High-stability non-silicon defoaming agent and preparation method thereof

Abstract

The invention discloses a high-stability non-silicon defoaming agent and a preparation method thereof, and relates to the technical field of defoaming agents. The high-stability non-silicon defoaming agent comprises the following raw materials in parts by weight: 15-25 parts of hydrogenated castor oil, 8-15 parts of perfluoropolyether carboxylic acid, 5-10 parts of fatty alcohol, 10-18 parts of fatty acid ester, 3-8 parts of a stabilizer, 4-10 parts of an emulsifier and 60-70 parts of deionized water. The preparation method comprises the following steps: reacting 2-(4-aminophenylazo) benzoic acid with polytetrahydrofuran glycol to obtain an intermediate 1, reacting the intermediate 1 with 3-mercaptopropionic acid to obtain an intermediate 2, and reacting the intermediate 2 with methoxypolyethylene glycol to prepare the stabilizer. The high-stability non-silicon defoaming agent prepared by the invention has good stability and rapid foam breaking and lasting foam inhibition capabilities.

Description

Technical Field

[0001] The present invention relates to the technical field of defoaming agents, and in particular to a high-stability non-silicon defoaming agent and a preparation method thereof. Background Art

[0002] Defoamers, key additives for controlling foam in industrial production, are widely used in fields such as papermaking, printing and dyeing, fermentation, and petrochemicals. Traditional defoamers are primarily categorized into two types: silicone and non-silicone. While silicone defoamers (such as polydimethylsiloxane) offer high defoaming efficiency, they can easily leave residual silicon spots, impacting subsequent processes such as coating and film forming. Non-silicone defoamers (such as fatty acid esters and polyethers) offer excellent compatibility but generally suffer from poor stability (emulsions tend to stratify and break at high temperatures) and insufficient defoaming durability (active ingredients are easily lost), making them difficult to meet the demands of modern industry for long-term, highly stable defoaming.

[0003] Chinese invention patent publication number CN119303348A discloses a non-silicon defoamer, its synthesis method, and its application in scandium extraction. The defoamer is synthesized from three components—components A, B, and C—through a two-step reaction. The specific synthesis steps are: 1) esterification of amino acid A with fatty alcohol B to form amino ester D; and 2) substitution reaction of amino ester D with triazine C to obtain the non-silicon defoamer. This defoamer has a wide range of applications, including front-end scandium extraction from laterite nickel ore hydrometallurgy and open-circuit scandium impurity removal in MHP hydrometallurgy. It is added as an auxiliary agent during the extraction process to reduce liquid surface tension, prevent the formation and accumulation of third phases, reduce emulsification, and improve process stability and output quality. While it has significant industrial application value, its dynamic stability remains limited, making it difficult to achieve stable, long-term defoaming. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the present invention aims to provide a highly stable non-silicon defoaming agent and a preparation method thereof.

[0005] To achieve the above object, the present invention is implemented through the following technical solutions: A highly stable non-silicon defoamer comprises the following raw materials in parts by weight: 15-25 parts of hydrogenated castor oil, 8-15 parts of perfluoropolyether carboxylic acid, 5-10 parts of fatty alcohol, 10-18 parts of fatty acid ester, 3-8 parts of stabilizer, 4-10 parts of emulsifier and 60-70 parts of water.

[0006] The stabilizer is prepared by the following method: S1: Under nitrogen protection, 2-(4-aminophenylazo)benzoic acid, triethylamine, and anhydrous DMF were mixed, and a solution of 9-fluorenylmethyl chloroformate in anhydrous DMF was slowly added with stirring. Then, polytetrahydrofuran diol, (1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride), and 4-dimethylaminopyridine were added to react to obtain intermediate 1; S2: Under nitrogen protection, 3-mercaptopropionic acid was mixed with anhydrous DMF, and 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide were added for activation; then, the intermediate 1 and triethylamine in DMF solution were slowly added to react to obtain intermediate 2; S3: Under nitrogen protection, the intermediate 2, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite and anhydrous DMF were mixed, and polyethylene glycol monomethyl ether and p-toluenesulfonic acid were added to react to obtain a stabilizer.

