Impact-resistant powder coating and preparation method thereof

Abstract

The invention discloses an impact-resistant powder coating and a preparation method thereof, which relates to the field of powder coatings, and comprises the following raw materials in parts by weight: 40-60 parts of modified polyester resin, 10-20 parts of polytetrafluoroethylene, 5-10 parts of barium sulfate, 10-20 parts of mica powder, 5-15 parts of titanium dioxide, 1-2 parts of leveling agent, and 5-15 parts of curing agent; the modified polyester resin is made of the following raw materials: polyester resin, butyl acetate, methyl isobutyl ketone, basalt, and silane coupling agent. The application has the effect of improving the impact resistance of the powder coating.

Description

Technical Field

[0001] The invention relates to the field of powder coatings, in particular to an impact-resistant powder coating and a preparation method thereof. Background Art

[0002] Powder coating is a solvent-free solid powder coating with the advantages of environmental protection, energy saving and high efficiency. It is widely used in home appliances, construction, automobiles and other fields.

[0003] However, with the development of society, people have higher and higher requirements for the performance of coatings. Although powder coatings have good thermal stability, they are often damaged and scratched due to physical collision or friction during the application process, and can no longer provide a good physical and chemical protection effect on the coated substrate. Summary of the invention

[0004] In order to improve the impact resistance of powder coatings, the present application provides an impact-resistant powder coating and a preparation method thereof.

[0005] In the first aspect, the impact-resistant powder coating provided by the present application adopts the following technical method:

[0006] An impact-resistant powder coating comprises the following raw materials in parts by weight: 40-60 parts of modified polyester resin, 10-20 parts of polytetrafluoroethylene, 5-10 parts of barium sulfate, 10-20 parts of mica powder, 5-15 parts of titanium dioxide, 1-2 parts of leveling agent, and 5-15 parts of curing agent; the modified polyester resin is made of the following raw materials: polyester resin, butyl acetate, methyl isobutyl ketone, basalt, and silane coupling agent.

[0007] By adopting the above technical scheme, the present application uses titanium dioxide, barium sulfate and mica powder as fillers, which are filled between polytetrafluoroethylene and polyester resin, so that the powder coating forms a dense three-dimensional network structure after forming a paint film, thereby improving the impact resistance of the powder coating. Polytetrafluoroethylene and titanium dioxide can improve the chemical corrosion resistance of the powder coating, so that the powder coating has good salt spray resistance after forming a paint film.

[0008] Preferably, the modified polyester resin is prepared by mixing 20-40 parts by weight of polyester resin with 10-20 parts by weight of butyl acetate and 5-10 parts by weight of methyl isobutyl ketone, and then adding 10-20 parts by weight of basalt and 5-10 parts by weight of silane coupling agent, mixing and stirring to obtain the modified polyester resin.

[0009] By adopting the above technical scheme, the present application grafts the surface of basalt through the reaction of silane coupling agent with hydroxyl groups on the surface of basalt. The grafted basalt is mixed with polyester resin as a filler, and then mixed with butyl acetate and methyl isobutyl ketone to effectively improve the adhesion and impact resistance of the powder coating.

[0010] Preferably, the weight ratio of the polyester resin, basalt and silane coupling agent is 1:(0.6-0.64):(0.2-0.24).

[0011] By adopting the above technical scheme, when the polyester resin, basalt and silane coupling agent are in a specific weight ratio, the silane coupling agent forms an effective interface bonding between the polyester resin and the basalt, which helps the polyester resin to form a strong and wear-resistant special layer in the powder coating, thereby improving the impact resistance and adhesion of the powder coating.

[0012] Preferably, the mica powder is modified mica powder, and the preparation method of the modified mica powder is: add 10-20 parts by weight of mica powder to 50-70 parts by weight of anhydrous ethanol for ultrasonic dispersion, add 2-8 parts by weight of KH560, 5-10 parts by weight of polyamide wax, and 5-10 parts by weight of diisononyl phthalate in sequence and continue stirring, vacuum dehydrate and then dry to obtain the modified mica powder.

[0013] By adopting the above technical scheme, the present application modifies one of the fillers of the powder coating, and the modified mica powder can improve the rheological properties of the mica powder. Active groups such as amide groups, ester groups, and hydroxyl groups are introduced into the components, and the mica powder is evenly distributed in the components by physical blending, thereby improving the impact resistance and salt spray resistance of the paint film formed by the powder coating.

[0014] Preferably, the weight ratio of the mica powder, KH560, polyamide wax and diisononyl phthalate is (3-3.6):1:(1.04-1.12):(1.68-1.84).

