JPH0977918A - Flame-retardant resin composition and electric wire using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a flame-retardant resin composition having high flame retardancy and practical-level tensile strength at break and to produce an electric wire using the same. SOLUTION: This flame-retardant resin composition comprises a polyolefin resin (a) obtained by polymerizing at least one olefin in the presence of a catalyst composition containing a metal coordinated complex and an activated cocatalyst, an inorganic metal hydrate (b) and a carboxylic polyolefin resin (c). The mixing ratio (a)/(c) should be 70/30 to 99/1. The amount of component (b) used is above 200 to 300 pts.wt. per 100 pts.wt. total of components (a) and (c). The composition has a tensile strength at break of 1.02kg/mm<2> or above and an oxygen index of 36 or above. The objective electric wire is prepared by coating a conductor with this composition.

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 mainly composed of a polyolefin resin, and an electric wire such as an insulated electric wire or a cable using the composition as an insulating coating.

[0002]

2. Description of the Related Art There are various synthetic resins used for insulation coating in insulated wires and cables, but especially for applications requiring oil resistance, chemical resistance, low temperature characteristics, etc. For example, low density polyethylene (LD
PE), linear low-density polyethylene (L-LDPE), ultra-low-density polyethylene (VLDPE), and other polyolefin resins are preferably used.

Further, since the above-mentioned polyolefin resin itself does not have flame retardancy, in applications where flame retardancy is required, a metal inorganic hydrate which is a flame retardant based on the polyolefin resin, A flame-retardant resin composition containing a polyolefin resin containing a carboxyl group in the molecule and other additives is used. Examples of the inorganic metal hydrate to be added to the flame-retardant resin composition include aluminum hydroxide and magnesium hydroxide.

Further, the polyolefin resin containing a carboxyl group in the molecule improves the affinity of the above-mentioned metal inorganic hydrate for the polyolefin resin, and the tensile rupture strength of the composition prepared by blending the metal inorganic hydrate. Of the metal inorganic hydrate is extruded on the surface of the product, so-called bleeding is prevented, for example, in the main chain of the polyolefin system, as a side chain, the metal The thing etc. which introduced the said carboxyl group which has affinity with an inorganic hydrate are mentioned.

[0005]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention In the above conventional polyolefin-based flame-retardant resin composition,
36 in terms of oxygen index specified in IS K 7201
Further, in order to obtain a high level of 500 mm or less in terms of the combustion length in the vertical tray combustion test specified in IEEE383, the metal inorganic hydrate is composed of a polyolefin resin and a polyolefin resin containing a carboxyl group. It is necessary to blend in a large amount of more than twice the weight ratio with respect to the total amount.

However, a polyolefin-based flame-retardant resin composition containing a large amount of a metal inorganic hydrate as described above is
Despite blending a polyolefin resin containing a carboxyl group, its tensile breaking strength is within a practical range where the quality of the insulation coating of the electric wire can be maintained 1.02k
Since it is much lower than the level of g / mm ² or more,
An insulating coating made of such a composition is likely to cause breakage,
There is a problem that it cannot be put to practical use.

Further, for example, a polyolefin-based copolymer such as an ethylene-ethyl acrylate copolymer (EEA) or an ethylene-vinyl acetate copolymer (EVA) has a tensile rupture of the composition as compared with the above-mentioned polyolefin-based resin. It is widely known that the strength can be improved, but in a system in which a large amount of metal inorganic hydrate is blended as described above, the tensile rupture strength of the composition is much lower than the above range. As a result, there is a problem that it cannot be put to practical use.

An object of the present invention is to provide a flame-retardant resin composition having a high level of flame retardancy and a practical level of tensile strength at break.
An object of the present invention is to provide an electric wire using the same and having an insulating coating excellent in both of the above properties.

