JPS605167B2 - Method for manufacturing foam with uneven pattern - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for producing a foam having an uneven pattern.

Conventional methods for producing foams with uneven patterns include flooring materials,
As can be seen in wall materials, synthetic leather, shoe soles, etc.; '1) Foamed materials and then embossed with a boss roll or press to give an uneven pattern; {2) Printed on the surface of the sheet. A foam manufacturing composition containing a strainer, a foaming agent, and/or an inhibitor is foamed to create an uneven pattern; Each type of material has its own characteristics.

However, these conventional methods each have the following major drawbacks. That is, in method 01, the number of man-hours increases due to the operation of adding an uneven pattern after forming the foam, {method 21 requires a printing process, and there is a certain limit to the depth of the uneven pattern; Furthermore, the method of [31] requires a step of imparting a pattern to the mold, has the disadvantage that the pattern is limited, and the cost of the mold is extremely large. The present inventor has completed the present invention as a result of continuing intensive research to develop a simple method that does not require extra steps in order to overcome the difficulties of these conventional methods. The present invention provides an uneven pattern, which is characterized in that when manufacturing a foam, the expansion ratios of the inside of the foam and the skin part are made different during molding, and cracks are created in the skin part based on the expansion ratio, thereby imparting an uneven pattern. This relates to a method of manufacturing a foam having the following properties.

The feature of the present invention is that by changing the expansion ratio between the inside of the foam and the skin part during foam molding, the difference in expansion ratio causes cracks in the skin part to give an uneven pattern.

For this reason, there is no need for any secondary processing after foaming, and there is no need to create a pattern on the mold, and the shallowness and depth of the uneven pattern can be adjusted quite freely by adjusting the difference in foaming ratio.・In the present invention, a typical example of a means for changing the foaming ratio between the inside of the foam and the outer skin is a means of changing the amount of foaming agent added to the inner fabric and the outer skin fabric. The amount of foaming agent in the skin is greater than that in the skin.

At this time, the amount of the foaming agent in the inner fabric is 1 to 20 parts by weight per 10 parts by weight of the resin, and the amount of the foaming agent in the outer skin ranges from 0 to 1 part by weight per 10 parts by weight of the resin. It may be selected appropriately so that the amount is always large. The difference in foaming ratio is usually 2 to 2 for the inside and 1 to 1M for the skin, and the foaming ratio for the former should be higher than the latter. It is preferable that it be twice or more. The resin used in the present invention is not particularly limited, but representative examples include polyethylene, polypropylene, polybutene, ethylene-propylene copolymer, ethylene-butene copolymer,
Examples include polyolefins such as chlorinated polyethylene, polybutadiene, polyisoprene, polyisobutene, various polyamides, polyvinyl chloride, polystyrene, and ethylene-vinyl acetate copolymers.

As the resin used for the skin part, it is preferable to select a resin that easily cracks during foaming. For example, when heated (100
~200 qo) and relatively weak in terms of strength, such as polybutadiene, polyisoprene, and styrene-butadiene copolymers. The same resin or different resins may be used for the outer skin and the inside, but if different resins are used, an appropriate adhesive phase should be provided between the two, or both. It is preferable to provide a mixed layer of the two resins, and more preferably a copolymer layer of monomers constituting both resins.

The blowing agent used in the present invention is not particularly limited, and a wide range of conventionally used blowing agents can be used.
For example, azodicarbonamide, dinitrobentamethylenetetramine, p-toluenesulfonylhydrazide, 4,4-oxybis(benzenesulfonylhydrazide), azoisobutyronitrile, barium azodicarboxylate, sodium carbonate, bicarbonate. ammonium,
Examples include sodium bicarbonate.

These blowing agents can be used together with auxiliary agents if necessary.
Various auxiliaries can be selected from a wide range as appropriate, and specific examples include urea or its derivatives, salicylic acid, stearic acid, phthalic acid,
Examples include metal soaps of metal oxides such as maleic acid and zinc, and fatty acid metal soaps such as zinc stearate. In addition, in the present invention, a crosslinked foam can be obtained by using a crosslinking agent in combination, and in this case, any of the crosslinking agents that have been used in the past can be effectively applied. Mil peroxide, t-butylcumyl/di-t-oxide, 2,5-dimethyl 2,5-di-t-butyl/g-oxide hexane, 2,5-dimethyl 2,5-di-t-
Butyl/guoxyhexane-3,Q,Q-bis(t-butylpadoxy)diiso-propylbenzene, 1
-1-bis(t-butylperoxy)3,3,5-trimethylcyclohexane, etc. can be exemplified.