[0007] In step S1, the feeding mass ratio of described polytetrahydrofuran diol and 2-(4-aminophenylazo) benzoic acid is 1:(0.5-0.55).

[0008] In step S2, the mass ratio of the intermediate 1 and 3-mercaptopropionic acid is 1:(0.15-0.16).

[0009] In step S3, the mass ratio of the intermediate 2 to polyethylene glycol monomethyl ether is 1:(2.5-2.7).

[0010] The reaction temperature of step S1 is 25-30° C., and the reaction time is 14-16 h.

[0011] The reaction temperature of step S2 is 25-35° C., and the reaction time is 10-12 h.

[0012] The reaction temperature of step S3 is 120-140° C., and the reaction time is 11-13 h.

[0013] The hydrogenated castor oil is one of PEG-40 hydrogenated castor oil and PEG-60 hydrogenated castor oil.

[0014] The fatty alcohol is one of lauryl alcohol, cetyl alcohol and stearyl alcohol; the fatty acid ester is one of glyceryl monooleate and sorbitan monostearate.

[0015] The emulsifier is epoxy triacetate.

[0016] A method for preparing a highly stable non-silicon defoamer comprises the following steps: (1) Weigh by weight: 15-25 parts of hydrogenated castor oil, 8-15 parts of perfluoropolyether carboxylic acid, 5-10 parts of fatty alcohol, 10-18 parts of fatty acid ester, 3-8 parts of stabilizer, 4-10 parts of emulsifier, and 60-70 parts of deionized water; (2) Melt hydrogenated castor oil, add fatty alcohol and fatty acid ester, stir and mix, add perfluoropolyether carboxylic acid, and shear at high speed to obtain oil phase; add emulsifier into water, and ultrasonicate to obtain water phase; preheat the water phase, slowly drop the oil phase into the water phase under high-speed stirring, continue stirring after dropping, high-pressure homogenize 3 times, cool the homogenized emulsion, add stabilizer, stir and mix, and vacuum defoam to obtain a highly stable non-silicone defoaming agent.

[0017] Due to the adoption of the above technical solution, the beneficial effects of the present invention include: The stabilizer prepared by the present invention comprises a hydrophobic polytetrahydrofuran diol segment, an azobenzene dynamic structure, and a hydrophilic polyethylene glycol monomethyl ether segment. This is an amphiphilic block stabilizer containing a dynamic structure, breaking the limitations of static protection, achieving stable long-term bubble breaking, and improving bubble breaking speed and foam suppression capabilities. The interfacial anchoring effect between the azobenzene dynamic bond in its molecular structure and the block segment significantly enhances the stability, environmental tolerance, and defoaming and foam suppression capabilities of the defoamer. DETAILED DESCRIPTION

[0018] The present invention will be further described below with reference to the embodiments, but the present invention is not limited to these embodiments.

[0019] Example 1 Preparation of stabilizer: S1: 5 g of 2-(4-aminophenylazo)benzoic acid and 3.4 g of triethylamine were added to 100 ml of anhydrous DMF, stirred and mixed, 30 ml of an anhydrous DMF solution containing 6.2 g of chloroformic acid-9-fluorenylmethyl ester was slowly added dropwise at 0°C (dropwise addition for 20 min), stirred at 25°C for 12 h, then 10 g of polytetrahydrofuran diol (number average molecular weight 1000), 2.6 g of (1-ethyl-(3-dimethylaminopropyl) carbodiimide hydrochloride) and 0.02 g of 4-dimethylaminopyridine were added, stirred for 15 min, reacted at 25°C for 16 h, the reaction liquid was poured into 300 ml of an ice water mixture (containing 15 ml of 1M HCl), stirred for 30 min, neutralized the triethylamine; extracted with ethyl acetate for 3 times (150 ml each time), washed with 150 ml of saturated brine after the organic phase was combined, added with 10 g of anhydrous sodium sulfate and dried for 2 h, filtered, concentrated at 50°C under reduced pressure for 1 h to obtain a concentrated liquid, the concentrated liquid was added into a mixed solution of 50 ml of DMF and piperidine (the mixed volume ratio of DMF and piperidine was 4:1), deprotected by stirring at 25°C for 35 min, then added into 400 ml of a 0.5M HCl solution at 0°C, stirred to precipitate, filtered, washed with 100 ml of cold water, 75 ml of a 5 wt% sodium bicarbonate solution and 100 ml of cold water in sequence, and dried at 40°C under vacuum for 12 h to obtain intermediate 1.

