JP2011256325A - Frame-retardant composition for covering electric wire and cable, and electric wire and cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress generation of quality uniformity decrease and defective appearance of electric wires and cables, caused by aluminum hydroxide of a halogen-free frame-retardant composition for covering electric wire and cable, using aluminum hydroxide as a frame-retardant.SOLUTION: The frame-retardant composition for covering electric wire and cable is a non-halogen flame-retardant composition and includes (C) 40-120 pts.mass aluminum hydroxide and 100 pts.mass base polymer comprising (A) 80-95 mass% polyolefin and (B) 5-20 mass% sodium polyacrylate crosslinked product. The electric wires and cables have coating comprising such composition.

Description

  TECHNICAL FIELD The present invention relates to a flame retardant composition for covering an electric wire / cable that is halogen-free and has high flame retardancy, and an electric wire / cable using the same.

  In recent years, in the electric wire / cable field, in order to reduce the burden on the environment, instead of a composition containing polyvinyl chloride (PVC) or a halogen-based flame retardant that generates harmful gases such as hydrogen halide during incineration. Coated with a so-called halogen-free flame retardant composition in which a polymer containing no halogen such as polyolefin is used as a base polymer component and a large amount of metal hydroxide such as aluminum hydroxide or magnesium hydroxide is added as a flame retardant. Electric wires and cables used as materials have come to be used (for example, see Patent Document 1).

  In such a halogen-free flame retardant composition for covering an electric wire or cable, aluminum hydroxide or magnesium hydroxide is generally used as a flame retardant as described above. It is used a lot. This is because aluminum hydroxide and magnesium hydroxide have a high effect of imparting flame retardancy, and are inexpensive and easily available. Among them, magnesium hydroxide is frequently used. This is because the dehydration decomposition temperature of aluminum is around 200 ° C., whereas magnesium hydroxide is as high as around 330 ° C. In other words, when aluminum hydroxide is used, dehydration and decomposition occur during the production of electric wires and cables, and the generated moisture precipitates and foams on the coating, which may impair quality uniformity and appearance. This is because magnesium hydroxide has a high decomposition temperature, and there is no possibility that these problems will occur.

  However, there is still a need for aluminum hydroxide from the viewpoints of the combined use with magnesium hydroxide and the like in terms of electrical and mechanical properties of electric wires and cables and flame retardancy. For this reason, halogen-free flame retardant compositions that do not impair quality uniformity and appearance even when aluminum hydroxide is used as a flame retardant, and electric wires and cables using such compositions. It is requested.

Japanese Patent Application Laid-Open No. 2000-239459

  The present invention has been made to solve such problems of the prior art, and is a halogen-free flame retardant composition using aluminum hydroxide as a flame retardant, having excellent flame retardancy, An object of the present invention is to provide a flame retardant composition for covering electric wires and cables that does not impair the uniformity and appearance of cable quality, and an electric wire and cable using such a flame retardant composition.

  As a result of intensive studies to achieve the above-mentioned object, the present inventors have good flame retardancy by blending a sodium polyacrylate cross-linked product known as a water-absorbent resin at a specific ratio, and The present inventors have found that a halogen-free flame-retardant composition that does not impair the uniformity of the quality and appearance of the electric wire / cable and an electric wire / cable using the halogen-free flame retardant composition have been obtained.

  That is, the flame retardant composition for covering electric wires and cables according to the first aspect of the present invention is a non-halogen flame retardant composition, and comprises (A) 80 to 95% by mass of polyolefin and (B) sodium polyacrylate crosslinked. It is characterized by containing (C) 40 to 120 parts by mass of aluminum hydroxide with respect to 100 parts by mass of the base polymer comprising 5 to 20% by mass of the body.

  The flame retardant composition for electric wire / cable coating of the second aspect of the present invention is the flame retardant composition for electric wire / cable coating of the first aspect, wherein the component (C) is added to 100 parts by mass of the base polymer. The content of aluminum hydroxide is 50 to 80 parts by mass.

  The flame retardant composition for electric wire / cable coating of the third aspect of the present invention is the flame retardant composition for electric wire / cable coating of the first or second aspect, wherein the component (B) in the base polymer The content of the cross-linked sodium polyacrylate is 5 to 15% by mass.

  The flame retardant composition for electric wire / cable coating according to the fourth aspect of the present invention is the flame retardant composition for electric wire / cable coating according to any one of the first to third aspects. B) Content of sodium polyacrylate as a component is 8 to 12% by mass.

