JP5410192B2 - Flame retardant resin composition, insulated wire, sheath and cable using the same - Google Patents

Description

  The present invention relates to a flame retardant resin composition, an insulated wire using the same, a sheath, and a cable.

  Polyvinyl chloride compositions are widely used in wire coatings, tubes, tapes, packaging materials, building materials, etc. because of their good electrical insulation and excellent flame retardancy and mechanical properties. Lead-free polyvinyl chloride resin that does not use lead as a stabilizer is becoming mainstream because of concerns about the effects on the human body.

  The lead-free polyvinyl chloride resin contains chlorine atoms in its molecular structure, and generates toxic and harmful chlorine gas during combustion. Therefore, a vinyl chloride electric wire replacement using a so-called eco-material with higher safety is being studied.

  As such an eco-material, a flame retardant composed of metal hydroxide particles such as magnesium hydroxide and aluminum hydroxide, and a flame retardant assistant composed of silicone compounds such as gum silicone oil, based on polyolefin resin. Additives are known (see Patent Document 1 below).

Japanese Patent No. 3193017

  By the way, an insulated wire is manufactured by melting a flame retardant composition with an extruder, extruding it from a crosshead, and covering the conductor passing through the crosshead to form an insulating layer. Here, in the cross head, a cylindrical space communicating with the discharge port of the extruder is formed, and when the flame retardant resin composition is injected into the cylindrical space from the discharge port of the extruder, the cylindrical space Go around the whole. At this time, the resin composition joins at a position away from the discharge port to form a tubular extrudate, and the tubular extrudate covers the conductor.

  Here, when forming a tube-like extrudate, a seam is not usually generated in a portion where the resin composition joins.

  However, the present inventors blended a silicone compound with the base resin in the flame retardant resin composition, and when the blending ratio increases, a seam is generated in the resulting insulating layer, and the seam is cracked. It has been found that this may occur. If the seam is cracked in this way, it cannot be used as an insulated wire, and the production yield of the insulated wire is reduced. Therefore, it is desirable to suppress the occurrence of such cracks in the seam in the insulating layer of the insulated wire. Such suppression of the occurrence of cracks in the seam is also desired when the flame retardant resin composition is used for the sheath of the insulated wire.

  In general, the flame-retardant resin composition is also required to be able to produce an insulated wire having both excellent mechanical properties and flame retardancy. However, the flame retardant resin composition described in Patent Document 1 still has room for improvement in terms of flame retardancy.

  The present invention has been made in view of the above circumstances, a flame retardant resin composition that can sufficiently suppress the occurrence of cracks in the seam of an insulating layer and a sheath while achieving both excellent mechanical properties and flame retardancy, It aims at providing the insulated wire, sheath, and cable using this.

  As a result of intensive studies to solve the above problems, the present inventors have blended an acrylate polymer produced by a tubular method into a base resin, and set the MFR (melt flow rate) of the acrylate polymer to a specific range. In addition, the inventors have found that the above problem can be solved by setting the blending ratio of the silicone compound to the base resin within a specific range, and the present invention has been completed.

That is, the present invention comprises a base resin containing 50% by mass or more of an acrylate polymer that is manufactured by a tubular method and has an MFR measured at 190 ° C. and a load of 2.16 kg of 0.5 (g / 10 min) or less, Metal hydroxide particles blended at a rate of 4 to 150 parts by weight with respect to 100 parts by weight of the base resin, and a silicone compound blended at a rate of 1 to 20 parts by weight with respect to 100 parts by weight of the base resin And a flame retardant resin composition.

  According to the flame-retardant resin composition of the present invention, it is possible to sufficiently suppress the occurrence of cracks in the seam of the insulating layer and the sheath while achieving both excellent mechanical properties and flame retardancy.

  In addition, the present inventors speculate as follows about the reason why more excellent flame retardancy is obtained in the flame retardant resin composition of the present invention.

