A degradable defoaming agent and its preparation method and application

Abstract

The present invention belongs to the technical field of defoaming agents, and specifically relates to a degradable defoaming agent, a preparation method thereof, and an application thereof. The degradable vegetable oleic acid amide in the defoaming agent of the present invention is easily dispersed in a liquid, reducing the surface tension of the liquid; the polyol fatty acid ester can form insoluble particles for defoaming; the nanoemulsion stabilizing agent physically and efficiently defoams by adsorbing gas, and has a thickening effect; the fatty alcohol can quickly diffuse to the foam interface, reducing the surface tension to achieve a rapid defoaming effect. The degradable defoaming agent prepared by the present invention has no silicone oil residue, the bio-based components are degradable, and are environmentally friendly. The fatty alcohol and the degradable vegetable oleic acid amide can instantly defoam, the nanoemulsion stabilizing agent and the fatty acid ester can inhibit the foam regeneration effect, and the diethanolamine laurate and Tween 80 can improve the compatibility and dispersibility of the various components of the defoaming agent. Through the synergistic effect of the various components, the defoaming agent has excellent degradability, dispersibility, and anti-foaming properties when applied to coating inks.

Description

Technical Field

[0001] The invention belongs to the technical field of defoaming agents, and particularly relates to a degradable defoaming agent and a preparation method and application thereof. Background Art

[0002] Defoamers are a type of additive that eliminates foam and inhibits foam formation by reducing the surface tension of the system. Their fundamental properties are low surface tension, excellent defoaming performance, stable chemical properties, non-reaction with the defoaming system, good storage stability, and being green, non-toxic, and pollution-free. The commonly used defoamer types are fatty acid esters, polyethers, silicones, and mineral oils. Silicone defoamers are generally more expensive, and their high chemical stability makes them non-degradable. Mineral oil defoamers take months to years to degrade and are prone to oil film contamination. Polyether defoamers can be degraded by microorganisms, but their biodegradability decreases with increasing degree of polymerization. Due to increasing national environmental protection requirements, green, efficient, and biodegradable defoamers have become a future trend.

[0003] The Chinese invention patent with publication number CN113577833B provides a green solid defoamer and its preparation method. It is characterized in that the defoamer uses natural oils as defoaming active ingredients, mineral compounds and biological compounds as carriers, and polyglycerol as a structuring agent, and prepares a green solid defoamer product through atom-economic process means. The preparation steps of the green solid defoamer are as follows: (1) adding the carrier to the mixer M1 and stirring evenly; (2) adding the defoaming active ingredient and the structuring agent to M2 at the same time and stirring evenly; (3) adding the mixture in (2) to the mixer M1 and stirring evenly; (4) crushing or granulating the mixture obtained in (3), and the obtained mixture is the prepared green solid defoamer. The green solid defoamer described in this invention is not only green and environmentally friendly, but also biodegradable and has strong defoaming and anti-attenuation properties. Chinese invention patent publication number CN111790182B discloses a polyol fatty acid ester of behenic acid, stearic acid, and oleic acid, as well as its preparation method and defoamer formulation. The method comprises sequentially esterifying behenic acid, stearic acid, and oleic acid with a polyol in stages to obtain a behenic acid, stearic acid, and oleic acid fatty acid ester. This polyol fatty acid ester is then compounded to produce a defoamer formulation exhibiting excellent defoaming stability over a wide temperature range of 30 to 55°C. However, the prior art lacks further improvements to the components of the fatty acid ester defoamer to improve the degradability, dispersibility, and anti-foaming properties of the defoamer. Summary of the Invention

[0004] The object of the present invention is to provide a degradable defoaming agent and a preparation method and application thereof, so as to solve the technical problem that the prior art has not further improved the structure and components of fatty acid ester defoaming agents to achieve the improvement of the degradability, dispersibility and anti-foaming properties of the defoaming agent.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A degradable defoaming agent is prepared from the following components in parts by weight:

[0007] 10-12 parts of degradable vegetable oleic acid amide, 1-3 parts of diethanolamine laurate, 13-15 parts of polyol fatty acid ester, 1-3 parts of nanoemulsion stabilizing agent, 2-5 parts of Tween 80, 20-30 parts of fatty alcohol and 20-50 parts of deionized water.

[0008] The fatty alcohol is any one of lauryl alcohol, n-octanol and n-decanol.

