JPH03197537A - Flame-retardant polymer composition - Google Patents

Abstract

PURPOSE:To prepare the title compsn. which markedly improve the oxygen index and shows no tackiness by compounding an olefinic polymer with specified amts. of a magnesium and/or aluminum compd. contg. OH groups and a specific silicone oil. CONSTITUTION:100 pts.wt. olefinic polymer [e.g. a mixture of an ethylene/ethyl acrylate copolymer, a (grafted) ethylene/1-butene copolymer, or an ethylene/4- methyl-1-pentene copolymer] is compounded with 50-200 pts.wt. magnesium and/or aluminum compd. contg. OH groups [e.g. Mg(OH)2] and 0.1-20 pts.wt. higher fatty acid-modified silicone oil (e.g. TSF 410, a product of Toshiba silicone Co.).

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.

[Prior art and its problems] Olefin polymers generally have poor electrical properties, mechanical properties,
Due to its excellent workability, it is widely used as an electrical feed line material, but it is easily flammable, so it may need to be made flame retardant depending on the application. 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 gas, corrosive gas, 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 have been widely studied. However, such inorganic hydroxides
Because there is a limit to the amount added due to constraints on processability and physical properties, it has not been possible to improve flame retardance to a satisfactory level by using only inorganic hydroxide.

In order to improve these drawbacks, many methods have been proposed in which various additives are used in combination. For example, the effectiveness of the method of adding silicone oil was demonstrated in JP-A-63-15.
It is known from Publication No. 9473. However, when using the silicone oil disclosed in this publication, although it has an additive effect, it is not easy to increase the flame retardance to a sufficiently satisfactory level, and the silicone oil oozes onto the surface of the molded product. However, it has the disadvantage that it tends to become sticky.

[Problems to be Solved by the Invention] As a result of intensive research aimed at improving the above-mentioned drawbacks of flame retardant formulations with the addition of inorganic hydroxide, the present inventors found that when a special silicone oil is used, low viscosity It was discovered that even if silicone oil is used, it does not ooze out onto the surface of the molded product and does not cause problems such as stickiness, and that even a small amount of silicone oil can significantly improve flame retardancy compared to ordinary silicone oil. This led to the present invention. Therefore, an object of the present invention is to provide a formulation that effectively improves flame retardancy using an inorganic hydroxide without substantially causing troubles such as stickiness on the surface of a molded article. Another object of the present invention is to provide a formulation that improves flame retardancy without impairing properties such as mechanical properties, flex whitening resistance, and processability.

[Means for Solving the Problems] The present invention provides the following methods: based on 100 parts by weight of an olefin polymer, magnesium and/or aluminum main polymer, ethylene/(meth)acrylic acid copolymer, ethylene/(meth)acrylic acid 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/(meth)ethyl acrylate copolymer, ethylene/(meth)acrylate copolymer
Isobutyl acrylate copolymer, ethylene/n-butyl (meth)acrylate copolymer, etc., ethylene/vinyl acetate/maleic anhydride copolymer, ethylene/(meth)acrylic acid/(meth)acrylic acid ester copolymer Examples include ethylene/(meth)acrylic acid ester/carbon oxide copolymers, and graft copolymers of maleic anhydride, himic acid, etc. using these polymers as the backbone polymer.

Although it varies depending on the purpose of use, for example, for coating purposes such as electric wires and cables, these olefinic acid group-containing compounds 50~
200 parts by weight and higher fatty acid modified silicone oil 0.1
This is a flame retardant polymer composition containing ~20 parts by weight.

