JP2017186416A - Fire retardant batch, wire and cable formed by using the same and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a coating layer less in aggregation of a fire retardant and excellent in fire retardancy.SOLUTION: There is provided a fire retardant batch for adding fire retardancy by blending the same to a silane batch containing a silane graft polymer by graft polymerizing a silane compound to a polymer, containing (A) silane graft polyolefin by graft polymerizing the silane compound to polyolefin (a) in a presence of a free radical generator and (B) a fire retardant containing at least 3 of an antimony compound, a boron-based fire retardant, a melamine-based fire retardant, magnesium hydroxide and aluminum hydroxide and the fire retardant (B) is at 60 pts.mass to 300 pts.mass based on 100 pts.mass of the polyolefin (a).SELECTED DRAWING: Figure 1

Description

  The present invention relates to a flame retardant batch, an electric wire / cable formed using the same, and a method for manufacturing the same.

  An electric wire / cable used for supplying electric power to an electric device or transmitting an electric signal is provided with an insulating layer or a sheath as a coating layer on the surface thereof.

  Since wires and cables are sometimes used in a high temperature environment, the coating layer is required to have heat resistance. As a method for improving the heat resistance, there is a method of subjecting the coating material of the coating layer to a crosslinking treatment. Examples of the crosslinking treatment include electron beam crosslinking, chemical crosslinking, and silane crosslinking. Among these, silane crosslinking is employed in various fields because it does not require special equipment.

  In the silane crosslinking, a silane compound (for example, a silane coupling agent) is graft polymerized to a polymer in the presence of a free radical generator to obtain a silane graft polymer, and then the silane graft polymer is moistureated in the presence of a silanol condensation catalyst. This is a method of introducing a cross-linked structure by bringing it into contact.

  Specifically, when forming a coating layer of an electric wire or cable by silane crosslinking, first, a silane batch containing a silane graft polymer and a catalyst batch containing a silanol condensation catalyst (hereinafter also simply referred to as a catalyst) and a polymer are melted. Mix while mixing. Subsequently, the mixture is extruded onto the outer periphery of the conductor and molded. Then, the compact is brought into contact with water to give silane crosslinking.

  Moreover, since a flame retardance is requested | required by the coating layer, the flame retardant which provides a flame retardance is mix | blended. As this blending method, for example, a flame retardant is blended with a polymer to form a flame retardant batch, and this is mixed with a silane batch before extrusion, or a flame retardant is blended with a catalyst batch or the like in advance to obtain a silane batch. (For example, refer to Patent Document 1).

JP 2008-297453 A

  However, in the method shown in Patent Document 1, since the fluidity of the silane graft polymer contained in the silane batch is low, when the flame retardant batch is mixed with the silane batch, the flame retardant cannot be uniformly dispersed in the silane graft polymer. It is difficult to impart sufficient flame retardancy to the coating layer. In order to improve the flame retardancy, it may be possible to increase the amount of the flame retardant, but in this case, the flame retardant may aggregate, and the surface of the coating layer is roughened by the aggregate and the surface smoothness is impaired. The mechanical properties (for example, tensile strength and elongation) of the coating layer also deteriorate.

  Accordingly, an object of the present invention is to provide a technique for forming a coating layer with less flame retardant aggregation and excellent flame retardancy by silane crosslinking.

According to one aspect of the invention,
A flame retardant batch for blending with a silane batch containing a silane graft polymer in which a silane compound is graft-polymerized to a polymer to impart flame retardancy,
A silane-grafted polyolefin (A) obtained by graft-polymerizing a silane compound to the polyolefin (a) in the presence of a free radical generator;
An antimony compound, a brominated flame retardant, a melamine flame retardant, a flame retardant containing at least three of magnesium hydroxide and aluminum hydroxide (B), and
There is provided a flame retardant batch containing the flame retardant (B) in an amount of 60 parts by mass to 300 parts by mass with respect to 100 parts by mass of the polyolefin (a).

According to another aspect of the invention,
A polyolefin (a), a silane compound, a free radical generator, a flame retardant (B) containing at least three of an antimony compound, a brominated flame retardant, a melamine flame retardant, magnesium hydroxide and aluminum hydroxide. While mixing, the polyolefin (a) is graft-polymerized with the silane compound in the presence of the free radical generator to form the silane-grafted polyolefin (A). A flame retardant batch preparation step to obtain a flame retardant batch by dispersing
An extrusion step of mixing the flame retardant batch and a silane batch containing a silane graft polymer in which a silane compound is graft-polymerized to the polymer, and extruding the mixture so as to cover the outer periphery of the conductor;
There is provided a method of manufacturing an electric wire / cable having a crosslinking step of forming a coating layer by silane crosslinking the molded body.

According to yet another aspect of the invention,
Comprising a conductor and a coating layer disposed on the outer periphery of the conductor;
The coating layer is obtained by crosslinking a mixture containing a silane batch containing a silane graft polymer obtained by graft polymerization of a silane compound to a polymer and a flame retardant batch,
The flame retardant batch is
A silane-grafted polyolefin (A) obtained by graft-polymerizing a silane compound to the polyolefin (a) in the presence of a free radical generator;
An antimony compound, a brominated flame retardant, a melamine flame retardant, a flame retardant containing at least three of magnesium hydroxide and aluminum hydroxide (B), and
An electric wire / cable containing the flame retardant (B) so as to be 60 parts by mass or more and 300 parts by mass or less with respect to 100 parts by mass of the polyolefin (a) is provided.

  According to the present invention, a coating layer having little flame retardant aggregation and excellent flame retardancy can be formed by silane crosslinking.