[0009] Preferably, the preparation method of the degradable plant oleic acid amide comprises the following steps:

[0010] S11. Add 80-120 parts by mass of vegetable oil and 45-65 parts of anhydrous methanol to a reactor, add 98 wt% concentrated sulfuric acid, heat to 80-90° C. and reflux for 5-6 hours, wash with deionized water, let stand and separate, collect the organic phase, add 5-10 parts of anhydrous sodium sulfate to remove water, and distill under low pressure to obtain vegetable oleic acid methyl ester;

[0011] S12. Add 80-100 parts of vegetable oleic acid methyl ester and 15-30 parts of 1,4-diamine to a reactor by mass, add 0.5-1 part of an alkali catalyst, raise the temperature to 70-80° C. and keep the reaction for 3-4 hours, and evaporate under reduced pressure to obtain a crude product of N-(4-aminobutyl) vegetable oleic acid amide. Add the crude product of N-(4-aminobutyl) vegetable oleic acid amide to anhydrous ethanol, heat at 40-50° C. for recrystallization, filter, and evaporate the filtrate under reduced pressure to obtain N-(4-aminobutyl) vegetable oleic acid amide;

[0012] S13. Add 50-80 parts of N-(4-aminobutyl) vegetable oleic acid amide and 30-40 parts of aldose compound into a reactor, add 200-300 parts of methanol, stir until the solid is completely dissolved, heat to 60-70°C and react for 2-3 hours, cool to room temperature, remove methanol by rotary evaporation, wash with methanol and 75-90wt% ethanol solution, and dry at 60-70°C to obtain degradable vegetable oleic acid amide.

[0013] Preferably, the synthesis principle of the degradable plant oleic acid amide is as follows:

[0014]

[0015] For vegetable oil, It is an aldose compound.

[0016] Preferably, the vegetable oil in S11 is any one of castor oil, soybean oil and palm oil.

[0017] Preferably, the amount of 98 wt% concentrated sulfuric acid added in S11 is 1-2% of the mass of the vegetable oil.

[0018] Preferably, the alkaline catalyst in S12 is any one of sodium hydroxide and potassium hydroxide.

[0019] Preferably, the aldose compound in S13 is any one of D-glucose, D-mannose and D-galactose.

[0020] Preferably, the method for preparing the polyol fatty acid ester comprises the following steps:

[0021] S21. Add 80-100 parts by mass of polyol to a reactor, add 0.5-0.8 parts of aluminum trifluoride, stir at a speed of 300-500 r / min for 0.5-1 h, evacuate the reactor to a vacuum with a vacuum pump, heat to 150-170° C., react for 3-4 h, test the hydroxyl value to ensure it is qualified, cool to room temperature, collect the supernatant, and obtain an etherified polyol;

[0022] S22. Add fatty acid and acid catalyst to 80-100 parts of etherified polyol by mass, raise the temperature to 50-60°C and stir at a speed of 300-500 r / min for 0.5-1h, evacuate the reactor to vacuum with a vacuum pump, raise the temperature to 190-230°C and react until the acid value in the system decreases to 7-10KOH / g, cool to room temperature, collect the supernatant, and prepare polyol fatty acid ester.

[0023] Preferably, the polyol in S21 is any one of sorbitol, mannitol and xylitol.

[0024] Preferably, the fatty acid in S22 is any one of lauric acid, myristic acid, and oleic acid.

[0025] Preferably, the molar ratio of fatty acid to polyol in S22 is 1.4-1.6:0.9-1.1, and the amount of acid catalyst added is 0.5-0.8% of the total weight of oleic acid and etherified polyol.

[0026] Preferably, the acid catalyst in S22 is any one of 98 wt % concentrated sulfuric acid, p-toluenesulfonic acid, and phosphoric acid.

[0027] Preferably, the preparation method of the nanoemulsion stabilizing agent comprises the following steps:

[0028] S31. Add 7 to 10 parts of ethyl orthosilicate to 50 to 100 parts of anhydrous ethanol, add 1 to 2 parts of octadecyltrimethoxysilane and 0.5 to 1 part of methyltriethoxysilane, add 5 to 10 wt % of dilute hydrochloric acid dropwise to adjust the pH to 3 to 4 to prepare a mixed solution, heat the mixed solution to 70 to 80° C., slowly add 3 to 6 parts of deionized water dropwise over 0.5 to 1 hour, and after the addition is complete, keep the mixture at 70 to 80° C. for 4 to 6 hours, collect the solid by suction filtration, wash with deionized water, and dry at 30 to 40° C. to prepare modified nano-silica;

[0029] S32, pretreating 10-20 parts of microcrystalline cellulose in 150-200 parts of sodium hydroxide solution for 2-3 hours, washing with deionized water, and drying at 30-40°C to obtain pretreated microcrystalline cellulose, adding 10-20 parts of the pretreated microcrystalline cellulose to 200-300 parts of acid hydrolysis solution for acid hydrolysis for 2-3 hours, collecting the colloid by centrifugation, dialyzing with a dialysis bag to a colloid pH of 5-6, freeze-drying at 0-5°C, and grinding to obtain spherical nanocellulose;

[0030] S33. Mix 1 to 3 parts of modified nano-silica and 3 to 5 parts of spherical nano-cellulose by mass to obtain a nano-emulsion stabilizing agent.

[0031] Preferably, the type of microcrystalline cellulose in S32 is any one of PH101, PH102, and PH105, and the acid hydrolysis solution is prepared by mixing 37wt% hydrochloric acid, 98wt% sulfuric acid and deionized water in a mass ratio of 1:2.5~3:6~6.5.