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. Further, the copolymer may be a random copolymer, a block copolymer, a graft copolymer, or the like. Specifically, polyethylene, polypropylene, poly-1-butene, poly-
4-methyl-1-pentene, a copolymer of ethylene and a small proportion of other olefins, such as propylene, l-butene, l-hexene, 1-octene, 1-decene, 4-methyl-1-pentene, etc. Copolymers of propylene and small proportions of other olefins, such as ethylene, 1-butene, 1-hexene, etc., 1-butene copolymers, ethylene-propylene-diene copolymers, ethylene-vinyl acetate copolymers Low-crystalline or non-crystalline ethylene with a density of 0.89 g/cnf or less, which is partially or wholly graft-modified with an ethylene/(meth)acrylic acid ester copolymer and an unsaturated carboxylic acid or its anhydride. - It is preferred to use a blend of α-olefin copolymers.

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 it is 3 to 10 mol%, and the melt flow rate (190°C, 2160g load) is 0. 1-200g/10min, 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 modified ethylene/α-olefin copolymer or a modified ethylene/α-olefin copolymer and an unmodified ethylene・α
- means a blend of olefin copolymers, the grafted unsaturated carboxylic acid or its anhydride being e.g.
It is present in a proportion of ~5% by weight, preferably 1-3% by weight. Suitable ethylene/α-olefin copolymers serving as the backbone polymer include ethylene/propylene copolymers and ethylene/1-butene copolymers, with ethylene/l-butene copolymers being particularly preferred. The melt flow rate is o, i~100g/10 min, especially 1
~Log/10 minutes is preferred.

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
．． Ethylene/α-olefin copolymer, ethylene/vinyl acetate copolymer, etc. exceeding 89g/ctrl'
In the present invention, higher fatty acid-modified silicone oil is added to the two-component mixture in a proportion of not more than 5% by weight, preferably 5 to 30% by weight, in addition to the hydroxyl group-containing compound.

The main component of ordinary silicone oil is polydialkylpolysiloxane, and the terminals are also usually capped with trialkylsilyl groups, whereas the higher fatty acid-modified silicone oil used in the present invention has higher fatty acid ester substitution in the molecule. It has a silyl group (-8iR"0OCR).The most common type is polydimethylpolysiloxane whose terminal group or side chain methyl group is substituted with a higher fatty acid ester residue (-R'0OCR). (here, R is a saturated or unsaturated aliphatic hydrocarbon group such as a higher alkyl group or alkenyl group having 9 to 23 carbon atoms, and Ro represents an alkylene group having 1 to 10 carbon atoms. ).

As this modified silicone oil, it is possible to use those with various viscosities, and (low viscosity compositions are also available)
Suitable for the same purpose.

One component of the flame retardant used in the present invention is a magnesium and/or aluminum hydroxyl group-containing compound. 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 type or a mixture of two or more types selected from. Of course, these may be surface-treated with silane coupling agents, titanate coupling agents, higher fatty acids or their salts, higher alcohols, surfactants, etc. It is preferable from the viewpoint of scratch resistance and whitening resistance.The above flame retardant has an average particle size of 20μ or less, particularly 5μ
The following are preferred.

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

It is preferable to use one having a viscosity of, for example, 10 centistokes or more and 100,000 centistokes or less at 25° C., since even if a viscosity of 100,000 centistokes or less is used, there is little oozing to the surface of the molded product. Of course, those with higher viscosity or those that are solid at room temperature can also be used. Representative examples of such products include TSF410 (manufactured by Toshiba Silicone Co., Ltd.) and KF-910 (manufactured by Shin-Etsu Silicone Co., Ltd.), which are available on the market. The blending ratio of modified silicone oil is 100 parts by weight of olefin polymer,
The amount is 0.1 to 20 parts by weight, preferably 1 to 10 parts by weight. While this modified silicone oil is effective when added in a relatively small amount, no further effect can be expected if it is added in too large a quantity, and on the contrary, it will ooze out significantly and also impair mechanical properties and flame retardancy. It is necessary to use the amount as shown above.

In addition to the above-mentioned essential components, the composition of the present invention may contain other flame retardants or flame retardant aids, antioxidants, heat stabilizers, anti-aging agents, ultraviolet absorbers, pigments, dyes, and other additives depending on the purpose of use. Inorganic fillers and the like can be added. For example, carbon black, talc, clay, calcium carbonate, red phosphorus, phosphate ester, etc. may be blended as flame retardant aids.

