A low-VOC bio-based phenolic resin coating and preparation method thereof

Abstract

The invention discloses a low-VOC bio-based phenolic resin coating and a preparation method thereof, and belongs to the technical field of coatings. The low-VOC bio-based phenolic resin coating of the invention comprises, by weight, raw material components: 30-40 parts by weight of composite water-based phenolic resin, 2-3 parts by weight of triethylamine, 33-37 parts by weight of deionized water, 3-5 parts by weight of ethylene glycol butyl ether, 15-20 parts by weight of pigments and fillers, 0.4-0.7 parts by weight of dispersant, 2.5-3.2 parts by weight of drying agent, and 0.1-0.3 parts by weight of defoamer; the composite water-based phenolic resin is obtained by epoxidation after mixed reaction of rosin-modified phenolic resin, soybean oil acid, glycerol, ethylene glycol butyl ether and a neutralizer; the neutralizer comprises triethylenetetramine and triethylamine.

Description

Technical Field

[0001] The invention relates to a low-VOC bio-based phenolic resin coating and a preparation method thereof. Background Art

[0002] In the context of increasing environmental awareness, reducing volatile organic compound (VOC) emissions has become an important goal of the coatings industry. The large amount of VOC contained in traditional solvent-based coatings is not only harmful to the environment, but also poses a threat to human health. Therefore, the development of low-VOC or VOC-free environmentally friendly coatings has become a research hotspot. Bio-based materials are regarded as ideal alternatives due to their renewable, low carbon footprint and low toxicity.

[0003] Rosin, as a natural resin, comes from the secretions of coniferous trees such as pine trees, and has a rich chemical structure and excellent physical properties. It is mainly composed of rosin acid, which contains a large number of active functional groups in its molecules, such as carboxyl (COOH), hydroxyl (OH) and carbonyl (C=O), which makes rosin easy to react with other chemicals to achieve modification. By combining rosin with phenolic resin, a new type of bio-based composite material, rosin-modified phenolic resin, can be prepared. This modification not only retains the original good mechanical properties and thermal stability of phenolic resin, but also gives the material a lower VOC emission, while increasing its bio-based component ratio, making it more environmentally friendly.

[0004] When rosin is introduced into the molecular structure of phenolic resin, it brings a certain amount of polar groups, such as carboxyl (COOH), hydroxyl (OH) and carbonyl (C=O). The presence of these polar groups increases the interaction between molecules, thereby enhancing the adhesion of the resin and improving its dispersibility for pigments. This is crucial for the application of coatings and inks, because good adhesion and pigment dispersion can ensure that the coating is evenly and firmly attached to the substrate, improving the quality and durability of the coating; on the other hand, the highly rigid multi-ring structure inside the rosin helps to improve the hardness and heat resistance of the modified phenolic resin. However, traditional rosin phenolic resins do have some limitations: they often show high brittleness, inconsistent softening points and other problems, which limit their application in coatings.

[0005] Therefore, the applicant prepared a low VOC bio-based phenolic resin coating. Summary of the invention

[0006] The purpose of the present invention is to provide a low VOC bio-based phenolic resin coating and a preparation method thereof to solve the technical problems mentioned in the above background technology.

[0007] The technical solution for achieving the purpose of the present invention is: a low-VOC bio-based phenolic resin coating, wherein the raw material components include, by weight: 30 to 40 parts by weight of composite water-based phenolic resin, 2 to 3 parts by weight of triethylamine, 33 to 37 parts by weight of deionized water, 3 to 5 parts by weight of ethylene glycol butyl ether, 15 to 20 parts by weight of pigments and fillers, 0.4 to 0.7 parts by weight of dispersant, 2.5 to 3.2 parts by weight of drying agent, and 0.1 to 0.3 parts by weight of defoaming agent.

[0008] Furthermore, the composite water-based phenolic resin is obtained by epoxidation of rosin-modified phenolic resin, soybean oil acid, glycerol, ethylene glycol butyl ether and a neutralizing agent after mixed reaction.

[0009] Furthermore, the neutralizing agent includes triethylenetetramine and triethylamine.