  That is, firstly, it is considered that the mechanism for developing the flame retardancy when using a silicone compound as a flame retardant aid is as follows. That is, when the flame retardant resin composition is ignited in the combustion test, the fire type portion is carbonized to form a shell made of carbide (char). When such a shell is formed, it becomes difficult for oxygen to be supplied to the resin melted inside the shell, so that the resin becomes difficult to burn and extinguishes. Conventionally, even if the ignition is confirmed, the flame continues to be applied, and if the resin melted inside the shell suddenly foams, the shell is pushed up from the inside, causing cracks, and oxygen is supplied from there. Flame retardancy may be impaired. According to the flame retardant resin composition of the present invention, by setting the MFR of the acrylate polymer to a low value as described above, the foaming speed of the molten resin during the combustion test is reduced, and the shell is cracked. Therefore, it is speculated that excellent flame retardancy may be obtained.

  In addition, the present inventors infer the reason why the occurrence of cracks in the seam is suppressed as follows.

  That is, when the compounding amount of the silicone compound with respect to the base resin increases, the present inventors have a tendency that the silicone compound is unevenly distributed in the seam of the tubular extrudate obtained by extruding the flame retardant resin composition. It became clear by these studies. From this, it is considered that the seam portion becomes brittle and cracking is likely to occur. Therefore, when the compounding amount of the silicone compound relative to the base resin was reduced, the uneven distribution of the silicone compound was not recognized, so that the brittleness of the seam portion was eliminated, thereby suppressing the occurrence of cracks. The present inventors infer that.

The present invention includes a conductor, and an insulating layer covering the conductor, the insulating layer, Ru insulated wire der characterized in that it is composed of the flame-retardant resin composition.

  Moreover, the sheath characterized by providing the said flame-retardant resin composition may be sufficient as this invention.

The present invention further includes an insulated wire having a conductor and an insulating layer covering the conductor, and a sheath covering the insulated wire, wherein at least one of the insulating layer and the sheath is composed of the flame retardant resin composition. but it may also be a cable, characterized in that it is.

  According to the present invention, a flame retardant resin composition capable of sufficiently suppressing the occurrence of cracks in the seam of an insulating layer or a sheath while achieving both excellent mechanical properties and flame retardancy, an insulated wire using the same, a sheath, and A cable is provided.

It is a partial side view which shows one Embodiment of the cable of this invention. It is sectional drawing along the II-II line of FIG.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to FIG.

[cable]
FIG. 1 is a partial side view showing an embodiment of a cable according to the present invention, and shows a flat cable for indoor wiring. FIG. 2 is a cross-sectional view taken along the line II-II in FIG. As shown in FIG. 1, the flat cable 10 includes two insulated wires 4 and a sheath 3 that covers the two insulated wires 4. The insulated wire 4 includes an inner conductor 1 and an insulating layer 2 that covers the inner conductor 1.

Here, the insulating layer 2 and the sheath 4 of the insulated wire 4 are made of a flame retardant resin composition. This flame-retardant resin composition is produced by a tubular method and contains 50% by mass or more of an acrylate polymer having an MFR measured at 190 ° C. under a load of 2.16 kg of 0.5 (g / 10 min) or less. Base resin, metal hydroxide particles blended at a ratio of 4 to 150 parts by weight with respect to 100 parts by weight of the base resin, and silicone blended at a ratio of 1 to 20 parts by weight with respect to 100 parts by weight of the base resin Compound.

[Cable manufacturing method]
Next, the manufacturing method of the flat cable 10 mentioned above is demonstrated.

(conductor)
First, the inner conductor 1 is prepared. The inner conductor 1 may be composed of only one strand, or may be configured by bundling a plurality of strands. Further, the inner conductor 1 is not particularly limited with respect to the conductor diameter, the material of the conductor, and the like, and can be appropriately determined according to the application.

(Flame retardant resin composition)
On the other hand, the flame retardant resin composition is prepared. As described above, the flame retardant resin composition is manufactured by a tubular method, and 50 acrylate polymers having an MFR measured at 190 ° C. under a load of 2.16 kg of 0.5 (g / 10 min) or less. At a ratio of 1 to 20 parts by mass with respect to 100 parts by mass of the base resin, 100% by mass of the base resin, 4 to 150 parts by mass of the metal hydroxide particles blended at a rate of 4 to 150 parts by mass. And a silicone compound to be blended.

