44results about How to "Prolong the retarding time" patented technology

The invention discloses a modified starch water reducing agent and a preparation method and a use method thereof; with natural starch as a main raw material, the modified starch water reducing agent is prepared through oxidative degradation and grafting copolymerization reaction with a mixed monomer and has the characteristics of high water reducing rate, strong adaptability, good delayed coagulation effect and good compatibility with other additives, the water reducing rate can reach 26-28%, and the delayed coagulation time is 3-4 hours. When the product prepared by the method is in cooperation use with a polycarboxylate-type water reducing agent, can increase the delayed coagulation time of the polycarboxylate-type water reducing agent to reach 4-5 hours, can effectively prevent the polycarboxylate-type water reducing agent from generating water overflowing, segregation and other phenomena, and improves the adaptability of the polycarboxylate-type water reducing agent on mud-containing dinas.

This invention relates to a compound super-retarder of cement, which takes industrial phosphate and PBTC as the raw materials and produces it according to an ordinary method, which can be mixed with different cements and increases post strength and durability of concrete, so it's used in summer installation, concrete needing adjusting operation time and large volume of concrete pouring or mixing pre-mixed mortar.

The invention discloses a special water reducing agent for gypsum. The special water reducing agent is prepared from allyl ether, acrylic acid and allyl phosphonate which are used as monomers as well as a cationic monomer, an alkali neutralizer and an initiator through copolymerization reaction. The special water reducing agent for the gypsum is high in water reducing rate, strong in delayed coagulation and good in adaptability to the gypsum, avoids formaldehyde pollution in the production process, and is particularly adaptive to building gypsum and other gypsum products.

The present invention discloses a polycarboxylic acid water reducing agent preparation method, and a retarder compounded with the prepared polycarboxylic acid water reducing agent. According to the method, a water phase free radical copolymerization reaction is performed in water by using acrylic acid and other unsaturated acids as a small monomer, using isobutylene alcohol polyoxyethylene ether as a large monomer, using persulfate as an initiator, and using thioglycolic acid and/or mercaptopropionic acid as a chain transfer agent. According to the present invention, the retarder comprises, byweight, 75-90 parts of the polycarboxylic acid water reducing agent (calculated as the weight of the effective component), 1-10 parts of sodium tripolyphosphate, 10-25 parts of citric acid, and 1-10parts of a calcium increasing agent, has good retarding effect, and can significantly prolong the retarding time of desulfurized building gypsum, such that the desulfurized gypsum can overcome the drawbacks that the construction requirement cannot be met due to the rapid solidification, and the strength loss of the desulfurized gypsum after solidification is low.

The invention discloses a quick repairing material for magnesium phosphate cement and a preparation method thereof. The quick repairing material for magnesium phosphate cement, as a composite, is mainly made from, by weight, 25 parts of magnesium oxide, 15-20 parts of monopotassium phosphate, 0.5-1.5 parts of ethylenediamine tetraacetic acid dipotassium salt dihydrate, and 5-10 parts of water. Theethylenediamine tetraacetic acid dipotassium salt dihydrate is used herein as a retardant to replace borax used in the traditional magnesium phosphate cement. The quick repairing material has good retarding effect; setting time of the magnesium phosphate repairing system is greatly extended; the magnesium phosphate repairing system ensures early strength of a magnesium phosphate cement sample, and late strength of the magnesium phosphate repairing system is improved to certain extent.

The invention discloses a modified maltose syrup retarder as well as a preparation method and application thereof. The modified maltose syrup retarder is prepared from maltose syrup, acrylic acid, an activating agent, unsaturated acid, esters, acrylamide, an initiator, deionized water and liquid caustic soda in a mass part ratio of (79-157):(10-40):(0.5-3.2):(40-80):(20-40):(20-40):(1-5):(500-750):(8-15). The preparation method comprises the following steps: putting malt syrup and acrylic acid into a No.1 reaction kettle according to the mass part ratio of (4-8):1, further adding an activating agent which is 0.5-2% of the total amount of the malt syrup, heating to 70-90 DEG C, stirring and reacting for 4 hours, and cooling to room temperature to obtain an intermediate product A; then adding the intermediate product A, unsaturated acid, esters, acrylamide, an initiator and deionized water in a mass ratio of (100-200):(40-80):(20-40):(20-40):(1-5):(500-750) into a No.2 reaction kettle, heating to 85-90 DEG C, stirring the mixture to react for 4 hours, cooling a reaction product to room temperature, and regulating the pH value to be about 7 by using liquid caustic soda to obtain the modified malt syrup retarder.

The invention discloses delayed coagulation cement paste for freezing shaft sinking construction and belongs to the technical field of slurry. The cement slurry comprises the following components in parts by weight: 190-210 parts of cement, 780-820 parts of fly ash, 970-1030 parts of water, 180-200 parts of glycerol and 1.3-4 parts of sulfonated lignite resin. On the premise that the final settingstrength of the cement paste reaches 10 MPa, the cement paste can be set slowly for 45 hours at the high temperature of 40 DEG C, and meanwhile, the cement paste has high flowability and low water loss.

The invention discloses a modified cassava starch-polycarboxylic acid composite water reducing agent, and belongs to the field of building materials. The modified cassava starch-polycarboxylic acid composite water reducing agent is prepared from the following raw materials in parts by weight: 20 to 35 parts of modified cassava starch, 30 to 120 parts of sodium hydroxide, 2 to 6 parts of retarder,0.5 to 4 parts of defoaming agent and 1 to 5.5 parts of air entraining agent. The content of the modified cassava starch in the composite water reducing agent reaches 20% or above, and when the mixingamount of the water reducing agent is 0.3%, the coagulation time exceeds 24 h, and the requirement of the super retarder is met; and when the mixing amount of the composite water reducing agent is 1%, the initial fluidity of the cement paste is greater than 200mm. The development and application of the cassava starch water reducing agent are beneficial to improving the processing technology of the water reducing agent, improving the product quality of the water reducing agent and reducing the environmental pollution, and can effectively solve the problem of output of Guangxi agricultural products and improve the additional value of the products.

