JP4761536B2 - Polyolefin flame-retardant resin composition and flame-retardant insulated wire - Google Patents

Description

  The present invention relates to a non-halogen polyolefin-based flame-retardant resin composition that has reduced wear resistance and heat resistance, and a flame-retardant insulated wire using the same, and more particularly to a wire harness for automobiles.

  Due to environmental problems and the like, polyolefin resin compositions having non-halogen flame retardancy have been used in place of vinyl chloride resins. However, since a large amount of metal hydroxide is added to obtain high flame retardancy, there has been a problem with respect to weight reduction. For example, since it is necessary to add 70 parts by mass or more with respect to 100 parts by mass of the base resin in order to pass a horizontal combustion test or a 45 degree inclined combustion test for a flame-retardant insulated wire, Specific gravity becomes 1.2 or more and becomes heavier than the polyethylene resin composition which does not use a metal hydroxide. In addition, the specific gravity is close to that of the vinyl chloride resin composition, and there is a problem that it is difficult to perform a separation process by specific gravity. In particular, in a wire harness for an automobile, since the automobile is being digitized, wiring in the automobile is increased, and further reduction in weight and thickness is required. For this reason, wire harnesses for automobiles are particularly problematic in terms of heat resistance, wear resistance, flame retardancy, and the like. In addition, in the case of insulated wires for automobiles coated with a polyvinyl chloride resin composition that has been used in the past, the lead of the additive becomes a problem in the disposal of the waste, and in the disposal of incineration, harmful gases such as chlorine gas and dioxin are present. Substances are an environmental problem. For this reason, a resin composition based on a polyolefin resin has been proposed, but in order to obtain flame retardancy, a large amount of a flame retardant such as metal hydrate is added. I could not.

Various proposals for solving the above problems have been made. For example, Patent Document 1 discloses a flame retardant resin composition containing a propylene-ethylene block copolymer and an ethylene / vinyl acetate copolymer as a polymer component, and a metal hydroxide, and the propylene-ethylene block copolymer in the polymer component The content of the ethylene / vinyl acetate copolymer is 90 to 45% by weight, the content of the ethylene / vinyl acetate copolymer is 10 to 55% by weight, and the metal hydroxide is 30 to 300 parts by weight with respect to 100 parts by weight of the polymer component. A flame retardant and abrasion resistant resin composition is described. However, when the content of the ethylene / vinyl acetate copolymer is increased, the flame-retardant and abrasion-resistant resin composition is poorly compatible with polypropylene, and the mechanical properties are deteriorated. In addition, when the ratio of polypropylene is high, the crystallinity is high due to the characteristics of isotactic polypropylene, and there is a problem of whitening of the coating due to bending. It was not satisfactory. Furthermore, the problem of weight reduction has not been solved. In Patent Document 2, a master batch in which 51 to 500 parts by weight of a metal hydrate is kneaded with 100 parts by weight of an ethylene elastomer and an olefin resin are kneaded, and the olefin resin is mixed in the olefin resin. It is a flame retardant olefin resin composition that is crosslinked in a state where the master batch is micro-dispersed. As the ethylene elastomer, ethylene / propylene / diene copolymer is described, and as the olefin resin, polypropylene, linear low density polyethylene, ultra low density polyethylene, ethylene-α-olefin copolymer, etc. are described. Yes. However, it has been difficult to achieve both flame retardancy and wear resistance in this automobile wire. Further, since a large amount of metal hydrate was added, the problem of weight reduction was not solved, and specific gravity separation from the vinyl chloride resin composition could not be performed.
Japanese Patent No. 3460619 Japanese Patent Laid-Open No. 10-294021

  Therefore, the problem to be solved by the present invention has a non-halogen flame retardant property with a specific gravity of 1.15 or less, and when passed as an insulated wire, it passes the ISO 6722 standard 45 degree inclined fire spread test, An object of the present invention is to provide a polyolefin-based flame retardant resin composition having excellent mechanical properties and abrasion resistance. Another object of the present invention is to provide a polyolefin-based flame retardant resin composition having the above-mentioned characteristics and improved whitening characteristics by bending. Furthermore, it is providing the flame-retardant insulated wire which has the said characteristic and can be classified by specific gravity, especially the wire harness for motor vehicles by using the said polyolefin-type flame-retardant resin composition.

  The problem to be solved is that, as described in claim 1, 50 to 110 parts by mass of melamine cyanurate is added to 100 parts by mass of a base resin comprising 80 to 95% by mass of polypropylene and 5 to 20% by mass of polyethylene. The problem is solved by using a polyolefin-based flame retardant resin composition having a specific gravity of 1.15 or less.

