A graphene flame-retardant powder coating and a preparation method thereof

Abstract

The application relates to the technical field of powder coating preparation, and particularly discloses graphene flame-retardant powder coating and a preparation method thereof. The graphene flame-retardant powder coating and the preparation method thereof contain the following components in parts by weight: 30-50 parts of epoxy resin; 30-50 parts of polyester resin; 20-40 parts of barium sulfate; 10-20 parts of flame retardant; 1-3 parts of dispersant; 0.5-2 parts of curing agent; and 1-3 parts of leveling agent; wherein the flame retardant is composed of graphene and yttrium oxide. The graphene flame-retardant powder coating has good flame-retardant effect and good impact resistance.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of powder coating preparation, and in particular to a graphene flame-retardant powder coating and a preparation method thereof. BACKGROUND

[0002] The powder coating is solid powder synthetic resin coating composed of solid resin, fillers and additives. It is different from ordinary solvent-based coating and water-based coating, and its dispersion medium is not solvent and water but air; thus, it has no solvent pollution. With the increasing environmental protection requirements in various industries, the demand for powder coating is increasing.

[0003] Chinese Invention Patent 202010114060.1 discloses a flame-retardant powder coating and a preparation method thereof. The flame-retardant powder coating comprises the following components in parts by weight: epoxy resin 28-32 parts, polyester resin 28-32 parts, pigment 5-10 parts, barium sulfate 30-40 parts, titanium dioxide 0.5-5 parts, flame retardant 2-8 parts, flame retardant additive 0.1-0.5 parts, leveling agent 0.5-2 parts, bentonite 0.5-1 part, and curing accelerator 0.01-0.05 part. The application uses graphene and benzimidazole carboxylic acid metal complex as a flame retardant, and has good flame-retardant effect. However, the inventors have found in research that the flame-retardant powder coating has good flame-retardant effect, but its impact resistance needs to be further improved. SUMMARY

[0004] In order to overcome at least one of the technical problems in the prior art, the application provides a graphene flame-retardant powder coating.

[0005] The technical solution of the application is as follows:

[0006] The application provides a graphene flame-retardant powder coating and a preparation method thereof, which comprises the following components in parts by weight:

[0007] Epoxy resin 30-50 parts, polyester resin 30-50 parts, barium sulfate 20-40 parts, flame retardant 10-20 parts, dispersant 1-3 parts, curing agent 0.5-2 parts, and leveling agent 1-3 parts.

[0008] The flame retardant is composed of graphene and yttrium oxide.

[0009] The application adds a flame retardant composed of graphene and yttrium oxide, which not only makes the graphene flame-retardant powder coating have good flame-retardant effect, but also makes the graphene flame-retardant powder coating have good impact resistance.

[0010] Preferably, the graphene flame-retardant powder coating and the preparation method thereof comprise the following components in parts by weight:

[0011] Epoxy resin 40-50 parts; polyester resin 30-40 parts; barium sulfate 20-30 parts; flame retardant 10-15 parts; dispersant 1-2 parts; curing agent 0.1-0.5 parts; leveling agent 1-2 parts.

[0012] Preferably, the graphene flame-retardant powder coating and the preparation method thereof comprise the following components by weight:

[0013] Epoxy resin 40 parts; polyester resin 30 parts; barium sulfate 30 parts; flame retardant 15 parts; dispersant 2 parts; curing agent 1 part; leveling agent 2 parts.

[0014] Preferably, the weight ratio of graphene and yttrium oxide in the flame retardant is 3-5:2-4.

[0015] Most preferably, the weight ratio of graphene and yttrium oxide in the flame retardant is 4:3.

[0016] Preferably, the flame retardant is a modified flame retardant.

[0017] The modified flame retardant is prepared by the following method:

[0018] (1) Mix graphene and yttrium oxide, then add to water and mix uniformly, then add phosphoric acid, stir for 2-3 h, separate the solid, dry the solid to obtain the mixture;

[0019] (2) Add the mixture to an ethanol aqueous solution, heat to 60-80℃, then add a modifier, continue to stir at 60-80℃ for 2-3 h, separate the solid, dry the solid to obtain the modified flame retardant.

