阅读说明：本技术 一种基于环氧树脂-丙烯酸树脂的水性醇酸树脂 (Waterborne alkyd resin based on epoxy resin-acrylic resin ) 是由 孙光明 韩红太 王晓庆 孙文俊 段洪东 刘爱君 于 2020-12-27 设计创作，主要内容包括：本申请属于涂料用树脂领域,尤其涉及一种基于环氧树脂-丙烯酸树脂的水性醇酸树脂。该树脂由多元醇50-100份,多元酸40-90份,水性单体10-15份,双酚a型环氧树脂5-7.5份,丙烯酸预聚物40-60份,助溶剂10-20份,中和剂3-6份制备而成；所述的丙烯酸预聚物具体为二醛化合物与三甲基均三嗪聚合后,进一步与甲基丙烯酸甲酯、顺丁烯二酸酐聚合的预聚物。本申请提出的醇酸树脂制备工艺简单,具有较好的市场推广前景。(The application belongs to the field of resin for coating, and particularly relates to waterborne alkyd resin based on epoxy resin-acrylic resin. The resin is prepared from 50-100 parts of polyol, 40-90 parts of polybasic acid, 10-15 parts of water-based monomer, 5-7.5 parts of bisphenol a epoxy resin, 40-60 parts of acrylic prepolymer, 10-20 parts of cosolvent and 3-6 parts of neutralizer; the acrylic prepolymer is polymerized by dialdehyde compound and trimethyl s-triazine, and then further polymerized by methyl methacrylate and maleic anhydride. The alkyd resin provided by the application is simple in preparation process and has a good market popularization prospect.)

1. The waterborne alkyd resin based on the epoxy resin-acrylic resin is characterized by being prepared from the following components in parts by weight:

50-100 parts of polyol, 40-90 parts of polybasic acid, 10-15 parts of water-based monomer, 5-7.5 parts of bisphenol a type epoxy resin, 40-60 parts of acrylic prepolymer, 10-20 parts of cosolvent and 3-6 parts of neutralizer;

The acrylic prepolymer is polymerized by dialdehyde compound and trimethyl s-triazine, and then further polymerized by methyl methacrylate and maleic anhydride.

2. The waterborne alkyd resin of claim 1, wherein the acrylic prepolymer is prepared by the following method:

1) the dialdehyde compound and trimethyl s-triazine are mixed according to a ratio of 3-5: 1 equivalent weight is dissolved in xylene, the reaction is stopped after Lewis base reacts for 8 to 12 hours at the temperature of between 60 and 100 ℃, and the Lewis base is removed by filtration;

2) adding methyl methacrylate and maleic anhydride into the filtrate system obtained in the step 1), introducing nitrogen for 20-30min, adding an initiator, reacting at 170-180 ℃ for 2-5h, and fractionating xylene in the reaction process to obtain the acrylic prepolymer.

3. The waterborne alkyd resin of claim 2, wherein said lewis base is selected from the group consisting of potassium hydroxide, sodium hydroxide; the molar ratio of the Lewis base to the trimethyl s-triazine is 2: 3.

4. the waterborne alkyd resin of claim 2, wherein said dialdehyde compound has the formula of OHC- (CH) ₂)_n-CHO said n is selected from 2, 3, 4, 5, 6.

5. The waterborne alkyd resin of claim 2, wherein said methyl methacrylate and trimethyl s-triazine are present in a molar ratio of 12 to 20: 1.

6. the waterborne alkyd resin of claim 2, wherein the molar ratio of methyl methacrylate to maleic anhydride is from 1 to 1.2: 1.

7. the method for preparing the epoxy resin-acrylic resin double-modified waterborne alkyd resin coating according to claim 1, is characterized by comprising the following steps:

1) preheating an acrylic prepolymer to 70-80 ℃, adding bisphenol A epoxy resin, a catalyst (0.01-1 wt% of tetraethylammonium bromide), a polymerization inhibitor (0.01-1 wt% of 2, 6-di-tert-butyl-p-cresol) into the acrylic prepolymer, heating to 80-110 ℃, and stopping reaction when the temperature is kept for reaction until the acid value is lower than 6mgKOH/g, thereby obtaining acrylic modified bisphenol A epoxy resin;

2) adding polybasic acid, polyalcohol and water-based monomer into a reaction kettle according to a given ratio, and stopping reaction at 180-230 ℃ until the acid value is 3-10mg KOH/g;

3) adding the product obtained in the step 1) into the step 2), adding a cosolvent, and reacting for 5-6h at the temperature of 50-80 ℃;

4) Cooling to 50 ℃, adding a neutralizing agent, reacting for 30-40min under the condition of heat preservation, adding deionized water, adjusting the solid content to 80-95%, and discharging.

