Nippon Shokubai Co., Ltd.

Mbt Holding Ag

Nippon Shokubai Kagaku Kogyo Co., Ltd.

Other

Sumitomo Osaka Cement Co., Ltd.

Technical University of Munich

Nippon Shokubai Kagaku, Co., Ltd.

Tsuyoshi Hirata

Tsutomu Yuasa

Hiromichi Tanaka

Toru Uno

Yoshiyuki Onda

Koichiro Nagare

Akihiko Yamashita

Hideyuki Tahara

Noboru Sakamoto

Hirokatsu Kawakami

Tomotaka Nishikawa

Tomiyasu Ueta

Katsuhisa Shiote

Hiroshi Ito

Yoshio Tanaka

Tsuneo Tsubakimoto

Akira Ohta

Hirokazu Niwa

Hiroko Izukashi

Syogo Iwai

Shigeru Yamaguchi

Shogo Iwai

Hiroya Kobayashi

Toru Inaoka

Masaya Yamamoto

Hiroshi Yamazaki

Akira Ono

Yoshinori Sano

Yuichi Kita

Takuya Saeki

Yasuhiko Sato

Takashi Tomita

Shorbu Shioji

Hideaki Nagano

Hideyuki Nishibayashi

Keiji Yurugi

Koichi Nakagawa

Mitsuaki Makino

Katsuyuki Kono

Toshio Hayashiya

Yasuhiro Mori

Masami Hattori

Daisuke Imai

Johann Plank

Hisashi Inokawa

Naoko Hirano

Hiroshi Mitsukawa

A copolymer that has sufficient dispersibility to various kinds of cements, including those having low fluidity (difficult cement). The copolymer is obtained by polymerizing monomer components including an unsaturated (poly)alkylene glycol ether monomer (a), an unsaturated carboxylic acid monomer (b), and an unsaturated cross-linkable monomer (c) or an unsaturated cross-linkable monomer (d). The unsaturated cross-linkable monomer (c) is allyl itaconate or allyl citraconate, or ester thereof. The unsaturated cross-linkable monomer (d) is an ester obtained by reaction of at least one acid, selected from the group consisting of (meth)acrylic acid, maleic acid, fumaric acid, itaconic acid, and citraconic acid and ester derived from the acids, with a (poly)alkylene glycol or a (poly)alkylene glycol ether.

Copolymer for dispersant for cement, dispersant for cement, and cement composition

To provide an ultrarapid hardening cement composition with high strength, the composition having: excellent fluidity; excellent usable time; and excellent initial strength under low temperature atmosphere as well as under general temperature atmosphere, and improving strength and durability of a hardening product of the composition. An ultrarapid cement hardening composition comprising: an ultrarapid hardening cement (A) comprising a calcium aluminate; and a cement dispersant (B), wherein the cement dispersant (B) comprises a copolymer having: a repeating unit derived from a monomer represented by the following formula (1) and formula (2) as defined in the specification.

Ultrarapid hardening cement composition and dispersant for ultrarapid hardening cement composition

The dispersant of the present invention comprises at least one component unit derived from kraft lignin and/or its salt and at least one component unit derived from at least one water-soluble monomer. The novel lignin derivative of the present invention comprises at least one component unit derived from kraft lignin and/or its salt, at least one polyoxyalkylene chain, and at least one anionic functional group.

Dispersant using kraft lignin and novel lignin derivative

It is an object of the present invention, which has been made in view of the above-mentioned state of the art, to provide a cement admixture capable of improving the water-reducing ability of cement compositions and the like and enhancing the strength and durability of hardened products produced therefrom and further capable of adjusting the viscosity of such compositions so as to facilitate the works at the sites of handling the same, as well as a method of producing such cement additive. A cement admixture comprising a polycarboxylic acid polymer and a nitrogen atom-containing compound having non-amide bond, wherein the mass ratio (A/B) between the mass (A) of said polycarboxylic acid polymer and the mass (B) of said nitrogen atom-containing compound having non-amide bond satisfies the relation 200&#x3e;(A/B)&#x3e;1.

Cement admixture and production method thereof

It is an object of the present invention to provide a polycarboxylic acid polpolymer which improves the water reducing capacity and workability of cement compositions and the like and making them easier to handle when the fluidity and water reducing capacity are at the same levels, a method of producing the copolymer, and a cement additive and a cement composition comprising the copolymer. The present invention is further to provide a polycarboxylic acid copolymer and a cement additive which are capable of improving the strength and durability of hardening products of cement compositions, hence can advantageously be used in ultrahigh strength concrete. The present invention is polycarboxylic acid copolymers having high water reducing capacity, reducing the viscosity of cement compositions and improving the workability in applying cement. The present invention is directed to a polycarboxylic acid copolymer which is obtained by copolymerization of monomer components comprising a polyalkyleneimine unsaturated monomer (A1) and an unsaturated carboxylic acid monomer (B).