[0032] Preferably, the molecular weight cut-off for dialysis in S32 is 2000-3500 Da.

[0033] A method for preparing a degradable defoaming agent comprises the following steps:

[0034] S1. Mix 10-12 parts of degradable vegetable oleic acid amide, 1-3 parts of diethanolamine laurate, 13-15 parts of polyol fatty acid ester and 0.5-1.5 parts of Tween 80, and ultrasonically disperse for 20-30 minutes to prepare an oil phase;

[0035] S2, adding the remaining amount of Tween 80 and 1-3 parts of nanoemulsion stabilizing agent to 20-50 parts of deionized water to prepare an aqueous phase, adding the aqueous phase to the oil phase at 30-40° C., and homogenizing and emulsifying at a speed of 10000-12000 r / min for 5-10 minutes;

[0036] S3. Cool the system to room temperature, add 20-30 parts of fatty alcohol, adjust the pH of the system to 6-8 with 5-10 wt% sodium hydroxide solution or 5-10 wt% citric acid solution, and package to prepare a biodegradable defoaming agent.

[0037] The present invention also provides an application of a degradable defoaming agent for preparing coating ink, and the preparation method comprises the following steps:

[0038] S41. Mix 30-40 parts by mass of acrylic resin, 7-8 parts by mass of ethanol, and 5-7 parts by mass of deionized water to prepare a solvent. Add 5-10 parts by mass of pigment and defoamer to the solvent, stir and disperse at a speed of 800-1000 r / min for 5-10 minutes, and grind to a fineness of less than 10-15 μm to prepare a base ink.

[0039] S42. Pour 40-50 parts of base ink into a dispersion kettle by mass, add a defoamer into 5-7 parts of deionized water and then add the defoamer into the dispersion kettle, add 8-13 parts of HR830 film-forming emulsion and 15-20 parts of 3,3-dimethacrylate, and stir evenly at a speed of 300-500 r / min to prepare a coating ink.

[0040] Preferably, the defoaming agent in S41 is stirred evenly and then added to the solvent in 2 to 3 portions, with the added amount being 0.2 to 0.5% of the mass of the solvent.

[0041] Preferably, the amount of the defoaming agent added in S42 is 0.2-0.5% of the mass of the base ink.

[0042] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0043] 1. The degradable plant oleic acid amide in the degradable defoamer of the present invention is easily dispersed in liquids, reducing the surface tension of the liquid to achieve a defoaming effect; the polyol fatty acid ester can form insoluble particles to destroy foam; the nanoemulsion stabilizing agent can physically and efficiently defoam by adsorbing gas and has a thickening effect; the fatty alcohol can quickly diffuse to the foam interface, temporarily reducing the local surface tension to achieve a rapid defoaming effect. The degradable defoamer prepared by the present invention has no silicone oil residue, the bio-based ingredients it contains are degradable, and it is environmentally friendly. The fatty alcohol and degradable plant oleic acid amide can instantly defoam, the nanoemulsion stabilizing agent and fatty acid ester can inhibit the regeneration of foam, and diethanolamine laurate and Tween 80 can improve the compatibility and dispersibility of the various components of the defoamer. Through the synergistic effect of the various components, the defoamer has excellent degradability, dispersibility, and anti-foaming properties.

[0044] 2. The present invention prepares vegetable oleic acid methyl ester by reacting vegetable oil with anhydrous methanol, then reacts with 1,4-butanediamine to prepare N-(4-aminobutyl) vegetable oleic acid amide, and finally reacts with an aldose compound to prepare degradable vegetable oleic acid amide. The raw materials are cheap and renewable. The degradable vegetable oleic acid amide has a long alkyl chain and multiple hydroxyl groups, making it easy to disperse in liquids and having excellent defoaming and emulsifying properties.

[0045] 3. The polyol fatty acid ester prepared by the present invention through dehydration and etherification of polyols and then reacting with fatty alcohols is a low-cost renewable raw material with excellent emulsification and dispersibility. When used in defoaming agents, the hydrophilic and hydrophobic groups in its molecular structure can be evenly distributed on the foam surface, thereby destroying the stability of the foam by reducing the surface tension of the foam, preventing foam regeneration and having the ability to suppress foam for a long time.

[0046] 4. The present invention prepares a nano-emulsion stabilizing agent by adding deionized water to anhydrous ethanol through the precipitation of nano-silica by ethyl orthosilicate, and then modifying the obtained modified nano-silica with octadecyltrimethoxysilane and methyltriethoxysilane. The obtained modified nano-silica and spherical nano-cellulose are mixed to obtain a nano-emulsion stabilizing agent having excellent dispersibility and emulsion stability. The octadecyltrimethoxysilane modification makes the modified nano-silica have strong hydrophobicity, can be adsorbed on the oil phase side, and has a thickening effect; the spherical nano-cellulose has hydrophilicity, can be adsorbed on the water phase side, and can form a three-dimensional network structure to stabilize the emulsion through hydrogen bonds; the nano-emulsion stabilizing agent can be used in a defoamer to improve the stability and retention time of the emulsion. DETAILED DESCRIPTION

[0047] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. 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 making any creative efforts are within the scope of protection of the present invention.

