JP2000327858A - Flame-retardant resin composition, and electric wire and cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-halogen, flame-retardant resin composition which imparts sufficient mechanical strength and excellent flame-retardancy without causing working strain after molding and to provide an electric wire and cable having an insulator or a jacket composed of a non-halogen, flame-retardant resin which does not shrink to the extent of exposing the inside on burning. SOLUTION: The title non-halogen, flame-retardant resin composition comprises 100 pts.wt. of an ethylene polymer having a weight average mol.wt. to number average mol.wt. ratio of not more than 3.8, 0.2-3 pts.wt. of a fatty acid or a derivative thereof and 30-200 pts.wt. of a metal hydroxide flame- retardant. This composition is employed for preparing an insulator 5 or a jacket 7 of an electric wire and cable.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flame-retardant resin composition and an electric wire / cable, and more particularly, to a flame-retardant resin composition containing no halogen compound, and an insulated wire / insulating material using the same. About the cable.

[0002]

2. Description of the Related Art As a non-halogen flame-retardant resin composition used as an insulator or a sheath of an electric wire or a cable, an ethylene polymer to which a metal hydroxide has been added as a flame retardant has been generally used. . As the ethylene-based polymer, a polymer having a melt index of 1.0 or less and a high molecular weight is used from the viewpoint of material strength, and ethylene-ethyl acrylate is used from the viewpoint of flame retardancy and filling properties of the flame retardant. Polymer (EEA) and ethylene / vinyl acetate copolymer (EVA) are mainly used.

[0003]

However, in order to obtain material strength, a non-halogen flame-retardant resin composition using a polymer having a melt index of 1.0 or less has the following problems. (1) Poor liquidity. (2) Processing distortion tends to remain after molding. (3) The load applied to the processing machine is large. If the processing distortion remains, the molded product becomes sensitive to thermal and mechanical stress. In particular, when used for wire jackets, the jacket shrinks in the event of burning, exposing the inner insulator,
This may result in faster fire spread.

On the other hand, a non-halogen flame-retardant resin composition using a low-molecular-weight polymer having a melt index of more than 1.0 does not have these problems, but has sufficient strength of a processed product such as an insulator. Absent.

It is an object of the present invention to provide a non-halogen flame-retardant resin composition which has no processing distortion after molding, provides sufficient mechanical strength and excellent flame retardancy.

Another object of the present invention is to provide an electric wire having a jacket made of a non-halogen flame-retardant resin, which is not sensitive to thermal and mechanical stress, has sufficient mechanical strength and excellent flame retardancy.・ To provide cables.

Still another object of the present invention is to provide an electric wire or cable having a jacket made of a non-halogen flame-retardant resin, which does not cause shrinkage such that the inside is exposed even in the event of burning. is there.

[0008]

To achieve the above object, the present invention provides a flame-retardant resin composition comprising a halogen-free component, wherein the ratio of 100 parts by weight of the weight-average molecular weight to the number-average molecular weight is 3. A flame-retardant resin composition comprising an ethylene polymer of 8 or less, 0.2 to 3 parts by weight of a fatty acid or a derivative thereof, and 30 to 200 parts by weight of a metal hydroxide flame retardant.

According to another aspect of the present invention, there is provided an electric wire or cable in which an insulated wire in which a conductor is covered with an insulator is covered with a jacket. An ethylene polymer having a ratio of the weight average molecular weight to the number average molecular weight of 3.8 or less,
0.2 to 3 parts by weight of a fatty acid or a derivative thereof;
An electric wire / cable formed of a flame-retardant resin composition comprising from 1 to 200 parts by weight of a metal hydroxide flame retardant.

In the present invention, the ratio (Mw) of the weight average molecular weight (Mw) of the ethylene polymer to the number average molecular weight (Mn) is determined.
/ Mn) is used as a scale for evaluating the molecular weight distribution of the polymer. The smaller this ratio, the smaller the molecular weight distribution of the polymer. The weight average molecular weight (Mw) and number average molecular weight (Mn) of the ethylene polymer are based on those measured by high-temperature gel permeation chromatography (GPC). At the time of measurement, orthodichlorobenzene was used as a solvent,
From the molecular weight (weight average molecular weight Mw and number average molecular weight Mn) measured at a flow rate of 1 milliliter per minute at ° C, the ratio Mw /
Mn was calculated. As the GPC column, for example, three GMHHR (S) manufactured by Tosoh Corporation are used.

