CN114031758A

CN114031758A - Cottonseed oil water-based alkyd resin and preparation method and application thereof

Info

Publication number: CN114031758A
Application number: CN202111524288.9A
Authority: CN
Inventors: 唐帆; 谢海
Original assignee: Moumou Holding Group Co ltd
Current assignee: Moumou Holding Group Co ltd
Priority date: 2021-12-14
Filing date: 2021-12-14
Publication date: 2022-02-11
Anticipated expiration: 2041-12-14
Also published as: CN114031758B

Abstract

The invention discloses cottonseed oil water-based alkyd resin and a preparation method and application thereof. Taking 35-38% of cottonseed oil, 18-25% of polyalcohol, 7-9% of 2, 2-dimethylolpropionic acid and 32-35% of polybasic acid as reaction raw materials in percentage by weight, taking a water-carrying agent as a reflux solvent, removing the water-carrying agent through reduced pressure distillation after the acid value of a reaction solution is reduced to 25-35 mgKOH/g, adding a cosolvent and a neutralizing agent into the reaction solution, filtering and discharging to obtain the cottonseed oil water-based alkyd resin; in the reaction, the active carbon supported heteropoly acid-ionic liquid is used as a catalyst, and the addition amount of the active carbon supported heteropoly acid-ionic liquid is 0.05-0.1% of the total mass of the reaction raw materials. The cottonseed oil water-based alkyd resin coating not only maintains the basic performance of the alkyd resin coating, but also has good self-drying property, and the coating is light in color, thereby meeting the requirements of the existing coating.

Description

Cottonseed oil water-based alkyd resin and preparation method and application thereof

Technical Field

The invention belongs to the technical field of coatings, and particularly relates to cottonseed oil water-based alkyd resin as well as a preparation method and application thereof.

Background

Alkyd resins are linear resins formed by the polycondensation of a polyol, a polyacid and a monoacid (vegetable oil), also known as monoacid (vegetable oil) -modified polyester resins. Alkyd resins are classified according to the nature of the raw vegetable oil (or fatty acid): drying alkyd resins, semi-drying alkyd resins and non-drying alkyd resins. Because the double bond content of the drying oil molecules is high, the drying alkyd resin synthesized by the drying oil molecules can automatically generate oxidation crosslinking reaction under the air to be dried into a film, and the film is also called as oxidation type alkyd resin. The speed of the semi-drying alkyd resin in the air for crosslinking and film forming is relatively slow, while the non-drying alkyd resin can not be automatically crosslinked and film formed in the air, and cobalt, manganese, lead, zinc and other ions in the drier and hydrogen peroxide are required to form a redox system to reduce the activation energy of hydrogen peroxide decomposition, so that the aim of drying a paint film is fulfilled.

The currently published data show that 1) Rayleigh, Shanxi university of science and technology, and the like, take waste PET bottles, Trimethylolpropane (TMP) and inedible prickly ash seed oil (ZSO) as main raw materials to prepare the PET modified prickly ash seed oil water-based alkyd resin; 2) flax oil-based self-drying water-based alkyd resin is prepared from flax oil, Trimethylolpropane (TMP) and pentaerythritol as main raw materials and lithium hydroxide as a catalyst by Ying of Nanyang agricultural occupational academy; 3) li Zhi Qin, etc. of Xiamen Shuangrui ship paint Limited company takes lithium hydroxide as a catalyst, and soybean oil and TMP are subjected to alcoholysis reaction at the temperature of 240 ℃ to prepare GMA modified waterborne alkyd resin; 4) the Nanjing university of science and technology soup Yang and the like take TMP, linseed oil and epoxy resin (E-44) as main raw materials to prepare epoxy resin modified waterborne alkyd resin; 5) subjecting soybean oil to alcoholysis by TMP (trimethylolpropane) to obtain trimethylolpropane soya-bean oleic acid glycerate, and then subjecting high-solid-content hydroxy acrylic resin to esterification reaction by taking TMA (trimethyl ammonium hydroxide) as a modifier and adding PA (polyamide) as a water-based monomer to prepare a hydroxy acrylic resin modified water-soluble alkyd resin; 6) the Nanyang agriculture academy of profession is a hybrid coating prepared by preparing water-based alkyd resin from soybean oil, neopentyl glycol (NPG), PA, MA, HA, TMP and TMA serving as main raw materials, cold blending the self-prepared water-based alkyd resin with water-based acrylic emulsion HG-100, selecting Ruiko H98 as an anti-flash rust agent and Baxiao S-1440 as a drier.

