JPS581484B2 - Curl cord coated with polyester elastomer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to electrical wires coated with polyester elastomers.

More specifically, the present invention relates to a covered wire made of a copolyester ether elastomer having a specific composition.

In addition to being used for general wiring in the form of a wire, coated wire is also used as a curled cord made by winding the coated wire in a spiral shape and heat-setting it for use as a curl cord for telephone wires, microphones, stereo headphones, electric razors, etc. A considerable amount is used.

Conventionally, natural rubber, synthetic rubber, polyvinyl chloride, polyethylene, polypropylene, nylon, etc. have been widely used as covering materials for electric wires, but these covering materials have the following problems.

For example, when rubber is used as a coating material for general wiring covered electric wires, a curing process is required, and when synthetic resin is used, increasing the coating speed will result in poor coating, which significantly limits productivity.

In curl cords, the rubber is easily affected by heat,
Especially in sunny places such as inside a car, the cord's shape retention is poor and the cord loses its curl retention due to its own weight.

Also, since the synthetic resin coated curl cord is hard, it has considerable resistance to stretching during use.

Force to stretch and return to original state? In order to soften the curl cord, for example, plasticized polyvinyl chloride is used to soften the expansion and contraction of the curl cord.

However, the plasticized polyvinyl chloride-coated curl cord does not have sufficient elasticity and has poor curl retention, so the coating layer must be thick.

For this reason, it gives a heavy feeling when used and cannot form thin curl cords, which is extremely limiting as a product.

It has been found that polyester ether elastomer is an excellent new material that does not have the drawbacks of conventional materials and can be melt-molded, leading to the present invention.

The present invention is made essentially of units derived from a polyalkylene glycol having an average molecular weight of 350 to 6,000 and a ratio of carbon number to oxygen number of 2 to 4.5:1, and terephthalic acid and/or 2.6-naphthalenedicarboxylic acid. and ester units consisting essentially of units derived from a glycol having 2 to 10 carbon atoms and terephthalic acid and/or 2,6-naphthalene dicarboxylic acid, and the ether ester units are It is an electric wire coated with a copolyester ether that accounts for 5 to 85% by weight of the entire wire.

The present invention will be explained.

The copolyester ether in the present invention refers to a copolyester ether consisting essentially of ether ester units and ester units consisting of linear molecules.

The polyalkylene glycol forming the linear ether ester unit is, for example, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polyethylene glycol-polypropylene glycol block copolymer, etc., and these have a carbon number to oxygen number ratio of 2. If the ratio is .0 to 4.5 to 1, it can be used alone or as a mixture.

When the ratio of carbon number to oxygen number exceeds 5 (for example, polyhexamethylene glycol), it is unsuitable as a flexible and highly shape-retentive curl cord covering material.

The average molecular weight of the polyalkylene glycol is 350-6
000, but this is limited to this range due to flexibility as a covering material and ease of molding.

Especially industrially, the molecular weight range is preferably about 600 to 3,000.

Within the scope of the present invention, the alkylene glycol of the foot segment component has good compatibility, and the copolyester ether of the present invention is transparent.

Further, the ether ester unit and the acid component forming the ester unit are substantially terephthalic acid and/or 2,6-naphthalene dicarboxylic acid.

In addition to terephthalic acid or 2,6-naphthalene dicarboxylic acid, a small proportion (15% or less) of other aromatic dicarboxylic acids such as isophthalic acid, adivic acid, sebacic acid,
Aliphatic dicarboxylic acids such as cyclohexane-1,4-dicarboxylic acid may be used in combination.

The present invention uses terephthalic acid or 2 as a hard segment.
．． It uses 6-naphthalene dicarboxylic acid, and provides heat resistance, weather resistance, appropriate elastic modulus (flexibility), and morphological stability through a suitable composition with the soft segment of polyalkylene glycol, and the acid component requires the above-mentioned aromatic dicarboxylic acid.

Furthermore, the glycol component forming the ester unit is a glycol having 2 to 10 carbon atoms, that is, ethylene glycol,
These include propylene glycol, tetramethylene glycol, hexanediol, and decanediol.

These glycols are limited to the above carbon number range due to the flexibility and reactivity of the ester unit.

If the number of carbon atoms is significantly large, the softening point of the coating material will drop, impairing its practicality.

Accordingly, the ether ester unit and the copolyester ether substantially composed of the ester unit used in the present invention are those in which the ether ester unit accounts for 5 to 85% by weight.

When the ether ester unit content is less than 5%, the coating material has extremely low elastic modulus, softening point, and brittle temperature, and loses its shape retention similar to conventional rubbers.

Further, copolyester ether rich in ether ester units exceeding 85% is not preferred because it becomes stiff and loses its usefulness as a curled cord.

Therefore, copolyester ether suitable as a wire coating material has a embrittlement temperature of about minus 40°C, does not crack at low temperatures, and has a softening point of 140°C within a range where the molding speed can be increased.
C or higher, and the ether ester unit is preferably 5 to 85% by weight.

To produce the polyester ether, the acid component,
The glycol component and the polyalkylene glycol component may be polycondensed by any method.

For example, by reacting dimethyl ester of terephthalic acid with a low molecular weight diol and polytetramethylene glycol in the presence of a transesterification catalyst, and then distilling the resulting prepolymer under reduced pressure to remove excess low molecular weight diol. It is produced by a method that produces a high molecular weight copolyester ether polymer.

