JPH062361B2 - Method for manufacturing long synthetic resin molded products - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for manufacturing a long synthetic resin molded product such as a molding for a vehicle and a building material, and more particularly to a manufacturing method by extrusion molding.

[Conventional technology]

FIG. 8 is a perspective view showing a conventional manufacturing method disclosed in, for example, JP-A-57-207041. In the figure, reference numeral 1 denotes a molded product such as a molding, which is composed of a resin portion 2 and a core material 3, and a flat portion 4 is formed on a part of the outer surface 1a. The conventional method for producing a molded article 1 is to supply a molten resin and a core material 3 to an extrusion mold to extrude a molded article 1 having a resin part 2 and a core material 3 and to form a flat part near the exit of the extrusion mold. A tape 5 having rigidity is applied so as to cover 4 and then the tape 5 is peeled off to finish the flat portion 4 smoothly.

[Problems to be solved by the invention]

However, in such a conventional manufacturing method,
Since only a part of the outer surface side of the flat part 4 of the molded product 1 is covered with the tape 5 and the remaining part is directly extruded from the extrusion mold, there is no problem in the case of an opaque synthetic resin molded product, but a synthetic part having a transparent part. In the case of a resin molded product, there is a problem in that even if the outer surface of the transparent portion becomes smooth, uniform and clear transparency cannot be obtained.

The present invention is intended to solve the above problems, and an object of the present invention is to provide a method for producing a long synthetic resin molded product having a transparent portion with uniform and clear transparency.

[Means for solving problems]

The present invention is a method for extrusion-molding a long synthetic resin molded article having a transparent portion by supplying a light-transmitting molten resin to an extrusion molding die, wherein the outer surface side of the transparent portion of the molded article in the extrusion molding die and On the inner surface side, a tape that is incompatible with the synthetic resin and has a smooth and heat-resistant molded product side, and the widthwise both ends of the tape on the outer surface side are located inside the both axial ends of the tape on the inner surface side. Thus, the method for producing a long synthetic resin molded article is characterized in that the tape on both sides is peeled off after being adhered and extruded as described above.

As a result of examining the transparency of the transparent portion of the synthetic resin molded product, it was found that the smoothness on the inner surface side is an important factor together with the smoothness on the outer surface side of the transparent portion. That is, the transparency is visually recognized in a state where the transmission and reflection of light on the outer surface side and the transmission and reflection of light on the inner surface side are correlated, and clear transparency is obtained due to the high smoothness of both surfaces.

[Action]

In the manufacturing method of the present invention, since the tape is adhered to the outer surface side and the inner surface side of the transparent portion of the molded product and extrusion molding is performed, a smooth surface can be obtained in the portion covered with the tape. For this reason, the molded product is smooth on both sides, and a flat and glass-like uniform and clear transparency is obtained. The inner tape is wider than the outer tape, and the widthwise ends of the outer tape are located inside the widthwise ends of the inner tape, so the inner smooth surface is wider. Therefore, even when viewed obliquely from the outer surface side, the boundary line on the inner surface side is not visually recognized, and a clear parting line is formed on the outer surface side, which provides an excellent appearance.

〔Example〕

Hereinafter, the present invention will be described with reference to the embodiments of the drawings. First
FIG. 1 is a system diagram showing an embodiment of the present invention, FIGS. 2 to 5 show manufacturing steps thereof, FIGS. 2 and 3 are sectional views, FIGS. 4 and 5 are perspective views, and FIG. 6 and 7 are perspective views of another manufactured molded product, and the same reference numerals as in FIG. 8 indicate the same or corresponding parts.

In the figure, 11 is an extruder, 12 is an adapter, 13 is an extrusion mold, 14 is a take-up machine, and 15 is a cutting machine. As shown in FIGS. 6 and 7, the molded article 1 to be produced is formed into a long length by a resin portion 2 made of a light-transmissive synthetic resin such as methyl methacrylic resin, and has a strip-shaped transparent portion in the center portion. Two
The colored portion 2b is formed on a and both sides thereof.

In the manufacturing method of the molded product 1, the light-transmissive molten resin 16 is supplied from the tip of the extruder 11 to the extrusion mold 13 via the cylindrical adapter 12 and extrusion-molded into a predetermined cross-sectional shape. The extrusion mold 13 has a tapered tapered hole 13a through which the molten resin 16 passes and insertion holes 13b, 13 formed on both sides thereof.
c merges slightly inside the extrusion port 13d, and the molten resin 1 such as polyester resin is passed through the insertion holes 13b and 13c.
Tapes 5a and 5b made of a synthetic resin, which is incompatible with 6, and has heat resistance and rigidity, are supplied at the same speed as the extrusion speed, and are adhered to the outer surface 1a and the inner surface 1b of the molded product 1 in a sandwich form.

