A fire-resistant powder coating, its preparation method and application

Abstract

The present invention relates to a fire-resistant powder coating, a preparation method thereof and an application. The fire-resistant powder coating comprises the following raw materials in parts by mass: 100 parts of phenolic epoxy resin; 20-30 parts of aromatic triamine; 10-20 parts of amino-terminated polydimethylsiloxane; 10-20 parts of polyphenylmethylsiloxane; 10-15 parts of pentaerythritol glycidyl ether; 5-10 parts of hexaphenoxycyclotriphosphazene; 60-80 parts of inorganic filler. The fire-resistant powder coating can withstand an open flame for a long time.

Description

Technical Field

[0001] The present invention relates to the technical field of coatings, and particularly relates to a fire-resistant powder coating, a preparation method thereof, and an application thereof. Background Art

[0002] Powder coatings are coatings in the form of fine powders. Since they do not use solvents, they have advantages such as environmental protection, safety, and high efficiency. Among them, thermosetting powder coatings are powder coatings prepared using thermosetting resins. After the thermosetting powder coating is applied to an object, the coating reacts and cures through heating and other means, and a crosslinked resin film can be obtained, which is the cured coating. The coating formed by the thermosetting powder coating usually can withstand a relatively high temperature due to its crosslinked structure.

[0003] Fire-resistant coatings are coatings with fire-resistant capabilities and can be used in fields such as stoves, flues, cooking utensils, heaters, etc. Thermosetting powder coatings have good application prospects in fire-resistant coatings. However, some current powder coatings are prone to cracking and damage when exposed to an open flame for a long time. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the first object of the present invention is to provide a fire-resistant powder coating that can withstand an open flame for a long time.

[0005] The second object of the present invention is to provide a preparation method for the fire-resistant powder coating, and this preparation method has advantages such as simple steps.

[0006] The third object of the present invention is to provide an application of the fire-resistant powder coating.

[0007] To achieve the first object of the present invention, the present invention provides a fire-resistant powder coating, which comprises the following raw materials in parts by mass: 100 parts of phenolic epoxy resin; 20 - 30 parts of aromatic triamine; 10 - 20 parts of amino-terminated polydimethylsiloxane; 10 - 20 parts of polyphenylmethylsiloxane; 10 - 15 parts of pentaerythritol glycidyl ether; 5 - 10 parts of hexaphenoxycyclotriphosphazene; 60 - 80 parts of inorganic filler.

[0008] In some embodiments of the present invention, the fire-resistant powder coating comprises the following raw materials in parts by mass: 100 parts of phenolic epoxy resin; 25 - 30 parts of aromatic triamine; 10 - 15 parts of amino-terminated polydimethylsiloxane; 15 - 20 parts of polyphenylmethylsiloxane; 10 - 12 parts of pentaerythritol glycidyl ether; 8 - 10 parts of hexaphenoxycyclotriphosphazene; 70 - 80 parts of inorganic filler.

[0009] In some embodiments of the present invention, the inorganic filler comprises at least one of flaky alumina, ceramic powder, and silicon dioxide.

[0010] In some embodiments of the present invention, the particle size of the flaky alumina is 3 - 15 μm, the particle size of the ceramic powder is 1 - 20 μm, and the particle size of the silicon dioxide is 1 - 50 μm.

[0011] In some embodiments of the present invention, the inorganic filler is a mixture of at least one of flaky alumina, ceramic powder, and silicon dioxide, and the mass content of the flaky alumina in the inorganic filler is 20 - 30%.

[0012] In some embodiments of the present invention, the weight - average molecular weight of the amino - terminated polydimethylsiloxane is 1000 - 1500.

[0013] In some embodiments of the present invention, the weight - average molecular weight of the polyphenylmethylsiloxane is 2500 - 3000.

[0014] In some embodiments of the present invention, the phenolic epoxy resin is at least one of NPCN - 702 and NPCN - 704.

[0015] In some embodiments of the present invention, the aromatic triamine is at least one of benzene - 1,3,5 - triamine, 1,3,5 - tris(4 - aminophenyl)benzene, and N,N',N'' - triphenylbenzene - 1,3,5 - triamine.

