KR100548876B1 - In-mold forming process and the form structure - Google Patents

Abstract

When plasticizing the resin in the molding cylinder in the in-mold molding process, the present invention uses a method of kneading the resin with a supercritical fluid (using nitrogen or carbon dioxide gas) to reduce the viscosity of the synthetic resin up to about half, but must be fused with the resin. Melting injected through the gate by forming a coating layer made of a mesh type backcross or PP, PS, PE, etc. on the outer skin material so that the backcross or coating layer first comes into contact with the high-temperature and high-pressure resin injected into the gate. Not only can the pressure and heat of the resin be blocked first in the backcross or coating layer to prevent the skin from melting, but also the skin is deformed by being pressed by the injection pressure of the resin, thereby preventing the cushion from being lost. The present invention relates to an in-mold molding method and a molded article thereof, and the present invention relates to a backcross or Forming a coating layer by heat-sealing the membrane film or resin coating; inserting a skin material having the backcross or coating layer into the mold and vacuum-sucking; and supercritical fluid kneading into the mold to which the skin material is adsorbed. By injecting the resin at a low pressure through the gate decompression structure is an invention that enables the mass production of the in-mold molding method by the step of integral injection molding without pressing or heat deformation phenomenon on the skin material and the skin material of the gate portion.

Skin material, coating layer, in mold, molding method, molding

Description

In-mold forming process and the form             

1 is an enlarged longitudinal sectional view showing the main part of a molding according to the present invention;

Figure 2 is an enlarged longitudinal cross-sectional view showing a conventional molding.

Explanation of symbols on the main parts of the drawings

10: skin material 11: backcross or coating layer

20: molding 21: gate portion

22: space

The present invention relates to an in-mold molding method for molding a soft skin material to be integrally attached to the surface of the molded product, and a molded product thereof.

In particular, when injecting a synthetic resin product and forming the skin material integrally on the surface thereof, the synthetic resin is formed by forming a coating layer made of a mesh type backcross or PP, PS, PE, etc. on the surface material. It relates to an in-mold molding method and its molding to prevent the cushioning is reduced while the skin material around the inlet is melted and thinned due to the heat and pressure to inject.

In general, when assembling synthetic resin products such as automobile interior materials, soft skin materials are attached to the surface of synthetic resin products to prevent the exposure of synthetic resin products and to enhance the atmosphere inside the automobile. .

Conventional methods for molding interior materials, such as automobiles provided with the skin material, are divided into high pressure molding and low pressure molding.

First, the conventional high pressure injection molding method is to use a method of first injection molding the synthetic resin product of the required shape, and then attaching the skin material prepared on the surface of the injection molded synthetic resin product with an adhesive.

That is, the high pressure injection molding method first molded the synthetic resin product in the mold, transfers the injection-molded synthetic resin product to the skin material adhesion and trimming machine, and then vacuum-adsorbs the skin material to adhere the bond to the surface of the injection molded product. It was a method of adhering the injection molded article and the skin material by putting it on and pressing it with a high pressure press.

However, the high-pressure injection molding method as described above performs a series of processes such as plastic injection, plastic molding transfer, plastic molding and skin material completion by vacuum adsorption or bond bonding until the interior products for automobiles are completed. Due to the roughness, productivity and workability are reduced, which causes cost increase, and defects due to adhesive non-uniformity of the bond are high.

In addition, the high pressure injection molding method has a problem in that the stepped portion or the corner portion is not smooth but the foam layer thickness of these portions is thinner than the thickness of the other portions, thereby degrading the quality.

In order to solve the above problems, a low pressure injection molding method of the in-mold molding method in which the skin material is integrally fused to the surface of the synthetic resin product while injection molding the synthetic resin product has been used.

That is, in the low pressure injection molding method, when molten resin of a molding is injected from a plurality of gates in a lower mold, the upper mold is lowered, and the molten resin that is in contact with the bottom part of the skin material is pressed to form a plastic molding of a desired shape on the surface thereof. The method of attaching the skin material.

 This low pressure injection molding method has a problem in that the mold cost is high due to the complicated mold structure. Also, since a vertical special injection machine is required for low pressure injection, the cost of the injection machine is also high. There are many difficulties.

As described above, the low pressure injection method has a large number of gates, so that the gas generated during molding does not completely escape the air between the skin material and the molten resin for molding the molding, so that the skin material is convexly protruding. When the molten resins injected into a plurality of gates are not uniform and meet each other while spreading with each other, damages such as wrinkles of the skin material occur due to marks when the met portions overlap each other.