[0020] The inventors surprisingly found that, in the graphene flame-retardant powder coating, adding the modified flame retardant prepared by modifying graphene and yttrium oxide by the above method can further greatly improve the impact resistance of the graphene flame-retardant powder coating compared to adding the unmodified flame retardant composed only of graphene and yttrium oxide.

[0021] Preferably, the total weight of graphene and yttrium oxide in step (1) is 1 kg, and the amount of phosphoric acid and water is 1-2 L and 7-10 L, respectively.

[0022] Most preferably, the total weight of graphene and yttrium oxide in step (1) is 1 kg, and the amount of phosphoric acid and water is 1.5 L and 8.5 L, respectively.

[0023] Preferably, the phosphoric acid in step (1) refers to a phosphoric acid aqueous solution with a mass fraction of 50-60%.

[0024] Most preferably, the phosphoric acid in step (1) refers to a 55% mass fraction phosphoric acid aqueous solution.

[0025] Preferably, the mixture in step (2) is mixed with the modifier and the ethanol aqueous solution in a ratio of 3-5 kg: 2-4 kg: 20-30 L.

[0026] Most preferably, the mixture in step (2) is mixed with the modifier and the ethanol aqueous solution in a ratio of 4 kg: 3 kg: 25 L.

[0027] Preferably, the modifier in step (2) is composed of tridecafluorooctyltrimethoxysilane and nonylphenol polyoxyethylene ether.

[0028] The inventors surprisingly found in the research that in the preparation process of the modified flame retardant of the application, the selection of the modifier is very critical, and the modified flame retardant prepared by modifying graphene and yttrium oxide with the modifier composed of tridecafluorooctyltrimethoxysilane and nonylphenol polyoxyethylene ether can further greatly improve the impact resistance of graphene flame-retardant powder coating compared with the unmodified flame retardant composed of graphene and yttrium oxide; however, the modified flame retardant prepared by modifying graphene and yttrium oxide with single tridecafluorooctyltrimethoxysilane or nonylphenol polyoxyethylene ether or other combinations of modifiers cannot further greatly improve the impact resistance of graphene flame-retardant powder coating.

[0029] Preferably, the weight ratio of tridecafluorooctyltrimethoxysilane to nonylphenol polyoxyethylene ether in the modifier is 1-3: 1-3.

[0030] Most preferably, the weight ratio of tridecafluorooctyltrimethoxysilane to nonylphenol polyoxyethylene ether in the modifier is 1: 1.

[0031] Preferably, the ethanol aqueous solution in step (2) refers to an ethanol aqueous solution with a volume fraction of 95%.

[0032] The application also provides a preparation method of the graphene flame-retardant powder coating, which comprises the following steps: uniformly mixing epoxy resin, polyester resin, barium sulfate, flame retardant, dispersant, curing agent and leveling agent, then extruding and tabletting by a double-screw extruder, crushing, and then grinding by a powder grinder to obtain the wear-resistant powder coating.

[0033] Beneficial effects: the application provides a graphene flame-retardant powder coating with a completely new composition; the graphene flame-retardant powder coating has not only good flame-retardant effect, but also good impact resistance. DETAILED DESCRIPTION

[0034] The application is further explained below in connection with specific embodiments, which do not limit the application in any form.

[0035] In the following examples, the polyester resin is a polyester resin with a trade name of 9005-6-73 produced by Shandong Kaipu Le; the epoxy resin is a bisphenol A solid epoxy resin with a trade name of CYD-011 (E-20) produced by Balin Petrochemical; the remaining raw materials not marked with sources are conventional raw materials that can be purchased by conventional purchase channels by those skilled in the art; the above raw material sources of the application do not limit the protection scope of the application.

