JPH0559239A - Polyvinyl chloride resin composition and tape wire - Google Patents

Abstract

PURPOSE:To provide the title compsn. which is cross-linked by ionizing radiation such as electron beams or gamma-rays at a high efficiency to give a cross-linked article excellent in flexibility, and a tape wire which is insulated with the compsn. CONSTITUTION:The title compsn. is prepd. by compounding a polyvinyl chloride resin with at least one copolymer selected from the group consisting of an ethylene-vinyl acetate copolymer having a vinyl acetate content of at least 10wt.%, an ethylene-vinyl acetate-acrylic acid copolymer, an ethylene-vinyl acetate-carbon monoxide copolymer, and an ethylene-alkyl (meth)acrylate-carbon monoxide copolymer, and a functional monomer having a (meth)acrylic group, and is used for insulating a tape wire.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyvinyl chloride resin composition, and more specifically, a polyvinyl chloride resin composition suitable as a resin material for an insulating base material of a tape wire, and an insulating group containing the resin composition. A tape electric wire used as a material. The resin composition of the present invention has excellent crosslinking efficiency, and
Even after cross-linking, a tape electric wire having excellent flexibility and excellent heat resistance can be obtained when used as an insulating base material.

[0002]

2. Description of the Related Art A multi-core tape electric wire is used as an electric wire for internal wiring of audio equipment, office automation equipment and the like. This tape electric wire usually has a structure in which a plurality of conductors are sandwiched between two insulating base materials.

A cross-linked tape electric wire is one of such tape electric wires. In this crosslinked tape electric wire, an insulating base material made of synthetic resin is crosslinked in order to improve heat resistance. A flame-retardant polyvinyl chloride resin (PVC) is often used as a resin material for forming an insulating base material of a tape electric wire, but a cross-linked tape electric wire also uses a PVC material as an insulating base material ( Japanese Patent Publication 60-4884
4 publication). As a method for crosslinking PVC, a monomer (crosslinking aid) having a functional group such as trimethylolpropane tri (meth) acrylate or triallyl (iso) cyanurate is added and irradiated with ionizing radiation such as electron beam or γ ray. Or a chemical crosslinking method using an organic peroxide is known, but in the case of a crosslinked tape electric wire using PVC as an insulating base material, a crosslinking method by irradiation with ionizing radiation is generally adopted. ..

However, in the case of irradiating and cross-linking PVC, if the irradiation dose becomes too large, the deterioration of PVC also progresses, and the PVC becomes brittle. Further, when the amount of the crosslinking aid added is too large in order to sufficiently crosslink with a small irradiation dose, the PVC after crosslinking becomes hard and often breaks when bent. As described above, when the crosslinked PVC is used as the insulating base material of the tape electric wire, it is difficult to adjust the irradiation dose and the addition amount of the crosslinking auxiliary, and when the crosslinking is insufficient, the heat resistance improving effect is small and In addition, if the irradiation dose or the amount of the crosslinking aid added is increased too much, it deteriorates or becomes hard, and cracks are likely to occur when the insulating portion is bent.

[0005]

DISCLOSURE OF THE INVENTION An object of the present invention is to provide a polyvinyl chloride resin composition which is excellent in cross-linking efficiency by ionizing radiation such as electron beams and γ-rays and which is also flexible after cross-linking. To do. Moreover, the objective of this invention is providing the tape electric wire which used such a resin composition as an insulating base material.

The present inventor has conducted extensive studies in order to overcome the problems of the above-mentioned prior art, and as a result, PVC is provided with a specific copolymer and a functional monomer containing a (meth) acrylic group as a crosslinking aid. It has been found that the resin composition contained therein efficiently crosslinks even with a small irradiation dose and retains sufficient flexibility even after irradiation. And, a tape electric wire using this resin composition as an insulating base material has a stable degree of crosslinking and flexibility regardless of the irradiation dose, and becomes an excellent crosslinked tape electric wire which does not cause cracks due to bending. I found it. The present invention has been completed based on these findings.

