Nippon Shokubai Co., Ltd.

Sumitomo Osaka Cement Co., Ltd.

Nittetsu Cement Co., Ltd.

Nippon Steel and Sumikin Cement Co., Ltd.

Hirokatsu Kawakami

Tsuyoshi Hirata

Tsutomu Yuasa

Takashi Tomita

Hiromichi Tanaka

Akira Ono

Tomohiro Kanazawa

Koichiro Nagare

Naohiko Itayama

Hiroko Okochi

Hirokazu Niwa

Kazutaka Otsuki

Akiko Yamauchi

Masami Hattori

Daisuke Imai

Hisashi Inokawa

The present invention aims to provide a polycarboxylic acid copolymer which is excellent in various properties, in particular dispersibility, and is useful in various uses such as dispersants and admixtures for cement. The present invention also aims to provide a dispersant for cement, an admixture for cement, and a cement composition each containing the above polycarboxylic acid copolymer. The polycarboxylic acid copolymer of the present invention includes a structural unit (I) derived from an unsaturated polyalkylene glycol monomer (a) and a structural unit (II) derived from an unsaturated carboxylic acid monomer (b). The copolymer has a weight average molecular weight (Mw) of 5000 to 25000. The copolymer includes a dimer including two units of the unsaturated polyalkylene glycol monomer (a) bonded to each other, and has an area percentage of the dimer of 7% or higher.

Polycarboxylic copolymer, cement dispersion agent, cement admixture, and cement composition

The present invention has an object to provide a polymer-containing composition for dispersants for cement which exhibits higher cement dispersibility even when used in a small amount, and can provide high flowability to a cement composition such as mortar and concrete and stably maintain this high flowability for a certain period, and to provide a production method thereof. The polymer-containing composition for dispersants for cement includes a polymer including a repeating unit derived from an unsaturated polyalkylene glycol ether monomer (I) having a specific structure and a repeating unit derived from an unsaturated carboxylic acid monomer (II) having a specific structure, and is prepared by polymerizing an unsaturated polyalkylene glycol ether monomer (I)-containing composition that includes specific amounts of specific components.

Polymer composition for cement dispersant and method for producing same

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

To provide an ultrafine particle grouting composition which is excellent in dispersibility and dispersion retainability and can be easily injected into minute spaces between particles of grounds, rock cracks, and the like. An ultrafine particle grouting composition comprising ultrafine particle cement, wherein the ultrafine particle grouting composition is at least one selected from the group consisting of the following (i) and (ii): (i) the ultrafine particle grouting composition comprises ultrafine particle cement (A) and a polycarboxylic acid dispersant (C), and the ultrafine particle cement (A) comprises blast furnace slag and gypsum, and the ultrafine particle cement (A) has 10% by volume or less of particles having a particle diameter of 16 &#x3bc;m or more in powder form of the cement; and (ii) the ultrafine particle grouting composition comprises ultrafine particle cement (B) and a polycarboxylic acid dispersant (D), and the ultrafine particle cement (B) comprises 2 to 25% by weight of cement clinker containing 5% by weight or less of 3CaO.AlO, 74 to 97% by weight of blast furnace slag, and 1 to 5% by weight of gypsum, and the ultrafine particle cement (B) has 60 to 80% by volume of particles having a particle diameter of 1 to 5 &#x3bc;m in powder form of the cement.

Ultrafine particle grouting composition

The objective of the present invention is to provide a concrete composition in which the amount of air entrained can be maintained stably and which is excellent in strength and durability, a concrete composition which is excellent in freeze-thaw durability owing to the good quality of foams and is excellent in air content stability with time and which can form curing products excellent in strength and durability, a method of producing such concrete composition, and a cement admixture.

Concrete composition method of producing concrete compositions and cement admixture

A polycarboxylic acid cement dispersant that can exhibit high dispersing ability and allow deforming in early stages in the case of producing concrete products, whereby the turnover of a formwork is increased so as to improve productivity, and the method of producing such as concrete product are provided. The polycarboxylic acid cement dispersant which provides a cement composition having a penetration resistance value exponent of 55 MPa or more and a slump retention exponent of 80% or more, and the method of producing a concrete product which makes use of a copolymer derived by using monomer components comprising the monomer (A) as polyalkylene glycol unsaturated monomer, the monomer (B) as unsaturated carboxylic monomer, and the monomer (C) as sulfonic acid group-containing monomer.

Polycarboxylic acid cement dispersant and method for producing concrete secondary product

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.

Cement admixture and cement composition

There is provided: a (meth)acrylic acid (salt) polymer which has high properties and is little colored; and a process which can produce this polymer with a high polymerization conversion without causing the corrosion of the reaction vessel. When a (meth)acrylic acid (salt) polymer is obtained by carrying out polymerization of an unsaturated monocarboxylic monomer (a) and an unsaturated polyalkylene glycolic monomer (b) with a polymerization initiator, either a redox polymerization initiator including hydrogen peroxide and a reducing agent is used as the polymerization initiator in a specific amount, or the unsaturated polyalkylene glycolic monomer is subjected to the polymerization in the form of an esterification reaction product as obtained by a process including the steps of: esterifying the unsaturated monocarboxylic monomer and a polyalkylene glycol in a specific charging ratio in the presence of an acid catalyst in a manner for a portion of the residual unsaturated monocarboxylic monomer as a starting raw material to remain; and then neutralizing the acid catalyst and the residual unsaturated monocarboxylic monomer (a) with a basic substance after the esterification; and the polymerization is carried out under conditions where the pH during the polymerization is in the range of 3.2 to 7.0.

(Meth) acrylic acid (salt) polymer and its production process

Cement additive

Cement additive, cement composition and polycarboxylic acid polymer

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.

Growing community of inventors

Izumiotsu, Japan

Hirokatsu Kawakami