SU445311A1 - Process for continuously producing molding materials - Google Patents

Abstract

1. METHOD OF CONTINUOUS PREPARATION OF PRESS-MATER1 {ALOV based on phenol-formaldehyde resins of the novolac and rezol types by polycondensation of a resin from phenol or its homologues with formaldehyde in the form of its aqueous solution in the presence of an appropriate catalyst when heated, mixing the resin and mixture of bulk solids (filler, hardener, dye), homogenous. the plasticization of the resulting press mass, vacuum drying followed by granulation or grinding of the press material obtained. This is distinguished by the fact that, in order to intensify the process, improve the quality of the press material obtained, increase the stability of its properties, reduce raw material losses and reduce harmful emissions to the atmosphere, the polycondensation of phenol and formaldehyde is first carried out at 140-180 ° C under a pressure of 16-25 MPa for 1-6 minutes in the presence of an appropriate catalyst, then onto the resulting aqueous emulsion resin cooled, to 80- 8.4 ° C and distributed in a thin layer, apply a mixture of bulk components at atmospheric pressure, after which they are mixed, homogenized and plasticized for 0.5-1.5 minutes, gradually raising the temperature to 130-160 ° C and pressure up to 20-30 air pressure, vacuum drying at an instantaneous decrease in pressure, heat treatment at 80-120 ° C and granulated masses with a temperature of 85 + 3 ° C. 2. The method according to claim 1, characterized in that, in order to obtain novolac press materials, phenol, formaldehyde and catalyst are taken in a weight ratio of 100: 26-32: 0.4-0.6.4: ^ 4 ^ SLO9

Description

The proposed method relates to the production of thermosetting press materials based on phenol-formaldehyde resins. A known method of continuously obtaining press materials based on phenol-formaldehyde resin by polycondensation of a resin from phenol or its homologues with formaldehyde in the form of its aqueous solution in the presence of an appropriate catalyst during arresting, mixing the resin and a mixture of loose components (body, curing agent and dye) reprocessing and plasticization of the obtained press mass with simultaneous vacuum drying and subsequent granulation or grinding of the obtained press. The purpose of the invention is to intensify the process, improve the quality of the resulting press material, the stability of its properties, improve working conditions, reduce raw material losses and reduce harmful emissions into the atmosphere. For this, the process is carried out at elevated pressure and temperature in hermetically sealed equipment. Source components: phenol (or its homologs), formalin (formaldehyde) and the corresponding catalyst (oxalic acid dihydrate, hydrochloric acid or other inorganic acids, ammonia and metal hydroxides) continuously as a reaction mixture or in separate continuous dosing of each component is fed into the reactor. continuous operation, where the polycondensation reaction occurs at 140-180s and pressure 16-25 air pressure for 1-6 minutes. The resulting products of a high degree of polycondensation (conditional mol. Weight 80 1000) are cooled to 80-84 ° C and removed from the reactor (partial separation of the over-resin water is possible). The resulting water-emulsion resins, having a viscosity of between 250 and 1000 centipoise (depending on temperature and time of polycondensation), continuously enter the pressurized reaction space and are distributed in a thin layer, onto which a mixture of bulk components is continuously applied, containing organic or mineral filler, hardener (hexamethylenetetramine or other amines), dye (mineral or organic), lubricant or plasticizing agent. Continuous mixing, homogenization is carried out for 0.5-1.5 minutes mass and plasticization of the mass in a closed reaction volume with a gradual increase in temperature to 130–160 ° C and pressure to 20–30 atm. In this view, moisture and volatile components do not evaporate. The wet mass, heated to 130160 ° C, is continuously fed to the vacuum zone drying with a temperature of 140160 ° C and a vacuum of 200-600 mm Hg. Due to the instantaneous drop in pressure and high temperatures in the vacuum drying zone, most of the moisture is quickly removed. The dried material enters the heat treatment zone, where the final drying of the material and its heat treatment at a temperature of 80120 С occurs. After that, the material at a temperature of 85 + 3 ° C is molded in the form of bundles with a diameter of 1-4 mm and is continuously removed from the reaction space, cut into pellets and cooled. The finished material contains 35-55% of substances extracted with acetone, and 1.5-2% volatile. B. The case of obtaining a press material. Novolak resin based fishing agents take phenol, formaldehyde and catalyst acid in a weight ratio of 100: 26-32: 0.4-0.6. The resin contains an increased number of orthoses (52-70%) and 1-6% free phenol. In the case of producing resole resin press materials, the starting materials are taken in the ratios customary for this type of resin. Example 1. Phenol, formalin and a solution of oxalic acid dihydrate in formalin are continuously fed to the reactor in a molar ratio of phenol, formaldehyde and dihydrate equal to 1: 1: 0.0033. The resulting mixture is transported continuously in the closed TCW reaction space through three thermal zones, where it is first heated in 1.5 minutes from 20 to 140 ° C, then over the next 2 minutes, the temperature rises to 170 ° C, due to the heat of the exothermic reaction polycondensation and the resulting resin is cooled for 1-1.5 minutes to 80 ° C. In the reactor, the pressure is maintained up to 20 MPa. The cooled resin is continuously withdrawn from the reactor, partly resinous water and a resin containing 20 + 5% residual moisture with a viscosity of 500 ± 50 cps at 80 ° C are partially separated and continuously fed at a rate of 250 g / min (15 kg / h). into a sealed reaction space. A mixture of granular components is continuously applied to a resin distributed in a thin layer at a rate of 240 g / min (14.4 kg / h).