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 mixing method, such as a Banbury mixer, a roll, or a continuous kneading extruder.

[Effects of the Invention] The flame-retardant polymer composition of the present invention has a greater effect of improving the oxygen index than systems containing general silicone oil such as polydimethylpolysiloxane, and also has a greater effect on improving the oxygen index on the surface of molded products. It has the advantage of not being sticky because there is little oozing. In addition, it achieves a high degree of flame retardancy without sacrificing mechanical properties or processability, and does not generate toxic or corrosive gas or large amounts of smoke when burned, making it particularly suitable as a coating material for electric wires, cables, etc. Can be used.

[Example〕 1 ma Evaluation was made based on the degree of heat. The results are shown in the lower column of Table 1.

Using the same four types of olefin polymers used in Comparative Medical Second and Examples,
One using general silicone oil instead of higher fatty acid-modified silicone oil as a flame retardant and one without silicone oil were kneaded using a 6-inch roll in the same manner as in the example at the blending ratio shown in the upper column of Table 1. Then, 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 1.

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

EEA: MFRo, 5 g/10 min, ethylene-ethyl acrylate copolymer with ethyl acrylate content 15% by weight EBR: MFR 3.6 g/10 min, density 0.88 g/c
Large Example of Ethylene-1-Butene Copolymer (d) As the niolefin polymer, ethylene-ethyl acrylate copolymer (EEA), ethylene-1-butene copolymer (E
BR), graft-modified EBR, and LLDPE, magnesium hydroxide and higher fatty acid-modified silicone oil as flame retardants, are put into a 6-inch roll at the mixing ratio shown in the upper column of Table 1, and kneaded by rolls to obtain flame retardant properties. An olefin polymer 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.

The 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 JIS K7201 using a press sheet with a thickness of 3 mm. Silicone oil oozes out when the surface of the sheet is touched with your hand after making a 1 mm thick press sheet and leaving it in a constant temperature room at 23°C and 50% relative humidity for more than 24 hours.2 Graft-modified EBR : To 100 parts by weight of the above EBR, 0.55 parts by weight of maleic anhydride and 0.2 parts by weight of an organic peroxide (2,5-di(t-butylperoxy)hexyne, brand name "Rubasol 101J)" were added in an extruder. MF R2, obtained by melt reaction at 250°C, 5g/10min, density 0.88g/cnf, maleic anhydride content 0.5% by weight
maleic anhydride grafted ethylene-1-butene copolymer.

LLDPE: MFR2, Og/10 min, density 0.910
g/cm of ethylene-4-methyl-1-pentene copolymer magnesium hydroxide: Kisuma 5A manufactured by Kyowa Chemical Co., Ltd. Higher fatty acid modified silicone oil: Higher fatty acid modified silicone oil with a viscosity of 30C3 at 25°C (TSF410 manufactured by Toshiba Silicone Co., Ltd.) Silicone oil: ■Polydimethylsiloxane oil with a viscosity of 5000C3 at 25°C (TSF 451 manufactured by Toshiba Silicone Co., Ltd.) ■Polydimethylsiloxane oil with a viscosity of 100,000C8 at 25°C (TSF451 manufactured by Toshiba Silicone Company) Below margins 5 Table 1 As is clear from the results, Example 1 in which higher fatty acid-modified silicone oil was used in the M refractor formulation exhibited high flame retardancy, and almost no oozing of silicone oil was observed. On the other hand, in Comparative Examples 1 and 2 in which polydimethylsiloxane oil was used as a general silicone oil, the flame retardance was lower than that of Example 1 (and significant oozing of silicone oil was observed).

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 0.0 parts by weight of higher fatty acid modified silicone oil.
A flame retardant polymer composition containing 1 to 20 parts by weight.