JP2003200515A - Laminated resin material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminated resin material adaptable in order to obtain a laminated resin molded product having excellent dimensional accuracy and strength in its bent region. <P>SOLUTION: As the resin foam 22a becoming the intermediate layer 22 of the laminated resin molded product 20, resin foam is characterized in that the mean diameter of small air bubbles 24b present in the region W2 on the side of a resin cover 4a becoming the surface layer 4 of the laminated resin molded product 20 is smaller than the mean diameter of large air bubbles 24a present in the region W1 on the side of a resin substrate material body 2a becoming the substrate material layer 2 of the molded product 20. After the substrate material body 2a is molded by a molding machine, it is held to the projected mold 6 of a molding machine separate from the molding machine and a sheetlike laminate (laminated resin material) 38, which is obtained by bonding the resin foam 22a and the resin cover 4a (skin), and is arranged between the resin substrate material body 2a and a recessed mold 7. Subsequently, the molding machine is clamped and the sheetlike laminate 38 and the resin substrate material body 2a are mutually bonded in a cavity 8, and the gas in the cavity 8 is removed under vacuum to mold the sheetlike laminate 38. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated resin material capable of obtaining a laminated resin molded product which is excellent in dimensional accuracy and strength of a bent portion or a curved portion.

[0002]

2. Description of the Related Art FIG. 10 shows a schematic vertical cross-sectional view of a laminated resin molded product according to the prior art and an enlarged view of its essential part. The laminated resin molded article 1 is formed by joining a base material layer 2, an intermediate layer 3 and a surface layer 4 in this order. Each of the layers 2 to 4 is made of a resin material. Among them, the intermediate layer 3 is a resin foam in which bubbles 5 having substantially the same diameter are dispersed substantially uniformly.

The laminated resin molded product 1 is manufactured as follows.

First, after clamping the injection molding apparatus, a molten resin (molten metal) is injected into the cavity of the injection molding apparatus,
By cooling and solidifying the molten metal, a resin base material body made of a resin molded body is produced.

Next, after opening the mold, the resin base material is taken out and held in one mold of a vacuum forming apparatus, and in this state, an adhesive is applied on the surface of the resin base material.

Next, between the other mold of the vacuum forming apparatus and the resin base material, a sheet-like laminate composed of a resin foam and a resin cover joined to the resin foam is formed into a resin foam. Is placed so as to face the resin base material body, and then the mold is clamped. By this mold clamping, the sheet-shaped laminated body is roughly bent and deformed along the shape of the mold.

Further, the sheet-shaped laminate is brought into close contact with this mold by drawing a vacuum of the gas in the cavity through the mold on the side which comes into contact with the sheet-shaped laminate to make a negative pressure in the cavity. As a result, the sheet-shaped laminate is finely bent and deformed along the shape of the mold, and the grain shape is transferred to the surface layer 4, and the bent portion R having a predetermined surface shape and bending rate is formed.
(See FIG. 10) is molded.

After exhausting the gas in the cavity,
The compressed gas is supplied to the cavity through a passage formed in advance in the mold in which the sheet-shaped laminate is closely attached to the cavity, or the passage is opened to the atmosphere, and the mold and the resin substrate in close contact with the resin base body are preliminarily formed. The gas in the cavity is evacuated through the formed gas suction hole. As a result, the resin foam is pressed toward the resin base body, so that they are firmly bonded to each other via the adhesive.

Finally, after the supply of the compressed gas to the cavities and the discharge of the gas in the cavities are completed, the mold is opened to form the base layer 2 made of a resin base body and the intermediate layer 3 made of a resin foam. Further, the laminated resin molded product 1 in which the surface layer 4 made of the resin cover is bonded to each other in this order is obtained.

The laminated resin molded product 1 manufactured in this manner is used, for example, as an instrumental panel for automobiles.

By the way, in the method for manufacturing a laminated resin molded article according to the above-mentioned conventional technique, the bending portion R of the laminated resin molded article 1 is used.
There is a possibility that a product having a shrinkage or a product in which the strength of the bent portion R is not good is manufactured.

