阅读说明：本技术 一种有机磷接枝聚羧酸抗泥型减水剂及其制备方法 (Organic phosphorus grafted polycarboxylic acid mud-resistant water reducer and preparation method thereof ) 是由 霍利利 虞亚丽 张军 丁健 傅雁 朱占军 于 2020-06-02 设计创作，主要内容包括：本发明公开了一种抗泥型聚羧酸减水剂,所述减水剂是由有机磷聚羧酸减水剂的主链上而得到的,所述有机磷由有机磷A和有机磷B组成,所述有机磷A为聚氧乙烯醚丙三醇磷酸酯,所述有机磷B选自2-羟基磷酸基乙酸、二乙烯三胺五亚甲基膦酸和2-膦酰基丁烷-1,2,4-三羧酸中的任意一种。本发明还公开了所述有机磷接枝聚羧酸抗泥型减水剂的制备方法。本发明的有机磷接枝聚羧酸抗泥型减水剂,利用具有长效缓凝特殊性能的有机磷接枝在聚羧酸主链上,磷酸基团优先吸附在粘土表面,减弱了黏土对羧酸基团的吸附,从而在含泥量较高的体系中依然保持良好的减水和保坍效果。(The invention discloses a mud-resistant polycarboxylate water reducer which is obtained from the main chain of an organic phosphorus polycarboxylate water reducer, wherein organic phosphorus comprises organic phosphorus A and organic phosphorus B, the organic phosphorus A is polyoxyethylene ether glycerol phosphate, and the organic phosphorus B is selected from any one of 2-hydroxyphosphoric acid, diethylenetriamine pentamethylene phosphonic acid and 2-phosphonobutane-1, 2, 4-tricarboxylic acid. The invention also discloses a preparation method of the organic phosphorus grafted polycarboxylic acid mud-resistant water reducing agent. According to the organic phosphorus grafted polycarboxylic acid mud-resistant water reducing agent, organic phosphorus with long-acting slow-setting special performance is grafted on a polycarboxylic acid main chain, phosphate groups are preferentially adsorbed on the surface of clay, and the adsorption of the clay on carboxylic acid groups is weakened, so that good water reducing and slump retaining effects are still kept in a system with high mud content.)

1. The organic phosphorus grafted polycarboxylic acid mud-resistant water reducing agent is characterized by being obtained by grafting organic phosphorus onto a main chain of a polycarboxylic acid water reducing agent, wherein the organic phosphorus consists of organic phosphorus A and organic phosphorus B, the organic phosphorus A is polyoxyethylene ether glycerol phosphate, and the organic phosphorus B is selected from any one of 2-hydroxyphosphoric acid, diethylenetriamine pentamethylenephosphonic acid and 2-phosphonobutane-1, 2, 4-tricarboxylic acid.

2. The organic phosphorus grafted polycarboxylic acid mud-resistant water reducing agent of claim 1, wherein the mass ratio of the organic phosphorus A to the organic phosphorus B is 1: 1-10.

3. The organophosphorus grafted polycarboxylic acid mud-resistant water reducer according to claim 1 or 2, which is prepared from the following components in percentage by mass:

4. the organophosphorus grafted polycarboxylic acid anti-mud water reducer according to claim 3, wherein the unsaturated polyether is isobutylene alcohol polyoxyethylene ether, and the molecular weight is 2160-3000.

5. The organophosphorus grafted polycarboxylic acid mud-resistant water reducing agent according to claim 3, wherein the unsaturated acid is acrylic acid and/or methacrylic acid.

6. The organophosphorus grafted polycarboxylic acid anti-mud type water reducing agent according to claim 3, wherein the chain transfer agent is thioglycolic acid or mercaptopropionic acid.

7. The organophosphorus grafted polycarboxylic acid anti-mud type water reducing agent according to claim 3, wherein the oxidant is hydrogen peroxide and/or ammonium persulfate.

8. The organophosphorus grafted polycarboxylic acid mud-resistant water reducing agent according to claim 3, wherein the reducing agent is ascorbic acid and/or sodium formaldehyde sulfoxylate.