[0048] The acrylic resin involved in the embodiments of the present invention is any one of WH-560A and MR1741W, WH-560A is purchased from Jining Tangyi Chemical Co., Ltd., and MR1741W is purchased from Guangdong Keding Functional Materials Co., Ltd.; the pigment is prepared by mixing 85wt% carbon black and 15wt% phthalocyanine blue; HR830 film-forming emulsion is purchased from Guangzhou Houhuan Chemical Additive Co., Ltd.; 3,3-dimethacrylate methyl ester is purchased from Wuhan Kanos Technology Co., Ltd.

[0049] Example 1: A degradable defoamer of this embodiment is prepared from the following components:

[0050] 10g biodegradable vegetable oleic acid amide, 1g diethanolamine laurate, 14g polyol fatty acid ester, 2g nanoemulsion stabilizing agent, 3g Tween 80, 20g fatty alcohol and 50g deionized water.

[0051] The fatty alcohol is lauryl alcohol.

[0052] The preparation method of a degradable defoaming agent of this embodiment comprises the following steps:

[0053] S1. Mix 10 g of biodegradable plant oleic acid amide, 1 g of diethanolamine laurate, 14 g of polyol fatty acid ester and 1.5 g of Tween 80, and disperse them by ultrasonication for 30 min to prepare an oil phase;

[0054] S2, the remaining amount of Tween 80 and 2g of nanoemulsion stabilizing agent were added to 50g of deionized water to prepare an aqueous phase, and the aqueous phase was added to the oil phase at 40°C, and homogenized and emulsified at a speed of 12000r / min for 5min;

[0055] S3. Cool the system to room temperature, add 20 g of fatty alcohol, adjust the pH of the system to 7 with 10 wt % citric acid solution, and package to prepare a biodegradable defoaming agent.

[0056] The preparation method of the degradable vegetable oleic acid amide of this embodiment comprises the following steps:

[0057] S11. Add 100 g of castor oil and 63 g of anhydrous methanol to a reactor by mass, add 1 g of 98 wt % concentrated sulfuric acid, heat to 90° C. and reflux for 6 h, wash with deionized water, allow to stand and separate, collect the organic phase, add 10 g of anhydrous sodium sulfate to remove water, and distill under low pressure to obtain vegetable oleic acid methyl ester;

[0058] S12. By mass, 80 g of vegetable oleic acid methyl ester and 22 g of 1,4-diaminobutane were added to a reactor, 1 g of sodium hydroxide was added, the temperature was raised to 80° C. and the reaction was kept warm for 4 h, and the crude N-(4-aminobutyl) vegetable oleic acid amide was obtained by rotary evaporation under reduced pressure. The crude N-(4-aminobutyl) vegetable oleic acid amide was added to anhydrous ethanol, heated at 50° C. for recrystallization, filtered, and the filtrate was rotary evaporation under reduced pressure to obtain N-(4-aminobutyl) vegetable oleic acid amide;

[0059] S13. According to mass, add 60g of N-(4-aminobutyl) vegetable oleic acid amide and 33g of D-glucose into a reactor, add 250g of methanol, stir until the solid is completely dissolved, heat to 60℃ and react for 2h, cool to room temperature, remove methanol by rotary evaporation, wash with methanol and 75wt% ethanol solution, and dry at 60℃ to obtain degradable vegetable oleic acid amide.

[0060] The preparation method of the polyol fatty acid ester of the present embodiment comprises the following steps:

[0061] S21. Add 91 g of sorbitol by mass to a reactor, add 0.5 g of aluminum trifluoride, stir at 300 r / min for 0.5 h, evacuate the reactor with a vacuum pump, heat to 150° C. and react for 4 h. The hydroxyl value is detected to be 1350 mg KOH / g. Cool to room temperature, collect the supernatant, and obtain an etherified polyol.

[0062] S22. Add 230 g of oleic acid and 1.6 g of p-toluenesulfonic acid to 80 g of etherified polyol by mass, raise the temperature to 60°C and stir at a speed of 500 r / min for 0.5 h, evacuate the reactor to vacuum with a vacuum pump, raise the temperature to 210°C and react until the acid value in the system decreases to 8KOH / g, cool to room temperature, collect the supernatant, and prepare polyol fatty acid ester.

[0063] The preparation method of the nanoemulsion stabilizing agent of this embodiment comprises the following steps:

[0064] S31. By mass, 8 g of ethyl orthosilicate was added to 100 g of anhydrous ethanol, 2 g of octadecyltrimethoxysilane and 1 g of methyltriethoxysilane were added, and 10 wt % dilute hydrochloric acid was added dropwise to adjust the pH to 4 to obtain a mixed solution. The mixed solution was heated to 80° C., and 6 g of deionized water was slowly added dropwise over 1 hour. After the addition was completed, the mixture was kept at 80° C. for 4 hours, and the solid was collected by filtration, washed with deionized water, and dried at 40° C. to obtain modified nano-silica.

