JPH09141691A - Double layer molded article and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a double layer molded article consisting of a first resin layer and second resin layer integrally laminated by injection molding, further, prevent advantageously the occurrence of flashes caused by a molding shrinkage of the first resin layer. SOLUTION: The composite layer molded article 10 contains at least a first resin layer 12 and second resin layer 14 laminated integrally by injection molding, and a rib 16 is integrally projection molded in an extending manner along the end periphery of the laminated position of the second resin layer 14 on the opposite surface at the laminated side of the second resin layer 14 in the end part of the laminated position of the second resin layer 14.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a first resin layer formed by injection molding and a surface of the first resin layer,
A second resin layer integrally laminated by injection molding, and a multi-layer molded product including at least the manufacturing method thereof,
In particular, the present invention relates to a multi-layer molded product having an improved structure so that generation of burrs due to molding shrinkage of the first resin layer can be effectively prevented, and an advantageous manufacturing method thereof.

[0002]

2. Description of the Related Art Conventionally, as one type of resin molded product, there is a multi-layer molded product formed by integrally laminating a plurality of resin layers. For example, a vehicle interior part or the like is formed of a multi-layer molded product having a two-layer structure in which a skin material layer is integrally laminated on the surface of a base material layer to provide a base material layer. The resin material and the resin material forming the skin material layer are made different in color and material from each other, so that their design and functionality can be advantageously enhanced.

By the way, such a multi-layer molded article can be manufactured according to various methods. When manufacturing the vehicle interior parts having a two-layer structure as described above,
Generally, a predetermined injection molding method such as two-color injection molding has been adopted. As is well known, this two-color injection molding method uses a two-color injection molding machine including one type of rotatable fixed mold and two types of movable mold.
One of the movable dies of a variety of types and a fixed die constitute a first die, and a predetermined resin material is injected into a molding cavity formed in the first die to form a base. Forming a material layer,
Then, after opening the first mold, a second mold is formed between the fixed mold and the other of the two types of movable molds while the base material is accommodated in the fixed mold. A mold is formed, and a resin material having a different color or material from the resin material for providing the base material layer is injected into a molding cavity formed between the base material layer in the fixed mold and the other movable mold. Then, the skin material layer is integrally laminated on the surface of the base material layer to obtain the intended multi-layer molded article.

When a multi-layer molded article is obtained by a multi-color injection molding method such as such a two-color injection molding, a plurality of resin layers are advantageous without requiring a special adhesive or bonding work. In the mold for molding the plurality of resin layers respectively, the fixed mold may also be used, and the resin layers that are successively molded can be separated from the mold one by one to separate the molds. Since it is not necessary to set it in the mold, it is possible to enjoy the advantage that the molding operation of the multi-layer molded product can be performed extremely efficiently.

However, in a multi-layer molded article formed by utilizing such an injection molding method, due to the molding shrinkage of the resin layer which is unavoidably generated in the molding process,
The following problems are caused.

That is, for example, in the two-color injection molding as described above, when the skin material layer is laminated on the surface of the preformed base material layer, the base material layer is housed in the fixed mold. Only the movable mold is exchanged while it is being squeezed, and a molding cavity for molding the skin material layer is formed by the exchanged movable mold and the base material layer.
As shown in FIG. 2, the base material layer 12 housed in the fixed mold 20 is molded and contracted with cooling, so that the base material layer 12 is formed between the end edge 18 and the fixed mold 20. Layer 1
2 and the movable mold 34 for forming the skin material layer, a gap 32 is formed which is connected to the cavity 38 for forming the skin material layer. Therefore, as is clear from FIG. 9, the cavity for forming the skin material layer is formed. When a resin material 40 for forming a skin material layer that gives a skin material layer is injected into the inside 38, the resin material 40 flows into the gap 32, and as a result, a finally obtained multi-layer molded product is obtained. Give a product side,
Edge 1 of the base material layer 12 where the skin material layer 14 is laminated
8 has caused a very big problem that a burr having a shape corresponding to the gap 32 is generated.

In order to solve such a problem, in consideration of the molding shrinkage of the base material layer 12, the skin material layer of the movable mold 34 for molding the skin material layer used for molding the skin material layer 14. It is conceivable to design the shape of the molding cavity 38, but in reality, each of the base material layers 1 to be molded is formed.
Since the shrinkage amount varies depending on 2, it is almost impossible to design the shape of the skin material layer forming cavity 38 of the skin material layer forming movable mold 34 so as to be able to cope with (adapt) all of them. It is impossible.

