CN108329435B - Method for preparing polycarboxylic acid water reducing agent - Google Patents
Method for preparing polycarboxylic acid water reducing agent Download PDFInfo
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- CN108329435B CN108329435B CN201810157121.5A CN201810157121A CN108329435B CN 108329435 B CN108329435 B CN 108329435B CN 201810157121 A CN201810157121 A CN 201810157121A CN 108329435 B CN108329435 B CN 108329435B
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- water reducing
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- reducing agent
- polycarboxylic acid
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F283/00—Macromolecular compounds obtained by polymerising monomers on to polymers provided for in subclass C08G
- C08F283/06—Macromolecular compounds obtained by polymerising monomers on to polymers provided for in subclass C08G on to polyethers, polyoxymethylenes or polyacetals
- C08F283/065—Macromolecular compounds obtained by polymerising monomers on to polymers provided for in subclass C08G on to polyethers, polyoxymethylenes or polyacetals on to unsaturated polyethers, polyoxymethylenes or polyacetals
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B24/00—Use of organic materials as active ingredients for mortars, concrete or artificial stone, e.g. plasticisers
- C04B24/16—Sulfur-containing compounds
- C04B24/161—Macromolecular compounds comprising sulfonate or sulfate groups
- C04B24/163—Macromolecular compounds comprising sulfonate or sulfate groups obtained by reactions only involving carbon-to-carbon unsaturated bonds
- C04B24/165—Macromolecular compounds comprising sulfonate or sulfate groups obtained by reactions only involving carbon-to-carbon unsaturated bonds containing polyether side chains
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B24/00—Use of organic materials as active ingredients for mortars, concrete or artificial stone, e.g. plasticisers
- C04B24/24—Macromolecular compounds
- C04B24/26—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
- C04B24/2605—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds containing polyether side chains
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2103/00—Function or property of ingredients for mortars, concrete or artificial stone
- C04B2103/30—Water reducers, plasticisers, air-entrainers, flow improvers
- C04B2103/302—Water reducers
Abstract
The invention discloses a method for synthesizing a polycarboxylic acid high-performance water reducing agent, and belongs to the field of cement concrete water reducing agents. The invention mixes unsaturated polyoxyethylene ether or unsaturated polyester macromonomer, unsaturated carboxylic acid or unsaturated anhydride small monomer, chain transfer agent and initiator, and then carries out mechanical ball milling to cause the mixture to generate mechanochemical reaction, and then removes the obtained product, adds water to dissolve the product, and uses alkaline liquor to adjustpHAnd obtaining the polycarboxylic acid high-performance water reducing agent with the value of 6-8. The preparation method disclosed by the invention is simple in preparation process, short in time, low in cost, high in product solid content, capable of greatly reducing energy consumption and convenient to transport and use, and the prepared polycarboxylic acid high-performance water reducing agent has the characteristics of high water reducing rate and good slump retaining performance and is suitable for industrial large-scale production.
Description
Technical Field
The invention belongs to the technical field of concrete admixtures, and relates to a preparation method of a water reducing agent, in particular to a method for preparing a polycarboxylic acid water reducing agent.
Background
The polycarboxylate water reducing agent (PCE) is a known concrete additive, is mainly used in concrete mixtures, is a third-generation high-performance concrete water reducing agent after a lignin sulfonate water reducing agent and a naphthalene water reducing agent, and has received wide attention of researchers at home and abroad. The polycarboxylic acid water reducing agent (PCE) is a concrete admixture which is researched and applied most widely at present, can greatly reduce the using amount of mixing water, improve the construction performance of concrete and improve the strength and durability of hardened concrete under the condition of keeping the workability of premixed concrete unchanged, and has the advantages of low mixing amount, strong adaptability of cementing materials, low loss rate, environment-friendly preparation process and the like. The polycarboxylic acid water reducing agent is widely applied and develops rapidly. In Japan, the PCE product accounts for 90 percent of the total amount of the water reducing agent product, the yield of the polycarboxylic acid water reducing agent in 2015 in China reaches over 620 ten thousand tons (calculated according to the concentration of 20 percent), and the PCE product accounts for 72.9 percent of the total amount of the total synthesized water reducing agent, which is 124 times of that in 2005.
