SU64571A1 - The method of obtaining resins and plastics - Google Patents

Description

The alkaline and hydrolytic lignin released is the first of the black liquor soda and sulphate pulp production processes, and the second is used as a waste in the hydrolysis of wood, in the production of plastics both directly and as condensation products with phenol.

Since the discovery of Bühler (germ. Pat. 94467), a series of studies has been devoted to phenol lignin condensation. The work of Kalb and Schiller (Cell. 4.37, 1923) and especially Hilmer (Cell. 6.169, 1925) established the chemical nature of the interaction of phenol with lignin. Wedekind, Brown and Gibbert (J. Am. Them. Soc. 4720, 1933) and later Fuchs (J. Am. Chem. Soc. 58.673, 1936) established the nature of phenol-ligned condensates. In the works of S. N. Ushakov with co-workers (Lesohim. Industrial No. 1939 No. 1, Bulletin of Glavkhimplast 1940 No. 3), as well as I. P. Losev, technical processes for the preparation of phenol-lignin condensates in the presence of an acidic or alkaline catalyst were established. A description of the condensation of alkaline lignin with phenol is given in the work of M. Bertolini (Kunststotfe 1941 No. 2). In p de

American methods of alkaline lignin are introduced into the composition with phenolic resins.

Leaving aside the use of lignin directly as such and in composition with phenol-aldehyde resins, in all other cases the condensation of phenol with lignin is carried out to produce a condensation product, to which Brown and Gibbert are credited with the formula;

Thus, 4 mol. Per one molecule of lignin is bound. phenol.

The condensation product, containing a certain amount of free phenol, is mixed with hexamethylenetetramine, a filler (wood flour, etc.), a lubricating plasticizer, etc. to form pressing plastic masses.

Thus, in all known cases of using insulated lignin to form resins and plastics with phenol, the main process is condensation, carried out in the presence of an acidic or alkaline catalyst (sometimes with the addition of formaldehyde). The condensation operation is long and complex and is associated with strong equipment corrosion due to the volatile organic acids released during condensation.

The inventor has found that the process of producing plastics based on alkaline lignin and phenol can be built on completely different principles. According to the author's observations, alloys of phenol and alkaline lignin, the formation of which is not accompanied by chemical bonding of phenol with lignin, when treated with hexamethylenetetramine (or solid formaldehyde polymers) react when heated to form a final infusible and insoluble product, which in properties corresponds to the final product of the interaction phenololine (condensate) with hexamethylenetetramine. In terms of their structure, however, these products are very different from each other, since there is no direct link between the molecules of lignin and phenol. In this case, the process of the formation of the final product can be considered as a process of co-polycondensation, in which methylene bridges are formed between the reactive points X of the phenolic X

derON x and aromatic

X drains of lignin:

y-CH2- - OH

CHs

L OH

Y / / -7 /

Here, phenol plays the role of a lignin solvent (alkaline) and a homogenizer; in a homogeneous medium, it easily enters into a reaction of copolycondensation with lignin and hexamethylenetetramine. The amount of lignin introduced into the composition of the alloy with phenol can reach 300% or more of phenol.

In addition to phenol, its homologues can also be used (cresols, peat phenols, etc.).

An amount of hexamethylene mine is enough to form a non-meltable and insoluble end product, about 10% by weight of the alloy. To form a press plastic, the alloy of phenol with lignin is ground and mixed with ground hexamethylenetetramine, a filler (wood flour), a lubricant component. The resulting mixture is homogenized, for example, by processing on a hot roll mill, then ground. The resulting powder for the manufacture of products is subjected to hot pressing.

The manufacture of the alloy of phenol with lignin can also occur directly on the rollers. The ratio of alloy and filler can vary widely.

Example. 100 parts of phenol is melted in a reaction boiler, heated to PO-135 °, and 300 parts of ground and dried alkaline lignin are gradually added to the molten mass. After the introduction of lignin, the resulting mixture is heated for 1 hour. After cooling, the mixture is pulverized (100 mesh) and mixed with wood flour (70 mesh), hexamethylenetetramine and calcium stearate. (For example, for 48 parts of the alloy, take 46.2 parts of wood flour, 4.8 parts of hexamine, 1 part of calcium stearate). The resulting mixture was worked up on a hot roll at a temperature of about 130 ° for two minutes and the resulting sheets, after cooling, were ground into powder (30 mesh).

The powder is pressed under the conditions usual for normal phenol-aldehyde compaction powders.

Pressmass properties:

Resistance to impact bending — no less than 4 kg / cm. Resistance to static bending — no less than 500 kg / cm. Water resistance — more than 0.5%. Surface electrical resistance — about 2 Prev of the invention 1. Method for producing resins and plastics based on alkaline lignin and phenol ( or its homologs), - - # 64571 characterized in that the alloy of phenol and alkaline lignin, obtained in the absence of catalysts, is shifted with hexamethylenetetramine (or solid polymers of formaldehyde). 2. A composition according to claim 1, characterized in that the resin is mixed with fillers and other commonly used components.