  The flame retardant composition for covering an electric wire / cable according to the fifth aspect of the present invention is the flame retardant composition for covering an electric wire / cable according to any one of the first to fourth aspects. The cross-linked sodium polyacrylate is characterized by comprising particles having a particle size of 110 μm or less.

  The flame retardant composition for electric wire / cable coating according to the sixth aspect of the present invention is the flame retardant composition for electric wire / cable coating according to the fifth aspect, wherein the cross-linked sodium polyacrylate of component (B) is used. Is composed of particles having an average particle diameter of 20 to 30 μm.

  The electric wire / cable according to the seventh aspect of the present invention is characterized by having a coating made of any one of the first to sixth electric wire / cable coating flame retardant compositions.

  According to the present invention, a halogen-free flame retardant composition in which aluminum hydroxide is used as a flame retardant, has excellent flame retardancy and impairs the uniformity and appearance of the quality of electric wires and cables. There are provided a flame retardant composition for covering electric wires and cables, and an electric wire and cable using such a flame retardant composition.

It is sectional drawing which shows an example of the electric wire and cable of this invention.

  Embodiments of the present invention will be described below.

  First, the flame retardant composition for covering electric wires and cables of the present invention will be described.

  Examples of the component (A) polyolefin used as the base polymer of the flame retardant composition for covering electric wires and cables of the present invention include, for example, low density polyethylene (LDPE), medium density polyethylene (MDPE), and high density polyethylene (HDPE). ), Polyethylene such as very low density polyethylene (VLDPE), linear low density polyethylene (LLDPE); polypropylene (PP); polyisobutylene; ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1- Heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-nonadecene, 1-eicosene, Copolymerization of α-olefins such as 4-methyl-1-pentene Ethylene / α-olefin copolymer; ethylene, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl persate, vinyl laurate, vinyl stearate, vinyl benzoate, vinyl salicylate, vinyl cyclohexanecarboxylate, etc. Ethylene / vinyl ester copolymer obtained by copolymerization of vinyl ester; ethylene, methyl acrylate, ethyl acrylate, isopropyl acrylate, isobutyl acrylate, n-butyl acrylate, isooctyl acrylate, 2-ethylhexyl acrylate , Ethylene / acrylic acid ester copolymer obtained by copolymerizing unsaturated carboxylic acid ester such as methyl methacrylate, ethyl methacrylate, isobutyl acrylate, dimethyl maleate, diethyl maleate, etc .; isobutylene / isoprene Such as polymers and the like. As the polypropylene, not only a homopolymer of propylene, but also a random copolymer or block copolymer with ethylene, a copolymer with a small amount of α-olefin, and the like can be used. Examples of the α-olefin include 1-butene, 1-pentene, 1-hexene, 1-octene, 4-methyl-1-pentene and the like. A non-conjugated polyene may be further copolymerized with the propylene / α-olefin copolymer. Examples of the non-conjugated polyene include dicyclopentadiene, 1,4-hexadiene, ethylidene norbornene, and vinyl norbornene. These may be used individually by 1 type and may be used in combination of 2 or more type.

  It is generally used as a cable coating material and is easy to recycle. As the polyolefin (A), low density polyethylene (LDPE), polypropylene (PP), ethylene / vinyl acetate copolymer (EVA), ethylene -Ethyl acrylate copolymer (EEA) is preferable. Moreover, you may blend each polymer.

Moreover, the sodium polyacrylate crosslinked body of the component (B) used as the base polymer of the flame retardant composition for covering electric wires and cables of the present invention is known as a water absorbent resin. In this invention, it is preferable to use what consists of particle | grains with a particle size of 110 micrometers or less as a sodium polyacrylate crosslinked body of (B) component. By using particles composed of particles having a particle size of 110 μm or less, the mixing workability with the polyolefin (A) and other components can be improved and dispersed uniformly in the composition. Moreover, from the viewpoint of the mechanical strength of the composition, it is more preferable that the particle diameter is 110 μm or less and the average particle diameter (D ₅₀ ) is in the range of 20 to 30 μm. In addition, the particle diameter and average particle diameter of a sodium polyacrylate crosslinked body can be calculated | required by the sieving method. An example of a commercially available sodium polyacrylate crosslinked product having a particle size of 110 μm or less and an average particle size in the range of 20 to 30 μm is, for example, Aqua Keep 10SH-NF (manufactured by Sumitomo Seika Co., Ltd. Product name).

