Water-based plastic stoving varnish with high aging resistance and preparation method of water-based plastic stoving varnish

Abstract

The invention discloses water-based plastic stoving varnish with high aging resistance and a preparation method thereof, and relates to the technical field of water-based paint. The invention discloses a preparation method of water-based plastic stoving varnish, which comprises the following steps: adding water-based resin, N, N-dimethylethanolamine and deionized water into a dispersion cylinder, and uniformly dispersing; continuing to add isopropanol and a coalescing agent, and uniformly dispersing; sequentially adding a wetting agent, a defoaming agent and a thickening agent, uniformly dispersing, and filtering to obtain the water-based plastic stoving varnish. The water-based resin prepared in the invention is obtained by copolymerization of silicon dioxide modified epoxy resin and acrylic resin, and the water-based plastic stoving varnish prepared in the invention has excellent aging resistance and good mechanical properties.

Description

Technical Field

[0001] The invention relates to the technical field of water-based coatings, and in particular to a water-based plastic baking varnish with high anti-aging performance and a preparation method thereof. Background Art

[0002] With the development of society and the improvement of economic level, people's desire for high-quality life has become stronger. A large part of the metal or plastic parts used in daily life are painted with paint to achieve aesthetic and protective needs. Traditional paint generally uses oil-based polyester or oil-based acrylic / amino paint, which will cause a series of environmental pollution during the painting process and pose a health threat to the painting operator. With the improvement of people's environmental awareness and the restrictions on volatile organic compounds (VOCs) emissions by relevant national departments, the promotion of the use of water-based paint has become a general trend.

[0003] Resins that can be used as base materials for water-based paints include alkyd, epoxy, acrylic, polyurethane and polyester resins. Epoxy resins are widely used in the coatings industry due to their strong adhesion and resistance to chemical corrosion. However, epoxy resins have poor compatibility with water, resulting in poor hardness, wear resistance and aging resistance of water-based plastic paints prepared with epoxy resins as base materials. Water-soluble acrylic resins have poor adhesion and corrosion resistance. Although the adhesion and chemical resistance of epoxy-modified water-soluble acrylic resins have been improved, there are still problems with low gloss and poor aging resistance, which affect the appearance and fullness of the coating. Summary of the invention

[0004] The purpose of the present invention is to provide a water-based plastic baking varnish with high anti-aging performance and a preparation method thereof, so as to solve the following technical problems:

[0005] The existing paint prepared from the resin base obtained by cross-linking and modifying epoxy resin and acrylate resin has the problems of high viscosity, low gloss and poor aging resistance, which affects the coating appearance and fullness.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A method for preparing a water-based plastic baking varnish with high anti-aging performance comprises the following steps:

[0008] Add water-based resin, N, N-dimethylethanolamine and deionized water into a dispersion tank and disperse them evenly; continue to add isopropyl alcohol and film-forming aid and disperse them evenly; add wetting agent, defoaming agent and thickener in sequence, disperse them evenly, filter and obtain water-based plastic baking paint.

[0009] As a further embodiment of the present invention, the mass ratio of water-based resin, N,N-dimethylethanolamine, deionized water, isopropanol, film-forming aid, wetting agent, defoaming agent and thickener is 60-70: 0.4-0.8: 25-35: 1-2: 1-2: 0.7-1.5: 0.5-1: 0.5-1.

[0010] As a further solution of the present invention: the wetting agent is a mixture of SN-3704 and BYK-346 in a mass ratio of 1:1; the defoaming agent is TEGO-902w; the film-forming aid is ethylene glycol butyl ether; and the thickener is BASF-3800.

