JP2017133032A - Vinyl chloride resin composition, insulated wire prepared using the same, and method of producing insulated wire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vinyl chloride resin composition having excellent flame retardancy as well as excellent electric characteristics, thermal stability, cold resistance and moldability, and provide an insulated wire prepared using the same.SOLUTION: A vinyl chloride resin composition comprises polyvinyl chloride resin, plasticizer, amorphous silica, hydrotalcite and baked clay, and is free from metalhydroxide.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a vinyl chloride resin composition, an insulated wire using the same, and a method for producing an insulated wire.

  Insulated wires are used for internal wiring of electronic devices. The insulated wire includes a conductor and an insulating coating provided so as to cover the outer periphery of the conductor, and the conductor is electrically insulated from the outside.

  Insulated wires used for internal wiring of electronic devices are required to have flame retardance so that fire does not burn and spread through the insulated wires in the event of a fire accident of electronic devices. For example, the insulated wire is required to have a high flame retardance so as to pass a vertical combustion test (VW-1 test) of UL758 standard in the United States.

  A vinyl chloride resin composition containing a vinyl chloride resin is widely used as a forming material for the insulation coating of such insulated wires. Vinyl chloride resin contains chlorine, which is a halogen, in its chemical structure, and is excellent in flame retardancy.

  Since vinyl chloride resin is generally hard, when used as a material for forming an insulating coating that requires flexibility, a large amount of plasticizer is added to soften the resin. However, the plasticizer is flammable and reduces the flame retardancy of the vinyl chloride resin composition. For this reason, in the vinyl chloride resin composition containing a large amount of plasticizer, it becomes difficult to obtain the flame retardancy inherent to the vinyl chloride resin.

  Therefore, a flame retardant is added to the vinyl chloride resin composition containing a plasticizer in order to improve the flame retardancy that is lowered by the plasticizer. Conventionally, antimony compounds have been used as flame retardants, but antimony compounds have a negative effect on the environment and the human body, and are rare and tend to increase in price. Therefore, in recent years, for example, metal hydroxides such as aluminum hydroxide and magnesium hydroxide have been used as flame retardants to replace antimony compounds.

  For example, as a vinyl chloride resin composition containing no harmful antimony compound, 8 to 22 parts by mass of aluminum hydroxide and / or magnesium hydroxide with respect to 100 parts by mass of vinyl chloride resin, and a lead-free stabilizer. What was added is disclosed (for example, refer patent document 1).

JP 2011-26427 A

  However, according to the knowledge of the present inventor, the metal hydroxide improves the flame retardancy of the vinyl chloride resin composition, but may reduce its electrical properties, thermal stability, cold resistance and moldability. . In particular, as in Patent Document 1, when a large amount (8 to 22 parts by mass) of metal hydroxide is contained, there is a problem in that various characteristics of the vinyl chloride resin composition are greatly reduced.

  The present invention has been made in view of such problems, and is a vinyl chloride resin composition excellent in electrical properties, thermal stability, cold resistance and moldability as well as flame retardancy, and insulation using the same. The purpose is to provide electric wires.

  According to the first aspect of the present invention, a vinyl chloride resin containing a vinyl chloride resin, a plasticizer, amorphous silica, hydrotalcite, and calcined clay, and containing no metal hydroxide. A composition is provided.

According to a second aspect of the invention,
An insulated wire comprising a conductor and an insulating coating formed from the vinyl chloride resin composition of the first aspect on the outer periphery of the conductor is provided.

According to a third aspect of the invention,
The insulated wire of the 2nd aspect in which the said insulation coating is bridge | crosslinked is provided.

According to a fourth aspect of the invention,
There is provided a method for producing an insulated wire, comprising a step of extrusion-coating the vinyl chloride resin composition of the first aspect on the outer periphery of a conductor to form an insulation coating.

According to a fifth aspect of the present invention,
A method for producing an insulated wire according to a fourth aspect, further comprising a step of crosslinking the insulating coating is provided.

  According to the present invention, a vinyl chloride resin composition excellent in electrical properties, thermal stability, cold resistance and moldability as well as flame retardancy, and an insulated wire using the same can be obtained.

It is sectional drawing of the insulated wire which concerns on one Embodiment of this invention.

<Knowledge obtained by the present inventor>
Prior to the description of the reference embodiment and the embodiment of the present invention, the knowledge obtained by the present inventor will be described.

  As described above, metal hydroxides such as aluminum hydroxide and magnesium hydroxide can improve the flame retardancy of the vinyl chloride resin composition. However, the metal hydroxide may reduce the electrical properties, thermal stability, cold resistance and moldability of the vinyl chloride resin composition. Therefore, in the insulating coating formed from the vinyl chloride resin composition containing a large amount of metal hydroxide, the following problems (1) to (4) occur.

(1) Since aluminum hydroxide has a low volume resistivity, the volume resistivity of the vinyl chloride resin composition is reduced and the electrical properties (electrical insulation) of the insulation coating are reduced. Magnesium hydroxide hydrolyzes the plasticizer contained in the vinyl chloride resin composition, thereby reducing the electrical properties of the insulating coating, similar to aluminum hydroxide.

(2) Since aluminum hydroxide reduces the thermal stability of the vinyl chloride resin composition, the insulating coating tends to be thermally deteriorated.

(3) Since metal hydroxides such as aluminum hydroxide lower the cold resistance of the vinyl chloride resin composition, the insulating coating becomes brittle and prone to cracking when exposed to low temperatures.

