JPS587004B2 - Seizouhouhou - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Conventionally, in the production of thin-walled insulated wires such as magnet wires with a thickness of 0.1 mm or less, an insulating paint made by dissolving a resin in an organic solvent is usually applied on the conductor 5 to 10 times. It is dried and solidified.

With this method, any resin that dissolves in a solvent can be applied, and it is still widely used today because it produces a coating film with a uniform finish.
It is extremely slow (about 1/2 minute) and generates harmful organic solvent waste gas during baking, so improvements have been desired.

On the other hand, for thin electric wires such as the core of communication cables, insulating coatings are formed by extrusion, and in this case, wire speeds of several 100 m/min are possible, but the resin that can be extruded is limited. It was getting worse.

Furthermore, attempts have been made to extrude and coat the conductor with a thin layer of high-strength, low-melt-viscosity resin such as polyester, but this method lacks mechanical strength including abrasion resistance and heat deterioration resistance, and is not compliant with JIS standards. It was impossible to obtain an insulated wire that met the standards.

The present invention has been made to solve these conventional problems, and involves extruding a mixture of a polyester resin having two or more unterminated carboxyl groups and a trihydric or higher polyhydric alcohol onto a conductor to form a coating. , relates to a method for manufacturing an insulated wire, which is characterized by subjecting the wire to a heating reaction.

Polyester resins having two or more unterminated carboxyl groups used in the present invention include polyester resins, polyester imide resins, polyester amide imide resins, and various modified polyester resins.

Any of these polyester resins can be used as long as they have two or more unterminated carboxyl groups and can undergo condensation polymerization with trihydric or higher polyhydric alcohols, but if a large amount of carboxyl groups remain in the final coating, it will become a conductor. On the other hand, if a large amount of hydroxyl groups remain, the water resistance of the coating will decrease. Therefore, when a polyhydric alcohol with a valence of 3 or more is added, one of the carboxyl groups and the hydroxyl groups as a whole is 20%, preferably 10%. It is desirable that the composition be made from a composition that results in an excess of within about %.

Polyester resins suitable for the present invention are those synthesized from aromatic dicarboxylic acids, tricarboxylic acids, or tetracarboxylic acids and excess amounts of diols and triols.

At this time, if the starting material has an imide ring in its molecular structure, a coating with excellent heat resistance can be obtained.

The production of such a polyester resin is carried out, for example, as follows.

That is, an aromatic carboxylic acid such as dimethyl terephthalate or its derivative, a primary diol such as ethylene glycol, and optionally a trihydric or higher alcohol such as trimethylolpropane are reacted for 6 to 9 hours at room temperature or with heating. let

At this time, in order to increase the rate of transesterification reaction, lead oxide,
Lead naphthenate, zinc acetate, etc. may be added as a catalyst, and cresol, xylenol, solvent naphtha, etc. may be added in advance to lower the viscosity of the reaction product and prevent volatilization of the starting materials.

These solvents such as cresol are distilled out together with reaction by-products due to heating during the reaction.

The reaction product is heated to the required final temperature from room temperature to approximately 250°C to bring the reaction to an equilibrium state. At this time, the polyester resin formed is to be as high in molecular weight as possible without gelling. Heat to achieve substantially complete reaction.

Examples of trivalent or higher alcohols used in the present invention include primary and There are secondary dihydric and trihydric alcohols, and primary alcohols are particularly suitable from the viewpoint of reactivity.

It is desirable that the amount of these trihydric or higher alcohols is 5 to 30 equivalents of the total alcohol component.

If the amount of these alcohols added exceeds 10% by weight of the fusible synthetic resin, slippage will occur especially on the screw during extrusion, so if a large amount is used, add the alcohol to the starting material of the polyester resin. Some need to be used.

Furthermore, in the present invention, by allowing a small amount of a polycondensation catalyst to exist in these compositions, the heating reaction can be accelerated, and therefore the manufacturing line speed can be improved.

As such a catalyst, lead naphthenate, zinc naphthenate, etc. may be used, but titanium chelate compounds are particularly suitable.

The titanium chelate compounds used in the present invention include triethanolamine titanate (TEAT), lactic acid stabilized TEAT, TEAT to which oleic acid, stearic acid, and linoleic acid are added, oxylene glycol titanate (OGT), and tetraisopropylene. Pilticunate (TIP)
T), Tetrabutyltichnate (TET), Tetler 2
-Ethylhexylticunate (TEHT) and the like.

These titanium chelate compounds are added to a synthetic resin powder together with a polyhydric alcohol having a valence of 3 or more, and are used after being uniformly mixed.

Note that titanium chelate compounds are soluble in water and alcohol, so a mixture of polyester resin and tetracarboxylic acid, etc. is extruded onto the conductor, and the conductor is inserted into the solution while it is hot to cause a heating reaction. You may also do so.

