POLYMERIC COMPOSITIONS CONTAINING MODIFIED POLYVINYL ALCOHOLS
The invention relates to polymeric compositions containing modified polyvinyl alcohols embodied in the form of the aqueous dispersion thereof or water-redispersible powders based on homo or mixed polymerisates of one or several monomers of a group comprising linear or branched alkylcarboxylic acid vinyl esters containing from 1 to 15 C atoms, methacrylic acid esters and alcohol acrylic acid esters containing from 1 to 15 C atoms, vinyl aromatics, olefins, dienes and vinyl halogenides. The inventive compositions are characterised in that the modified polyvinyl alcohols contained therein exhibit a latent carboxylic acid function and/or comprise phosphorus-containing comonomer units.
1 - 13 . (canceled)
14 . A water redispersible polymer powder, comprising:
a) base polymer particles prepared by polymerizing monomers comprising at least one monomer selected from the group consisting of vinyl esters of optionally branched C 1-15 alkylcarboxylic acids, (meth)acrylic esters of C 1-15 alcohols, vinyl aromatics, monoolefins, dienes, and vinyl halides; and
b) at least one modified polyvinyl alcohol protective colloid selected from the group consisting of polyvinyl alcohol copolymers containing copolymer units having a latent carboxylic acid functionality, copolymer units containing phosphorous, and copolymers containing both copolymer units having a carboxylic acid functionality and copolymer units containing phosphorus.
15 . The polymer composition of claim 14 , wherein the modified polyvinyl alcohols comprise one or more comonomer units selected from the group consisting of methacrylic esters and acrylic esters of C 1-15 alcohols.
16 . The polymer composition of claim 14 , wherein the modified polyvinyl alcohols comprise one or more comonomer units selected from the group consisting of vinylphosphonic acid, and methacrylic esters and acrylic esters of polyalkylene glycols which are end-modified by phosphoric acid and contain from 1 to 100 C 2-4 oxyalkylene units.
17 . The polymer composition of claim 14 , obtained by means of spray drying an aqueous polymer dispersion stabilized with at least one modified polyvinyl alcohol having a latent carboxylic acid function or a modified polyvinyl alcohol comprising phosphorus-containing comonomer units, in the presence of partially hydrolyzed, unmodified polyvinyl alcohol as an atomization aid.
18 . A process for preparing a water redispersible polymer powder of claim 14 , comprising polymerizing a monomer mixture comprising at least one monomer selected from the group consisting of vinyl esters of optionally branched C 1-15 alkylcarboxylic acids, (meth)acrylic esters of C 1-15 alcohols, monolefins, dienes, vinyl aromatics, and vinyl halides, in the presence of at least one protective colloid selected from the group consisting of modified polyvinyl alcohol copolymers containing copolymer units having a latent carboxylic acid functionality, copolymer units containing phosphorous, and copolymers containing both copolymer units having a carboxylic acid functionality and copolymer units containing phosphorus, and spray drying to form a polymer powder.
19 . The process of claim 18 , wherein a further polyvinyl alcohol protective colloid different from said modified polyvinyl alcohol copolymer is present during polymerization.
20 . The process of claim 18 , wherein prior to spray drying, a further protective colloid is added.
21 . The process of claim 20 , wherein said further protective colloid comprises a polyvinyl alcohol homopolymer or copolymer not containing latent carboxylic acid units and not containing units containing phosphorous.
22 . The process of claim 20 , wherein said further protective colloid comprises at least one protective colloid selected from the group consisting of polyvinyl alcohol copolymers containing copolymer units having a latent carboxylic acid functionality, copolymer units containing phosphorous, and copolymers containing both copolymer units having a carboxylic acid functionality and copolymer units containing phosphorus.
23 . A process for the preparation of a water redispersible polymer powder of claim 14 , comprising supplying a polymer dispersion stabilized with one or more protective colloids and spray drying to form a polymer powder, and prior to spray drying, adding a further protective colloid selected from the group consisting of modified polyvinyl alcohol copolymers containing copolymer units having a latent carboxylic acid functionality, copolymer units containing phosphorous, and copolymers containing both copolymer units having a carboxylic acid functionality and copolymer units containing phosphorus.
24 . A building construction composition comprising a mineral filler and a redispersible polymer powder of claim 14 .
25 . A building construction composition comprising a hydraulically settable binder and a redispersible polymer powder of claim 14 .
26 . The building construction composition of claim 25 which is alkaline such that latent carboxylic acid units in the redispersible polymer powder are at least partially hydrolyzed, liberating alcohol.
27 . The building construction composition of claim 25 , wherein said hydraulically settable binder is selected from the group consisting of gypsum, lime, cement, waterglass, and mixtures thereof.
28 . A binder-containing paper a textile product containing at least one redispersible polymer powder of claim 14.