DE112020007177T5 - Solid polycarboxylic acid superplasticizer and method of making same - Google Patents

Abstract

The present invention provides a solid polycarboxylic acid flow agent and a method for its manufacture. The manufacturing process includes: melting a polyether polyol monomer and a highly branched monomer into a liquid; adding an initiator to the liquid, stirring, and then adding an unsaturated carboxylic acid and a chain transfer agent to obtain a mixed solution; and subjecting the mixed solution to an aging treatment and then cooling and solidifying to obtain the polycarboxylic acid solid flow agent. According to the solid polycarboxylic acid superplasticizer in the present invention, the highly branched monomer is added, so that the viscosity requirements during polymerization are reduced, the workability of the concrete in the concrete evaluation process is better, there are no phenomena such as bleeding, mortar bleeding and stone oozing and under under the condition of low water-cement ratio, the viscosity of the concrete can be reduced. In addition, according to the process of the present invention, the anhydrous solid polycarboxylic acid superplasticizer can be recovered after completion of the preparation. In contrast to the conventional flux in stock solution, a powdered polycarboxylic acid flux can be obtained by spray drying. Compared with the powdery polycarboxylic acid superplasticizer, the solid polycarboxylic acid superplasticizer greatly reduces the production cost and long-distance transportation cost.

Description

technical field

The invention relates to the field of concrete additives, in particular to a solid polycarboxylic acid superplasticizer and its production process.

Technological background

Superplasticizers are an indispensable and important component in today's concrete industry. From the first generation of ordinary lignosulfonate-based superplasticizers, through the second generation of naphthalene-based, melamine-based, aminosulfonate-based, fatty acid-based and other high-performance superplasticizers, to the current third-generation polycarboxylic acid-based superplasticizer, each superplasticizer has its own unique advantages; in particular, the high-performance plasticizer based on polycarboxylic acid is the most widely used plasticizer in concrete today and has already been used in various large-scale projects.

However, most polycarboxylic acid-based superplasticizers on the market are mainly based on the use of mother liquor, and the solid content of the product is usually about 40-50%, which increases the cost of transportation and limits its application in construction such as shotcrete and dry mortar. Although it is now possible to convert the superplasticizer mother liquor directly into powdered polycarboxylic acid by spray drying, spray drying has high energy consumption, product losses during drying, and safety problems in production.

CN108192041A discloses a production process and application of a powdery polycarboxylic acid flow agent, the production of the benzene ring-containing polycarboxylic acid flow agent, and the process for the production of a powdery polycarboxylic acid flow agent after spray drying and the use thereof. The production process comprises: preparing the mother liquor of the polycarboxylic acid superplasticizer by radical copolymerization of carboxylic acid monomer a, benzene ring-containing small monomer b and benzene ring-containing polyether monomer c in an aqueous medium; directly passing the mother liquor of the polycarboxylic acid superplasticizer through the centrifugal atomizer of the atomizer to form droplets without adding an insulating agent, controlling the average particle size of the powder to 50-150 µm and drying the droplets after entering the drying chamber; and the material is fed to the discharge port by the induced draft fan, and the material is packed and discharged by a bag packing machine to obtain a powdery polycarboxylic acid flow agent. The invention has certain losses in the process of spray centrifugation, and spray drying requires high temperature and high energy consumption with the same performance.

CN108484841A discloses a process for preparing a solid flaky polycarboxylic acid flow agent by bulk polymerization. A solid flaky polycarboxylic acid flow agent produced by bulk polymerization, the production process comprising: adding a specified amount of a freshly synthesized liquid polyether monomer and a viscosity reducing agent to a reaction vessel, stirring and heating; setting the temperature to 100-105 °C; adding a specified amount of an initial initiator, an organic peroxide initiator, a solubilizer, a chain transfer agent and an initial initiator; dropwise addition of a solution of a small monomer for one hour. The small monomer solution consists of a fluorinated functional monomer and acrylic acid in a specific ratio. After 10 minutes of adding the small monomer solution dropwise, a certain amount of organic peroxide initiator is added to the kettle, and then every 10 minutes until the last addition of the small monomer solution is completed; after the addition, the temperature is raised to 110-115°C, keeping the temperature constant, aging for b hours, and then the flakes are cooled for packaging to obtain a solid flaky polycarboxylic acid flow agent. The method of the invention in the synthesis is relatively complex, and the reaction temperature is high, causing a large loss in energy consumption.