[0015] By adopting the above technical solution, when mica powder, KH560, polyamide wax and diisononyl phthalate are in a specific weight ratio, the four work synergistically to improve the impact resistance and salt spray resistance of the powder coating.

[0016] Preferably, the weight ratio of the modified polyester resin, polytetrafluoroethylene, modified mica powder and titanium dioxide is 1: (0.3-0.32): (0.36-0.4): (0.12-0.14).

[0017] By adopting the above technical scheme, when polyester resin, polytetrafluoroethylene, modified mica powder and titanium dioxide are combined together, the modified mica powder and titanium dioxide as fillers can improve the impact resistance of the powder coating, so that the powder coating has good weather resistance. At the same time, the polyester resin and polytetrafluoroethylene can improve the coating performance of the powder coating. The combination of the four is conducive to further improving the structural stability of the powder coating during transportation, packaging or long-term storage, and has a promoting effect on improving the impact resistance of the paint film formed by the powder coating, and improving the adhesion and chemical corrosion resistance of the powder coating.

[0018] Preferably, the acid value of the polyester resin is 25-30 mgKOH / g.

[0019] By adopting the above technical solution and selecting a polyester resin with a suitable acid value, the adhesion between the powder coating and the substrate can be improved, so that the powder coating has better chemical resistance and can better resist salt spray corrosion.

[0020] Preferably, the curing agent is one of dicyandiamide and isophthalic acid dihydrazide.

[0021] By adopting the above technical solution and selecting a suitable curing agent, it is helpful to accelerate the cross-linking reaction with the resin matrix, thereby improving the impact resistance of the powder coating.

[0022] In a second aspect, the present application provides a method for preparing an impact-resistant powder coating using the following technical solution:

[0023] A method for preparing an impact-resistant powder coating comprises the following steps: mixing and stirring a modified polyester resin, polytetrafluoroethylene, barium sulfate, mica powder, titanium dioxide, a leveling agent and a curing agent, heating, melting and extruding, cooling after extrusion, tabletting, crushing, grinding and screening to obtain the impact-resistant powder coating.

[0024] By adopting the above technical solution, a powder coating with good impact resistance can be prepared by simply mixing the components and then performing simple processes such as melt extrusion.

[0025] In summary, this application has the following beneficial technical effects:

[0026] 1. The present application uses titanium dioxide, barium sulfate and mica powder as fillers, which are filled between polytetrafluoroethylene and polyester resin, so that the powder coating forms a dense three-dimensional network structure after forming a paint film. Polytetrafluoroethylene and titanium dioxide can improve the chemical corrosion resistance of the powder coating, so that the powder coating has good salt spray resistance after forming a paint film.

[0027] 2. When polyester resin, polytetrafluoroethylene, modified mica powder and titanium dioxide are used together, modified mica powder and titanium dioxide as fillers can improve the impact resistance of powder coatings and make powder coatings have good weather resistance. At the same time, polyester resin and polytetrafluoroethylene can improve the coating performance of powder coatings. The combination of the four is conducive to further improving the structural stability of powder coatings during transportation, packaging or long-term storage, and has a promoting effect on improving the impact resistance of the paint film formed by powder coatings, and improving the adhesion and chemical corrosion resistance of powder coatings. DETAILED DESCRIPTION

[0028] The present application is further described in detail below in conjunction with embodiments and comparative examples.

[0029] Example

[0030] Example 1

[0031] A method for preparing an impact-resistant powder coating comprises the following steps:

[0032] 40g of modified polyester resin, 10g of polytetrafluoroethylene, 5g of barium sulfate, 10g of mica powder, 5g of titanium dioxide, 1g of leveling agent and 5g of curing agent were put into a mixer and stirred at a temperature of 75°C for 15 minutes, transferred to a screw extruder, heated to 120°C, and melt-extruded at a speed of 800rpm. After extrusion, it was cooled to room temperature, tableted, crushed, ground with an ACM mill, and screened through a 220-mesh sieve to obtain an impact-resistant powder coating.

[0033] The polyester resin used is Wanqing DC191 with an acid value of 25 mgKOH / g; the polytetrafluoroethylene used is Shanghai Qiansen International Trade Co., Ltd., with a brand name of LB-202; the leveling agent is Deqian Levaslip 872; and the curing agent is isophthalic acid 2-hydrazide.

[0034] The preparation method of the modified polyester resin is as follows: 20 g of polyester resin, 10 g of butyl acetate and 5 g of methyl isobutyl ketone are added into a ball mill, mixed and ball milled for 1 hour, 10 g of basalt and 5 g of silane coupling agent KH550 are added, ultrasonically dispersed for 20 minutes, and ball milling is continued for 1.5 hours to obtain the modified polyester resin.

