JP2001151950A - Flame-retardant resin composition and molded article thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a novel resin composition which does not contain a halogen compound and has a high flame retardance. SOLUTION: The composition is obtained by compounding a polyolefin resin with (A) 10-60 wt.% hydrated metal oxide and (B) 1-36 wt.% melamine salt of at least one inorganic acid selected from among nitric, sulfuric, polyphosphoric, boric, phosphorous, and sulfurous acids in a ratio of B/(A+B) of 0.1-0.6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flame-retardant resin composition containing no halogen compound, and further to a molded article such as an electric wire, an automobile interior material, a building material film, an electric component, etc. using the same.

[0002]

2. Description of the Related Art Conventionally, thermoplastic resins have been used in a wide range of fields because of their excellent moldability, lightness, durability, and electrical insulation. However, since it is an organic material unlike an inorganic material represented by a metal, it has a drawback that it is inherently flammable. Since flame retardancy is indispensable from the viewpoint of fire prevention, a flame retardant resin composition in which various flame retardants are blended with a thermoplastic resin has been proposed and disclosed.

In order to impart flame retardancy to a thermoplastic resin,
It has been common practice to mix an organic halogen compound and antimony trioxide and utilize the chemical and physical synergistic effects of both. However, a resin composition containing an organic halogen-based compound is regarded as a problem due to hydrogen halide gas generated during combustion or molding processing or when a molded article is incinerated, or corrosiveness of an organic halogen-based compound. Was.

[0004] In order to eliminate such disadvantages, a method of adding a hydrated metal oxide has been used, but it has been necessary to add a large amount due to insufficient flame retardancy. For example, "Polymer Digest", Volume 51, 1 , pages 61, 199
9, red phosphorus, a metal compound, a nitrogen compound,
It was used in combination with various flame retardant aids such as silicone compounds.

[0005]

The use of a melamine salt as a flame retardant is described in Japanese Patent Publication No. 61-44095, and melamine phosphate is mentioned as an example of an organic phosphate. JP-A-7-330980 discloses a flame-retardant resin composition containing melamine, melamine cyanurate, a hydrated metal oxide and talc as essential flame retardants for nitrogen compounds. Melamine cyanurate is disclosed as a specific example. However, further improvement has been desired in order to demand higher flame retardancy.

[0006]

Means for Solving the Problems A first invention of the present invention is:
(A) hydrated metal oxide 10 to polyolefin resin
60% by weight, (B) nitric acid, sulfuric acid, polyphosphoric acid, boric acid,
(B) / (A) is obtained by adding 1 to 36% by weight of a salt of at least one inorganic acid selected from phosphorous acid and sulfurous acid and melamine.
+ B) is a flame-retardant resin composition characterized by having a ratio of 0.1 to 0.6.

In a second aspect, at least a part of the polyolefin resin is an ethylene-vinyl acetate copolymer,
(B) a salt of melamine with one or more inorganic acids selected from nitric acid, sulfuric acid, polyphosphoric acid, boric acid, phosphorous acid, and sulfurous acid;
The flame-retardant resin composition according to the first invention, which is melamine sulfate or melamine borate.

[0008] A third invention is a molded article using the flame-retardant resin composition according to the first invention or the second invention.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The polyolefin resin used in the present invention,
Ethylene, propylene, 1-butene, or other α
-Polymers such as olefins, these copolymers,
Includes blends. Further, a copolymer with another α-olefin, vinyl acetate, styrene, vinyl ether, maleic anhydride, carbon monoxide, N-vinyl carbazole, or the like may be used. Specific examples include polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer (EVA), ethylene-ethyl acrylate copolymer, and polyketone. In addition, those obtained by chemically reacting and modifying these polymers, specifically, ionomer resins, saponified EVA, and olefin elastomers produced using dynamic vulcanization in an extruder are also included. May be a mixture of the above resins.