The invention discloses a preparation method of a retarder applied to preparation of a modified cassava starch-polycarboxylic acid composite water reducing agent, and belongs to the field of buildingmaterials. The preparation method of the retarder comprises the following steps: uniformly mixing sodium gluconate, sodium citrate, sodium tripolyphosphate, sodium pyrophosphate, ammonium borate and water, adjusting the pH value of the solution to 5.5-6.5, adding magnesium sulfate, introducing nitrogen, and adding ferrous sulfate at 60 DEG C for free radical polymerization; observing the reactiontemperature, starting timing when the temperature is the highest, and obtaining the retarder after 2 hours. The composite water reducing agent containing the retarder prepared by adopting the processdisclosed by the invention can adjust the setting time of concrete and improve the performance of the concrete, and also has the effects of specifically improving the net slurry fluidity of the concrete, reducing the construction energy consumption and the like.

The invention discloses a preparation method of an air entraining agent applied to preparation of a modified cassava starch-polycarboxylic acid composite water reducing agent, and belongs to the fieldof building materials. The preparation method of the air entraining agent comprises the following steps: putting rosin powder, p-toluenesulfonic acid and sodium hydroxide into a reaction kettle, adding water accounting for 50% of the total mass of the mixture A, mixing and stirring for 30 minutes, heating to 80 DEG C, keeping the temperature for 50 minutes, heating to 80 DEG C, and keeping the temperature for 45 minutes; heating the mixed solution A to 85 DEG C, slowly adding pentaerythritol and tall oil, keeping the temperature for 35 minutes, heating to 70-85 DEG C, slowly adding mahogany petroleum sulfonate, and keeping the temperature for 1 hour to obtain the air entraining agent. The air entraining agent has a good air entraining effect, the average pore diameter of air entraining bubbles is small, the durability of concrete is remarkably improved, meanwhile, the workability of the concrete is obviously improved, the slump loss of the concrete is reduced, and the strength of theconcrete is not reduced.

The invention relates to a material for buildings, and in particular to a preparation method for a thermal insulation type gypsum board. The preparation method utilizes fermented oxytetracycline fungus residue as a raw material to prepare an additive for the preparation process of phosphogypsum. Fermentation is firstly carried out, the cooperation between microwave heating and basic hydrolysis isthen utilized, so that the hydrolysis reaction of the fungus residue is intensified, consequently, the time of hydrolysis is greatly shortened, and the efficiency of the hydrolysis reaction is effectively improved. Fungus residue protein belongs to single-cell protein, and the molecular weight is lower. The content of free amino acid in a set retarder is higher, a small amount of small peptide substance is also contained, main chelating functional groups which are produced by the set retarder and calcium ions are the amino group and the carboxyl group, calcium chelate colloid can be adsorbed onto the surfaces of gypsum crystal nucleus, consequently, the axial growth of the crystal nucleus is inhibited, the morphology of gypsum is changed, the crystallization speed of the gypsum is retarded, and thereby the time of gypsum setting retardation is prolonged.

The invention aims to provide special ultrathin-layer masonry mortar for sintered building blocks made of regenerated fine powder containing red bricks. The special ultrathin-layer masonry mortar comprises the following components in parts by weight: 250-430 parts of cement, 195-375 parts of regenerated fine powder containing red bricks, 300-525 parts of fine sand, 6-10 parts of redispersible latex powder, 1.5-2 parts of hydroxypropyl methyl cellulose ether, 0.2-1.05 parts of water reducing agent and 0.3-0.5 part of wood fiber. According to the ultrathin-layer masonry mortar, all components utilize red brick-containing recycled fine powder, sorting and powder removal are not needed in the processing process of red brick-containing construction waste, the production process is low-carbon and environment-friendly, the cost is low, and the utilization problem of the sand powder mixture which is most difficult to utilize in the construction waste recycling process is successfully solved. The regenerated fine powder is adopted to partially replace natural fine sand, the mortar joint thickness of the obtained ultrathin-layer masonry mortar is not larger than 2 mm, and the ultrathin-layermasonry mortar has the advantages of being high in activity, high in water-retaining property, good in construction performance, capable of insulating heat and saving energy, environmentally friendlyand the like.

The invention discloses a defoaming agent and application thereof in preparation of a modified cassava starch-polycarboxylic acid composite water reducing agent, and belongs to the field of building materials. The defoaming agent is prepared from the following components in parts by weight: 30 to 65 parts of hydrogen silicone oil, 20 to 40 parts of high-carbon alcohol fatty acid ester compound, 10to 17 parts of polyoxyethylene polyoxypropylene pentaerythritol ether, 10 to 15 parts of octamethylcyclotetrasiloxane, 5 to 9 parts of polyether silicone oil and 3 to 6 parts of polyoxypropylene polyoxyethylene glyceryl ether. The cassava starch is subjected to oxidation, acidification, etherification, grafting, neutralization and other reaction processes to prepare the starch-containing composite water reducing agent. The strength of concrete is reduced by harmful bubbles generated in the concrete, and the quality of the concrete is influenced; the defoaming agent is good in defoaming effect, the harmful bubbles in the concrete can be efficiently eliminated, and air holes influencing the performance are prevented from being formed. When the mixing amount of the water reducing agent is 1%, the initial fluidity of cement paste is larger than 200 mm, and the water reducing agent has a good water reducing effect.