A fusion bonded epoxy coating for ladders and a method of making the same

Abstract

The application relates to the field of paint, in particular to a fusion-bonded epoxy paint for ladder rooms and a preparation method thereof. Raw materials of the fusion-bonded epoxy paint for ladder rooms include an epoxy resin composition, a functional resin, a modification aid, an accelerator, a curing agent and a leveling aid and the like. The fusion-bonded epoxy paint for ladder rooms prepared by the application not only has excellent mechanical properties and stability, but also further guarantees good waterproofness, aging resistance, corrosion resistance and other performances, effectively solves the technical problems that the existing paint products for ladder rooms are short of selection and not comprehensive in performance, and has a very excellent market prospect.

Description

Technical Field

[0001] This application relates to the field of coatings, and more particularly to a fusion-bonded epoxy coating for ladders and its preparation method. Background Technology

[0002] With the continuous development of the economy and industry, people's demand for coatings is also constantly increasing, especially for coatings with specific or high performance properties, which are in high demand in different fields and environments. Among them, stairwells, as a type of architectural space that requires coating protection, have gradually fixed performance requirements for coatings.

[0003] A stairwell is a structural space within a building used to connect different floors and facilitate the movement of people up and down. It is commonly found in tall structures such as industrial buildings, warehouses, chimneys, and water towers. It typically includes ladders, platforms, handrails, and necessary safety facilities, serving as an important vertical transportation route. The construction of stairwells usually needs to meet performance requirements such as safety, ventilation and lighting, fire resistance, durability, and waterproofing, which guides the performance requirements of coatings used in stairwells.

[0004] Given the current needs of ladder shafts, ladder shaft coatings require excellent weather resistance, corrosion resistance, aging resistance, water resistance, and abrasion resistance. However, existing coating products rarely offer performance enhancements specifically tailored to the needs of ladder shafts. This results in a limited selection of ladder shaft coatings available at present, and their performance is not comprehensive enough. Summary of the Invention

[0005] Therefore, to solve the above problems, this application provides a fusion-bonded epoxy coating for ladders and its preparation method. The fusion-bonded epoxy coating for ladders prepared by this application not only has excellent mechanical properties and stability, but also ensures good waterproofing, aging resistance, and corrosion resistance, effectively solving the technical problem of limited selection and insufficient performance of existing ladder coatings, and has a very promising market prospect.

[0006] The fusion-bonded epoxy coating for ladder compartments, by weight, comprises the following raw materials: 80-120 parts epoxy resin composition, 20-40 parts functional resin, 10-25 parts modifier, 1-6 parts accelerator, 5-10 parts curing agent, 1-3 parts leveling agent, 1-3 parts defoamer, 0.5-2 parts antioxidant, and 4-8 parts pigments and fillers.

[0007] As one specific implementation, the epoxy resin composition has a mass ratio of functional resin to modifying agent of (9~11):(2.5~3.5):(1.5~2).

[0008] In one specific embodiment, the epoxy resin composition has a mass ratio of functional resin to modifying agent of 10:3:1.5.

[0009] As one specific embodiment, the epoxy resin composition is a composition of phenolic modified epoxy resin, bisphenol A epoxy resin and bisphenol F epoxy resin.

[0010] As one specific implementation, the epoxy equivalent of the bisphenol A epoxy resin is 400~550 g / eq.

[0011] As one specific implementation, the mass ratio of the phenolic modified epoxy resin, bisphenol A epoxy resin and bisphenol F epoxy resin is (0.5~1.5):(3~4):(1~2).

[0012] As one specific implementation, the mass ratio of the phenolic modified epoxy resin, bisphenol A epoxy resin and bisphenol F epoxy resin is (1~1.2):(3.5~4):(1.5~2).

[0013] As a specific implementation scheme, the preparation method of the functional resin includes the following steps: S1: Add a mixed solvent of bisphenol A epoxy resin, cyclohexanone, and propylene glycol methyl ether acetate to a reaction vessel, and stir at 300-400 rpm for 30-40 min at 60-70°C; S2: Add hexafluorobutyl acrylate, 4-vinylbenzocyclobutene, and dodecyl mercaptan in sequence and continue stirring until completely dispersed, then raise the temperature to 120-130°C, add dicumyl peroxide, and react at a constant temperature for 2-3 h under nitrogen protection; S3: Continue to raise the temperature to 140-145°C, add dicumyl peroxide, and continue reacting for 3-4 h. After completion, cool down to 80-85°C and remove the solvent under vacuum of -0.09 to -0.08 MPa to obtain the final product.

