resin, polycarbonate resin,
Examples thereof include acrylic resins, vinyl chloride resins and the like, and mixed resins thereof. Among them, resins having a high melt viscosity are preferable in that the temperature range in which an appropriate softened state is obtained is wide. The distance between "a pair of liners" is preferably 2 to 7 mm, and "ribs"
The mutual spacing is preferably 2 to 10 mm. Further, the “vacuum forming die” is not limited to a die having a specific structure, and an example using an electroformed shell or ceramic die having a large number of vent holes can be exemplified.
In particular, a non-electro-deposited portion generated in the early stage of electroforming grows with the progress of electroforming to form a large number of vent holes, which is a breathable electroformed shell (see, for example, Japanese Patent Publication No. 2-14434).
Is preferably used. In addition, "the two molding surfaces face each other at an interval substantially equal to the thickness of the hollow structure plate" does not necessarily mean the entire molding surface, and the position or degree that does not adversely affect the strength of the molded product. In, a part of the molding surface may face each other with an interval different from the thickness of the hollow structure plate.

Further, when the heated hollow structure plate is set between the two vacuum forming dies which are opened, a breathable decorative skin material may be arranged on at least one surface of the hollow structure plate. it can. Examples of the "decorative skin material" include textile products such as non-woven fabrics and woven fabrics, and synthetic resin products such as soft resin sheets and foamed resin sheets. The decorative skin material needs to have air permeability in order to sufficiently vacuum suction the hollow structure plate therethrough, and if it does not have air permeability, if it is provided with air permeability by needle hole processing or the like. Good. Further, the decorative skin material preferably has extensibility, and when it does not have extensibility, it may be imparted with extensibility by preheating or the like.

[0009]

According to the method for molding a synthetic resin molded article of the present invention,
When the two vacuum forming dies are clamped, the two forming surfaces sandwich the hollow structure plate with almost no change in the thickness, and the pair of liners of the hollow structure plate are vacuum-sucked. The thickness of the hollow structure plate is maintained as it is, without the ribs curving or buckling and part of the hollow structure plate becoming thin, or conversely, the ribs extending and partly thickening of the hollow structure plate. It is possible to mold a synthetic resin molded product having high strength. Also, by providing a fine uneven pattern such as a grain pattern, a cloth pattern, a stitch pattern, a wood pattern on one or both of the two molding surfaces, or by making the other or both of them a non-patterned smooth surface, one or both Since the state of these molding surfaces can be transferred to the liner, a synthetic resin molded article with a beautiful surface can be molded.

Further, when the heated hollow structure plate is set between the two vacuum forming dies which are opened, the breathable decorative skin material is overlaid on at least one liner of the hollow structure plate. When the two vacuum forming molds are clamped and the hollow structure plate is sandwiched between the two molding surfaces and vacuum sucked, the hollow structure plate is vacuum sucked through the decorative skin material and the decorative skin material is softened by heating. Attached to the liner. In particular, when the decorative skin material is a fiber product (nonwoven fabric, woven fabric, etc.) or a roughened synthetic resin sheet, the fibers and the rough surface are embedded in the surface portion of the softened liner, Firmly integrated. Also, when the decorative skin material is made of the same material as the hollow structure board (for example, when both are vinyl chloride), the decorative skin material is fused to the surface of the softened liner. , Firmly integrated.

[0011]

EXAMPLE A first example in which the present invention is embodied in a method of molding a quadrangular truncated pyramid-shaped synthetic resin molded product 1 as shown in FIG. 12 will be described with reference to FIGS. 1 to 11. .
First, FIGS. 1 to 6 show a method of manufacturing a vacuum molding die used in the present molding method, and the procedure is as follows. As shown in FIG. 1, after a model 2 having the same shape as the desired synthetic resin molded product 1 is formed from wood (synthetic resin, plaster, wax, or other material), cowhide 4 having a grain pattern 3 is formed.
(Suede, cloth, or other material having a fine concavo-convex pattern may be used.) Is attached only to the upper surface of the base of the model 2 to form the master model 5.

As shown in FIG. 2, the master model 5
A reverse embossed pattern 6 by transferring the embossed pattern 3 was provided by injecting silicon rubber (other material having low adhesiveness may be used) on the surface of (1) and curing it. The intermediate mold 7 is formed and peeled off. Figure 3
As shown in FIG. 3, by injecting an epoxy resin or other reaction curable material on the surface of the intermediate mold 7 (the injection frame and the like are not shown) and curing it, the reverse embossed pattern 6 is transferred to obtain the embossed pattern 8 The mother die 9 having the above is formed, and this is peeled off.