[0007]

Thus, according to the present invention, (a) is added to 100 parts by weight of polyvinyl chloride resin.
Ethylene-vinyl acetate copolymer having a vinyl acetate content of 10% by weight or more, (b) ethylene-vinyl acetate-acrylic acid copolymer, (c) ethylene-vinyl acetate-carbon monoxide copolymer, and (d) 5 to 50 parts by weight of at least one copolymer selected from the group consisting of ethylene-alkyl (meth) acrylate-carbon monoxide copolymer, and 0.5 to 10 functional monomer containing a (meth) acrylic group.
Provided is a polyvinyl chloride resin composition characterized by containing parts by weight.

Further, according to the present invention, a plurality of conductors are connected to each other.
In a tape electric wire sandwiched between a plurality of insulating base materials, there is provided a tape electric wire using the above polyvinyl chloride resin composition as a resin material forming the insulating base material.

The present invention will be described in detail below. Examples of PVC used in the present invention include homopolymers of vinyl chloride monomers, copolymers of vinyl chloride monomers with other monomers copolymerizable therewith, or mixtures thereof. .. Other monomers include α-olefins such as ethylene and propylene; vinyl esters such as vinyl acetate and vinyl propionate; unsaturated carboxylic acids such as acrylic acid; unsaturated nitriles such as acrylonitrile; vinyl methyl ether, etc. And vinylidene such as vinyldene chloride; and the like. These comonomers are usually used in the range of 30% by weight or less.

The PVC used in the present invention has an average degree of polymerization of 9
Those having a relatively high degree of polymerization of 00 or more are preferred. The ethylene-vinyl acetate copolymer (EVA) used in the present invention is
It is a polymer having a vinyl acetate content of 10% by weight or more.
The preferred range of vinyl acetate content is 10 to 60% by weight.
And more preferably 15 to 40% by weight. When an ethylene-vinyl acetate copolymer having a vinyl acetate content of less than 10% by weight is used, both the crosslinking efficiency by the ionizing radiation and the flexibility of the crosslinked product decrease.

The ethylene-vinyl acetate used in the present invention
The acrylic acid copolymer having a total content of vinyl acetate and acrylic acid of 10% by weight or more is preferable from the viewpoint of crosslinking efficiency and flexibility of the crosslinked product.

The ethylene-vinyl acetate used in the present invention
The carbon monoxide copolymer preferably has a total content of vinyl acetate and carbon monoxide of 10% by weight or more. If this content is less than 10% by weight, the crosslinking efficiency and the flexibility of the crosslinked product decrease.

The ethylene-alkyl (meth) acrylate-carbon monoxide copolymer used in the present invention has a total content of alkyl (meth) acrylate and carbon monoxide of 1 or less.
It is preferably 0% by weight or more. If this content is less than 10% by weight, the crosslinking efficiency and the flexibility of the crosslinked product decrease. Examples of the alkyl (meth) acrylate include methyl acrylate, methyl methacrylate, ethyl acrylate and the like.

The blending ratio of these copolymers is 5 to 50 parts by weight, preferably 5 to 30 parts by weight, based on 100 parts by weight of the vinyl chloride resin. If the blending ratio is too small, the crosslinking efficiency is low and a sufficient crosslinked product cannot be obtained. On the other hand, if the amount is too large, the flame retardancy is lowered, which is not preferable.

The functional monomer containing a (meth) acryl group is preferably one containing two or more functional groups,
For example, trimethylolpropane trimethacrylate,
Examples include trimethylolpropane triacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, and the like. These polyfunctional monomers may be used alone or in combination of two or more. The mixing ratio is 0.5 to 10 parts by weight, preferably 1 to 5 parts by weight, based on 100 parts by weight of the polyvinyl chloride resin. If this blending ratio is less than 0.5 parts by weight, the degree of crosslinking (gelation) will not be sufficient, and if it exceeds 10 parts by weight, the flexibility of the crosslinked product will decrease.

