Preparation method of environment-friendly wear-resistant water-based paint

Abstract

The present application relates to the paint technical field, and disclose a kind of preparation method of environment-friendly wear-resistant water-based paint, water-based epoxy resin is added in water in the present application, modified polyester fiber, defoaming agent, thickening agent, pigment filler, dispersant, shear dispersion is carried out by high-speed dispersion machine, and environment-friendly wear-resistant water-based paint is obtained.The present application utilizes styrene base sulfonic acid imine monomer to carry out ultraviolet irradiation grafting modification to polyester fiber, introduces a large number of hydrophilic sulfonate group and active imino group on the surface of fiber, which is conducive to improving the dispersibility of polyester fiber in water-based epoxy resin coating, and improves wear resistance and hardness.Active imino group on the surface of modified polyester fiber can occur curing reaction with epoxy resin, strengthens the interfacial bonding force between polyester fiber and epoxy resin, has good toughening effect, improves the tensile strength, elongation at break and impact strength of epoxy resin.

Description

Technical Field

[0001] This invention relates to the field of coating technology, specifically to a method for preparing an environmentally friendly, wear-resistant water-based coating. Background Technology

[0002] Currently, most coatings are solvent-based, containing significant amounts of volatile solvents such as toluene, ethyl acetate, and acetone. These solvents readily evaporate during curing, causing considerable pollution. Therefore, developing water-based environmentally friendly coatings is of great importance. Water-based epoxy resin coatings, using water as a solvent, are environmentally friendly, possess excellent film-forming properties, high strength, and superior corrosion resistance. However, epoxy resins have relatively poor toughness and abrasion resistance, limiting their practical applications.

[0003] Using high-performance polymer fiber materials to fill and modify epoxy resin is an effective method to improve its mechanical properties. Polyester fibers have high strength, high modulus, good wear resistance, and excellent high-temperature resistance, and are widely used in coatings, plastics, rubber, and other materials. However, improving the compatibility between polyester fibers and the resin matrix remains a research challenge. Summary of the Invention

[0004] This invention solves the problem of poor mechanical properties such as wear resistance in epoxy resin coatings.

[0005] The technical solution provided by this invention is: a method for preparing an environmentally friendly, wear-resistant water-based coating, comprising the following steps:

[0006] Step (1): Place the cleaned and dried polyester fiber in ethanol, stir, add benzophenone and styrene sulfonate imine monomer, place under ultraviolet light, carry out grafting reaction in nitrogen atmosphere, filter, wash with xylene, ethanol and water in sequence, and dry to obtain modified polyester fiber.

[0007] The styrene sulfonate imine monomer has the following structural formula (Ⅰ):

[0008]

[0009] Step (2): Add waterborne epoxy resin, modified polyester fiber, defoamer, thickener, pigments and fillers and dispersant to water, and then disperse to obtain environmentally friendly wear-resistant waterborne coating.

[0010] Furthermore, in step (1), the power of the ultraviolet lamp is 100-300W and the wavelength is 360nm.

[0011] Furthermore, in step (1), the mass of benzophenone and styrene sulfonate imine monomer is 1.2-2.6% and 20-40% of the mass of polyester fiber, respectively.

[0012] Furthermore, the temperature during the grafting reaction in step (1) is 25-35℃ and the time is 20-40min.

[0013] Furthermore, in step (2), the mass of the modified polyester fiber is 1-6% of the mass of the waterborne epoxy resin.

[0014] Further, the preparation method of styrenesulfonate imine monomer includes: adding taurine and potassium hydroxide to methanol, stirring, then adding 4-vinylbenzaldehyde, heating to 50-60℃, carrying out a Schiff base reaction for 3-4 hours, filtering, adding the precipitate to methanol, then adding potassium borohydride and water, carrying out a reduction reaction at 20-30℃ for 2-3 hours, vacuum distillation, and recrystallizing the product in a 60% (v / v) aqueous ethanol solution to obtain the styrenesulfonate imine monomer. The reaction formula is:

[0015]

[0016] Furthermore, the molar ratio of taurine, potassium hydroxide, 4-vinylbenzaldehyde, and potassium borohydride is 1:1:(0.9-1.1):(1.2-1.4).

[0017] The technical effect of this invention is as follows: By using styrene-sulfonate imine monomer to perform ultraviolet irradiation graft modification on polyester fibers, a large number of hydrophilic sulfonate groups and active imine groups are introduced on the fiber surface, which significantly improves the surface hydrophilicity of polyester fibers. This is beneficial to improving the dispersibility of polyester fibers in water-based epoxy resin coatings. The better the dispersibility, the better the modification effect of polyester fibers, which is beneficial to reducing the frictional mass loss of epoxy resin coatings, improving wear resistance, and increasing the hardness of the coating film.

