JP2604321B2 - Blowing agent composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a blowing agent composition.

[0002]

2. Description of the Related Art Organic foaming agents are now widely used as foaming agents for thermoplastic resins such as polyethylene, polypropylene, EVA and polyvinyl chloride, and rubbers, utilizing their excellent foaming properties.

[0003] However, since the organic foaming agent is usually a compound in the form of fine powder, it suffers from environmental pollution due to scattering of fine powder and safety and hygiene due to suction of fine powder, similarly to general powder. I have. Therefore, development of an organic foaming agent having no scattering property is strongly desired.

Heretofore, as a method for preventing the organic foaming agent from scattering, a method of wetting with a liquid plasticizer, a stabilizer, a crosslinking agent and the like, a method of granulating fine powder, and the like have been proposed.

[0005] However, the method of wetting with a liquid plasticizer, a stabilizer, a crosslinking aid or the like has a problem that the foaming performance is greatly changed by the influence of additives. In addition, this method has a problem that it solidifies over time and dispersibility in a resin decreases, and is not yet a satisfactory method.

[0006] The method of suppressing the scattering of fine powder by granulation is an extremely excellent method for preventing scattering, but has the disadvantage that dispersibility in resin is inferior to that of non-granulated powder. Have.

[0007]

SUMMARY OF THE INVENTION In view of the above-mentioned problems of the prior art, the present inventors have found that a composition which not only has an effect of preventing scattering but also does not adversely affect the foaming performance and has improved solidification with time. As a result of intensive studies in search of a product, surprising finding that all the above problems can be solved by adding a tetrafluoroethylene resin to an organic foaming agent has been obtained, and the present invention has been completed.

[0008]

That is, the present invention relates to a blowing agent composition comprising a tetrafluoroethylene resin mixed with an organic blowing agent.

Specific examples of the organic blowing agent of the present invention include azodicarbonamide (hereinafter abbreviated as “ADCA”), p,
p'-oxybisbenzenesulfonyl hydrazide (hereinafter abbreviated as "OBSH"), dinitrosopentamethylenetetramine (hereinafter abbreviated as "DPT"), p-toluenesulfonyl hydrazide (hereinafter abbreviated as "TSH") and the like. be able to. These organic foaming agents to be blended in the foaming agent composition of the present invention may be used alone or as a mixture of two or more.

[0010] The tetrafluoroethylene resin used in the present invention is not particularly limited, and the powder of the tetrafluoroethylene resin widely used for ordinary molding, additives, physical property modifiers and the like is widely used. Any conventionally known ones can be used as long as they are fibrous. Among these, powder or fibrous tetrafluoroethylene resin of 500 μ or less is preferable, and powdery tetrafluoroethylene resin is particularly preferable. The tetrafluoroethylene resin may be a copolymer of tetrafluoromethylene and another comonomer copolymerizable therewith.

In the present invention, the amount of the tetrafluoroethylene resin is not particularly limited, but is usually 0.01 to 10 parts by weight, preferably 0.1 to 10 parts by weight, per 100 parts by weight of the organic blowing agent. It is preferable to use about 2 parts by weight.
If the blending amount of the tetrafluoroethylene resin is too small, the effect of the present invention is not sufficiently exhibited, so that it is not preferable. Even if the blending amount exceeds 10 parts by weight, the effect is the same, which is economically disadvantageous.

The mixing of the tetrafluoroethylene resin with the organic blowing agent is not particularly limited, and a usual mixing method can be applied. However, when mixing, it is preferable to use a mixer that requires a torque as much as possible. For example, a mixer such as a Henschel mixer or a super mixer is preferably used. Further, by heating during mixing, the effect of the present invention can be further enhanced. Heating can be appropriately performed within a temperature range that does not cause decomposition or deterioration of the organic foaming agent, but is usually preferably performed at a temperature equal to or higher than normal temperature and equal to or lower than the decomposition temperature.

The blowing agent composition of the present invention contains Zn, P for the purpose of lowering the decomposition temperature or increasing the reaction rate.
Compounds such as b, Cd, and Cr, or urea or a urea-based compound may be blended. The foaming agent composition of the present invention may contain maleic acid, itaconic acid, trimellitic acid, fumaric acid and the like for the purpose of suppressing decomposition and the like.
Furthermore, the foaming agent composition of the present invention includes various resin stabilizers,
Pigments such as carbon black, titanium oxide, fibrous alkali metal titanate, chromium yellow, fillers such as calcium carbonate, antioxidants and the like may be added as necessary.

[0014]

The present invention will be further clarified with reference to the following examples. In this example, the scattering degree and the solidification test value were measured by the following methods.

