JPS6013832A - Flame-retardant ethylene-ethyl acrylate copolymer composition - Google Patents

Abstract

PURPOSE:To provide the titled composition having remarkably improved flame retardancy keeping high insulation resistance and extrusion moldability, by compounding a hydrated magnesium and red phosphorus homogeneously to a base resin. CONSTITUTION:The objective composition is obtained by compounding (A) 100pts.wt. of an ethylene-ethyl acrylate copolymer homogeneously with (B) 50- 400pts.wt., preferably 50-200pts.wt. of a hydrated magnesium and (C) 1-30pts. wt., preferably 5-20pts.wt. of red phosphorus. The ethylene-ethyl acrylate copolymer is preferably the one having an MI of <=4 and an ethyl acrylate content of >=14wt%, and the hydrated magnesium is preferably magnesium hydroxide surface-treated with a higher fatty acid, a silane coupling agent, etc. The particle diameter of the red phosphorus is preferably <=10mu.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a flame-retardant ethylene-ethyl acrylate copolymer composition, in particular a flame-retardant ethylene-ethyl acrylate copolymer composition that maintains high insulation resistance and has low pollution and flame retardancy. 1. Regarding the ethyl acrylate copolymer composition.

Conventionally, as insulating compositions for the purpose of flame retardation, those made by blending various flame retardants with polyolefin copolymers are known. These flame retardants can be broadly classified into (() halogen type) and (b) inorganic type. Part 2.

Therefore, the flame retardant effect due to the combination of these flame retardants is (a)
Since the halogen flame retardant has a much higher value and is effective even when added in small amounts, the degree of decrease in insulation resistance and mechanical strength due to the addition of the flame retardant is also small.

However, in recent years, low-pollution properties have been proposed for insulating materials such as electric wires, and (a) halogen-based flame retardants are disadvantageous because they generate harmful gases such as hydrogen chlorides and smoke when burned. - 10,000, (b) Inorganic flame retardants do not generate harmful gases when burned, and are advantageous in terms of pollution.

(b) Inorganic flame retardants include magnesium hydroxide, aluminum hydroxide, zinc borate, antimony trioxide, etc., and systems in which one or more of them are blended with the IJ olefin copolymer are known. ing.

However, problems with these conventional techniques include, for example, when pairing an ethylene-vinyl acetate copolymer,
Compositions containing inorganic hydrates such as aluminum hydroxide and magnesium hydroxide have the ability to provide a high level of flame retardancy due to their synergistic effect! .

Poor electrical insulation resistance. Furthermore, when trying to improve properties by crosslinking, ethylene-vinyl acetate copolymers pose problems in extrusion processability in silane crosslinking systems, and in electron beam irradiation crosslinking systems, ethylene-vinyl acetate copolymers decompose due to irradiation. This causes a decrease in electrical insulation resistance and thermal stability.

10,000, blending systems with resins such as polyethylene, polypropylene, ethylene-globylene copolymers, linear low-density polyethylene, and ethylene-ethyl acrylate copolymers, which have excellent electrical insulation resistance, and inorganic hydrates are , there is no synergistic effect regarding flame retardancy, and a high level of flame retardancy cannot be obtained.

As described above, conventional flame retardant compositions of this type have both advantages and disadvantages and lack a definitive solution.

In view of this, the purpose of the present invention is to maintain low pollution and high electrical insulation resistance, and have excellent flame retardancy, and to improve extrusion processability in silane crosslinking systems, and to improve extrusion processability in electron beam irradiation crosslinking systems. The object of the present invention is to develop a composition that can prevent a decrease in electrical insulation resistance.

As a result of extensive research, the present inventors have discovered that among resins that provide high electrical insulation, only ethylene-ethyl acrylate copolymer exhibits unique behavior in terms of flame retardancy. That is, the flame retardant composition of the present invention was found to provide high flame retardancy only in a system consisting of an ethylene-ethyl acrylate copolymer, magnesium hydrate, particularly magnesium hydroxide, and red phosphorus. The product is characterized in that 50 to 400 parts by weight of magnesium hydrate and 1 to 30 parts by weight of red phosphorus are uniformly blended with 100 parts by weight of ethylene-ethyl acrylate copolymer.

