JPS5879040A - Flame-retardant resin composition - Google Patents

Abstract

PURPOSE:A composition having high flame retardancy in spite of small amount of a metal oxide hydrate, keeping improved moldability and mechanical properties, obtained by blending a composition of a polyolefin resin and EVA with the metal oxide hydrate and a flame-retardant of the phosphoric acid type. CONSTITUTION:100pts.wt. composition consisting of 25-50pts.wt. polyolefin resin and 75-50pts.wt. ethylene-vinyl acetate copolymer is blended with 50-120pts.wt. hydrate of an inorganic metal compound (preferably one treated with silane, etc.) and 1-10pts.wt. flame-retardant of the phosphoric acid type. When the composition is blended with 2-30pts.wt. calcined clay or silica, the amount of the hydrate of the inorganic metal ocide can be reduced to 60-85pts.wt. and that of the flame-retardant of the phosphoric acid type can be reduced to 1- 5pts.wt.

Description

[Detailed description of the invention] This invention has excellent mechanical properties and moldability.

Moreover, the present invention relates to a flame-retardant polyolefin resin composition that does not generate harmful gases such as halogen gas during combustion.

Polyolefin resins have excellent electrical and mechanical properties and are inexpensive, so they are widely used as electrical insulating materials. However, this polyolefin resin has a serious drawback of being easily flammable, and for this reason, various types of fumigation have been carried out.

Currently, the most commonly used method is the combined use of halogenated flame retardants and antimony trioxide. However, although this method can impart extremely high flame retardancy,
A major problem is that it generates a large amount of chlorogen gas and smoke when burned. It goes without saying that halogen gas has a harmful effect on the human body, but its extremely corrosive nature also causes corrosion of surrounding equipment. For the following reasons, flame-retardant polyolefin-based fat compositions that do not generate halogen gas during combustion are desired.

To meet this requirement, for example, Japanese Patent Laid-Open No. 49-78
No. 741, 41 Publication No. 55-31871, JP-A [55-
There are flame-retardant compositions such as those shown in No. 34226. These flame retardant compositions are those in which large amounts of hydrated metal oxides such as aluminum hydroxide are added to 4-bore IJ and T-refine resins, and the flame retardant compositions disclosed in JP-A-49-78741 are The flammable composition is 100 parts by weight of wood @100 parts by weight.
-1100 parts by weight of a hydrated metal oxide is added, and in the case of the one disclosed in Japanese Patent Application Laid-Open No. 55-31871, 80 to 250 parts by weight of a hydrated metal oxide is added, and in the case of JP-A-55-34.
In the product shown in No. 226, an extremely large amount of 70 to 500 parts by weight is added. The reason why such a large amount of hydrated metal oxide is blended is that sufficient flame retardancy cannot be obtained unless a large amount of hydrated metal oxide is blended.

However, when such a large amount of hydrated metal oxide is blended into polyolefin resin, its mechanical properties and electrical properties deteriorate, as well as its moldability such as extrusion processability, making it difficult to use in actual use. The drawback was that the Kti was not durable.

This invention was made in consideration of the above circumstances, and has high flame retardancy and excellent moldability even though the amount of hydrated metal oxide added is small.

The object is to provide a flame retardant composition which also has mechanical and electrical properties.

The present invention will be described in detail below.

The flame-retardant resin composition of the present invention is a resin composition consisting of a polyolefin resin and an ethylene-vinyl acetate copolymer, and a hydrate of an inorganic metal oxide and a phosphoric acid flame retardant, if necessary. There is a Kame no F compounded with fired ray or silica.

As the polyolefin resin used in this invention,
Polyolefin homopolymers such as polyethylene (PK) and polypropylene (PP), ethylene propylene rubber (EPR), ionomers, polyolefin copolymers such as ethylene-ethyl acrylate copolymer (EAI), blend polymers of polyolefin polymers and other polymers, etc. The ethylene-vinyl acetate copolymer is not particularly limited, but one containing a vinyl acetate content of 5 to 40% by weight is usually used. What is the blending ratio of vinyl acetate copolymer?

The ethylene-vinyl acetate copolymer is used in an amount of 50 to 75 parts by weight per 1 sK of 11125 to 50 weight parts of the polyoleaine tree. If the ethylene-vinyl acetate copolymer is less than 50 parts by weight or exceeds 75 parts by weight, the compatibility with the inorganic metal oxide hydrate described below will decrease, making it impossible to obtain a uniform resin composition. .

This resin composition consisting of a polyolefin resin and an ethylene-vinyl acetate copolymer contains commonly used compounding agents such as anti-aging agents and vulcanizing agents.

A plasticizer, an antioxidant, a lubricant, an ultraviolet absorber, a colorant, an antistatic agent, etc. are added as needed in appropriate amounts.Next, this resin composition contains an inorganic metal oxide hydrate and phosphorus. An acid flame retardant is blended.

The hydrates of inorganic metal oxides used here include aluminum oxide hydrates (Al2O2.3H,O) and magnesium oxide hydrates (%0.2H!O). The crystalline water that is chemically bonded to the atoms is stable at the molding temperature of the resin composition.

Combustion source! It is the type that is released when a trap is reached.

This inorganic metal oxide hydrate can be blended into the resin composition as it is, but it can be surface-treated with K such as stearic acid, silane, borane, titanate, etc. to improve its affinity for the resin. The flame retardant effect of hydrated inorganic metal oxides is due to the endothermic action during the release of crystallized water. Not only does it not produce any gas, but it also has the effect of reducing the amount of smoke emitted during combustion.