8. The method of claim 7, wherein the polyol is selected from the group consisting of pentaerythritol and sorbitol in a hydroxyl content equivalent ratio of 1: 1.

Technical Field

The application belongs to the field of resin for coating, and particularly relates to waterborne alkyd resin based on epoxy resin-acrylic resin.

Background

Alkyd resins are resins that are polymerized from polyols, polybasic acids, and fatty acids by esterification reactions. Because the raw materials are cheap and easy to obtain, the paint film has high drying speed and excellent luster, hardness and durability, and has important position in the paint industry.

The steel structure construction is the construction means commonly used at present, because the phenomenon such as corrodes in the rainwater in order to reduce the steel construction, need spray paint on steel structure surface to the contact of separation steel and external world. The water-based alkyd resin coating has the advantage of environmental protection and is beneficial to water solubility, and is often selected to be applicable as steel structure finish paint. In the paint spraying construction of the surface of a steel structure, the problems that the thickness of a single spraying coating can not meet the requirement and multiple spraying is needed exist, and the construction efficiency is influenced. The steel structure surface is smooth, and the coating is required to have higher adhesive force. In addition, the steel structure finish paint is usually constructed outdoors, and the spraying construction effect can be seriously damaged if the steel structure finish paint meets rainwater weather in a short time, so that the steel structure finish paint has better water resistance.

Based on the current situation, designing and developing a novel water-based alkyd resin for the surface of a steel structure is a problem to be solved urgently.

Disclosure of Invention

In order to solve the problems, the application provides an epoxy resin-acrylic resin-based waterborne alkyd resin, which utilizes a multi-branched s-triazine derivative to modify a copolymer of acrylic acid and maleic anhydride, then utilizes the prepolymer to modify a double-part A epoxy resin, and utilizes carboxyl on an acrylic prepolymer to perform esterification reaction with hydroxyl in a bisphenol A epoxy resin so as to combine the bisphenol A epoxy resin with the acrylic prepolymer. And (4) the combination is further participated in the synthesis of the alkyd resin, and the alkyd resin is finally prepared. The nitrogen-containing compound is grafted in the acrylic resin to improve the high-temperature resistance of the coating; the polybasic compound is grafted in the acrylic acid to improve the molecular weight of the resin in the finish paint, so that the water resistance of the initial paint is good. The alkyd resin provided by the application is simple in preparation process and has a good market popularization prospect.

In order to achieve the purpose, the technical scheme adopted by the application is as follows:

the waterborne alkyd resin based on the epoxy resin-acrylic resin is prepared from the following components in parts by weight:

50-100 parts of polyol, 40-90 parts of polybasic acid, 10-15 parts of water-based monomer, 5-7.5 parts of bisphenol a type epoxy resin, 40-60 parts of acrylic prepolymer, 10-20 parts of cosolvent and 3-6 parts of neutralizer;

the acrylic prepolymer is polymerized by dialdehyde compound and trimethyl s-triazine, and then further polymerized by methyl methacrylate and maleic anhydride.

Said trimethyl-s-triazine is synthesized according to the methods described in document h.g.elias, e.greth, Die Makromolekulare Chemie,1969,123, 203;

the preparation method of the acrylic prepolymer comprises the following steps:

1) the dialdehyde compound and trimethyl s-triazine are mixed according to a ratio of 3-5: 1 equivalent weight is dissolved in xylene, the reaction is stopped after Lewis base reacts for 8 to 12 hours at the temperature of between 60 and 100 ℃, and the Lewis base is removed by filtration;

2) adding methyl methacrylate and maleic anhydride into the filtrate system obtained in the step 1), introducing nitrogen for 20-30min, adding an initiator, reacting at 170-180 ℃ for 2-5h, and fractionating xylene in the reaction process to obtain an acrylic prepolymer;

