阅读说明：本技术 一种固体聚羧酸保坍剂的制备方法 (Preparation method of solid polycarboxylic acid slump retaining agent ) 是由 朱建民 刘兆滨 董振鹏 杨雪 于 2018-08-20 设计创作，主要内容包括：本发明提供一种固体聚羧酸保坍剂的制备方法,包括：将不饱和聚氧乙烯醚升温加热至熔融态后加入分散剂及不饱和酯类单体,得第一混合物料；配制滴加料,所述滴加料包括不饱和羧酸或其盐、不饱和羧酸酯、链转移剂和阻聚剂；向所述第一混合物料中加入引发剂及10％～20％的所述滴加料,搅拌均匀,得第二混合物料；向所述第二混合物料中滴加剩余的所述滴加料,所述滴加后进行老化处理；所述老化处理后出料切片,即得所述固体聚羧酸保坍剂。该方法制备过程中不需要有机溶剂,环境友好,无需后处理,工艺简单,且不饱和聚氧乙烯醚的转化率高,所得产品保坍效果好。(The invention provides a preparation method of a solid polycarboxylic slump retaining agent, which comprises the following steps: heating unsaturated polyoxyethylene ether to a molten state, and adding a dispersing agent and an unsaturated ester monomer to obtain a first mixed material; preparing a dropwise material, wherein the dropwise material comprises unsaturated carboxylic acid or salt thereof, unsaturated carboxylic ester, a chain transfer agent and a polymerization inhibitor; adding an initiator and 10-20% of the dropwise added materials into the first mixed material, and uniformly stirring to obtain a second mixed material; dropwise adding the rest of the dropwise added materials into the second mixed material, and carrying out aging treatment after dropwise adding; and discharging and slicing after the aging treatment to obtain the solid polycarboxylic acid slump retaining agent. The method has the advantages of no need of organic solvent in the preparation process, environmental friendliness, no need of post-treatment, simple process, high conversion rate of unsaturated polyoxyethylene ether and good slump retaining effect of the obtained product.)

1. A preparation method of a solid polycarboxylic slump retaining agent comprises the following steps:

heating unsaturated polyoxyethylene ether to a molten state, and adding a dispersing agent and an unsaturated ester monomer to obtain a first mixed material;

preparing a dropwise material, wherein the dropwise material comprises unsaturated carboxylic acid or salt thereof, unsaturated carboxylic ester, a chain transfer agent and a polymerization inhibitor;

adding an initiator and 10-20% of the dropwise added materials into the first mixed material, and uniformly stirring to obtain a second mixed material;

dropwise adding the rest of the dropwise added materials into the second mixed material, and carrying out aging treatment after dropwise adding;

and discharging and slicing after the aging treatment to obtain the solid polycarboxylic acid slump retaining agent.

2. The method of claim 1, wherein the dispersant is a fatty acid polyoxyethylene polyoxypropylene ether having the following structural formula:

wherein R is₁Is C₁₂～C₁₆Alkyl of R₂Is C₂～C₄N is an integer of 2 to 50, R₃Is OCH₃、OCH₂CH₃。

3. The method according to claim 2, wherein the dispersant is one or more selected from the group consisting of methyl oleate, methyl stearate, methyl laurate and maleate.

4. The preparation method according to claim 1, wherein the unsaturated ester monomer is polyethylene glycol maleate with a molecular weight of 100-1000, and the polyethylene glycol maleate has a structural formula as follows:

wherein R is₄Is C₂～C₄N is an integer of 2 to 20.

5. The preparation method according to claim 1, wherein the unsaturated polyoxyethylene ether is selected from one or more of prenyl polyoxyethylene ether, methallyl polyoxyethylene ether, allyl polyoxyethylene ether and vinyl hydroxybutyl polyoxyethylene ether, and the average addition number of the unsaturated polyoxyethylene ether is 10-100.

6. The preparation method according to claim 1, wherein the molar ratio of the unsaturated polyoxyethylene ether to the unsaturated carboxylic acid or the salt thereof is 1: 1-6: 1, the molar ratio of the unsaturated polyoxyethylene ether to the unsaturated ester monomer is 1: 1-5: 1, the dispersing agent is 0.1-5% by mass of the unsaturated polyoxyethylene ether monomer, the initiator is 0.5-1% by mass of the unsaturated polyoxyethylene ether monomer, and the chain transfer agent is 0.1-1% by mass of the unsaturated polyoxyethylene ether monomer.