[0009]

[Means for Solving the Problems] In order to solve the above problems, the inventors examined various polyolefin resins. As a result, at least one olefin is
When an elastic and substantially linear polyolefin-based resin polymerized in the presence of a catalyst composition containing a metal coordination complex such as a metallocene and an activating cocatalyst is used, the aforementioned metal inorganic hydrate is used. In a system containing a large amount of oxygen, the oxygen index was 36 or more, and the combustion length in the vertical tray combustion test was 500.
High flame retardancy less than mm and tensile breaking strength 1.02kg
It was found that a flame-retardant resin composition having a practical level of tensile rupture strength of not less than 1 mm ² / mm ² was obtained, and as a result of further studying the blending ratio of the above-mentioned polyolefin resin and other components, this invention Has been completed.

That is, the flame-retardant resin composition of the present invention is
(a) a polyolefin resin obtained by polymerizing at least one olefin in the presence of a catalyst composition containing a metal coordination complex and an activating cocatalyst; and (b) a metal inorganic hydrate which is a flame retardant. , (C) the above-mentioned inorganic metal hydrate (b), in order to improve the affinity for the polyolefin resin (a), a polyolefin resin containing a carboxyl group in the molecule, and the above polyolefin resin When the compounding ratio of (a) and the polyolefin resin (c) containing a carboxyl group is in the range of a / c = 70/30 to 99/1 by weight, the polyolefin resin (a) and the carboxyl group are The content of the metal inorganic hydrate (b) is more than 200 parts by weight and 300 parts by weight or less with respect to the total amount of 100 parts by weight of the polyolefin resin (c) contained, and the tensile breaking strength is 1.02 kg / mm.
It is characterized by having an oxygen index of ² or more and an oxygen index of 36 or more.

The electric wire of the present invention is characterized by having an insulating coating made of the flame-retardant resin composition of the present invention.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION First, the flame-retardant resin composition of the present invention will be described. The flame-retardant resin composition of the present invention is
As described above, (a) a polyolefin resin obtained by polymerizing at least one olefin in the presence of a catalyst composition containing a metal coordination complex and an activating cocatalyst, and (b) a flame retardant metal. It contains an inorganic hydrate and (c) a polyolefin resin containing a carboxyl group in the molecule.

Of these, the polyolefin-based resin (a) is not limited to this, for example, JP-A-6-306.
An elastic and substantially linear polyolefin resin disclosed in JP-A No. 121 and JP-A-7-500622 is preferably used. Such an elastic and substantially linear polyolefin-based resin is, for example, ethylene or an α-olefin having about 3 to 20 carbon atoms alone, or ethylene and α-olefin having about 3 to 20 carbon atoms.
It is produced by polymerizing two or more kinds of olefins in combination in the presence of a catalyst composition containing a metal coordination complex such as a metallocene and an activating cocatalyst, and has a density of 0.8.
About 6 to 0.94, and 0.01 to 3 per 1000 carbon atoms constituting the main chain, preferably 0.01 to
One, more preferably 0.5 to 1 and having 6 carbon atoms
It has the above long branched chains.

The above-mentioned polyolefin resin has processability similar to that of highly branched low density polyethylene (ordinary LDPE) and is a heterogeneous linear polymer obtained by polymerizing ethylene and α-olefin with a Ziegler catalyst (for example, L-LDPE, etc.) and the same strength and toughness,
Moreover, as described above, it has a completely different structure from LDPE, L-LDPE, or VLDPE in which ethylene and α-olefin are polymerized by a Ziegler catalyst, like L-LDPE.

Specific examples of the above-mentioned elastic and substantially linear polyolefin resin are not limited to these, but include, for example, the Dow Chemical Company (USA).
Chemical Co. ) Product name "AFFIN
The ITY (affinity) series can be mentioned. The above series is a copolymer of ethylene and 1-octene, and various grades are provided depending on the difference in the proportion of octene.

