JP5716653B2 - Polyvinyl chloride resin composition, electric wire and cable using the same - Google Patents

Description

  The present invention relates to a polyvinyl chloride resin composition, an electric wire and a cable using the same.

  Since the polyvinyl chloride resin can widely contain various additives, a wide range of mechanical characteristics and other various characteristics can be realized.

  The polyvinyl chloride resin includes a hard polyvinyl chloride resin composition and a soft vinyl chloride resin composition. Rigid polyvinyl chloride resin compositions are used for molded articles such as exteriors of aircraft, vehicles and other transportation equipment, furniture, office goods, housing materials such as home appliances, and parts of semiconductor devices. The soft polyvinyl chloride resin composition contains a large amount of a plasticizer that imparts flexibility, and is used for insulating layers such as electric wires and cables that require flexibility.

  Among electric wires and cables, especially in the case of electric wires and cables used for internal wiring of electric and electronic devices, the insulating layer used requires high flame resistance (for example, pass the UL standard VW-1 test). It is done. For this reason, various flame retardants which impart flame retardancy are added to the polyvinyl chloride resin constituting the insulating layer.

  The applicant has already proposed a soft polyvinyl chloride resin composition to which a flame retardant is added (see, for example, Patent Document 1). According to Patent Document 1, as a flame retardant, zinc borate, metal hydroxide, and antimony trioxide are combined, and by adding a predetermined amount of flame retardant or plasticizer, flame retardancy, heat resistance, cold resistance, and It can be set as the polyvinyl chloride resin composition excellent in volume resistivity.

  However, antimony compounds used as flame retardants tend to be refrained from use in recent years due to concerns about adverse effects on the environment and the human body. For example, antimony trioxide has been designated as a deleterious substance because it is weakly irritating to the skin and mucous membranes. As its toxicity, the carcinogenicity of lung cancer has been pointed out by experiments administered to air for 55 weeks to rats. Due to this carcinogenicity, antimony compounds are classified into Group 2B (which may be carcinogenic to humans) by the International Cancer Research Organization (IARC) in terms of carcinogenicity for humans.

  In addition, antimony compounds as mineral resources are at risk of supply instability and price increase due to the uneven distribution of production areas and the tight supply and demand.

  Under these circumstances, a soft flame-retardant polyvinyl chloride resin composition that does not contain an antimony compound is required as a resin composition that constitutes an insulating layer of an electric wire / cable. For example, a resin composition using a combination of zinc stannate and zinc borate as an alternative to antimony trioxide has been proposed (see, for example, Patent Document 2). According to Patent Document 2, a soft flame-retardant polyvinyl chloride resin composition containing no antimony trioxide can be obtained by using zinc stannate and zinc borate together as a flame retardant.

  Zinc contained in zinc compounds such as zinc stannate and zinc borate acts as a catalyst for accelerating carbonization by eliminating hydrogen chloride in the polyvinyl chloride resin and contributing to the flame retardancy of the polyvinyl chloride resin. . The structure in which zinc contributes to the flame retardancy of the polyvinyl chloride resin will be described below.

Polyvinyl chloride resin is decomposed by heating and ignited and then burns, but desorbs hydrogen chloride (dehydrochlorination reaction) upon heating. Zinc promotes the dehydrochlorination reaction and further promotes the dehydrochlorination reaction by reacting with the desorbed hydrogen chloride to produce zinc chloride. Due to the elimination of hydrogen chloride, the polyvinyl chloride resin deteriorates and finally becomes a carbonized layer. The carbonized layer has a heat insulating effect and can suppress ignition and combustion of the polyvinyl chloride resin. Thus, according to the zinc compound as a flame retardant, the dehydrochlorination reaction of the polyvinyl chloride resin is promoted to deteriorate the resin prior to the combustion of the resin (to make a carbonized layer). Can contribute to flammability.

  When the insulating layer composed of the resin composition of Patent Document 2 is heated in a combustion temperature range (generally 300 ° C. or higher), the dehydrochlorination reaction is accelerated by zinc and carbonizes quickly. And the surface of an insulating layer is coat | covered with the carbonization layer, and combustion will be suppressed.

JP 2009-126963 A Japanese Patent Laid-Open No. 11-80474

  By the way, the polyvinyl chloride resin composition is heated at a predetermined temperature and molded into an insulating layer of an electric wire. The heating temperature (molding temperature range) during the molding process is 120 ° C to 150 ° C.