kaolin,

mica 16

Hardener

(hexamethylenetetramine I5,5

Lubricating

substances

(stearate

calcium) 1,5

Dye1.0

For 1 min, continuous mixing, homogenization and plasticization of the mass in a closed reaction volume and gradual increase in pressure to 25 MPa and temperature to ISO-IOO C are carried out. Next, the mass is dried at a temperature of 150 C and a vacuum of 400 mm Hg. within 30-40 s and heat treatment at 90 ° C for 30-20 s. Then, the material at 85 ± 3c is molded into bundles with a diameter of 1-4 mm and is continuously withdrawn from the reaction space, cut into pellets and cooled. The finished material contains 52-55% of substances extracted with acetone, and not more than 2% volatile.

According to physicomechanical indicators, the material can be referred to the group of electrically insulating press materials with increased toughness (n / m b kgf-cm / cm) and tensile strength at static bending (n / m 750 kgf / cm).

Example 2. Proceed as in example 1, using a molar ratio of phenol, formaldehyde and dihydrate, equal to 1: 0.9: 0.0043, and the following composition of bulk components, parts by weight :

Wood flour 46.3

Mineral

additive. 5.2

Hexamethylenetetramine6, 0

Dye1,5

. Grease - oleic acid in the amount of 0.8 wt.h. per 100 weight parts phenol is administered together with phenol and formalin.

Drying is carried out at a vacuum of 300 mm Hg. within 30-40 s The finished material contains 45-48% of substances extracted with acetone, and not more than 2% volatile.

The press material can be classified as a group of general purpose phenoplasts and has an increased cure rate (i.p. and 40 sec on a standard cone cup with preheating with a high frequency current or n / a 70 sec without preheating).

Example Z. The reactor is continuously fed with phenol, formalin and a solution of oxalic acid dihydrate in formalin in a weight ratio of phenol, formaldehyde, and oxalic acid dihydrate equal to 100: 36: 0.45. The mixture is transported in a closed reaction space successively through three temperature zones, where it is first heated

in 1.5 min from 20 to, then in the next 1.5 min, the letting temperature rises to 175 ° C due to the heat of the exothermic polycondensation reaction and the resulting resin cools to 80 ° C. In the reactor, the pressure is maintained at 20-25.

The cooled resin is continuously withdrawn from the reactor and separated from the tar water.