In carrying out the present invention, a predetermined resin, a blowing agent, and if necessary a crosslinking agent, a blowing aid, and other additives are kneaded, followed by foaming and molding.

Foaming and molding at this time is carried out at normal pressure or pressurization, usually at normal pressure - 100k.
It is heated to about 80 to 210 g' to carry out foaming and molding at the same time. Examples of additives that may be used as necessary at this time include various pigments, fillers, auxiliary additives, etc. More specifically, examples include light calcium carbonate, clay, white carbon, talc, and various coloring pigments. will appear.
In the present invention, the size of the uneven pattern can be changed by changing the thickness of the skin part, and if the thickness is made thinner, the uneven pattern will increase per unit area, resulting in a 4-square uneven pattern, and vice versa. If the thickness is increased, the uneven pattern becomes smaller per unit area, resulting in a larger uneven pattern.

Furthermore, by increasing the difference in foaming ratio between the inside and the skin, the uneven pattern can be made smaller. The concavo-convex pattern formed by the method of the present invention has the following features: 1. The concave-convex pattern cuts in at right angles from the surface 2. The depth of the concavo-convex pattern can be made more than 5 feet 3. Only the outer skin can be made particularly hard 4. Abrasion resistant Improved properties 5. When used for brushing items, etc., it has features such as preventing slippage due to water wetting, etc.

Example 1 The inner fabric of the foam and the outer skin part were prepared using the following formulation.
A low was prepared.

RB-82o (Japan) ■Synthetic rubber■
(manufactured by) 100 parts by weight loo parts by weight DOP (manufactured by Mitsui Petrochemical Industries, Ltd.) 0.2 〃 0.2 〃Calcium carbonate 30'' Developing agent (DAM: 6.0
〃 1.0'' (manufactured by Sankyo Kasei)) Each of the above blends was thoroughly kneaded with a roll at 100 to 110 qo, and the blend was divided into sheets with a thickness of 2 to 3 willows. and {Low's formulation is divided into sheets with a thickness of 1 skin.

Then, stack 4 sheets obtained from the formulation of
On top of that, one sheet obtained from the mixture (o) was stacked and filled into a mold, sealed, and a pressure of 100 k9/base was applied to it at a temperature of 140 to 150 mm to 10 to 100 mm.Heat it. The pressure was then removed to obtain a foam having an uneven pattern on the surface.The cross section of the foam was as shown in Figure 1, and its physical properties were as follows: Skin hardness 60 (C type hardness tester) ) Internal 〃〃 45 ( 〃 )
Linear expansion coefficient: 1.7 times Specific gravity: 0.20 Expansion ratio 5 Example 2 Foam inner fabric 'A' and outer skin area fabric (B) were prepared using the following formulations.

Bamboo) 8VAU630 (manufactured by Toyo Soda ■) 100 parts by weight DO
P.I. 0″ Calcium carbonate 30 Foaming agent (same as Example 1) 6
0 〃 (mouth) Toughprene A (manufactured by Asahi Kasei ■) 80 parts by weight HVAU6
30 20DOP
O. 2'' Each of the above formulations and {o} were treated in the same manner as in Example 1 to obtain a foam having an uneven pattern.

The skin part was non-foamed, transparent, and highly hard. The cross section of the obtained foam is as shown in Figure 2.
Its physical properties were as follows. Skin hardness
65 (C type hardness tester) inside 4
5 (〃) Linear expansion coefficient
1.7 times specific gravity
0.20 foaming ratio
5 Example 3 In Example 2, all treatments were carried out in the same manner as in Example 2 except that the thickness of the sheet in the case of the skin part {o} was changed to 1.5 ribs.

The uneven pattern of the obtained foam was several times larger than that of Example 2, and its depth was on the 1.5 side. Its cross section was as shown in FIG. 3, and its physical properties were as follows. Hardness of the skin part: 65 (C type hardness tester)
Internal 〃 〃 45 ( 〃 ) linear expansion coefficient 1.7 times specific gravity
0.20 foaming ratio
5

[Brief explanation of drawings]

1 to 3 are drawings showing cross sections of the foams obtained in Examples 1 to 3 of the present invention, and in each figure, 1 indicates the skin portion and 2 indicates the inside. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. When manufacturing a foam, the foaming ratio is made different between the inside of the foam and the skin part during molding, and cracks are created in the skin part based on the foaming ratio to give an uneven pattern. Foam manufacturing method.