JP5146718B2 - Non-halogen flame retardant wire and non-halogen flame retardant cable - Google Patents

Description

  The present invention relates to a halogen-free flame retardant wire and a halogen-free flame retardant cable, and particularly to a halogen-free flame retardant wire and a halogen-free flame retardant cable excellent in oil resistance and flame resistance.

  Electric wires and cables are required to have flame resistance and oil resistance. For this reason, a crosslinked chloroprene rubber has been used for the insulator covered by these. This is because the crosslinked chloroprene rubber contains highly polar chlorine in its composition and is excellent in oil resistance, particularly mineral oil resistance. In addition, the crosslinked chloroprene rubber is excellent in flame retardancy because it releases chlorine during combustion and suppresses combustion of the insulator. Therefore, the crosslinked chloroprene rubber has been used as an oil resistant and flame retardant rubber.

  In recent years, with increasing interest in the environment, there has been a demand for electric wires and cables coated with an insulator made of non-halogen that does not release harmful halogen gas into the atmosphere during combustion. However, since the crosslinked chloroprene rubber is crosslinked and further contains chlorine, it cannot be used as a non-halogen material or a recycled material.

  Therefore, in order to provide non-halogen and recyclability, an insulator made of a non-halogen thermoplastic elastomer has begun to be used as an insulator to be covered with an electric wire or cable. Non-halogen thermoplastic elastomers differ from crosslinked chloroprene rubber in that they can withstand high-temperature use without the need for a crosslinking process, and because they do not require a crosslinking process, they are inexpensive and highly recyclable. It is because it can supply.

  In addition, in the related art, there is one in which an olefin-based composition using a reactor blend type is excellent in flexibility (for example, Patent Document 1). In addition, there is one that is applied to an electric wire insulator excellent in the balance of flexibility, scratch resistance, and tensile elongation characteristics (for example, Patent Document 2). Moreover, there exists what applied the thermoplastic olefin type composition to the insulator of the electric wire excellent in heat resistance and tensile strength (for example, patent document 3).

JP-A-6-25367 JP 2006-241225 A JP 2006-505665 A

  However, conventional non-halogen thermoplastic elastomers are greatly affected by a decrease in oil resistance due to non-crosslinking and a decrease in flame resistance due to non-halogenation, and it has been difficult to achieve both oil resistance and flame resistance. For this reason, in order to obtain a thermoplastic elastomer excellent in oil resistance and flame retardancy, blending with a polymer excellent in oil resistance and combined use with a flame retardant are performed. A halogen-free thermoplastic elastomer that sufficiently satisfies the properties has not yet been obtained.

  An object of the present invention is to provide a halogen-free flame retardant electric wire and a halogen-free flame retardant cable having excellent oil resistance and flame resistance.

A first aspect of the present invention is a non-halogen flame retardant electric wire in which an outer periphery of a metal conductor is coated with an insulator, wherein the insulator includes 51 to 85 mol% of crystalline polypropylene in monomer units. It is characterized by containing 40 to 300 parts by mass of a metal hydroxide with respect to 100 parts by mass of a blend of a polyolefin resin and more than 50 parts by mass and less than 100 parts by mass .

According to a second aspect of the present invention, in the invention according to the first aspect, the blend includes 5 to 40 parts by mass of the polyolefin with respect to 60 to 95 parts by mass of the reactor blend type polyolefin-based thermoplastic resin. It is characterized by that.

  According to a third aspect of the present invention, in the invention according to the first or second aspect, the polyolefin contains at least one of a crystalline resin and a polar rubber.

According to a fourth aspect of the present invention, there is provided a non-halogen flame retardant cable in which an insulator is coated on the outer periphery of a metal conductor, wherein the insulator includes 51 to 85 mol% of crystalline polypropylene in monomer units. It is characterized by containing 40 to 300 parts by mass of a metal hydroxide with respect to 100 parts by mass of a blend of a polyolefin resin and more than 50 parts by mass and less than 100 parts by mass .

According to a fifth aspect of the present invention, in the invention described in the fourth aspect, the blend includes 5 to 40 parts by mass of the polyolefin with respect to 60 to 95 parts by mass of the reactor blend type polyolefin-based thermoplastic resin. It is characterized by that.