It is a figure which shows a cross section perpendicular | vertical to the length direction of the electric wire which concerns on one Embodiment of this invention. It is a figure which shows the cross section perpendicular | vertical to the length direction of the cable which concerns on one Embodiment of this invention.

  In order to solve the above-mentioned problems, the present inventors have studied a flame-retardant batch that contains a silane-grafted polymer, can be easily mixed with a silane batch having low fluidity, and can uniformly disperse a flame retardant. As a result, it has been found that the dispersion medium in which the flame retardant is dispersed in the flame retardant batch may be changed to a silane-grafted polyolefin in which a silane compound is graft-polymerized in the same manner as the silane batch instead of the conventional polymer. That is, it has been found that a flame retardant batch may be constituted by dispersing a flame retardant in silane-grafted polyolefin. According to such a flame-retardant batch, since it is easy to mix with a silane batch, it is thought that the dispersion | distribution of a flame retardant can be promoted as a result and aggregation can be suppressed.

  However, in this case, when preparing the flame retardant batch, the flame retardant is dispersed in the silane-grafted polyolefin with low fluidity, so the dispersibility in the flame retardant batch becomes insufficient and mixed with the silane batch. It was found that the dispersibility was insufficient.

  Therefore, the present inventors examined a method for uniformly dispersing the flame retardant in the silane-grafted polyolefin in the flame retardant batch. As a result, it was found that the number of flame retardants to be blended should be three or more instead of one. That is, it has been found that it is better to blend a plurality of different flame retardants than to blend one flame retardant in a large amount. As described above, by using a plurality of different flame retardants, the amount of each flame retardant can be reduced even when blended so that the total amount becomes large, so that aggregation of the same flame retardant can be easily suppressed. Therefore, each flame retardant can be dispersed in the silane-grafted polyolefin having low fluidity without agglomeration. And, according to such a flame retardant batch in which a plurality of different flame retardants are uniformly dispersed, it is easy to mix with a silane batch and the aggregation of the flame retardant can be suppressed. Deterioration of smoothness and mechanical properties are suppressed, and a coating layer satisfying these properties at a high level can be formed.

  The present invention has been made based on the above findings and is as follows.

<One Embodiment of the Present Invention>
Hereinafter, an embodiment of the present invention will be described.
In the present specification, a numerical range represented by using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.

[Flame Retardant Batch]
The flame retardant batch is a component for imparting flame retardancy by blending with a silane batch containing a flame retardant and containing a silane graft polymer in which a silane compound is graft-polymerized.

As described above, the flame retardant batch of the present embodiment is configured as follows from the viewpoint of enhancing the dispersibility of the flame retardant.
That is, the flame retardant batch comprises a silane-grafted polyolefin (A) obtained by graft polymerization of a silane compound to a polyolefin (a) in the presence of a free radical generator, an antimony compound, a brominated flame retardant, a melamine flame retardant, water A flame retardant (B) containing at least three of magnesium oxide and aluminum hydroxide, and the flame retardant (B) is 60 parts by mass or more and 300 parts by mass or less with respect to 100 parts by mass of the polyolefin (a). To be contained.

  Hereinafter, each component which comprises a flame-retardant batch is demonstrated.

(Silane-grafted polyolefin (A))
The silane-grafted polyolefin (A) is obtained by graft-polymerizing a silane compound to the polyolefin (a) in the presence of a free radical generator, and acts as a dispersion medium for dispersing the flame retardant (B) in a flame retardant batch. To do.

As polyolefin (a), if a silane compound can be graft-polymerized, it will not specifically limit, A well-known component can be used. For example, low density polyethylene (LDPE), linear low density polyethylene (LLDPE), ethylene-vinyl acetate copolymer (EVA), ethylene-ethyl acrylate copolymer, ethylene-methyl acrylate copolymer, ethylene-glycidyl methacrylate A copolymer or the like can be used.
Among these, EVA is particularly preferable. EVA has high acceptability of the silanol condensation catalyst (B) and other additives (for example, flame retardant), and can be uniformly dispersed without agglomeration even if they are blended in a large amount.

The silane compound is a silane coupling agent having an unsaturated bond group capable of reacting with a polymer and a hydrolyzable silane group capable of forming a crosslink by a silanol condensation reaction. A silane compound introduce | transduces a silane group into polyolefin (a) by being graft-polymerized by polyolefin (a).
As an unsaturated bond group, a vinyl group, a methacryl group, an acryl group, etc. are mentioned, for example. Examples of the hydrolyzable silane group include those having a hydrolyzable structure such as a halogen, an alkoxy group, an acyloxy group, and a phenoxy group. Examples of the silane group having a hydrolyzable structure include a halosilyl group, an alkoxysilyl group, an acyloxysilyl group, and a phenoxysilyl group.

  Although the compounding quantity of a silane compound is not specifically limited, It is preferable that it is 1-10 mass parts with respect to 100 mass parts of polyolefin (a). When the amount is less than 1 part by mass, when the coating layer is formed by silane crosslinking, a sufficient degree of crosslinking may not be obtained, and heat resistance may be lowered. On the other hand, when the amount exceeds 10 parts by mass, when the silane-grafted polyolefin (A) is formed by graft polymerization, the silane compounds easily react with each other to form a foreign substance (condensate). The surface smoothness may be impaired. From the viewpoint of achieving both heat resistance and surface smoothness at a high level, the blending amount of the silane compound is more preferably 2 to 6 parts by mass.

