JP2001040153A - Non-halogen flame-retardant polyolefin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To impart a composition mainly composed of a resin free from a halide with sufficient mechanical characteristics and flame-retardant characteristics which meet the single wire core vertical burning test by admixing a metal hydroxide with an olefinic resin and kneading with the admixture a silicone rubber having incorporated therein titanium oxide. SOLUTION: A non-halogen flame-retardant polyolefin is obtained by kneading 100 pts.wt. of a polyolefin elastomer with 80-170 pts.wt. of a metal hydroxide using a mixing roll at 120 deg.C. A flame-retardant silicone rubber is obtained by kneading 100 pts.wt. of a silicone rubber with 3-15 pts.wt. of titanium oxide using a mixing roll at 50 deg.C. Then, a non-halogen flame-retardant polyolefin composition is obtained by kneading 100 pts.wt. of the flame-retardant polyolefin with 50 pts.wt. of the flame-retardant silicone rubber. The resultant flame- retardant composition has a flame-retardant characteristics which meet the single wire core vertical burning test according to ICEA S61-402 (NEMA WC5).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an olefin resin composition and, more particularly, to a non-halogen flame-retardant polyolefin composition which meets the wire-to-core vertical burn test specified by ICEA and can obtain sufficient mechanical properties. About.

[0002]

2. Description of the Related Art In a conventional thermoplastic resin composition using a polyvinyl chloride resin composition, for example, when an electric wire or cable is burned for incineration and disposal, the polyvinyl chloride resin composition is corroded. There is a problem that hydrogen chloride gas having properties is generated. Therefore, in recent years, attempts have been made to use an olefin-based resin composition such as polyethylene as an insulator without using a halide, as an insulator for electric wires and cables in places where high temperatures are generated, such as a wire harness of an automobile. Since this olefin-based resin composition does not have flame retardancy by itself, it is made to have flame retardancy by mixing a metal hydroxide such as magnesium hydroxide.

[0003] In addition, electric wires and cables using an olefin-based resin composition have standards in both domestic and foreign countries. In recent years, electric wires and cables that conform to foreign standards have been required. According to foreign standards, vertical test
There is an EA standard. This ICEA standard wire-core one-row vertical combustion test (ICEA S61-402 (NEMA WC5)
The vertical combustion test is performed in the following manner. First, a wire of about 560 mm length, which is a sample, was fixed and hung above the metal box, and a 9.5 mm caliber, tyrile burner with a 102 mm length spark plug from the air intake to the tip was attached. 2
Set on a 0 ° inclined table, use city gas, the burner flame length is 127 mm, and the length of the inner blue flame is 38.1 mm
And adjust the position with the sample so that the tip of the blue flame of the burner hits the sample. At the top of the sample, a thickness of 0.
A kraft paper of 127 mm and width of 12.7 mm is wrapped once around the sample, and a length of 19.0 mm is put out to set an indicator. After setting in this way, open the main valve of the burner with the ignition plug of the burner ignited,
The operation of closing the original valve and resting for 15 seconds after applying the sample to the sample for 15 seconds is repeated four times, and after applying the flame to the sample five times, the case where 25% of the kraft paper burns is determined to be fire spread. If the sample continued to burn for more than a minute, it was rejected.

[0004] Such an ICEA S61-402 (N
In order to pass the EMA WC5) wire-core one-row vertical burn test, in the case of a polymer material for insulation coating of electric wires and cables in which a conventional olefin resin is made non-halogen flame-retardant,
A large amount of metal hydroxides such as magnesium hydroxide and aluminum hydroxide, which are flame retardants, have been added.

[0005]

However, when this metal hydroxide such as magnesium hydroxide is mixed with an olefin resin, the metal hydroxide is a foreign substance from the viewpoint of the olefin resin, and the metal hydroxide is inferior to the composition structure of the olefin resin composition. Even so, it can break the strong bond. That is, when a metal hydroxide such as magnesium hydroxide is blended, the rigidity of the structure of the olefin resin composition is broken and the composition becomes brittle. For this reason, if a large amount of metal hydroxide such as magnesium hydroxide is mixed, there is a problem that mechanical properties (tensile properties) are reduced. The amount of hydroxide must be reduced.