The Lewis base is selected from potassium hydroxide and sodium hydroxide; the molar ratio of the Lewis base to the trimethyl s-triazine is 2: 3;

the initiator is BPO, and the dosage of the initiator accounts for 0.1-0.015 percent of the total mass of the system;

the dialdehyde compound has a general formula of OHC-R-CHO, wherein R is C2-C6 straight-chain alkyl;

the molar ratio of the methyl methacrylate to the trimethyl s-triazine is 12-20: 1;

the molar ratio of the methyl methacrylate to the maleic anhydride is 1-1.2: 1;

when a dialdehyde compound reacts with trimethyl s-triazine, methyl reacts with aldehyde group to form C ═ C, 3 methyl groups on the trimethyl s-triazine are uniformly dispersed, and three branched chains are connected with alkyl chains to form a multi-branched structure; and then, when methyl methacrylate and maleic anhydride are dripped into the system, the double bond of acrylic acid or anhydride and the double bond formed by the aldehyde group and the methyl carry out free radical polymerization to obtain the acrylic acid prepolymer. The acrylic prepolymer is reacted with bisphenol a epoxy resin and the carboxyl groups in the prepolymer are reacted with the epoxy groups in the epoxy resin to combine the epoxy resin and the acrylic prepolymer. Therefore, acrylic prepolymer with larger molecular weight is grafted on the epoxy resin chain, so that the polarity of the epoxy resin is improved. When the modified epoxy resin participates in the alkyd reaction, a branched chain structure with larger molecular weight is introduced on the long chain esterified by the alkyd, so that the polarity of the macromolecule is improved, the cohesive force of the macromolecule is reduced, the wetting property of the macromolecule is improved, the van der Waals force between the resin and the steel surface is improved, and the adhesive force on the steel structure surface is increased.

On the other hand, the nitrogen atom on the triazine ring has lone pair electrons, and can form covalent bonds with metal ions on the surface of steel, so that the adhesive force of the coating is increased to a certain extent.

The preparation method of the epoxy resin-acrylic resin double-modified waterborne alkyd resin coating specifically comprises the following steps:

1) preheating an acrylic prepolymer to 70-80 ℃, adding bisphenol A epoxy resin, a catalyst (0.01-1 wt% of tetraethylammonium bromide), a polymerization inhibitor (0.01-1 wt% of 2, 6-di-tert-butyl-p-cresol) into the acrylic prepolymer, heating to 80-110 ℃, and stopping reaction when the temperature is kept for reaction until the acid value is lower than 6mgKOH/g, thereby obtaining acrylic modified bisphenol A epoxy resin;

2) adding polybasic acid, polyalcohol and water-based monomer into a reaction kettle according to a given ratio, and stopping reaction at 180-230 ℃ until the acid value is 3-10mg KOH/g;

3) adding the product obtained in the step 1) into the step 2), adding a cosolvent, and reacting for 5-6h at the temperature of 50-80 ℃;

4) cooling to 50 ℃, adding a neutralizing agent, reacting for 30-40min under the condition of heat preservation, adding deionized water, adjusting the solid content to 80-95%, and discharging.

The polyalcohol is selected from a complex of pentaerythritol and sorbitol, and the equivalent ratio of hydroxyl content of the polyalcohol to the sorbitol is 1: 1;

The polybasic acid is selected from soybean oil fatty acid, the acid value is 198-204mgKOH/g, and the iodine value is 120-125 mgKOH/g;

the bisphenol A type epoxy resin is E20 bisphenol A type epoxy resin;

the water-based monomer is selected from trimellitic anhydride;

the cosolvent is selected from isopropanol;

the neutralizing agent is selected from N, N-dimethylethanolamine;

the technology introduces the acrylic prepolymer, and improves the dispersion performance of the coating through hyperbranched modification; the introduction of trimethyl s-triazine improves the content of nitrogen element, and the corrosion resistance is further improved; in addition, the hyperbranched acrylic prepolymer is introduced, so that the molecular weight distribution of the polymer is improved, and the water resistance of the initial paint is effectively improved; dialdehyde compounds are used in the prepolymer, and alkyl chains are introduced, so that the polymer is stable and is not easy to decompose under the conditions of illumination and the like.

