JP2868875B2 - Flame retardant polymer composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a flame-retardant polymer composition. More particularly, the present invention relates to an improved flame-retardant polymer composition based on an olefin polymer suitable for a sheath of an electric wire, a cable or the like.

[Prior Art] Olefin polymers are widely used as electrical insulating materials because of their generally excellent electrical properties, mechanical properties, workability, and the like.

Particularly for applications such as electric wires and cables, copolymers of olefins and other monomers and / or modified olefin polymers obtained by graft modification, etc., for improving physical properties such as strength, low-temperature properties, scratch resistance, hardness, etc. Is used. Since such an olefin polymer or a modified olefin polymer is flammable, it is necessary to make it flame-retardant depending on the use. As a prescription for this purpose, there is a method of adding a halogen-based flame retardant such as a chlorinated product or a bromide product. For this reason, in recent years, methods using inorganic hydroxide flame retardants such as magnesium hydroxide and aluminum hydroxide have been widely studied. However, such inorganic hydroxides have a limited amount to be added due to restrictions on workability and other various physical properties, and depending on the simple use of the inorganic hydroxide, the flame retardancy is increased to a satisfactory degree by simple use. I couldn't do that.

In order to remedy such drawbacks, a number of methods using a combination of various additives have been proposed, but satisfactory results have not always been obtained.

The reason for this is not that simply improving the flame retardancy for the sheathing of wires and cables is not a matter of workability,
With respect to tensile properties, low-temperature embrittlement properties, heat resistance, flex whitening resistance, abrasion resistance, acid resistance, etc., it is necessary to increase flame retardancy while maintaining a certain level, which involves technical difficulties. Was.

In addition, the improvement in safety against combustion by the addition of such a flame retardant, that is, the efficiency of improving the flame retardancy and the phenomenon of fire sagging during combustion may differ significantly depending on the type of polymer to be applied. For the first time, an excellent flame-retardant polymer composition can be obtained by the combination of the polymer and the additive.

For example, a flame-retardant polyolefin resin composition in which a water-containing inorganic compound such as aluminum hydroxide or magnesium hydroxide and zinc carbonate are blended with a polyolefin resin has been proposed (JP-A-54-28347). It has been reported that flame retardancy is imparted by adding such additives in combination to an olefin polymer such as a copolymer or a copolymer of olefins. However, such a flame retardant cannot be said to have a sufficient effect of imparting flame retardancy to all olefin-based resins, and when applied to a modified olefin polymer such as used for electric cables, the processability is poor. Higher flame retardancy without compromising mechanical strength, such as US UL-94
(Underwriters Volatility) V-0
Reaching the level was not easy.

[Problems to be Solved by the Invention] The present inventors applied the modified polyolefin to processability,
As a result of examining the search for a flame retardant that meets the UL-94 standard without substantially impairing the mechanical strength, a hydroxyl-containing compound of magnesium and / or aluminum,
It has been found that the object can be achieved by adding zinc carbonate or borate and silicon oil in combination.

Accordingly, an object of the present invention is to provide a modified polymer composition having excellent mechanical properties and processability and further improved flame retardancy.

[Means for Solving the Problems] The present invention relates to an ethylene / (meth) acrylate copolymer 40 to 95% by weight and ethylene / (meth) acrylic acid copolymer partially or entirely graft-modified with an unsaturated carboxylic acid or an anhydride thereof. α-
Polymer component 10 consisting of 5 to 60% by weight of olefin copolymer
Flame retardancy obtained by mixing 50 to 200 parts by weight of a hydroxyl group-containing compound of magnesium and / or aluminum, 1 to 30 parts by weight of a carbonate or borate of zinc, and 0.1 to 20 parts by weight of silicone oil with respect to 0 parts by weight. It relates to a polymer composition.

In the present invention, as the polymer component, ethylene
An (meth) acrylic acid ester copolymer and an ethylene / α-olefin copolymer partially or wholly graft-modified with an unsaturated carboxylic acid or an anhydride thereof are used.

Examples of the ethylene / (meth) acrylic acid copolymer (here, the (meth) acrylic acid ester means an acrylic acid ester or a methacrylic acid ester) include, for example, an ethylene / (meth) acrylic acid methyl copolymer, Examples thereof include an ethyl (meth) acrylate copolymer and an ethylene / isobutyl methacrylate (meth) acrylate copolymer.

Such an ethylene / (meth) acrylate copolymer includes mechanical properties, processability,
In consideration of various properties such as flame retardancy, it is preferable to use methyl or ethyl ester as the (meth) acrylate component, and the ethylene content is 88 to 99 mol%, preferably 90 to 97%, ) An acrylate content of 1 to 12 mol%, preferably 3 to 10 mol%, and a melt flow rate (190 ° C., 2160 g load) of 0.1 to 200 g / 10
Min, preferably 0.1 to 30 g / 10 min.

An ethylene / α-olefin copolymer partially or wholly graft-modified with an unsaturated carboxylic acid or anhydride is a modified ethylene / α-olefin copolymer or a modified ethylene / α-olefin copolymer. It means a blend of ethylene / α-olefin copolymer, and the grafted unsaturated carboxylic acid or its anhydride is, for example,
It is present in a proportion of 0.05 to 5% by weight, preferably 0.1 to 3% by weight.