[0018] The active imino groups on the surface of the modified polyester fiber of this invention can undergo a curing reaction with epoxy resin, thereby bonding the polyester fiber with the epoxy resin through chemical bonding. This enhances the interfacial bonding force between the polyester fiber and the epoxy resin. When the epoxy resin is subjected to external force, many microcracks are generated inside. The polyester fiber bonded in the resin matrix can absorb and transfer stress, preventing the rapid propagation of cracks and exhibiting a good toughening effect. This improves the tensile strength, elongation at break, and impact strength of the epoxy resin. Detailed Implementation

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Example 1

[0021] (1) Add 30 mmol taurine and 30 mmol potassium hydroxide to 80 mL methanol, stir, add 30 mmol 4-vinylbenzaldehyde, heat to 50 °C, carry out Schiff base reaction for 4 h, filter, add the precipitate to 70 mL methanol, then add 42 mmol potassium borohydride and 50 mL water, carry out reduction reaction at 25 °C for 2 h, distill under reduced pressure, recrystallize the product in 60% ethanol aqueous solution to obtain styrene sulfonate imine monomer.

[0022] (2) Place 10g of cleaned and dried polyester fiber in 80mL of ethanol, stir, add 0.17g of benzophenone and 2.7g of styrene sulfonate imine monomer, place under a 200W ultraviolet lamp with a wavelength of 360nm, and carry out the grafting reaction at 30℃ for 20min in a nitrogen atmosphere. After filtration, wash with xylene, ethanol and water in sequence, and dry to obtain modified polyester fiber.

[0023] (3) Add 500g of waterborne epoxy resin AR555, 5g of modified polyester fiber, 1.8g of defoamer FoamStar ED 2522, 1.3g of thickener TF-938, 110g of pigment and filler titanium dioxide, and 8.6g of dispersant BYK-110 to 600mL of water. Shear dispersion is carried out by high-speed disperser to obtain environmentally friendly and wear-resistant waterborne coating.

[0024] Example 2

[0025] (1) Add 30 mmol taurine and 30 mmol potassium hydroxide to 100 mL methanol, stir, add 33 mmol 4-vinylbenzaldehyde, heat to 50 °C, carry out Schiff base reaction for 4 h, filter, add the precipitate to 80 mL methanol, then add 40 mmol potassium borohydride and 50 mL water, carry out reduction reaction at 20 °C for 3 h, distill under reduced pressure, recrystallize the product in 60% ethanol aqueous solution to obtain styrene sulfonate imine monomer.

[0026] (2) Place 10g of cleaned and dried polyester fiber in 80mL of ethanol, stir, add 0.12g of benzophenone and 2g of styrene sulfonate imine monomer, place under a 100W ultraviolet lamp with a wavelength of 360nm, and carry out the grafting reaction at 25℃ for 40min in a nitrogen atmosphere. After filtration, wash with xylene, ethanol and water in sequence, and dry to obtain modified polyester fiber.

[0027] (3) Add 500g of waterborne epoxy resin AR555, 10g of modified polyester fiber, 1.8g of defoamer FoamStar ED 2522, 1.3g of thickener TF-938, 110g of pigment and filler titanium dioxide, and 8.6g of dispersant BYK-110 to 600mL of water and shear disperse them using a high-speed disperser to obtain an environmentally friendly and wear-resistant waterborne coating.

[0028] Example 3

[0029] (1) Add 30 mmol taurine and 30 mmol potassium hydroxide to 80 mL methanol, stir, add 27 mmol 4-vinylbenzaldehyde, heat to 60 °C, carry out Schiff base reaction for 3 h, filter, add the precipitate to 70 mL methanol, then add 40 mmol potassium borohydride and 40 mL water, carry out reduction reaction at 30 °C for 3 h, distill under reduced pressure, recrystallize the product in 60% ethanol aqueous solution to obtain styrene sulfonate imine monomer.

[0030] (2) Place 10g of cleaned and dried polyester fiber in 80mL of ethanol, stir, add 0.26g of benzophenone and 4g of styrene sulfonate imine monomer, place under a 300W ultraviolet lamp with a wavelength of 360nm, and carry out the grafting reaction at 35℃ for 20min in a nitrogen atmosphere. After filtration, wash with xylene, ethanol and water in sequence, and dry to obtain modified polyester fiber.