  According to a sixth aspect of the present invention, in the invention according to the fourth or fifth aspect, the polyolefin contains at least one of a crystalline resin and a polar rubber.

  According to the present invention, a non-halogen flame-retardant electric wire and a non-halogen flame-retardant cable that are non-halogen and have excellent oil resistance and flame resistance can be obtained.

In order to obtain a non-halogen flame retardant electric wire and a non-halogen flame retardant cable that achieve both oil resistance and flame retardancy, the inventors have a thermoplastic elastomer coated on a metal conductor as an insulator with excellent oil resistance and flexibility. I thought it was necessary. As a result of various studies, it has been found that a desired thermoplastic elastomer can be obtained by using a reactor blend type polyolefin-based thermoplastic resin as a base. The reactor blend type polyolefin-based thermoplastic resin regulates the content of propylene, which is a crystalline polyolefin excellent in heat resistance and oil resistance, within a certain range, and the polyolefin and metal hydride are distributed in a predetermined composition distribution. It has been found that a halogen-free flame retardant electric wire and flame retardant cable having excellent oil resistance and flame retardancy can be obtained by addition.
Based on this knowledge, the best mode for carrying out the present invention will be described below. However, this embodiment is shown as an example, and various modifications can be made without departing from the technical idea of the present invention. It is.

FIG. 1 shows a cross-sectional structure of an embodiment of a halogen-free flame retardant wire and a halogen-free flame retardant cable.
As shown in FIG. 1, the non-halogen flame retardant electric wire / cable is one in which the outer periphery of a long metal conductor 1 having a round cross section is covered with an insulating layer 2 of an insulator. The cross-sectional shape of the non-halogen flame retardant wire and the non-halogen flame retardant cable is not limited to a round shape, and an insulating layer is provided on a rectangular metal conductor obtained by slitting from a plate-like copper plate or rolling a round wire. It may be coated.
In addition, the flame retardant electric wire / cable is only required to have a metal conductor covered with an insulator. In another embodiment, the outer periphery of the metal conductor 1 is covered with an insulating layer 2 and the outer periphery thereof is covered with a sheath layer 3. As shown in FIG. 3, a structure having a covering structure, or a structure in which a plurality of metal conductors 1 covered with an insulating layer 2 are twisted together and the outer periphery thereof is covered with a sheath layer 3 is exemplified.

  An example of the metal of the metal conductor 1 is copper. As the metal conductor 1, for example, a copper wire may be used as a single wire, or may be used as a plurality of stranded wires or knitted wires, and the copper wire may be subjected to hot dipping or tin plating by electrolysis.

  Examples of the material of the sheath layer 3 include a reactor blend type polyolefin-based thermoplastic elastomer.

The insulating material of the insulating layer 2 includes a reactor blend type polyolefin-based thermoplastic resin containing 51 to 85 mol% of crystalline polypropylene in monomer units, and a blend of polyolefin with more than 50 parts by weight and less than 100 parts by weight . On the other hand, the thing containing 40-300 mass parts of metal hydroxides is used. The reactor blend type polyolefin-based thermoplastic resin contains, for example, mainly an α-olefin polymer in addition to the crystalline polypropylene.

The reactor blend type polyolefin-based thermoplastic resin is a product produced by a multistage polymerization method. In this polymerization method, the resin component produced by the polymerization at each stage is blended in a reactor at the time of polymerization. Therefore, amorphous polyolefin can be finely dispersed in, for example, crystalline polyolefin as compared with a simple blending method using a closed kneader such as a kneader or a Banbury mixer or a roll.
In particular, by setting the composition ratio of crystalline polypropylene within the range of 51 to 85 mol% in monomer units, the resulting reactor blend type thermoplastic elastomer is finely dispersed so that the component that becomes the dispersed phase is about 1 μm or less in diameter. And can have an interpenetrating network structure without a clear sea-island structure. Accordingly, the advantages of polyolefins having different properties can be achieved, and a base material excellent in oil resistance and flexibility can be obtained.