[0016] To achieve the second object of the present invention, the present invention provides a method for preparing the fire - resistant powder coating according to any of the above - mentioned schemes, which includes the following steps: Step 1: Heat and mix the amino - terminated polydimethylsiloxane, polyphenylmethylsiloxane, and pentaerythritol glycidyl ether evenly at a first temperature to obtain a first mixture; Step 2: Heat and mix the first mixture, phenolic epoxy resin, aromatic triamine, hexaphenoxycyclotriphosphazene, and inorganic filler evenly at a second temperature, and then pulverize after cooling to obtain the fire - resistant powder coating.

[0017] In some embodiments of the present invention, in Step 1, the first temperature is 120 - 130 °C, and the time for heating and mixing evenly at the first temperature is 10 - 20 min.

[0018] In some embodiments of the present invention, in Step 2, the second temperature is 90 - 100 °C, and the time for heating and mixing evenly at the second temperature is 5 - 10 min.

[0019] In some embodiments of the present invention, Step 2 is carried out in a twin - screw extruder.

[0020] To achieve the third object of the present invention, the present invention provides a coating which is formed by heating and curing the fire - resistant powder coating according to any of the above - mentioned schemes.

[0021] Compared with the prior art, the present invention can achieve the following beneficial effects:

[0022] The fire-resistant powder coating of the present invention uses phenolic epoxy resin and aromatic triamine to form an epoxy resin system. This epoxy resin has a high cross-linking degree and good high-temperature resistance. The present invention also uses amino-terminated polydimethylsiloxane and polyphenylmethylsiloxane to provide polysiloxane segments, improving the high-temperature resistance of the resin. Moreover, in combination with pentaerythritol glycidyl ether, hexaphenoxycyclotriphosphazene, etc., it improves the high-temperature resistance and flame retardancy of the resin system. The fire-resistant powder coating of the present invention also adds a relatively large amount of high-temperature resistant and flame-retardant inorganic fillers to improve the high-temperature resistance and flame retardancy of the coating. With the mutual cooperation of the above-mentioned various components, the fire-resistant powder coating of the present invention obtains a coating that can withstand an open flame for a long time. Detailed implementation mode

[0023] An embodiment of the present invention provides a fire-resistant powder coating. This fire-resistant powder coating can withstand an open flame for a long time and maintain the adhesion and mechanical strength of the coating under the action of an open flame for a long time. This fire-resistant powder coating can be used for stoves, flues, cooking utensils, heaters, and can also be used in other application scenarios with high temperature and open flame.

[0024] Specifically, the fire-resistant powder coating includes the following raw materials in parts by mass: 100 parts of phenolic epoxy resin; 20 - 30 parts of aromatic triamine; 10 - 20 parts of amino-terminated polydimethylsiloxane; 10 - 20 parts of polyphenylmethylsiloxane; 10 - 15 parts of pentaerythritol glycidyl ether; 5 - 10 parts of hexaphenoxycyclotriphosphazene; 60 - 80 parts of inorganic filler.

[0025] Among them, the phenolic epoxy resin can be at least one of phenol phenolic epoxy resin, o-cresol novolac epoxy resin, bisphenol A phenolic epoxy resin, etc. The phenolic epoxy resin contains a large number of phenyl groups and epoxy groups. The phenyl group can improve the mechanical properties and high-temperature resistance of the resin, and the epoxy group can react with the amino group to obtain a resin system with a high degree of crosslinking. The aromatic triamine contains a phenyl group and an amino group. The phenyl group can improve the mechanical properties and high-temperature resistance of the resin, and the amino group, as the curing group of the epoxy group, can increase the crosslinking degree of the resin. The amino-terminated polydimethylsiloxane introduces a silicone-oxygen chain with high-temperature resistance and good flame retardancy into the resin system. The amino-terminated group can react with the epoxy group to introduce polydimethylsiloxane into the resin system, so that the polysiloxane is evenly dispersed and tightly combined in the resin system. The polyphenylmethylsiloxane molecular chain contains a phenyl group and a polysiloxane segment, which can improve the high-temperature resistance and flame retardancy of the system, and the polyphenylmethylsiloxane and the amino-terminated polydimethylsiloxane have good compatibility. The polyphenylmethylsiloxane can be evenly dispersed into the resin system together with the amino-terminated polydimethylsiloxane. Pentaerythritol glycidyl ether is a polyepoxy compound, which can adjust the crosslinking degree and compactness of the resin system, thereby improving the high-temperature resistance and flame retardancy of the resin system. Hexaphenoxycyclotriphosphazene contains a large number of phenyl groups and phosphorus-nitrogen rings, and can also improve the high-temperature resistance and flame retardancy of the resin system. The resin system also contains a large amount of inorganic fillers to further improve the high-temperature resistance and flame retardancy. The raw materials of the above-mentioned various components are mutually coordinated in a specific dosage ratio, which can improve the long-term fire resistance performance of the coating formed by the fire-resistant powder coating, so that the coating maintains good adhesion and mechanical properties under long-term open fire.