Of these, the one that is particularly preferably used in the present invention is, for example, the trade name AFFINITY.
PF1140 [octene content 14.5% by weight, melt index (MI) value 1.6, density 0.895, tensile breaking strength 4.5 kg / mm ² ], AFFINITY PL1
880 [octene 12% by weight, melt index (MI) value 1, density 0.902, tensile breaking strength 4.8 k
g / mm ² ], AFFINITY FW1650 [octene content 12.0% by weight, melt index (MI) value 3, density 0.902, tensile breaking strength 3.8 kg / m]
m ² ]. Since these polyolefin-based resins have a low MI value and excellent workability, it is easy to manufacture an electric wire by extrusion molding or the like. In addition, these polyolefin-based resins have an advantage that the electric wire can be lightened because of their relatively low density.

Next, a metal inorganic hydrate (b) which is a flame retardant.
As the material, for example, aluminum hydroxide, magnesium hydroxide or the like can be used. As such a metal inorganic hydrate, any one having a usual shape such as powder can be used. The above metal inorganic hydrate
As described above, the blending amount of (b) is the polyolefin resin (a) and the polyolefin resin containing a carboxyl group.
The total amount of (c) and 100 parts by weight is more than 200 parts by weight and limited to 300 parts by weight or less.

When the compounding amount of the inorganic metal hydrate (b) is 200 parts by weight or less, the tensile rupture strength of the composition is improved, but
When the oxygen index is less than 36, the high flame retardancy of 500 mm or less in the vertical tray combustion test cannot be obtained. On the contrary, when it exceeds 300 parts by weight, the flame retardancy of the composition is further increased. Although improved, the tensile strength at break becomes less than 1.02 kg / mm ² .

When the flame retardancy of the composition is emphasized, the compounding amount of the inorganic metal hydrate (b) is preferably as large as possible within the above range, and the upper limit of the range, that is, 300 parts by weight. Is most preferred. In this case, the metal inorganic hydrate
As the blending amount of (b) increases, the tensile breaking strength of the composition tends to decrease.
Due to the action of (a), the composition is
1.02 kg / mm even if the compounding amount of (b) is the upper limit
Since it has a tensile strength at a practical level of ² or more, there is no problem in practical use.

Further, if the compounding amount of the polyolefin resin (c) containing a carboxyl group described later is increased, the decrease in the tensile breaking strength of the composition due to the increase of the compounding amount of the metal inorganic hydrate (b) is reduced. It is possible to cover to some extent.
The above-mentioned metal inorganic hydrate (b), polyolefin resin (a)
As a polyolefin-based resin (c) containing a carboxyl group in its molecule to improve its affinity for, as described above, the same polyolefin-based main chain has an affinity for a metal inorganic hydrate as a side chain. Various conventionally known resins such as those having a carboxyl group introduced therein can be used. More specifically, a copolymer obtained by grafting maleic anhydride onto the main chain of polyethylene or the like, for example, N polymer L6031 manufactured by Nisseki Chemical Co., Ltd., Admer NE065 manufactured by Mitsui Petrochemical Co., Ltd. Alternatively, or a copolymer obtained by copolymerizing maleic anhydride in the main chain, for example, Bondine AX-839 under the trade name of Sumitomo Chemical Co., Ltd.
0 and the like are preferably used as the above-mentioned polyolefin resin (c) containing a carboxyl group.

In the flame-retardant resin composition of the present invention,
As described above, the blending ratio of the polyolefin resin (a) and the carboxyl group-containing polyolefin resin (c) is limited to the weight ratio a / c = 70/30 to 99/1. . When the amount of the polyolefin resin (c) containing a carboxyl group is less than the above range of the compounding ratio, the addition of the resin (c) causes the affinity of the metal inorganic hydrate (b) to the polyolefin resin (a). The effect of improving the property is not obtained, and even if the compounding amount of the metal inorganic hydrate (b) is 200
Even if the value is as close as possible to parts by weight, the tensile breaking strength is 1.
It will be less than 02 kg / mm ² . On the contrary, when the amount of the polyolefin resin (c) containing a carboxyl group is more than the range of the above mixing ratio, the processability of the composition is lowered because the melt index value of the resin (c) is high,
It becomes impossible to perform extrusion processing.

