阅读说明：本技术 丙烯海松酸改性山梨醇酸树脂的制备方法及采用该方法制得的丙烯海松酸改性山梨醇酸树脂 (Preparation method of acrylpimaric acid modified sorbic acid resin and acrylpimaric acid modified sorbic acid resin prepared by adopting method ) 是由 易争明 谢春弟 于 2020-12-21 设计创作，主要内容包括：本发明提供一种丙烯海松酸改性山梨醇酸树脂的制备方法。所述丙烯海松酸改性山梨醇酸树脂的制备方法包括以下步骤：提供山梨醇、酯化反应、除杂、改性反应。同时本发明还提供一种根据上述制备方法制备得到的丙烯海松酸改性山梨醇酸树脂。本发明的丙烯海松酸改性山梨醇酸树脂具有快干、耐水、硬度高等优点。(The invention provides a preparation method of acrylic pimaric acid modified sorbic acid resin. The preparation method of the acrylpimaric acid modified sorbic acid resin comprises the following steps: sorbitol is provided, esterification reaction, impurity removal and modification reaction are carried out. Meanwhile, the invention also provides the acrylpimaric acid modified sorbic acid resin prepared by the preparation method. The acrylpimaric acid modified sorbic acid resin has the advantages of quick drying, water resistance, high hardness and the like.)

1. The preparation method of the acrylpimaric acid modified sorbic acid resin is characterized by comprising the following steps:

step S01, providing sorbitol: providing a sorbitol aqueous solution, xylene, a stirring device and a temperature control device, wherein the stirring device uniformly mixes the sorbitol aqueous solution and the xylene, the temperature control device heats the sorbitol aqueous solution and the xylene to discharge water in the sorbitol aqueous solution, and the xylene is an azeotropic solvent;

step S02, esterification: providing phthalic anhydride, linoleic acid and an esterification catalyst, and carrying out esterification reaction on the phthalic anhydride, the linoleic acid and the esterification catalyst with the sorbitol obtained in the step S01 to generate the sorbic acid resin;

step S03, impurity removal: removing the xylene in the step S02 esterification reaction to generate the sorbic acid resin, and obtaining the sorbic acid resin after impurity removal;

step S04, modification reaction: providing acrylpimaric acid, and reacting with the sorbic acid resin after impurity removal to obtain the acrylpimaric acid modified sorbic acid resin.

2. The method for preparing acrylpimaric acid-modified sorbic acid resin according to claim 1, further comprising a step S05 of solubilizing: providing propylene glycol methyl ether to the acrylpimaric acid modified sorbic acid resin to improve the stability of the acrylpimaric acid modified sorbic acid resin, wherein the propylene glycol methyl ether is used as a cosolvent.

3. The method for preparing an acrylpimaric acid-modified sorbic acid resin as claimed in claim 2, further comprising a step S06 of adjusting the viscosity: and providing triethylamine, adding the triethylamine into the propylene pimaric acid modified sorbic acid resin added with propylene glycol methyl ether in the step S05, adjusting the viscosity of the propylene pimaric acid modified sorbic acid resin, and improving the hydrophilicity of the propylene pimaric acid modified sorbic acid resin.

4. The method for preparing an acrylpimaric acid-modified sorbic acid resin according to claim 3, further comprising a step S07 of obtaining an aqueous dispersion of an acrylpimaric acid-modified sorbic acid resin: providing distilled water and a high-speed stirring device, discharging the acrylpimaric acid modified sorbic acid resin obtained in the step S06, synchronously adding the distilled water, and synchronously stirring the discharged acrylpimaric acid modified sorbic acid resin and distilled water mixture at high speed by using the high-speed stirring device to obtain the acrylpimaric acid modified sorbic acid resin aqueous dispersion.

5. The method for preparing acrylpimaric acid-modified sorbic acid resin according to claim 4, wherein the amount of the distilled water is such that the aqueous dispersion of acrylpimaric acid-modified sorbic acid resin has a solid content of 40 to 45%.

