JPH06328481A - Manufacture of automotive interior component - Google Patents

Abstract

PURPOSE:To improve the appearance of a product and impart an excellent cushioning property thereto by avoiding chipping of surface member due to melted resin and eliminating heat damage when the surface member and resin core material are to be molded integrally by press molding. CONSTITUTION:An unfoamed material for a surface member 30, containing foaming agent, is charged in press molding upper and lower molds 50 and 60. The surface member 30 is foamed by the heat of a melted resin M injected into the upper and lower molds 50 and 60 in press molding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing automobile interior parts such as automobile door trims.

[0002]

11 and 12 are a front view and a sectional view showing an automobile door trim which is one of automobile interior parts. The automobile door trim 1 is formed into a desired curved surface shape and has a shape-retaining shape. And a resin core material 2 having rigidity for mounting on a vehicle body panel, a skin material 3 which is provided with decorativeness and cushioning property is integrally attached to the surface of the resin core material 2.
Recently, as a molding method for the resin core material 2, a mold press molding method tends to be frequently used.

According to this mold press molding method, a semi-molten resin material is distributed and fed into the upper and lower molds for mold press molding, and the upper and lower molds are clamped to obtain interior parts having excellent moldability with less material loss. It is possible.

That is, in order to manufacture the automobile door trim 1 shown in FIGS. 11 and 12 by the mold press molding method, as shown in FIG. 13, it is possible to perform engagement pressure tightening and to have a desired mold surface. Upper and lower molds for mold press molding 4, 5
The resin core material 2 and the skin material 3 are press-integrated into a desired shape between them, and the resin material is supplied through the injection molding machine 6 connected to the lower mold 5.

At this time, as the skin material 3, usually, a laminated sheet of a skin layer 3a having a textured surface and a heat-laminated foam layer 3b on the back surface of the skin layer 3a is used. 3a has a thickness of 0.6 mm, and the foam layer 3b has a thickness of 3.0 mm. By molding and press-molding a material, the foam layer 3b has a thickness of 1.5 mm in the general portion and 0.5 mm in the thin portion such as a corner portion. Molded.

[0006]

As described above, when the skin material 3 having the foam layer 3b and the resin core material 2 are mold press molded by the conventional mold press molding method, the foam layer 3b is formed at the time of mold press molding. However, it has been pointed out that the resin core material 2 is easily damaged, the surface of the product becomes uneven, and the foam layer 3b does not have an appropriate thickness, resulting in deterioration of cushioning performance.

The reason for this is that when the temperature of the supplied molten resin is low, the fluidity of the molten resin decreases,
The skin material 3 tends to be damaged, and conversely, when the resin temperature of the molten resin is high, the fluidity is improved, but the foaming layer 3b is melted by the resin heat and the skin material 3 is damaged. Will receive.

In particular, this tendency can be seen in a portion where the clearance between the upper and lower dies 4 and 5 is narrow (for example, indicated by reference numeral A in FIG. 14).

The present invention has been made in view of such circumstances, and when a resin core material and a skin material are integrally formed by mold press molding of a skin material having a foam layer, unevenness or the like is formed on the surface of the skin material. It is an object of the present invention to provide a method of manufacturing an interior part for an automobile, which is capable of ensuring a sufficient thickness of a skin material without causing a defective appearance.

[0010]

In order to achieve the above object, the present invention provides a molten resin distributed and supplied to a mold surface of a lower mold for mold press molding through an injection molding machine, and a skin material is set in advance. In the method for manufacturing an automobile interior part, wherein the upper die for mold press molding is engaged with a lower die, and a resin core material and a skin material are integrally press-molded into a required shape, wherein the skin material is foamed. An unfoamed product containing the agent is supplied into the upper and lower molds, and at the time of mold press molding, the resin heat of the molten resin injected and filled into the upper and lower molds causes the foaming reaction of the skin material so that the skin material has a predetermined thickness. It is characterized by reaching.