  The free radical generator is one that decomposes by heating to generate radicals. As the free radical generator, for example, an organic oxide can be used. Specifically, dicumyl peroxide, 1,1-di (t-butylperoxy) cyclohexane, t-butylperoxyisopropyl carbonate, t-amylperoxyisopropyl carbonate, 2,5 dimethyl 2,5 di (t -Butylperoxy) hexane, di-t-butyl peroxide, di-t-amyl peroxide, 1,1-di (t-amylperoxy) cyclohexane, t-butylperoxy 2-ethylhexyl carbonate, etc. Can do. These may be used alone or in combination of two or more.

  The blending amount of the free radical generator is not particularly limited, but is such an amount that the ratio of the silane compound to the free radical generator (silane compound / free radical generator) is preferably 5 to 400, more preferably 100 to 300. It is. When the ratio is less than 5 and the amount of the free radical generator is relatively large, the number of crosslinking points of the polymer increases, and the rate of crosslinking formation at the initial stage of the reaction becomes excessively high. There is a possibility that grains are formed due to the difference in viscosity and the surface smoothness is impaired. On the other hand, when the ratio exceeds 400, the amount of free radical generators is excessively decreased, so that a sufficient degree of crosslinking cannot be obtained and heat resistance may be lowered.

(Flame retardant (B))
As described above, in the present embodiment, a plurality of different types are used instead of one type in order to improve the dispersibility of the flame retardant (B) in the flame retardant batch. According to the study by the present inventors, it was found that as the flame retardant (B), it is preferable to use at least three of antimony compounds, bromine flame retardants, melamine flame retardants, magnesium hydroxide and aluminum hydroxide. . When using 1 type or 2 types as a flame retardant (B), since it is necessary to mix | blend each component comparatively many in order to obtain high flame retardance, a flame retardant aggregates and, as a result, coating | cover Not only the flame retardancy of the layer is lowered, but also the surface smoothness and mechanical properties are lowered.

  Antimony compounds exhibit an oxygen asphyxiation effect upon combustion. As the antimony compound, for example, antimony oxides such as antimony trioxide, antimony tetroxide, antimony pentoxide, and sodium antimonate can be used. Among these, antimony trioxide is preferable.

  The brominated flame retardant exhibits an oxygen suffocation effect by combustion, like the antimony compound. As the brominated flame retardant, known compounds can be used. For example, ethylene bispentabromobenzene, tetrabromobisphenol A-bis (2,3-dibromopropyl ether), decabromodiphenyl oxide, octabromodiphenyl Oxide, pentabromodiphenyl oxide, tetrabromobisphenol A, tetrabromobisphenol A-bis (allyl ether), tetrabromobisphenol A-bis (2-hydroxyether), hexabromocyclodecane, bis (tribromophenoxy) ethane, tetra Bromobisphenol A epoxy oligomer, tetrabromobisphenol A carbonate oligomer, ethylenebistetrabromophthalimide, poly-dibromophenylene oxide, 2,4,6 Tribromophenol, tetrabromobisphenol A-bis (acrylate), tetrabromophthalic anhydride, tetrabromophthalate diol, 2,3-dibromopropanol, tribromostyrene, tetrabromophenylmaleimide, poly (pentabromobenzyl) acrylate, Tris (tribromoneopentyl) phosphate, tris (dibromophenyl) phosphate, tris (tribromophenyl) phosphate, and the like can be used. These may be used alone or in combination of two or more.

  The melamine flame retardant exhibits an oxygen asphyxiation effect by combustion, like the antimony compound. As the melamine-based flame retardant, known compounds can be used, for example, melamine, melam, melem, melon, melamine cyanurate, melamine phosphate, melamine pyrophosphate, melamine polyphosphate, melamine / melam polyphosphate, Melem double salt, melamine alkylphosphonate, melamine phenylphosphonate, melamine sulfate, melam methanesulfonate, and the like. Among them, melamine cyanurate, melamine phosphate, melamine polyphosphate, melamine sulfate and the like can be used. These may be used alone or in combination of two or more. Among these, melamine cyanurate is particularly preferable.

  Magnesium hydroxide is dehydrated by combustion and exhibits an endothermic effect.

  Aluminum hydroxide, like magnesium hydroxide, dehydrates by combustion and exhibits an endothermic effect.

  From the viewpoint of dispersibility of the flame retardant (B), the combination of the flame retardant (B) is not particularly limited, but from the viewpoint of obtaining high flame retardant, a flame retardant (antimony compound, bromine-based) that exhibits an oxygen suffocation effect. It is preferable to use together a flame retardant and a melamine flame retardant) and a flame retardant (magnesium hydroxide and aluminum hydroxide) exhibiting an endothermic effect. This is because higher flame retardancy can be obtained by multiplying different flame retardant effects.

Moreover, as a combination of the flame retardant which expresses an oxygen suffocation effect, the following three combinations are preferable.
(B1) antimony compound and brominated flame retardant (b2) brominated flame retardant and melamine flame retardant (b3) antimony compound, brominated flame retardant and melamine flame retardant (b1) The compound and brominated flame retardant produce antimony bromide upon combustion, and this gas exerts a strong suffocation effect. According to the combination of (b2), the brominated flame retardant and the melamine based flame retardant generate suffocation gas in stages at different combustion temperatures during combustion, and exert a strong suffocation effect. According to the combination of (b3), the effect by the combination of (b1) and (b2) is expressed together.

  Thus, high flame retardancy can be obtained by using any combination of (b1) to (b3) and at least one of magnesium hydroxide and aluminum hydroxide in combination.