The reason for this is that the ductility of the resin foam as the intermediate layer 3 is poor, and therefore the negative pressure inside the cavity causes the sheet-shaped laminate to adhere to the mold and bend portion R.
This is because the resin foam 3a is not sufficiently spread as shown in FIG. On the other hand, the resin cover 4a
Since the resin cover 4a is bonded to the resin foam 3a, the resin cover 4a does not spread. Eventually, this causes a shrinkage in the bent portion R.

In FIG. 11, reference numeral 2a is a base material layer 2.
The resin base material body used as this is shown. Further, reference numerals 6 and 7 are a convex type and a concave type provided in the vacuum forming apparatus (not shown), and a cavity 8 is formed by clamping both types of molds 6 and 7. Further, reference numerals 9 and 10 are convex type 6 and concave type 7.
Gas intake holes formed respectively in the
Is a hole formed in the resin base material 2 a and communicating with the gas intake hole 9 of the convex mold 6.

Further, since the resin foam 3a is spread at the bent portion R, the thickness of the resin foam 3a becomes thin, and therefore the strength becomes lower than that of the flat portion. Moreover, the cracks 12 are generated due to the expansion of the bubbles 5, and as a result, the bubbles 5 and 5 may be deformed and connected. When such a situation occurs, the strength of the bent portion R is further reduced.

That is, the method for manufacturing a laminated resin molded product according to the prior art has a problem that the laminated resin molded product 1 having excellent dimensional accuracy and strength of the bent portion R cannot be manufactured with high yield.

On the other hand, Patent Document 1 discloses a resin foam body in which the diameter of foam in the central portion is larger than that in the surface layer portion. According to this Patent Document 1, when the resin foam and a skin material made of a resin material or cloth are bonded at high temperature, no unevenness is generated in the resin foam, and the resulting laminate is obtained. In the body, it is said that air does not enter between the skin material and the resin foam.

[0017]

[Patent Document 1] JP-A-9-12762 ([001
3], [0014])

[0018]

However, in Patent Document 1, the evaluation in the case where the resin foam is vacuum-formed alone is made in detail, but the skin material and the resin foam are integrally vacuum-formed. Therefore, no attempt has been made to suppress the occurrence of shrinkage of the skin material at this time.

That is, a technique for suppressing the occurrence of shrinkage of the surface layer 4 when the resin foam 3a and the resin cover 4a are integrally vacuum-molded as described above has not been established.

The present invention has been made in order to solve the above-mentioned problems, and a laminated resin material capable of obtaining a laminated resin molded product in which a bent portion is molded with high dimensional accuracy and the strength of the bent portion is excellent. The purpose is to provide.

[0021]

In order to achieve the above object, the present invention is a laminated resin material having a foam and a skin made of a resin bonded to the foam, the foam comprising: In (1), the average diameter of the bubbles present on the side where the epidermis is joined is smaller than the average diameter of the bubbles present on the side away from the epidermis.

The average diameter as used herein means that the resin constituting the surface layer side region or the base material layer side region of the flat portion of the intermediate layer is cut into 1 mm ³ rectangular parallelepipeds, and 1 mm ³ of the rectangular parallelepiped is used.
It was obtained by measuring the diameters of all the bubbles except the bubbles cut into the sides, obtaining the sum, and dividing this sum by the number of the measured bubbles.

With such a structure, the laminated resin material and the resin base material are joined by the cavity of the molding apparatus, and the gas in the cavity is exhausted to exhaust the laminated resin material and the resin base. When manufacturing a laminated resin molded product composed of a material, shrinkage at the bent portion is significantly suppressed, and therefore a laminated resin molded product in which the bent portion is molded with high dimensional accuracy can be obtained. Moreover, since the foamed body is rich in ductility, the strength of the bent portion is improved as compared with the laminated resin molded article according to the prior art.