7. The production method according to claim 1, wherein the unsaturated carboxylic acid or a salt thereof is selected from one or more of methacrylic acid, acrylic acid, and maleic anhydride; the unsaturated carboxylic ester is selected from one or more of hydroxyethyl acrylate, hydroxypropyl acrylate, methyl methacrylate, hydroxyethyl methacrylate and hydroxypropyl methacrylate; the initiator is selected from one or more of azobisisobutyronitrile, azobisisoheptonitrile, dimethyl azobisisobutyrate, benzoyl peroxide, sodium persulfate, ammonium persulfate, potassium persulfate and azobisisobutyramidine hydrochloride; the chain transfer agent is selected from one or more of 3-mercaptopropionic acid, thioglycolic acid, mercaptoethanol, sodium hypophosphite and sodium bisulfite.

8. The method according to claim 1, wherein the temperature reached after the temperature rise heating is 65 to 85 ℃.

9. The method according to claim 1, wherein the stirring time is 5 to 60min, preferably 10 min.

10. The preparation method according to claim 1, wherein the dropping time is 1 to 10 hours, preferably 1 hour; the aging treatment time is 1-10 hours, preferably 2 hours.

Technical Field

The invention relates to the field of chemical manufacturing, in particular to a preparation method of a solid polycarboxylic slump retaining agent.

Background

Concrete is the building material with the largest using amount at present, and can be expected to have irreplaceable effect in the building industry for a long time in the future, and the additive is used as a fifth component in the concrete except for cementing materials, sand, stones and water, so that research and development on the additive have important boosting effect on the technical development of the concrete. The water reducing agent is the most used one in the concrete admixture, and the main function of the water reducing agent is to greatly improve the workability and the fluidity of the concrete. The polycarboxylic acid high-performance water reducing agent is used as a third-generation water reducing agent product, and rapidly occupies a large market due to the advantages of high water reducing rate, good slump retaining performance, molecular design diversity, low shrinkage rate and the like. At present, most of the research on the synthesis of the polycarboxylic acid water reducing agent is obtained by aqueous solution polymerization, and most of the commercially available polycarboxylic acid products are water-soluble type with the concentration of 20-50%. The liquid polycarboxylic acid product is inconvenient to package and transport, causes the transport cost to be greatly increased when the construction site is far away, and cannot be used in the situation that a solid high-efficiency water reducing agent is needed, such as dry-mixed mortar, and the like, so the development of the high-concentration or solid polycarboxylic acid product is the primary condition for reducing the transport cost and popularizing the wide use of the polycarboxylic acid water reducing agent (or slump retaining agent) in various places.

At present, reports on a preparation method of a solid polycarboxylic acid slump retaining agent are provided, for example, a research on synthesis and application performance of a slow-release solid polycarboxylic acid water reducing agent introduces a novel solid slow-release polycarboxylic acid slump retaining agent PC-S2 synthesized by adopting an oil-soluble initiating system, taking isoprene polyoxyethylene ether (TPEG), Methacrylic Acid (MA) and Dimethyl Maleate (DM) as polymerization monomers and mercaptoethanol as a chain transfer agent through bulk polymerization in an environment without any solvent. CN106589261A is a method of polymerizing unsaturated polyether monomer and esterified monomer with acrylic acid, and dropping the obtained product by using an initiator, a chain transfer agent and an organic solvent. And after the reaction is finished, removing the organic solvent by using a vacuum pump, and slicing the product to obtain the solid polycarboxylic acid slump retaining agent. In CN106832148A, maleic anhydride and ditrimethylolpropane are used for preparing an ester monomer under the action of a catalyst, and the ester monomer, isopentenol polyoxyethylene ether and acrylic acid are subjected to bulk polymerization under the action of a composite initiator and a hydrophobic chain transfer agent to obtain a molten polycarboxylic acid slump retaining agent, and finally the molten polycarboxylic acid slump retaining agent is condensed and sliced to obtain a product.

Therefore, it is desirable to provide a new method for preparing a solid polycarboxylic slump retaining agent to solve the above problems.

It is noted that the information disclosed in the foregoing background section is only for enhancement of background understanding of the invention and therefore it may contain information that does not constitute prior art that is already known to a person of ordinary skill in the art.

Disclosure of Invention

The invention aims to provide a preparation method of a solid polycarboxylic acid slump retaining agent, and aims to solve the problems of low polyether conversion rate, complex reaction process, easy organic solvent pollution and residue and the like in the existing preparation process of the solid polycarboxylic acid slump retaining agent.

