JP2001220481A - Polyvinyl chloride resin composition and insulated wire - Google Patents

Abstract

(57) [Problem] To provide a polyvinyl chloride resin composition which is free from environmental pollution and does not inhibit curing of an unsaturated polyester impregnated varnish, and an insulated wire using the same. The phenolic antioxidant content is 0.1%.
% By weight or less, stabilized with a non-lead-based stabilizer, and not containing lead, a polyvinyl chloride resin composition,
And an insulated wire using the polyvinyl chloride resin composition as an insulator.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an environmentally friendly polyvinyl chloride resin composition containing no lead and an insulated wire using the resin composition.

[0002]

2. Description of the Related Art Polyvinyl chloride resin is widely used as an insulator for electric wires because of its excellent flame retardancy in addition to electric and mechanical properties. Lead-based stabilizers such as tribasic lead sulfate and lead phthalate are frequently used in this polyvinyl chloride resin to increase heat resistance. However, in recent years, harmful lead has diffused into the atmosphere as fly ash during incineration of electric wires. There is a concern about environmental pollution such as wastewater and elution into groundwater during landfill.

[0003] For this reason, instead of lead-based stabilizers, calcium stearate, zinc stearate, calcium salts such as barium stearate, fatty acid metal salts having barium as a metal component, hydrotalcites, polyols, There has been proposed a composition in which heat resistance is enhanced by a lead-free compound such as a β-diketone compound and a metal salt thereof, which is a lead-free compound.

[0004]

However, when an electric wire having a polyvinyl chloride resin composition stabilized with a lead-free stabilizer as an insulator is used as a lead wire of a power transformer or the like, an unsaturated impregnating agent is used. It has been found that there is a disadvantage that the curing of the polyester varnish is significantly inhibited. Such a phenomenon is a phenomenon that cannot be seen in a conventional electric wire using a polyvinyl chloride resin composition containing a lead-based stabilizer as an insulator.

An object of the present invention is to provide a polyvinyl chloride resin composition and an insulated wire which do not hinder the curing of an unsaturated polyester varnish.

[0006]

In order to solve the above problems, the present invention provides a phenolic antioxidant having a content of 0.1%.
Provided is a polyvinyl chloride resin composition containing 1% by weight or less and stabilized by a non-lead-based stabilizer and containing no lead, and an insulated wire using the polyvinyl chloride resin composition as an insulator around a conductor.

The present inventors have conducted intensive studies on factors that have an adverse effect on the curability of an unsaturated polyester varnish.
It has been found that a lead-based stabilizer such as tribasic lead sulfate, which has been conventionally used to increase the heat resistance of a polyvinyl chloride resin, has significantly increased the curing of the varnish. As a result of extensively examining a method that does not cause varnish curing inhibition even in a lead-free stabilizer system having no such catalytic effect of curing acceleration, conventionally, conventionally, it was usually added mainly for the purpose of preventing the oxidation of the plasticizer, A phenolic antioxidant represented by 2,2-bis (4-hydroxyphenyl) -propane or pentaerythrityl-tetrakis [3- (3,5-di-t-hydroxyphenyl) propionate] is 0.1% It has been found that the varnish hardening inhibition can be prevented by controlling the content to not more than the weight%. When the addition amount of the phenolic antioxidant in the resin composition is as small as 0.1% by weight or less, the amount of the phenolic antioxidant transferred to the varnish is small, and as a result, the hardening of the varnish is not inhibited. If it exceeds 0.1% by weight, the amount transferred to the varnish increases, and curing is inhibited. Although the lower limit is not particularly defined, it is preferably 0.01% by weight or more for imparting heat resistance. It is not necessary to add a phenolic antioxidant.

The reason why the content can be improved by reducing the content of the phenolic antioxidant can be explained as follows. That is, in the lead-free stabilizer system, varnish curing inhibition occurs because the phenolic antioxidant in the polyvinyl chloride resin composition migrates to the varnish side when in contact with the varnish, and captures radicals generated during varnish curing. it is conceivable that. Therefore, it is improved by reducing the amount of the phenolic antioxidant, which has a strong adverse effect. The conventional phenol-based antioxidant seems to have some adverse effects even in the conventional lead-based stabilizer, but is considered to be covered by the strong hardening acceleration effect of the lead-based stabilizer.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As phenolic antioxidants, 2,6-di-t-butyl-4-methylphenol, n
-Octadecyl-3- (3 ', 5'-di-t-butyl-
4'-hydroxyphenyl) -propionate, 2,
2'-methylene-bis- (4-methyl-6-t-butylphenol), 2-t-butyl-6- (3'-t-butyl-5'-methyl-2'-hydroxybenzyl) -4-
Methylphenyl acrylate, 4,4'-butylidene-
Bis- (3-methyl-6-t-butylphenol),
4,4'-thio-bis- (3-methyl 6-t-butylphenol), bisphenol A, pentaerythrityl-
Tetrakis [3- (3,5-di-t-hydroxyphenyl) propionate], 1,3,5-tris (4-t-
Butyl-3-hydroxy-2,6-dimethylbenzyl)
Isocyanurate, 2,2-thio-diethylene-bis-
[3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], octadecyl-3- (3,5
-Di-t-butyl-4-hydroxyphenyl) propionate; Other 5- (3,5-di-t-
Butyl-4-hydroxybenzyl) -2-ethyl-n-
A type containing sulfur such as thioglycolate may be used. These may be used alone or in combination of two or more.

