Acid-resistant thickening agent and preparation method thereof

Abstract

The invention discloses an acid-resistant thickening agent and a preparation method thereof, and belongs to the field of polymer science, the thickening agent is a copolymer of oil-soluble methacrylate, aqueous solution methacrylate and 2-acrylamido-2-methylpropanesulfonate, the water-soluble metacrylic acid ester endows the high-molecular polymer with good water solubility, and the oil-soluble metacrylic acid ester endows hydrophobic molecular chain segments of the high-molecular polymer with aggregation in an aqueous solution, so that a local cross-linking effect is achieved, and the thickening performance is improved.

Description

Technical Field: The present invention belongs to the field of polymer science, and particularly relates to a water-soluble polymer suitable for thickening acidic aqueous solutions. Background Art: Acidic aqueous solutions have a wide range of applications in many fields. Thickening acidic aqueous solutions can achieve good effects such as facilitating construction and slow release. Chinese Patent CN118516100A discloses a thickener suitable for oilfield acid fluids, but it requires the use of expensive cage-shaped octakis(3-chloropropyl) silsesquioxane as the main raw material; Chinese Patent CN118703192A discloses an acid fluid for oilfield reservoir stimulation, and the thickeners used, chromium acetate and lactic acid, contain heavy metal ions chromium. Summary of the Invention: The first object of the present invention is to provide a water-soluble polymer suitable for thickening acidic aqueous solutions.

[0004] The second object of the present invention is to provide a preparation method of the water-soluble polymer suitable for thickening acidic aqueous solutions.

[0005] The above objects of the present invention are achieved by the following technical solutions: A water-soluble polymer suitable for thickening acidic aqueous solutions, characterized in that the polymer is a copolymer of an oil-soluble methacrylate, a water-soluble methacrylate, and 2-acrylamido-2-methylpropanesulfonate, wherein the mass fraction of the oil-soluble methacrylate is 0.25 - 91.38%, and the mass fraction of the water-soluble methacrylate is 13.16 - 42.04%. The water-soluble methacrylate endows the polymer with good water solubility, while the oil-soluble methacrylate endows the polymer with hydrophobic molecular segments that aggregate in the aqueous solution, playing a role of local crosslinking and improving the thickening performance. The oil-soluble methacrylate is one of butyl methacrylate and methyl methacrylate or a mixture in any proportion, and the water-soluble methacrylate is one of 2-hydroxyethyl methacrylate and 2-hydroxypropyl methacrylate or a mixture in any proportion. The 2-acrylamido-2-methylpropanesulfonate is an inorganic ammonium salt or an organic amine salt of 2-acrylamido-2-methylpropanesulfonic acid.

[0006] To prepare the polymer suitable for thickening acidic aqueous solutions, first, an oil-soluble methacrylate is dispersed in water using an emulsifier. Examples of suitable emulsifiers include common emulsifiers such as sodium dodecylbenzenesulfonate and sodium dodecyl sulfate. The emulsification method is shear emulsification. Then, 2-acrylamido-2-methylpropanesulfonic acid is dissolved therein, and an inorganic ammonium salt (ammonium bicarbonate or ammonium chloride) or an organic amine (methylamine, triethylamine, ethanolamine, or triethanolamine) in a molar ratio of 28.63 - 100% is added. After thorough stirring and mixing, a water-soluble methacrylate and an initiator are added in proportion to initiate the polymerization reaction. Suitable initiators are redox initiators that can initiate the polymerization reaction at room temperature. Examples of redox initiators include ammonium persulfate - sodium bisulfite and hydrogen peroxide - ascorbic acid. When the reaction solution becomes gelatinous, the reaction ends. The gelatinous polymer solution can be directly cut into strips and minced with a meat grinder for use, or it can be dried in an oven and pulverized with a pulverizer for use.

[0007] Based on the above technical solutions, it is not difficult to find that the core technologies of the present invention include two aspects: First, a water-soluble polymer suitable for thickening acidic aqueous solutions is provided, which is a copolymer containing an oil-soluble methacrylate, a water-soluble methacrylate, and 2-acrylamido-2-methylpropanesulfonate. Among them, the mass fraction of the oil-soluble methacrylate is 0.25 - 91.38%, and the mass fraction of the water-soluble methacrylate is 13.16 - 42.04%. The water-soluble methacrylate endows the polymer with good water solubility, while the oil-soluble methacrylate endows the polymer with hydrophobic molecular segments that aggregate in the aqueous solution, playing a role of local cross-linking and improving the thickening performance. Second, a manufacturing method of the water-soluble polymer suitable for thickening acidic aqueous solutions is provided. This method couples the emulsion polymerization of the oil-soluble methacrylate with the aqueous solution polymerization of the water-soluble monomer, simplifying the manufacturing process. Specific embodiments: Example 1 Dissolve 1.9 g of sodium dodecyl sulfate in 108 g of water, add 13 g of butyl methacrylate, and stir with a shear emulsifier at a speed of 28,000 revolutions per minute for 45 minutes. Add 26 g of 2-acrylamido-2-methylpropanesulfonic acid, stir to dissolve, add 9.3 g of ammonium bicarbonate, stir to dissolve, then add 20 g of 2-hydroxyethyl methacrylate, 1.2 ml of a 10% aqueous solution of ammonium persulfate, and 1.2 ml of a 10% aqueous solution of sodium bisulfite. After slightly stirring, let it stand for reaction. After 6 hours, cut 6.3 g of the obtained gelatinous polymer solution with scissors and dissolve it in 86 g of an 8% hydrochloric acid solution. The measured viscosity of the solution is 283 mPaS.

