Powder coating for nonmetal coating and preparation method thereof

Abstract

The invention relates to the technical field of coatings, and provides a powder coating for nonmetal coating and a preparation method thereof. The powder coating for nonmetal coating comprises the following components in parts by mass: 60-70 parts of carboxyl-terminated polyester resin, 5-8 parts of a curing agent, 1-3 parts of a curing accelerator, 10-20 parts of a modified filler, 1-3 parts of a leveling agent, 2-3 parts of benzoin and 10-15 parts of a catalyst, and the modified filler comprises a vinyl silane modified filler and a hydroxyl-containing compound modified filler in a mass ratio of 1: 9-9: 1. Through the technical scheme, the problems of poor wear resistance and low hardness of powder coatings in related technologies are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of coatings, and in particular to a powder coating for non-metallic coating and a preparation method thereof. Background Art

[0002] As the concept of environmental protection continues to gain popularity, powder coatings have developed rapidly. On the one hand, powder coatings do not contain organic solvents, which is conducive to storage and transportation, and is environmentally friendly and pollution-free; on the other hand, due to the simple process and high production efficiency, they are widely used in non-metallic products such as glass, wood, and concrete.

[0003] At present, most powder coatings are made of polyester resin as the important film-forming material, and are prepared in combination with various additives such as curing agents and fillers. The fillers give the powder coatings a certain wear resistance and hardness. However, since the fillers are inorganic substances, they have poor compatibility with polyester resins, are prone to self-agglomeration, and are not easy to disperse evenly in the coating, resulting in the powder coatings having unsatisfactory wear resistance and hardness. Summary of the invention

[0004] The invention provides a powder coating for non-metallic coating and a preparation method thereof, which solves the problems of poor wear resistance and low hardness of the powder coating in the related art.

[0005] The technical solution of the present invention is as follows: A powder coating for non-metallic coating comprises the following components in parts by mass: 60-70 parts of terminal carboxyl polyester resin, 5-8 parts of curing agent, 1-3 parts of curing accelerator, 10-20 parts of modified filler, 1-3 parts of leveling agent, 2-3 parts of benzoin, and 10-15 parts of catalyst, wherein the modified filler comprises a vinyl silane modified filler and a hydroxyl compound modified filler in a mass ratio of 1:9-9:1.

[0006] As a further technical solution, 3 times the mass of the vinyl silane modified filler is ≤7 times the mass of the hydroxyl compound modified filler.

[0007] The present invention limits the mass of the filler modified by 3 times vinyl silane to ≤7 times the mass of the filler modified by the hydroxyl compound, thereby further improving the wear resistance of the powder coating.

[0008] As a further technical solution, the mass ratio of the vinyl silane modified filler to the hydroxy compound modified filler is 1:1 to 3:7.

[0009] The present invention limits the mass ratio of the vinyl silane modified filler to the hydroxy compound modified filler to 1:1-3:7, thereby further improving the wear resistance and hardness of the powder coating.

[0010] As a further technical solution, the raw materials of the vinyl silane modified filler include vinyl silane and filler in a mass ratio of 0.5 to 1:10.

[0011] In the present invention, the vinyl silane may be any silane containing a vinyl group, for example, it may be one or more of silane coupling agent YDH-171, silane coupling agent KH-1706, silane coupling agent KH-171, and silane coupling agent KH-172.

[0012] As a further technical solution, the raw material containing the hydroxy compound modified filler includes a hydroxy compound and a filler in a mass ratio of 0.5 to 1.5:20.

[0013] The hydroxyl group-containing compound in the present invention may be any compound containing a hydroxyl group, for example, it may be one or both of 4-hydroxybenzoic acid-2-hydroxyethyl ester and 4-(p-hydroxyphenyl)-2-butanol.

[0014] As a further technical solution, the preparation method of the vinyl silane modified filler comprises the following steps: dispersing the filler evenly in water, adding vinyl silane to continue dispersing, filtering, and drying to obtain the vinyl silane modified filler.