In this case, the average diameter of the bubbles existing in the surface layer side region of the intermediate layer is 1/20 to 3/4 of the average diameter of the bubbles existing in the base layer side region of the intermediate layer. preferable. This is because the dimensional accuracy and strength of the bent portion are surely secured.

The thickness of the base layer side region is preferably 1/6 to 1/2 of the thickness of the surface layer side region. If it is less than 1/6, shrinkage is likely to occur. Further, if it is much more than 1/2, the manufacturing cost of the resin foam increases, and eventually the manufacturing cost of the laminated resin molded product also increases.

Further, it is preferable that the resin forming the surface layer side region is crosslinked. This allows
This is because the strength of the bent portion is further improved.

Such a laminated resin material can be preferably used as a member constituting an interior member arranged in the interior of an automobile.

A preferred example of the interior member is an instrumental panel.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the laminated resin material according to the present invention will be described below in detail with reference to the accompanying drawings in relation to a laminated resin molded product having the same. The components corresponding to those shown in FIGS. 10 and 11 are designated by the same reference numerals, and detailed description thereof will be omitted.

FIG. 1 is a schematic vertical sectional view of a laminated resin molded product according to this embodiment. The laminated resin molded product 20 is formed by bonding the base material layer 2, the intermediate layer 22, and the surface layer 4 to each other in this order. Each of the layers 2, 22 and 4 is made of a resin material, of which the intermediate layer 22 is a resin foam such as polypropylene (PP) resin or polyethylene (PE) resin.
On the other hand, as a constituent material of the base material layer 2, PP resin or acrylonitrile-butadiene-styrene copolymer (ABS)
Examples of the material for the surface layer 4 include resins such as thermoplastic polyolefin (TPO) resin and vinyl chloride (PV).
C) resin, ABS resin, etc. are illustrated. In this case, the thickness ratio of the base material layer 2, the intermediate layer 22, and the surface layer 4 is 2 to
It is 6: 2 to 6: 0.3 to 1.

Here, the portion surrounded by the circle C1 in FIG. 1 is enlarged and shown in FIG. As shown in this FIG.
The intermediate layer 22 has a region W1 in which a plurality of large air bubbles 24a are substantially uniformly dispersed and a plurality of small air bubbles 24b having an average diameter smaller than that of the large air bubbles 24a. The region W1 is located on the base material layer 2 side, while the region W2 is located on the surface layer 4 side. In this case, the thickness of the region W2 is 1 / the thickness of the region W1.
It is about 2.

The diameters of the large bubbles 24a are substantially equal to each other.
The average diameter of the large bubbles 24a is usually about 1/20 to 3/10 of the thickness of the intermediate layer 22.

Similarly, the diameters of the small bubbles 24b are substantially equal to each other. The average diameter of the small bubbles 24b is
It is about 1/20 to 3/4 of the average diameter of a.

That is, for example, when the thickness of the intermediate layer 22 is about 3 mm, the thickness of the region W1 is about 2 mm, and the region W is about 2 mm.
2 has a thickness of about 1 mm, and the large bubbles 24a have an average diameter of about 0.1.
5 to 0.9 mm, the average diameter of the small bubbles 24b is about 0.007
It is 5 to 0.675 mm.

Further, a portion surrounded by a circle C2 in FIG. 1, that is, a bent portion R in the laminated resin molded product 20.
Is enlarged and shown in FIG. It is clear from FIG. 3 that the bent portion R has no shrinkage, and the small bubbles 24b in the vicinity of the bent portion R have slightly expanded, and no cracks have occurred.

Next, a method of manufacturing the laminated resin molded product 20 will be described. The method for manufacturing a laminated resin molded article according to the present embodiment includes a first step S1 of molding a resin base material body made of a resin molded body by a first molding apparatus and one mold of a second molding apparatus. A second step S2 of arranging a resin cover (skin) between the held resin base material and the other mold via a resin foam, and a third step of clamping the second molding device.
Step S3, a fourth step S4 of molding the resin cover by making the cavity of the second molding apparatus negative pressure through the other mold of the second molding apparatus, and the second step
And a fifth step S5 of molding the resin foam by making a negative pressure in the cavity through the mold holding the resin base material and the resin base material of the molding apparatus.