In order to achieve the purpose, the invention adopts the following technical scheme:

the invention provides a preparation method of a solid polycarboxylic slump retaining agent, which comprises the following steps:

heating unsaturated polyoxyethylene ether to a molten state, and adding a dispersing agent and an unsaturated ester monomer to obtain a first mixed material;

preparing a dropwise material, wherein the dropwise material comprises unsaturated carboxylic acid or salt thereof, unsaturated carboxylic ester, a chain transfer agent and a polymerization inhibitor;

adding an initiator and 10-20% of the dropwise added materials into the first mixed material, and uniformly stirring to obtain a second mixed material;

dropwise adding the rest of the dropwise added materials into the second mixed material, and carrying out aging treatment after dropwise adding;

and discharging and slicing after the aging treatment to obtain the solid polycarboxylic acid slump retaining agent.

According to one embodiment of the present invention, the dispersant is a fatty acid polyoxyethylene polyoxypropylene ether having the following structural formula:

wherein R is₁Is C₁₂～C₁₆Alkyl of R₂Is C₂～C₄N is an integer of 2 to 50, R₃Is OCH₃、OCH₂CH₃。

According to one embodiment of the invention, the dispersant is selected from one or more of methyl oleate, methyl stearate, methyl laurate and maleate.

According to one embodiment of the invention, the unsaturated ester monomer is polyethylene glycol maleate with a molecular weight of 100-1000, and the polyethylene glycol maleate has a structural formula as follows:

wherein R is₄Is C₂～C₄N is an integer of 2 to 20.

According to one embodiment of the invention, the unsaturated polyoxyethylene ether is selected from one or more of isoamylene alcohol polyoxyethylene ether, methyl allyl polyoxyethylene ether, allyl polyoxyethylene ether and vinyl hydroxybutyl polyoxyethylene ether, and the average addition number of the unsaturated polyoxyethylene ether is 10-100.

According to one embodiment of the invention, the molar ratio of the unsaturated polyoxyethylene ether to the unsaturated carboxylic acid or the salt thereof is 1: 1-6: 1, the molar ratio of the unsaturated polyoxyethylene ether to the unsaturated ester monomer is 1: 1-5: 1, the dispersing agent is 0.1-5% of the mass of the unsaturated polyoxyethylene ether monomer, the initiator is 0.5-1% of the mass of the unsaturated polyoxyethylene ether monomer, and the chain transfer agent is 0.1-1% of the mass of the unsaturated polyoxyethylene ether monomer.

According to one embodiment of the present invention, the unsaturated carboxylic acid or salt thereof is selected from one or more of methacrylic acid, acrylic acid, maleic anhydride; the unsaturated carboxylic ester is selected from one or more of hydroxyethyl acrylate, hydroxypropyl acrylate, methyl methacrylate, hydroxyethyl methacrylate and hydroxypropyl methacrylate; the initiator is selected from one or more of azobisisobutyronitrile, azobisisoheptonitrile, dimethyl azobisisobutyrate, benzoyl peroxide, sodium persulfate, ammonium persulfate, potassium persulfate and azobisisobutyramidine hydrochloride; the chain transfer agent is selected from one or more of 3-mercaptopropionic acid, thioglycolic acid, mercaptoethanol, sodium hypophosphite and sodium bisulfite.

According to one embodiment of the present invention, the temperature reached after the temperature rise heating is 65 to 85 ℃.

According to one embodiment of the invention, the stirring time is 5-60 min, preferably 10 min.

According to one embodiment of the present invention, the dropping time is 1 to 10 hours, preferably 1 hour.

According to one embodiment of the present invention, the aging treatment time is 1 to 10 hours, preferably 2 hours.

According to the technical scheme, the invention has the beneficial effects that:

the invention provides a novel preparation method of a solid polycarboxylic acid slump retaining agent, which does not need an organic solvent in the preparation process, is environment-friendly, and the added novel dispersing agent can effectively reduce the system viscosity and improve the conversion rate of unsaturated polyoxyethylene ether, and the conversion rate of the final product can reach 100%; in addition, the unsaturated ester monomer added in the reaction system can effectively improve the slow release effect of the product, and the product does not collapse in 3 hours; in addition, in the process of the dripping process, part of the dripping materials are added in advance, and then the pH value is adjusted for further reaction, so that the product performance is improved, and the conversion rate of the unsaturated polyoxyethylene ether is improved.

Detailed Description

The following provides many different embodiments, or examples, for implementing different features of embodiments of the invention. The following specific examples are provided to simplify the present disclosure. These are, of course, merely examples and are not intended to limit embodiments of the invention. In the following description, descriptions of well-known technologies are omitted so as to avoid unnecessarily obscuring the concepts of the present invention.

