CN114479057A - Ester monomer, polycarboxylate superplasticizer and preparation method thereof - Google Patents

Ester monomer, polycarboxylate superplasticizer and preparation method thereof Download PDF

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CN114479057A
CN114479057A CN202111618940.3A CN202111618940A CN114479057A CN 114479057 A CN114479057 A CN 114479057A CN 202111618940 A CN202111618940 A CN 202111618940A CN 114479057 A CN114479057 A CN 114479057A
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monomer
acid
ester
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unsaturated acid
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CN114479057B (en
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李格丽
邵幼哲
吴传灯
林志群
方云辉
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Kezhijie New Material Group Co Ltd
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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G65/00—Macromolecular compounds obtained by reactions forming an ether link in the main chain of the macromolecule
    • C08G65/02—Macromolecular compounds obtained by reactions forming an ether link in the main chain of the macromolecule from cyclic ethers by opening of the heterocyclic ring
    • C08G65/32—Polymers modified by chemical after-treatment
    • C08G65/329—Polymers modified by chemical after-treatment with organic compounds
    • C08G65/331—Polymers modified by chemical after-treatment with organic compounds containing oxygen
    • C08G65/332—Polymers modified by chemical after-treatment with organic compounds containing oxygen containing carboxyl groups, or halides, or esters thereof
    • C08G65/3322—Polymers modified by chemical after-treatment with organic compounds containing oxygen containing carboxyl groups, or halides, or esters thereof acyclic
    • 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
    • C04B24/2688—Copolymers containing at least three different monomers
    • C04B24/2694—Copolymers containing at least three different monomers containing polyether side chains
    • 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
    • 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
    • C08F290/00—Macromolecular compounds obtained by polymerising monomers on to polymers modified by introduction of aliphatic unsaturated end or side groups
    • C08F290/02—Macromolecular compounds obtained by polymerising monomers on to polymers modified by introduction of aliphatic unsaturated end or side groups on to polymers modified by introduction of unsaturated end groups
    • C08F290/06—Polymers provided for in subclass C08G
    • C08F290/062—Polyethers
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G65/00—Macromolecular compounds obtained by reactions forming an ether link in the main chain of the macromolecule
    • C08G65/02—Macromolecular compounds obtained by reactions forming an ether link in the main chain of the macromolecule from cyclic ethers by opening of the heterocyclic ring
    • C08G65/26—Macromolecular compounds obtained by reactions forming an ether link in the main chain of the macromolecule from cyclic ethers by opening of the heterocyclic ring from cyclic ethers and other compounds
    • C08G65/2603—Macromolecular compounds obtained by reactions forming an ether link in the main chain of the macromolecule from cyclic ethers by opening of the heterocyclic ring from cyclic ethers and other compounds the other compounds containing oxygen
    • C08G65/2606—Macromolecular compounds obtained by reactions forming an ether link in the main chain of the macromolecule from cyclic ethers by opening of the heterocyclic ring from cyclic ethers and other compounds the other compounds containing oxygen containing hydroxyl groups
    • C08G65/2609—Macromolecular compounds obtained by reactions forming an ether link in the main chain of the macromolecule from cyclic ethers by opening of the heterocyclic ring from cyclic ethers and other compounds the other compounds containing oxygen containing hydroxyl groups containing aliphatic hydroxyl groups
    • 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
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W30/00—Technologies for solid waste management
    • Y02W30/50—Reuse, recycling or recovery technologies
    • Y02W30/91—Use of waste materials as fillers for mortars or concrete

Abstract

The invention relates to the field of concrete admixtures, and provides an ester monomer, a polycarboxylic acid water reducing agent and a preparation method thereof. The ester monomer is generated by the reaction of reactants including polyalcohol, epoxy monomer and unsaturated acid, wherein the epoxy monomer is one of ethylene oxide, epichlorohydrin, propylene oxide or epoxy hexane, and the unsaturated acid is acrylic acid or methacrylic acid. The polycarboxylate superplasticizer is prepared by free radical polymerization of ester monomers, polyether monomers, unsaturated acid and double-bond-containing hydroxy carboxylic ester, wherein the ester monomers: polyether monomer: unsaturated acid: the mass ratio of the double-bond-containing hydroxycarboxylic acid ester is 1-5: 150-200: 10-30: 1-5. The polycarboxylate superplasticizer prepared by the invention adopts the copolyester monomer to introduce ester group, so that the carboxyl content is not reduced due to esterification, and the polycarboxylate superplasticizer has the advantages of good polymerization activity, excellent water reducing and slump retaining effects, low biological toxicity and good environmental protection.

