JPS58116135A - Manufacture of synthetic resin molded item for vehicle - Google Patents

Abstract

PURPOSE:To obtain readily and inexpensively a lightweight synthetic resin molded item for vehicles that is hardly depressed and is high in safety and whose restorability is good, by blow molding a thermoplastic resin into a hollow item, and injecting a foamable resin material into said hollow item. CONSTITUTION:A thermoplastic resin is blow molded into the hollow item 2, and a foamable resin material is injected into a hollow section 13 of the hollow item 2, and is foamed to obtain the synthetic resin molded item for vehicles. In this case, it is preferable that injection and evacuation holes 5, 6 are formed when the hollow item is blow molded, preferably with the hole 5 being located at the intermediate section of an attaching surface 1b of the hollow item, and the evacuation holes 6 being located at the periphery.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a synthetic resin molded article for a vehicle.

Synthetic resin molded products are used in automobile side protector moldings, bumpers, etc.

Conventionally, synthetic resin molded products for general vehicles have been made into solid shapes by extrusion molding or injection molding, but foamed products are now being used to improve safety for pedestrians and reduce weight. There is.

Conventional foam molded products are called RI M (Reaction
Injection Molding) etc., the foam is foamed in the injection mold and a skin layer is formed on the outer surface.In order to form the skin layer on the surface, it is necessary to make the foam cells finer, so the molding In addition to the need to strictly control the conditions, there was a problem in that the formed skin layer was thin and weak against impact. It is also possible to use hollow molded products for safety and weight reduction, but blow molded products have problems such as having a concave feel, a hollow coffin, and being easily dented by compression.

This invention was made by paying attention to the conventional problems as described in L, and aims to solve the above problems by injecting a foamable resin raw material into a blow-molded product and causing it to foam.

The present invention is a method for producing a synthetic resin molded article for a vehicle, which comprises blow molding a thermoplastic resin to form a hollow molded article, injecting a foamable resin raw material into the hollow molded article, and causing the foaming. .

Hereinafter, this invention will be explained with reference to the drawings. Fig. 1 is a perspective view showing a side pro-bottom molding to be manufactured in an embodiment of the present invention, Fig. 2 is a cross-sectional view of the conventional product, and Fig. 6 is a blow-molded product used in the embodiment. FIG. 4 is a cross-sectional view of the finished product in the example, and FIG. 5 is a perspective view of the back side of the blow-molded product.

In the drawings, reference numeral 1 denotes a molding. Conventionally, it was molded into a solid shape as shown in FIG. 2, but in the present invention, it is blow molded into a hollow shape as shown in FIG. A foamed resin layer 4 is formed thereon. 1a is a decorative surface of the molding 1, and 1b is a mounting surface to the vehicle body. The blow molded product 2 is formed by blow molding a thermoplastic resin into the shape of the finished molding 1, and there is no particular restriction on the blow molding method. In the blow molded product 2, an injection hole 5 is formed in the center of the mounting surface 1b, which is the back surface, and an exhaust hole 6 is formed in the periphery. Although these holes may be formed by processing after blow molding, it is preferable to form them during blow molding.

FIGS. 6 and 7 are vertical sectional views showing a blow molding method in which hole formation is performed at the same time, and 7 is an extrusion mold provided in the head of an extruder (not shown), and 8 is this extrusion mold 7. 10 is a cavity mold and core mold for sandwiching and blow-molding the parison 8; 11 is a nozzle with a sharp tip protruding from the core mold 10; 12 is this nozzle 11; This is the air supply tube that connects to the

The molding method is as shown in Figure 6, with the mold open and the extrusion mold 7
The cross-sectional shape of the molding 1 is defined by the following: When the molding 1 reaches below the end, the cavity mold 9 and the core mold 10 are closed in the directions of arrows a and b, and the molds are clamped. Hold 8.

At this time, the die engraver 9a is the molding 1.
Extrude the green 8 so as to form the surface 1b.

During mold clamping, the movement of the core mold 10 causes the nozzle 11 to break through the side wall of Harino/8 and be inserted into the inside, and then the cavity mold 9 and the core mold 10 are completely closed.

In this state, air is supplied from the air supply tube 12 and blown into the ξ ring 8 through the nozzle 11, and as shown in FIG.

10a to form a blow molded product 2. When the air blowing starts, the cavity mold 9 and the core mold 10 are moved perpendicularly to the plane of the paper to cool them, and after assimilation, the molds are opened.
The blow molded product 2 falls automatically.

Due to the movement of the cavity mold 9 and core mold 10, the upper part of the parison 8 is torn off, further extrusion is performed, and by the time the cavity mold 9 and core mold 10 return, the next parison 8 is in the position shown in FIG. Then, repeat the above operation to perform molding.

In the blow-molded product 2 obtained as described above, the marks of the nozzle 11 remain as holes, which can be used as injection holes 5 and exhaust holes 6.