  In this respect, the vinyl chloride resin composition of Patent Document 2 has a problem in that it deteriorates due to heating during the molding process, and the properties of the molded insulating layer and the like deteriorate. The polyvinyl chloride resin causes a dehydrochlorination reaction even in the molding temperature range, although it is smaller than the combustion temperature range. For this reason, in Patent Document 2 containing a zinc compound, the dehydrochlorination reaction is promoted, and the deterioration of the resin proceeds.

  In other words, the zinc compound acts as a catalyst for promoting the dehydrochlorination reaction, but contributes to the flame retardancy of the polyvinyl chloride resin by the catalytic action in the combustion temperature range, but in the molding processing temperature range, the polychlorination is caused by the catalytic action. The deterioration of the vinyl resin is promoted to reduce the stability (heat resistance) of the resin against the heat load.

  Moreover, the above-mentioned Patent Document 2 uses zinc stannate and zinc borate in combination as a flame retardant, and since the zinc content in the resin composition increases as a result, the dehydrochlorination reaction is high, and the heat resistance of the resin Will be further reduced.

  Thus, although patent document 2 does not contain a harmful antimony compound, since zinc stannate and zinc borate, which are alternatives, are used in combination, it is difficult to achieve at least both flame retardancy and heat resistance.

  The present invention has been made in view of such problems, and its purpose is to contain a polyvinyl chloride resin composition that does not contain an antimony compound and has an excellent balance of flame retardancy, heat resistance, cold resistance, and electrical insulation. It is to provide an object, an electric wire and a cable using the object.

A first aspect of the present invention is a polyvinyl chloride resin composition containing a trimellitic acid ester as a plasticizer and a flame retardant, and 8 mass in terms of zinc content as the flame retardant. % Of fatty acid zinc containing zinc of 16% by mass or less, metal hydroxide, and calcined clay, and the content of the plasticizer is 100% by mass of the polyvinyl chloride resin composition. 20 mass% or more and 30 mass% or less, the content of the fatty acid zinc is 0.1 mass% or more and 0.6 mass% or less, the content of the metal hydroxide is 5 mass% or more and 15 mass% or less, the calcined clay Is a polyvinyl chloride resin composition containing 5 mass% or more and 15 mass% or less and containing no antimony trioxide .

  The 2nd aspect of this invention is an electric wire which has an insulating layer comprised from the polyvinyl chloride resin composition of a 1st aspect.

  A third aspect of the present invention is a cable that bundles a plurality of electric wires and has a sheath on the outer periphery thereof, and at least the sheath is a cable composed of the polyvinyl chloride resin composition according to the first aspect. .

  According to the present invention, it is possible to provide a polyvinyl chloride resin composition which does not contain antimony trioxide and has an excellent balance of flame retardancy, heat resistance, cold resistance and electrical insulation, and an electric wire and a cable using the same. it can.

It is a conceptual diagram which shows the correlation with the dehydrochlorination reaction of a zinc compound, and temperature. It is sectional drawing of the electric wire concerning one Embodiment of this invention. It is sectional drawing of the cable concerning one Embodiment of this invention.

  As described above, the resin composition used for the insulating layer of the electric wire is required to have predetermined flame retardancy and heat resistance. For example, in the case of a resin composition used for an insulating layer of a heat-resistant electric wire for equipment having a rated temperature of 105 ° C., it is required to pass a UL standard VW-1 test as flame retardancy. In addition, as heat resistance, heat resistance after 168 hours at 150 ° C. is required in consideration of heat load during molding.

  However, a polyvinyl chloride resin composition containing a zinc compound such as zinc stannate as an alternative to the antimony compound has made it difficult to achieve both flame retardancy and stability against heat load (heat resistance). This is because, as described above, the zinc compound promotes the dehydrochlorination reaction and contributes to the flame retardancy of the polyvinyl chloride resin, while reducing the heat resistance against heat load such as during molding. .

  Therefore, the present inventors considered that the correlation between the magnitude of the catalytic action of the zinc compound for the dehydrochlorination reaction and the heating temperature of the resin differs depending on the type of the zinc compound, and examined the selection of the zinc compound. Specifically, considering the molding processing temperature range (120 ° C. to 150 ° C.) and the combustion temperature range (300 ° C. to) as the heating temperature of the resin, the magnitude of the catalytic action of the zinc compound in each temperature range is examined. Went.

  As a result, the present inventors focused on fatty acid zinc with limited zinc content among zinc compounds. The fatty acid zinc with limited zinc content has been found to promote the dehydrochlorination reaction in the combustion temperature range, but this effect is smaller in the molding temperature range than in other zinc compounds. Hereinafter, this point will be described.

  As described above, in the polyvinyl chloride resin composition used for the insulating layer of the electric wire, the characteristic required in the combustion temperature range (300 ° C.-) is flame retardancy, and the molding temperature range (120 ° C.-150 ° C.). ) Is required for heat resistance.