Description

Ester monomer, polycarboxylate superplasticizer and preparation method thereof
Technical Field
The invention relates to the field of concrete admixtures, in particular to an ester monomer, a polycarboxylic acid water reducing agent and a preparation method thereof.
Background
The ester polycarboxylate superplasticizer has the advantages of high water reducing rate, good universality with aggregate, higher workability, lower sensitivity and the like, and is widely applied to domestic and foreign markets in recent years. Common ester synthesis methods include solid acid catalysis, ester exchange, phase transfer catalysis, microwave synthesis, and the like. In the production of the ester polycarboxylic acid water reducing agent, the common ester exchange method generally comprises two steps, firstly, a polymerization monomer with molecular activity is prepared by adopting an indirect or indirect esterification method, and then the prepared polymerization monomer is used as a raw material to be polymerized by a copolymerization method to synthesize the polyester polycarboxylic acid water reducing agent with different types or different performances.
At present, an ester polycarboxylate water reducer is generally prepared by esterifying two unsaturated acids, namely acrylic acid or methacrylic acid, and polyethylene glycol monomethyl ether to synthesize a macromolecular monomer, and copolymerizing the macromolecular monomer and other micromolecular monomers containing active groups, but after esterification, the carboxyl content of the macromolecular monomer disappears or is reduced, so that the performance of the prepared polycarboxylate water reducer is influenced. Other substances are adopted to replace acrylic acid for esterification, but due to poor polymerization activity of the selected substitute, the polymerization activity of the prepared macromonomer is influenced, the polymerization activity of the next step is influenced, and finally the performance of the prepared polycarboxylic acid water reducer is influenced.
Chinese patent with publication number CN109369860A published in 2, month and 22 of 2019 discloses a sustained-release controllable polycarboxylate superplasticizer mother liquor and a preparation method thereof, wherein a macromonomer TPEG, a monoester small monomer, a diester small monomer and a functional monomer are used as polymerization monomers, and the pH value of a polycarboxylate superplasticizer polymer is adjusted to be strong alkaline for partial hydrolysis, so that the sustained release controllability of the polycarboxylate superplasticizer mother liquor is realized. However, the adopted diester small monomers do not contain hydroxyl components and have limited ester group content, and the adopted monoester small monomers have insufficient active density, so that the slump retaining performance of the mother liquor of the polycarboxylate superplasticizer is limited.
Disclosure of Invention
In order to solve the problem that the slump retaining performance of the polycarboxylate water reducer in the prior art is limited, the invention provides an ester monomer, which is generated by reacting reactants including polyol, epoxy monomer and unsaturated acid, wherein the epoxy monomer is one of ethylene oxide, epichlorohydrin, propylene oxide or epoxy hexane, the unsaturated acid is acrylic acid or methacrylic acid, and the polyol: epoxy monomer: the mass ratio of the unsaturated acid is 3-5: 6-10: 9-15.
In one embodiment, the polyol is 3 to 5 parts, the epoxy monomer is 6 to 10 parts, and the unsaturated acid is 9 to 15 parts.
In one embodiment, the polyol is one of ethylene glycol, glycerol, trihydroxypropane, glucose, and sorbitol.
In one embodiment, the molecular weight of the ester monomer is 1000 to 3000.
In one embodiment, the ester monomer is formed by polymerizing the polyol and the epoxy monomer and esterifying with the unsaturated acid.
The invention also provides a preparation method of the ester monomer as claimed in the claim, which comprises the following specific steps: weighing a catalyst and the unsaturated acid to prepare a solution A; weighing the polyol, the epoxy monomer and the polymerization inhibitor, uniformly stirring, and keeping the temperature at T1The solution A is added dropwise at the beginning, and the adding time is t1After the addition is finished, at T2Constant temperature t at temperature2And cooling to room temperature until the acid value is M.
