Abstract: The present invention provides: a cement admixture which displays excellent cracking inhibition effect and brings about good fluidity even if the quantity of the cement admixture as added is small; and a cement composition comprising this cement admixture. The cement admixture comprises a polyalkylene glycol (A) and a polyalkylene glycol mono(meth)acrylate/unsaturated carboxylic acid-based copolymer (B), wherein: the average molecular weight (X) of the (A) is in the range of 400 to 10,000; the average molecular weight (X) of the (A) and the average molecular weight (Y) of a polyalkylene glycol chain portion of the (B) satisfy 0.9<(X/Y)<1.1; and the weight ratio of the (A) to the (B) is in the range of (A)/(B)=0.02 to 0.3. The cement composition at least comprises the above cement admixture, water, and cement.

Abstract: The present invention provides a cement admixture and a cement composition, both of which displays little dependence of the water-reducibility upon temperature in that these cement admixture and cement composition involve little slump loss at high temperature and little increase in the amount of addition at low temperature. The cement admixture comprises either or both of the following components: copolymer (A) which includes constitutional unit (I) of general formula (1) below and constitutional unit (II) of general formula (2) below as essential constitutional units and may further include constitutional unit (III) of general formula (3) below, wherein the content of constitutional unit (III) is 45 weight % or less of copolymer (A); and copolymer salt (B) which is obtained by further neutralizing copolymer (A) with an alkaline substance.

Abstract: A method for the production of an esterified product is provided which affords an esterified product with high quality by repressing, during the esterification reaction of an alcohol with (meth)acrylic acid, the occurrence of impurities, particularly gel, to be formed owing to the polymerization of the alcohol and the (meth)acrylic acid as raw materials, the esterified product consequently formed, or the mixture thereof.

Abstract: The present invention provides a cement additive which can achieve excellent fluid retainability and has excellent mortar kneadability. The cement additive comprises copolymer (A) having polyalkylene glycol ester unit (I) and carboxylic unit (II) as repeating units, wherein polyalkylene glycol ester unit (I) has an oxyalkylene group with 3 to 7 carbon atoms on an ester bonding moiety.

Abstract: A cement dispersant having excellent ability to prevent slump loss and high water-reducing property which comprises a polycarboxylic acid type polymer having a specific molecular weight distribution, a method for the production thereof, and a cement composition using the dispersant are provided. The cement dispersant comprises as a main component thereof a polycarboxylic acid type polymer (A), having a weight average molecular weight in the range of 10,000 to 500,000 in terms of polyethylene glycol determined by gel permeation chromatography, and having a value determined by subtracting the peak top molecular weight from the weight average molecular weight in the range of 0 to 8,000.

Abstract: The present invention provides a method for producing a cement dispersant having high percentage in water reduction-rate and appropriate air-entraining property. This method for producing a polycarboxylic acid for a cement dispersant is characterized in that alkylene oxide is added at a specific temperature range.

Abstract: A novel cement admixture is provided which fulfills the function as a thickener basically, possesses an ability to inhibit segregation of materials, excels in workability as well, and permits a decrease in the amount of addition while keeping these functions intact. The cement admixture is characterized by comprising a cement additive formed of a polymer resulting from polymerizing a monomer mixture having methyl acrylate as a main component thereof and a cement water reducing agent.

Abstract: The invention provides: a cement admixture which has excellent cement dispersibility and can afford high slump retainability; and a cement composition which has excellent cement dispersibility and high slump retainability. The cement admixture comprises a polycarboxylic acid as an effective component, wherein the polycarboxylic acid is obtained by a process including the steps of: charging "a" parts by weight of a polyalkylene glycol (A) and "b" parts by weight of a (meth)acrylic acid monomer (B) into a reactor in the range of {(a/n.sup.1/2)/b}.times.100.ltoreq.200, wherein n is an average molar number of the added oxyalkylene groups in the polyalkylene glycol (A) and is a number of 1 to 300; carrying out an esterification reaction of the resultant mixture in the reactor, thus obtaining a polyalkylene glycol (meth)acrylate (C); and copolymerizing the resultant polyalkylene glycol (meth)acrylate (C) and the (meth)acrylic acid monomer (B), thus obtaining the polycarboxylic acid.

Abstract: The present invention provides a cement admixture and a cement composition, both of which displays little dependence of the water-reducibility upon temperature in that these cement admixture and cement composition involve little slump loss at high temperature and little increase in the amount of addition at low temperature. The cement admixture comprises the following essential components: either or both of polymer (A) and polymer salt (AA), wherein polymer (A) includes constitutional unit (I) of general formula (1) below as an essential constitutional unit, and polymer salt (AA) is obtained by further neutralizing polymer (A) with an alkaline substance; and either or both of polymer (B) and polymer salt (BB), wherein polymer (B) includes constitutional unit (II) of general formula (2) below as an essential constitutional unit, and polymer salt (BB) is obtained by further neutralizing polymer (B) with an alkaline substance.

Abstract: A method for the dispersion of cement, which comprises incorporating in a cement composition consisting at least of cement and water a cement dispersing agent formed of a polymer obtained by polymerizing a monomer component containing an alkoxy polyalkylene glycol mono(meth)acrylic ester monomer produced by the interesterification of an alkoxy polyalkylene glycol and a (meth)acrylic ester. A cement composition comprising the cement dispersing agent, cement and water.

