SU753878A1 - Electroinsulating varnish - Google Patents

Description

This invention relates to electrically insulating polyvinyl formal lacquers for enameling wires with a diameter of predominantly 0.02-0.3 mm on high-speed enamel equipment. A polyvinyl formal lacquer containing polyvinyl formal resin, resole resin based on phenolic compounds and formaldehyde, and melamine formaldehyde resin is known. Such a lacquer in which polyvinylformal resin with a viscosity of 5OO-6OO cP {.-O is used for enameling wires at relatively high speeds and forms insulation with good electrical strength. The disadvantages of this lacquer are the relatively low oil resistance and resistance to heat aging, as well as the impossibility of achieving higher enamelling rates. Also known is polyvinyl formal lacquer 23, the contents of polyvinyl formal resin, resole thermosetting resin based on phenolic compounds and formaldehyde resin, melamine formaldehyde resin, blocked triisocyanate and organic solvent. The lacquer contains polyvinylformal resins with molecular masses 24OOO-4000O and 16000-200OO and a content of 5% O6 hydroxyl groups, 5 wt.%. This lacquer, however, cannot be used to enamel thin wires on modern high-speed enamel equipment. The purpose of the invention is to increase the oil, durability | resistance to heat aging and an increase in the enamelling rate. To achieve this goal, according to the invention, the lacquer as a polyvinylformal resin comprises a resin with a molecular weight of 15OO-4OOO and a hydroxyl content of 3.5-6.2 wt.% In the following ratio of components, parts by weight: Polyvinylformal resin 10O. Reole thermosetting resin7,7-45,1 Melamine-formaldehyde resin 4,0-9,3 Blocked triiso-cyanate 50,5-58,7 7538 5 84 Organic solvent 6OO-1100 The specific content of the components depends on the type of solvent. 1 shows examples of the formulations of the proposed varnish. Table 1

Polyvinylformal resin (MO mass. 2OOO-ZOOO,% OH 4.5-5

Xylenol formaldehyde resin (20% solution in dicresol)

Blocked triisocyanate

Melamino-fmaldehyde resin (48% solution in butanol)

Tricresol

Phenol

Solvent naphtha

Polyvinylformal acid (mol. Mass. 2000-3000,% OH 5.6-6.2)

Xylene Formaldehyde Resin (20% solution in Dicresol)

Blocked triisoianos

Melamine formaldehyde resin (48% solution in butanol)

Tricresol

Phenol

Solvent naphtha

Polyvinylformal resin (mol. Masses. 2OOO-3 LLC,% OH 4.5-5.1)

Resol Resin RSF-ZO43 (44% solution in Dicresol)

Blocked triisocyanate

Melamine formaldehyde resins (48% solution in butanol)

Tricresol

Formulation 1

Phenol Solvent-Nafta

Varnish is prepared as follows.

A solvent and a solution of the resole resin are added to the suspension of polyvinylformal resin in a thinner with vigorous stirring and heating to a temperature of no more than 45 ° C and stirring is continued until a homogeneous solution is formed. To the resulting solution is added a solution of melamine formaldehyde resin and pre-ground

Enamelling speed

m / min

Elasticity,

initial, jerk to break

after heat aging

within 24 hours at

temperature, with

Continued table. one

50,438.6

Formulation 4

blocked triisocyanate, the process ends with the formation of a clear solution.

The physicochemical properties of the proposed lacquer and the insulation characteristics of wires with a diameter of 0, O6 mm are shown in Table. 2. For comparison, table. Figure 2 shows the insulation performance of wires based on a known varnish.

Table 2

22 o

150

28O

Endures

Endures

Withstand withstand

155155125 Ф is a chemical-chemical property Number of point damages Electrical strength, V / 0.01 mm153О 161О Break resistance by the method of forcing at, h. Benchability by the method of forcing at 25 ° C, h As can be seen from the table. 2, the proposed lac allows to enamel wires at high speeds, for example, 280 m / min for a wire of diameter O mm (15 m / min for lime varnish), the insulation on the basis of such varnish has a high resistance to light (38 hours at 1 ° C ) and resistance to heat aging (24 hours at 16O С), which is significantly higher than the analogous characteristics of isoL5ShCH1 based on the known varnish. Invention Formulas Electroisol diop varnish comprising polyvinylformal resin, thermoset resole resin, melamine formaldehyde resin, blocked triisocyanate, and organic solvent, distinguished by the fact that, in order to increase oil resistance, increase resistance to heat aging, and increase its resistance to heat aging and to increase it.

PVP-83 lacquer The recipe number of the proposed lacquer ZElZilZIIII O 6 OOI enameling, as a polyvinylformal resin, it includes a resin with a molecular weight of 1500-4000 and a hydroxyl content of 3.5-6.2 wt.% With the following ratio of components, parts by weight:: Polyvinylformal resin 10 Rezolna thermoreactive resin 7,7-45,1 Mela, Formaldehyde resin 4,0-9,3 Blocked triisocyanate 50, 5-58,7 Organic solvent 600-11OO Sources of information. taken into account during the examination 1. Insulation lacquer SIVA PVF / 83, prospectus of the company 5.1, S.M.E., Italy, 1969 2. U.S. Patent No. 34О4197, cl. 260-839, publ. 1968 (prototype).

Claims (1)

Claim An electrical insulating varnish, including polyvinyl formaldehyde resin, thermosetting resin, melamine formaldehyde resin, blocked triisodianate and an organic solvent, characterized in that, in order to increase oil resistance, resistance to heat aging and increase the rate of enameling, it includes a polyvinyl formalde resin with a mass of 1,500 molecular weight resin and it includes -4000 and the content of hydroxyl groups of 3.5-6.2 wt.% In the following ratio of components, wt.h .: Polyvinyl Formal Resin 100 Resole thermoset— live resin 7.7-45.1 ³⁰ Melamine formaldehyde naya resin 4.0-9.3 Blocked triiso cyanate 50.5-58.7 Organic plant ³⁵ thief 600-1100