JPS62122715A - Integral molding of skin material and expanded plastic core material - Google Patents

Abstract

PURPOSE:To allow to produce no short shot and the like and no ruggedness on the surface of a product by a method wherein expandable plastic material is poured in a cavity formed between an top force core and a bottom force and, after that, the molds are open by lifting the upper mold core in the midway of the filling of the material by expansion in the molds and the material is hardened after the completion of expansion. CONSTITUTION:First, a skin material 3 is arranged onto the mold face of a lower mold 12. Secondly, hard urethane material 16 is poured with a RIM (reac tion injection molding) pouring machine (not shown) through a pouring gate 15 into a cavity 14 formed between an upper mold core 13 and a lower mold 12. When the cavity is nearly fully filled with the material 16, the molds are opened by slightly lifting the upper mold core 13 so as to make the cavity 14 have the thickness same as that of a product to mold. After that, due to the increase of the volume of the cavity 14, the urethane material 16 fills the cavity 14 under low blowing pressure and the reaction of the material proceeds under the state just mentioned above. Finally, the urethane material 16, the expansion of which has been completed, is hardened.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method of integrally molding a skin material and a foamed plastic core material.

(Prior Art) Products manufactured by integrating a thick inner soft sheet-like skin material and a foamed plastic core material such as hard urethane are used in console boxes and the like in the interior of automobiles.

Such a product, for example, as shown in FIG. 8, is an integrally molded product consisting of a skin material 3 whose surface layer is vinyl leather 1 and whose back layer is a foam layer 2 and a hard urethane foam core material 4, as shown in FIG. After placing the skin material 3 on the mold surface of the lower mold 6 of the mold 7 consisting of an upper mold 5 and a lower mold 6 and closing the mold 7, a predetermined amount of hard urethane material is poured into the injection gate 8. The urethane material is injected into the cavity 9, the urethane material foams and fills the cavity 9, and is then cured.

However, when attempting to mold the core material to be relatively thin using this conventional integral molding method, the cavity 9
In this case, the urethane material flowing inside the cavity 9 will be subject to large flow resistance, so the urethane material will not spread throughout the entire cavity 9 with the amount of injection required to obtain a predetermined foaming. , the density of the urethane material near gate 8 is high (and this often results in a so-called short shot. Conventionally, countermeasures to this problem include increasing the amount of urethane material injected, or applying sufficient injection pressure with a RIM injection machine, etc.) This method prevented short shots.

(Problems to be Solved by the Invention) However, if measures such as increasing the amount of material injected or applying sufficient injection pressure are used,
As shown in the figure, if there are irregularities on the back surface 10 of the skin material 3 due to the back surface pattern, material, manufacturing circumstances, etc. of the skin material 3, the irregularities may be transferred to the product surface 11, or the surface material back layer When the hardness of the foamed N2 differs locally due to variations in the foaming ratio, etc., a problem has occurred in that unevenness is formed on the product surface 11.

Therefore, the present invention aims to solve these conventional problems, and it is an object of the present invention to provide a skin that can be foam-molded without causing short shots etc. during molding and without causing unevenness on the surface of the resulting product. The object of the present invention is to provide a method for integrally molding a foamed plastic core material and a foamed plastic core material.

(Means for Solving the Problems) The method of integrally molding a skin material and a foamed plastic core material of the present invention uses a mold consisting of an upper mold core and a lower mold, and the skin material is placed on the lower mold. After the mold is placed and the mold is closed, a foamable plastic material is injected into the cavity between the upper mold core and the lower mold to perform foam molding, and at this time, the foamable plastic material foams and fills the cavity. Particularly, the integral molding method of the present invention is characterized in that the upper mold core is raised to open the mold and mold, and after foaming is completed, the plastic material is cured. This is advantageous when the wall thickness of the core material is relatively thin and the foamed plastic material flowing within the cavity is subject to significant flow resistance. To further explain this based on FIG. 4, the volume of the cavity 14 formed by the upper mold core 13 and the lower mold 12 is small and the L shown in FIG.
When the ratio of L/T to T is large, the foaming pressure of the foamable plastic material at the injection volume required for the product is too large to cause the plastic material to spread throughout the cavity. do not have. In such cases, it is very advantageous to use the method of the present invention.

In the integral molding method of the present invention, the skin material that has been conventionally used as the skin material of this type of product can be used as is. This method is particularly advantageous when the product surface is uneven due to the foaming pressure of the foamable plastic material, due to unevenness on the integrated surface or soft skin material. For example, soft skin materials such as natural leather, artificial leather such as fake leather, synthetic leather, and artificial leather, especially thick soft skin materials where the surface layer is vinyl leather and the back layer is a foam layer, especially the back surface for manufacturing reasons. The method of the present invention is suitable when a thick soft skin material having unevenness formed thereon is used as the skin material.

