JP2007070483A - Flame-retardant composition for coating of electric wire/cable and flame-retardant electric wire/cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a halogen-free flame-retardant composition for the coating of an electric wire/cable, having excellent flame-retardancy and good mechanical properties such as tensile strength and provide a flame-retardant electric wire/cable produced by using the flame-retardant composition. <P>SOLUTION: The halogen-free flame-retardant composition for the coating of an electric wire/cable and composed mainly of an ethylenic polymer contains (a) 30-100 pts.wt. of a metal hydroxide and (b) 1-10 pts.wt. of a nano-sized clay in 100 pts.wt. of an ethylenic polymer. The invention further provides a flame-retardant electric wire/cable having a coating layer composed of the composition. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a non-halogen flame retardant composition for covering electric wires and cables and a flame retardant electric wire and cable having high environmental conservation using the same.

  Polyvinyl chloride (PVC) has relatively good insulation properties and is excellent in flame retardancy because it contains halogen (Cl) in the molecule. Furthermore, it has oil resistance, ozone resistance, chemical resistance, and water resistance. Etc., it is widely used as an insulator and sheath material for electric wires and cables.

  On the other hand, in recent years, as awareness of global environmental protection has increased, there has been an increasing movement to regulate the use of materials with a large environmental load, and the above-mentioned PVC is also harmful due to halogens in the event of a fire or incineration. The use of halogen gas and dioxin is being limited due to the generation of halogen gas and dioxin.

  For this reason, a highly environmentally friendly flame retardant material for covering wires and cables that replaces PVC, that is, a non-halogen flame retardant material that does not contain halogen and does not generate harmful substances such as halogen gas or dioxin during combustion. There is a strong demand.

  As such non-halogen flame retardant materials for covering electric wires and cables, flame retardant ethylene polymers, for example, flame retardant by adding a large amount of metal hydroxide such as magnesium hydroxide or aluminum hydroxide to polyethylene Is known (for example, see Patent Document 1).

However, in this composition, due to the addition of a large amount of metal hydroxide, the original excellent properties of the ethylene-based polymer, especially mechanical properties (for example, tensile strength, elongation, etc.) are impaired. There is a problem that the cable cannot have sufficient required characteristics.
JP 2000-11765 A

  As described above, there is a demand for a non-halogen non-halogen wire / cable flame retardant material that replaces PVC, but metals such as magnesium hydroxide and aluminum hydroxide have been added to conventional flammable ethylene polymers. The flame retardant added with a hydroxide has a problem that the mechanical properties are particularly deteriorated.

  The present invention has been made in order to solve such problems of the prior art, and is a non-halogen flame retardant composition that does not generate harmful gases such as halogen gas and dioxin during combustion, and is excellent. Providing flame retardant compositions for wire and cable coatings that have flame retardancy and good mechanical properties such as tensile strength, and flame retardant wires and cables using such flame retardant compositions The purpose is to do.

  As a result of intensive studies to achieve the above object, the present inventors have used non-halogen having both good flame retardancy and mechanical properties by using nanoclay as a flame retardant aid in combination with metal hydroxides. The inventors have found that a flame retardant composition can be obtained, and have completed the present invention.

  That is, the first invention of the present application is a non-halogen flame retardant composition mainly composed of an ethylene-based polymer, and (a) 30 to 100 parts by weight of a metal hydroxide per 100 parts by weight of the ethylene-based polymer, (B) A flame retardant composition for covering electric wires and cables, which contains 1 to 10 parts by weight of nanoclay.

  In the flame retardant composition for covering an electric wire / cable, the composition contains (a) 50 to 80 parts by weight of metal hydroxide and (b) 3 to 8 parts by weight of nanoclay per 100 parts by weight of the ethylene polymer. There may be.

  In the flame retardant composition for covering an electric wire / cable, the ethylene-based polymer may contain an ethylene / vinyl acetate copolymer.

  In the flame retardant composition for covering an electric wire / cable, the metal hydroxide may contain aluminum hydroxide.

  In the flame retardant composition for covering an electric wire / cable, the nanoclay (b) may have a thickness of 10 nm or less and an aspect ratio of 100 to 500. The layered clay particles may be distearyldimethylammonium. It may be obtained by treatment with chloride. Here, the aspect ratio refers to the ratio of the maximum length to the maximum thickness of the particles.

  Moreover, 2nd invention of this application is a flame-retardant electric wire and cable characterized by having the coating | cover consisting of the said flame-retardant composition for electric wire and cable coating | cover.

  The flame retardant composition for covering electric wires and cables of the present invention is non-halogen, has excellent flame retardancy comparable to conventional flame retardant materials based on PVC, and also has good mechanical properties. is there.

  Moreover, since the flame-retardant electric wire / cable of this invention has the coating | cover which has such a characteristic, it can have high reliability as a flame-retardant electric wire / cable with high environmental conservation.