Detailed Description

Example 1

The waterborne alkyd resin based on the epoxy resin-acrylic resin is prepared from the following components in parts by weight:

50-100 parts of polyol, 40-90 parts of polybasic acid, 10-15 parts of water-based monomer, 5-7.5 parts of bisphenol a type epoxy resin, 40-60 parts of acrylic prepolymer, 10-20 parts of cosolvent and 3-6 parts of neutralizer;

the acrylic prepolymer is polymerized by dialdehyde compound and trimethyl s-triazine, and then further polymerized by methyl methacrylate and maleic anhydride.

The preparation method of the acrylic prepolymer comprises the following steps:

1) the dialdehyde compound and trimethyl s-triazine are mixed according to a ratio of 3-5: 1 equivalent weight is dissolved in xylene, the reaction is stopped after Lewis base reacts for 8 to 12 hours at the temperature of between 60 and 100 ℃, and the Lewis base is removed by filtration;

2) adding methyl methacrylate and maleic anhydride into the filtrate system obtained in the step 1), introducing nitrogen for 20-30min, adding an initiator, reacting at 170-180 ℃ for 2-5h, and fractionating xylene in the reaction process to obtain an acrylic prepolymer;

the Lewis base is selected from potassium hydroxide and sodium hydroxide; the molar ratio of the Lewis base to the trimethyl s-triazine is 2: 3;

the initiator is BPO, and the dosage of the initiator accounts for 0.1-0.015 percent of the total mass of the system;

the dialdehyde compound has the general formula of OHC- (CH)₂)₂-CHO said n being selected from 2, 3, 4, 5, 6;

the molar ratio of the methyl methacrylate to the trimethyl s-triazine is 12-20: 1;

the molar ratio of the methyl methacrylate to the maleic anhydride is 1-1.2: 1;

the preparation method of the epoxy resin-acrylic resin double-modified waterborne alkyd resin coating specifically comprises the following steps:

1) preheating an acrylic prepolymer to 70-80 ℃, adding E20 bisphenol A epoxy resin, a catalyst (0.01-1 wt% of tetraethylammonium bromide), a polymerization inhibitor (2, 6-di-tert-butyl-p-cresol/0.01-1 wt%) into the acrylic prepolymer, heating to 80-110 ℃, and stopping reaction when the acid value is lower than 6mgKOH/g through heat preservation reaction to obtain acrylic modified bisphenol A epoxy resin;

2) Adding polybasic acid, polyalcohol and trimellitic anhydride into a reaction kettle according to a given ratio, and stopping reaction at 180-230 ℃ until the acid value is 3-10mg KOH/g;

3) adding the product obtained in the step 1) into the step 2), adding a cosolvent, and reacting for 5-6h at the temperature of 50-80 ℃;

4) cooling to 50 ℃, adding a neutralizing agent, reacting for 30-40min under the condition of heat preservation, adding deionized water, adjusting the solid content to 80-95%, and discharging.

The polyalcohol is selected from a complex of pentaerythritol and sorbitol, and the equivalent ratio of hydroxyl content of the polyalcohol to the sorbitol is 1: 1;

the polybasic acid is selected from soybean oil fatty acid, the acid value is 198-204mgKOH/g, and the iodine value is 120-125 mgKOH/g;

example 2

The waterborne alkyd resin based on the epoxy resin-acrylic resin is prepared from the following components in parts by weight:

50 parts of polyol, 40 parts of polybasic acid, 10 parts of water-based monomer, 5 parts of bisphenol a epoxy resin, 40 parts of acrylic prepolymer, 10 parts of cosolvent and 3 parts of neutralizer;

the acrylic prepolymer is polymerized by dialdehyde compound and trimethyl s-triazine, and then further polymerized by methyl methacrylate and maleic anhydride.