[0035] Example 2

[0036] A method for preparing an impact-resistant powder coating comprises the following steps:

[0037] 60g of modified polyester resin, 20g of polytetrafluoroethylene, 10g of barium sulfate, 20g of mica powder, 15g of titanium dioxide, 2g of leveling agent and 15g of curing agent were put into a mixer and stirred at a temperature of 75°C for 15 minutes, transferred to a screw extruder, heated to 120°C, and melt-extruded at a speed of 800rpm. After extrusion, it was cooled to room temperature, tableted, crushed, ground with an ACM mill, and screened through a 220-mesh sieve to obtain an impact-resistant powder coating.

[0038] The polyester resin used was Wanqing DC191 with an acid value of 25 mgKOH / g; the polytetrafluoroethylene used was from Shanghai Qiansen International Trade Co., Ltd. with a brand name of LB-202; the leveling agent was Deqian Levaslip 872; and the curing agent was dicyandiamide.

[0039] The preparation method of the modified polyester resin is as follows: 20 g of polyester resin, 10 g of butyl acetate and 5 g of methyl isobutyl ketone are added into a ball mill, mixed and ball milled for 1 hour, 10 g of basalt and 5 g of silane coupling agent KH550 are added, ultrasonically dispersed for 20 minutes, and ball milling is continued for 1.5 hours to obtain the modified polyester resin.

[0040] Example 3

[0041] A method for preparing an impact-resistant powder coating comprises the following steps:

[0042] The modified polyester resin, polytetrafluoroethylene, barium sulfate, mica powder, titanium dioxide, leveling agent and curing agent were put into a mixer and stirred at a temperature of 75°C for 15 minutes, transferred to a screw extruder, heated to 120°C, and melt-extruded at a speed of 800 rpm. After extrusion, the mixture was cooled to room temperature, tableted, crushed, ground with an ACM mill, and screened through a 220-mesh sieve to obtain an impact-resistant powder coating.

[0043] The polyester resin used is Wanqing DC191 with an acid value of 25 mgKOH / g; the polytetrafluoroethylene used is Shanghai Qiansen International Trade Co., Ltd., with a brand name of LB-202; the leveling agent is Deqian Levaslip 872; and the curing agent is isophthalic acid 2-hydrazide.

[0044] The preparation method of the modified polyester resin is as follows: 20 g of polyester resin, 10 g of butyl acetate and 5 g of methyl isobutyl ketone are added into a ball mill, mixed and ball milled for 1 hour, 10 g of basalt and 5 g of silane coupling agent KH550 are added, ultrasonically dispersed for 20 minutes, and ball milling is continued for 1.5 hours to obtain the modified polyester resin.

[0045] Example 4

[0046] A method for preparing an impact-resistant powder coating, which is different from Example 3 in that: a method for preparing a modified polyester resin is as follows: 40 g of a polyester resin, 20 g of butyl acetate and 10 g of methyl isobutyl ketone are added to a ball mill, mixed and ball milled for 1 hour, 20 g of basalt and 10 g of a silane coupling agent KH550 are added, ultrasonically dispersed for 20 minutes, and ball milling is continued for 1.5 hours to obtain the modified polyester resin.

[0047] Example 5

[0048] A method for preparing an impact-resistant powder coating, which is different from Example 3 in that: in the process of preparing the modified polyester resin, the input amount of the polyester resin is 30g, the input amount of the basalt is 18g, and the input amount of the silane coupling agent KH550 is 6g.

[0049] Example 6

[0050] A method for preparing an impact-resistant powder coating, which is different from Example 3 in that: in the process of preparing the modified polyester resin, the input amount of the polyester resin is 30g, the input amount of the basalt is 19.2g, and the input amount of the silane coupling agent KH550 is 7.2g.

[0051] Example 7

[0052] A method for preparing an impact-resistant powder coating, which is different from Example 6 in that an equal amount of mica powder is replaced with modified mica powder, and the preparation method of the modified mica powder is as follows: 10g of mica powder is added to 50g of anhydrous ethanol for ultrasonic dispersion for 30min, 2g of KH560, 5g of polyamide wax, and 5g of diisononyl phthalate are added in sequence, and stirring is continued for 10min at a temperature of 60°C, and after vacuum dehydration, the mixture is dried at a temperature of 90°C for 2h to obtain the modified mica powder. The polyamide wax is selected from Ruike Chemical RKZ3021.