[0015] As a further technical solution, the preparation method of the filler modified by hydroxyl compound comprises the following steps: uniformly mixing the hydroxyl compound with the solvent, adding the filler and continuing to mix, filtering, and drying to obtain the filler modified by hydroxyl compound.

[0016] As a further technical solution, the fillers independently include one or both of quartz powder and talcum powder.

[0017] As a further technical solution, the catalyst includes one or two of methyltriphenylphosphonium bromide and butyltriphenylphosphonium chloride.

[0018] The present invention also proposes a method for preparing a powder coating for non-metallic coating, comprising the following steps: uniformly mixing a carboxyl-terminated polyester resin, a vinyl silane-modified filler, a leveling agent, and benzoin, adding a hydroxyl compound-modified filler and continuing to mix, and finally adding a curing agent, a curing accelerator, and a catalyst and mixing, followed by extrusion, tableting, and crushing to obtain a powder coating.

[0019] The present invention also provides a method for preparing a powder coating for non-metallic coating, and the wear resistance of the powder coating is further improved by limiting the adding sequence of the vinyl silane modified filler and the hydroxy compound modified filler.

[0020] The working principle and beneficial effects of the present invention are: The invention uses carboxyl-terminated polyester resin, curing agent, curing accelerator, modified filler, leveling agent, benzoin and catalyst as raw materials, wherein the modified filler includes vinyl silane modified filler and hydroxyl compound modified filler, and provides a powder coating for non-metallic coating. The vinyl silane modified filler and the hydroxyl compound modified filler are used together. Since the filler is modified by vinyl silane, the surface of the filler has -C=C-, which not only improves the inorganic property of the filler surface, but also the carbon-carbon double bonds on the surface can form hydrogen bonds with the carboxyl groups in the carboxyl-terminated polyester resin; after the filler is modified by the hydroxyl compound, the surface of the filler has hydroxyl groups, which improves the inorganic property of the filler surface, and the hydroxyl groups on the surface can form hydrogen bonds with the ester groups, thereby improving the wear resistance and hardness of the powder coating. DETAILED DESCRIPTION

[0021] The following will be combined with the embodiments of the present invention to clearly and completely describe 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] The parameters of the raw materials in the following examples and comparative examples are as follows: The carboxyl-terminated polyester resin is Syntema Albester 5070; The curing agent is powder coating curing agent TGIC; The curing accelerator is 2-heptadecylimidazole; The leveling agent is Estron Resiflow PL-200; The catalyst is methyltriphenylphosphonium bromide; The particle size of quartz powder is 5000 mesh and the silica content is 99.5%; The particle size of talcum powder is 5000 mesh.

[0023] Example 1 S1. After 20 parts of quartz powder is uniformly stirred in 200 parts of water, 2 parts of KH-172 are added and stirred at 55°C for 2 hours, filtered and dried to obtain a vinyl silane modified filler; S2, after dissolving 1.5 parts of 2-hydroxyethyl 4-hydroxybenzoate in 100 parts of dimethyl sulfoxide by stirring, adding 20 parts of quartz powder and continuing to stir, filtering, and drying to obtain a filler modified with a hydroxyl compound; S3. Mix 60 parts of terminal carboxyl polyester resin, 9 parts of vinyl silane modified filler, 1 part of leveling agent and 2 parts of benzoin, stir at 350r / min for 30min, add 1 part of modified filler containing hydroxyl compound and continue stirring for 15min, finally add 5 parts of curing agent, 1 part of curing accelerator and 10 parts of catalyst, mix at 700r / min and stir for 5min, transfer to a twin-screw extruder for extrusion, tablet, and crush to 10μm to obtain powder coating.