The tapes 5a and 5b have a thickness of about 30 to 50 μm, and at least the surface on the molded article 1 side has a smooth surface.
a has the same width as the transparent portion 2a and is attached to the outer surface 1a thereof,
The tape 5b is wider than the transparent portion 2a and has an inner surface 1b,
The tape 5a is attached so that both ends in the width direction of the tape 5a are located inside the both ends of the tape 5b in the width direction. The molten resin 16 in the extrusion mold 13 flows under a high pressure in the tapered tapered hole 13a, and the tapes 5a and 5b are pressed from both sides in a softened state by heating.
Is extruded in a state where the tapes 5a and 5b are in close contact with each other, and the outer surface 1a and the inner surface 1b of the molded product 1 to which the tapes 5a and 5b are adhered are smooth surfaces.

The molded product 1 exiting the extrusion mold 13 is taken by the take-up machine 14 and cut by the cutting machine 15 to obtain the molded product 1 of FIG. Next, when the molded product 1 is subjected to a coloring treatment such as coating with the coating gun 17 while the tapes 5a and 5b are adhered as shown in FIG. 3, a colored layer is formed on the entire outer surface 1a as shown in FIG. It Therefore, if necessary, a baking process is performed and the tapes 5a and 5b are peeled off as shown in FIG.
The adhered portion is exposed to form the transparent portion 2a, and the tape 5
The part where a and 5b are not adhered remains as the colored part 2b, and the molded product 1 of FIG. 6 is manufactured.

The molded product 1 of FIG. 6 is used as a vehicle molding. The molded product 1 shown in FIG. 7 is used as a building material such as a shutter material for a show window, and is manufactured in the same manner as described above.

The long molded product 1 manufactured in this manner is composed of the tapes 5a, 5a.
Since the smooth surface of the tapes 5a and 5b is transferred to the adhered surface of b, it becomes flat and glass-like and has a clear transparency. Since the tape 5b adhered surface on the inner surface 1b side is wider than the outer surface 1a side, both ends in the width direction of the tape 5a are located inside the both ends in the width direction of the tape 5b. Even when viewed obliquely from the surface side, the boundary line on the inner surface side is not visually recognized, and a clear linear parting line is formed on the outer surface side, which gives an excellent appearance.

If a normal temperature curable coating material is used for the coloring treatment, the baking step is unnecessary, but since the tapes 5a and 5b are heat resistant, the baking step does not adversely affect the molded article 1. As the light-transmissive synthetic resin, other resin such as polycarbonate resin can be used in addition to methyl methacrylic resin. The tapes 5a and 5b may be metal foil tape or the like in addition to synthetic resin, and the molded article 1 includes molded articles for vehicles, building materials and the like.

〔The invention's effect〕

According to the present invention, the tape is attached to the outer surface side and the inner surface side of the molded product such that both widthwise end portions of the outer surface side tape are located inside the widthwise both end portions of the inner surface side tape. After extruding, the tape was peeled off.
It is possible to form a wider smooth surface on the inner surface side than the outer surface side.Therefore, the parting line is not visible even when viewed in an oblique direction. A long synthetic resin molded product having the same can be obtained.

[Brief description of drawings]

FIG. 1 is a system diagram showing an embodiment of the present invention, FIGS. 2 to 5 show the manufacturing process thereof, FIGS. 2 and 3 are sectional views, and FIGS. 4 and 5 are perspective views. , FIG. 6 and FIG. 7 are perspective views of another manufactured molded product, and FIG. 8 is a perspective view showing a conventional manufacturing method. In the drawings, the same reference numerals denote the same or corresponding parts, 1 is a molded product, 2 is a resin part, 2a is a transparent part, 2b is a colored part,
5, 5a and 5b are tapes, 13 is an extrusion mold, 14 is a take-up machine, 15 is a cutting machine, and 16 is a molten resin.

Claims (2)

[Claims] 1. A method of extrusion-molding a long synthetic resin molded article having a transparent portion by supplying a light-transmitting molten resin to an extrusion molding die, wherein an outer surface side of the transparent portion of the molded article in the extrusion molding die. And a tape that is incompatible with the synthetic resin and that has a smooth and heat-resistant molded product side on the inner surface side, and the widthwise both ends of the tape on the outer surface side are located inside the both widthwise end portions of the tape on the inner surface side. The method for producing a long synthetic resin molded article, comprising the steps of depositing and extruding as described above, and then peeling the tapes on both sides. 2. The manufacturing method according to claim 1, wherein the outer surface of the molded product is colored before the tape is peeled off.