[0065] S32, by mass, 10g of PH101 microcrystalline cellulose was placed in 150g of 25wt% sodium hydroxide solution for pretreatment for 2h, washed with deionized water, and dried at 30°C to obtain pretreated microcrystalline cellulose, 10g of the pretreated microcrystalline cellulose was added to 300g of acid hydrolysis solution for acid hydrolysis for 2h, the acid hydrolysis solution was prepared by mixing 37wt% hydrochloric acid, 98wt% sulfuric acid and deionized water in a mass ratio of 1:3:6, and the colloid was collected by centrifugation, the dialysis bag had a molecular weight cutoff of 3500Da, and the dialysis bag was used for dialyzing until the colloid pH was 6, and the cellulose was freeze-dried at 0°C and ground to obtain spherical nanocellulose;

[0066] S33. According to mass, 1 g of modified nano-silica and 3 g of spherical nano-cellulose are mixed to obtain a nano-emulsion stabilizing agent.

[0067] This embodiment also provides an application of a degradable defoaming agent for preparing coating ink, and the preparation method comprises the following steps:

[0068] S41. 300 g of WH-560A acrylic resin, 70 g of ethanol, and 50 g of deionized water were mixed by mass to prepare a solvent. 80 g of pigment and 2 g of defoamer were added to the solvent. The defoamer was stirred and then added to the solvent in two portions. The mixture was stirred and dispersed at a speed of 800 r / min for 5 min, and the mixture was ground to a fineness of less than 15 μm to prepare a base ink.

[0069] S42. Pour 500g of base ink into a dispersion kettle by mass, add 2.5g of defoamer into 50g of deionized water and then add the mixture into the dispersion kettle, add 10g of HR830 film-forming emulsion and 15g of 3,3-dimethacrylate, stir evenly at a speed of 500r / min to prepare a coating ink.

[0070] Example 2: A degradable defoamer of this example is prepared from the following components:

[0071] 10g biodegradable vegetable oleic acid amide, 2g diethanolamine laurate, 15g polyol fatty acid ester, 1g nanoemulsion stabilizing agent, 2g Tween 80, 30g fatty alcohol and 30g deionized water.

[0072] The fatty alcohol is n-decanol.

[0073] The preparation method of a degradable defoaming agent of this embodiment comprises the following steps:

[0074] S1. Mix 10 g of biodegradable plant oleic acid amide, 2 g of diethanolamine laurate, 15 g of polyol fatty acid ester and 1 g of Tween 80, and ultrasonically disperse for 20 min to prepare an oil phase;

[0075] S2. Add the remaining amount of Tween 80 and 1 g of nanoemulsion stabilizing agent to 30 g of deionized water to prepare an aqueous phase, add the aqueous phase to the oil phase at 30° C., and homogenize and emulsify at a speed of 10,000 r / min for 10 min;

[0076] S3. Cool the system to room temperature, add 30 g of fatty alcohol, adjust the pH of the system to 8 with 5 wt % sodium hydroxide solution, and package to prepare a biodegradable defoaming agent.

[0077] This embodiment also provides an application of a degradable defoaming agent for preparing coating ink, and the preparation method comprises the following steps:

[0078] S41. Mix 400 g of MR1741W acrylic resin, 75 g of ethanol, and 50 g of deionized water by mass to prepare a solvent. Add 50 g of pigment and 2 g of defoamer to the solvent. Stir the defoamer until uniform and then add it to the solvent in three portions. Stir and disperse at a speed of 1000 r / min for 5 min. Grind to a fineness of less than 10 μm to prepare a base ink.

[0079] S42. Pour 500g of base ink into a dispersion kettle by mass, add 2g of defoamer into 50g of deionized water and then add the mixture into the dispersion kettle, add 80g of HR830 film-forming emulsion and 150g of 3,3-dimethacrylate, stir evenly at a speed of 500r / min to prepare a coating ink.

[0080] The difference between the degradable plant oleic acid amide of this embodiment and that of Example 1 is that the plant oil is replaced by palm oil, and the aldose compound is replaced by D-mannose.

[0081] The preparation methods of the polyol fatty acid ester and the nanoemulsion stabilizing agent of this embodiment are the same as those in Example 1.

[0082] Example 3: A degradable defoamer of this example is prepared from the following components:

[0083] 12g of degradable vegetable oleic acid amide, 3g of diethanolamine laurate, 13g of polyol fatty acid ester, 3g of nanoemulsion stabilizing agent, 5g of Tween 80, 30g of fatty alcohol and 40g of deionized water.

[0084] The fatty alcohol is n-octanol.