It should be noted that the information disclosed in the background technology is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not belong to the well-known prior art.

Summary of the Invention

The aim of the present invention is to overcome the deficiencies of the prior art and to provide a solid polycarboxylic acid superplasticizer with good processability and low production and transportation costs.

• ein Verfahren zur Herstellung eines festen Polycarbonsäure-Fließmittels, umfassend:
  • Schmelzen eines Polyether-Monomers und eines hochverzweigten Monomers zu einer Flüssigkeit;
  • Zugabe eines Initiators zu der Flüssigkeit, Rühren und anschließende Zugabe einer ungesättigten Carbonsäure und eines Kettenübertragungsmittels, um eine gemischte Lösung zu erhalten; und
  • die gemischte Lösung einer Alterungsbehandlung zu unterziehen und anschließend abzukühlen und zu verfestigen, um das feste Polycarbonsäure-Fließmittel zu erhalten.

In order to achieve the above objective, the following technical solutions are applied in the present invention:

• a process for preparing a solid polycarboxylic acid flow agent comprising:
  • melting a polyether monomer and a highly branched monomer into a liquid;
  • adding an initiator to the liquid, stirring, and then adding an unsaturated carboxylic acid and a chain transfer agent to obtain a mixed solution; and
  • to subject the mixed solution to an aging treatment, and then to cool and solidify it to obtain the polycarboxylic acid solid superplasticizer.

In some embodiments, based on the total mass of each raw material, the addition amount of the polyether monomer is 82-89%, the addition amount of the hyperbranched monomer is 0.4-3%, the addition amount of the unsaturated carboxylic acid is 7-11%, the addition amount of the chain transfer agent is 0, 2-0.7% and the addition amount of the initiator 0.4-1.5%.

In some embodiments, the polyether monomer is selected from one or more of methallyl polyoxyethylene ether, isopentenol polyoxyethylene ether, and hydroxybutyl polyoxyethylene ether, and the molecular weight of the polyether monomer is 1200-5000, preferably 2000-4000.

In some embodiments, the hyperbranched monomer has a structure represented by formula I where n is an integer from 1-15, m is an integer from 1-10, x is an integer from 1-10, and y is an integer from 1-10,

In some embodiments, the initiators are selected from one or more of the following: benzoyl peroxide, dodecanoyl peroxide, ammonium persulfate, potassium persulfate, sodium persulfate, azodiisobutyronitrile, azodiisoheptanenitrile, azodiisovaleronitrile, azodicyclohexylcarbonitrile, dimethyl 2,2'-azobis(2-methylpropionate), dicyclohexyl peroxydicarbonate, and dicetyl peroxydicarbonate .

In some embodiments, the unsaturated carboxylic acid is selected from one or more of the following acids: acrylic acid, methacrylic acid, itaconic acid, maleic anhydride, maleic acid, and fumaric acid.

In some embodiments, the chain transfer agent is selected from one or more of the following: sodium methacrylate sulfonate, sodium allylate sulfonate, mercaptoacetic acid, mercaptopropionic acid, mercaptoethanol, n-dodecyl mercaptan, sodium hypophosphite, sodium vinyl sulfonate, sodium propenyl sulfonate, and sodium styrene sulfonate.

In some embodiments, the unsaturated carboxylic acid and chain transfer agent are added to the liquid dropwise and the drop time is 0.5-2 hours.

In some embodiments, the duration of the aging treatment is 0.5-3 hours.

In another aspect, the present invention provides a polycarboxylic acid solid flow agent made by the process described above.