[0006] However, the insulator mainly composed of such an olefin-based resin composition needs to be mixed with a large amount of a metal hydroxide such as magnesium hydroxide in order to obtain high flame retardancy. However, if a large amount of a metal hydroxide such as magnesium hydroxide is mixed, the abrasion resistance to mechanical shock is reduced and the insulation (volume resistivity) is reduced. In order to suppress a decrease in the property (volume resistivity), the amount of metal hydroxide such as magnesium hydroxide to be mixed must be reduced. If the amount of the metal hydroxide such as magnesium hydroxide is reduced, ICEA S61-402 required in recent years can be reduced.
It becomes impossible to obtain flame retardant characteristics conforming to (NEMA WC5) wire-core, single-row, vertical combustion test characteristics.

[0007] It is an object of the present invention to obtain a sufficient mechanical property by suppressing the compounding of a metal hydroxide, comprising an olefin-based resin containing no halide as a main component.
61-402 (NEMA WC5) to obtain flame retardant characteristics conforming to the characteristics of a single-core vertical burn test.

[0008]

In order to achieve the above object, the non-halogen flame-retardant polyolefin composition according to the first aspect of the present invention contains a metal hydroxide and a titanium oxide in an olefin resin. It is formed by kneading silicone rubber. The olefin-based resin includes polypropylene, polyethylene, ethylene-vinyl acetate copolymer and ethylene-ethyl acrylate copolymer, and can be composed of any one or a mixture of two or more thereof. Other olefin resins that can be used in the halogen-free flame-retardant polyolefin composition include linear low-density polyethylene, low-density polyethylene, ethylene-ethyl acrylate copolymer, ethylene-methyl methacrylate copolymer, ethylene-methacrylic copolymer. There are acid copolymers, high density polyethylene, polypropylene, metallocene linear low density polyethylene, metallocene ultra low density polyethylene, and ethylene-propylene copolymer. The titanium oxide compounded in the silicone rubber is for improving the flame retardancy, and ensures the flame retardancy when the amount of the metal hydroxide is suppressed to a small level. According to the first aspect of the present invention having such a configuration, the olefin-based resin is a main component, no halide is contained, and sufficient mechanical properties are obtained by suppressing the compounding of the metal hydroxide. By kneading a silicone rubber containing titanium oxide, ICEA S61-402 (NEMA W
It is possible to obtain flame retardant characteristics conforming to the characteristics of the single core vertical flame test of C5).

In order to achieve the above object, a halogen-free flame-retardant polyolefin composition according to claim 2 is obtained by mixing titanium oxide with 100 parts by weight of a flame-retardant polyolefin containing a metal hydroxide. 5 burning silicone rubber
It is constituted by kneading 0 parts by weight. The reason why the amount of the flame-retardant silicone rubber containing titanium oxide was 50 parts by weight with respect to 100 parts by weight of the flame-retardant polyolefin containing metal hydroxide was that titanium oxide was compounded. If the flame-retardant silicone rubber is added in an amount exceeding 50 parts by weight, the amount of the metal hydroxide as a whole increases, resulting in insufficient mechanical properties. If the amount is less than the part, the amount of the metal hydroxide as a whole decreases,
This is because the flame retardancy is insufficient. According to the second aspect of the present invention having such a configuration, the olefin resin is a main component, the halide is not included, and sufficient mechanical properties are obtained by suppressing the blending of the metal hydroxide. By kneading a silicone rubber containing titanium oxide, ICEA S61-402 (NEMA W
It is possible to obtain flame retardant characteristics conforming to the characteristics of the single core vertical flame test of C5).

In order to achieve the above object, the halogen-free flame-retardant polyolefin composition according to claim 3 is characterized in that a flame-retardant polyolefin is used in an amount of 120 to 120 parts by weight of a metal hydroxide with respect to 100 parts by weight of a polyolefin elastomer.
It is manufactured by kneading with a mixing roll at ℃. In order to constitute the flame-retardant polyolefin, the compounding amount of the metal hydroxide is set to 80 to 170 parts by weight with respect to 100 parts by weight of the polyolefin elastomer, because the compounding amount of the metal hydroxide is less than 80 parts by weight. This is because flame retardancy cannot be obtained, and if the compounding amount of the metal hydroxide exceeds 170 parts by weight, necessary mechanical characteristics cannot be obtained. The mixing roll is a machine for plasticizing or kneading the compounding material by applying a mechanical shearing force to a rubber or plastic material between two rolls, and a flame-retardant polyolefin is used for the polyolefin elastomer 100 by using the mixing roll. The metal hydroxide is blended in the range of 80 to 170 parts by weight with respect to parts by weight, and heated to 120 ° C. and kneaded. With this configuration, according to the third aspect of the invention, it is possible to obtain sufficient flame-retardant properties and sufficient mechanical properties as a flame-retardant polyolefin.