The blending amount of the inorganic metal oxide hydrate is 50 to 120 parts by weight per 100 parts by weight of the resin content of the resin composition.
However, when calcined clay or silica is added as described below, the amount can be 60 to 85 parts by weight. If the amount is less than 50 parts by weight, the flame retardant effect will be lost, and if it exceeds 150 parts by weight, the moldability and mechanical properties of the resin composition will deteriorate.

In addition, as phosphoric acid-based fuels, phosphoric acid esters such as tricresyl phosphate (TCP), ) lith(β-chloroethyl) phosphate, tris(C dichloropropyl) phosphate, and tris(C dibromopropyl) phosphate are used. Although it is harmful, it is a tricresyl phosph that does not contain a halogen element in its molecule! -) (TCP) is the most preferred. This phosphoric acid flame retardant not only imparts excellent flame retardancy to resin compositions, but also plasticizes the composition and greatly improves molding processability such as extrusion processability. Improve. The blending amount of this phosphoric acid-based fuel agent is 1 to 10 parts by weight per 100 parts by weight of the resin in the resin composition, but when calcined clay or silica is added, it is 1 to 5 parts by weight. It is said that If the amount is less than 1 part by weight, the flame retardant effect and plasticizing effect will not be exhibited, and if it exceeds 10 parts by weight, the mechanical properties and electrical properties of the composition will deteriorate, which is undesirable.

As described above, by blending an inorganic metal oxide hydrate and a phosphoric acid flame retardant into a resin composition consisting of a polyolefin resin and an ethylene-vinyl acetate copolymer, the flame retardant composition of the present invention can be obtained. However, if necessary, it is possible to reduce the amount of inorganic metal oxide hydrate without reducing the flame retardancy by adding sintered clay or silica to this. This further improves engraving workability. The amount of baked clay or silica to be blended is 2 to 2 to 100 parts by weight of the resin composition.
30 parts by weight is preferred. If the blending amount is less than 2 parts by weight, the resulting resin composition will have insufficient flame retardancy, and if it exceeds 30 parts by weight, the molding processability will decrease, and mechanical properties will also deteriorate, which is disadvantageous. be. These fired lei,
Similar to hydrates of inorganic metal oxides, silica is preferably blended after surface treatment with silane, borane, titanate, stearic acid, etc.).

The thus obtained flame-retardant resin composition of the present invention is kneaded using a conventional Banbury mixer, Henschel mixer, kneader, roll, blender, etc., and then kneaded using an extruder, calender roll, injection molding machine, etc. Using a molding machine
It can be processed into film, sheet, pipe, or Fi-specific product forms, but compared to conventional compositions containing hydrates of inorganic metal oxides, the amount of hydrate blended is Due to the small amount and the addition of a phosphoric acid-based retardant, moldability is extremely high, and high-quality products can be manufactured with high efficiency. The flame-retardant composition obtained in this way is used in cables and chemicals for various power plants, including nuclear power plants, where the amount of corrosive gas is specified.

It is also suitable for use as cables for steel plants, fireproof electric wires, and general indoor wiring.

Hereinafter, the present invention will be specifically explained with reference to Examples.

[Example 1] A sheet with a thickness of 3 mm was prepared using the composition shown in Table 1 by a roll press method, and these sheets were given JI8-
The oxygen index using K-7201 was measured and the flame retardance was evaluated.An electric wire was manufactured using the same formulation and its extrusion processability and mechanical properties were evaluated. The results are also shown in Table 1.

[Example 2] Flame retardance 1 mechanical properties and extrusion processability of the compositions shown in Table 2 were evaluated in the same manner as in Example 1. The results are shown in Table 2.

As explained above, the flame retardant composition of the present invention includes a resin composition consisting of a polyolefin resin and an ethylene-vinyl acetate copolymer, a hydrate of an inorganic metal oxide, and a phosphoric acid flame retardant. Since a specific amount of fired clay or silica is blended depending on the conditions, high flame retardancy is achieved even though the amount of inorganic metal oxide hydrate blended is not small.

In addition, since the amount of the hydrate is small, the molding processability such as extrusion processability of the composition is improved, and the mechanical properties and electrical properties are excellent.

Furthermore, it has the advantage of not emitting any harmful halogen gas or the like during combustion. Therefore, the flame-retardant composition is suitable for flame-retardant electric wires, building materials, and the like.

Claims (1)

[Scope of Claims] 1. 50 to 120 parts by weight of a hydrate of an inorganic metal compound to 100 parts by weight of a resin composition consisting of 1125 to 50 parts by weight of a polyolefin tree 1j and 75 to 50 parts by weight of an ethylene-vinyl acetate copolymer. Parts by weight: Phosphoric acid flame retardant 1-10
A flame-retardant resin composition characterized by blending 2 parts by weight of a polyolefin fruit tree [1125 to 50 parts by weight and 75 to 50 parts by weight of an ethylene-vinyl acetate copolymer to 100 parts by weight] A flammable resin composition characterized by containing 50 to 85 parts by weight of a hydrate of an inorganic metal compound, 1 to 1 part by weight of a phosphoric acid flame retardant, and 2 to 30 parts by weight of calcined clay or silica. thing.