6. The preparation method of acrylpimaric acid modified sorbic acid resin according to claim 3, wherein the mass percentages of the sorbic acid resin, the acrylpimaric acid and the triethylamine are respectively as follows: 48.53-48.59% of sorbic acid resin, 41.79-41.83% of acrylpimaric acid and 11.29-11.35% of triethylamine.

7. The method for preparing acrylic pimaric acid modified sorbic acid resin according to claim 1, wherein the mass percentages of the linoleic acid, the phthalic anhydride, the sorbitol solution, the xylene and the esterification catalyst are respectively as follows: 33.03-39.96% of linoleic acid, 21.76-37.06% of phthalic anhydride, 36.62-43.12% of sorbitol solution, 4-5% of xylene and 0.5-0.7% of esterification catalyst.

8. The method of claim 7, wherein the esterification catalyst is a mixed catalyst of 0.3% sodium hydroxide and 0.2% phosphorous acid.

9. The method according to claim 1, wherein the purity of the linoleic acid, the aqueous sorbitol solution, and the xylene are all industrial purity, and the purity of the phthalic anhydride, the triethylamine, and the propylene glycol methyl ether are analytical purity.

10. An acrylpimaric acid-modified sorbic acid resin, characterized in that it is prepared by the process according to any one of claims 1 to 9.

Technical Field

The invention relates to the field of resin, and particularly relates to a preparation method of an acrylpimaric acid modified sorbic acid resin.

Background

The alkyd resin has wide application in the aspect of coatings, is applied to various fields of coatings, printing ink, paint, metal protection, vehicles, buildings and the like, is quite familiar with the synthesis technology of the alkyd resin after decades of research, and has the characteristics of high stability, high glossiness, good adhesion and the like. However, in the traditional solvent-based alkyd resin, the volatilization of the organic solvent not only causes burden to the environment, but also threatens the health of users. With the increasing attention on environmental protection and the improvement on the environmental protection requirement of products in China, the research on the water-based alkyd resin is also of great importance. However, the water-based alkyd resin has the defects of slow drying of a coating film, low hardness, poor water resistance, poor adhesion, poor heat resistance and the like, and is modified for improving the performance. The acrylic pimaric acid combines the excellent performances of corrosion resistance, moisture resistance and good adhesiveness of rosin and quick drying, high hardness and the like of acrylic acid, and the waterborne alkyd resin modified by the acrylic pimaric acid has the advantages of the acrylic pimaric acid and the acrylic pimaric acid, and has extremely high research value and development potential.

Disclosure of Invention

The invention provides a preparation method of an acrylpimaric acid modified sorbic acid resin and the acrylpimaric acid modified sorbic acid resin prepared by the method, aiming at solving the problems of slower drying, lower hardness, poorer water resistance and the like of alkyd resins in the prior art.

A preparation method of acrylpimaric acid modified sorbic acid resin comprises the following steps:

step S01, providing a sorbitol aqueous solution, xylene, a stirring device and a temperature control device, wherein the stirring device uniformly mixes the sorbitol aqueous solution and the xylene, the temperature control device heats the sorbitol aqueous solution and the xylene to discharge water in the sorbitol aqueous solution, and the xylene is an azeotropic solvent;

step S02, esterification: providing phthalic anhydride, linoleic acid and an esterification catalyst, and carrying out esterification reaction on the phthalic anhydride, the linoleic acid and the esterification catalyst with the sorbitol obtained in the step S01 to generate the sorbic acid resin;

step S03, impurity removal: removing the xylene in the step S02 esterification reaction to generate the sorbic acid resin, and obtaining the sorbic acid resin after impurity removal;

step S04, modification reaction: providing acrylpimaric acid, and reacting with the sorbic acid resin after impurity removal to obtain the acrylpimaric acid modified sorbic acid resin.

Further, the preparation method of the acrylpimaric acid modified sorbic acid resin further comprises the step S05 of dissolving assisting: providing propylene glycol methyl ether to the acrylpimaric acid modified sorbic acid resin to improve the stability of the acrylpimaric acid modified sorbic acid resin, wherein the propylene glycol methyl ether is used as a cosolvent.