[0011] In order to achieve the above object, the non-halogen flame-retardant polyolefin composition according to claim 4 is characterized in that the metal hydroxide comprises magnesium hydroxide, aluminum hydroxide,
It is composed of any one of zirconium hydroxide, calcium hydroxide and barium hydroxide or a mixture of two or more thereof. The metal hydroxide is an inorganic flame retardant used for an olefin resin, such as magnesium hydroxide, aluminum hydroxide, or calcium hydroxide. When the olefin-based resin composition is burned by blending the metal hydroxide with the olefin-based resin, water of crystallization contained in the blended metal hydrate blows out to extinguish the fire. It has the effect of making it difficult to burn and carbonizing the cinders even when it burns to give shape retention. As described above, according to the fourth aspect of the invention, it is possible to secure the mechanical characteristics of the electric wire / cable.

[0012] In order to achieve the above object, the halogen-free flame-retardant polyolefin composition according to claim 5 comprises a flame-retardant silicone rubber and 100 parts by weight of silicone rubber.
It is manufactured by kneading 3 to 15 parts by weight of titanium oxide with a mixing roll at 50 ° C. Silicone rubber has a main chain composed of siloxane bonds,
It is a rubber-like elastic material in which linear polymers having organic substituents such as phenyl group and vinyl group are crosslinked with each other. The amount of titanium oxide was 5 to 15 parts by weight with respect to 100 parts by weight of silicone rubber to constitute the flame-retardant silicone rubber. Cannot obtain sufficient flame-retardant properties even if it is obtained. If the compounding amount of titanium oxide exceeds 15 parts by weight, sufficient mechanical properties are obtained even if required fuel properties can be obtained. Because they cannot do it. As described above, according to the invention described in claim 5, it is possible to secure the flame-retardant characteristics of the electric wire / cable.

[0013] In order to achieve the above object, a halogen-free flame-retardant polyolefin composition according to claim 6 is obtained by crosslinking the flame-retardant polyolefin and the flame-retardant silicone rubber.

In the crosslinking method, a γ-ray or an electron beam is used as a radiation source, and a radical is generated in a molecule by irradiating the olefin resin with the γ-ray or an electron beam. Irradiation cross-linking to form cross-linking, organic peroxide that does not decompose at the plasticization temperature of olefin resin is blended, and organic peroxide is decomposed by exposing it to high temperature and high pressure simultaneously with or after molding. A radical is generated, and a crosslinking reaction between molecules is promoted by the radical. After an organic peroxide crosslinking, a vinyl silane compound is subjected to a graft addition reaction to an olefin resin, a silanol condensation catalyst is added to the graft mer, and after forming processing, water content is reduced. After exposure to an atmosphere, the alkoxysilanes at the graft ends hydrolyze and then crosslink between the dealcoholized molecules. Silane crosslinking but formed (water crosslinking)
Either of these methods may be used. As described above, according to the sixth aspect of the invention, the heat deformation temperature is increased, and the mechanical strength can be improved.

[0015]

EXAMPLES Specific examples of the halogen-free flame-retardant polyolefin composition according to the present invention will be described below in comparison with comparative examples.

The non-halogen flame-retardant polyolefin composition comprises a combination of a flame-retardant polyolefin containing a metal hydroxide and a flame-retardant silicone rubber containing titanium oxide. Table 1 shows an example of a flame-retardant polyolefin obtained by blending a metal hydroxide with a polyolefin elastomer.

[0017]

[Table 1] Polyolefin elastomer (PE) in Table 1
Has a density of 0.895 g / cm ³ and MI = 1.6 g / cm ³ .
10 min., Specifically, ENGAE 8440 manufactured by Dupont Dow Elastomer Co., Ltd. is used. In addition, Kisuma 5A manufactured by Kyowa Chemical Industry Co., Ltd. is used for magnesium hydroxide.

Table 2 shows examples of the compounding of the flame-retardant silicone rubber obtained by mixing titanium oxide with the silicone rubber.

[0019]

[Table 2] As the silicone rubber in Table 2, KE4603U manufactured by Shin-Etsu Chemical Co., Ltd. is used. ST-01 manufactured by Ishihara Sangyo Co., Ltd. is used for titanium oxide.

