JP2003292661A - Polyolefin resin composition for foaming and foam composed of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyolefin resin composition for foaming capable of significantly improving problems associated with deterioration of working circumstances due to the ammonia malodor by reducing ammonia generated from foamed products in foaming, and a foam composed of the composition. <P>SOLUTION: The composition contains 1-40 parts by weight of a chemical foaming agent and 1-100 parts by weight of aluminum powder in 100 parts by weight of a polyolefin resin. The foam is composed of the composition. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a polyolefin resin composition for foam molding, and more specifically to a polyolefin resin composition for foam molding for supplying a foam having a reduced ammonia odor and a polyolefin resin composition for foam molding. The present invention relates to a foam.

[0002]

2. Description of the Related Art Conventionally, azodicarbonamide or a mixture of azodicarbonamide and p, p'-oxybisbenzenesulfonyl hydrazide (hereinafter referred to as OBSH) has self-extinguishing property and high safety. It is widely used as a chemical foaming agent in the production of thermoplastic resin foams because of the large amount of gas generated during decomposition.

Further, when a thermoplastic resin is foamed using these chemical foaming agents, the decomposition behavior of azodicarbonamide may differ depending on the foaming conditions such as the type of the thermoplastic resin to be foamed or the processing temperature. Urea, lead carbonate, ethanolamine, sodium bicarbonate, zinc oxide, etc. are added as chemical foaming aids to control the decomposition of azodicarbonamide because it is necessary to match the decomposition temperature of the chemical foaming agent to the proper melting temperature for resin foaming. Is known to do.

[0004]

However, when a foamable thermoplastic resin composition in which these chemical foaming agents or chemical foaming aids are used together is subjected to foam molding, ammonia odor is generated together with nitrogen gas due to thermal decomposition. There has been a problem that the odor of ammonia remains in the molded product for a long time and the odor of ammonia remains for a long time. Further, even if there is no ammonia odor at room temperature, ammonia odor may be generated again when thermoforming is performed again, which is a problem. further,
The polyolefin resin composition for foam molding has no ammonia odor or has a reduced ammonia odor because it gives an unpleasant feeling to a worker in terms of a work environment at the time of producing a foam, and also requires the cost of installing a removing device. Was strongly demanded.

Therefore, an object of the present invention is to provide a polyolefin resin composition for foam molding which has little or no ammonia odor when formed into a foam, and a foam comprising the same.

[0006]

Means for Solving the Problems As a result of extensive studies on the above problems, the present inventor
The inventors have found that by mixing a specific amount of a chemical foaming agent and a specific amount of aluminum powder, it is possible to reduce the odor of ammonia when subjected to foam molding, and have completed the present invention.

That is, the present invention relates to a polyolefin resin 1
The present invention relates to a polyolefin resin composition for foam molding, which comprises 1 to 40 parts by weight of a chemical foaming agent and 1 to 100 parts by weight of aluminum powder with respect to 00 parts by weight, and a foam comprising the same. .

The polyolefin resin used in the present invention is not particularly limited as long as it belongs to the category of polyolefin resins, for example ethylene, propylene,
A homopolymer of an α-olefin having about 2 to 8 carbon atoms such as butene-1, the α-olefin and ethylene, propylene,
Butene-1,3-methylbutene-1, pentene-1,4
-Methylpentene-1, hexene-1, octene-1,
Other α-olefins having about 2 to 20 carbon atoms such as decene-1 and copolymers with vinyl acetate, acrylic acid, methacrylic acid, acrylic acid ester, methacrylic acid ester and the like can be mentioned. Is a branched ethylene homopolymer such as low / medium / high density polyethylene or a linear ethylene homopolymer, an ethylene-propylene copolymer, an ethylene-butene-1 copolymer, an ethylene-4-methylpentene-1. Copolymer, ethylene-hexene-1 copolymer,
Ethylene-octene-1 copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate copolymer , Ethylene-propyl acrylate copolymer, ethylene-butyl acrylate copolymer, ethylene-hexyl acrylate copolymer, ethylene-octyl acrylate copolymer, ethylene-methyl methacrylate copolymer, ethylene-methacrylic acid Ethyl copolymer, ethylene-propyl methacrylate copolymer, ethylene-butyl methacrylate copolymer,
Ethylene-hexyl methacrylate copolymer, ethylene-
Ethylene resins such as octyl methacrylate copolymer; propylene homopolymer, propylene-ethylene copolymer,
Propylene-based resins such as propylene-ethylene-butene-1 copolymer; butene-1 based resins such as butene-1 homopolymer, butene-1-ethylene copolymer, butene-1-propylene copolymer and the like. To be

The chemical foaming agent used in the present invention includes:
There is no particular limitation as long as it is a chemical foaming agent used when producing a foam, and examples thereof include benzenesulfonyl hydrazide, benzene-1,3-sulfonyl hydrazide, diphenylsulfone-3,3′-disulphonyl hydrazide,
Sulfonyl hydrazide compounds such as diphenyl oxide-4,4'-disulfonyl hydrazide, OBSH, paratoluene sulfonyl hydrazide; for example, azodicarbonamide, 2,2'-azobisisobutyronitrile,
Examples thereof include azo compounds such as azohexahydrobenzonitrile and diazoaminobenzene. Among them, in the present invention, azodicarbonamide alone or a mixture of OBSH and azodicarbonamide is particularly preferable because it is a polyolefin resin composition for foam molding which is extremely excellent in foaming efficiency.