As the skin material, a laminated sheet obtained by laminating a skin layer and a foam layer may be used, or a single sheet having foamability may be used. In particular, the surface layer is preferably a thermoplastic olefin, and the foam layer is preferably a thermoplastic olefin mixed with a foaming agent such as azodicarbonamide.

The expansion ratio of the skin material is 1.5 to 3.0.
If the expansion ratio is less than 1.5 times, the surface feel deteriorates, and if the expansion ratio exceeds 3.0 times, the foam cells become non-uniform and voids are generated. And surface irregularities are likely to occur.

Further, the clearance between the upper and lower molds for mold press molding is once lowered to the lower limit position of the upper mold, and then the upper mold is slightly raised to ensure an increase in thickness due to the foaming reaction of the skin material.

[0014]

As apparent from the above construction, since the skin material is subjected to the foaming reaction during the mold press molding, the foam layer is not damaged during the mold press molding as in the conventional case.

Further, since the step of foaming the skin material is carried out at the time of mold press molding, the step of manufacturing the skin material can be reduced.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method for manufacturing an automobile interior part according to the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a front view showing an automobile door trim manufactured by using the method of the present invention, FIG. 2 is a sectional view showing the structure of the automobile door trim, and FIG. 3 is a mold press molding apparatus used in the method of the present invention. 4 to 7 are cross-sectional views showing the steps of the method of the present invention, FIG. 8 is a time chart showing changes in the clearance between molds of the mold press molding die used in the method of the present invention, 9 and 10 show another embodiment of the method of the present invention, and are cross-sectional views showing the step of setting the skin material and the mold press forming step.

First, the structure of an automobile door trim 10 manufactured by the method of the present invention will be briefly described with reference to FIGS.

The vehicle door trim 10 is composed of a resin core material 20 formed into a desired curved surface shape and a skin material 30 attached to the surface of the resin core material 20. Polypropylene resin mixed with an inorganic filler such as talc is molded into a complicated curved surface by the mold press molding described later. When the resin core material 20 is mold press molded, the skin material 30 is the resin core material 20. Is integrally pressed on the surface side of the.

Further, in the present embodiment, the skin material 30 is composed of a laminated sheet of a skin layer 31 having a textured surface and a foam layer 32 having a cushioning property, and the skin layer 31 is made of a thermoplastic material. The olefin resin sheet and the foam layer 32 are composed of a thermoplastic olefin resin sheet mixed with a foaming agent (azodicarbonamide).

The vehicle door trim 10 is
The surface of the skin material 30 is smooth, and the thickness of the foam layer 32 is well adjusted. By adopting the method described below, the automobile door trim 10 having an excellent surface appearance and feel can be obtained.

FIG. 3 shows a schematic structure of a mold press molding apparatus 40 used for carrying out the method of the present invention. The mold press molding apparatus 40 is a mold press molding bottom which can be engaged and clamped with each other. The mold 50, a mold press molding upper mold 60, and an injection molding machine 70 that is connected to the lower mold 50 and supplies a molten resin are roughly configured. More specifically, a lower mold 50 is provided with a manifold 51, a hot runner 52 serving as a flow path for molten resin is provided in the manifold 51, and a plurality of gates 53 branched from the hot runner 52 are set. Has been done.

Next, the injection molding machine 70 is connected to a hopper 71 for supplying a resin material in pellet form, an in-line screw 72 incorporated therein, and a lower mold 50,
A nozzle 73 for supplying the molten resin is provided, and a predetermined amount of the molten resin material is pushed out to the hot runner 52 and the gate 53 of the lower mold 50 by the forward movement of the inline screw 72.

Next, each step of the method of the present invention will be described with reference to FIGS. First, as shown in FIG. 4, on the set pin 61 of the mold press molding 60,
Temporarily set the skin material 30. At this time, the skin material 30
Sets the skin layer 31 on the upper side and the foam layer 32 on the lower side.
It may be supplied in a mold of 0,60.