[0011] The ethylene polymer includes not only a homopolymer of ethylene but also a copolymer. For example, low density polyethylene, linear low density polyethylene, polyethylene such as linear ultra low density polyethylene, ethylene and methyl acrylate, methyl methacrylate, ethyl acrylate, vinyl acetate, glycidyl methacrylate, butene-
1, copolymers with propylene, ethylene-butene-hexene terpolymer, ethylene-propylene-butadiene terpolymer, poly-4-methylpentene-1, and maleic acid-grafted low-density polyethylene. These can be used alone and blended, and may be rubber.

In order to prevent residual distortion during processing and to secure mechanical strength, an ethylene polymer having a melt index of 1.0 to 10 is preferred. If the melt index is less than 1.0, the residual strain during processing is large, and
If it exceeds 0, the kneading processability and the strength of the formed insulating layer and the like are inferior.

Having a melt index in the range of 1.0 to 10 and a vinyl acetate content of 10 to 50 mol%
When the ethylene-vinyl acetate copolymer (EVA) is used, a flame-retardant resin composition having good flexibility, flexibility, flame retardancy, and kneading properties can be obtained, and flexibility, flexibility, and flame retardancy can be obtained. A non-halogen flame-retardant insulated wire with good performance can be obtained. If the vinyl acetate content is less than 10%, the flexibility, flexibility and flame retardancy are poor.
If it exceeds 0%, the tackiness at the time of melting becomes large, and kneading becomes difficult.

When the base polymer of the non-halogen flame-retardant resin composition is a mixture containing 97 to 60% by weight of such an EVA and 3 to 40% by weight of an acid-modified polyolefin having a melt index of 10 or less, heating is performed. Deformation due to is particularly small. 4 acid-modified polyolefins
If it exceeds 0% by weight, the tackiness becomes strong and kneading becomes difficult.

The acid-modified polyolefin includes ethylene-maleic anhydride copolymer, maleic acid-grafted linear low density polyethylene, methyl acrylate, methyl methacrylate, ethyl acrylate, ethylene acrylate,
Vinyl acetate copolymer, ethylene-ethyl acrylate-
Maleic anhydride terpolymers are included.

97 to 60% by weight of the base polymer
A non-halogen flame-retardant resin composition which is a mixture of EVA of 3 to 40% by weight and an acid-modified polyolefin having a melt index of 10 or less, wherein the acid-modified polyolefin is ethylene-ethyl acrylate-maleic anhydride ternary. When a copolymer is used, flame retardancy is particularly excellent. This is ethylene-ethyl acrylate (EE
In addition to the shell-forming properties of A) (the property of forming a shell during combustion and preventing fire spread), the maleic anhydride functional group adheres tightly to the surface of the metal hydroxide to reinforce the hardening of the entire system. It is presumed that the effect is large.

In the resin composition of the present invention, the fatty acid derivative includes soap, metal soap, fatty acid amide, fatty acid ester (glyceride and the like). Fatty acids may be either saturated or unsaturated. Among these, sodium stearate (soap) and metal soaps such as zinc stearate, lithium hydroxystearate, lithium stearate, calcium hydroxystearate and magnesium hydroxystearate are preferred because of their high external activity.

If the fatty acid or its derivative exceeds 3 parts by weight, the mechanical strength of a processed product such as an insulating layer decreases.

The non-halogen flame-retardant resin composition of the present invention may contain one or more flame retardants composed of a metal hydroxide or the like in order to improve the flame retardancy. 3
0 to 200 parts by weight is preferred. As the flame retardant, a metal oxide, phosphorus or a phosphorus compound can be used in addition to the metal hydroxide.