The polycarboxylic acid solid superplasticizer of the present invention has reduced viscosity requirements during polymerization due to the addition of highly branched monomers, and has good workability on concrete in the concrete evaluation process, and has no phenomena such as bleeding, mortar bleeding and stone exudation. and under the condition of low water-cement ratio, concrete viscosity is reduced. Furthermore, according to the process of the present invention, the anhydrous solid polycarboxylic acid flow agent product can be obtained after the completion of the preparation. Unlike the conventional water solvent, a powdered polycarboxylic acid superplasticizer can only be obtained after spray drying. Compared with the powdery polycarboxylic acid superplasticizer, the solid polycarboxylic acid superplasticizer greatly reduces the production cost and long-distance transportation cost.

Detailed Description of Preferred Embodiments

The technical solution of the present invention is described below by means of the specific embodiments, which are only illustrative and do not limit the present invention in any way.

• Schmelzen eines Polyether-Monomers und eines hochverzweigten Monomers zu einer Flüssigkeit;
• Zugabe eines Initiators zu der Flüssigkeit, Rühren und anschließende Zugabe einer ungesättigten Carbonsäure und eines Kettenübertragungsmittels, um eine gemischte Lösung zu erhalten; und
• die gemischte Lösung einer Alterungsbehandlung zu unterziehen und anschließend abzukühlen und zu verfestigen, um das feste Polycarbonsäure-Fließmittel zu erhalten.

The present invention provides a process for preparing a solid polycarboxylic acid flow agent, comprising the following steps:

• melting a polyether monomer and a highly branched monomer into a liquid;
• adding an initiator to the liquid, stirring, and then adding an unsaturated carboxylic acid and a chain transfer agent to obtain a mixed solution; and
• to subject the mixed solution to an aging treatment, and then to cool and solidify it to obtain the polycarboxylic acid solid superplasticizer.

Based on the total mass of each raw material, the addition amount of polyether monomer is 82-89%, the addition amount of hyperbranched monomer is 0.4-3%, the addition amount of unsaturated carboxylic acid is 7-11%, the addition amount of chain transfer agent is 0.2-0.7% % and the addition amount of the initiator 0.4-1.5%.

The polyether monomer and the hyperbranched monomer are first melted into a liquid at a specific temperature range. The polyether monomer can be fully melted first, followed by addition of the hyperbranched monomer to melt. The melting temperature can be adjusted to 65-100 °C.

The polyether monomer is selected from one or more of methallyl polyoxyethylene ether, isopentenol polyoxyethylene ether and hydroxybutyl polyoxyethylene ether, and the molecular weight of the polyether monomer is 1200-5000, preferably 2000-4000.

The hyperbranched monomer used in the invention is a polymer obtained by randomly blocking ethylene oxide and propylene oxide with polyethylene polyamine (as a raw material) having a structure represented by the formula I, where n is the addition number of ethylene oxide (EO) is an integer from 1-15, preferably an integer from 3-10, and m represents the addition number of propylene oxide (PO) which is an integer from 1-10, preferably an integer is a number from 2-6, x is an integer from 1-10 and y is an integer from 1-10,

After both the polyether monomer and the hyperbranched monomer are melted into a liquid, an initiator is added to the liquid and stirred. The initiator used in the present invention is an oil-soluble initiator selected from one or more of the following: benzoyl peroxide, dodecanoyl peroxide, ammonium persulfate, potassium persulfate, sodium persulfate, azodiisobutyronitrile, azodiisoheptanenitrile, azodiisovaleronitrile, azodicyclohexylcarbonitrile, dimethyl-2,2'-azobis( 2-methylpropionate), dicyclohexyl peroxydicarbonate and dicetyl peroxydicarbonate. The stirring time is usually 5-10 minutes.

After adding and stirring the initiator, unsaturated carboxylic acid and chain transfer agent are added to the liquid. The unsaturated carboxylic acid and chain transfer agent can be mixed first and then added simultaneously. The addition is preferably done dropwise and the dropping time is 0.5-2 hours.

The unsaturated carboxylic acid used in the invention is selected from one or more of the following acids: acrylic acid, methacrylic acid, itaconic acid, maleic anhydride, maleic acid and fumaric acid.

The chain transfer agent used in the invention is selected from one or more of the following: sodium methacrylate sulfonate, sodium allylate sulfonate, mercaptoacetic acid, mercaptopropionic acid, mercaptoethanol, n-dodecyl mercaptan, sodium hypophosphite, sodium vinyl sulfonate, sodium propenyl sulfonate and sodium styrene sulfonate.