At present, alkyd resin prepared by taking soybean oil as a raw material is light and flexible in color and lusterThe process is mature, has autoxidation characteristic and is widely loved by the coating industry. In China, the yield and the dosage of cottonseed oil are the first in the world over the years, and the fatty acid composition in the cottonseed oil comprises about 20-25% of palmitic acid, about 2% of stearic acid, about 0.3-0.5% of myristic acid, 0.1-0.6% of arachidic acid, 15-35% of oleic acid and about 35-55% of linoleic acid. Wherein the content of saturated fatty acid is about 25%, the fatty acid is mainly short-chain fatty acid, and C₂₀The above fatty acids only account for about 2%. Because of the fatty acid composition, the soybean oil has natural antioxidant capacity, has less smell compared with other vegetable oils when being heated, has a fatty acid structure composition similar to that of soybean oil, and is a powerful substitute of the soybean oil. For example, chinese patent CN201480051179.1 discloses a coating system comprising 30 to 90 parts by weight of a bio-resin component comprising an acrylic polymer and a bio-polyol formed from a natural oil and 10 to 70 parts by weight of an isocyanate component based on 100 parts by weight of the coating system and having a percent solids of greater than 60%; the natural oil is selected from the group consisting of canola oil, castor oil, coconut oil, cottonseed oil, olive oil, palm oil, peanut oil, rapeseed oil, soybean oil, and combinations thereof. Further, as disclosed in chinese patent CN201980020587.3, a coating composition comprising a thermosetting resin system, said coating composition comprising a mixture of: a thermosetting resin system, graphene nanoplatelets, and a natural or synthetic oil, which is albizzia oil or cottonseed oil.

Based on the current national policy turning to internal circulation and the rapid increase of chemical raw material price, the search for the alternative vegetable oil to prepare alkyd resin is an important means for reducing the cost. The yield and the dosage of the cottonseed oil are the first world in China all the year round, but the cottonseed oil raw material is inferior to the soybean oil: for example, the color of the alkyd resin is dark, and the prepared alkyd resin is too dark to be widely applied to various light-colored types of paint, thereby limiting the application of the alkyd resin.

Although the research in this field is continuously continued, a new idea to improve the color of cottonseed oil water-based alkyd resin is needed.

Disclosure of Invention

1. Problems to be solved

Aiming at the existing problems, the invention aims to provide the cottonseed oil water-based alkyd resin and the preparation method thereof, which can effectively reduce the color depth of the resin so as to meet the use requirement.

The invention also provides an application of the cottonseed oil water-based alkyd resin in a coating.

2. Technical scheme

In order to solve the problems, the technical scheme adopted by the invention is as follows:

the cottonseed oil water-based alkyd resin is prepared by taking 35-38% of cottonseed oil, 18-25% of polyhydric alcohol, 7-9% of 2, 2-dimethylolpropionic acid and 32-35% of polybasic acid in percentage by weight as reaction raw materials, taking a water-carrying agent as a reflux solvent, removing the water-carrying agent through reduced pressure distillation after the acid value of a reaction solution is reduced to 25-35 mgKOH/g, adding a cosolvent and a neutralizing agent into the reaction solution, filtering and discharging to obtain the cottonseed oil water-based alkyd resin; in the reaction, the active carbon supported heteropoly acid-ionic liquid is used as a catalyst, and the addition amount of the active carbon supported heteropoly acid-ionic liquid is 0.05-0.1% of the total mass of the reaction raw materials.