[0010] Furthermore, a method for preparing a low VOC bio-based phenolic resin coating comprises the following preparation steps: Mix 30-40 parts by weight of composite water-based phenolic resin and 2-3 parts by weight of triethylamine, stir at 500-700 r / min for 10-20 min, then add 33-37 parts by weight of deionized water and 3-5 parts by weight of ethylene glycol butyl ether, stir for 10-20 min, then add 15-20 parts by weight of pigments and fillers, 0.4-0.7 parts by weight of dispersants, 2.5-3.2 parts by weight of drying agents, and 0.1-0.3 parts by weight of defoaming agents, stir evenly at a speed of 500-700 r / min, and then disperse at a speed of 1500-2000 r / min for 10-20 minutes, add the slurry to a grinder, grind to a fineness of 30-40 microns, and take it out for use.

[0011] Furthermore, the pigment filler is selected from one or more of titanium dioxide, carbon black, red iron oxide, permanent red, permanent yellow, iron titanium powder, aqueous silver paste, phthalocyanine green, barium sulfate, bentonite, mica iron oxide, sericite, mica powder, nano zinc oxide, diatomaceous earth, quartz sand, and talcum powder.

[0012] Furthermore, the preparation steps of the composite water-based phenolic resin are as follows: under nitrogen protection, 200 parts by mass of rosin-modified phenolic resin are heated to 170-190° C., then 9-11 parts by mass of soybean oil acid are added, and the temperature is kept to react until the acid value is 50-60 mg / gKOH, the temperature is lowered to 115-125° C., 6-10 parts by mass of ethylene glycol butyl ether are added for dilution, 6-8 parts by mass of triethylenetetramine and 1-3 parts by mass of triethylamine are added, and the temperature is raised to The reaction was continued at 140-160° C. for 4-6 hours, then the temperature was raised to 220-240° C. for 7-9 hours, and then the temperature was lowered to 50-60° C., and 9-9.6 parts by weight of a mixed solution of acetic acid and phosphoric acid and 20-24 parts by weight of a 30% hydrogen peroxide solution were simultaneously added dropwise, and the mixture of acetic acid and phosphoric acid was dripped within 30 minutes, and the hydrogen peroxide solution was dripped within 2 hours. The reaction was kept warm for 5.5-6.5 hours, and then cooled to room temperature to obtain a composite water-based phenolic resin.

[0013] Furthermore, the preparation method of the rosin-modified phenolic resin is as follows: 130-150 parts by mass of rosin, 100 parts by mass of bisphenol A, 9-11 parts by mass of dimerized rosin, 65-75 parts by mass of 37% formaldehyde solution, 0.6-0.8 parts by mass of calcium hydroxide, and 0.2-0.4 parts by mass of 25% ammonia water are added into a three-necked flask, heated to melt, then stirred and heated to 170-190° C., kept warm for reaction for 3.5-4.5 hours, then 25-35 parts by mass of glycerol and 0.02-0.04 parts by mass of lithium hydroxide are added, the temperature is raised to 170-190° C., and the reaction is carried out until the acid value is 12-18 mg / gKOH, thereby obtaining the rosin-modified phenolic resin.

[0014] By adopting the above technical solution, the present invention has the following beneficial effects: The low VOC bio-based phenolic resin coating of the present invention comprises, by weight, raw material components: 30-40 parts by weight of composite water-based phenolic resin, 2-3 parts by weight of triethylamine, 33-37 parts by weight of deionized water, 3-5 parts by weight of ethylene glycol butyl ether, 15-20 parts by weight of pigments and fillers, 0.4-0.7 parts by weight of dispersant, 2.5-3.2 parts by weight of drying agent, and 0.1-0.3 parts by weight of defoamer. The composite water-based phenolic resin is obtained by epoxidation after mixed reaction of rosin-modified phenolic resin, soybean oil acid, glycerol, ethylene glycol butyl ether, and a neutralizer; the neutralizer comprises triethylenetetramine and triethylamine.

[0015] The low VOC bio-based phenolic resin coating of the present invention introduces soybean oil acid into the rosin-modified phenolic resin. The long-chain structure of soybean oil acid can play a role similar to a "lubricant" between molecules, reducing the friction between molecular chains, making the polymer network of the entire rosin-modified phenolic resin more flexible, thereby effectively improving the flexibility of the rosin-modified phenolic resin.

