SU974616A1 - Method of obtaining moulding material for printed circuit board substrates - Google Patents

Description

(54) METHOD FOR PREPARING THE PRESS MATERIAL FOR SUBSTRATE PCB SUPPLIES

one

The invention relates to the manufacture of; , electrically insulating press materials intended primarily for the manufacture of printed substrates used in c. radio electronic and telephone equipment.

A known method of manufacturing a press material for substrates of printed circuit boards by impregnating cellulose paper, cotton-to-cloth or glass cloth from resin-curable synthetic fiber, obtained on the basis of phenol, epoxide or unsaturated ether 1.

However, the printed circuit boards of the laminated press material during punching exfoliate around the stamped hole, which leads to an increased water penetration and reduced electrical insulation properties of the substrate of the printed circuit board.

The closest to the proposed technical solution is the method of obtaining 20 Tipecc materials, in which sawdust used as a filler is treated with an aqueous solution of hydrochloric acid followed by impregnation with a hydroxyl organic binder — a mixture of benzyl alcohols 2.

However, the treatment of wood filler with acid leads to a decrease in electrolysis route and 1x properties of the substrate of the printed circuit board during aging.

The purpose of the invention is the improvement of the dielectric properties of the substrates.

This goal is achieved by the fact that according to the method of obtaining a press material for printed circuit board substrates based on chemical treatment of wood filler followed by impregnation with an organic binder solution, chemical treatment of wood filler is carried out in a hydrogen peroxide solution containing a stabilizer and an alkali in the following ratio initial components, wt.%:

Alkali2-6

Stabilizer7-11

Hydrogen peroxide remaining

A water peroxide solution in water is used for treating wood filler, which leads to the oxidation of lignin and oxidative degradation, with the dissolution of a part of hydrophilic hemicelluloses. When exposed to a wood substance, hydrogen peroxide does not leave ions in it, which, by aging, can reduce the electrical insulation performance of the printed circuit board. The alkali in a low concentration acts as a catalyst for the reaction; when impregnated with a hydroxyl organic binder, it participates in the recovery of tar-like products as a catalyst, increasing by the highest percentage of binder in the press material. Example 1. Sawdust in the amount of 0.1 kg {particle size 0, 3.7-19 and humidity 10%) is treated with hot water at a water ratio of 1: 4 for 10 minutes. After treatment with water, a solution of hydrogen peroxide and alkali in the presence of a stabilizer is added to the sawdust with the following content of ingredients, wt%; Hydrogen peroxide83 Alkali6 Stabilizer11 This mixture is added in the amount of 30% by weight of absolutely dry sawdust. Processing time 15 min. After that, the treated sawdust is washed with water and the pH of the pulp is adjusted to 8.0. Then, filtering 1-piece wood pulp is produced to remove excess amount of free water. The resulting wood pulp is impregnated with a 35% strength mixture of bsyl alcohol. The wood press material was dried at 338 K. The pressing time was 1.2 mi per 1 mm thick, 1 product. Example 2. Sawdust in a quantity of 0.1 kg (particle size 0.610 - 3.7-10 m and humidity 10%) is treated with hot water at a water ratio of 1: 4 for 10 minutes. After being treated with water, a solution of hydrogen peroxide and alkali in the presence of a stabilizer is added to the liquids 9 4 with the following content of ingredients, wt.% Hydrogen peroxide 87 Alkali4 Stabilizer9 The mixture indicated is added in an amount of 30% by weight of absolutely dry sawdust. Processing time 15 min. The process is then carried out analogously to example 1. Example 3. Sawdust in an amount of 0.1 kg (particle size 0.6-10 3.7-10 m and humidity 10%) is treated with hot water at a water ratio of 1: 4 for 10 minutes . After treatment with water, a solution of hydrogen peroxide and alkali in the presence of a stabilizer is added to the sawdust with the following content of Ingredients, wt.%: Hydrogen peroxide91 Alkali2 Stabilizer7 This mixture is added in an amount of 30% by weight of absolutely dry opal. The processing time is 15 minutes. The process is then carried out analogously to example 1. The minimum and maximum amounts of the proposed composition are the limit and depend on the type of wood filler. By reducing the amount of hydrogen peroxide in. The composition of the base contains alkali content, which reduces the electrical insulation performance of printed circuit boards. If the percentage composition of hydrogen peroxide is too low, excessive destruction of wood filler is observed, which reduces the physical and mechanical properties of the printed circuit board. In tab. 1 shows the dielectric performance of this material in comparison with the prototype and GOST, in table. 2 - its physical and mechanical characteristics. Table 1

Specific area 2,240 3, resistance, Ohm / m D:) electric 6.96.5 permeability 4.9-10 1-10 5-10 ° 5,57,1

Indicators

Water absorption

Electricity, kV

Specific volume resistance, Ohm / m

Dielectric loss tangent

Dielectric constant

Static bending limit, kgf / cm

Claims (2)

Specific impact viscosity From the press material produced according to the proposed method, substrates for printed circuit boards of telephone sets TA-68M were made. The audit showed that the proposed method allows us to speed up the production of printed circuit boards and improve their quality. The formula of the invention and the method of obtaining a press material for printed circuit board substrates, based on the chemical treatment of wood filler, followed by impregnation with an organic binder solution, characterized by Phenoplast Press material according to the invention (GOST 5689/73. 31-340-02) 0.8 1.2 13.0 21.5 ten 5 10 0.08 0.03 5.6 600 830 4.3 In order to improve the dielectric properties of the substrates, the chemical treatment of wood filler is carried out in a hydrogen peroxide solution containing a stabilizer and an alkali at the following ratio of the initial components, wt.%: Alkali2-6 Stabilizer7- i I Peroxide Hydrogen Remaining Sources of Information , taken into account in examination 1, Patent of the USSR No. 278575, cl. П 05 К 3/00, 1970. 2. USSR author's certificate number 668184, l. H 05 K 1/00, 1977 (prototype).