Using the flame-retardant polyolefin blending examples (A to F) obtained by blending a metal hydroxide with the polyolefin elastomer shown in Table 1, titanium oxide is blended with the silicone rubber shown in Table 2. Halogen-free flame-retardant polyolefin composition (flame-retardant polyolefin 10) composed by appropriately selecting the compounding examples (ag) of the flame-retardant silicone rubber
Comparative Examples will be described with respect to specific examples in which 50 parts by weight of a flame-retardant silicone rubber is blended with respect to 0 parts by weight.

Example 1 In Example 1, compounding example B of a flame-retardant polyolefin (comprising 80 parts by weight of a metal hydroxide with respect to 100 parts by weight of a polyolefin elastomer) and compounding example f of a flame-retardant silicone rubber ( 6 parts by weight of titanium oxide with respect to 100 parts by weight of silicone rubber).

Example 2 In Example 2, compounding example C of a flame-retardant polyolefin (containing 100 parts by weight of a polyolefin elastomer and 120 parts by weight of a metal hydroxide) and compounding example e of a flame-retardant silicone rubber ( 14 parts by weight of titanium oxide with respect to 100 parts by weight of silicone rubber).

Example 3 In Example 3, a compounding example D of a flame-retardant polyolefin (containing 100 parts by weight of a polyolefin elastomer and 160 parts by weight of a metal hydroxide) and a compounding example d of a flame-retardant silicone rubber ( 12 parts by weight of titanium oxide with respect to 100 parts by weight of silicone rubber).

Example 4 In Example 4, a compounding example D of a flame-retardant polyolefin (containing 100 parts by weight of a metal hydroxide with respect to 100 parts by weight of a polyolefin elastomer) and a compounding example c of a flame-retardant silicone rubber ( (A mixture of 100 parts by weight of silicone rubber and 10 parts by weight of titanium oxide).

Example 5 In Example 5, a blending example E of a flame-retardant polyolefin (a blend of 170 parts by weight of a metal hydroxide with respect to 100 parts by weight of a polyolefin elastomer) and a blending example b of a flame-retardant silicone rubber ( (7 parts by weight of titanium oxide mixed with 100 parts by weight of silicone rubber).

Example 6 In Example 6, a compounding example E of a flame-retardant polyolefin (compounding 170 parts by weight of a metal hydroxide with respect to 100 parts by weight of a polyolefin elastomer) and a compounding example b of a flame-retardant silicone rubber ( 1.0 part by weight of DCP (dicumyl peroxide: a cross-linking agent, specifically, “DCP” manufactured by Ogiya Kogyo Co., Ltd.) is mixed with 100 parts by weight of silicone rubber and 7 parts by weight of titanium oxide. It was done.

Example 7 In Example 7, a blending example B of a flame-retardant polyolefin (a blend of 80 parts by weight of a metal hydroxide with respect to 100 parts by weight of a polyolefin elastomer) and a blending example f of a flame-retardant silicone rubber ( 1.0 part by weight of DCP (dicumyl peroxide: a cross-linking agent, specifically, “DCP” manufactured by Ogiya Kogyo Co., Ltd.) is mixed with 100 parts by weight of silicone rubber and 6 parts by weight of titanium oxide. It was done.

Comparative Example 1 In Comparative Example 2, a compounding example A of a flame-retardant polyolefin (comprising 75 parts by weight of a metal hydroxide with respect to 100 parts by weight of a polyolefin elastomer) and a compounding example g of a flame-retardant silicone rubber ( 16 parts by weight of titanium oxide with respect to 100 parts by weight of silicone rubber).

Comparative Example 2 In Comparative Example 2, a compounding example F of a flame-retardant polyolefin (containing 175 parts by weight of a metal hydroxide with respect to 100 parts by weight of a polyolefin elastomer) and a compounding example a of a flame-retardant silicone rubber ( 6 parts by weight of titanium oxide with respect to 100 parts by weight of silicone rubber).

Examples 1 to 7 and Comparative Examples 1 to
For each of the compositions based on No. 2, a 1.0 mm-thick press sheet was prepared, and the tensile elongation (%) and the tensile strength (MPa) were measured by a tensile test method based on JIS-K7113. Further, a part (length of about 560 mm) was taken from an insulated wire (finished product) in which the conductors were coated with the compositions based on Examples 1 to 7 and Comparative Examples 1 and 2 as conductors, and used as a sample. S61-402 (N
EMA WC5) A vertical combustion test was performed. Table 3 shows the results of the comparison.

[0031]

[Table 3] The wire core in Table 3 indicates that the original valve of the burner is opened with the ignition plug of the tyryl burner ignited, the tip of the blue flame of the burner is applied to the sample for 15 seconds, and then the original valve is closed. The operation of pausing for 4 seconds was repeated four times, and after applying the flame to the sample five times, a judgment of "O" or "No" was made based on whether the sample continued to burn for 1 minute or more.

