JPS6274621A - Manufacture of long sized synthetic resin molded part - Google Patents

Abstract

PURPOSE:To obtain a uniform sheet-glass like molded part with clear transparency by a method wherein the molded part is made by extrusion under the state that tapes are coated onto both surfaces of the transparent portion of the molded part in order to give the smooth flat surface to the portions covered with the tapes. CONSTITUTION:Synthetic resin tapes 5a and 5b, which are incompatible with molten resin 16 such as polyester resin or the like and has heat resistance and rigidity, are fed from inserting holes 13b and 13c with the speed same as the extrusion speed of the molten resin 16 into the outer surface 1a and the inner surface 1b of the molded part 1 so as to sandwich the molten resin. Because the molten resin 16 in an extruder die 13 flows under high pressure through a convergent hole 13a and, in addition, the tapes 5a and 5b are pressed onto both sides of the molten resin under the state softened by heating, the molded part 1 is extruded under the state that the tapes 5a and 5b are in close contact with the molded part. As a result, the outer surface 1a and the inner surface 1b, onto which the tapes 5a and 5b are coated, of the molded part 1 turn into smooth flat surfaces.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for manufacturing elongated synthetic resin molded products such as vehicle moldings and building materials, and particularly to a method for manufacturing by extrusion molding.

[Conventional technology]

FIG. 8 is a perspective view showing a conventional manufacturing method disclosed in, for example, Japanese Unexamined Patent Publication No. 57-207041. In fig.

1 is a molded product such as a molding, which is composed of a resin part 2 and a core material 3, and has a flat part 4 formed on a part of the outer surface 1a. The conventional manufacturing method for the molded product 1 involves supplying molten resin and core material 3 to an extrusion mold to form resin part 2 and core material 3.
A molded product 1 having the following properties is extruded, a rigid tape 5 is applied near the exit of the extrusion mold so as to cover the flat part 4, and the tape 5 is later peeled off to finish the flat part 4 smoothly.

[Problem that the invention seeks to solve]

However, in such conventional manufacturing methods,
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 rest is directly extruded from the extrusion mold, so there is no problem with opaque synthetic resin molded products, but synthetic resin molded products with transparent parts In the case of resin molded products, there is a problem in that even if the outer surface of the transparent part is smooth, uniform and clear transparency cannot be obtained.

This invention is intended to solve the above-mentioned problems, and aims to provide a method for manufacturing a long synthetic resin molded article having a transparent portion with uniform and clear transparency.

[Means for solving problems]

This invention relates to a method for extrusion molding a long synthetic resin molded article having a transparent part by supplying a light-transmitting molten resin to an extrusion mold, and in which , a long synthetic resin in which a heat-resistant tape that is incompatible with the synthetic resin is applied, and a tape wider than the tape is applied on the inner surface of the transparent part, extrusion molded, and then the tape is peeled off. This is a method for manufacturing molded products.

[For production]

In the manufacturing method of the present invention, extrusion molding is performed with tape applied to both sides of the transparent portion of the molded article, so that the portion covered with tape has a smooth surface.

As a result, both sides of the molded product are smooth, resulting in a uniform, clear transparency similar to that of a plate glass. Since the tape on the inner surface is wider than the tape on the outer surface, the smooth surface on the inner surface is wider. Therefore, even when viewed diagonally from the outer surface, the border line on the inner surface is not visible, and the border line on the inner surface is not visible. A clear parting line is formed on the surface, giving it an excellent appearance.

〔Example〕

Hereinafter, the present invention will be described with reference to embodiments shown in the drawings. 1st
The figure is a system diagram showing one embodiment of the present invention, FIGS. 2 to 5 show the manufacturing process, FIGS. 2 and 3 are sectional views, FIGS. 4 and 5 are perspective views, and FIGS. 6 and 7 are perspective views of other manufactured molded products, and the same reference numerals as in FIG. 8 indicate the same or corresponding parts.

In the figure, 11 is an extruder, and 12 is an adapter.

13 is an extrusion mold, 14 is a take-off machine, and 15 is a cutting machine. As shown in FIGS. 6 and 7, the molded product 1 to be manufactured is formed into a long resin part 2 made of a light-transmissive synthetic resin such as methyl methacrylic resin, and has a band-shaped transparent part 2a and a central part. Colored portions 2b are formed on both sides thereof.