[0008]

The present invention has been made in view of the above circumstances, and the problem to be solved is that the first resin formed by injection molding is used. A layer and a second resin layer integrally laminated on the surface of the first resin layer by injection molding to form a multi-layer molded article, in which molding shrinkage of the first resin layer It is an object of the present invention to provide a technique capable of advantageously preventing the occurrence of burrs. Further, in the present invention, it is also a problem to be solved to provide an advantageous method for producing a multi-layer molded article having such excellent characteristics.

[0009]

Then, in the present invention, in order to solve such a problem, a first resin layer formed by injection molding, and a surface of the first resin layer, A second resin layer integrally formed by injection molding,
In a multi-layer molded article including at least, at the end of the portion where the second resin layer is laminated in the first resin layer, on the surface opposite to the side where the second resin layer is laminated, The feature of the present invention is that ribs extending along the edge of the portion where the second resin layer is laminated are integrally formed so as to project.

That is, in such a multi-layer molded article according to the present invention, since the first resin layer is formed by injection molding, the first resin layer is a predetermined mold. Molding shrinkage occurs as it is molded inside and is cooled, whereby a large shrinkage force acts on the first resin layer toward the center side thereof. At the end of the portion of the layer where the second resin layer is laminated, the end of the portion where the second resin layer is laminated and which protrudes to the side opposite to the side where the second resin layer is laminated. Since the rib extending along the edge is integrally molded, the rib is interfered (engaged) with the mold in the mold, whereby the first resin layer of the first resin layer, From the ribs, the portion on the acting direction of the contracting force, in other words, the first portion In the part where the second resin layer is laminated in the fat layer, the part excluding the end part from the edge to the part where the rib is formed is the contracting force exerted on the first resin layer. Accordingly, the contraction is prevented, and only the end portion of the portion of the first resin layer where the second resin layer is laminated is contracted by the contracting force.

Therefore, in such a multi-layer molded article, the amount of shrinkage of the first resin layer due to molding shrinkage can be significantly reduced, whereby the shrinkage of the first resin layer causes The gap formed between the edge of the portion of the first resin layer where the second resin layer is laminated and the mold that forms the first resin layer can be made extremely small. As the molding of the second resin layer,
It can be advantageously avoided that the resin material for providing the second resin layer gets into the gap.

Therefore, in the multi-layer molded article according to the present invention, due to the molding shrinkage of the first resin layer, the edge of the portion where the second resin layer is laminated in the first resin layer is formed. Burrs can be very effectively prevented from occurring.

According to one of the preferred embodiments of the multi-layer molded article according to the present invention, the rib is formed at the end of the portion of the first resin layer where the second resin layer is laminated. It is formed with a height of 1 mm or more at a position within 50 mm from the edge of such a portion.

In the multi-layer molded product having such a structure, the rib is formed at a position within 50 mm from the edge of the portion of the first resin layer where the second resin layer is laminated. Therefore, in the first resin layer, the length of the part that is actually contracted can be advantageously shortened by the molding shrinkage, and the molding shrinkage inevitably forms the first resin layer. The gap between the edge of the portion where the second resin layer is laminated and the mold for molding the first resin layer can be made even smaller, and the rib height is 1 mm or more. By this, when the first resin layer is contracted by molding, the rib more reliably interferes with the mold against the contraction force exerted on the first resin layer ( Can be engaged).

Therefore, in such a multi-layer molded article, the occurrence of burrs due to the molding shrinkage of the first resin layer can be prevented even more advantageously.

In the present invention, (a) a first resin layer is formed, and a rib extending along the edge of the first resin layer is integrally formed at the end of the first resin layer. And (b) including an end portion of the first resin layer on the surface of the first resin layer opposite to the side on which the rib is provided. The second injection molding step of integrally forming the second resin layer on the upper part,
The method for producing a multi-layer molded product containing the same is also a feature thereof.

In the method for producing a multi-layer molded article according to the present invention as described above, in the first injection molding step, ribs that can advantageously reduce the shrinkage amount of the first resin layer due to molding shrinkage are provided. With respect to the first resin layer, it can be easily integrally molded, and in the second injection molding step, the second resin layer, at a predetermined site on the surface of the first resin layer,
It can be easily and surely laminated.

Therefore, according to the method for producing a multi-layer molded article according to the present invention, the multi-layer molded article having the above-mentioned excellent characteristics can be produced extremely advantageously.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, representative examples of the present invention will be described in detail with reference to the drawings in order to more specifically clarify the present invention.