After adding the unsaturated carboxylic acid and the chain transfer agent, a mixed solution is obtained, which is subjected to an aging treatment at a certain constant temperature with constant stirring; the duration of the aging treatment is 0.5-3 hours.

After the aging treatment, the temperature is lowered to about 60°C and the material is discharged, and the anhydrous solid polycarboxylic acid superplasticizer can be recovered after the product is solidified at room temperature.

The polycarboxylic acid solid superplasticizer prepared by the present invention can be processed into liquids of various concentrations by adding water, or further processed into a powdery polycarboxylic acid solid superplasticizer according to different construction requirements. Powdered solid polycarboxylic acid superplasticizer can be used directly by mixing into dry mortar or shotcrete. The process of morphological change does not affect the initial performance of the superplasticizer.

The polycarboxylic acid solid flow agent of the present invention has reduced viscosity requirements during polymerization due to the addition of highly branched monomers. The polycarboxylic acid solid flow agent of the present invention is stable and adhesion does not occur when stored at room temperature. The polycarboxylic acid solid superplasticizer of the present invention has excellent water-reducing and dispersing effects, good concrete workability in concrete evaluation, and has no phenomena such as bleeding, mortar bleeding, stone exudation, etc. It still has good flowability and retention ability under low mixing amount, and can keep good workability under different mixing amount, and has strong adaptability to different kinds of cement.

In addition, with the production method of the present invention, anhydrous solid polycarboxylic acid superplasticizer products can be obtained directly, and a powdery polycarboxylic acid superplasticizer can be obtained without subjecting it to spray drying, as is the case with conventional mother liquor water agents. Compared with the mother liquor of traditional polycarboxylic acid superplasticizer, the production process and production cycle are simple and short, and the operation is more convenient. The product has obvious advantages in terms of transportation distance and transportation cost. If polyether thermal materials can be used to produce solid polycarboxylic acid superplasticizer, the total cost can be reduced by about 30%, which means significant energy savings and consumption reduction for superplasticizer manufacturers.

Therefore, the whole process of the preparation method of the present invention is green and environmentally friendly, which is conducive to industrial production and industrial promotion and application, and has good economic benefits and social significance.

The present invention is explained in more detail below with reference to specific examples. These examples describe preferred embodiments but do not constitute limitations of the invention. Anyone skilled in the art can change them to the equivalent embodiment using the invention described above.

examples

Example of Preparation - Synthesis of a Hyperbranched Monomer

In a dry 0.3 liter stainless steel high pressure reaction kettle, 40 g of polyethylene polyamine and 0.2 g of catalyst were added. The reaction vessel was closed and nitrogen replacement was injected three times, heated to 120°C, 29.34g of ethylene oxide and 23.2g of propylene oxide were slowly added to the reaction vessel, the reaction temperature was maintained at 120-130°C, under 0 pressure .3-0.4MPa during feeding. After completion of the feeding, mixing was continued at 120°C for 1 hour and then cooled to 75-80°C to obtain the hyperbranched monomer.

example 1

First, 350 g of methallylpolyoxyethylene ether (theoretical molecular weight of 2400) was added to the reactor and heated to 70°C. After the material was completely melted, 3.5 g of the hyperbranched monomer from Preparation Example was added and stirred for 10 minutes, then 3.5 g of benzoyl peroxide was added as an initiator. After stirring for 10 minutes, a mixed solution of 37.5 g of acrylic acid and 2 g of mercaptoacetic acid was added dropwise. The drop reaction time was set to 1h ± 5min. After the reaction, the temperature was raised to 75°C to ripen for 2 hours. After maturation, the materials were poured into a bowl for disposal. After solidification of the product, an anhydrous solid polycarboxylic acid flow agent was obtained.

example 2

First, 357 g of methallylpolyoxyethylene ether (theoretical molecular weight of 3000) was added to the reactor and heated to 75°C. After the material was completely melted, 4 g of the hyperbranched monomer from the preparation example was added and stirred for 10 minutes, then 3.6 g of benzoyl peroxide was added as an initiator. After stirring for 10 minutes, a mixed solution of 37.9 g of acrylic acid and 2.2 g of sodium hypophosphite was added dropwise. The drop reaction time was set to 1h ± 5min. After the reaction, the material was aged for 2 hours. After maturation, the materials were poured into a bowl for disposal. After solidification of the product, an anhydrous solid polycarboxylic acid flow agent was obtained.