Further, the preparation method of the acrylpimaric acid modified sorbic acid resin further comprises the step S06 of adjusting the viscosity: and providing triethylamine, adding the triethylamine into the propylene pimaric acid modified sorbic acid resin added with propylene glycol methyl ether in the step S05, adjusting the viscosity of the propylene pimaric acid modified sorbic acid resin, and improving the hydrophilicity of the propylene pimaric acid modified sorbic acid resin.

Further, the preparation method of the acrylpimaric acid-modified sorbic acid resin further comprises the step S07 of obtaining the aqueous dispersion of the acrylpimaric acid-modified sorbic acid resin: providing distilled water and a high-speed stirring device, discharging the acrylpimaric acid modified sorbic acid resin obtained in the step S06, synchronously adding the distilled water, and synchronously stirring the discharged acrylpimaric acid modified sorbic acid resin and distilled water mixture at high speed by using the high-speed stirring device to obtain the acrylpimaric acid modified sorbic acid resin aqueous dispersion.

Further, the amount of the distilled water is such that the solid content of the aqueous dispersion of the acrylpimaric acid-modified sorbic acid resin is 40-45%.

Further, the sorbic acid resin, the acrylpimaric acid and the triethylamine are respectively in the following mass percentage: 48.53-48.59% of sorbic acid resin, 41.79-41.83% of acrylpimaric acid and 11.29-11.35% of triethylamine.

Further, the mass percentages of the linoleic acid, the phthalic anhydride, the sorbitol solution, the xylene and the esterification catalyst are respectively as follows: 33.03-39.96% of linoleic acid, 21.76-37.06% of phthalic anhydride, 36.62-43.12% of sorbitol solution, 4-5% of xylene and 0.5-0.7% of esterification catalyst.

Further, the esterification catalyst was a 0.3% sodium hydroxide and 0.2% phosphorous acid mixed catalyst.

Furthermore, the purity of the linoleic acid, the purity of the sorbitol aqueous solution and the purity of the xylene are all industrial purity, and the purity of the phthalic anhydride, the purity of the triethylamine and the purity of the propylene glycol monomethyl ether are analytically pure.

An acrylic pimaric acid modified sorbic acid-alcohol acid resin is prepared from acrylic pimaric acid and sorbic acid-alcohol acid resin.

Compared with the prior art, the acrylic pimaric acid modified sorbic acid resin provided by the invention combines the performances of quick drying, high hardness, corrosion resistance and moisture resistance of rosin, high stability, high glossiness, good adhesion and the like of acrylic acid. So that the alkyd resin has the advantages of quick drying, water resistance, high hardness, high stability, high glossiness, good adhesion and the like.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

Step S01, providing a four-mouth flask with a nitrogen inlet pipe, a stirring device, a thermometer and a condenser pipe and nitrogen, introducing the nitrogen into the four-mouth flask, and enabling the internal environment of the four-mouth flask to be an inert environment so as to reduce the generation of side reactions in organic reactions;

step S02, providing 70% sorbitol aqueous solution and xylene by mass, and adding 65.0g of sorbitol solution and 8.1g of xylene into the four-neck flask;

step S03, stirring the sorbitol aqueous solution and the xylene by the stirring device at the stirring speed of 300 rpm;

step S04, providing a temperature control device, a water separator, phthalic anhydride, linoleic acid and an esterification catalyst, wherein the temperature control device enables the temperature in the bottle of the four-neck flask to rise to 150 ℃ so as to discharge water in the sorbitol aqueous solution;

step S05, adding 37.0g of phthalic anhydride, 73.3g of linoleic acid and 0.5g of esterification catalyst into the four-neck flask for esterification reaction, wherein the temperature control device raises the temperature in the four-neck flask to 180 ℃, keeps the temperature for 1.5 hours, then raises the temperature to 240 ℃ at a constant rate of 1 ℃/min, and keeps the temperature for 4 hours to generate the sorbic acid resin; in the aspect of selecting raw materials, the synthetic sorbic acid resin adopts a fatty acid method and an alcoholysis method, wherein the alcoholysis method uses vegetable oil as a raw material, firstly uses polyalcohol to alcoholyze the vegetable oil, and then generates esterification reaction with other raw materials, the alcoholysis method leads the product components to be complex and difficult to control in the alcoholysis process, and the fatty acid method directly uses fatty acid as the raw material to directly generate esterification reaction with other raw materials, so that the adverse effect caused by alcoholysis can be avoided;