[0014] In one specific implementation, the mass ratio of cyclohexanone to propylene glycol methyl ether acetate in the mixed solvent of cyclohexanone and propylene glycol methyl ether acetate is (3~3.5):1.

[0015] As one specific implementation, the mass ratio of the bisphenol A epoxy resin, hexafluorobutyl acrylate, 4-vinylbenzocyclobutene and dodecyl mercaptan is (9.5~10):(2~2.2):(1~1.4):(0.6~0.8).

[0016] In one specific implementation, the modifying agent is an epoxy block polymer.

[0017] As one specific implementation, the epoxy block polymer is an ethylene oxide-propylene oxide block copolymer.

[0018] As one specific embodiment, the epoxy block polymer is a composition of ethylene oxide-propylene oxide block copolymers with a weight average molecular weight of 1500-2500 and ethylene oxide-propylene oxide block copolymers with a weight average molecular weight of 6000-12000.

[0019] As one specific implementation, the mass ratio of the ethylene oxide-propylene oxide block copolymer with a weight average molecular weight of 1500~2500 to the ethylene oxide-propylene oxide block copolymer with a weight average molecular weight of 6000~12000 is (3~5):(1~2).

[0020] As one specific implementation, the mass ratio of the ethylene oxide-propylene oxide block copolymer with a weight average molecular weight of 1500~2500 to the ethylene oxide-propylene oxide block copolymer with a weight average molecular weight of 6000~12000 is (3.5~4.5):(1~1.1).

[0021] The epoxy block polymers added in this application not only significantly enhance the mechanical properties of the fusion-bonded epoxy coating but also effectively improve its corrosion resistance and water resistance. The added epoxy block polymers provide a good flow carrier for the modified particles and participate in the cross-linking and curing process of the epoxy resin composition, thus acting as intermediate links in the formed three-dimensional network structure, resulting in a denser coating structure. Under external forces, the mechanical reinforcing effect of its block segments can be fully utilized. Furthermore, the addition of block copolymers of different molecular weights can form a multi-layered composite encapsulation structure. This structure increases the steric hindrance between active molecules, thereby increasing the contact resistance between active molecules and reducing the contact frequency. Under specific conditions, this can effectively inhibit the generation of internal chemical reactions, resulting in better polymer surface properties and chemical corrosion resistance.

[0022] As one specific implementation, the promoter is at least one of imidazoles or cycloamidines.

[0023] In one specific implementation, the promoter is 2-methylimidazole.

[0024] As one specific implementation scheme, the curing agent is any one of the dicyandiamide curing agents.

[0025] As one specific implementation, the mass ratio of the accelerator to the curing agent is (3~5):(6~8).

[0026] As one specific implementation, the leveling agent is an acrylate leveling agent.

[0027] As one specific implementation scheme, the defoamer is any one of the organosilicon defoamers.

[0028] As one specific implementation, the antioxidant is at least one of antioxidant 1010, antioxidant 1076, antioxidant 1135, antioxidant 1098, and antioxidant 1330.

[0029] As one specific implementation, the antioxidant is antioxidant 1076.

[0030] As one specific implementation, the mass ratio of the epoxy resin composition to the pigments and fillers is (9~11):(0.5~0.6).

[0031] As one specific implementation, the pigment / filler is at least one of titanium dioxide, carbon black, iron oxide red, iron oxide yellow, phthalocyanine blue, phthalocyanine green, and permanent red.

[0032] The second aspect of this application provides a method for preparing the above-mentioned fusion-bonded epoxy coating for ladders. The preparation method includes the following steps: S1: Weigh all raw materials according to the required weight parts, mix them and add them to a high-speed mixer to mix evenly to obtain a mixture; S2: Add the mixture to a twin-screw extruder for melt extrusion, the extrusion temperature is 100~120℃, the extrusion frequency is 50~80Hz, the extruded material is cooled by the pressure roller, ground and sieved to obtain the fusion-bonded epoxy coating.

