JPS6361169B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for performing painting simultaneously with injection molding.

Conventional methods for painting injection molded products include the insert method, in which a pre-printed sheet is placed in an injection mold and the molding is painted;
There are methods such as hot-stamping the molded product afterwards or vacuum laminating printed sheets.

Each of these methods has its own characteristics; in the insert method, the sheet must be preformed in advance using a mold, and the types of sheets are limited.
The hot stamping method has the disadvantage that it can only transfer onto smooth or gently curved surfaces.

Since the vacuum lamination method involves post-processing using a laminating machine, the process is complicated and leads to increased costs.

Therefore, a method of molding by attaching a hot stamp to an injection mold has been considered, but all conventional methods have poor production efficiency, and improvements in this respect are desired.

The present invention has been made in view of this problem, and is an improvement to the method of supplying film for hot stamping.

Embodiments of the present invention will be described below based on the drawings.

1 to 3 illustrate each step of the method of the invention.

In the figure, 10 is a pattern transfer film, 12
14 is a roll for winding up the film, and 14 is a roll for winding up the film unwound from the roll.

The film 10 has a base material made of nylon or the like having good elongation properties, and a pattern is printed on the base material. 16 is the ink. The rolls 12 and 14 are installed at a predetermined interval, of which the one on the winding side 14 is driven, and the one on the unwinding side 12 is an idle roller but is provided with a brake device.

Further, 18 is a male type having a runner 20, 22
is a bracket 2 that supports the rolls 12 and 14;
4 is a fixed female mold, and 26 is a hot air injection nozzle. Here, the male mold 18 is fixed, the female mold 18 is fixed, and the female mold 22 is movable (of course, the reverse is also possible), and the cavity 28 formed by the two is formed by the film between the rolls 12 and 14. It is set so that it is located away from the surface.

In order to carry out injection molding and painting using the above-mentioned apparatus, the film 10 is slightly pulled between the rolls 12 and 14 and stopped, as shown in FIG. is softened. Note that instead of the hot air heating method, heating may be performed using a heater.

Next, as shown in FIG. 2, the female mold 22 is moved toward the male mold by a hydraulic device (not shown), and the male mold 18
It is made to match the pattern. As a result, the film 10 between the rolls is placed in the cavity 28 while being stretched, and then the molten resin 30 is injected into the cavity. The injection resin 30 is, for example, ABS, PS,
PP, PE, urethane, acrylic, etc. These resins do not weld to the film 10. The film 10 is brought into close contact with the wall surface of the cavity 28 by the pressure of the injection resin, and the ink 16 on the film adheres to the injection resin surface.

After the injected resin 30 has cooled to some extent, the male and female molds 18 and 22 are separated as shown in FIG. Then, the roll 14 is driven and the other rolls 12 are braked. As a result, most of the recesses in the film formed during the forming process are eliminated by the tensile force, after which the brake of the roll 12 is released and the film is wound onto the roll 14. Hot air may be blown from the nozzle 26 during this tensioning.

Then, the state returns to the state shown in FIG. 1 and waits for the next molding.

As described above, in the injection molding simultaneous painting method according to the present invention, a transfer film is sandwiched between male and female molds that form a cavity at a position apart from the surface of the transfer film, and after injection molding, painting, and mold release, the film is Since the film is pulled in a stopped state, even if the molded product has a complex curved surface and a deep rise, the concave part of the film will be eliminated after molding, and the flat surface around it will be removed from the mold joint. Since it floats, it is possible to smoothly supply and discharge the film.

[Brief explanation of drawings]

The figures show schematic vertical cross-sectional views of a mold illustrating the method according to the present invention, in which FIG. 1 is an explanatory diagram of a molding preparation step, FIG. 2 is a molding and painting step, and FIG. 3 is an explanatory diagram of a molded product discharging step. 10... Transfer film, 12, 14... Roll, 16... Ink, 18... Male mold, 22... Female mold, 26... Nozzle, 28... Cavity, 30
...Injection resin.

Claims (1)

[Claims] 1. An injection molding simultaneous painting method comprising the following matters. (a) A pattern is printed in advance on a film with good elongation properties, and a roll for winding this film and a roll for winding the film unwound from the roll are installed at a predetermined interval, and these rolls are rotated intermittently. (b) blowing hot air onto the film stopped between the two rolls to soften the film; (c) separating the softened film from the film surface; (d) After separating the male and female molds, applying a tensile force to the film between the rollers, Separating the film from the mold cavity