Example 3

First, 351 g of methallylpolyoxyethylene ether (theoretical molecular weight of 3000) was added to the reactor and heated to 75°C. After the material was completely melted, 5 g of the hyperbranched monomer from Preparation Example was added and stirred continuously for 10 minutes, then 4 g of azodiisobutyronitrile was added as an initiator. After stirring for 10 minutes, a mixed solution of 35.3 g of acrylic acid, 1.5 g of mercaptopropionic acid and 0.7 g of mercaptoethanol was dripped bit by bit admitted. The drop reaction time was set to 1h ± 5min. After the reaction, the product was aged for 2 hours. After maturation, the materials were poured into a bowl for disposal. After solidification of the product, an anhydrous solid polycarboxylic acid flow agent was obtained.

example 4

First, 345 g of isopentenol polyoxyethylene ether (theoretical molecular weight of 2400) was added to the reactor and heated to 75°C. After the material was completely melted, 5 g of the hyperbranched monomer from Preparation Example was added and stirred continuously for 10 minutes, then 4 g of azodiisobutyronitrile was added as an initiator. After stirring for 10 minutes, a mixed solution of 40.2 g of methacrylic acid and 2.3 g of sodium hypophosphite was added dropwise. Drop reaction time was set at 1.5 hours ± 5 minutes. After the reaction, the material was aged for 2.5 hours. After maturation, the materials were poured into a bowl for disposal. After solidification of the product, an anhydrous solid polycarboxylic acid flow agent was obtained.

Example 5

First, 326 g of isopentenol polyoxyethylene ether (theoretical molecular weight of 3000) was added to the reactor and heated to 70°C. After the material was completely melted, 6 g of the hyperbranched monomer from the Preparation Example was added and stirred continuously for 10 minutes, then 2 g of azodiisobutyronitrile and 2.5 g of azodiisovaleronitrile were added as an initiator. After stirring for 10 minutes, a mixed solution of 36.2 g of methacrylic acid and 2.3 g of sodium hypophosphite was added dropwise. Drop reaction time was set at 1.5 hours ± 5 minutes. After the reaction, the material was aged for 2.5 hours. After maturation, the materials were poured into a bowl for disposal. After solidification of the product, an anhydrous solid polycarboxylic acid flow agent was obtained.

Example 6

First, 364 g of hydroxybutyl polyoxyethylene ether (theoretical molecular weight of 2400) was added to the reactor and heated to 75°C. After the material was completely melted, 6 g of hyperbranched monomer 3 from Preparation Example was added and stirred for 10 minutes, then 3.8 g of ammonium persulfate was added as an initiator. After stirring for 10 minutes, a mixed solution of 30.9 g of methacrylic acid and 3 g of sodium methacrylate sulfonate was added dropwise. The drop reaction time was set to 1h ± 5min. After the reaction, the material was aged for 2.5 hours. After maturation, the materials were poured into a bowl for disposal. After solidification of the product, an anhydrous solid polycarboxylic acid flow agent was obtained.

Example 7

First, 350 g of hydroxybutyl polyoxyethylene ether (theoretical molecular weight of 3000) was added to the reactor and heated to 75°C. After the material was completely melted, 3 g of the hyperbranched monomer from the preparation example was added and stirred for 10 minutes, then 3.8 g of ammonium persulfate was added as an initiator. After stirring for 10 minutes, a mixed solution of 30.9 g of methacrylic acid and 3 g of sodium methacrylate sulfonate was added dropwise. The drop reaction time was set to 1h ± 5min. After the reaction, the material was aged for 2.5 hours. After maturation, the materials were poured into a bowl for disposal. After solidification of the product, an anhydrous solid polycarboxylic acid flow agent was obtained.