  In order to realize flame retardancy, it is necessary to promote the formation of a carbonized layer (deterioration of the resin) during combustion by actively acting zinc as a catalyst for dehydrochlorination reaction at a heating temperature of 300 ° C. or higher. There is.

  In order to achieve heat resistance, it is necessary to reduce the action of zinc as a catalyst for the dehydrochlorination reaction as much as possible at a heating temperature of 120 ° C. to 150 ° C. to suppress deterioration of the resin during molding processing. .

  In other words, the polyvinyl chloride resin composition containing a zinc compound has a large dehydrochlorination reaction and is likely to deteriorate in a relatively high temperature environment where the resin burns, while in a relatively low temperature environment where the resin is molded. Is required to have a small dehydrochlorination reaction and hardly deteriorate.

  In this respect, the conventional polyvinyl chloride resin composition containing zinc stannate and zinc borate has a large dehydrochlorination reaction in the combustion temperature range and exhibits high flame retardancy, and rapidly deteriorates due to heating of the resin. However, since the dehydrochlorination reaction is large even in the molding temperature range, the resin composition is significantly deteriorated and the heat resistance becomes insufficient. The correlation between the magnitude of the catalytic action of the zinc compound for the dehydrochlorination reaction and the heating temperature of the resin is shown in a straight line (1) in FIG. In FIG. 1, the horizontal axis represents the heating temperature of the resin, and the vertical axis represents the magnitude of the catalytic action of the zinc compound for the dehydrochlorination reaction. Further, each of the straight lines (1) to (3) is a relative expression by comparing the magnitude of the catalytic action.

  On the other hand, when the content of the flame retardant is reduced in order to suppress a decrease in the heat resistance of the resin, the correlation of the straight line (2) in FIG. 1 is shown. That is, as shown by the straight line (2) in FIG. 1, when the content of the flame retardant is small, the dehydrochlorination reaction in the molding temperature range is relatively small, and the reduction in heat resistance can be suppressed. However, since the content of the flame retardant is small, the dehydrochlorination reaction in the combustion temperature range is small, the formation of the carbonized layer is insufficient, and the flame retardancy is insufficient.

  According to the straight line (1) and straight line (2) in FIG. 1, the heat resistance in the molding temperature range and the flame retardance in the combustion temperature range can be obtained only by adjusting the content of zinc stannate and zinc borate. It is difficult to balance the sex.

  On the other hand, the correlation when fatty acid zinc is used is different from the case where the zinc stannate and zinc borate are used, and is shown by the straight line (3) in FIG. According to the fatty acid zinc, there is a large inclination indicating the variation in the catalytic action in the dehydrochlorination reaction with respect to the change in temperature. For this reason, the dehydrochlorination reaction is small in the molding temperature range where the temperature is relatively low, and sufficient heat resistance can be obtained by suppressing the deterioration of the resin. Furthermore, the dehydrochlorination reaction is large in the relatively high combustion temperature range, and the carbonized layer can be efficiently formed by deteriorating the resin.

  In addition, the present inventors differed in the variation of the catalytic action of fatty acid zinc with respect to temperature change due to the difference in zinc content of fatty acid zinc, and the zinc content should be in the range of 8 to 16% by mass. It has been found that sufficient flame retardancy in the combustion temperature range can be obtained, and sufficient heat resistance in the molding temperature range can be obtained.

  In addition, by combining a metal hydroxide and calcined clay with the fatty acid zinc, a polyvinyl chloride resin composition having both flame resistance and heat resistance and excellent balance of properties such as cold resistance and electrical insulation is provided. We found out what we can do and came to create the present invention.

  Below, the polyvinyl chloride resin composition which concerns on one Embodiment of this invention is demonstrated.

(Polyvinyl chloride resin composition)
The polyvinyl chloride resin composition of this embodiment includes trimellitic acid ester as a plasticizer, fatty acid zinc having a zinc content of 8% by mass to 16% by mass, a metal hydroxide, and a fire retardant as a flame retardant. Clay. And with respect to 100 mass% of polyvinyl chloride resin compositions, content of a plasticizer is 20 mass% or more and 30 mass% or less, content of fatty acid zinc is 0.1 mass% or more and 0.6 mass% or less, metal The hydroxide content is 5% by mass to 15% by mass and the calcined clay content is 5% by mass to 15% by mass.

  Examples of the polyvinyl chloride resin include homopolymers of vinyl chloride, that is, polyvinyl chloride, copolymers of vinyl chloride and other copolymerizable monomers, and mixtures thereof. A polyvinyl chloride resin having an average polymerization degree of 1000 to 2500 can be used.