In addition, there was a problem in that the surface area of the upper part increased the skin material of the upper part, and the embossment of the skin material spreaded and disappeared, so that the appearance quality defect was easy to occur. In addition, the thickness of the foam layer on the back was thinned, which resulted in a problem of quality deterioration. In particular, in the case of many curved products, the foam layer becomes thinner in this area, and a lot of wrinkles are generated in the areas where the molten resin meets each other, causing a problem of deterioration of quality.

That is, as shown in FIG. 2, the conventional molding 52 for fusion molding the skin 51 and integrally high-pressure injection molding has a protrusion part due to the injection pressure, the transfer heat, and the like on the surface side opposite to the gate part 54. Since 53 is formed, the skin material 51 is pressed, and the skin material 51 pressed by the protrusion 53 is reduced or deformed than other parts, thereby degrading the quality of the product.

In particular, the molding 52, which is injection molded by fusion of the skin 51, is kneaded with the resin and supercritical fluid (using nitrogen or carbon dioxide gas) when plasticizing the resin of the molding 52 in the molding cylinder. Even when the injection molding method is used to reduce the viscosity of the synthetic resin by about half to the maximum, the skin material 51 is not only pressed by the injection pressure of the gate portion 54, but also melts little by little due to the transfer heat. It lowered, thereby causing a practical problem that has not yet been put to practical use.

Accordingly, an object of the present invention is to melt and inject a process to reduce the viscosity of the synthetic resin by up to about half by kneading the resin with a supercritical fluid (using nitrogen or carbon dioxide gas) when plasticizing the resin in the molding cylinder in the in-mold molding process. Use a mold equipped with a pressure-sensitive structure to release the injection pressure at the gate end where the resin comes into contact with the skin material initially placed in the cavity, but the back material, PP, PS, By forming a coating layer such as PE so that the backcross or the coating layer is in primary contact with the resin injected into the gate, the injection pressure of the resin applied through the pressure reducing structure of the gate and the heat of the molten resin are blocked from the backcross or the coating layer. It is possible to prevent the cushion material from being lost due to thermal deformation as the skin material is pressed by the injection pressure of the resin. It is to provide an in-mold molding method and its molding.

The object of the present invention is to form a coating layer by heat-sealing or thin-film coating the back cross on one side of the skin material, and inserting the skin material having the back cross or coating layer into the mold to adsorb, and the skin material is adsorbed It can be achieved by molding the in-mold molding in a step of injecting the resin kneaded in the supercritical fluid at a low pressure by injection molding the molded product fused to the back cross or the coating layer surface of the skin material.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In forming the upper and lower molds so as to inject a molding 20 having a shape required by a synthetic resin material, and integrally injection molding the skin material 10 using soft, the molding 20 and the skin material 10 The molding 20 is integrally injection molded using a material coated with a coating layer on the skin 10 or having a back cross attached thereto so that the back cross or the coating layer 11 is provided therebetween.

In this case, the skin 10 is indirectly fused to the surface of the molding 20 by the backcross or the coating layer 11 to be integrated.

In addition, in the thick portion near the gate 21, foaming occurs in the process of cooling the supercritical fluid, such as nitrogen or carbon dioxide kneaded in the synthetic resin, so that shrinkage of the thick portion does not occur, thereby reducing the appearance quality of the skin.

The present invention configured as described above allows the upper mold and the lower mold to inject the shape of the desired molding 20, and the manufactured upper mold is supplied with the skin material 10 having the backcross or coating layer 10 attached thereto. When the skin 10 is adsorbed, the lower mold is formed with a gate for injecting molten synthetic resin.

At this time, the back cross of the skin material 10 or the coating layer 11 is adsorbed to the upper mold to face the gate of the lower mold.

When plasticizing the synthetic resin in the injection cylinder while supplying the material of the upper and lower molds as described above, the resin and the supercritical fluid are kneaded to reduce the viscosity of the synthetic resin to about half by at least about half of the gate of the mold. This allows the pressure to be injected into the mold cavity to be lowered.

Since the injection pressure can be lowered by lowering the viscosity of the synthetic resin injected as described above, minimizing melting of the skin material 10 due to transfer heat generated at the gate end during the injection of the synthetic resin, and also generating a high pressure ejected from the gate. Due to this it is possible to block the damage to the skin material 10, it is also possible to minimize the pressing of the skin material 10 by the high injection pressure.

In addition, since the resin injected in a state in which the deformation of the skin material 10 is minimized due to the injection pressure of the resin is cooled, the skin material 10 and the molded product 20 are integrated, so that the skin material 10 and the molded product 20 are integrated. ), There is no fear of poor adhesion.