[0036] Example 1 Preparation of graphene flame-retardant powder coating

[0037] Raw material weight parts composition: epoxy resin 40 parts; polyester resin 30 parts; barium sulfate 30 parts; flame retardant 15 parts; dispersant (ethylene bis stearamide) 2 parts; curing agent (adipic acid dihydrazide) 1 part; leveling agent (leveling agent PV88) 2 parts;

[0038] The flame retardant is composed of graphene and yttrium oxide in a weight ratio of 4:3.

[0039] Preparation method: after the above raw materials are uniformly mixed, they are extruded by a double-screw extruder, tabletted and broken, and then ground by a powder mill to obtain the graphene flame-retardant powder coating.

[0040] Example 2 Preparation of graphene flame-retardant powder coating

[0041] Raw material weight parts composition: epoxy resin 40 parts; polyester resin 30 parts; barium sulfate 30 parts; flame retardant 15 parts; dispersant (ethylene bis stearamide) 2 parts; curing agent (adipic acid dihydrazide) 1 part; leveling agent (leveling agent PV88) 2 parts;

[0042] The flame retardant is a modified flame retardant, which is prepared by the following method:

[0043] (1) After graphene and yttrium oxide are mixed and added to water, they are uniformly mixed, and then phosphoric acid is added. After stirring for 2 h, the solid is separated, and the solid is dried to obtain a mixture; wherein the weight ratio of graphene and yttrium oxide is 4:3; the total weight of graphene and yttrium oxide to the amount of phosphoric acid and water is 1 kg: 1.5 L: 8.5 L; the phosphoric acid refers to a 55% mass fraction phosphoric acid aqueous solution;

[0044] (2) the mixture is added to an ethanol aqueous solution, heated to 70°C, then a modifier is added, and stirring is continued at 70°C for 2h, then the solid is separated, dried, and the modified flame retardant is obtained; wherein the use amount ratio of the mixture, the modifier, and the ethanol aqueous solution is 4kg:3kg:25L; the modifier is composed of tridecafluorooctyltrimethoxysilane and nonylphenol polyoxyethylene ether NP-10 at a weight ratio of 1:1; the ethanol aqueous solution refers to an ethanol aqueous solution with a volume fraction of 95%.

[0045] Preparation method: the raw materials are uniformly mixed, then extruded through a double-screw extruder, tabletted and broken, then ground through a powder grinder, and the graphene flame-retardant powder coating is obtained.

[0046] Preparation of the graphene flame-retardant powder coating in Comparative Example 1

[0047] The raw material weight portion composition and the preparation method are the same as in Example 2; the difference between Comparative Example 1 and Example 2 is the preparation method of the modified flame retardant.

[0048] The modified flame retardant in Comparative Example 1 is prepared by the following method:

[0049] (1) graphene and yttria are mixed and added to water, then phosphoric acid is added, stirring is continued for 2h, then the solid is separated, dried, and the mixture is obtained; wherein the weight ratio of graphene and yttria is 4:3; the total weight of graphene and yttria and the use amount of phosphoric acid and water is 1kg:1.5L:8.5L; the phosphoric acid refers to a phosphoric acid aqueous solution with a mass fraction of 55%;

[0050] (2) the mixture is added to an ethanol aqueous solution, heated to 70°C, then a modifier is added, and stirring is continued at 70°C for 2h, then the solid is separated, dried, and the modified flame retardant is obtained; wherein the use amount ratio of the mixture, the modifier, and the ethanol aqueous solution is 4kg:3kg:25L; the modifier is tridecafluorooctyltrimethoxysilane; the ethanol aqueous solution refers to an ethanol aqueous solution with a volume fraction of 95%.

[0051] Preparation of the graphene flame-retardant powder coating in Comparative Example 2

[0052] The raw material weight portion composition and the preparation method are the same as in Example 2; the difference between Comparative Example 1 and Example 2 is the preparation method of the modified flame retardant.