The plasticizer is an additive for imparting flexibility to the polyvinyl chloride resin and facilitating processing. In this embodiment, trimellitic acid ester is used as a plasticizer. The trimellitic acid ester is preferably an ester of trimellitic acid and an alcohol having 8 carbon atoms. According to this configuration, the heat resistance of the polyvinyl chloride resin composition can be improved. Further, an ester of trimellitic acid and a branched alcohol having 8 carbon atoms is more preferable. According to this configuration, it is possible to improve heat resistance and stabilize electrical insulation.
The trimellitic acid ester may be appropriately blended with a pyromellitic acid ester plasticizer, a polyester plasticizer, a phthalic acid ester plasticizer, an epoxy plasticizer, or a dicarboxylic acid ester plasticizer.

  The content of the plasticizer is 20% by mass to 30% by mass with respect to 100% by mass of the polyvinyl chloride resin composition. When the content is less than 20% by mass, the cold resistance of the resin composition is inferior. On the other hand, when it exceeds 30% by mass, combustible components in the resin composition increase and it becomes difficult to obtain a flame-retardant effect.

  As the flame retardant, fatty acid zinc, metal hydroxide, and calcined clay are used in combination.

  Fatty acid zinc is a compound comprising an aliphatic carboxylic acid (fatty acid) and a metal salt of zinc. In this embodiment, fatty acid zinc having a zinc content of 8% by mass to 16% by mass is used as the fatty acid zinc. Fatty acid zinc can achieve both the flame retardancy and heat resistance of the polyvinyl chloride resin composition when the zinc content is 8 mass% or more and 16 mass% or less. According to the fatty acid zinc having a predetermined zinc content, as shown by the straight line (3) in FIG. 1, the dehydrochlorination reaction is high in the combustion temperature range and the resin is rapidly deteriorated to show flame retardancy. In the molding temperature range, the dehydrochlorination reaction is relatively small and the deterioration of the resin can be suppressed. In addition, the fatty acid zinc imparts flexibility to the polyvinyl chloride resin to improve the extrusion moldability, and can improve the dispersibility of other flame retardants and further improve the flame retardancy. When the zinc content in the fatty acid zinc is less than 8% by mass, it is difficult to obtain sufficient flame retardancy and heat resistance, and when it exceeds 16% by mass, the heat resistance of the resin deteriorates.

  The fatty acid constituting the fatty acid zinc is not limited as long as the zinc content of the fatty acid zinc can be adjusted to the above numerical range. Examples of fatty acids include saturated fatty acids such as capric acid, lauric acid, myristic acid, pentadecylic acid, palmitic acid, margaric acid, stearic acid, tuberculostearic acid, arachidic acid, behenic acid, lignoceric acid, and unsaturated acids such as oleic acid Examples include fatty acid derivatives such as fatty acids and hydroxystearic acid, which can be used alone or in combination.

Examples of the fatty acid zinc include zinc laurate (zinc content: about 14% by mass) and zinc stearate (zinc content: about 10.7% by mass). Moreover, fatty acid zinc can also be used individually by 1 type or in combination of 2 or more types.

The content of fatty acid zinc is 0.1% by mass to 0.6% by mass with respect to 100% by mass of the polyvinyl chloride resin composition. More preferably, the content is 0.2% by mass or more and 0.5% by mass or less.
If the content of the fatty acid zinc is within the above numerical range, the fatty acid zinc captures hydrogen chloride from the polyvinyl chloride resin, contributes to the stability against the heat load, and improves the heat resistance of the resin. When the content is less than 0.1% by mass, since the zinc content in the resin composition is reduced, the formation of a carbonized layer at the time of combustion of the resin becomes insufficient, and a sufficient flame retardant effect cannot be obtained. When it exceeds 0.6 mass%, since the zinc content in the resin composition increases, heat resistance at a heating temperature of 150 ° C. cannot be obtained. Furthermore, the zinc chloride produced by the reaction with the desorbed hydrogen chloride accelerates the decomposition of the plasticizer and lowers the molecular weight of the resin composition. Also, the formation of a carbonized layer progresses in the initial stage of combustion, and a strong carbonized layer is formed. Since it is not formed, a sufficient flame retardant effect cannot be obtained.

  The metal hydroxide captures hydrogen chloride desorbed from the polyvinyl chloride resin during heating such as molding and improves the thermal stability (heat resistance) of the polyvinyl chloride resin. Further, the metal hydroxide is thermally decomposed at 200 ° C. or higher to release moisture, thereby reducing the temperature of the polyvinyl chloride resin (by endothermic reaction) and imparting flame retardancy. As the metal hydroxide, for example, aluminum hydroxide can be used.