In one possible embodiment of the present invention, the heteropoly acid-ionic liquid is at least one of 1-butyl 3-methylimidazole phosphotungstate, 1- (3-sulfopropyl) pyridine silicotungstate, bis- (3-methyl + -imidazole) butylene phosphomolybdenum vanadate, 1- (3-sulfopropyl) 3-methylimidazole phosphotungstate, and 1-butyl-3-methylimidazole phosphotungstate zincate.

In one possible embodiment of the present invention, the polyhydric alcohol is at least one of ethylene glycol, 1, 3-butanediol, neopentyl glycol, pentaerythritol, diethylene glycol, glycerol, and trimethylolpropane; the polybasic acid is at least one of adipic acid, phthalic anhydride, isophthalic acid and trimellitic anhydride.

In one possible implementation manner of the invention, the addition amount of the water-carrying agent is 10-30% of the total mass of the reaction raw materials; the water-carrying agent is at least one of petroleum ether, benzene, toluene, xylene, cyclohexane, chloroform and carbon tetrachloride.

In one possible embodiment of the present invention, the neutralizing agent is at least one of triethylamine, N-dimethylethanolamine, and ammonia water; the cosolvent is at least one of ethylene glycol butyl ether, propylene glycol monobutyl ether, propylene glycol methyl ether acetate, isopropanol, isobutanol and sec-butanol.

Another object of the present invention is to provide a preparation method of the above-mentioned cottonseed oil water-based alkyd resin, comprising the following steps:

step S101, according to weight percentage: 35-38% of cottonseed oil, 18-25% of polyhydric alcohol, 7-9% of 2, 2-dimethylolpropionic acid and 32-35% of polybasic acid, and preparing reaction raw materials;

step S102, adding reaction raw materials and 0.05-0.1% of activated carbon loaded heteropoly acid-ionic liquid into a reaction flask with a water separator and a reflux condenser pipe, adding 10-30% of water-carrying agent into the reaction flask, stirring and heating to 150-190 ℃ under the protection of nitrogen for esterification reaction for 1-5 h, then heating to 210-240 ℃ and preserving heat for 3-8 h to obtain a reaction solution;

s103, measuring the acid value of the reaction solution, distilling under reduced pressure at the temperature of 140-170 ℃ to remove the water-carrying agent after the acid value of the reaction solution is reduced to 25-35 mgKOH/g, adding a cosolvent and a neutralizing agent into the reaction solution, wherein the adding amount of the cosolvent is 5-25% of the total mass of the reaction raw materials, controlling the pH value of the reaction solution to be 7-8 by using the neutralizing agent, and filtering and discharging to obtain the cottonseed oil water-based alkyd resin.

The preparation principle of the cottonseed oil water-based alkyd resin provided by the invention comprises the following specific processes:

the first step is as follows: alcoholysis reaction

The second step is that: alkyd resin synthesis

The invention also aims to provide the cottonseed oil water-based alkyd resin coating which comprises the following components in parts by weight: 4-6 parts of water, 40-46 parts of cottonseed oil waterborne alkyd resin, 0.2-0.4 part of wetting agent, 0.3-0.5 part of dispersing agent, 0.3-0.4 part of fumed silica, 0.7-1 part of drier, 15-20 parts of titanium dioxide and 5-15 parts of natural barium sulfate.

In one possible embodiment of the invention, the wetting agent is a silicone oil; the dispersant is phosphate dispersant, such as fatty alcohol polyether phosphate, alkylphenol polyether phosphate or aryl phenol polyether phosphate; the drier comprises one or more of metal oxide, metal salt and rare earth drier, wherein the metal is cobalt, manganese, lead, zinc, calcium, iron or zirconium, and the rare earth is cerium.

3. Advantageous effects

Compared with the prior art, the invention has the beneficial effects that:

the cottonseed oil water-based alkyd resin coating disclosed by the invention not only maintains the basic performance of the alkyd resin coating, has good hardness, high film-forming strength and good adhesive force, is not easy to peel, but also has good self-drying property, and in addition, the coating has a light color, and meets the requirements of the existing coating.