First, in the first step S1, as shown in FIG. 4, a lower die 30 and an upper die 32 which can be moved toward or away from the lower die 30 by being urged by an actuator mechanism (not shown) are shown. The resin base material body 2a is molded by an injection molding device (first molding device) that does not. Specifically, after the lower mold 30 and the upper mold 32 are brought into close contact with each other to form the cavities 34, 34, a molten metal obtained by melting PP resin or ABS resin is injected from an injection mechanism (not shown),
The molten metal is cavities 34, 34 through a passage (not shown).
Introduce to each. By cooling and solidifying this molten metal, two resin base materials 2a, 2a are obtained.

Here, the lower die 30 is provided with a plurality of protrusions (not shown). Therefore, in the obtained resin base materials 2a, 2a, as will be described later, the holes 11 are formed at the locations corresponding to the protrusions.

By urging the actuator mechanism (not shown), the upper die 32 is moved upward to open the die to expose the resin base materials 2a, 2a.

Next, in the second step S2, as shown in FIG. 5, the resin base materials 2a, 2a are held by the convex mold 6 of a vacuum forming device (second forming device) not shown. In this state, an adhesive (not shown) is applied to the surfaces of the resin base materials 2a, 2a.

The resin base material 2 held by the convex mold 6
A sheet-like laminated body (laminated resin material) 38 in which the resin foam 22a and the resin cover (skin) 4a are joined to the resin foam 22a is arranged between a and 2a and the concave mold 7 (FIG. 5). reference). As shown in the enlarged view of the main part of FIG. 5, in the sheet-shaped laminate 38, the resin foam 22a is the resin base material 2a.
Are arranged to face each other. As can be seen from the enlarged view of the main part of FIG. 5, the resin foam 22a includes a region W1 in which the large bubbles 24a exist and small bubbles 24b having an average diameter smaller than that of the large bubbles 24a. What is divided into the area W2 is used.

Here, the sheet-like laminated body 38 is, for example,
It is produced as follows.

First, a pellet-shaped PP resin or PE resin and a decomposable foaming agent are mixed in a mixer to obtain a mixture, which is extruded and molded into a sheet to obtain a sheet-shaped molded body.

Next, an electron beam is applied to one end surface of this sheet-shaped molded product. After the elapse of a predetermined time, the irradiation of the electron beam is terminated and the entire sheet-shaped compact is heat-treated. On this occasion,
The sheet-shaped molded product is divided into a portion where bubbles are likely to grow large (a portion made of a resin having a low degree of crosslinking) and a portion where bubbles are relatively hard to grow (a portion made of a resin having a high degree of crosslinking). Therefore, the obtained resin foam 22a is
It is divided into two regions W1 and W2 having different average diameters (see an enlarged view of a main part of FIG. 5). That is, the portion made of resin having a low degree of crosslinking becomes the region W1 in which the large bubbles 24a exist, while the portion made of resin having a high degree of crosslinking has small bubbles 24b having an average diameter smaller than that of the large bubbles 24a.
Is an area W2 in which is present.

While the resin foam 22a is produced as described above, the resin cover 4a is produced. That is,
Pellets of TPO resin, PVC resin, ABS resin, etc. are extruded or calendered to form a sheet-shaped resin cover 4a.

Next, the resin cover 4a is overlaid on the region W2 side of the resin foam 22a, and these are pressed from both the region W1 side of the resin foam 22a and the resin cover 4a side to be in close contact with each other in the heating furnace. To introduce. By performing the heat treatment in the heating furnace, the resin foam 22a and the resin cover 4a are fused, and as a result, the sheet-shaped laminate 38 is obtained.