[0020]

[0021] S2: 1.5 g of 3-mercaptopropionic acid was mixed with 50 ml of anhydrous DMF under nitrogen protection; 3.8 g of 1-ethyl-(3-dimethylaminopropyl) carbodiimide hydrochloride and 2.3 g of N-hydroxysuccinimide were weighed, mixed and added into the 3-mercaptopropionic acid solution in two batches (5 min interval between each batch), stirred and activated in an ice bath for 45 min; 10 g of intermediate 1 and 2 g of triethylamine were added into 50 ml of anhydrous DMF, stirred and mixed, the activated 3-mercaptopropionic acid solution was slowly added dropwise (dropwise addition for 20 min), reacted at 25°C for 12 h, the mixture was poured into 200 ml of ice water, filtered, the filter cake was washed with deionized water (3×100 ml), purified by silica gel column chromatography (eluent: dichloromethane / methanol = 10:1), rotary evaporation at 65°C for 2 h to obtain intermediate 2; the reaction equation is as follows: V / V

[0022] ​S3: Under nitrogen protection, 10g of intermediate 2 and 0.2g of bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite were added to 150ml of anhydrous DMF, stirred and mixed, 25g of polyethylene glycol monomethyl ether (number average molecular weight 2000) and 0.5g of p-toluenesulfonic acid were added, and the mixture was reacted at 120°C for 13h, cooled to room temperature, and 50ml of saturated sodium bicarbonate solution was added and stirred for 30min. After separation, the organic phase was retained and washed with 100ml of deionized water and 100ml of saturated brine in sequence, dried with 10g of anhydrous sodium sulfate for 2h, filtered, and rotary evaporated at 60°C for 3h. 100ml of dichloromethane was added to dissolve the mixture and purified by silica gel column chromatography (eluent: petroleum ether / ethyl acetate). V / V =5:1) and then rotary evaporated at 50°C for 3 h to obtain a stabilizer. The reaction equation is as follows:

[0023] Example 2 Preparation of stabilizer: S1: Under nitrogen protection, 5.3 g of 2-(4-aminophenylazo)benzoic acid and 3.4 g of triethylamine were added to 100 ml of anhydrous DMF and stirred to mix. At 0°C, 30 ml of anhydrous DMF solution containing 6.2 g of 9-fluorenylmethyl chloroformate was slowly added dropwise (dropwise addition for 20 min), and stirred at 25°C for 12 h. Then, 10 g of polytetrahydrofuran diol (number average molecular weight 1000), 2.6 g of (1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride) and 0.02 g of 4-dimethylaminopyridine were added, stirred for 15 min, and reacted at 25°C for 15 h. The reaction solution was poured into 300 ml of ice-water mixture (containing 15 ml of 1M The mixture was added to a 50 mL mixture of DMF and piperidine (the volume ratio of DMF to piperidine was 4:1) and stirred at 25°C for 35 min for deprotection. The mixture was then added to 400 mL of 0.5 M HCl solution at 0°C and stirred to separate the precipitate. The precipitate was filtered and washed with 100 mL of cold water, 75 mL of a 5 wt% sodium bicarbonate solution, and 100 mL of cold water, followed by drying at 40°C for 12 h to obtain intermediate 1.