Hereinafter, the present invention will be described in detail.
Examples of the ethylene polymer used in the flame retardant composition for covering electric wires and cables of the present invention include low density polyethylene (LDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), and very low density polyethylene (VLDPE). ), Polyethylene such as linear low density polyethylene (LLDPE), polypropylene (PP), ethylene / ethyl acrylate copolymer (EEA), ethylene / methyl acrylate copolymer (EMA), ethylene / ethyl methacrylate copolymer Examples thereof include a polymer, an ethylene / vinyl acetate copolymer (EVA), an ethylene / propylene copolymer (EP), an ethylene / propylene / diene copolymer (EPDM), and polyisobutylene. Moreover, what copolymerized alpha-olefin, cyclic olefins, etc., such as propylene, butene, pentene, hexene, and octene, can be used for the metallocene catalyst. These are used alone or in combination. In the present invention, an ethylene / vinyl acetate copolymer is preferable, and the other ethylene-based polymer is preferably used as a combined component of the ethylene / vinyl acetate copolymer. In this case, the ethylene-based polymer other than the ethylene / vinyl acetate copolymer is preferably 50% by weight or less of the entire ethylene-based polymer, and if it exceeds 50% by weight, the mechanical properties are deteriorated.

  In addition, examples of the (a) metal hydroxide used in the flame retardant composition for covering electric wires and cables of the present invention include magnesium hydroxide, aluminum hydroxide, basic magnesium carbonate, hydrotalcite and the like. . These can be used alone or in combination.

  The compounding amount of the metal hydroxide (a) is in the range of 30 to 100 parts by weight, preferably 50 to 80 parts by weight, with respect to 100 parts by weight of the above-mentioned ethylene polymer. If the blending amount is less than 30 parts by weight, sufficient flame retardancy cannot be obtained, and conversely if it exceeds 100 parts by weight, the mechanical properties are deteriorated.

  Furthermore, the (b) nanoclay used in the flame retardant composition for covering electric wires and cables of the present invention is a layered layer of montmorillonite, bentonite or hectorite mainly composed of montmorillonite, that is, a scaly shape having a high aspect ratio. Nano-sized plate-like particles obtained by treating inorganic minerals with organic materials. In order to obtain the effects of the present invention, those having a particle diameter (XY dimension) of 1000 nm or less, a thickness (dimension in the Z direction) of 10 nm or less, and an aspect ratio of 100 to 500 are preferably used. The particle diameter (XY dimension) is more preferably 100 to 500 nm, and the thickness (dimension in the Z direction) is more preferably 3 nm or less. In addition, one obtained by treating layered clay particles with distearyldimethylammonium chloride, that is, a nanoclay whose surface is modified with distearyldimethylammonium chloride is one of those preferably used as (b) nanoclay in the present invention. However, when an ethylene / vinyl acetate copolymer is used as the ethylene polymer component, the effect of improving flame retardancy is great, which is particularly preferable.

  The nanoclay of (b) acts as a flame retardant aid for the metal hydroxide of (a), reduces the amount used, and prevents the mechanical properties from deteriorating due to the blending of the metal hydroxide of (a). Has the effect of The amount of nanoclay (b) is 1 to 10 parts by weight, preferably 3 to 8 parts by weight, based on 100 parts by weight of the above-described ethylene-based polymer. If the blending amount is less than 1 part by weight, the effect due to addition cannot be obtained. Conversely, if the blending amount exceeds 10 parts by weight, the mechanical strength decreases.

  In addition, the nano clay of (b) has the effect which provides the dripping prevention property at the time of the combustion which was excellent in the composition with the said effect. However, although this effect is remarkable when aluminum hydroxide is used for the metal hydroxide of (a), it is hardly recognized when magnesium hydroxide is used. In order to obtain the properties, it is preferable to use aluminum hydroxide for the metal hydroxide of (a).

  The flame retardant composition for covering electric wires and cables of the present invention includes, in addition to the above components, a plasticizer, a softener, an antioxidant, and an ultraviolet absorber as long as they do not impair the effects of the present invention. Additives such as an agent, a heat aging inhibitor, a filler, a processing aid, a crosslinking agent, a crosslinking aid, a lubricant, a colorant, and a stabilizer can be blended. For example, examples of the plasticizer include fatty acids such as stearic acid and oleic acid, and metal salts thereof. Examples of the softener include mineral oil, wax, paraffins and the like. Furthermore, non-halogen flame retardants and flame retardant aids other than the metal hydroxides and nano clays described above can also be blended within a range that does not impair the effects of the present invention. Examples of such non-halogen flame retardants and flame retardant aids include guanidine and melamine nitrogen flame retardants, phosphorus phosphate flame retardants such as ammonium phosphate and red phosphorus, phosphorus-nitrogen flame retardants, and zinc borate. Examples thereof include boric acid compounds such as calcium carbonate, and silicone flame retardant aids.

  The flame retardant composition for covering an electric wire / cable of the present invention is obtained by uniformly mixing the above components using a conventional kneader such as a Banbury mixer, a tumbler, a pressure kneader, a kneading extruder, or a mixing roller. It can be manufactured easily.