Each measurement of the tensile elongation and tensile strength in Table 3 is based on a tensile test of JIS-K7113 specified in Japanese Industrial Standards. Fix one end of the sheet (test piece)
The other end is pulled and pulled until the test piece is torn apart, and the length (elongation) at the time of breaking is divided by the length of the original test piece and expressed as a percentage (elongation). That is, the maximum elongation of the test piece when the test piece was stretched was determined. The reference value of the tensile elongation is “350% or more”. Further, the tensile strength (MPa) in Table 3 indicates the load (MPa) at which the sample is pulled when it is pulled, and the load at the time when the sample is pulled, that is, the cross-sectional area ( The maximum tensile load (N) per mm ² ) is shown. Therefore, the mechanical strength can be determined from the magnitude of the tensile strength. The reference value of this tensile strength is “10
MPa or more].

The results of the determination are as follows: “○” when the values exceed the respective reference values of the wire core, the tensile elongation (reference value of 350% or more) and the tensile strength (the reference value of 10 MPa or more). A case where any one of the reference values of the tensile strength was lower than one was designated as “×”. Examples 1 to 7
The judgment results were all “O”, and Comparative Example 1 had a tensile elongation of 5
80%, which is higher than the reference value "350% or more", and the tensile strength is also 13.8MPa, which is higher than the reference value "10MPa or more". Therefore, the judgment result is "x".

In the case of Examples 1 to 5 in which the judgment results were all “O”, the tensile elongation
Are “575%”, Example 2 is “520%”, Example 3 is “489%”, Example 4 is “475%”, and Example 5 is “409%”. But the amount of Mg (OH) ₂ was changed from 80 parts by weight of Example 1 to 120 parts by weight of Example 2,
It can be seen that the value of tensile elongation decreases as the blending amount increases with 160 parts by weight of No. 4 and 170 parts by weight of Example 5. In spite of the same 160 parts by weight of Mg (OH) _{2 in} Examples 3 and 4, the value of tensile elongation was “48”.
9% "(Example 3) and" 475% "(Example 4) are different from Example 3 in the amount of titanium oxide compounded in the flame-retardant silicone rubber kneaded with the flame-retardant polyolefin. The reason is that the amount of Example 4 was as small as 10 parts by weight, whereas the amount was 12 parts by weight.

In the case of Examples 1 to 5 in which the judgment results were all “O”, the tensile strength was found in Example 1
Is “13.2 MPa”, and Example 2 is “12.7 MPa”.
a), Example 3 is “11.7 MPa”, and Example 4 is “1
1.5MPa ”and Example 5 were“ 10.4MPa ”, both of which exceeded the reference value“ 10MPa or more ”.
The compounding amount of (OH) ₂ is from 80 parts by weight of Example 1,
It can be seen that the value of the tensile elongation decreases as the blending amount increases: 120 parts by weight in Example 2, 160 parts by weight in Examples 3 and 4, and 170 parts by weight in Example 5. In spite of the same 160 parts by weight of Mg (OH) _{2 in} Examples 3 and 4, the value of the tensile strength was “11.7 MPa”.
(Example 3) is different from “11.5 MPa” (Example 4) in that the amount of titanium oxide compounded in the flame-retardant silicone rubber kneaded with the flame-retardant polyolefin is 12 wt% in Example 3. Parts, whereas Example 4 was as small as 10 parts by weight.

In Examples 6 and 7, both the crosslinking agents (DC
P), the composition of Example 6 is as follows:
Except for 1.0 part by weight of the crosslinking agent, the composition is the same as that of Example 5, and the composition of Example 7 is the same as that of Example 1 except for 1.0 part by weight of the crosslinking agent. Comparing Example 6 with Example 5, the tensile elongation value of Example 5 was "409".
%, Whereas Example 6 has better characteristics of "444%". As for the value of the tensile strength, Example 5 was “10.4 MPa”, whereas Example 6 was “11.4 MPa”, which is much better. Further, when comparing Example 7 with Example 1, the value of the tensile elongation is "575%" in Example 1, whereas the property of Example 7 is "577%". .
Further, regarding the value of the tensile strength, Example 1 was “13.2”.
MPa, whereas Example 7 is “14.1MPa”.
a "and the characteristics are improved.