[0024] S2: Under nitrogen protection, 1.55 g of 3-mercaptopropionic acid was mixed with 50 ml of anhydrous DMF; 3.8 g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and 2.3 g of N-hydroxysuccinimide were weighed, mixed, and added to the 3-mercaptopropionic acid solution in two equal batches (5 min interval between each batch), and stirred for activation in an ice bath for 45 min; 10 g of intermediate 1 and 2 g of triethylamine were added to 50 ml of anhydrous DMF at room temperature, stirred and mixed, and the activated 3-mercaptopropionic acid solution was slowly added (dropwise addition for 20 min), and reacted at 30°C for 11 h. The mixture was poured into 200 ml of ice water, filtered, and the filter cake was washed with deionized water (3×100 ml). The product was purified by silica gel column chromatography (eluent: dichloromethane / methanol) V / V =10:1) and purified by rotary evaporation at 65 °C for 2 h to obtain intermediate 2.

[0025] S3: Under nitrogen protection, 10g of intermediate 2 and 0.2g of bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite were added to 150ml of anhydrous DMF, stirred and mixed, 26g of polyethylene glycol monomethyl ether (number average molecular weight 2000) and 0.5g of p-toluenesulfonic acid were added, and the mixture was reacted at 130°C for 12h, cooled to room temperature, 50ml of saturated sodium bicarbonate solution was added and stirred for 30min. After separation, the organic phase was retained and washed with 100ml of deionized water and 100ml of saturated brine in sequence, dried with 10g of anhydrous sodium sulfate for 2h, filtered, and rotary evaporated at 60°C for 3h. 100ml of dichloromethane was added to dissolve the mixture and purified by silica gel column chromatography (eluent: petroleum ether / ethyl acetate). V / V =5:1) and rotary evaporation at 50°C for 3 h to obtain the stabilizer.

[0026] Example 3 Preparation of stabilizer: S1: Under nitrogen protection, 5.5 g of 2-(4-aminophenylazo)benzoic acid and 3.4 g of triethylamine were added to 100 ml of anhydrous DMF and stirred to mix. At 0°C, 30 ml of anhydrous DMF solution containing 6.2 g of 9-fluorenylmethyl chloroformate was slowly added dropwise (dropwise addition for 20 min), and stirred at 25°C for 12 h. Then, 10 g of polytetrahydrofuran diol (number average molecular weight 1000), 2.6 g of (1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride) and 0.02 g of 4-dimethylaminopyridine were added, stirred for 15 min, and reacted at 30°C for 14 h. The reaction solution was poured into 300 ml of ice-water mixture (containing 15 ml of 1M The mixture was added to a 50 mL mixture of DMF and piperidine (the volume ratio of DMF to piperidine was 4:1) and stirred at 25°C for 35 min for deprotection. The mixture was then added to 400 mL of 0.5 M HCl solution at 0°C and stirred to separate the precipitate. The precipitate was filtered and washed with 100 mL of cold water, 75 mL of a 5 wt% sodium bicarbonate solution, and 100 mL of cold water, followed by drying at 40°C for 12 h to obtain intermediate 1.

[0027] S2: Under nitrogen protection, 1.6 g of 3-mercaptopropionic acid was mixed with 50 ml of anhydrous DMF; 3.8 g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and 2.3 g of N-hydroxysuccinimide were weighed, mixed, and added to the 3-mercaptopropionic acid solution in two equal batches (5 min interval between each batch), and stirred for activation in an ice bath for 45 min; 10 g of intermediate 1 and 2 g of triethylamine were added to 50 ml of anhydrous DMF at room temperature, stirred and mixed, and the activated 3-mercaptopropionic acid solution was slowly added (dropwise addition for 20 min), and reacted at 35°C for 10 h. The mixture was poured into 200 ml of ice water, filtered, and the filter cake was washed with deionized water (3×100 ml). Silica gel column chromatography (eluent: dichloromethane / methanol) was performed. V / V =10:1) and purified by rotary evaporation at 65 °C for 5 h to obtain intermediate 2.