[0026] In some examples of this embodiment, relative to 100 parts by mass of the phenolic epoxy resin, the parts by mass of the aromatic triamine can be 20 parts, 21 parts, 22 parts, 23 parts, 24 parts, 25 parts, 26 parts, 27 parts, 28 parts, 29 parts, 30 parts, etc.; the parts by mass of the amino-terminated polydimethylsiloxane can be 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, 18 parts, 19 parts, 20 parts, etc.; the parts by mass of the polyphenylmethylsiloxane can be 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, 18 parts, 19 parts, 20 parts, etc.; the parts by mass of pentaerythritol glycidyl ether are 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, etc.; the parts by mass of hexaphenoxycyclotriphosphazene can be 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, etc.; the parts by mass of the inorganic filler can be 60 parts, 61 parts, 62 parts, 63 parts, 64 parts, 65 parts, 66 parts, 67 parts, 68 parts, 69 parts, 70 parts, 71 parts, 72 parts, 73 parts, 74 parts, 75 parts, 76 parts, 77 parts, 78 parts, 79 parts, 80 parts, etc.

[0027] In some examples of this embodiment, the fire-resistant powder coating mainly consists of the following raw materials in parts by mass: 100 parts of phenolic epoxy resin; 20 - 30 parts of aromatic triamine; 10 - 20 parts of amino-terminated polydimethylsiloxane; 10 - 20 parts of polyphenylmethylsiloxane; 10 - 15 parts of pentaerythritol glycidyl ether; 5 - 10 parts of hexaphenoxycyclotriphosphazene; 60 - 80 parts of inorganic filler. In addition to phenolic epoxy resin, aromatic triamine, amino-terminated polydimethylsiloxane, polyphenylmethylsiloxane, pentaerythritol glycidyl ether, hexaphenoxycyclotriphosphazene, and inorganic filler, the fire-resistant powder coating may also contain a small amount of, for example, 1 - 10 parts by mass of additives, and may also include pigments.

[0028] In some examples of this embodiment, the fire-resistant powder coating consists of the following raw materials in parts by mass: 100 parts of phenolic epoxy resin; 20 - 30 parts of aromatic triamine; 10 - 20 parts of amino-terminated polydimethylsiloxane; 10 - 20 parts of polyphenylmethylsiloxane; 10 - 15 parts of pentaerythritol glycidyl ether; 5 - 10 parts of hexaphenoxycyclotriphosphazene; 60 - 80 parts of inorganic filler. Except for phenolic epoxy resin, aromatic triamine, amino-terminated polydimethylsiloxane, polyphenylmethylsiloxane, pentaerythritol glycidyl ether, hexaphenoxycyclotriphosphazene, and inorganic filler, the fire-resistant powder coating does not contain other raw materials, and its composition is simpler.

[0029] In some examples of this embodiment, the fire-resistant powder coating includes the following raw materials in parts by mass: 100 parts of phenolic epoxy resin; 25 - 30 parts of aromatic triamine; 10 - 15 parts of amino-terminated polydimethylsiloxane; 15 - 20 parts of polyphenylmethylsiloxane; 12 - 15 parts of pentaerythritol glycidyl ether; 8 - 10 parts of hexaphenoxycyclotriphosphazene; 70 - 80 parts of inorganic filler. When the dosages of each component are within the above ranges, the resulting coating has better fire resistance.

[0030] In some examples of this embodiment, the inorganic filler includes at least one of flaky alumina, ceramic powder, and silica. The above inorganic filler raw materials are easily available, have high temperature resistance and fire resistance, and can improve the high temperature resistance and fire resistance of the coating.

[0031] In some examples of this embodiment, the particle size of the flaky alumina is 3 - 15 μm, the particle size of the ceramic powder is 1 - 20 μm, and the particle size of the silica is 1 - 50 μm. When the particle sizes of the above fillers are within the above ranges, the fillers are evenly dispersed in the resin system, and have good temperature resistance and flame retardancy. The particle size of the flaky alumina refers to the average diameter of its flaky plane.