The blending ratio of the above-mentioned polyolefin resin (c) containing a carboxyl group is preferably as high as possible within the above range in order to improve the tensile breaking strength of the composition. In particular, as mentioned above, in order to improve the flame retardancy of the composition, the compounding amount of the metal inorganic hydrate (b) is set to 300.
When the amount is increased to parts by weight or in the vicinity thereof, the polyolefin resin (c) containing a carboxyl group is added to the polyolefin resin (a) at the upper limit value (a /
b = 70/30) or close to it.

In this case, the processability of the composition tends to be slightly lowered, but this is not a problem in practical use.
For example, in the case of extrusion processing, the range can be sufficiently covered by adjusting the extrusion temperature and the extrusion pressure. The flame-retardant resin composition of the present invention contains, in addition to the above-mentioned three components, various additives such as carbon black, a lubricant, a filler, a flame-retardant aid, and an antiaging agent in the same proportion as in the conventional case. May be included.

The flame-retardant resin composition of the present invention is produced by mixing the above-mentioned components in a predetermined ratio, melting and kneading. Next, the electric wire of the present invention will be described. Examples of the electric wire of the present invention include an insulated electric wire in which an insulating coating made of the flame-retardant resin composition of the present invention is formed on the surface of a conductor, a cable in which a plurality of insulated electric wires are combined, and the like.

As the conductor, any of known conductor materials such as copper, annealed copper, silver, nickel-plated annealed copper and tin-plated annealed copper can be used. The above wire is
It can be manufactured in a conventional manner. For example, for an insulated wire, the surface of the conductor may be coated with the flame-retardant resin composition of the present invention by extrusion molding or the like. The cable is
A plurality of insulated wires may be manufactured by a usual method suitable for the structure of the cable, such as twisting the insulated wires together with other wire materials as necessary and coating the sheath.

In the electric wire, the thickness of the insulating coating, the diameter of the conductor, etc. are not particularly limited, and any dimensions may be adapted to the standard of the electric wire. Since the electric wire of the present invention has the insulating coating formed of the flame-retardant resin composition of the present invention, it has a high flame retardancy and a practical level of tensile rupture strength.

The insulating coating made of a flame-retardant resin composition has its heat-deformability improved, and when it is subjected to an external force under heating, the insulation is deteriorated or the conductor is short-circuited. It may be crosslinked in order to prevent the occurrence of.

By carrying out such crosslinking, the tensile breaking strength of the insulating coating is further improved.

[0029]

The present invention will be described below with reference to examples and comparative examples. Example 1 An ethylene-1-octene copolymer (EO, which is a polyolefin resin (a), trade name “AFFINITY” described above.
PL1880 "Octene 12% by weight, density 0.90
2) 92 parts by weight, 250 parts by weight of magnesium hydroxide which is a metal inorganic hydrate (b), and a polyolefin resin (c) containing a carboxyl group (the above-mentioned trade name "N Polymer L6
031 ") and 8 parts by weight of carbon black and 5 parts by weight of carbon black were melted and kneaded to produce a flame-retardant resin composition. Example 2 As a polyolefin resin (a), the octene content was 14.
An ethylene-1-octene copolymer having 5% by weight and a density of 0.895 (EO, trade name “AFFINIT
Example 1 except that Y PF1140 ") was used.
A flame-retardant resin composition was produced in the same manner as. Example 3 As a polyolefin-based resin (a), an ethylene-1-octene copolymer having a octene content of 12% by weight and a density of 0.902 (EO, trade name “AFFINITY” above).
A flame-retardant resin composition was produced in the same manner as in Example 1 except that FW1650 ") was used. Comparative Examples 1 to 5 A flame-retardant resin composition was produced in the same manner as in Example 1 except that the following conventional polyolefin resin was used instead of the polyolefin resin (a).