(4) When a vinyl hydroxide resin composition is extruded while being sheared and molded into an insulating coating, the metal hydroxide such as aluminum hydroxide promotes shearing heat generation of the resin and causes foaming of the resin. When the resin is foamed, the appearance of the insulation coating to be molded is deteriorated. In addition, aluminum hydroxide or the like becomes a factor that causes die scum at the die outlet when the vinyl chloride resin composition is extruded by a die and molded into an insulating coating. When die scum occurs, the thickness of the insulation coating to be molded may vary (so-called outer diameter error occurs). The occurrence of such resin foaming and die scum becomes more remarkable as the speed at which the vinyl chloride resin composition is extruded (extrusion speed) is increased. As described above, aluminum hydroxide or the like deteriorates the moldability of the vinyl chloride resin composition, thereby causing an appearance defect or an outer diameter error of the insulating coating.

  In order to suppress the deterioration of the properties of the vinyl chloride resin composition due to the metal hydroxide, it is conceivable to reduce the content of the metal hydroxide. Therefore, the present inventor reduces the amount of metal hydroxide to be contained in the vinyl chloride resin composition in order to reduce the amount of metal hydroxide to be contained while maintaining high flame retardance that passes the VW-1 test. We investigated other flame retardant compounds that can compensate for the decrease in flame retardant properties caused by. As a result, they have found that a combination of amorphous silica and at least one selected from hydrotalcite and calcined clay is good. Since these compounds each have flame retardancy, they can be used in place of metal hydroxides. And according to the combination of these compounds, a part or all of metal hydroxide can be replaced. That is, the content of the metal hydroxide can be reduced or zero. As a result, while maintaining the same flame retardancy as when only a large amount of metal hydroxide is used, it is possible to suppress deterioration of electrical properties, thermal stability, cold resistance and moldability due to metal hydroxide. it can.

  The present invention has been made based on the above findings.

[Reference form of the present invention]
In the present invention, as described above, a part or all of the metal hydroxide can be replaced by amorphous silica and any one of hydrotalcite and calcined clay. In this reference embodiment, a case where a part of the metal hydroxide is replaced will be described. Specifically, a case where a metal hydroxide, amorphous silica, and one of hydrotalcite and calcined clay are contained will be described. In the following, metal hydroxide, amorphous silica, hydrotalcite and calcined clay are respectively represented by (A) metal hydroxide, (B) amorphous silica, (C1) hydrotalcite and (C2). This will be described as a fired clay.

<Vinyl chloride resin composition>
The vinyl chloride resin composition of the present embodiment comprises a vinyl chloride resin, a plasticizer, (A) metal hydroxide, (B) amorphous silica, (C1) hydrotalcite, and (C2) calcined clay. Any one of these.

  Hereinafter, each component will be specifically described.

(Vinyl chloride resin)
Vinyl chloride resin is a base resin. The vinyl chloride resin is not particularly limited, and a vinyl chloride homopolymer or a copolymer of vinyl chloride and other copolymerizable monomers, such as a vinyl chloride-vinyl acetate copolymer, can be used. . Moreover, you may mix and use ethylene-vinyl acetate copolymer, a chlorinated polyethylene, etc. for these resin as needed. The vinyl chloride resin preferably has an average degree of polymerization of 1300 or more and 2500 or less, and more preferably 1500 or more and 2000 or less, from the viewpoints of thermal stability, cold resistance and molding processability.

(Plasticizer)
It does not specifically limit as a plasticizer, A conventionally well-known plasticizer can be used. Among the plasticizers, trimellitic acid-based plasticizers are preferable, and for example, trimellitic acid tri-2-ethylhexyl, trimellitic acid tri-normal alkyl, trimellitic acid triisodecyl, and the like can be used. From the viewpoint of thermal stability and cold resistance, trinormal alkyl trimellitic acid is more preferable. The trimellitic alkyl trimellitic acid preferably contains an alkyl group having 8 carbon atoms as a main component, and may contain an alkyl group having 10 carbon atoms as a subcomponent.

  The content of the plasticizer can be appropriately changed according to the flexibility required for the insulating coating. However, if the plasticizer content is too small, the insulating coating may crack due to brittleness when the vinyl chloride resin composition is formed on the insulating coating. On the other hand, when the content of the plasticizer is too large, the plasticizer is eluted from the vinyl chloride resin composition, and the insulating coating becomes sticky. For this reason, content of a plasticizer is good in it being 35 mass parts or more and 60 mass parts or less with respect to 100 mass parts of vinyl chloride resin, and it is better in it being 40 mass parts or more and 55 mass parts or less.

((A) metal hydroxide)
(A) A metal hydroxide improves the flame retardance of a vinyl chloride resin composition. (A) The metal hydroxide is dehydrated by heating, and the temperature of the vinyl chloride resin is reduced by the released moisture (endothermic reaction) to suppress the combustion.

  (A) It does not specifically limit as a metal hydroxide, For example, aluminum hydroxide, magnesium hydroxide, etc. can be used. These may be used alone or in combination of two or more. Magnesium hydroxide has a higher dehydration temperature than aluminum hydroxide, but may cause hydrolysis and coloring of the plasticizer in the vinyl chloride resin composition. For this reason, it is preferable to use only aluminum hydroxide as metal hydroxide (A) without using magnesium hydroxide. Thereby, the electrical property and molding processability of the vinyl chloride resin composition can be improved.

