阅读说明：本技术 一种双羧基磺酸基聚羧酸减水剂及其制备方法 (Dicarboxyl sulfonic acid group polycarboxylic acid water reducing agent and preparation method thereof ) 是由 李良滢 潘呈恭 易书城 张丹 李小林 于 2020-05-26 设计创作，主要内容包括：一种双羧基磺酸基聚羧酸减水剂,包括如下重量份组分：32-48份单体A、2-10份单体B、1-6份单体C、0.1-0.8份甲基丙烯磺酸钠、0.1-0.3份链转移剂、0.4-1份引发剂、50-60份水。本发明双羧基磺酸基聚羧酸减水剂,通过在主链上加入部分含有-C＝C-双键的带有阴离子强极性基团,作为锚定基团,有效提高了减水剂的吸附能力,可有效提高混凝土的分散性能和流变性能,满足施工需求。(A dicarboxyl sulfonic acid group polycarboxylate superplasticizer comprises the following components in parts by weight: 32-48 parts of monomer A, 2-10 parts of monomer B, 1-6 parts of monomer C, 0.1-0.8 part of sodium methallyl sulfonate, 0.1-0.3 part of chain transfer agent, 0.4-1 part of initiator and 50-60 parts of water. According to the dicarboxyl sulfonic acid group polycarboxylate water reducer, a part of anionic strong polar groups with-C ═ C-double bonds are added to the main chain and are used as anchoring groups, so that the adsorption capacity of the water reducer is effectively improved, the dispersion performance and rheological performance of concrete can be effectively improved, and the construction requirements are met.)

1. The dicarboxyl sulfonic acid group polycarboxylate superplasticizer is characterized by comprising the following components in parts by weight:

32-48 parts of monomer A, 2-10 parts of monomer B, 1-6 parts of monomer C, 0.1-0.8 part of sodium methallyl sulfonate, 0.1-0.3 part of chain transfer agent, 0.4-1 part of initiator and 50-60 parts of water;

the monomer A is methyl alkenyl polyoxyethylene ether or isobutenol polyoxyethylene ether; the monomer B is acrylic acid; the monomer C is unsaturated dibasic acid; the initiator is hydrogen peroxide and ascorbic acid; the chain transfer agent is mercaptoethanol; the molecular structural formula of the dicarboxyl sulfonic acid group polycarboxylate superplasticizer is as follows:

wherein x is more than or equal to 25 and less than or equal to 45, y is more than or equal to 20 and less than or equal to 55, z is more than or equal to 15 and less than or equal to 25, h is more than or equal to 5 and less than or equal to 20, and n is more than or equal to 30 and less than or equal to 60.

2. The dicarboxyl sulfonic acid based polycarboxylate superplasticizer of claim 1, which is characterized by comprising the following components in parts by weight:

35-43 parts of monomer A, 3-7 parts of monomer B, 1-4 parts of monomer C, 0.2-0.5 part of sodium methallyl sulfonate, 0.1-0.2 part of chain transfer agent, 0.4-0.8 part of initiator and 50-55 parts of water.

3. The dicarboxyl sulfonic acid based polycarboxylate superplasticizer of claim 1, which is characterized by comprising the following components in parts by weight:

40.3 parts of monomer A, 3.6 parts of monomer B, 1.3 parts of monomer C, 0.4 part of sodium methallyl sulfonate, 0.2 part of chain transfer agent, 0.7 part of initiator and 53.5 parts of water.

4. The biscarboxylate polycarboxylate superplasticizer according to any one of claims 1-3, wherein said methyl alkenyl polyoxyethylene ether has an average molecular weight of 2400 and said isobutylene alcohol polyoxyethylene ether has an average molecular weight of 3000.

5. The dicarboxyl sulfonic acid based polycarboxylate superplasticizer according to any one of claims 1 to 3, wherein the unsaturated dibasic acid is any one or a mixture of fumaric acid, maleic acid and itaconic acid.

6. The polycarboxyl sulfonic acid based polycarboxylate water reducing agent as claimed in any one of claims 1 to 3, wherein the hydrogen peroxide is a 30 wt% aqueous solution, and the mass ratio of hydrogen peroxide to ascorbic acid is 2: 1.

7. the preparation method of the dicarboxyl sulfonic acid based polycarboxylate superplasticizer of any one of claims 1 to 6 is characterized by comprising the following steps:

1) taking materials according to a proportion;

2) dissolving the monomer A and the monomer C with water to obtain a first monomer solution, dissolving the chain transfer agent and the ascorbic acid with water to obtain a chain transfer agent solution, and dissolving the monomer B and the sodium methallyl sulfonate with water to obtain a second monomer solution;

3) heating the first monomer solution to 44-50 ℃, adding hydrogen peroxide, keeping the temperature and stirring for 3-6min, then dropwise adding a chain transfer agent at a constant speed for 3-5h, then uniformly dropwise adding a second monomer solution for 2-4 h;

4) and continuously preserving the heat for reaction for 1-2h to obtain the target product.

