DE561157C - Process for the preparation of resinous condensation products from aromatic amines and formaldehyde - Google Patents

Description

Process for the production of resinous condensation products aromatic amines and formaldehyde The process protected by patent 559 324 leads directly to the production of compacts from aromatic amines and formaldehyde to infusible products.

It has now been found that it is possible to use this manufacturing process in to disassemble two stages, with fusible plastics obtained in the first stage which are converted into infusible plastics in the second stage.

The measure leading to fusible condensation products exists in that initially i mole of an aromatic amine, preferably aniline, with at most i mole of formaldehyde or the equivalent of a formaldehyde-releasing agent in the presence an acid, the amount of which is expediently not significantly less than 1/4 equivalent (based on on the aromatic amine), in the cold or at increased, in all cases but below 100 ° lying temperature, is condensed. The so obtained Condensation products are fusible and solidify when the melt is allowed to cool to brittle, rosin-like, clear or cloudy resins. These fusible Resins can be retrospectively by heating with curing agents, such as. B. aldehydes or aldehyde-releasing agents, such as paraformaldehyde, hexamethylene tetramine or curable aldehyde condensation products, such as. B. Phenolaldehyde condensation products, Urea or thioureaaldehyde condensation products or mixed urea-thiourea condensation products, Aminaldehyde condensation products according to patent 559 324 or mixtures of such condensation products etc., expediently under pressure, converted into the infusible products. the Curing can be done with the resin alone or with mixtures of the same with fillers, Dyes, emollients, etc. are made. The resin can also applied to fabric, paper or other surfaces and in the presence of hardeners of the type mentioned above are hardened by heating, expediently under pressure.

The products thus obtained are for a wide variety of branches of the Plastics industry usable, so z. B. as insulating materials, to the Manufacture of everyday objects and art objects of all kinds as construction material For machine parts and the like that are subject to relatively high mechanical stress have to endure such. B. gears, components of textile machines, such as coils, Weaver birds, etc., also as sealing material, as a substitute for wood in furniture or Construction industry etc.

It has already been suggested, infusible, resinous condensation products from aniline and formaldehyde by first adding aniline and formaldehyde to about 150 ° under partial vacuum until volatile constituents are removed are heated, followed by further heating the meltable resin thus obtained preferably at temperatures above 170 ° under pressure into insoluble, infusible Form is transferred. The initial reaction can be carried out according to the above procedure, if desired by adding catalysts, e.g. B. acids, bases, salts, hardening by addition can be accelerated by curing agents. In contrast, the production of the meltable resin according to the present invention always at temperatures below 100 °, as a rule without any external heat supply at all. On the other hand is always worked in the presence of acid, and not only with catalytic amounts. The acid is removed after the reaction has taken place, causing the fusible resin to precipitate. For the conversion of the fusible resin into the infusible state, the Use of aldehydic hardeners is essential. So it is here not just a measure to accelerate hardening. According to the different Manufacturing processes, the known resins are also different in their properties from those different according to the present invention. The former are self-curing, neutral and insoluble in acids, the latter cannot be hardened simply by heating, are soluble in acids and thus represent high molecular weight bases. Example 1 93 Parts of aniline (1 mol) are mixed with 100 parts of 36% hydrochloric acid (1 mol) in zoo parts Dissolved in water. At a temperature of 25 °, 75 parts of a 40 ° formaldehyde solution are used added (1 mole). The temperature of the solution rises to 35 to 40 °, its color goes into a deep red. After about an hour, the condensation product formed is with a solution of q.o parts of sodium hydroxide in 100 parts of water as thicker Mash is precipitated, which is filtered off, washed free of electrolytes and dried. That The yellowish powder obtained turns into a light melt at i2o °, which turn into a brown insoluble in the common solvents in the cold Resin solidifies.

Mixed with a few percent paraformaldehyde, it can be mixed with or without the addition of fillers, dyes, softeners etc. by heating transfer under pressure into the synthetic materials described above.

Example 2 93 parts of aniline (1 mol) are mixed with 25 parts of 36% Hydrochloric acid (0.25 mol) emulsified in zoo parts of water. For this purpose, 75 parts of a q.o ° / qigen formaldehyde solution (1 mol) added. The result is a deep red, something more viscous solution than in example i.

The work-up is carried out according to Example i. The resin obtained melts at i8o to 200 ° and is hardened according to example i.

Example 3 i Part of the meltable resin prepared according to Example i is mixed with i part of a rapidly curing phenol-formaldehyde condensation product and 2 parts wood flour. The mixture shows, when compressed at about 150 °, a very good one Flowability and provides fittings of great homogeneity and strength.

Example q.

93 parts of aniline (1 mol) are mixed with 100 parts of concentrated hydrochloric acid and 112 parts of a 37.5 ° Joigen formaldehyde solution condensed. The mix will neutralized with sodium hydroxide solution after condensation is complete. The precipitated resin is washed electrolyte-free, crushed, dried and mixed with 1q.o parts of wood flour mixed. 70 parts of this molding powder are mixed with 30 parts of one according to the example i produced fusible resin.

The mixture shows, when compressed at i 50 ', a very good flow and delivers extremely homogeneous pressed pieces.

Example 5 e ioo parts of a manufactured according to Example i fusible aniline formaldehyde condensation product are ground together with 2o parts of furfural. By pressing the powder obtained at elevated temperature, deep black, infusible molded pieces of good mechanical and electrical strength are obtained.

Example 6 Instead of the aniline in Example i, an equivalent amount of m-toluidine is condensed in the manner described there with the equivalent amount of formaldehyde. The dried fusible condensation product is ground with 309, its weight of furfural and then subjected to pressing at an elevated temperature. In this way, deep black, infusible shaped pieces of versatile technical applicability are obtained. Example 7 10 8 parts of m-phenylenediamine (1 mol) are dissolved in 100 parts of concentrated hydrochloric acid (1 mol) and 500 parts of water. 80 parts of formaldehyde 37.8% -1 mol are added to this solution. After the condensation is complete, the reaction mixture is poured into dilute sodium hydroxide solution, whereby the condensation product is precipitated as a brown precipitate. The same is washed free of electrolytes and dried. It represents a meltable, brown mass. 50 parts of this product are ground together with 30 parts of wood flour and 16 parts of furfural and then pressed in a heatable press. The well-flowing mixture provides homogeneous, brown, infusible fittings. Example 8 50 parts of the fusible condensation product described in Example 6 are mixed with 5 parts of paraformaldehyde and pressed at elevated temperature. Brown moldings of good mechanical strength are obtained.

Claims (1)

PATENT CLAIM: Process for the production of resinous condensation products from aromatic amines and formaldehyde, characterized in that one first i mole of an aromatic amine with a maximum of i mole of formaldehyde or the equivalent of a formaldehyde-releasing agent in the presence of an acid, the amount of which is appropriate is not significantly below equivalent (based on the aromatic amine) Temperatures below 100 ° condensed and the resulting meltable resin after removal of the acid, on its own or in a mixture with fillers, dyes, Plasticizers, etc. by treatment with hardeners in the infusible Transferred state.