[0010] As a stabilizer used to increase the heat resistance of the polyvinyl chloride resin, calcium stearate,
Zinc stearate, calcium represented by barium stearate, zinc, fatty acid metal salts having barium as a metal component, hydrotalcites, polyols, β-diketone compounds and metal salts thereof, etc. Can also be used. The content of the fatty acid metal salt in the resin composition is preferably used in the range of 0.2 to 1% by weight. When the content is less than the lower limit, the HCl trapping effect becomes insufficient, and when the content exceeds the upper limit, the lubricity increases. Workability is reduced. Hydrotalcites are preferably used in a content of 1 to 3% by weight in the resin composition. If the content is less than the lower limit, the effect of capturing HCl is insufficient, and if it exceeds the upper limit, the cost increases.

In general, polyvinyl chloride resins include di- (2-ethylhexyl) phthalate and di-
phthalic acid esters such as n-octyl phthalate, diisononyl phthalate and diisodecyl phthalate;
Trimellitic acid esters such as (2-ethylhexyl) trimellitate, tri-n-octyl trimellitate, triisononyl trimellitate, and triisodecyl trimellitate; tetra- (2-ethylhexyl) pyromellitate; In addition to pyromellitic esters such as tetra-n-octyl pyromellitate and tetraisononyl pyromellitate, adipic esters, sebacic esters, azelaic esters, and paraffin chlorides may be used in accordance with a conventional method. Two or more can be used in combination. The compounding amount of these plasticizers is 100 polyvinyl chloride resin.
Although it is about 40 to 80 parts by weight per part by weight, it is not particularly specified because it is increased or decreased depending on the requirements of hardness and heat resistance.

In addition, a lubricant, a filler, a flame retardant auxiliary, a coloring agent, a termiticide,
Rat proofing agents can be added. When electron beam irradiation is performed, a crosslinking assistant such as triallyl isocyanurate, triallyl cyanurate, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, and pentaerythritol triacrylate is added.

[0013]

Next, examples of the present invention will be described together with comparative examples. A predetermined amount of the components shown in Table 1 was weighed and kneaded with a Banbury mixer to prepare a compound for extrusion. The compound was introduced into a 65 mm extruder set at 170 ° C., and extruded onto a tin-plated copper conductor having a cross-sectional area of 0.5 mm ² to a thickness of 0.5 mm to obtain an electric wire. In Example 4 in which electron beam irradiation crosslinking was performed, 5 Mra was used in a separate step.
The insulated wire was obtained by irradiating the electron beam of d.

The insulated wires thus manufactured were subjected to the following characteristic tests, and the results are shown in the lower column of Table 1.

Varnish drying property: An electric wire sample is made of an unsaturated polyester varnish (main material: WP-2952F2G (Y), hardener: CT-38T2, main material / hardener = 100/2 (weight ratio), Hitachi Chemical ( Co., Ltd.)
Curing was performed in a thermostat at 110 ° C. Those dried within one hour under these conditions were rated "good", and those that were sticky without curing were rated "bad". The determination was based on palpation with a finger.

Heat resistance: The heat resistance of the electric wire was judged by the residual elongation ratio due to thermal deterioration. Heating was performed for 20 days in a gear oven at 120 ° C., and those having a residual elongation after heating (%) of 80% or more were accepted.

[0017]

[Table 1]

As is clear from Table 1, Examples 1 to 5 in the range of the antioxidant specified in the present invention have excellent varnish curability and good heat resistance.

On the other hand, Comparative Example 1, which has a composition containing a conventional lead stabilizer, does not inhibit varnish hardening and has good heat resistance. However, since it contains lead, there is a problem of environmental pollution. Comparative Example 2 has a composition in which the added amount of the antioxidant exceeds 0.1%, and is inferior in the curability of the varnish.

[0020]

As described above, the polyvinyl chloride resin composition in which the phenolic antioxidant falls within the range specified in the present invention has not only heat resistance but also no environmental pollution and cures the unsaturated polyester varnish. Excellent in nature,
Its industrial value is extremely high.

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Claims (2)

[Claims] A phenolic antioxidant having a content of 0.1
What is claimed is: 1. A polyvinyl chloride resin composition characterized by being not more than 10% by weight, stabilized with a non-lead-based stabilizer, and containing no lead. 2. An insulated wire, wherein an insulator around the conductor is made of the polyvinyl chloride resin composition according to claim 1.