[0024] Example 2 S1. After 20 parts of talc powder is uniformly stirred in 200 parts of water, 1 part of KH-172 is added and stirred at 55°C for 2 hours, filtered and dried to obtain a vinyl silane modified filler; S2, after dissolving 0.5 parts of 4-(p-hydroxyphenyl)-2-butanol in 100 parts of dimethyl sulfoxide by stirring, adding 20 parts of talcum powder and continuing to stir, filtering, and drying to obtain a filler modified with a hydroxyl compound; S3. Mix 70 parts of terminal carboxyl polyester resin, 2 parts of vinyl silane modified filler, 3 parts of leveling agent and 3 parts of benzoin, stir at 350r / min for 30min, add 18 parts of hydroxyl compound modified filler and continue stirring for 15min, finally add 8 parts of curing agent, 3 parts of curing accelerator and 15 parts of catalyst, mix at 700r / min and stir for 5min, transfer to a twin-screw extruder for extrusion, tablet, and crush to 10μm to obtain powder coating.

[0025] Example 3 The only difference from Example 1 is that S3 contains 7 parts of vinyl silane modified filler and 3 parts of hydroxy compound modified filler.

[0026] Example 4 The only difference from Example 1 is that S3 contains 5 parts of vinyl silane modified filler and 5 parts of hydroxy compound modified filler.

[0027] Example 5 The only difference from Example 1 is that S3 contains 3 parts of vinyl silane modified filler and 7 parts of hydroxy compound modified filler.

[0028] Example 6 The only difference from Example 1 is that S3 contains 1 part of vinyl silane modified filler and 9 parts of hydroxy compound modified filler.

[0029] Example 7 The only difference from Example 1 is: S3. Mix 60 parts of terminal carboxyl polyester resin, 3 parts of vinyl silane modified filler, 7 parts of hydroxyl compound modified filler, 1 part of leveling agent and 2 parts of benzoin, and stir at 350 r / min for 45 minutes. Then add 5 parts of curing agent, 1 part of curing accelerator and 10 parts of catalyst, and mix at 700 r / min and stir for 5 minutes. Then transfer to a twin-screw extruder for extrusion, tableting and crushing to 10 μm to obtain a powder coating.

[0030] Example 8 The only difference from Example 1 is: S3. Mix 60 parts of terminal carboxyl polyester resin, 7 parts of filler modified with hydroxyl compounds, 1 part of leveling agent and 2 parts of benzoin, stir at 350r / min for 30 minutes, add 3 parts of vinyl silane modified filler and continue stirring for 15 minutes, finally add 5 parts of curing agent, 1 part of curing accelerator and 10 parts of catalyst, mix at 700r / min and stir for 5 minutes, transfer to a twin-screw extruder for extrusion, tablet, and crush to 10μm to obtain a powder coating.

[0031] Comparative Example 1 Mix 60 parts of terminal carboxyl polyester resin, 9 parts of quartz powder, 1 part of leveling agent and 2 parts of benzoin at 350 r / min and stir for 30 minutes, then add 1 part of quartz powder and continue stirring for 15 minutes. Finally, add 5 parts of curing agent, 1 part of curing accelerator and 10 parts of catalyst and mix at 700 r / min and stir for 5 minutes. Then transfer to a twin-screw extruder for extrusion, tableting and crushing to 10 μm to obtain a powder coating.

[0032] The powder coatings obtained in Examples 1 to 8 and Comparative Example 1 were sprayed on the surface of the wooden board by an electrostatic spraying process and cured to prepare a coating with a thickness of 200 μm. The wear resistance was tested with reference to the method in GB / T 1768-2006, and the hardness was tested with reference to the method in GB / T6739-2022. The test results are recorded in Table 1.

[0033] Table 1 Wear resistance and hardness of powder coatings

[0034] It can be seen from Table 1 that the mass loss (750 g, 500 revolutions) of the powder coating provided by the present invention is less than 0.032 g, the hardness is above 4H, and it has high hardness and good wear resistance.