  The content of the metal hydroxide is 5% by mass to 15% by mass with respect to 100% by mass of the polyvinyl chloride resin composition. Preferably they are 5 mass% or more and 10 mass% or less. If it is less than 5% by mass, the endothermic reaction during combustion is insufficient and it becomes difficult to obtain flame retardancy. On the other hand, when it exceeds 15 mass%, the formation ability of the carbonized layer by a flame retardant falls and it becomes difficult to obtain a flame retardant effect.

  The calcined clay is obtained by calcining wet kaolin, releasing crystal water and destroying the original crystal structure. Due to this structure, the calcined clay has high activity, and adsorbs and immobilizes free ions to improve the electrical insulation of the resin composition. Moreover, since it has a porous structure, it has a property of taking in organic low-molecular components and contributes to flame retardancy.

  The content of the baked clay is 5% by mass to 15% by mass with respect to 100% by mass of the polyvinyl chloride resin composition. Preferably they are 5 mass% or more and 10 mass% or less. When it is less than 5% by mass, it becomes difficult to obtain the flame retardancy and electrical insulation of the resin composition. On the other hand, if it exceeds 15% by mass, the flame resistance and the heat resistance are not affected, but the cold resistance is deteriorated and the balance of properties is deteriorated.

  In addition to the plasticizer and flame retardant described above, stabilizers, fillers, pigments, other additives, and the like may be appropriately added to the polyvinyl chloride resin composition. A stabilizer, a filler, etc. are not specifically limited, A well-known thing can be used. Each content is preferably 2 parts by weight or more and 10 parts by weight or less for the stabilizer and 5 parts by weight or more and 40 parts by weight or less for the filler with respect to 100 parts by weight of the vinyl chloride resin.

As the stabilizer, known composite stabilizers such as calcium-zinc and barium-zinc can be used. As the composite stabilizer, those other than those containing lead, which have a negative effect on the environment and the human body, are preferred, and examples thereof include those containing hydrotalcite as a main component. Hydrotalcite can supplement hydrogen chloride generated during heat load such as during molding of the resin composition by ion exchange. In addition, when fatty acid zinc etc. are contained in a composite stabilizer, the weight fraction is added and the weight fraction of fatty acid zinc etc. in a resin composition is computed.

  Other additives include β-diketones that have the effect of substituting unstable chlorine and capturing metal chlorides, polyhydric alcohols that mainly capture metal chlorides (such as zinc chloride), and elimination of double bonds. Perchlorates that act, zeolites and fatty acid metal salts that act to trap hydrogen chloride, phenolic antioxidants that deactivate radicals, amine and thioether antioxidants that act to decompose peroxides and capture radicals An appropriate amount of an agent and an ultraviolet absorber can be added.

(Electric wires and cables)
Next, the electric wire concerning one Embodiment of this invention is demonstrated. The electric wire of this embodiment has an insulating layer comprised from the said polyvinyl chloride resin composition. Specifically, as shown in FIG. 2, in the electric wire 10, the outer periphery of the conductor 1 is covered with an insulating layer 2 composed of the polyvinyl chloride resin composition.

  Further, a plurality of electric wires 10 shown in FIG. 2 can be bundled to form a cable. Specifically, as shown in FIG. 3, the cable 20 is formed by bundling an electric wire 10 (wire core) covering a conductor 1 with an insulating layer 2 together with an intervening 4, and applying a press-wound tape 5 on its outer periphery. A sheath 3 is formed. For the insulating layer 2 and the sheath 3, the polyvinyl chloride resin composition is used.

  The conductor 1 is not particularly limited with respect to the conductor diameter and material, and an optimal conductor can be appropriately selected according to the application. For example, the conductor 1 is formed of a metal material such as copper or a copper alloy. Further, the thicknesses of the insulating layer 2 and the sheath 3 are not particularly limited, and optimum thicknesses are selected according to applications.

  Next, the manufacturing method of the electric wire 10 and the cable 20 is demonstrated.

  First, a predetermined amount of a plasticizer and a flame retardant are added to a polyvinyl chloride resin and uniformly kneaded to form a polyvinyl chloride resin composition. The kneading method may be any method in which each component of the resin composition is substantially uniformly dispersed, mixed, and kneaded. For example, a Banbury mixer, a kneader, a co-directional twin-screw extruder, a bi-directional twin screw It can be kneaded with an extruder, a roll kneader, a batch kneader or the like. Subsequently, the polyvinyl chloride resin composition is extrusion coated on the outer periphery of the conductor 1 using a known wire coating extruder to produce the electric wire 10.

