A water-based plastic baking paint with high aging resistance and preparation method thereof

Abstract

The present invention discloses a water-based plastic baking varnish with high aging resistance and a preparation method thereof, relating to the technical field of water-based coatings. The present invention discloses a preparation method for a water-based plastic baking varnish, comprising the following steps: adding a water-based resin, N,N-dimethylethanolamine, and deionized water to a dispersion tank and uniformly dispersing the mixture; further adding isopropyl alcohol and a film-forming aid and uniformly dispersing the mixture; sequentially adding a wetting agent, a defoaming agent, and a thickener and uniformly dispersing the mixture; and filtering the mixture to obtain a water-based plastic baking varnish. The water-based resin prepared in the present application is obtained by copolymerizing a silica-modified epoxy resin with an acrylic resin. The water-based plastic baking varnish prepared in the present application has excellent aging resistance and good mechanical properties.

Description

Technical Field

[0001] The present 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 levels, people's pursuit of a higher quality of life is becoming stronger. A large proportion of metal and plastic parts used in daily life are coated with paint to achieve both aesthetic and protective properties. Traditional paints, typically oil-based polyester or acrylic / amino paints, can cause a range of environmental pollution during the coating process and pose health risks to paint operators.

[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 baking paints prepared with epoxy resins as the base material. 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 aging resistance and a preparation method thereof, to solve the following technical problems:

[0005] The existing paint prepared from the resin base material 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 appearance and fullness of the coating.

[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 aging resistance 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 and disperse them evenly. Filter and obtain water-based plastic baking paint.

[0009] As a further embodiment of the present invention, the mass ratio of the aqueous 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.

[0010] As a further embodiment 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 flask A and disperse evenly. Add deionized water and disperse evenly. Add ammonia water, tetraethyl orthosilicate, and 3-(trihydroxysilyl)propylmethyl phosphate. Stir for 18-24 hours. 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 to reaction flask B, control the temperature at 90-100°C, add component 1, and reflux for 1-3 hours to obtain component 2;

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

[0015] As a further embodiment of the present invention, the ammonia water in S1 is 10-20 wt% 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 15 mL: 3-5 mL: 3-4.5 g: 1-2 mL: 0.2-0.3 mL: 0.3-0.6 mL: 0.1-0.15 mL: 20-30 mL.

[0016] As a further embodiment 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 embodiment 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 paint with high anti-aging performance is prepared by any one of the above preparation methods.

[0019] Beneficial effects of the present invention:

[0020] This application first uses tetraethyl orthosilicate as a raw material to prepare silica. During the preparation process, 3-(trihydroxysilyl)propylmethyl phosphate is added to graft a large number of phosphate groups onto the silica surface, resulting in component one. The phosphate groups on component one are then reacted with epoxy resin for grafting, resulting in component two, which organically grafts silica onto the epoxy resin molecular chain. Component two is then copolymerized with acrylic acid and acrylate monomers. The epoxy ring undergoes an esterification ring-opening reaction with the added acrylic monomer, introducing an unsaturated double bond at the resin chain end. Free radicals at the epoxy chain end initiate polymerization, forming an acid-rich epoxy acrylic resin. This water-based resin combines the advantages of both epoxy and acrylic resins, with not only good adhesion but also excellent light and heat resistance. The baking varnish prepared in this application has excellent corrosion resistance and chemical resistance, excellent adhesion to a variety of substrates, and good flexibility. The grafting of component one and the copolymerized acrylic resin onto the epoxy resin molecular chain imparts high gloss and good gloss and color retention to the paint. DETAILED DESCRIPTION

[0021] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts 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 flask A and disperse evenly. Add 50 mL of deionized water and 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 break the emulsion. Centrifuge and filter to obtain component 1.

[0025] S2: Add 100g epoxy resin (E20), 25g ethylene glycol butyl ether, and 12.5g n-butanol to reaction flask B, control the temperature at 90-100°C, add 5g component 1, 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 to reaction flask 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: 750 mL of cyclohexane, 200 mL of n-hexanol, and 200 g of Triton X-100 were added to reaction flask A and dispersed evenly. 70 mL of deionized water was added and dispersed evenly. 12 mL of 20 wt% ammonia water, 20 mL of tetraethyl orthosilicate, and 6 mL of 3-(trihydroxysilyl)propylmethyl phosphate were added and stirred for 21 h. 1200 mL of anhydrous ethanol was added to break the emulsion. The mixture was centrifuged and filtered to obtain component 1.

[0030] S2: Add 100 g of epoxy resin (E20), 35 g of ethylene glycol butyl ether, and 17 g of n-butanol to reaction flask B, control the temperature at 100°C, add 7 g of component 1, and reflux for 3 h 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 to reaction flask 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 flask A and disperse evenly. Add 100 mL of deionized water and 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 break the emulsion. 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 to reaction flask B, control the temperature at 100°C, add 10g of component 1, and reflux for 3h to obtain component 2;

[0036] S3: Add 100g of component 2, 15g of acrylic acid, 3g of butyl acrylate, and 5g of methyl methacrylate to reaction flask 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 the pH to 8, and obtain a water-based resin.

[0037] Example 4

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

[0039] 70 g of the aqueous 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 isopropyl alcohol and 2 g of ethylene glycol butyl ether were further 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 aging resistance comprises the following steps:

[0042] 70 g of the aqueous resin prepared in Example 2, 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 isopropyl alcohol and 2 g of ethylene glycol butyl ether were further 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.