(Base resin)
As described above, the base resin is manufactured by a tubular method, and includes 50% by mass or more of an acrylate polymer having an MFR of 0.5 (g / 10 min) or less measured at 190 ° C. and a load of 2.16 kg. As long as it is a thing, the mixture of the said acrylate-type polymer and another polymer may be sufficient, and it may be comprised only with the said acrylate-type polymer. In addition, when MFR of an acrylate-type polymer becomes larger than 0.5 (g / 10min), a flame retardance will fall notably. Further, even if the MFR of the acrylate polymer is 0.5 (g / 10 min) or less, if the content of the acrylate polymer in the base resin is less than 50% by mass, the flame retardancy is significantly reduced.

  The MFR of the acrylate polymer is preferably 0.4 (g / 10 min) or less, more preferably 0.35 (g / 10 min) or less. However, MFR is preferably 0.2 (g / 10 min) or more, and more preferably 0.25 (g / 10 min) or more, because the extrudability deteriorates if MFR is too low.

  There are an autoclave method, a tubular method, and the like as methods for producing an acrylate polymer, but it is known that the branched structure, molecular weight distribution, and functional group distribution of the polymer obtained by the production method are different. As a result, even if the polymer has the same composition, the physical properties may vary greatly. Specifically, an insulated wire manufactured using an acrylate polymer produced by an autoclave method was produced using an acrylate polymer produced by a tubular method, whereas it exhibited insufficient flame retardancy. Insulated wires can have excellent flame retardancy. Therefore, in the present invention, an acrylate polymer manufactured using a tubular method is used.

  As the acrylate polymer, a copolymer of olefin and acrylate can be used. When a copolymer of an olefin and an acrylate is used as the acrylate polymer, examples of the olefin include ethylene, propylene, and butylene, and examples of the acrylate include methyl (meth) acrylate, methyl acrylate, ethyl acrylate, and the like. Is mentioned. More specifically, examples of the acrylate polymer include ethylene-ethyl acrylate (hereinafter referred to as “EEA”), ethylene-methyl acrylate (EMA), ethylene-methyl methacrylate (EMMA), and ethylene-butyl acrylate (EBA). Etc. are used. These acrylate polymers can be used alone or in admixture of two or more.

  When the base resin is a mixture of an acrylate polymer and another polymer, examples of the other polymer include ethylene-vinyl acetate (hereinafter referred to as “EVA”), ethylene propylene rubber (hereinafter referred to as “EPR”). , Olefin elastomers such as high density polyethylene (HDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), polypropylene, ethylene propylene copolymer, styrene-butadiene-styrene block copolymer (SBS) Styrene-isoprene-styrene block copolymer (SIS), styrene-ethylene / butylene-styrene block copolymer (SEBS), styrene-ethylene / propylene-styrene block copolymer (SEPS), partially hydrogenated styrene-ethylene / Butylene Ren block copolymer (partially hydrogenated SEBS), styrene (ethylene - ethylene / propylene) - styrene-based thermoplastic elastomers such as styrene block copolymer (SEEPS), and the like of these acid-modified products thereof.

  The content of the acrylate polymer in the base resin is preferably 60 to 100% by mass, and more preferably 60 to 80% by mass.

  As for the MFR of the acrylate polymer, in addition to purchasing various commercially available products having the desired MFR, for example, after melting and mixing the acrylate polymer and an organic peroxide such as dicumyl peroxide, the critical temperature of the organic peroxide It can adjust by generating a radical by the above heat processing and performing a micro-crosslinking process.

(Metal hydroxide particles)
The metal hydroxide particles are composed of metal hydroxide. Examples of the metal hydroxide include magnesium hydroxide, calcium hydroxide, and aluminum hydroxide. Among these, magnesium hydroxide is preferable. This is because the extrudability and flame retardancy when coating the inner conductor 1 can be improved.