  In addition, as described in claim 2, a propylene-α-olefin copolymer and / or atactic having a surface hardness of 60 to 95% measured by ASTM D2240 in 80 to 95% by mass of polypropylene. The problem can be solved by using a polyolefin-based flame retardant resin composition according to claim 1, which is polypropylene and has a specific gravity of 1.15 or less.

  Furthermore, as described in claim 3, the polypropylene is solved by making the polyolefin flame-retardant resin composition according to claim 1 or 2 having a melting point of 160 ° C or higher.

  Moreover, as described in Claim 4, the said polyethylene is a low density polyethylene or a linear low density polyethylene, The polyolefin-type flame retardant resin composition in any one of Claims 1-3.

  Furthermore, the flame-retardant insulated wire by which the polyolefin flame-retardant resin composition in any one of Claims 1-4 described in Claim 5 was coat | covered on the conductor. Moreover, it is solved by setting it as the wire harness for motor vehicles assembled using the flame-retardant insulated wire of Claim 5 described in Claim 6.

  The present invention as described above has a specific gravity of 1.15 or less, in which 50 to 110 parts by mass of melamine cyanurate is added to 100 parts by mass of base resin composed of 80 to 95% by mass of polypropylene and 5 to 20% by mass of polyethylene. Because it is a polyolefin-based flame retardant resin composition, it has light weight and non-halogen flame retardant properties, and when used for an insulated wire, it passes the ISO 6722 standard 45-degree inclined flame spread test, as well as mechanical properties and abrasion resistance. It is possible to provide a polyolefin-based flame retardant resin composition having excellent wear resistance.

  Further, in the 80 to 95% by mass of polypropylene, 5 to 30% by mass is a propylene-α-olefin copolymer and / or atactic polypropylene having a surface hardness of 60 or less as measured by ASTM D2240, and a specific gravity of 1.15. Since it is the following polyolefin-type flame-retardant resin composition, it has the above-mentioned properties, and the whitening resistance property by bending is improved, and the flexibility can be improved when used for a flame-retardant insulated wire.

  By using a polypropylene having a melting point of 160 ° C. or more, it is possible to obtain the heat resistance grades of class 1 and class 2 of the ISO 6722 standard while having the above characteristics. Further, by using low density polyethylene or linear low density polyethylene as the polyethylene, the low temperature embrittlement characteristics are improved in addition to the above characteristics.

    Furthermore, the polyolefin-based flame retardant resin composition has a non-halogen flame retardant having a specific gravity of 1.15 or less, by using a flame retardant insulated wire coated on a conductor. It passes the standard 45-degree inclined fire spread test and has excellent resistance to whitening by bending, as well as excellent mechanical properties and wear resistance. Furthermore, it can be a flame retardant insulated wire that can be separated from the vinyl chloride resin-coated insulated wire by specific gravity. Moreover, it is useful as a wire harness which has the said characteristic and was reduced in weight by setting it as the automotive wire harness assembled using the said flame-retardant insulated wire.

  The present invention is described in detail below. The invention described in claim 1 has a specific gravity of 1.15 or less, in which 50 to 110 parts by mass of melamine cyanurate is added to 100 parts by mass of base resin comprising 80 to 95% by mass of polypropylene and 5 to 20% by mass of polyethylene. This is a polyolefin-based flame retardant resin composition.

  First, polypropylene (hereinafter referred to as PP) constituting the base resin will be described. PP used in the present invention includes not only a PP homopolymer but also a random copolymer or block copolymer with ethylene. In addition, a block copolymer with ethylene is preferable because of wear resistance. Furthermore, they can also be used as a mixture. Specific examples of PP include B701WB, which is a block copolymer of Prime Polymer Co., Ltd. And this PP is added in the ratio of 80-95 mass% in base resin. This is because the wear resistance is insufficient if the blending amount is not within this range. This is because the abrasion resistance is improved by dispersing a certain amount of polyethylene (hereinafter referred to as PE) in PP. Further, as described in claim 3, the PP preferably has a melting point of 160 ° C. or higher. This is because by using such PP, it can be used as a heat resistance grade of class 1 and class 2 defined in the ISO 6722 standard.

