JPS60179468A - Electrical insulating polyurethane paint - Google Patents

Abstract

PURPOSE:To provide an electrical insulating paint having a high resin content and excellent solderability, containing a polyol component and a blocked isocyanate component obtd. by reacting a lactam, a phenol and a diisocyanate in a specified ratio. CONSTITUTION:An electrical insulating paint contains a polyol component and a blocked isocyanate component obtd. by reacting a lactam (a) of formula I (wherein n is 1-5), a phenol (b) and a diisocyanate (c) of formula II (wherein R is a bivalent aliph. or arom. hydrocarbon group) in a molar ratio of (a)/(b)=8/2-2/8 and of {(a)+(b)}/(c) 2.0. Xylenol is preferred as the phenol from the viewpoint of paint storage stability. A preferred diisocyanate is diphenylmethane diisocyanate from the viewpoint of heat resistance of insulated wires.

Description

[Detailed description of the invention] The present invention relates to a polyurethane electrical insulation coating.

More specifically, the polyurethane electrical coating provides a polyurethane insulating paint with a high resin concentration, and when used for insulated wires, it provides excellent painting workability, good appearance, and excellent solderability. Regarding insulating paint.

Polyurethane electrical insulation paint has a film that is chemical resistant.
Excellent electrical properties and no peeling of the film.
It has advantages such as being able to be soldered, and is widely used in fields such as household electrical equipment and communication equipment. Generally, polyurethane-based electrical insulation coatings contain a blocked isocyanate component and a polyol component. Conventionally, the blocked isocyanate component is obtained by adding three molecules of diphenylmethanol diisocyanate to one molecule of a triol such as trimethylolpropane, and blocking the free incyanate groups with phenols. Blocked isocyanates are used that are stable at room temperature and dissociate at high temperatures to generate free incyanate groups. The polyol component is obtained by blending a polybasic acid with a diol such as ethylene glycol or propylene glycol, or a triol such as trimethylolpropane or glycerin with an excess of hydroxyl groups, and causing transesterification and condensation reaction. It will be done. A polyester polyol having a terminal hydroxyl group or the like is used.

However, conventional polyurethane-based electrical insulating paints containing these blocked isocyanate components and polyol components have the disadvantage of low resin concentration, and the amount of paint required to produce a unit amount of insulated wire is reduced, resulting in Paints with high non-volatile content are desired from the viewpoint of cost reduction.

Furthermore, from the viewpoint of improving the reliability of electrical equipment and productivity in manufacturing processes, there is a strong demand for the development of electrical insulating paints that provide films with better solderability than before.

As a result of various studies to meet these demands, the present inventors have found that by using a specific block isocyanate as an incyanate component, a paint that supports insulated wires with a high resin concentration and excellent solderability has been developed. The present invention was achieved by discovering that the following can be obtained.

The present invention is based on (a) the general formula CH2CO (where n is (CH
2) Lactams represented by nNH (indicating an integer from 1 to 5).

(b) Phenols and fcl general formula〇CN-几-N
A diisocyanate represented by CO (in the formula R represents a divalent aliphatic or aromatic hydrocarbon group) is prepared by (a)/(
b) = 8/2 to 2/8 (molar ratio), Th, l: H(
fal(bl)/FC) = approx. 2.0 (molar ratio)
The present invention relates to a polyurethane electrically insulating paint containing a polyol component and a blocked isocyanate component obtained by reacting at a ratio of .

Used in the present invention. Examples of the lactams represented by the above general formula include β-propiolactam, r-butyrolactam, and δ-valerolactam.

Epsilon-caprolactam, heptolactam, etc. are used, and these are used alone or as a mixture.

Examples of phenols used include phenol, cresol, xylenol, etc., which may be used alone or as a mixture. Among these compounds, xylenol is particularly preferred from the viewpoint of storage stability of the paint.

The diisocyanate represented by the above general formula is 9
For example, diphenylmethane diisocyanate, tolylene diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, etc. are used, and these are used alone or as a mixture. Among these compounds, diphenylmethane diincyanate is particularly preferred from the viewpoint of heat resistance of the insulated wire.