9. The preparation method of the organophosphorus grafted polycarboxylic acid anti-mud type water reducer according to any one of claims 3 to 8, characterized by comprising the following steps:

preparing an unsaturated acid into a 45-60% aqueous solution, and marking as a first solution; preparing a reducing agent and a chain transfer agent into an aqueous solution with the total concentration of 3-10%, and marking as a second solution; preparing a mixed solution of organic phosphorus A and organic phosphorus B, and marking as a third solution;

preparing unsaturated polyether into an aqueous solution with the concentration of 30-45%, and adding an oxidant to serve as a bottom material;

simultaneously dripping the first solution and the second solution into the base material, starting dripping the third solution after the dripping of the first solution is finished, and continuing dripping the second solution; and continuing the reaction after the dropwise addition is finished, and obtaining the organic phosphorus grafted polycarboxylic acid anti-mud water reducer after the reaction is finished.

Technical Field

The invention relates to the technical field of water reducing agents, and particularly relates to an organic phosphorus grafted polycarboxylic acid mud-resistant water reducing agent and a preparation method thereof.

Background

At present, the polycarboxylic acid water reducing agent has the advantages of low mixing amount, high water reducing rate, good slump retaining property, adjustable functionality, green and environment-friendly production process and the like, and is widely applied to concrete engineering. However, with the rapid development of the building industry, the sandstone resources in China are increasingly deficient, and due to the regional problem, the clay content in the sandstone aggregate is higher in some places, and the performance of the water reducing agent is easily influenced by the adsorption of the clay contained in the sandstone. The clay contains montmorillonite, kaolin, illite, sepiolite and the like, surface layer adsorption and interlayer adsorption can occur, and the interlayer adsorption is a main factor causing poor molecular performance of the polycarboxylate water reducer, so that the phenomena of increased water demand, poor workability, high slump loss, low strength, cracking and the like of concrete are caused, the doping amount of the polycarboxylate water reducer is usually required to be greatly increased to make up, and the potential quality hazard and the cost increase of the concrete are caused.

Researches show that the action mechanism of the clay and the polycarboxylate water reducer has three aspects. 1. Clay adsorbs the surface layer of the polycarboxylate water reducing agent: because the specific surface area of the clay is larger than that of the cement, the surface active adsorption sites are more than that of the cement, and the surface of the clay particles is negatively charged, when the cement and the clay are in the same system, competitive adsorption occurs and a large amount of cement hydration product Ca is adsorbed on the surface of the clay²⁺And the surface adsorption can be formed on the polycarboxylic acid water reducing agent. Therefore, the polycarboxylate water reducing agent can be adsorbed with Ca on the surface of the clay²⁺The complex action is generated and the absorption is carried out on the surface of the clay, which leads to the quantitative change of the polycarboxylate water reducing agent used for dispersing cement particlesLess, thereby reducing the fluidity of the mortar. 2. Interlayer adsorption of clay on the polycarboxylate superplasticizer: because the internal structure of the clay is of a layered structure, the polycarboxylate water reducing agent is of a comb-shaped configuration with side chains, and the side chains of the polycarboxylate water reducing agent contain polyoxyethylene (-CH)₂—CH₂-O) -structural unit, wherein oxygen atoms are adsorbed between clay layers by water as a bridging group to form hydrogen bonds with Si-OH between clay mineral layers, thereby forming intercalation adsorption. Thereby consuming part of polycarboxylate water reducing agent, reducing the amount of polycarboxylate water reducing agent for dispersing cement and reducing the fluidity of mortar. 3. Adsorption of clay mixing water: the specific surface area of the clay particles is large, and in a cement gelling system, the clay particles reduce the surface energy of the clay particles by adsorbing a polycarboxylic acid water reducing agent and water molecules. This causes the free water of the dispersed cement particles to be adsorbed, resulting in poor net slurry fluidity.

Based on the mechanism of action of the clay on the polycarboxylate water reducer, in order to solve the problem on the market, the clay is generally used for improving the mixing amount of the polycarboxylate water reducer and compounding the polycarboxylate water reducer with the retarder, so that a certain retarding effect can be exerted on concrete, the phenomenon that the concrete loss is too fast is relieved, and the problem of high cost cannot be solved.

