Emulsion polymer compositions and use thereof in low odor waterproofing coatings

Abstract

The invention relates to aqueous polymer dispersions comprising polymerized units issued from the following monomers with related weight proportions based on 100 parts of weight of a)+b): a) 50 to 90% of a monoethylenically unsaturated non-ionic monomer, b) 10 to 50% of vinyl aromatic monomer or methyl methacrylate, c) 1 to 5% of a hydroxy-containing (meth)acrylate, d) 0.1 to 3% of acid monomer selected from d1) acid monomer selected from monocarboxylic or dicarboxylic acid monomers and d2) acid monomer selected from phosphorous-based or sulfur-based strong acid monomers or/and their salts, or from the mixtures of d1) and d2), e) 0.001 to 0.5% of chain transfer agent, and f) 0 to 1% one of internal crosslinker bearing at least two copolymerisable ethylenic unsaturations, the polymer having a Tg measured by DSC from −30 to 0° C. and a gel content of 0 to 60%, formed during polymerization.

1 . An aqueous polymer dispersion wherein said polymer comprises polymerized units issued from the monomers of the following monomeric composition comprising in weight proportions per 100 parts of monomers a)+b) as defined below:
 50 to 90% of at least one monoethylenically unsaturated non-ionic monomer having a homopolymer with a Tg (as measured by DSC at 10° C./min) lower than 0° C., said monomer a) being selected in the group consisting of alkyl (meth)acrylates or vinylic monomers and their mixtures,   b) 10 to 50% of at least one monomer having a homopolymer Tg higher than 80° C., said monomer selected from vinyl aromatic monomers,   c) 1 to 5% of at least one hydroxyl-containing (meth)acrylate,   d) 0.1 to 3% of at least one acid monomer selected from the group consisting of:
 d1) at least one acid monomer selected from a monocarboxylic acid monomer, a dicarboxylic acid monomer and their mixtures, 
 d2) at least one acid monomer selected from phosphorous-based strong acid monomers, sulfur-based strong acid monomers, and their salts, and from the mixtures of the above-defined d1) and d2), 
   e) 0.001 to 2% of at least one chain transfer agent, and   f) 0 to 1% of at least one internal crosslinker bearing at least two copolymerisable ethylenic unsaturations,   the said polymer having a Tg by DSC at 10° C./min from −30 to 0° C. and a gel content of 0 to 60% formed during the polymerization.   
     
     
         2 . The aqueous polymer dispersion of  claim 1 , wherein monomer a) is selected from: alkyl (meth)acrylates with said alkyl being in C4 to C10. 
     
     
         3 . The aqueous polymer dispersion of  claim 1 , wherein monomer b) is vinyl aromatic monomer selected from the group consisting of: styrene, alpha methyl styrene, vinyl toluenes and C1-C2 ring-substituted derivatives of styrene. 
     
     
         4 . The aqueous polymer dispersion of  claim 1  wherein said monomer b) is a mixture of at least one vinyl aromatic monomer with methyl methacrylate. 
     
     
         5 . The aqueous polymer dispersion of  claim 1 , wherein said monomer c) is selected from: hydroxyl alkyl (meth)acrylates with said alkyl being in C2-C4. 
     
     
         6 . The aqueous polymer dispersion of  claim 1 , wherein said monomer d) is an acid monomer d1) selected from the group consisting of: acrylic acid, methacrylic acid, itaconic acid, tetrahydrophtahlic acid (cyclohexene dioic acid), fumaric acid, and maleic anhydride. 
     
     
         7 . The aqueous polymer dispersion of  claim 1 , wherein monomer d) is an acid monomer d2) selected from the group consisting of P-based and S-based acid monomers. 
     
     
         8 . The aqueous polymer dispersion of  claim 1 , wherein said monomer d) is a mixture of d1) and of d2) as defined in  claim 1 . 
     
     
         9 . The aqueous polymer dispersion of  claim 1 , wherein said transfer agent e) is selected from the group consisting of mercaptans. 
     
     
         10 . The aqueous polymer dispersion of  claim 1 , wherein said transfer agent is a mercaptan agent selected from the group consisting of n-dodecyl mercaptan, tert-dodecyl mercaptan and isoalkyl esters of mercapto alkanoic acids in C2-C4. 
     