example 8

First, 342 g of hydroxybutylpolyoxyethylene ether (theoretical molecular weight of 3600) was added to the reactor and heated to 80°C. After the material was completely melted, 4 g of the hyperbranched monomer from the Preparation Example was added and stirred continuously for 10 minutes, then 3.5 g of azodiisobutyronitrile was added as an initiator. After stirring for 5 minutes, a mixed solution of 32.7 g of methacrylic acid, 7 g of itaconic acid, 1 g of mercaptopropionic acid and 0.7 g of mercaptoethanol was added dropwise. The drop reaction time was set to 1h ± 5min. After the reaction, the product was aged for 2 hours. After aging, the materials were converted into a Shell poured for disposal. After solidification of the product, an anhydrous solid polycarboxylic acid flow agent was obtained.

The solid polycarboxylic acid flow agent prepared in Examples 1-8 was placed in an oven to melt. The viscosity of the samples of Examples 1-8 and the viscosity of Comparative Examples 1-8 were determined with a viscometer at 70°C using a kinematic viscosity tester for petroleum products, except that in the Comparative Examples no hyperbranched monomers were used under the same conditions as were added in the examples. The molecular weight of the samples of Examples 1-8 and the molecular weight of the samples of Comparative Examples 1-8 (without hyperbranched monomer) were determined using gel liquid chromatography. The results are shown in Table 1. Table 1 Comparison of the viscosity and molecular weight of the polycarboxylic acid solid flow agent prepared in the examples with the comparative examples. PCE type With hyperbranched monomer / cps With hyperbranched monomer/ Mw PCE type Without hyperbranched monomer / cps Without hyperbranched monomer / Mw example 1 3445 44100 Comparative example 1 5230 45300 example 2 3310 39600 Comparative example 2 5510 40200 Example 3 3019 44300 Comparative example 3 5193 43500 example 4 3285 42700 Comparative example 4 5344 43300 Example 5 3356 45700 Comparative example 5 5713 45900 Example 6 3207 41500 Comparative example 6 4937 42800 Example 7 3412 48100 Comparative example 7 5218 47700 example 8 3350 42300 Comparative example 8 5078 43200

From the test, it is found that the viscosity of the samples with hyperbranched monomers is generally between 3000-3500 and that without hyperbranched monomers is generally between 4900-5500, and the molecular weight of the solid polycarboxylic acid flow agent products has not changed significantly. It has been proven that the addition of highly branched monomers has significantly reduced the viscosity of solid polycarboxylic acid superplasticizer, and the reduction in viscosity shows that the requirements of solid polycarboxylic acid superplasticizer on production equipment are reduced, which improves molding performance and cutting of the product, leaving more room for improving product profits.

The solid polycarboxylic acid flow agents prepared in Examples 1-8 were made into flow agents at a concentration of 10%. According to the test requirements for high-performance superplasticizers in GB8076-2008 Concrete Admixture, the performance of the samples synthesized in the examples was compared with that of the commercial superplasticizer (HD-14 High Performance Polycarboxylic Acid Superplasticizer manufactured by Shenyang Haida Building Materials Factory). The mix ratio for the test is given in Table 2 and the results of the concrete test are given in Table 3 and Table 4. Table 2. Mixing ratio for testing the concrete (kg / m ³ ) sand (medium sand) sand (fine sand) gravel (5-10cm) gravel (10-25cm) cement mineral powder fly ash Water mix amount 745 130 356 832 350 75 75 165 0.2% Table 3. Concrete performance test results for Qianshan concrete 42.5 No. PCE type Concrete settlement (mm) / expansion (mm) bleeding rate% Original 1 hour 1 Commercial flow agent 210/530*520 190/490*480 13 2 example 1 215/520*525 205/500*510 5 3 example 2 225/545*560 220/535*540 4 4 Example 3 245/600*590 240/590*580 2 5 example 4 210/535*250 205/510*515 5 6 Example 5 215/525*535 200/500*490 5 7 Example 6 235/560*570 225/530*540 5 8th Example 7 240/580*590 230/560*550 3 9 example 8 230/540*555 220/535*535 4 Table 4. Concrete Performance Test Results for Conch Cement 42.5 No. PCE type Concrete settlement (mm) / expansion (mm) bleeding rate% Originally 1 hour 1 Commercial flow agent 205/525*520 190/470*480 10 2 example 1 215/530*525 210/515*500 6 3 example 2 230/545*540 215/530*530 5 4 Example 3 250/600*610 240/575*570 3 5 example 4 215/535*525 205/500*500 6 6 Example 5 220/530*530 210/520*215 5 7 Example 6 230/560*550 220/535*540 5 8th Example 7 240/580*570 235/550*560 4 9 example 8 240/570*570 230/540*550 4

