DE1061070B - Process for the production of aqueous phenol-urea-formaldehyde resin solutions - Google Patents

Description

It is known to produce mixed resins from phenol and urea by reacting with formaldehyde. It is also known to mix phenolic resins and urea resins with one another. Find these mixed resins but so far it has been used practically exclusively in neutral or acidic media. Mostly they are for Lacldiarze mainly required in organic solvents.

It was previously unknown to use phenol and / or cresol in an alkaline medium with urea or thiourea or mixtures of both and formaldehyde in the presence of plasticizing agents, such as. B. butanol ₁ to react and to use these synthetic resin solutions for the impregnation of papers or paper webs, which then, after drying and, if necessary, post-condensation under pressure and heat on flat substrates, such as fiberboard and plywood, with the help of press plates with smooth or polished surface or as. Find intermediate layers for laminates use. The films hardened on the surfaces after pressing are characterized by great mechanical hardness, insensitivity to cold and hot water and low brittleness. The disadvantage of strong darkening, which exists with synthetic resins made of phenol and / or cresol that has been condensed with formaldehyde in an alkaline medium, is much less apparent here. The annoying blooming of soda, which also occurs with alkaline condensed pure phenolic or cresol resins, does not occur here.

To prepare the aqueous phenol-urea (thiourea) -formaldehyde resin solutions according to the invention, monohydric or polyhydric phenols and / or cresols with urea and / or thiourea with the addition of butanol with 30 to 37 percent by weight formaldehyde solution, optionally with the addition of paraformaldehyde condensed with caustic soda. The molar ratio of phenol and / or cresol to urea and / or thiourea is 3: 0.5 to 3, the molar ratio of sodium hydroxide to phenol and / or cresol and urea and / or thiourea 0.05 to 0.2: 1, the Molar ratio of phenol and / or cresol and urea and / or thiourea to formaldehyde and optionally parafbrmaldehyde at least 1: 2 to 3, butanol being present in an amount such that the finished synthetic resin solution contains 1 to 10 percent by weight thereof.

It is already known to use mixtures of phenols and aminoplast-forming substances after only a short period of time alkaline condensation mainly in the acidic medium to condense to the end. -At. this Procedure also far outweighs the. Amino

Method of manufacture
of aqueous phenol-urea-formaldehyde resin solutions

Applicant:
Th. Goldschmidt AG,
Essen, Heilermannstr. 15th

Dr. Ulrich Holtschmidt ₁ Essen-Heisingen,
and Dr. Karl Schmidt, Hamburg,
have been named as inventors

plastic part, so that it is a phenol-modified urea resin, which also causes the course of condensation is made understandable .. In another process, either a urea resin is used first condensed, in which small amounts of phenolic bodies are subsequently condensed, or a phenol is added to the urea-formaldehyde starting mixture and then together condensed under acidic conditions, or a urea resin and a phenolic resin are heated together. The three from this Process resulting products are also phenol-modified aminoplast resins.

All these and similarly manufactured products have completely different properties than those after products obtained in the claimed process. These have all the advantages of pure phenolic resins, whereby various disadvantages, namely brittleness, strong darkening and blooming of soda due to the Additives and the type of condensation are omitted. You still have the advantage of being in a single stage Condensation 'can be produced.

example 1

94 parts by weight (1 mol) of phenol, 108 parts by weight (1 mol) of cresol DAB VI, 60 parts by weight (1 mol) of urea, 75 parts by weight (0.85 mol) of sodium hydroxide solution (45%), 200 parts by weight (2.5 mol) of 37% by weight Formaldehyde solution and 45 parts by weight (0.64 mol) of n-butanol are slowly heated to 50 ° C. with stirring. While slowly increasing the temperature to 85 ° C., a further 450 parts by weight (5.6 mol) of formaldehyde solution are allowed to flow in continuously. Fjl is stirred until. a cooled sample has a viscosity of. 12th up to 15 run-out seconds in.

909 560/435

Claims (1)

DIN cup at 20 ° C. - Once this viscosity has been reached, it is quickly cooled. The resin solution is used to impregnate absorbent soda kraft papers. After drying the soaked Paper you get a synthetic resin film, which is excellent for the surface finishing of plywood and Fiberboard is suitable. The hardened synthetic resin layers show great mechanical hardness. The discoloration is essential less than with pure phenolic or cresol resins; the annoying gradual blooming of soda, which is alkaline condensed phenolic resins otherwise occurs, is not to be noticed here. The surface is weatherproof and boil-proof. " Such a film can also be used with advantage for the middle layer of laminates. Opposite to The previously used neutral phenolic resins from alcoholic solution are a cheaper product. The pressing temperature when processing the Surface film according to the invention is also 20 ° C lower. Example 2 282 parts by weight (3 moles) of phenol, 90 ^{parts by weight (1.5 moles) of urea, 65 parts by weight (0.73 moles) of sodium hydroxide solution (45 0} inches), 50 parts by weight (0.7 moles) of n-butanol, 90 parts by weight (3 Mol) paraformaldehyde and 160 parts by weight (2 mol) of 37 weight percent formaldehyde solution are heated to 50 ° C. with stirring. When the temperature is increased to 85 ° C., a further 400 parts by weight (5 mol) of formaldehyde solution are added. The reaction is terminated by cooling when a sample has a viscosity in the DIN cup of 12 to 15 run-out seconds at 20 °. As described in Example 1, the resin is used to impregnate Kraft papers. If the viscosity is driven up to a value of 50 to 70 ¹ leakage seconds in the DIN cup, it is outstandingly suitable for coating papers pre-soaked with a resin according to Example 1, for example. It is also possible to coat veneers or other flat substrates with it and, after drying and, if necessary, re- condensation to harden under pressure against a hot press plate. Example 3 ^: 184 parts by weight (1.78 mol) of a mixture of 60% cresol and 40% phenol, 15.2 parts by weight (0.2 mol) thiourea, 12 parts by weight (0.3 mol) sodium hydroxide and 12 parts by weight (0 , 16 mol) n-butanol are heated to 50 ° C, whereupon with temperature increase to 85 ° C 400 ^! Parts by weight (4 mol) of formaldehyde solution (30 ^fl / oig) are added. It is condensed up to a viscosity of 20 'run-out seconds (DIN cup 20' ° C) and terminated by cooling. The resin is also used to impregnate Kraft papers that are used for surface finishing and shows the advantages described. Claim. Process for the production of aqueous phenol urea (thiourea) formaldehyde resin solutions, characterized in that mono- or polyhydric phenols and / or cresols with urea and / or thiourea with the addition of butanol with 30 to 37% formaldehyde solution, optionally with the addition of paraformaldehyde are condensed with sodium hydroxide in such a way that the molar ratio of phenol · and / or cresol to urea and / or thiourea 3: 0.5 to 3, the Molar ratio of sodium hydroxide to phenol and / or cresol and urea and / or thiourea 0.05 to 0.2: 1, the molar ratio of phenol and / or cresol and urea and / or Thiourea to formaldehyde and possibly paraformaldehyde is at least 1: 2 to 3, butanol being present in an amount such that the finished resin solution is 1 to 10 percent by weight of which contains. Considered publications:
German Patent Nos. 693 098, 865 974;
Swiss patent specification no. 181 453;
U.S. Patent No. 2,483,854. © 909 560/435 6.59