Here, as the α-olefin, propylene, 1-butene, 1-hexene, 1-octene, 1-decene, 4-
Methyl-1-pentene and the like can be exemplified. As an ethylene / α-olefin copolymer, high crystallinity,
May be of low crystalline or amorphous, for example a density crystallinity of 30% or more of the copolymers of 0.900~0.945g / cm ^3, or density of 0.900 g / cm ³ less than the crystallinity The copolymer may be less than 30%. Generally, it is preferable to use both copolymers in combination because of the tensile properties and low-temperature strength of the composition.

As the ethylene / α-olefin copolymer, those having a melt flow rate of 0.01 to 100 g / 10 minutes, particularly 1 to 10 g / 10 minutes, are preferred.

Examples of the unsaturated carboxylic acid or anhydride thereof serving as a graft component include fumaric acid, maleic acid, itaconic acid, acrylic acid, tetrahydrophthalic acid, nadic acid, maleic anhydride, and nadic acid anhydride.

The use ratio of the ethylene / (meth) acrylate copolymer and the ethylene / α-olefin copolymer partially or wholly graft-modified is 40 to 95% by weight, preferably 45 to 90% by weight of the former. The latter is 5 to 60% by weight, preferably 10 to 55% by weight. By using such a ratio, a composition having well-balanced tensile properties, low-temperature embrittlement properties, heat resistance, flex whitening resistance, scratch resistance, acid resistance, and the like can be obtained.

In addition to these two components, a small amount of an ethylene polymer or copolymer such as low-density polyethylene or ethylene-vinyl acetate copolymer may be blended.

One component of the flame retardant used in the present invention is a magnesium and / or aluminum hydroxide containing compound.
The magnesium or aluminum hydroxyl group-containing compound is a compound having at least one hydroxyl group per one atom of magnesium or aluminum, and more specifically, magnesium hydroxide, aluminum hydroxide, basic magnesium carbonate, hydrotalcite, and the like. Or a mixture of two or more selected from the group consisting of: These, of course,
They may be surface-treated with a silane coupling agent, a titanate coupling agent, a higher fatty acid or a salt thereof, a higher alcohol, a surfactant, etc., and these are used for dispersibility, workability, scratch resistance, and whitening resistance. It is preferable from the viewpoint of properties.
As the flame retardant, the average particle size is 20μ or less, especially 5μ
The following are preferred.

The amount of these hydroxyl group-containing compounds used is 100
The amount is 50 to 200 parts by weight, preferably 80 to 150 parts by weight, more preferably 110 to 145 parts by weight based on parts by weight.

In the present invention, a zinc carbonate or borate is added in addition to the hydroxyl group-containing compound. The zinc carbonate may be zinc carbonate or basic zinc carbonate. Among these zinc compounds, the use of carbonates is more preferable because the optimum addition width is wide or the amount of the hydroxyl group-containing compound used is effective even in a small range. The amount of the zinc compound is from 1 to 30 parts by weight, preferably from 5 to 20 parts by weight, per 100 parts by weight of the polymer component. In the case of zinc borate, the amount is preferably from 5 to 15 parts by weight. If the amount is too large, the mechanical strength, workability and the like are remarkably reduced. Of course, zinc carbonate or borate may be surface-treated, and the particle diameter is preferably 20 μm or less, particularly preferably 5 μm or less.

In the present invention, also per 100 parts by weight of the polymer component,
The total of the hydroxyl group-containing compound and the carbonate or borate of zinc is preferably from 120 to 160 parts by weight, particularly from 130 to 150 parts by weight, from the balance of the processability, mechanical strength and flame retardancy of the composition. .

To the composition of the present invention, silicone oil is added in addition to the above two inorganic flame retardant additives.

Silicon oil having various viscosities can be used. For example, silicone oil having a viscosity at 25 ° C. of 10 to 10,000 centistokes can be used. Needless to say, those having higher viscosity or those which are solid at room temperature can also be used. The silicone oil may be pure silicone oil or modified silicone oil such as fatty acid-modified silicone oil. Use of such a modified silicone oil is excellent in that it exudes to the polymer surface and is less sticky. The addition amount of the silicone oil is in the range of 0.1 to 20 parts by weight, preferably 1 to 10 parts by weight, per 100 parts by weight of the polymer component.

The composition of the present invention, in addition to the essential components, depending on the intended use, other flame retardants or flame retardant aids, antioxidants, heat stabilizers, antioxidants, ultraviolet absorbers, pigments, dyes, other An inorganic filler or the like can be blended. For example, carbon black, talc, clay, calcium carbonate, red phosphorus, phosphate ester and the like may be blended as a flame retardant aid.

The composition of the present invention can be produced by blending the above essential components and, if desired, additional components, and kneading them by a usual kneading method, for example, a Banbury mixer, a roll, a continuous kneading extruder or the like.