First, FIGS. 1 to 3 schematically show a part of an automobile console box as an example of a multi-layer molded product having a structure according to the present invention. As is clear from those figures, the console box 10
It has a two-layer structure including a base material layer 12 as a first resin layer and a skin material layer 14 as a second resin layer. That is, in the console box 10, the thin skin material layer 14 made of a thermoplastic elastomer is integrally laminated and formed on a part of the surface of the base material layer 12 made of polypropylene resin. .

In the console box 10, in particular, unlike the conventional case, the rib 1 is provided on the surface of the base material layer 12 opposite to the surface on which the skin material layer 14 is laminated.
6 are integrally formed. More specifically, the rib 16 has a substantially thin plate shape as a whole,
At the end of the base material layer 12 where the skin material layer 14 is laminated, the base material layer 12 protrudes at a predetermined distance from the end edge 18 of the base material layer 12 and has a predetermined height.
Extends substantially parallel to the edge 18 of the. And the base material layer 1
On the surface opposite to the side on which the skin material layer 14 of 2 is laminated, the end edge 18 side portion is continuously erected so as to be separated from the other portion.

By the way, the console box 10 having such a structure is formed by integrally molding the base material layer 12 and the skin material layer 14 by injection molding. The molding operation will advantageously be carried out according to the following procedure.

That is, first, as shown in FIG. 4, the fixed layer 20 and the movable layer 22 for forming the base layer constitute a base layer forming die 24, and the base layer forming die is formed. Mold 24
A base layer molding cavity 28 corresponding to the shape of the base layer 12 to be molded and having a rib molding portion 26 for molding the rib 16 is formed therein, and,
The base material layer forming cavity 28 is filled with a base material layer forming resin material 30 which gives the base material layer 12 by injection.

Thereafter, as shown in FIG. 5, the base material layer molding resin material 30 is cooled and solidified in the base material layer molding cavity 28 of the base material layer molding die 24.
The base layer 12 is formed by integrally forming the rib 16 having a predetermined height at the end of the surface on one side in the thickness direction.

At this time, in the base material layer 12, a large shrinkage force acts in the direction of the arrow in FIG. The rib 16 provided integrally interferes with (engages with) the cavity surface of the rib forming portion 26 in the base material layer forming cavity 28, so that the rib 1 of the base material layer 12 is formed.
From 6, the side of the contracting force acting (the right side in FIG. 5)
Part, in other words, the edge 1 of the base material layer 12
The part other than the end part from 8 to the forming part of the rib 16 is prevented from being contracted in accordance with the contracting force, and the side from the rib 16 in the direction opposite to the acting direction of the contracting force ( 5, the left side portion, that is, the base material layer 12
Only the end portion from the edge 18 to the portion where the rib 16 is formed is contracted by the contracting force. As a result, as is clear from FIG. 5, the gap 32 between the end edge 18 of the base material layer 12 and the fixed die 20 is unavoidably formed along with the molding shrinkage of the base material layer 12. However, it can be made significantly smaller than the conventional one.

Next, as shown in FIG. 6, with the fixed mold 20 accommodating the base material layer 12, the fixed mold 20 and the movable mold 34 for molding the skin material form a mold for molding the skin material layer. 36, and in the skin material layer forming die 36,
A skin material layer molding cavity 38 is formed between the base material layer 12 housed in the fixed mold 20 and the skin material layer molding movable mold 34.

After that, as shown in FIG. 7, the skin material layer forming resin material 40 for providing the skin material layer 14 in the skin material layer forming cavity 38 of the skin material layer forming die 36.
Is injected and filled.

At that time, as described above, the edge 1 of the base material layer 12 is formed.
Since the gap 32 formed between the mold 8 and the fixed die 20 is extremely small, it can be advantageously prevented that the skin material layer molding resin material 40 enters the gap 32. It is like this.

Then, the skin material layer forming resin material 40 is cooled and solidified in the skin material layer forming die 36,
At the same time that the skin material layer 14 is molded, it is integrated with the base material layer 12 to obtain the console box 10 as a multi-layer molded product as shown in FIG.

As described above, in the console box 10 according to the present embodiment, at the end of the base material layer 12 where the skin material layer 14 is formed, the side where the skin material layer 14 is laminated is Since the rib 16 is integrally formed on the surface on the opposite side with the rib 16 extending substantially parallel to the edge 18 of the base material layer 12, the amount of shrinkage of the base material layer 12 due to molding shrinkage is reduced. Can be effectively reduced, and the gap 32 between the fixed mold 20 and the edge 18 of the base material layer 12 formed by the contraction of the base material layer 12 can be made significantly smaller. Therefore, when the skin material layer 14 is molded, the skin material layer forming resin material 40 that provides the skin material layer 14 can be effectively prevented from entering the gap 32, and as a result, Unlike the conventional one, this gap
It can be advantageously avoided that the skin material layer molding resin material 40 that has entered the inside 2 is solidified on the edge 18 of the base material layer 12.