The polycarboxylic acid water reducing agent is obtained by mainly copolymerizing unsaturated monomers under the action of an initiator and grafting active groups with side chains onto a polymer main chain, and belongs to free radical copolymerization reaction. At present, the polymerization process used is solution polymerization, which is subdivided into three specific processes: copolymerization of active monomers, functionalization after polymerization and in-situ polymerization and grafting. The general polycarboxylic acid water reducing agent is prepared by a solution polymerization method, the reaction time is more than 3 hours, and certain heating is needed, so that the obtained polycarboxylic acid water reducing agent product is usually in a liquid state, has low solid content and large volume, and is inconvenient to store and transport. Chinese patent CN106188422A synthesizes a solid polycarboxylic acid water reducing agent by an organic solvent system, and adds unsaturated carboxylic acid, unsaturated alcohol polyether and toluene; and adding mercaptoacetic acid and azobisisobutyronitrile, performing free radical copolymerization under the condition of mechanical stirring, decompressing and evaporating toluene after the reaction is finished, and mechanically crushing to obtain the solid polycarboxylic acid water reducing agent.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide a method for preparing a polycarboxylic acid water reducing agent. The method for synthesizing the polycarboxylic acid water reducer by mechanical ball milling has the advantages of no need of heating, short synthesis reaction time within 30 minutes, simple process, less time consumption, no addition of organic solvent, low cost, high yield of the obtained polycarboxylic acid water reducer, and convenience in storage and transportation.
The invention provides a method for preparing a polycarboxylic acid water reducing agent, which comprises the following specific steps:
the first step is as follows: mixing a large monomer, a small monomer, a chain transfer agent and an initiator, wherein the large monomer is selected from unsaturated polyoxyethylene ether or unsaturated polyester, and the small monomer is selected from unsaturated carboxylic acid or unsaturated anhydride, and then mechanically ball-milling the mixed solution in a ball mill for 5-30 min to perform mechanochemical reaction;
specifically, the unsaturated polyoxyethylene ether is preferably one or a mixture of more of isopentenyl polyoxyethylene ether, allyl polyoxyethylene ether and methallyl polyoxyethylene ether.
The unsaturated polyester macromonomer is preferably one or a mixture of more of methoxy polyethylene glycol acrylate, methoxy polyethylene glycol methacrylate and methoxy polyethylene glycol maleate.
The unsaturated carboxylic acid monomer is preferably one or a mixture of acrylic acid, methacrylic acid, itaconic acid, citraconic acid or fumaric acid.
The unsaturated anhydride is selected from maleic anhydride.
The chain transfer agent is preferably one or a mixture of more of sodium methallyl sulfonate, mercaptopropionic acid and thioglycolic acid.
The initiator is preferably one or a mixture of ammonium persulfate, potassium persulfate and ascorbic acid-hydrogen peroxide.
Further, the preferable weight average molecular weight of the unsaturated polyoxyethylene ether or unsaturated polyester macromonomer is 400 to 2400.
Further, the molar ratio of the unsaturated polyoxyethylene ether or unsaturated polyester macromonomer, the unsaturated carboxylic acid or unsaturated anhydride monomer and the chain transfer agent is 1.0: 1.0-8.0: 0.05-3.0.
Furthermore, the dosage of the initiator is 1.0-2.0% of the mass of the unsaturated alcohol polyether.
Further, the above-mentioned mechanical ball milling reaction may be carried out in a planetary, drum, stirring or vibrating ball mill.
Second oneThe method comprises the following steps: after the mechanochemical reaction is finished, the obtained product is removed, dissolved in deionized water and adjusted by alkali liquorpHTo finally obtainpHThe value of the polycarboxylic acid high-performance water reducing agent is 6-8.
Specifically, the alkali liquor is selected from one or a mixture of sodium hydroxide, potassium hydroxide and calcium hydroxide.
