阅读说明：本技术 一种抗泥型聚羧酸减水剂的制备方法及应用 (Preparation method and application of anti-mud polycarboxylate superplasticizer ) 是由 李才 赵伟民 周柳 索喜梅 于 2019-10-23 设计创作，主要内容包括：本发明涉及一种抗泥型聚羧酸减水剂的制备方法及应用,所述的制备方法具体包括以下步骤：S1：制备抗泥型聚羧酸减水剂母液：将不饱和聚醚大单体、不饱和小单体、乙烯基硅烷偶联剂加入脱盐水溶液中,并在氧化-还原引发剂、链转移剂的作用下进行自由基共聚反应,制备得到抗泥型聚羧酸减水剂母液；S2：制备成品：将步骤S1中制备得到的抗泥型聚羧酸减水剂母液与葡萄糖酸钠、带胺基硅烷偶联剂进行复配得到抗泥型聚羧酸减水剂。本发明提出的一种抗泥型聚羧酸减水剂的制备方法及应用,作为水泥分散剂具有掺量低、保坍时间长和抗泥性强的优点,并且原料利用率高,合成工艺简单。(The invention relates to a preparation method and application of a mud-resistant polycarboxylate superplasticizer, wherein the preparation method specifically comprises the following steps: s1: preparing a mud-resistant polycarboxylate superplasticizer mother solution: adding an unsaturated polyether macromonomer, an unsaturated small monomer and a vinyl silane coupling agent into a desalted water solution, and carrying out free radical copolymerization reaction under the action of an oxidation-reduction initiator and a chain transfer agent to prepare an anti-mud polycarboxylic acid water reducer mother liquor; s2: preparing a finished product: and (4) compounding the anti-mud polycarboxylate superplasticizer mother liquor prepared in the step (S1) with sodium gluconate and an amino silane coupling agent to obtain the anti-mud polycarboxylate superplasticizer. The preparation method and the application of the anti-mud polycarboxylic acid water reducer provided by the invention have the advantages of low mixing amount, long slump retaining time and strong mud resistance as a cement dispersant, and have the advantages of high utilization rate of raw materials and simple synthesis process.)

1. The preparation method of the anti-mud polycarboxylate superplasticizer is characterized by comprising the following steps:

s1: preparing a mud-resistant polycarboxylate superplasticizer mother solution: adding an unsaturated polyether macromonomer, an unsaturated small monomer and a vinyl silane coupling agent into a desalted water solution, and carrying out free radical copolymerization reaction under the action of an oxidation-reduction initiator and a chain transfer agent to prepare an anti-mud polycarboxylic acid water reducer mother liquor;

s2: preparing a finished product: and (4) compounding the anti-mud polycarboxylate superplasticizer mother liquor prepared in the step (S1) with sodium gluconate and an amino silane coupling agent to obtain the anti-mud polycarboxylate superplasticizer.

2. The preparation method of the anti-mud type polycarboxylate superplasticizer according to claim 1, wherein the concrete operation of step S1 is:

s11: fully mixing unsaturated polyether macromonomer, oxidant in an oxidation-reduction initiator and water, and heating to the reaction temperature of 25-50 ℃ in a protective atmosphere;

s12: dropwise adding a material A dropwise solution consisting of unsaturated small monomers and water into the mixed solution obtained in the step S11 for 1-3 h; and simultaneously dropwise adding a B material dropwise adding solution consisting of a reducing agent, a chain transfer agent and water in an oxidation-reduction initiator for 1.5-3.5 h, dropwise adding the B material 0.5h later than the A material, neutralizing the B material with a 32% liquid sodium hydroxide solution after finishing dropwise adding, reacting for 1-2 h at a constant temperature, adjusting the water replenishing to a polymerization concentration of 30-60%, and discharging.