In addition, as the foamable plastic material, materials such as foamed polystyrene, foamed urethane, and foamed polyethylene can be used, but the bulk density can be adjusted relatively freely.
Foamable polyurethane materials are often used because they are easy to foam in-situ.

(Function) In the integral molding method of the present invention, the cavity is first made narrower than the wall thickness of the product to be molded, and the cavity is filled with foamable plastic material to the desired state using foaming pressure or injection pressure. During this process, the upper mold core is moved to open the mold. This makes it possible to keep the foaming pressure low and uniform, and at the same time ensure good fluidity by opening the mold for reaction.

That is, the method of the present invention adjusts the fluidity and foaming pressure of the foamable plastic material injected into the cavity by adjusting the thickness of the cavity, the injection pressure of the foamable plastic material, and the cavity thickness by moving the upper die core. By controlling the timing of opening the mold,
This makes it possible to mold the product in an optimal foaming state that does not cause short shots or create unevenness on the surface of the product.

For example, when a hard urethane material is used as the foamable plastic material, the urethane material filled in the cavity flows through the cavity due to foaming, and even after reaching the sealing surface between the upper mold core and the lower mold, the urethane material fills the cavity. As the reaction progresses, when the foaming pressure inside the cavity increases, the mold may be opened as described above to reduce the foaming pressure, and then the foaming pressure may be cured in this state.

(Example) An example of the method of integrally molding a skin material and a foamed plastic core material of the present invention will be described below with reference to the drawings.

In this example, an integrally molded product of a skin material (the surface layer is vinyl leather and the back layer is a foam layer) and a hard urethane foam core material used as a console box in the interior of an automobile was produced.

The molding method of this example will be explained below by dividing into each step.

As shown in FIG. 1, the skin material 3 is placed on the mold surface of the lower mold 12, and an injection gate is inserted into the cavity 14 formed by the upper mold core 13 and the lower mold 12 using an RIM injection machine (not shown). A hard urethane material 16 is injected from 15.

As shown in FIG.
The liquid flows inside and almost fills the entire cavity 14.

When the mold is completely filled, the upper mold core 13 is slightly raised as shown by arrow A in FIG. 3, and the mold is opened so that the cavity 14 has the thickness of the product to be molded.

After this, since the volume of the cavity 14 increases, the urethane material 16 fills the cavity 14 at a low foaming pressure, and the reaction proceeds in this state. Thereafter, the foamed urethane material 16 is cured. 4゜The integrally molded product of this example obtained by the above molding method was an excellent product in which the hard urethane foam core material was not short shot and the product surface 17 was not uneven. Ta.

(Effects of the Invention) According to the method of integrally molding a skin material and a foamed plastic core material of the present invention, the foaming pressure of the foamable plastic material injected into the cavity can be set to a desired pressure. Therefore, the skin material and the foamed plastic core material can be integrally molded in an optimal foaming state without causing short shots and without forming unevenness on the product surface.

Therefore, according to this molding method, it is possible to mold a product with no unevenness on the product surface even when a skin material with an uneven back surface is used or a skin material with a foam layer is used as the back layer. can.

[Brief explanation of drawings]

Fig. 1 is a process diagram of the molding method in one embodiment when hard urethane material is injected; Fig. 2 is a process diagram of the molding method in one embodiment when the hard urethane material is filled; FIG. 4 is a cross-sectional view of the mold to explain the flow resistance of the foamable plastic material injected into the cavity. FIG. 5 is a process diagram of the mold opening of the molding method in the example. Figure 6 is a cross-sectional view of the mold to explain the method. Figure 6 is a state diagram when material is injected in the conventional integral molding method. Figure 7 is a diagram showing the state when the material compresses the skin material in the conventional integral molding method. State Diagram FIG. 8 is a state diagram showing the product after demolding in the conventional integral molding method. In the figure, 3...Skin material 12...Lower mold 13...Upper mold core 14...Cavity 15...
・Injection gate 16...Hard urethane material patent applicant
Toyota Motor Corporation Same as above Toyoda Gosei Co., Ltd. Figure 1 Figure 2 1ζ Figure 3

Claims (1)

[Claims] Using a mold consisting of an upper mold core and a lower mold, a skin material is placed on the lower mold, and after the mold is closed, a foamable plastic material is placed in the cavity between the upper mold core and the lower mold. The foaming plastic material is injected and foam-molded, and at this time, the upper mold core is raised midway through the foaming and filling of the cavity to open the molding die, and after the foaming is completed, the plastic material is hardened. A method for integrally molding a skin material and a foamed plastic core material.