  (A) Although the average particle diameter of a metal hydroxide is not specifically limited, It is preferable that it is 2 micrometers or less from a dispersible viewpoint. Moreover, it is preferable that (A) metal hydroxide is not surface-treated.

((B) amorphous silica)
(B) Amorphous silica is amorphous particulate silica. Amorphous fine particle silica is obtained, for example, by reducing silica to a gas and oxidizing it in its vapor phase. Amorphous particulate silica, for example, a substantially spherical primary particle shape, an average particle diameter of 0.1μm or more 0.2.mu. m or less. In addition, the amorphous fine particle silica has few active hydrogen groups on the surface. Therefore, amorphous fine particle silica is easily dispersed in the vinyl chloride resin composition as compared with conventional fine particle silica. The amorphous fine particle silica can be improved in flame retardancy by being dispersed in the vinyl chloride resin composition. This point will be specifically described below.

  The amorphous fine particle silica can be uniformly dispersed in the vinyl chloride resin composition without agglomeration. When the vinyl chloride resin composition begins to burn (in the early stage of combustion), the amorphous fine particle silica is uniformly arranged on the resin surface to form a hard solidified layer (so-called char). According to the solidified layer, oxygen can be blocked and combustion of the vinyl chloride resin composition can be suppressed. In addition, the amorphous fine particle silica can suppress the diffusion of the combustion product and suppress the spread of the fire by reducing the gasified foam diameter starting from the silica in the vinyl chloride resin composition. Thus, according to the amorphous fine particle silica, the vinyl chloride resin composition can be imparted with flame retardancy equal to or higher than that of nano silica.

  In addition, even when the amorphous fine particle silica is highly filled in the vinyl chloride resin composition, a decrease in molding processability of the vinyl chloride resin composition due to agglomeration and a decrease in elongation of the insulating coating are small.

((C1) Hydrotalcite)
(C1) Hydrotalcite is represented by, for example, the composition formula Mg ₆ Al ₂ (OH) ₁₆ CO ₃ .4H ₂ O, has a layered structure containing magnesium and aluminum, and carbonate ions (CO ₃ ² between the layers). ^-) is a compound containing. (C1) Hydrotalcite has anion exchange properties in the acidic region, and thus can improve the flame retardancy and thermal stability of the vinyl chloride resin composition. This point will be specifically described below.

(C1) hydrotalcites, the carbonate ion chemical structure (CO ₃ ^2-), chlorine ions hydrogen chloride generated by thermal degradation of the vinyl chloride resin (Cl ^-) was replaced (ion exchange), chlorine ions It can be trapped in the crystal structure. By this ion exchange, (C1) hydrotalcite becomes a chlorine ion type hydrotalcite compound. This compound has the property that it captures chlorine ions in the chemical structure and does not desorb them until a temperature of about 400 ° C. is reached. Therefore, (C1) hydrotalcite can improve the thermal stability of the vinyl chloride resin by capturing hydrogen chloride desorbed from the chemical structure of the vinyl chloride resin and suppressing its thermal degradation. In addition, (C1) hydrotalcite improves the thermal stability, increases the thermal degradation start temperature of the vinyl chloride resin, and promotes its carbonization (burning shell), thereby improving the flame retardancy of the vinyl chloride resin. Improve.

((C2) calcined clay)
(C2) The fired clay imparts electrical characteristics and flame retardancy to the vinyl chloride resin composition. (C2) The calcined clay is, for example, one type of kaolin clay and is obtained by calcining wet kaolin (chemical formula: Al ₂ O ₃ .2SiO ₂ .2H ₂ O). (C2) In the fired clay, crystal water is released by firing, and the original crystal structure is destroyed. With this structure, the (C2) calcined clay has higher activity than other kaolins (wet kaolin, dry kaolin, etc.), and easily adsorbs and fixes free ions. Thereby, (C2) baked clay can improve the electrical property (electrical insulation) of a vinyl chloride resin more. In addition, since the (C2) fired clay has a porous structure, it takes in low-molecular organic components and contributes to the flame retardancy of the vinyl chloride resin.

(Composition of each component)
As described above, in the vinyl chloride resin composition, for example, in order to obtain high flame retardancy that passes the above-described VW-1 test, when only (A) a metal hydroxide is used, its content is set to 8 It is necessary to make it not less than part by mass. However, in this case, various properties of the vinyl chloride resin composition are degraded by a large amount of metal hydroxide. On the other hand, in this reference embodiment, (B) amorphous silica and (C1) at least one of hydrotalcite and (C2) calcined clay are replaced with a part of (A) metal hydroxide. Thereby, content of (A) metal hydroxide can be reduced to less than 8 mass parts. In particular, it has been found by the present inventor that when the content of the metal hydroxide is 7 parts by mass or less, the deterioration of various properties of the vinyl chloride resin composition due to the metal hydroxide can be suppressed. There are the following three cases in the combination of the component (A) to the component (C2).
(1): (A) metal hydroxide + (B) amorphous silica + (C1) hydrotalcite (2): (A) metal hydroxide + (B) amorphous silica + (C2) calcination Clay (3): (A) metal hydroxide + (B) amorphous silica + (C1) hydrotalcite + (C2) calcined clay

  Here, the mixing | blending of each component is demonstrated about each in the case of said (1)-(3). In addition, in this reference form, mixing | blending (content of each component) can be changed suitably, The following is the example.