Drawings

FIG. 1 schematically shows the structural formula of gossypol;

FIG. 2 schematically shows the preparation process of a cottonseed oil waterborne alkyd.

Detailed Description

The invention is further described with reference to specific examples.

The raw materials used in the following examples were all commercially available unless otherwise specified.

Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements.

The active carbon loaded heteropoly acid-ionic liquid used in the invention is firstly provided with a synthesis method of the heteropoly acid-ionic liquid in the text of 'research progress of heteropoly acid ionic liquid in catalytic organic synthesis reaction' disclosed in Jiangchuntao et al, and the like, and is provided with a heteropoly acid-ionic liquid loading process in consideration of that the loaded heteropoly acid-ionic liquid is mainly a neutral and acidic carrier and in the text of 'research progress of heteropoly acid and salt loading carrier thereof' disclosed in Wangtianli et al, and the carrier is selected from active carbon and SiO₂MCM-41 molecular sieve, ion exchange resin, bentonite, organic high polymer, etc. as traditional carrier including active carbon and SiO₂Most commonly, the heteropoly acid-ionic liquid has the strongest binding force with the heteropoly acid-ionic liquid, and the catalyst has stable structure and high activity.

The esterification reaction of the invention can accelerate the reaction under the action of the catalyst, lead oxide, lithium hydroxide, dibutyltin dilaurate or di-n-butyltin oxide is generally adopted, and the esterification reaction of the invention can also play a role of catalytic reaction by adopting the active carbon supported heteropoly acid-ionic liquid as the catalyst.

Furthermore, the invention adopts cottonseed oil to replace soybean oil to prepare the water-based alkyd resin, however, in the actual production process, although the cottonseed oil replaces part of the soybean oil, the disadvantages of the cottonseed oil are also obvious: because the crude cottonseed oil contains 2-4% of gossypol, phospholipid and pigment, even the refined cottonseed oil still contains 50-100mg/kg of free gossypol (GB/T1537-2019 cottonseed oil), the existing process adopts alkali refining and decoloring to remove oil pigment, if the alkali refining section can not completely remove the gossypol, the residual gossypol and pigment can be denatured in the heating process of decoloring and deodorizing to fix the color of an oil product, so that the color of the cottonseed oil is dark, the prepared alkyd resin has dark color, and cannot be widely applied to various light-color coatings, so that the application of the alkyd resin is limited, and even if the mode of adding other pigments into the coatings is adopted for improvement, the effect is still poor.

On the basis, people firstly think of performing decoloring treatment on cottonseed oil, for example, Sun Jian and the like in the research on a cottonseed oil decoloring process mention that waste argil or attapulgite is used for decoloring; in the 'research and application of decolorant premixed oil decoloring process' by Majian nationality, a premixed decoloring process of premixing activated clay and partial decolored oil and then entering a decoloring tower is proposed. Compared with the prior art, the additional decolorization of the cottonseed oil requires consideration of oil consumption in the decolorization process on one hand, and other impurities may be brought in on the other hand, so that the production requirement cannot be met obviously.

According to a large number of tests and analyses, the inventor directly applies a certain amount of cottonseed oil to the existing coating production system, and adds an activated carbon-supported heteropolyacid-ionic liquid catalyst accounting for 0.05-0.1% of the total mass of reaction raw materials in the reaction process, so that the finally obtained resin and coating have light colors and good effects. The heteropoly acid-ionic liquid is effectively loaded on a porous carrier (active carbon), and the active carbon loaded heteropoly acid-ionic liquid increases the exposed external surface area and the number of reaction active centers of the catalyst.

