JPH0772240B2 - Abrasion resistant and flame retardant composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a flame-retardant composition which is highly crosslinkable, has excellent abrasion resistance in a highly crosslinked state, and has low pollution.

[Prior Art] Wiring work under harsh conditions as an edge wire covering material for electric wires, electric wires for vehicles, or electric wires for ships, which are wired inside electronic devices such as personal computers, electronic musical instruments, and microwave ovens. Also, it is required to have wear resistance so as to withstand normal operation and be flame-retardant.

[Problems to be solved by the invention]

By the way, many conventional flame-retardant compositions have a problem that a large amount of harmful halogen-containing gas is generated by combustion because they are flame-retarded by mixing a halogen-based flame retardant. Then, a halogen-free, in other words, a low-pollution flame-retardant composition is strongly required.

Therefore, for the reasons described above, a flame-retardant composition having abrasion resistance and low pollution is required, but the conventional flame-retardant composition does not always have sufficient performance in view of the above requirements. It is hard to say that you have it.

[Means for solving problems]

The present invention aims to provide a novel flame-retardant composition that satisfies the above-mentioned requirements.

That is, the present invention provides an ethylene-vinyl acetate having a melt index (MI) of 1.5 or less, a vinyl acetate (VA) content of 20% by weight or less, and a product of the melt index and the vinyl acetate content of 4 to 20. The copolymer and the ethylene-
The present invention relates to an abrasion-resistant and flame-retardant composition comprising 50 to 200 parts by weight of a halogen-free flame retardant per 100 parts by weight of a vinyl acetate copolymer and a crosslinking aid.

[Action]

The above ethylene-vinyl acetate copolymer is highly crosslinked even in the presence of a large amount of a non-halogen flame retardant, which will be described later, by crosslinking in the presence of a crosslinking aid, and in the highly crosslinked state. It has excellent wear resistance and flame retardancy.

Moreover, since the composition of the present invention employs a non-halogen-based flame retardant, it is halogen-free unless other chemicals containing halogen are blended, and therefore, even if it burns, it contains a halogen-containing gas. It does not cause any pollution.

The ethylene-vinyl acetate copolymer used in the present invention has a melt index of 1.5 or less, a vinyl acetate content of 20% by weight or less, and a product of the melt index and the vinyl acetate content of 4 to 20. Used. If the melt index is greater than 1.5, the mechanical strength and elongation will decrease significantly if a large amount of non-halogen flame retardant is mixed, and if the content of vinyl acetate is greater than 20% by weight, Even if cross-linked, the abrasion resistance is insufficient, and if the product of the melt index and the vinyl acetate content is out of the above range, either the mechanical properties or the abrasion resistance is insufficient. .

Therefore, the preferable ethylene-vinyl acetate copolymer used in the present invention has a melt index of 1.0 or less, a vinyl acetate content of 15% by weight or less, and a product of the melt index and the vinyl acetate content of 4 to 15%. belongs to.

Examples of the non-halogen flame retardant used in the present invention include alumina hydrates such as aluminum hydroxide, magnesium hydroxide, hydrates of metal oxides such as hydrotalcites, antimony trioxide, antimony pentoxide, and dioxide. Metal oxides such as titanium, zinc oxide, magnesium oxide, and aluminum oxide; other inorganic flame retardants such as zinc oxide and magnesium carbonate; and phosphorus-based organic flame retardants such as organic phosphate esters and red phosphorus. . As the red phosphorus, those commercially available in the past can be widely used, for example, the red phosphorus content is 80% by weight or more,
Loss on drying of 0.8% by weight or less and 74 mesh sieve residue is 7
It is preferably less than or equal to wt%. Further, it is also preferable that the surface of the above-mentioned red phosphorus is coated with a thermosetting resin such as phenol-formalin resin. Specific examples thereof include Novared # 120 and Novared # 120UF (both manufactured by Rin Kagaku Kogyo Co., Ltd.).

In the present invention, ethylene-vinyl acetate copolymer 100
The amount of non-halogen flame retardant used is 50 to 20 parts by weight.
0 parts by weight. When the amount of the non-halogen flame retardant used is less than 50 parts by weight, a composition having good wear resistance and flame retardancy cannot be obtained, while the amount of the non-halogen flame retardant used is 200 parts by weight. If the amount is larger, the mechanical properties and processability of the composition deteriorate. Therefore, the preferred amount of the non-halogen flame retardant used is 50 to 180 parts by weight, particularly 80 to 150 parts by weight, per 100 parts by weight of the ethylene-vinyl acetate copolymer.