According to the method described in Japanese Examined Patent Publication No. 2-14434, the air-permeable electroformed shell 1 as shown in FIG.
1 is manufactured. That is, a thin conductive film (not shown) having minute non-conductive portions is formed on the surface of the mother die 9 by spraying a mixed solution of a paste silver lacquer, a vinyl chloride lacquer solution and a butyl acetate solution. . When this master block 9 is immersed in an electrolyte solution (not shown) that does not substantially contain a surfactant such as sodium lauryl sulfate, and the electroconductive film is electroformed, a breathable electroformed product as shown in FIG. 4 is obtained. A shell 11 is formed.
The air-permeable electroformed shell 11 is formed with a large number of vent holes 12 formed by penetrating a small non-electro-deposited portion that naturally occurs in the non-conductive portion of the conductive film while expanding the diameter as electroforming proceeds. . Further, the embossed pattern 8 is formed on the molding surface 13 of the air-permeable electroformed shell 11.
The reverse embossed pattern 14 is formed by the transfer.

A first vacuum forming mold (concave mold) 10 as shown in FIG. 5 is assembled from the breathable electroformed shell 11. That is,
The support frame 15 is attached to the rear peripheral portion of the air-permeable electroformed shell 11, and the base 16 is attached to the support frame 15 to form a decompression chamber on the back surface of the air-permeable electroformed shell 11. The decompression chamber is filled with a mixture of a large number of metal particles and an epoxy resin, and the epoxy resin is used to harden the spaces between the metal particles so that the air permeability is not lost. .) Is formed to back up the back surface of the air-permeable electroformed shell 11. Note that glass beads, sand, ceramic particles, or the like can be used instead of the metal particles, or a backing having a completely different structure can be used. Then, a decompression device 30 such as a vacuum pump may be connected to the decompression chamber via a valve 28 or the like.

As shown in FIG. 5, the air-permeable electroformed shell 11
A sheet-like wax 18 having a thickness of 5 mm, which is the same as that of the hollow structure plate 31 described later, is curved and adhered to the molding surface 13. A mixture of a large number of glass beads and an epoxy resin is applied to the back surface of the sheet-like wax 18 in a substantially constant thickness,
An epoxy resin is used to solidify the space between the glass beads so as not to lose air permeability, thereby forming an air permeable resin shell 21 having a smooth patterning surface 22 with no pattern. The sheet-like wax 18 may be removed after the air-permeable resin shell 21 is peeled off.

A second vacuum molding die (convex) 20 as shown in FIG. 6 is assembled from the breathable resin shell 21. That is,
A support frame 23, a base 24, a backing 25 and the like similar to the first vacuum molding die 10 may be provided on the back surface of the breathable resin shell 21, and the decompression device 30 may be connected to the decompression chamber via a valve 29 or the like. Both vacuum forming dies 1 manufactured as described above
For 0 and 20, the two molding surfaces 13 and 22 are 5 m when the mold is clamped.
Clamping device (not shown) so that they face each other at an interval of m
Mounted on. In this embodiment, the first vacuum forming mold (concave mold) 10 is arranged as an upper mold, and the second vacuum forming mold (convex mold) 20 is arranged as a lower mold.

The hollow structure plate 3 used in the present molding method
As shown in FIG. 7, 1 is a pair of liners 32 and 33 arranged in parallel with each other, and the liners 32 and 33.
With a large number of ribs 34 partitioning the spaces in parallel to the longitudinal direction,
In addition, the ribs 34 and the liners 32 and 33 are formed by extruding a polypropylene resin material integrally, and a large number of elongated independent spaces 35 are provided between the ribs 34.
Are sectioned. The thickness of the hollow structure plate 31 is 5 m
m, spacing between both liners 32, 33 is about 3 mm, rib 34
The mutual distance between the two is 5 mm.

Now, FIGS. 8 to 12 show a main forming method performed by using the first and second vacuum forming dies 10 and 20 and the hollow structure plate 31, and the procedure is as follows. First,
As shown in FIG. 8, the hollow structure plate 31 is held horizontally by sandwiching the peripheral edge of the hollow structure plate 31 with clamps 26, and is appropriately heated from above and below by a heater 27 to be softened without excess or deficiency. The appropriate heating temperature of the hollow structure plate 31 is 160 to 21.
The temperature is 0 ° C, more preferably 180 to 200 ° C.