The preparation method of the polycarboxylic acid high-performance water reducing agent has the advantages of simple process, no need of heating for reaction, short time, low cost, high solid content of the product, capability of greatly reducing energy consumption, convenience in transportation and use, and high water reducing rate and good slump retaining performance. Compared with the existing preparation method, the preparation method has obvious characteristics and substantial progress, thereby having good application prospect.
Detailed Description
The invention is further illustrated and described below with reference to specific embodiments, but the invention is not limited in any way.
The method for preparing the polycarboxylic acid high-performance water reducing agent comprises the following steps:
1) unsaturated polyoxyethylene ether or unsaturated polyester macromonomer, unsaturated carboxylic acid such as acrylic acid, chain transfer agent such as sodium methallyl sulfonate and initiator are mixed and then mechanically ball-milled in a ball mill without heating so as to cause the mechanical chemical reaction.
2) Removing the product obtained in the step 1), dissolving with deionized water, and adjusting the solution with alkali liquorpHTo make itpH6-8, thus obtaining the polycarboxylic acid high-performance water reducing agent.
The steps in the method for producing the water-reducing agent described below are conventional methods unless otherwise specified, and the raw materials are commercially available from public sources unless otherwise specified.
Example one
Isopentenyl polyoxyethylene ether with molecular weight of 2400: acrylic acid: weighing sodium methallyl sulfonate with the molar ratio of 1.0:2.5:0.08, weighing ammonium persulfate with the amount of 1.0 percent of the mass of the isopentenyl polyoxyethylene ether, and placing the ammonium persulfate into a beaker to be uniformly stirred. Mixing the monomersAdding the materials into a ball milling tank, screwing the ball milling tank, installing the ball milling tank on a planetary ball mill, setting the ball milling time for 30min, and starting the ball milling reaction. Taking out the reaction product after the reaction is finished, dissolving the reaction product with water, and regulating the reaction product by using 30 percent sodium hydroxide solutionpHAnd = 6-8, and the record of the finally obtained polycarboxylic acid high-performance water reducing agent is PC-1.
Example two
Allyl polyoxyethylene ether with molecular weight of 400: methacrylic acid: weighing mercaptopropionic acid with the molar ratio of 1.0:1.0:0.05, weighing potassium persulfate with the amount of 1.5 percent of the mass of the allyl polyoxyethylene ether, and placing the potassium persulfate in a beaker to stir uniformly. Adding the monomer mixture into a ball milling tank, screwing the ball milling tank, installing the ball milling tank on a roller ball mill, setting the ball milling time for 25min, and starting the ball milling reaction. Taking out the reaction product after the reaction is finished, dissolving the reaction product with water, and regulating the reaction product by using 30 percent potassium hydroxide solutionpHAnd = 6-8, and the record of the finally obtained polycarboxylic acid high-performance water reducing agent is PC-2.
EXAMPLE III
According to the molecular weight of 1200 methyl allyl polyoxyethylene ether: itaconic acid: weighing sodium methallyl sulfonate with the molar ratio of 1.0:3.5:0.5, weighing ammonium persulfate with the amount of 2.0 percent of the mass of the methallyl polyoxyethylene ether, and placing the ammonium persulfate into a beaker for uniformly stirring. Adding the monomer mixture into a ball milling tank, screwing the ball milling tank, installing the ball milling tank on a stirring type ball mill, setting the ball milling time for 20min, and starting the ball milling reaction. Taking out the reaction product after the reaction is finished, dissolving the reaction product with water, and regulating the reaction product by using 30 percent calcium hydroxide solutionpHAnd = 6-8, and the record of the finally obtained polycarboxylic acid high-performance water reducing agent is PC-3.
