Mud-resistant polycarboxylate superplasticizer and preparation method thereof

Abstract

The invention discloses an anti-mud polycarboxylic acid water reducer and a preparation method thereof, the anti-mud polycarboxylic acid water reducer comprises the following raw materials by weight: 300-350 parts of ethylene glycol monovinyl polyethylene glycol ether, 20-45 parts of acrylic acid, 10-30 parts of maleic anhydride, 10-30 parts of sodium hypophosphite, 10-30 parts of a chain transfer agent, 10-30 parts of an initiator, 10-30 parts of a neutralizer, 10-30 parts of an anti-mud sacrificial agent and 10-30 parts of water. The anti-mud anti-corrosion coating is prepared from the following components in parts by weight: 40 to 70 parts of maleic anhydride, 10 to 30 parts of sodium hypophosphite, 20 to 40 parts of chain transfer agent, 10 to 20 parts of initiator, 20 to 30 parts of neutralizer, 5 to 10 parts of anti-mud sacrificial agent and 340 to 495 parts of water. The composite water reducing agent has large steric hindrance, intercalation adsorption of the composite water reducing agent in soil can be reduced, the soil resistance is enhanced, and the slump of the composite water reducing agent is increased; the anti-mud sacrificial agent is introduced, so that the water-reducing rate of the polycarboxylate superplasticizer is increased, and effective components of the polycarboxylate superplasticizer are fully reacted; the preparation process is simple, environment-friendly and easy for industrial production.

Description

Technical Field

[0001] The invention relates to an anti-mud type polycarboxylate water reducer and a preparation method thereof. Background Art

[0002] Concrete is the most important material in modern construction and is widely used in the infrastructure industry. Concrete is composed of cement, mineral fine powder admixtures, sand and gravel aggregates, admixtures and water. Water reducers are commonly used admixtures in concrete. They can greatly improve the working capacity of concrete with less water, thereby improving the strength of concrete. The emergence of polycarboxylic acid water reducers has brought about a leap forward in the water reducer industry and even the entire cement field. Polycarboxylic acid water reducers have an irreplaceable position in modern building materials due to their low dosage, good dispersibility, high water reduction rate, green environmental protection, molecular controllable, and no wastewater and waste gas in the production process.

[0003] As a large amount of high-quality sand and gravel aggregates are consumed, some raw materials with high mud content, such as machine-made sand and construction waste aggregates, are gradually used in concrete projects. On the one hand, mud will compete with cement molecules to absorb a large number of polycarboxylic acid molecules, and on the other hand, the side chains composed of polyether in the polycarboxylic acid molecules are easily embedded in the aluminum silicate layer in the mud, thereby greatly reducing its original dispersion performance. In view of this, it is necessary to develop an anti-mud polycarboxylic acid water reducer. Summary of the invention

[0004] The main technical problem solved by the present invention is to provide an anti-mud type polycarboxylate water reducer and a preparation method thereof, which has a large steric hindrance, can reduce its intercalation adsorption in the soil, enhance the anti-mud performance, and increase the slump of the composite water reducer; by introducing an anti-mud sacrificial agent, the water reduction rate of the polycarboxylate water reducer is improved, so that its effective ingredients are fully reacted; the production process is simple, green and environmentally friendly, and easy to industrialize.

[0005] In order to solve the above technical problems, a technical solution adopted by the present invention is: to provide an anti-mud type polycarboxylate water reducer, the raw materials include: ethylene glycol monovinyl polyethylene glycol ether, acrylic acid, maleic anhydride, sodium hypophosphite, chain transfer agent, initiator, neutralizer, anti-mud sacrificial agent and water, and the raw materials are calculated by weight:

[0006]

[0007] In a preferred embodiment of the present invention, the chain transfer agent is at least one of sodium bisulfite, mercaptoethanol or isopropanol.

[0008] In a preferred embodiment of the present invention, the initiator is at least one of azobiscyclohexylcarbonitrile, azobisisoheptanenitrile or persulfate.

