JP3134252B2 - Mold structure used for manufacturing multilayer molded products - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold structure for producing a multilayer molded product comprising a skin material in which only a predetermined portion of a surface of a thermoplastic resin is coated with a skin material and a thermoplastic resin alone. .

[0002]

2. Description of the Related Art A multilayer molded product of a skin material in which only a predetermined portion of the surface is covered with a skin material and a plain thermoplastic resin is used for interior parts such as door trims and rear trims of automobiles. To manufacture such a multilayer molded product, a thermoplastic resin is preliminarily molded by injection molding or the like, and a skin material having a predetermined shape is adhered to the molded product using an adhesive or the like, or the skin material is hardened in advance. There is a method of manufacturing a part attached to a board or the like, and attaching this part to the molded product using a screw or the like. However, such a method requires a post-process, is time-consuming, and is costly. It was a factor of up.

In order to improve the production of such a multilayer molded product, there has been proposed, for example, one described in Japanese Patent Application Laid-Open No. 64-26414.

According to this, a skin material and a molten resin are supplied between an unclosed upper and lower mold for molding, and upper and lower molds are closed to produce a multilayer molded product composed of the skin material and a thermoplastic resin. In doing so, the skin material cut into a predetermined shape is placed at a predetermined position on the upper or lower mold, and the welding resin is supplied to a substantially central portion on the back side of the skin material, so that only the predetermined portion is made of the skin material. The purpose is to obtain a multilayer molded product of the coated skin material and the thermoplastic resin alone.

[0005]

In the production of a multilayer molded article as described above, the skin material is cut into a predetermined shape in advance so that the skin material covers a predetermined position of the thermoplastic resin. It is necessary to supply the molten resin and perform the molding after the positioning at the predetermined position. For this reason, the mold structure used in the production of the above-mentioned multilayer molded product is as shown in FIGS. 7 to 9. A small convex wall 5 is formed on the cavity surface of the upper mold 1 at a position corresponding to a parting line where the skin material 3 covers the plain thermoplastic resin 4. On the cavity surface of the lower mold 2 corresponding to the small convex wall 5, a piece 7 having a wood groove (recessed groove) 6 is provided, and further, the lower mold 2 is provided with two pins 8. The pins 8 and the pieces 7 are slidable in the vertical direction of the lower mold 2.
The lower mold 2 is provided with a resin passage and a supply port (not shown).

[0006]

[0007] When a multilayer molded article is manufactured, the following steps are performed.

The skin material 3 cut to a predetermined size is placed along the concave groove 6 of the lower mold 2 with its surface side facing up (the state shown in FIG. 7).

Next, an elevating mechanism (not shown) of the mold clamping device.
Is operated to lower the upper mold 1 and temporarily stop with a certain mold clearance between the upper mold 1 and the lower mold 2 in order to form a cavity with the lower mold 2. At the stop position, the two pins 8 are moved upward to lift the skin material 3 (the state shown in FIG. 8), and lightly contact a predetermined position on the upper mold cavity surface.

In this state, the supply of the molten resin 4a to the back side of the skin material 3 is started by a molten resin supply device (not shown) such as an extruder through a resin passage provided in the lower mold. The pin 8 and the piece 7 are retracted into the lower mold 2 within a predetermined time after the start.

Thereafter, the upper mold 1 is further lowered to spread the molten resin 4a into the cavity while pressing the skin material 3, so that the skin material 3 and the thermoplastic resin plain 4 are integrally formed to form. This is completed (the state shown in FIG. 9).

Next, after cooling, the upper mold 1 is raised, the upper and lower molds 1 and 2 are opened, and the formed multilayer molded article 1 is formed.
Take out 0.

However, the multilayer molded article 10 has a structure in which a part of the surface of the thermoplastic resin 4 is covered with the skin material 2, and the skin material 2 is made of the thermoplastic resin 4. Since it is stretched to decorate the surface, it needs to be stretched at a predetermined position. However, when the skin material 3 is placed on the blank-shaped portion 2a of the lower mold 2 during molding, Since the skin material 3 has been positioned simply by being placed on the piece 7 with the wood grain groove 6 as a reference, it is very difficult for a worker having a high degree of skill to place the skin material 3 at a predetermined position. In some cases, the displacement may occur, and during molding, the displacement may also occur due to the movement of the upper mold 1 or the molten resin 4a.

In order to prevent such a case, the outer peripheral end wall 3a of the skin material 3 is set as a set line, and the outer peripheral end wall 3a is brought into contact with the outer peripheral wall 6a of the groove 6 in the lower mold 2. In this case, it is conceivable that the cavity is formed by the upper mold 1 and the lower mold 2, and is separated by the outer peripheral wall of the front end of the skin material 3. A new problem arises in that it cannot be supplied uniformly.