In the case of (1), three components of (A) metal hydroxide, (B) amorphous silica, and (C1) hydrotalcite are used. In this case, the contents of (B) amorphous silica and (C1) hydrotalcite are preferably set in the following ranges with respect to 100 parts by mass of the vinyl chloride resin. “˜” indicates a range of “a predetermined numerical value or more and a predetermined numerical value or less”.
(B) Amorphous silica: 4 to 15 parts by mass, preferably 4 to 10 parts by mass (C1) Hydrotalcite: 5 to 30 parts by mass, preferably 5 to 25 parts by mass Part

  By setting the content of (B) amorphous silica and (C1) hydrotalcite within the above range, the content of (A) metal hydroxide can be 7 parts by mass or less. Preferably, the content of (A) the metal hydroxide can be 0.1 parts by mass or more and 6 parts by mass or less. In addition, when using 2 or more types together as (A) metal hydroxide, it uses so that the sum may become the said range.

In the case of (2), three components of (A) metal hydroxide, (B) amorphous silica, and (C2) calcined clay are used. In this case, the content of (B) amorphous silica and (C2) calcined clay is preferably in the following range with respect to 100 parts by mass of the vinyl chloride resin.
(B) Amorphous silica: 4 to 15 parts by mass, preferably 4 to 10 parts by mass (C2) Firing clay: 4 to 15 parts by mass, preferably 5 to 10 parts by mass

  By setting the content of (B) amorphous silica and (C2) calcined clay within the above range, the content of (A) metal hydroxide can be 7 parts by mass or less. Preferably, the content of (A) the metal hydroxide can be 0.1 parts by mass or more and 6 parts by mass or less. In the case of (2), when (B) amorphous silica and (C2) calcined clay are used in combination, flame retardancy can be further improved due to a synergistic effect as compared with the case where each is used alone. For this reason, even if it is a case where content of 3 components is reduced, desired flame retardance can be acquired.

In the case of (3), four components of (A) metal hydroxide, (B) amorphous silica, (C1) hydrotalcite, and (C2) calcined clay are used. In this case, the contents of (B) amorphous silica, (C1) hydrotalcite, and (C2) calcined clay may be in the following ranges with respect to 100 parts by mass of the vinyl chloride resin.
(B) Amorphous silica: 4 to 15 parts by mass, preferably 4 to 10 parts by mass (C1) Hydrotalcite: 5 to 30 parts by mass, preferably 5 to 25 parts by mass Parts / (C2) calcined clay: 4 to 15 parts by mass, preferably 5 to 10 parts by mass

  By setting the content of (B) amorphous silica, (C1) hydrotalcite, and (C2) calcined clay within the above range, the content of (A) metal hydroxide is 7 parts by mass or less. be able to. Preferably, the content of (A) the metal hydroxide can be 0.1 parts by mass or more and 6 parts by mass or less. In the case of (3), as in the case of (2), (B) amorphous silica and (C2) calcined clay are used together. The sex can be further improved. For this reason, even if it is a case where content of 4 components is reduced, desired flame retardance can be acquired. For example, the content of any component can be reduced and adjusted so as to reduce the content of high-cost (C1) hydrotalcite.

  Thus, according to this embodiment, (A) metal hydroxide is obtained by using (B) amorphous silica and any one of (C1) hydrotalcite and (C2) calcined clay. The content of the product can be reduced.

(Other additives)
In this reference form, in addition to the above components, a stabilizer may be further used as necessary. The stabilizer is not limited as long as it is a lead-free stabilizer that does not contain lead.

  An inorganic filler may be further used. As the inorganic filler, for example, calcium carbonate or talc can be used.

  In addition, when the insulating coating is crosslinked, a crosslinking agent and a crosslinking aid may be used. As the crosslinking agent, an organic peroxide, a silane compound, or the like can be used. Further, as a crosslinking aid, trimethylolpropane trimethacrylate, dipentaerythritol hexaacrylate, or the like can be used. The content of the crosslinking aid is not particularly limited, but if it is too small, crosslinking is insufficient, and if it is too large, crosslinking proceeds during the molding process. For this reason, it is good for content of a crosslinking adjuvant to be 2 to 20 mass parts with respect to 100 mass parts of vinyl chloride resins. With such a content, the degree of crosslinking of the insulating coating when crosslinked is 40% or more and 65% or less, preferably 49% or more and 60% or less in terms of gel fraction.

  Moreover, you may contain 1 type (s) or 2 or more types, as needed, a ultraviolet absorber, a light stabilizer, a lubricant, a coloring agent, a processability improving agent, another modifier. A conventionally well-known thing can be used for these and the content can also be suitably changed according to a use.

  In addition, the vinyl chloride resin composition of this reference form includes the above-described vinyl chloride resin, a plasticizer, (A) a metal hydroxide, (B) amorphous silica, (C1) hydrotalcite, and (C2 ) It is obtained by mixing at least one of the calcined clay and, if necessary, other additives such as a crosslinking aid and kneading while heating. The kneading conditions and the order of adding each component are not particularly limited, and are the same as those conventionally known. The kneading can be performed using a mixing roll, a Banbury mixer, a single-screw or twin-screw extruder, and the like. Moreover, the heating temperature at the time of kneading shall be 170 degreeC or more and 200 degrees C or less, for example.

<Insulated wire>
Next, the insulated wire concerning one Embodiment of this invention is demonstrated using FIG. FIG. 1 shows a cross-sectional view of an insulated wire 1 according to an embodiment of the present invention.