A highly polyno resin, containing 7–10% of methylol groups and having a viscosity of 20,000,300,000 centipoise and a moisture content of 10–15%, is directed into a hermetic reaction space at a rate of 15.015.9 kg / h and distributed in a thin layer that is continuously applied to wood pulp with speed

5 15.7 kg / h (in terms of dry weight L

For 1 min, continuous mixing, homogenization, and plasticization of the mass in a closed reaction volume were carried out with a gradual increase in pressure to 25 atm. temperatures up to 140-1 ° C. Then vacuum drying and heat treatment are carried out at a temperature of 120-80 seconds. During vacuum drying, dyestuff and paste lubricant are introduced into the mass. The time for vacuum drying, heat treatment and cooling to 80 ° C is 30-40 seconds.

The material is formed into bundles with a diameter of 1.5-2.5 mm, cooled to 200–30 ° C and crushed.

The resulting press material of the rezol type can be attributed to the electrically insulating press materials of group 32 and differs from manufactured brands with increased mechanical strength (specific impact viscosity n / m 6 kgf cm / cm; strength at static bend n / m 750 kgf / cm to

Q Example 4. Phenol, formalin and ammonia water solution (20-25%) in a weight ratio of phenol, formaldehyde and anhydrous ammonia equal to 100: 37: 0.375 are fed continuously to the reactor.

five

The mixture is transported in a closed reaction space through three temperature zones where it first heats up in 2 minutes from 20 to 120 ° C, then over the next 2 minutes the temperature rises to 150 seconds due to the heat of polycondensation reaction and the resulting resin is cooled to &; 0 ° C. In the reactor, the pressure is maintained up to 20 MPa.

The cooled resin is continuously withdrawn from the reactor and the resinous water is separated.

A resin containing 12–14% phenol, 10–20% water and having a viscosity of 15,000–20,000 sps (at 20 s, at a rate of 15–18 kg / h is fed into a sealed reaction space and distributed in a thin layer, on which Henpei) iuHO apply a mixture of wood flour with mica in the desired ratio of choenin.

For 1 minute, mixing, huugene formation and plasticization of the mass in a closed reaction volume are carried out with a gradual increase in pressure up to 25 atm and temperature up to 1401 bO. Then vacuum drying and heat treatment are carried out at a temperature of 120-80 s. During vacuum drying, dyestuff and paste lubricant are introduced into the mass.

The time for vacuum drying, heat treatment and cooling to 80 ° C is 30-40 seconds. The material is formed into bundles with a diameter of 1.5-2.5 mm, cooled to 20-ZO S. And emilsch.

The resulting press material, of the rezol type, can be referred to electromolition press materials of the E2 group and differs from the types of high mechanical strength (impact strength n / m 6 kgf cm / cm, tensile strength at static bend n / m 750 kts / ctf

Claims (2)

1. METHOD FOR CONTINUOUS PRODUCTION OF PRESS MATERIALS based on phenol-formaldehyde resins of novolac and rezol types by polycondensation of a resin from phenol or its homologues with formaldehyde in the form of an aqueous solution in the presence of an appropriate catalyst when heated, mixing the resin and a mixture of granular components (filler, hardener, red color ), homogenization and plasticization of the obtained press mass, vacuum drying, followed by granulation or grinding of the obtained press material. characterized in that, in order to intensify the process, improve the quality of the obtained press material, increase the stability of its properties, reduce raw material losses and reduce harmful emissions into the atmosphere, the phenol and formaldehyde are polycondensed at 140-180 ° C under a pressure of 1625 atm for 1 -6 min in the presence of an appropriate catalyst, then a mixture of bulk components is applied at atmospheric pressure to the resulting aqueous emulsion resin, cooled to 8084 ° C and distributed in a thin layer, and then mixed homogenization and plasticization for 0.5-1.5 min, gradually increasing the temperature to 130-160 ° C and pressure to 20-30 ati, vacuum drying with instant pressure reduction, heat treatment at 80-120 ° C and granulating - 5 bath masses with a temperature of 85 + 3 ° C. 2. The method of pop. 1, characterized in that, in order to obtain novolac press materials, phenol, formaldehyde and catalyst acid are taken in a weight ratio of 100: 26-32: 0.4-0.6.