[0031] (3) Add 500g of waterborne epoxy resin AR555, 20g of modified polyester fiber, 1.8g of defoamer FoamStar ED 2522, 1.3g of thickener TF-938, 110g of pigment and filler titanium dioxide, and 8.6g of dispersant BYK-110 to 600mL of water. Shear dispersion is carried out by high-speed disperser to obtain environmentally friendly and wear-resistant waterborne coating.

[0032] Example 4

[0033] (1) Add 30 mmol taurine and 30 mmol potassium hydroxide to 100 mL methanol, stir, add 30 mmol 4-vinylbenzaldehyde, heat to 55 °C, carry out Schiff base reaction for 4 h, filter, add the precipitate to 60 mL methanol, then add 36 mmol potassium borohydride and 40 mL water, carry out reduction reaction at 20 °C for 3 h, distill under reduced pressure, recrystallize the product in 60% ethanol aqueous solution to obtain styrene sulfonate imine monomer.

[0034] (2) Place 10g of cleaned and dried polyester fiber in 80mL of ethanol, stir, add 0.21g of benzophenone and 3.4g of styrene sulfonate imine monomer, place under a 200W UV lamp with a wavelength of 360nm, and carry out the grafting reaction at 30℃ for 30min in a nitrogen atmosphere. After filtration, wash with xylene, ethanol and water in sequence, and dry to obtain modified polyester fiber.

[0035] (3) Add 500g of waterborne epoxy resin AR555, 30g of modified polyester fiber, 1.8g of defoamer FoamStar ED 2522, 1.3g of thickener TF-938, 110g of pigment and filler titanium dioxide, and 8.6g of dispersant BYK-110 to 600mL of water, and shear disperse them using a high-speed disperser to obtain an environmentally friendly and wear-resistant waterborne coating.

[0036] Comparative Example 1

[0037] (1) Add 500g of waterborne epoxy resin AR555, 1.8g of defoamer FoamStar ED 2522, 1.3g of thickener TF-938, 110g of pigment and filler titanium dioxide, and 8.6g of dispersant BYK-110 to 600mL of water and shear disperse them using a high-speed disperser to obtain an environmentally friendly and wear-resistant waterborne coating.

[0038] Comparative Example 2

[0039] (1) Add 500g of waterborne epoxy resin AR555, 5g of polyester fiber, 1.8g of defoamer FoamStarED 2522, 1.3g of thickener TF-938, 110g of pigment and filler titanium dioxide, and 8.6g of dispersant BYK-110 to 600mL of water and shear disperse them using a high-speed disperser to obtain an environmentally friendly and wear-resistant waterborne coating.

[0040] Comparative Example 3

[0041] (1) Place 10g of cleaned and dried polyester fiber in 80mL of ethanol, stir, add 0.17g of benzophenone and 2.7g of sodium 4-styrenesulfonate, place under a 200W UV lamp with a wavelength of 360nm, and carry out the grafting reaction at 30℃ for 20min in a nitrogen atmosphere. After filtration, wash with xylene, ethanol and water in sequence, and dry to obtain modified polyester fiber.

[0042] (2) Add 500g of waterborne epoxy resin AR555, 5g of modified polyester fiber, 1.8g of defoamer FoamStar ED 2522, 1.3g of thickener TF-938, 110g of pigment and filler titanium dioxide, and 8.6g of dispersant BYK-110 to 600mL of water. Shear dispersion is carried out by high-speed disperser to obtain environmentally friendly and wear-resistant waterborne coating.

[0043] 130g of polyetheramine D230 curing agent was added to the environmentally friendly wear-resistant water-based coatings prepared in each embodiment and comparative example. After mixing, the coatings were first cured at 70°C for 4 hours, and then cured at 130°C for 2 hours to form a paint film.

[0044] The frictional mass loss and abrasion resistance of the paint film were tested according to GB / T 1768-2006 standard. The load was 1 kg, the rotation speed was 60 r / min, and the number of abrasion cycles was 10,000. The hardness of the paint film was tested according to GB / T 6739-2022 standard. The test results are shown in Table 1.

[0045] Table 1 Performance Tests of Coating Films

[0046]

[0047] The coating with added curing agent was poured into a mold and cured first at 70℃ for 4 hours, then at 130℃ for 4 hours to form a casting. The tensile properties and impact strength were tested according to GB / T 2567-2021 standard. The test results are shown in Table 2.

[0048] Table 2 Performance Tests of Castables

[0049]

[0050] As shown in Table 1, the epoxy resin coating of Comparative Example 1, which did not contain polyester fiber, had a relatively high frictional mass loss of 57.1 mg, indicating poor wear resistance, and its pencil hardness was only 2H. Furthermore, the tensile strength, elongation at break, and impact strength of the coating casting were low, resulting in poor mechanical properties.