  As shown in FIG. 1, the insulated wire 1 includes a conductor 10 and an insulating coating 11 provided so as to cover the outer periphery of the conductor 10. The insulating coating 11 is formed from the above-described vinyl chloride resin composition.

  The conductor 10 is not particularly limited, and a commonly used metal wire such as a copper wire or a copper alloy wire, an aluminum wire, a gold wire, a silver wire, or the like can be used. Moreover, you may use what gave metal plating, such as tin and nickel, to the outer periphery of a metal wire. Further, a collective stranded conductor obtained by twisting metal wires can be used. The conductor diameter of the conductor 10 is not specifically limited, For example, it can be 0.15 mm or more and 7 mm or less.

  The insulating coating 11 is formed by extrusion coating the vinyl chloride resin composition of the embodiment on the outer periphery of the conductor 10. The thickness of the insulating coating 11 is not particularly limited, and can be, for example, 0.1 mm or more and 3 mm or less. The insulating coating 11 is preferably cross-linked from the viewpoint of improving mechanical properties. This crosslinking method is not particularly limited, and conventionally known methods such as organic peroxide crosslinking, silane crosslinking, and radiation crosslinking can be used. Among these, radiation crosslinking using an electron beam is preferable from the viewpoint of management and cost.

<Insulated wire manufacturing method>
The above-described insulated wire 1 can be manufactured by a conventionally known method. The manufacturing method of the insulated wire 1 includes, for example, a step of forming the insulating coating 11 by extrusion-coating the above-described vinyl chloride resin composition on the outer periphery of the conductor 10 and a step of crosslinking the insulating coating 11. Specifically, the insulating coating 11 is formed by running the conductor 10 at a predetermined linear velocity (for example, 400 m / min) and extrusion coating the vinyl chloride resin composition on the outer periphery thereof. Thereafter, the insulating coating 11 is cross-linked by irradiating the insulating coating 11 with an electron beam or the like. Thereby, the insulated wire 1 of this embodiment is obtained. In this embodiment, since (A) a vinyl chloride resin composition that does not contain a metal hydroxide and has excellent moldability is used, it is possible to suppress foaming due to shearing heat generation and the occurrence of die scum, and high-speed extrusion is possible. It is. That is, the production efficiency of the insulated wire 1 can be improved.

  In addition, although this embodiment demonstrated the case where a vinyl chloride resin composition was directly extrusion-coated on the outer periphery of a conductor and an insulating coating was formed as an insulating layer, this invention is not limited to this. For example, extrusion coating may be performed on the outer periphery of a normal insulated wire to form an insulating coating as a sheath. Moreover, although the case where the conductor 10 is a single core wire is shown in FIG. 1, this invention is not limited to this, A multi-core stranded wire may be sufficient. Moreover, the cross-sectional shape of the conductor 10 is not limited to a round shape, and may be a rectangular shape.

<Effects of Reference Embodiment of the Present Invention>
According to the present embodiment, one or more effects shown below are exhibited.

(A) According to this embodiment, the vinyl chloride resin composition comprises a vinyl chloride resin, a plasticizer, (A) a metal hydroxide, (B) amorphous silica, and (C1) hydrotalcite. And (C2) at least one of the calcined clay. Each of (B) amorphous silica, (C1) hydrotalcite and (C2) calcined clay is used in place of (A) metal hydroxide to impart flame retardancy to the vinyl chloride resin composition. Can do. And according to the combination of these compounds, even if it is a case where the content of (A) metal hydroxide is reduced by replacing part of (A) metal hydroxide, (A) metal hydroxide It is possible to maintain the same flame retardance as when only a large amount of material is used. Thereby, for example, the insulation coating has such a high flame retardance that passes the vertical combustion test (VW-1 test) of UL758 standard.

(B) According to the present embodiment, the reduction in the electrical properties of the vinyl chloride resin composition can be suppressed by reducing the content of (A) the metal hydroxide. Thereby, for example, the insulating coating has a high breakdown voltage of 15 kV or more in the initial state before thermal degradation.

(C) According to the present embodiment, it is possible to suppress a decrease in the thermal stability of the vinyl chloride resin composition by reducing the content of (A) the metal hydroxide. Thereby, the fall of the electrical property and tensile elongation by the heat deterioration of a vinyl chloride resin composition can be suppressed. For example, the insulation coating has a ratio B / A between the breakdown voltage A in the initial state before thermal degradation and the breakdown voltage B after standing at 136 ° C. for 168 hours of 0.9 or more, and the electrical characteristics due to thermal degradation The decrease is suppressed. In addition, the insulation coating has a decrease rate of the absolute value of tensile elongation of 50% or less when exposed to a high temperature environment of 150 ° C. for 500 hours, and the decrease in tensile elongation due to thermal deterioration is suppressed.

(D) According to the present embodiment, it is possible to suppress a decrease in cold resistance of the vinyl chloride resin composition by reducing the content of (A) the metal hydroxide. Thereby, for example, even when the insulating coating is exposed to an environment of −35 ° C. for 1 hour, it is difficult to become brittle and cracks are hardly generated.

(E) According to the present embodiment, the moldability of the vinyl chloride resin composition can be improved by reducing the content of (A) the metal hydroxide. For this reason, the vinyl chloride resin composition can be extruded at high speed. That is, even when the vinyl chloride resin composition is extruded at a high speed, for example, with a linear velocity of 400 m / min, foaming in the vinyl chloride resin composition can be suppressed, and an insulating coating having a good appearance can be obtained. it can. Furthermore, since the occurrence of die scum in the vinyl chloride resin composition can be suppressed, an insulating coating with little variation in thickness (outer diameter error) can be obtained.