3. The preparation method of the anti-mud polycarboxylic acid water reducer according to claim 1, wherein the unsaturated polyether macromonomer in step S1 has a structural formula:

4. The preparation method of the anti-mud polycarboxylic acid water reducer according to claim 1, characterized in that the unsaturated small monomer in step S1 is one or more of acrylic acid, methacrylic acid, fumaric acid, aconitic acid, 2-acrylamide-2-methylpropanesulfonic acid, acrylamide, maleic anhydride, hydroxyethyl acrylate, and hydroxypropyl acrylate; the molar weight of the unsaturated small monomer is 3-5 times of that of the unsaturated polyether large monomer.

5. The method for preparing the anti-mud type polycarboxylate water reducer according to the claim 1, characterized in that the vinyl silane coupling agent in the step S1 is vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silane or methylvinyldimethoxysilane; the molar weight of the vinyl silane coupling agent is 0.3-2 times of that of the unsaturated polyether macromonomer.

6. The method for preparing the anti-mud type polycarboxylate superplasticizer according to claim 1, wherein the chain transfer agent in step S1 is thioglycolic acid, mercaptopropionic acid, sodium methallylsulfonate, tert-dodecyl mercaptan, isopropanol or mercaptoethanol; the mass of the chain transfer agent is 1 per thousand-2% of that of the unsaturated polyether macromonomer.

7. The preparation method of the anti-mud polycarboxylic acid water reducing agent according to claim 1, characterized in that the oxidant in the oxidation-reduction initiator in step S1 is hydrogen peroxide, ammonium persulfate or potassium persulfate; the reducing agent in the oxidation-reduction initiator is vitamin C, sodium bisulfite, sodium formaldehyde sulfoxylate or ferrous sulfate; the mass of the oxidation-reduction initiator is 1 per thousand-1% of that of the unsaturated polyether.

8. The method for preparing the anti-mud type polycarboxylate superplasticizer according to claim 1, wherein the structural formula of the silane coupling agent with amino group in step S2 is as follows:wherein R1 is-H, -OH or-CH₃R2 and R3 are-CH₂-or-CH₂CH₂-。

9. The preparation method of the anti-mud polycarboxylic acid water reducing agent according to claim 1, characterized in that the radical copolymerization in step 1 is an aqueous radical copolymerization, and the temperature of the aqueous radical copolymerization is 25-50 ℃.

10. The application of the anti-mud polycarboxylate superplasticizer prepared by the preparation method of any one of claims 1 to 9 as a cement dispersant.

Technical Field

The invention relates to the technical field of concrete admixtures, in particular to a preparation method and application of a mud-resistant polycarboxylic acid water reducer.

Background

The polycarboxylate water reducing agent is a high-performance water reducing agent, and is a cement dispersing agent in the application of cement concrete. The method is widely applied to projects such as highways, bridges, dams, tunnels, high-rise buildings and the like. The polycarboxylic acid water reducing agent is used as a third-generation water reducing agent in the concrete industry, and before the polycarboxylic acid additive appears, the polycarboxylic acid water reducing agent comprises a lignosulfonate additive, a naphthalene sulfonate formaldehyde condensate, a melamine formaldehyde polycondensate, an acetone sulfonate formaldehyde condensate, an amino sulfonate formaldehyde condensate and the like. The new generation of polycarboxylic acid high-efficiency water reducing agent overcomes the defects of the traditional water reducing agent, has the outstanding advantages of low mixing amount, good slump keeping performance, low concrete shrinkage, strong adjustability on molecular structure, high potential of high performance, no formaldehyde in the production process, environmental protection and the like, and becomes the most important product in the current concrete admixture market. The polycarboxylate superplasticizer is a comb-shaped water-soluble polymer, and consists of a main chain rich in carboxylic acid groups and side chains of polyoxyalkylene groups.