[0053] Example 8

[0054] A method for preparing an impact-resistant powder coating, which is different from Example 6 in that an equal amount of mica powder is replaced with modified mica powder, and the preparation method of the modified mica powder is as follows: 20g of mica powder is added to 70g of anhydrous ethanol for ultrasonic dispersion for 30min, 8g of KH560, 10g of polyamide wax, and 10g of diisononyl phthalate are added in sequence and stirred at 60°C, and then vacuum dehydrated and dried at 90°C for 2h to obtain modified mica powder. Polyamide wax is purchased from Ruike Chemical RKZ3021.

[0055] Example 9

[0056] A method for preparing an impact-resistant powder coating, which is different from Example 8 in that the input amount of mica powder is 15g, the input amount of KH560 is 5g, the input amount of polyamide wax is 5.2g, and the input amount of diisononyl phthalate is 8.4g.

[0057] Example 10

[0058] A method for preparing an impact-resistant powder coating, which is different from Example 8 in that the input amount of mica powder is 18 g, the input amount of KH560 is 5 g, the input amount of polyamide wax is 5.6 g, and the input amount of diisononyl phthalate is 9.2 g.

[0059] Embodiment 11

[0060] A method for preparing an impact-resistant powder coating, which is different from Example 10 in that the input amount of modified polyester resin is 50g, the input amount of polytetrafluoroethylene is 15g, the input amount of modified mica powder is 18g, and the input amount of titanium dioxide is 6g.

[0061] Example 12

[0062] A method for preparing an impact-resistant powder coating, which is different from Example 10 in that the input amount of modified polyester resin is 50g, the input amount of polytetrafluoroethylene is 16g, the input amount of modified mica powder is 20g, and the input amount of titanium dioxide is 7g.

[0063] Comparative Example

[0064] Comparative Example 1

[0065] A method for preparing an impact-resistant powder, which differs from Example 3 in that the modified polyester resin is replaced by an equal amount of a commercially available polyester resin, Hebei Gujia Technology Co., Ltd., with a brand name of 3301 and an acid value of 15 mgKOH / g

[0066] Comparative Example 2

[0067] A method for preparing impact-resistant powder, which is different from Example 3 in that the modified polyester resin is replaced by an equal amount of epoxy resin, and the epoxy resin purchased from Hebei Maorong Anticorrosion Materials Co., Ltd. is brand e44.

[0068] Comparative Example 3

[0069] A method for preparing impact-resistant powder, which is different from Example 3 in that an equal amount of polytetrafluoroethylene is replaced with epoxy resin, and the epoxy resin purchased from Hebei Maorong Anticorrosion Materials Co., Ltd. is brand e44.

[0070] Comparative Example 4

[0071] A method for preparing impact-resistant powder, which is different from Example 3 in that an equal amount of mica powder is replaced by quartz powder.

[0072] Performance testing:

[0073] Adhesion test: The powder coatings prepared in Examples 1-12 and Comparative Examples 1-4 were tested according to GB / T9286-2021.

[0074] Salt spray resistance: The powder coatings prepared in Examples 1-12 and Comparative Examples 1-4 were tested according to GB / T2423.17-2008.

[0075] Impact resistance test: According to GB / T1732, the powder coatings prepared in Examples 1-12 and Comparative Examples 1-4 were coated on a flat glass, left standing at 95°C for 12 min, then heated to 190°C and left standing for 22 min, and naturally cooled to room temperature for testing.

[0076] Adhesion Salt spray resistance Impact resistance kg·cm Example 1 Level 1 Corrosion depth <1mm 38.1 Example 2 Level 1 Corrosion depth <1mm 38.2 Example 3 Level 1 Corrosion depth <1mm 38.2 Example 4 Level 1 Corrosion depth <1mm 38.3 Example 5 Level 1 Corrosion depth <1mm 38.7 Example 6 Level 1 Corrosion depth <1mm 38.8 Example 7 Level 0 Corrosion depth <1mm 39.3 Example 8 Level 0 Corrosion depth <1mm 39.4 Example 9 Level 0 Corrosion depth <1mm 39.3 Example 10 Level 0 Corrosion depth <1mm 39.2 Embodiment 11 Level 0 Corrosion depth <1mm 39.5 Example 12 Level 0 Corrosion depth <1mm 39.6 Comparative Example 1 Level 1 Corrosion depth>1mm 35.5 Comparative Example 2 Level 1 Corrosion depth>1mm 35.1 Comparative Example 3 Level 1 Corrosion depth>1mm 34.2 Comparative Example 4 Level 2 Corrosion depth <1mm 29.8

[0077] According to the data comparison of Examples 1-3 and Comparative Examples 1-4, the present application uses titanium dioxide, barium sulfate and mica powder as fillers, which are filled between polytetrafluoroethylene and polyester resin, so that the powder coating forms a dense three-dimensional network structure after forming a paint film. Polytetrafluoroethylene and titanium dioxide can improve the chemical corrosion resistance of the powder coating, so that the powder coating has good salt spray resistance after forming a paint film.