Further, the foaming layer 32 is mixed with a foaming agent such as azodicarbonamide, but since it is in an unfoamed state, the thickness t ₁ of the foaming layer 32 is 1.5 mm.

After that, as shown in FIG. 5, when the upper mold 60 is lowered and the clearance between the upper and lower molds 50, 60 reaches a predetermined position, it passes through the injection molding machine 70, the hot runner 52, and the gate 53. The molten resin M is distributed and supplied onto the mold surface of the lower mold 50. Even in the step of supplying the molten resin M, the upper mold 60 is moving downward, as shown in FIG.
The upper mold 60 descends to the lower limit position shown in.

At this position, press molding is carried out for 1 to 2 seconds to mold the molten resin M to mold the resin core material 20 having a desired curved surface shape, and to cover the surface of the resin core material 20 with a skin. The material 30 is integrated.

At this time, the foam layer 32 of the skin material 30
Since the foaming agent is mixed inside, the skin layer 32 starts the foaming reaction by the resin heat (200 ± 10 ° C.) of the molten resin M.

Then, the skin layer 3 in this skin material 30
In response to the foaming reaction of No. 2, the upper mold 60 moves up by a predetermined stroke and stops at the position shown in FIG. The upward movement of the upper mold 60 corresponds to the increase in the thickness of the foam layer 32 due to the foaming reaction of the foam layer 32.

Finally, the thickness t _{2 of the} skin layer 32 is
Is adjusted to 2.25 to 4.5 mm.

The expansion ratio at this time is 1.5 to 3
It may be set appropriately during the doubling. When the expansion ratio of the skin layer 32 is less than 1.5 times, the surface feel is poor, and when the expansion ratio of the skin layer 32 exceeds 3 times, there are defects such as voids due to cell roughness. .

FIG. 8 is a time chart of the clearance between the upper and lower dies 50 and 60 during mold press molding. (A) shows the start of injection, (b) shows the end of injection, and (c) shows the start of pressing. d) end of press, start of foaming reaction, (e)
Indicates the start of rising of the upper mold in consideration of the thickness of the foam layer.

As described above, according to the method of the present invention, the foaming agent is mixed in the foaming layer 32 of the skin material 30, and the foaming reaction of the foaming layer 32 is simultaneously performed by the resin heat of the molten resin M during mold press molding. Therefore, unlike the conventional case, the foam layer is not damaged by the molten resin at the time of mold press molding, and the automobile door trim 10 having a good product surface appearance and surface feel can be mass-produced.

Also in the process of forming the skin material 30,
Since the conventional foaming process can be eliminated, there is an advantage that the number of processes can be reduced.

Then, as shown in FIGS. 9 and 10, a foaming agent-containing thermoplastic olefin resin sheet 33 alone may be used as the skin material 30.

In the case of the present embodiment, the thermoplastic resin olefin resin sheet 3 with a foaming agent whose surface is textured
3 (thickness t ₁ 1.8 mm) as shown in FIG.
10, the mold press molding is performed to cause the foaming reaction of the foaming agent-containing thermoplastic olefin resin sheet 33 by the resin heat of the molten resin M, so that the final thickness t ₂ becomes 2.8
The foaming reaction proceeds so that it becomes mm.

Also in this embodiment, since the foaming reaction of the skin material 30 is performed by the resin heat of the molten resin M at the time of mold press molding, there is no damage or thermal damage to the foamed layer as in the conventional case. At the same time that an interior part having a good surface appearance and surface feel can be obtained, according to the present embodiment, since the skin material 30 uses the single sheet 33, the sheet is simply calendered and textured.
There is an additional effect that the number of sheet forming steps can be further reduced, contributing to cost reduction and weight reduction.

[0038]

As described above, the present invention has the following special operational effects.