  Although the compounding quantity of a flame retardant (B) is not specifically limited, From a viewpoint of obtaining desired flame retardance, it is preferable that it is 60 mass parts-300 mass parts with respect to 100 mass parts of polyolefin (a). By setting it as 60 parts by mass or more, high flame retardancy can be obtained, and by setting it as 300 parts by mass or less, aggregation of the flame retardant (B) is suppressed, and surface smoothness and mechanical properties are reduced due to aggregation. Can be suppressed. From the viewpoint of obtaining higher flame retardancy, the blending amount of the flame retardant (B) is more preferably 80 parts by mass or more, and further preferably 140 parts by mass or more. By setting it as 80 mass parts or more, as demonstrated in the below-mentioned Example, the high flame retardance which passes a VFT test is obtained, and it passes the VW-1 test by setting it as 140 mass parts or more. Such higher flame retardancy can be obtained. In addition, it is good to mix | blend each component of a flame retardant (B) at least 20 mass parts or more with respect to 100 mass parts of polyolefin (a).

(Other additives)
Other additives may be blended in the flame retardant batch as necessary.

  For example, a silanol condensation catalyst can be blended for the purpose of accelerating the crosslinking reaction and improving the efficiency of introduction of silane crosslinking. As the silanol condensation catalyst, known compounds can be used, including, for example, group II elements such as magnesium and calcium, group VIII elements such as cobalt and iron, metal elements such as tin, zinc and titanium, and these elements. Metal compounds can be used. In addition, metal salts of octylic acid and adipic acid, amine compounds, acids, and the like can be used. Specifically, dioctyltin dineodecanoate, dibutyltin dilaurate, dibutyltin diacetate, dibutyltin dioctate, stannous acetate, stannous carblate, lead naphthenate, zinc caprylate, naphthene Cobalt acid or the like can be used. As the amine compound, ethylamine, dibutylamine, hexylamine, pyridine and the like can be used. As the acid, inorganic acids such as sulfuric acid and hydrochloric acid, and organic acids such as toluenesulfonic acid, acetic acid, stearic acid, and maleic acid can be used.

  The compounding quantity of a silanol condensation catalyst is 0.01 mass part-1 mass part with respect to 100 mass parts of polyolefin (a), and 0.03 mass part-0.3 mass part is preferable. If it is less than 0.01 parts by mass, a sufficient degree of crosslinking cannot be obtained, and the heat resistance may be lowered. On the other hand, when the amount exceeds 1 part by mass, crosslinking is likely to proceed before the silane batch is mixed and extruded, and the surface smoothness may be impaired.

  Further, for example, for the purpose of reducing the cost, a filler such as talc or calcium carbonate may be blended. In addition, for example, an ion trap agent such as baked clay or hydrotalcite may be blended for the purpose of improving the insulation of the coating layer. Further, for example, other additives such as a plasticizer, an antioxidant (including an anti-aging agent), a lubricant, a copper damage discoloration inhibitor, a crosslinking aid, and a stabilizer may be blended.

[Preparation of flame retardant batch]
Next, a method for preparing the above flame-retardant batch will be described.

  First, a flame retardant containing at least three of a silane compound, a free radical generator, an antimony compound, a brominated flame retardant, a melamine flame retardant, magnesium hydroxide and aluminum hydroxide with respect to the polyolefin (a) ( B) is added in a predetermined amount. By melt-kneading these at a predetermined temperature, the silane compound is graft-polymerized to the polyolefin (a) to form the silane-grafted polyolefin (A). At this time, the flame retardant (B) is dispersed in the polyolefin (a) having good fluidity before the graft polymerization and simultaneously with the melt polymerization and graft polymerization. In this embodiment, since several different kinds are used together as a flame retardant (B) and the compounding quantity of each component is decreased, a flame retardant (B) can be uniformly disperse | distributed, without agglomerating. That is, the flame retardant (B) in the silane-grafted polyolefin (A) is obtained by uniformly dispersing each component of the flame retardant (B) in the polyolefin (a) while graft polymerizing the silane compound to the polyolefin (a). It is possible to obtain a flame retardant batch in which is uniformly dispersed. Even if the flame retardant (B) is added after the graft polymerization and melt-kneaded, the fluidity of the silane-grafted polyolefin (A) is low, so that the flame retardant (B) aggregates and can be uniformly dispersed. It becomes difficult.

  In addition, when blending a silanol condensation catalyst into a flame retardant batch, while the polyolefin (a) or the flame retardant (B) is melt-kneaded, it may be charged in a liquid state, but it is difficult to charge as it is. If so, it may be added after impregnating with a filler or the like, or a catalyst batch in which a silanol condensation catalyst is blended with a polymer may be prepared separately.

  Moreover, when adding antioxidant as another additive, it is good to add, after predetermined time passes, after superposition | polymerization so that graft polymerization of a silane compound may not be inhibited. For example, it may be added simultaneously with the silanol condensation catalyst.

〔Electrical wire〕
Next, a method for producing an electric wire using the above-described flame retardant batch and a schematic structure of the electric wire will be described with reference to FIG. FIG. 1 is a view showing a cross section perpendicular to the length direction of an electric wire according to an embodiment of the present invention.

  First, the conductor 11 is prepared. As the conductor 11, for example, a copper wire made of low-oxygen copper, oxygen-free copper, or the like, a copper alloy wire, a metal wire made of aluminum, silver, or the like, or a stranded wire obtained by twisting metal wires can be used. The outer diameter of the conductor 11 can be appropriately changed according to the use of the electric wire 10.

  Subsequently, various batches for forming the insulating layer 12 as a coating layer are prepared. In this embodiment, a flame retardant batch containing a flame retardant and a silanol condensation catalyst and a silane batch containing a silane graft polymer are prepared.

  A flame retardant batch is prepared by preparing a polyolefin (a), a silane compound, a free radical generator, a flame retardant (B) and a silanol condensation catalyst, and dispersing the flame retardant (B) simultaneously with graft polymerization according to the procedure described above. Prepare with. In addition, at this time, you may mix | blend another additive (for example, antioxidant etc.) as needed, and may disperse | distribute it in a flame-retardant batch.