The inventors analyzed possible reasons to be: the chemical structures of cottonseed oil and soybean oil are similar, as shown in figure 1, under the condition of changing the existing production reaction, gossypol in the cottonseed oil is caused to participate in the reaction by the catalytic action of a catalyst, and most pigments are adsorbed by a porous catalyst, according to the theory of Wiff chromophoric group, the inventor thinks that one end of an unsaturated conjugated chain (such as-C ═ C-, -N ═ N-, -N ═ O and the like) in a chromophoric body of a gossypol molecule is connected with an electron-donating group (such as-OH, -NH ═ O and the like)₂) Or absorbing electron radicals (e.g. -N)O₂、>C ═ O) are attached. The heteropolyacid salt is used for degrading gossypol through photocatalytic oxidation, so that chromophoric groups of the gossypol can be damaged, the gossypol is changed into a small molecular substance without pollution, the color depth of the cottonseed oil is effectively reduced, white pigments and fillers can be used for various light-color coatings in a matched manner, and the application possibility of the cottonseed oil is expanded.

The inventors have also surprisingly found that very small amounts of catechol and its derivatives are found to be present in the final coating system by inspection. The inventors considered that the possible reason is that a part of gossypol in the cottonseed oil can be decomposed into catechol and derivatives thereof by the catalytic decomposition action of the catalyst, and the corresponding catechol and derivatives thereof have antibacterial and antioxidant effects and can enhance the antibacterial and antioxidant effects of the coating.

In addition, because gossypol is denatured and solidified into pigments which are difficult to remove when encountering acidic substances, even if the pigments are decolorized by using waste argil or attapulgite in the prior art, the pigments basically do not work, and on the contrary, the pigments are remained in a resin system to cause color depth, which is not beneficial to subsequent use. Therefore, in the preparation method process of the cottonseed oil waterborne alkyd resin, the cosolvent and the neutralizer are added into the reaction solution, the addition amount of the cosolvent is 5-25% of the total mass of the reaction raw materials, the pH value of the reaction solution is controlled to be 7-8 by the neutralizer, the neutrality of the reaction system is ensured as much as possible, the denaturation and solidification of gossypol are reduced, and the catalysis and decomposition of most gossypol are realized.

The gossypol in the cottonseed oil used by the invention is detected by an HPLC-MS method, and the content of the gossypol in the cottonseed oil is about 3.2 percent by detection.

Example 1

The preparation method of the cottonseed oil water-based alkyd resin of the embodiment comprises the following steps:

step S101, according to weight percentage: 35% of cottonseed oil, 25% of ethylene glycol, 8% of 2, 2-dimethylolpropionic acid and 35% of phthalic anhydride, and preparing reaction raw materials;

step S102, adding reaction raw materials and 0.1% active carbon loaded heteropoly acid-ionic liquid into a reaction flask with a water separator and a reflux condenser tube, adding dimethylbenzene into the reaction flask, stirring and heating to 150 ℃ under the protection of nitrogen to perform esterification reaction for 3 hours, then heating to 240 ℃ and preserving heat for 8 hours to obtain a reaction solution;

and S103, measuring the acid value of the reaction solution, distilling under reduced pressure at the temperature of 170 ℃ to remove xylene after the acid value of the reaction solution is reduced to 35mgKOH/g, adding ethylene glycol butyl ether and triethylamine into the reaction solution, controlling the pH value of the reaction solution to be 7 by using the triethylamine, and filtering and discharging to obtain the cottonseed oil water-based alkyd resin.

Through the preparation process, the obtained cottonseed oil waterborne alkyd resin is detected, and the content of gossypol is about 0.1% by adopting an HPLC-MS method, and almost no color exists; further detection of its components (chromatographic detection) was surprisingly found to be present in very small amounts.

When the cottonseed oil water-based alkyd resin paint is applied to paint, the components of the paint can comprise the following components in parts by weight: 6 parts of water, 46 parts of cottonseed oil water-based alkyd resin, 0.4 part of silicone oil, 0.5 part of fatty alcohol polyether phosphate, 0.4 part of fumed silica, 1 part of metal manganese oxide, 15 parts of titanium dioxide and 15 parts of natural barium sulfate.

When the coating obtained by the embodiment is coated on a sample plate, the whole color of the surface is white, the appearance is smooth, and the use requirement is met.

