JPH0354236A - Flame-retardant polymer composition - Google Patents

Abstract

PURPOSE:To prepare a flame-retardant polymer compsn., being nonsticky and generating neither toxic nor corrosive gas when burned, by compounding an olefin polymer with specified amts. of a hydroxide of Mg and/or Al and a specific powdered silica. CONSTITUTION:100pts.wt. olefin polymer [e.g. a mixture of ethylene-ethyl acrylate copolymer, (grafted) ethylene-butene-1 copolymer, and ethylene-4- methylpentene-1 copolymer] is compounded with 50-200pts.wt. hydroxide of Mg and/or Al [e.g. Mg(OH)2] and 1-50pts.wt. powdered silica carrying a silicone oil in a high concn.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to flame-retardant polymer compositions. More particularly, the present invention relates to improved flame-retardant polymer compositions based on olefin polymers suitable for sheathing of electric wires, cables, etc.

[Conventional technology and its problems]

Olefin polymers generally have electrical properties, mechanical properties,
Due to its excellent workability, it is widely used as an electrical insulating material, but it is easily flammable, so it may need to be made flame retardant depending on its use. One way to do this is to add halogen flame retardants such as chlorides and bromides.
These halogen-based flame retardants have the disadvantage of emitting toxic gases, corrosive gases, and large amounts of smoke when burned, so in recent years, inorganic hydroxide flame retardants such as magnesium hydroxide and aluminum hydroxide have been used. Methods to do so are now being widely considered. However, such inorganic hydroxides
Because there is a limit to the amount added due to processability and other physical property constraints, it has not been possible to increase flame retardance to a satisfactory level by using a single inorganic hydroxide. In order to improve these drawbacks, many methods have been proposed in which various additives are used in combination. For example, formulations in which silicone oil, silica, etc. are added are known, and have shown some effectiveness. However, since silicone oil tends to ooze out onto the surface of the molded product and cause stickiness, it has the disadvantage that it cannot be added in large amounts, and the effect of adding silica has not been that great.

[Problems to be Solved by the Invention] The purpose of the present invention is to improve the above-mentioned drawbacks of flame retardant formulations containing inorganic hydroxide, and to effectively improve flame retardancy without causing quality problems such as stickiness. This is what we mean. Another object of the present invention is to provide a formulation that improves flame retardancy without impairing various properties such as mechanical properties, flex whitening resistance, and processability.

[Means to solve the problem]

The present invention is a flame retardant compound containing 100 parts by weight of an olefin polymer, 50 to 200 parts by weight of a magnesium and/or aluminum hydroxyl group-containing compound, and 1 to 50 parts by weight of powdered silica supporting a high concentration of silicone oil. It is a polymer composition. The olefin polymer used in the present invention is one or a mixture of two or more selected from olefin homopolymers, copolymers of olefins, and copolymers of olefins and monomers other than olefins. These may be highly crystalline, low crystalline or non-crystalline polymers. In addition, for copolymers, random copolymers,
It may also be a block copolymer, a graft copolymer, or the like. Specifically, polyethylene, polypropylene, poly-1
-butene, poly-4-methyl-1-bentene, ethylene and small proportions of other olefins, such as brobylene, 1-butene, -hexene, 1-octene, 1-decene, 4-
Copolymers with methyl-1-bentene etc., brobylene with small proportions of other olefins such as ethylene, 1-butene,
Copolymers with l-hexene etc., 1-butene copolymers, ethylene/brobylene/diene copolymers, ethylene/vinyl acetate copolymers, ethylene/(meth)acrylic acid copolymers, ethylene/(meth)acrylic acid copolymers Acrylic ester copolymers (herein, (meth)acrylic acid refers to acrylic acid or methacrylic acid, and (meth)acrylic ester refers to acrylic ester or methacrylic ester), such as ethylene (meth) Methyl acrylate copolymer, ethylene/ethyl (meth)acrylate copolymer, ethylene/isobutyl (meth)acrylate copolymer, ethylene/n-butyl (meth)acrylate copolymer, etc., ethylene/vinyl acetate・Maleic anhydride copolymer,
Ethylene/(meth)acrylic acid/(meth)acrylic acid ester copolymer, ethylene/(meth)acrylic acid ester/carbon monoxide copolymer, maleic anhydride, Himic acid, etc. using these polymers as the backbone polymer. Examples include graft copolymers and the like.