Therefore, in such a console box 10, it is extremely effective that burrs are generated on the edge 20 of the base material layer 12 which gives a product surface due to the molding shrinkage of the base material layer 12. Can be prevented. Then, the console box 10 having such excellent characteristics can be obtained by adopting the manufacturing method as described above.
It will be extremely advantageous.

The representative embodiment of the present invention has been described above.
Although described in detail, this is a literal example, and the present invention should not be construed as limited to those examples.

For example, in the above embodiment, the base material layer 12 as the first resin layer was made of polypropylene resin, and the skin material layer 14 as the second resin layer was made of thermoplastic elastomer. The resin material for providing such a first resin layer and the second resin layer is not limited to this, and any of the materials conventionally used as the constituent material of the multilayer molded article is , Can be advantageously used.

Further, in the above-mentioned embodiment, the console box 10 which is a multi-layer molded product has the two-layer structure of the base material layer 12 and the skin material layer 14 as described above. The molded product may be configured by laminating two resin layers and one or more layers other than the resin, and further has a laminated structure composed of three or more resin layers. However, it doesn't matter. In the case of the multilayer molded article having a laminated structure composed of three or more resin layers, at least the first resin layer formed first is the same as the base material layer 12 in the above-mentioned embodiment. It needs to be structured.

Further, in the above-described embodiment, the rib 16 is erected at a position apart from the edge 18 by a predetermined distance at the end of the base material layer 12 where the skin material layer 14 is laminated. The rib 16 may be provided so as to integrally extend from the edge 18 of the base material layer 12,
In that case, the shrinkage of the base material layer 12 due to the molding shrinkage, especially the shrinkage occurring in the direction substantially perpendicular to the ribs 16, can be almost eliminated, and as a result, the occurrence of burrs due to the molding shrinkage can be further suppressed. It can be prevented more effectively.

Further, even when the rib 16 is erected at a position separated by a predetermined distance from the edge 18 of the portion of the base material layer 12 where the skin material layer 14 is laminated, that distance (in FIG. 3, Although not particularly limited, the dimension (m) is preferably 50 mm or less, and more preferably 20 mm, in order to advantageously reduce the shrinkage amount of the base material layer 12 due to molding shrinkage. It is the following.

Further, the height of the rib 16 (dimension indicated by h in FIG. 3) is not limited to any particular value. In order to more reliably interfere (engage) with the cavity surface of the rib forming portion 26 in the base material layer molding cavity 28 of the base material layer molding die 24 that molds the layer 12, preferably 1 mm or more. It is more preferable that the height is about 2 to 3 mm.

Furthermore, the thickness of the rib 16 (dimension indicated by w in FIG. 3) is not particularly limited, and as long as a sink mark or the like does not cause a defective appearance, a material cost or the like. In consideration of the above, it is preferable that the rib 16 has a large thickness so that the rib 16 can surely interfere (engage) with the cavity surface of the rib forming portion 26.

Further, in the above-described embodiment, the rib 16 is continuously erected at the end of the base material layer 12 where the skin material layer 14 is laminated.
Can also be formed intermittently at such a portion. However, in that case, it is necessary to determine the interval between the ribs 16 so that the merit obtained by forming the ribs 16 such that the amount of shrinkage of the base material layer 12 due to molding shrinkage can be reduced. There is.

Further, in the above-mentioned embodiment, the rib 16 is formed so as to extend substantially parallel to the edge 18 of the base material layer 12, but it is not always necessary to do so. However, since the rib 16 is formed so as to be more parallel to the edge 18, the end portion from the edge 18 to the portion where the rib 16 is formed in the base material layer 12 is formed. The contraction of the removed portion can be suppressed more effectively.

Further, in the above-mentioned embodiment, the rib 16 as a whole is formed in a substantially thin plate shape, but it goes without saying that the overall shape of the rib 16 is not limited at all. is there.

Further, in the above-mentioned embodiment, the method of using the two-color injection molding method has been illustrated as the method of obtaining the console box 10 which is a multi-layer molded product. However, other than that, the injection molding method may be used. However, any method can be adopted.