  Further, as described in claim 2, the PP is a propylene-α-olefin copolymer having a surface hardness of 60 or less as measured by ASTM D2240 in 80 to 95% by mass of PP. By using atactic polypropylene, the flexibility of the obtained polyolefin-based flame-retardant resin composition can be improved, and workability and the like can be improved when used for a flame-retardant insulated wire. Thus, 5 to 30% by mass is replaced with a propylene-α-olefin copolymer and / or atactic polypropylene having a surface hardness measured by ASTM D2240 of 60 or less, so the PP addition amount range is 50 to 90% by mass. It becomes the range. The reason why the surface hardness of the propylene-α-olefin copolymer and / or atactic polypropylene is set to 60 or less is to prevent whitening due to bending by mixing materials having low crystallinity. If the addition amount exceeds 30% by mass, the wear resistance is lowered, which is not preferable. Examples of the propylene-α-olefin copolymer having a surface hardness measured by ASTM D2240 of 60 or less include Tuffmer XM-5070 manufactured by Mitsui Chemicals, and T3527 manufactured by Sumitomo Chemical Co., Ltd. as atactic polypropylene.

  Moreover, various PE can be used for PE which comprises base resin with PP. For example, high density polyethylene (hereinafter referred to as HDPE), medium density polyethylene (hereinafter referred to as MDPE), low density polyethylene (hereinafter referred to as LDPE), and linear low density polyethylene (hereinafter referred to as LLDPE). Among these, as described in claim 4, it is preferable to use LDPE or LLDPE. This is to improve flexibility, low temperature embrittlement characteristics and resistance to whitening by bending. And the ratio is added in the ratio of 5-20 mass% in base resin. This is because if the blending amount is less than 5% by mass, there is no effect of improving the abrasion resistance, and if it exceeds 20% by mass, the abrasion resistance is lowered. The polyolefin mixture blended in such a ratio can be used as a base resin, and a polyolefin flame-retardant resin composition can be obtained by blending various parts of the various additives with respect to 100 parts by mass. .

  Then, by blending 50 to 110 parts by weight of melamine cyanurate with respect to 100 parts by weight of the base resin, a non-halogen polyolefin flame retardant resin composition having a specific gravity of 1.15 or less and reduced in weight is obtained. be able to. Melamine cyanurate is generally used as a flame retardant for polyamide and polyurethane, but decomposes and releases a large amount of nitrogen gas, etc., so it can be used as a flame retardant for resins, and its specific gravity is Since it is small, a polyolefin-type flame retardant resin composition can be reduced in weight. Moreover, the flame-retardant insulated wire manufactured by coat | covering the said flame-retardant resin composition on a conductor can obtain the flame retardance which passes the 45 degree inclination combustion test in ISO6722. And this polyolefin-type flame-retardant resin composition is a flame-retardant resin composition which was excellent also in mechanical characteristics, such as breaking strength and breaking elongation, and abrasion resistance. If the amount added is less than 50 parts by mass, flame retardancy that passes the ISO 45 degree gradient combustion test cannot be obtained. If the amount added exceeds 110 parts by mass, the mechanical properties are lowered and the specific gravity is 1. It becomes 15 or more, and specific gravity separation becomes impossible. The polyolefin-based flame-retardant resin composition of the present invention thus obtained has the above-mentioned properties by coating on a conductor, and is also a flame-retardant insulated wire that can be separated by specific gravity, particularly for automobiles. It is useful as a wire harness.

  The polyolefin-based flame retardant resin composition is obtained by melt-kneading a predetermined amount of each base resin and melamine cyanurate with a commonly used kneader such as a twin-screw kneading extruder, a Banbury mixer, a kneader, or a roll. . In addition, other additives such as an antioxidant, an anti-aging agent, a processing aid, a color pigment, carbon black, and the like are produced by appropriately blending within the range not impairing the object of the present invention as necessary. be able to.

  The polyolefin-based flame-retardant resin composition is extrusion-coated on a conductor as described in claim 5 and used as a flame-retardant insulated wire for various applications. That is, the flame-retardant insulated wire is a non-halogen flame retardant insulating layer that passes the ISO 6722 45 degree inclined combustion test and has a reduced specific gravity of 1.15 or less. This makes it possible to separate the vinyl chloride resin composition and the like by specific gravity. It also has excellent wear resistance and mechanical properties. Specifically, the mechanical properties are those having a breaking strength of 10 MPa or more and a breaking elongation of 150% or more. In addition, the wear resistance can withstand 30 times or more at a needle diameter of 0.45 mm and a load of 7 N in accordance with the scrape test of JASO D611.