[0043] Example 6

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

[0045] 70 g of the aqueous resin prepared in Example 3, 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 isopropyl alcohol and 2 g of ethylene glycol butyl ether were further 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.

[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 flask A and disperse evenly. Add 50 mL of deionized water and disperse evenly. Add 10 mL of 20 wt% ammonia water and 15 mL of tetraethyl orthosilicate and stir for 18 h. Add 1000 mL of anhydrous ethanol to break the emulsion, centrifuge, and filter to obtain component 1.

[0049] S2: Add 100g epoxy resin (E20), 25g ethylene glycol butyl ether, and 12.5g n-butanol to reaction flask B, control the temperature at 90-100°C, add 5g component 1, 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 to reaction flask 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 of epoxy resin (E20), 10g of acrylic acid, 2g of butyl acrylate, and 3g of methyl methacrylate to reaction flask 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.

[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 flask A and disperse evenly. Add 50 mL of deionized water and 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 break the emulsion. Centrifuge and filter to obtain component 1.

[0057] S2: Add 100g epoxy resin (E20), 25g ethylene glycol butyl ether, and 12.5g n-butanol to reaction flask B, control the temperature at 90-100°C, add 5g component 1, 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 to reaction flask 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, Comparative Example 5 is simply a case where the aqueous resin prepared in Example 1 added in Example 4 is replaced by an equal amount of the aqueous resin prepared in Comparative Example 2, and the remaining components and preparation method are completely consistent with 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 the aqueous resin prepared in Comparative Example 3 in equal amount, and the remaining components and preparation method are completely consistent with Example 4.

[0065] Performance testing:

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

[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: The test was conducted in accordance with 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]

[0071]

[0072] It can be seen from Table 1 that the baking varnish prepared by adding the water-based resin prepared in this application to the paint has excellent mechanical properties.

[0073] (3) Rubber test: carried out according to GB / T 1768-79 coating abrasion resistance determination method; the test results are shown in Table 2;

[0074] (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;

[0075] (5) Isopropyl alcohol resistance: tested according to ASTM D5402-06 (2011) “Determination of Solvent Wipe Resistance of Organic Coatings by Solvent Wipe Method”; the test results are shown in Table 2;

[0076] Table 2: Statistics of performance test data of Examples 4-6 and Comparative Examples 4-6

[0077]

[0078] As can be seen from Table 2, the baking varnish prepared in this application has good solvent resistance and friction resistance.

[0079] (6) Glossiness: 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 h, each aging cycle is 12 h, and the first 8 h is UV radiation with a wavelength of 340 nm and an irradiation intensity of 0.89 W˙m -2 , the internal temperature of the aging box is 60℃, and the last 4 hours 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 is the gloss loss rate, %; A0 is the gloss value before aging; A1 is the gloss value before aging;

[0083] Color difference ΔE=[(ΔL) 2 +(Δa) 2 +(Δb) 2 ] 1 / 2

[0084] Where, L-lightness; a-red-green color index; b-yellow-blue color index;

[0085] Table 3: Statistical table of aging resistance test data of Examples 4-6 and Comparative Examples 4-6

[0086] 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

[0087] As can be seen from Table 3, the baking paint 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 paint prepared in the present application also has excellent aging resistance.

[0088] An embodiment of the present invention has been described in detail above. However, the content described is only a preferred embodiment of the present invention and should not be considered to limit the scope of implementation of the present invention.

[0089] All equivalent changes and improvements made within the scope of the present invention shall still belong to this invention.

[0090] The invention is within the scope of the patent.

Claims

1. A method for preparing a water-based plastic baking varnish with high aging resistance, 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 and disperse them evenly, filter and obtain water-based plastic baking paint; The preparation method of the water-based resin comprises the following steps: S1: Add cyclohexane, n-hexanol, and Triton X-100 to reaction flask A and disperse evenly. Add deionized water and disperse evenly. Add ammonia water, tetraethyl orthosilicate, and 3-(trihydroxysilyl)propylmethyl phosphate. Stir for 18-24 hours. 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 to reaction flask B, control the temperature at 90-100°C, add component 1, and reflux for 1-3 hours to obtain component 2; S3: Add component 2, acrylic acid, butyl acrylate, and methyl methacrylate to reaction flask C, control the temperature at 110-120°C, add benzoyl peroxide, keep the reaction warm for 1-3 hours, control the temperature at 50-60°C, add distilled water to dilute to a solid content of 30-40%, adjust the pH to 8-9, and obtain a water-based resin.

2. The method for preparing a water-based plastic baking varnish with high aging resistance 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 aging resistance 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 aging resistance according to claim 1, characterized in that: The ammonia water in S1 is 10-20 wt% 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 15 mL: 3-5 mL: 3-4.5 g: 1-2 mL: 0.2-0.3 mL: 0.3-0.6 mL: 0.1-0.15 mL: 20-30 mL.

5. The method for preparing a water-based plastic baking varnish with high aging resistance according to claim 1, 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.

6. The method for preparing a water-based plastic baking varnish with high aging resistance according to claim 1, 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.

7. A water-based plastic baking paint with high aging resistance, characterized in that: Prepared by the preparation method according to any one of claims 1 to 6.

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