SU757548A1 - Method of preparing phenolformaldehyde resin - Google Patents

Description

The invention relates to the production of phenolic resins and relates to a method for producing a modified phenol-formaldehyde resin, which can be used as a binder in the manufacture of molding materials, foams, etc.

A method of obtaining phenol-formaldehyde resin, which consists in the co-condensation of the bottoms, phenolic compounds and formaldehyde in an acidic medium at 70-160 ° C for 14 hours. The resulting product is washed with hot water and dried. The finished resin has good static bending strength, high cracking resistance, is thermostable and is intended for the manufacture of adhesives, laminated plastics, etc. [Ts.

This method differs in the duration of the condensation process (12—

14 h), the complexity of the technology (the presence of an additional stage of flushing the condensation product with hot water) ...

Closest to the proposed method is a method of obtaining a phenol-formaldehyde resin novolac type, which consists in the possibility of is-30

2

use of phenolic resin (waste production of phenol and acetone) through isopropyl benzene hydroperoxide. Phenol-formaldehyde resin is obtained by condensation of the bottoms (phenolic resin), phenol and formaldehyde in the presence of hydrochloric acid at 98-102 ° C for 2-3 hours, followed by drying of the condensation product.

In order to increase the rate of curing of the resin, an additional amount of phenol is introduced at the loading stage to a total content of 10–30 wt.% In the phenolic mixture [2].

VAT residue used as a modifier, has the following composition, wt.%:

Phenol 2-, 6 Cumylphenol 30-50 Acetophenone dime- tilphenylcarbinol and o (-methylstyrene 3-15 Dimers with / -methyl styrene 38-57 The disadvantage of this method

is that as a result of it

implementation of the obtained resin, which has a low rate of

, 'curing (gelation time

resin with hexamine 3-4 times higher than the standard resin SF-010, and is 112-417). The use of a resin with such a low cure rate as a binder, for example in press powders, adversely affects the quality of the press materials based on it. Only a partial replacement of the SF-010 resin is possible in the recipe of press powder in an amount up to 25% without a significant change in the physicomechanical and dielectric parameters. Another disadvantage is the duration of the polycondensation stage.

The curing rate of the resin is the most important indicator of the technological properties of press powders, obtained on its basis, causing the performance of equipment at the processing stage. It is known that press powders, in which oligomers serve as a binder, obtained by polycondensation of a mixture of phenols and its homologues with formaldehyde, do not differ in physical and mechanical parameters from press powders based on pure phenol-formaldehyde resins, but are inferior to them in curing speed. ·

The purpose of the invention is the acceleration of the process of polycondensation, increasing the speed of curing of the resin and water-resistance. bones of materials based on it.

This goal is achieved by the fact that in the method, including the condensation of the bottoms of phenol-acetone production, phenol and formaldehyde, 100 weight.h. bottoms phenolacetone production pre-treated 2nd weight.h. sulfuric acid at-110-150 ° C and then condense with 10-90 weight.h. phenol and from 18—

28 weight.h. formaldehyde at boiling point.

Use of the polycondensation reaction bottoms with increased content ¹ nym reactive components reduces condensation step almost doubled and obtain a resin with a high curing speed and a low content of volatiles. '

Press material type 03-010-02 on the basis of the resin obtained by the proposed method has a high curing rate, low water absorption and improved mechanical properties.

Chemical treatment of bottoms phenolacetone production carried out as follows.

Per 100 weight parts bottoms containing 25-30% of free phenol (if necessary, phenol is introduced, better until the molar ratio of phenol: cC-methylstyrene dimer is 2: 1), take 2-10 parts by weight. sulfuric acid (depending on the alkalinity of the system, the pH should be 1.0 f 0.2) and

"(57548 4

the resulting mixture is heated for 0.5-4.0 hours at 110-150 ° C until the OZ-1 reaches a product viscosity of 50-100 s (or 5001,000 centipoise). In this case, the process of depolymerization of the dimer of cC-methylstyrene to cC-methylstyrene and the alkylation of phenol with it to form cumylphenol take place. Dimethylphenolcarbinol alkylates phenol also before the formation of cumylphenol.

Caustic soda binds sulfuric kis .. lotoy to sodium sulfate, which upon ^cooling to room temperature, precipitates and is separated.

Acetophenol, cyclic dimer about methylstyrene and resinous products practically do not undergo changes. 5.

Example. Implementation of chemical treatment of bottom residue.

VAT residue phenol-acetone production, having the composition I (%), 20 is subjected to chemical treatment in the presence of 7.0 weight.h. sulfuric acid at 120-139 ° C for _2 h, while getting a new composition And containing,%:

25

I st

Phenol Cumylphenol 25.3 20.7 14.7 49.36 thirty Acetophenone Dimethylphenyl 12.5 12.3 Carbinol Cyclic dimer g / - 1.85 0 35 methylstyrene Linear dimer In - me- 5.07 9.34 tilstirol Tarry 18.75 0 40 products 13.93 14.3 T a b i Yes 1

Baseline Components - Content, parts Example one 2 3 Sulfuric acid treated bottoms ten 50 90 Formaldehyde 100% 28 22 • 18 Phenol 100% 90 50 ten

Then the temperature of the reaction mixture

s lift gradually to 96-98 C and

maintained at this temperature in

| for 55-70 minutes to the ratio

five

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6

refraction 1.58-1.60, distilled overtime water.

In tab. 2 shows the physico-mechanical properties of the press material based on the resin obtained by the proposed method (example 1) in comparison with the similar properties of the press material based on the resin of the prototype (example 2) and press material brand 03-010-02 (example 3).

table 2

Name indicators Way proposed famous famous example 1 example 2 example 3 based based 03-010-02 resin, resin, Guest software ps received by 568r-73 the proposed method the prototype Colour The black The black The black g Density, g / cm 1.35-1.38 1.36-1.39 No more 1.4 Bulk density, g / cm 0,55—0,58 0,53—0,57 No less Impact strength, kgf * 0.50 * cm / cm ² breaking stress 6.21-7.09 5.3-5.9 Not less than 6.0 with bending, kgf / cm ¹ 805-900 630-700 No less 700 Flowability, mm 145-170 150-170 110-190

Heat resistance according to Martens, ° С

Shrinkage,%

Water absorption, mg

144-168

0.59-0.65

34-40

148-169

0.57-0.72

54-81

Not less than 130

0.4-0.8

Not more than 55 .___________

The use of the proposed method for producing a modified Novolac phenol-formaldehyde resin accelerates the condensation process by 2-2.5 times, increasing the curing rate of the resin and press powder based on it) increasing the water resistance of the press material based on the resin, expanding the range and production of phenolic plastics to meet needs of the national economy.

Approximate annual economic effect per 1 ton of resin will be 174.8 rubles.

Claims (1)

Claim A method of obtaining a phenol-formaldehyde resin, including condensation of the bottoms of phenol-acetone production, phenol and formaldehyde and subsequent drying of the resin, characterized in that, in order to accelerate the polycondensation process, increase the curing speed of the resin and the water resistance of the material based on it, 100 parts by weight VAT residue phenolacetone production pre-treated 2-10 weight.h. sulfuric acid at 110-150 ° C and then condense with 10-90 weight.h. phenol and 18-28 weight.h. formaldehyde at boiling point.