In one embodiment, the room temperature is 25 ℃ to 28 ℃.
In a preferred embodiment, the room temperature is 25 ℃.
In an embodiment of the preparation process, T1Is 80 to 120 ℃ and T2At 80 to 120 ℃ t1Is 1-2 h, t2Is 3 to 5 hours, M is 6 to 10mg KOH/g, T1And T2The temperature can be the same or different.
In one embodiment of the preparation method, the polyol is 3-5 parts, the epoxy monomer is 6-10 parts, the unsaturated acid is 9-15 parts, the catalyst is 1-3 parts, and the polymerization inhibitor is 1-2 parts.
In an embodiment of the preparation method, the polymerization inhibitor is one of hydroquinone, p-hydroxyanisole and tetramethylpiperidine nitroxide.
In one embodiment of the preparation method, the catalyst is one or two of N, N-dimethylaniline, tetraethylammonium bromide, dimethyl diamide, boron trichloride diethyl ether-tin tetrachloride.
The invention also provides a polycarboxylate superplasticizer which is prepared by free radical polymerization of the ester monomer, the polyether monomer, the unsaturated acid and the double-bond-containing hydroxy carboxylic ester in the technical scheme, wherein the ester monomer: the polyether monomer: the unsaturated acid: the mass ratio of the double-bond-containing hydroxycarboxylic ester is 1-5: 150-200: 10-30: 1-5.
In one embodiment, the polyether monomer is 150 to 200 parts, the ester monomer is 1 to 5 parts, the unsaturated acid is 10 to 30 parts, and the hydroxycarboxylic acid ester is 1 to 5 parts.
In a preferred embodiment, the composition further comprises 1-5 parts of an oxidizing agent, 2-10 parts of a reducing agent, 0.5-2 parts of a chain transfer agent, and 300-350 parts of deionized water.
In one embodiment, the reaction product pH is adjusted using a liquid base.
In a preferred embodiment, the liquid caustic soda is 30 to 32 mass percent.
In one embodiment, the unsaturated acid is methacrylic acid or acrylic acid.
In one embodiment, the polyether monomer is one of methallyl polyoxyethylene ether (HPEG), prenol polyoxyethylene ether (TPEG), or ethylene glycol monovinyl polyethylene glycol ether (EPEG).
In a preferred embodiment, the molecular weight of the polyether monomer is 1200 to 5000.
In one embodiment, the double bond-containing hydroxycarboxylic ester has the structure
Figure BDA0003437256270000041
R1Is C2-4 alkenyl, R2Is an alkyl group having 1 to 6 carbon atoms. The double-bond-containing hydroxycarboxylic acid ester contains active alpha-h, and has higher conversion rate and better performance compared with a polycarboxylic acid water reducing agent adopting common hydroxycarboxylic acid ester.
In a preferred embodiment, the alkenyl group contains only one double bond.
In one embodiment, the room temperature is 25 ℃ to 28 ℃.
In a preferred embodiment, the room temperature is 25 ℃.
The invention also provides a preparation method of the polycarboxylate superplasticizer in the technical scheme, which comprises the following specific steps: dissolving a reducing agent in deionized water to obtain a solution B; dissolving unsaturated acid and the double-bond-containing hydroxycarboxylic ester in deionized water to obtain a solution C; dissolving a chain transfer agent in deionized water to obtain a solution D; mixing the polyether monomer, the ester monomer, the initiator and deionized water, stirring uniformly at room temperature, and then simultaneously dropwise adding B, C and D solution for t3And keeping the temperature t after the dropwise addition4And finally, adjusting the pH value of the reaction product to n to obtain the polycarboxylic acid water reducer.
In one embodiment of the method of preparation, the room temperature is between 25 ℃ and 28 ℃.
In a preferred embodiment of the preparation process, the room temperature is 25 ℃.
In an embodiment of the preparation process, t3Is 2-4 h, t41 to 2 hours, and n is 6.0 to 8.0.