Therefore, the ethylene-ethyl acrylate copolymer used in the present invention preferably has an MI of 24 or less and an ethyl acrylate content of 15 or more by weight.

In addition, magnesium hydrates include magnesium hydroxide, magnesium carbonate, and dolomite (magnesium carbonate +
Calcium carbonate], Hydrotalcite (Mg, A
~(OH), 8CO8.8.5 H2O], etc. can be used, but magnesium hydroxide is most desirable in consideration of the amount of water generated during combustion. In addition, since magnesium hydrate is hydrophilic, it has poor dispersibility and compatibility with resins, and has problems with crosslinking and processability.

It is preferable to use a surface treatment agent such as a ring agent to make the surface hydrophobic.

Regarding red phosphorus, any red phosphorus can be used as long as it can be mixed with the resin, and the particle size is preferably 1 (μ) or less in order to provide good dispersibility.

Note that the amount of magnesium hydrate is ethylene-
50 parts by weight of ethyl acrylate copolymer
~400 parts by weight, preferably il'' This is because the pressure inside the extruder will increase when extruding into electric wires, etc., and if the composition is cross-linked, it will exceed 2.
00 parts by weight or less, and 400 parts by weight or less for the uncrosslinked type, which is desirable considering the extrudability of the resulting composition. The amount is 1 to 30 parts by weight, preferably 5 to 20 parts by weight, based on 100 parts by weight of the polymer. When even a small amount of red phosphorus is added, the flame retardant effect of the composition suddenly improves, and the effect increases as the amount added increases, but the effect levels off above a certain amount. The amount varies depending on the amount of magnesium hydrate blended, but within the range of the amount of magnesium hydrate described above, C.
If the amount is 0 parts by weight or less, it will pass the VW-1 flame retardant test of the UL standard. Further, as the amount of red phosphorus increases, the pressure inside the extruder increases during extrusion coating on electric wires, etc., so the amount of red phosphorus is preferably 80 parts by weight or less, considering extrusion processability.

The flame retardant composition of the present invention may contain various heat stabilizers, lubricants,
Even if a crosslinking agent and a crosslinking accelerator are used in combination, the flame retardant effect will not be affected at the above compounding ratio.The mixing method for the 0 or 1 valley bottom portion is also not limited;
It is possible to use an open roll, mixing type extruder, etc.

According to the present invention, a flame retardant resin composition with a higher level than the conventional systems with inorganic flame retardants can be found. A phenomenon such as a decrease in electrical insulation resistance due to electron beam irradiation in the system does not occur with heathered yarn.

Below, we will compare the invention with the comparative example with respect to the examples.
I'll tell you my brother.

Examples 1 to 6 and Comparative Examples 1 to 9 are shown in Table 1, and Examples 7 to 9 are shown in Table 1.
9 and Comparative Examples 10 to 12 are shown in Table 2, and Example 1
．． 0 to 12 and Comparative Examples 13 to 14f: Listed in Table 3. The explanation in each table is as follows.

(a) The ethylene-ethyl acrylate copolymer has an ethyl acrylate content of 35% by weight, and has a product name of MB780 manufactured by Nippon Unicar Co., Ltd. (for example, Example 1) and an ethylene-ethyl acrylate copolymer with an ethyl acrylate content of 35% by weight. and the product name BRT 49θ manufactured by Nippon Unicar Co., Ltd. (for example, Example 5).

(b) The ethylene-vinyl acetate copolymer has a vinyl acetate content of 28% by weight and is manufactured by Mitsui Polychemical Co., Ltd. under the trade name Evaflex EV260.2. .

(e.g., Comparative Example 4) The ethylene-propylene copolymer has a propylene content of 49% by weight, and is manufactured by Japan Synthetic Rubber Co., Ltd. under the trade name EP-11 (e.g., Comparative Example 8). represent.

) The linear low-density polyethylene is manufactured by DuPont de Canada under the trade name Sflare 44H (for example, Comparative Example 9).
represents.

(e) Magnesium hydroxide is Kisuma 5A (trade name) manufactured by Kyowa Kagaku Co., Ltd. (for example, Example 1).