As the aluminum powder constituting the polyolefin resin composition for foam molding of the present invention, known aluminum powder can be used.
The aluminum powder can be obtained, for example, by a method of atomizing molten aluminum in a mist state to form fine particles (gas atomizing method).

The polyolefin resin composition for foam molding of the present invention is based on 100 parts by weight of the polyolefin resin.
1 to 40 parts by weight of chemical foaming agent and 1 aluminum powder
The amount of the chemical foaming agent is less than 1 part by weight, so that the foaming effect of the obtained polyolefin resin composition is reduced. On the other hand, when the amount of the chemical foaming agent exceeds 40 parts by weight, the moldability of the resulting polyolefin resin composition for foam molding when it is subjected to molding processing becomes poor. Further, when the amount of aluminum powder is less than 1 part by weight, there is no effect of reducing the ammonia odor when the obtained polyolefin resin composition for foam molding is subjected to foam molding. Aluminum powder is 10
If the amount exceeds 0 parts by weight, not only the foamability of the resulting polyolefin resin composition for foam molding that is subjected to foam molding will deteriorate, but also problems will occur in terms of cost.

The method for preparing the polyolefin resin composition for foam molding of the present invention is not particularly limited, and 100 parts by weight of the polyolefin resin is added to the chemical foaming agent 1 to 40.
Any method can be used as long as it is possible to mix 1 part by weight and 1 to 100 parts by weight of aluminum powder. For example, after mixing with a mixer such as Henschel mixer, V-blender, ribbon blender, tumbler blender, Examples thereof include a method of melt-kneading with a melt-kneader such as a single-screw extruder, a twin-screw extruder, a kneader or a Banbury mixer.

Further, the polyolefin resin composition for foam molding of the present invention may contain a foaming accelerator and / or a foaming aid for the purpose of lowering the decomposition temperature of the chemical foaming agent during heat foaming. You can also Examples of the foaming accelerator or foaming aid include inorganic salts such as zinc white, zinc nitrate, lead phthalate, lead carbonate, trichlorophosphate, and tribasic lead sulfate; zinc fatty acid soap, lead fatty acid soap Metallic soaps such as cadmium fatty acid soaps; acids such as boric acid, oxalic acid, succinic acid, adipic acid; urea, ethanolamine, glucose, glycerin and the like.

The polyolefin resin composition for foam molding according to the present invention can be used within a range not hindering the achievement of the object of the present invention.
In addition to the above additives, pigments, dispersants, resin stabilizers, crosslinking agents or other foaming aids may be added.

By subjecting the polyolefin resin composition for foam molding of the present invention to a foam molding method which is usually used, various foams with reduced ammonia odor can be obtained.

[0016]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the examples.

The method for measuring the amount of ammonia generated from the foams obtained in Examples and Comparative Examples is shown below.

2.0 g of the obtained foam is placed in a 200 ml cylindrical glass tube installed in a tubular electric furnace heated to 60 ° C., and heated while flowing an inert gas (argon). Then, put 50 ml of water in the gas trap device,
The generated gas was bubbled. After bubbling gas for 5 hours, ammonia ions in the obtained aqueous solution were subjected to ion chromatography (trade name: IC-20, manufactured by Tosoh Corp.).
The amount of ammonia generated was quantified in 01).

Example 1 Azodicarbonamide (manufactured by Eiwa Chemical Industry Co., Ltd., trade name VINYALL AC # 50) per 100 parts by weight of low-density polyethylene (trade name Petrosene 190, manufactured by Tosoh Corp.)
S) 15 parts by weight, 3 parts by weight of aluminum powder, 0.7 parts by weight of dicumyl peroxide, and 0.5 parts by weight of zinc stearate were kneaded with a mixing roll to prepare a polyolefin resin composition for foam molding.

The obtained polyolefin resin composition for foam molding was filled in a 20 mm × 60 mm × 60 mm pressure-sealed mold, heated at 165 ° C. for 30 minutes, and then depressurized to prepare a primary foam. Then, this foam was heated in a heating bath at 180 ° C. for 20 minutes to prepare a foam having uniform and fine cells.

The amount of ammonia generated from the obtained foam was 90 ppm, the working environment was not deteriorated, and the odor of the foam was at a level at which there was no problem.

Comparative Example 1 A polyolefin resin composition for foam molding and a foam were prepared in the same manner as in Example 1 except that aluminum powder was not added.

The amount of ammonia generated from the obtained foam was very large at 900 ppm, and there were problems of ammonia odor of the foam and deterioration of working environment.

[0024]

EFFECTS OF THE INVENTION The polyolefin resin composition for foam molding of the present invention not only greatly improves the problem of deterioration of working environment due to ammonia odor during foam molding, but also reduces the amount of ammonia remaining in the foam. It can be greatly reduced.

Claims (3)

[Claims] 1. A polyolefin resin composition for foam molding, which comprises 100 parts by weight of a polyolefin resin and 1 to 40 parts by weight of a chemical foaming agent and 1 to 100 parts by weight of aluminum powder. 2. The polyolefin resin for foam molding according to claim 1, wherein the chemical foaming agent is azodicarbonamide alone or a mixture of azodicarbonamide and p, p′-oxybisbenzenesulfonyl hydrazide. Composition. 3. A foam obtained by foaming the polyolefin resin composition for foam molding according to claim 1.