(F) According to this embodiment, the content of (A) metal hydroxide is preferably 7 parts by mass or less with respect to 100 parts by mass of the vinyl chloride resin. Thereby, in a vinyl chloride resin composition, the fall of the various characteristics by (A) metal hydroxide can further be suppressed.

(G) According to the present embodiment, it is preferable to contain both (C1) hydrotalcite and (C2) calcined clay. Thereby, the flame retardance of a vinyl chloride resin composition can be improved more.

(H) According to this reference embodiment, the vinyl chloride resin composition is substantially free of harmful antimony compounds and lead-based stabilizers. Thereby, environmental load can be reduced.

(I) According to the present embodiment, for example, the insulating coating 11 of the insulated wire 1 having the configuration shown in FIG. 1 is formed using the above-described vinyl chloride resin composition. According to such an insulated wire, since it is provided with an insulating coating having the effects (a) to (h) above, for example, high temperatures in electrical equipment such as a dryer, rice cooker, transformer outlet, lighting fixture, and air conditioner. It can be used for wiring of parts.

(J) According to the present embodiment, the insulating coating 11 is preferably cross-linked. The cross-linking can further improve the mechanical properties of the insulating coating.

(K) According to this reference embodiment, the vinyl chloride resin composition is excellent in molding processability, and can be extruded at a high speed. Thereby, formation of the insulation coating 11 can be speeded up and the productivity of the insulated wire 1 can be improved.

Embodiment of the present invention
Next, an embodiment of the present invention will be described. However, only differences from the above-described reference embodiment will be described here.

  In the above-described reference embodiment, (A) the case where a part of the metal hydroxide is replaced has been described, but the present invention is not limited to this. In the present invention, (B) amorphous silica, (C1) hydrotalcite, and (C2) calcined clay can replace (A) all of the metal hydroxide. That is, in the vinyl chloride resin composition, flame retardancy equivalent to the case of using only (A) metal hydroxide can be obtained without using (A) metal hydroxide. And since (A) a metal hydroxide is not used, in the vinyl chloride resin composition, the fall of the various characteristics by (A) metal hydroxide can be prevented. Thereby, electrical characteristics, thermal stability, cold resistance, and moldability can be further improved while maintaining the flame retardancy of the vinyl chloride resin composition.

In the present embodiment, the content of (B) amorphous silica, (C1) hydrotalcite, and (C2) calcined clay may be in the following range with respect to 100 parts by mass of the vinyl chloride resin.
(B) Amorphous silica: 4 to 15 parts by mass, preferably 4 to 10 parts by mass (C1) Hydrotalcite: 5 to 30 parts by mass, preferably 5 to 25 parts by mass Parts / (C2) calcined clay: 4 to 15 parts by mass, preferably 5 to 10 parts by mass

  Next, examples of the present invention will be described.

(1) Material The materials used in Reference Examples, Examples and Comparative Examples are as follows.

  As a vinyl chloride resin, "TH-1700" (degree of polymerization 1700) manufactured by Taiyo PVC Co., Ltd. was used.

  As a plasticizer, trimellitic alkyl trimellitic acid (hereinafter abbreviated as n-TOTM) (“Trimex No8” manufactured by Kao Corporation) was used.

(A) The following four types were used as metal hydroxides.
(A1) Aluminum hydroxide: “Hijilite H-42M” (average particle size 1 μm) manufactured by Showa Denko KK
(A2) Aluminum hydroxide: “Hijilite H-43M” (average particle size: 0.75 μm) manufactured by Showa Denko KK
(A3) Aluminum hydroxide: “Hijilite H-32” (average particle size 8 μm) manufactured by Showa Denko KK
(A4) Aluminum hydroxide: “Hijilite H-42S” manufactured by Showa Denko KK (average particle size 1 μm, surface-treated)

  (B) “SIDISTAR 120U” manufactured by Elchem Co., Ltd. was used as amorphous silica.

  (C1) “HT-1” manufactured by Sakai Chemical Co., Ltd. was used as the hydrotalcite.

  (C2) “SP # 33” manufactured by BASF Corporation was used as the calcined clay.

Moreover, the following were used as other additives.
・ Lead-free stabilizer: “NL-HT7” manufactured by Mizusawa Chemical Co., Ltd.
・ Crosslinking aid: Trimethylolpropane triacrylate (Shin Nakamura Chemical Co., Ltd. “NK Ester H-200”)
Calcium carbonate: “SCP # 2010” manufactured by Sankyo Flour Milling Co., Ltd.
・ "NANO-200" manufactured by Zhengzhou, China

(2) Preparation of vinyl chloride resin composition In Reference Examples 1 to 5, a vinyl chloride resin composition was prepared using (B) amorphous silica, (C1) hydrotalcite, and (A) metal hydroxide. did.

  In Reference Example 1, 100 parts by mass of vinyl chloride resin, 44 parts by mass of n-TOTM as a plasticizer, 4 parts by mass of (B) amorphous silica, (C1) 7 parts by mass of hydrotalcite, (A) As a metal hydroxide, (a1) 5 parts by weight of aluminum hydroxide, and 4 parts by weight of a non-lead stabilizer and 4 parts by weight of a crosslinking aid were added and mixed as other additives. This mixture was kneaded with an open roll mixer heated to 140 ° C. Thereafter, the kneaded product was cooled and formed into pellets, whereby the vinyl chloride resin composition of Reference Example 1 was prepared. The preparation conditions are shown in Table 1 below.