step S06, installing a water separator to a condensation pipe of the four-mouth flask, and removing water generated by the reaction;

step S07, sampling every 30 minutes in the reaction process of keeping the temperature for 4 hours in the step S05, measuring the acid value by using a limonene-ethanol solution, and stopping heating by the temperature control device when the acid value of the system is 7-10 mg KOH/g; the main method for measuring the acid value is a neutralization method, a toluene-ethanol solution is generally used as a solvent, the toluene has high toxicity, and limonene which is a green solvent is selected in an experiment in order to eliminate the pollution of the toluene; the acid value determination comprises the following specific steps: taking about 1.0g of alkyd resin in a 250mL conical flask, adding 50-100 mL of limonene-ethanol solution for dissolving, adding phenolphthalein indicator, and then titrating by using potassium hydroxide-ethanol standard solution until reddish color is not faded for 30s, wherein the calculation formula of the acid value is as follows:

AV＝56.1×c×V/m

wherein, Av is an acid value; c is the concentration (mol/L) of the KOH-ethanol solution, V is the volume (mL) of the KOH solution consumed during titration, and m is the mass (g) of the sample;

step S08, vacuumizing to remove xylene to obtain sorbic acid resin;

step S09, providing acrylpimaric acid, introducing the sorbic acid resin obtained in the step S07 into N2, reducing the temperature in the four-neck flask to 180 ℃ by using the temperature control device, and adding 139.3g of acrylpimaric acid into the four-neck flask for heat preservation reaction to generate acrylpimaric acid sorbic acid resin;

step S10, sampling every 30 minutes in the heat preservation reaction process of step S09, measuring the acid value by using a limonene-ethanol solution, and stopping heating until the acid value is 50-55 mgKOH/g to obtain the acrylpimaric acid modified sorbic acid resin; the main method for measuring the acid value is a neutralization method, a toluene-ethanol solution is generally used as a solvent, the toluene has high toxicity, and limonene which is a green solvent is selected in an experiment in order to eliminate the pollution of the toluene; the acid value determination comprises the following specific steps: taking about 1.0g of alkyd resin in a 250mL conical flask, adding 50-100 mL of limonene-ethanol solution for dissolving, adding phenolphthalein indicator, and then titrating by using potassium hydroxide-ethanol standard solution until reddish color is not faded for 30s, wherein the calculation formula of the acid value is as follows:

AV＝56.1×c×V/m

wherein, Av is an acid value; c is the concentration (mol/L) of the KOH-ethanol solution, V is the volume (mL) of the KOH solution consumed during titration, and m is the mass (g) of the sample;

step S11, providing propylene glycol methyl ether, reducing the temperature of the acrylpimaric acid modified sorbic acid resin obtained in the step S09 to 100 ℃ by a temperature control device, and adding a proper amount of propylene glycol methyl ether to improve the stability of the acrylpimaric acid modified sorbic acid resin; propylene glycol methyl ether is taken as a cosolvent, and compared with other cosolvents, the propylene glycol methyl ether has lower toxicity and better cosolvent effect; the preparation of the alkyd resin generally comprises a solvent method and a melting method, compared with the melting method, the solvent method can reduce raw material loss and better control the composition of the alkyd resin, the required temperature is lower, the color of the synthesized resin is lighter, and the method used in the embodiment is the solvent method;

step S12, providing triethylamine, adding 37.6g of triethylamine to the acrylpimaric acid modified sorbic acid resin obtained in the step S11 when the temperature reaches 60 ℃, stirring and preserving the temperature for 15 minutes, adjusting the viscosity, and improving the hydrophilicity of the acrylpimaric acid modified sorbic acid resin; triethylamine is used as a neutralizing agent, common neutralizing agents comprise ammonia water, N, N-dimethylethanolamine and the like, the neutralizing effect of the triethylamine is better than that of the ammonia water and less than that of the N, N-dimethylethanolamine, but the cost of the N, N-dimethylethanolamine is quite high, and the triethylamine is used as the neutralizing agent in comprehensive consideration;