[0053] The modified flame retardant in Comparative Example 1 is prepared by the following method:

[0054] (1)mixing graphene and yttria, then adding into water, mixing uniformly, then adding phosphoric acid, separating solid after stirring for 2h, drying the solid to obtain the mixture; wherein the weight ratio of graphene and yttria is 4:3; the total weight of graphene and yttria to the amount of phosphoric acid and water is 1kg:1.5L:8.5L; the phosphoric acid refers to a phosphoric acid aqueous solution with a mass fraction of 55%;

[0055] (2)adding the mixture into an ethanol aqueous solution, heating to 70℃, then adding a modifier, continuing to stir at 70℃ for 2h, then separating the solid, drying the solid to obtain the modified flame retardant; wherein the amount ratio of the mixture, the modifier and the ethanol aqueous solution is 4kg:3kg:25L; the modifier is nonylphenol polyoxyethylene ether NP-10; the ethanol aqueous solution refers to an ethanol aqueous solution with a volume fraction of 95%.

[0056] Preparation of graphene flame-retardant powder coating

[0057] Raw material weight parts composition: epoxy resin 40 parts; polyester resin 30 parts; barium sulfate 30 parts; flame retardant 15 parts; dispersing agent (ethylene bis stearyl amide) 2 parts; curing agent (adipic acid dihydrazide) 1 part; leveling agent (leveling agent PV88) 2 parts;

[0058] The flame retardant is a modified flame retardant, and the modified flame retardant is prepared by the following method:

[0059] (1)mixing graphene and yttria, then adding into water, mixing uniformly, then adding phosphoric acid, separating solid after stirring for 2h, drying the solid to obtain the mixture; wherein the weight ratio of graphene and yttria is 4:3; the total weight of graphene and yttria to the amount of phosphoric acid and water is 1kg:1.5L:8.5L; the phosphoric acid refers to a phosphoric acid aqueous solution with a mass fraction of 55%;

[0060] (2)adding the mixture into an ethanol aqueous solution, heating to 70℃, then adding a modifier, continuing to stir at 70℃ for 2h, then separating the solid, drying the solid to obtain the modified flame retardant; wherein the amount ratio of the mixture, the modifier and the ethanol aqueous solution is 4kg:3kg:25L; the modifier is composed of tridecafluorooctyltrimethoxysilane and sodium dodecylbenzenesulfonate with a weight ratio of 1:1; the ethanol aqueous solution refers to an ethanol aqueous solution with a volume fraction of 95%.

[0061] Preparation method: mixing the above raw materials uniformly, then extruding through a double screw extruder, tabletting and crushing, then grinding through a powder mill to obtain the graphene flame-retardant powder coating.

[0062] The graphene flame-retardant powder coatings prepared from Examples 1-2 and Comparative Examples 1-3 were tested for their flame-retardant grades according to the method in the UL94 standard, and their impact resistance was tested according to the method in GB T 1732-2020, and the test results are shown in Table 1.

[0063] Table 1. Test results of the performance of the graphene flame-retardant powder coatings

[0064] Flame retardant class Impact resistance Graphene flame retardant powder coating prepared from example 1 V0 42 cm Graphene flame retardant powder coating prepared from example 2 V0 58 cm Graphene flame retardant powder coating prepared from comparative example 1 V0 44 cm Graphene flame retardant powder coating prepared from comparative example 2 V0 45 cm Graphene flame retardant powder coating prepared from comparative example 3 V0 47 cm

[0065] As can be seen from the experimental data in Table 1, the graphene flame-retardant powder coatings prepared from Examples 1 and 2 have a flame-retardant grade of V0, which shows that the graphene flame-retardant powder coatings according to the present application have good flame-retardant effect.

[0066] As can be seen from the experimental data in Table 1, the graphene flame-retardant powder coating prepared from Example 1 has an impact resistance of 42 cm, which shows that the graphene flame-retardant powder coating according to the present application also has good impact resistance.

[0067] As can be seen from the experimental data in Table 1, the graphene flame-retardant powder coating prepared from Example 2 has further significantly higher impact resistance than the graphene flame-retardant powder coating prepared from Example 1, which shows that, compared with adding the unmodified flame-retardant agent composed of only graphene and yttrium oxide, adding the modified flame-retardant agent prepared by modifying graphene and yttrium oxide according to the method of the present application can further significantly improve the impact resistance of the graphene flame-retardant powder coating.