  The blend ratio of the component (A) and the component (B) in the base polymer of the flame retardant composition for covering electric wires and cables of the present invention is such that the polyolefin of the component (A) is 80 to 95% by mass, preferably 85 to 95. It is 5 to 20% by mass, preferably 5 to 15% by mass, more preferably 8 to 12% by mass, more preferably 88 to 92% by mass, and (B) component sodium polyacrylate crosslinked body. When the blending ratio of the component (A) polyolefin is less than 80% by mass, the mechanical strength decreases. When the blending ratio of the component (A) polyolefin exceeds 95% by mass, the (B) component polyacrylic acid The ratio of the sodium cross-linked body becomes small, and it becomes impossible to suppress the deterioration of the homogeneity of the quality of the electric wire / cable and the appearance defect caused by the dehydration decomposition reaction of aluminum hydroxide during the production of the electric wire / cable.

  The aluminum hydroxide of component (C) used in the flame retardant composition for covering electric wires and cables of the present invention releases water when exposed to high temperatures, and suppresses the temperature rise by heat of vaporization at that time. It exhibits a flame retardant effect. Aluminum hydroxide may be surface-treated with a higher fatty acid such as stearic acid or oleic acid or a metal salt thereof, or a silane coupling agent, and is not surface-treated with the surface-treated one. It may be a mixture of things. By using surface-treated aluminum hydroxide, the dispersibility when kneading with the base polymer can be enhanced. Moreover, the average particle diameter of aluminum hydroxide is preferably 30 μm or less, and more preferably 5 μm or less. When the average particle diameter exceeds 30 μm, the composition may not be uniformly dispersed in the base polymer and a composition having sufficient flame retardancy may not be obtained. The average particle diameter of aluminum hydroxide can be measured using a laser diffraction / scattering particle size distribution analyzer.

  The compounding amount of the aluminum hydroxide as the component (C) is 40 to 120 parts by mass, preferably 50 to 80 with respect to 100 parts by mass of the total amount of the component (A) and the component (B) as the base polymer component. Part by mass. If the blending amount is less than 40 parts by mass, sufficient flame retardancy cannot be obtained, and conversely if it exceeds 120 parts by mass, the mechanical strength decreases.

  In addition to the above components, the flame retardant composition for covering electric wires and cables of the present invention, if necessary, within a range not impairing the effects of the present invention, plasticizers, softeners, antioxidants, light stable Agents, heat aging inhibitors, fillers, processing aids, crosslinking agents, crosslinking aids, lubricants, colorants, stabilizers and other additives 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 softening agent include mineral oil, wax, paraffins and the like. Examples of the filler include fused silica, crystalline silica, alumina, zirconia, talc, clay, mica, calcium carbonate, titanium white, bengara, silicon carbide, boron nitride, silicon nitride, and aluminum nitride. Examples of processing aids include ricinoleic acid, stearic acid, palmitic acid, lauric acid, and salts or esters thereof. Examples of the lubricant include hydrocarbons, fatty acids, fatty acid amides, esters, and alcohols.

  Furthermore, other non-halogen flame retardants other than the above-described aluminum hydroxide can also be blended within a range that does not impair the effects of the present invention. Such non-halogen flame retardants include metal hydroxides such as magnesium hydroxide and calcium hydroxide, nitrogen flame retardants such as guanidine and melamine, and phosphorus flame retardants such as ammonium phosphate and red phosphorus. Examples thereof include phosphorus-nitrogen flame retardants, boric acid compounds such as zinc borate, calcium carbonate, and the like.

  In addition, a water-absorbing resin other than the above-mentioned crosslinked poly (sodium acrylate) can also be blended within a range that does not impair the effects of the present invention. Examples of such a water-absorbing resin include starch-based, cellulose-based, polyvinyl alcohol-based, and polyoxyethylene-based resins. Polyacrylic acid-based water-absorbing resins other than the sodium polyacrylate cross-linked product can also be used.

  The flame retardant composition for covering an electric wire / cable of the present invention comprises the above-described components (A) to (C) and the above-described various components that are blended as necessary. It can be easily produced by uniform mixing using a conventional kneader such as a kneader, a kneading extruder, or a mixing roller.

  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 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 is a cross-sectional view showing an embodiment of the electric wire / cable of the present invention.

In FIG. 1, 1 shows a copper stranded wire conductor having a cross-sectional area of 2 mm ² , for example. On the copper stranded wire conductor 1, the above-described flame retardant composition for covering electric wires and cables is extrusion coated. For example, an insulator 2 having a thickness of 0.9 mm is formed.

  The insulated electric wire configured as described above can be provided with an insulating material that has excellent halogen-free flame retardancy and is homogeneous and has a good appearance.

  The present invention is not limited to the embodiment described above, and it is needless to say that the present invention can be implemented in various forms without departing from the gist of the present invention.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples at all. In addition, the component used by the Example and the comparative example is as follows.