step S13, providing distilled water and a high-speed stirrer, discharging the substance obtained in the step S11, adding the distilled water into the discharged substance while discharging, and synchronously stirring the discharged acrylpimaric acid modified sorbic acid resin distilled water mixture for 30 minutes at high speed by the high-speed stirrer to obtain an acrylpimaric acid sorbic acid resin water dispersion with the solid content of 40-45%; the solid content calculation formula is as follows:

X＝(W'-W)/G×100％

wherein W is the container mass (G), W' is the sum (G) of the sample and the container mass after baking, and G is the sample mass (G).

Example 2

Step S01, providing a four-mouth flask with a nitrogen inlet pipe, a stirring device, a thermometer and a condenser pipe and nitrogen, introducing the nitrogen into the four-mouth flask, and enabling the internal environment of the four-mouth flask to be an inert environment so as to reduce the generation of side reactions in organic reactions;

step S02, providing 70% sorbitol aqueous solution and xylene by mass, and adding 52.0g of sorbitol solution and 7.6g of xylene into the four-neck flask;

step S03, stirring the sorbitol aqueous solution and the xylene by the stirring device at the stirring speed of 300 rpm;

step S04, providing a temperature control device, a water separator, phthalic anhydride, linoleic acid and an esterification catalyst, wherein the temperature control device enables the temperature in the bottle of the four-neck flask to rise to 150 ℃ so as to discharge water in the sorbitol aqueous solution;

step S05, adding 59.3g of phthalic anhydride, 58.6g of linoleic acid and 0.5g of esterification catalyst into the four-neck flask for esterification reaction, wherein the temperature control device raises the temperature in the four-neck flask to 180 ℃, keeps the temperature for 1.5 hours, then raises the temperature to 240 ℃ at a constant rate of 1 ℃/min, and keeps the temperature for 4 hours to generate the sorbic acid resin; in the aspect of selecting raw materials, the synthetic sorbic acid resin adopts a fatty acid method and an alcoholysis method, wherein the alcoholysis method uses vegetable oil as a raw material, firstly uses polyalcohol to alcoholyze the vegetable oil, and then generates esterification reaction with other raw materials, the alcoholysis method leads the product components to be complex and difficult to control in the alcoholysis process, and the fatty acid method directly uses fatty acid as the raw material to directly generate esterification reaction with other raw materials, so that the adverse effect caused by alcoholysis can be avoided;

step S06, installing a water separator to a condensation pipe of the four-mouth flask, and removing water generated by the reaction;

step S07, sampling every 30 minutes in the reaction process of keeping the temperature for 4 hours in the step S05, measuring the acid value by using a limonene-ethanol solution, and stopping heating by the temperature control device when the acid value of the system is 7-10 mg KOH/g; the main method for measuring the acid value is a neutralization method, a toluene-ethanol solution is generally used as a solvent, the toluene has high toxicity, and limonene which is a green solvent is selected in an experiment in order to eliminate the pollution of the toluene; the acid value determination comprises the following specific steps: taking about 1.0g of alkyd resin in a 250mL conical flask, adding 50-100 mL of limonene-ethanol solution for dissolving, adding phenolphthalein indicator, and then titrating by using potassium hydroxide-ethanol standard solution until reddish color is not faded for 30s, wherein the calculation formula of the acid value is as follows:

AV＝56.1×c×V/m

wherein, Av is an acid value; c is the concentration (mol/L) of the KOH-ethanol solution, V is the volume (mL) of the KOH solution consumed during titration, and m is the mass (g) of the sample;

step S08, vacuumizing to remove xylene to obtain sorbic acid resin;

step S09, providing acrylpimaric acid, introducing the sorbic acid resin obtained in the step S07 into N2, reducing the temperature in the four-neck flask to 180 ℃ by using the temperature control device, and adding 131.1g of acrylpimaric acid into the four-neck flask for heat preservation reaction to generate acrylpimaric acid sorbic acid resin;

step S10, sampling every 30 minutes in the heat preservation reaction process of step S09, measuring the acid value by using a limonene-ethanol solution, and stopping heating until the acid value is 50-55 mgKOH/g to obtain the acrylpimaric acid modified sorbic acid resin; the main method for measuring the acid value is a neutralization method, a toluene-ethanol solution is generally used as a solvent, the toluene has high toxicity, and limonene which is a green solvent is selected in an experiment in order to eliminate the pollution of the toluene; the acid value determination comprises the following specific steps: taking about 1.0g of alkyd resin in a 250mL conical flask, adding 50-100 mL of limonene-ethanol solution for dissolving, adding phenolphthalein indicator, and then titrating by using potassium hydroxide-ethanol standard solution until reddish color is not faded for 30s, wherein the calculation formula of the acid value is as follows:

AV＝56.1×c×V/m

wherein, Av is an acid value; c is the concentration (mol/L) of the KOH-ethanol solution, V is the volume (mL) of the KOH solution consumed during titration, and m is the mass (g) of the sample;

step S11, providing propylene glycol methyl ether, reducing the temperature of the acrylpimaric acid modified sorbic acid resin obtained in the step S09 to 100 ℃ by a temperature control device, and adding a proper amount of propylene glycol methyl ether to improve the stability of the acrylpimaric acid modified sorbic acid resin; propylene glycol methyl ether is taken as a cosolvent, and compared with other cosolvents, the propylene glycol methyl ether has lower toxicity and better cosolvent effect; the preparation of the alkyd resin generally comprises a solvent method and a melting method, compared with the melting method, the solvent method can reduce raw material loss and better control the composition of the alkyd resin, the required temperature is lower, the color of the synthesized resin is lighter, and the method used in the embodiment is the solvent method;

step S12, providing triethylamine, adding 35.4g of triethylamine to the acrylpimaric acid modified sorbic acid resin obtained in the step S11 when the temperature reaches 60 ℃, stirring and keeping the temperature for 15 minutes, adjusting the viscosity, and improving the hydrophilicity of the acrylpimaric acid modified sorbic acid resin; triethylamine is used as a neutralizing agent, common neutralizing agents comprise ammonia water, N, N-dimethylethanolamine and the like, the neutralizing effect of the triethylamine is better than that of the ammonia water and less than that of the N, N-dimethylethanolamine, but the cost of the N, N-dimethylethanolamine is quite high, and the triethylamine is used as the neutralizing agent in comprehensive consideration;

step S13, providing distilled water and a high-speed stirrer, discharging the substance obtained in the step S11, adding the distilled water into the discharged substance while discharging, and synchronously stirring the discharged acrylpimaric acid modified sorbic acid resin distilled water mixture for 30 minutes at high speed by the high-speed stirrer to obtain an acrylpimaric acid sorbic acid resin water dispersion with the solid content of 40-45%; the solid content calculation formula is as follows:

X＝(W^'-W)/G×100％

wherein W is the container mass (G), W' is the sum (G) of the sample and the container mass after baking, and G is the sample mass (G).

Example 3

Step S01, providing a four-mouth flask with a nitrogen inlet pipe, a stirring device, a thermometer and a condenser pipe and nitrogen, introducing the nitrogen into the four-mouth flask, and enabling the internal environment of the four-mouth flask to be an inert environment so as to reduce the generation of side reactions in organic reactions;

step S02, providing 70% sorbitol aqueous solution and xylene by mass, and adding 39.0g of sorbitol solution and 7.8g of xylene into the four-neck flask;

step S03, stirring the sorbitol aqueous solution and the xylene by the stirring device at the stirring speed of 300 rpm;

step S04, providing a temperature control device, a water separator, phthalic anhydride, linoleic acid and an esterification catalyst, wherein the temperature control device enables the temperature in the bottle of the four-neck flask to rise to 150 ℃ so as to discharge water in the sorbitol aqueous solution;