[0033] The beneficial effects of this application are:

[0034] 1. The fusion-bonded epoxy coating for ladder passages provided in this application not only has excellent mechanical properties and stability, but also ensures good waterproofing, aging resistance, and corrosion resistance. It effectively solves the technical problem of the lack of selection and insufficient performance of existing ladder passage coatings, and has a very promising market prospect.

[0035] 2. The fusion-bonded epoxy coating for ladders provided in this application helps to reduce the surface energy of the coating and improve the surface hydrophobicity by adding functional resins. Furthermore, the introduction of active groups forms a three-dimensional cross-linked network with the epoxy resin, which improves the coating hardness and heat resistance. It can also further enhance the impermeability by grafting long-chain alkyl groups while adjusting the length of the grafted chains to avoid brittleness caused by excessive cross-linking, thereby enhancing the overall performance of the coating.

[0036] 3. The fusion-bonded epoxy coating for ladders provided in this application incorporates epoxy block polymers, which not only significantly enhance the mechanical properties of the fusion-bonded epoxy coating but also effectively improve its corrosion resistance and water resistance. The added epoxy block polymers provide a good flow carrier for the modified particles and participate in the cross-linking and curing process of the epoxy resin composition, thus acting as intermediate links in the formed three-dimensional network structure, resulting in a denser coating structure. Under external force, the mechanical reinforcing effect of its block segments is fully utilized. Furthermore, the addition of block copolymers of different molecular weights can form a multi-layered composite encapsulation structure. The presence of this structure increases the steric hindrance between active molecules, thereby increasing the contact resistance between active molecules. Detailed Implementation

[0037] The technical solutions described above in this application will be further explained and demonstrated below with specific implementation schemes.

[0038] Example 1

[0039] A fusion-bonded epoxy coating for ladder rooms, comprising, by weight, 100 parts epoxy resin composition, 30 parts functional resin, 15 parts modifying additives, 4.5 parts accelerator, 8 parts curing agent, 2 parts leveling agent, 1 part defoamer, 1.5 parts antioxidant, and 6 parts pigments and fillers.

[0040] The epoxy resin composition is a combination of phenolic modified epoxy resin, bisphenol A epoxy resin and bisphenol F epoxy resin in a mass ratio of 1.2:3.8:2.

[0041] Bisphenol A epoxy resin was purchased from Baling Petrochemical's E-20 epoxy resin, with an average epoxy equivalent of 500 g / eq; bisphenol F epoxy resin was purchased from Kunshan Guodu Chemical's YDF-2001 epoxy resin; and phenolic modified epoxy resin was purchased from Baling Petrochemical's 704 epoxy resin.

[0042] The preparation method of the functional resin includes the following steps, in parts by weight: S1: 9.8 parts of bisphenol A epoxy resin and 50 parts of a mixed solvent of cyclohexanone and propylene glycol methyl ether acetate (mass ratio of cyclohexanone and propylene glycol methyl ether acetate is 3:1) are added to a reaction vessel and stirred at 300 rpm for 40 min at 65 °C; S2: 2.1 parts of hexafluorobutyl acrylate, 1.2 parts of 4-vinylbenzocyclobutene and 0.6 parts of dodecyl mercaptan are added sequentially and stirred until completely dispersed. Then the temperature is raised to 120 °C, and 0.08 parts of dicumyl peroxide are added. The reaction is carried out at a constant temperature for 3 h under nitrogen protection; S3: The temperature is raised to 140 °C, and 0.1 parts of dicumyl peroxide are added and the reaction is continued for 4 h. After completion, the temperature is lowered to 85 °C and the solvent is removed under a vacuum of -0.09 MPa. The resin is then obtained.

[0043] The modifying agent is a composition of ethylene oxide-propylene oxide block copolymer with a weight average molecular weight of 1850 and ethylene oxide-propylene oxide block copolymer with a weight average molecular weight of 7850, in a mass ratio of 4:1.1. The 1850 ethylene oxide-propylene oxide block copolymer was purchased from BASF product L43; the 7850 ethylene oxide-propylene oxide block copolymer was purchased from BASF product L87.

[0044] The accelerator is 2-methylimidazole; the curing agent is dicyandiamide curing agent K7108, purchased from Liuan Jietongda.

[0045] The leveling agent is an acrylic leveling agent, purchased from Ningbo Nanhai PV88.

[0046] The silicone defoamer is BYK-066N; the antioxidant is antioxidant 1076.