The metal hydroxide used as a flame retardant is, for example, magnesium hydroxide, aluminum hydroxide, hydrotalcite, calcium aluminate hydrate, calcium hydroxide, barium hydroxide, or hard clay. Particularly, magnesium hydroxide having a small number of coarse particles and an average particle diameter of 8 μm or less is preferable in view of flame retardancy and appearance of a processed molded product. When coarse particles are included, irregularities appear on the surface of the drawn-down tube extruded product in extrusion molding.

The metal oxide used as the flame retardant is, for example, antimony oxide, aluminum oxide or magnesium oxide. Phosphorus compounds include phosphates, phosphonates, and phosphorinene. Addition of red phosphorus has a large effect of improving flame retardancy.

A compounding agent such as a flame retardant may be surface-treated with a fatty acid metal salt, a silane-based or titanate-based coupling agent, or an acrylic resin in accordance with a conventional method in consideration of water resistance.

The resin composition of the present invention may contain, if necessary, an antioxidant, a slipping agent, a surfactant, a coloring agent, a softener, a plasticizer, an inorganic filler, a compatibilizer, a stabilizer and the like. (Similarly for the wire coating).

[0024]

Embodiments of the present invention will be described below. A cross section of a cable according to the invention is shown in FIG. The cable 1 includes a core 2 and a sheath 7, the core 2 includes three insulated wires 3, an intermediate 6 and a holding tape 8 around the insulated wire 3, and the insulated wire 3 includes a copper conductor 4 and an insulator 5. .

The copper conductor 4 is made of 1.25 SQ copper stranded wire, the insulator 5 is made of polyethylene, and the outer diameter of the insulated wire core 3 is 2.3 mm. The interposition 6 is made of polypropylene, and the insulated wire core 3 is twisted together with the interposition 6. The sheath 7 is made of the flame-retardant resin composition of the present invention or for comparison, and has a thickness of 1 mm. The outer diameter of cable 1 is 7
mm.

The copper stranded wire serving as the copper conductor 4 is formed by a conventional method.
The core 2 was coated with polyethylene to be the insulator 5 and twisted together with the interposition 6 to form the core 2, and the resin composition to be the sheath 7 was covered by tube extrusion using a 90 mm extruder. The pull-out ratio at the time of extrusion (the ratio S ₁ / S ₀ of the cross-sectional area S ₁ of the material of the base to the cross-sectional area S ₀ of the sheath) is 3.5.
The temperature was 170 ° C., and the linear velocity was 30 m / min.

The resin composition has a capacity of 3
The material was put into a liter kneader, kneaded for 15 minutes, and then a part was press-molded to prepare various test samples, and most were pelletized and used for molding the sheath 7 of the cable 1.

The cable was evaluated as follows. (1) Tensile strength A tensile test according to JISC3005 was performed. The standard value was set to 10 MPa, and those which did not reach this value were rejected.

(2) Heat Deformation A test according to JISC3005 was performed. A load of 10 N was applied to a sheet having a thickness of 2 mm at a temperature of 75 ° C., the deformation was measured, and the deformation ratio was obtained. Those with a deformation rate of less than 50% were accepted.

(3) Processing strain The sheath 7 from which the core 2 has been removed from the cable 1 is allowed to stand on talc, heated at 180 ° C. for 1 hour, and contracted.
Thereafter, the length ratio (%) was determined by the following equation. Length ratio (%) = (length after heating / length before heating) × 100 length ratio 7
0% was set as a standard of the processing strain remaining in the molded article, below it was set as large distortion, and below 70% was set as small distortion.

(4) Kneading processability When performing kneading with a kneader, the kneaded material does not stick to the screw surface and is easily taken out. Those that were difficult to take out were marked as x.

(5) Flame retardancy The completed cable is connected to a metal cable having a diameter of 1 mm in 3c.
A portion simulating a binding portion for fixing the cable was provided at intervals of m. This was used as a combustion test sample and JISC
A 60 degree inclined combustion test according to 3005 was performed. The fire spread time after 30 seconds of indirect flame was measured. The average fire spread time of five combustion tests was less than 60 seconds, and the failure was 60 seconds or more.

