Abstract: Process for preparing a composition comprising a sulfonated lignin, including: preparing a lignin-containing aqueous suspension having a solids content up to about 45 wt % and a pH greater than about 6, by mixing a lignin with water; heating the aqueous suspension between about 65° C. and 160° C.; sulfonating the lignin using a sulfonating agent generating a sulfite ion and/or bisulfite ion, at a temperature of from about 90° C. to 160° C., at a sulfonation pH of from about 6 to 11 and at a molar ratio of sulfonating agent to lignin between about 0.1:1 and 1.5:1 on a sulfite to monomeric lignin sub-unit basis; and cooling the sulfonated lignin-containing resulting mixture. The sulfonated lignin, in aqueous mixture or as a powder, can be used as a dispersant in several products including for instance concrete, grout, mortar, oil-well cement, cement board, gypsum wallboard, agricultural products, drilling fluids, coal slurries.

Abstract: A gypsum slurry includes water, a hydraulic component including calcium sulfate hemihydrate and a linear polycarboxylate dispersant. The linear polycarboxylate anionic dispersant includes a first monomeric repeating unit and a second monomeric repeating unit. The first repeating unit of the linear polycarboxylate dispersant is an olefinic unsaturated carboxylic acid repeating unit or salt thereof. The second repeating unit of the linear polycarboxylate dispersant is a vinyl sulfonate. The slurry can be made into a gypsum panel. Methods of making gypsum slurry and a gypsum panel are also disclosed.

Abstract: A gypsum slurry includes water, a hydraulic component including calcium sulfate hemihydrate and a linear polycarboxylate dispersant. The linear polycarboxylate anionic dispersant includes a first monomeric repeating unit and a second monomeric repeating unit. The first repeating unit of the linear polycarboxylate dispersant is an olefinic unsaturated carboxylic acid repeating unit or salt thereof. The second repeating unit of the linear polycarboxylate dispersant is a vinyl sulfonate. The slurry can be made into a gypsum panel. Methods of making gypsum slurry and a gypsum panel are also disclosed.

Abstract: A gypsum slurry includes water, a hydraulic component including calcium sulfate hemihydrate and a linear polycarboxylate dispersant. The linear polycarboxylate anionic dispersant includes a first monomeric repeating unit and a second monomeric repeating unit. The first repeating unit of the linear polycarboxylate dispersant is an olefinic unsaturated carboxylic acid repeating unit or salt thereof. The second repeating unit of the linear polycarboxylate dispersant is a vinyl sulfonate. The slurry can be made into a gypsum panel. Methods of making gypsum slurry and a gypsum panel are also disclosed.

Abstract: A gypsum slurry includes water, a hydraulic component including calcium sulfate hemihydrate and a linear polycarboxylate dispersant. The linear polycarboxylate anionic dispersant includes a first monomeric repeating unit and a second monomeric repeating unit. The first repeating unit of the linear polycarboxylate dispersant is an olefinic unsaturated carboxylic acid repeating unit or salt thereof. The second repeating unit of the linear polycarboxylate dispersant is a vinyl sulfonate. The slurry can be made into a gypsum panel. Methods of making gypsum slurry and a gypsum panel are also disclosed.

Abstract: The invention relates to copolymers effective as slump retention agents for hydraulic compositions such as cement, mortar and concrete. The copolymers are formed by reacting monomers A, B and C, wherein monomer A is a compound of formula I, monomer B is a compound of formula II, and monomer C is a compound of formula III or IV as shown herein. The copolymers may be used alone or in combination with a water reducing agent or slump retaining agent, e.g. a superplasticizer such as PNS or PMS or a low range water reducer such as lignosulfonate. The copolymer includes a group that is hydrolyzable at elevated pH (e.g. around pH 12) typically present in hydraulic compositions, so that the group hydrolyzes when present in such compositions and forms a charged group that provides extended slump retention properties without introducing undesirable air-entraining characteristics.

Abstract: A process of producing an aqueous solution of a sulfonated melamine-formaldehyde resin. The process comprises condensing melamine and formaldehyde or a precursor of formaldehyde (e.g. paraformaldehyde) in an aqueous mixture having a pH in the range of 8-10 to form a reaction mixture containing a condensation product of melamine and formaldehyde. The condensation product is then reacted in an aqueous mixture having a pH of 8-10, preferably 8-9, with a sulfonating agent to produce a mixture containing a sulfonated condensation product. Finally, polymerizing the said sulfonated condensation product in an aqueous mixture having a pH of 5-7 to form a resin solution. In the process, at least one of the sulfonation step and the polymerizing step is carried out under superatmospheric pressure (generally 5 to 70 p.s.i.) and at an elevated temperature of, in the case of the sulfonating step, 100.degree.-130.degree. C. for a time of 1 to 5 hours or of, in the case of the polymerizing step, 105-150.degree. C.