In one embodiment of the preparation method, the polyether monomer is 150 to 200 parts, the ester monomer is 1 to 5 parts, the unsaturated acid is 10 to 30 parts, the hydroxycarboxylic acid ester is 1 to 5 parts, the oxidizing agent is 1 to 5 parts, the reducing agent is 2 to 10 parts, the chain transfer agent is 0.5 to 2 parts, and the deionized water is 300 to 350 parts.
In a more preferred embodiment of the preparation method, 30 to 50 parts of deionized water for dissolving the reducing agent, 10 to 20 parts of deionized water for dissolving the unsaturated acid and the hydroxycarboxylic ester, 30 to 50 parts of deionized water for dissolving the chain transfer agent, and the rest of deionized water is mixed with the polyether monomer, the ester monomer, and the initiator.
In one embodiment of the preparation method, the reducing agent is one of L-ascorbic acid, sodium hypophosphite, and sodium formaldehyde sulfoxylate.
In an embodiment of the method of preparation, the initiator is one of hydrogen peroxide, sodium persulfate, or ammonium persulfate.
In one embodiment of the preparation method, the chain transfer agent is one of thioglycolic acid, mercaptopropionic acid or mercaptoethanol
In one embodiment of the preparation process, the reaction product pH is adjusted using a liquid base.
In a preferred embodiment of the preparation method, the liquid caustic soda is 30-32% by mass.
Based on the above, compared with the prior art, the ester monomer prepared by the invention has higher reaction activity after the hydroxyl groups at two ends of the polyhydric alcohol are esterified and activated, and more active sites can be provided in the synthesis process of the polycarboxylic acid water reducing agent, so that the synthesized polycarboxylic acid water reducing agent has better dispersing performance and working performance. The ester monomer structure contains alkoxy structure units such as ethoxy structure units, propoxy structure units and the like, so that the ester monomer has better water reducing performance and slump retaining performance. The methacrylate double bond of the end group has in-situ crosslinking effect, and the synthesized polycarboxylate superplasticizer has low biological toxicity and good environmental protection property. The alkoxy blocks of ethylene oxide, propylene oxide and the like in the ester monomer can provide the dispersing property for the polycarboxylate water reducer through the steric hindrance effect in the synthesis process of the polycarboxylate water reducer.
According to the ester monomer prepared by the invention, the polyol is adopted to utilize the ring-opening-easy effect of the epoxy monomer, and the hydroxyl and the carboxyl are reacted to generate the ester monomer.
The hydroxycarboxylic acid ester used in the invention contains carbonyl and hydroxyl, has higher polymerization activity, can generate stronger volume steric effect between the carbonyl and the hydroxyl, has higher active density, and can effectively delay the setting time of cement and the like by the water reducing agent which participates in the synthesis, so that the synthesized polycarboxylic acid water reducing agent has better slump retaining performance. In the invention, the environment for synthesizing the polycarboxylate superplasticizer is an acid environment, and the hydroxycarboxylic acid ester hydrolyzes more carboxyl groups than the reaction in an alkaline environment, so the slump loss prevention effect is better.
The polycarboxylate superplasticizer prepared by the invention adopts the copolyester monomer to introduce ester group, so that the carboxyl content is not reduced due to esterification, and the polycarboxylate superplasticizer has the advantages of good polymerization activity, excellent water reducing and slump retaining effects, low biological toxicity and good environmental protection.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are some embodiments of the present invention, but not all embodiments; the technical features designed in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other; all other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In the description of the present invention, it is to be noted that all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs, and are not to be construed as limiting the present invention; it will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
The invention provides the following examples and comparative examples:
example 1
Weighing 3 parts of ethylene glycol, 6 parts of ethylene oxide and 1 part of hydroquinone, putting the mixture into a first reaction device with stirring, condensation and temperature control, and uniformly stirring; 1 part of N, N-dimethylaniline and 9 parts of acrylic acid were weighed into the first addition device. And (3) beginning to dropwise add the first dropwise adding device solution at the temperature of 80 ℃, keeping the temperature of 80 ℃ for 3 hours after dropwise adding is finished, ending when the acid value is 5mg KOH/g, and cooling to room temperature.
