Nano calcium carbonate dispersion stabilizer, preparation method thereof and nano calcium carbonate dispersion liquid

Abstract

The invention relates to the field of concrete building materials, and provides a nano calcium carbonate dispersion stabilizer, a preparation method thereof and a nano calcium carbonate dispersion liquid. The nano calcium carbonate dispersion stabilizer is prepared from the following raw materials in parts by weight: 10 to 20 parts of triisopropanolamine, 80 to 90 parts of acrylic acid-acrylamide copolymer and 0.1 to 0.5 part of thickening resin. According to the nano calcium carbonate dispersion stabilizer, the triisopropanolamine, the acrylic acid-acrylamide copolymer and the thickening resin are combined and matched, so that the nano calcium carbonate dispersion stabilizer has a relatively high dispersion effect, has a particularly obvious dispersion effect on nano calcium carbonate, and can effectively prevent the nano calcium carbonate from being agglomerated.

Description

Technical Field

[0001] This invention relates to the field of concrete building materials, and particularly to a nano-calcium carbonate dispersion stabilizer. The invention also relates to a method for preparing the aforementioned nano-calcium carbonate dispersion stabilizer and a nano-calcium carbonate dispersion containing the aforementioned nano-calcium carbonate dispersion stabilizer. Background Technology

[0002] Nano-calcium carbonate refers to particles and aggregates (powders) with spatial dimensions in the nanometer range (1-100 nm). It is characterized by being non-toxic, odorless, having good filling properties, abundant resources, and low price. Its promising application prospects in concrete are mainly reflected in: (1) Nano-calcium carbonate has a micro-aggregate filling effect. Since the particle size is much smaller than that of cement particles, the small gaps between cement particles are filled, the particle size distribution of cementitious materials becomes more reasonable, and the density of microstructure increases.

[0003] (2) The nucleation effect of nano-calcium carbonate. On the one hand, the high surface energy allows Ca in the slurry to nucleate. 2+ and OH － Adsorbed on its surface, Ca(OH)₂ crystals first nucleate, reducing their orientation and improving enrichment and arrangement, thus promoting the hydration and growth of tricalcium silicate in the interfacial transition zone of concrete. On the other hand, its high specific surface area increases the contact area with water, further promoting tricalcium silicate hydration. CSH gel uses nano-calcium carbonate as growth points, lowering the nucleation barrier and forming bonds on its surface, gradually transforming from a flocculent structure into a well-defined, overlapping columnar network structure, filling harmful pores in the paste and improving the interfacial structure between cement paste and aggregate.

[0004] (3) Chemical activity of nano-calcium carbonate. During the hydration process, it reacts with tricalcium aluminate (3CaO·Al2O3, C3A) to produce hydrated calcium carboaluminate in high-carbonate or low-carbonate form, which promotes cement hydration and improves the strength after hardening.

[0005] (4) Improvement effect of the interface transition zone. The mechanical properties of cement-based materials are often affected by the weak area of ​​the interface. The incorporation of nano-calcium carbonate significantly improves the hydration products and uneven microstructure of the interface transition zone, reduces the porosity and number of cracks in the weak area, and thus achieves the optimization effect.

[0006] However, due to their high surface energy, nanoparticles are prone to aggregation. In practical applications, the particle size is often secondary, potentially exceeding the nanoscale. Aggregation prevents nanoparticles from fully realizing their advantages, posing significant challenges to their application. Therefore, improving the dispersion performance of nanoparticles is a prerequisite and foundation for their application. Furthermore, even if nano-calcium carbonate is temporarily dispersed through mechanical or other means, a certain period of dispersion is still required. If it re-aggregates after a certain time, it still limits its usability. Summary of the Invention

[0007] In view of this, the present invention proposes a nano-calcium carbonate dispersion stabilizer to prolong the viscosity-reducing effect time.

[0008] To achieve the above objectives, the technical solution of the present invention is implemented as follows: A nano-calcium carbonate dispersion stabilizer, wherein the raw materials for preparing the nano-calcium carbonate dispersion stabilizer include the following components by weight: 10-20 parts of triisopropanolamine, 80-90 parts of an acrylic acid-acrylamide copolymer, and 0.1-0.5 parts of thickening resin.

[0009] Furthermore, the raw materials for preparing the nano-calcium carbonate dispersion stabilizer include the following components by weight: 13-17 parts of triisopropanolamine, 83-88 parts of acrylic acid-acrylamide copolymer, and 0.1-0.5 parts of thickening resin.

