Bio-based polyurethane anticorrosive paint as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of anticorrosive paint, and relates to bio-based polyurethane anticorrosive paint as well as a preparation method and application thereof. The bio-based polyurethane anticorrosive paint comprises a component A and a component B, the component A comprises the following components: bio-based polyol, pigment filler, a first plasticizer, a modified polymer unsaturated carboxylate dispersant, a fluorine modified polyacrylate leveling agent, a defoaming agent and a first mixed solvent, and the component B comprises the following components: polypropylene glycol ether, polyether glycerol, a second plasticizer, diisocyanate and a second mixed solvent. According to the invention, the bio-based polyol containing a benzene ring rigid group is adopted as a raw material and is combined with a preparation process, so that the adhesive force, the salt fog resistance, the elongation at break, the 5% H2SO4 soaking resistance and the storage stability of the bio-based polyurethane anticorrosive paint are remarkably improved; and the dosage of xylene is reduced, the VOC content is obviously reduced, and the paint is environment-friendly.

Description

Technical Field

[0001] The present invention belongs to the technical field of anticorrosive coatings, and relates to a bio-based polyurethane anticorrosive coating, its preparation method and application. Background Art

[0002] With the upgrading of the corrosion protection requirements of industrial facilities, polyurethane anticorrosive coatings have become the mainstream choice due to their excellent mechanical strength and chemical resistance. However, traditional petroleum-based polyurethane coatings rely on non-renewable resources, and the VOCs (about 300 - 500 g / L) and CO2 emissions (about 2.8 tons of CO2 equivalent per ton of coating) generated during their production seriously violate the "dual carbon" strategic goal. In addition, the salt spray resistance performance of petroleum-based coatings is generally limited within 2000 h, making it difficult to meet the long-term protection requirements of extreme environments such as ocean engineering.

[0003] In recent years, bio-based polyurethane materials have made progress in the foam field, but their application in anticorrosive coatings still has significant bottlenecks. For example, (1) performance imbalance: In order to increase the biomass content of existing bio-based coatings, the crosslinking density is often sacrificed, resulting in a decrease in chemical resistance (immersion in 5% H2SO4 < 120 h); (2) process defects: Traditional dehydration processes (such as atmospheric pressure heating) are difficult to control the water content of polyether polyols below 0.05%, leading to side reactions and poor storage stability of the coatings (viscosity increase > 30% within 6 months); (3) scale-up problems: The batch production in reaction kettles has problems such as high energy consumption (power consumption per ton of product ≥ 150 kWh) and poor batch consistency (salt spray resistance time fluctuation ± 15%), restricting industrial application. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a bio-based polyurethane anticorrosive coating, its preparation method and application in view of the deficiencies of the prior art.

[0005] To solve the above technical problems, the technical solutions adopted by the present invention are as follows:

[0006] The present invention discloses a bio-based polyurethane anticorrosive coating, which includes component A and component B;

[0007] Among them, component A includes the following components in parts by weight:

[0008] Bio-based polyol, 45.0 - 55.0 parts;

[0009] Pigment and filler, 32.0 - 38.0 parts;

[0010] First plasticizer, 4.0 - 8.0 parts;

[0011] Modified polymer unsaturated carboxylate dispersant, 3.0 - 6.0 parts;

[0012] Fluorine-modified polyacrylate leveling agent, 1.0 to 4.0 parts;

[0013] Defoamer, 0.6 to 1.5 parts;

[0014] First mixed solvent, 25.0 to 30.0 parts;

[0015] Among them, the B component includes the following components in parts by weight:

[0016] Polypropylene glycol ether, 30.0 to 40.0 parts;

[0017] Polyether glycerol, 15.0 to 25.0 parts;

[0018] Second plasticizer, 8.0 to 15.0 parts;

[0019] Diisocyanate, 8.0 to 12.0 parts;

[0020] Second mixed solvent, 15.0 to 25.0 parts;

[0021] Among them, the mass ratio of the A component to the B component is (1.0 to 1.2):(1.0 to 1.2).

