Process and additive to improve adhesion of building compositions to substrates

Abstract

The present invention relates to the use of an additive as well as a process to improve the adhesion of a mortar to a building substrate, wherein the mortar is mixed with said additive and is applied to a building substrate selected from the group of polystyrene-containing substrates, polyolefin-containing substrates or polyvinyl chloride-containing substrates, the additive containing (i) a plasticizer that is liquid at 50° C. or lower, has a boiling point of 100° C. or higher, and that has a solubility parameter δ 25° C. between 22.5 MPa 1/2 and MPa 1/2 ; (ii) optionally, a filler that has a BET surface area of at least 40 m 2 /g; (iii) optionally, a biopolymer, (iv) optionally, a protective colloid; and (v) optionally, a water-insoluble film-forming (co)polymer based on ethylenically unsaturated monomers. The invention also covers an additive and a kit of parts suitable for use in the above process.

1 . An additive for addition to a mortar, the additive containing
 (i) a plasticizer that is liquid at 50° C. or lower, has a boiling point of 100° C. or higher, is capable of dissolving 1 wt % of the building substrate, and that has a solubility parameter δ at 25° C. between 22.5 MPa 1/2  and 11 MPa 1/2 , the plasticizer being selected from the group of esters, ketones, aldehydes, carbonates, aromatic compounds, heteroaromatic compounds, heterocyclic compounds, halogenated hydrocarbons, cyclic unsaturated compounds, terpenes, sulfates, and sulfoxides;   (ii) optionally, a filler that has a BET surface area of at least 40 m 2 /g;   (iii) optionally, a biopolymer such as a cellulose ether;   (iv) optionally, a stabilizer such as a protective colloid; and   (v) optionally, a water-insoluble film-forming (co)polymer based on ethylenically unsaturated monomers.   
     
     
         2 . The additive according to  claim 1 , wherein the additive is
 a) in the form of a powder obtained by adsorbing the plasticizer (i) on a component selected from a mortar component and the components (ii), (iii), (iv) or (v), said component being in powder form; or   b) in the form of a liquid dispersion or powder obtained by mixing the components (iii) and/or (iv) in water to form a pasty, swollen or dissolved mixture, followed by admixing the plasticizer (i) and optionally drying the obtained admixture to form a powder.   
     
     
         3 . The additive according to  claim 1 , wherein the additive contains the plasticizer (i) and at least one of the components (ii), (iii), (iv) or (v). 
     
     
         4 . A process to improve the adhesion of a mortar to a building substrate, wherein the mortar is mixed at least with an additive, is applied to a building substrate selected from the group of polystyrene-containing substrates, polyolefin-containing substrates or polyvinyl chloride-containing substrates, and is allowed to dry, the additive containing
 (i) a plasticizer that is liquid at 50° C. or lower, has a boiling point of 100° C. or higher, is capable of dissolving 1 wt % of the building substrate, and that has a solubility parameter δ at 25° C. between 22.5 MPa 1/2  and 11 MPa 1/2  , the plasticizer being selected from the group of esters, ketones, aldehydes, carbonates, aromatic compounds, heteroaromatic compounds, heterocyclic compounds, halogenated hydrocarbons, cyclic unsaturated compounds, terpenes, sulfates, and sulfoxides   (ii) optionally, a filler that has a BET surface area of at least 40 m 2 /g;   (iii) optionally, a biopolymer such as a cellulose ether;   (iv) optionally, a stabilizer such as a protective colloid; and   (v) optionally, a water-insoluble film-forming (co)polymer based on ethylenically unsaturated monomers,   
       wherein the additive is
 a) in the form of a powder obtained by adsorbing the plasticizer (i) on a component selected from a mortar component and the components (ii), (iii), (iv) or (v), said component being in powder form; or 
 b) in the form of a liquid dispersion or powder obtained by mixing the plasticizer (i) with the components (iii) and/or (iv) in pasty, swollen or dissolved form, optionally followed by drying said liquid dispersion; or 
 c) the plasticizer (i), which is added to the mortar when mixing the mortar with water. 
 
     
     
         5 . The process according to  claim 4 , wherein the mortar is a dry mortar or contains a dry mortar component, the additive is added as a powder to the dry mortar or the dry mortar component, and the mortar is mixed with water and optional further liquid components prior to its application. 
     
     
         6 . The process according to  claim 4 , wherein the mortar is a pasty mortar or contains a liquid component, the additive is added as a liquid dispersion to the pasty mortar or to the liquid component, and the mortar is mixed with the liquid dispersion or the liquid component prior to its application. 
     
     
         7 . The process according to  claim 4 , wherein the biopolymer from component (iii) is selected from the group of cellulose ether, starch ether, guar ether, dextrine, alginate, xanthan gum, welan gum, diutan gum, gelatine, casein and soy protein. 
     
     
         8 . The process according to  claim 4 , wherein the stabilizer from component (iv) is a protective colloid and selected from the group of fully or partially saponified polyvinyl alcohols and their derivatives, polyvinyl pyrrolidone, polyvinyl acetal, melamine formaldehyde sulfonates, naphthalene formaldehyde sulfonates, polymerizates of propylene oxide and/or ethylene oxide, including their copolymerizates and block copolymerizates, styrene-maleic acid and vinyl ether-maleic acid copolymerizates. 
     
     
         9 . The process according to  claim 4 , wherein the filler is an inorganic material selected from the group of latent hydraulic binders and pozzolanic materials or inorganic materials that have a BET surface area of at least 40 m 2 /g. 
     
     
         10 . The process according to  claim 4 , wherein the amount of plasticizer based on the total solids content in the mortar is between 0.01 and 2 wt %. 
     
     
         11 . The process according to  claim 4 , wherein the water-insoluble film-forming (co)polymer of ethylenically unsaturated monomers comprises monomers from the group of vinyl acetate, ethylene, acrylate, methacrylate, vinyl chloride, styrene, butadiene, C 4 -C 12  vinyl ester monomers. 
     
     
         12 . The additive according to  claim 1 , comprising components (iii) and/or (iv), wherein the additive is obtained  by mixing the components (iii) and/or (iv) in a solvent to form a pasty, swollen or dissolved mixture and admixing the plasticizer (i) and optionally drying the obtained admixture to form a powder. 
     
     
         13 . Kit of parts containing as one part component (i), as another part component (ii), and, optionally, as further part(s) components (ii), (iii) and/or (iv) of  claim 1 . 
     
     
         14 . Kit of parts containing as one part components (i) and (ii), (i) and (iii) or (i) and (iv) and as the other part component (v) of  claim 1 .