JPS5915073B2 - Molding method for automotive interior materials - Google Patents

Description

[Detailed Description of the Invention] The present invention provides decorative materials such as carpets, etc. The present invention relates, in part, to an improvement in a method for molding an interior part of a desired shape while backing the interior part with a thermoplastic resin.

Recently, as passenger cars have become more sophisticated, decorative materials such as carpets have come to be used on the surfaces of interior materials.

In this case, since the decorative material itself cannot provide shape retention, the manufacturing method is to attach it to a core material, or to laminate a resin sheet on the back side of the decorative material at the material stage. The material was then trimmed and then molded into the desired shape using a hot press or the like. In this case, the former method is extremely troublesome to manufacture; for example, when the material is a thick carpet, it is difficult to adhere to a complex curved surface, and it is easily peeled off.

In addition, in the latter method, a fairly thick resin sheet must be used to maintain the shape of the decorative material after molding, and a large amount of trimming waste is produced after cutting the 10 rims, which reduces product yield. Moreover, it was difficult to collect and reuse the trimming waste because different materials were bonded together. The present invention has been made in view of the above points, and consists of trimming 15 skin sheets into a product development shape, masking the unnecessary part of the back side of the skin sheet, then scattering thermoplastic resin powder, and heating this powder. To provide a method for forming an interior material for an automobile, in which the material is sintered and fixed onto a skin sheet, then cooled to the temperature conditions for press forming, and then inserted into a press mold and pressed. be.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows each device used in carrying out the present invention. These devices are, in order from the left side of the figure, a trim cutter 1 that trims the force pent into a developed product shape, a belt conveyor 2, and this conveyor 2. A press molding die 3 is provided adjacent to the terminal end of the press molding die 3.

90 The belt conveyor 2 has a net-like endless belt 4, and a hopper 5 containing thermoplastic resin powder is disposed above the starting end of the belt conveyor 2. A collection container 6 is disposed at the bottom, and the excess resin powder dropped into the collection container 6 is collected from there into the hopper 5 again via a powder pump T.

Further, on the right side of the hopper 5, and above the belt conveyor 2, a heating belt conveyor 8 is placed in order from the left side in the figure.
, and a cooling belt conveyor 9 are arranged, respectively.

Each of the conveyors 8 and 9 has a steel belt 10, and the inner bottom surface of each steel belt 10 has a heater 11,
Cooling pipes 12 are arranged, and each of these steel belts 10 makes sliding contact with the upper surface of the workpiece conveyed on the belt 4, thereby melting and gradually cooling the thermoplastic resin powder layered on the workpiece. I try to do it.

Next, a description will be given of the sequence of lining a carpet lining with thermoplastic resin powder and molding an interior part having a desired curved shape using each of the apparatuses constructed as described above.

First, the carpet 20 is trimmed with the trim cutter 1 into the shape of the product. Next, the carpet 20 is turned over so that the lining is facing upward, and set in a masking jig 21 as shown in FIG. 2 or 3.

In order to simplify the explanation, in the figure, the carpet 20 is trimmed into a rectangular shape and the masking jig 21 is used to mask the four circumferences of the carpet 20, but it is also possible to trim or mask into a more complicated shape. Is possible. In addition, the need for masking parts around the four peripheries is a problem with the appearance of this type of product, so we leave flexibility in this part so that the four peripheries can be folded back and the joints between the carpet and other parts can be fitted in an attractive manner. This is to understand the meaning. Next, with the masking jig 21 set up, the carpet 20 is
When the carpet 20 is placed on the starting end of the belt conveyor 2 and the belt conveyor 2 is operated, the following processing is performed while the carpet 20 is being conveyed on the belt 4.

That is, the thermoplastic resin powder 22 is continuously dispersed from inside the hopper 5 and falls onto the lining surface of the carpet 20, and the excess resin powder 22 passes through the net of the belt 4 and falls onto the collection container 6. , from where it is collected again into the hopper 5.

The thickness of this powder has a correlation with the amount of spraying by the hopper 5 when the conveyance speed of the carpet 20 is constant, so if the thickness is to be adjusted, the diameter of the supply port of the hopper 5 may be adjusted. Next, this carpet 20 is carried into the position of the heating belt conveyor 8, but just before this carrying-in position, the masking jig 21 is removed and returned to its original position.

The elastic plastic resin powder 22 is in contact with the steel belt 10,
By heating with the heater 11, it begins to melt from the front side, and the entire piece melts while reaching the end of the conveyor 8, and is sintered and fixed on the carpet backing. Next, the carpet 20 in this molten state is carried to the cooling belt conveyor 9, and its surface is brought into contact with the steel belt 10, whereby the molten resin 22a is gradually cooled. However, the terminal temperature of the heating belt conveyor 8 is set at least to the melting pour point of the resin powder 22 or a temperature slightly higher than this to prevent the molten resin 22a from flowing and seeping onto the surface of the carpet 20 or flowing into the mask portion. In addition, the terminal temperature of the cooling belt conveyor 9 is set to an intermediate temperature between the secondary dislocation point and the melt pour point of the resin, that is, a state where gelation begins and semi-cooling occurs, whereby the molten resin 22a can be taken out without sticking to the steel belt 10, and the conditions can be exactly the same as those used for preheating during press molding.

For example, when the resin powder 22 is made of polyethylene, polypropylene, styrene resin, vinyl chloride, etc., its terminal temperature is 90 to 130°C.

Next, before the resin 22a on the carpet 20 cools down, it is immediately set on the lower mold 3a of the press molding die 3, and the upper mold 3b is engaged with the lower mold 3a, so that the softened resin is transferred to the mold. It is press-molded into a shape and then cooled and solidified to obtain a product in the desired shape. As explained above, in the method of molding an automobile interior material according to the present invention, a decorative material such as a carpet is used as a skin material, leaving an unnecessary part on the back side of the material, bagging the thermoplastic resin powder, melting it, and Since this resin is press-molded into the desired curved shape while it is still in a semi-cooled state, it is more effective than the conventional method of laminating a resin sheet on the back of a carpet and press-molding it. Therefore, the resin material to be lined can be recovered, and only the necessary parts can be lined with the resin, so the product yield is good, and the thickness of the resin can also be adjusted freely.

In addition, in this invention, the pressing process is performed continuously from the resin lining process, and by bringing the molten resin into a semi-cooled state during that process, the preheating in the press molding process is completely eliminated. Since the conditions are the same, there are advantages such as no duplication of processing of work-in-progress unlike in the conventional method.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of each device used in the present invention, FIG. 2 is a perspective view showing a carpet set in a masking jig, and FIG. 3 is a sectional view taken along the line 3--3 in FIG. 1...Trim cutter, 3...Press mold, 5...Hopper, 6...Recovery container, 8...For heating Belt conveyor, 9...
... Cooling belt conveyor, 20 ... Carpet (skin sheet), 21 ... Masking jig, 22 ... Thermoplastic resin powder, 22a ...
...Melted resin.

Claims (1)

[Claims] 1. A process of trimming the skin sheet into a product development shape, a process of partially masking the back side of this skin sheet, and a process of dispersing thermoplastic resin powder from inside the hopper and laminating it on the back side of the skin sheet excluding the mask area. , a process of recovering the excess powder into the hopper again, a process of heating the above powder to near the melting point and sintering and fixing it on the skin sheet, and a process of converting this molten resin in its final state to a secondary dislocation point and a melt pour point. A method for forming an interior material for an automobile, which comprises a step of cooling to a temperature between 1 and 2, and a step of positioning a skin sheet in a press mold while maintaining this temperature and pressing it into a desired shape.