(f) Aluminum hydroxide is manufactured by Showa Light Metal Co., Ltd. under the trade name Heijirai) H-42-M (for example, Comparative Example 3).
).

(g) Red phosphorus is the one manufactured by Rin Kagaku Kogyo Co., Ltd. under the trade name Noballet 120UF (for example, Example 1). (7) Vinyltrimethoxysilane is the one manufactured by Tone Silicone Co., Ltd. under the trade name 5Z6800 ( For example, Comparative Example 10) is shown.

(Yuu dicumyl peroxide is manufactured by Mitsui Petrochemical Co., Ltd. under the trade name Mitsui Ri, O, P (for example, Comparative Example 10)
represents.

(b) Judgment of passing the *IVW-1 combustion test in Table 1 is when the afterflame time is within 60 seconds and the combustion length is 254 or less and self-extinguishing occurs. For this judgment in Table 1, a pass is indicated by a circle, and a fail is indicated by an X mark.

(c) Comparative Examples 1 to 9 and Examples 1 to 6, that is, the first
In the case of the products shown in the table, each ingredient is mixed with an open roll, the mixture is made into pellets with a pelletizer, and then
Extruder (L//D-24, set temperature 160°C, screw rotation speed 10,100 rpm, wire shape (conductor: O, S
S copper single wire, finished outer diameter 2.1 $). The above-mentioned VW-1 combustion test specified by UL Sub758-G was conducted on each of the wire samples.

2) Using the pellets from above Q), use an open roll to make a square sheet 14 with a side of 100 mm and a thickness of 1 JIS.
The electrical insulation resistance was measured according to K-6760 (measurement temperature: 20° C.).

(W) As is clear from Table 1, high flame retardance of VW-1 flame retardance level, which was not obtained in Comparative Examples 1 to 5 and 7 to 9, was obtained in Examples 1 to 6, and Example-6 is V
Although it passed the W-1 test, the electrical insulation resistance was 1015 or less, which is required for an insulated wire, whereas Examples 1 to 6 showed an electrical insulation resistance of 1016 or more.

(Kari) Next, various properties in the crosslinked system are shown in Comparative Example 1O in Table 2.
to 12, and Examples 7 to 9. The extrusion conditions for this Table 2 are: L/D=28 extruder, set temperature 160°
Extrusion molding was carried out using a C1 screw at a rotation speed of 3 o rpm.

(Y) In Table 2, Comparative Examples 1O to 12 of the ethylene-vinyl acetate copolymer system and the aluminum hydroxide system had a lot of foaming during extrusion and had poor appearance.
Examples 7 to 9 of the yarns of the present invention had good extrusion processability.

9) In Table 8, in Comparative Examples 18 to 14 of the ethylene-vinyl acetate copolymer system, the electrical insulation resistance decreased due to electron beam irradiation, but in Examples 10 to 12, the electrical insulation resistance decreased. There wasn't.

As is clear from the examples above, the flame-retardant ethylene-ethyl acrylate copolymer composition of the present invention is harmless, smokeless, and has high flammability at the VW-1 flame retardant level, and has an electrical insulation resistance. It also has a high value of 5 x 1014 Ω-1 or more, and there is no decrease in electrical insulation resistance due to crosslinking caused by electron beam irradiation, which is seen in ethylene-vinyl acetate copolymers and the like. Furthermore, it has excellent caroe properties during extrusion molding using the silane crosslinking method.

Continuation of page 1 0 shots clear person Hiroshi Hiruyo Hiratsuka Kuruma Norihachiman 5-1-9 Furukawa Electric Hiratsuka Electric Wire Manufacturing Co., Ltd. Inside 0 shots clear person Hidemi Nishiyama Hiratsuka Kuruma Norihachiman 5-1-9 Furukawa Electric Hiratsuka Electric Wire Manufacturing Co., Ltd.

Claims (1)

[Claims] 50 to 400 parts by weight of magnesium hydrate per 100 parts by weight of L ethylene-ethyl acrylate copolymer,
1. A flame-retardant ethylene-ethyl acrylate copolymer composition characterized by uniformly blending 1 to 80 parts by weight of red phosphorus.