FIG. 8 is a vertical sectional view showing a state in which a foamed resin raw material is injected into a blow-molded product. As shown in FIG.
B is placed facing upward, and liquid foamed resin raw material 14 is injected from the injection nozzle 16 into the hollow part B through the injection hole 5, and foamed in the hollow part 6. The foamed resin raw material 14 is particularly limited as long as it can form the foam resin layer 4, such as a material that produces a foamed resin by reaction (for example, a mixture of polyol and incyanate), or a resin liquid containing a foaming agent. There isn't. By injecting the resin raw material 14, the air in the hollow part 6 is exhausted from the exhaust hole 6, and the resin raw material 14 is injected into the hollow part 3.
When the reaction is completed, a foamed resin layer 4 is formed as shown in FIG. The resin leaking from the exhaust hole 6 is removed after solidification, and the molding 1 as a molded product is completed.

In the explanation of L nL, the injection hole 5 does not necessarily have to be provided in the center, but if it is provided in the center, the resin raw material 14 can be evenly distributed in the hollow part 6, and the foamed resin layer 4 can be uniformly formed. can be formed. In addition, if the exhaust hole 6 is provided at the peripheral edge, it is possible to prevent air from remaining in addition to the same effect.During blow molding, it is desirable to make the nozzle 11U protrude higher than the parting part 10b of the core mold 10; If the tip is sharp and pointed, nozzle 11
can be inserted completely. Furthermore, by arranging the nozzle 11 so as to be located approximately in the center of the mounting surface 1b of the blow-molded product 2, the injection hole 5 can be formed approximately in the center, and the air of χ·1 can be uniformly supplied to the entire blow-molded product 2. It is useful for uniform molding. If the nozzles 11 are arranged not only in the center but also in the periphery, the air supply becomes more uniform.

Since the resin raw material 14 can be injected under atmospheric pressure, a simple device as shown in FIG. 8 may be used, but other means may also be used. In this case, an injection hole 5 is provided at one end of the blow molded product 2.
and an exhaust hole 6 at the other end, and the injected resin raw material 1
4 may flow approximately in one direction.

Although the above explanation has been made using side protector molding as an example, the present invention can also be applied to other synthetic resin molded products for vehicles, such as pans, bumper moldings, sill moldings, front spoilers, rear spoilers, etc. Parison according to each shape 8. Cavity type9. By changing the shape of the core mold 10 and the like, blow-molded products 2 of different shapes can be molded to obtain molded products of different shapes.

FIG. 9 is a perspective view showing a bumper manufactured according to another embodiment, FIG. 10 is a cross-sectional view thereof, FIG. 11 is a perspective view showing a front under spoiler manufactured according to another embodiment, and FIG. 12 is a perspective view thereof. FIG. 3 is a cross-sectional view, each of which was manufactured in the same manner as in the previous example.

As explained above, according to this invention, blow h
+X: Since the foamable resin raw material is injected into the shaped product and foamed, the following effects can be obtained.

(1) Since the blow-molded product is closely filled with a foamed resin layer, there is no dented or hollow feeling, and it absorbs impact force, has good restorability, and is unlikely to be dented.

(In my experience, it is highly safe for pedestrians.)

(37 Since the foamed resin layer is protected by the blow molded product, it will not be damaged by impact force, and there is no need to make the foam cells dense. Therefore, there is no need to strictly control the foaming conditions, and the foaming rate can be reduced. It can be made higher and lighter.

(4'+ Generally, molding of 2Wi with different materials requires complicated equipment and expensive molds, but in the present invention, molded products can be obtained at low cost with a simple equipment.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing a side protector molding to be manufactured in an embodiment of the present invention, Fig. 2 is a cross-sectional view of the conventional product, and Fig. 6 is a cross-sectional view of a blow-molded product used in the embodiment. 4 is a cross-sectional view of the finished product in the example, FIG. 5 is a perspective view of the back side of the blow-molded product, FIGS. 6 and 7 are vertical sectional views showing an example of the blow-molding method, and FIG. Figure 8 is a vertical cross-sectional view showing an example of a foamed resin injection method, Figure 9 is a perspective view showing a bread ξ- manufactured according to another example, Figure 10 is a cross-sectional view thereof, and Figure 11 is a separate one. FIG. 12 is a perspective view showing a front under spoiler manufactured according to the embodiment, and FIG. 12 is a cross-sectional view thereof. In each figure, the same reference numerals indicate the same or equivalent parts, 1 is the molding, 2 is the blow molded product, 6 is the hollow part, 4 is the foamed resin layer, 5 is the injection hole, 6 is the exhaust hole, 7 is the extrusion mold, 8 is a *ξ ring, 9 is a cavity type, 10 is a core type, 11 is a nozzle, 12 is an air supply tube, and 16 is an injection nozzle. Agent Patent Attorney Sei Yanagihara

Claims (1)

[Claims] II) A dual-use synthetic resin molding characterized by blow molding a thermoplastic resin to form a hollow molded product, injecting a foamable resin raw material into the hollow molded product, and causing it to foam. A method for manufacturing a synthetic resin molded article for a vehicle according to claim 1, wherein the foaming is performed while expelling air from the holes. (X()) A method for manufacturing a synthetic resin molded product for a vehicle according to claim 1 or 2, in which holes for injection or exhaust are formed during blow molding of the hollow molded product. A synthetic resin molded product for a vehicle according to any one of claims 1 to 3, which is blow-molded by blowing air through a blowing pipe protruding from a mold surface that forms a mounting surface of the hollow molded product. Manufacturing method.