Using the ethylene polymer and the flame retardant shown in Table 1, a resin composition used for molding the sheath 7 was prepared. Table 1 shows the results of the above tests for the completed cable together with the resin composition. In Table 1, MI represents a melt index, Mw / Mn represents a molecular weight distribution, and VA represents vinyl acetate. Ultrasen is a trade name of Tosoh Corporation, A1150
Is the product name of JPO.

[0034]

[Table 1]

As shown in Table 1, Examples 1-1, 1-2,
Each of 1-3 and 1-4 is a tensile strength, a heating deformation rate,
The length ratio, kneading workability, and flame retardancy of the work distortion test were all good.

Using the ethylene polymer and the flame retardant shown in Table 2, a resin composition used for molding the sheath 7 was prepared. Table 2 shows the test results of the completed cables together with the resin composition. Bondyne TX8030 is a trade name of Sumitomo Chemical Co., Ltd.

[0037]

[Table 2]

As shown in Table 2, Examples 2-1 and 2-2,
2-3, 2-4, tensile strength, heat deformation rate,
The length ratio, kneading workability, and flame retardancy of the work distortion test were all good.

Using the ethylene polymer and the flame retardant shown in Table 3, a resin composition used for molding the sheath 7 was prepared. Table 3 shows the results of the tests on the completed cable together with the resin composition. Adtex R1200 is a trade name of JPO.

[0040]

[Table 3]

As shown in Table 3, Examples 3-1 and 3-2,
All of 3-3 were good in tensile strength, heat deformation rate, length ratio of working strain test, kneading workability, and flame retardancy.

For comparison, a resin composition used for molding the sheath 7 was prepared using an ethylene polymer having a wide molecular weight distribution shown in Table 4. Table 4 shows the results of the above test for the completed cable together with the resin composition.

[0043]

[Table 4]

Comparative Examples 4-1 to 4-5 using an ethylene polymer having a molecular weight distribution and an Mw / Mn ratio of more than 3.8 are inferior in tensile strength as compared with the above-mentioned examples.
Comparative Example 4- in which the amount of the fatty acid derivative added was small among these
No. 2 has poor kneading processability.

Comparative Example 4-5 using an ethylene polymer having an Mw / Mn ratio showing a molecular weight distribution of more than 3.8 and a melt index of less than 1 also has poor flame retardancy.

The characteristics of Comparative Example 4-6 in which 150 g of aluminum hydroxide was used instead of 100 g of magnesium hydroxide and 1 g of zinc stearate instead of 1 g of lithium hydroxystearate in Comparative Example 4-5 were as follows. Was. Tensile strength (MPa) 7.3 Heat deformation rate (%) 14.5 Length ratio (Working strain test) 41 Kneading workability ○ Flame retardancy Fail

The inferior flame retardancy of Comparative Examples 4-5 and 4-6 using an ethylene polymer having a molecular weight distribution of Mw / Mn ratio of more than 3.8 and a melt index of less than 1 As shown in the strain test, since the sheath has a large residual strain, the sheath is torn at the binding portion at the time of combustion and the core is exposed, resulting in a remarkable increase in the time to spread the fire.

Comparative Example 4-4 using an ethylene polymer having a melt index of more than 10 has strong tackiness and poor kneading processability.

For comparison with the examples, a resin composition used for molding the sheath 7 was prepared using an ethylene polymer and a maleic acid copolymer shown in Table 5. Table 5 shows the results of the above test for the completed cable together with the resin composition.

[0050]

[Table 5]

In Comparative Examples 5-1 and 5-2 in which a maleic acid copolymerized EEA (bondine HX8140) having a melt index of more than 10 was blended, Mw / Mn showing a molecular weight distribution was 3.8 or less (see Table 1). Even if an ethylene polymer having a melt index of 1 or more and 10 or less is used, tensile strength and kneading processability are poor. In particular, Comparative Example 5-2 in which 50% of maleic acid copolymerized EEA was blended
Has a large heat deformation rate.