The metal hydroxide particles are included at a rate of 4 to 150 parts by mass with respect to 100 parts by mass of the base resin, preferably 30 to 100 parts by mass, and 30 to 80 parts by mass. More preferably, it is contained in a proportion. When the proportion of the metal hydroxide particles exceeds 150 parts by mass, the mechanical properties are lowered, and when the proportion of the metal hydroxide particles is less than 4 parts by mass, the flame retardancy is lowered. From the viewpoint of recyclability, the amount of metal hydroxide added is preferably about 50 parts by mass or less. By making the addition amount of metal hydroxide about 50 parts by mass or less, the specific gravity of the resin composition becomes about 1.15 or less, cross-linked polyethylene (specific gravity 0.9), polyvinyl chloride (specific gravity about 1.4), conventional ecomaterial ( Specific gravity can be separated from the specific gravity of about 1.4).

(Silicone compound)
The silicone compound functions as a flame retardant aid, and examples thereof include polyorganosiloxane (silicone powder, silicone gum, silicone resin). Here, the polyorganosiloxane has a siloxane bond as a main chain and an organic group in a side chain. Examples of the organic group include a methyl group, a vinyl group, an ethyl group, a propyl group, and a phenyl group. Specific examples of the polyorganosiloxane include dimethylpolysiloxane, methylethylpolysiloxane, methyloctylpolysiloxane, methylvinylpolysiloxane, methylphenylpolysiloxane, and methyl (3,3,3-trifluoropropyl) polysiloxane. Is mentioned.

  As described above, the silicone compound is contained at a ratio of 1 to 20 parts by mass with respect to 100 parts by mass of the base resin. When the silicone compound is contained in a proportion of less than 1 part by mass, flame retardancy is reduced. On the other hand, if the silicone compound is contained in a proportion exceeding 20 parts by mass, cracks occur in the seam of the insulating layer 2 and the production yield of the insulated wires 4 is greatly reduced. The silicone compound is preferably contained in a proportion of 1 to 10 parts by mass and more preferably in a proportion of 2 to 8 parts by mass with respect to 100 parts by mass of the base resin.

  The silicone compound may be attached in advance to the surface of the metal hydroxide particles. In this case, it is preferable that the entire metal hydroxide particles contained in the flame retardant resin composition are coated with a silicone compound.

  As a method of attaching the silicone compound to the surface of the metal hydroxide particles, for example, the silicone compound is added to and mixed with the metal hydroxide particles to obtain a mixture, and then the mixture is heated at 40 to 75 ° C. It can be obtained by drying for 10 to 40 minutes and grinding the dried mixture with a Henschel mixer, an atomizer or the like.

  The flame retardant resin composition may contain a filler such as an antioxidant, an ultraviolet degradation inhibitor, a processing aid, a color pigment, a lubricant, carbon black, a crosslinking agent, and a crosslinking aid as necessary.

  The flame retardant resin composition can be obtained by kneading the base resin, a material in which a silicone compound is previously attached to the surface of the metal hydroxide particles, or the like, if necessary. The silicone compound may be added at the time of kneading without previously attaching to the surface of the metal hydroxide particles. The kneading can be performed with a kneading machine such as a Banbury mixer, a tumbler, a pressure kneader, a kneading extruder, a twin screw extruder, a mixing roll, and the like.

  Next, the inner conductor 1 is covered with the flame retardant resin composition. Specifically, the flame retardant resin composition described above is melt-kneaded using an extruder, injected from the discharge port of the extruder into a cylindrical space formed in the crosshead, and into the cylindrical space. A tubular extrudate is formed. And this tubular extrudate is continuously coat | covered on the internal conductor 1 which passes a crosshead. Thus, the insulated wire 4 is obtained.

(sheath)
Finally, two insulated wires 4 obtained as described above are prepared, and these insulated wires 4 are covered with a sheath 3 made using the flame retardant resin composition. The sheath 3 protects the insulating layer from physical or chemical damage.

  The flat cable 10 is obtained as described above.

  According to the method for manufacturing the flat cable 10 described above, the occurrence of cracks in the seam of the insulating layer 2 and the sheath 3 can be sufficiently suppressed while achieving both excellent mechanical properties and flame retardancy.