[0085] The preparation method of a degradable defoaming agent of this embodiment comprises the following steps:

[0086] S1. Mix 12 g of degradable vegetable oleic acid amide, 3 g of diethanolamine laurate, 13 g of polyol fatty acid ester and 1.5 g of Tween 80, and ultrasonically disperse for 20 min to prepare an oil phase;

[0087] S2, the remaining amount of Tween 80 and 3g of nanoemulsion stabilizing agent were added to 40g of deionized water to prepare an aqueous phase, and the aqueous phase was added to the oil phase at 35°C, and homogenized and emulsified at a speed of 11000r / min for 5min;

[0088] S3. Cool the system to room temperature, add 30 g of fatty alcohol, adjust the pH of the system to 6 with 5 wt % citric acid solution, and package to prepare a biodegradable defoaming agent.

[0089] This embodiment also provides an application of a degradable defoaming agent for preparing coating ink, and the preparation method comprises the following steps:

[0090] S41. By mass, 350 g of WH-560A acrylic resin, 80 g of ethanol, and 70 g of deionized water were mixed to prepare a solvent. 100 g of pigment and 1 g of defoamer were added to the solvent. The defoamer was stirred evenly and then added to the solvent in two portions. The mixture was stirred and dispersed at a speed of 800 r / min for 5 min, and ground to a fineness of less than 15 μm to prepare a base ink.

[0091] S42. Pour 450g of base ink into a dispersion kettle by mass, add 0.9g of defoamer into 50g of deionized water and then add the mixture into the dispersion kettle, add 130g of HR830 film-forming emulsion and 200g of 3,3-dimethacrylate, stir evenly at a speed of 500r / min to prepare a coating ink.

[0092] The difference between the polyol fatty acid ester of this embodiment and that of embodiment 1 is that the polyol is replaced by xylitol, and the fatty acid is replaced by lauric acid.

[0093] The difference between the nanoemulsion stabilizing agent of this embodiment and that of Example 1 is that the type of microcrystalline cellulose is replaced by PH105.

[0094] The preparation method of the degradable plant oleic acid amide in this embodiment is the same as that in Example 1.

[0095] Comparative Example 1: The difference between this comparative example and Example 1 is that the degradable plant oleic acid amide is replaced by oleic acid diethanolamide.

[0096] Comparative Example 2: This comparative example differs from Example 1 in that no polyol fatty acid ester is added.

[0097] Comparative Example 3: This comparative example differs from Example 1 in that the nanoemulsion stabilizing agent is replaced by nano-silicon dioxide, model HL-200, purchased from Hubei Huifu Nanomaterial Co., Ltd.

[0098] Performance Testing

[0099] 2 g of sodium lauryl sulfate and 2 g of polyoxyethylene lauryl alcohol ether were added to 1 L of deionized water, and the mixture was stirred to obtain a foaming solution.

[0100] Take 50 mL of the foaming solution and shake it up and down 25 times at 25 ° C. Let it stand until the foam height is stable and unchanged, and record it as the initial foam height. Take 0.25 g of the defoaming agent prepared in Examples 1 to 3 and Comparative Examples 1 to 3, respectively, and add it to 50 mL of the foaming solution and start timing. Record the time it takes for the foam of the foaming solution to disappear, that is, the defoaming time. Place the defoamed foaming solution in a shaker and shake it. Record the time it takes for the foam height to reach the initial foam height, that is, the foam suppression time.

[0101] The defoamers prepared in Examples 1 to 3 and Comparative Examples 1 to 3 were sent to a testing agency to test their degradation rates. 10 g of the defoamer was buried in soil 50 cm from the ground surface, and the mass was tested after 3 months. The degradation rate was calculated using the following formula:

[0102]

[0103] δ is the degradation rate,

[0104] m0 is the initial mass of the defoamer, in g,

[0105] m is the mass of the defoamer after being buried in the soil for 3 months, in g.

[0106] The test results are shown in Table 1 below:

[0107] Table 1 Test results

[0108]

[0109] After the defoamers of the examples and comparative examples were used to prepare coating inks, the viscosity of the inks was tested according to GB / T 2794-2013 "Adhesives - Determination of Viscosity - Single Cylinder Viscometer Method"; and the inks were sealed and stored at 50°C for 30 days according to GB / T 6753.3-1986 "Test Method for Storage Stability of Coatings", and the delamination of the inks was tested.

[0110] The coating inks prepared in the examples and comparative examples were applied to an iron plate, naturally air-dried, placed in an oven, heated to 180°C, and dried for 30 minutes. The adhesion grade of the ink was tested according to GB / T 9286-2021 "Paint and varnish cross-cut test". According to GB / T 1733-1993 "Determination of water resistance of paint films", the plate was immersed in deionized water at 100°C for 2 hours, and the adhesion of the ink coating was observed.