The invention provides a preparation method of a solid polycarboxylic slump retaining agent, which comprises the steps of carrying out free radical polymerization on unsaturated polyoxyethylene ether, an unsaturated ester monomer, unsaturated carboxylic acid or salt thereof and a dispersing agent under the action of an initiator and a chain transfer agent, conveying an obtained product to a slicer through a heat-insulation pipeline, and slicing to obtain a white powdery solid polycarboxylic slump retaining agent. Specifically, the method comprises the following steps:

heating unsaturated polyoxyethylene ether to a molten state, and adding a dispersing agent and an unsaturated ester monomer to obtain a first mixed material;

preparing a dropwise material, wherein the dropwise material comprises unsaturated carboxylic acid or salt thereof, unsaturated carboxylic ester, a chain transfer agent and a polymerization inhibitor;

adding an initiator and 10-20% of the dropwise added materials into the first mixed material, and uniformly stirring to obtain a second mixed material;

dropwise adding the rest of the dropwise added materials into the second mixed material, and carrying out aging treatment after dropwise adding;

and discharging and slicing after the aging treatment to obtain the solid polycarboxylic acid slump retaining agent.

In some embodiments, the dispersant is a fatty acid polyoxyethylene polyoxypropylene ether having the following structural formula:

wherein R is₁Is C₁₂～C₁₆Alkyl of R₂Is C₂～C₄N is an integer of 2 to 50, R₃Is OCH₃、OCH₂CH₃。

In some embodiments, such dispersants include, but are not limited to, methyl oleate, methyl stearate, methyl laurate, maleates, and the like.

The novel dispersing agent is introduced into a reaction system, so that the viscosity of the system can be effectively reduced, the conversion rate of unsaturated polyoxyethylene ether is improved, and the conversion rate of a final product is improved to basically reach 100%.

In some embodiments, the unsaturated ester monomer is polyethylene glycol maleate with a molecular weight of 100-1000, and the polyethylene glycol maleate has the following structural formula:

wherein R is₄Is C₂～C₄N is an integer of 2 to 20.

By adding the unsaturated ester monomer into the reaction system, the slow release effect of the solid polycarboxylic acid slump retaining agent product can be improved, and the concrete has no collapse loss within 3 hours. In addition, in the preparation process of the solid polycarboxylic acid slump retaining agent, as the bulk polymerization system has no solvent, in order to ensure that the first mixed material and the dropwise added material are better polymerized, partial dropwise added material is added into the first mixed material in advance, so that the reactivity ratios of the two materials are better matched, the product performance is favorably improved, and the conversion rate of unsaturated polyoxyethylene ether is improved.

In some embodiments, the molar ratio of the unsaturated polyoxyethylene ether to the unsaturated carboxylic acid or the salt thereof is 1:1 to 6:1, the molar ratio of the unsaturated polyoxyethylene ether to the unsaturated ester monomer is 1:1 to 5:1, the dispersant is 0.1 to 5% by mass of the unsaturated polyoxyethylene ether monomer, the initiator is 0.5 to 1% by mass of the unsaturated polyoxyethylene ether monomer, and the chain transfer agent is 0.1 to 1% by mass of the unsaturated polyoxyethylene ether monomer.

In some embodiments, the unsaturated polyoxyethylene ether includes, but is not limited to, prenyl polyoxyethylene ether, methallyl polyoxyethylene ether, allyl polyoxyethylene ether, or vinylhydroxybutyl polyoxyethylene ether, and the like, and the average addition number of the unsaturated polyoxyethylene ether is 10 to 100. The unsaturated carboxylic acid or the salt thereof is selected from one or more of methacrylic acid, acrylic acid and maleic anhydride. The unsaturated carboxylic acid ester is selected from one or more of hydroxyethyl acrylate, hydroxypropyl acrylate, methyl methacrylate, hydroxyethyl methacrylate and hydroxypropyl methacrylate. The initiator is selected from one or more of azobisisobutyronitrile, azobisisoheptonitrile, dimethyl azobisisobutyrate, benzoyl peroxide, sodium persulfate, ammonium persulfate, potassium persulfate and azobisisobutyramidine hydrochloride. The chain transfer agent is selected from one or more of 3-mercaptopropionic acid, thioglycolic acid, mercaptoethanol, sodium hypophosphite and sodium bisulfite. The polymerization inhibitor is selected from one or more of 2, 6-di-tert-butyl-4-methylphenol (BHT), p-benzoquinone, hydroquinone and phenothiazine.

In some embodiments, the temperature reached after the temperature rise and heating is 65-85 ℃, and the subsequent process for preparing the solid polycarboxylic acid slump retaining agent is carried out at the temperature of 65-85 ℃. The stirring time is 5-60 min, preferably 10 min. The dropping time is 1-10 hours, preferably 1 hour. The aging treatment time is 1-10 hours, preferably 2 hours.

The following is illustrated by specific examples: