JPH033574B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a bright (pearlescent) metallic color on a foam.

As is well known, metallic colors appear in imitation pearls, thermoplastic resin injection molded products, vinyl chloride leather cosmetics, interior decoration products, painted products, etc. Metallic colors do not appear in foam products. The causes of this, which had been abandoned as it was considered impossible to make it appear, were the destruction of bismuth, the loss of brightness due to agglomeration, and the roughness of the surface.
Because of these factors, it was considered impossible to expect metallic luster from the foam, and research and development was hindered.

The present invention solves these problems, protects bismuth, which is a synthetic pearl foil, from destruction and agglomeration, overcomes surface obstruction, and makes it possible to express bright metallic luster on the surface of a splendid foam. It is an invention.

In the following, the present invention uses a rubber material in addition to a thermoplastic resin as the base material of the foam, creates unfoamed materials that each contain a foaming agent, and then After forming into a sheet,
In the case of sheets of thermoplastic resin, 10 or more sheets are stacked and placed in a cavity mold with dimensions of 500 m/m x 700 m/m, and the mold is heated to a pressure of 150 kg/ ^cm2. The sheets were pressed together and heated at 170°C for 20 minutes, and at the same time the pressure was removed, crosslinking and foaming were performed to obtain a foam in which the sheets were fused together. (This is to make the conductivity effective.) The foam produced by implementing the present invention shines all over the entire surface as if it were coated with a special coating, and has a clear metallic luster (pearl luster). A beautiful and satisfying product was obtained.

Hereinafter, to further explain the present invention in detail, the resin in the above-mentioned case using the thermoplastic resin and rubber used in the examples of the present invention is just an example, and even if it is a vinyl chloride resin or an olefin resin. often,
Furthermore, it was confirmed that among the olefin resins, a copolymer of vinyl acetate and ethylene gave the best results. Next, whichever resin is used, a foaming agent is added to impart foamability to the resin.
The foaming agent is preferably one that splits at a temperature higher than the softening point of the resin and generates gas, and when an olefin resin is used as the material, a crosslinking agent is added in addition to the foaming agent. When a copolymer of vinyl acetate ethylene is used as the material, it is preferable to use a compound such as azodicarbonamide as the blowing agent, followed by dinitrosopentamethylenetetramine.

Further, a peroxide such as dicumyl peroxide is used as a crosslinking agent. Furthermore, pigments, dyes, and fillers are mixed into the resin, and then bismuth, lead carbonate, or lead arsenate is mixed therein, and the mixture is kneaded using heated rolls, taking care not to destroy the bismuth crystals. Then, the sheet of unfoamed composition is molded while maintaining a proper roll temperature (below 90°) to prevent agglomeration.

Next, the present invention will be explained in further detail with reference to Examples.

(The parts in the examples represent parts by weight.) Example 1 Resin: A vinyl acetate ethylene copolymer with a vinyl acetate copolymer content of 15% by weight (manufactured by Toyo Soda Kogyo Co., Ltd., trademark Ultracene #630) ) Foaming agent: (manufactured by Eiwa Kasei Co., Ltd., trademark Vinyhole AK-
2) Crosslinking agent: (manufactured by Kayaku Nouri Co., Ltd., trademark Kayakumil D) 100 parts of the above resin, 6 parts of blowing agent, 1.4 parts of crosslinking agent, 1 part of stearic acid, 3 parts of magnesium carbonate, synthetic rubber (manufactured by Japan Synthetic Rubber Co., Ltd., trademark) JSR1502) 20 parts, coloring pigment 1.6 parts (bismuth), lead carbonate 5.2 to 6.5 parts, these mixtures were kneaded for 25 minutes using a mixing roll heated to 90°C and formed into a sheet with a thickness of 0.4 m/m. In this case, the thickness of this sheet is not necessarily
Although not limited to 0.4m/m, the thickness is
It was confirmed that the range from 0.1 m/m to 3 m/m does not affect the finished state of the foam. This sheet was cut into pieces with a width of 500 m/m and a length of 700 m/m, and was placed in a cavity mold in a press that had been preheated to 170°C and pressed at a pressure of 150 kg/ ^cm2 .
After 20 minutes, the pressure was removed and at the same time crosslinking and foaming were performed to obtain a foamed sheet with integrally fused sheets. Example 1 of this
As a result of the proper orientation of (bismuth) lead carbonate, the foam obtained by this method regularly reflects the incident light and causes multiple reflections, resulting in a strong metallic color with no concerns of shine, peeling, or discoloration. A product with brightness (pearl luster) was obtained.