     
         11 . The aqueous polymer dispersion of  claim 1 , wherein monomer f) is selected from the group consisting of: multifunctional (meth)acrylates which are full esters of polyols with a functionality higher than 2, polyvinyl benzenes (divinyl or trivinyl benzene), polyallyl ethers of polyols with functionality of at least 2, allyl (meth)acrylate, vinyl acrylate, diallyl (meth)acrylate, diallyl phthalate, dicyclopentenyl oxyethyl methacrylate and mixtures thereof. 
     
     
         12 . The aqueous polymer dispersion of  claim 1 , wherein said polymerized units are issued from the following monomers of a monomeric composition in the following weight proportions per 100 parts of weight of a)+b) as defined below:
 60 to 80% of said monomer a) selected from the group consisting of: n-butyl acrylate, 2-ethyl hexyl acrylate, and mixtures thereof,   20 to 40% of said monomer b) selected from the group consisting of: styrene, methyl methacrylate, and mixtures thereof,   0.1 to 4% of said monomer c) selected from the group consisting of: hydroxy ethyl acrylate, hydroxy propyl acrylate, hydroxy butyl acrylate, and mixtures thereof,   0.2 to 2% of said monomer d) being selected from the group consisting of: d1) being acrylic, and methacrylic acid, d2) being acrylamide propane sulfonic acid, and a mixture of d1) and d2),   0.001 to 1% of isoalkyl 3-mercapto propionate, said isoalkyl being in C7 to C9.   
     
     
         13 . The aqueous polymer dispersion of  claim 1 , wherein the said monomeric composition further comprises as surfactant (emulsifier) system g) consisting of the combination of:
 g1) at least one anionic surfactant selected from the group consisting of alkyl sulfates and alkyl ether sulfates with the alkyl ranging from C6 to C20, alkyl of and alkyl ether sulfonates with the alkyl ranging from C6 to C20, alkyl phosphates and phosphinates with the alkyl ranging from C6 to C20, alkyl ether phosphates and phosphinates with the alkyl ranging from C6 to C20, C6-C20 alkyl benzenesulfonates, C4-C18 half esters and diesters of sulfosuccinate, diphenyl oxide disulfonate and combinations thereof, and   g2) at least one non-ionic surfactant selected from the group consisting of ethoxylated fatty alcohol (C10-C40), with an ethoxy unit number ranging from 2 to 100, and ethoxy-propoxy copolymers (EO-PO copolymer) and combinations thereof,   
       with a weight ratio g 1 /g 2  ranging from 0.1/0.9 to 0.9/0.1 and a weight content of g) with respect to a)+b) ranging from 0.5 to 5%. 
     
     
         14 . The aqueous polymer dispersion of  claim 1 , wherein the said monomeric composition further comprises j) at least one pH buffer. 
     
     
         15 . A process for preparing the aqueous dispersion of  claim 1 , wherein said process is an emulsion polymerization process comprising polymerizing with a controlled pH in a range during polymerization from 4 to 11, by adding a buffer agent in or with the monomeric composition. 
     
     
         16 . The process according of  claim 15 , wherein an emulsifier system is present in said monomeric composition consisting of a mixture of two surfactants g1 and g2 as follows:
 g1) at least one anionic surfactant selected from the group consisting of alkyl sulfates and alkyl ether sulfates with the alkyl ranging from C6 to C20, alkyl and alkyl ether sulfonates with the alkyl ranging from C6 to C20, alkyl phosphates and phosphinates with the alkyl ranging from C6 to C20, and alkyl ether phosphates and phosphinates with the alkyl ranging from C6 to C20, and   g2) at least one non-ionic surfactant selected from the group consisting of ethoxylated fatty alcohol (C10-C40), with an ethoxy unit number ranging from 2 to 100 and ethoxy-propoxy copolymers (EO-PO copolymer) and their combinations,   
       with a weight ratio g 1 /g 2  ranging from 0.1/0.9 to 0.9/0.1 and a weight content of g) with respect to a)+b) ranging from 0.1 to 5%. 
     
     
         17 . A coating composition, wherein said coating composition comprises at least one aqueous polymer dispersion as defined in  claim 1 . 
     
     
         18 . The coating composition of  claim 17 , wherein said coating composition is a two-component water-proofing cementitious coating composition further comprising a cement powder in addition to said aqueous polymer dispersion. 
     
     
         19 . The coating composition of  claim 17 , wherein said coating composition further comprises fillers. 
     
     
         20 . (canceled) 
     
     
         21 . (canceled) 
     
     
         22 . (canceled) 
     
     
         23 . (canceled)