CN-122011296-A - Epoxy group-containing polyester modified waterborne acrylic resin and preparation method thereof

Abstract

The invention relates to the field of resin synthesis, in particular to an epoxy group-containing polyester modified waterborne acrylic resin and a preparation method thereof. The method comprises the following steps of 1, synthesizing a modifier, 2, synthesizing maleic acid-based epoxy resin, and 3, synthesizing polyester modified water-based acrylic resin. The epoxy group, the triazole ring and the polyester chain segment are simultaneously introduced into the resin prepared by the invention, so that the finally prepared coating has excellent adhesive force and excellent salt spray resistance. The epoxy group can form firm chemical bonding with the surface of the metal substrate, the polyester chain segment provides excellent toughness and spreadability, and the triazole ring has remarkable corrosion inhibition effect on the metal substrate and can form a compact passivation layer with metal ions.

Inventors

• LU GUOQUAN
• LU BAOJUN
• LV MINCHANG
• LV PENG

Assignees

• 四会市中科明辉化工科技有限公司

Dates

Publication Date

20260512

Application Date

20260127

Claims (10)

1. 1. The preparation method of the polyester modified waterborne acrylic resin containing the epoxy group is characterized by comprising the following steps: Step 1, synthesizing a modifier: under the protection of nitrogen, weighing 4-hydroxybutyl vinyl ether, 3-amino-5-mercapto-1, 2, 4-triazole and a photoinitiator, adding the materials into a first solvent, and reacting for 2-3 hours under the irradiation of ultraviolet light to obtain a modifier; Step2, synthesizing maleic acid-based epoxy resin: Adding diallyl maleate into a second solvent under the condition of ice-water bath, stirring uniformly, gradually adding m-chloroperoxybenzoic acid, heating to room temperature, stirring for 5-8h, and obtaining maleic acid-based epoxy resin after the reaction is finished; step 3, synthesizing polyester modified water-based acrylic resin: Mixing maleic acid-based epoxy resin and a third solvent, adding a first monomer and unsaturated polyester, pre-reacting, adding a second monomer, a modifier and a free radical initiator, and heating and stirring to react to obtain the polyester modified waterborne acrylic resin containing epoxy groups.
2. 2. The method for preparing the epoxy group-containing polyester modified aqueous acrylic resin according to claim 1, wherein in the step 1, the ultraviolet light has a wavelength of 365nm and a power of 10-20mW/cm 2 .
3. 3. The preparation method of the epoxy group-containing polyester modified aqueous acrylic resin according to claim 1, wherein in the step 1, the photoinitiator is at least one of benzoin dimethyl ether, benzoin diethyl ether, benzoin methyl ether and benzoin ethyl ether, and the addition amount of the photoinitiator is 1-5% of the mass of the 4-hydroxybutyl vinyl ether.
4. 4. The method for producing an epoxy group-containing polyester-modified aqueous acrylic resin according to claim 1, wherein the ratio of 4-hydroxybutyl vinyl ether, 3-amino-5-mercapto-1, 2, 4-triazole and first solvent in step 1 is 1g (1.1 to 1.5) g to 100mL.
5. 5. The method for producing an epoxy group-containing polyester-modified aqueous acrylic resin according to claim 1, wherein in the step 2, the ratio of diallyl maleate, m-chloroperoxybenzoic acid and the second solvent is (1.9-2.3) g (2.8-4.6) g:50mL.
6. 6. The method for producing an epoxy group-containing polyester-modified aqueous acrylic resin according to claim 1, wherein in the step 3, the first monomer comprises at least one of acrylic acid, methacrylic acid, butyl acrylate, ethyl methacrylate, and methyl methacrylate, and the second monomer comprises at least one of styrene, cyclohexyl methacrylate, and isobornyl methacrylate.
7. 7. The method for preparing the epoxy group-containing polyester modified aqueous acrylic resin according to claim 1, wherein in the step 3, the free radical initiator is at least one of dibenzoyl peroxide, potassium persulfate and sodium persulfate, and the mass ratio of the free radical initiator to the maleic group-containing epoxy resin is (0.5-1) g (10-30) g.
8. 8. The method for producing an epoxy group-containing polyester-modified aqueous acrylic resin according to claim 1, wherein in the step 3, the ratio of the modifier, the maleic acid-based epoxy resin, the first monomer, the unsaturated polyester, the second monomer and the third solvent is (2-6) g (10-30) g (5-15) g (20-40) g:100mL.
9. 9. The preparation method of the epoxy group-containing polyester modified waterborne acrylic resin is characterized in that the reaction process in the step 3 comprises the steps of adding a first monomer and unsaturated polyester, stirring for 2-3h at 55-65 ℃, dropwise adding a mixture of a second monomer and an initiator, heating to 85-95 ℃, controlling the dropwise adding time to 2h, continuing to keep the temperature and stirring for 2-4h after the dropwise adding is finished, and then cooling to 50-60 ℃.
10. 10. An epoxy group-containing polyester-modified aqueous acrylic resin produced by using the production method according to claim 1.