[0032] In some examples of this embodiment, the inorganic filler is a mixture of at least one of flaky alumina, ceramic powder, and silica. The mass content of flaky alumina in the inorganic filler is 20% to 30%, that is, the mass of flaky alumina accounts for 20% to 30% of the total mass of the inorganic filler. The use of flaky fillers in combination with ordinary spherical or quasi-spherical fillers helps to further improve the fire resistance of the coating.

[0033] In some examples of this embodiment, the weight-average molecular weight of the amino-terminated polydimethylsiloxane is 1000 to 1500, and the weight-average molecular weight of the polyphenylmethylsiloxane is 2500 to 3000. When the molecular weight of the polysiloxane raw material is within the above range, the coating has good fire resistance and the raw materials are easy to disperse.

[0034] In some examples of this embodiment, the phenolic epoxy resin is at least one of NPCN-702 and NPCN-704. The above phenolic epoxy resin comes from Kunshan Nan Ya, has a high epoxy group content, and helps to maintain the particle morphology of the powder coating and improve the storage stability.

[0035] In some examples of this embodiment, the aromatic triamine is at least one of melamine, 1,3,5-tris(4-aminophenyl)benzene, and N,N',N''-triphenyl-1,3,5-benzenetriamine. The above triamine contains three amino groups in one molecule, which is beneficial to increasing the crosslinking density of the resin system.

[0036] In some examples of this embodiment, the preparation method of the above fire-resistant powder coating may include the following steps: Step 1: Heat and mix the amino-terminated polydimethylsiloxane, polyphenylmethylsiloxane, and pentaerythritol glycidyl ether evenly at a first temperature to obtain a first mixture; Step 2: Heat and mix the first mixture, phenolic epoxy resin, aromatic triamine, hexaphenoxycyclotriphosphazene, and inorganic filler evenly at a second temperature, cool and then crush to obtain the fire-resistant powder coating.

[0037] In the preparation process of the fire-resistant powder coating of this embodiment, the amino-terminated polydimethylsiloxane, polyphenylmethylsiloxane, and pentaerythritol glycidyl ether are first mixed. The amino-terminated polydimethylsiloxane and pentaerythritol glycidyl ether can be partially polycondensed to obtain a pre-polycondensation product with a relatively increased molecular weight, which is convenient for the powder coating to maintain dry granular form and is beneficial to the mixing and dispersion of the polyphenylmethylsiloxane end and the amino-terminated polydimethylsiloxane; then the obtained mixture is mixed evenly with other raw materials and granulated to obtain the required powder coating. The preparation method is simple and the production efficiency is high.

[0038] In some examples of this embodiment, in step one, the first temperature is 120 - 130 °C, and the time for heating and mixing evenly at the first temperature is 10 - 20 min, which facilitates the uniform dispersion of amino-terminated polydimethylsiloxane, polyphenylmethylsiloxane, and pentaerythritol glycidyl ether, and helps the pre-condensation of amino-terminated polydimethylsiloxane and pentaerythritol glycidyl ether.

[0039] In some examples of this embodiment, in step two, the second temperature is 90 - 100 °C, and the time for heating and mixing evenly at the second temperature is 5 - 10 min, which helps the raw materials to be evenly dispersed and avoids premature cross-linking of the resin system.

[0040] In some examples of this embodiment, step two is carried out in a twin-screw extruder, and the operation is simple.

[0041] In some examples of this embodiment, this embodiment also provides a coating prepared from the above-mentioned fire-resistant paint. This coating can maintain good adhesion and mechanical strength under long-term open fire, and can protect the coated object from being damaged by open fire. This coating can be used for stoves, flues, heaters, reactors, cooking utensils, etc.

[0042] The fire-resistant powder coating of the present invention will be further described in detail below through specific examples.

[0043] Example 1

[0044] The preparation steps of the fire-resistant powder coating in this embodiment are as follows:

[0045] Step one: 10 parts of amino-terminated polydimethylsiloxane with a weight average molecular weight of about 1000, 15 parts of polyphenylmethylsiloxane with a weight average molecular weight of about 2500, and 12 parts of pentaerythritol glycidyl ether are heated at about 120 °C for 20 min and mixed evenly to obtain a first mixture;

[0046] Step two: All of the obtained first mixture, 100 parts of phenolic epoxy resin NPCN-702, 30 parts of 1,3,5-tris(4-aminophenyl)benzene, 10 parts of hexaphenoxycyclotriphosphazene, and 80 parts of inorganic filler (a mixture of flaky alumina with a particle size of 5 - 15 μm and silica with a particle size of 5 - 20 μm, and the flaky alumina accounts for 20% of the total amount) are melt-extruded at about 100 °C, cooled and then pulverized to obtain the fire-resistant powder coating.