[0009] Example 2 Dissolve 2.8 g of sodium dodecylbenzenesulfonate in 143 g of water, add 8 g of methyl methacrylate, stir with a shear emulsifier at a speed of 28,000 revolutions per minute for 26 min, add 43 g of 2-acrylamido-2-methylpropanesulfonic acid, stir to dissolve, add 21 g of triethylamine, stir to dissolve, then add 12 g of hydroxypropyl methacrylate, 2 ml of 30% hydrogen peroxide solution by mass fraction and 1.0 ml of 10% ascorbic acid aqueous solution. After slightly stirring, let it stand for reaction. After 40 min, cut 4.7 g of the obtained colloidal polymer solution with scissors and dissolve it in 65 g of 12% acetic acid solution, and measure the solution viscosity to be 91 mPaS.

[0010] Example 3 Dissolve 1.5 g of sodium dodecyl sulfate in 86 g of water, add 3 g of butyl methacrylate and 5 g of methyl methacrylate, stir with a shear emulsifier at a speed of 28,000 revolutions per minute for 30 min, add 31 g of 2-acrylamido-2-methylpropanesulfonic acid, stir to dissolve, add 11 g of ammonium chloride, stir to dissolve, then add 8 g of hydroxyethyl methacrylate and 10 g of hydroxypropyl methacrylate, 1.0 ml of 10% ammonium persulfate aqueous solution by mass fraction and 1.0 ml of 10% sodium bisulfite aqueous solution. After slightly stirring, let it stand for reaction. After 24 hours, cut 3.8 g of the obtained colloidal polymer solution with scissors and dissolve it in 100 g of 10% sulfuric acid solution, and measure the solution viscosity to be 152 mPaS.

[0011] Example 4 Dissolve 2.1 g of sodium dodecyl sulfate in 133 g of water, add 8 g of butyl methacrylate, stir with a shear emulsifier at a speed of 28,000 revolutions per minute for 20 min, add 45 g of 2-acrylamido-2-methylpropanesulfonic acid and stir to dissolve, add 36 g of ethanolamine, stir to dissolve, then add 12 g of hydroxyethyl methacrylate, 1.5 ml of 30% hydrogen peroxide solution by mass fraction and 1.5 ml of 10% ascorbic acid aqueous solution. After slightly stirring, let it stand for reaction. After 2 hours, cut 8.3 g of the obtained colloidal polymer solution with scissors and dissolve it in 94 g of 21% hydrochloric acid solution, and measure the solution viscosity to be 116 mPaS.

[0012] The above embodiments and examples of the present invention are only for helping to understand the present invention and do not constitute a limitation to the present invention. Within the scope expressed by the technical solution and claims of the present invention, the purpose of the present invention can be achieved.

Claims

1. An acid-resistant thickener, characterized in that: The thickener is a copolymer of oil-soluble methacrylate, water-soluble methacrylate and 2-acrylamide-2-methylpropane sulfonate, wherein the mass fraction of the oil-soluble methacrylate is 0.25-91.38%, and the mass fraction of the water-soluble methacrylate is 13.16-42.04%.

2. The acid-resistant thickener according to claim 1, wherein: The oil-soluble methacrylate is one of butyl methacrylate and methyl methacrylate or a mixture thereof in any proportion, and the water-soluble methacrylate is one of hydroxyethyl methacrylate and hydroxypropyl methacrylate or a mixture thereof in any proportion.

3. The acid-resistant thickener according to claim 1, characterized in that: The 2-acrylamide-2-methylpropanesulfonate is an inorganic ammonium salt or an organic amine salt of 2-acrylamide-2-methylpropanesulfonic acid.

4. The preparation method of the acid-resistant thickening agent according to claim 1, characterized in that: The method comprises the following steps: firstly dissolving an emulsifier in water, adding an oil-soluble methacrylate, and stirring at high speed with a shear emulsifier to disperse the oil-soluble methacrylate in water; then dissolving 2-acrylamide-2-methylpropanesulfonic acid in the water, adding an inorganic ammonium salt or an organic amine in a molar ratio of 28.63-100%, stirring and mixing the mixture thoroughly, and then adding a water-soluble methacrylate and an initiator in proportion to initiate a polymerization reaction; When the reaction solution becomes gelatinous, it can be directly cut into strips and minced with a meat grinder, or it can be dried in a drying oven and crushed with a powder grinder before use; the organic amine is methylamine, triethylamine, ethanolamine or triethanolamine, and the inorganic ammonium salt is ammonium bicarbonate or ammonium chloride.