  The silane batch is prepared by preparing a polymer, a silane compound, and a free radical generator, and graft-polymerizing the silane compound to the polymer to form a silane-grafted polymer in the same manner as the flame retardant batch.

The polymer in the silane batch is not particularly limited, and may be appropriately changed according to the characteristics required for the insulating layer 12. From the viewpoint of flexibility, for example, EVA, ethylene-ethyl acrylate copolymer (EEA), ethylene-based α-olefin copolymer, or the like may be used. From the viewpoint of strength, for example, a propylene-based α-olefin copolymer may be used. From the viewpoint of achieving both flexibility and strength, these polymers are preferably used in combination.
As the silane compound to be graft-polymerized to the polymer, the above-described one may be used.

  Subsequently, the prepared flame-retardant batch and silane batch are melt-kneaded, and the kneaded product is extruded onto the outer periphery of the conductor 11 to be coated. In the flame retardant batch of the present embodiment, since the flame retardant (B) is dispersed in the silane-grafted polyolefin (A), when mixed with the silane batch, the flame retardant (B) is not agglomerated in the kneaded product. Can be dispersed. Thereby, generation | occurrence | production of the foreign material by aggregation of a flame retardant (B) can be reduced in the extruded molded object.

  The mixing ratio of the flame retardant batch and the silane batch at the time of extrusion is not particularly limited. From the viewpoint of obtaining higher flame retardancy, it is preferable to mix the flame retardant batch and the silane batch within a range of 99: 1 to 20:80, preferably within a range of 99: 1 to 30:70. .

  Subsequently, the molded body is exposed to, for example, the atmosphere and brought into contact with moisture. Thereby, each silane group of a silane graft polyolefin (A) and a silane graft polymer is hydrolyzed to make a silanol group. Then, these silanol groups are dehydrated and condensed with a silanol condensation catalyst to introduce a crosslinked structure. Thus, the electrically insulating insulating layer 12 made of a crosslinked silane is formed by silane crosslinking the mixture of the catalyst batch and the silane batch.

  The electric wire 10 of this embodiment is obtained by the above.

<Effects according to this embodiment>
According to the present embodiment, the following one or more effects are achieved.

  The flame retardant batch of the present embodiment includes a silane-grafted polyolefin (A) and at least three different types of flame retardants (B). By blending a plurality of different flame retardants (B), the amount of each flame retardant can be reduced even when blended so that the total amount becomes large, and it becomes easy to suppress aggregation of the same flame retardant. That is, the flame retardant batch of this embodiment is configured such that the flame retardant (B) is uniformly dispersed in the silane-grafted polyolefin (A). According to such a flame retardant batch, it is easy to mix with the silane batch containing the silane graft polymer, so when the flame retardant batch and the silane batch are mixed, the flame retardant is not dispersed in the mixture evenly. It becomes possible to make it. Therefore, according to the flame retardant batch of this embodiment, the flame retardancy is high, the surface smoothness and mechanical properties due to aggregation of the flame retardant are suppressed, and a coating layer having these properties at a high level is formed. be able to.

<Other Embodiments of the Present Invention>
As mentioned above, although one Embodiment of this invention was described concretely, this invention is not limited to the above-mentioned embodiment, In the range which does not deviate from the summary, it can change suitably.

  In the above-described embodiment, the silanol condensation catalyst is blended with the flame retardant batch, and the flame retardant batch and the silane batch are mixed and extruded to form the coating layer, but the present invention is not limited to this. For example, a silanol condensation catalyst is not blended in a flame retardant batch, but is dispersed in a polymer to form a catalyst batch. The catalyst batch, the flame retardant batch, and a silane batch are mixed at a predetermined ratio and extruded to form a coating layer. It may be formed.

  Moreover, although the above-mentioned embodiment demonstrated the case where the insulating layer 12 of the electric wire 10 was formed as a coating layer, in this invention, as shown in FIG. 2, the electrical insulation property of the cable 20 using the above-mentioned catalyst batch. The sheath 25 may be formed. Specifically, three wires 23 each having an insulating layer 22 provided on the outer periphery of the conductor 21 are twisted together and pressed with a pressing tape 24 or the like, and a sheath 25 is formed on the outer periphery thereof. The sheath 25 may be formed in the same manner as the insulating layer 12 described in the above embodiment.

  In addition, although the case where the three electric wires 23 are twisted together is illustrated in FIG. 2, the number of the electric wires 23 is not limited to this, and can be changed as appropriate.

  EXAMPLES Next, although this invention is demonstrated in detail based on an Example, this invention is not limited to these Examples.

In this example, the following materials were used.
Polyolefin EVA Everflex V5274: Mitsui DuPont Polychemical Co., Ltd. Polyolefin LLDPE NLTCG5130: NUC Co., Ltd. Polyolefin HDPE Hi-Zex 5305E: Prime Polymer Co., Ltd. Silane Compound KBM-1003: Shin-Etsu Chemical Co., Ltd. Free Radical generator Park mill D: NOF Corporation, silanol condensation catalyst Neostan U-830: Nitto Kasei Co., Ltd., antioxidant Irganox 1010: BASF Japan, Inc., flame retardant (antimony trioxide): Twinkling Star・ Flame retardant (bromine-based flame retardant): Cytex 8010 Albemarle Japan Co., Ltd. ・ Flame retardant (melamine cyanurate): Mc20s Nesium): Magseeds S4, manufactured by Kamishima Chemical Industries, Ltd. ・ Flame retardant (aluminum hydroxide): MARTINAL OL-107ZO, manufactured by Albemarle Japan, Inc.