The common concrete is artificial stone which is prepared by taking cement as a main cementing material, adding water, sand, stones and chemical additives and mineral admixtures if necessary, mixing the materials according to a proper proportion, uniformly stirring, densely molding, curing and hardening. Along with the more and more importance of the country to the environmental protection problem, the management and control to aggregate grit material for the concrete is stricter and stricter, this just leads to aggregate for the concrete to be more and more scarce, and the quality of grit material is more and more poor on the market. The sandstone aggregate has great influence on the quality of concrete, wherein the prominent aspect is that the mud content of the sandstone material is larger and larger, the mud content in the sandstone material is mainly clay, and the main components comprise montmorillonite, illite, kaolin and the like, wherein the montmorillonite has the strongest adsorption on concrete admixtures, particularly water reducing agents, so that the using effect of the water reducing agents in the concrete is hindered, the application effect of the water reducing agents is influenced, and the workability of the concrete is deteriorated. As the polycarboxylate superplasticizer which is the most widely applied water reducer at present, when the polycarboxylate superplasticizer is used as a concrete water reducer in a sand-rock material with large mud content, the mixing amount is increased, the slump loss is accelerated, the workability of concrete is influenced, the performance is greatly influenced, and the research on the mud-resistant polycarboxylate superplasticizer with excellent performance is urgently needed.

Chinese patent document CN201610028121 discloses a preparation method and application of an anti-mud polycarboxylic acid water reducer, wherein the preparation method is obtained by carrying out free radical copolymerization reaction on a specific unsaturated acid monomer, a specific unsaturated polyether macromonomer and a PVP macromonomer containing a poly (N-vinyl pyrrolidone) chain, and the molar weight of the unsaturated polyether macromonomer is 50-100% of that of the PVP macromonomer. The mud-resistant polycarboxylate superplasticizer has the advantages of low mixing amount, high water reducing rate and strong mud resistance, the raw material utilization rate is high, but PVP macromonomer needs to be synthesized firstly, the solvent recovery is troublesome, and the polycarboxylate superplasticizer can be generated only by two-step reaction, so that the process is complicated.

Chinese patent document CN201810249461 provides a normal-temperature early-strength polycarboxylate superplasticizer for prefabricated parts and a preparation method thereof. The polycarboxylate water reducer is adsorbed on the surfaces of cement particles in a single-point or multi-point anchoring mode through carboxyl, phosphate groups, isocyanate end groups and silane coupling agent hydrolyzed oligomers under the actions of ionic bonds, covalent bonds, hydrogen bonds, Van der Waals force and the like, the adsorption mode is more diversified, the early strength of a prefabricated part can be improved, the demolding time of the prefabricated part is shortened, the turnover efficiency of a grinding tool is accelerated, the cost is greatly saved, and the application effect in a sand-stone material with high mud content is poor.

Chinese patent document CN201611067604 provides a high mud resistance type polycarboxylate water reducing agent, which introduces triallyl phosphite and dimethylamino propyl acrylamide as small monomers to participate in synthesizing the polycarboxylate water reducing agent, and aiming at the condition that the mud content of a sand material is higher (the total mud content of sand is about 6% -10%), under the same test environment, the concrete water reducing rate equivalent to that of common polycarboxylate is still achieved while the mixing amount is reduced, and the concrete slump retaining effect is better, and the concrete strength grade can be improved by 1-2. The same effect is achieved when the water reducer is used in combination with other polycarboxylic acid water reducers. But the reaction temperature is required to be above 60 ℃, the reaction materials need to be heated, the reaction requirement condition is high, and the production equipment requirement is high.

Disclosure of Invention

In order to overcome the defects in the prior art, the invention provides a preparation method and application of a mud-resistant polycarboxylate superplasticizer, and solves the technical problems of poor mud resistance, short slump retaining time, low raw material utilization rate and complex synthesis process of the existing mud-resistant polycarboxylate superplasticizer.

The invention is realized by the following technical scheme:

the preparation method of the anti-mud polycarboxylate superplasticizer specifically comprises the following steps:

s1: preparing a mud-resistant polycarboxylate superplasticizer mother solution: adding an unsaturated polyether macromonomer, an unsaturated small monomer and a vinyl silane coupling agent into a desalted water solution, and carrying out free radical copolymerization reaction under the action of an oxidation-reduction initiator and a chain transfer agent to prepare an anti-mud polycarboxylic acid water reducer mother liquor;

s2: preparing a finished product: and (4) compounding the anti-mud polycarboxylate superplasticizer mother liquor prepared in the step (S1) with sodium gluconate and an amino silane coupling agent to obtain the anti-mud polycarboxylate superplasticizer.