Disclosure of Invention

The invention aims to solve the technical problem of providing an organophosphorus grafted polycarboxylic acid anti-mud water reducer, which utilizes organophosphorus with long-acting slow-setting special performance to be grafted on the main chain terminal of polycarboxylic acid, so as to increase the molecular weight and ensure that the organophosphorus is not easy to enter into clay layers; the organic phosphorus A and the organic phosphorus B are matched for use, so that a complexing effect is achieved, the interlayer distance of the clay is reduced, phosphate groups are preferentially adsorbed on the surface of the clay, and the adsorption of the clay on carboxylic acid groups is weakened, so that a good water reducing and slump retaining effect is still kept in a system with a high mud content.

In order to solve the technical problems, the invention provides the following technical scheme:

in a first aspect, the invention provides an organophosphorus grafted polycarboxylic acid anti-mud water reducing agent, which is obtained by grafting organophosphorus on a main chain terminal of a polycarboxylic acid water reducing agent, wherein the organophosphorus consists of organophosphorus A and organophosphorus B, the organophosphorus A is polyoxyethylene ether glycerol phosphate, and the organophosphorus B is selected from any one of 2-hydroxyphosphonoacetic acid (HPAA), diethylenetriamine pentamethylenephosphonic acid (DTPMPA) and 2-phosphonobutane-1, 2, 4-tricarboxylic acid (PBTC).

In the invention, organic phosphorus is grafted at the main chain terminal of the polycarboxylate superplasticizer, so that the polycarboxylate superplasticizer has the functions of mud content resistance and retardation. The water reducing agent is used in high-mud-content aggregate and is not in direct contact with the surface of clay, so that the water reducing agent has a good slump retaining effect in the aggregate with higher mud content.

Further, the mass ratio of the organic phosphorus A to the organic phosphorus B is 1: 1-10, preferably 1: 4.

Further, the water reducing agent is prepared from the following components in percentage by mass:

further, the unsaturated polyether is isobutylene alcohol polyoxyethylene ether, the molecular weight is 2160-3000, and the molecular weight is 2400 is preferred.

Further, the unsaturated acid is acrylic acid and/or methacrylic acid.

Further, the chain transfer agent is thioglycolic acid or mercaptopropionic acid.

Further, the oxidant is hydrogen peroxide and/or ammonium persulfate.

Further, the reducing agent is ascorbic acid and/or sodium formaldehyde sulfoxylate.

In a second aspect, the invention also provides a preparation method of the organophosphorus grafted polycarboxylic acid anti-mud type water reducing agent, which comprises the following steps:

preparing an unsaturated acid into a 45-60% aqueous solution, and marking as a first solution; preparing a reducing agent and a chain transfer agent into an aqueous solution with the total concentration of 3-10%, and marking as a second solution; preparing a mixed solution of organic phosphorus A and organic phosphorus B, and marking as a third solution; preparing unsaturated polyether into an aqueous solution with the concentration of 30-45%, and adding an oxidant to serve as a bottom material;

and (3) simultaneously dripping the first solution and the second solution into the backing material, starting dripping the third solution after the dripping of the first solution is finished, continuing dripping the second solution, continuing to react after the dripping is finished, and obtaining the organophosphorus grafted polycarboxylic acid anti-mud type water reducer after the reaction is finished.

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

1. the organic phosphorus grafted polycarboxylic acid mud-resistant water reducing agent has strong dispersing capacity and selective adsorption capacity, and has a slump retaining effect while maintaining a good water reducing effect in aggregates with high mud content.

2. The production process of the invention has the advantages of low cost of raw materials, capability of reacting at normal temperature, no use of heat source, simplicity, high efficiency, energy saving and great cost saving.

Detailed Description

The present invention is further described below in conjunction with specific examples to enable those skilled in the art to better understand the present invention and to practice it, but the examples are not intended to limit the present invention.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

The experimental procedures used in the following examples are all conventional procedures unless otherwise specified. Materials, reagents and the like used in the following examples are commercially available unless otherwise specified.