[0009] In a preferred embodiment of the present invention, the neutralizing agent is 30% sodium hydroxide solution.

[0010] In a preferred embodiment of the present invention, the anti-mud sacrificial agent is polyethylene glycol.

[0011] A method for preparing an anti-mud polycarboxylate water-reducing agent comprises the following steps:

[0012] S1: Ethylene glycol monovinyl polyglycol ether is mixed with water in a reactor and stirred to dissolve under the protection of nitrogen atmosphere, and then maleic anhydride and sodium hypophosphite are added, and the temperature is increased, and then acrylic acid, initiator and chain transfer agent are added dropwise with a peristaltic pump respectively, and then the temperature is kept, and finally after the reactant is cooled, the pH is adjusted to neutral with a neutralizer to obtain an anti-mud polycarboxylic acid water reducer;

[0013] S2: Mix the anti-mud polycarboxylate water-reducing agent and the anti-mud sacrificial agent in proportion and keep them warm at a specified temperature. Then cool them to obtain the anti-mud polycarboxylate water-reducing agent.

[0014] In a preferred embodiment of the present invention, in step S1, the initiator is ammonium persulfate solution, and the chain transfer agent is mercaptoethanol.

[0015] In a preferred embodiment of the present invention, in step S1, the heating temperature is 60-90°C and the insulation time is 4-8h.

[0016] In a preferred embodiment of the present invention, in step S2, the temperature is kept at 60-80°C for 3-6 hours.

[0017] The beneficial effects of the present invention are as follows: the anti-mud type polycarboxylate water-reducing agent and the preparation method thereof disclosed in the present invention have large steric hindrance, can reduce its intercalation adsorption in soil, enhance its anti-mud performance, and increase the slump of the composite water-reducing agent; by introducing an anti-mud sacrificial agent, the water reduction rate of the polycarboxylate water-reducing agent is improved, so that its effective ingredients are fully reacted; the production process is simple, green and environmentally friendly, and easy to industrialize. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] The embodiments of the present invention include:

[0020] The invention discloses an anti-mud type polycarboxylate water-reducing agent. The raw materials include: ethylene glycol monovinyl polyethylene glycol ether, acrylic acid, maleic anhydride, sodium hypophosphite, chain transfer agent, initiator, neutralizer, anti-mud sacrificial agent and water. The raw materials are calculated by weight as follows: 300-350 parts of ethylene glycol monovinyl polyethylene glycol ether, 20-45 parts of acrylic acid, 40-70 parts of maleic anhydride, 10-30 parts of sodium hypophosphite, 20-40 parts of chain transfer agent, 10-20 parts of initiator, 20-30 parts of neutralizer, 5-10 parts of anti-mud sacrificial agent and 340-495 parts of water.

[0021] Wherein, the chain transfer agent is at least one of sodium bisulfite, mercaptoethanol or isopropanol, the initiator is at least one of azobiscyclohexylcarbonitrile, azobisisoheptanenitrile or persulfate, the neutralizer is 30% sodium hydroxide solution, and the anti-mud sacrificial agent is polyethylene glycol.

[0022] A method for preparing an anti-mud polycarboxylate water-reducing agent comprises the following steps:

[0023] Ethylene glycol monovinyl polyethylene glycol ether is mixed with water in a reaction kettle and stirred to dissolve under the protection of nitrogen atmosphere, and then maleic anhydride and sodium hypophosphite are added, and the temperature is raised to 60-90°C, and then acrylic acid, ammonium persulfate solution and mercaptoethanol are respectively added dropwise with a peristaltic pump, and then the temperature is kept for 4-8 hours, and finally after the reactant is cooled, the pH is adjusted to neutral with a 30% sodium hydroxide solution to obtain an anti-mud polycarboxylic acid water reducer; the anti-mud polycarboxylic acid water reducer and the anti-mud sacrificial agent are evenly mixed in proportion, kept at 60-80°C for 3-6 hours, and cooled to obtain an anti-mud type polycarboxylic acid water reducer.

[0024] Embodiment 1

[0025] 350 parts of ethylene glycol monovinyl polyethylene glycol ether and 400 parts of water are mixed in a reactor and stirred to dissolve under the protection of a nitrogen atmosphere, and then 40 parts of maleic anhydride and 10 parts of sodium hypophosphite are added, and the temperature is raised to 80°C. Then, 4 parts of acrylic acid, 15 parts of ammonium persulfate solution and 30 parts of mercaptoethanol are respectively added dropwise with a peristaltic pump, and then kept warm for 4 hours. Finally, after the reactants are cooled, the pH is adjusted to neutral with a 30% sodium hydroxide solution to obtain an anti-mud polycarboxylic acid water reducer; 100 parts of anti-mud polycarboxylic acid water reducer and 5 parts of anti-mud sacrificial agent are mixed evenly in proportion, kept warm at 70°C for 4 hours, and cooled to obtain an anti-mud type polycarboxylic acid water reducer.

[0026] Embodiment 2

[0027] 350 parts of ethylene glycol monovinyl polyethylene glycol ether and 400 parts of water are mixed in a reactor and stirred to dissolve under the protection of a nitrogen atmosphere, and then 40 parts of maleic anhydride and 20 parts of sodium hypophosphite are added, and the temperature is raised to 80°C. Then, 4 parts of acrylic acid, 15 parts of ammonium persulfate solution and 30 parts of mercaptoethanol are respectively added dropwise with a peristaltic pump, and then kept warm for 4 hours. Finally, after the reactants are cooled, the pH is adjusted to neutral with a 30% sodium hydroxide solution to obtain an anti-mud polycarboxylic acid water reducer; 100 parts of anti-mud polycarboxylic acid water reducer and 5 parts of anti-mud sacrificial agent are mixed evenly in proportion, kept warm at 70°C for 4 hours, and cooled to obtain an anti-mud type polycarboxylic acid water reducer.

[0028] Embodiment 3

[0029] 350 parts of ethylene glycol monovinyl polyethylene glycol ether and 400 parts of water are mixed in a reactor and stirred to dissolve under the protection of a nitrogen atmosphere, and then 40 parts of maleic anhydride and 30 parts of sodium hypophosphite are added, and the temperature is raised to 80°C. Then, 4 parts of acrylic acid, 15 parts of ammonium persulfate solution and 30 parts of mercaptoethanol are respectively added dropwise with a peristaltic pump, and then kept warm for 4 hours. Finally, after the reactants are cooled, the pH is adjusted to neutral with a 30% sodium hydroxide solution to obtain an anti-mud polycarboxylic acid water reducer; 100 parts of anti-mud polycarboxylic acid water reducer and 5 parts of anti-mud sacrificial agent are mixed evenly in proportion, kept warm at 70°C for 4 hours, and cooled to obtain an anti-mud type polycarboxylic acid water reducer.

[0030] Embodiment 4

[0031] 350 parts of ethylene glycol monovinyl polyethylene glycol ether and 400 parts of water are mixed in a reactor and stirred to dissolve under the protection of a nitrogen atmosphere, and then 40 parts of maleic anhydride and 10 parts of sodium hypophosphite are added, and the temperature is raised to 80°C. Then, 4 parts of acrylic acid, 15 parts of ammonium persulfate solution and 30 parts of mercaptoethanol are respectively added dropwise with a peristaltic pump, and then kept warm for 4 hours. Finally, after the reactants are cooled, the pH is adjusted to neutral with a 30% sodium hydroxide solution to obtain an anti-mud polycarboxylic acid water reducer; 100 parts of anti-mud polycarboxylic acid water reducer and 10 parts of anti-mud sacrificial agent are mixed evenly in proportion, kept warm at 70°C for 4 hours, and cooled to obtain an anti-mud type polycarboxylic acid water reducer.

[0032] Embodiment 5

[0033] 350 parts of ethylene glycol monovinyl polyethylene glycol ether and 400 parts of water are mixed in a reactor and stirred to dissolve under the protection of a nitrogen atmosphere, and then 40 parts of maleic anhydride and 20 parts of sodium hypophosphite are added, and the temperature is raised to 80°C. Then, 4 parts of acrylic acid, 15 parts of ammonium persulfate solution and 30 parts of mercaptoethanol are respectively added dropwise with a peristaltic pump, and then kept warm for 4 hours. Finally, after the reactants are cooled, the pH is adjusted to neutral with a 30% sodium hydroxide solution to obtain an anti-mud polycarboxylic acid water reducer; 100 parts of anti-mud polycarboxylic acid water reducer and 10 parts of anti-mud sacrificial agent are mixed evenly in proportion, kept warm at 70°C for 4 hours, and cooled to obtain an anti-mud type polycarboxylic acid water reducer.

[0034] Embodiment 6

[0035] 350 parts of ethylene glycol monovinyl polyethylene glycol ether and 400 parts of water are mixed in a reactor and stirred to dissolve under the protection of a nitrogen atmosphere, and then 40 parts of maleic anhydride and 30 parts of sodium hypophosphite are added, and the temperature is raised to 80°C. Then, 4 parts of acrylic acid, 15 parts of ammonium persulfate solution and 30 parts of mercaptoethanol are respectively added dropwise with a peristaltic pump, and then kept warm for 4 hours. Finally, after the reactants are cooled, the pH is adjusted to neutral with a 30% sodium hydroxide solution to obtain an anti-mud polycarboxylic acid water reducer; 100 parts of anti-mud polycarboxylic acid water reducer and 10 parts of anti-mud sacrificial agent are mixed evenly in proportion, kept warm at 70°C for 4 hours, and cooled to obtain an anti-mud type polycarboxylic acid water reducer.

[0036] Comparative Example 1: Anti-mud polycarboxylic acid water-reducing agent (commercially available, model: Point-BT).

[0037] The anti-mud polycarboxylate water-reducing agent prepared in the present invention and comparative example 1 were tested for fluidity, water reduction rate and slump of mud-containing slurry.

[0038] 1. Test of fluidity of mud-containing slurry. Test the fluidity of cement slurry containing different amounts of PCEs according to the national standard GB / T8077-2012. 300g cement and 6g montmorillonite were placed in a cement slurry mixing pot, and mixing water mixed with PCEs was added, with a water-cement ratio (w / c) of 0.29. Use a cement slurry mixer (NJ-160A) to stir, first stir at a low speed for 120s, pause for 15s, and scrape the cement slurry on the blades and the pot wall into the pot, then stir at a high speed for 120s and stop. Pour the stirred cement slurry into a truncated cone (60mm high, 36mm top diameter, 60mm bottom diameter) placed on a horizontal glass plate. Lift the truncated cone vertically from the glass plate, measure the diameters in any two vertical directions when the cement slurry diffuses on the glass plate for 30s, and take the average value as the fluidity of the cement slurry containing mud.

[0039] 2. Water reduction rate test The water reduction rate of the water reducer was tested according to the national standard GB8076-2008 "Concrete Admixtures", and the water reduction rate of the water reducer was fixed at 0.12wt%. The mixing water volume was adjusted to control the initial slump of the concrete at 210±720mm. The concrete water reduction rate WR (%) of the composite polycarboxylic acid anti-mud water reducer was calculated by the following formula:

[0040] WR=(W0-W1) / W0×100%,

[0041] Where, W0: water consumption of blank concrete without water reducing agent (g); W1: water consumption of concrete with water reducing agent (g);

[0042] The slump test is carried out according to the national standard GB / T50080-2016 to test the slump of water-reducing agent dispersed concrete. Specific method: Concrete base mix ratio (kg / m 3 ) is: m(cement): m(sand): m(stone) = 360:760:1050. Stir the concrete mixture mixed with water reducer evenly, put it into the slump test bucket several times and tamp it. Lift the test bucket vertically upward, and the concrete will begin to collapse freely due to its own gravity. When the slump is stable, measure the height and expansion diameter of the concrete mixture. The difference between the bucket height and the highest point height of the concrete mixture is the slump, in mm.

[0043] As shown in Table 1 below, the test results of the embodiment of the anti-mud polycarboxylate water-reducing agent and the comparative example 1 are compared:

[0044]

[0045] As can be seen from Table 1, the anti-mud polycarboxylate water-reducing agent prepared in the present invention has good anti-mud performance, good fluidity in mud-containing slurry, high water reduction rate, and good slump in concrete. In particular, Example 4 has better mud-containing slurry fluidity, water reduction rate and slump than other examples.

[0046] In summary, the anti-mud polycarboxylate water-reducing agent and the preparation method thereof disclosed in the present invention have large steric hindrance, can reduce its intercalation adsorption in soil, enhance its anti-mud performance, and increase the slump of the composite water-reducing agent; by introducing an anti-mud sacrificial agent, the water reduction rate of the polycarboxylate water-reducing agent is improved, so that its effective ingredients are fully reacted; the production process is simple, green and environmentally friendly, and easy to industrialize.

[0047] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. An anti-mud type polycarboxylate water reducer, characterized in that: Ingredients include: Ethylene glycol monovinyl polyglycol ether, acrylic acid, maleic anhydride, sodium hypophosphite, chain transfer agent, initiator, neutralizer, anti-mud sacrificial agent and water, each raw material is calculated by weight: Ethylene glycol monovinyl polyglycol ether 300-350 parts Acrylic acid 20-45 parts Maleic anhydride 40-70 parts 10-30 parts of sodium hypophosphite Chain transfer agent 20-40 parts Initiator 10-20 parts Neutralizer 20-30 parts Anti-mud sacrificial agent 5-10 parts 340-495 parts of water.

2. The anti-mud type polycarboxylate water reducer according to claim 1, characterized in that: The chain transfer agent is at least one of sodium bisulfite, mercaptoethanol or isopropanol.

3. The anti-mud type polycarboxylate water reducer according to claim 1, characterized in that: The initiator is at least one of azobiscyclohexylcarbonitrile, azobisisoheptanenitrile or persulfate.

4. The anti-mud type polycarboxylate water reducer according to claim 1, characterized in that: The neutralizing agent is 30% sodium hydroxide solution.

5. The anti-mud type polycarboxylate water reducer according to claim 1, characterized in that: The anti-mud sacrificial agent is polyethylene glycol.

6. A method for preparing the anti-mud polycarboxylate water-reducing agent according to any one of claims 1 to 5, characterized in that: The steps include: S1: Ethylene glycol monovinyl polyglycol ether is mixed with water in a reactor and stirred to dissolve under the protection of nitrogen atmosphere, and then maleic anhydride and sodium hypophosphite are added, and the temperature is increased, and then acrylic acid, initiator and chain transfer agent are added dropwise with a peristaltic pump respectively, and then the temperature is kept, and finally after the reactant is cooled, the pH is adjusted to neutral with a neutralizer to obtain an anti-mud polycarboxylic acid water reducer; S2: Mix the anti-mud polycarboxylate water-reducing agent and the anti-mud sacrificial agent in proportion and keep them warm at a specified temperature. Then cool them to obtain the anti-mud polycarboxylate water-reducing agent.

7. The method for preparing the anti-mud type polycarboxylate water reducer according to claim 6, characterized in that: In step S1, the initiator is ammonium persulfate solution, and the chain transfer agent is mercaptoethanol.

8. A method for preparing the anti-mud type polycarboxylate water-reducing agent according to claim 6, characterized in that: In step S1, the heating temperature is 60-90°C and the insulation time is 4-8h.

9. A method for preparing the anti-mud type polycarboxylate water-reducing agent according to claim 6, characterized in that: In step S2, the temperature is kept at 60-80°C for 3-6 hours.

Images