[0011] As a further embodiment of the present invention: the preparation method of the water-based resin comprises the following steps:

[0012] S1: Add cyclohexane, n-hexanol and Triton X-100 to reaction bottle A, disperse evenly, add deionized water, disperse evenly, add ammonia water, tetraethyl orthosilicate and 3-(trihydroxysilyl)propylmethyl phosphate, stir for 18-24h, add anhydrous ethanol to break the emulsion, centrifuge and filter to obtain component 1;

[0013] S2: Add epoxy resin, ethylene glycol butyl ether and n-butanol into reaction bottle B, control the temperature at 90-100°C, add component 1, keep warm and reflux for 1-3 hours to obtain component 2;

[0014] S3: Add component 2, acrylic acid, butyl acrylate and methyl methacrylate into reaction bottle C, control the temperature at 110-120°C, add benzoyl peroxide, keep the reaction warm for 1-3h, control the temperature at 50-60°C, add distilled water to dilute to 30-40% solid content, adjust the pH to 8-9, and obtain water-based resin.

[0015] As a further scheme of the present invention: the ammonia water in S1 is 10-20wt% ammonia water, and the addition ratio of cyclohexane, n-hexanol, Triton X-100, deionized water, ammonia water, tetraethyl orthosilicate, 3-(trihydroxysilyl)propylmethyl phosphate, and anhydrous ethanol in S1 is 15mL: 3-5mL: 3-4.5g: 1-2mL: 0.2-0.3mL: 0.3-0.6mL: 0.1-0.15mL: 20-30mL.

[0016] As a further solution of the present invention: the mass ratio of epoxy resin, ethylene glycol butyl ether, n-butanol and component one in S2 is 20:5-10:2.5-5:1-2.

[0017] As a further solution of the present invention: the mass ratio of component 2, acrylic acid, butyl acrylate, methyl methacrylate and benzoyl peroxide in S3 is 100:10-15:2-3:3-5:0.5-1.

[0018] A water-based plastic baking varnish with high anti-aging performance is prepared by any one of the above preparation methods.

[0019] Beneficial effects of the present invention:

[0020] The present application firstly uses tetraethyl orthosilicate as a raw material to prepare silicon dioxide, and adds 3-(trihydroxysilyl)propylmethyl phosphate during the preparation process to graft a large number of phosphoric acid groups on the surface of silicon dioxide to obtain component one; then the phosphoric acid groups on component one are used for reaction and grafting with epoxy resin to obtain component two, so that silicon dioxide is organically grafted on the epoxy resin molecular chain; then component two is copolymerized with acrylic acid and acrylate monomers, and the epoxy ring undergoes an esterification ring-opening reaction with the added acrylic acid monomer, and an unsaturated double bond is introduced at the chain end of the resin. Free radicals initiate polymerization at the epoxy chain end to form an epoxy acrylic resin rich in acid groups, so that the prepared water-based resin has the advantages of both epoxy resin and acrylic resin, and not only has good adhesion, but also good light and heat resistance. The baking paint prepared in the present application has excellent corrosion resistance and chemical resistance, and has excellent adhesion and good flexibility to a variety of substrates, and the grafting of component one and copolymerized acrylic resin on the epoxy resin molecular chain gives the paint the advantages of high gloss and good light and color retention. DETAILED DESCRIPTION

[0021] The following will be described clearly and completely in conjunction with the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] Example 1

[0023] The preparation method of water-based resin comprises the following steps:

[0024] S1: Add 750 mL of cyclohexane, 150 mL of n-hexanol, and 150 g of Triton X-100 to reaction bottle A, disperse evenly, add 50 mL of deionized water, disperse evenly, add 10 mL of 20 wt% ammonia water, 15 mL of tetraethyl orthosilicate, and 5 mL of 3-(trihydroxysilyl)propylmethyl phosphate, stir for 18 h, add 1000 mL of anhydrous ethanol to demulsify, centrifuge, and filter to obtain component 1;

[0025] S2: Add 100g epoxy resin (E20), 25g ethylene glycol butyl ether, and 12.5g n-butanol into reaction bottle B, control the temperature at 90-100°C, add 5g component 1, keep warm and reflux for 1-3h to obtain component 2;

[0026] S3: Add 100g of component 2, 10g of acrylic acid, 2g of butyl acrylate and 3g of methyl methacrylate into reaction bottle C, control the temperature at 110°C, add 0.5g of benzoyl peroxide, keep the reaction warm for 1h, control the temperature at 50°C, add distilled water to dilute to 30% solid content, adjust the pH to 8, and obtain a water-based resin.