Subsequently, as shown in FIG. 9, the hollow structure plate 31 is set between the first vacuum forming die 10 and the second vacuum forming die 20, and then the first vacuum forming die 10 is lowered. By raising the second vacuum forming die 20, the hollow structure plate 31 is moved to the first vacuum forming die 1 by the second vacuum forming die 20.
Push it to zero.

Then, as shown in FIG. 10, both the vacuum forming dies 10 and 20 are clamped, the hollow structure plate 31 is sandwiched between the two forming surfaces 13 and 22, and both vacuum forming dies are formed by the pressure reducing device 30. The synthetic resin molded product 1 is molded by depressurizing the depressurizing chambers 10 and 20 and vacuum suctioning the hollow structure plate 31.

At this time, as shown in FIG. 11, one of the liners 32 is vacuum-sucked from the ventilation holes 12 of the air-permeable electroformed shell 11 to the molding surface 13, so that the surface of the liner 32 has the reverse grain pattern. Sharp grain pattern 3 by transferring 14
6 is shaped. Further, since the other liner 33 is vacuum-sucked to the molding surface 22 from between the metal particles of the breathable resin shell 21, the surface of the liner 33 becomes a smooth surface with no pattern. In addition, the facing distance between both molding surfaces 13 and 22 is made equal to the thickness of the hollow structure plate 31, and as described above, both liners 3 are formed.
Since the ribs 34 are curved and buckled, a part of the hollow structure plate becomes thin as in the conventional case because the vacuum suction is applied to the parts 2 and 33, and conversely, the rib 34 extends and a part of the hollow structure plate becomes thick. Therefore, it is possible to mold the synthetic resin molded product 1 having a high strength in which the thickness of the hollow structure plate 31 is maintained as it is.

Thereafter, the two vacuum forming dies 10 and 20 are opened, and the formed synthetic resin molded article 1 is released. Finally,
As shown by the chain line in FIG. 12, the unnecessary edge portion 38 may be cut off from the synthetic resin molded product 1. As shown in FIG. 11, a concave portion 19 forming a character on a part of the air-permeable electroformed shell 11
By providing a portion (that is, a portion in which both molding surfaces 13 and 22 face each other with a gap larger than the thickness of the hollow structure plate 31), the liner 32 is vacuum-sucked into this recess 19 and, as shown in FIG. The embossed character 37 can be shaped.

Next, in order to confirm the effect of the present embodiment, the synthetic resin molded product 1 of the test example and the comparative example as shown in FIGS. 13 (a) and 13 (b) is molded, and the synthetic resin molded product 1 is molded. Then, a compression test as shown in FIG.

The hollow structure plate 31 used for this molding is made of polypropylene resin and has a thickness of 5 mm and a rib interval of 5 mm.
It is a product having a basis weight of 1500 g / m ² (manufactured by Ube Nitto Kasei Co., Ltd .: trade name Dunplate A-5-150), and this was cut into 420 mm square and molded.

The tensile / compression tester used in the compression test is, as shown in FIG. 13C, a base 101, a machine frame 102 erected on the base 101, and the base 101. A pedestal 104 installed above via a load cell 103 for detecting a compressive load, and a crosshead 1 for moving up and down in the machine frame 102.
05 and a general one. The synthetic resin molded product 1 is set between the pedestal 104 and the crosshead 105 so as to be sandwiched by two pressing plates 106 (500 mm square), and the crosshead 105 is lowered at a compression speed of 50 mm / min to perform a compression test. I went.

[Test Example] The synthetic resin molded article 1 of the test example is
A first vacuum forming mold (concave mold) and a second vacuum forming mold (convex mold) which have the same basic structure as the first vacuum forming mold 10 and the second vacuum forming mold 20 of the embodiment but differ only in the shape of the forming surface (both are (Not shown) was used and molded in the same manner as in the example. That is,
After heating the hollow structure plate 31 to 180 ° C. and setting it between both vacuum forming dies, both vacuum forming dies are clamped to sandwich the hollow structure plate between both forming surfaces, and both vacuum forming dies are depressurized. 1 by vacuum suctioning the hollow structure plate on both molding surfaces.
As shown in 3 (a) and 3 (b), a synthetic resin molded product 1 having a dome-shaped convex portion 1a having an outer diameter of 380 mm and a height of 70 mm was molded. As described in the above-mentioned Examples, the synthetic resin molded product 1 has a sharp textured pattern and a smooth surface, and the ribs (particularly the opening corner portion and the inner bottom corner portion of the dome-shaped convex portion 1a) are also buckled and stretched. None, it was molded to a uniform thickness. The maximum compressive breaking load (average value of 5 pieces) in the compression test of this test example is 5 as shown in FIG.
It was 48 kgf.