[0016] In the reaction process of the composite water-based phenolic resin of the present invention, a neutralizing agent is introduced to adjust the pH value of the composite water-based phenolic resin to ensure the stability of the composite water-based phenolic resin in water. At the same time, the neutralizing agent triethylenetetramine reacts with the oleic acid ester in the composite water-based phenolic resin to form a gemini imidazoline derivative containing soybean oil acid. When used, the gemini imidazoline derivative in the low-VOC bio-based phenolic resin coating coated on the surface has two adsorption centers, which can form a more dense and uniform protective film on the metal surface, provide a better shielding effect, and prevent water, oxygen and other corrosive media from contacting the metal surface. At this time, part of the oleic acid falls off from the rosin-modified phenolic resin, affecting the flexibility of the low-VOC bio-based phenolic resin coating. Subsequently, the gemini imidazoline derivative containing soybean oil acid is epoxidized, and the epoxidized gemini imidazoline derivative is continuously grafted onto the composite water-based phenolic resin by using the epoxy ring opening, thereby ensuring the flexibility of the low-VOC bio-based phenolic resin coating. DETAILED DESCRIPTION

[0017] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with specific implementation methods.

[0018] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without making any creative work shall fall within the scope of protection of the present invention.

[0019] The following embodiments are only used to more clearly illustrate the technical solutions of the present invention, and are not intended to limit the protection scope of the present invention.

[0020] Some of the raw materials of the embodiments and comparative examples are as follows: The pigment and filler are titanium dioxide; the drier is drier 822-1; the dispersant is dispersant BYK2012; and the defoamer is defoamer BYK012.

[0021] (Example 1) A method for preparing a low-VOC bio-based phenolic resin coating comprises the following preparation steps: Mix 30 parts by mass of composite water-based phenolic resin and 2 parts by mass of triethylamine, stir at 500 r / min for 10 min, then add 33 parts by mass of deionized water and 3 parts by mass of ethylene glycol butyl ether, stir for 10 min, then add 15 parts by mass of pigments and fillers, 0.4 parts by mass of dispersant, 2.5 parts by mass of drying agent, and 0.1 parts by mass of defoaming agent, stir evenly at a speed of 500 r / min, and then disperse at a speed of 1500 r / min for 10 minutes. Add the slurry into a grinder and grind it to a fineness of 30 microns, and take it out for use.

[0022] The preparation steps of the composite water-based phenolic resin are as follows: under nitrogen protection, 200 parts by weight of rosin-modified phenolic resin is heated to 170° C., then 9 parts by weight of soybean oil acid is added, the temperature is kept to react until the acid value reaches 50 mg / gKOH, the temperature is lowered to 115° C., 6 parts by weight of ethylene glycol butyl ether is added for dilution, 6 parts by weight of triethylenetetramine and 1 part by weight of triethylamine are added, the temperature is raised to 140° C. and the reaction is continued for 4 hours, the temperature is then raised to 220° C. and the reaction is continued for 7 hours, the temperature is then lowered to 50° C., and 9 parts by weight of a mixed solution of acetic acid and phosphoric acid and 20 parts by weight of a 30% hydrogen peroxide solution are dripped into the mixed solution of acetic acid and phosphoric acid at the same time, the dripping of the mixed solution of acetic acid and phosphoric acid is controlled within 30 minutes, and the dripping of the hydrogen peroxide solution is controlled within 2 hours, the reaction is kept at the temperature for 5.5 hours, and then cooled to room temperature to obtain the composite water-based phenolic resin.

[0023] The preparation method of the rosin-modified phenolic resin is as follows: under nitrogen protection, 130 parts by mass of rosin, 100 parts by mass of bisphenol A, 9 parts by mass of dimerized rosin, 65 parts by mass of 37% formaldehyde solution, 0.6 parts by mass of calcium hydroxide, and 0.2 parts by mass of 25% ammonia water are added into a three-necked flask, heated to melt, then stirred and heated to 170° C., kept warm for reaction for 3.5 hours, then 25 parts by mass of glycerin and 0.02 parts by mass of lithium hydroxide are added, the temperature is raised to 170° C., and the reaction is carried out until the acid value reaches 12 mg / gKOH, thereby obtaining the rosin-modified phenolic resin.