Even when an ethylene polymer having a melt index of 1 or more is used, Comparative Example 5-3 in which the amount of the stearic acid derivative is large has a significantly lower strength than that of Example 2-1. Further, even when a maleic acid copolymerized EEA (bondine TX8030) having a melt index of 10 or less was blended, the blend amount exceeded 40% in Comparative Example 5-
No. 4 is inferior in kneading processability. An ethylene polymer having a Mw / Mn ratio of 3.8 or less and a melt index of 1 or more;
Maleic acid copolymerized EE having a melt index of 10 or less
Even when A was used, Comparative Example 5-5 in which the amount of the hydroxide flame retardant was large was inferior in tensile strength and kneading processability.

For comparison with the examples, a resin composition used for molding the sheath 7 was prepared using an ethylene polymer and a maleic acid graft polymer shown in Table 6. Table 6 shows the results of the above test for the completed cable together with the resin composition.
It was shown to.

[0054]

[Table 6]

Comparative Example 6 with a small amount of hydroxide flame retardant added
A value of -1 results in large heat deformation and poor flame retardancy.

A cable shown in FIG. 2 was manufactured using the same resin composition as in Examples 1-1 to 3-3. The cable 11 includes a core 12 and a sheath 17, and the core 12 includes two insulated wires 3. The insulated wire core 3 includes a copper conductor 4 and an insulator 5. Examples 1-1 to 3-3 were applied to the sheath 17.
The same resin composition was used. The results were the same as in Examples 1-1 to 3-3.

A cable shown in FIG. 3 was manufactured using the same resin composition as in Examples 1-1 to 3-3. The cable 21 is composed of a core 22 and a sheath 7, and the core 22 is twisted in pairs by two (indicated by a broken-line circle in the figure) and eight (4)
(Pair) of insulated wire cores 23. The insulated wire core 23 includes the copper conductor 4 and the insulator 5 respectively. Example 1 for sheath 7
The same resin compositions as in 1 to 3-3 were used. The results were the same as in Examples 1-1 to 3-3. Example 1
It was confirmed that the flame retardant resin compositions of -1 to 3-3 were also effective as insulators. Further, the effect can be enhanced when used for both the insulator and the sheath.

[0058]

According to the present invention, the ratio of the weight average molecular weight to the number average molecular weight of 100 parts by weight of the flame-retardant resin composition comprising a halogen-free component is 3.8.
By using a composition comprising the following ethylene polymer, 0.2 to 3 parts by weight of a fatty acid or a derivative thereof, and 30 to 200 parts by weight of a metal hydroxide flame retardant, processing distortion after molding is reduced. Thus, a non-halogen flame-retardant resin composition that provides sufficient mechanical strength and excellent flame retardancy is realized.

The reason why the weight-average molecular weight to number-average molecular weight ratio Mw / Mn is 3.8 or less, that is, when an ethylene polymer having a relatively small molecular weight distribution is used, the mechanical strength is excellent is that the tensile strength is reduced. It is presumed that the obtained low-molecular-weight component is eliminated, the long-chain branching contained in the high-molecular-weight component is reduced, and the spherulite size is made uniform.

In the electric wire or cable having an insulator or a jacket made of a non-halogen flame-retardant resin of the present invention, the ratio of the weight-average molecular weight to the number-average molecular weight of 100 parts by weight of the flame-retardant resin is 3.8 or less. And an ethylene polymer of 0.2
3 to 3 parts by weight of a fatty acid or a derivative thereof and 30 to 200 parts by weight of a metal hydroxide flame retardant, it is not sensitive to thermal and mechanical stress, and has sufficient mechanical strength and excellent flame retardancy. A halogen-free flame-retardant electric wire having a property is realized. Furthermore, an electric wire or cable having an insulator or a jacket that does not undergo shrinkage such that the inside is exposed even in the event of burning is realized.

In particular, when an ethylene polymer having a melt index of 1.0 to 10 is used, the effect of securing mechanical strength and preventing residual strain during processing is great. This is considered to be due to the fact that the processing strain is reduced by improving the fluidity. When the fluidity increases, the surface of the kneading machine tends to adhere, but 0.2 to 3 parts by weight of the fatty acid or its derivative functions as a lubricant, so that the kneading processability is not impaired.