Comparative Example 1: LDPE (trade name "LEXRON F22" manufactured by Nisseki Chemical Co., Ltd.) Comparative Example 2: L-LDPE (trade name "Linirex BF3710" manufactured by Nisseki Chemical Co., Ltd.) Comparative Example 3 : VLDPE (trade name "Excellen VL200" manufactured by Sumitomo Chemical Co., Ltd.) Comparative Example 4: EEA (trade name "Rexlon A1150" manufactured by Nisseki Chemical Co., Ltd.) Comparative Example 5: EVA (manufactured by Mitsui DuPont Co., Ltd.) Trade name "Evaflex V987") The following tests were performed on the flame-retardant resin compositions produced in the above Examples and Comparative Examples, and the characteristics were evaluated. Tensile Breaking Strength Measurement A test piece prepared from the flame-retardant resin composition of each of Examples and Comparative Examples was pulled at a tensile speed of 200 m using an Instron tensile tester.
The breaking strength when pulled in the longitudinal direction at a speed of m / min was measured. Oxygen index measurement The oxygen index (O.I.) of the flame-retardant resin compositions of Examples and Comparative Examples.
I. ) Was measured according to JIS K7201 to evaluate the flame retardancy of the composition.

Further, after pelletizing the flame-retardant resin composition produced in each of Examples and Comparative Examples by a pelletizer,
By performing extrusion molding using an extrusion molding machine, an insulating coating made of the flame-retardant resin composition was formed on the surface of the conductor to manufacture an insulated wire having a conductor size of 22 mmsq. Then, the insulated wire was subjected to the following tests to evaluate the characteristics of the above composition after electric wire processing. Vertical tray burning test The burning length of the insulated wire in the vertical tray burning test was measured according to IEEE383.

The above results are shown in Tables 1 to 3.

[0033]

[Table 1]

[0034]

[Table 2]

[0035]

[Table 3]

Among the examples and comparative examples shown in the above tables,
LDPE, L-LDPE, as polyolefin resin
It was found that Comparative Examples 1 to 5 using VLDPE, EEA and EVA all do not have a practical level of strength because the tensile breaking strength is less than 1.02 kg / mm ² . On the other hand, Examples 1 to 3 all have an oxygen index of 36 or more and a combustion length of 5 in the vertical tray combustion test.
It was confirmed that it has a high flame retardancy since it is not more than 00 mm, and has a practical level of strength because it has a tensile breaking strength of not less than 1.02 kg / mm ² . Examples 4 and 5, Comparative Examples 6 and 7 Magnesium hydroxide which is a metal inorganic hydrate (b) based on 100 parts by weight of the total amount of the polyolefin resin (a) and the carboxyl group-containing polyolefin resin (c). A flame-retardant resin composition was produced in the same manner as in Example 1 except that the compounding amount of was set as follows.

Comparative Example 6: 180 parts by weight Example 4: 200 parts by weight Example 5: 300 parts by weight Comparative Example 7: 310 parts by weight Comparative Example 7: 310 parts by weight The flame-retardant resin composition produced in each of the above Examples and Comparative Examples, and each. Each of the above-mentioned tests was performed on the insulated electric wire having a conductor size of 22 mmsq, which was manufactured in the same manner as above from the flame-retardant resin compositions of Examples and Comparative Examples, and the characteristics were evaluated. The results are shown in Tables 4 and 5 together with the results of Example 1 above.

