SU1684302A1 - Compound for protection of printed circuit boards - Google Patents

Abstract

The invention relates to the production of coatings for moisture protection and electrical insulation of printed circuit boards with installation in electronic equipment. The invention makes it possible to increase the viability of the composition up to 4-8 hours by using the composition in composition, wt.h.: epoxy resin Dianova 100; the hardener is hydrofluoric acid in the form of a 40% aqueous solution of 1.0-1.5, 1.5-3.0 wt.h. para-aminobenzoic acid as a gelation inhibitor, 20.0-30.0 wt.h. isopropyl alcohol and 65.0-85.0 wt.h. an organic solvent selected from the group comprising acetone, toluene, ethyl acetate. 3 tab. Ј Epoxy resins of the following types are used in the compositions: ED-20, ED-16, and E-40. The composition is prepared as follows. A portion of the epoxy resin is dissolved in an organic solvent (toluene, ethyl acetate or acetone). To the resulting solution, a pre-prepared solution of n-aminobenzoic acid and hydrofluoric acid in isopropyl alcohol is added and mixed thoroughly. O 00 00 O N3

Description

Another option is to prepare the composition, which includes the sequential dissolution of the epoxy resin and n-aminobenzoic acid in an organic solvent, followed by adding to the resulting solution a solution of hydrofluoric acid in isopropyl alcohol.

To obtain coatings, the finished composition is applied to the sample (substrate) by any known method (dipping, pouring, spraying or brushing), the samples are kept in air for 15-20 minutes to remove the bulk of volatile solvents, then cured in a heating cabinet at 60 ° C. Examples illustrating the invention are presented in table 1.

Table 2 presents data on the properties of the compositions.

Table 3 presents data on the properties of coatings.

0

five

0

five

Claims (1)

DETAILED DESCRIPTION OF THE INVENTION Composition for the protection of printed circuit boards, comprising an epoxy resin Dianova, a hardener - hydrofluoric acid in the form of a 40% aqueous solution and a gelation inhibitor, characterized in that, in order to increase its viability, it contains as a gelation inhibitor para-em - nobenzoic acid and additionally isopropyl alcohol and an organic solvent selected from the group including toluene, acetone and ethyl acetate in the following ratio of components, parts by weight: Epoxy Dianova s mola100; Hydrofluoric acid (40% aqueous solution) 1.0-1.5; para-aminobenzoic acid1, 5-3.0 Isopropyl alcohol20-30 Specified organic solvent65-85 Table 1 table 2  The viability of a known composition is 9-415 seconds. Indicators Color and appearance of the coating Thickness of single layer coating um Cure time at 60 ° C. min The hardness of the coating on the device ME-3, standard units, not less Coating strength at impact device U-2M, cm on fiberglass on steel Adgezi, points on fiberglass on steel Electric strength, kV / mm Specific volume resistance, Ohm cm in the initial state After exposure at 40 ° C and a relative humidity of 98% for 96 hours The tangent of dielectric loss angle at a frequency of 103 Hz. Dielectric constant at a frequency of 103 Hz. After curing, a glossy transparent film is formed with a yellowish tinge. 40-50 30 0.8 50 15 1 4 60 1 10 15 10 10 0.02 4.2 12 Micrometer The content of the gel fraction is not less than 90% GOST 5233-67 GOST 4 / 65-73 GOST 15140-78 GOST 6433.3-71 GOST 22372-77 GOST 22372-77 Continuation of that b l 2 Table 3 Norm Test methods Micrometer The content of the gel fraction is not less than 90% GOST 5233-67 GOST 4 / 65-73 GOST 15140-78 GOST 6433.3-71 1 10 15 GOST 22372-77 GOST 22372-77