2 parts of L-ascorbic acid is dissolved in 30 parts of deionized water and placed in a second dripping device; 10 parts of acrylic acid and 1 part of a double bond-containing hydroxycarboxylic ester (R)1＝2,R22, containing one double bond) was dissolved in 10 parts of deionized water and placed in a third dropping device; 0.5 part of thioglycolic acid is dissolved in 30 parts of deionized water and placed in a fourth dripping device; mixing 150 parts of TPEG-2400, 1 part of ester monomer, 1 part of hydrogen peroxide and 230 parts of deionized water, uniformly stirring, putting into a second reaction device, simultaneously dropwise adding the solution in the second, third and fourth dropwise adding devices for 2 hours, and preserving heat for 1.5 hours after dropwise adding. And after the reaction is finished, adjusting the pH value of the reaction product to 7.0 by using liquid alkali with the mass concentration of 30-32% to obtain the polycarboxylic acid water reducing agent.
Example 2
Weighing 5 parts of glycerol, 10 parts of propylene oxide and 2 parts of p-hydroxyanisole, putting the materials into a first reaction device with stirring, condensation and temperature control, and uniformly stirring; 3 parts tetraethylammonium bromide and 15 parts methacrylic acid were weighed into the first addition device. And (3) beginning to dropwise add the first dropwise adding device solution at the temperature of 100 ℃, keeping the temperature of 100 ℃ for 3.5 hours after dropwise adding is finished, ending until the acid value is 5.5mg KOH/g, and cooling to room temperature.
Dissolving 5 parts of sodium hypophosphite in 40 parts of deionized water, and placing the solution in a second dripping device; 15 parts of methacrylic acid and 2 parts of a double bond-containing hydroxycarboxylic ester (R)1＝3,R24, containing one double bond) was dissolved in 15 parts of deionized water and placed in a third dropping device; dissolving 1 part of mercaptopropionic acid in 40 parts of deionized water, and placing the solution in a fourth dripping device; 160 parts of HPEG-2400, 3 parts of ester monomer, 3 parts of ammonium persulfate and 255 parts of deionized water are mixed together, stirred uniformly, placed into a second reaction device, and simultaneously dropwise added with the solution in the second, third and fourth dropwise adding devices for 3 hours, and then heat preservation is carried out for 2 hours after dropwise addition is finished. And after the reaction is finished, adjusting the pH value of the reaction product to 6.0 by using liquid alkali with the mass concentration of 30-32% to obtain the polycarboxylic acid water reducing agent.
Example 3
Weighing 4 parts of trihydroxy propane, 8 parts of epoxy chloropropane and 2 parts of tetramethyl piperidine nitrogen oxide, putting into a first reaction device with stirring, condensation and temperature control, and uniformly stirring; 1.5 parts of dimethyldiamide and 12 parts of methacrylic acid are weighed into a first addition device. And (3) beginning to dropwise add the first dropwise adding device solution at the temperature of 120 ℃, keeping the temperature of 100 ℃ for 4 hours after dropwise adding is finished, ending when the acid value is 5mg KOH/g, and cooling to room temperature.
Dissolving 8 parts of sodium formaldehyde sulfoxylate in 50 parts of deionized water and placing the solution in a second dripping device; 30 parts of methacrylic acid and 4 parts of a double bond-containing hydroxycarboxylic ester (R)1＝4,R26, containing one double bond) was dissolved in 15 parts of deionized water and placed in a third dropping device; dissolving 1.5 parts of mercaptopropanol in 45 parts of deionized water and placing the solution in a fourth dropping device; 200 parts of EPEG-3600, 4 parts of ester monomer, 2 parts of sodium persulfate and 240 parts of deionized water are mixed together, stirred uniformly, put into a second reaction device, and simultaneously dropwise added with the solution in the second, third and fourth dropwise adding devices for 3.5 hours, and then heat preservation is carried out for 2 hours after dropwise addition. After the reaction is finished, adjusting the pH value of the reaction product to 7.5 by using 30-32% of liquid alkali in mass concentration to obtainThe polycarboxylate superplasticizer is prepared by mixing a polycarboxylic acid water reducer and a water reducer.