[0047] Example 2

[0048] The preparation steps of the fire-resistant powder coating in this embodiment are as follows:

[0049] Step 1: Heat 15 parts of amino-terminated polydimethylsiloxane with a weight-average molecular weight of about 1500, 20 parts of polyphenylmethylsiloxane with a weight-average molecular weight of about 3000, and 10 parts of pentaerythritol glycidyl ether at about 130 °C for 10 min and mix evenly to obtain a first mixture;

[0050] Step 2: Melt-extrude all of the obtained first mixture, 100 parts of phenolic epoxy resin NPCN-704, 25 parts of N,N',N''-triphenyl-1,3,5-benzenetriamine, 8 parts of hexaphenoxycyclotriphosphazene, and 70 parts of inorganic filler (a mixture of flaky alumina with a particle size of 3 - 10 μm and ceramic powder with a particle size of 10 - 40 μm, and the flaky alumina accounts for 30% of the total amount) at about 100 °C, cool and then crush to obtain a fire-resistant powder coating.

[0051] Example 3

[0052] The preparation steps of the fire-resistant powder coating in this example are as follows:

[0053] Step 1: Heat 20 parts of amino-terminated polydimethylsiloxane with a weight-average molecular weight of about 1200, 15 parts of polyphenylmethylsiloxane with a weight-average molecular weight of about 2700, and 15 parts of pentaerythritol glycidyl ether at about 130 °C for 10 min and mix evenly to obtain a first mixture;

[0054] Step 2: Melt-extrude all of the obtained first mixture, 100 parts of phenolic epoxy resin NPCN-704, 20 parts of mellamine, 5 parts of hexaphenoxycyclotriphosphazene, and 60 parts of inorganic filler (a mixture of flaky alumina with a particle size of 3 - 10 μm and silica with a particle size of 20 - 50 μm, and the flaky alumina accounts for 30% of the total amount) at about 100 °C, cool and then crush to obtain a fire-resistant powder coating.

[0055] Example 4

[0056] The preparation steps of the fire-resistant powder coating in this example are as follows:

[0057] Step 1: Heat 15 parts of amino-terminated polydimethylsiloxane with a weight-average molecular weight of about 1000, 15 parts of polyphenylmethylsiloxane with a weight-average molecular weight of about 3000, and 12 parts of pentaerythritol glycidyl ether at about 120 °C for 20 min and mix evenly to obtain a first mixture;

[0058] Step 2: Melt-extrude all of the obtained first mixture, 100 parts of phenolic epoxy resin NPCN-702, 30 parts of 1,3,5-tris(4-aminophenyl)benzene, 10 parts of hexaphenoxycyclotriphosphazene, and 80 parts of inorganic filler (flaky alumina with a particle size of 3 - 10 μm) at about 90 °C, cool and then crush to obtain a fire-resistant powder coating.

[0059] Example 5

[0060] The preparation steps of the fire-resistant powder coating in this example are as follows:

[0061] Step 1: Heat 10 parts of amino-terminated polydimethylsiloxane with a weight-average molecular weight of about 1200, 20 parts of polyphenylmethylsiloxane with a weight-average molecular weight of about 2500, and 10 parts of pentaerythritol glycidyl ether at about 120 °C for 15 min and mix evenly to obtain a first mixture;

[0062] Step 2: Mix all of the obtained first mixture, 100 parts of phenolic epoxy resin NPCN-704, 25 parts of melamine, 8 parts of hexaphenoxycyclotriphosphazene, and 70 parts of inorganic filler (a mixture of flaky alumina with a particle size of 3 - 10 μm and ceramic powder with a particle size of 10 - 40 μm, and the flaky alumina accounts for 50% of the total amount), melt and extrude at about 100 °C, cool and then pulverize to obtain the fire-resistant powder coating.