[0010] Furthermore, the effective component of the triisopropanolamine is ≥85%.

[0011] Furthermore, the acrylic acid-acrylamide copolymer has a weight-average molecular weight of 2000-3000.

[0012] Furthermore, the acrylic acid-acrylamide copolymer has a weight-average molecular weight of 2500-3000.

[0013] Furthermore, the thickening resin has a molecular weight of 6-8 million.

[0014] Furthermore, the thickening resin has a molecular weight of 7 million to 7.5 million.

[0015] This invention also proposes a method for preparing the above-mentioned nano-calcium carbonate dispersion stabilizer, the method comprising the following steps: The nano-calcium carbonate dispersion stabilizer is prepared by mixing triisopropanolamine, acrylic acid-acrylamide copolymer, and thickening resin in a set ratio and stirring until uniformly dissolved.

[0016] The present invention further proposes a nano-calcium carbonate dispersion, wherein the nano-calcium carbonate dispersion contains the above-mentioned nano-calcium carbonate dispersion stabilizer and nano-calcium carbonate.

[0017] The nano-calcium carbonate dispersant and stabilizer of the present invention combines triisopropanolamine, acrylic acid-acrylamide copolymer and thickening resin, and has a high dispersing effect, especially for nano-calcium carbonate, and can effectively prevent nano-calcium carbonate from agglomerating.

[0018] The nano-calcium carbonate dispersion of the present invention, by adding a nano-calcium carbonate dispersion stabilizer, can keep the nano-calcium carbonate in a dispersed state for a long time, and when used to prepare cement concrete, it can improve the early strength of the concrete. Detailed Implementation

[0019] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0020] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods. Unless otherwise specified, the experimental materials used in the following embodiments were purchased from conventional biochemical reagent stores. Furthermore, unless otherwise specified in this embodiment, the terms and processes involved in this embodiment can be understood in accordance with general knowledge and conventional methods in the prior art.

[0021] A nano-calcium carbonate dispersion stabilizer is disclosed. The raw materials for preparing the nano-calcium carbonate dispersion stabilizer include the following components by weight: 10-20 parts triisopropanolamine, 80-90 parts an acrylic acid-acrylamide copolymer, and 0.1-0.5 parts thickening resin. Preferably, the effective component of the triisopropanolamine is ≥85%; the weight-average molecular weight of the acrylic acid-acrylamide copolymer is 2000-3000, preferably 2500-3000; and the molecular weight of the thickening resin is 6-8 million, preferably 7-7.5 million.

[0022] The preferred amounts of raw materials for preparing the above-mentioned nano-calcium carbonate dispersion stabilizer are 13-17 parts of triisopropanolamine, 83-88 parts of acrylic acid-acrylamide copolymer, and 0.1-0.5 parts of thickening resin.

[0023] This invention also proposes a method for preparing the above-mentioned nano-calcium carbonate dispersion stabilizer, the method comprising the following steps: Triisopropanolamine, acrylic acid-acrylamide copolymer, and thickening resin were mixed in a set ratio and stirred until uniformly dissolved to obtain nano-calcium carbonate dispersion stabilizer.

[0024] In this invention, a nano-calcium carbonate dispersion stabilizer is prepared. Triisopropanolamine has a charge-neutralizing effect; its action on the surface of nano-calcium carbonate neutralizes the surface charge, reduces surface energy, and makes the nano-calcium carbonate less prone to aggregation. The acrylic acid-acrylamide copolymer can be adsorbed onto the surface of the nano-calcium carbonate, dispersing it through charge repulsion, steric hindrance, and the water film effect, further reducing aggregation. The thickening resin effectively increases the viscosity of the dispersion stabilizer; the increased viscosity ensures the stability of the dispersed nano-calcium carbonate, preventing it from settling and re-aggregating after a period of time. This nano-calcium carbonate dispersion stabilizer, through the combination of triisopropanolamine, the acrylic acid-acrylamide copolymer, and the thickening resin, exhibits high dispersing power, particularly effective for dispersing nano-calcium carbonate and preventing its aggregation.

[0025] The present invention further proposes a nano-calcium carbonate dispersion containing the above-mentioned nano-calcium carbonate dispersion stabilizer and nano-calcium carbonate.

[0026] The nano-calcium carbonate dispersion of the present invention, by adding a nano-calcium carbonate dispersion stabilizer, can keep the nano-calcium carbonate in a dispersed state for a long time, and when used to prepare cement concrete, it can improve the early strength of the concrete.

[0027] The specific implementation scheme of the present invention will be described in detail below. Example

[0028] By weight, triisopropanolamine, acrylic acid-acrylamide copolymer, and thickening resin are mixed and stirred until uniformly dissolved to prepare nano-calcium carbonate dispersion stabilizer. The amounts of raw materials used in the preparation of the above-mentioned nano-calcium carbonate dispersion stabilizer are 10 parts triisopropanolamine, 90 parts acrylic acid-acrylamide copolymer, and 0.4 parts thickening resin. Preferably, the effective component of the above-mentioned triisopropanolamine is ≥85%; the weight-average molecular weight of the acrylic acid-acrylamide copolymer is 2000, and the molecular weight of the thickening resin is 6 million.

[0029] A nano-calcium carbonate dispersion was prepared by compounding the above-mentioned nano-calcium carbonate dispersion stabilizer, nano-calcium carbonate and water, wherein the mass concentration of nano-calcium carbonate was 2%, and the mixture was mechanically stirred at 5000 rpm for 1 hour. The water in the nano-calcium carbonate solution was deducted during the concrete mixing process.

[0030] The performance of the above-described embodiments was tested through concrete experiments. Cement, sand, gravel, water, and nano-calcium carbonate dispersion were mixed and stirred evenly. The cement was Esheng PO 42.5 cement, the sand was medium sand with a fineness modulus of 2.7, and the gravel was continuously graded crushed stone ranging from 5mm to 25mm. The mix proportion of the single-unit concrete was cement:sand:gravel:water:nano-calcium carbonate = 360:810:1062:166:5. Example

[0031] By weight, triisopropanolamine, acrylic acid-acrylamide copolymer, and thickening resin are mixed and stirred until uniformly dissolved to prepare nano-calcium carbonate dispersion stabilizer. The amounts of raw materials used in the preparation of the above-mentioned nano-calcium carbonate dispersion stabilizer are 15 parts triisopropanolamine, 85 parts acrylic acid-acrylamide copolymer, and 0.3 parts thickening resin. Preferably, the effective component of the above-mentioned triisopropanolamine is ≥85%; the weight-average molecular weight of the acrylic acid-acrylamide copolymer is 2800, and the molecular weight of the thickening resin is 7.5 million.

[0032] A nano-calcium carbonate dispersion was prepared by compounding the above-mentioned nano-calcium carbonate dispersion stabilizer, nano-calcium carbonate and water, wherein the mass concentration of nano-calcium carbonate was 2%, and the mixture was mechanically stirred at 5000 rpm for 1 hour. The water in the nano-calcium carbonate solution was deducted during the concrete mixing process.

[0033] The performance of the above-described embodiments was tested through concrete experiments. Cement, sand, gravel, water, and nano-calcium carbonate dispersion were mixed and stirred evenly. The cement was Esheng PO 42.5 cement, the sand was medium sand with a fineness modulus of 2.7, and the gravel was continuously graded crushed stone ranging from 5mm to 25mm. The mix proportion of the single-unit concrete was cement:sand:gravel:water:nano-calcium carbonate = 360:810:1062:166:5. Example

[0034] By weight, triisopropanolamine, acrylic acid-acrylamide copolymer, and thickening resin are mixed and stirred until uniformly dissolved to prepare nano-calcium carbonate dispersion stabilizer. The amounts of raw materials used in the preparation of the above-mentioned nano-calcium carbonate dispersion stabilizer are 20 parts triisopropanolamine, 80 parts acrylic acid-acrylamide copolymer, and 0.2 parts thickening resin. Preferably, the effective component of the above-mentioned triisopropanolamine is ≥85%; the weight-average molecular weight of the acrylic acid-acrylamide copolymer is 3000; and the molecular weight of the thickening resin is 8 million.

[0035] A nano-calcium carbonate dispersion was prepared by compounding the above-mentioned nano-calcium carbonate dispersion stabilizer, nano-calcium carbonate and water, wherein the mass concentration of nano-calcium carbonate was 2%, and the mixture was mechanically stirred at 5000 rpm for 1 hour. The water in the nano-calcium carbonate solution was deducted during the concrete mixing process.

[0036] The performance of the above-described embodiments was tested through concrete experiments. Cement, sand, gravel, water, and nano-calcium carbonate dispersion were mixed and stirred evenly. The cement was Esheng PO 42.5 cement, the sand was medium sand with a fineness modulus of 2.7, and the gravel was continuously graded crushed stone ranging from 5mm to 25mm. The mix proportion of the single-unit concrete was cement:sand:gravel:water:nano-calcium carbonate = 360:810:1062:166:5.

[0037] Comparative Example 1 This comparative example is basically the same as Example 2, except that nano-calcium carbonate is not added in this comparative example, and the specific process includes the following.

[0038] By weight, triisopropanolamine, acrylic acid-acrylamide copolymer, and thickening resin are mixed and stirred until uniformly dissolved to prepare nano-calcium carbonate dispersion stabilizer. The amounts of raw materials used in the preparation of the above-mentioned nano-calcium carbonate dispersion stabilizer are 15 parts triisopropanolamine, 85 parts acrylic acid-acrylamide copolymer, and 0.3 parts thickening resin. Preferably, the effective component of the above-mentioned triisopropanolamine is ≥85%; the weight-average molecular weight of the acrylic acid-acrylamide copolymer is 2800, and the molecular weight of the thickening resin is 7.5 million.

[0039] The performance of the above-described embodiments was tested through concrete experiments. Cement, sand, gravel, and water were mixed and stirred evenly. The cement was Esheng PO 42.5 cement, the sand was medium sand with a fineness modulus of 2.7, and the gravel was continuously graded crushed stone ranging from 5mm to 25mm. The mix proportion of the concrete per cubic meter was cement:sand:gravel:water = 360:810:1062:166.

[0040] Comparative Example 2 This comparative example is basically the same as Example 2, except that no dispersant stabilizer is added in this comparative example, and the specific process includes the following.

[0041] The performance of the above-described embodiments was tested through concrete experiments. Cement, sand, gravel, water, and nano-calcium carbonate were mixed and stirred evenly. The cement was Esheng PO 42.5 cement, the sand was medium sand with a fineness modulus of 2.7, and the gravel was continuously graded crushed stone ranging from 5mm to 25mm. The mix proportion of the single-unit concrete was cement:sand:gravel:water:nano-calcium carbonate = 360:810:1062:166:5.

[0042] The application results are shown in the table below.

[0043] The experimental results show that without the addition of a dispersant and stabilizer, the nano-calcium carbonate solution exhibits significant particle agglomeration and poor stability, with very limited improvement in concrete strength. However, the addition of a dispersant and stabilizer during the preparation of the nano-calcium carbonate solution effectively alleviates the agglomeration of calcium carbonate particles, resulting in good stability. No precipitation occurs after 1 day of storage, and the solution significantly improves concrete strength, especially early-stage strength, with a more than 30% increase in 3-day compressive strength.

[0044] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

Claims

1. A nano calcium carbonate dispersion stabilizer, characterized by: The raw materials for preparing the nano-calcium carbonate dispersion stabilizer include the following components by weight: 10-20 parts of triisopropanolamine, 80-90 parts of acrylic acid-acrylamide copolymer, and 0.1-0.5 parts of thickening resin.

2. The nano calcium carbonate dispersion stabilizer according to claim 1, characterized in that: The raw materials for preparing the nano-calcium carbonate dispersion stabilizer include the following components by weight: 13-17 parts triisopropanolamine, 83-88 parts acrylic acid-acrylamide copolymer, and 0.1-0.5 parts thickening resin.

3. The nano-calcium carbonate dispersion stabilizer according to claim 1, characterized in that: The effective component of the triisopropanolamine is ≥85%.

4. The nano-calcium carbonate dispersion stabilizer according to claim 1, characterized in that: The acrylic acid-acrylamide copolymer has a weight-average molecular weight of 2000-3000.

5. The nano-calcium carbonate dispersion stabilizer according to claim 1, characterized in that: The acrylic acid-acrylamide copolymer has a weight-average molecular weight of 2500-3000.

6. The nano-calcium carbonate dispersion stabilizer according to claim 1, characterized in that: The thickening resin has a molecular weight of 6-8 million.

7. The nano-calcium carbonate dispersion stabilizer according to claim 6, characterized in that: The thickening resin has a molecular weight of 7 million to 7.5 million.

8. A method for preparing the nano-calcium carbonate dispersion stabilizer according to any one of claims 1-7, characterized in that: The method includes the following steps: The nano-calcium carbonate dispersion stabilizer is prepared by mixing triisopropanolamine, acrylic acid-acrylamide copolymer, and thickening resin in a set ratio and stirring until uniformly dissolved.

9. A nano-calcium carbonate dispersion, characterized in that: The nano-calcium carbonate dispersion contains the nano-calcium carbonate dispersion stabilizer and nano-calcium carbonate as described in any one of claims 1-7.

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