And as described in Claim 6, when it is set as the wire harness (assembled electric wire) for motor vehicles especially, it is useful from the characteristic. In particular, when electron beam irradiation crosslinking is performed, it is preferable as a wire harness for automobiles with a thin coating. As the wire harness, an insulated electric wire is generally used in which a coating layer is applied to a thickness of about 0.1 to 0.4 mm by extrusion coating on a copper conductor of about 0.5 to ² mm ² . The polyolefin-based flame retardant resin composition of the present invention is non-halogen and flame retardant, has a reduced specific gravity of 1.15 or less, and is excellent in wear resistance and mechanical properties. Because it is a thing, it is most suitable as a wire harness. In particular, when crosslinked by electron beam irradiation, the coating can be thinned, which can contribute to further weight reduction. In addition, when a crosslinking aid such as trimethylolpropane trimethacrylate or triallyl isocyanurate is added, a crosslinking network is efficiently constructed by electron beam irradiation.

  A flame-retardant insulated wire was prepared using the polyolefin-based flame-retardant resin composition described in Table 1 or Table 2, and the effect of the present invention was confirmed. Specifically, it is a flame-retardant insulated electric wire having an outer diameter of 1.04 mm, in which a coating layer having a thickness of 0.25 mm is formed on a stranded conductor (19 strands of 0.12 mm copper wire). The constituent materials of the polyolefin-based flame retardant resin composition are B701WB (prime polymer block copolymer) as PP, C150 (Ube LDPE) as PE, and Toughmer XM-5070 (propylene-α-olefin copolymer). Mitsui Chemicals Co., Ltd.), atactic polypropylene, T3527, etc. (Sumitomo Chemical Co., Ltd.), melamine cyanurate, MC860 (Nissan Chemical Co., Ltd.), and Ciba Specialty Chemicals Irganox MD1024 and Irganox 1010 as antioxidants It was.

  The following test was done about the said flame-retardant insulated wire. Based on JIS standard C3005, tensile breaking strength (tensile speed 200 mm / min, marked line 20 mm) and tensile breaking elongation (tensile speed 200 mm / min, marked line 20 mm) were measured. An elongation of 150% or more was accepted, and the others were regarded as unacceptable. Moreover, the 45 degree inclination combustion test of ISO standard 6722 was done about the flame retardance. The digestion was made within 70 seconds after the end of the combustion, and the case where at least 50 mm length remained in the 500 mm length sample was judged as acceptable, otherwise it was regarded as unacceptable. Furthermore, the scrape test of the low voltage | pressure electric wire for motor vehicles was done based on JASO D611. At a needle diameter of Φ0.45 mm and a load of 7 N, 30 times or more passed, and less than 30 times failed. (In order to eliminate the influence of the knitted meat, it was rotated 12 times by 90 ° and performed 12 times, and the average value was examined.) In order to examine the whitening characteristics by bending, 6 turns were wound around 6 mm, 3 mm and 1 mm diameter mandrels. The occurrence of whitening was observed. If there was no whitening in a Φ6 mm mandrel, it was considered acceptable. Table 1 shows the results of the examples, and Table 2 shows the results of the comparative examples.

  As is clear from Table 1, the flame-retardant insulated wires of the present invention described in Examples 1 to 21 are excellent in passing all test items. That is, the tensile breaking strength is 10 MPa or more, the tensile breaking elongation is 150% or more, the flame retardancy is passed the 45 degree inclined combustion test of ISO standard 6722, and more than 30 times are cleared in the scrape test. . In particular, the polyolefin-based flame retardant resin composition mixed with the PP copolymer shown in Examples 10 to 21 has excellent whitening characteristics by bending. This will be described in detail. As described in Examples 1 to 3, when the addition amount of melamine cyanurate is 50 parts by mass, the PP addition amount is 80 to 95% by mass, and the PE addition amount is 20 to 5% by mass. Even when the addition amount of melamine cyanurate is 80 parts by mass as in Examples 4 to 6, the addition amount of PP is in the range of 80 to 95% by mass, the addition amount of PE is 20 to 5% by mass, and Comparative Examples 7 to 9 As shown above, even when the addition amount of melamine cyanurate is 110 parts by mass, the PP addition amount is 80 to 95% by mass and the addition amount of PE is 20 to 5% by mass. I understand. However, as for the whitening property by bending, whitening was observed when a mandrel having a diameter of 3 mm was used. Further, as in Examples 10 to 12, when the PP addition amount is 50% by mass and the PE addition amount is 20% by mass, and the addition amount of the PP copolymer and / or atactic PP is 30 parts by mass, It turns out that all test items pass. Further, the whitening property by bending was not observed even when a mandrel having a diameter of 1 mm was used. Furthermore, as in Examples 13 to 15, when the addition amount of PP is 70% by mass and the addition amount of PE is 10% by mass, the addition amount of PP copolymer and / or atactic PP is 20 parts by mass. It turns out that it passes the test item. Further, the whitening property by bending was not observed even when a mandrel having a diameter of 1 mm was used.