<Example 1>
(Preparation of flame retardant batch)
First, as shown in Table 1 below, the above materials were blended to prepare a flame retardant batch.
Specifically, a free radical generator (0.02 parts by mass) is dissolved in a silane compound (6 parts by mass), and a flame retardant in a plastic bag (20 parts by mass of antimony trioxide and bromine-based flame retardant). A total of 60 parts by mass of 20 parts by mass of the fuel and 20 parts by mass of melamine cyanurate) was impregnated. Next, when the internal temperature in the 3 L kneader reached 90 ° C., polyolefin (100 parts by mass of EVA) was added, and when the polyolefin was softened, a powdery flame retardant impregnated with a silane compound was added and kneaded. When the temperature reached 150 ° C., a silanol condensation catalyst (0.03 parts by mass) and an antioxidant (0.1 parts by mass) were added, and when the internal temperature reached 160 ° C., the material was taken out. Thereby, the flame retardant batch which a flame retardant (B) and a silanol condensation catalyst disperse | distribute in a silane graft | grafting polyolefin (A) was obtained. Then, the flame retardant batch was taken out, formed into a tape shape with an 8-inch roll, and pelletized with a square pelletizer. The reason why the silanol condensation catalyst was added immediately before the removal was to suppress the crosslinking reaction in the kneader, and the reason why the antioxidant was added immediately before the removal was to prevent the graft polymerization of the silane compound from being inhibited. It is.

(Preparation of silane batch)
Subsequently, a silane batch to be mixed with the flame retardant batch was prepared.
Specifically, using a 40 mm extruder, a polymer is introduced from a hopper, a solution in which a free radical generator is dissolved in a silane compound is injected with a liquid pump, a cylinder temperature of 200 ° C., a residence time in the extruder of 100 to 150 A silane graft polymer was prepared by extruding into a strand shape at a setting of seconds and graft-polymerizing a silane compound having a diameter of 2 to 3 mm with a pelletizer.
The polymer used was V5274 (EVA EVAFLEX: Mitsui-DuPont Polychemical Co., Ltd.), the silane compound was KBM-1003 (Shin-Etsu Chemical Co., Ltd.), and the free radical generator was Park Mill D (NOF Corporation). 4 parts by mass of the silane compound and 0.1 parts by mass of the free radical generator with respect to 100 parts by mass of the polymer.

(Production of electric wire)
Subsequently, a coating layer was formed using the flame retardant batch and the silane batch prepared above to produce an electric wire.
Specifically, flame retardant batch pellets and silane batch pellets are mixed in the proportions shown in Table 1, charged into a 20 mm extruder from a hopper, and retained in the extruder at a cylinder temperature of 180 ° C and a die temperature of 200 ° C. The time was set to 120 to 150 seconds, and the outer periphery of the conductor was extrusion coated so that the coating thickness was 0.4 mm. Thereafter, the conductor coated by extrusion was allowed to stand for 24 hours in an environment where moisture was present at a temperature of 80 ° C., and was crosslinked by silane to form an insulating layer, thereby producing an electric wire. As a conductor, a core wire having a diameter of 0.8 mm was used.

<Examples 2 to 11>
In Examples 2-4, as shown in Table 1, the electric wire was produced similarly to Example 1 except having changed the kind of flame retardant to be used and preparing the flame-retardant batch.
In Examples 5-11, as shown in Table 1, it was the same as Example 1 except that the flame retardant batch was prepared by changing the blending amount of each flame retardant so that the total amount of the flame retardant was 80 parts by mass. An electric wire was prepared.

<Examples 12 to 20>
As shown in Table 2 below, in each of Examples 12 to 14, the total amount of the flame retardant is 140 parts by mass, and in Examples 15 to 20, each of the flame retardant is 300 parts by mass. An electric wire was produced in the same manner as in Example 1 except that the flame retardant batch was prepared by changing the blending amount of the flame retardant.

<Examples 21 to 25>
In Examples 21 to 25, as shown in Table 3 below, a flame retardant batch similar to Examples 10, 14, and 17 was prepared, and the mixing ratio of the flame retardant batch and the silane batch was appropriately changed. An electric wire was produced in the same manner as in Example 1.

<Comparative Examples 1-9>
In Comparative Examples 1 to 9, a flame retardant batch, a silane batch, and a catalyst batch were prepared as follows, and an electric wire was produced by mixing them.
As shown in Table 4 below, the flame retardant batch melts and kneads the polyolefin, the flame retardant and the antioxidant without blending the silane compound and the free radical generator, and the flame retardant and the antioxidant are dispersed in the polyolefin. It was prepared as follows.
A silane batch was prepared as in Example 1.
The catalyst batch was prepared by kneading 99.9 parts by mass of polyolefin (EVA V5724) and 0.1 part by mass of silanol condensation catalyst (Neostan U-830), so that the catalyst-containing concentration was 0.1%. did.
And the electric wire was produced by mixing each batch by the ratio shown in following Table 4, and extruding.

<Comparative Examples 10-14>
In Comparative Examples 10 to 13, as shown in Table 5, electric wires were produced in the same manner as in Example 1 except that flame retardant batches were prepared using only two different flame retardants.
In Comparative Example 14, an electric wire was prepared in the same manner as in Example 1 except that the flame retardant batch was prepared by changing the blending amount of each flame retardant so that the total amount of the flame retardant was 350 parts by mass.

〔Evaluation method〕
Each produced electric wire was evaluated by the following method.