[0028] S3: Under nitrogen protection, 10g of intermediate 2 and 0.2g of bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite were added to 150ml of anhydrous DMF, stirred and mixed, 27g of polyethylene glycol monomethyl ether (number average molecular weight 2000) and 0.5g of p-toluenesulfonic acid were added, and the mixture was reacted at 140°C for 11h, cooled to room temperature, and 50ml of saturated sodium bicarbonate solution was added and stirred for 30min. After separation, the organic phase was retained and washed with 100ml of deionized water and 100ml of saturated brine in sequence, dried with 10g of anhydrous sodium sulfate for 2h, filtered, and rotary evaporated at 60°C for 3h. 100ml of dichloromethane was added to dissolve the mixture and purified by silica gel column chromatography (eluent: petroleum ether / ethyl acetate). V / V =5:1) and rotary evaporation at 50°C for 3 h to obtain the stabilizer.

[0029] Example 4 Preparation of a highly stable non-silicon defoamer: (1) Weigh by weight: 15 g hydrogenated castor oil (PEG-40 hydrogenated castor oil), 8 g perfluoropolyether carboxylic acid, 5 g fatty alcohol (lauryl alcohol), 10 g fatty acid ester (glyceryl monooleate), 3 g stabilizer (prepared in Example 1), 4 g emulsifier (epoxy triacetate), and 60 g water; (2) Stir hydrogenated castor oil in an oil bath at 85°C until it melts, add fatty alcohol and fatty acid ester, stir at 300 rpm for 30 min, add perfluoropolyether carboxylic acid, heat to 90°C, and high-speed shear at 2000 rpm for 1 h to obtain the oil phase; add emulsifier into water, ultrasonicate at 50 kHz for 20 min to obtain the water phase; preheat the water phase to 85°C, slowly drop the oil phase into the water phase under high-speed stirring at 1500 rpm for 1 h, continue stirring for 30 min after the addition, homogenize 3 times using AH-BASIC 30 high-pressure homogenizer (pressure 25 MPa), cool the homogenized emulsion to 45°C, add stabilizer, stir at 500 rpm for 1 h, vacuum defoam (-0.09 MPa, 45°C) for 30 min, and cool to obtain a highly stable non-silicone defoaming agent.

[0030] Example 5 Preparation of a highly stable non-silicon defoamer: (1) Weigh by weight: 20 g hydrogenated castor oil (PEG-60 hydrogenated castor oil), 12 g perfluoropolyether carboxylic acid, 8 g fatty alcohol (cetyl alcohol), 14 g fatty acid ester (sorbitan monostearate), 5 g stabilizer (prepared in Example 2), 7 g emulsifier (epoxy triacetate), and 65 g water; (2) Stir hydrogenated castor oil in an oil bath at 85°C until it is melted, add fatty alcohol and fatty acid ester, stir at 300 rpm for 30 min, add perfluoropolyether carboxylic acid, heat to 90°C, and high-speed shear at 2000 rpm for 1 h to obtain the oil phase; add emulsifier into water, ultrasonicate at 50 kHz for 20 min to obtain the water phase; preheat the water phase to 85°C, slowly drop the oil phase into the water phase under high-speed stirring at 1500 rpm for 1 h, continue stirring for 30 min after the addition, homogenize 3 times using AH-BASIC 30 high-pressure homogenizer (pressure 25 MPa), cool the homogenized emulsion to 45°C, add stabilizer, stir at 500 rpm for 1 h, vacuum defoam (-0.09 MPa, 45°C) for 30 min, and cool to obtain a highly stable non-silicone defoaming agent.