[0063] Example 6

[0064] The preparation steps of the fire-resistant powder coating in this example are as follows:

[0065] Step 1: Heat 15 parts of amino-terminated polydimethylsiloxane with a weight-average molecular weight of about 1500, 15 parts of polyphenylmethylsiloxane with a weight-average molecular weight of about 3500, and 12 parts of pentaerythritol glycidyl ether at about 130 °C for 10 min and mix evenly to obtain a first mixture;

[0066] Step 2: Mix all of the obtained first mixture, 100 parts of phenolic epoxy resin NPCN-702, 25 parts of N,N',N''-triphenyl-1,3,5-benzenetriamine, 10 parts of hexaphenoxycyclotriphosphazene, and 80 parts of inorganic filler (a mixture of flaky alumina with a particle size of 5 - 15 μm and ceramic powder with a particle size of 5 - 20 μm, and the flaky alumina accounts for 20% of the total amount), melt and extrude at about 100 °C, cool and then pulverize to obtain the fire-resistant powder coating.

[0067] Example 7

[0068] The preparation steps of the fire-resistant powder coating in this example are as follows:

[0069] 10 parts of amino-terminated polydimethylsiloxane with a weight-average molecular weight of about 1000, 15 parts of polyphenylmethylsiloxane with a weight-average molecular weight of about 2500, 12 parts of pentaerythritol glycidyl ether, 100 parts of phenolic epoxy resin NPCN-702, 30 parts of 1,3,5-tris(4-aminophenyl)benzene, 10 parts of hexaphenoxycyclotriphosphazene, and 80 parts of inorganic filler (a mixture of flaky alumina with a particle size of 5 - 15 μm and silica with a particle size of 5 - 20 μm, and the flaky alumina accounts for 20% of the total amount) are mixed evenly in a blender, then melt-extruded at about 100 °C, cooled and crushed to obtain a fire-resistant powder coating.

[0070] Comparative Example 1

[0071] The preparation steps of the powder coating in this comparative example are as follows:

[0072] 100 parts of phenolic epoxy resin NPCN-702, 30 parts of 1,3,5-tris(4-aminophenyl)benzene, 12 parts of pentaerythritol glycidyl ether, 10 parts of hexaphenoxycyclotriphosphazene, and 80 parts of inorganic filler (a mixture of flaky alumina with a particle size of 3 - 10 μm and ceramic powder with a particle size of 10 - 40 μm, and the flaky alumina accounts for 30% of the total amount) are melt-extruded at about 100 °C, cooled and crushed to obtain a powder coating.

[0073] Comparative Example 2

[0074] The preparation steps of the powder coating in this comparative example are as follows:

[0075] Step 1: 10 parts of amino-terminated polydimethylsiloxane with a weight-average molecular weight of about 1200, 10 parts of polyphenylmethylsiloxane with a weight-average molecular weight of about 2500, and 12 parts of pentaerythritol glycidyl ether are heated at about 120 °C for 20 min and mixed evenly to obtain a first mixture;

[0076] Step 2: All of the obtained first mixture, 100 parts of phenolic epoxy resin NPCN-702, 30 parts of 1,3,5-tris(4-aminophenyl)benzene, and 90 parts of inorganic filler (a mixture of flaky alumina with a particle size of 3 - 10 μm and ceramic powder with a particle size of 10 - 40 μm, and the flaky alumina accounts for 30% of the total amount) are melt-extruded at about 100 °C, cooled and crushed to obtain a powder coating.

[0077] Comparative Example 3

[0078] The preparation steps of the powder coating in this comparative example are as follows:

[0079] Step 1: Heat 10 parts of amino-terminated polydimethylsiloxane with a weight-average molecular weight of about 1000, 15 parts of polyphenylmethylsiloxane with a weight-average molecular weight of about 2500, and 12 parts of pentaerythritol glycidyl ether at about 130 °C for 10 min and mix evenly to obtain a first mixture;

[0080] Step 2: Melt and extrude all of the obtained first mixture, 100 parts of phenolic epoxy resin NPCN-702, 30 parts of m-phenylenediamine, 10 parts of hexaphenoxycyclotriphosphazene, and 80 parts of inorganic filler (a mixture of flaky alumina with a particle size of 3 - 10 μm and ceramic powder with a particle size of 10 - 40 μm, and the flaky alumina accounts for 30% of the total amount) at about 100 °C, cool and then crush to obtain a powder coating.