[Comparative Example A] The synthetic resin molded article of Comparative Example A was molded in the same manner as the conventional example shown in FIG. 20 using only the first vacuum molding die (concave mold) of the test example. That is, after the hollow structure plate was heated to 180 ° C. and set on the first vacuum forming die arranged upward, only the vacuum forming mold was decompressed and the hollow structure plate was vacuum-sucked to the forming surface. A synthetic resin molded product having the same shape as was molded. In this synthetic resin molded product, the ribs at the opening corner portion and the inner bottom corner portion of the dome-shaped convex portion buckled, and the thickness was uneven.
Then, the maximum compressive breaking load of this comparative example A was 416 kgf as shown in FIG.

[Comparative Example B] The synthetic resin molded article of Comparative Example B was the same as that of Comparative Example A except that a plug as shown by a chain line in FIG. 20 was used and a hollow structure plate was formed before vacuum suction. A synthetic resin molded product having the same shape as that of the test example was molded by using a method of pushing the molding surface to bring it closer. In this synthetic resin molded product, the ribs also buckled and the liner had wrinkles. The maximum compressive breaking load of this comparative example B was 484 kgf as shown in FIG.

Next, a method of molding a synthetic resin molded product according to the second embodiment of the present invention will be described with reference to FIGS. This example is different from the first example only in that a breathable decorative skin material is integrated with one surface of the hollow structure plate at the same time when the hollow structure plate is molded. Therefore, the same members as those in the first embodiment are designated by the same reference numerals as those in the first embodiment and their description will be omitted.

Also in this embodiment, the first vacuum forming die 10 and the second vacuum forming die 20 having the same structure as the first embodiment are used, but the first vacuum forming die (concave die) 10 is arranged as a lower die. Then, the second vacuum forming mold (convex mold) 20 is arranged as an upper mold.

As shown in FIG. 15, a breathable decorative skin material 40 is placed directly above the opened first vacuum molding die 10. Then, as shown in FIG. 16, the heated hollow structure plate 31 is set directly above the decorative skin material 40.
Next, as shown in FIG. 17, the first vacuum forming die 10 and the second vacuum forming die 20 are clamped, and the hollow structure plate 31 and the decorative skin material 40 are first vacuumed by the second vacuum forming die 20. The hollow structure plate 31 and the decorative skin material 40 are sandwiched between the two molding surfaces 13 and 22 while being pressed into the molding die 10, and the decompression device 30 decompresses the decompression chambers of both vacuum molding dies 10 and 20. The synthetic resin molded product 1 is molded by vacuum suction of 31.

At this time, since the hollow structure plate 31 is vacuum-sucked through the decorative skin material 40, the one liner 32 which is softened by heating strongly abuts on the decorative skin material 40, and the decorative skin material 40. Is attached to the surface of the liner 32. Further, similarly to the first embodiment, the synthetic resin molded product 1 having a high strength, in which the thickness of the hollow structure plate 31 is maintained as it is, is molded.

Thereafter, the two vacuum forming dies 10 and 20 are opened, and a molded synthetic resin molded article 1 as shown in FIG. 18 is formed.
Release. Finally, as in the first embodiment, the unnecessary edge portion 38 may be cut off from the synthetic resin molded product 1.

Next, in order to confirm the effect of this embodiment, the molding method of this embodiment is applied in the above-mentioned test example (FIG. 13), and synthetic resin molding in which a non-woven fabric as a decorative skin material is integrated. I tried molding a product (not shown). As the non-woven fabric, a needle punch mat (unit weight: 200 g / m ² ) made of polypropylene fiber having air permeability and extensibility was used. The formed synthetic resin molded article had a non-woven fabric adhered to one side thereof without wrinkles. When I tried to peel the non-woven fabric from the molded product, it was difficult because the fibers of the non-woven fabric were firmly embedded in the surface of the molded product, and when I tried to peel it off forcibly, the non-woven fabric was cut. As described above, according to this example, a decorative skin material such as a non-woven fabric can be attached to the surface of a synthetic resin molded article without using an adhesive.

The synthetic resin molded product having the hollow structure plate in which the decorative skin material is integrated as described above makes the best use of its impact resistance, heat insulating property, lightness, etc., for example, as shown in FIG. Ceiling material 111, rear parcel shelf 112,
It can be applied to the spare tire cover 113 and the like.