[0111] The test results are shown in Table 2 below:

[0112] Table 2 Ink properties

[0113]

[0114] It can be seen from the data in Table 1 that the defoaming time of the defoaming agent prepared in Examples 1 to 3 is 12 to 15 s, and the foam suppression time is 35 to 39 s. The degradable plant oleic acid amide in Comparative Example 1 is replaced with oleic acid diethanolamide, resulting in a decrease in its diffusion rate. Therefore, the defoaming time of Comparative Example 1 is 21 s, and the foam suppression time is 27 s. Comparative Example 2 does not add polyol fatty acid esters, resulting in a decrease in defoaming and foam suppression performance. The defoaming time of Comparative Example 2 is 28 s, and the foam suppression time is 24 s, which shows that the defoaming agent prepared by the present invention has excellent defoaming and foam suppression properties; the degradation rate of the defoaming agent prepared in Examples 1 to 3 is 71.6 to 74.3%, indicating that the defoaming agent prepared by the present invention has excellent degradation performance.

[0115] It can be seen from the data in Table 2 that after the defoaming agents of Examples 1 to 3 are applied to the preparation of coating inks, the viscosity of the inks is between 1.76 and 1.81 Pa·s, and no stratification occurs after sealed storage at 50°C for 30 days, indicating that the defoaming agent prepared by the present invention is applied to the preparation of coating inks, which can improve the storage stability of coating inks. In Comparative Example 3, the nanoemulsion stabilizing agent is replaced with nanosilica, resulting in a decrease in the stability and viscosity of the oil phase, so its viscosity is 1.54 Pa·s, and stratification occurs after sealed storage at 50°C for 30 days; the defoaming agents of Examples 1 to 3 are applied to the preparation of coating inks, and the coating adhesion grade is all level 1. The coating is immersed in deionized water at 100°C for 2 hours without blistering or peeling, indicating that the defoaming agent prepared by the present invention has excellent defoaming and anti-foaming properties, and is applied to coating inks with excellent adhesion and water resistance.

[0116] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

[0117] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to specific embodiments. Obviously, many modifications and variations are possible based on the contents of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A degradable defoamer, characterized in that: It is prepared from the following components in parts by mass: 10-12 parts of degradable vegetable oleic acid amide, 1-3 parts of diethanolamine laurate, 13-15 parts of polyol fatty acid ester, 1-3 parts of nanoemulsion stabilizing agent, 2-5 parts of Tween 80, 20-30 parts of fatty alcohol and 20-50 parts of deionized water; The fatty alcohol is any one of lauryl alcohol, n-octanol, and n-decanol; The preparation method of the degradable plant oleic acid amide comprises the following steps: S11. Add 80-120 parts by mass of vegetable oil and 45-65 parts of anhydrous methanol to a reactor, add 98 wt% concentrated sulfuric acid, heat to 80-90° C. and reflux for 5-6 hours, wash with deionized water, let stand and separate, collect the organic phase, add 5-10 parts of anhydrous sodium sulfate to remove water, and distill under low pressure to obtain vegetable oleic acid methyl ester; S12. Add 80-100 parts of vegetable oleic acid methyl ester and 15-30 parts of 1,4-diamine to a reactor by mass, add 0.5-1 part of an alkali catalyst, raise the temperature to 70-80° C. and keep the reaction for 3-4 hours, and evaporate under reduced pressure to obtain a crude product of N-(4-aminobutyl) vegetable oleic acid amide. Add the crude product of N-(4-aminobutyl) vegetable oleic acid amide to anhydrous ethanol, heat at 40-50° C. for recrystallization, filter, and evaporate the filtrate under reduced pressure to obtain N-(4-aminobutyl) vegetable oleic acid amide; S13. Add 50-80 parts of N-(4-aminobutyl) vegetable oleic acid amide and 30-40 parts of aldose compound into a reactor, add 200-300 parts of methanol, stir until the solid is completely dissolved, heat to 60-70°C and react for 2-3 hours, cool to room temperature, remove methanol by rotary evaporation, wash with methanol and 75-90wt% ethanol solution, and dry at 60-70°C to obtain degradable vegetable oleic acid amide.

2. A degradable defoamer according to claim 1, characterized in that, The vegetable oil in S11 is any one of castor oil, soybean oil and palm oil, and the amount of 98wt% concentrated sulfuric acid added is 1-2% of the mass of the vegetable oil; the alkaline catalyst in S12 is any one of sodium hydroxide and potassium hydroxide; and the aldose compound in S13 is any one of D-glucose, D-mannose and D-galactose.

3. A degradable defoamer according to claim 1, characterized in that, The preparation method of the polyol fatty acid ester comprises the following steps: S21. Add 80-100 parts by mass of polyol to a reactor, add 0.5-0.8 parts of aluminum trifluoride, stir at a speed of 300-500 r / min for 0.5-1 h, evacuate the reactor to a vacuum with a vacuum pump, heat to 150-170° C., react for 3-4 h, test the hydroxyl value to ensure it is qualified, cool to room temperature, collect the supernatant, and obtain an etherified polyol; S22. Add fatty acid and acid catalyst to 80-100 parts of etherified polyol by mass, raise the temperature to 50-60°C and stir at a speed of 300-500 r / min for 0.5-1h, evacuate the reactor to vacuum with a vacuum pump, raise the temperature to 190-230°C and react until the acid value in the system decreases to 7-10KOH / g, cool to room temperature, collect the supernatant, and prepare polyol fatty acid ester.