Although it varies depending on the purpose of use, for example, olefin polymers such as ethylene and (meth)acrylic ester are used for coating electric wires, cables, etc. from the viewpoint of strength, low-temperature properties, resistance to yellowing, acid resistance, etc. A blend of a polymer and a low-crystalline or non-crystalline ethylene/a-olefin copolymer having a density of 0.89 g/crn' or less and partially or wholly graft-modified with an unsaturated carboxylic acid or its anhydride. It is preferable to use

Such ethylene/(meth)acrylic acid ester copolymers include, for example, ethylene content of 88 to 99 mol%, preferably 90 to 97%, (meth)acrylic ester content of 1 to 12 mol%, Preferably 3 to 10 mol%, mel flow rate (190°C, 2160 g
load) is 0.1 to 200g/10 minutes, preferably 0.1
~30g/10 minutes can be used. An ethylene/α-olefin copolymer partially or wholly graft-modified with an unsaturated carboxylic acid or its anhydride is a combination of a modified ethylene α-olefin copolymer or a modified ethylene/α-olefin copolymer and an unmodified ethylene - means a blend of alpha-olefin copolymers, in which the grafted unsaturated carboxylic acid or its anhydride is, for example, O. 1-5
It is present in a proportion by weight, preferably from 0.1 to 3% by weight. Suitable ethylene/α-olefin copolymers to serve as the backbone polymer include ethylene/brobylene copolymers,
It is an ethylene/1-butene copolymer, and an ethylene/1-butene copolymer is particularly preferred. Moreover, the melt flow rate is 0.1-100g/10 minutes, especially 1-1
0 g/10 min is preferable.

The usage ratio of the ethylene/(meth)acrylic acid ester copolymer and the ethylene/α-olefin copolymer partially or wholly graft-modified is, for example, 20 to 90% by weight of the former, preferably 30 to 70% by weight. On the other hand, the latter 10~
80% by weight, preferably 30-70% by weight.

In addition to these two components, low density polyethylene, density 0
．． 89g/err? Ethylene/α-,1-lefin copolymer, ethylene/vinyl acetate copolymer, etc. exceeding 50%
Compositions added to the two-component mixture in proportions of up to 5% by weight, preferably from 5 to 30% by weight, are also suitable for the same purpose.

The flame retardant used in the present invention is a hydroxyl group-containing compound of magnicium and/or aluminum. The above magnesium or aluminum hydroxyl group-containing compound is a compound containing at least one hydroxyl group per 1 atom of magnesium or aluminum, and more specifically includes magnesium hydroxide, aluminum hydroxide, basic magnesium carbonate, hydrotalcite, etc. It is one kind or a mixture of two or more selected from. These materials may be surface-treated with silane coupling agents, titanate coupling agents, higher fatty acids or their salts, higher alcohols, W surfactants, etc., and their use improves dispersibility, processability, Preferable in terms of scratch resistance and whitening resistance. The above flame retardant preferably has an average particle size of 2OL1 or less, particularly 5μ or less.

In the present invention, in addition to the hydroxyl group-containing compound, powdered silica supporting silicone oil is used. The silicone oil is diorganoborisiloxane or a modified product thereof, and representative examples include dimethylborisiloxane, phenylmethylborisiloxane, etc. can be mentioned. As a silicone oil, the viscosity at 25℃ is 50 centimeters.
- 6 or more centistokes, preferably 1000 centistokes or more. These silicone oils are supported on powdered silica at a high concentration, for example, 30 to 80%, and are in the form of powder with good fluidity. This particle size is, for example, 1~
The particle size is 500μ. A typical example of such a product is Refill F200. F201, F202. F2
03,F250,F300 F301 F400
(manufactured by Torre Silicone).

The silicone oil-supported powdered silica used in the present invention has silicone oil supported on the silica in advance as described above, and although it contains a high concentration of silicone oil, it is powder-like and cannot be molded. Since there is no oozing of silicone oil to the extent that it causes stickiness on the product surface, it is possible to incorporate a large amount of silicone oil, and therefore flame retardance can be improved without deteriorating quality. This is a major feature of the present invention. Instead of using powdered silica that supports silicone oil, silicone oil is not supported on powdered silica.If it is blended with a refin-containing material, if the amount of silicone oil increases slightly, it will not adhere to the surface of the molded product. This is undesirable because it causes oozing.

The blending amount of each component is 50 to 200 parts by weight, preferably 80 to 1.50 parts by weight, of the hydroxyl group-containing compound per 100 parts by weight of the olefin polymer, and 1 to 1.5 parts by weight of the powdered silicone oil supported. 50 parts by weight, preferably 1-2
0-fold storm ξ11, ′−,ru. In addition to the above-mentioned essential components, the composition of the present invention may include other flame retardants or flame retardant aids, antioxidants, heat stabilizers, anti-aging agents, ultraviolet absorbers, pigments, dyes, etc. depending on the purpose of use. Other inorganic fillers etc. can be added. For example, carbon black as a flame retardant aid,
It contains talc, clay, calcium carbonate, red phosphorus, phosphate ester, etc.

