JPS61190807A - Insulation film - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an insulating film, and more particularly to an insulating film having heat resistance and solvent resistance.

[Conventional Technique 11] Conventionally, mica paper, varnish cloth, etc. have been used to insulate various electrical machines, such as generators and transformers, but in recent years, plastic films have gradually come to be used. Typical examples of such plastic films include polyethylene, polypropylene, polycarbonate,
Polyfluorinated ethylene, polystyrene, polyvinyl chloride,
Films such as polyethylene terephthalate are known.

Although polyethylene film has excellent electrical properties, it has poor heat resistance, and its maximum allowable temperature is 90°C. Polycarbonate film can be used up to high temperatures,
Tetrafluoroethylene is known as a polyfluoroethylene film that is superior to polyester film but has poor solvent resistance. It has a very high heat resistance temperature of <250℃, and has a small dielectric loss tangent and excellent electrical properties.
It has poor processability, making it difficult to produce a uniform thin film, has poor surface adhesion, and is very expensive. Polystyrene film has excellent dielectric properties and has been used in capacitors for communication equipment, but it has poor heat resistance and is brittle. Polyvinyl chloride film is mainly used as black tape for insulating electrical wire connections. However, it has poor heat resistance and becomes brittle due to the embossment of plasticizer. Both polypropylene film and polyethylene terephthalate film are biaxially stretched and have excellent mechanical and electrical properties.
Heat resistance is not comparable to fluororesin.

[Problems to be Solved by the Invention] However, when the various plastic films described above are used as insulating films or tapes, they are all poor in heat resistance due to their thermoplasticity.

It also has the disadvantage of poor solvent resistance.

The technical object of the present invention is to provide an insulating film that has improved heat resistance and solvent resistance, which are disadvantages of conventional thermoplastics.

[Means for solving the problem] As a result of intensive research to solve the above problem, the present inventor has found that
A film made of thermoset polyurethane has heat resistance,
The present invention was achieved by discovering a scale that provides an insulating film with excellent solvent resistance. That is, the insulating film according to the present invention is characterized in that the base resin is a thermoset polyurethane resin.

The present invention will be explained in detail below.

In the present invention, the polyurethane resin necessary for producing the insulating film consists of a high molecular weight polyhydric hydroxy compound, a low molecular weight active hydrogen compound, and an organic isocyanate.

As a high molecular weight polyhydric hydroxy compound, the molecular weight is 300~
5000. Preferably, 500 to 3000 polyether polyols, polyester polyols, or mixtures thereof are used. Examples of polyether polyols include polypropylene glycol, polyethylene glycol, polytetramethylene ether glycol, and the like. Polyester polyols are produced from polyhydric carboxylic acids and polyhydric alcohols. Examples of polyhydric carboxylic acids include adipic acid, sepathic acid, isophthalic acid, and terephthalic acid. Examples of polyhydric alcohols include ethylene glycol, propylene glycol, bentanediol, hexanediol, neopentyl glycol, glycerin, trimethylolpropane, and pentol. When used, these may be used alone or in combination.

Examples of the low molecular weight active hydrogen compound include amine compounds such as ethylene diamine, hexamethylene diamine, inphorone diamine, and diaminodiphenylmethane, in addition to the above-mentioned polyhydric alcohol compounds, and these may be used alone or in combination.

Examples of the organic isocyanate compound include aromatic or alicyclic diisocyanates or mixtures thereof. Examples of these include tolylene diisocyanate, metaphenylene diisocyanate, naphthylene diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, lysine isocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, etc., and these may be used alone or in combination.

These compounds are used as raw materials by a solvent method or a non-solvent method so that the ratio of the number of moles of incyanate to the number of moles of total active hydrogen is in the range of 1.05:1.0 to 2.0:1.0. BO℃~150℃, preferably 80℃~1
The reaction is carried out at a reaction temperature of 20° C. for 10 minutes to 10 hours to obtain a urethane prepolymer.

When using a solvent, examples of usable solvents include aromatic solvents such as toluene and xylene, ester solvents such as ethyl acetate and butyl acetate, ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, and cyclohexane, and dimethyl formamide. Examples include amide solvents.