The above experimental results show that the solid polycarboxylic acid superplasticizer produced by the invention has good adaptability to various cement types, higher water reduction rate and better retention properties compared to the traditional polycarboxylic acid superplasticizer mother liquor. In addition, the addition of hyperbranched monomer in the present invention reduces the product viscosity and the bleeding rate of the concrete without obvious bleeding, mortar bleeding and stone oozing, and can improve the workability of the concrete to some extent.

It should be appreciated by those skilled in the art that the embodiments described in the present invention are merely exemplary and that various other alternatives, modifications and improvements are possible within the scope of the present invention. Therefore, the present invention is not limited to the above embodiments but is limited only by the set of claims.

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• CN 108192041A [0004]
• CN 108484841A [0005]
• GB80762008 [0047]

Claims (10)

A method of making a solid polycarboxylic acid flow agent comprising: melting a polyether monomer and a highly branched monomer into a liquid; adding an initiator to the liquid, stirring, and then adding an unsaturated carboxylic acid and a chain transfer agent to obtain a mixed solution; and to subject the mixed solution to an aging treatment, and then to cool and solidify it to obtain the polycarboxylic acid solid superplasticizer. procedure after claim 1 , wherein, based on the total mass of each raw material, the addition amount of the polyether monomer is 82-89%, the addition amount of the hyperbranched monomer is 0.4-3%, the addition amount of the unsaturated carboxylic acid is 7-11%, the addition amount of the chain transfer agent is 0, is 2-0.7% and the addition amount of the initiator is 0.4-1.5%. procedure after claim 1 wherein the polyether monomer is selected from one or more of methallyl polyoxyethylene ether, isopentenol polyoxyethylene ether and hydroxybutyl polyoxyethylene ether, and the molecular weight of the polyether monomer is 1200-5000, preferably 2000-4000. procedure after claim 1 wherein the hyperbranched monomer has a structure represented by the formula I wherein n is an integer of 1-15, m is an integer of 1-10, x is an integer of 1-10, and y is an integer of 1-10 is

procedure after claim 1 wherein the initiator is selected from one or more of benzoyl peroxide, dodecanoyl peroxide, ammonium persulfate, potassium persulfate, sodium persulfate, azodiisobutyronitrile, azodiisoheptanenitrile, azodiisovaleronitrile, azodicyclohexylcarbonitrile, dimethyl 2,2'-azobis(2-methylpropionate), dicyclohexyl peroxydicarbonate and dicetyl peroxydicarbonate. procedure after claim 1 wherein the unsaturated carboxylic acid is selected from one or more of acrylic acid, methacrylic acid, itaconic acid, maleic anhydride, maleic acid and fumaric acid. procedure after claim 1 wherein the chain transfer agent is selected from one or more of sodium methacrylate sulfonate, sodium allylate sulfonate, mercaptoacetic acid, mercaptopropionic acid, mercaptoethanol, n-dodecyl mercaptan, sodium hypophosphite, sodium vinyl sulfonate, sodium propenyl sulfonate and sodium styrene sulfonate. procedure after claim 1 , wherein the unsaturated carboxylic acid and the chain transfer agent are added dropwise to the liquid, and the dropping time is 0.5-2 hours. procedure after claim 1 , where the time for aging treatment is 0.5-3h. Solid polycarboxylic acid flow agent, wherein the solid polycarboxylic acid flow agent by the method according to any one of Claims 1 until 9 will be produced.