  The cable 20 is manufactured using the obtained electric wire 10. Specifically, a plurality of the obtained electric wires 10 are prepared, and these and the interposition 4 are twisted together by a known twisting machine, and then a presser winding tape is wound around the outside, and then a known wire coating extruder is used. The cable 3 is manufactured by extrusion-coating the sheath 3 using

(Effect of this embodiment)
According to the present embodiment, one or more effects shown below are produced.

According to this embodiment, the polyvinyl chloride resin composition includes trimellitic acid ester as a plasticizer, fatty acid zinc having a zinc content of 8% by mass to 16% by mass as a flame retardant, a metal hydroxide, and firing. Contains clay, each containing a predetermined amount.
By using fatty acid zinc having a predetermined zinc content, flame retardancy can be imparted when the resin is burned, and predetermined heat resistance can be imparted when the resin is molded. Moreover, flame retardance can be further improved by using a metal hydroxide and calcined clay as a flame retardant. Moreover, according to the metal hydroxide, predetermined heat resistance can be imparted by capturing hydrogen chloride desorbed from the vinyl chloride resin and suppressing the dehydrochlorination reaction. Moreover, according to the calcined clay, electrical insulation can be improved by adsorbing and fixing free ions. Furthermore, the cold resistance of a polyvinyl chloride resin composition can be improved by adjusting content of a flame retardant and a plasticizer.
Therefore, according to the configuration of the present embodiment, it is possible to provide a vinyl chloride resin composition that does not contain an antimony compound and has an excellent balance of flame retardancy, heat resistance, cold resistance, and electrical insulation.

  Moreover, according to this embodiment, an electric wire has the insulating layer comprised from the said polyvinyl chloride resin composition. In addition, the cable bundles a plurality of the electric wires and has a sheath formed of the polyvinyl chloride resin composition on the outer periphery thereof. According to this structure, it can be set as the electric wire or cable which does not contain a harmful | toxic antimony compound and is excellent in balance of characteristics, such as a flame retardance, heat resistance, cold resistance, and an electrical insulation.

  The flame retardant vinyl chloride resin compositions of the examples according to the present invention were prepared by the following methods and conditions. These examples are examples of the flame-retardant vinyl chloride resin composition according to the present invention, and the present invention is not limited to these examples.

  For polyvinyl chloride resin (degree of polymerization: 1300, TK1300, manufactured by Shin-Etsu Chemical), zinc laurate as a flame retardant (zinc content: about 14% by mass, ZS-3, manufactured by Nitto Kasei), as a flame retardant Add aluminum hydroxide (Hijilite H42M, Showa Denko), calcined clay as a flame retardant (SP # 33, manufactured by BASF), composite stabilizer described later, 10 seconds at low speed with a high-speed stirring mixer (Henschel mixer) Mixed. Thereafter, trimellitic acid ester (TOTM, manufactured by Kao) as a plasticizer was continuously added to the resin composition little by little and mixed at a high speed, and the resin temperature was raised to 110 ° C. to dry up. This was kneaded with a mixing roll set at 160 ° C. for 5 minutes to form a sheet of the polyvinyl chloride resin composition of Example 1. Note that TOTM as a plasticizer is an ester of trimellitic acid and an alcohol having 8 carbon atoms. The composite stabilizer is hydrotalcite 70% by mass, calcium stearate 7% by mass, dibenzoylmethane 6% by mass, phenolic antioxidant 6% by mass, thioether antioxidant 3% by mass, stearic acid 1% by mass, silica. A compounding agent containing 4% by mass and 3% by mass of calcium hydroxide was dispersed with a high-speed mixer.

  As shown in Table 1, the amount of each added is 58.0% by mass of vinyl chloride resin, 25.9% by mass of trimellitic acid ester, 100% by mass of the adjusted polyvinyl chloride resin composition, composite stability 2.15% by mass of agent, 0.45% by mass of zinc laurate (0.063% by mass in terms of zinc content), 5.00% by mass of aluminum hydroxide, and 8.50% by mass of calcined clay.

The sheeted resin composition of Example 1 was preheated at 170 ° C. for 3 minutes with a hot press machine, held at a pressure of 100 kgf / cm ² for 2 minutes, and cooled to room temperature in 5 minutes. Evaluation sheets (1 mm thickness, 2 mm thickness) were manufactured.