The composition of the present invention comprises t-butyl cumyl peroxide,
Di-t-butyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy)
Cross-linking using an organic peroxide cross-linking agent such as hexane, 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3,1,3-bis (t-butylperoxy-isopropyl) benzene It can be crosslinked by a method, irradiation crosslinking method or the like. Therefore, as the crosslinking aid used in the present invention, those usually used in the above-mentioned crosslinking method may be used. Preferred cross-linking aids include aliphatic or aromatic polyfunctional compounds, aliphatic polyfunctional cyclic compounds, nitrogen-containing polyfunctional cyclic compounds, metal-containing polyfunctional compounds, and especially nitrogen-containing polyfunctional compounds. Functional cyclic compounds, especially triallyl isocyanurate (TAIC), trimetaallyl isocyanurate (TMAIC), triallyl cyanurate (TAIC)
C), triacroylhexahydro-1,3,5-triazine (TAF) and the like.

The amount of cross-linking aid used is 10% by weight of ethylene-vinyl acetate copolymer.
It is 0.1 to 5 parts by weight, especially 0.5 to 2 parts by weight, per 0 parts by weight.

In the present invention, when a small amount of a solid lubricant is blended in addition to the above flame retardant and crosslinking aid, the crosslinked molded article has good slipperiness and apparent wear resistance is improved. As the solid lubricant, waxes having a good compatibility with the ethylene-vinyl acetate copolymer such as polyethylene wax having a molecular weight of about 1000 to 3000 and montan wax ester wax are preferable, but they are inorganic lubricants such as molybdenum disulfide. Is also good. The blending amount of the solid lubricant is 0.1 to 10 parts by weight, particularly 0.5 to 5 parts by weight, per 100 parts by weight of the ethylene-vinyl acetate copolymer.

Further, silicone oil or the like may be thinly applied to the surface of the crosslinked molded article obtained from the composition of the present invention with or without a solid lubricant added thereto to improve the apparent wear resistance.

Clay, talc, calcium carbonate, carbon black and other inorganic fillers, antioxidants, coupling agents, processing aids, pigments, and other conventional compounding agents are added to the composition of the present invention in conventional amounts. But it doesn't matter.

〔effect〕

When electric wires, vehicle electric wires, or marine electric wires that are wired inside electronic devices such as personal computers, electronic musical instruments, and microwave ovens are narrow and are used in parts inside the device such as the maze, In many cases, it is subject to strong ironing, and after wiring, it is in a heated state and there is a risk of fire. On the other hand, since the composition of the present invention has both good wear resistance and flame retardancy, it is very useful as a covering material for electric wires such as in-device wiring, electric wires for vehicles, or electric wires for ships. .

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.

The compositions of various Examples and Comparative Examples shown in the attached table (composition ratio is parts by weight) were kneaded with two rolls, and then processed by press cure at 180 ° C. for 30 minutes to form a crosslinked sheet having a thickness of 1 mm or 3 mm. . The following tests were performed on each crosslinked sheet.

Flame retardance: Oxygen index is measured by the method specified in JIS K7201.

Abrasion resistance: Using a Taber abrasion tester, wear wheel: H-1
8, measured under the conditions of load: 1 kg, rotation speed: 1000 rpm.

The above test results are shown in the same table.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A 61-213214 (JP, A) JP-A 62-192435 (JP, A) JP-B 6-27225 (JP, B2)

Claims (6)

[Claims] 1. An ethylene-vinyl acetate copolymer having a melt index of 1.5 or less, a vinyl acetate content of 20% by weight or less, and a product of the melt index and the vinyl acetate content of 4 to 20, and the ethylene. -Vinyl acetate copolymer
A wear-resistant and flame-retardant composition comprising 50 to 200 parts by weight per 100 parts by weight of a non-halogen flame retardant and a crosslinking aid. 2. The abrasion-resistant and flame-retardant composition according to claim 1, wherein the non-halogen flame retardant is a hydrate of a metal oxide. 3. A hydrate of a metal oxide is a hydrate of alumina,
The wear-resistant and flame-retardant composition according to claim (2), which is magnesium hydroxide or hydrotalcites. 4. The abrasion-resistant and flame-retardant composition according to any one of claims (1) to (3), wherein the crosslinking aid is a nitrogen-containing polyfunctional cyclic compound. 5. The wear-resistant and flame-retardant composition according to any one of claims (1) to (4), which further contains a small amount of a solid lubricant. 6. The wear-resistant and flame-retardant composition according to claim 5, wherein the solid lubricant is polyethylene wax.