Example 2

step S101, according to weight percentage: 35% of cottonseed oil, 25% of glycerol, 9% of 2, 2-dimethylolpropionic acid and 30% of isophthalic acid, and preparing reaction raw materials;

step S102, adding reaction raw materials and 0.05% of activated carbon loaded heteropoly acid-ionic liquid into a reaction flask with a water separator and a reflux condenser tube, adding toluene into the reaction flask, stirring and heating to 180 ℃ under the protection of nitrogen to perform esterification reaction for 4 hours, then heating to 210 ℃ and preserving heat for 5 hours to obtain a reaction solution;

and S103, measuring the acid value of the reaction solution, distilling under reduced pressure at the temperature of 150 ℃ to remove toluene after the acid value of the reaction solution is reduced to 30mgKOH/g, adding ethylene glycol butyl ether and triethylamine into the reaction solution, controlling the pH value of the reaction solution to be 8 by controlling the pH value of the reaction solution to be 8, and filtering and discharging to obtain the cottonseed oil water-based alkyd resin.

Through the preparation process, the obtained cottonseed oil waterborne alkyd resin is detected, and the content of gossypol is about 0.08% by adopting an HPLC-MS method, and almost no color exists.

When the cottonseed oil water-based alkyd resin paint is applied to paint, the components of the paint can comprise the following components in parts by weight: 5 parts of water, 45 parts of cottonseed oil water-based alkyd resin, 0.4 part of silicone oil, 0.5 part of dispersing agent, 0.4 part of fumed silica, 1 part of metal cobalt oxide, 15 parts of titanium dioxide and 15 parts of natural barium sulfate.

Example 3

step S101, according to weight percentage: preparing reaction raw materials by using 38% of cottonseed oil, 25% of ethylene glycol, 9% of 2, 2-dimethylolpropionic acid and 35% of phthalic anhydride;

step S102, adding reaction raw materials and the activated carbon loaded heteropoly acid-ionic liquid into a reaction flask with a water separator and a reflux condenser tube, adding dimethylbenzene into the reaction flask, stirring and heating to 150 ℃ under the protection of nitrogen to perform esterification reaction for 3 hours, and then heating to 240 ℃ and preserving heat for 8 hours to obtain a reaction solution;

Through the preparation process, the obtained cottonseed oil waterborne alkyd resin is detected, and the content of gossypol is about 0.12% by adopting an HPLC-MS method, and almost no color exists.

When the cottonseed oil water-based alkyd resin paint is applied to paint, the components of the paint can comprise the following components in parts by weight: 6 parts of water, 46 parts of cottonseed oil water-based alkyd resin, 0.4 part of silicone oil, 0.5 part of aryl phenol polyether phosphate, 0.4 part of fumed silica, 1 part of metal manganese salt, 15 parts of titanium dioxide and 15 parts of natural barium sulfate.

Comparative example 1

This comparative example is essentially the same as example 1 except that no activated carbon-supported heteropolyacid-ionic liquid catalyst is added.

step S102, adding reaction raw materials into a reaction flask with a water separator and a reflux condenser, adding dimethylbenzene into the reaction flask, stirring and heating to 150 ℃ for esterification reaction for 3 hours under the protection of nitrogen, then heating to 240 ℃ and preserving heat for 8 hours to obtain a reaction solution;

Through the preparation process, the obtained cottonseed oil waterborne alkyd resin is detected, and the content of gossypol is found to be about 3.1% by adopting an HPLC-MS method.

When the coating obtained by the comparative example is coated on a sample plate, the whole surface is white and slightly light gray, and the appearance is relatively flat.

In addition, the adhesion test was performed on the brush boards of examples 1 to 3, and a test piece was used in which a cured coating film was formed on a metal board base material by applying an air-jet coating of the aqueous eco-friendly anticorrosive coating composition to the metal board base material and drying (100 ℃ C.. times.10 minutes). Then, the test specimen was examined by the cross-cut method: holding a scribing grid instrument by hand, uniformly applying force on the surface of the dried paint film, and completely scribing the paint film to the surface of a substrate to form a grid pattern; the brush is used for slightly brushing the brush along the diagonal line for a plurality of times, and the cutting edge of the brush plate coating of the embodiment 1-3 is smooth and has no shedding according to the coating stripping result, thereby reaching the adhesive force 0 grade standard and meeting the requirements of the national relevant standards.