In the resin composition of the present invention, if necessary,
Additives such as plasticizers, heat stabilizers, ultraviolet absorbers, antioxidants, flame retardants, lubricants, colorants, and various organic / inorganic fillers can be added. When used as an insulating base material for a tape electric wire, usually DOP (di-2-ethylhexyl phthalate), DINP (diisononyl phthalate),
DUC (diundecyl phthalate), DOA (di-2-ethylhexyl adipate), trimellitic acid ester,
It is preferable to make a soft PVC by adding a plasticizer such as a phosphate ester. ￣) ^ 0￣ ■】 ■■■■
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The polyvinyl chloride resin composition of the present invention is shaped into, for example, a sheet, and then electron beam, α ray, β
It can be crosslinked by irradiating ionizing radiation such as rays and γ rays. By irradiation cross-linking, a cross-linked product having good cross-linking efficiency, a constant degree of cross-linking, and excellent flexibility can be obtained regardless of the irradiation dose. Therefore, the composition of the present invention is particularly suitable as a resin material for a crosslinked insulating base material of a tape electric wire.

[0019]

In the system in which EVA is added to PVC, the crosslinking efficiency is improved, but with this alone, the physical properties aimed at by the present invention, that is, sufficient gel content (crosslinking degree) can be obtained with a small irradiation dose,
Moreover, a resin composition that retains sufficient flexibility even after crosslinking cannot be obtained. EVA with a vinyl acetate content of 10% by weight or more
Is added in an amount of 5 parts by weight or more, and a functional monomer containing a (meth) acrylic group is used as a crosslinking aid in an amount of 0.5 to 1
The object can be achieved only when 0 part by weight is added. When EVA having a vinyl acetate content of less than 10% is used, satisfactory crosslinking efficiency and flexibility cannot be obtained. Even if the vinyl acetate content is 10% by weight or more, if the blending ratio is less than 5 parts by weight, a sufficient gel content cannot be obtained.

If ethylene-vinyl acetate-acrylic acid copolymer, ethylene-vinyl acetate-carbon monoxide copolymer or ethylene-alkyl (meth) acrylate-carbon monoxide copolymer is used instead of EVA, poly Since the compatibility with vinyl chloride is good, the mechanical properties (elongation, tensile strength) of the resin composition are improved, and it is more effective in imparting flexibility.

As for the cross-linking aid, if a substance other than a functional monomer containing a (meth) acrylic group, such as triallyl (iso) cyanurate, is used, a sufficient gel content cannot be obtained. As for the cross-linking aid, if a monomer other than a (meth) acrylic group-containing monomer is used, for example, triallyl (iso) cyanurate, a sufficient gel content cannot be obtained, and a functional group containing a (meth) acrylic group is not obtained. Even if a polymerizable monomer is used, if the blending ratio is less than 0.5 parts by weight, the gel content is not sufficient, and if it exceeds 10 parts by weight, the flexibility after crosslinking is poor. In this way, combining the characteristic components,
The intended purpose can be achieved only by setting a specific mixing ratio.

[0022]

The present invention will be described in detail below with reference to examples and comparative examples, but these do not limit the scope of the present invention.

[Examples 1 to 5 and Comparative Examples 1 to 3] Sheets having a thickness of 0.3 mm were prepared by the formulation shown in Table 1,
Then, using this sheet, a test tape electric wire having a sectional structure shown in FIG. 1 was prepared. The conductor 1 in FIG. 1 is a copper wire having a diameter of 0.4 mm, and the laminated tape was prepared by sandwiching the copper wire with the insulating base materials 2 and 3 made of the sheet.

These tape electric wires were irradiated with an electron beam to prepare samples for evaluation. Regarding the evaluation method, with respect to the crosslinking efficiency, if the gel fraction was 50% or more by irradiation with 5 Mrad, it was judged as pass (◯), and less than 50% was judged as fail (x). Regarding the flexibility of the crosslinked product, after irradiation of 20 Mrad, 10 points of 180 ° bending test was performed along the conductor on the part a of FIG. 1 as shown in FIG. 2, and if there was no crack at all, it passed (○) and even 1 point. If there was a crack, it was judged as rejected (x). Further, after irradiating with an electron beam of 20 Mrad, a 180 ° bending test was similarly performed on 10 points along the conductor, and the number of cracks was counted. The results are collectively shown in Table 1.