[0027] Example 2

[0028] The preparation method of water-based resin comprises the following steps:

[0029] S1: Add 750 mL of cyclohexane, 200 mL of n-hexanol, and 200 g of Triton X-100 to reaction bottle A, disperse evenly, add 70 mL of deionized water, disperse evenly, add 12 mL of 20 wt% ammonia water, 20 mL of tetraethyl orthosilicate, and 6 mL of 3-(trihydroxysilyl)propylmethyl phosphate, stir for 21 h, add 1200 mL of anhydrous ethanol to demulsify, centrifuge, and filter to obtain component 1;

[0030] S2: Add 100g epoxy resin (E20), 35g ethylene glycol butyl ether and 17g n-butanol into reaction bottle B, control the temperature at 100°C, add 7g component 1, keep warm and reflux for 3h to obtain component 2;

[0031] S3: Add 100g of component 2, 12g of acrylic acid, 2.5g of butyl acrylate and 4g of methyl methacrylate into reaction bottle C, control the temperature at 115°C, add 1g of benzoyl peroxide, keep the reaction warm for 3h, control the temperature at 55°C, add distilled water to dilute to 30% solid content, adjust the pH to 8, and obtain a water-based resin.

[0032] Example 3

[0033] The preparation method of water-based resin comprises the following steps:

[0034] S1: Add 750 mL of cyclohexane, 250 mL of n-hexanol, and 225 g of Triton X-100 to reaction bottle A, disperse evenly, add 100 mL of deionized water, disperse evenly, add 15 mL of 20 wt% ammonia water, 30 mL of tetraethyl orthosilicate, and 7.5 mL of 3-(trihydroxysilyl)propylmethyl phosphate, stir for 24 h, add 1500 mL of anhydrous ethanol to demulsify, centrifuge, and filter to obtain component 1;

[0035] S2: Add 100g of epoxy resin (E20), 50g of ethylene glycol butyl ether and 25g of n-butanol into reaction bottle B, control the temperature at 100°C, add 10g of component 1, keep the temperature under reflux for 3h, and obtain component 2;

[0036] S3: Add 100g of component 2, 15g of acrylic acid, 3g of butyl acrylate and 5g of methyl methacrylate into reaction bottle C, control the temperature at 120°C, add 1g of benzoyl peroxide, keep warm for 3h, control the temperature at 60°C, add distilled water to dilute to 30% solid content, adjust pH 8, and obtain water-based resin.

[0037] Example 4

[0038] A method for preparing a water-based plastic baking varnish with high anti-aging performance comprises the following steps:

[0039] 70 g of the water-based resin prepared in Example 1, 0.8 g of N,N-dimethylethanolamine, and 30 g of deionized water were added to a dispersion tank and dispersed evenly; 1 g of isopropanol and 2 g of ethylene glycol butyl ether were added and dispersed evenly; 0.5 g of SN-3704, 0.5 g of BYK-346, 0.5 g of TEGO-902w, and 0.7 g of BASF-3800 were added in sequence, dispersed evenly, and filtered to obtain a water-based plastic baking paint.

[0040] Example 5

[0041] A method for preparing a water-based plastic baking varnish with high anti-aging performance comprises the following steps:

[0042] 70g of the water-based resin prepared in Example 2, 0.8g of N,N-dimethylethanolamine, and 30g of deionized water were added to a dispersion tank and dispersed evenly; 1g of isopropanol and 2g of ethylene glycol butyl ether were added and dispersed evenly; 0.5g of SN-3704, 0.5g of BYK-346, 0.5g of TEGO-902w, and 0.7g of BASF-3800 were added in sequence, dispersed evenly, and filtered to obtain a water-based plastic baking paint.