  The present invention is not limited to the above embodiment. For example, although the flat cable 10 has two insulated wires 4 in the above-described embodiment, the flat cable 10 may have only one insulated wire 4 or may have three or more wires. .

  Moreover, in the said embodiment, although the insulating layer 2 and the sheath 4 of the insulated wire 4 are comprised with said flame-retardant resin composition, the insulating layer 2 is comprised with normal insulating resin, and only the sheath 3 is an insulating layer. 2 may be comprised of a flame retardant resin composition.

  Hereinafter, the content of the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to the following examples.

(Examples 1-12 and Comparative Examples 1-15)
EVA, EPR, EEA1, EEA2, EEA3, EEA4, magnesium hydroxide (hereinafter referred to as “magnesium hydroxide” is referred to as “Mg hydroxide”) 1, Mg hydroxide 2, Mg hydroxide and Mg hydroxide are shown in Table 1 and They were blended at the blending ratio shown in Table 2, and kneaded for 15 minutes at 160 ° C. with a Banbury mixer to obtain a flame retardant resin composition. In Tables 1 and 2, the unit of the blending amount of each blending component is part by mass. The blending amounts of Mg1, Mg2, Mg3, and Mg4 indicate the total amount of Mg hydroxide that has not been surface treated and polyorganosiloxane that has been surface treated. In parentheses, the blending amount of Mg hydroxide not surface-treated and the blending amount of polyorganosiloxane surface-treating this Mg hydroxide (the blending amount of Mg hydroxide not surface-treated) ) / (Polyorganosiloxane blending amount). The blending amount of the polyorganosiloxane is calculated by multiplying the blending amount of the Mg hydroxides 1 to 4 described in Tables 1 and 2 by the following surface treatment rate.

Specifically, the following EVA, EPR, EEA1, EEA2, EEA3, EEA4, Mg hydroxide, Mg hydroxide, Mg hydroxide, and Mg hydroxide were the following (1) to (10).
(1) EVA
EV460 (trade name, manufactured by Mitsui DuPont Polychemical Co., Ltd.)
(2) EPR
EPT # 3045 (trade name, manufactured by Mitsui Chemicals)
(3) EEA1
A-710 (trade name, MFR: 0.5 g / 10 min, manufactured by Mitsui DuPont Polychemical Co., Ltd., autoclave method)
(4) EEA2
Elvalloy 2116AC low MFR product (trade name, MFR: 0.3 g / 10 min, manufactured by DuPont, tubular method)
(5) EEA3
Elvalloy 2116AC (trade name, MFR: 0.9 g / 10 min, manufactured by DuPont, tubular method)
(6) EEA4
ZE708 (trade name, MFR: 0.5 g / 10 min, manufactured by Ube Maruzen Polyethylene Co., Ltd., tubular method)
(7) Mg hydroxide 1
Mg hydroxide surface-treated with polyorganosiloxane about 6% (surface treatment rate 6%, manufactured by Shin-Etsu Chemical Co., Ltd.)
(8) Hydroxide Mg2
Mg hydroxide surface-treated with polyorganosiloxane about 10% (surface treatment rate 10%, manufactured by Shin-Etsu Chemical Co., Ltd.)
(9) Mg3 hydroxide
Mg hydroxide surface-treated with polyorganosiloxane about 3% (surface treatment rate 3%, manufactured by Shin-Etsu Chemical Co., Ltd.)
(10) Hydroxide Mg4
Mg hydroxide surface-treated with polyorganosiloxane about 20% (surface treatment rate 20%, manufactured by Shin-Etsu Chemical Co., Ltd.)

Next, this flame retardant resin composition was kneaded at 160 ° C. for 15 minutes by a Banbury mixer. Thereafter, the flame retardant resin composition was put into a single screw extruder (L / D = 20, screw shape: full flight screw, manufactured by Mars Seiki Co., Ltd.), and the cylinder in the crosshead was discharged from the discharge port of the extruder. A flame-retardant resin composition is injected into the cylindrical space, and a tube-shaped extrudate is extruded from the cylindrical space to a thickness of 0.8 mm on the conductor (number of strands 7 / strand diameter 0.6 mm). Was coated as follows. Thus, an insulated wire having an outer diameter of 3.4 mm was obtained.