  The composition ratio of the crystalline polypropylene of the thermoplastic elastomer is defined as 51 to 85 mol% in monomer units, and if it exceeds 85 mol%, the flexural modulus serving as an index of flexibility exceeds 20 MPa, This is because the flame-retardant electric wire / cable having the insulating layer 2 cannot provide the same flexibility as soft PVC. If it is less than 51 mol%, the oil resistance cannot be satisfied.

Moreover, there needs to be a reactor blend type polyolefin-based thermoplastic resin 50 parts by weight than less than 100 parts by weight of a polyolefin 0 parts by mass than 50 parts by mass or less of the blend 100 parts by weight. If it is not in this range, the non-halogen flame retardant electric wire cannot satisfy the oil resistance.

Furthermore, flame retardance and oil resistance can be improved by blending polyolefin with a reactor blend type polyolefin-based thermoplastic resin. The blend ratio is preferably 5 to 40 parts by mass of polyolefin with respect to 60 to 95 parts by mass of the reactor blend type polyolefin-based thermoplastic resin.
Become hard when selecting a polyolefin crystalline resins, since the flexibility is impaired when the wire cable, polyolefin 10 to 40 parts by weight with respect to 60 to 90 parts by weight reactor blend type polyolefin-based thermoplastic resin Are preferably blended together.
Moreover, when selecting polar rubber for polyolefin, it is more preferable that it is 10-50 mass parts of polyolefin with respect to 50-90 mass parts of reactor blend type | mold polyolefin-type mature plastic resins.

By making 40 to 300 parts by mass of a metal hydroxide flame retardant into 100 parts by mass of a blend of the reactor blend type polyolefin-based thermoplastic resin and polyolefin, the flame retardancy when an electric wire / cable is obtained is imparted. be able to. The low flame heat less than 40 parts by mass, flexibility and mechanical strength is lowered it exceeds 300 parts by mass. As for content of the flame retardant which consists of metal hydroxides, 50-200 mass parts is more preferable.
Furthermore, the metal hydroxide used as a flame retardant can prevent aggregation when dispersed in the resin by performing silane treatment on the surface, and can improve the adhesion by increasing the adhesion with the resin.

As the polyolefin blended with the reactor blend type polyolefin-based thermoplastic resin, the oil resistance can be further improved by selecting at least one of a crystalline resin and a polar rubber. Here, examples of the crystalline resin include polyethylene and polypropylene. However, the crystalline resin is not particularly limited as long as it is a polyolefin and has a melting point. Similarly, examples of the polar rubber include acrylonitrile butadiene rubber and urethane rubber. However, the polar rubber is not particularly limited as long as it has a polar group in the molecule and is excellent in oil resistance.
When polyolefin is selected from polar rubbers, the difference in viscosity between the reactor blend type polyolefin thermoplastic resin and polyolefin is large. Dispersion is poor with simple blends, making it difficult to obtain the desired properties. From the standpoint of properties, a rubber-crosslinked dispersion using a type cross-linking machine is preferred.
Moreover, you may add antioxidant, a coloring agent, a filler, a lubricant, etc. to the said resin composition suitably as needed.

  The flame-retardant electric wire and flame-retardant cable of the above embodiment can be produced by, for example, using a normal extrusion molding line, melt-kneading the resin composition, and extruding the resin composition onto a single or plural metal conductors. . For melt kneading, for example, a batch kneader or a twin screw extruder is used. Moreover, for example, a twin screw extruder is used for the extrusion line. With this twin-screw extruder, the melt-kneaded resin composition is extruded, and the metal conductor is coated with this resin composition to form a coating layer.

  The non-halogen flame retardant electric wire and the flame retardant cable are suitable for, for example, an aviation lighting electric wire and cable.

Examples will be described below.
FIG. 4 shows the results of an evaluation test of the composition of the insulator (resin composition) in the example and various characteristics, and FIG. 5 shows the composition of the insulator (resin composition) in the comparative example and the evaluation of various characteristics. The result of a test is shown.
The sample used for the evaluation test was prepared by extruding a resin composition having the composition of the example shown in FIG. 4 and a resin composition having the composition of the comparative example shown in FIG. 5 into a sheet shape having a thickness of 2 mm. These samples were subjected to initial tensile strength and tensile elongation tests, heat resistance tests, and oil resistance tests.
Moreover, the flame-retardant electric wire used for the evaluation test of flame retardancy and wiring property is the structure shown in FIG. 1, and the metal conductor 1 having a conductor outer diameter of 3.6 mm with seven twisted copper wires is used in FIG. And the resin composition shown in FIG. 5 was coat | covered by extrusion molding, and the coating layer 2 whose outer diameter is 12 mm was formed. A wiring test was performed using this flame-retardant electric wire.