[0022] In some embodiments, preferably, the bio-based polyurethane anticorrosive coating comprises an A component and a B component;

[0023] Among them, the A component includes the following components in parts by weight:

[0024] Bio-based polyol, 45.0 to 55.0 parts;

[0025] Pigment and filler, 33.0 to 37.0 parts;

[0026] First plasticizer, 4.0 to 6.0 parts;

[0027] Modified polymer unsaturated carboxylate dispersant, 3.0 to 4.0 parts;

[0028] Fluorine-modified polyacrylate leveling agent, 1.0 to 2.0 parts;

[0029] Defoamer, 0.6 to 1.0 parts;

[0030] First mixed solvent, 25.0 to 30.0 parts;

[0031] Among them, the B component includes the following components in parts by weight:

[0032] Polypropylene glycol ether, 35.0 to 40.0 parts;

[0033] Polyether glycerol, 15.0 to 20.0 parts;

[0034] The second plasticizer, 10.0 to 14.0 parts;

[0035] Diisocyanate, 8.0 to 9.0 parts;

[0036] The second mixed solvent, 18.0 to 22.0 parts;

[0037] Wherein, the mass ratio of the component A to the component B is 1.0:1.0.

[0038] In some embodiments, the bio-based polyol is bio-based polyol FHB-275; and / or, the pigment and filler is any one or a combination of several of wet ground mica powder, rutile titanium dioxide, barite powder, talc powder, zinc phosphate, aluminum tripolyphosphate and micaceous iron oxide; and / or, the first plasticizer is any one or a combination of several of diisononyl phthalate, dioctyl terephthalate, dioctyl adipate and poly(propylene adipate); the modified polymer unsaturated carboxylate dispersant is any one or a combination of several of ammonium acrylate-maleic anhydride copolymer, sodium acrylate-maleic anhydride copolymer, sodium dodecylbenzenesulfonate, acrylic acid copolymer and polyurethane-modified polymer dispersant BYK-190; and / or, the fluorine-modified polyacrylate leveling agent is any one or a combination of several of perfluorooctyl methacrylate-butyl acrylate copolymer BYK-380N, acrylate copolymer BYK-358N, polyether-modified polydimethylsiloxane BYK-333 and acrylate dispersant BYK-154; and / or, the defoaming agent is any one or a combination of several of polydimethylsiloxane, polyether-modified silicone BYK-088 and polyether defoaming agent BYK-1799; and / or, the first mixed solvent is any one or a combination of several of a mixture of xylene and butyl acetate in any proportion, a mixture of ethyl acetate and propylene glycol monomethyl ether in any proportion, a mixture of ethanol and acetone in any proportion and a mixture of ethyl acetoacetate and dipropylene glycol methyl ether in any proportion; and / or, the second plasticizer is any one or a combination of several of diisononyl phthalate, dioctyl terephthalate, dioctyl adipate and poly(propylene adipate); and / or, the diisocyanate is diphenylmethane diisocyanate or isophorone diisocyanate; and / or, the second mixed solvent is any one or a combination of several of a mixture of xylene and butyl acetate in any proportion, a mixture of ethyl acetate and propylene glycol monomethyl ether in any proportion, a mixture of ethanol and acetone in any proportion and a mixture of ethyl acetoacetate and dipropylene glycol methyl ether in any proportion.

[0039] In some embodiments, preferably, the bio-based polyol is bio-based polyol FHB-275, purchased from Zhangjiagang Feihang Technology Co., Ltd., a yellow liquid, with a hydroxyl value of 275 ± 20 mg KOH / g, an acid value of ≤ 5.0 mg KOH / g, and a viscosity of 250 ± 100 cps @ 25°C; it is detected that the bio-based polyol FHB-275 contains a benzene ring structure.

[0040] Among them, the bio-based polyurethane anticorrosive coating of the present invention uses polymethylene polyphenyl polyisocyanate and a modified bio-based polyol (containing a rigid group, such as a benzene ring) as the main film-forming substances. Since there are many isocyanate groups on the main chain of the isocyanate adduct, the hydroxyl group containing active hydrogen in the bio-based polyol reacts with the isocyanate group to form a polyester-based polyurethane, and an excellent bio-based polyurethane anticorrosive coating with comprehensive mechanical properties and resistance to acids, alkalis, salts, etc. can be obtained. Since the bio-based polyol contains multiple hydroxyl groups and the diisocyanate has multiple isocyanate groups, a three-dimensional network structure with a very high crosslinking density can be formed, and the formed coating film has excellent chemical medium resistance.

[0041] In some embodiments, preferably, the pigment and filler is any one or a combination of several of wet-ground sericite powder, rutile titanium dioxide, and barite powder.