Example 4
Weighing 4 parts of sorbitol, 8 parts of epoxy chloropropane and 2 parts of hydroquinone, putting into a first reaction device with stirring, condensation and temperature control, and uniformly stirring; 1.5 parts of boron trichloride diethyl ether-tin tetrachloride and 12 parts of acrylic acid are weighed into a first dripping device. And (3) beginning to dropwise add the first dropwise adding device solution at the temperature of 115 ℃, keeping the temperature of 115 ℃ for 5 hours after dropwise adding is finished, ending until the acid value is 6mg KOH/g, and cooling to room temperature.
Dissolving 10 parts of sodium formaldehyde sulfoxylate in 40 parts of deionized water, and placing the solution in a second dripping device; 15 parts of acrylic acid and 5 parts of a double bond-containing hydroxycarboxylic ester (R)1＝2,R22, containing one double bond) was dissolved in 20 parts of deionized water and placed in a third dropping device; 2 parts of thioglycolic acid is dissolved in 50 parts of deionized water and placed in a fourth dripping device; 200 parts of EPEG-5000, 5 parts of ester monomer, 1.5 parts of ammonium persulfate and 210 parts of deionized water are mixed together, stirred uniformly, placed into a second reaction device, and simultaneously dropwise added with the solution in the second, third and fourth dropwise adding devices for 4 hours, and then heat preservation is carried out for 1.5 hours after dropwise addition. And after the reaction is finished, adjusting the pH value of the reaction product to 8.0 by using liquid alkali with the mass concentration of 30-32% to obtain the polycarboxylic acid water reducing agent.
Comparative example 1
Comparative example 1 differs from example 1 in that polyethylene glycol diacrylate was used instead of the ester monomer of example 1.
Comparative example 2
Comparative example 2 differs from example 1 in that hydroxyethyl acrylate is used instead of the double bond-containing hydroxycarboxylic acid ester of example 1.
Comparative example 3
Comparative example 3 is different from example 1 in that the ester monomer is 6 parts and the water is 295 parts.
Comparative example 4
Comparative example 4 is different from example 1 in that the ester monomer is 0.5 parts and the water is 300.5 parts.
Comparative example 5
Comparative example 5 is different from example 1 in that the double bond-containing hydroxycarboxylic acid ester is 0.5 part and the water is 300.5 parts.
Comparative example 6
Comparative example 6 is different from example 1 in that 6 parts of a double bond-containing hydroxycarboxylic acid ester and 295 parts of water are used.
The grade and other technical indexes of the raw materials adopted in the preparation method, the examples and the comparative examples can be selected according to the prior art, and if the technical indexes are specified in the invention, the technical indexes are selected within the range specified in the invention, so that the technical effect of the invention is not influenced.
The water reducing rate, slump constant and slump loss of concrete over time are measured by adopting standard cement with the mixing amount of 0.20 percent (folded into solid) of the mass of the cement according to GB 8076 plus 2008 concrete admixture. The concrete mixing proportion is as follows: cement 360kg/m3790kg/m of sand3Stone 1060kg/m3The results obtained are shown in Table 1.
TABLE 1
Figure BDA0003437256270000101
In summary, compared with the comparative example, the performance of the example is better than that of the comparative example, in the comparative example 1, the water reducing rate and the slump and the spread of the comparative example 1 at 0h, 1h and 2h are both smaller than those of the example 1, because the polyethylene glycol diacrylate of the comparative example 1 does not contain a polyhydroxy structure, the water reducing performance and the slump retaining performance are reduced; the hydroxyethyl acrylate of the comparative example 2 does not contain alpha hydrogen, the reaction activity is reduced, the conversion rate of the polycarboxylic acid water reducing agent participating in synthesis is reduced, the water reducing performance and the slump retaining performance are reduced, when the ester monomer of the comparative example 3 is excessive, the cement viscosity is too high due to excessive ester groups and hydroxyl groups released, and when the ester monomer of the comparative example 4 is too small, the ester groups and the hydroxyl groups released are insufficient, so that the water reducing performance and the slump retaining performance are reduced; in comparative example 5, too little hydroxycarboxylic acid ester having a double bond releases insufficient ester groups and hydroxyl groups, and in comparative example 6, too much hydroxycarboxylic acid ester having a double bond releases too much ester groups and hydroxyl groups, and the cement viscosity is too high, which all result in a decrease in water-reducing ability and slump-retaining ability.
