JPH0441211A - Manufacture of polymer sheet having sea-island pattern - Google Patents

Abstract

PURPOSE:To obtain a nice looking polymer sheet, on the whole surface of which a sea-island pattern having desired extent is distributed uniformly and which has excellent outward appearance, by superposing a plurality of unvulcanized polymer sheets having different colors, pelletizing them, charging a fixed quantity of pellets into a molding cavity and press-vulcanizing the pellets. CONSTITUTION:A plurality of unvulcanized polymer sheets having different colors are superposed, and pelletized, and a fixed quantity of pellets are charged into a molding cavity, and press-vulcanized, thus manufacturing a polymer sheet having a sea-island pattern. The ethylene-vinyl acetate copolymer of vinyl acetate of 15-20% content, a styrene-butadiene block copolymerized rubber, etc., are used normally as the blank of the polymer sheet. Since pellets employed when the polymer sheet is manufactured have fixed volume ratios corresponding to the ratios of the thickness of each sheet stacked, the unvulcanized polymers having mutually different colors are mixed at a constant ratio at all times as a whole regardless of agitation. Accordingly, the areas and distribution of separate sea and island are kept approximately constant in all cases in the sea-island patterns of the sheets acquired by press-vulcanizing the pellets in the molding cavity.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Field of Application> The present invention relates to a method for producing a polymer sheet that allows a desired sea-to-island area to be obtained.

<Conventional technology> Kitchen seat, bathroom seat, beach sandals.

In order to attract consumers to purchase midsoles, wedges, insoles, etc. of shoes, it is desired to give them an attractive appearance, for example, a sea-island pattern.

Conventionally, polymer sheets that grow sea-island patterns have been produced by preparing multiple unvulcanized polymer sheets of different colors, applying each of the polymer sheets separately to a pelletizer, turning them into pellets, and then adding a predetermined amount of each pellet with a stirrer. The mixture was mixed, a predetermined amount of the mixture was put into a mold cavity, and press vulcanization was performed.

<Problems to be Solved by the Invention> The polymer sheet obtained by the conventional method is such that when the unvulcanized pellets are stirred with a stirrer, the pellets of different colors are stirred so that the entire amount of the pellets is evenly mixed with each other. Therefore, when the mixed pellets are placed in a mold cavity and subjected to revlace vulcanization, the sea area is wide in the formed areas and narrow in the island area, and conversely, the sea area is narrow in other areas. , the island area became wider and only a polymer sheet with an unsightly appearance was obtained.

The present invention aims to solve the problems that the conventional methods had.

<Means for Solving the Problems> The present invention is characterized in that a plurality of unvulcanized polymer sheets of different colors are piled up, pelletized, the pellets are charged in a predetermined amount into a mold cavity, and press vulcanized. The sea-
The gist of this paper is a method for manufacturing polymer sheets that increases product volume.

The material of the polymer sheet usually has a vinyl acetate content of 15
~20% ethylene-vinyl acetate copolymer (rE
VAJ), styrene-butadiene block copolymer rubber (usually referred to as thermoplastic rubber), and the like are used.

However, the polymer is not limited to the above material, and after vulcanization or crosslinking, the polymer may be a solid body or a foam body, and the hardness may be changed as appropriate.

Effect> The pellet used when manufacturing the polymer sheet having a sea-island pattern of the present invention has a fixed volume ratio depending on the thickness ratio of each layered sheet. Regardless of the stirring method, unvulcanized polymers of different colors are always mixed at a constant ratio.

Therefore, the sea-island pattern of the sheet obtained by press vulcanization in the mold cavity is approximately constant in all cases where the size and distribution of the individual seas and islands are all the same.

<Example>EVA" Stearic acid white carbon 11x Diethylene glycol foaming agent 1 Crosslinking agent $4 Ultramarine titanium oxide Blend I Blend H 100 parts by weight 100 parts by weight 1 #1 〃 5 〃 5 〃 0.5 〃0 .5 〃 5 〃 5 〃 2.5- 2.5 〃 〃 2 〃 3 〃 -〃 *1: A 6:4 blend of Ultrasen 634 and Ultrasen 630 manufactured by Toso Corporation.

*”: Tokuyama Vtatsu Co., Ltd. * VN-3 *3: Hydration Kasei Co., Ltd. Vinyhole AK *4: Nippon Oil & Fats Co., Ltd. Percmill D-40 formulation I was kneaded, and then the mixture was kneaded to a thickness of about 2 cranes. Roll it into a paper tube and wind it up into a paper tube. Top the rolled dough with the mixed wire dough of Mixture 5 to a thickness of about 2 cranes. Use a pelletizer to make pellets about 4 square inches in size. (hs+, side 3001fi,
Place the bottle in a mold with a cavity 16cm deep,
- Secondary crosslinking was carried out at a gauge pressure of 5, 5 kg/cga for 14 minutes, and then secondary crosslinking was carried out in a heating device at 75°C for 4 hours to obtain a polymer sheet of the present invention (specific gravity 0.15).

On the other hand, Formulation I and Formulation (2) were kneaded separately, then rolled to a thickness of about 2 fl and wound up into a paper tube, and the rolled up rolled dough was each made into pellets of about 4 cranes square size using a pelletizer. Equivalent amounts of these two types of pellets were thoroughly stirred, and a control polymer sheet (specific gravity 0.15) was obtained in the same manner as described above.

In the former case, the blue and white sea-islands were the same size and distributed almost evenly over the entire surface, but in the latter case, the size of the sea-islands was random, and they were unevenly distributed over the entire surface. Ta.

<Effects of the Invention> To obtain an extremely attractive polymer sheet in which a sea-island pattern of a desired size is uniformly distributed over the entire surface, even though no pellet stirring is required during the manufacturing process. was completed.

Claims (1)

[Claims] A method for producing a polymer sheet having a sea-island pattern, which comprises stacking a plurality of unvulcanized polymer sheets of different colors, pelletizing them, filling a predetermined amount of the pellets into a mold cavity, and press-vulcanizing them.