[0047] The pigment / filler is phthalocyanine blue.

[0048] A method for preparing fusion-bonded epoxy coating for ladder rooms includes the following steps: S1: Weigh all raw materials according to the required weight parts, mix them and add them to a high-speed mixer to mix evenly to obtain a mixture; S2: Add the mixture to a twin-screw extruder for melt extrusion at an extrusion temperature of 110℃ and an extrusion frequency of 65Hz. After extrusion, the material is cooled by the pressure roller and ground through a 200-mesh sieve to obtain the fusion-bonded epoxy coating.

[0049] Example 2

[0050] A fusion-bonded epoxy coating for ladder rooms, comprising, by weight, 110 parts epoxy resin composition, 25 parts functional resin, 20 parts modifying additives, 4.5 parts accelerator, 8 parts curing agent, 2 parts leveling agent, 1 part defoamer, 1.5 parts antioxidant, and 6 parts pigments and fillers.

[0051] The epoxy resin composition is a combination of phenolic modified epoxy resin, bisphenol A epoxy resin and bisphenol F epoxy resin in a mass ratio of 0.8:4:1.

[0052] Bisphenol A epoxy resin was purchased from Baling Petrochemical's E-20 epoxy resin; bisphenol F epoxy resin was purchased from Kunshan Guodu Chemical's YDF-2001 epoxy resin; and phenolic modified epoxy resin was purchased from Baling Petrochemical's 704 epoxy resin.

[0053] The preparation method of the functional resin includes the following steps, in parts by weight: S1: 9.8 parts of bisphenol A epoxy resin and 50 parts of a mixed solvent of cyclohexanone and propylene glycol methyl ether acetate (mass ratio of cyclohexanone and propylene glycol methyl ether acetate is 3:1) are added to a reaction vessel and stirred at 300 rpm for 40 min at 65 °C; S2: 2.1 parts of hexafluorobutyl acrylate, 1.2 parts of 4-vinylbenzocyclobutene and 0.6 parts of dodecyl mercaptan are added sequentially and stirred until completely dispersed. Then the temperature is raised to 120 °C, and 0.08 parts of dicumyl peroxide are added. The reaction is carried out at a constant temperature for 3 h under nitrogen protection; S3: The temperature is raised to 140 °C, and 0.1 parts of dicumyl peroxide are added and the reaction is continued for 4 h. After completion, the temperature is lowered to 85 °C and the solvent is removed under a vacuum of -0.09 MPa. The resin is then obtained.

[0054] The modifying agent is a composition of ethylene oxide-propylene oxide block copolymer with a weight average molecular weight of 1850 and ethylene oxide-propylene oxide block copolymer with a weight average molecular weight of 7850, in a mass ratio of 4.5:1. The 1850 ethylene oxide-propylene oxide block copolymer was purchased from BASF product L43; the 7850 ethylene oxide-propylene oxide block copolymer was purchased from BASF product L87.

[0055] The accelerator is 2-methylimidazole; the curing agent is dicyandiamide curing agent K7108, purchased from Liuan Jietongda.

[0056] The leveling agent is an acrylic leveling agent, purchased from Ningbo Nanhai PV88.

[0057] The silicone defoamer is BYK-066N; the antioxidant is antioxidant 1076.

[0058] The pigment / filler is phthalocyanine blue.

[0059] A method for preparing fusion-bonded epoxy coating for ladder rooms includes the following steps: S1: Weigh all raw materials according to the required weight parts, mix them and add them to a high-speed mixer to mix evenly to obtain a mixture; S2: Add the mixture to a twin-screw extruder for melt extrusion at an extrusion temperature of 110℃ and an extrusion frequency of 65Hz. After extrusion, the material is cooled by the pressure roller and ground through a 200-mesh sieve to obtain the fusion-bonded epoxy coating.

[0060] Comparative Example 1

[0061] The specific implementation method of this comparative example is basically the same as that of Example 1, except that the epoxy resin composition is a composition of phenolic modified epoxy resin, bisphenol A epoxy resin and bisphenol F epoxy resin in a mass ratio of 0.2:5:0.5.

[0062] Comparative Example 2

[0063] The specific implementation method of this comparative example is basically the same as that of Example 1, except that the bisphenol A epoxy resin was purchased from Baling Petrochemical's E-44 epoxy resin, with an average epoxy equivalent of 220 g / eq.