Spattering degree: A watch glass having a diameter of 10 cm is placed on a horizontal surface, and 10.0 g of each foaming agent composition (sample) is dropped from a position 65 cm vertically above the center. The weight of the sample scattered from the watch glass was calculated from the value of the amount of the sample dropped on the watch glass, and the ratio of the scattered sample was defined as the degree of scatter.

Deposit solidification test value: 400 g of each foaming agent composition (sample) was filled in a 23 cm × 13 cm plastic bag, and after sufficiently degassed, heat-sealed openings were stacked, and 0.07 kg / A load of cm ² was applied. 2
After a week, the sample was taken out, sieved with a 14-mesh sieve, the weight of the non-permeate was measured, and the weight percentage was used as a test value for solidification.

Example 1 100 parts by weight of azodicarbonamide (Otsuka Chemical Co., Ltd.)
Manufactured) and powdered tetrafluoroethylene resin (hereinafter, referred to as
Using a super mixer (manufactured by Kawada Seisakusho), 0.2 part by weight of Asahi-ICI Fluoropolymers Co., Ltd. L150J (abbreviated as “PTFE”) was mixed at 40 ° C. and 600 rpm for 5 minutes to obtain a rice cake-like shape. A blowing agent composition was obtained.

Comparative Example 1 Untreated azodicarbonamide was used as Comparative Example 1.

Example 2 p, p'-Oxybisbenzenesulfonylhydrazide 1
00 parts by weight and 0.5 parts by weight of PTFE (K-10J, manufactured by DuPont-Mitsui Fluorochemicals Co., Ltd.) using a super mixer (manufactured by Kawada Seisakusho) at 50 ° C., 600 rpm
For 5 minutes to obtain a foaming agent composition.

Comparative Example 2 Untreated p, p'-oxybisbenzenesulfonylhydrazide was used as Comparative Example 2.

Reference Example 1 For the blowing agent compositions obtained in the above Examples 1 and 2, and the blowing agents of Comparative Examples 1 and 2, the above-mentioned scattering degree and deposition solidification test value were measured. It is shown in Table 1.

[0022]

[Table 1]

Reference Example 2 The foaming performance of the blowing agent composition obtained in Example 1 and the blowing agent of Comparative Example 1 were compared as follows. That is,
To each of the blowing agent composition obtained in Example 1 and 15 parts by weight of the blowing agent of Comparative Example 1, low-density polyethylene (MI 2.
0) A composition containing 100 parts by weight and 0.8 part by weight of dicumyl peroxide was kneaded while being heated at a roll temperature of 110 to 115 ° C., taken out into a sheet having a thickness of 5 mm, and then taken out at 125 ° C. for 5 minutes. A press sheet was formed by applying a pressure of 120 kg / cm ² and heating. The sheet thus obtained was foamed in a hot-air oven set at 220 ° C. In the obtained foam, the cells were uniform and fine for both the foaming agent composition of Example 1 and the foaming agent of Comparative Example 1.
It was a good foam having no difference in surface smoothness and decomposition rate.

[0024]

As can be seen from the examples and comparative examples in Table 1,
When a powdery or fibrous tetrafluoroethylene resin is added to the organic foaming agent, the soft tetrafluoroethylene resin expands in a mesh-like manner and wraps the organic foaming agent particles. Demonstrate
Further, since the networked tetrafluoroethylene resin plays a role of a cushion, an effect of preventing solidification of the organic foaming agent is exhibited. Further, as is apparent from Reference Example 2, a foaming agent composition having good foaming performance (decomposition rate, cell, surface properties, etc.) as well as an organic foaming agent without addition of a tetrafluoroethylene resin is obtained. I was able to. From such an effect, those skilled in the art can use the tetrafluoroethylene resin used in the present invention not only for a homopolymer of tetrafluoroethylene, but also for a copolymer having any copolymer component within a range that does not impair its flexibility. It is clear that this may be the case.

According to the present invention, it has become possible to solve environmental pollution due to scattering of the fine powder when handling the fine powder organic foaming agent, and also to the problem of safety and health due to suction of the fine powder. Furthermore, the solidification over time has been significantly improved,
It is possible to provide an organic foaming agent in which a decrease in dispersibility in a resin is suppressed even after storage or transportation for a long time.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor ▲ Tate ▼ Yoshifumi 649-2, Satoura, Satoura-cho, Naruto-shi, Tokushima Pref.

Claims (3)

(57) [Claims] 1. A blowing agent composition comprising an organic blowing agent and a tetrafluoroethylene resin. 2. The organic blowing agent is azodicarbonamide,
p, p'-oxybisbenzenesulfonyl hydrazide,
The blowing agent composition according to claim 1, which is at least one member selected from the group consisting of dinitrosopentamethylenetetramine and p-toluenesulfonylhydrazide. 3. The blowing agent composition according to claim 1, wherein the tetrafluoroethylene resin is a fibrous or powdery tetrafluoroethylene resin.