Description

Epoxy group-containing polyester modified waterborne acrylic resin and preparation method thereof Technical Field The invention relates to the field of resin synthesis, in particular to an epoxy group-containing polyester modified waterborne acrylic resin and a preparation method thereof. Background The water-based acrylic resin has been widely used in the fields of paint, ink, adhesive, etc. because of its advantages of light color, good gloss and color retention, excellent weather resistance, environmental friendliness, etc. However, conventional aqueous acrylic resins also have some inherent disadvantages, firstly, the "hot tack cold brittle" after film formation, i.e. the lowest film formation temperature is contradictory to the glass transition temperature, the high glass transition temperature resins are hard and brittle, the flexibility and adhesion are poor, and the low glass transition temperature resins are too soft and the heat resistance and stain resistance are poor. Among them, the water resistance and chemical resistance are poor, which is caused by the fact that the molecular chain of the resin contains a large amount of hydrophilic groups and the linear structure thereof, which limits the application of the resin in fields of high-demand corrosion resistance, industrial coating and the like. To overcome the above drawbacks, researchers have generally used physical blending or chemical modification methods to optimize the properties of aqueous acrylic resins. Among them, polyester resins are used for modifying acrylic resins due to their characteristics of flexible molecular structural design, good flexibility, excellent adhesion to various substrates, and the like. By incorporating the polyester into the acrylic backbone, the flexibility and fullness of the acrylic can be effectively improved. However, simple polyester modification sacrifices the hardness and water resistance of the resin, and the polyester segment itself is easily hydrolyzed, possibly resulting in a decrease in the storage stability and durability of the resin. Furthermore, epoxy resins are known for their excellent adhesion, hardness, chemical resistance and corrosion resistance. Attempts have also been made in the prior art to modify acrylic resins with epoxy resins, for example to prepare epoxy-acrylic hybrid emulsions. However, such methods often suffer from poor compatibility, poor emulsion stability, or premature ring opening of the epoxy group during the preparation process, resulting in loss of properties. Meanwhile, the epoxy resin is directly introduced to cause the cross-linking density of a resin system to be too high, so that the flexibility of a paint film is poor. In summary, it is difficult to achieve an ideal balance between the key properties of hardness, flexibility, adhesion, chemical resistance, and storage stability of the aqueous acrylic resin of the prior art. Therefore, there is an urgent need in the art to develop a novel aqueous resin which combines the weatherability of acrylic resin, the flexibility and adhesion of polyester resin, and introduces the high performance characteristics of epoxy resin while ensuring good water dispersion stability and application performance of the resin system. Disclosure of Invention Aiming at the problems in the prior art, the invention aims to provide polyester modified water-based acrylic resin containing epoxy groups and a preparation method thereof. The aim of the invention is realized by adopting the following technical scheme: In a first aspect, the invention provides a method for preparing an epoxy group-containing polyester modified aqueous acrylic resin, comprising the following steps: Step 1, synthesizing a modifier: under the protection of nitrogen, weighing 4-hydroxybutyl vinyl ether, 3-amino-5-mercapto-1, 2, 4-triazole and a photoinitiator, adding the materials into a first solvent, and reacting for 2-3 hours under the irradiation of ultraviolet light to obtain a modifier; Step2, synthesizing maleic acid-based epoxy resin: Adding diallyl maleate into a second solvent under the condition of ice-water bath, stirring uniformly, gradually adding m-chloroperoxybenzoic acid, heating to room temperature, stirring for 5-8h, and obtaining maleic acid-based epoxy resin after the reaction is finished; step 3, synthesizing polyester modified water-based acrylic resin: Mixing maleic acid-based epoxy resin and a third solvent, adding a first monomer and unsaturated polyester, pre-reacting, adding a second monomer, a modifier and a free radical initiator, and heating and stirring to react to obtain the polyester modified waterborne acrylic resin containing epoxy groups. Preferably, in the step 1, the wavelength of the ultraviolet light is 365nm, and the power is 10-20mW/cm 2. Preferably, in the step 1, the photoinitiator is at least one of benzoin dimethyl ether, benzoin diethyl ether, benzoin methyl ether and benzoin ethyl ether. Preferably, in the step 1, the ph