Of course, it may also be produced by a direct esterification method using terephthalic acid instead of dimethyl ester of terephthalic acid.

The manufacturing method itself may be any method.

Furthermore, heat stabilizers, ultraviolet stabilizers, pigments, optical brighteners, carbon black, etc. can be added to the polyester ether depending on the purpose.

The copolyester ether having the above-described specific composition used in the wire coating material of the present invention can be melt-molded and has excellent curing properties, making it a useful material as a wire coating material.

The wire coating has the advantage that conventionally known molding and the like can be used as is and can be produced at high speed.

Hereinafter, the present invention will be explained in detail with reference to Examples.

In the examples, "parts" mean parts by weight.

The reduced viscosity was measured at 35 DEG C. by dissolving 120 ml of sample polymer in 10 ml of O-chlorophenol.

The polyester elastomer used in the examples was polymerized by the following method.

Dimethyl terephthalate, tetramethylene glycol, polytetramethylene glycol, and tetrapoxy titanate are charged into a reactor equipped with a stirrer, a distillation device, and a nitrogen inlet tube, and heated to 180 to 220°C. After 90% distillation, the temperature was reduced to 240°C.
30 minutes at normal pressure, and then about 30 mmH.
Gabs weak vacuum and react for 30 minutes, then 0.1~
Polymerization was carried out for 200 minutes under high vacuum of 0.3 mmHgabs.

Example 1 The polymer was obtained by the method described in the text.

Dimethyl terephthalate 794 parts Tetramethylene glycol 442 parts Polytetramethylene glycol 100 parts Tetrabutoxy titanate
The 1-part reduced specific viscosity was 1.98.

After drying the obtained polymer at 110°C for 3 hours,
Electric wires each having a thickness of 1.8 mm (four strands combined) were coated to a thickness of 0.4 mm using an extruder.

The electric wire had a withstand voltage of 15,000 volts or more.

Comparative Example 1 A plasticized polyvinyl chloride coated wire having the same thickness as in Example 1 had a dielectric strength ratio of 2000 volts.

Example 2 A polymer was polymerized in the same manner as in Example 1.

Dimethyl terephthalate 617 parts Tetramethylene glycol 344 parts Polytetramethylene glycol 300 parts Tetrabutoxy titanate 0.87 parts The resulting polymer had a reduced specific viscosity of 1.90.

After drying the polymer at 110° C. for 3 hours, it was coated with a 0.5 mm thick electric wire having a thickness of 1.8 mm (four twisted wires) using a 30 mm extruder.

This electric wire was wound around a 18 mm cylinder, both ends of which were fixed, and then heat treated at 160° C. for 20 minutes. After cooling, the wire was removed from the cylinder.

The resulting curled cord was reverse-wound, a weight of 20 g was attached, and the cord was hung in a room at 25° C. for one week to test its elongation.

As a result, almost no elongation was observed.

Comparative Example 2 A plasticized polyvinyl chloride coated electric wire having the same thickness as in Example 2 was heat treated at 160° C. for 20 minutes, but when removed from the cylinder, the curl retention property was lost and a curl cord could not be formed.

Example 3 A polymer was polymerized in the same manner as in Example 1.

Dimethyl terephthalate 441 parts Tetramethylene glycol 245 parts Polytetramethylene glycol 500 parts Tetrapoxy titanate 0.0
The reduced specific viscosity of the polymer obtained in 6 parts was 2.1.

After drying the polymer at 110°C for 3 hours, the temperature of the heater from the hopper opening to the die was set at 210°C using a 30mm extruder.
Bare electric wires (7 cores) with a diameter of 0.6 mm were coated at a coating speed of 200 m/mm at temperatures of 230°C and 240°C.

It was possible to coat with a thickness of 0.075 mm.

It withstood a withstand voltage of 10,000 volts in a spark test, and there were no problems with the coating.

Comparative Example 3 Plasticized polyvinyl chloride, polyethylene, and polypropylene were attempted to be coated to a thickness of 0.075 mm as in Example 3, but some portions were not coated.

Example 4 Using the polymer polymerized in Example 1, a polymer with a thickness of 1.8 mm (
(4 strands) were coated to a thickness of 9.7 m.

This electric wire was wound around a 15 mm cylinder, both ends of which were fixed, and then heat treated at 160° C. for 20 minutes.

After cooling, it was removed from the cylinder.

The resulting curled cord was reverse-wound, a 20 g weight was hung thereon, and curl retention was tested for 8 hours in an oven at 60°C.

As a result, the curl extension was only 2 cm.

Comparative Example 4 Similar to Example 4, an electric wire coated with K-plasticized polyvinyl chloride was wound around a 15 mm cylinder and heat-treated at 130° C. for 20 minutes.

The resulting curled cord was reverse-wound and a 20 g weight was hung thereon for 8 hours in an open environment at 60° C. to test the curl retention property, and the curl elongation was 19 cm.

Claims (1)

[Claims] 1 Substantially 2 from units derived from polyalkylene glycol having an average molecular weight of 350 to 6,000 and a ratio of carbon number to oxygen number of 2.0 to 4.5:1 and terephthalic acid and/or 2.6-naphthalenedicarboxylic acid. and an ester unit consisting essentially of units derived from a glycol having 2 to 10 carbon atoms and terephthalic acid and/or 2,6-naphthalene dicarboxylic acid, and the ether ester The unit is 5 of the whole
Wire coated with copolyester ether comprising ~85% by weight.