(1) In a method of manufacturing an automobile interior part in which a resin core material and a skin material are integrated by mold press molding, an unfoamed skin material is covered by a resin heat of a molten resin during mold press molding. Since the material is foamed, the foam layer of the skin material is not damaged or thermally damaged during mold press molding as in the past, and defects such as patters and irregularities occur on the surface. Since there is no such problem and the appropriate thickness of the skin material is guaranteed, there is an effect that it is possible to mass-produce automobile interior parts having good surface appearance and surface feel.

(2) According to the method of the present invention, at the time of mold press molding of the resin core material and the skin material, the skin material is foamed by the resin heat of the molten resin, so that the man-hour for molding the skin material is reduced. Therefore, the manufacturing cost of the skin material can be reduced, and a large cost reduction of the product can be expected.

[Brief description of drawings]

FIG. 1 is a front view showing an automobile door trim manufactured by the method of the present invention.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is an overall view showing a configuration of an embodiment of a mold press molding apparatus used in the method of the present invention.

FIG. 4 is a cross-sectional view showing one step of the method of the present invention, showing the step of setting the skin material.

FIG. 5 is a cross-sectional view showing one step of the method of the present invention, showing a step of supplying molten resin.

FIG. 6 is a cross-sectional view showing one step of the method of the present invention, showing a mold press molding step.

FIG. 7 is a cross-sectional view showing one step of the method of the present invention and showing a foaming step of the skin material.

FIG. 8 is a time chart diagram of clearance between upper and lower molds in the method of the present invention.

FIG. 9 is a sectional view showing a set state of another embodiment of the skin material used in the method of the present invention.

FIG. 10 is a cross-sectional view showing a mold press molding process using a skin material of another example.

FIG. 11 is a front view showing a conventional automobile door trim.

12 is a sectional view taken along line XII-XII in FIG.

FIG. 13 is an explanatory diagram showing the overall configuration of a conventional mold press molding apparatus.

FIG. 14 is an explanatory view showing defects in the conventional mold press molding process.

[Explanation of symbols]

 10 Automotive Door Trim 20 Resin Core Material 30 Skin Material 31 Skin Layer 32 Foam Layer 33 Single Sheet 40 Mold Press Molding Device 50 Mold Press Molding Lower Mold 52 Hot Runner 53 Gate 60 Mold Press Molding Upper Mold 61 Set Pin 70 Injection Molding Machine 73 nozzle

Claims (5)

[Claims] 1. A molten resin (M) is applied onto a mold surface of a lower mold (50) for mold press molding through an injection molding machine (70).
Is distributed and supplied, and the upper die (60) for mold press molding in which the skin material (30) is set in advance is engaged with the lower die (50) to form the resin core material (20) and the skin material (30). In the method for manufacturing an automobile interior part, which is integrally press-molded into a required shape, the skin material (30) is supplied in an unfoamed state in which a foaming agent is mixed into the upper and lower molds (50, 60). During the molding press molding, the skin material (30) is generated by the resin heat of the molten resin (M) injected and filled in the upper and lower molds (50, 60).
To cause a skin material (30) to reach a predetermined thickness. 2. The skin material (30) is composed of a skin layer (31) made of a thermoplastic olefin resin and a thermoplastic olefin resin (32) containing a foaming agent. Manufacturing method of automobile interior parts. 3. The method for manufacturing an automobile interior part according to claim 1, wherein the skin material (30) is composed of a single thermoplastic plastic olefin resin sheet (33) containing a foaming agent. 4. The expansion ratio of the skin material (30) is 1.5 to.
It is set to 3.0 times.
3. The method for producing an automobile interior part according to 3. 5. During mold press molding, after the upper mold (60) reaches the lower limit position, the upper mold (60) is predetermined as the thickness of the skin (30) increases due to the foaming reaction of the skin (30). The clearance is increased, and the clearance is increased.
The manufacturing method of the interior parts for vehicles of Claim 4.