[0043] Example 6

[0044] A method for preparing a water-based plastic baking varnish with high anti-aging performance comprises the following steps:

[0045] 70g of the water-based resin prepared in Example 3, 0.8g of N,N-dimethylethanolamine, and 30g of deionized water were added to a dispersion tank and dispersed evenly; 1g of isopropanol and 2g of ethylene glycol butyl ether were added and dispersed evenly; 0.5g of SN-3704, 0.5g of BYK-346, 0.5g of TEGO-902w, and 0.7g of BASF-3800 were added in sequence, dispersed evenly, and filtered to obtain a water-based plastic baking paint.

[0046] Comparative Example 1

[0047] The preparation method of water-based resin comprises the following steps:

[0048] S1: Add 750 mL of cyclohexane, 150 mL of n-hexanol, and 150 g of Triton X-100 to reaction bottle A, disperse evenly, add 50 mL of deionized water, disperse evenly, add 10 mL of 20 wt% ammonia water, 15 mL of tetraethyl orthosilicate, stir for 18 h, add 1000 mL of anhydrous ethanol to demulsify, centrifuge, and filter to obtain component 1;

[0049] S2: Add 100g epoxy resin (E20), 25g ethylene glycol butyl ether, and 12.5g n-butanol into reaction bottle B, control the temperature at 90-100°C, add 5g component 1, keep warm and reflux for 1-3h to obtain component 2;

[0050] S3: Add 100g of component 2, 10g of acrylic acid, 2g of butyl acrylate and 3g of methyl methacrylate into reaction bottle C, control the temperature at 110°C, add 0.5g of benzoyl peroxide, keep the reaction warm for 1h, control the temperature at 50°C, add distilled water to dilute to 30% solid content, adjust the pH to 8, and obtain a water-based resin.

[0051] Comparative Example 2

[0052] The preparation method of water-based resin comprises the following steps:

[0053] Add 100g epoxy resin (E20), 10g acrylic acid, 2g butyl acrylate and 3g methyl methacrylate into reaction bottle C, control the temperature at 110°C, add 0.5g benzoyl peroxide, keep the reaction for 1h, control the temperature at 50°C, add distilled water to dilute to 30% solid content, adjust the pH to 8, and obtain a water-based resin.

[0054] Comparative Example 3

[0055] The preparation method of water-based resin comprises the following steps:

[0056] S1: Add 750 mL of cyclohexane, 150 mL of n-hexanol, and 150 g of Triton X-100 to reaction bottle A, disperse evenly, add 50 mL of deionized water, disperse evenly, add 10 mL of 20 wt% ammonia water, 15 mL of tetraethyl orthosilicate, and 5 mL of 3-(2,3-epoxypropoxy)propyltrimethoxysilane, stir for 18 h, add 1000 mL of anhydrous ethanol to demulsify, centrifuge, and filter to obtain component 1;

[0057] S2: Add 100g epoxy resin (E20), 25g ethylene glycol butyl ether, and 12.5g n-butanol into reaction bottle B, control the temperature at 90-100°C, add 5g component 1, keep warm and reflux for 1-3h to obtain component 2;

[0058] S3: Add 100g of component 2, 10g of acrylic acid, 2g of butyl acrylate and 3g of methyl methacrylate into reaction bottle C, control the temperature at 110°C, add 0.5g of benzoyl peroxide, keep the reaction warm for 1h, control the temperature at 50°C, add distilled water to dilute to 30% solid content, adjust the pH to 8, and obtain a water-based resin.

[0059] Comparative Example 4

[0060] Compared with Example 4, Comparative Example 4 only replaces the aqueous resin prepared in Example 1 added in Example 4 with an equal amount of the aqueous resin prepared in Comparative Example 1, and the remaining components and preparation method are completely consistent with Example 4.

