JPH0342564B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method of pressing a thermoplastic resin impregnated with long fiber glass to form a molded article having a hinge portion.

[Background Art and its Problems] Thermoplastic resin impregnated with long fiber glass has various features such as high strength and high rigidity, and excellent chemical resistance. For this reason, it is used as a press molding material and is widely molded into automobile parts, household goods, etc. However, on the other hand, since it is impregnated with long fiber glass, it does not have the flexibility that thermoplastic resin inherently has.For this reason, conventionally, molded products with hinge parts that require flexibility have been made using long fiber glass impregnated thermoplastic resin. It could not be molded from scratch.

Therefore, the types of molded products that can be manufactured by press molding using long-fiber glass-impregnated thermoplastic resin as a material are limited to those without hinges, which limits the degree of freedom in designing the molded product and makes it difficult to design. It was inconvenient.

[Object of the Invention] An object of the present invention is to provide a press molding method that allows a molded product having a hinge portion to be obtained even when press molding is performed using a long fiber glass-impregnated thermoplastic resin as a material.

[Means and effects for solving the problems] Therefore, the structure of the present invention is to press a thermoplastic resin impregnated with long fiber glass between a pair of molds such as an upper mold and a lower mold to produce a molded product having a hinge part. A press molding method for molding the long fiber glass-impregnated thermoplastic material, wherein at least one of the pair of molds is provided with a protrusion projecting in the direction of the other mold, and the long fiber glass-impregnated thermoplastic is The resin is divided and supplied to the pair of molds, and the long fiber glass-impregnated thermoplastic resin is compressed by the pair of molds, and during this compression, the resin flows through the narrow gap formed by the protrusion. By doing so, the long fiber glass-impregnated thermoplastic resin that was supplied separately was connected and integrated, and thereby the corresponding portion of the protruding portion became thinner and became a hinge portion that could exhibit the flexibility inherent to the thermoplastic resin. It is characterized by its ability to form molded products.

[Example] FIG. 1 shows a pair of molds used in this example.

These molds, which are metal molds, consist of an upper mold 1 and a lower mold 2. The lower mold 2 has a platform-shaped convex portion 5 that bulges upward from a disk-shaped base 4, and a concave portion 3 is formed on the lower surface of the upper mold 1, and the upper mold 1 descends to protrude into this concave portion 3. Part 5
The molds are matched by fitting together. During mold matching, a cavity for supplying material is secured between the top surface 3A of the concave portion 3 and the top surface 5A of the convex portion 5, and these top surfaces 3A and 5A serve as press molding surfaces. In the illustration, these press-formed products 3A, 5
Although A is a square flat surface, the shapes of the press molding surfaces 3A and 5A are, of course, set according to the shape of the molded product to be molded.

The press molding surface 5A of the lower die 2 is provided with a protrusion 6 that protrudes toward the upper die 1. Since the protrusion 6 is for forming a hinge part in the molded product, it is not a hinge part. Correspondingly, it has a linear shape and protrudes from the press-formed product 5A. In the illustrated example, the lower mold 2
A plate-like member 7 is inserted and fixed into a vertical groove 5B formed in a convex part 5, and a linear protrusion 6 is formed by making the head 7A of this plate-like member 7 protrude from the press molding surface 5A. ing. The amount of protrusion of the protrusion 6 is determined by the distance between the tip of the protrusion 6 and the press-formed product 3A of the upper die 1 when the upper die 1 and the lower die 2 are clamped.
The size should be such that there is a narrow gap of 0.15 to 0.5 mm.

FIGS. 2 to 5 are diagrams sequentially showing press forming using the upper die 1 and the lower die 2. FIG. The thermoplastic resin used as the press material is impregnated with long fiber glass in advance. Thermoplastic resins include polyethylene, polypropylene, polycarbonate, polystyrene, polyvinyl chloride, polyacetal, polyethylene terephthalate, polyamide, and the like. Further, the average length of the glass fibers is 5 to 100 mm, which is longer than normal glass fibers. Of the total weight of long fiber glass-impregnated thermoplastic resin, the weight proportion of glass fiber is 20~55%, and the weight proportion of thermoplastic resin is 80~
It is 45%.