Abbreviations and their contents in the compositions of FIGS. 4 and 5 are as follows.
TPO: polyolefin-based thermoplastic resin reactor type TPO-A (density: 0.87 g / cm ³ , MI: 7 g / 10 min, crystalline polypropylene unit: 51 mol%)
Reactor type TPO-B ^{(Density: 0.87g / cm 3, MI:} 7g / 10min, crystalline poly propylene unit: 63 mol%)
Reactor type TPO-C ^{(Density: 0.89g / cm 3, MI:} 7g / 10min, crystalline poly propylene unit: 45 mol%)
Reactor type TPO-D ^{(Density: 0.89g / cm 3, MI:} 7g / 10min, crystalline poly propylene unit: 90 mol%)
Linear low density polyethylene (Density: 0.92 g / cm ³ , MI: 2 g / 10 min)
Random type polypropylene (density: 0.90 g / cm ³ , MI: 11 g / 10 min)
Acrylonitrile butadiene rubber (Amount of bound acrylonitrile: 32%)
Flame retardant (magnesium hydroxide, average particle size: 1.0 μm)
Antioxidant (phenolic anti-aging agent)
Lubricant (fatty acid amide)

Moreover, the evaluation test of FIG.4 and FIG.5 was measured with the following method.
(1) Initial tensile strength and tensile elongation test Using a sheet-like sample having a thickness of 2 mm in accordance with JIS C-3005, a tensile strength test was conducted at a speed of 500 mm / min. The initial tensile strength was set to 13 MPa or more, and the tensile elongation was set to 300% or more.
The tensile elongation is calculated by the following formula (a).
(A) Tensile elongation (%) = [(sample length after tensile test) − (sample length before tensile test)] × 100 / (sample length before tensile test)

(2) Heat resistance test After the sample used for the initial tensile test was exposed to a thermostat in accordance with JIS C-3005 at 100 ° C for 96 hours, a tensile test was performed on the cooled sample. The tensile strength residual rate and the tensile elongation residual rate were measured. The tensile strength residual ratio and the tensile elongation residual ratio were set to 60% or more as target values.
The tensile strength residual rate and the tensile elongation residual rate are calculated by the following formulas (b) and (c).
(B) Tensile strength residual ratio (%) = (Tensile strength after test) × 100 / (Tensile strength before test)
(C) Tensile elongation residual ratio (%) = (tensile elongation after test) × 100 / (tensile elongation before test)

(3) Oil resistance test The sample used in the initial tensile test was immersed in IRM-902 test oil heated to 120 ° C for 4 hours in accordance with JIS C-3005, and then the oil was wiped off at room temperature. A tensile test was performed on the sample cooled for 4 hours, and the residual tensile strength and residual tensile elongation were measured. The tensile strength residual ratio and tensile elongation residual ratio were set to 80% or more as target values.

(4) Flame Retardancy Test The flame retardant electric wire (about 300 mm in length) described above was tilted 60 degrees from the horizontal plane in accordance with JIS C-3005, and the upper and lower ends of the electric wire were gripped. And the tip of the burner internal flame was applied to the position of about 20 mm from the lower end of the electric wire until it burned within 30 seconds, and after removing the burner, the degree of combustion was visually confirmed. Here, the burner flame was an inner flame of 35 mm and an outer flame of 130 mm. A sample that self-extinguished within 60 seconds without burning continued after removing the burner was evaluated as “pass”, and a sample that continued burning for 60 seconds or longer was determined as “failed”.

(5) Wiring property (flexibility) test The above-mentioned flame-retardant electric wire is pushed into a gas pipe bent at 90 degrees, and the passage of the electric wire is compared with that of a soft PVC-coated flame-retardant electric wire. If it is equal to or greater than the flame retardant wire, “○ (passed)”, otherwise “× (failed)”.