In view of such circumstances, the present invention is directed to a multilayer molded product in which a skin material is reliably positioned in a mold and a molten resin is uniformly supplied into a cavity. The purpose of the present invention is to provide a mold structure for manufacturing the same.

[0016]

In order to achieve the above object, a mold structure of the present invention according to claim 1 is provided in a predetermined position on a lower mold in a mold composed of an upper mold and a lower mold. One or a plurality of skin materials cut into a predetermined shape are placed, and a molten resin is supplied from the back surface side of the skin material, so that a part of the resin plain surface formed by the molten resin is covered with the skin material. In the mold structure used for the production of a multilayer molded product in which the plain resin is exposed as it is, the other portion is located at a position corresponding to the grained portion of the skin material in the plain resin in the lower mold. A plurality of projections are intermittently formed on the outer peripheral wall side of the concave groove, and a set line side wall of the skin material is brought into contact with at least a part of the protrusion to form a skin. It is characterized in that the material is positioned.

The mold structure of the present invention according to claim 2 is
Of the upper and lower molds, one or a plurality of skin materials cut into a predetermined shape are placed at predetermined positions on the lower mold, and molten resin is applied from the back surface side of the skin material. By supplying, a part of the resin plain surface formed by the molten resin is covered with a skin material, and the other part is a mold structure used for manufacturing a multilayer molded product in which the resin plain is exposed as it is. In the lower mold, a concave groove is formed at a position corresponding to a grained portion of the skin material in the resin plain, and a blank-shaped blank portion surrounded by the concave groove is formed into a cavity of the lower mold. The outer peripheral wall of the concave groove is protruded from the inner peripheral wall toward the upper mold side so as to form a projection.

Therefore, a plurality of protrusions or protrusions formed on the outer peripheral wall of the concave groove contact the set line side wall of the skin material, and are reliably positioned on the mold. Since the outer peripheral wall of the groove is formed intermittently, a space is formed between the set line side wall of the skin material and the outer peripheral wall of the concave groove, so that the flow of the molten resin in the cavity is not hindered. Thus, the molten resin is uniformly supplied to the entire inside of the cavity.

In the multilayer molded article formed by the mold structure of the present invention, a plurality of thin portions are intermittently formed on the groove wall of the wood grain groove of the resin alone. The thin portion of the groove wall of the simple grained groove serves as a starting point of stress concentration against impact.

It is conceivable that the plain resin portion is made of polyethylene, polystyrene, polyvinyl chloride, polyamide, polypropylene or the like.

The skin material is cloth, PVC sheet, foamed P
In order to use a VC sheet, a polyethylene foam sheet, a non-woven fabric, etc., and to improve the soft feeling, a two-layer structure composed of cloth + compressed urethane, cloth + polyethylene foam, polyethylene foam + PVC sheet, or cloth + urethane + 3 consisting of nonwoven fabric (backside treatment) or cloth + urethane + TPO sheet (backside treatment)
It is also conceivable that a layer configuration is used.

The molten resin is supplied from the back side of the skin material,
When molding a multilayer molded product in which the skin material and the resin material are integrally formed by the upper and lower molds, the upper mold is lowered with respect to the lower mold, and the mold clearance of the upper and lower molds becomes a predetermined width. , The upper mold is stopped once, molten resin is injected into the back side of the skin material, and after the fixed amount of injection is completed, the upper mold is lowered again to the mold clearance = 0, and the multilayer It is molded into a molded product. And the mold clearance of the upper and lower molds at which the upper mold temporarily stops is usually 15 mm to 2 mm.
Is optimal, and the lowering speed when lowering the upper mold once after stopping is in the range of 4 to 12 mm / sec, and the optimal value is 4 / sec.
mm.

As a countermeasure against damage to the skin material of the molding ground, the temperature of the molten resin is usually good at around 190 degrees Celsius, and the temperature of the preheated mold is optimally in the range of 30 to 70 degrees Celsius.

[0024]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows an automobile door trim 11 which is a multilayer molded product to be manufactured by the mold structure of the present invention.
It is a perspective view of. The door trim 11 includes an armrest portion 12, a pocket portion 13, or a speaker grill attachment portion 1.
4 and the like, and a base material 15 which is a thermoplastic resin alone.
And a skin material 16 stretched so as to cover a part of the base material 15 as an insulated skin material for the purpose of decoration or the like.

The substrate 15 is made of polyethylene, polystyrene, polyvinyl chloride, polyamide, polypropylene or the like.