4. A degradable defoamer according to claim 3, characterized in that, The polyol in S21 is any one of sorbitol, mannitol, and xylitol; the fatty acid in S22 is any one of lauric acid, myristic acid, and oleic acid; the molar ratio of fatty acid to polyol is 1.4~1.6:0.9~1.1, and the amount of acid catalyst added is 0.5~0.8% of the total weight of oleic acid and etherified polyol; the acid catalyst is any one of 98wt% concentrated sulfuric acid, p-toluenesulfonic acid, and phosphoric acid.

5. A degradable defoamer according to claim 1, characterized in that, The preparation method of the nanoemulsion stabilizing agent comprises the following steps: S31. Add 7 to 10 parts of ethyl orthosilicate to 50 to 100 parts of anhydrous ethanol, add 1 to 2 parts of octadecyltrimethoxysilane and 0.5 to 1 part of methyltriethoxysilane, add 5 to 10 wt % of dilute hydrochloric acid dropwise to adjust the pH to 3 to 4 to prepare a mixed solution, heat the mixed solution to 70 to 80° C., slowly add 3 to 6 parts of deionized water dropwise over 0.5 to 1 hour, and after the addition is complete, keep the mixture at 70 to 80° C. for 4 to 6 hours, collect the solid by suction filtration, wash with deionized water, and dry at 30 to 40° C. to prepare modified nano-silica; S32, pretreating 10-20 parts of microcrystalline cellulose in 150-200 parts of sodium hydroxide solution for 2-3 hours, washing with deionized water, and drying at 30-40°C to obtain pretreated microcrystalline cellulose, adding 10-20 parts of the pretreated microcrystalline cellulose to 200-300 parts of acid hydrolysis solution for acid hydrolysis for 2-3 hours, collecting the colloid by centrifugation, dialyzing with a dialysis bag to a colloid pH of 5-6, freeze-drying at 0-5°C, and grinding to obtain spherical nanocellulose; S33. Mix 1 to 3 parts of modified nano-silica and 3 to 5 parts of spherical nano-cellulose by mass to obtain a nano-emulsion stabilizing agent.

6. A degradable defoamer according to claim 5, characterized in that: The model of the microcrystalline cellulose in the S32 is any one of PH101, PH102, and PH105. The acid hydrolysis solution is prepared by mixing 37wt% hydrochloric acid, 98wt% sulfuric acid, and deionized water in a mass ratio of 1:2.5~3:6~6.5, and the dialysis molecular weight cutoff is 2000~3500Da.

7. The method for preparing a degradable defoaming agent according to any one of claims 1 to 6, characterized in that: The steps include: S1. Mix 10-12 parts of degradable vegetable oleic acid amide, 1-3 parts of diethanolamine laurate, 13-15 parts of polyol fatty acid ester and 0.5-1.5 parts of Tween 80, and ultrasonically disperse for 20-30 minutes to prepare an oil phase; S2, adding the remaining amount of Tween 80 and 1-3 parts of nanoemulsion stabilizing agent to 20-50 parts of deionized water to prepare an aqueous phase, adding the aqueous phase to the oil phase at 30-40° C., and homogenizing and emulsifying at a speed of 10000-12000 r / min for 5-10 minutes; S3. Cool the system to room temperature, add 20-30 parts of fatty alcohol, adjust the pH of the system to 6-8 with 5-10 wt% sodium hydroxide solution or 5-10 wt% citric acid solution, and package to prepare a biodegradable defoaming agent.

8. Use of a degradable defoaming agent according to any one of claims 1 to 6, characterized in that: For preparing coating ink, comprising the following steps: S41. Mix 30-40 parts by mass of acrylic resin, 7-8 parts by mass of ethanol, and 5-7 parts by mass of deionized water to prepare a solvent. Add 5-10 parts by mass of pigment and defoamer to the solvent, stir and disperse at a speed of 800-1000 r / min for 5-10 minutes, and grind to a fineness of less than 10-15 μm to prepare a base ink. S42. Pour 40-50 parts of base ink into a dispersion kettle by mass, add a defoamer into 5-7 parts of deionized water and then add the defoamer into the dispersion kettle, add 8-13 parts of HR830 film-forming emulsion and 15-20 parts of 3,3-dimethacrylate, and stir evenly at a speed of 300-500 r / min to prepare a coating ink.

9. The use of a degradable defoaming agent according to claim 8, characterized in that: After being evenly stirred, the defoaming agent in S41 is added to the solvent in 2 to 3 portions, with the added amount being 0.2 to 0.5% of the mass of the solvent; and the added amount of the defoaming agent in S42 is 0.2 to 0.5% of the mass of the base ink.

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