[0031] Example 6 Preparation of a highly stable non-silicon defoamer: (1) Weigh by weight: 25 g hydrogenated castor oil (PEG-40 hydrogenated castor oil), 15 g perfluoropolyether carboxylic acid, 10 g fatty alcohol (stearyl alcohol), 18 g fatty acid ester (glyceryl monooleate), 8 g stabilizer (prepared in Example 3), 10 g emulsifier (epoxy triacetate), and 70 g water; (2) Stir hydrogenated castor oil in an oil bath at 85°C until it is melted, add fatty alcohol and fatty acid ester, stir at 300 rpm for 30 min, add perfluoropolyether carboxylic acid, heat to 90°C, and high-speed shear at 2000 rpm for 1 h to obtain the oil phase; add emulsifier into water, ultrasonicate at 50 kHz for 20 min to obtain the water phase; preheat the water phase to 85°C, slowly drop the oil phase into the water phase under high-speed stirring at 1500 rpm for 1 h, continue stirring for 30 min after the addition, homogenize 3 times using AH-BASIC 30 high-pressure homogenizer (pressure 25 MPa), cool the homogenized emulsion to 45°C, add stabilizer, stir at 500 rpm for 1 h, vacuum defoam (-0.09 MPa, 45°C) for 30 min, and cool to obtain a highly stable non-silicone defoaming agent.

[0032] Comparative Example 1 The raw material composition and preparation method of the highly stable non-silicon defoamer are substantially the same as those of Example 5, except that no stabilizer is added to the composition.

[0033] Comparative Example 2 The raw material composition and preparation method of the highly stable non-silicon defoamer are substantially the same as those of Example 5, except that the stabilizer is replaced by an equal weight of a stabilizer prepared by the following method: The preparation method of the stabilizer is basically the same as that of Example 2, except that the 2-(4-aminophenylazo)benzoic acid in step S1 is replaced by an equal weight of 4'-amino-2-biphenylcarboxylic acid.

[0034] Comparative Example 3 The raw material composition and preparation method of the highly stable non-silicon defoamer are substantially the same as those of Example 5, except that the stabilizer is replaced by an equal weight of a stabilizer prepared by the following method: The preparation method of the stabilizer is substantially the same as that of Example 2, except that the polytetrahydrofuran diol (number average molecular weight of 1000 Da) in step S1 is replaced with 2.5 g of polytetrahydrofuran diol having a number average molecular weight of 250 Da.

[0035] Comparative Example 4 The raw material composition and preparation method of the highly stable non-silicon defoamer are substantially the same as those of Example 5, except that the stabilizer is replaced by an equal weight of a stabilizer prepared by the following method: The preparation method of the stabilizer is basically the same as that of Example 2, except that the polytetrahydrofuran diol (number average molecular weight of 1000 Da) in step S1 is replaced by polyethylene glycol (PEG1000) of the same weight.

[0036] Comparative Example 5 The raw material composition and preparation method of the highly stable non-silicon defoamer are substantially the same as those of Example 5, except that the stabilizer is replaced by an equal weight of a stabilizer prepared by the following method: The preparation method of the stabilizer is basically the same as that of Example 2, except that the polyethylene glycol monomethyl ether (number average molecular weight of 2000 Da) in step S3 is replaced by 9.8 g of polyethylene glycol monomethyl ether with a number average molecular weight of 750 Da.

[0037] The PEG-40 hydrogenated castor oil used in the Examples and Comparative Examples of this application is RH-40, produced by BASF GmbH, Germany; the PEG-60 hydrogenated castor oil is RH-60, produced by BASF GmbH, Germany; and the perfluoropolyether carboxylic acid is PFPE-CA-1000, produced by Suzhou Cangmu New Materials Co., Ltd. The CAS number of 2-(4-aminophenylazo)benzoic acid is 85328-89-8.

[0038] The high-stability non-silicon defoamers prepared in Examples 4-6 and Comparative Examples 1-5 were tested for storage stability, high-temperature aging stability, defoaming time, and foam suppression time. The test results are shown in Table 1.

[0039] Storage stability test: The defoamers prepared in Examples 4-6 and Comparative Examples 1-5 were stored at room temperature for 1 month to observe whether stratification occurred.

[0040] High temperature aging stability test: The defoamers prepared in Examples 4-6 and Comparative Examples 1-5 were placed in an electric blast drying oven at 80° C. and aged for 120 h to observe whether delamination occurred.