step S05, adding 44.5g of phthalic anhydride, 87.9g of linoleic acid and 0.5g of esterification catalyst into the four-neck flask for esterification reaction, wherein the temperature control device raises the temperature in the four-neck flask to 180 ℃, keeps the temperature for 1.5 hours, then raises the temperature to 240 ℃ at a constant rate of 1 ℃/min, and keeps the temperature for 4 hours to generate the sorbic acid resin; in the aspect of selecting raw materials, the synthetic sorbic acid resin adopts a fatty acid method and an alcoholysis method, wherein the alcoholysis method uses vegetable oil as a raw material, firstly uses polyalcohol to alcoholyze the vegetable oil, and then generates esterification reaction with other raw materials, the alcoholysis method leads the product components to be complex and difficult to control in the alcoholysis process, and the fatty acid method directly uses fatty acid as the raw material to directly generate esterification reaction with other raw materials, so that the adverse effect caused by alcoholysis can be avoided;

step S06, installing a water separator to a condensation pipe of the four-mouth flask, and removing water generated by the reaction;

step S07, sampling every 30 minutes in the reaction process of keeping the temperature for 4 hours in the step S05, measuring the acid value by using a limonene-ethanol solution, and stopping heating by the temperature control device when the acid value of the system is 7-10 mg KOH/g; the main method for measuring the acid value is a neutralization method, a toluene-ethanol solution is generally used as a solvent, the toluene has high toxicity, and limonene which is a green solvent is selected in an experiment in order to eliminate the pollution of the toluene; the acid value determination comprises the following specific steps: taking about 1.0g of alkyd resin in a 250mL conical flask, adding 50-100 mL of limonene-ethanol solution for dissolving, adding phenolphthalein indicator, and then titrating by using potassium hydroxide-ethanol standard solution until reddish color is not faded for 30s, wherein the calculation formula of the acid value is as follows:

AV＝56.1×c×V/m

wherein, Av is an acid value; c is the concentration (mol/L) of the KOH-ethanol solution, V is the volume (mL) of the KOH solution consumed during titration, and m is the mass (g) of the sample;

step S08, vacuumizing to remove xylene to obtain sorbic acid resin;

step S09, providing acrylpimaric acid, introducing the sorbic acid resin obtained in the step S07 into N2, reducing the temperature in the four-neck flask to 180 ℃ by using the temperature control device, and adding 133.6g of acrylpimaric acid into the four-neck flask for heat preservation reaction to generate acrylpimaric acid sorbic acid resin;

step S10, sampling every 30 minutes in the heat preservation reaction process of step S09, measuring the acid value by using a limonene-ethanol solution, and stopping heating until the acid value is 50-55 mgKOH/g to obtain the acrylpimaric acid modified sorbic acid resin; the main method for measuring the acid value is a neutralization method, a toluene-ethanol solution is generally used as a solvent, the toluene has high toxicity, and limonene which is a green solvent is selected in an experiment in order to eliminate the pollution of the toluene; the acid value determination comprises the following specific steps: taking about 1.0g of alkyd resin in a 250mL conical flask, adding 50-100 mL of limonene-ethanol solution for dissolving, adding phenolphthalein indicator, and then titrating by using potassium hydroxide-ethanol standard solution until reddish color is not faded for 30s, wherein the calculation formula of the acid value is as follows:

AV＝56.1×c×V/m

wherein, Av is an acid value; c is the concentration (mol/L) of the KOH-ethanol solution, V is the volume (mL) of the KOH solution consumed during titration, and m is the mass (g) of the sample;

step S11, providing propylene glycol methyl ether, reducing the temperature of the acrylpimaric acid modified sorbic acid resin obtained in the step S09 to 100 ℃ by a temperature control device, and adding a proper amount of propylene glycol methyl ether to improve the stability of the acrylpimaric acid modified sorbic acid resin; propylene glycol methyl ether is taken as a cosolvent, and compared with other cosolvents, the propylene glycol methyl ether has lower toxicity and better cosolvent effect; the preparation of the alkyd resin generally comprises a solvent method and a melting method, compared with the melting method, the solvent method can reduce raw material loss and better control the composition of the alkyd resin, the required temperature is lower, the color of the synthesized resin is lighter, and the method used in the embodiment is the solvent method;