[0078] According to the data comparison of Examples 3-6, the present application grafts the surface of basalt by reacting a silane coupling agent with the hydroxyl groups on the surface of basalt. The grafted basalt is mixed with a polyester resin as a filler, and then mixed with butyl acetate and methyl isobutyl ketone to effectively improve the adhesion and impact resistance of the powder coating.

[0079] According to the data comparison of Examples 6-8, the present application modifies one of the fillers of the powder coating, and the modified mica powder can improve the rheological properties of the mica powder. Active groups such as amide groups, ester groups, and hydroxyl groups are introduced into the components, and the mica powder is evenly distributed in the components by physical blending, thereby improving the impact resistance and salt spray resistance of the paint film formed by the powder coating.

[0080] According to the data comparison of Examples 8-10, when mica powder, KH560, polyamide wax and diisononyl phthalate are in a specific weight ratio, the four work synergistically to improve the impact resistance and salt spray resistance of the powder coating.

[0081] According to the data comparison of Examples 10-12, when polyester resin, polytetrafluoroethylene, modified mica powder and titanium dioxide are used together, modified mica powder and titanium dioxide as fillers can improve the impact resistance of the powder coating, so that the powder coating has good weather resistance. At the same time, polyester resin and polytetrafluoroethylene can improve the coating performance of the powder coating. The combination of the four is conducive to further improving the structural stability of the powder coating during transportation, packaging or long-term storage, and has a promoting effect on improving the impact resistance of the paint film formed by the powder coating, and improving the adhesion and chemical corrosion resistance of the powder coating.

[0082] This specific implementation manner is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the specific implementation manner as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. An impact-resistant powder coating, Features: The invention comprises the following raw materials in parts by weight: 40-60 parts of modified polyester resin, 10-20 parts of polytetrafluoroethylene, 5-10 parts of barium sulfate, 10-20 parts of mica powder, 5-15 parts of titanium dioxide, 1-2 parts of leveling agent and 5-15 parts of curing agent; the modified polyester resin is made from the following raw materials: polyester resin, butyl acetate, methyl isobutyl ketone, basalt and silane coupling agent; the preparation method of the modified polyester resin is as follows: 20-40 parts by weight of polyester resin are mixed with 10-20 parts by weight of butyl acetate and 5-10 parts by weight of methyl isobutyl ketone, and then 10-20 parts by weight of basalt and 5-10 parts by weight of silane coupling agent are added. The modified polyester resin is obtained by mixing and stirring the mica powder; the mica powder is modified mica powder, and the preparation method of the modified mica powder is as follows: 10-20 parts by weight of mica powder is added to 50-70 parts by weight of anhydrous ethanol for ultrasonic dispersion, 2-8 parts by weight of KH560, 5-10 parts by weight of polyamide wax, and 5-10 parts by weight of diisononyl phthalate are added in sequence and continued to be stirred, and vacuum dehydration and drying are performed to obtain the modified mica powder; the weight ratio of the modified polyester resin, polytetrafluoroethylene, modified mica powder and titanium dioxide is 1: (0.3-0.32): (0.36-0.4): (0.12-0.14).

2. An impact-resistant powder coating according to claim 1, Features: The weight ratio of the polyester resin, basalt and silane coupling agent is 1: (0.6-0.64): (0.2-0.24).

3. An impact-resistant powder coating according to claim 1, Features: The weight ratio of the mica powder, KH560, polyamide wax and diisononyl phthalate is (3-3.6):1:(1.04-1.12):(1.68-1.84).

4. An impact-resistant powder coating according to claim 1, Features: The acid value of the polyester resin is 25-30 mgKOH / g.

5. The impact-resistant powder coating according to claim 1, Features: The curing agent is dicyandiamide.

6. A method for preparing an impact-resistant powder coating, Features: The method for preparing the impact-resistant powder coating according to any one of claims 1 to 5 comprises the following steps: mixing and stirring modified polyester resin, polytetrafluoroethylene, barium sulfate, mica powder, titanium dioxide, a leveling agent and a curing agent, heating and melting and extruding, cooling after extrusion, tabletting, crushing, grinding and screening to obtain the impact-resistant powder coating.