As the skin material 16, a cloth, a PVC sheet, a foamed PVC sheet, a polyethylene foam sheet, a non-woven fabric, or the like is used.
3 layers composed of compressed urethane, cloth + polyethylene foam, polyethylene foam + PVC sheet, etc., or cloth + urethane + non-woven fabric (backside treatment) or cloth + urethane + TPO sheet (backside treatment)
A layered structure may be used.

The skin material 16 has a substantially quadrilateral shape, and the entire periphery of the outer peripheral edge is cut into the wood cut groove 17 of the base material 15.

In the present embodiment, the door trim 11 configured as described above is manufactured by a mold structure shown in FIG.

That is, as shown in FIG. 2, the mold structure is composed of an upper mold 21 and a lower mold 22, and the cavity trimming surface 21a of the upper mold 21 is In order to form the outer shape, a large concave portion 23 is formed, and an annular small protrusion 24 is formed at a substantially central portion of the large concave portion 23 so as to protrude toward the lower mold 22. Similarly, a large convex portion 25 is formed on the cavity forming surface 22a of the lower mold 22 so as to form the outer shape of the door trim 11 together with the large concave portion 23. The large convex portion 25 has the small convex portion. 24, the concave groove 26 is formed in an annular shape.

As shown in FIG. 3, the recessed groove 26 has a plurality of projections 29 intermittently formed on the outer peripheral wall 27 side thereof at a predetermined distance from the inner peripheral wall 28 side.

The projection 29 is provided on the inner peripheral wall 2.
When the skin material 16 is placed as a mid-skin material on the mid-strip blank shape portion 30 surrounded by the inner surface 8, the positioning member serves as a positioning member for the skin material 16.

That is, the skin material 16 has, for example, a substantially rectangular shape, and the side walls 31 to 34 of the four sides abut on all the projections 29 to position the skin material 16. In order to absorb an error or the like in the cut size of the skin material 16, for example, two side walls 31 and 32 intersecting each other are used.
Are set as the set line side walls of the skin material 16 and are brought into contact with the projections 29 facing the set line side walls to position the skin material 16 (see FIG. 4).

Further, as shown in FIG. 5, the intermediate joint blank-shaped portion 30 is formed on the general cavity forming surface 3 of the lower mold 22.
5, the outer peripheral wall 27 of the concave groove 26 protrudes 36 from the inner peripheral wall 28 toward the upper mold 22 with a step A provided. As a result, the inscribed blank-shaped part 30 is surrounded by the protruding part 36, and the setting property of the skin material 16 is improved.

When the door trim 11 is manufactured by using the thus-configured mold structure, the upper mold 21 is first opened (not closed) with respect to the lower mold 22 as shown in FIG. In this state, the skin material 16 formed by cutting the cloth cloth or the like into a predetermined size is placed on the intermediate blank 30 of the lower mold 22. At this time, the protrusion 3 of the outer peripheral wall 27
6 ensures that the skin material 16 is guided to the intermediate blank shape part 30. Then, the set line side wall 31, of the skin material 16,
32 is brought into contact with the tip of the projection 29, and the skin material 16 is set and placed at a predetermined position of the blank-shaped portion with the middle contact.

Next, from this state, the upper mold 21 is lowered in the direction of the lower mold 22, and when the mold clearance reaches a predetermined width, the upper mold 21 is stopped once and molten resin is injected from the gate 40. I do. The optimal mold clearance C when the upper mold 21 is temporarily stopped is 15 mm to 2 mm. In addition, the temperature of the molten resin is usually set at around 190 degrees Celsius to prevent the skin material 16 from being damaged by the resin temperature, and the MI value of the molten resin is selected in the range of 80 to 120. Further, it is desirable that the upper and lower molds 21 and 22 are appropriately preheated. Usually, the temperature of the preheated mold is 30 to 100 degrees Celsius.
A range of 70 degrees is optimal.

When a fixed amount of the molten resin is charged, the charging is completed, and the upper mold 21 is lowered again to the mold clearance = 0 to close the mold, thereby filling the cavity with the molten resin. , Forming the door trim 11. At this time,
The set line side walls 31 and 32 of the skin material 16 are the other sides 3
3 and 34 are pressed into the concave groove 26 by the small protrusion 24 of the upper mold 21, and are subjected to the wood graining process into the wood grained groove 17 on the base material 15 side of the door trim 11 formed by the concave groove 26 (FIG. 6), and the appearance is improved.

Since the plurality of projections 29 are intermittently formed on the outer peripheral wall 27 of the concave groove 26, the surface material 1
6 is formed between the set line side walls 31 and 32 and the outer peripheral wall 27 of the concave groove 26 so that the molten resin is uniformly supplied to the entire cavity without obstructing the flow of the molten resin in the cavity. Will be done.

