JPS61168644A - Flame-retardant resin composition - Google Patents

Abstract

PURPOSE:To increase the hardness of compsn. itself and to improve resistance to marring and wear when used as insulators or sheaths, by blending a specified quantity of a carboxyl group-contg. resin and a flame retarder composed of a water-contg. metallic compd. with an olefin resin. CONSTITUTION:An olefin resin (a), 1-50wt% (in terms of b/a+b) carboxyl group-contg. resin (b) and a flame retarder (c) composed of a water-contg. metallic compd. are blended together. Examples of the olefin resins are LDPE, HDPE and PP. Examples of the carboxyl group-contg. resins are ethylene/ methacrylic acid copolymer, ionomers and (meth)acrylic acid/styrene copolymer. Examples of the water-contg. metallic compds. are aluminum hydroxide, magnesium hydroxide and magnesium carbonate (MgCO3.nH2O).

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to a flame-retardant resin composition suitable for forming flame-retardant insulators and sheaths for electric wires, cables, etc.

[Prior art and its problems]

Traditionally, flame-retardant resin compositions used for such purposes include those made by adding antimony oxide and halides such as chlorinated paraffin to polyethylene, ethylene-acetate-vinyl copolymers, etc.; Aluminum (At(OR14), magnesium hydroxide (Mg(O
H)2) Magnesium carbonate (MgCO3・nHtQ
1 and other hydrated metal compounds are known.

However, in order to increase the flame retardancy of such a flame retardant resin composition to a level that passes UL standard VW-1 or IEEE 383, it is necessary to incorporate a large amount of flame retardant.

On the other hand, due to the toxicity and corrosivity of the combustion gas during combustion, compositions containing the above-mentioned hydrated metal compounds have recently been widely used, and such hydrated metal compounds are used as flame retardants in the compositions specified in the above standards. In order to obtain hazardous flame retardancy, the amount of water-containing metal compound in the composition will be 50wt4 or more.

However, when such flame retardants are highly loaded, the composition itself becomes soft when trying to maintain the mechanical strength, low-temperature properties, processability, and other properties of the composition at a certain level. There is a problem in that when the sheath is used, its trauma resistance and abrasion resistance decrease.

c. Elaborate means for solving the problem] Therefore, in the present invention, a water-containing metal compound is blended, and a resin containing a carboxyl group in the molecule is added to a part of the resin in the flame retardant resin composition. By using this, the hardness of the composition itself is increased and the above-mentioned problems are solved.

The flame retardant resin composition of the present invention contains an olefin resin, a resin containing a carboxyl group in the molecule, and a flame retardant made of a hydrous metal compound, and the resin composition contains a carboxyl group in the molecule based on the total amount of the above two resins. The ratio of 1 to 5 Qwt
4.

As the olefin resin, low density polyethylene (LD
PE 1, high-density polyethylene (HDPE 1, polypropylene (PP), ethylene-vinyl acetate co-te) (
F:VA>, ethylene/ethyl acrylate copolymer (1EEA), ethylene/α-olefin copolymer, and blend polymers thereof are used.

Examples of resins containing carboxyl groups in the molecule include ethylene/methacrylic acid copolymer/EMAA) and Ittumer resin, as well as unsaturated resins such as acrylic acid, methacrylic acid, maleic acid, and fumaric acid. Copolymers obtained by co-interpenetrating a polymer monomer with monomers such as styrene, vinyl acetate, and acrylic acid esters, and graft copolymers obtained by polymerizing the above-mentioned unsaturated acidic polymers with various polymers are used.

Then, the resin containing a carboxyl group in the molecule and the olefin resin are blended so that the resin containing a carboxyl group in the molecule is 1 to 50 wt%.

If the blending amount is less than 1 wt, the effect of improving the hardness of the composition described below cannot be obtained, and if it exceeds 5 Qwt, the mechanical strength frs will decrease, and the processability such as extrusion processing will also deteriorate, resulting in disadvantages. .

A flame-retardant agent made of a hydrous metal compound is added to the paceboomer IJmer having such a composition to obtain the desired flame-retardant resin composition.