(Surface appearance)
About the surface of the insulating layer of the produced electric wire, the smoothness was touched and the presence or absence of granular protrusions was visually evaluated. In this example, a particularly good product with a smooth touch and no granular protrusions per 5 m of the wire is good, roughness is found by the touch, and 10 or more granular protrusions per 5 m of the electric wire are visually confirmed. Was evaluated as x, and ○ or higher was determined as acceptable.

(Mechanical properties)
The mechanical properties of the insulating layer were evaluated by the following tensile test. Specifically, an initial tensile test was performed on an insulating layer obtained by pulling the core wire out of the produced electric wire in an atmosphere of 23 ° C. (± 3 ° C.) and humidity 50% (± 10%). The tensile test is an average of n = 3, and the marked line is an evaluation at 50 mm. In this example, a strength of 10 MPa or more and an elongation of 200% or more was evaluated as ◯, and a strength of less than 10 MPa or an elongation of less than 200% was evaluated as x.

(Flame retardance)
The flame retardancy of the insulating layer was evaluated by the following two tests.
One performed the VFT test 10 times and compared the pass rate. In this example, if the pass rate was 50% or more, it was evaluated as having sufficient flame retardancy.
The other was conducted 10 times for the VW-1 test, and the pass rates were compared. In this example, if the pass rate was 50% or more, it was evaluated as having high flame retardancy.

〔Evaluation results〕
The evaluation results of each example and comparative example are shown in the respective tables.

  According to Examples 1 to 4, it was confirmed that there was no granular protrusion per 5 m of the electric wire with a smooth hand, and the insulating layer was excellent in surface smoothness. It was also confirmed that both the strength and elongation were high and the mechanical properties were excellent because the aggregation of the flame retardant was suppressed. Furthermore, the pass rate of the VFT test was 70%, and it was confirmed that it has sufficient flame retardancy. That is, it was confirmed that the insulating layer of Example 1 was excellent in surface smoothness, mechanical properties, and flame retardancy.

  In Examples 5 to 7, the total amount of the flame retardant was larger than those in Examples 1 to 4, and thus the pass rate in the VFT test was 100%, and it was confirmed that the flame retardancy was higher.

  In Examples 8 to 11, although the total amount of the flame retardant is the same as in Examples 5 to 7, the pass rate in the VW-1 test is 50% to 70%, and the pass rate of VW-1 is 50 It was confirmed that the flame retardancy is higher than those of Examples 5 to 7 which are less than%. This is presumably due to the difference in the combination of flame retardants. That is, in Examples 8 to 11, a flame retardant (antimony compound, bromine flame retardant and melamine flame retardant) that exhibits an oxygen asphyxia effect, and a flame retardant (magnesium hydroxide and aluminum hydroxide) that exhibits an endothermic effect; Therefore, it is presumed that flame retardancy higher than those of Examples 5 to 7 which were not used together could be obtained.

  According to Examples 12 to 20, by setting the total amount of the flame retardant to 140 parts by mass or more, it becomes possible to set the pass rate in the VW-1 test to 100% and to realize high flame retardancy. It was done.

  According to Examples 21 to 25, the mixing ratio of the flame retardant batch and the silane batch may be in the range of 99: 1 to 20:80, but the pass rate in the VW-1 test is 100%. In order to obtain such a high flame retardance, it was confirmed that it should be in the range of 99: 1 to 30:70.

  According to Comparative Examples 1-8, because the flame retardant batch was not configured to disperse the flame retardant in the silane grafted polyolefin, the flame retardant could not be uniformly dispersed when mixed with the silane batch. The pass rate was less than 50%, and sufficient flame retardancy could not be ensured.

  In Comparative Example 9, since the flame retardant was blended in a large amount so that the total amount was 250 parts by mass, the pass rate in the VFT test was 50%, and sufficient flame retardancy was obtained. However, the aggregation of the flame retardant not only deteriorated the surface smoothness of the insulating layer and deteriorated the surface smoothness, but also failed to obtain desired mechanical properties.

  In Comparative Examples 10 to 13, although the total amount of the flame retardant was 80 parts by mass as in Example 5, the pass rate of the VFT test was less than 50%, and sufficient flame retardancy was not obtained. This is presumed that, in Comparative Examples 10 to 13, two types of flame retardants were used, and the respective flame retardants aggregated together, resulting in uneven dispersion.

  In Comparative Example 14, a flame retardant batch was prepared so as to uniformly disperse the flame retardant. However, since the total amount of the flame retardant was excessively 350 parts by mass, high flame retardancy was obtained, but the flame retardant It was confirmed that the surface smoothness and mechanical properties were deteriorated without sufficiently suppressing aggregation.

  As described above, according to the flame retardant batch of the present invention, it is possible to uniformly disperse while increasing the blending amount of the flame retardant, so that the surface smoothness and mechanical properties due to aggregation can be obtained while obtaining high flame retardancy. Decrease can be suppressed, and these can be obtained at a high level.

<Preferred embodiment of the present invention>
Hereinafter, preferred embodiments of the present invention will be additionally described.

[Appendix 1]
According to one aspect of the invention,
A flame retardant batch for blending with a silane batch containing a silane graft polymer in which a silane compound is graft-polymerized to a polymer to impart flame retardancy,
A silane-grafted polyolefin (A) obtained by graft-polymerizing a silane compound to the polyolefin (a) in the presence of a free radical generator;
An antimony compound, a brominated flame retardant, a melamine flame retardant, a flame retardant containing at least three of magnesium hydroxide and aluminum hydroxide (B), and
There is provided a flame retardant batch containing the flame retardant (B) in an amount of 60 parts by mass to 300 parts by mass with respect to 100 parts by mass of the polyolefin (a).