In the second step S2, the sheet-shaped laminated body 38 obtained as described above and the resin mold bodies 2a, 2a and the concave mold 7 are formed.
Then, in a third step S3, the actuator mechanism (not shown) is urged to move the concave die 7 downward, and as shown in FIG. 6, the concave die 7 and the convex die 6 are clamped. Thus, the cavities 8 and 8 are formed. At this time, the sheet-shaped laminated body 38 is roughly bent and deformed along the shape of the concave mold 7, and the sheet-shaped laminated body 38 and the resin substrate body are bonded via the adhesive applied to the surfaces of the resin substrate bodies 2a and 2a. 2a and 2a are adhered to each other.

As shown in FIG. 7, which is an enlarged view of the vicinity of the bent portion R, that is, the portion surrounded by the circle C3 in FIG. 6, the convex mold 6 has a hole 11 in the resin base material 2a, 2a.
The gas intake hole 9 is provided at a position corresponding to. The concave die 7 is also provided with a gas intake hole 10. The gas intake holes 9 and 10 communicate with an intake pipe (not shown) connected to an intake port of an exhaust mechanism (not shown). That is, the gas in the cavities 8, 8 of this vacuum forming apparatus can be exhausted (evacuated) through the gas intake holes 9, 10 by the exhaust mechanism (not shown).

The evacuation from the gas intake holes 9 or 10 can be performed individually.

Next, in the fourth step S4, the exhaust mechanism (not shown) is urged to evacuate the gas in the cavities 8 and 8 from the gas intake holes 10 of the concave mold 7 to evacuate the cavities 8 and 8. Make negative pressure (see FIG. 6). Thereby, the sheet-shaped laminated body 38, that is, the resin cover 4a.
The resin foam 22a is further bent and deformed along the shape of the concave mold 7, and the grain shape on the surface of the concave mold 7 is clearly transferred to the resin cover 4a.

The region W2 of the resin foam 22a (see the enlarged view of the main part of FIG. 5) is rich in ductility because the small bubbles 24b existing in the region W2 have a small average diameter. Therefore, when the sheet-shaped laminate 38 is sucked, as shown in FIG.
The region W2 comes into close contact with the concave mold 7 via the resin cover 4a in a state where the small bubbles 24b are slightly expanded. Of course,
In response to this, the resin cover 4a also comes into close contact with the concave mold 7, so that the sheet-like laminated body 38 eventually comes into close contact with the concave mold 7 without shrinkage. Thereby, the laminated resin molded product 20
The dimensional accuracy of the bent portion R is significantly improved.

Moreover, the small bubbles 24b are only slightly expanded, and therefore, the occurrence of cracks starting from the small bubbles 24b is avoided. Moreover, as described above, the region W2 is made of a crosslinked resin. Therefore, the strength of the bent portion R does not decrease.

Next, in the fifth step S5, as shown in FIG. 8, the compressed gas is supplied to the cavities 8, 8 from the compressed gas supply mechanism (not shown) through the gas intake holes 10 (see FIG. 7) of the concave mold 7. . Alternatively, the gas intake hole 10 may be opened to the atmosphere. In this state, the gas in the cavities 8, 8 is evacuated by the exhaust mechanism (not shown) through the gas intake holes 9 of the convex mold 6 and the holes 11 formed in the resin base materials 2a, 2a. As a result, the resin foam 22a is firmly adhered and bonded to the resin base materials 2a, 2a adsorbed on the convex mold 6 via the adhesive, and as a result, the base material layer 2 made of the resin base material 2a, the resin Intermediate layer 22 made of foam 22a and surface layer 4 made of resin cover 4a
Laminated resin moldings 20, 2 in which are joined together in this order
Two 0s are formed.

After a lapse of a predetermined time, when the supply of the compressed gas to the cavities 8 and 8 and the evacuation of the gas in the cavities 8 and 8 are finished and the mold opening is performed, as shown in FIG. The two laminated resin molded products 20, 20 connected to each other by the sheet-shaped laminated body 38 are exposed.

Finally, if the sheet-like laminated body 38 connecting the two is cut and subjected to post-processing, bilaterally symmetrical laminated resin molded articles 20, 20 are obtained. Each of the bent portions R of the laminated resin molded products 20, 20 has excellent dimensional accuracy and strength. Therefore, the yield of the laminated resin molded product 20 is improved.