[0041] Defoaming time test: Prepare 100ml of a 1% sodium dodecylbenzenesulfonate aqueous solution and pour it into a 500ml graduated cylinder. Blow nitrogen gas to the 500 mark. Add 1ml of defoamer and record the time it takes for all bubbles to disappear. Repeat the test three times for each sample, and take the average value as the final defoaming time.

[0042] Foam suppression time test: Prepare 100ml of a 1% sodium dodecylbenzenesulfonate aqueous solution and pour it into a 500ml graduated cylinder. Add 1ml of defoamer. Then, introduce nitrogen gas at a flow rate of 2 L / min and record the time it takes for bubbles to reach the 500 mark. Repeat the test three times for each sample, and take the average value as the final foam suppression time.

[0043] Table 1

[0044] It can be seen from Table 1 that the high-stability non-silicon defoaming agents prepared in Examples 4-6 of the present application have excellent storage stability, high-temperature stability, rapid foam breaking ability and foam suppression ability.

[0045] The non-silicone defoamers prepared in Examples 4-6 exhibit excellent stability, rapid foam breaking, and foam suppression capabilities. This is because the stabilizers prepared in Examples 4-6 have a hydrophilic and hydrophobic long-chain structure. The hydrophilic segments of polyethylene glycol monomethyl ether extend in the aqueous phase to form a hydration layer, which inhibits Brownian motion and collision of defoamer molecules through volume exclusion. The hydrophobic segments of polytetrahydrofuran diol form molecular anchors through van der Waals forces, preventing the stabilizer from falling off the interface, thereby significantly improving the storage stability of the non-silicone defoamer. The stabilizers prepared in Examples have a dynamic azobenzene structure, and the cis-trans isomer equilibrium of azobenzene can dynamically adjust interfacial tension and inhibit Ostwald ripening of the defoamer. Furthermore, the hydrophobic long-chain segments of polytetrahydrofuran diol and the hydrophilic long-chain segments of polyethylene glycol monomethyl ether also have high thermal stability, synergistically improving the high-temperature stability of the non-silicone defoamer. When the defoamer contacts the foam system, environmental stimuli trigger the reversible bond breakage of the stabilizer, rapidly releasing the active defoaming components. After the foam breaks, the remaining unhydrolyzed stabilizer chains form a dynamic protective film on the surface of the foam film, reducing its surface elasticity and preventing new foam formation. Furthermore, the high water solubility of the hydrophilic segments of polyethylene glycol monomethyl ether enables rapid diffusion of the defoamer in the aqueous phase, shortening the time it takes to reach the foam interface. Simultaneously, its steric hindrance prevents the active components from agglomerating, thereby accelerating the rate of foam breaking. The hydrophobic effect of polytetrahydrofuran diol increases the adsorption energy of the active components at the foam interface, inhibiting their loss with the foam film, thereby enhancing the durability of the anti-foaming effect. Therefore, the synergistic effect of the hydrophobic segments of polytetrahydrofuran diol, the dynamic structure of azobenzene, and the hydrophilic segments of polyethylene glycol monomethyl ether enhances both foam breaking and anti-foaming capabilities. By contrast, Comparative Example 1 does not add stabilizing agent, the stabilizing agent prepared by Comparative Example 2 lacks azobenzene dynamic structure, the polytetrahydrofuran diol hydrophobic segment is shorter in the stabilizing agent prepared by Comparative Example 3, the stabilizing agent prepared in Comparative Example 4 lacks the polytetrahydrofuran diol hydrophobic segment, the polyethylene glycol monomethyl ether hydrophilic segment is shorter in the stabilizing agent prepared by Comparative Example 5, so the effect of the stabilizing agent prepared by Comparative Example is poor than embodiment, thereby causing the performance of the non-silicon type defoamer of preparation to be relatively poor.

[0046] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. However, any equivalent changes, modifications and evolutions made by ordinary technicians in this field without departing from the scope of the technical solution of the present invention by using the technical content disclosed above are all equivalent embodiments of the present invention. At the same time, any equivalent changes, modifications and evolutions made to the above embodiments based on the essential technology of the present invention are still within the scope of protection of the technical solution of the present invention.