  Also, as in Examples 16 and 17, all test items were obtained when the PP addition amount was 90% by mass, the PE addition amount was 5% by mass, and the PP copolymer or atactic PP addition amount was 5 parts by mass. It turns out to pass. Further, the whitening property by bending was not observed even when a mandrel having a diameter of 3 mm was used. Also, as in Examples 18 and 19, all tests were conducted when the PP addition amount was 80% by mass, the PE addition amount was 20% by mass, and the PP copolymer or atactic PP addition amount was 5 parts by mass. It turns out that the item passes. Moreover, the whitening characteristic by bending was not seen even if it used the mandrel of (PHI) 3mm. Further, as in Example 20, when the PP addition amount was 75 mass%, the PE addition amount was 10 mass%, the PP copolymer addition amount and the atactic PP addition amount were 5 mass parts, all tests It turns out that the item passes. Moreover, the whitening characteristic by bending was not seen even if it used the mandrel of (PHI) 3mm. Furthermore, as in Example 21, when the addition amount of PP is 90% by mass, the addition amount of PE is 5% by mass, and the addition amount of PP copolymer is 5 parts by mass, all the test items can be passed. I understand. Moreover, the whitening characteristic by bending was not seen even if it used the mandrel of (PHI) 3mm.

  On the other hand, as for the example which deviates from this invention described in Comparative Examples 1-10, either the tensile breaking strength, the tensile breaking elongation, the flame retardance, the scrape test, or whitening by bending failed. That is, when the PP amount is as low as 75% by mass as in Comparative Example 1 and the PE amount is as large as 25% by mass, the elongation at break fails, and when the base resin is only PP as in Comparative Example 2, the elongation at break is low. The scrape test failed, and the whitening due to bending also failed. Further, as in Comparative Example 3, when the melamine cyanurate is as small as 40 parts by mass, the flame retardancy is rejected, and when the melamine cyanurate is increased as 120 parts by mass as in Comparative Example 4, the elongation at break and the scrape test are considered. Fail. As in Comparative Examples 5 and 6, even when the addition amount of PP and PE is within the range of the present invention, when the addition amount of PP copolymer or atactic PP is as large as 40 parts by mass, both are subjected to a scrape test. Is rejected. Further, as in Comparative Example 7, even when the addition amount of PP and PE is within the range of the present invention, when the total addition amount of PP copolymer and atactic PP is as large as 40 parts by mass, the scrape test was rejected. Become. Further, as in Comparative Examples 8 and 9, when the addition amount of PP is as small as 40% by mass and the addition amount of PP copolymer or atactic PP is as large as 40% by mass, both fail the scrape test. . Further, as in Comparative Example 10, when the PP addition amount was as small as 40% by mass and the total addition amount of the PP copolymer and atactic PP was as large as 40 parts by mass, the scrape test was also rejected.

  The wire harness for automobiles of the present invention as described above is a non-halogen flame retardant and specific gravity reduced to 1.15 or less, as well as excellent wear resistance, heat resistance and whitening resistance by bending. Therefore, it can be sufficiently used as a high-density wire harness for automobiles and is useful.

Claims (6)

  Polyolefin difficulty characterized by adding 50 to 110 parts by mass of melamine cyanurate to 100 parts by mass of base resin comprising 80 to 95% by mass of polypropylene and 5 to 20% by mass of polyethylene, and having a specific gravity of 1.15 or less. A flammable resin composition.   Among the 80 to 95% by mass of polypropylene, 5 to 30% by mass is a propylene-α-olefin copolymer and / or atactic polypropylene having a surface hardness measured by ASTM D2240 of 60 or less, with a specific gravity of 1.15 or less. The polyolefin-based flame retardant resin composition according to claim 1, wherein   The polyolefin-based flame retardant resin composition according to claim 1, wherein the polypropylene has a melting point of 160 ° C. or higher.   The polyolefin-based flame retardant resin composition according to claim 1, wherein the polyethylene is low-density polyethylene or linear low-density polyethylene.   A flame-retardant insulated wire, wherein the polyolefin-based flame-retardant resin composition according to any one of claims 1 to 4 is coated on a conductor.   An automotive wire harness assembled using the flame-retardant insulated wire according to claim 5.