64results about How to "Improve water reduction" patented technology

The invention discloses a slump retention type solid poly carboxylic acid water reducing agent and a preparation method thereof and belongs to the technical field of concrete admixtures. The slump retention type solid poly carboxylic acid water reducing agent is prepared from an unsaturated polyoxyethylene ether macromonomer, an organic oxidant, an unsaturated carboxylic acid small monomer, an unsaturated ester small monomer, an organic reducer, a chain transfer agent and a neutralizer. The slump retention type solid poly carboxylic acid water reducing agent has remarkable properties of high water reduction and high slump retention under low doping amount, is good in slump retention stability performance and long in durability and is capable of greatly lowering the packaging cost and the transportation cost when being in a solid form.

The invention belongs to the technical field of methods for preparing polycarboxylic acid water reducers. A method for preparing a polycarboxylic acid water reducer comprises the following: a step 1 of esterification, in which a poly(ethylene glycol methyl ether)acrylate macromonomer is synthesized by using methoxy polyethylene glycol and acrylic acid in a molar ratio of 1:1.1 to 1:1.5 at 100 to 120 DEG C, water is separated out in a reaction process, and the molecular weight of the macromonomer is 1,250 to 3,000; and a step 2 of polymerization, in which aqueous solution of the macromonomer is prepared, an unsaturated monomer and a catalyst A are added in turn at 40 to 50 DEG C, the temperature is kept constant at 28 to 40 DEG C, aqueous solution of anhydrous sodium hydrogensulfite or vitamin c is dripped, the concentration of a solid content is kept between 35 to 45 percent by adjusting water content, stirring is stopped, and the solution is allowed to stand for 1 to 1.5 hours, the pH value is kept between 6 and 8 by alkaline reagent after the reaction is finished, and the catalyst A is peroxyacetic acid or potassium peroxydisulfate. The invention has the advantages of low cost, simple process and high product performance.

The invention belongs to the technical field of concrete admixture in building materials, and provides a high-water-reduction high-early-strength type polycarboxylic acid water reducing agent and a pyrogen-free preparation method thereof. Firstly, a high-early-strength type polycarboxylic acid water reducing agent mother liquid is obtained by using a redox initiation system under a pyrogen-free condition, then an optimized early-strength component, a defoaming agent and water are added, and compounding is carried out to obtain the product, wherein the high-early-strength type polycarboxylic acid water reducing agent mother liquid is prepared from unsaturated polyoxyethylene ether (MW=3800-4000), a chain transfer agent, unsaturated acid and / or an unsaturated acid derivative, an oxidant, a reductant and water. The water reducing agent has low mixing amount, and has the advantages of high water reducing rate, good early strength effect, good cement adaptability and the like; moreover, the process does not need additional pyrogen, can be carried out at normal temperature, has less equipment investment and low cost, and is suitable for large-area popularization and application. The water reducing agent can greatly improve the early strength of concrete, improves the template turnover speed, improves the work efficiency, is beneficial for improving constructional engineering quality and improving the production efficiency, reduces energy consumption, and reduces construction costs.