8. The method according to claim 7, wherein the mass ratio of water in the first monomer solution to water in the chain transfer agent to water in the second monomer solution is 8: 1: 1.

9. the preparation method according to claim 7, wherein the step 4) is carried out for 1 hour under heat preservation.

10. The preparation method of claim 7, wherein in the step 3), the temperature of the first monomer solution is raised to 47 ℃, hydrogen peroxide is added, the temperature is kept and the stirring is carried out for 5min, the dripping-off time of the chain transfer agent is 3.5h, after 5min, the second monomer solution is dripped, and the dripping-off time of the second monomer solution is 3 h.

Technical Field

The invention relates to the field of building materials, and particularly relates to a dicarboxyl sulfonic acid group polycarboxylic acid water reducing agent and a preparation method thereof.

Background

The polycarboxylate superplasticizer is a surfactant, and the molecular structure of the polycarboxylate superplasticizer generally contains a hydrophilic main chain and a hydrophobic polyoxyethylene side chain. The polycarboxylic acid water reducing agent commonly used at present can cause the problem of cement adaptability due to the weak adsorption capacity of monocarboxyl-COOH-groups on the main chain. Sulfate generated by cement hydration generates competitive adsorption with the polycarboxylate water reducer, so that the energy absorption capacity of the polycarboxylate water reducer is influenced, and the performance of the polycarboxylate water reducer is seriously reduced. Therefore, how to provide a polycarboxylic acid water reducing agent with high adsorption capacity for improving the dispersion performance and rheological property of concrete is a problem to be solved by those skilled in the art.

Disclosure of Invention

One of the purposes of the invention is to provide a dicarboxyl sulfonic acid group polycarboxylate water reducer aiming at the defects of the prior art, wherein a part of anionic strong polar groups with-C ═ C-double bonds are added to the main chain to serve as anchoring groups, so that the adsorption capacity of the water reducer is effectively improved, the dispersion performance and rheological performance of concrete can be effectively improved, and the construction requirements are met.

The invention also aims to provide the preparation method of the polycarboxylate superplasticizer, which has simple and convenient preparation process and mild technological parameters and is suitable for industrial processing production.

The technical scheme for realizing one purpose of the invention is as follows: a dicarboxyl sulfonic acid group polycarboxylate superplasticizer comprises the following components in parts by weight:

32-48 parts of monomer A, 2-10 parts of monomer B, 1-6 parts of monomer C, 0.1-0.8 part of sodium methallyl sulfonate, 0.1-0.3 part of chain transfer agent, 0.4-1 part of initiator and 50-60 parts of water;

the monomer A is methyl alkenyl polyoxyethylene ether or isobutenol polyoxyethylene ether; the monomer B is acrylic acid; the monomer C is unsaturated dibasic acid; the initiator is hydrogen peroxide and ascorbic acid; the chain transfer agent is mercaptoethanol; the molecular structural formula of the dicarboxyl sulfonic acid group polycarboxylate superplasticizer is as follows:

wherein x is more than or equal to 25 and less than or equal to 45, y is more than or equal to 20 and less than or equal to 55, z is more than or equal to 15 and less than or equal to 25, h is more than or equal to 5 and less than or equal to 20, and n is more than or equal to 30 and less than or equal to 60.

Preferably, the dicarboxyl sulfonic acid group polycarboxylate superplasticizer comprises the following components in parts by weight:

35-43 parts of monomer A, 3-7 parts of monomer B, 1-4 parts of monomer C, 0.2-0.5 part of sodium methallyl sulfonate, 0.1-0.2 part of chain transfer agent, 0.4-0.8 part of initiator and 50-55 parts of water.

Preferably, the dicarboxyl sulfonic acid group polycarboxylate superplasticizer comprises the following components in parts by weight:

40.3 parts of monomer A, 3.6 parts of monomer B, 1.3 parts of monomer C, 0.4 part of sodium methallyl sulfonate, 0.2 part of chain transfer agent, 0.7 part of initiator and 53.5 parts of water.

Further, the average molecular weight of the methyl alkenyl polyoxyethylene ether is 2400, and the average molecular weight of the isobutylene alcohol polyoxyethylene ether is 3000.

Further, the unsaturated dibasic acid is one or a mixture of fumaric acid, maleic acid and itaconic acid.