[0061] Comparative Example 5

[0062] Compared with Example 4, in Comparative Example 5, only an equal amount of the aqueous resin prepared in Example 1 added in Example 4 is replaced by an aqueous resin prepared in Comparative Example 2, and the remaining components and preparation method are completely consistent with those of Example 4.

[0063] Comparative Example 6

[0064] Compared with Example 4, Comparative Example 6 only replaces the aqueous resin prepared in Example 1 added in Example 4 with an equal amount of the aqueous resin prepared in Comparative Example 3, and the remaining components and preparation method are completely consistent with Example 4.

[0065] Performance testing:

[0066] Plate making method: Wipe the galvanized plate clean with isopropyl alcohol, spray the baking varnish prepared in Example 4-6 and Comparative Example 4-6, flash dry for 5 minutes, and then gradually heat up to 180°C for curing for 30 minutes;

[0067] (1) Adhesion: The test was carried out according to the test method of GB / T 9286-1998 “Scratch test for paint and varnish films”; the test results are shown in Table 1;

[0068] (2) Pencil hardness: According to GB / T 6739-2006 “Paints and varnishes: Determination of film hardness by pencil method”; the test results are shown in Table 1;

[0069] Table 1: Statistical table of mechanical properties test data of Examples 4-6 and Comparative Examples 4-6

[0070] Film thickness hardness Adhesion(grade) Example 4 25±5um 3H 0 Example 5 25±5um 3H 0 Example 6 25±5um 3H 0 Comparative Example 4 25±5um 3H 2 Comparative Example 5 25±5um 1H 3 Comparative Example 6 25±5um 3H 1

[0071] It can be seen from Table 1 that the baking varnish prepared by adding the water-based resin prepared in the present application into the paint has excellent mechanical properties.

[0072] (3) Rubber test: carried out according to GB / T 1768-79 coating abrasion resistance determination method; the test results are shown in Table 2;

[0073] (4) RAC tape test: performed according to ASTM F2357 coating film resistance to RCA tape test standard; the test results are shown in Table 2;

[0074] (5) Isopropyl alcohol resistance: tested according to ASTM D5402-06 (2011) “Determination of solvent rub resistance of organic coatings by solvent rub method”; the test results are shown in Table 2;

[0075] Table 2: Statistical table of performance test data of Examples 4-6 and Comparative Examples 4-6

[0076]

[0077]

[0078] It can be seen from Table 2 that the baking varnish prepared in the present application has good solvent resistance and friction resistance.

[0079] (6) Gloss: According to GB / T 9754-2007, the gloss meter BGD516 / 3 was used for testing. The test results are shown in Table 1.

[0080] (7) Aging resistance: According to ASTM G154-06 (QUA / SPRAY, Q-Lab, USA), the total aging time is 1200 hours, each aging cycle is 12 hours, and the first 8 hours of ultraviolet radiation, wavelength 340nm, irradiation intensity 0.89W˙m -2 , the internal temperature of the aging box is 60℃, the last 4h is the cooling process, the internal temperature is 50℃; and the paint film gloss loss rate η and color difference value ΔE are calculated according to the following formula; the test results are shown in Table 3;

[0081] Light loss rate η = [(A0-A1) / A0] × 100%

[0082] Wherein, η-gloss loss rate, %; A0-gloss measurement value before aging; A1-gloss measurement value before aging; color difference value ΔE=[(ΔL) 2 +(Δa) 2 +(Δb) 2 ] 1 / 2

[0083] Where, L-lightness; a-red-green color index; b-yellow-blue color index;

[0084] Table 3: Statistical table of aging resistance test data of Examples 4-6 and Comparative Examples 4-6

[0085] Glossiness (60℃) Light loss rate η(%) Color difference ΔE Example 4 107.1 7.2 12.1 Example 5 107.7 6.6 11.5 Example 6 106.7 7.7 12.5 Comparative Example 4 93.2 61.5 16.4 Comparative Example 5 98.1 73.4 20.1 Comparative Example 6 102.1 50.2 14.5

[0086] It can be seen from Table 3 that the baking varnish prepared in the present application has high gloss, and even after aging treatment, the gloss loss rate and color difference value are still very small, that is, the baking varnish prepared in the present application also has excellent aging resistance.