  The sheet-formed resin composition of Example 1 was cut into 2 mm square pellets and extrusion coated onto a conductor with a 40 mm extruder set at a cylinder temperature of 180 ° C and a head temperature of 185 ° C. Manufactured. The conductor used was a tin-plated copper wire with an outer diameter of 0.94 mm (26 strands of strands with an outer diameter of 0.16 mm), the coating thickness was 0.81 mm, and the outer diameter after coating was 2.56 mm.

  About the obtained electric wire of Example 1, heat resistance, cold resistance, electrical insulation, extrusion moldability, and a flame retardance were evaluated. Each evaluation method will be described below.

(Heat-resistant)
Regarding the heat resistance of the electric wire, a tensile test before and after heating was performed on the manufactured electric wire according to JIS K 6723. The heating temperature was set to 136 ° C. in consideration of the requirement for a 105 ° C. rated wire according to UL standards, and 150 ° C. in consideration of the heat load during the forming process. In heat resistance at 136 ° C., the tensile strength residual ratio after heating for 168 hours was 70% or more and the elongation residual ratio was 65% or more in accordance with UL standards. In heat resistance at 150 ° C., an elongation residual ratio of 50% or more after heating for 200 hours was regarded as acceptable.

(Cold resistance)
For the cold resistance of the electric wire, the embrittlement temperature was measured according to JIS K 6723 (6.6.1 equipment in the cold resistance test of Section 6.6, 6.6.2 operation) for the manufactured electric wire. -10 degrees C or less was set as the pass.

(Electrical insulation)
Volume resistivity at 30 ° C. according to JIS K 6723 (Measurement of thickness of 6.8.1 measuring device and electrode, 6.8.2 test piece and test piece in 6.8 volume resistivity test) And 1 × 10 ¹⁴ Ω · cm or more was regarded as acceptable.

(Extrudability)
Extruding the above-mentioned wire coating extrusion for 12 hours at a cylinder temperature of 180 ° C., a head temperature of 185 ° C., and a wire speed of 400 m / min. .

(Flame retardance)
About the manufactured electric wire, the VW-1 test of UL specification was implemented and it was set as the pass when 10 of 10 satisfied the standard.

(Examples 2 to 7)
In Examples 2-7, as shown in Table 1, the content of the plasticizer and flame retardant in Example 1 and the type of plasticizer and fatty acid zinc were changed, and the polyvinyl chloride resin composition was the same as in Example 1. Things were adjusted and electric wires were manufactured. In addition, zinc stearate (zinc content: about 10.7% by mass, Zn-St, manufactured by Nitto Kasei) was used as a different type of fatty acid zinc. In addition, tri-n-octyl trimellitate (n-TOTM, manufactured by Kao) was used as a different type of plasticizer.

  When the characteristics of the electric wires of Examples 2 to 7 were measured in the same manner as in Example 1, as shown in Table 1, in any evaluation items of heat resistance, cold resistance, electrical insulation, extrusion moldability, and flame retardancy It was a pass.

(Comparative Examples 1 and 2)
In Comparative Examples 1 and 2, as shown in Table 2, as fatty acid zinc, zinc montanate (zinc content: about 7% by mass, Zs-8, manufactured by Nitto Kasei), zinc caprylate (zinc content: about 22) The point which used the mass% and Wako Purechemical) was mainly different from Example 7. FIG. About a point other than that, the vinyl chloride resin composition was adjusted similarly to Example 7, and the electric wire was manufactured. In addition, the characteristics of the electric wires were evaluated in the same manner as in Example 7.

  In Comparative Example 1, zinc montanate (zinc content: about 7% by mass) was used, and the content was 0 so as to be the same as the zinc content (0.063% by mass) of the resin composition of Example 7. .88% by mass. When the characteristics of the manufactured electric wire were measured, the heat resistance and flame retardancy were insufficient.

  In Comparative Example 2, the content was 0 using zinc caprylate (zinc content: about 22% by mass) so as to be the same as the zinc content (0.063% by mass) of the resin composition of Example 7. .34% by mass. When the characteristic of the manufactured electric wire was measured, the flame retardance was insufficient. The reason for this is considered to be that the carbonized layer is formed in a low temperature region and the carbonized layer becomes brittle in the combustion region.

(Comparative Examples 3 and 4)
In Comparative Examples 3 and 4, as shown in Table 3, zinc stannate (zinc content: about 23% by mass, manufactured by Mizusawa Chemical) or zinc borate (zinc content: about The main difference is that 30% by mass (made by Mizusawa Chemical) is used. Otherwise, the vinyl chloride resin composition was prepared in the same manner as in Example 2 or 4 to produce an electric wire. Further, the characteristics of the electric wires were evaluated in the same manner as in Example 1.