  About the insulated wires of Examples 1 to 12 and Comparative Examples 1 to 15 obtained as described above, the mechanical properties and flame retardancy were evaluated as follows, and the insulating layer was evaluated as follows. The presence or absence of cracks in the seam was evaluated.

(Mechanical properties)
The mechanical properties were evaluated by conducting a tensile test on the insulated wires of Examples 1 to 12 and Comparative Examples 1 to 15 according to JIS standard C3005. The results are shown in Tables 1 and 2. In Table 1 and Table 2, those having a tensile strength of 10 MPa or more are indicated as “◯” as acceptable, and those having a tensile strength of less than 10 MPa are indicated as “x” as rejected. In the tensile test, the tensile speed was 200 mm / min, and the distance between the marked lines was 20 mm.

(Flame retardance)
About the insulated wire of Examples 1-12 and Comparative Examples 1-15, the 60 degree inclination combustion test of JIS K3005 was done and the flame retardance was evaluated. At this time, the flame retardancy when the flame contact time was 15 seconds was evaluated. The results are shown in Tables 1 and 2. In Table 1 and Table 2, for each example and comparative example, 10 insulated wires were prepared and subjected to a flame retardancy test. “O” is displayed, 4 to 8 fire-extinguished insulated wires are indicated as “Fail” as “Fail 1”, and 0 to 3 fire-insulated wires are indicated as “Fail” as “Fail”. .

(Check for seam cracks)
About the insulated wire of Examples 1-12 and Comparative Examples 1-15, the seam was observed with the optical microscope, and the presence or absence of the generation | occurrence | production of the crack in a seam was investigated. The results are shown in Tables 1 and 2. In Tables 1 and 2, an insulated wire having a crack in the seam is indicated as “O” as a pass, and an insulated wire having no crack in the seam is indicated as “X” as a failure. In addition, about the insulated wire of Examples 1-12 and Comparative Examples 1-15, when the elemental analysis by EPMA was performed, in the insulated wire of the comparative example 3 by which generation | occurrence | production of the crack in a seam was recognized, the element derived from siloxane, That is, Si was unevenly distributed in the seam, but in the insulated wires of Examples 1 to 12, Comparative Examples 1 and 2, and Comparative Examples 4 to 15 in which no crack was observed in the seam, Si was unevenly distributed. I was not able to admit.

  From the results shown in Table 1 and Table 2, the insulated wires of Examples 1 to 12 have both excellent mechanical properties and flame retardancy compared to the insulated wires of Comparative Examples 1 to 15, and It was found that the occurrence of cracks in the seam can be sufficiently suppressed.

  From this, it was confirmed that according to the flame retardant resin composition of the present invention, the occurrence of cracks in the seam of the insulating layer or sheath can be sufficiently suppressed while achieving both excellent mechanical properties and flame retardancy.

DESCRIPTION OF SYMBOLS 1 ... Internal conductor, 2 ... Insulating layer, 3 ... Sheath, 4 ... Insulated electric wire, 10 ... Flat cable.

Claims (4)

A base resin containing 50% by mass or more of an acrylate polymer that is manufactured by a tubular method and has an MFR of 0.5 (g / 10 min) or less measured at 190 ° C. and a load of 2.16 kg;
Metal hydroxide particles blended at a ratio of 4 to 150 parts by mass with respect to 100 parts by mass of the base resin;
A silicone compound compounded at a ratio of 1 to 20 parts by mass with respect to 100 parts by mass of the base resin;
A flame retardant resin composition comprising: Conductors,
An insulating layer covering the conductor;
With
The insulating layer is composed of the flame retardant resin composition according to claim 1,
Insulated wire characterized by   A sheath comprising the flame retardant resin composition according to claim 1. An insulated wire having an inner conductor and an insulating layer covering the inner conductor;
A sheath for covering the insulated wire,
Cable, wherein at least one of the insulating layer and the sheath is made of a flame-retardant resin composition according to claim 1.

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