(Examples 1-9)
As shown in FIG. 4, the composition in Example 1-9, with respect to 100 parts by weight of olefin polymer, 1 part by weight and the lubricant 1 part by weight antioxidant is added.
In Examples 1 to 9, a reactor type polyolefin thermoplastic resin containing 51 to 85 mol% of crystalline polypropylene as a monomer unit is used. For example, in Example 1, the reactor type TPO-A has a composition of 80 parts by mass , random type polypropylene 20 parts by mass , and flame retardant 40 parts by mass .

(Comparative Examples 1-6)
As shown in FIG. 5, the compositions in Comparative Examples 1 to 6 are also added with 1 part by mass of an antioxidant and 1 part by mass of a lubricant with respect to 100 parts by mass of the olefin polymer.

In Examples 1 to 9, the target values were all achieved in the evaluation of the heat resistance and oil resistance test results. Moreover, in the evaluation of the flame retardancy test result, it was “pass”, and in the wiring property, it was “◯”.
However, Comparative Examples 1 to 6 could not satisfy the target characteristics.
In Comparative Examples 1 and 2, in 100 parts by mass of the blend, the reactor type polyolefin thermoplastic resin is 50 parts by mass and 100 parts by mass , and the residual tensile strength in oil resistance is less than 80%, which does not satisfy the oil resistance. It was.
As in Comparative Example 3, the reactor type TPO containing less than 51 mol% of crystalline polypropylene had a residual tensile strength of less than 80% and did not satisfy the oil resistance.
As in Comparative Example 4, the reactor type TPO containing 85% by mole of crystalline polypropylene could not satisfy the flame retardancy and the wiring property.
In Comparative Example 5, the flame retardant was not in the range of 40 to 300 parts by mass , and the flame retardancy could not be satisfied.
In Comparative Example 6, a reactor type polyolefin thermoplastic resin that does not contain crystalline polypropylene in a monomer unit range of 51 to 85 mol% is used, and the flame retardant is not in the range of 40 to 300 parts by mass. I was not satisfied.

It is sectional drawing of the flame-retardant electric wire and flame-retardant cable of one Embodiment of this invention. It is sectional drawing of the flame-retardant electric wire and flame-retardant cable of other embodiment of this invention. It is sectional drawing of the flame-retardant electric wire and flame-retardant cable of other embodiment of this invention. It is a figure which shows the composition of the insulator in an Example, and the result of a characteristic evaluation test. It is a figure which shows the composition of the insulator in a comparative example, and the result of a characteristic evaluation test.

Explanation of symbols

1 Metal conductor 2 Insulating layer 3 Sheath layer

Claims (6)

In a non-halogen flame retardant electric wire whose outer periphery is coated with an insulator on a metal conductor, the insulator is more than 50 parts by mass of a reactor blend type polyolefin-based thermoplastic resin containing 51 to 85 mol% of crystalline polypropylene in monomer units, and 100 parts by mass. A non-halogen flame-retardant electric wire comprising 40 to 300 parts by mass of a metal hydroxide with respect to 100 parts by mass of a blend of less than part and polyolefin. The non-halogen flame-retardant electric wire according to claim 1, wherein the blend contains 5 to 40 parts by mass of the polyolefin with respect to 60 to 95 parts by mass of the reactor blend type polyolefin-based thermoplastic resin.   The non-halogen flame-retardant electric wire according to claim 1, wherein the polyolefin contains at least one of a crystalline resin and a polar rubber. In non-halogen flame retardant cable insulation is coated on the outer periphery of the metal conductor, the insulator is 100 mass greater than 50 parts by weight reactor blend type polyolefin-based thermoplastic resin containing 51 to 85 mol% of a crystalline polypropylene in monomer unit A halogen-free flame retardant cable comprising 40 to 300 parts by mass of a metal hydroxide with respect to 100 parts by mass of a blend of less than 10 parts and a polyolefin. The non-halogen flame retardant cable according to claim 4, wherein the blend contains 5 to 40 parts by mass of the polyolefin with respect to 60 to 95 parts by mass of the reactor blend type polyolefin-based thermoplastic resin.   The non-halogen flame-retardant cable according to claim 4 or 5, wherein the polyolefin contains at least one of crystalline resin and polar rubber.

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