The coating of the invention not only needs to meet the performance requirements, but also needs to meet the requirements of national standard (HG/T4759-.

The above description is a more detailed description of the present invention with reference to specific preferred embodiments, and it is not intended to limit the present invention to the specific embodiments described above. It will be apparent to those skilled in the art that various modifications, additions, substitutions, and the like can be made without departing from the spirit of the invention.

Claims

1. 35-38% of cottonseed oil, 18-25% of polyhydric alcohol, 7-9% of 2, 2-dimethylolpropionic acid and 32-35% of polybasic acid are used as reaction raw materials in percentage by weight, a water-carrying agent is used as a reflux solvent, when the acid value of a reaction solution is reduced to 25-35 mgKOH/g, the water-carrying agent is removed through reduced pressure distillation, a cosolvent and a neutralizing agent are added into the reaction solution, and the cottonseed oil water alkyd resin is obtained through filtering and discharging; the method is characterized in that in the reaction, active carbon supported heteropoly acid-ionic liquid is used as a catalyst, and the addition amount of the active carbon supported heteropoly acid-ionic liquid is 0.05-0.1% of the total mass of the reaction raw materials.

2. The cottonseed oil aqueous alkyd resin of claim 1, wherein the heteropoly acid-ionic liquid is at least one of 1-butyl-3-methylimidazole phosphotungstate, 1- (3-sulfopropyl) pyridine silicotungstate, bis- (3-methyl-imidazole) butylene phosphomolybdenum vanadate, 1- (3-sulfopropyl) 3-methylimidazole phosphotungstate, and 1-butyl-3-methylimidazole phosphotungstate zincate.

3. The cottonseed oil water borne alkyd resin of claim 2, wherein the polyol is at least one of ethylene glycol, 1, 3-butanediol, neopentyl glycol, pentaerythritol, diethylene glycol, glycerol, trimethylolpropane; the polybasic acid is at least one of adipic acid, phthalic anhydride, isophthalic acid and trimellitic anhydride.

4. The cottonseed oil aqueous alkyd resin of claim 3, wherein the amount of the water-carrying agent is 10-30% of the total mass of the reaction raw materials; the water-carrying agent is at least one of petroleum ether, benzene, toluene, xylene, cyclohexane, chloroform and carbon tetrachloride.

5. The cottonseed oil water borne alkyd resin of claim 4, wherein the neutralizing agent is at least one of triethylamine, N-dimethylethanolamine, ammonia; the cosolvent is at least one of ethylene glycol butyl ether, propylene glycol monobutyl ether, propylene glycol methyl ether acetate, isopropanol, isobutanol and sec-butanol.

6. A method of preparing the cottonseed oil water borne alkyd resin of claim 1 comprising the steps of:

step S102, adding reaction raw materials and activated carbon loaded heteropoly acid-ionic liquid into a reaction flask with a water separator and a reflux condenser pipe, adding a water-carrying agent into the reaction flask, stirring and heating to 150-190 ℃ under the protection of nitrogen to perform esterification reaction for 1-5 h, then heating to 210-240 ℃ and preserving heat for 3-8 h to obtain a reaction solution;

7. The cottonseed oil water-based alkyd resin coating is characterized by comprising the following components in parts by weight: 4-6 parts of water, 40-46 parts of cottonseed oil waterborne alkyd resin as claimed in claims 1-4, 0.2-0.4 part of wetting agent, 0.3-0.5 part of dispersing agent, 0.3-0.4 part of fumed silica, 0.7-1 part of drier, 15-20 parts of titanium dioxide and 5-15 parts of natural barium sulfate.

8. The cottonseed oil aqueous alkyd coating of claim 7, wherein the wetting agent is a silicone oil; the dispersant is phosphate dispersant; the drier comprises one or more of metal oxide, metal salt and rare earth drier.