In the above embodiment, the resin foam 22a and the resin cover 4a are provided on the resin substrate 2a.
Although the sheet-like laminated body 38 in which and are joined to each other is joined, the resin foam 22a is joined to the resin base body 2a, and then the resin cover 4a is placed on the resin foam 22a.
You may make it join.

Further, the cutting of the sheet-like laminated body 38 for connecting the laminated resin molded products 20, 20 may be performed in the cavities 8, 8.

Furthermore, in this embodiment, the bent portion R has been described as an example, but even a curved portion will have no shrinkage and excellent strength.

[0059]

As described above, according to the present invention,
The average diameter of the bubbles present on the side where the resin skin is joined is smaller than the average diameter of the bubbles present on the side away from the skin, so compared to the laminated resin molded article according to the prior art,
The effect that a laminated resin molded product having excellent dimensional accuracy and strength of a bent portion can be obtained is achieved.

The above-mentioned effects are particularly remarkable at sharply bent portions. That is, even when a laminated resin molded product having a sharp bent portion is manufactured, it is possible to obtain a laminated resin molded product having high quality and excellent strength in which the surface layer of the bent portion has no shrinkage.

[Brief description of drawings]

FIG. 1 is a schematic vertical cross-sectional view of a laminated resin molded product according to the present embodiment.

FIG. 2 is an enlarged view of a portion surrounded by a circle C1 in FIG.

FIG. 3 is an enlarged view of a portion surrounded by a circle C2 in FIG.

FIG. 4 is a partially omitted vertical cross-sectional view showing a state in which a resin substrate is manufactured by a molding device.

FIG. 5 is a partially omitted vertical cross-sectional view showing a state in which a sheet-shaped laminated body is arranged between a resin base body and a concave mold, and an enlarged view of a main part of the sheet-shaped laminated body.

FIG. 6 is a partially omitted vertical cross-sectional view showing a state in which a gas inside the cavity is evacuated with the cavity formed.

7 is an enlarged view of an essential part of a portion surrounded by a circle C3 in FIG.

FIG. 8 is a partially omitted vertical cross-sectional view showing a state in which compressed gas is supplied into the cavity through the concave mold and the gas in the cavity is discharged from the convex mold.

FIG. 9 is a schematic vertical sectional view of a manufactured laminated resin molded product.

FIG. 10 is a schematic vertical cross-sectional view of a laminated resin molded product according to the prior art and an enlarged view of a main part thereof.

11 is a partially omitted vertical cross-sectional view showing a state in which a gas in a cavity is evacuated when the laminated resin molded product shown in FIG. 10 is manufactured.

[Explanation of symbols]

1, 20 ... Laminated resin molded product 2 ... Base material layer 2a ... Resin base material 3, 22 ... Intermediate layers 3a, 22a ... Resin foam 4 ... Surface layer 4a ... Resin cover 5, 24a, 24b ...
Bubble 6 ... Convex 7 ... Recessed 8, 34 ... Cavity 9, 10 ... Gas inlet 11 ... Hole 30 ... Lower 32 ... Upper 38 ... Sheet-like laminate R ... Bent portion W1, W2 ... Region

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hiroe Hashimoto             1-10-1 Shinsayama, Sayama City, Saitama Prefecture             Engineering Co., Ltd. F-term (reference) 4F100 AK01B AK04 AK07 AK74                       BA02 BA07 BA15 BA43B                       DJ01A GB32 JK01 JL04

Claims (3)

[Claims] 1. A laminated resin material having a foam and a skin made of a resin bonded to the foam, wherein in the foam, the average diameter of bubbles existing on the side where the skin is bonded is The laminated resin material is characterized in that it is smaller than the average diameter of bubbles existing on the side separated from the skin. 2. The laminated resin material according to claim 1, wherein the laminated resin material constitutes an interior member arranged in the interior of an automobile. 3. The laminated resin material according to claim 2, wherein the interior member is an instrumental panel.