[0087] The above is a detailed description of an embodiment of the present invention, but the content is only a preferred embodiment of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A method for preparing a water-based plastic baking varnish with high anti-aging performance, characterized in that: The steps include: Add water-based resin, N, N-dimethylethanolamine and deionized water into a dispersion tank and disperse them evenly; continue to add isopropyl alcohol and film-forming aid and disperse them evenly; add wetting agent, defoaming agent and thickener in sequence, disperse them evenly, filter and obtain water-based plastic baking paint.

2. The method for preparing a water-based plastic baking varnish with high anti-aging performance according to claim 1, characterized in that: The mass ratio of water-based resin, N,N-dimethylethanolamine, deionized water, isopropyl alcohol, film-forming aid, wetting agent, defoaming agent and thickener is 60-70: 0.4-0.8: 25-35: 1-2: 1-2: 0.7-1.5: 0.5-1: 0.5-1.

3. The method for preparing a water-based plastic baking varnish with high anti-aging performance according to claim 1, characterized in that: The wetting agent is a mixture of SN-3704 and BYK-346 in a mass ratio of 1:1; the defoaming agent is TEGO-902w; the film-forming aid is ethylene glycol butyl ether; and the thickener is BASF-3800.

4. The method for preparing a water-based plastic baking varnish with high anti-aging performance according to claim 1, characterized in that: The preparation method of the water-based resin comprises the following steps: S1: Add cyclohexane, n-hexanol and Triton X-100 to reaction bottle A, disperse evenly, add deionized water, disperse evenly, add ammonia water, tetraethyl orthosilicate and 3-(trihydroxysilyl)propylmethyl phosphate, stir for 18-24h, add anhydrous ethanol to break the emulsion, centrifuge and filter to obtain component 1; S2: Add epoxy resin, ethylene glycol butyl ether and n-butanol into reaction bottle B, control the temperature at 90-100°C, add component 1, keep warm and reflux for 1-3h to obtain component 2; S3: Add component 2, acrylic acid, butyl acrylate and methyl methacrylate into reaction bottle C, control the temperature at 110-120°C, add benzoyl peroxide, keep the reaction warm for 1-3h, control the temperature at 50-60°C, add distilled water to dilute to 30-40% solid content, adjust the pH to 8-9, and obtain water-based resin.

5. The method for preparing a water-based plastic baking varnish with high anti-aging performance according to claim 4, characterized in that: The ammonia water in S1 is 10-20wt% ammonia water, and the addition ratio of cyclohexane, n-hexanol, Triton X-100, deionized water, ammonia water, tetraethyl orthosilicate, 3-(trihydroxysilyl)propylmethyl phosphate, and anhydrous ethanol in S1 is 15mL: 3-5mL: 3-4.5g: 1-2mL: 0.2-0.3mL: 0.3-0.6mL: 0.1-0.15mL: 20-30mL.

6. The method for preparing a water-based plastic baking varnish with high anti-aging performance according to claim 4, characterized in that: The mass ratio of epoxy resin, ethylene glycol butyl ether, n-butanol and component one in S2 is 20:5-10:2.5-5:1-2.

7. The method for preparing a water-based plastic baking varnish with high anti-aging performance according to claim 4, characterized in that: The mass ratio of component 2, acrylic acid, butyl acrylate, methyl methacrylate and benzoyl peroxide in S3 is 100:10-15:2-3:3-5:0.5-1.

8. A water-based plastic baking varnish with high anti-aging performance, characterized in that: Prepared by the preparation method described in any one of claims 1 to 7.

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