As the hydrated metal compound, aluminum hydroxide (At
(OHI 3), magnesium hydroxide (Mg(OH+□
1. Magnesium carbonate l MgCO3.nH2O1, etc., thermally decomposes when heated, the bound water in the molecules evaporates, and the heat of evaporation produces a combustion effect.

The blending amount of this flame retardant is determined by the desired degree of flame retardancy t=X
However, the above-mentioned base 17? -1
It is possible to blend up to about 120 parts by weight with respect to 00ii parts, and it is possible to achieve UL -VW- by blending about 100 parts by weight.
It is possible to obtain flame retardancy specified by 1 and IEEE383.

A colorant, a stabilizer, a reinforcing agent, an antioxidant, a filler, etc. can be appropriately added to the above composition as required.

Then, this resin composition is kneaded by a conventional mixing means such as a high-speed stirrer or a mixing roll, and then made into resin molded products such as insulators and sheaths by using a molding machine such as an extrusion type.

[Effect]

In such a resin composition, by blending an appropriate amount of a resin containing a carboxyl group in the molecule, the hardness and rigidity of the composition are improved, and the trauma resistance and abrasion resistance are improved. Mechanical properties, low-temperature strength, workability, etc. are also improved.

The strength of the resin composition is improved due to the presence of force/I/in the molecule.
Carboxyl group of resin containing S
This is because it crosslinks with the metal of the J* water metal compound by ion feeding as described below, and exhibits behavior like a thermosetting resin at room temperature.

-c-c-c-c-c- ``On the other hand, at high temperatures, the ionic bonding force weakens] and it behaves like a normal thermoplastic resin.

[1! Experimental example] A soot fat composition with a formulation that meets the fx1 table was kneaded using a conventional method (YoQ) and extruded to make molded products.The tensile strength, elongation, workability, and trauma resistance of these molded products were evaluated. The abrasion resistance was measured.The results are also shown in Table 1.

Note that processability is an evaluation of extrusion processability. Regarding trauma resistance, a conductor with a diameter Q of 5suL was coated with a resin composition by extrusion to form an insulator with an outer diameter of 1.5JEjl.
When an insulated wire is run at a speed of 1250JLI/min in its longitudinal direction, and the right-angled edge of a triangular prism is pressed against the insulated wire from above perpendicular to the running direction with a load of 1Ic9, the insulator is scraped. 7t indicates that there is no peeling or cracking, and × indicates that there is no cracking. An insulated wire with an outer diameter of 1.5111 Jl was manufactured by extrusion coating in the same manner, and this was used as a sample to meet the U.S. military standard; MIL-543.
The results are shown below.

As is clear from the results in Table 1, EMAA is 1 to 5.
It can be seen that the compound containing Q wt 4 exhibits good mechanical properties and also has good processability, trauma resistance, and wear resistance. Similar results were obtained when hydrated magnesium was used as the hydrated metal compound.

〔Effect of the invention〕

As explained above, the flame-retardant resin composition of the present invention is
Contains a flame retardant consisting of an olefin resin, a resin containing a carboxyl group in the molecule, and a hydrous metal compound, and the ratio of the resin containing a carboxyl group in the molecule to the total amount of the above two resins is 1 to 5 Q wt 4. Therefore, even when a large amount of hydrated metal compound is blended in order to obtain high flame retardancy, the composition itself becomes hard due to the bond between the carboxyl group in the resin and the metal in the hydrated metal compound, resulting in poor trauma resistance. It has improved mechanical strength, electrical resistance, and workability, and is particularly suitable for use as insulators and sheaths for female flammable cables and cables. .

Claims (1)

[Claims] Contains an olefin resin, a resin containing a carboxyl group in the molecule, and a flame retardant made of a hydrous metal compound, and the amount of the resin containing a carboxyl group in the molecule relative to the total amount of the olefin resin and the resin containing a carboxyl group in the molecule. The ratio is 1
A flame-retardant resin composition characterized in that the content of the flame-retardant resin is 50 wt%.