Ethylene / ethyl acrylate copolymer:
Product name manufactured by Nippon Polyethylene Co., Ltd. Lexpearl EEA A1150
(EA content 15%)
Ethylene / vinyl acetate copolymer:
Product name Evaflex V5274 manufactured by Mitsui DuPont Polychemical Co., Ltd.
(VA content 17%)
Low density polyethylene:
Nippon Unicar Co., Ltd. Product name DFDJ-7540
Cross-linked sodium polyacrylate:
Product name Aqua Keep 10SH-NF, manufactured by Sumitomo Seika Co., Ltd.
(Particle diameter 106 μm or less, average particle diameter (D ₅₀ ) 20-30 μm)
Aluminum hydroxide:
Product name Heidilite H42STV manufactured by Showa Denko K.K.
(Average particle size 1.0μm)

Example 1
80 parts by mass of an ethylene / ethyl acrylate copolymer, 20 parts by mass of a crosslinked sodium polyacrylate, and 85 parts by mass of aluminum hydroxide were uniformly kneaded using a pressure kneader to obtain a flame retardant composition.

Subsequently, the flame retardant composition was extrusion coated to a thickness of 0.9 mm on a copper stranded wire conductor having a cross-sectional area of 2 mm ² (extrusion temperature 200 ° C.) to produce an insulated wire having an outer diameter of about 3.4 mm.

Examples 2-24, Comparative Examples 1-18
A flame retardant composition was obtained in the same manner as in Example 1, except that the blending components and / or blending amounts were changed as shown in Tables 1 to 3, and the obtained flame retardant composition was used. An insulated wire was manufactured in the same manner as in Example 1.

About the insulated wire obtained by each said Example and each comparative example, various characteristics were evaluated by the method shown below.
[appearance]
The surface of the insulated wire was visually observed and evaluated according to the following criteria.
A: Very good (no surface foaming)
○: Good (no surface foaming)
X: Defect (with surface foaming)
[amount of water]
Immediately after extruding the flame retardant composition, the amount of water adhering to the surface of the insulated wire was measured by the Karl Fischer method (150 ° C.).
[Tensile strength / elongation]
A tubular test piece having a length of 150 mm produced by pulling out an internal conductor from a flame-retardant electric wire was measured in accordance with JIS C 3005 under conditions of a marked line of 50 mm and a tensile speed of 200 mm / min.
[Flame retardance]
A 60-degree inclined combustion test defined in JIS C 3005 was conducted on an electric wire sample having a length of about 300 mm cut out from an insulated electric wire, and pass / fail was determined.

  These results are shown in the lower column of Tables 1 to 3.

  As is apparent from Tables 1 to 3, in Examples 1, 9 and 17, good evaluation results were obtained in both appearance and mechanical properties. Moreover, in Examples 2-8, 10-16, and 18-24, the external appearance was favorable and the further favorable evaluation result of the mechanical characteristic was obtained. In particular, in Examples 4, 5, 12, 13, 20, and 21, both the appearance and the mechanical properties were extremely good.

  DESCRIPTION OF SYMBOLS 1 ... Copper twisted wire conductor, 2 ... Coating | cover.

Claims (7)

  Non-halogen flame retardant composition comprising (A) 80 to 95% by mass of polyolefin and (B) 100 parts by mass of a base polymer consisting of 5 to 20% by mass of a sodium polyacrylate crosslinked product, and (C) aluminum hydroxide 40 to 120 parts by mass of a flame retardant composition for covering electric wires and cables.   2. The flame retardant composition for covering electric wires and cables according to claim 1, wherein the content of the aluminum hydroxide of component (C) is 50 to 80 parts by mass with respect to 100 parts by mass of the base polymer.   The flame retardant composition for covering electric wires and cables according to claim 1 or 2, wherein the content of the cross-linked sodium polyacrylate as the component (B) in the base polymer is 5 to 15% by mass.   The flame retardant composition for covering electric wires and cables according to claim 1, wherein the content of the cross-linked sodium polyacrylate as the component (B) in the base polymer is 8 to 12% by mass.   The flame retardant composition for covering electric wires and cables according to any one of claims 1 to 4, wherein the crosslinked sodium polyacrylate as the component (B) comprises particles having a particle size of 110 µm or less. .   6. The flame retardant composition for covering electric wires and cables according to claim 5, wherein the crosslinked sodium polyacrylate as the component (B) comprises particles having an average particle diameter of 20 to 30 [mu] m.   An electric wire / cable having a coating made of the flame retardant composition for covering an electric wire / cable according to any one of claims 1 to 6.

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