[0051] The modified polyester fibers added to the epoxy resin coatings in Examples 1-4 are modified by UV irradiation grafting of styrene-sulfonate imine monomers. This introduces a large number of hydrophilic sulfonate groups and active imino groups on the surface of the polyester fibers, significantly improving their surface hydrophilicity. This is beneficial for improving the dispersibility of the polyester fibers in waterborne epoxy resin coatings. The better the dispersibility, the better the modification effect of the polyester fibers. Furthermore, the active imino groups on the surface of the modified polyester fibers can undergo a curing reaction with the epoxy resin, thereby chemically bonding the polyester fibers to the epoxy resin and enhancing the interfacial bonding force between the polyester fibers and the epoxy resin. When the epoxy resin is subjected to external force, many microcracks are generated inside. The polyester fibers bonded in the resin matrix can absorb and transfer stress, preventing the rapid propagation of cracks and exhibiting a good toughening effect. This improves the tensile strength, elongation at break, and impact strength of the epoxy resin.

[0052] Comparative Example 2, which incorporates unmodified polyester fibers, exhibits poor hydrophilicity and dispersion in waterborne epoxy resins. Furthermore, its surface lacks active imino groups, preventing it from undergoing a curing reaction with the epoxy resin. Consequently, it results in poor toughening, significant frictional mass loss in the epoxy resin coating, poor wear resistance, and low pencil hardness. Additionally, the epoxy resin casting exhibits low tensile strength, elongation at break, and impact strength.

[0053] Comparative Example 3 uses sodium 4-styrene sulfonate to irradiate and graft polyester fibers, introducing hydrophilic sulfonate groups on the surface of the polyester fibers, which improves the dispersibility of the polyester fibers in waterborne epoxy resin. The frictional mass loss of the epoxy resin film is lower than that of Comparative Example 1 and Comparative Example 2, and the hardness, tensile strength, elongation at break and impact strength are higher. However, it does not contain active imino groups and cannot undergo a curing reaction with epoxy resin. The toughening effect is weaker than that of the other examples, resulting in lower mechanical properties than those of the other examples.

[0054] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing an environmentally friendly, wear-resistant water-based coating, characterized in that, The preparation method includes the following steps: Step (1): Place the cleaned and dried polyester fiber in ethanol, stir, add benzophenone and monomer, place under ultraviolet light, carry out grafting reaction in nitrogen atmosphere, filter, wash with xylene, ethanol and water in sequence, dry, and obtain modified polyester fiber. The monomer has the following structural formula (Ⅰ): Equation (I); Step (2): Add waterborne epoxy resin, modified polyester fiber, defoamer, thickener, pigments and fillers and dispersant to water, and then disperse to obtain environmentally friendly wear-resistant waterborne coating; In step (1), the mass of benzophenone and monomer is 1.2-2.6% and 20-40% of the mass of polyester fiber, respectively.

2. The method for preparing the environmentally friendly wear-resistant water-based coating according to claim 1, characterized in that, The ultraviolet lamp in step (1) has a power of 100-300W and a wavelength of 360nm.

3. The method for preparing the environmentally friendly wear-resistant water-based coating according to claim 1, characterized in that, The temperature of the grafting reaction in step (1) is 25-35℃ and the time is 20-40min.

4. The method for preparing the environmentally friendly wear-resistant water-based coating according to claim 1, characterized in that, In step (2), the mass of the modified polyester fiber is 1-6% of the mass of the waterborne epoxy resin.

5. The method for preparing the environmentally friendly wear-resistant water-based coating according to claim 1, characterized in that, The method for preparing the monomer includes: adding taurine and potassium hydroxide to methanol, stirring, adding 4-vinylbenzaldehyde, performing a Schiff base reaction, filtering, adding the precipitate to methanol, then adding potassium borohydride and water, performing a reduction reaction, distilling under reduced pressure, and recrystallizing the product in an ethanol-water solution to obtain the monomer; the molar ratio of taurine, potassium hydroxide, 4-vinylbenzaldehyde, and potassium borohydride is 1:1:(0.9-1.1):(1.2-1.4).

6. The method for preparing the environmentally friendly wear-resistant water-based coating according to claim 5, characterized in that, The Schiff base reaction is carried out at a temperature of 50-60℃ for 3-4 hours; the reduction reaction is carried out at a temperature of 20-30℃ for 2-3 hours.

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