A high molecular weight polyhydric hydroxy compound or a low molecular weight active hydrogen compound is added to the urethane prepolymer obtained as described above so that the ratio of incyanate groups to total active hydrogen groups is 1.0.
: 0.1 to t, o : 1.1 to produce a thermoset polyurethane resin, that is, the insulating film of the present invention. At this time, a catalyst may be added to promote the curing reaction.
Acids, bases, various metal compounds, etc. are effective, such as triethylamine, triethylenediamine, tin octoate,
dibutyltin dilaurate, lead 2-ethylhexoate,
Potassium oleate, 2-ethylhexyl titanate, tin chloride, iron chloride, iron 2-ethylhexoate, antimony trichloride, and the like may be used alone or in combination. Note that the amount of catalyst added is preferably about 0.01 to 5% by weight.

Our insulating film is usually made of a polyurethane resin consisting of a urethane polymer, an active hydrogen compound, and a catalyst dissolved in a solvent, and then dried using a roll coater, knife coater, etc. on paper, metal, or plastic film that has been subjected to a release process!
Apply so that the thickness is in the range of 10 layers to 200 μm,
3~BO by drying oven in the range of 60℃~200℃
Obtained by heating and curing for minutes. The curing time can be freely selected depending on the drying oven temperature and the amount of catalyst.

In use, the film can also be slit and used as a tape. It is also possible and more preferable to apply a pressure-sensitive adhesive or an adhesive as necessary.

[Example] The present invention will be explained below with reference to Examples.

Example l Hydroxyl-terminated polyester obtained from neopentyl glycol and adipic acid (molecular weight 2000) 1000)
70 parts by weight, 15 parts by weight of trimethylolpropane, 100 parts by weight of tolylene diisocyanate, Kijirol 3
0 parts by weight, cellosolve acetate) 30 parts by weight with a thermometer,
The NGO
A prepolymer with a content of 8.5% by weight was obtained.

PE45G (manufactured by Mitsui Nisso Polyurethane Co., Ltd.) was used as a polyol component for 100 parts by weight of this prepolymer.

25 parts by weight of (trade name, OH value 450) and 0.2 parts by weight of dibutyltin dilaurate as a catalyst were added to a release-treated polyethylene terephthalate film using a knife coater to give a dry film thickness of 501 Lm to 100 p.m. 100"0 to 14Q"O in a drying oven.
Table 1: Polyurethane film obtained by heating and curing for 0 minutes
Shows electrical properties, heat resistance, and solvent resistance.

As a method for evaluating electrical properties, surface resistivity is determined using JIS C
-2330, for permittivity and dielectric loss tangent ^STM
Evaluation was made according to 0-150. The heat resistance was evaluated by heat shrinkage rate. Specifically, 74 /L/
After immersing the film in a silicone bath set at temperatures of 100°C, 150°C, and 200°C for 10 minutes, the shrinkage rate in the film pulling direction was determined. Solvent resistance was evaluated by weight change after being immersed in various solvents at 23° C. for one week.

Example 2 18 parts by weight of hydroxyl-terminated polyester (molecular weight 2000) obtained from neopentyl glycol and adipic acid, 18 parts by weight of polypropylene glycol (molecular weight 1000)
parts by weight, parts by weight of trimethylolpropane B, 40 parts by weight of isophorone diincyanate, 2 parts by weight of cellosolve acetate
0 parts by weight was placed in a four-bottle flask equipped with a thermometer and a stirrer, heated while adding nitrogen, and reacted for 4 hours at 75°C to 80°C to obtain a prepolymer with an NGO content of 7.6% by weight. .

To 100 parts by weight of this prepolymer, 8 parts by weight of PE450 (manufactured by Mitsui Nisso Polyurethane Co., Ltd., trade name, OH value 450) as a polyol component and 8 parts by weight of dibutyltin dilaurate as a catalyst were blended, and mold release treatment was performed. It was coated onto a polyethylene terephthalate film using a knife coater to a dry film thickness of 50 gm to 100%, and heated and cured in a drying oven at 100'C! to 140'O for 10 minutes to obtain a polyurethane film.

Table 1 shows the electrical properties, heat resistance, and solvent resistance.

Comparative Examples 1 to 3 As Comparative Examples 1 to 3, the electrical properties, heat resistance, and solvent resistance of polyvinyl chloride film (Comparative Example 1), polyethylene film (Comparative Example 2), and polycarbonate film (Comparative Example 3) are shown in Table 1. Listed below.

As is clear from Table 1, all of the comparative examples are inferior to Examples 1 and 2 in heat resistance and solvent resistance.

Margins below [Effects of the Invention] According to the present invention, an insulating film characterized in that the base resin is a thermoset polyurethane resin has superior heat resistance and solvent resistance compared to conventional thermoplastic films. It has great practical value.

Claims (1)

[Claims] An insulating film characterized in that the base resin is a thermoset polyurethane resin.