[0042] In some embodiments, preferably, the first plasticizer is diisononyl phthalate.

[0043] In some embodiments, preferably, the modified polymer unsaturated carboxylate dispersant is an ammonium salt of acrylic acid-maleic anhydride copolymer.

[0044] In some embodiments, preferably, the fluorine-modified polyacrylate leveling agent is a copolymer of perfluorooctyl methacrylate-butyl acrylate BYK-380N.

[0045] In some embodiments, preferably, the defoaming agent is polydimethylsiloxane.

[0046] In some embodiments, preferably, the first mixed solvent is a mixture of xylene and butyl acetate with a volume ratio of (3 - 4):(1 - 2).

[0047] In some embodiments, preferably, the first mixed solvent is a mixture of ethyl acetate and propylene glycol methyl ether with a volume ratio of (2 - 3):(1 - 2).

[0048] In some embodiments, preferably, the second plasticizer is diisononyl phthalate.

[0049] In some embodiments, preferably, the second mixed solvent is a mixture of xylene and butyl acetate with a volume ratio of (3 - 4):(1 - 2).

[0050] In some embodiments, preferably, the first mixed solvent is a mixture of ethyl acetate and propylene glycol methyl ether with a volume ratio of (2-3):(1-2).

[0051] In some embodiments, the A component of the bio-based polyurethane anticorrosive coating further includes inorganic nano-fillers and a CO2 absorbent;

[0052] Among them, the A component includes the following components in parts by weight:

[0053] Bio-based polyol, 45.0-55.0 parts;

[0054] Pigment and filler, 32.0-38.0 parts;

[0055] First plasticizer, 4.0-8.0 parts;

[0056] Modified polymer unsaturated carboxylate dispersant, 3.0-6.0 parts;

[0057] Fluorine-modified polyacrylate leveling agent, 1.0-4.0 parts;

[0058] Defoamer, 0.6-1.5 parts;

[0059] First mixed solvent, 25.0-30.0 parts;

[0060] Inorganic nano-fillers, 1.0-1.2 parts;

[0061] CO2 absorbent, 0.3-0.5 parts.

[0062] In some embodiments, the bio-based polyurethane anticorrosive coating includes an A component and a B component; the A component of the bio-based polyurethane anticorrosive coating further includes inorganic nano-fillers and a CO2 absorbent;

[0063] Among them, the A component includes the following components in parts by weight:

[0064] Bio-based polyol, 45.0-55.0 parts;

[0065] Pigment and filler, 32.0-38.0 parts;

[0066] First plasticizer, 4.0-8.0 parts;

[0067] Modified polymer unsaturated carboxylate dispersant, 3.0-6.0 parts;

[0068] Fluorine-modified polyacrylate leveling agent, 1.0-4.0 parts;

[0069] Defoamer, 0.6-1.5 parts;

[0070] The first mixed solvent, 25.0 to 30.0 parts;

[0071] Inorganic nano filler, 1.0 to 1.2 parts;

[0072] CO2 absorbent, 0.3 to 0.5 parts;

[0073] Among them, the B component includes the following components in parts by weight:

[0074] Polypropylene glycol ether, 30.0 to 40.0 parts;

[0075] Polyether glycerol, 15.0 to 25.0 parts;

[0076] The second plasticizer, 8.0 to 15.0 parts;

[0077] Diisocyanate, 8.0 to 12.0 parts;

[0078] The second mixed solvent, 15.0 to 25.0 parts;

[0079] Among them, the mass ratio of the A component to the B component is (1.0 to 1.2):(1.0 to 1.2).

[0080] In some embodiments, preferably, the A component of the bio-based polyurethane anticorrosive coating further includes an inorganic nano filler and a CO2 absorbent;

[0081] Among them, the A component includes the following components in parts by weight:

[0082] Bio-based polyol, 45.0 to 55.0 parts;

[0083] Pigment and filler, 33.0 to 37.0 parts;

[0084] The first plasticizer, 4.0 to 6.0 parts;

[0085] Modified polymer unsaturated carboxylate dispersant, 3.0 to 4.0 parts;

[0086] Fluorine-modified polyacrylate leveling agent, 1.0 to 2.0 parts;

[0087] Defoamer, 0.6 to 1.0 parts;

[0088] The first mixed solvent, 25.0 to 30.0 parts;

[0089] Inorganic nano filler, 1.2 parts;

[0090] CO2 absorbent, 0.3 parts.