[0068] As can be seen from the experimental data in Table 1, the graphene flame-retardant powder coatings prepared from Comparative Examples 1-3 have improved impact resistance compared with the graphene flame-retardant powder coating prepared from Example 1, but the improvement is not large, and the improvement is much smaller than that of the graphene flame-retardant powder coating prepared from Example 2, which shows that, in the preparation of the modified flame-retardant agent according to the present application, the selection of the modifier is very critical, and the modified flame-retardant agent prepared by modifying graphene and yttrium oxide with the modifier composed of tridecafluorooctyltrimethoxysilane and nonylphenol polyoxyethylene ether can further significantly improve the impact resistance of the graphene flame-retardant powder coating compared with adding only the unmodified flame-retardant agent composed of graphene and yttrium oxide, while the modified flame-retardant agent prepared by modifying graphene and yttrium oxide with a single tridecafluorooctyltrimethoxysilane or nonylphenol polyoxyethylene ether or other combinations of modifiers cannot further significantly improve the impact resistance of the graphene flame-retardant powder coating.

Claims

1. A graphene flame-retardant powder coating, characterized in that, It contains the following components in parts by weight: Epoxy resin 30-50 parts; polyester resin 30-50 parts; barium sulfate 20-40 parts; flame retardant 10-20 parts; dispersant 1-3 parts; curing agent 0.5-2 parts; leveling agent 1-3 parts; The flame retardant is a modified flame retardant; the modified flame retardant is prepared by the following method: (1) After mixing graphene and yttrium oxide, add them to water and mix evenly. Then add phosphoric acid, stir for 2-3 hours, separate the solid, and dry the solid to obtain the mixture. The weight ratio of graphene to yttrium oxide is 3-5:2-4. (2) Add the mixture to an ethanol aqueous solution, heat to 60~80℃, then add the modifier, continue stirring at 60~80℃ for 2~3h, then separate the solid, and dry the solid to obtain the modified flame retardant. The modifier mentioned in step (2) is composed of tridecafluorooctyltrimethoxysilane and nonylphenol polyoxyethylene ether; the weight ratio of tridecafluorooctyltrimethoxysilane to nonylphenol polyoxyethylene ether in the modifier is 1~3:1~3.

2. The graphene flame-retardant powder coating according to claim 1, characterized in that, It contains the following components in parts by weight: 40-50 parts epoxy resin; 30-40 parts polyester resin; 20-30 parts barium sulfate; 10-15 parts flame retardant; 1-2 parts dispersant; 0.1-0.5 parts curing agent; 1-2 parts leveling agent.

3. The graphene flame-retardant powder coating according to claim 1, characterized in that, It contains the following components in parts by weight: 40 parts epoxy resin; 30 parts polyester resin; 30 parts barium sulfate; 15 parts flame retardant; 2 parts dispersant; 1 part curing agent; 2 parts leveling agent.

4. The graphene flame-retardant powder coating according to claim 1, characterized in that, The weight ratio of graphene to yttrium oxide is 4:

3.

5. The graphene flame-retardant powder coating according to claim 1, characterized in that, In step (1), the ratio of the total weight of graphene and yttrium oxide to the amount of phosphoric acid and water is 1 kg: 1~2 L: 7~10 L.

6. The graphene flame-retardant powder coating according to claim 1, characterized in that, The phosphoric acid mentioned in step (1) refers to an aqueous solution of phosphoric acid with a mass fraction of 50-60%.

7. The graphene flame-retardant powder coating according to claim 1, characterized in that, In step (2), the ratio of the mixture to the modifier and the ethanol aqueous solution is 3~5kg:2~4kg:20~30L.

8. The method for preparing the graphene flame-retardant powder coating according to any one of claims 1 to 7, characterized in that, It includes the following steps: The graphene flame-retardant powder coating is obtained by uniformly mixing epoxy resin, polyester resin, barium sulfate, flame retardant, dispersant, curing agent and leveling agent, extruding through a twin-screw extruder, pressing and crushing, and then pulverizing through a grinding mill.