Sika Technology Ag

Sika Schweiz Ag

Sika Ag, Vorm. Kaspar Winkler & Co.

Empa

Empa Eidgenossische Materialprufungs-und Forschungsanstalt

Irene Schober

Ulf Velten

Ueli Sulser

Jürg Widmer

Theodor A Bürge

Christian Bürge

Urs Mäder

Theodor A Burge

Jurg Widmer

Theodor A B&uuml;rge

Thomas Haack

Hugo Olivares

Pedro Gallegos

Anna Krapf

Urs Maeder

J&uuml;rg Widmer

Tobias Heck

Michael Richter

Lili Arancibia

Dagmara Jankowska

Christian M Burge

Christian M BÜRGE

The present invention relates to water-soluble modified lignins preparable by enzymatic reaction of at least one water-insoluble lignin with at least one organic compound which possesses at least one group selected from primary or secondary amino group, hydroxyl group and phenyl group and has an average molecular weight in the range from 75 to 2500 g/mol. The water-soluble modified lignins are preparable under mild conditions in a simple process. They can be used as dispersants for mineral binder compositions, where they act as plasticizers and in so doing prolong the setting time to much less of an extent than the water-insoluble lignins used in their preparation.

Enzymatically modified lignins

The invention relates to a method for the production of a polymer (P) comprising amide and ester groups, whereby, in a first step, a homo- or co-polymer (P1) of (meth)acrylic acid is reacted with a monohydroxy compound (E) at a temperature of up to 200&#xb0; C., such that, in addition to ester groups, anhydride groups are formed and, in a second step, the anhydride groups formed in the first step are reacted with a monoamine compound (A) at temperatures significantly below 100&#xb0; C. The invention further relates to polymers produced by the above method, the use thereof in hydraulic-setting compositions and said hydraulic-setting compositions before and after hardening by addition of water.

Polymer comprising amide and ester groups, method for production and use thereof

Described are polymers and cement admixtures which reduce drop in fluidity with time. Said admixture comprises at least one polymer of the present invention and at least one polymer A. The polymer of the present invention comprises side chains of which at least 10 weight-% can be cleaved in alkaline medium. The polymer of the present invention is an acrylic polymer which comprises side chains connected to the backbone by ester linkages. These side chains may be alkyl, hydroxy alkyl, cycloalkyl or polyoxyalkylene groups. Polymer A is a cement dispersing agent. The combination of polymer A with the polymer of the present invention in a weight ratio of 0.1:10-10:1, and preferably 1:10-10:1 reduces the drop in fluidity with time of cementitious compositions.

Cement admixture for improved slump life

Described are polymers and cement admixtures which reduce drop in fluidity with time. Said admixture comprises at least one polymer of the present invention and at least one polymer A. The polymer of the present invention comprises side chains of which at least 10 weight-% can be cleaved in alkaline medium. The polymer of the present invention is an acrylic polymer which comprises side chains connected to the backbone by ester linkages. These side chains may be alkyl, hydroxy alkyl, cycloalkyl or polyoxyalkylene groups. Polymer A is a cement dispersing agent. The combination of polymer A with the polymer of the present invention in a weight ratio of 0.1:10&#x2013;10:1, and preferably 1:10&#x2013;10:1 reduces the drop in fluidity with time of cementitious compositions.

Polymers for cement dispersing admixtures, which show different performing properties in concrete are described. All polymers are based on a composition of reactants, namely a) a poly(acrylic acid), b) a polyalkyleneglycol-monoalkylether and, optionally c) a &#x3b1;-amino-polyalkylene-glycol-&#x3c9;-alkylether and/or d) a primary or secondary amine. By keeping the composition of reactants constant and varying only the reaction time, polymers with different properties can easily be achieved. Such polymers are suitable for pre-cast, readymix or for increasing workability over time, just depending on reaction time. Polymers of the invention can be used as single polymer or in polymer blends. For this, the kinetics of the used polymer analogous condensation reaction was intensively studied. Additionally, the benefit of amines as reactant regarding stability and hydrolysis velocity of cleavable side groups was investigated.

Polymers for cement dispersing admixtures

Cement dispersing polymers for high flow, high strength and selfcompacting concrete

Novel water-soluble linear copolymers of N-vinylamides with monomeric addition products of amines, amino acids, amino groups containing aromatic sulfonic acids, amino alcohols of maleic anhydride as well as maleic esters of polyoxyalkyleneglycols or their monoethers. There is also described the process for the preparation of these copolymers. The copolymers are useful as fluidizers in water containing solid matter suspensions.

Water-soluble copolymers, a process for their preparation and their use

Growing community of inventors

Zurich, Switzerland

Irene Schober