When comparing Example 6 with Example 7, Example 6 shows that the compounding amount of Mg (OH) ₂ is 170 parts by weight and the compounding amount of titanium oxide is 7 parts by weight. On the other hand, in Example 7, the compounding amount of Mg (OH) 2 was 80 parts by weight, and the compounding amount of titanium oxide was 15 parts by weight. The value of the tensile elongation of Example 6 is “444%”, whereas the value of the tensile elongation of Example 7 is “577%”.
And Example 7 show much better characteristics. Also,
While the value of the tensile strength of Example 6 is “11.9 MPa”, the value of the tensile strength of Example 7 is “14.1 MPa”.
And Example 7 show much better characteristics. From this, the flame-retardant polyolefin and the flame-retardant silicone rubber to be kneaded with the flame-retardant polyolefin are crosslinked to increase the amount of titanium oxide to be added to the flame-retardant silicone rubber and to be added to the flame-retardant polyolefin. It can be seen that the amount of the metal hydroxide can be reduced.

Comparing Comparative Example 1 with Comparative Example 2, the tensile elongation of Comparative Example 1 was low because the amount of metal hydroxide (magnesium hydroxide) mixed with the flame-retardant polyolefin was as small as 75 parts by weight. Is "580%" and the value of tensile strength is "13.8 MPa", which means that the mechanical properties are good. However, even if 16 parts by weight of titanium oxide is added to the flame-retardant silicone rubber, the required flame retardancy cannot be obtained. In Comparative Example 2, the amount of metal hydroxide (magnesium hydroxide) to be mixed with the flame-retardant polyolefin was as large as 175 parts by weight. Is "9.8MPa"
And the mechanical properties are below the reference values. However, the required flame retardancy is obtained even if the titanium oxide to be blended with the flame-retardant silicone rubber is blended as little as 6 parts by weight. Therefore, both Comparative Examples 1 and 2 do not meet the criteria.

[0039]

Since the present invention is configured as described above, it has the following effects.

According to the first aspect of the present invention, sufficient mechanical properties can be obtained by containing an olefin resin as a main component, containing no halide, suppressing the mixing of metal hydroxide, and obtaining titanium oxide. By kneading the compounded silicone rubber, ICEA S61-402 (NEMA W
It is possible to obtain flame retardant characteristics conforming to the characteristics of the single core vertical flame test of C5).

According to the second aspect of the present invention, the olefin-based resin is a main component, contains no halide, suppresses the compounding of metal hydroxide, obtains sufficient mechanical properties, and obtains titanium oxide. By kneading the compounded silicone rubber, ICEA S61-402 (NEMA W
It is possible to obtain flame retardant characteristics conforming to the characteristics of the single core vertical flame test of C5).

According to the third aspect of the present invention, it is possible to obtain sufficient flame-retardant properties and sufficient mechanical properties as a flame-retardant polyolefin.

According to the fourth aspect of the invention, it is possible to secure the mechanical characteristics of the electric wire / cable.

According to the fifth aspect of the present invention, it is possible to ensure the flame retardancy of the electric wire / cable.

According to the sixth aspect of the invention, the heat deformation temperature is increased, and the mechanical strength can be improved.

Claims (6)

[Claims] 1. A halogen-free flame-retardant polyolefin composition obtained by kneading a silicone rubber containing titanium oxide in addition to a metal hydroxide mixed with an olefin resin. 2. A non-halogen flame-retardant polyolefin composition comprising 100 parts by weight of a flame-retardant polyolefin containing a metal hydroxide and 50 parts by weight of a flame-retardant silicone rubber containing titanium oxide. 3. The flame-retardant polyolefin is prepared by adding metal hydroxide 8 to 100 parts by weight of a polyolefin elastomer.
The halogen-free flame-retardant polyolefin composition according to claim 2, which is produced by kneading 0 to 170 parts by weight with a mixing roll at 120 ° C. 4. The method according to claim 3, wherein the metal hydroxide is one or a mixture of two or more of magnesium hydroxide, aluminum hydroxide, zirconium hydroxide, calcium hydroxide, and barium hydroxide. Non-halogen flame-retardant polyolefin composition. 5. The flame-retardant silicone rubber is produced by kneading 3 to 15 parts by weight of titanium oxide with a mixing roll at 50 ° C. with respect to 100 parts by weight of silicone rubber. A halogen-free flame-retardant polyolefin composition according to the above. 6. The flame-retardant polyolefin and the flame-retardant silicone rubber are cross-linked.
Or a non-halogen flame-retardant polyolefin composition according to item 5.