The present invention is not limited to the configuration of the above-described embodiment, and may be embodied with modifications within the scope not departing from the spirit of the invention, for example, as follows. (1) To transfer and form a sharp fine uneven pattern on both sides of a synthetic resin molded product, or to form a smooth surface with no pattern on both sides. (2) Forming a part of the hollow structure plate 31 to be thicker than the original thickness, and using that part as a reinforcing rib or a mounting seat for other parts.

[0037]

As described above in detail, according to the method for molding a synthetic resin molded product using the hollow structure plate according to the invention described in claim 1, the rib of the hollow structure plate is prevented from being curved or buckled. In addition to being able to mold a synthetic resin molded product that has a substantially uniform thickness and high strength, the molding surface of the vacuum molding die is transferred to a pair of liners of the hollow structure plate to create a beautiful synthetic resin molded product on both sides. It can be molded.

Further, according to the method for molding a synthetic resin molded product using the hollow structure plate according to the second aspect of the invention, the rib of the hollow structure plate is prevented from being curved or buckled as in the above invention. , A synthetic resin molded product having a substantially uniform thickness and high strength can be molded, and a decorative skin material for at least one liner, without using an adhesive,
It can be attached at the same time as molding.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a master model for manufacturing a first vacuum forming mold used in an example of the present invention.

FIG. 2 is a sectional view of an intermediate mold formed from the master model.

FIG. 3 is a sectional view of a mother die formed from the intermediate die.

FIG. 4 is a cross-sectional view of a breathable electroformed shell formed from the mother mold.

FIG. 5 is a cross-sectional view of a first vacuum forming die assembled using the air-permeable electroformed shell and a gas-permeable resin shell formed on the first vacuum forming die.

FIG. 6 is a cross-sectional view of a second vacuum forming die assembled using the breathable resin shell.

FIG. 7 is a perspective view of a hollow structure plate used in an example.

FIG. 8 is a schematic view of a heating process of the hollow structure plate.

FIG. 9 is a cross-sectional view when the heated hollow structure plate is sandwiched by both vacuum forming dies in the first embodiment.

FIG. 10 is a sectional view of both vacuum forming dies when the dies are clamped.

11 is an enlarged cross-sectional view of the main part of FIG.

FIG. 12 is a perspective view of a synthetic resin molded product molded according to the first embodiment.

13A is a perspective view showing a synthetic resin molded article of a test example, FIG. 13B is a sectional view of the same, and FIG. 13C is a front view showing a compression test method.

FIG. 14 is a graph showing compression test results of the same test example and comparative example.

FIG. 15 is a cross-sectional view when the decorative skin material is arranged immediately above the first vacuum forming mold in the second embodiment.

FIG. 16 is a cross-sectional view when a heated hollow structure plate is set just above the decorative skin material.

FIG. 17 is a sectional view of both vacuum forming dies when the dies are clamped.

FIG. 18 is a perspective view of a synthetic resin molded product molded according to the first embodiment.

FIG. 19 is a schematic view showing an example of application of the synthetic resin molded product to an automobile interior material.

FIG. 20 is a sectional view showing a conventional method for molding a synthetic resin molded product.

FIG. 21 is an enlarged cross-sectional view of the hollow structure plate in the molding method.

FIG. 22 is an enlarged sectional view of the same hollow structure plate.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Synthetic resin molded product 10 1st vacuum molding die 11 Breathable electroformed shell 13 Molding surface 20 2nd vacuum molding die 21 Breathable resin shell 22 Molding surface 31 Hollow structure board 32 Liner 33 Liner 34 Rib 40 Decorative skin material

Claims (2)

[Claims] 1. A pair of liners arranged in parallel at a distance, and a plurality of ribs partitioning the liners in parallel with each other in the longitudinal direction, and the ribs and the liner are made of a synthetic resin raw material integrally. A hollow structure plate extruded and molded,
Using two vacuum forming dies configured such that the two forming surfaces face each other at an interval substantially equal to the thickness of the hollow structure plate when the mold is clamped, and heating is performed between the two vacuum forming dies that are opened. After setting the hollow structure plate, clamp both vacuum forming dies to sandwich the hollow structure plate between both forming surfaces, depressurize both vacuum forming dies and vacuum suction the hollow structure plate to both forming surfaces. A method for molding a synthetic resin molded product using a characteristic hollow structure plate. 2. When setting a heated hollow structure plate between two vacuum forming dies that have been opened, a breathable decorative skin material is arranged on at least one surface of the hollow structure plate. A method for molding a synthetic resin molded article using the hollow structure plate according to claim 1.