The usage ratio of these compounds is (a)/(b) = 8
/2 to 2/8 (molar ratio), preferably 6/4 to 2/8, and more preferably 515 to 2/8. Molar ratio is 8/
If it exceeds 2, the insulated wire will become rough and its appearance will deteriorate, and if the trench is less than 2/8, the effect of achieving the objective of the invention will be poor. Also, f fa) + (b) ) / (C) −
The reaction is carried out at a ratio of about 2.0 (molar ratio). It is not strictly necessary to have a molar ratio of 2.0 (it is possible to react at a molar ratio of 1.8 to 2.0 and some free incyanate groups may remain. However, considering the storage stability of the paint, etc. It is better that the free incyanate groups are completely blocked, and for this purpose, the molar ratio should be in the range of 2.0 to 2.2, and the reaction should be carried out with an excess equivalent ratio of active hydrogen groups to incyanate groups. is divine.

The blocked isocyanate component used in the polyurethane electrical insulating paint of the present invention is prepared by heating the +al~(C) component at 120~180°C for 2~7 hours, preferably at 140~180°C.
It is obtained by heating and reacting at 160°C for 3 to 5 hours.

Along with these blocked isocyanate components, a condensate of a polybasic acid and a polyhydric alcohol is used as the polyol component used in the coating material of the present invention.

There are no particular restrictions on the type, and 1) it can be selected from commercially available materials that can react with the incyanate component; and 2) for example, with polybasic acids.

The diol and the triol have a hydroxyl group/carboxyl group equivalent ratio of 1.4 to 2.4. Preferably 1.6-2.
It is possible to use a product obtained by blending at a ratio of 0 and reacting at 200 to 250°C.

Examples of polybasic acids used in this case include phthalic anhydride, inophthalic acid, terephthalic acid, adivic acid, sebacic acid, trimellitic anhydride, pyromellitic anhydride, and esterified products of these acids. Used alone or in mixtures. Examples of diols include ethylene glycol, diethylene glycol,
Propylene glycol, dipropylene glycol, neopentyl glycol, 1,6-hexanediol.

1,4-butanediol, 1,3-butanediol, etc. are used. As the triol, for example, trimethylolpropane, glycerin, tris(2-hydroxyethyl)in cyanurate, etc. are used. These diols or triols are used alone or in mixtures.

As such polyol components, commercially available products include Example L (if Smohen 600, Tesmohen 800 (both manufactured by Bayer), Niraporan 2006 (manufactured by Nippon Polyurethane), etc.

In the polyurethane electrical insulation paint of the present invention.

The blending ratio of the blocked isocyanate component and the polyol component is (blocked isocyanate group of the isocyanate component)/(hydroxyl group of the polyprimary component) in an equivalent ratio of 0.8.
~2.0. Fil is preferably in the range of 0 to 1.2.

The polyurethane-based electrically insulating paint of the present invention contains the above-mentioned specific blocked incyanate component and polyol component, and is used after being dissolved in a suitable solvent.

As the solvent used in this case, those used in 9 ordinary baking paints for electric wires can be used. Examples of the solvent include phenol, cresol, xylenol, etc.; examples of the diluent include evasolbent naphtha, toluene, and quintessence; and 2, usually a mixed solvent of a solvent and a diluent is used.

The coating material of the present invention may further include, if necessary.

Various other ingredients can be included. For example, in order to improve the drying properties of the coating film, metal salts such as naphthenic acid and octenoic acid (for example, Pb, Zn, Mg.

Metal salts such as Mn + Co + Cd + Cu + 8n) can be added within the range of 0.001 to 1.0% by weight (% by weight of metal relative to the amount of resin). Also, the paints of the present invention include polyvinyl formals and polyamides.

Epoxy resins and the like can also be blended in an amount of 0.1 to 10% by weight (based on the amount of resin). Furthermore, the paint of the present invention can be colored in a desired color by adding various dyes and pigments.

The present invention will be explained in detail below.

500 g (2.0 mol) of rumethane diisocyanate
I! Put it in Fujisco and be careful not to generate heat.

The temperature was raised to 150° C. in nitrogen, and the temperature was maintained at 150° C. for 5 hours (effective NCO=M→CH). Obtained blocked isocyanate (A) 2709. Niraporan 2006 (hydroxyl value 400) 1309 manufactured by Nippon Polyurethane Co., Ltd. and 4 g of zinc naphthenate were blended.