[0024] (Example 2) A method for preparing a low-VOC bio-based phenolic resin coating comprises the following preparation steps: Mix 35 parts by mass of composite water-based phenolic resin and 2.5 parts by mass of triethylamine, stir at 600 r / min for 15 minutes, then add 35 parts by mass of deionized water and 4 parts by mass of ethylene glycol butyl ether, stir for 15 minutes, then add 18 parts by mass of pigments and fillers, 0.6 parts by mass of dispersant, 2.8 parts by mass of drying agent, and 0.2 parts by mass of defoaming agent, stir evenly at a speed of 600 r / min, and then disperse at a speed of 1800 r / min for 15 minutes. Add the slurry into a grinder and grind it to a fineness of 35 microns, and take it out for use.

[0025] The preparation steps of the composite water-based phenolic resin are as follows: under nitrogen protection, 200 parts by weight of rosin-modified phenolic resin is heated to 180° C., then 10 parts by weight of soybean oil acid is added, the temperature is kept to react until the acid value reaches 55 mg / gKOH, the temperature is lowered to 120° C., 8 parts by weight of ethylene glycol butyl ether is added for dilution, 7 parts by weight of triethylenetetramine and 2 parts by weight of triethylamine are added, the temperature is raised to 150° C. and the reaction is continued for 5 hours, the temperature is then raised to 230° C. and the reaction is continued for 8 hours, the temperature is then lowered to 55° C., and 9.3 parts by weight of a mixed solution of acetic acid and phosphoric acid and 22 parts by weight of a 30% hydrogen peroxide solution are dripped into the mixed solution of acetic acid and phosphoric acid at the same time, the dripping of the mixed solution of acetic acid and phosphoric acid is controlled to be completed within 30 minutes, the dripping of the hydrogen peroxide solution is controlled to be completed within 2 hours, the reaction is kept at the temperature for 6 hours, and then cooled to room temperature to obtain the composite water-based phenolic resin.

[0026] The preparation method of the rosin-modified phenolic resin is as follows: under nitrogen protection, 140 parts by mass of rosin, 100 parts by mass of bisphenol A, 10 parts by mass of dimerized rosin, 70 parts by mass of 37% formaldehyde solution, 0.7 parts by mass of calcium hydroxide, and 0.3 parts by mass of 25% ammonia water are added into a three-necked flask, heated to melt, then stirred and heated to 180° C., kept warm for reaction for 4 hours, then 30 parts by mass of glycerin and 0.03 parts by mass of lithium hydroxide are added, the temperature is raised to 180° C., and the reaction is carried out until the acid value reaches 16 mg / gKOH, thereby obtaining the rosin-modified phenolic resin.

[0027] (Example 3) A method for preparing a low-VOC bio-based phenolic resin coating comprises the following preparation steps: Mix 40 parts by mass of composite water-based phenolic resin and 3 parts by mass of triethylamine, stir at 700 r / min for 20 min, then add 37 parts by mass of deionized water and 5 parts by mass of ethylene glycol butyl ether, stir for 20 min, then add 20 parts by mass of pigments and fillers, 0.7 parts by mass of dispersant, 3.2 parts by mass of drying agent, and 0.3 parts by mass of defoaming agent, stir evenly at a speed of 700 r / min, and then disperse at a speed of 2000 r / min for 20 minutes. Add the slurry into a grinder and grind it to a fineness of 40 microns, and take it out for use.

[0028] The preparation steps of the composite water-based phenolic resin are as follows: under nitrogen protection, 200 parts by weight of rosin-modified phenolic resin is heated to 190° C., then 11 parts by weight of soybean oil acid is added, the temperature is kept to react until the acid value reaches 60 mg / gKOH, the temperature is lowered to 125° C., 10 parts by weight of ethylene glycol butyl ether is added for dilution, 8 parts by weight of triethylenetetramine and 3 parts by weight of triethylamine are added, the temperature is raised to 160° C. and the reaction is continued for 6 hours, the temperature is then raised to 240° C. and the reaction is continued for 9 hours, the temperature is then lowered to 60° C., and 9.6 parts by weight of a mixed solution of acetic acid and phosphoric acid and 24 parts by weight of a 30% hydrogen peroxide solution are dripped into the mixed solution of acetic acid and phosphoric acid at the same time, the dripping of the mixed solution of acetic acid and phosphoric acid is controlled to be completed within 30 minutes, and the dripping of the hydrogen peroxide solution is controlled to be completed within 2 hours, the reaction is kept at the temperature for 6.5 hours, and then cooled to room temperature to obtain the composite water-based phenolic resin.