The composition of the present invention can be produced by blending the above-mentioned essential components and optionally additional components, and kneading the mixture using a conventional kneading method, such as a Banbury mixer, a roll, or a continuous kneading extruder.

[Effects of the Invention] Although the flame-retardant polymer composition of the present invention contains silicone oil, the silicone oil does not ooze out and the surface of the molded product does not become sticky. Therefore, electric wires that exhibit significantly improved flame retardancy and do not emit toxic gases, corrosive gases, or large amounts of smoke when burned,
It is suitable as a cable covering material.

[Example] Ethyl L/ethyl acrylate copolymer (EEA) was used as the olefin polymer. Ethylene-butene-1 copolymer (
EBR). Four components, graft-modified EBR and LLDPE, and magnesium hydroxide and silicone oil-supported silica as flame retardants, were put into a 6-inch roll at the mixing ratio shown in the upper column of Table 1, and kneaded with a roll to form a flame-retardant olefin polymer. A combined composition was produced.

After cross-wiring, sheets with thicknesses of 1 mm and 3 mm were formed by press molding, and evaluated for tensile properties, oxygen index, and silicone oil exudation.

Tensile properties were measured using a press sheet with a thickness of 1 mm, and JIS
Measurement was performed using a No. 3 test piece of K6301 in accordance with JIS K6760. Further, the oxygen index was measured in accordance with JLSK7201 using a press sheet with a thickness of 3 mm. The oozing of silicone oil was determined by the degree of stickiness when touching the sheet surface with your hand after making a press sheet with a thickness of 1 mm and leaving it in a constant temperature and humidity room at 23°C and 50% relative humidity for more than 24 hours. Evaluated by. The results are shown in the lower column of Table 1.

Using the same four types of olefin polymers used in the example,
Using silicone oil instead of silicone oil-supported silica as a flame retardant and silicone oil at the blending ratio shown in the upper column of Table 1, the mixture was kneaded with a 6-inch roll in the same manner as in the example.
A flame-retardant olefin polymer sheet was prepared by press molding, and its physical properties were evaluated in the same manner as in the examples. The results are shown in the lower column of Table 2.

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

EEA: MFR 0.5 g/10 minutes, ethylene-ethyl acrylate copolymer with ethyl acrylate content 15% per day EBR: MFR 3.6 g/10 minutes. Density 0.88g
/cd of ethylene-butene-1 copolymerized graft-modified EBR: 0.55 parts by weight of maleic anhydride and an organic peroxide (2.5-di(t-butylbaroxy)hexyne, brand name) to the above EBRIOO parts by weight. MF R obtained by melting and reacting 0.2 parts by weight of Rubazol 101J at 250°C in an extruder, density 0288g/cr
d, maleic anhydride content 0. 5% by weight maleic anhydride grafted ethylene-butene-1 copolymer.

LLDPE: MFR 2. Og/10 min, density 0.9
10g/crrf of ethylene-4-methylbentene-1
Copolymer magnesium hydroxide: Kyowa Kagaku Co., Ltd. Kisuma 5A silicone oil-supported silica: ■ Silica fine powder supporting 60% by weight of highly polymerized polydimethylsiloxane oil with a viscosity of 100075-CS or higher at 25°C (Toray Silicone Co., Ltd.) TORAYFIL F400) Silicone oil: ■Teno viscosity at 25°C: 60,000 CS(+) Fine silica powder carrying 60% by weight of polydimethylsiloxane oil (TOREFIL F 202, manufactured by TORAY SILICONE CO., LTD.) Silicone oil: ■Viscosity at 25°C: 100,000 CS (+) polydimethylsiloxane oil Siloxane oil (S H 200 manufactured by Toray Silicone Co., Ltd.) Highly polymerized polydimethylsiloxane oil (c7 at 25T) u degree IQQO 75'cs or more (BY16-1.40 manufactured by Toray Silicone Co., Ltd.) Silica: Average particle size approximately 30 mμ Ultrafine powdered silica (AEROSI L MOX80 manufactured by Nippon Aerosil Co., Ltd.) Table 1 As is clear from the results in Table 1, Examples 1 to 5 in which Sinocon oil-supported silica was used in the flame retardant formulation had high flame retardancy. , and almost no silicone oil oozed out. Comparative example 1 using silicone oil
~3, a remarkable increase in silicone oil was seen.

Also, in Comparative Example 4 in which silicone oil and silica were separately blended, no improvement in silicone oil oozing was observed. Moreover, magnesium hydroxide/silica or magnesium hydroxide alone does not have a sufficient flame retardant improvement effect.

Claims (1)

[Claims] (1) 50 parts of magnesium and/or aluminum hydroxyl group-containing compound per 100 parts by weight of olefin polymer
~200 parts by weight and 1 to 50 parts by weight of powdered silica carrying silicone oil at a high concentration.