step S12, providing triethylamine, adding 36.1g of triethylamine to the acrylpimaric acid modified sorbic acid resin obtained in the step S11 when the temperature reaches 60 ℃, stirring and keeping the temperature for 15 minutes, adjusting the viscosity, and improving the hydrophilicity of the acrylpimaric acid modified sorbic acid resin; triethylamine is used as a neutralizing agent, common neutralizing agents comprise ammonia water, N, N-dimethylethanolamine and the like, the neutralizing effect of the triethylamine is better than that of the ammonia water and less than that of the N, N-dimethylethanolamine, but the cost of the N, N-dimethylethanolamine is quite high, and the triethylamine is used as the neutralizing agent in comprehensive consideration;

step S13, providing distilled water and a high-speed stirrer, discharging the substance obtained in the step S11, adding the distilled water into the discharged substance while discharging, and synchronously stirring the discharged acrylpimaric acid modified sorbic acid resin distilled water mixture for 30 minutes at high speed by the high-speed stirrer to obtain an acrylpimaric acid sorbic acid resin water dispersion with the solid content of 40-45%; the solid content calculation formula is as follows:

X＝(W^'-W)/G×100％

wherein W is the container mass (G), W' is the sum (G) of the sample and the container mass after baking, and G is the sample mass (G).

Table 1: the quality detection result of the acrylpimaric acid sorbic acid resin is as follows:

the detection method comprises the following steps:

1. and (3) testing water resistance: according to the method specified in GB/T1733-93, a test plate is placed in a water tank, 2/3 with the length of the test plate is soaked in water, the test plate is taken out after a specified time, the water on the surface of the test plate is sucked to be dry by using filter paper, and then whether the paint film has the phenomena of color loss, light loss, wrinkling, foaming, peeling and the like is observed.

2. And (3) testing the adhesive force: the adhesion of the paint films was determined by the cut-out test according to the method specified in GB/T9286-1998. Firstly, a cutter is perpendicular to a test plate, a plurality of scratches with the interval of 1mm are cut on the test plate, and the scratch depth is required to be capable of being scratched to the surface of the test plate; then, the same number of cutting lines intersecting the previous scratch at an angle of 90 degrees are repeatedly cut to form a plurality of small squares with a side length of 1 mm. And (3) sticking a certain length of adhesive tape on the paint film, wherein the direction of the adhesive tape is parallel to one group of scratches, the adhesive tape covers all the squares, and the adhesive tape is rubbed and pressed by fingertips to ensure that the adhesive tape is in good contact with the paint film. One end of the tape was pulled tight and the tape was quickly torn at an angle of 60 degrees, then the paint film was immediately observed with a magnifying glass and the adhesion of the paint film was graded according to the criteria given in the following table.

3. And (3) measuring the hardness of the paint film: according to the method specified in GB/T6739-. Before the pencil is used, the pencil is vertically moved back and forth on abrasive paper, and the tip of the pencil core is ground into a flat and smooth circular section without notches or chippings on the edge. Holding a pencil by hand to enable the pencil lead to form a 45-degree angle with the paint film, then pushing and pressing the pencil lead on the paint film at a constant speed for about 1cm, and observing whether the paint film has obvious scratches; repeatedly scratching each test plate for 5 times by using a pencil with the same type, and if more than 2 obvious scratches appear, reducing the hardness of the pencil for repeated operation until the scratches are less than two; conversely, if the first attempt did not result in more than two distinct scratches, the test was repeated with a pencil having a higher hardness.

As can be seen from Table 1, the acrylic pimaric acid modified sorbic acid resin prepared by the invention has the advantages of quick drying, high hardness, water resistance, high glossiness, good adhesion, high stability and the like compared with the prior art.

The above description is only for three embodiments of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes, which are made by the present specification, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.