[0029] The preparation method of the rosin-modified phenolic resin is as follows: under nitrogen protection, 150 parts by mass of rosin, 100 parts by mass of bisphenol A, 11 parts by mass of dimerized rosin, 75 parts by mass of 37% formaldehyde solution, 0.8 parts by mass of calcium hydroxide, and 0.4 parts by mass of 25% ammonia water are added into a three-necked flask, heated to melt, then stirred and heated to 190° C., kept warm for reaction for 4.5 hours, then 35 parts by mass of glycerin and 0.04 parts by mass of lithium hydroxide are added, the temperature is raised to 190° C., and the reaction is carried out until the acid value reaches 18 mg / gKOH, thereby obtaining the rosin-modified phenolic resin.

[0030] (Comparative Example 1) A method for preparing a low-VOC bio-based phenolic resin coating comprises the following preparation steps: Mix 35 parts by mass of composite water-based phenolic resin and 2.5 parts by mass of triethylamine, stir at 600 r / min for 15 minutes, then add 35 parts by mass of deionized water and 4 parts by mass of ethylene glycol butyl ether, stir for 15 minutes, then add 18 parts by mass of pigments and fillers, 0.6 parts by mass of dispersant, 2.8 parts by mass of drying agent, and 0.2 parts by mass of defoaming agent, stir evenly at a speed of 600 r / min, and then disperse at a speed of 1800 r / min for 15 minutes. Add the slurry into a grinder and grind it to a fineness of 35 microns, and take it out for use.

[0031] The preparation steps of the composite water-based phenolic resin are as follows: under nitrogen protection, 200 parts by weight of rosin-modified phenolic resin is heated to 180° C., 8 parts by weight of ethylene glycol butyl ether is added for dilution, 7 parts by weight of triethylenetetramine and 2 parts by weight of triethylamine are added, the temperature is raised to 150° C. for continuous reaction for 5 hours, the temperature is then raised to 230° C. for continuous reaction for 8 hours, the temperature is then lowered to 55° C., 9.3 parts by weight of a mixed solution of acetic acid and phosphoric acid and 22 parts by weight of a 30% hydrogen peroxide solution are simultaneously dripped into the mixed solution of acetic acid and phosphoric acid, the dripping of the mixed solution of acetic acid and phosphoric acid is controlled to be completed within 30 minutes, the dripping of the hydrogen peroxide solution is controlled to be completed within 2 hours, the reaction is kept at the temperature for 6 hours, and then cooled to room temperature to obtain the composite water-based phenolic resin.

[0032] The preparation method of the rosin-modified phenolic resin is as follows: under nitrogen protection, 140 parts by mass of rosin, 100 parts by mass of bisphenol A, 10 parts by mass of dimerized rosin, 70 parts by mass of 37% formaldehyde solution, 0.7 parts by mass of calcium hydroxide, and 0.3 parts by mass of 25% ammonia water are added into a three-necked flask, heated to melt, then stirred and heated to 180° C., kept warm for reaction for 4 hours, then 30 parts by mass of glycerin and 0.03 parts by mass of lithium hydroxide are added, the temperature is raised to 180° C., and the reaction is carried out until the acid value reaches 16 mg / gKOH, thereby obtaining the rosin-modified phenolic resin.

[0033] (Comparative Example 2) A method for preparing a low-VOC bio-based phenolic resin coating comprises the following preparation steps: Mix 35 parts by mass of composite water-based phenolic resin and 2.5 parts by mass of triethylamine, stir at 600 r / min for 15 minutes, then add 35 parts by mass of deionized water and 4 parts by mass of ethylene glycol butyl ether, stir for 15 minutes, then add 18 parts by mass of pigments and fillers, 0.6 parts by mass of dispersant, 2.8 parts by mass of drying agent, and 0.2 parts by mass of defoaming agent, stir evenly at a speed of 600 r / min, and then disperse at a speed of 1800 r / min for 15 minutes. Add the slurry into a grinder and grind it to a fineness of 35 microns, and take it out for use.

