JPH07108548B2 - Plastic processing method for plastic materials - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a plastic working method for a plastic material containing a synthetic resin film or sheet.

(B) Problems to be Solved by Conventional Techniques and Inventions Conventionally, when a plastic material such as a metal foil or a metal plate is subjected to a plastic working such as drawing or book-working, it is applied only by pressure without heating. Is going. This is a processing method utilizing the malleability of a plastic material.

On the other hand, a synthetic resin film or sheet is also a plastic material, but since it melts or softens at a relatively low temperature,
It is processed into a predetermined shape using heat.

By the way, when it is desired to impart a predetermined shape to a composite material in which a metal foil or the like and a synthetic resin film or the like are adhered, it is conceivable to adopt the above-mentioned plastic working method or heat processing method. In the processing method using heat, the metal foil, etc. does not soften at the temperature at which the synthetic resin film softens. Therefore, plastic processing must be applied to the metal foil, etc. When doing, the adhesive used to attach the metal foil etc. to the synthetic resin film etc. may melt out, and if too much heat is applied the synthetic resin film etc. will melt and the composite material will be damaged. There are drawbacks such as storage. Therefore, in order to give a predetermined shape to a composite material of a metal foil or the like and a synthetic resin film or the like, since the synthetic resin film or the like is also plastic, it is not used in the conventional processing of the metal foil or the like. It is a good idea to adopt a method that involves plastic working that only pressurizes under heating.

However, synthetic resin films are composed of polymer chains at the molecular level, and when pressurized without heating, the polymer chains are oriented and crystallization occurs or is promoted, and that part turns white. There was that. For example, when a composite material is subjected to drawing or staking processing, the synthetic resin film or the like is whitened at the corners between the side wall of the central recess and the flange or between the side walls of the central recess and the bottom of the central recess. was there. This is because a particularly large stress is applied to the corner portion to promote the orientation of polymer chains. When such whitening occurs, it causes a drawback that the commercial value of the processed product is reduced.

Therefore, the present invention is intended to provide a plastic working method in which the above-mentioned whitening is prevented by using a specific material such as a synthetic resin film.

(C) Means and Actions for Solving the Problems That is, the present invention provides a synthetic resin film or a plastic material containing at least a synthetic resin film or a sheet, which is plastic-processed by pressurizing it without heating. The present invention relates to a plastic working method for a plastic material, which comprises kneading a white pigment into a sheet.

The plastic material used in the present invention contains at least a synthetic resin film or sheet. Therefore, it may be a synthetic resin film or sheet alone, or may be a composite material having a two-layer structure in which a metal material such as a metal foil or a metal plate is attached to the synthetic resin film or sheet. Further, it may be a composite material having two or more layers in which several synthetic resin films or sheets and a metal material are attached.

The synthetic resin film or sheet is made of polypropylene, polyethylene, polyester, etc., and the metal material such as metal foil or metal plate is made of aluminum, tin, copper, iron, etc. To be done.

In the present invention, the synthetic resin film or sheet is kneaded with a white pigment. Therefore, the synthetic resin film or sheet is originally colored white, and the plastic resin film or sheet does not change its color even if it is subjected to plastic working, particularly tensile working, so that the polymer chains are oriented and whitened.

As the white pigment, titanium oxide, zinc white, lithopone, zinc sulfide, lead white, zircon oxide, tin oxide, calcium carbonate, barium hydroxide and the like are used. Further, the kneading amount of the white pigment is preferably about 0.5 to 2 parts by weight with respect to 100 parts by weight of the synthetic resin.

Then, the plastic material having the synthetic resin film or sheet in which the white pigment is kneaded is pressed without heating and subjected to plastic working such as bending, drawing, and overhanging.

(D) Example A surface layer made of a transparent unstretched polypropylene film, an intermediate layer made of a white unstretched polypropylene film uniformly kneaded with 1% by weight of titanium oxide, an adhesive layer made of modified polypropylene, and an aluminum foil. Using a plastic material having a four-layer structure consisting of layers, a cylindrical drawing process was performed at a normal temperature by applying a pressure of 1 ton / cm ² . The drawing depth is 5m
m, and the diameter of the cylindrical portion was 70 mm.

As a result, the transparent surface layer becomes white at the corners between the side wall and the flange of the cylinder and the corners between the side wall and the bottom of the cylinder, while remaining transparent at the other parts. However, there is a layer in which titanium oxide is kneaded as an intermediate layer,
This layer is white in the corners as well as other parts. Therefore, the appearance of this processed product is white in all parts and has a uniform color.

As a comparative example, a three-layer structure obtained by removing the intermediate layer from the four-layer structure plastic material was subjected to cylindrical drawing under the same conditions as described above. As a result, since the corners of the transparent surface layer are whitened, the appearance of the processed product is such that the corners are white and the other parts have the color of aluminum.

(E) Effect of the Invention As described above, in the present invention, a plastic material containing a synthetic resin film or sheet in which a white pigment is kneaded is used to perform plastic working by applying pressure without heating. Therefore,
Even if the polymer chains in the synthetic resin film or sheet are oriented and the film or sheet is whitened, the color of the synthetic resin film or sheet changes as a whole because it is originally colored white with a white pigment. I don't do that. That is, if a plastic material in which the color of a synthetic resin film or sheet in which a white pigment is kneaded appears as an appearance, the appearance color will change even if various plastic processing is performed and the corners etc. are whitened. There is no.

Therefore, if the method of the present invention is adopted, even if a plastic material containing a synthetic resin film or sheet is pressed under non-heating to perform plastic working to produce a processed product, a white color appears locally. This has the effect of not lowering the product value.

Continuation of front page (56) References JP 59-64319 (JP, A) JP 55-9845 (JP, A) JP 51-38335 (JP, A) Shunichi Furuzumi "Thermal Heat" Molding ”Showa 60-9-30, published by Plastics Age Co., Ltd., pages 87, 106, 179

Claims (1)

[Claims] 1. When a plastic material containing at least a synthetic resin film or sheet is plastically processed by pressing without heating, a white pigment is kneaded with the synthetic resin film or sheet. Plastic working method for plastic materials.