Further, the hydrogen peroxide is a 30 wt% aqueous solution, and the mass ratio of the hydrogen peroxide to the ascorbic acid is 2: 1.

the second technical scheme for realizing the aim of the invention is as follows: the preparation method of the dicarboxyl sulfonic acid group polycarboxylate superplasticizer comprises the following steps:

1) taking materials according to a proportion;

2) dissolving the monomer A and the monomer C with water to obtain a first monomer solution, dissolving the chain transfer agent and the ascorbic acid with water to obtain a chain transfer agent solution, and dissolving the monomer B and the sodium methallyl sulfonate with water to obtain a second monomer solution;

3) heating the first monomer solution to 44-50 ℃, adding hydrogen peroxide, keeping the temperature and stirring for 3-6min, then dropwise adding a chain transfer agent at a constant speed for 3-5h, then uniformly dropwise adding a second monomer solution for 2-4 h;

4) and continuously preserving the heat for reaction for 1-2h to obtain the target product.

Preferably, the mass ratio of water in the first monomer solution, the chain transfer agent and the second monomer solution is 8: 1: 1.

preferably, the step 4) is carried out for 1 hour under the condition of heat preservation.

Preferably, in the step 3), the temperature of the first monomer solution is raised to 47 ℃, hydrogen peroxide is added, the heat preservation and stirring are carried out for 5min, the dripping-off time of the chain transfer agent is 3.5h, the second monomer solution is dripped after the dripping-off of the chain transfer agent is finished for 5min, and the dripping-off time of the second monomer solution is 3 h.

Adopt above-mentioned technical scheme to have following beneficial effect:

1. the dicarboxyl sulfonic acid group polycarboxylate superplasticizer takes methyl alkenyl polyoxyethylene ether or isobutenol polyoxyethylene ether as a macromonomer, takes unsaturated monocarboxylic acid as a monomer B, takes unsaturated dibasic acid as a monomer C, and copolymerizes the monomer A, B, C and sodium methallyl sulfonate to obtain the dicarboxyl sulfonic acid group polycarboxylate superplasticizer with the water reducing rate of over 41 percent (the water reducing rate of the same type of water reducers on the market is generally below 40 percent), the concrete slump retaining performance of the water reducer added with the water reducer is excellent, and the concrete pressure bleeding rate is lower than 15 percent (the concrete pressure bleeding rate of the same type of water reducers on the market is generally about 40 percent). The conversion rate of the water reducer mother liquor can be reduced along with the increase of the substitution ratio of the unsaturated dibasic acid, the substitution ratio is too low, the performance of the water reducer mother liquor cannot be improved, and when the substitution ratio of the unsaturated dibasic acid is 20%, the effect of the water reducer is optimal and the conversion rate is qualified; the sodium methallyl sulfonate has the function of adjusting the molecular weight, if the substitution proportion of the sodium methallyl sulfonate is too high, the molecular weight of the mother liquor of the water reducing agent can be greatly reduced, and when the substitution proportion of the sodium methallyl sulfonate is 5%, the effect of the water reducing agent is optimal and the molecular weight is qualified.

2. According to the dicarboxyl sulfonic acid group polycarboxylic acid water reducing agent, the used sodium methallyl sulfonate is used as a small monomer to replace part of unsaturated monobasic acid, and is used as part of chain transfer agent, so that the price of the sodium methallyl sulfonate is low, and the production cost of the water reducing agent can be greatly reduced.

3. According to the dicarboxyl sulfonic acid group polycarboxylate water reducer, the main chain is grafted with dicarboxyl and sulfonic acid groups, and the adsorption capacity of the dicarboxyl and the sulfonic acid groups is higher than that of the monocarboxyl, so that the adsorption capacity of the polycarboxylate water reducer can be improved, and the dispersion performance and rheological property of concrete can be effectively improved. The tests of the applicant prove that the concrete added with the dicarboxyl sulfonic acid group polycarboxylate superplasticizer has higher water reducing rate, better slump retaining performance and low pressure bleeding rate.

4. According to the dicarboxyl sulfonic acid group polycarboxylate superplasticizer, the main chain is grafted with dicarboxyl and sulfonic acid groups, so that the problem of competitive adsorption sensitivity of sulfate is effectively solved.

5. According to the preparation method, the polycarboxylate superplasticizer product with high water reducing capacity, high slump loss resistance and strong adsorption capacity is prepared under an oxidation-reduction system by controlling the material proportion and the specific charging sequence.

The following description will be further described with reference to specific examples.

Detailed Description

In the invention, the following raw materials are used:

polyether type: sichuan Oak chemical Co., Ltd; OXHP-702; the content is as follows: more than or equal to 97 percent;

hydrogen peroxide: chongqing south coast east reagents, Inc.; the content is more than or equal to 27.5 percent;

vc sodium is Baijiweiqi Vc sodium Co., Dexing, Jiangxi province; the content is more than or equal to 98 percent;

mercaptoethanol: chongqing south coast east reagents, Inc.; the content is more than or equal to 99 percent;

acrylic acid: weichai industrialism Limited in lake south China; the content is more than or equal to 99 percent;

fumaric acid: zibo Jusi specialized chemical Co., Ltd; the content is more than or equal to 99 percent;

sodium methallyl sulfonate: zibo Australia chemical Co., Ltd; the content is more than or equal to 98 percent.