After the molds are closed, the upper and lower molds 21 and 22 undergo a cooling process for a certain period of time as they are, and then again the upper mold 21.
And the solidified door trim 11 is taken out of the cavity, and the molding step is completed.

The door trim 11 thus formed is
As shown in FIG. 6, the protrusions 2 of the lower mold 22 are provided outside the wood groove 17 of the base material 15 (the exposed portion on the back side of the base material 15).
9, a recess 38 is formed, and the wood grain groove wall 17a is formed.
The thin portion 39 exists.

The thin portion 39 serves as a starting point of stress concentration and exhibits an effect of absorbing a shock due to a side collision of an automobile.

[0042]

As described above, according to the present invention, a plurality of projections or protrusions formed on the outer peripheral wall of the groove forming the wood grain groove contact the set line side wall of the skin material. , The skin material is reliably positioned on the mold, and the setability of the skin material can be improved,
In addition, since no special device is used for improving the setability, the cost of the mold can be reduced.

Further, since the projection is formed intermittently on the outer peripheral wall of the concave groove, the molten resin is uniformly supplied to the entire cavity without obstructing the flow of the molten resin in the cavity. It will be. As a result, the molded multi-layered product has a single resin portion having a predetermined thickness, thereby improving the yield rate and contributing to the cost reduction from this aspect as well.

Further, in the multilayer molded article molded by the mold structure of the present invention, a plurality of thin portions are intermittently formed on the groove wall of the resin-like wood grain groove,
As a result, the thin portion of the groove wall of the wood grain groove of the resin alone functions as a starting point of stress concentration with respect to impact.

[Brief description of the drawings]

FIG. 1 is a front perspective view of an automobile door trim formed by a mold structure of the present invention.

FIG. 2 is a sectional view showing a mold structure of a multilayer molded product according to the embodiment of the present invention.

FIG. 3 is an enlarged plan view showing the vicinity of an intermediate blank-shaped portion of the lower mold shown in FIG. 1;

FIG. 4 is an enlarged perspective view showing the inside of a circle of FIG. 3;

FIG. 5 is an enlarged cross-sectional view showing the vicinity of a middle blank portion of FIG. 2;

FIG. 6 is a cross-sectional perspective view taken along line II of FIG. 1;

FIG. 7 is a cross-sectional view showing a mold structure of a conventional multilayer molded product,
The mold opening state when the skin material is placed on the lower mold is shown.

FIG. 8 Similarly, in order to put molten resin on the back surface of the skin material,
The mold opening state when the skin material is lifted to the mold side above a predetermined position is shown.

FIG. 9 also shows a mold closed state.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Door trim (multilayer molded product) 15 Base material (resin-only part) 16 Skin material 17 Wood grain groove 21 Upper die 22 Lower die 26 Concave groove 27 Outer peripheral wall 28 Inner peripheral wall 29 Protrusion 30 Middle joint blank part 31, 32 set line side wall

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-8-300380 (JP, A) JP-A-10-34659 (JP, A) JP-A 8-174585 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) B29C 43/18-43/20 B29C 43/32-43/42 B29C 33/12-33/14

Claims (2)

(57) [Claims] 1. One or a plurality of skin materials cut into a predetermined shape are placed at predetermined positions on a lower die among upper and lower dies, and a back surface of the skin material is provided. By supplying the molten resin from the side, a part of the resin plain surface formed by the molten resin is covered with a skin material, and the other part is used for the production of a multilayer molded product in which the resin plain is exposed as it is. In the mold structure, in the lower mold, a concave groove is formed at a position corresponding to a grained portion of the skin material in the resin alone,
A plurality of protrusions are formed intermittently on the outer peripheral wall side of the concave groove, and the set line side wall of the skin material is brought into contact with at least a part of the protrusion to position the skin material. A mold structure used for manufacturing a multilayer molded product, characterized in that it is constituted. 2. One or a plurality of skin materials cut into a predetermined shape are placed at predetermined positions on a lower die among upper and lower dies, and a back surface of the skin material is provided. By supplying the molten resin from the side, a part of the resin plain surface formed by the molten resin is covered with a skin material, and the other part is used for the production of a multilayer molded product in which the resin plain is exposed as it is. In the mold structure, in the lower mold, a concave groove is formed at a position corresponding to a grained portion of the skin material in the resin alone,
By providing a step between the cavity forming surface of the lower mold and the outer peripheral wall of the concave groove so that the outer peripheral wall of the concave groove protrudes toward the upper mold side from the inner peripheral wall, by forming the middle joint blank portion surrounded by the concave groove. A mold structure used for manufacturing a multilayer molded product, wherein a protrusion is formed. [0001]