It was dissolved in Mixed Elution 600a of cresol/kijirole=6/4 (weight ratio) to obtain a paint having a resin concentration of 40% by weight. The viscosity was 0.62 poise at 30°C.

Example 2 Blocked isocyanate (A) 24 obtained in Example 1
09, Desmohen 5oO manufactured by Bayer (hydroxyl value 290
) 1609 and 4 g of zinc naphthenate to create a mixed solvent of cresol/xylo-ru 6/4 (weight ratio) 60
0g to obtain a paint with a resin content of 40% by weight. The viscosity was 0.68 poise at 30°C.

1 methane diisocyanate 5009 (2.0 mol)
1Pour into a flask and be careful not to generate heat.

The temperature was raised to 150°C in nitrogen, and the mixture was heated at 150°C for 5 hours with isocyanate (Bl 280 ta, Nibolan 20
06.1209 and 4g of zinc naphthenate,
It was dissolved in 600 g of a mixed solvent of cresol/kijirole=6/4 (weight ratio) to obtain a paint having a resin content of 40% by weight. The viscosity was 0.61 poise at 30°C.

Example 4 Blocked isocyanate (B) 25 obtained in Example 3
09, Desmohen 800. Cresol/Kijirol = 6/4 by blending tsog and 4g of zinc naphthenate
(weight ratio) was dissolved in 600 g of a mixed solvent to obtain a paint having a resin concentration of 40% by weight.

The viscosity was 0.70 poise.

Comparative Example 1 Xylenol 3669 (3.0 mol) and 375 g (1.5 mol) of diphenylmethane diisocyanate were placed in a flask and heated to 150°C while being careful not to generate heat.
163 g of blocked isocyanate (C) and 4 g of zinc naphthenate were added.

It was dissolved in 630 g of a mixed solvent of cresol/kijirole=6/4 (weight ratio) to obtain a paint with a nonvolatile content of 37% by weight. The viscosity was 0.61 poise at 30°C.

Comparative Example 2 324 g (3.0 mol) of cresol and diphenylmethanediynyanate 7509 (3.0 mol) were mixed into II!
Put it in a flask and keep it under pressure until it reaches 9 degrees of fever.

After reacting at 150°C for 1 hour, trimethylolpropane 1349 (1.0 mol) was gradually added at 120°C and reacted at 130°C for 5 hours to form blocked isocyanate (D) (effective NC0=10. 4%) zinc acid was blended and dissolved in 650 g of a mixed solvent of cresol/kijirole = 6/4 (weight ratio) to obtain a paint with a non-volatile content of 35%. The viscosity was 0.69 poise at 30°C.

Test example Paints obtained in Examples 1 to 4 and Comparative Examples 1 to 2.

A wire speed of 150 m/m was applied to a 0.1 mmφ copper wire according to the usual method.
A polyurethane insulated wire was obtained by repeating 6 times of coating at a temperature of 360/A and baking at a baking temperature of 360/A. Table 1 shows the characteristic values of the obtained insulated wire.

As is clear from Table 1, the electrical insulating paint according to the present invention has a higher resin concentration than the conventional technology, and has excellent solderability and painting workability (the appearance of insulated wires). It satisfies market demands.

Dear Commissioner of the Patent Office, 1. Display of the case 1982 Patent Application No. 35043 2 Name of the invention Polyurethane electrical insulating paint 3 Person making the amendment Relationship to the case Patent applicant name (445) Hitachi Chemical Co., Ltd. 4 Agent
I corrected it to ``Nylmethane diisocyanate''.

2) Measure the characteristic values of the insulated wire according to JIS C3003 and JIS C3211, as stated in the fourth line of page 13, "The characteristic values of the obtained insulated wire are shown in Table 1." The results are shown in Table 1. ” I am corrected.

that's all

Claims (1)

[Claims] 1, fa) General formula CH2Co (where n is 1 to 5 ((
(b) phenols (C + general formula 〇〇N-■-NCO (wherein R is a divalent aliphatic or aromatic hydrocarbon group) The diisocyanate represented by (al/(b)-s/
2 to 2/8 (molar ratio), and (Cal+(b))
/[C1- A polyurethane electrical insulating paint containing a blocked isocyanate component obtained by reaction at a ratio of about 2.0 (molar ratio) and a polyol component.