SU408954A1 - VPTB - Google Patents

Description

one

The invention relates to the field of phenol-formaldehyde resin resol formation, for example, for gluing dry nodules and high water resistant plywood without drying the bonded multi-stage condensation of phenol with formaldehyde in an alkaline environment.

Characteristic features of the phenol-formaldehyde resin used in this area are the curing time, the content of significant amounts of free phenol and formaldehyde.

In order to obtain a water-soluble fast-curing resin with a lower content of free phenol and formaldegnd, the alkalinity of the medium is established by adding 0.4-0.7 mol of alkali per 1 mol of phenol and the nerve stage is carried out with the introduction of 1-1.3 mol of formaldehyde per 1 mol of phenol and those at 50–55 ° С with the next cooling to 20–30 ° С, the second stage is the introduction of 0.4–0.7 mol of formaldehyde per 1 mole of phenol in the temperature range of 35–55 ° С with the next cooling to 25–5 ° C. 30 ° С and the third stage - at the introduction of 0.2-0.4 mol of formaldehyde per 1 mol of phenol and trie ature from 80 ° C to the temperature of the film with obtaining a resin of a given viscosity. The resulting resin contains up to 2.5-3% free phenol and formaldehyde, and its curing time at 150 ° C is 120 sec.

Example 21.5 wt. including alkali dissolved in 108.5 wt. including water and loaded into the reactor. Then at temneture download 100 weight. including phenol and stirred until complete dissolution. At a temperature of 40 ± 2 ° C pour 104 wt. including 37% formalin. The reaction mixture, which was agglomerated by exothermia to 50-55 ° C, was then cooled for 1-3 hours to 20-30 ° C.

The 25 ° C prn is used to introduce a new standard of formalite concentration in an amount of 52 wt. hours, the mixture is iodine heated to 35-40 ° C, and then the Smesp temperature rises to 50-55 ° C due to the exotherm of the reaction. The heated mixture is cooled for 1-2 hours to 25-30 ° C and maintained for 1-2 hours at this temperature.

Next, the mixture is heated to 85-90 ° C, maintained at this temperature for 0.5-1 hours, the mixture is brought to a boil, maintained at this temperature for 10-30 minutes, cooled to 80-85 ° C, the third norm is introduced formalin 26 wt. hours and condensed at 80-90 ° C until the resin has the desired viscosity.

The resulting resin is characterized by the following indicators:

Concentration of dry substances,% 41 ± 2 Content of free phenol,% 0.18

3

The content of free formaldehyde,% 0,18

Alkalinity,% 4.5 - 5.5

Content of brominated substances,% 11 - 15

Content of volatile substances,% Up to 60

Cure time at 150 ° C, s.60

Ud. weight, r / CM-i1,016

Curing temperature, ° С125

Period of storage in months 2 - 3

Viscosity iO Engleru 40 - 60

Water solubilityFull

The resin can be used to glue 1 ply plywood of any thickness without drying

Adhesives |

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PROPOSITION OF I AND ABOUT.

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 Sporb pr / 1ch1L1 reflex phenol-formaldehyde with a molar, for example, for gluing

chipboard nlit and high-rise plywood without sui1ki applied. glue, by multistage condensation of phenol with formaldehyde in an alkaline medium, which is different from the fact that, in order to obtain a water-soluble fast-curing resin with a lower content of free phenol and formaldehyde, it is established that the medium is alkaline by adding 0.4-0.7 mol

At about 1 mol of phenol c, the first stage is carried out by introducing 1-1.3 mol of formaldehyde per 1 mol of phenol and a temperature of 50-55 ° C, followed by cooling to 20-30 ° C, the second stage is introduced

0.4-0.7 mol of formaldehyde per 1 mol of fairy 10la at a temperature of 35-55 ° C, followed by cooling to 25-30 ° C and the third stage, with the introduction of 0.2-0.4 mol of formaldehyde per 1 mol of phenol iri temperature from 80 ° C to

topic) boiling to obtain a resin of a given viscosity.