  In Reference Examples 2 to 5, except that the amount of (A) metal hydroxide, (B) amorphous silica, and (C1) hydrotalcite was added, and the type and amount of other additives were changed, Similarly to Reference Example 1, vinyl chloride resin compositions of Reference Examples 2 to 5 were prepared.

  In Reference Examples 6 to 9, vinyl chloride resin compositions were prepared in the same manner as in Reference Example 1 except that (A) metal hydroxide, (B) amorphous silica, and (C2) calcined clay were used. The preparation conditions are shown in Table 2 below.

  In Examples 1 to 6, vinyl chloride resin compositions were prepared in the same manner as in Reference Example 1 except that (B) amorphous silica, (C1) hydrotalcite, and (C2) calcined clay were used. The preparation conditions are shown in Table 3 below.

  In Reference Examples 10 to 16, a vinyl chloride resin was used in the same manner as in Reference Example 1 except that (A) metal hydroxide, (B) amorphous silica, (C1) hydrotalcite, and (C2) calcined clay were used. A composition was prepared. The preparation conditions are shown in Table 4 below.

  In Comparative Examples 1 to 7, vinyl chloride resin compositions were prepared in the same manner as in Reference Example 1 except that antimony trioxide, (A) metal hydroxide, and (C2) calcined clay were used in appropriate combination. The preparation conditions are shown in Table 5 below.

(3) Production of insulated wire Next, insulated wires were produced using the vinyl chloride resin compositions of Examples 1 to 6, Reference Examples 1 to 16 and Comparative Examples 1 to 7 prepared above. Specifically, the prepared vinyl chloride resin composition is melt-extruded on the outer periphery of a twisted conductor (outer diameter 0.94 mm) obtained by twisting 26 tin-plated annealed copper wires having an outer diameter of 0.16 mm as a conductor. Extrusion coating was performed with a coating thickness of 0.5 mm to form an insulating coating with a thickness of 0.5 mm. Thereafter, the insulating coating was irradiated with an electron beam at a dose of 3.5 Mrad, and electron beam crosslinking was performed to produce an insulated wire.

(4) Evaluation method Next, about the insulation coating of the obtained insulated wire, a flame retardance, an electrical property, thermal stability, cold resistance, and moldability were evaluated. Hereinafter, the evaluation method will be described.

(Flame retardance)
As flame retardancy, a vertical flame retardant test was performed in accordance with the VW-1 test defined in UL1581. In this example, a test was performed on five insulated wires, and “◯” indicates a case where all five wires passed and “x” indicates a case where even one wire failed.

(Electrical characteristics)
As electrical characteristics, the following two tests were conducted based on UL758 for the insulated wire in the initial state and the insulated wire after standing for 168 hours in an environment of 136 ° C. “○”, and “x” otherwise.
(I) Each insulated wire after the initial state and after heat deterioration was wound around a mandrel having a diameter of 5 mm six times, a predetermined voltage was applied in water, and a breakdown voltage until dielectric breakdown was measured. Then, assuming that the breakdown voltage of the insulated wire in the initial state is A, the breakdown voltage of the insulated wire after thermal deterioration is B, and the case where A is 15 kV or more and B / A is 0.9 or more is determined to be acceptable.
(Ii) A metal foil was wound around each of the insulated wires after the initial state and after the heat deterioration, and electricity was applied at a rated condition of 105 ° C./2000 V for 1 minute. About the insulated wire after an initial state and heat deterioration, the case where neither short-circuited was set as the pass.

(Thermal stability)
As the thermal stability, the following two tests were conducted, and “◯” was given when both tests were passed, and “x” was given otherwise.
(I) The insulated wire is thermally deteriorated at 150 ° C., the time when the absolute value of the tensile elongation of the insulating coating after the heat deterioration becomes 50% is measured, and the case where the time is 500 hours or more is passed, less than 500 hours If it is
(Ii) The varnish specified in the CSA test was applied to an insulated wire, dried at 105 ° C. for 30 minutes, and then cured at 150 ° C. for 20 hours. This was wound six times around a mandrel having a diameter of 1 mm, and the case where no crack was generated in the insulating coating was regarded as acceptable.

(Cold resistance)
For cold resistance, leave the insulated wire in an environment of -35 ° C for 1 hour, wrap it around a mandrel with a diameter of 1 mm for 6 turns, and the insulation coating will not crack. It was set as “x”.

(Molding processability)
As the moldability, the following two tests were performed, and “◯” was given when both tests were passed, and “x” was given otherwise.
(I) Using a 40 mm extruder, the vinyl chloride resin composition is extrusion-coated at a linear speed of 400 m / min, and an outer diameter error occurs due to spark omission derived from the vinyl chloride resin composition or occurrence of bumps and die scum. The case where it did not pass was determined to be acceptable, and the case where it occurred was regarded as unacceptable.
(Ii) A sample at the initial stage of extrusion and a sample after the extrusion coating was performed for 1 hour were collected, and the appearance of the insulation coating was not confirmed to be rough, and the insulation coating was observed by observation with an optical microscope at a magnification of 100. The case where foaming was not confirmed was set as the pass.

