Powder redispersible in water, process for production thereof and use thereof

Abstract

The present invention relates to an additive for hydraulically binding systems for reduction of blooms in hydraulically bound systems, which is preferably present as a powder redispersible in water and is suitable in particular as additive for addition in dry mortars. The powder redispersible in water consists of at least one organic component and at least one water-soluble organic polymeric protective colloid and also if appropriate further additives, with the organic component containing at least one compound having a cyclic group which is completely or partially saturated and having a melting point of about −20 to 250° C. and also a molecular weight of about 100 to 10 000, and forming a stable dispersion in water with the water-soluble organic polymeric protective colloid, with the weight ratio of the organic component to the water-soluble organic polymeric protective colloid being about 95:5 to 5:95. The invention also relates to a process in which the drying step is omitted. The additive of the invention can be used in hydraulically binding masses, in particular in concrete, gypsum and/or lime and/or cement plasters, repair mortars and/or full heat protection mortars, jointing adhesives and/or tile adhesives, levelling compounds and/or fillers, non-shrink grouting and/or as additive for concrete coatings and for adhesives.

1 . Powder redispersible in water comprising:
 an organic component having at least one compound with a cyclic group, the compound being completely or partially saturated and having a melting point of approximately −20 to 250° C. and a molecular weight of about 100 to 10,000, the organic component further having a terpeneoid, a resin acid, colophony, terpene resin, terpene-phenol resin and/or their derivatives, and   a water-soluble organic polymeric protective colloid,   wherein the organic component and the protective colloid form a stable dispersion in water, the water-soluble organic polymeric protective colloid having a content of monocarboxylic acid and dicarboxylic acid as well as their anhydrides of less than 50 mole %, and not consisting of aromatic sulfonic acid, condensates, and   wherein the weight ratio of the organic component to the water-soluble organic polymeric protective colloid is 95:5 to 5:95, and   wherein the powder reduces efflorescence in hydraulically set systems.   
   
   
       2 . Powder according to  claim 1  wherein the cyclic group of the organic component is a monocyclic, dicyclic, tricyclic, tetracyclic and/or pentacyclic group. 
   
   
       3 . Powder according to  claim 1  wherein the organic component is a natural product. 
   
   
       4 . Powder according to  claim 1  wherein the organic component further comprises at least one compound with at least one carboxyl group, carbonyl group, aldehyde group and/or alcohol group. 
   
   
       5 . Powder according to  claim 1  wherein the organic component further comprises abietic acid, sylvic acid, neoabietic acid, levopinaric acid, pimaric acid, isopimaric acid and/or palustric acid and/or their derivatives. 
   
   
       6 . Powder according to  claim 1  wherein the organic component is not or only slightly soluble in acidic to neutral water. 
   
   
       7 . Powder according to  claim 1  wherein the organic component is partially or completely soluble in dilute caustic soda solution. 
   
   
       8 . Powder according to  claim 1  wherein the water-soluble organic polymeric protective colloid is a synthetic protective colloid in the form of a modified and/or unmodified polyvinyl alcohol with a degree of hydrolysis of 70 to 100 mole % and a Höppler viscosity, as 4% aqueous solution, of 1 to 50 mPas, measured at 20° C. according to DIN 53015, and/or polyvinyl pyrrolidone. 
   
   
       9 . Powder according to  claim 1  wherein the water-soluble organic polymeric protective colloid is a natural and/or synthetically produced biopolymer that can be synthetically modified. 
   
   
       10 . Process for the production of powders redispersible in water according to  claim 1  comprising:
 dispersing the organic component in water,   stabilizing the dispersion with the water-soluble organic polymeric protective colloid, and   drying the aqueous dispersion thereby forming the redispersible powders.   
   
   
       11 . Process according to  claim 10  wherein the solids content of the stabilized dispersion is approximately 10 to 75% by weight and the average particle size of the dispersed particles to approximately 0.05 to 50 μm. 
   
   
       12 . Process according to  claim 10  wherein further liquid and/or water-soluble additives are added before, during or after formation of the dispersion, and further additives in powder form are added during or after drying. 
   
   
       13 . Process according to  claim 10  further comprising mixing the redispersible powder with film-forming dispersion powders redispersible in water, redispersible hydrophobing agents in powder form based on silanes, siloxanes, silicones, fatty acids and/or fatty acid esters and/or polysaccharide ethers. 
   
   
       14 . Process according to  claim 10  wherein the aqueous dispersion is dried jointly with at least one other dispersion based on film-forming polymers and/or silanes, silane esters, siloxanes, silicones, fatty acids and/or fatty acid esters, wherein the dispersions are mixed with each other before drying or sprayed separately and subsequently dried jointly. 
   
   
       15 . Process according to  claim 14  wherein the aqueous dispersion is stabilised by emulsifiers and the at least one other dispersion comprises an excess of water-soluble organic polymeric protective colloid in water, the water-soluble organic polymeric protective colloid having a content of monocarboxylic and dicarboxylic acids and their anhydrides of less than 50 mole % and not consisting of aromatic sulfonic acid condensates. 
   
   
       16 . Powder redispersible in water obtained according to the process according to  claim 15 . 
   
   
       17 . (canceled) 
   
   
       18 . (canceled) 
   
   
       19 . (canceled) 
   
   
       20 . (canceled) 
   
   
       21 . (canceled)