In conclusion, compared with the prior art, the ester monomer prepared by the invention has higher reaction activity after the hydroxyl groups at two ends of the polyhydric alcohol are esterified and activated, and more active sites can be provided in the synthesis process of the polycarboxylic acid water reducing agent, so that the synthesized polycarboxylic acid water reducing agent has better dispersing performance and working performance. The ester monomer structure contains alkoxy structure units such as ethoxy structure units and propoxy structure units, and the structure units contain polyhydroxy structures, so that the synthesized polycarboxylate superplasticizer has more alkoxy structure units and introduces hydroxyl structures, and has better water reducing performance and slump retaining performance. The methacrylate double bond of the end group has in-situ crosslinking effect, and the synthesized polycarboxylate superplasticizer has low biological toxicity and good environmental protection property. The alkoxy blocks of ethylene oxide, propylene oxide and the like in the ester monomer can provide the dispersing property for the polycarboxylate water reducer through the steric hindrance effect in the synthesis process of the polycarboxylate water reducer.
According to the ester monomer prepared by the invention, the polyol is adopted to utilize the ring-opening-easy effect of the epoxy monomer, and the hydroxyl and the carboxyl are reacted to generate the ester monomer.
The hydroxycarboxylic acid ester used in the invention contains carbonyl and hydroxyl, has higher polymerization activity, can generate stronger volume steric effect between the carbonyl and the hydroxyl, has higher active density, and has higher reaction activity due to the alpha hydrogen, so that the conversion rate of the synthesized polycarboxylic acid water reducing agent is increased, and the synthesized water reducing agent can effectively delay the setting time of cement and the like, so that the synthesized polycarboxylic acid water reducing agent has better slump retaining performance. In the invention, the environment for synthesizing the polycarboxylate superplasticizer is an acid environment, and the hydroxycarboxylic acid ester hydrolyzes more carboxyl groups than the reaction in an alkaline environment, so the slump loss prevention effect is better.
The polycarboxylate superplasticizer prepared by the invention adopts the copolyester monomer to introduce ester group, so that the carboxyl content is not reduced due to esterification, and the polycarboxylate superplasticizer has the advantages of good polymerization activity, excellent water reducing and slump retaining effects, low biological toxicity and good environmental protection.
In addition, it will be appreciated by those skilled in the art that, although there may be many problems with the prior art, each embodiment or aspect of the present invention may be improved only in one or several respects, without necessarily simultaneously solving all the technical problems listed in the prior art or in the background. It will be understood by those skilled in the art that nothing in a claim should be taken as a limitation on that claim.
Although terms such as ester monomers, polyols, epoxy monomers, unsaturated acids, polyether monomers, hydroxy carboxylic acid esters, etc. are used more often herein, the possibility of using other terms is not excluded. These terms are used merely to more conveniently describe and explain the nature of the present invention; they are to be construed as being without limitation to any additional limitations that may be imposed by the spirit of the present invention; the terms "first," "second," and the like in the description and in the claims, if any, of the embodiments of the invention are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims (10)

1. An ester monomer, characterized in that: the epoxy resin is prepared by reacting reactants including polyol, epoxy monomer and unsaturated acid, wherein the epoxy monomer is one of ethylene oxide, epichlorohydrin, propylene oxide or epoxy hexane, the unsaturated acid is acrylic acid or methacrylic acid, and the polyol: epoxy monomer: the mass ratio of the unsaturated acid is 3-5: 6-10: 9-15.
2. The ester monomer of claim 1, wherein: the polyol is one of ethylene glycol, glycerol, trihydroxypropane, glucose and sorbitol, the polyol is 3-5 parts, the epoxy monomer is 6-10 parts, and the unsaturated acid is 9-15 parts.