[0010] Among these polymers, polyethylene, polypropylene and EVA are preferable because they have a good balance between mechanical strength and flame retardancy and can be applied to various uses. At least a part of the polyolefin resin is made of any of these resins. It is preferred that

EVA in the present invention is obtained by copolymerizing ethylene and vinyl acetate. If the vinyl acetate content is less than 15% by weight, the hardness of the molded product tends to increase, and the balance between flame retardancy, mechanical properties and flexibility is increased.
If it is more than 0% by weight, the mechanical properties tend to decrease. Therefore, the vinyl acetate content is preferably 15 to 30% by weight.

[0012] The hydrated metal oxide (A) used in the present invention is dehydrated by dehydration of adsorbed water or a chemical reaction in a combustion test or in a fire, and a combustible gas generated from the resin composition is diluted with water vapor. The endothermic reaction lowers the combustion temperature.

Specific examples include aluminum hydroxide, magnesium hydroxide, calcium hydroxide, tin hydroxide and the like. Among them, magnesium hydroxide has a dehydration temperature of 3
The temperature is 40 to 350 ° C., which is preferable because dehydration and endothermic reaction occur during combustion without dehydration due to heat during resin processing.

The hydrated metal oxide (A) is usually used as a powder having a particle size of 0.1 to 10 μm. Particle size 0.1
If it is smaller than μm, poor dispersion is likely to occur during melting and kneading with the resin, and it is difficult to obtain a flame retardant effect. On the other hand, when it is larger than 10 μm, the particles are easily conspicuous in the resin composition, and significantly impair the appearance. In addition, these materials improve the dispersibility in the resin, in order to easily exhibit an excellent flame retardant effect,
Surface treatment with a fatty acid, a fatty acid metal soap, a silane coupling agent, or the like, a metal soap such as magnesium stearate, or a dispersant such as polyethylene wax may be used in advance.

The amount of the hydrated metal oxide (A) to be added to the flame-retardant resin composition is preferably from 10 to 60% by weight. If it is less than 10% by weight, the flame retardant effect cannot be obtained, and if it exceeds 60% by weight, the mechanical properties deteriorate.

The (B) salt of melamine with one or more inorganic acids selected from nitric acid, sulfuric acid, polyphosphoric acid, boric acid, phosphorous acid and sulfurous acid used in the present invention is obtained by converting melamine having basicity to the above-mentioned inorganic acid. It is a melamine salt neutralized with an acid, and one or two or more salts may be used in combination.
(B) is obtained by introducing melamine into water, adding a calculated amount of an inorganic acid, heating and reacting, filtering, drying and pulverizing.

(B) shows that the solubility in water is smaller, the flame retardancy and the appearance are lower, from the viewpoint of application to actual use conditions, for example, the problem of dew condensation on wallpaper and the like, and the weather resistance when electric wires are used outdoors. Is good. Melamine sulfate and melamine borate are preferred from the standpoint of improving flame retardancy. Melamine sulfate is particularly preferred because of its excellent flame retardancy and low solubility in water.

The blending amount of (B) in the flame-retardant resin composition is as follows:
1 to 36% by weight is preferred. If the amount is less than 1% by weight, the flame retardant effect cannot be obtained, and if it exceeds 36% by weight, the mechanical properties deteriorate.

In the present invention, (A + B), that is, the amount of the flame retardant in the flame retardant resin composition is preferably from 10 to 65% by weight. If it is less than 10% by weight, the flame retardancy is insufficient,
If it exceeds 65% by weight, the physical properties of the resin may be significantly impaired. From the viewpoint of compatibility between flame retardancy and physical properties, (A + B)
Is particularly preferably 35 to 60% by weight.

Furthermore, in the present invention, the content of the components (A) and (B) is 0.1% when expressed as the value of (B) / (A + B).
When it is 0.6, an excellent flame retardant effect which is unexpected from the case where (A) and (B) are added alone can be obtained.
The ratio of (B) / (A + B) is less than 0.1 or 0.1.
If it is larger than 6, no improvement in flame retardancy is observed. When the ratio is 0.15 to 0.30, the flame retardancy is further increased, which is particularly preferable. In addition, since melamine salts are generally more expensive than hydrated metal oxides, it is more economical to have a lower content, and when the ratio is 0.15 to 0.25, the added amount and the effect corresponding to it are added. Is most preferable.