As shown in Figure 2, long fiber glass impregnated thermoplastic resin 8
is supplied and set on the press-formed product 5A of the lower mold 2. Before this supply set, the long fiber glass-impregnated thermoplastic resin 8 has been heat-treated, and subsequent press molding is performed at this heating temperature. This heating temperature is 190 to 220°C when polypropylene is used as the thermoplastic resin. In addition, during press molding, the upper mold 1 and lower mold 2 are kept at a temperature of 40 to 60°C, and at this temperature the long fiber glass-impregnated thermoplastic resin 8
Press mold.

In the example shown in FIG. 2, the long fiber glass-impregnated thermoplastic resin 8 is made into two layers of press molding material, upper and lower, and is supplied and set on the press molding surface 5A of the lower mold 2.
The supply set to the press molding surface 5A of the lower die 2 is 2
Two long fiber glass-impregnated thermoplastic resins 8 are divided into left and right parts at the protruding portions 6. In other words,
Two long fiber glass-impregnated thermoplastic resins 8 are placed on the press molding surface 5 of the lower die 2 with a space between them at the protruding portion 6.
The supply is set to A. After that, as shown in FIG. 3, the upper mold 1 connected to a lifting means such as a ram is lowered, the convex part 5 of the lower mold 2 is fitted into the recess 3 of the upper mold 1, and the molds are matched. The long fiber glass-impregnated thermoplastic resin 8 is pressed between the press-molded products 3A and 5A of the mold 1 and the lower mold 2. At this time, the press molding pressure due to the clamping force of upper mold 1 and lower mold 2 is 90~
It is 200Kg/ ^m2 .

As the compression between the upper mold 1 and the lower mold 2 progresses, it becomes clear that the long fiber glass-impregnated thermoplastic resin 8 has been previously heat-treated, the upper mold 1 and the lower mold 2 have also been heated, and the long fiber glass is heated. Since the press pressure is applied to the impregnated thermoplastic resin 8, the long fiber glass impregnated thermoplastic resin 8 is softened and becomes fluid. For this reason, as shown in FIG. 4, the press molding materials of the upper and lower two layers are mixed and integrated, and the interval between the two long fiber glass-impregnated thermoplastic resins 8, which have been separately supplied and set at the protruding portion 6, is reduced. As it narrows, a part of the long fiber glass-impregnated thermoplastic resin 8 that begins to flow passes through the gap 9 between the tip of the protrusion 6 and the press molding surface 3A of the upper die 1, and as a result, the protrusion 6 The two long fiber glass-impregnated thermoplastic resins 8, which were separated into left and right parts, are connected and integrated at the upper part of the protrusion 6. Upper mold 1, which was gradually lowering during this time
When reaches the lowering limit as shown in FIG.
The long fiber glass-impregnated thermoplastic resin 8 is filled in between, and press molding is performed by clamping the upper mold 1 and the lower mold 2.

In the above, the gap 9 is narrowly formed by the protrusion 6, and the size thereof is 0.15 to 0.15, as described above.
It is 0.5mm. Therefore, among the components of the long fiber glass-impregnated thermoplastic resin 8, glass fibers are difficult to flow into the gap 9, and the thermoplastic resin mainly flows. Therefore, 2
The connected and integrated portions of the two long fiber glass-impregnated thermoplastic resins 8 are connected by the thermoplastic resin. Note that if the gap 9 is set to 0.15 mm or less, the strength of the hinge portion will decrease, making it impossible to obtain the required strength. In addition, the hinge part is thicker than 0.5mm,
Desired hinge characteristics cannot be obtained.