Example 2 When the foam is mainly made of a rubber material, the manufacturing method is slightly different from that of the resin described above, and the manufacturing method is as follows.

Rubber material (manufactured by Japan Synthetic Rubber Co., Ltd., trademark 1R2000) 20 parts (〃 trademark BR-01) 25 parts (manufactured by Asahi Kasei Co., Ltd. trademark Solprene 303) 40 parts (〃 trademark Tuffden 2000) 15 parts The above 100 parts are the main raw materials, and the foaming agent TSH (Paratoluene Sulfur Acetone Hydrazone) (manufactured by Sankyo Kasei Co., Ltd., trademark Cellmic-K) 6 parts Stearin 1 part Carbon (manufactured by Nippon Silica Co., Ltd., trademark VN-3 White Carbon) 5 parts Diethylene Glycol 0.5 parts Vulcanization speed Vulcanization accelerator (manufactured by Sanshin Chemical Co., Ltd., trademark D, M 1.2 parts (manufactured by Sanshin Chemical Co., Ltd., 〃 M 0.3 parts) Super vulcanization accelerator (manufactured by Sanshin Chemical Co., Ltd., 〃 T, S 0.2 parts Sulfur 1.7 parts Transparent zinc white 0.5 parts Coloring pigment 1.5 parts (bismuth) Lead carbonate 5.5 parts The above ingredients are mixed and kneaded, but the first step is to wrap the rubber part around a roll,
The rubber is thoroughly kneaded, leaving only the lead carbonate, and all other chemicals are wound around a roll and mixed into the already thoroughly kneaded rubber, and thoroughly kneaded again. In this case, the time is 25 minutes, during which time the temperature of the roll is kept below 75°C.

The thickness of the kneaded rubber fabric is 8m/m to 10m/m.
Cut into pieces and ripen for about 12 hours.

The purpose of aging in this case is to prevent scorch and uneven foaming and to obtain a stable product. Next, divide the matured dough into 1/2 equivalent parts, mix the lead carbonate that has not yet been mixed into one of the separated dough, and knead it again to avoid destroying the crystals and preventing them from agglomerating. A sheet of unfoamed composition was formed while maintaining an appropriate roll temperature (preferably below 75°C), and the thickness was set at 2 m/m. The other half of the dough was rolled in the same way. While maintaining the temperature appropriately (preferably below 75°C), knead it and form it into a sheet with a thickness of 8 m/m.
The fabric mixed with lead (bismuth) carbonate, which had been finished, was pasted onto the sheet, and its cross section was made up of three layers: a normal fabric was set in the center, and sheets containing lead (bismuth) carbonate were superimposed on both sides. Then, the three-layered fabric was cut into pieces with a width of 500 m/m and a length of 700 m/m, and placed in a mold cavity in a press preheated to 150°C under a pressure of 150 kg/ ^cm2. After 15 minutes of pressurization, the pressure was removed and at the same time vulcanization and foaming were performed to obtain a foam in which the overlapped fabrics were fused together. Both sides of the foam (as a result of the proper orientation of bismuth lead carbonate) receive incident light regularly and cause multiple reflections, giving it a bright, strong metallic color (pearl luster) with no concerns of peeling or discoloration. Therefore, by carrying out the present invention, a metallic color with good illuminance (pearl luster), which was previously considered impossible, can be achieved on the surface of a foam mainly made of synthetic resin or rubber.
This invention has the effect that it is possible to make it appear clearly, and there is no fear of peeling or discoloration, and that when the present invention is applied to footwear, etc., it is possible to obtain footwear, etc. that can maintain its splendid appearance for any length of time. be.

Claims (1)

[Claims] 1. A kneading roll for mixing an unfoamed synthetic resin or rubber material containing a foaming agent with bismuth, lead carbonate, or lead arsenate was heated to 75°C to 90°C, and the mixture was kneaded for about 25 minutes with the kneading roll. After that, the sheets are formed into sheets, and the sheets are overlapped and placed in the cavity of a press preheated to 150°C to 170°C and pressed at approximately 150 kg/cm ² to fuse each sheet and foam at the same time as the pressure is removed. , A method for making a metallic color appear in a foam with good brightness, characterized by causing the foam to show a good brightness in a metallic color.