The method for manufacturing the molded product 1 is to supply a light-transmitting molten resin 16 from the tip of an extruder 11 to an extrusion mold 13 via a cylindrical adapter 12, and extrude it into a predetermined cross-sectional shape. The extrusion mold 13 has a tapered hole 13a through which the molten resin 16 passes, and insertion holes 13b, 13 formed on both sides of the hole 13a.
c merge slightly inside the extrusion port L3d, and the molten resin 1 such as polyester resin flows from the insertion holes 13b and 13c.
Tapes 5a and 5b made of synthetic resin, which are incompatible with 6 and have heat resistance and rigidity, are supplied at the same speed as the extrusion speed, and are applied to the outer surface 1a and inner surface 1b of the molded product 1 in a sandwich-like manner.

The tapes 5a and 5b' have a thickness of about 30 to 50 μm.

At least the surface on the molded product 1 side has a smooth surface,
The tape 5a is of the same width as the transparent part 2a and is applied to its outer surface 1a, and the tape 5b is wider than the transparent part 2a and applied to its inner surface 1b. The molten resin 16 in the extrusion mold 13 flows under high pressure inside the tapered hole 13a, and also flows through the tape 5a.

5b is pressed from both sides while being softened by heating, so the molded product 1 is extruded with the tapes 5a and 5b in close contact with each other, and the tape 5a of the molded product 1.

The outer surface 1a and inner surface 1b to which 5b is adhered become smooth surfaces.

The molded product 1 that has come out of the extrusion mold 13 is taken by a take-off machine 14 and cut by a cutter 15 to obtain the molded product 1 shown in FIG. Next, as shown in FIG. 3, when the molded product 1 is subjected to a coloring process such as painting with a paint gun 17 with the tapes 5a and 5b still attached, a colored layer is formed on the entire outer surface 1a as shown in FIG. Ru. 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 a transparent portion 2a, and the tape 5
The portions to which a and 5b are not applied remain as colored portions 2b, and the molded product 1 shown in FIG. 6 is manufactured.

The molded product 1 shown in FIG. 6 is used as a molding for a vehicle. 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 way has tapes 5a, 5
Since the smooth surfaces of the tapes 5a and 5b are transferred to the adhered surface of b, the surface is smooth, so that a uniform and sharp transparency similar to that of a plate glass can be obtained. Since the surface to which the tape 5b is adhered is wider on the inner surface 1b side than on the outer surface 1a side, the boundary line on the inner surface side is not visible even when viewed diagonally from the outer surface side, and there is a clear border line on the outer surface side. A straight parting line is formed, giving an excellent appearance.

Note that if a room temperature curing paint is used for the coloring treatment, the baking process is not necessary, but since the tapes 5a and 5b are heat resistant, the baking process will not have an adverse effect on the molded product 1. As the light-transmitting synthetic resin, other resins such as polycarbonate resin can be used in addition to methyl methacrylic resin. Also tape 5a.

In addition to synthetic resin, metal foil tape or the like may be used as the material 5b. Furthermore, the molded product 1 includes molded products for vehicles, building materials, and others.

〔Effect of the invention〕

According to this invention, since the tape is applied to both sides of the molded product and the tape on the inner side is made wider, a long synthetic resin molded product having a transparent part with uniform and clear transparency and a clear parting line can be obtained. It will be done.

[Brief explanation of drawings]

Fig. 1 is a system diagram showing one embodiment of the present invention, Figs. 2 to 5 show its manufacturing process, 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 molded product manufactured, and FIG. 8 is a perspective view showing a conventional manufacturing method. In each figure, the same reference numerals indicate 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, 5b is a tape, 13 is an extrusion mold, 1
4 is a pulling machine, 15 is a cutting machine, and 16 is a molten resin. Agent Patent Attorney Sei Yanagihara Figure 5 Figure 8

Claims (3)

[Claims] (1) In a method of extrusion molding a long synthetic resin molded product having a transparent part by supplying a light-transmitting molten resin to an extrusion mold, on the outer surface side of the transparent part of the molded product in the extrusion mold, Long synthetic resin molding in which a heat-resistant tape that is incompatible with the synthetic resin is applied, and a tape wider than the tape is applied to the inner surface of the transparent part, extrusion molded, and then the tape is peeled off. method of manufacturing the product. (2) The manufacturing method according to claim 1, wherein the tape has a smooth surface on the molded product side. (3) The manufacturing method according to claim 1 or 2, wherein the outer surface of the molded product is colored before peeling off the tape.