CH228445A - Process for the production of thermal insulation compounds. - Google Patents

Description

  

  Process for the production of thermal insulation compounds. It is known to produce porous, more or less rigid thermal insulation means by converting a wide variety of materials into foamy solutions (masses) by adding foam-forming substances or from foam made from them and subsequently bringing them to hardening in some way.



  Suitable substances for this have been proposed and used: cellulose solutions (as copper-ammonia or xanthate solution), casein, albumin or their derivatives, etc., and also urea-formaldehyde resins or thiourea-aldehyde resins, etc. .



  An essential feature of all these processes is the addition of a foam-forming or foamy substance in order to be able to force a foam structure on the medium in question until it hardens. This additive, which acts as a foreign body in the finished porous mass, mostly affects the quality of the material by making it more brittle or less resistant to water.



  It has now been found that these disadvantages are avoided and that much tougher, more resilient compositions are obtained, and that the addition of foaming or foamy substances is made unnecessary if the curable resins are replaced with the previously used solutions Urea and / or thiourea or their derivatives with aldehydes, suitable mixed condensation products of urea and phenols-with aldehydes are used.



  The subject of the present patent is a process for the production of iWärme- insulating masses by foaming of aqueous synthetic resin solutions and hardening of the foam, which is characterized in that aqueous solutions of mixed condensates of urea and phenols with aldehydes by vigorous agitation, without the addition of a foaming agent , foams and hardens the foam. By using the 3-table condensate it is achieved that if there is vigorous movement, sufficient foaming occurs without the addition of a foaming agent.

    The mixed condensation products can easily be converted into foamy masses by stirring or beating or by spraying using a suitable apparatus.



  The hardening takes place in the usual way, preferably by means of acidic media, d. H. by acids or acidic salts that can be incorporated into the mixed condensate during or after the foaming. A small excess of aldehyde or the addition of aldehyde-releasing substances, for example hexa.methylenetetramine, is useful for subsequent transfer of the phenoplast content to the insoluble C = stage.



  The porous Isoliermas sen produced in this way are tougher and more resistant than the previously known similar products. The size and number of pores and thus their density can be varied to a large extent by regulating the air supply.



  It has also been found that the addition of water-soluble fatty acids, for example formic acid or its water-soluble homologues, or their salts during the condensation process can significantly increase the toughness of the product.



  Likewise, a small amount of zinc chloride or its solution added before or during foaming improves the product and, above all, increases the resistance of the foam, which significantly reduces the amount of polymerization catalysts required, which in turn improves the quality of the material improved.



  <I> Example: </I> Urea and formaldehyde as 40% formalin, in a molar ratio of 1: 2.3 to 1: 2.5, are condensed at certain pH values close to 7 and after 15 hours with "/ 2a mol of cresol with a high m.-cresol content and the corresponding amount of aldehyde are added and the whole is boiled for a further 5 hours on the reflux condenser.

   The addition of aldehyde with the cresol can be dispensed with if there is still enough free aldehyde in the urea condensate.



  The finished mixed condensate is diluted with one to two times the amount of water and placed on top. For example, with a foam syringe, poured in any shape using a pouring pipe.



  An additional device on the pump supplies the necessary curing or polymerization catalyst, for example an acid or an acidic salt, during the foaming process. By regulating the number of revolutions or various actuation of the air and liquid valves, the bubble size and thus the volume weight of the product can be largely varied.



  The further treatment of the masses, which can already be molded after a few hours, in particular drying, etc., takes place in the manner customary for urea formaldehyde, i.e. resin masses, in order to avoid shrinkage cracks.

 

Claims (1)

PATENT CLAIM: Process for the production of thermal insulation compounds by foaming aqueous synthetic resin solutions and hardening the foam, characterized in that aqueous solutions of mixed condensates of urea and phenols with aldehydes by vigorous agitation. without adding a foaming agent, causes foaming and hardens the foam. SUB-CLAIMS 1. The method according to claim, characterized in that a zinc salt is added to the mixed condensate before foaming. 2. The method according to claim, characterized in that a zinc salt is added to the mixed condensate during the overshipping. 3. Process according to claim, characterized in that mixed condensates are used which have been produced by condensation of urea and phenols with aldehydes in the presence of water-soluble fatty acids or their salts. 4. The method according to claim, characterized by the fact that excess aldehyde or aldehyde-releasing substances are added to the mixed condensate.