Abstract: A cement composition excelling in the slump retaining property which comprises at least cement admixture comprising as a main ingredient thereof (I) a copolymer (A) of short-chain polyalkylene glycol (meth)acrylate (a), a long-chain polyalkylene glycol (meth)acrylate (b), a carboxylic acid monomer (c), and a monomer copolymerizable with the monomers mentioned above or a salt of the copolymer (B), (II) a copolymer (A.sub.1) of the monomers (a), (c), and (d) mentioned above or a salt thereof, (III) a mixture of a copolymer (A.sub.1) of the monomers (a), (c), and (d) mentioned above or a salt (B.sub.1) of thereof with a known cement admixture, or (IV) a polycarboxylic acid based polymer (A.sub.3) manifesting to a calcium sulfoaluminate based expansive additive an adsorption ratio of not less than 90% in 5 minutes at room temperature when added in an amount of 0.1% by weight as solids or a salt (B.sub.

Abstract: The present invention provides a cement additive its production process and cement composition achieving excellent slump loss prevention capability. As a cement additive, there can be a copolymer (A-1) comprising an unsaturated polyalkylene glycol ether-based monomer (I), maleic acid-based monomer (II) and other monomer (III) copolymerizable with these monomers, the monomer (I)/monomer (II)/monomer (III) weight ratio being 50-99/50-1/0-49 and the weight average molecular weight of the copolymer (A) being 10,000 to 100,000 in terms of polyethylene glycol measured by gel permeation chromatography, or a copolymer (A) with an antifoaming agent (B), wherein the copolymer (A) comprises polyalkylene glycol ether-based units and dicarboxylic acid-based units as repeating units.

Abstract: A new block copolymer, which is excellent with regard to abilities such as dispersibility, chelatability, and scale inhibitability, includes a polyalkylene glycol structural unit and a polyglyoxylate structural unit. This block copolymer, for example, can be produced by carrying out a polymerization reaction between a polyalkylene glycol and a glyoxylic acid-based monomer in the presence of a catalyst in a polymerization reaction system having a water content of about 30 mol % or less relative to the polyalkylene glycol, and used as a cement dispersant, pigment dispersant, water-treating agent, or detergent builder.

Abstract: A novel acrylic ester which is represented by general formula (2) ##STR1## wherein R.sub.1 and R.sub.2 independently represent a hydrogen atom or an organic residue, R.sub.3 represents an organic residue, n is a positive number among 1 to 3, and m is a positive number among 1 to 100 and which is applicable to various uses, is obtained by reacting an acrylic ester of general formula (3) ##STR2## wherein R.sub.1 represents a hydrogen atom or an organic residue, and R.sub.3 represents an organic residue, with a cyclic ether compound of general formula (4) ##STR3## wherein R.sub.2 represents a hydrogen atom or an organic residue, and n is a positive number among 1 to 3. Moreover, a novel acrylic acid derivative whose use is even wider is obtained by hydrolyzing the acrylic acid derivative.

Abstract: An admixture for modifying the fluidity of a cementitious mixture comprises a cement-dispersing agent which is an aqueous solution of polymer, in which solution an oxyalkylene-based defoaming agent is dissolved or dispersed in particles of no greater that 20 .mu.M diameter. The polymer is preferably a polymer which comprises units derived from unsaturated carboxylic acid monomer and the polymer is preferably prepared in the presence of the defoaming agent. Particular addition copolymers give particularly good results. The admixture permits good control of the fluidity of cementitious compositions and has extended shelf life.

Abstract: A cement dispersant having as a main component thereof at least one polymer selected from the group consisting of polymers obtained from (A) 0.1 to 100 mol % of a sulfonic acid type monomer represented by the formula I: ##STR1## wherein R stands for hydrogen atom or methyl group, X stands for hydrogen atom, a monovalent metallic atom, a divalent metallic atom, ammonium group, or an organic amine group, A and B independently stand for an alkylene group of 2 to 4 carbon atoms, m stands for 0 or an integer of the value of 1 to 100, and the alkylene oxide group of 2 to 4 carbon atoms in the portion, (AO).sub.m may be bound in any desired sequence, and (B) 99.9 to 0 mol % of olther monomer copolymerizable with said sulfonic acid type monomer, and polymers obtained by neutralizing said polymers with an alkaline substance, a cement composition containing the dispersant and a method for dispersing a cement.

Abstract: A cement dispersant containing a water-soluble polymer containing at least 10 mol % of structural units represented by the general formula I: ##STR1## wherein X is H or CH.sub.2 R.sup.1, R.sup.1 is H or COO--[--A).sub.m B).sub.n ]H, R is H, CH.sub.3, or COO--[--A).sub.m B).sub.n ]H (providing that R is H where X is CH.sub.2 R.sup.1), A is iminoalkylene having 2 to 4 carbon atoms, B is oxyalkylene having 2 to 4 carbon atoms, m is an average number in the range of 0.1 to 10, n is O or an average positive number not more than 100, --A).sub.m may be in a linear or branched configuration, wherein the sequence of A and B in the segment in parenthesis may be regular or random.

Abstract: A cement dispersant having as a main component thereof at least one polymer selected from the group consisting of polymers obtained from (A) 0.1 to 100 mol % of a sulfonic acid type monomer represented by the formula I: ##STR1## wherein R stands for hydrogen atom or methyl group, X stands for hydrogen atom, a monovalent metallic atom, a divalent metallic atom, ammonium group, or an organic amine group, A and B independently stand for an alkylene group of 2 to 4 carbon atoms, m stands for 0 or an integer of the value of 1 to 100, and the alkylene oxide group of 2 to 4 carbon atoms in the portion, (AO).sub.m may be bound in any desired sequence, and (B) 99.9 to 0 mol % of other monomer copolymerizable with said sulfonic acid type monomer, and polymers obtained by neutralizing said polymers with an alkaline substance, a cement composition containing the dispersant and a method for dispersing a cement.