[Appendix 2]
In the flame retardant batch of appendix 1, preferably,
The flame retardant (B) includes the antimony compound and the brominated flame retardant (b1), the brominated flame retardant and the melamine flame retardant (b2), and the antimony compound, the brominated flame retardant and the melamine. A combination of any one of the series flame retardants (b3) and at least one of magnesium hydroxide and aluminum hydroxide.

[Appendix 3]
In the flame retardant batch of Appendix 1 or 2, preferably,
The polyolefin (a) contains an ethylene-vinyl acetate copolymer.

[Appendix 4]
In the flame retardant batch according to any one of appendices 1 to 3, preferably,
A silane crosslinking catalyst (C) is further contained.

[Appendix 5]
According to another aspect of the invention,
A polyolefin (a), a silane compound, a free radical generator, a flame retardant (B) containing at least three of an antimony compound, a brominated flame retardant, a melamine flame retardant, magnesium hydroxide and aluminum hydroxide. While mixing, the polyolefin (a) is graft-polymerized with the silane compound in the presence of the free radical generator to form the silane-grafted polyolefin (A). A flame retardant batch preparation step to obtain a flame retardant batch by dispersing
An extrusion step of mixing the flame retardant batch and a silane batch containing a silane graft polymer in which a silane compound is graft-polymerized to the polymer, and extruding the mixture so as to cover the outer periphery of the conductor;
There is provided a method of manufacturing an electric wire / cable having a crosslinking step of forming a coating layer by silane crosslinking the molded body.

[Appendix 6]
In the method for manufacturing an electric wire / cable of appendix 5, preferably,
In the extrusion step, the flame retardant batch and the silane batch are mixed within a range of 99: 1 to 20:80.

[Appendix 7]
According to yet another aspect of the invention,
Comprising a conductor and a coating layer disposed on the outer periphery of the conductor;
The coating layer is obtained by crosslinking a mixture containing a silane batch containing a silane graft polymer obtained by graft polymerization of a silane compound to a polymer and a flame retardant batch,
The flame retardant batch is
A silane-grafted polyolefin (A) obtained by graft-polymerizing a silane compound to the polyolefin (a) in the presence of a free radical generator;
An antimony compound, a brominated flame retardant, a melamine flame retardant, a flame retardant containing at least three of magnesium hydroxide and aluminum hydroxide (B), and
An electric wire / cable containing the flame retardant (B) so as to be 60 parts by mass or more and 300 parts by mass or less with respect to 100 parts by mass of the polyolefin (a) is provided.

[Appendix 8]
In the wire / cable of appendix 7,
The tensile strength is 10 MPa or more and the elongation is 200% or more.

DESCRIPTION OF SYMBOLS 10 Electric wire 11 Conductor 12 Insulating layer 20 Cable 21 Conductor 22 Insulating layer 23 Electric wire 24 Holding tape 25 Sheath

Claims (8)

A flame retardant batch for blending with a silane batch containing a silane graft polymer in which a silane compound is graft-polymerized to a polymer to impart flame retardancy,
A silane-grafted polyolefin (A) obtained by graft-polymerizing a silane compound to the polyolefin (a) in the presence of a free radical generator;
An antimony compound, a brominated flame retardant, a melamine flame retardant, a flame retardant containing at least three of magnesium hydroxide and aluminum hydroxide (B), and
A flame retardant batch containing the flame retardant (B) so as to be 60 parts by mass or more and 300 parts by mass or less with respect to 100 parts by mass of the polyolefin (a).   The flame retardant (B) includes the antimony compound and the brominated flame retardant (b1), the brominated flame retardant and the melamine flame retardant (b2), and the antimony compound, the brominated flame retardant and the melamine. The flame retardant batch according to claim 1, comprising a combination of any one of the system flame retardants (b3) and at least one of magnesium hydroxide and aluminum hydroxide.   The flame retardant batch according to claim 1 or 2, wherein the polyolefin (a) contains an ethylene-vinyl acetate copolymer.   The flame retardant batch according to any one of claims 1 to 3, further comprising a silane crosslinking catalyst (C). A polyolefin (a), a silane compound, a free radical generator, a flame retardant (B) containing at least three of an antimony compound, a brominated flame retardant, a melamine flame retardant, magnesium hydroxide and aluminum hydroxide. While mixing, the polyolefin (a) is graft-polymerized with the silane compound in the presence of the free radical generator to form the silane-grafted polyolefin (A). A flame retardant batch preparation step to obtain a flame retardant batch by dispersing
An extrusion step of mixing the flame retardant batch and a silane batch containing a silane graft polymer in which a silane compound is graft-polymerized to the polymer, and extruding the mixture so as to cover the outer periphery of the conductor;
And a crosslinking step of forming a coating layer by crosslinking the molded body with silane.   The method for producing an electric wire / cable according to claim 5, wherein in the extrusion step, the flame retardant batch and the silane batch are mixed within a range of 99: 1 to 20:80. Comprising a conductor and a coating layer disposed on the outer periphery of the conductor;
The coating layer is obtained by crosslinking a mixture containing a silane batch containing a silane graft polymer obtained by graft polymerization of a silane compound to a polymer and a flame retardant batch,
The flame retardant batch is
A silane-grafted polyolefin (A) obtained by graft-polymerizing a silane compound to the polyolefin (a) in the presence of a free radical generator;
An antimony compound, a brominated flame retardant, a melamine flame retardant, a flame retardant containing at least three of magnesium hydroxide and aluminum hydroxide (B), and
The electric wire and cable which contain the said flame retardant (B) so that it may become 60 to 300 mass parts with respect to 100 mass parts of said polyolefin (a).   The electric wire / cable according to claim 7, wherein the tensile strength is 10 MPa or more and the elongation is 200% or more.

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