In this case, the titanium chelate compound penetrates into the coating and promotes the crosslinking reaction, especially near the surface.

In addition, if amines are added to the aqueous solution of the titanium chelate compound, they will react with excess carboxyl groups in the coating molecules during the heating reaction step and mask the active carboxyl groups, thereby reducing the amount of coating caused by free carboxyl groups. Can remove corrosive properties.

Such amines include monoethanolamine,
Examples include diethanolamine, triethanolamine, amino alcohol, morpholin, N-methylmorpholin, and the like.

In carrying out the present invention, first, a polyester resin, a trivalent or higher polyhydric alcohol, and a titanium chelate compound are thoroughly mixed, and this is fed to a normal screw type extruder and extruded onto a conductor by a conventional method. Cover.

Next, the extruded insulated wire is passed through a baking furnace at 350 to 450°C, and at this stage the polyhydric alcohol in the coating reacts with the unterminated carboxyl groups in the polyester resin, creating a crosslinked structure in the resin molecule. form and make the coating infusible and insoluble.

Note that if a polymerization catalyst such as a titanium chelate compound is not added during extrusion, a polymerization catalyst solution is applied to the surface of the coating during the process of entering the baking oven after extrusion.

The polymerization catalyst acts as a polycondensation catalyst for tetracarboxylic acid and polyester resin.

According to the present invention, 10 to 20 m/
It is now possible to manufacture insulated wires having properties equivalent to those of insulated wires that have been manufactured at wire speeds of about 100 m/min or more.

In particular, in the present invention, since the trihydric or higher polyhydric alcohol acts as a lubricant during extrusion, there is no problem such as early crosslinking (staining) during extrusion, and a smooth coating is formed. There is almost no foaming or appearance defects that occur during conventional paint baking.

Next, examples will be described.

Example 1 Dimethyl terephucrate 1165.2 g (6 mol), ethylene glycol 310.4 g (5 mol), THEIC1
30.6g (0.5mol) to 150g of solvent naphtha
and 3 g of lead naphthenate in a three-necked flask.
The reaction was carried out at 170° C. for 5 hours while by-produced methanol and the like were distilled out together with the solvent naphtha, and then the reaction was further carried out at 220° C. for 2 hours while reducing the pressure.

After that, the reaction temperature was lowered to 170℃ and
0.1 mol of '-benzophenonetetracarboxylic dianhydride was gradually added and allowed to react until completely dissolved.

After the reaction was completed, the product was cooled to room temperature, and the resulting pale brown resin with a softening point of about 56°C was pulverized into a powder of 100 mesh or less using a ball mill.

The powdered polyester resin thus obtained was added to 67 g (0.
．． 5 mol) of trimethylol and 12 g of TEA
T is uniformly mixed while heating, and this mixed resin is supplied to a normal screw type extruder, and the diameter is 1.
．． It was extruded onto a 0 mm annealed copper wire to a thickness of 50 μm, and then passed through a baking furnace at 450° C. to obtain an insulated wire.

The test results for this insulated wire were as follows.

Bin holes (pcs/5m) 0 self-diameter winding Good wear resistance (times)
[Load 700g] 45 Breakdown voltage (KV)
13.4 Softening temperature [1 point intersection 80
0g load] (°C) 310 Example 2 4 moles of dimethyl terephucrate and 6 moles of ethylene glycol were added to 150 g of solvent naphtha and 3 g of lead naphthenate.
The mixture was placed in a three-necked flask and reacted at 170°C for 6 hours, then the temperature was raised to 230°C for 3 hours.

After that, the reaction temperature was lowered to 170℃, and 3, 3', 4, 4
'-Benzphenonetetracarboxylic dianhydride 1.75
mol was gradually added, and when it was completely dissolved, the reaction system was rapidly cooled, and the resulting resin was made into a powder of 100 mesh or less using a ball mill.

Next, while heating this powder,
The mixed resin was extruded in the same manner as in Example 1, passed through an aqueous solution of TEAT, and then inserted into a baking furnace at 450° C. to obtain an insulated wire.

The test results for this insulated wire are shown below.

Claims (1)

[Claims] 1. A coating is formed by extruding a mixture of a polyester resin having two or more unterminated carboxyl groups and a trihydric or higher polyhydric alcohol onto a conductor, and the coating is heated and reacted. A method of manufacturing an insulated wire. 2. When extruding a mixture of a polyester resin having two or more unfinished carboxyl groups and a trihydric or higher polyhydric alcohol onto a conductor to form a coating, and subjecting this to a heating reaction, at least A method for manufacturing an insulated wire, characterized in that a titanium chelate compound of 0.01 to 5% (in terms of Ti content) based on the resin content is present near the surface.