  In addition, the flame retardant composition for covering an electric wire / cable of the present invention obtained as described above may be extrusion-coated on the outer periphery of a conductor directly or through another coating, or wound in a tape shape. Thus, the flame-retardant electric wire / cable of the present invention is manufactured. The composition is crosslinked by a conventional method after coating or molding, if necessary.

FIG. 1 shows an example of a flame retardant cable according to the present invention.
As shown in FIG. 1, this cable is formed by twisting a plurality of insulated wire cores 3 (three in the example of the drawing) in which an insulating layer 2 such as polyethylene or crosslinked polyethylene is coated on a conductor 1 made of copper or aluminum. Thus, the cable core 4 is formed and a flame retardant sheath 5 is provided on the cable core 4. The flame retardant sheath 5 is formed by extruding the flame retardant composition for covering an electric wire / cable described above.

  In such a flame retardant cable, the flame retardant sheath 5 is formed of a non-halogen flame retardant composition for covering electric wires and cables having both excellent flame retardancy and good mechanical properties. High reliability as a fuel cable.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples at all.

Example 1
100 parts by weight of ethylene / vinyl acetate copolymer (EVA; trade name EV180 manufactured by Mitsui DuPont Polychemical Co., Ltd.), 30 parts by weight of aluminum hydroxide (trade name Heidilite H-42 manufactured by Showa Denko KK), and nanoclay (Zud Chemie) A resin composition was obtained by uniformly kneading 5 parts by weight of a product name “Nanofil SE3000” manufactured by a company using a pressure kneader.

  Next, while twisting four insulated wire cores having a 0.4 mm thick polyethylene insulation layer on a 0.8 mmφ copper conductor, the resin composition is extrusion coated on the outer periphery to form a sheath of about 1 mm thickness Thus, a cable having an outer diameter of about 6.5 mm was manufactured.

Examples 2-5, Comparative Examples 1-4
A resin composition was obtained in the same manner as in Example 1 except that the blending components and blending amounts were changed as shown in Table 1, and a cable was obtained in the same manner as in Example 1 by using the obtained resin composition. Manufactured. In addition, the magnesium hydroxide used in Examples 4 and 5 is Kisuma 5A (trade name) manufactured by Kyowa Chemical Industry Co., Ltd.

About the resin composition obtained by each said Example and each comparative example, various characteristics were evaluated by the method shown below.
[Tensile strength and elongation]
The flame retardant composition was heat-press molded under conditions of 180 ° C. × 5 minutes and a pressure of 20 MPa with a press machine to prepare a test sheet, and tensile strength and elongation were measured according to JIS K 6251.
[Oxygen index]
A test sheet was prepared in the same manner as described above, and the oxygen index was measured according to JIS K7201.
[Drip prevention during combustion]
Make a test piece of 6.5mm x 150mm x 1mm in the same way as above, hold it vertically and lay absorbent cotton underneath it, and indirect flame with a tyryl burner (flame height 19mm) for 5 seconds. Examined. Evaluation was performed by the presence or absence of generation | occurrence | production of the harmful molten dripping which ignites the absorbent cotton from a test piece.
These results are shown in the lower column of Table 1.

  As is clear from Table 1, the resin compositions of the examples to which nanoclay was added showed improvement in mechanical properties as compared with the comparative examples to which no nanoclay was added, and in particular, examples in which nanoclay and aluminum hydroxide were used in combination. In 1-3, it had the dripping prevention property at the time of combustion more favorable.

It is a cross-sectional view which shows an example of the flame-retardant cable of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Conductor, 2 ... Insulating layer, 3 ... Insulated wire core, 4 ... Cable core, 5 ... Flame-retardant sheath

Claims (7)

A non-halogen flame retardant composition mainly composed of an ethylene polymer,
A flame retardant composition for covering electric wires and cables, comprising (a) 30 to 100 parts by weight of a metal hydroxide and (b) 1 to 10 parts by weight of nanoclay per 100 parts by weight of an ethylene-based polymer. .   The wire / cable coating according to claim 1, comprising (a) 50 to 80 parts by weight of a metal hydroxide and (b) 3 to 8 parts by weight of nanoclay per 100 parts by weight of the ethylene-based polymer. Flame retardant composition.   The flame retardant composition for covering an electric wire / cable according to claim 1 or 2, wherein the ethylene-based polymer contains an ethylene / vinyl acetate copolymer.   The flame retardant composition for covering electric wires and cables according to any one of claims 1 to 3, wherein the metal hydroxide contains aluminum hydroxide.   The flame retardant composition for covering electric wires and cables according to any one of claims 1 to 4, wherein the nanoclay (b) has a thickness of 10 nm or less and an aspect ratio of 100 to 500.   6. The flame retardant composition for covering electric wires and cables according to claim 1, wherein the nanoclay (b) is obtained by treating layered clay particles with distearyldimethylammonium chloride.   A flame-retardant electric wire / cable having a coating made of the flame-retardant composition for coating an electric wire / cable according to any one of claims 1 to 6.

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