[0064] Comparative Example 3

[0065] The specific implementation method of this comparative example is basically the same as that of Example 1, except that the preparation method of the functional resin includes the following steps, in parts by mass: S1: 9.8 parts of bisphenol A epoxy resin and 50 parts of a mixed solvent of cyclohexanone and propylene glycol methyl ether acetate (the mass ratio of cyclohexanone and propylene glycol methyl ether acetate is 3:1) are added to a reaction vessel and stirred at 300 rpm for 40 min at 65°C; S2: 0.25 parts of hexafluorobutyl acrylate, 2 parts of 4-vinylbenzocyclobutene and 1.2 parts of dodecyl mercaptan are added sequentially and stirred until completely dispersed. Then the temperature is raised to 120°C, and 0.08 parts of dicumyl peroxide are added. The reaction is carried out at a constant temperature for 3 h under nitrogen protection; S3: The temperature is raised to 140°C, and 0.1 parts of dicumyl peroxide are added and the reaction is continued for 4 h. After completion, the temperature is lowered to 85°C and the solvent is removed under a vacuum of -0.09 MPa. The resin is then obtained.

[0066] Comparative Example 4

[0067] The specific implementation method of this comparative example is basically the same as that of Example 1, except that the preparation method of the functional resin includes the following steps, in parts by mass: S1: 9.8 parts of bisphenol A epoxy resin and 50 parts of a mixed solvent of cyclohexanone and propylene glycol methyl ether acetate (the mass ratio of cyclohexanone and propylene glycol methyl ether acetate is 3:1) are added to a reaction vessel and stirred at 300 rpm for 40 min at 65°C; S2: 2.5 parts of hexafluorobutyl acrylate, 0.3 parts of 4-vinylbenzocyclobutene and 0.1 parts of dodecyl mercaptan are added sequentially and stirred until completely dispersed. Then the temperature is raised to 120°C, and 0.08 parts of dicumyl peroxide are added. The reaction is carried out at a constant temperature for 3 h under nitrogen protection; S3: The temperature is raised to 140°C, and 0.1 parts of dicumyl peroxide are added and the reaction is continued for 4 h. After completion, the temperature is lowered to 85°C and the solvent is removed under a vacuum of -0.09 MPa. The resin is then obtained.

[0068] Comparative Example 5

[0069] The specific implementation method of this comparative example is basically the same as that of Example 1, except that the modifying agent is an ethylene oxide-propylene oxide block copolymer with a weight average molecular weight of 1850.

[0070] Comparative Example 6

[0071] The specific implementation method of this comparative example is basically the same as that of Example 1, except that the modifying agent is a composition of ethylene oxide-propylene oxide block copolymer with a weight average molecular weight of 1850 and ethylene oxide-propylene oxide block copolymer with a weight average molecular weight of 7850, and the mass ratio of the two is 9:1.

[0072] Comparative Example 7

[0073] The specific implementation method of this comparative example is basically the same as that of Example 1, except that the modifying agent is a composition of ethylene oxide-propylene oxide block copolymer with a weight average molecular weight of 1850 and ethylene oxide-propylene oxide block copolymer with a weight average molecular weight of 7850, and the mass ratio of the two is 2:1.5.

[0074] Comparative Example 8

[0075] The specific implementation method of this comparative example is basically the same as that of Example 1, except that the modifying agent is an ethylene oxide-propylene oxide block copolymer with a weight average molecular weight of 10800, which was purchased from BASF L88 product.

[0076] Performance Evaluation

[0077] 1. The coatings prepared in the examples and comparative examples were subjected to cathodic disbondment resistance test according to the standard SY / T0315-1997. The test conditions were: 1.5V, 20℃, 28d. The results are recorded in Table 1.

[0078] 2. The coatings prepared according to the examples and comparative examples were used to prepare fusion-bonded coatings with a thickness of 400 μm. The surface water contact angle of the fusion-bonded coatings prepared according to the examples and comparative examples was tested using the seat drop method: 2 μL, 15s. The average value of 10 tests was recorded in Table 1.

[0079] 3. Water boiling aging resistance test was conducted according to standard GB / T9286-2014. The test time was 6 hours, and the results were recorded in Table 1.