Polycarboxylic acid copolymer, production method and use thereof

The present invention provides: a production process for an alkylene oxide addition product, by which a high-molecular alkylene oxide addition product can be obtained with ordinary production facilities while the formation of by-products is suppressed; and production processes for derivatives from the alkylene oxide addition product. The present invention production process for an alkylene oxide addition product comprises the step of carrying out an addition reaction of an alkylene oxide to a hydroxyl-group-containing saturated compound in order to obtain the alkylene oxide addition product; with the production process being characterized by further comprising: the initial step of causing the alkylene oxide to add to the hydroxyl-group-containing saturated compound in an amount of not larger than 20 mols on average of the alkylene oxide per 1 mol of the hydroxyl-group-containing saturated compound to thereby obtain an alkylene oxide low-mol-addition product; and the molar-degree-of-polyaddition-adjusting step of causing the alkylene oxide to further add to the alkylene oxide low-mol-addition product as obtained in the initial step; wherein a portion of the entirety of the alkylene oxide low-mol-addition product as obtained in the initial step is used in the molar-degree-of-polyaddition-adjusting step.

Production processes for alkylene oxide addition product and its derivatives

There are provided an admixture for cement which enhances water reducing property and flowability of a cement composition, and is excellent in slump retaining performance to retain the flowability with time, a polycarboxylic acid-based polymer for an admixture for cement suitable therefor, a producing method thereof, and a cement composition. One admixture for cement of the present invention contains copolymers (A) and (B) as an essential component, weight average molecular weights (AMw and BMw) of copolymers (A) and (B) are AMw&#x3e;BMw, or peaktop molecular weights (AMp and BMp) of copolymers (A) and (B) are AMp&#x3e;BMp. Another admixture for cement of the present invention contains a polycarboxylic acid-based polymer having a lower molecular weight side area ratio P of 50 to 87%.

Admixture for cement

The cement admixture of the present invention can provide viscosity decreasing ability as well as a high dispersing ability and slump loss preventing ability even in a high water reducing ratio range. The above-mentioned cement admixture comprises three components of a copolymer (A) containing a constituent unit (I) derived from the unsaturated (poly)alkylene glycol ether monomer (a) and a constituent unit (II) derived from a maleic acid monomer (b), a specific unsaturated (poly)alkylene glycol ether monomer (a) and a non-polymerizable (poly)alkylene glycol (B) having no alkenyl group.

Cement admixture, cement composition and method for laying work the same, and method for producing cement hardened product

The cement admixture of the present invention can improve the workability by displaying sufficient viscosity decreasing ability and initial dispersing ability even under a low temperature environment as well as high dispersing ability and dispersion retaining ability even in a high water reducing ratio range. The above-mentioned cement admixture comprises four components of a copolymer (A) containing a constituent unit (I) derived from the unsaturated (poly)alkylene glycol ether monomer (a) and a constituent unit (II) derived from a maleic acid monomer (b), a specific unsaturated (poly)alkylene glycol ether monomer (a), a non-polymerizable (poly)alkylene glycol (B) having no alkenyl group, and a polymer (C) having an oxyalkylene group or a polyoxyalkylene group and a carboxyl group, which is different from the copolymer (A).

Cement admixture and cement composition

Disclosed are the following: a cement dispersant which is excellent in initial dispersibility and further in flow retainability of cement, because of using a polymer having a proper molecular weight distribution; a process for producing this cement dispersant; and a cement composition using this cement dispersant. The cement dispersant comprises a water-soluble polymer (P) as a main component, and is characterized by displaying an area proportion (a value (A&#x2212;B) given by subtracting an area ratio B of a lower molecular weight side portion from an area ratio A of a higher molecular weight side portion) in the range of 13 to 60%.

Cement dispersant, its production process, and cement composition using the cement dispersant

It is an object of the present invention to provide a cement admixture capable of exhibiting high cement dispersing ability at low addition levels, in particular capable of displaying excellent initial dispersing ability and dispersion retaining ability even in a high water reducing ratio range, and a cement composition in which this admixture is used. A cement admixture comprising

The admixtures for a cementitious composition of the invention, which have the above-mentioned constitutions, can suitably be used in cement pastes, mortar, concrete and like cement compositions and can stabilize the amount of air entrained with the lapse of time and thus facilitate the quality control of cement compositions and, further, can improve the workability of cement compositions owing to their excellent dispersing capacities. The cement compositions of the invention which comprise such admixture for a cementitious composition are excellent in water-reducing ability and workability and can give hardened products excellent in strength and durability and, further, can stably maintain the amount of air entrained without allowing increases in the amount of air even when the time of kneading is prolonged in the production.

It is an object of the present invention to provide a cement admixture which can show not only a high dispersing ability and a slump loss preventing effect but also a viscosity reducing effect and can show these characteristics even in the high water reduction ratio range, and a cement composition in which this admixture is used. A cement admixture comprising,

It is an object of the present invention to provide a polycarboxylic acid copolymer which improves the water reducing capacity and workability of cement compositions and the like and making them easier to handle when the fluidity and water reducing capacity are at the same levels, a method of producing the copolymer, and a cement additive and a cement composition comprising the copolymer. The present invention is further to provide a polycarboxylic acid copolymer and a cement additive which are capable of improving the strength and durability of hardening products of cement compositions, hence can advantageously be used in ultrahigh strength concrete. The present invention is still further to provide a method of producing polycarboxylic acid copolymers having high water reducing capacity, reducing the viscosity of cement compositions and improving the workability in applying cement. The present invention is directed to a polycarboxylic acid copolymer which is obtained by copolymerization of monomer components comprising a polyalkyleneimine unsaturated monomer (A1) and an unsaturated carboxylic acid monomer (B).

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Kobe, Japan

Tsuyoshi Hirata