Claims

1. A highly stable non-silicon defoamer, characterized in that: The invention comprises the following raw materials in parts by weight: 15-25 parts of hydrogenated castor oil, 8-15 parts of perfluoropolyether carboxylic acid, 5-10 parts of fatty alcohol, 10-18 parts of fatty acid ester, 3-8 parts of stabilizer, 4-10 parts of emulsifier, and 60-70 parts of deionized water; The stabilizer is prepared by the following method: S1: Under nitrogen protection, 2-(4-aminophenylazo)benzoic acid, triethylamine, and anhydrous DMF were mixed, and a solution of 9-fluorenylmethyl chloroformate in anhydrous DMF was slowly added with stirring. Then, polytetrahydrofuran diol, (1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride), and 4-dimethylaminopyridine were added to react to obtain intermediate 1; S2: Under nitrogen protection, 3-mercaptopropionic acid was mixed with anhydrous DMF, and 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide were added for activation; then, the intermediate 1 and triethylamine in DMF solution were slowly added to react to obtain intermediate 2; S3: Under nitrogen protection, the intermediate 2, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite and anhydrous DMF were mixed, and polyethylene glycol monomethyl ether and p-toluenesulfonic acid were added to react to obtain a stabilizer.

2. A highly stable non-silicon defoamer according to claim 1, characterized in that: In step S1, the feeding mass ratio of described polytetrahydrofuran diol and 2-(4-aminophenylazo) benzoic acid is 1:(0.5-0.55).

3. A highly stable non-silicon defoamer according to claim 1, characterized in that: In step S2, the mass ratio of the intermediate 1 to 3-mercaptopropionic acid is 1:(0.15-0.16).

4. A highly stable non-silicon defoamer according to claim 1, characterized in that: In step S3, the mass ratio of the intermediate 2 to polyethylene glycol monomethyl ether is 1:(2.5-2.7).

5. A highly stable non-silicon defoamer according to claim 1, characterized in that: The reaction temperature of step S1 is 25-30° C., and the reaction time is 14-16 h.

6. A highly stable non-silicon defoamer according to claim 1, characterized in that: The reaction temperature of step S2 is 25-35° C., and the reaction time is 10-12 h.

7. A highly stable non-silicon defoamer according to claim 1, characterized in that: The reaction temperature of step S3 is 120-140° C., and the reaction time is 11-13 h.

8. A highly stable non-silicon defoamer according to claim 1, characterized in that: The hydrogenated castor oil is one of PEG-40 hydrogenated castor oil and PEG-60 hydrogenated castor oil.

9. A highly stable non-silicon defoamer according to claim 1, characterized in that: The fatty alcohol is one of lauryl alcohol, cetyl alcohol and stearyl alcohol.

10. The highly stable non-silicon defoamer according to claim 1, characterized in that: The fatty acid ester is one of glyceryl monooleate and sorbitan monostearate.

11. A highly stable non-silicon defoamer according to claim 1, characterized in that: The emulsifier is epoxy triacetate.

12. A method for preparing the highly stable non-silicon defoaming agent according to any one of claims 1 to 11, characterized in that: The following steps are involved: (1) Weigh by weight; 15-25 parts of hydrogenated castor oil, 8-15 parts of perfluoropolyether carboxylic acid, 5-10 parts of fatty alcohol, 10-18 parts of fatty acid ester, 3-8 parts of stabilizer, 4-10 parts of emulsifier, 60-70 parts of deionized water; (2) Heat hydrogenated castor oil, add fatty alcohol and fatty acid ester, stir and mix, add perfluoropolyether carboxylic acid, and shear at high speed to obtain oil phase; add emulsifier into water, and ultrasonicate to obtain water phase; preheat the water phase, slowly drop the oil phase into the water phase under high-speed stirring, continue stirring after dropping, high-pressure homogenize 3 times, cool the homogenized emulsion, add stabilizer, stir and mix, and vacuum defoam to obtain a highly stable non-silicone defoaming agent.

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