[0034] The preparation steps of the composite water-based phenolic resin are as follows: under nitrogen protection, 200 parts by weight of rosin-modified phenolic resin is heated to 180° C., then 10 parts by weight of soybean oil acid is added, the temperature is kept to react until the acid value reaches 55 mg / gKOH, the temperature is lowered to 120° C., 8 parts by weight of ethylene glycol butyl ether is added for dilution, 9 parts by weight of triethylamine is added, the temperature is raised to 150° C. and the reaction is continued for 5 hours, the temperature is then raised to 230° C. and the reaction is continued for 8 hours, the temperature is then lowered to 55° C., and 9.3 parts by weight of a mixed solution of acetic acid and phosphoric acid and 22 parts by weight of a 30% hydrogen peroxide solution are dripped into the mixed solution of acetic acid and phosphoric acid at the same time, the dripping of the mixed solution of acetic acid and phosphoric acid is controlled within 30 minutes, the dripping of the hydrogen peroxide solution is controlled within 2 hours, the reaction is kept at the temperature for 6 hours, and then cooled to room temperature to obtain the composite water-based phenolic resin.

[0035] The preparation method of the rosin-modified phenolic resin is as follows: under nitrogen protection, 140 parts by mass of rosin, 100 parts by mass of bisphenol A, 10 parts by mass of dimerized rosin, 70 parts by mass of 37% formaldehyde solution, 0.7 parts by mass of calcium hydroxide, and 0.3 parts by mass of 25% ammonia water are added into a three-necked flask, heated to melt, then stirred and heated to 180° C., kept warm for reaction for 4 hours, then 30 parts by mass of glycerin and 0.03 parts by mass of lithium hydroxide are added, the temperature is raised to 180° C., and the reaction is carried out until the acid value reaches 16 mg / gKOH, thereby obtaining the rosin-modified phenolic resin.

[0036] (Comparative Example 3) A method for preparing a low-VOC bio-based phenolic resin coating comprises the following preparation steps: Mix 35 parts by mass of composite water-based phenolic resin and 2.5 parts by mass of triethylamine, stir at 600 r / min for 15 minutes, then add 35 parts by mass of deionized water and 4 parts by mass of ethylene glycol butyl ether, stir for 15 minutes, then add 18 parts by mass of pigments and fillers, 0.6 parts by mass of dispersant, 2.8 parts by mass of drying agent, and 0.2 parts by mass of defoaming agent, stir evenly at a speed of 600 r / min, and then disperse at a speed of 1800 r / min for 15 minutes. Add the slurry into a grinder and grind it to a fineness of 35 microns, and take it out for use.

[0037] The preparation steps of the composite water-based phenolic resin are as follows: under nitrogen protection, 200 parts by mass of rosin-modified phenolic resin is heated to 180° C., then 10 parts by mass of soybean oil acid is added, the temperature is kept to react until the acid value reaches 55 mg / gKOH, the temperature is lowered to 120° C., 8 parts by mass of ethylene glycol butyl ether is added for dilution, 7 parts by mass of triethylenetetramine and 2 parts by mass of triethylamine are added, the temperature is raised to 150° C. and the reaction is continued for 5 hours, the temperature is then raised to 230° C. and the reaction is continued for 8 hours, and the temperature is cooled to room temperature to obtain the composite water-based phenolic resin.

[0038] The preparation method of the rosin-modified phenolic resin is as follows: under nitrogen protection, 140 parts by mass of rosin, 100 parts by mass of bisphenol A, 10 parts by mass of dimerized rosin, 70 parts by mass of 37% formaldehyde solution, 0.7 parts by mass of calcium hydroxide, and 0.3 parts by mass of 25% ammonia water are added into a three-necked flask, heated to melt, then stirred and heated to 180° C., kept warm for reaction for 4 hours, then 30 parts by mass of glycerin and 0.03 parts by mass of lithium hydroxide are added, the temperature is raised to 180° C., and the reaction is carried out until the acid value reaches 16 mg / gKOH, thereby obtaining the rosin-modified phenolic resin.

[0039] Comparative Example 4 A method for preparing a low-VOC bio-based phenolic resin coating comprises the following preparation steps: Mix 35 parts by mass of composite water-based phenolic resin and 2.5 parts by mass of triethylamine, stir at 600 r / min for 15 minutes, then add 35 parts by mass of deionized water and 4 parts by mass of ethylene glycol butyl ether, stir for 15 minutes, then add 18 parts by mass of pigments and fillers, 0.6 parts by mass of dispersant, 2.8 parts by mass of drying agent, and 0.2 parts by mass of defoaming agent, stir evenly at a speed of 600 r / min, and then disperse at a speed of 1800 r / min for 15 minutes. Add the slurry into a grinder and grind it to a fineness of 35 microns, and take it out for use.