3. A method for preparing the ester monomer according to claim 1 or 2, wherein: weighing a catalyst and the unsaturated acid to prepare a solution A; weighing the polyol, the epoxy monomer and the polymerization inhibitor, uniformly stirring, and keeping the temperature at T1The solution A is added dropwise at the beginning, and the adding time is t1After the addition is finished, at T2Constant temperature t at temperature2And cooling to room temperature until the acid value is M.
4. The method for preparing an ester monomer according to claim 3, wherein: t is1Is 80 to 120 ℃ and T2At 80 to 120 ℃ t11 to 2 hours, t2The reaction time is 3-5 h, and M is 6-10 mg KOH/g.
5. A polycarboxylate water reducing agent is characterized in that: produced by radical polymerization of an ester monomer according to claim 1 or 2, a polyether monomer, an unsaturated acid and a double bond-containing hydroxycarboxylic ester, the ester monomer: the polyether monomer: the unsaturated acid: the mass ratio of the double-bond-containing hydroxycarboxylic ester is 1-5: 150-200: 10-30: 1-5.
6. The polycarboxylate water reducer of claim 5, characterized in that: the polyether monomer is 150-200 parts, the ester monomer is 1-5 parts, the unsaturated acid is 10-30 parts, and the hydroxycarboxylic acid ester is 1-5 parts.
7. The polycarboxylate water reducer of claim 5, characterized in that: the unsaturated acid is methacrylic acid or acrylic acid, the polyether monomer is one of methyl allyl polyoxyethylene ether, isopentenol polyoxyethylene ether or ethylene glycol monovinyl polyglycol ether, and the molecular weight of the polyether monomer is 1200-5000.
8. The polycarboxylate water reducer of claim 5, characterized in that: the structural formula of the double-bond-containing hydroxycarboxylic ester is as follows:
Figure FDA0003437256260000021
R1is C2-4 alkenyl, R2Is an alkyl group having 1 to 6 carbon atoms.
9. A method for preparing a polycarboxylic acid water reducing agent according to any one of claims 5 to 8, characterized by: dissolving a reducing agent in deionized water to obtain a solution B; dissolving unsaturated acid and the double-bond-containing hydroxycarboxylic ester in deionized water to obtain a solution C; dissolving a chain transfer agent in deionized water to obtain a solution D; mixing the polyether monomer, the ester monomer, the initiator and deionized water, stirring uniformly at room temperature, and then simultaneously dropwise adding B, C and D solution for t3And keeping the temperature t after the dropwise addition4And finally, adjusting the pH value of the reaction product to n to obtain the polycarboxylic acid water reducer.
10. The preparation method of the polycarboxylate water reducer according to claim 9, characterized by comprising the following steps: t is t3Is 2 to 4 hours, t4The reaction time is 1-2 hours, n is 6.0-8.0, the reducing agent is one of L-ascorbic acid, sodium hypophosphite and sodium formaldehyde sulfoxylate, the initiator is one of hydrogen peroxide, sodium persulfate or ammonium persulfate, the chain transfer agent is one of mercaptoacetic acid, mercaptopropionic acid or mercaptoethanol, the pH of a reaction product is adjusted by adopting liquid alkali, and the mass fraction of the liquid alkali is 30-32%.
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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1992010266A1 (en) * 1990-12-04 1992-06-25 Henkel Kommanditgesellschaft Auf Aktien Use of ester-polyol-containing reaction mixtures as foam-inhibiting additives
US6153788A (en) * 1997-08-26 2000-11-28 Bayer Aktiengesellschaft Process for preparing esters of ethylenically unsaturated carboxylic acids
CN102887979A (en) * 2012-10-22 2013-01-23 北京工业大学 Preparation method of star polycarboxylic acid high-performance water reducing agent

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1992010266A1 (en) * 1990-12-04 1992-06-25 Henkel Kommanditgesellschaft Auf Aktien Use of ester-polyol-containing reaction mixtures as foam-inhibiting additives
US6153788A (en) * 1997-08-26 2000-11-28 Bayer Aktiengesellschaft Process for preparing esters of ethylenically unsaturated carboxylic acids
CN102887979A (en) * 2012-10-22 2013-01-23 北京工业大学 Preparation method of star polycarboxylic acid high-performance water reducing agent

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