Example four
Methoxypolyethylene glycol acrylate with molecular weight of 1000: citraconic acid: weighing thioglycollic acid with the molar ratio of 1.0:4.5:1.0, weighing ascorbic acid-hydrogen peroxide with the amount of 2.0% of the mass of the methoxypolyethylene glycol acrylate, and uniformly stirring in a beaker. Adding the monomer mixture into a ball milling tank, screwing the ball milling tank, installing the ball milling tank on a vibration type ball mill, setting the ball milling time for 15min, and starting the ball milling reaction. Taking out the reaction product after the reaction is finished, dissolving the reaction product with water, and regulating the reaction product by using 30 percent sodium hydroxide solutionpH= 6-8, and the record of the polycarboxylic acid high-performance water reducing agent finally obtained isPC-4。
EXAMPLE five
According to the molecular weight of 1500, the method comprises the following steps: fumaric acid: weighing sodium methallyl sulfonate with the molar ratio of 1.0:6.0:1.5, weighing ammonium persulfate with the amount of 1.0 percent of the mass of the methoxypolyethylene glycol methacrylate, and placing the mixture into a beaker for uniformly stirring. Adding the monomer mixture into a ball milling tank, screwing the ball milling tank, installing the ball milling tank on a planetary ball mill, setting the ball milling time for 10min, and starting the ball milling reaction. Taking out the reaction product after the reaction is finished, dissolving the reaction product with water, and regulating the reaction product by using 30 percent sodium hydroxide solutionpHAnd = 6-8, and the record of the finally obtained polycarboxylic acid high-performance water reducing agent is PC-5.
EXAMPLE six
According to a molecular weight of 2000 methoxy polyethylene glycol maleate: maleic anhydride: weighing sodium methallyl sulfonate with the molar ratio of 1.0:8:3.0, weighing ammonium persulfate with the amount of 2.0 percent of the mass of the methoxypolyethylene glycol maleate, and uniformly stirring in a beaker. Adding the monomer mixture into a ball milling tank, screwing the ball milling tank, installing the ball milling tank on a stirring type ball mill, setting the ball milling time for 5min, and starting the ball milling reaction. Taking out the reaction product after the reaction is finished, dissolving the reaction product with water, and regulating the reaction product by using 30 percent sodium hydroxide solutionpHAnd = 6-8, and the record of the finally obtained polycarboxylic acid high-performance water reducing agent is PC-6.
Comparative example
Isopentenyl polyoxyethylene ether with molecular weight of 2400: acrylic acid: the molar ratio of the sodium methallyl sulfonate is 1.0:2, the monomers are weighed, and the using amount of the ammonium persulfate is weighed to be 1.0 percent of the mass of the isopentenyl polyoxyethylene ether. Dissolving isopentene polyoxyethylene ether in a four-neck flask with a condenser tube by using a certain amount of water. Meanwhile, an initiator solution A (ammonium persulfate + water) and a monomer mixed solution B (acrylic acid + sodium methallyl sulfonate + water) are prepared. Heating the macromonomer to 60 ℃, dripping A, B two monomers, and finishing dripping within about 70 min. Heating to 75 ℃, and reacting for 3 hours under the condition of heat preservation. After the reaction is finished, the temperature is reduced to room temperature and adjusted by 30 percent sodium hydroxidepHAnd = 6-8, obtaining the polycarboxylate superplasticizer PC-7.
The water reducing agents obtained in the above examples and comparative examples were tested and the results are detailed in table 1.
The test measures the net slurry fluidity of each example and each comparative example at the same mixing amount. The test is carried out according to GB/T8077-2000 'homogeneity test method for concrete admixtures', wherein W/C is 0.29, and the mixing amount is the bending and fixing mixing amount. The test results are shown in table 1:
table 1: net slurry flow performance results
As can be seen from the specific results in Table 1 above, the solid content of the polycarboxylic acid water reducer synthesized by the mechanochemical method of the present invention is significantly higher than that of the polycarboxylic acid water reducer prepared by the prior art, the reaction time is significantly shorter than that of the polycarboxylic acid water reducer prepared by the prior art, and the net slurry fluidity and fluidity retention reach those of the polycarboxylic acid water reducer prepared by the prior art, which proves that the polycarboxylic acid water reducer of the present invention has very good practical value.
The preparation method of the polycarboxylic acid water reducer has the advantages of simple process, energy consumption reduction, no addition of organic solvent, low cost, high yield of the obtained polycarboxylic acid water reducer, and easiness in storage and transportation of products.