As the base polymer, the molecular weight distribution is small (the ratio of the weight average molecular weight to the number average molecular weight, Mw / M
n is 3.8 or less) By using a mixture of 97 to 60% by weight of an ethylene copolymer and 3 to 40% by weight of an acid-modified polyolefin having a melt index of 10 or less, heat deformation of the resin composition can be reduced. Can be.
This is presumed to be because the acid anhydride functional group of the acid-modified polymer adheres to the surface of the metal hydroxide, so that the entire system is reinforced and the heat resistance is improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an embodiment of an electric wire / cable using the present invention.

FIG. 2 is a sectional view showing an embodiment of an electric wire / cable using the present invention.

FIG. 3 is a sectional view showing an embodiment of an electric wire / cable using the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cable 2 Core 3 Insulated wire core 4 Copper conductor 5 Insulator 6 Intervention 7 Sheath 8 Holding tape 11 Cable 12 Core 17 Sheath 21 Cable 22 Core 23 Insulated wire core

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01B 3/44 H01B 3/44 M 7/295 7/34 B F term (Reference) 4J002 BB031 BB051 BB061 BB062 BB071 BB151 BB171 BB211 BG042 BG052 BG062 BH022 BN051 BN052 DA057 DE077 DE087 DE097 DE127 DE147 DE287 DJ037 EG026 EG036 EG046 EW047 EW127 FD137 GQ01 5G303 AA06 AA10 AB12 CA01 AB02 BA01 BA02 CA01 CB13 CC03 CD13 5G315 CA03 CB01 CC08 CD04 CD14

Claims (7)

[Claims] 1. A flame-retardant resin composition comprising a halogen-free component, wherein 100 parts by weight of an ethylene polymer having a weight-average molecular weight to number-average molecular weight ratio of 3.8 or less; A flame-retardant resin composition comprising 3 parts by weight of a fatty acid or a derivative thereof and 30 to 200 parts by weight of a flame retardant comprising a metal hydroxide. 2. The flame-retardant resin composition according to claim 1, wherein the melt index of the ethylene polymer is 1.0 to 10. 3. The flame-retardant resin according to claim 1, wherein the ethylene polymer is an ethylene-vinyl acetate copolymer having a vinyl acetate content of 10 to 50 mol% and a melt index of 1.0 to 10. Composition. 4. A flame-retardant resin composition comprising a halogen-free component, comprising: 100 parts by weight of a mixture of an ethylene copolymer and an acid-modified polyolefin; and 0.2 to 3 parts by weight of a fatty acid or a derivative thereof. And 30 to 200 parts by weight of a flame retardant comprising a metal hydroxide, wherein the ethylene copolymer has a weight average molecular weight to number average molecular weight ratio of 3.8 or less and a melt index of 10 or less. Having a vinyl acetate content of 10-50 mol%
Wherein said acid-modified polyolefin has a melt index of 10 or less; said mixture comprises 97 to 60% by weight of said ethylene copolymer and 3 to 40% by weight of said acid-modified A flame-retardant resin composition, which is a mixture with a polyolefin. 5. The flame-retardant resin composition according to claim 4, wherein the acid-modified polyolefin is an ethylene-ethyl acrylate-maleic anhydride terpolymer. 6. An electric wire / cable comprising an insulated wire in which a conductor is covered with an insulator, wherein the insulator or the sheath is composed of 100 parts by weight of a weight average molecular weight with respect to a number average molecular weight. Flame retardant resin composition comprising an ethylene polymer having a ratio of 3.8 or less, 0.2 to 3 parts by weight of a fatty acid or a derivative thereof, and 30 to 200 parts by weight of a flame retardant comprising a metal hydroxide. An electric wire or cable formed by an object. 7. The method according to claim 1, wherein the ethylene polymer is 1.0 to 1
7. The wire or cable of claim 6, having a melt index of zero.