When the upper mold 1 is lifted up and separated from the lower mold 2 and the molded long fiber glass-impregnated thermoplastic resin is taken out, a molded product 10 shown in FIG. 6 is obtained. This molded product 1
0, a groove 10A is formed by the protruding portion 6, and a thinned hinge portion 11 is provided by this groove 10A. The hinge portion 11 formed at a location corresponding to the protruding portion 6 is a connection portion between the two long fiber glass-impregnated thermoplastic resins 8, and is made of thermoplastic resin as described above. The hinge portion 11 has flexibility inherent to thermoplastic resin.

As a result of the above, the press forming surface 3 of the upper die 1 and lower die 2
A hinge portion 11 is formed on the molded product 10 at the same time that a press molding surface 10 having a predetermined shape imitating the shapes A and 5A is formed.

FIG. 7 shows another embodiment of the protrusion. A vertical groove 12B is formed in the lower mold 12 and extends from the press molding surface 15A, which is the upper surface of the convex portion 15, to the lower mold 12A of the lower mold 12, and the plate-like member 17 is inserted into the vertical groove 12B so as to be freely raised and lowered. By making the head 17A of the plate member 17 protrude from the press forming surface 15A, the protrusion 16 is provided at the head 17A. The plate member 17 includes a hydraulic cylinder, a cam mechanism (not shown),
It is raised and lowered by a lifting means such as a link mechanism. According to this, the size of the narrow gap formed by the protrusion 16 can be adjusted to an optimum value, and even if the thickness of the molding material supplied and set on the press molding surface 15A is changed, this can be adjusted. Be able to deal with.

In the above, the shape of the protrusion is arbitrarily set to a semicircular cross section, a rectangular cross section, a triangular cross section, etc. depending on the shape of the hinge part of the molded product. Further, the number of protrusions is not limited to one, and if a plurality of hinge parts are required for the molded product, the number of protrusions is plural. Further, in this embodiment, the lower mold is provided with a protruding portion, but the upper mold may be provided with a protruding portion, and the same effect as described above can also be obtained by this. Furthermore, in the case where there is a plurality of protrusions as described above, the protrusions may be provided on both the upper mold and the lower mold, and the two protrusions provided on the two molds may be made to face each other. A narrow gap may be provided between these protruding parts, and if necessary, at least one of the pair of molds may be provided with a protruding part that protrudes in the direction of the other mold. Bye.

[Effects of the Invention] According to the present invention, when obtaining a molded product by press-molding a long-fiber glass-impregnated thermoplastic resin, it is possible to simultaneously form a hinge portion on the molded product. In addition, even if the long fiber glass-impregnated thermoplastic resin is used as a press molding material, there is no need to limit the molded product to those that are not in the hinge part, and the degree of freedom in designing the molded product can be expanded.

[Brief explanation of drawings]

Fig. 1 is an overall perspective view of a pair of dies, an upper die and a lower die; Figs. 2, 3, 4, and 5 are sectional views showing press forming in order; Fig. 6 is a forming FIG. 7 is a cross-sectional perspective view showing another embodiment. 1, 2, 11, 12...A pair of molds, an upper mold and a lower mold, 6, 16...Protruding portion, 8...Long fiber glass impregnated thermoplastic resin, 9...Gap, 10... Molded product , 11... Hinge part.

Claims (1)

[Claims] 1 A press molding method in which a thermoplastic resin impregnated with long fiber glass is pressed between a pair of molds to form a molded product having a hinge part, the press molding method comprising: pressing a long fiber glass-impregnated thermoplastic resin between a pair of molds to form a molded product having a hinge part; A protrusion projecting in the direction is provided, and the long fiber glass-impregnated thermoplastic resin is divided at the part of the protrusion and supplied between the pair of molds, and the long fiber glass-impregnated thermoplastic resin is divided by the pair of molds. While compressing the resin, the long fiber glass-impregnated thermoplastic resin supplied separately is connected and integrated by flowing through the narrow gap formed by the protrusion, and the portion corresponding to the protrusion forms a hinge part. Press molding method for molded products.