In addition, in the above-mentioned embodiments, specific examples of the present invention applied to an automobile console box and a manufacturing method thereof are shown. However, in the present invention, in addition, a plurality of resin layers are integrated by injection molding. As a matter of course, the present invention can be advantageously applied to any of a multi-layer molded article formed by stacking and forming the same and a manufacturing method thereof.

Although not listed one by one, the present invention is
Based on the knowledge of those skilled in the art, various changes, modifications, improvements and the like can be implemented in an embodiment,
It goes without saying that all such embodiments are included within the scope of the present invention, without departing from the spirit of the present invention.

[0045]

As is apparent from the above description, in the multi-layer molded article according to the present invention, the first resin layer and the second resin layer are integrally laminated by injection molding. In addition, at the end of the portion where the second resin layer is laminated in the first resin layer, the second resin layer is provided on the surface opposite to the side where the second resin layer is laminated. Since ribs extending along the edge of the laminated portion are integrally formed so as to project, the ribs form the first resin layer when the first resin layer shrinks due to molding shrinkage. The mold can be satisfactorily interfered with (engaged) with the mold, and the shrinkage amount of the first resin layer can be effectively reduced, thereby forming the shrinkage of the first resin layer. The gap between the first resin layer and the mold can advantageously be made small, and As a result, it is possible to effectively prevent the molten resin material that provides the second resin layer from entering the gap between the first resin layer and the mold during the molding of the second resin layer. It can be done.

Therefore, in the multi-layer molded article according to the present invention, due to the molding shrinkage of the first resin layer, the edge of the portion of the first resin layer where the second resin layer is laminated is formed. Burrs can be very effectively prevented.

According to the method for producing a multi-layer molded article according to the present invention, a multi-layer molded article having such excellent characteristics can be produced extremely advantageously.

[Brief description of the drawings]

FIG. 1 is a perspective explanatory view showing an example of a multi-layer molded product according to the present invention.

FIG. 2 is an enlarged explanatory view taken along arrow A in FIG.

FIG. 3 is an explanatory cross-sectional view of a main part showing an enlarged BB cross section in FIG. 2;

FIG. 4 is an explanatory view showing an example of a manufacturing process of the multi-layer molded product shown in FIG. 1, in which a molten resin material giving a first resin layer is molded in a mold for molding the first resin layer. It is shown in the state of being ejected.

5 is an explanatory view showing an example of a manufacturing process of the multi-layer molded product shown in FIG. 1, showing a state in which the molded first resin layer is cooled.

6 is an explanatory view showing an example of a manufacturing process of the multi-layer molded product shown in FIG. 1, showing a state in which a mold for molding the second resin layer is configured.

FIG. 7 is an explanatory view showing an example of a manufacturing process of the multi-layer molded product shown in FIG. 1, in which a molten resin material for giving a second resin layer is molded in a mold for molding the second resin layer. It is shown in the state of being ejected.

FIG. 8 is a diagram showing an example of a manufacturing process of a conventional multi-layer molded product.
FIG.

FIG. 9 is a view showing an example of a manufacturing process of a conventional multi-layer molded product.
FIG.

[Explanation of symbols]

10 Console Box 12 Base Material Layer 14 Skin Material Layer 16 Rib 18 End Surface 20 Fixed Mold 22 Base Material Layer Molding Movable Mold 24 Base Material Layer Molding Mold 26 Rib Molding Part 28 Base Material Layer Molding Cavity 30 Base Material Layer Molding Resin material for use 32 Gap 34 Movable mold for molding skin material layer 36 Mold for molding skin material layer 38 Cavity for molding skin material layer 40 Resin material for molding skin material layer

Claims (3)

[Claims] 1. A composite including at least a first resin layer formed by injection molding, and a second resin layer integrally laminated on the surface of the first resin layer by injection molding. In a layer molded article, at the end of the portion where the second resin layer is laminated in the first resin layer, on the surface opposite to the side where the second resin layer is laminated, A multi-layer molded product, characterized in that ribs extending along the edge of the portion where the two resin layers are laminated are integrally formed. 2. The rib has a height of 1 mm or more at a position within 50 mm from an edge of a portion of the first resin layer where the second resin layer is laminated, at an end portion of the first resin layer. The multilayer molded article according to claim 1, which is formed. 3. A first injection molding step of forming a first resin layer and integrally forming a rib extending along an edge of the first resin layer at an end portion of the first resin layer, On the surface of the first resin layer opposite to the side where the ribs are provided, the second resin layer is integrally formed at a portion including the end portion of the first resin layer where the ribs are provided. And a second injection molding step of forming a laminate.