In particular, the present invention is to reduce the injection pressure of the resin as described above is injected into the molten synthetic resin is injected backcloth or coating layer 11 attached and coated on the skin material 10 without being directly in contact with the skin material (10) ).

Therefore, the back cross or the coating layer 11 prevents the heat and pressure of the molten synthetic resin from being transferred to the skin 10 so that the skin 10 can be prevented from melting due to the heat and pressure of the synthetic resin. Thermal deformation of the 10 can also be prevented to prevent the cushion of the skin 10 from being weakened.

In addition, as described above, the backcross or coating layer 11 attached and coated on the skin material 10 is slightly melted when the injection time of the molten synthetic resin through the gate is long, but this means that the skin material 10 is melted. The skin material 10 is protected without melting or pressing because it proceeds for a sufficient time to prevent.

In this case, the coating layer 11 coated on the skin material 10 may be improved in adhesion with the molded product 20 by coating with the same resin material as the material of the molded product 20. The fusion of the molding 20 is indirect fusion by the coating layer 11 but can achieve a stable fusion.

On the other hand, the molding 20 having the skin material 10 formed as described above may cause a phenomenon that the coating layer 11 at the gate portion 21 is slightly melted or pressed, but a part of the coating layer 11 may be When the change in the thickness of the molding 20 occurs due to melting or pressing, a portion formed thicker than the other portion causes a contraction action, but the supercritical fluid grows into bubbles at the portion where the contraction pressure is applied during the cooling process, and naturally gathers. Since the one or more spaces 22 are formed, shrinkage deformation of the molding 20 may also be prevented.

As described above, the present invention uses a method of kneading the resin and the supercritical fluid when plasticizing the resin in the molding cylinder in the in-mold molding process to reduce the viscosity of the synthetic resin up to about half, but to be fused with the resin. By forming a backcross or coating layer on the back contact, the backcross or coating layer is brought into contact with the resin injected into the gate, thereby lowering the injection pressure of the resin through the gate. Not only can it be prevented, thereby the effect is provided that the skin material is pressed by the injection pressure of the resin and the heat deformation to prevent the cushion is lost.

Claims (6)

In the in-mold molding method in which the molded product and the skin material are integrally injection molded using a method of reducing the viscosity of the synthetic resin by kneading the resin and the supercritical fluid when plasticizing the resin in the molding cylinder, Forming a coating layer by coating a thin film on one side of the skin material; Inserting a skin material having the coating layer into a mold and adsorbing it; Injecting a super-critical fluid kneaded resin into the mold adsorbed to the skin material at a low pressure to fusion molding on the surface of the coating layer of the skin material injection molding method characterized in that the molding. In the in-mold molding method in which the molded product and the skin material are integrally injection molded using a method of reducing the viscosity of the synthetic resin by kneading the resin and the supercritical fluid when plasticizing the resin in the molding cylinder, Attaching and forming a back cross on one side of the skin material; Inserting the skin material having the back cross into the mold and adsorbing it; Injecting a supercritical fluid kneaded resin into the mold adsorbed to the skin material at a low pressure to fusion molding on the back cross surface of the skin material injection molding method comprising the. In the in-mold molding method of integrally injection molding a molded product and a skin material which use a method of reducing the viscosity of a synthetic resin by kneading the resin and a supercritical fluid when plasticizing the resin in the molding cylinder, Inserting a skin material coated with a thin film on one side into a mold and absorbing it; Injecting a super-critical fluid kneaded resin into the mold adsorbed to the skin material at a low pressure to fusion molding on the surface of the coating layer of the skin material injection molding method characterized in that the molding. In the in-mold molding method of integrally injection molding a molded product and a skin material which use a method of reducing the viscosity of a synthetic resin by kneading the resin and a supercritical fluid when plasticizing the resin in the molding cylinder, Inserting a skin material having a back cross attached to one side into a mold and adsorbing it; Injecting a supercritical fluid kneaded resin into the mold adsorbed to the skin material at a low pressure to fusion molding on the back cross surface of the skin material injection molding method comprising the. In manufacturing the upper and lower molds so as to inject the molding 20 having the shape required by the synthetic resin material and integrally injection molding the skin material 10 using the soft material, In-mold, characterized in that the coating 20 is coated on the skin 10 so that the coating layer 11 is provided between the molding 20 and the skin 10, the injection molding integrally with the molding 20 Moldings. In manufacturing the upper and lower molds so as to inject the molding 20 having the shape required by the synthetic resin material and integrally injection molding the skin material 10 using the soft material, After the back cross is attached to one side of the skin 10 so that the back cross 11 is provided between the molding 20 and the skin 10, it is configured to be injection molded integrally with the molding 20. In-mold molding characterized in that.

Images