In Comparative Example 3, zinc borate was used, and the content was set to 0.05% by mass (zinc content 0) so as to be equivalent to the zinc content (0.014% by mass) of the resin composition of Example 4. .015 mass%).
When the characteristics of the manufactured electric wire were measured, the flame retardancy was insufficient. In Comparative Example 3, zinc borate is used as a flame retardant, but since the content thereof is reduced, a predetermined heat resistance is obtained, but the carbonized layer by the dehydrochlorination reaction is efficiently produced in the combustion temperature range. Since it was not formed, sufficient flame retardancy was not obtained.

In Comparative Example 4, zinc stannate and zinc borate were used in combination, and the zinc stannate content was adjusted to be equal to the zinc content (0.041% by mass) of the resin composition of Example 2. The content of 03% by mass and zinc borate was 0.12% by mass (zinc content 0.045% by mass).
When the characteristics of the manufactured electric wire were measured, the heat resistance at 150 ° C. was insufficient. In Comparative Example 4, zinc stannate and zinc borate were used as flame retardants, and because the content was large, predetermined flame retardancy was obtained, but dehydrochlorination reaction occurred even in the molding processing temperature range. As a result, heat resistance deteriorated.

(Comparative Examples 5 and 6)
In Comparative Examples 5 and 6, as shown in Table 4, the main difference is that the content of fatty acid zinc is outside the scope of the present invention. Otherwise, the vinyl chloride resin composition was prepared in the same manner as in Example 2 or Example 3 to produce an electric wire. Further, the characteristics of the electric wires were evaluated in the same manner as in Example 1.

In Comparative Example 5, the zinc laurate content was 1.0% by mass, and the zinc content in the resin composition was 0.141% by mass. When the characteristics of the manufactured electric wire were measured, the heat resistance at 150 ° C. was insufficient.
In Comparative Example 6, the content of zinc stearate was 0.05% by mass, and the zinc content in the resin composition was 0.005% by mass. When the characteristics of the manufactured electric wire were measured, the extrusion moldability and flame retardancy were insufficient.

(Comparative Examples 7-12)
In Comparative Examples 7-12, as shown in Table 5, the vinyl chloride resin composition was the same as in Example 1 except that the content of the plasticizer, metal hydroxide, or calcined clay was outside the scope of the present invention. The electric wire was manufactured. Further, the characteristics of the electric wires were evaluated in the same manner as in Example 1.

In Comparative Example 7, the plasticizer content was increased from 30% by mass to 31.4% by mass. In Comparative Example 7, the flame retardancy was insufficient due to the large amount of combustible components in the composition.
On the other hand, in Comparative Example 8, the plasticizer content was less than 20% by mass and 19.8% by mass. In Comparative Example 8, the cold resistance and extrusion moldability were insufficient.

In Comparative Example 9, the content of the metal hydroxide was less than 5% by mass and was 4.2% by mass. In Comparative Example 9, since the endothermic effect during combustion was insufficient, the flame retardancy was insufficient.
On the other hand, in Comparative Example 10, the content of the metal hydroxide was increased from 15% by mass to 15.6% by mass. In Comparative Example 10, since the formed carbonized layer was fragile, the flame retardancy was insufficient.

In Comparative Example 11, the content of the calcined clay was less than 5% by mass and 4.2% by mass. In Comparative Example 11, electrical insulation and flame retardancy were insufficient.
On the other hand, in Comparative Example 12, the content of the metal hydroxide was increased from 15% by mass to 15.6% by mass. In Comparative Example 12, the cold resistance was insufficient.

DESCRIPTION OF SYMBOLS 1 Conductor 2 Insulating layer 3 Sheath 4 Interposition 5 Presser winding tape 10 Electric wire 20 Cable

Claims (3)

A polyvinyl chloride resin composition containing trimellitic acid ester as a plasticizer and a flame retardant,
As the flame retardant, zinc content is 8 wt% or more and 16 wt% or less fatty acid zinc, metal hydroxide, and calcined clay,
For 100% by mass of the polyvinyl chloride resin composition,
The plasticizer content is 20% by mass to 30% by mass, the fatty acid zinc content is 0.1% by mass to 0.6% by mass, and the metal hydroxide content is 5% by mass to 15%. mass% or less, the der content of 5 mass% to 15 mass% of calcined clay is, polyvinyl chloride resin composition, characterized by containing no antimony trioxide.   An electric wire comprising an insulating layer composed of the polyvinyl chloride resin composition according to claim 1.   A cable having a plurality of electric wires bundled and having a sheath on the outer periphery thereof, wherein at least the sheath is made of the polyvinyl chloride resin composition according to claim 1.

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