[0038]

[Table 4]

[0039]

[Table 5]

Among the examples and comparative examples shown in the above tables,
In Comparative Example 6 in which the content of magnesium hydroxide is less than 200 parts by weight, the oxygen index is less than 36 and the combustion length in the vertical tray combustion test exceeds 500 mm, so the flame retardancy does not reach a high level. I understand. Further, Comparative Example 7 in which the amount of magnesium hydroxide added exceeded 300 parts by weight had a tensile strength at break of less than 1.02 kg / mm ² , so it was found that it did not have a practical level of strength. On the other hand, in each of Examples 1, 4, and 5,
With an oxygen index of 36 or more and a combustion length of 500 mm or less in a vertical tray combustion test, it has high flame retardancy and a tensile breaking strength of 1.02 kg / mm ^2.
From the above, it was confirmed that it has a practical level of strength.

Comparing the above examples, it was found that the flame retardance was improved as the blending amount of magnesium hydroxide was increased, but the tensile breaking strength tended to be lowered. Examples 6 and 7, Comparative Example 8 Examples except that the compounding ratio (weight ratio) a / c of the polyolefin resin (a) and the carboxyl group-containing polyolefin resin (c) was set as follows: A flame-retardant resin composition was produced in the same manner as in 5.

Example 6: a / c = 75/25 Example 7: a / c = 70/30 Comparative Example 8: a / c = 65/35 The flame-retardant resin produced in each of the above Examples and Comparative Examples. The above-mentioned respective tests were carried out on the insulated wire having a conductor size of 22 mmsq, which was produced from the composition and the flame-retardant resin compositions of Examples and Comparative Examples in the same manner as above, and the characteristics thereof were evaluated. The results are shown in Tables 6 and 7 together with the results of Example 5 above.

The composition of Comparative Example 8 in which the compounding ratio of the carboxyl group-containing polyolefin resin (c) was more than the range of the claims was poor in workability and could not be manufactured into an insulated electric wire by extrusion. Abandoned the vertical tray burning test.

[0044]

[Table 6]

[0045]

[Table 7]

Of the examples and comparative examples shown in the above tables,
In Comparative Example 8 in which the compounding ratio of the polyolefin-based resin (c) containing a carboxyl group was large, the workability of the composition was poor as described above, and the insulated wire could not be manufactured by extrusion. On the other hand, all of Examples 5 to 7 had good workability, and the insulated wire could be manufactured by extrusion.

In each of the examples, the oxygen index was 36 or more and the burning length in the vertical tray burning test was 500 m.
Since it is m or less, it has been confirmed that it has a high level of flame retardancy and a practical level of strength because the tensile breaking strength is 1.02 kg / mm ² or more. Further, comparing the examples, it was found that the tensile breaking strength can be improved by increasing the compounding ratio of the polyolefin-based resin (c) containing a carboxyl group.

[0048]

As described above in detail, according to the present invention, a flame-retardant resin composition having a high level of flame retardancy and a practical level of tensile rupture strength, and the above-mentioned characteristics using the same An electric wire having an excellent insulation coating is obtained.

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Claims (3)

[Claims] 1. A polyolefin resin obtained by polymerizing at least one olefin in the presence of a catalyst composition comprising (a) a metal coordination complex and an activating cocatalyst, and (b) a flame retardant metal. Inorganic hydrate, (c) Inorganic hydrate (b) of the above, polyolefin resin
In order to improve the affinity for (a), a polyolefin-based resin containing a carboxyl group in the molecule, containing the above polyolefin-based resin (a), and a polyolefin-based resin containing a carboxyl group (c) The ratio is a /
In the range of c = 70/30 to 99/1, a metal inorganic hydrate with respect to 100 parts by weight of the total amount of the polyolefin resin (a) and the carboxyl group-containing polyolefin resin (c).
A flame-retardant resin composition characterized in that the compounding amount of (b) is in the range of more than 200 parts by weight and 300 parts by weight or less, and the tensile breaking strength is 1.02 kg / mm ² or more and the oxygen index is 36 or more. Stuff. 2. A polyolefin resin is ethylene and 1-
The flame-retardant resin composition according to claim 1, which is a copolymer with octene. 3. An electric wire having an insulating coating made of the flame-retardant resin composition according to claim 1 or 2.