Having described embodiments of the present invention, the foregoing description is intended to be exemplary, not exhaustive, and not limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (6)
1. A method for preparing a polycarboxylic acid water reducing agent comprises the following steps:
the first step is as follows: mixing a large monomer, a small monomer, a chain transfer agent and an initiator, and carrying out mechanical ball milling in a ball mill for 5.0-30.0 minutes, wherein the large monomer is unsaturated polyoxyethylene ether or unsaturated polyester, the weight average molecular weight of the unsaturated polyoxyethylene ether or unsaturated polyester is 400-2400, and the small monomer is unsaturated carboxylic acid or unsaturated anhydride;
the second step is that: after the reaction is finished, the obtained product is removed, dissolved by adding water and adjusted by alkali liquorpHAnd obtaining the polycarboxylic acid high-performance water reducing agent with the value of 6-8.
2. The method of claim 1, wherein in the first step:
the unsaturated polyoxyethylene ether is selected from one or a mixture of isopentenyl polyoxyethylene ether, allyl polyoxyethylene ether or methyl allyl polyoxyethylene ether;
the unsaturated polyester is selected from one or a mixture of more of methoxy polyethylene glycol acrylate, methoxy polyethylene glycol methacrylate or methoxy polyethylene glycol maleate;
the unsaturated carboxylic acid is selected from one or a mixture of acrylic acid, methacrylic acid, itaconic acid, citraconic acid and fumaric acid;
the unsaturated anhydride is selected from maleic anhydride;
the chain transfer agent is selected from one or a mixture of more of sodium methyl propylene sulfonate, mercaptopropionic acid and thioglycolic acid;
the initiator is selected from one or a mixture of more of ammonium persulfate, potassium persulfate and ascorbic acid-hydrogen peroxide.
3. The method of claim 1 or 2, wherein the molar ratio of the macromonomer to the small monomer to the chain transfer agent used in the first step is 1.0:1 to 8.0:0.05 to 3.0.
4. The process according to claim 1 or 2, wherein the amount of the initiator used in the first step is 1.0 to 2.0% by mass of the macromonomer.
5. The method according to claim 1, wherein the mechanical ball milling reaction in the first step is carried out in a planetary, drum, stirring, or vibrating ball mill.
6. The method according to claim 1, wherein the alkali solution in the second step is selected from one or more of sodium hydroxide, potassium hydroxide and calcium hydroxide.
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| CN112029049A (en) * | 2020-09-14 | 2020-12-04 | 安徽瑞和新材料有限公司 | Solvent-free low-temperature ball milling preparation method of solid polycarboxylic slump retaining agent |
| CN112645630B (en) * | 2020-12-19 | 2023-02-10 | 厦门宏发先科新型建材有限公司 | Fluorine-containing early-strength polycarboxylate superplasticizer, preparation method thereof and early-strength concrete |
| CN112679674A (en) * | 2020-12-29 | 2021-04-20 | 江西富创新材料有限公司 | Polycarboxylate superplasticizer and production process thereof |
| CN113278144B (en) * | 2021-05-12 | 2022-06-07 | 北京金隅水泥节能科技有限公司 | Viscosity-reducing polycarboxylic acid water reducer and preparation method thereof |
| CN113912842B (en) * | 2021-09-14 | 2023-10-24 | 科之杰新材料集团有限公司 | Ligand, conductive early-strength polycarboxylate superplasticizer, conductive early-strength graphene dispersion slurry and preparation method thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN103554382A (en) * | 2013-09-25 | 2014-02-05 | 沈阳建筑大学 | Method for solid-phase synthesizing polycarboxylic acid water reducer |
| CN107698716A (en) * | 2017-07-06 | 2018-02-16 | 徐州巨龙新材料科技有限公司 | A kind of polycarboxylate water-reducer and preparation method thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN103554382A (en) * | 2013-09-25 | 2014-02-05 | 沈阳建筑大学 | Method for solid-phase synthesizing polycarboxylic acid water reducer |
| CN107698716A (en) * | 2017-07-06 | 2018-02-16 | 徐州巨龙新材料科技有限公司 | A kind of polycarboxylate water-reducer and preparation method thereof |
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