[0040] The preparation steps of the composite water-based phenolic resin are as follows: under nitrogen protection, 200 parts by weight of rosin-modified phenolic resin is heated to 180° C., then 10 parts by weight of soybean oil acid is added, the temperature is kept to react until the acid value reaches 55 mg / gKOH, the temperature is lowered to 120° C., 8 parts by weight of ethylene glycol butyl ether is added for dilution, 7 parts by weight of triethylenetetramine and 2 parts by weight of triethylamine are added, the temperature is then lowered to 55° C., and 9.3 parts by weight of a mixed solution of acetic acid and phosphoric acid and 22 parts by weight of a 30% hydrogen peroxide solution are dripped into the mixed solution of acetic acid and phosphoric acid at the same time, the dripping of the mixed solution of acetic acid and phosphoric acid is controlled within 30 minutes, the dripping of the hydrogen peroxide solution is controlled within 2 hours, the temperature is kept to react for 6 hours, and then the mixture is cooled to room temperature to obtain the composite water-based phenolic resin.

[0041] The preparation method of the rosin-modified phenolic resin is as follows: under nitrogen protection, 140 parts by mass of rosin, 100 parts by mass of bisphenol A, 10 parts by mass of dimerized rosin, 70 parts by mass of 37% formaldehyde solution, 0.7 parts by mass of calcium hydroxide, and 0.3 parts by mass of 25% ammonia water are added into a three-necked flask, heated to melt, then stirred and heated to 180° C., kept warm for reaction for 4 hours, then 30 parts by mass of glycerin and 0.03 parts by mass of lithium hydroxide are added, the temperature is raised to 180° C., and the reaction is carried out until the acid value reaches 16 mg / gKOH, thereby obtaining the rosin-modified phenolic resin.

[0042] Effect example The low VOC bio-based phenolic resin coating prepared in the examples and comparative examples was coated on the surface of the tinplate to form a 30 μm thick paint layer, which was then dried at 80° C. to obtain a corrosion-resistant water-based alkyd paint layer.

[0043] Adhesion grade test: GB / T1720 is used as the reference standard, the cross-cut method is used to test the adhesion of the sample, and the adhesion grade is taken as the test standard.

[0044] Corrosion resistance test: GB / T1771 is used as the reference standard to test the corrosion resistance of low VOC bio-based phenolic resin coatings.

[0045] Flexibility test: GB / T1731 is used as the reference standard to test the flexibility of low VOC bio-based phenolic resin coatings.

[0046] Table 1 below shows the performance results of low VOC bio-based phenolic resin coatings prepared in Examples and Comparative Examples: Table 1

[0047] As shown in Table 1 above, compared with the comparative example, the low VOC bio-based phenolic resin coating prepared in the example has better corrosion resistance, adhesion, storage stability and flexibility.

[0048] Comparison of Comparative Example 1 with Example 2: The rosin-modified phenolic resin in Comparative Example 1 does not use soybean oil acid, and the low-VOC bio-based phenolic resin coating prepared in Example 2 has good corrosion resistance and flexibility.

[0049] Comparative Example 2 is compared with Example 2. In Comparative Example 2, no triethylenetetramine is used as the neutralizer. The low-VOC bio-based phenolic resin coating prepared in Example 2 has good corrosion resistance and adhesion.

[0050] Comparative Example 3 is compared with Example 2. The rosin-modified phenolic resin, soybean oil acid, glycerol, ethylene glycol butyl ether and neutralizer in Comparative Example 3 are not epoxidized after the mixed reaction. The low-VOC bio-based phenolic resin coating prepared in Example 2 has good adhesion and flexibility.

[0051] Comparative Example 4 is compared with Example 2. The composite water-based phenolic resin in Comparative Example 4 is a mixture of rosin-modified phenolic resin, soybean oil acid, glycerin, ethylene glycol butyl ether, and a neutralizer without high-temperature reaction. The low-VOC bio-based phenolic resin coating prepared in Example 2 has good corrosion resistance.