[Examples] Examples 1 to 7 Ethylene-ethyl acrylate copolymer (EEA) was partially or entirely graft-modified with an unsaturated carboxylic acid or an anhydride thereof as an ethylene (meth) acrylate copolymer. Graft-modified ethylene-butene-1 copolymer (graft-modified EBR), graft-modified linear low-density polyethylene (graft-modified LLDPE) as the ethylene / α-olefin copolymer, Using a mixture of unmodified EBR or LLDPE, and using magnesium hydroxide, basic zinc carbonate, zinc borate, and higher fatty acid-modified silicone oil as flame retardants, into a 6-inch roll at the mixing ratio shown in the upper column of Table 1. The mixture was charged and roll-kneaded to produce a flame-retardant polymer composition.

After kneading, a sheet having a thickness of 1 mm and 3 mm was formed by press molding, and was subjected to evaluation of tensile properties and flame retardancy.

Tensile properties were measured using a 1 mm thick press sheet, as specified in JIS K6301.
No. 3 test piece was measured according to JIS K6760. In addition, the flame retardancy is based on Underwriters Laboratories' safety standard U.
It was evaluated according to L94.

 The results are shown in the lower column of Table 1.

Comparative Examples 1 to 6 Flame-retardant polymer compositions were prepared in the same manner as in the Examples with the mixing ratios shown in the upper column of Table 2 and evaluated in the same manner. The results are shown in the lower column of Table 2.

The contents of the components shown in the table are as follows.

EEA: ethylene-ethyl acrylate copolymer with MFR 0.5 g / 10 min, ethyl acrylate content 15 wt% ethylene-ethyl acrylate copolymer with MFR 0.5 g / 10 min, ethyl acrylate content 25 wt% Graft modification EBR: MFR 3.6 g / 10 min, density 0.88 g / cm ³ ethylene-butene copolymer 100 parts by weight, maleic anhydride 0.55 parts by weight and organic peroxide (2,5-dimethyl-2,5-bis ( MFR 2.5 g / 10 obtained by subjecting 0.2 parts by weight of t-butylperoxy) hexane and brand name “Lupazole 101” to a melt reaction at 250 ° C. in an extruder.
Min, density of 0.88 g / cm ^3, maleic acid content of 0.5 wt% of maleic anhydride grafted ethylene anhydride - butene-1 copolymer graft modified LLDPE: MFR2.3g / 10 min, a density of 0.915 g / cm ³ Ethylene - Maleic anhydride 1 in 100 parts by weight of 4-methylpentene-1 copolymer
Parts by weight and an organic peroxide (2,5-dimethyl-2,5-bis (t
-Butyl peroxy) hexyne-3, 0.1 part by weight of brand name "Lupazole 130") was subjected to a melt reaction at 250 ° C. in an extruder at an MFR of 0.05 g / 10 minutes, a density of 0.915 g / cm ³ , and maleic anhydride. Maleic anhydride-grafted ethylene-4-methylpentene-1 copolymer having a content of 0.8% by weight EBR: ethylene-butene having a MFR of 3.6 g / 10 min and a density of 0.88 g / cm ³
1 Copolymer LLDPE: MFR 2.0 g / 10 min, density 0.910 g / cm ³ ethylene-4-methimepentene-1 copolymer Magnesium hydroxide: Kisuma 5A manufactured by Kyowa Chemical Co., Ltd. Basic zinc carbonate: transparent manufactured by Sakai Chemical Co. Zinc white Zinc borate: Reagent zinc borate manufactured by Kanto Chemical Co., Ltd. Higher fatty acid modified silicone oil: TSF410 manufactured by Toshiba Silicone Co., Ltd. As is clear from the results of Tables 1 and 2, the olefin polymer compositions of Examples 1 to 7 in which zinc carbonate or borate and silicone oil were used in combination with the flame retardant showed high flame retardancy. , UL94 VO was achieved. On the other hand, the compositions of Comparative Examples 1 to 6 in which zinc carbonate or borate was not added or in which no silicone oil was added had insufficient flame retardancy and could not achieve VO of UL94.

[Effect of the Invention] The flame-retardant polymer composition of the present invention is excellent in mechanical properties and processability, and can achieve high flame retardancy. That is, according to the present invention, a flame-retardant olefin polymer composition that reaches the level of VO in the UL standard can be easily obtained. Since the composition of the present invention does not generate toxic gas, corrosive gas or a large amount of smoke upon burning, it can be particularly suitably used as a coating material for electric wires and cables.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08L 83/04 C08L 83/04 H01B 3/44 H01B 3/44

Claims (1)

(57) [Claims] An ethylene / (meth) acrylic acid ester copolymer of 40 to 95% by weight and a part or all of which is graft-modified with an unsaturated carboxylic acid or an anhydride thereof.
Polymer component 10 consisting of 5 to 60% by weight of olefin copolymer
Flame retardancy obtained by mixing 50 to 200 parts by weight of a hydroxyl group-containing compound of magnesium and / or aluminum, 1 to 30 parts by weight of a carbonate or borate of zinc, and 0.1 to 20 parts by weight of silicone oil with respect to 0 parts by weight. Polymer composition.