[0035] Compared with Comparative Example 1, the filler in Example 1 includes a vinyl silane-modified filler and a hydroxyl compound-modified filler. The mass loss of the powder coating obtained in Example 1 is lower than that in Comparative Example 1, and the hardness is higher than that in Comparative Example 1, indicating that the compound use of the vinyl silane-modified filler and the hydroxyl compound-modified filler improves the wear resistance and hardness of the powder coating.

[0036] The mass loss of the powder coatings obtained in Examples 3 to 6 is lower than that in Example 1, indicating that when the mass of the filler modified by 3 times the vinyl silane is ≤ 7 times the mass of the filler modified by the hydroxyl compound, the wear resistance of the powder coating is further improved.

[0037] The mass loss of the powder coatings obtained in Examples 4 to 5 is lower than that in Examples 3 and 6, and the hardness is higher than that in Examples 3 and 6, indicating that the mass ratio of the vinyl silane modified filler to the hydroxyl compound modified filler is 1:1 to 3:7, which further improves the wear resistance and hardness of the powder coatings.

[0038] The mass loss of the powder coating obtained in Example 5 is lower than that in Example 7 and Example 8, indicating that the addition of the vinyl silane-modified filler and then the hydroxyl compound-modified filler during the preparation process further improves the wear resistance of the powder coating.

[0039] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A powder coating for non-metallic coating, characterized in that: The invention comprises the following components in parts by weight: 60-70 parts of terminal carboxyl polyester resin, 5-8 parts of curing agent, 1-3 parts of curing accelerator, 10-20 parts of modified filler, 1-3 parts of leveling agent, 2-3 parts of benzoin and 10-15 parts of catalyst. The modified filler comprises a vinyl silane modified filler and a hydroxy compound modified filler in a mass ratio of 1:9-9:

1.

2. A powder coating for non-metallic coating according to claim 1, characterized in that: The mass of the filler modified with vinyl silane is 3 times less than or equal to 7 times the mass of the filler modified with hydroxyl compound.

3. A powder coating for non-metallic coating according to claim 2, characterized in that: The mass ratio of the vinyl silane modified filler to the hydroxy compound modified filler is 1:1 to 3:

7.

4. The powder coating for non-metallic coating according to claim 1, characterized in that: The raw materials of the vinyl silane modified filler include vinyl silane and filler in a mass ratio of 0.5 to 1:

10.

5. The powder coating for non-metallic coating according to claim 1, characterized in that: The raw material containing the hydroxy compound modified filler comprises a hydroxy compound and a filler in a mass ratio of 0.5 to 1.5:

20.

6. The powder coating for non-metallic coating according to claim 4, characterized in that: The preparation method of the vinyl silane modified filler comprises the following steps: dispersing the filler evenly in water, adding vinyl silane to continue dispersing, filtering, and drying to obtain the vinyl silane modified filler.

7. The powder coating for non-metallic coating according to claim 5, characterized in that: The preparation method of the modified filler containing hydroxyl compounds comprises the following steps: uniformly mixing the hydroxyl compound with a solvent, adding a filler and continuing to mix, filtering, and drying to obtain the modified filler containing hydroxyl compounds.

8. A powder coating for non-metallic coating according to claim 4 or 5, characterized in that: The fillers each independently include one or both of quartz powder and talc powder.

9. The powder coating for non-metallic coating according to claim 1, characterized in that: The catalyst comprises one or both of methyl triphenyl phosphonium bromide and butyl triphenyl phosphonium chloride.

10. The method for preparing a powder coating for non-metallic coating according to any one of claims 1 to 9, characterized in that: The method comprises the following steps: uniformly mixing carboxyl-terminated polyester resin, vinyl silane modified filler, leveling agent and benzoin, adding hydroxyl compound modified filler and continuing to mix, and finally adding curing agent, curing accelerator and catalyst and mixing, extruding, tabletting and crushing to obtain powder coating.

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