The preparation method of the acrylic prepolymer comprises the following steps:

1) Dialdehyde compound and trimethyl s-triazine are mixed according to a ratio of 3: 1 equivalent weight, dissolved in xylene, reacted for 8 hours at 60 ℃ with lewis base, and filtered to remove lewis base;

2) adding methyl methacrylate and maleic anhydride into the filtrate system obtained in the step 1), introducing nitrogen for 20min, adding an initiator, reacting at 170 ℃ for 2-5h, and fractionating xylene in the reaction process to obtain an acrylic prepolymer;

the Lewis base is selected from potassium hydroxide and sodium hydroxide; the molar ratio of the Lewis base to the trimethyl s-triazine is 2: 3;

the initiator is BPO, and the dosage of the initiator accounts for 0.1-0.015 percent of the total mass of the system;

the dialdehyde compound has the general formula of OHC- (CH)₂)₂-CHO；

The molar ratio of the methyl methacrylate to the trimethyl s-triazine is 12: 1;

the molar ratio of the methyl methacrylate to the maleic anhydride is 1: 1;

the preparation method of the epoxy resin-acrylic resin double-modified waterborne alkyd resin coating specifically comprises the following steps:

1) preheating an acrylic prepolymer to 70 ℃, adding E20 bisphenol A epoxy resin, a catalyst (0.01-1 wt% of tetraethylammonium bromide), a polymerization inhibitor (2, 6-di-tert-butyl-p-cresol/0.01-1 wt%) into the acrylic prepolymer, heating to 80-110 ℃, and stopping reaction when the acid value is lower than 6mgKOH/g through heat preservation reaction to obtain acrylic modified bisphenol A epoxy resin;

2) Adding polybasic acid, polyalcohol and trimellitic anhydride into a reaction kettle according to a given ratio, and stopping reaction at 200 ℃ until the acid value is 6mg KOH/g;

3) adding the product obtained in the step 1) into the step 2), adding a cosolvent, and reacting for 5-6h at the temperature of 50-80 ℃;

4) cooling to 50 ℃, adding a neutralizing agent, reacting for 30-40min under the condition of heat preservation, adding deionized water, adjusting the solid content to 80%, and discharging.

The polyalcohol is selected from a complex of pentaerythritol and sorbitol, and the equivalent ratio of hydroxyl content of the polyalcohol to the sorbitol is 1: 1;

the polybasic acid is selected from soybean oil fatty acid, the acid value is 198-204mgKOH/g, and the iodine value is 120-125 mgKOH/g;

example 3

The waterborne alkyd resin based on the epoxy resin-acrylic resin is prepared from the following components in parts by weight:

100 parts of polyol, 90 parts of polybasic acid, 15 parts of water-based monomer, 5-7.5 parts of bisphenol a type epoxy resin, 60 parts of acrylic prepolymer, 20 parts of cosolvent and 6 parts of neutralizer;

the acrylic prepolymer is polymerized by dialdehyde compound and trimethyl s-triazine, and then further polymerized by methyl methacrylate and maleic anhydride.

The preparation method of the acrylic prepolymer comprises the following steps:

1) Dialdehyde compound and trimethyl s-triazine were mixed according to 5: 1 equivalent weight, dissolved in xylene, reacted for 12h at 100 ℃ with lewis base, and filtered to remove lewis base;

2) adding methyl methacrylate and maleic anhydride into the filtrate system obtained in the step 1), introducing nitrogen for 30min, adding an initiator, reacting at 180 ℃ for 5h, and fractionating xylene in the reaction process to obtain an acrylic prepolymer;

the Lewis base is selected from potassium hydroxide and sodium hydroxide; the molar ratio of the Lewis base to the trimethyl s-triazine is 2: 3;

the initiator is BPO, and the dosage of the initiator accounts for 0.1-0.015 percent of the total mass of the system;

the dialdehyde compound has the general formula of OHC- (CH)₂)₆-CHO；

The molar ratio of the methyl methacrylate to the trimethyl s-triazine is 20: 1;

the molar ratio of the methyl methacrylate to the maleic anhydride is 1.2: 1;

the preparation method of the epoxy resin-acrylic resin double-modified waterborne alkyd resin coating specifically comprises the following steps:

1) preheating an acrylic prepolymer to 80 ℃, adding E20 bisphenol A epoxy resin, a catalyst (0.01-1 wt% of tetraethylammonium bromide), a polymerization inhibitor (2, 6-di-tert-butyl-p-cresol/0.01-1 wt%) into the acrylic prepolymer, heating to 110 ℃, and stopping reaction when the acid value is lower than 6mgKOH/g through heat preservation reaction to obtain acrylic modified bisphenol A epoxy resin;

2) Adding polybasic acid, polyalcohol and trimellitic anhydride into a reaction kettle according to a given ratio, and stopping reaction at 230 ℃ until the acid value is 10mg KOH/g;

3) adding the product obtained in the step 1) into the step 2), adding a cosolvent, and reacting for 6 hours at the temperature of 80 ℃;

4) cooling to 50 ℃, adding a neutralizing agent, reacting for 40min under the condition of heat preservation, adding deionized water, adjusting the solid content to 95%, and discharging.