Further, the specific operation of step S1 is:

s11: fully mixing unsaturated polyether macromonomer, oxidant in an oxidation-reduction initiator and water, and heating to the reaction temperature of 25-50 ℃ in a protective atmosphere;

s12: dropwise adding a material A dropwise solution consisting of unsaturated small monomers and water into the mixed solution obtained in the step S11 for 1-3 h; and simultaneously dropwise adding a B material dropwise adding solution consisting of a reducing agent, a chain transfer agent and water in an oxidation-reduction initiator for 1.5-3.5 h, dropwise adding the B material 0.5h later than the A material, neutralizing the B material with a 32% liquid sodium hydroxide solution after finishing dropwise adding, reacting for 1-2 h at a constant temperature, adjusting the water replenishing to a polymerization concentration of 30-60%, and discharging.

Protective atmosphere of N₂Or an inert shielding gas. The polymerization concentration refers to the sum of the mass percent concentrations of all monomers in the reaction mixed solution.

Further, the unsaturated polyether macromonomer described in step S1 has the structural formula:

wherein R3 is-H, -OH or-CH₃R4 is-CH₂-or-CH₂CH₂And n is an integer of 25 to 65.

Further, the unsaturated small monomer in step S1 is one or more of acrylic acid, methacrylic acid, fumaric acid, aconitic acid, 2-acrylamide-2-methylpropanesulfonic acid, acrylamide, maleic anhydride, hydroxyethyl acrylate, and hydroxypropyl acrylate; the molar weight of the unsaturated small monomer is 3-5 times of that of the unsaturated polyether large monomer.

Further, the vinyl silane coupling agent described in step S1 is vinyl trimethoxysilane, vinyl triethoxysilane, vinyl tris (2-methoxyethoxy) silane or methyl vinyl dimethoxysilane; the molar weight of the vinyl silane coupling agent is 0.3-2 times of that of the unsaturated polyether macromonomer.

Further, the chain transfer agent in step S1 is thioglycolic acid, mercaptopropionic acid, sodium methallylsulfonate, tert-dodecyl mercaptan, isopropanol or mercaptoethanol; the mass of the chain transfer agent is 1 per thousand-2% of that of the unsaturated polyether macromonomer.

Further, in the step S1, the oxidant in the oxidation-reduction initiator is hydrogen peroxide, ammonium persulfate or potassium persulfate; the reducing agent in the oxidation-reduction initiator is vitamin C, sodium bisulfite, sodium formaldehyde sulfoxylate or ferrous sulfate; the mass of the oxidation-reduction initiator is 1 per thousand-1% of that of the unsaturated polyether.

Further, the silane coupling with amino group described in step S2The structural formula of the agent is:

wherein R1 is-H, -OH or-CH₃R2 and R3 are-CH₂-or-CH₂CH₂-; preferably, R1 is-CH₃(ii) a R2 and R3 are-CH₂-; n is an integer of 1 to 2.

Further, the desalted aqueous solution in step S1 is prepared for an industrial water purifier, and the conductivity is less than 15 us/cm.

Further, the free radical copolymerization reaction in the step 1 is a water-based free radical copolymerization reaction, and the temperature of the water-based free radical copolymerization reaction is 25-50 ℃.

An application of a mud-resistant polycarboxylate superplasticizer as a cement dispersant.

Compared with the prior art, the invention has the beneficial effects that:

the preparation method and the application of the anti-mud polycarboxylic acid water reducing agent provided by the invention have excellent mud resistance, are particularly suitable for areas with high mud content of aggregates, have the advantages of low mixing amount, high water reduction and high slump loss resistance, and are simple in preparation process, green and environment-friendly in production process and low in cost.

Detailed Description

The following examples are presented to illustrate certain embodiments of the invention in particular and should not be construed as limiting the scope of the invention. The present disclosure may be modified from materials, methods, and reaction conditions at the same time, and all such modifications are intended to be within the spirit and scope of the present invention.