Example 1 is a PVC having an average degree of polymerization of 1000.
100 parts by weight of EVA (vinyl acetate content 20
% By weight), 50 parts by weight of DOP, and 2 parts of trimethylolpropane trimethacrylate as a crosslinking aid.
In this system, 5 parts by weight of flame retardant and 5 parts by weight of heat stabilizer are added.

Example 2 is a system in which the amount of the crosslinking aid of Example 1 is increased from 2 to 5 parts by weight, and Example 3 is a system of Example 1.
Is a system in which the EVA of Example 1 is replaced by an ethylene-vinyl acetate-acrylic acid copolymer, and Example 4 is a system in which the EVA of Example 1 is replaced by an ethylene-vinyl acetate-carbon monoxide copolymer. Example 5 is a system in which the EVA of Example 1 is replaced by an ethylene-alkyl (meth) acrylate-carbon monoxide copolymer.

As is clear from Table 1, the above-mentioned Example 1
Each of the tape electric wires using the resin composition of Nos. 5 to 5 as an insulating base material has a gel fraction of 50% or more upon irradiation with 5 Mrad, has very good crosslinking efficiency, and has 20 Mrad.
It does not generate bending cracks after irradiation and has excellent flexibility.

Comparative Example 1 is a system obtained by removing EVA from Example 1, which has a gel fraction as low as about 40%, and bending cracks are observed after irradiation. Comparative Example 2 is a system in which trimethylolpropane trimethacrylate, which is the crosslinking aid of Example 2, is omitted, but the gel fraction is about 40%, which is insufficient. Further, Comparative Example 3 is a system in which the crosslinking aid of Example 2 is changed from trimethylolpropane trimethacrylate to triallyl isocyanurate,
Bending cracks did not occur in this, but the gel fraction was not sufficient.

[0029]

[Table 1]

(* 1) Vinyl acetate content 20% by weight, melt index 25 g / 10 minutes (190 ° C., 2.1
6 kg) (* 2) Vinyl acetate content 15% by weight, acrylic acid content 5
% By weight, melt index 20 g / 10 minutes (190
(° C, 2.16 kg) (* 3) Vinyl acetate content 19% by weight, carbon monoxide content 6
% By weight, melt index 25 g / min (190 ° C.,
2.16 kg) (* 4) Ethyl acrylate content 19% by weight, carbon monoxide content 6% by weight, melt index 25 g / min (19
0 ℃, 2.16kg)

[0031]

EFFECTS OF THE INVENTION According to the present invention, it is possible to provide a polyvinyl chloride resin composition which is excellent in cross-linking efficiency in irradiation cross-linking with ionizing radiation and has good flexibility of the cross-linked product. Therefore, if the composition of the present invention is used as an insulating base material for tape electric wires, regardless of the amount of irradiation,
It can have a stable degree of crosslinking and flexibility.

[Brief description of drawings]

FIG. 1 is a view showing a cross-sectional structure of a test tape electric wire.

FIG. 2 is a diagram showing a bending test.

[Explanation of symbols]

 1 conductor 2 base material 3 base material a bent portion

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical indication C08L 73/00 LQQ 9167-4J H01B 7/08 7244-5G

Claims (2)

[Claims] 1. Ethylene containing (a) a vinyl acetate content of 10% by weight or more based on 100 parts by weight of a polyvinyl chloride resin.
Vinyl acetate copolymer, (b) ethylene-vinyl acetate-acrylic acid copolymer, (c) ethylene-vinyl acetate-carbon monoxide copolymer, and (d) ethylene-alkyl (meth) acrylate-carbon monoxide copolymer. 5 to 50 parts by weight of at least one copolymer selected from the group consisting of polymers, and a functional monomer containing a (meth) acrylic group.
A polyvinyl chloride resin composition comprising 5 to 10 parts by weight. 2. A tape using a polyvinyl chloride resin composition according to claim 1, as a resin material forming the insulating base material in a tape electric wire formed by sandwiching a plurality of conductors between two insulating base materials. Electrical wire.