The polyalcohol is selected from a complex of pentaerythritol and sorbitol, and the equivalent ratio of hydroxyl content of the polyalcohol to the sorbitol is 1: 1;

the polybasic acid is selected from soybean oil fatty acid, the acid value is 198-204mgKOH/g, and the iodine value is 120-125 mgKOH/g;

example 4

The waterborne alkyd resin based on the epoxy resin-acrylic resin is prepared from the following components in parts by weight:

80 parts of polyol, 60 parts of polybasic acid, 12 parts of water-based monomer, 6 parts of bisphenol a epoxy resin, 50 parts of acrylic prepolymer, 15 parts of cosolvent and 4 parts of neutralizer;

the acrylic prepolymer is polymerized by dialdehyde compound and trimethyl s-triazine, and then further polymerized by methyl methacrylate and maleic anhydride.

The preparation method of the acrylic prepolymer comprises the following steps:

1) Dialdehyde compound and trimethyl s-triazine are mixed according to a ratio of 4: 1 equivalent weight, dissolved in xylene, reacted for 10h at 80 ℃ with lewis base, and filtered to remove lewis base;

2) adding methyl methacrylate and maleic anhydride into the filtrate system obtained in the step 1), introducing nitrogen for 25min, adding an initiator, reacting at 170 ℃ for 4h, and fractionating xylene in the reaction process to obtain an acrylic prepolymer;

the Lewis base is selected from potassium hydroxide and sodium hydroxide; the molar ratio of the Lewis base to the trimethyl s-triazine is 2: 3;

the initiator is BPO, and the dosage of the initiator accounts for 0.1-0.015 percent of the total mass of the system;

the dialdehyde compound has the general formula of OHC- (CH)₂)₄-CHO；

The molar ratio of the methyl methacrylate to the trimethyl s-triazine is 16: 1;

the molar ratio of the methyl methacrylate to the maleic anhydride is 1.1: 1;

the preparation method of the epoxy resin-acrylic resin double-modified waterborne alkyd resin coating specifically comprises the following steps:

1) preheating an acrylic prepolymer to 76 ℃, adding E20 bisphenol A epoxy resin, a catalyst (0.01-1 wt% of tetraethylammonium bromide), a polymerization inhibitor (2, 6-di-tert-butyl-p-cresol/0.01-1 wt%) into the acrylic prepolymer, heating to 10 ℃, and stopping reaction when the acid value is lower than 6mgKOH/g through heat preservation reaction to obtain acrylic modified bisphenol A epoxy resin;

2) Adding polybasic acid, polyalcohol and trimellitic anhydride into a reaction kettle according to a given ratio, and stopping reaction at 200 ℃ until the acid value is 6mg KOH/g;

3) adding the product obtained in the step 1) into the step 2), adding a cosolvent, and reacting for 5 hours at the temperature of 60 ℃;

4) cooling to 50 ℃, adding a neutralizing agent, reacting for 30-40min under the condition of heat preservation, adding deionized water, adjusting the solid content to 85%, and discharging.

The polyalcohol is selected from a complex of pentaerythritol and sorbitol, and the equivalent ratio of hydroxyl content of the polyalcohol to the sorbitol is 1: 1;

the polybasic acid is selected from soybean oil fatty acid, the acid value is 198-204mgKOH/g, and the iodine value is 120-125 mgKOH/g;

performance testing

Comparing the alkyd resin prepared in the examples 2-4 with the commercially available alkyd resin, preparing an alkyd resin water paint according to the formula in the table 1, and testing the adhesion, surface drying and actual drying of the alkyd resin water paint; and (5) water resistance of the initial paint. The test results are shown in Table 2.

TABLE 1 waterborne alkyd paint formulation

TABLE 2 waterborne alkyd paint Properties