[0052] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A low VOC bio-based phenolic resin coating, characterized in that: The raw material components include, by weight: 30-40 parts by weight of composite water-based phenolic resin, 2-3 parts by weight of triethylamine, 33-37 parts by weight of deionized water, 3-5 parts by weight of ethylene glycol butyl ether, 15-20 parts by weight of pigments and fillers, 0.4-0.7 parts by weight of dispersants, 2.5-3.2 parts by weight of drying agents, and 0.1-0.3 parts by weight of defoaming agents.

2. The low VOC bio-based phenolic resin coating according to claim 1, characterized in that: The composite water-based phenolic resin is obtained by epoxidation after mixed reaction of rosin-modified phenolic resin, soybean oil acid, glycerol, ethylene glycol butyl ether and a neutralizing agent.

3. The low VOC bio-based phenolic resin coating according to claim 1, characterized in that: The neutralizing agent includes triethylenetetramine and triethylamine.

4. A method for preparing a low VOC bio-based phenolic resin coating, characterized in that: The method comprises the following preparation steps: Mix 30-40 parts by weight of composite water-based phenolic resin and 2-3 parts by weight of triethylamine, stir at 500-700 r / min for 10-20 min, then add 33-37 parts by weight of deionized water and 3-5 parts by weight of ethylene glycol butyl ether, stir for 10-20 min, then add 15-20 parts by weight of pigments and fillers, 0.4-0.7 parts by weight of dispersants, 2.5-3.2 parts by weight of drying agents, and 0.1-0.3 parts by weight of defoaming agents, stir evenly at a speed of 500-700 r / min, and then disperse at a speed of 1500-2000 r / min for 10-20 minutes, add the slurry to a grinder, grind to a fineness of 30-40 microns, and take it out for use.

5. The method for preparing a low VOC bio-based phenolic resin coating according to claim 4, characterized in that: The pigment filler is selected from one or more of titanium dioxide, carbon black, red iron oxide, permanent red, permanent yellow, iron titanium powder, aqueous silver paste, phthalocyanine green, barium sulfate, bentonite, mica iron oxide, sericite, mica powder, nano zinc oxide, diatomaceous earth, quartz sand, and talcum powder.

6. The method for preparing a low VOC bio-based phenolic resin coating according to claim 4, characterized in that: The preparation steps of the composite water-based phenolic resin are as follows: under nitrogen protection, 200 parts by weight of rosin-modified phenolic resin is heated to 170-190° C., then 9-11 parts by weight of soybean oil acid is added, the temperature is kept to react until the acid value is 50-60 mg / gKOH, the temperature is lowered to 115-125° C., 6-10 parts by weight of ethylene glycol butyl ether is added for dilution, 6-8 parts by weight of triethylenetetramine and 1-3 parts by weight of triethylamine are added, the temperature is raised to 140-160° C. and the reaction is continued for 4-6 hours, the temperature is then raised to 220-240° C. and the reaction is continued for 7-9 hours, the temperature is then lowered to 50-60° C., 9-9.6 parts by weight of a mixed solution of acetic acid and phosphoric acid and 20-24 parts by weight of a 30% hydrogen peroxide solution are dripped into the mixed solution of acetic acid and phosphoric acid at the same time, the dripping of the mixed solution of acetic acid and phosphoric acid is controlled to be completed within 30 minutes, the dripping of the hydrogen peroxide solution is controlled to be completed within 2 hours, the reaction is kept at the temperature for 5.5-6.5 hours, and then cooled to room temperature to obtain the composite water-based phenolic resin.

7. The method for preparing a low VOC bio-based phenolic resin coating according to claim 6, characterized in that: The preparation method of the rosin-modified phenolic resin is as follows: 130-150 parts by weight of rosin, 100 parts by weight of bisphenol A, 9-11 parts by weight of dimerized rosin, 65-75 parts by weight of 37% formaldehyde solution, 0.6-0.8 parts by weight of calcium hydroxide, and 0.2-0.4 parts by weight of 25% ammonia water are added into a three-necked flask, heated to melt, then stirred and heated to 170-190° C., kept warm for reaction for 3.5-4.5 hours, then added with 25-35 parts by weight of glycerin and 0.02-0.04 parts by weight of lithium hydroxide, heated to 170-190° C., reacted until the acid value was 12-18 mg / gKOH, and obtained the rosin-modified phenolic resin.

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