(5) Evaluation results In Reference Examples 1 to 5, when (B) amorphous silica and (C1) hydrotalcite are used, the content of (A) metal hydroxide is reduced to 7 parts by mass or less. Even so, it was confirmed that the desired flame retardancy can be maintained. In addition, since the content of (A) the metal hydroxide is reduced to 7 parts by mass or less, it is possible to suppress deterioration of electrical characteristics, thermal stability, cold resistance and moldability, and to improve these characteristics. confirmed.

  In Reference Examples 6 to 9, by using (B) amorphous silica and (C2) calcined clay, as in Reference Examples 1 to 5, while maintaining flame retardancy, electrical characteristics, thermal stability, cold resistance It was confirmed that the processability and moldability could be improved.

  In Examples 1 to 6, by using (B) amorphous silica, (C1) hydrotalcite, and (C2) calcined clay, (A) desired flame retardancy can be achieved without using a metal hydroxide. It was confirmed that it was obtained. In Examples 1 to 6, it was confirmed that the electrical properties, thermal stability, cold resistance and molding processability of the insulating coating can be further improved as compared with Reference Examples 1 to 9 using (A) metal hydroxide. It was done.

  In Reference Examples 10 to 16, by using 7 parts by mass or less of (A) metal hydroxide together with (B) amorphous silica, (C1) hydrotalcite, and (C2) calcined clay, the flame retardancy and electrical characteristics are used. It was confirmed that the thermal stability, cold resistance and moldability were improved. In Reference Examples 10 to 16, since the content of the flame retardant component is increased by using (C1) hydrotalcite and (C2) calcined clay, the insulating coating is compared with Reference Examples 1 to 9. It was confirmed that the flame retardancy can be further improved.

  In Reference Example 4 and Reference Example 9 and the like, the cost can be reduced while maintaining various characteristics by using calcium carbonate.

  Comparative Example 1 is an example using antimony trioxide and (C2) calcined clay. In Comparative Example 1, it was confirmed that the flame resistance of the insulating coating was low because the content of antimony trioxide was small. Specifically, three of the five insulated wires burned in the VW-1 test. In Comparative Example 1, since antimony trioxide is contained, the cost is high and the environmental load is increased.

  Comparative Example 2 is an example using (a4) 15 parts by mass of aluminum hydroxide together with (C2) calcined clay. In Comparative Example 2, since the content of (A) the metal hydroxide is more than 7 parts by mass, the flame resistance of the insulating coating can be improved, but the thermal stability and the moldability are lowered. Specifically, since the thermal stability was lowered, when the insulating coating was thermally deteriorated at 150 ° C., the time for which the tensile elongation of the insulating coating was 50% was less than 350 hours, and a winding test was performed. Sometimes the insulation coating cracked. Further, since the moldability was lowered, a die scum was generated during the molding process, and an outer diameter error occurred in the insulating coating due to the adhesion of the die scum.

  In Comparative Example 3, the type of (A) metal hydroxide was changed from (a4) aluminum hydroxide (surface treated) used in Comparative Example 2 to (a1) aluminum hydroxide (no surface treatment). It is. In Comparative Example 3, as in Comparative Example 2, it was confirmed that the thermal stability and molding processability of the insulating coating were lowered. From this, it can be seen that (A) the metal hydroxide has no effect depending on the presence or absence of the surface treatment. In Comparative Example 3, it was confirmed that dice was generated and the thickness of the insulation coating varied.

  Comparative Example 4 is an example in which the content of (A) the metal hydroxide is set to 22 parts by mass more than Comparative Example 3. In Comparative Example 4, since the content of (A) metal hydroxide was further increased as compared with Comparative Example 3, in addition to thermal stability and molding processability, electrical characteristics and cold resistance were lowered. In Comparative Example 4, as in Comparative Example 3, it was confirmed that die scum was generated.

  Comparative Example 5 is an example in which the content of (A) the metal hydroxide is 8 parts by mass less than Comparative Example 3. In Comparative Example 5, since there were few flame retardant components, it was confirmed that the flame retardance that passes the VW-1 test cannot be obtained. Further, it was confirmed that the molding processability was poor because the content of the lead-free stabilizer was large and the external activity was greatly affected in the vinyl chloride resin composition.

  Comparative Example 6 is an example in which the type of (A) metal hydroxide was changed from (a1) aluminum hydroxide used in Comparative Example 5 to (a3) aluminum hydroxide having a large particle size. In Comparative Example 6, not only the flame retardancy was low as in Comparative Example 5, but also the cold resistance was further lowered because the particle size of aluminum hydroxide was increased.

  Comparative Example 7 is an example in which antimony trioxide is further added to Comparative Example 5. In Comparative Example 7, since the content of the flame retardant component was small, it was confirmed that the same result as in Comparative Example 5 was obtained.

1 Insulated wire 10 Conductor 11 Insulation coating

Claims (5)

  A vinyl chloride resin composition containing a vinyl chloride resin, a plasticizer, amorphous silica, hydrotalcite, and calcined clay, and containing no metal hydroxide.   An insulated wire comprising a conductor and an insulating coating formed from the vinyl chloride resin composition according to claim 1 on the outer periphery of the conductor.   The insulated wire according to claim 2, wherein the insulating coating is crosslinked.   The manufacturing method of an insulated wire which has the process of extrusion-coating the vinyl chloride resin composition of Claim 1 on the outer periphery of a conductor, and forming insulation coating.   The manufacturing method of the insulated wire of Claim 4 which further has the process of bridge | crosslinking the said insulation coating.

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