[0080] Table 1 Performance Evaluation Table

[0081]

[0082] From the embodiments and comparative examples of this application, as well as the data results in Table 1, it can be seen that Examples 1 and 2 have significant performance advantages over Comparative Examples 1-7 in terms of water resistance, corrosion resistance, and aging resistance. Examples 1 and 2, through the addition of functional resins, help reduce the surface energy of the coating, improving surface hydrophobicity. Furthermore, by introducing active groups to form a three-dimensional cross-linked network with the epoxy resin, they enhance the coating's hardness and heat resistance. They can also further enhance impermeability through grafting long-chain alkyl groups while adjusting the graft chain length to avoid brittleness caused by excessive cross-linking, thereby enhancing the overall comprehensive performance of the coating.

Claims

1. A fusion-bonded epoxy coating for use in ladder compartments, characterized in that: By weight, the raw materials include: 80-120 parts of epoxy resin composition, 20-40 parts of functional resin, 10-25 parts of modifying additives, 1-6 parts of accelerator, 5-10 parts of curing agent, 1-3 parts of leveling agent, 1-3 parts of defoamer, 0.5-2 parts of antioxidant, and 4-8 parts of pigments and fillers. The epoxy resin composition is a composition of phenolic modified epoxy resin, bisphenol A epoxy resin and bisphenol F epoxy resin; The mass ratio of the phenolic modified epoxy resin, bisphenol A epoxy resin, and bisphenol F epoxy resin is (0.5~1.5):(3~4):(1~2). The preparation method of the functional resin includes the following steps: S1: Add a mixed solvent of bisphenol A epoxy resin, cyclohexanone, and propylene glycol methyl ether acetate to a reaction vessel, and stir at 300-400 rpm for 30-40 min at 60-70°C; S2: Add hexafluorobutyl acrylate, 4-vinylbenzocyclobutene, and dodecyl mercaptan in sequence and continue stirring until completely dispersed, then raise the temperature to 120-130°C, add dicumyl peroxide, and react at a constant temperature for 2-3 h under nitrogen protection; S3: Continue to raise the temperature to 140-145°C, add dicumyl peroxide, and continue to react for 3-4 h. After completion, cool down to 80-85°C and remove the solvent under vacuum of -0.09--0.08 MPa to obtain the final product. In the mixed solvent of cyclohexanone and propylene glycol methyl ether acetate, the mass ratio of cyclohexanone to propylene glycol methyl ether acetate is (3~3.5):

1. The mass ratio of bisphenol A epoxy resin, hexafluorobutyl acrylate, 4-vinylbenzocyclobutene, and dodecyl mercaptan is (9.5~10):(2~2.2):(1~1.4):(0.6~0.8). The modifying agent is an epoxy block polymer; The epoxy block polymer is a composition of ethylene oxide-propylene oxide block copolymer with a weight average molecular weight of 1500-2500 and ethylene oxide-propylene oxide block copolymer with a weight average molecular weight of 6000-12000, with a mass ratio of (3-5):(1-2).

2. The fusion-bonded epoxy coating for ladder compartments according to claim 1, characterized in that: The epoxy resin composition has a mass ratio of functional resin to modifying agent of (9~11):(2.5~3.5):(1.5~2).

3. The fusion-bonded epoxy coating for ladder compartments according to claim 2, characterized in that: The promoter is at least one of imidazole or cycloamidinium.

4. The fusion-bonded epoxy coating for ladder compartments according to claim 3, characterized in that: The curing agent is any one of the dicyandiamide curing agents.

5. The fusion-bonded epoxy coating for ladder compartments according to claim 4, characterized in that: The mass ratio of the epoxy resin composition to the pigments and fillers is (9~11):(0.5~0.6); the pigments and fillers are at least one of titanium dioxide, carbon black, iron oxide red, iron oxide yellow, phthalocyanine blue, phthalocyanine green, and permanent red.

6. A method for preparing a fusion-bonded epoxy coating for ladders according to any one of claims 1 to 5, characterized in that: Preparation method Includes the following steps: S1: Weigh all raw materials according to the required weight proportions, mix them and add them to a high-speed mixer to mix evenly to obtain a mixture; S2: Add the mixture to a twin-screw extruder for melt extrusion, with an extrusion temperature of 100~120℃ and an extrusion frequency of 50~80Hz. After extrusion, cool the material by the pressure roller, grind and sieve it to obtain the fusion-bonded epoxy coating.

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