The flame-retardant resin composition of the present invention may contain, in addition to the above-mentioned components, various commonly used additives such as an antioxidant, an ultraviolet absorber, various dyes and pigments for coloring, a crosslinking agent, a crosslinking assistant, A foaming agent, a lubricant and the like can be contained, but in order to eliminate the generation of halogen gas, these additives must not contain a halogen element.
Also, other halogen-free flame retardants, such as red phosphorus,
Various metal salts and the like can be contained.

The flame-retardant resin composition of the present invention can be easily produced by melt-kneading the above components. Specific examples include a two-roll, a Banbury mixer, a kneader, and a twin-screw kneader. In addition, if the flame-retardant resin composition is a compound as it is, in the case of a master batch, it is appropriately diluted with a polyolefin-based resin to obtain a desired flame-retardant concentration, and the molding is performed using an extruder, an injection molding machine, or the like. , And molded products. Examples of molded articles include electric wires, automotive interior materials, films for building materials, and electric components.

[0023]

The present invention will be described below with reference to examples. Examples 1 to 6 and Comparative Examples 1 to 4 EVA: Evaflex 360 (manufactured by Mitsui Dupont Polychemical Co., Ltd.) Low density polyethylene (LDPE): Mirason 11P (manufactured by Mitsui Petrochemical Co., Ltd.) Mg (OH) ₂ : Kisuma 5B (manufactured by Kyowa Chemical Industry Co., Ltd.) Melamine sulfate: Avinone 901 (manufactured by Sanwa Chemical Co., Ltd.) Melamine cyanurate: MC-610 (manufactured by Nissan Chemical Co., Ltd.) Magnesium stearate: NP-1500 (manufactured by Tannan Chemical Co., Ltd.) ) The above components were mixed in the amounts (% by weight) shown in Table 1 and
The mixture was melt-kneaded with two rolls set at 40 ° C. for 5 minutes, and a plate-like sample was prepared from the obtained flame-retardant resin composition by hot pressing at 180 ° C. According to JIS K 7201
The oxygen index of this plate-like sample was measured. The results are shown in Table 1.

[0024]

[Table 1]

From the results of Comparative Example 1 and Examples 1 to 3, the flame retardant effect by adding melamine sulfate was confirmed. Further, from the results of Comparative Examples 2 and 3 and Examples 4 to 6, the flame retardant effect was obtained also by adding melamine sulfate to EVA, and particularly in Example 5, it was expected from the content of magnesium hydroxide and melamine sulfate alone. Significant improvement in the oxygen index that could not be obtained was confirmed. From the results of Comparative Example 4, it was understood that a melamine salt of an inorganic acid had a higher effect of improving the oxygen index than a melamine salt other than the inorganic acid.

[0026]

The flame-retardant resin composition containing no halogen element of the present invention has excellent flame retardancy, and is extremely effective as a molded article such as an electric wire, an automobile interior material, a building material film, and an electric component. is there.

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Claims (3)

[Claims] 1. A polyolefin resin comprising (A) 10 to 60% by weight of a hydrated metal oxide and (B) at least one inorganic material selected from nitric acid, sulfuric acid, polyphosphoric acid, boric acid, phosphorous acid and sulfurous acid. 1 to 36% by weight of salt of acid and melamine is added,
A flame-retardant resin composition, wherein the ratio of (B) / (A + B) is 0.1 to 0.6. (2) at least a part of the polyolefin resin is an ethylene-vinyl acetate copolymer, and (B) one or more inorganic acids selected from nitric acid, sulfuric acid, polyphosphoric acid, boric acid, phosphorous acid, and sulfurous acid The flame-retardant resin composition according to claim 1, wherein the salt of melamine and melamine is melamine sulfate or melamine borate. 3. A molded article comprising the flame-retardant resin composition according to claim 1 or 2.