[0081] Coat the coatings obtained in the above examples and comparative examples on a metal substrate by electrostatic spraying with a coating thickness of 0.2 mm, and bake at 150 °C for 40 min to obtain a coating. Treat the obtained coatings in an open flame at 800 °C for 24 h and 240 h respectively, and test their properties. Among them, the adhesion is tested with reference to GB / T 9286-1998, and the hardness is tested with reference to GB / T 6739 1996. The test results are shown in Table 1 below.

[0082] Table 1 Test Results

[0083]

[0084] As can be seen from the above test results, the fire-resistant powder coating of the present invention can still maintain good adhesion and hardness after long-term open flame treatment, and there are no cracks or the cracks are not obvious in appearance. Each component of the coating of the present invention can maintain a relatively dense coating film at high temperatures and has long-term fire resistance. In the formula of Comparative Example 1, polysiloxane is not used, and in the formula of Comparative Example 2, hexaphenoxycyclotriphosphazene is not contained, and the performance of the coating after open flame treatment drops severely; in Comparative Example 3, aromatic diamine is used, and the fire resistance drops.

[0085] Finally, it should be emphasized that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A fire-resistant powder coating, characterized in that Comprising raw materials in the following parts by mass: 100 parts of phenolic epoxy resin; 20 - 30 parts of aromatic triamine; 10 - 20 parts of amino - terminated polydimethylsiloxane; 10 - 20 parts of polyphenylmethylsiloxane; 10 - 15 parts of pentaerythritol glycidyl ether; 5 - 10 parts of hexaphenoxycyclotriphosphazene; 60 - 80 parts of inorganic filler, and the inorganic filler includes flaky alumina.

2. The intumescent powder coating according to claim 1, wherein Comprising raw materials in the following parts by mass: 100 parts of phenolic epoxy resin; 25 - 30 parts of aromatic triamine; 10 - 15 parts of amino - terminated polydimethylsiloxane; 15 - 20 parts of polyphenylmethylsiloxane; 10 - 12 parts of pentaerythritol glycidyl ether; 8 - 10 parts of hexaphenoxycyclotriphosphazene; 70 - 80 parts of inorganic filler.

3. The fire - resistant powder coating according to claim 1, characterized in that: The inorganic filler includes at least one of flaky alumina, ceramic powder, and silica; The particle size of the flaky alumina is 3 - 15 μm, the particle size of the ceramic powder is 1 - 20 μm, and the particle size of the silica is 1 - 50 μm.

4. The intumescent powder coating according to claim 3, wherein: The inorganic filler is a mixture of flaky alumina and at least one of ceramic powder and silica, and the mass content of the flaky alumina in the inorganic filler is 20 - 30%.

5. The fire - resistant powder coating according to claim 1 or 2, characterized in that: The weight - average molecular weight of the amino - terminated polydimethylsiloxane is 1000 - 1500; The weight - average molecular weight of the polyphenylmethylsiloxane is 2500 - 3000.

6. The fire - resistant powder coating according to claim 1 or 2, characterized in that: The phenolic epoxy resin is at least one of NPCN - 702 and NPCN - 704; The aromatic triamine is at least one of melamine, 1,3,5 - tris(4 - aminophenyl)benzene, and N,N',N'' - triphenyl - 1,3,5 - benzenetriamine.

7. The preparation method of the fire-resistant powder coating according to any one of claims 1 to 6, characterized in that Comprising the following steps: Step 1: Heat and mix amino - terminated polydimethylsiloxane, polyphenylmethylsiloxane, and pentaerythritol glycidyl ether evenly at the first temperature to obtain a first mixture; Step 2: Heat and mix the first mixture, phenolic epoxy resin, aromatic triamine, hexaphenoxycyclotriphosphazene, and inorganic filler evenly at the second temperature, and then cool and pulverize to obtain the fire - resistant powder coating.

8. The preparation method according to claim 7, characterized in that: In step 1, the first temperature is 120 - 130 °C, and the time for heating and mixing evenly at the first temperature is 10 - 20 min.

9. The preparation method according to claim 7 or 8, characterized in that: In step 2, the second temperature is 90 - 100 °C, and the time for heating and mixing evenly at the second temperature is 5 - 10 min.

10. The preparation method according to claim 7, characterized in that: Step 2 is carried out in a twin - screw extruder.

11. A coating, characterized in that It is formed by heating and curing the fire - resistant powder coating according to any one of claims 1 to 6, or by heating and curing the fire - resistant powder coating prepared by the preparation method according to any one of claims 7 to 10.

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