[0091] In some embodiments, preferably, the bio-based polyurethane anti-corrosion coating comprises a component A and a component B; the component A of the bio-based polyurethane anti-corrosion coating further comprises inorganic nano-fillers and a CO2 absorbent;

[0092] Among them, the component A comprises the following components in parts by weight:

[0093] Bio-based polyol, 45.0 to 55.0 parts;

[0094] Pigment and filler, 33.0 to 37.0 parts;

[0095] The first plasticizer, 4.0 to 6.0 parts;

[0096] Modified polymer unsaturated carboxylate dispersant, 3.0 to 4.0 parts;

[0097] Fluorine-modified polyacrylate leveling agent, 1.0 to 2.0 parts;

[0098] Defoamer, 0.6 to 1.0 part;

[0099] The first mixed solvent, 25.0 to 30.0 parts;

[0100] Inorganic nano-fillers, 1.2 parts;

[0101] CO2 absorbent, 0.3 part;

[0102] Among them, the component B comprises the following components in parts by weight:

[0103] Polypropylene glycol ether, 35.0 to 40.0 parts;

[0104] Polyether glycerol, 15.0 to 20.0 parts;

[0105] The second plasticizer, 10.0 to 14.0 parts;

[0106] Diisocyanate, 8.0 to 9.0 parts;

[0107] The second mixed solvent, 18.0 to 22.0 parts;

[0108] Among them, the mass ratio of the component A to the component B is 1.0:1.0.

[0109] In some embodiments, when the component A of the bio-based polyurethane anti-corrosion coating further comprises inorganic nano-fillers and a CO2 absorbent, the inorganic nano-fillers are any one or a combination of several of nano-silica, nano-titanium dioxide, nano-aluminum oxide, nano-zinc oxide and nano-ferric oxide, and the CO2 absorbent is any one or a combination of several of calcium oxide, calcium hydroxide, potassium carbonate and sodium hydroxide.

[0110] In some embodiments, preferably, when the inorganic nano-filler and the CO2 absorbent are further included in the component A of the bio-based polyurethane anticorrosive coating, the inorganic nano-filler is nano-titanium dioxide and the CO2 absorbent is calcium oxide.

[0111] Furthermore, the present invention discloses a preparation method of the above-mentioned bio-based polyurethane anticorrosive coating, which includes the following steps:

[0112] (1) Add the first mixed solvent, fluorine-modified polyacrylate leveling agent, first plasticizer, and modified polymer unsaturated carboxylate dispersant in the weight parts described in any one of claims 1 to 4 into the first reaction kettle and mix evenly; then add the bio-based polyol in the weight parts, mix well, and perform atmospheric dehydration; then add the pigment and filler in the weight parts and mix evenly; then pump the reaction material into the second reaction kettle for the first vacuum dehydration; after the dehydration is completed, transfer the reaction mixture to a grinder for grinding; finally, add the defoaming agent in the weight parts and mix evenly to obtain component A.

[0113] (2) Add the polypropylene glycol ether, polyether glycerol, and toluene in the weight parts described in any one of claims 1 to 4 into the third reaction kettle for the second vacuum dehydration, and cool down after the vacuum dehydration ends to obtain a polypropylene glycol ether / polyether glycerol mixture; preheat the diisocyanate and the second plasticizer in the weight parts in the fourth reaction kettle to obtain a diisocyanate / second plasticizer mixture; mix the polypropylene glycol ether / polyether glycerol mixture and the diisocyanate / second plasticizer mixture and carry out a polymerization reaction; after the reaction ends, cool down the reaction system, dilute it with the second mixed solvent, filter it through a filter, and discharge it to obtain component B.

[0114] (3) Mix component A and component B evenly through a static mixer, stand for defoaming, and then obtain the bio-based polyurethane anticorrosive coating.

[0115] Among them, in step (2), when the polypropylene glycol ether / polyether glycerol mixture and the diisocyanate / second plasticizer mixture are mixed, it is preferred to drop the polypropylene glycol ether / polyether glycerol mixture into the preheated mixture of diisocyanate and the first plasticizer at a constant rate (18 - 30 kg / h, preferably 18 - 25 kg / h, and further preferably 20 kg / h) through an accurate metering pump.

[0116] In some embodiments, in step (1), the atmospheric pressure dehydration is carried out at 105 - 125°C; and / or, the first reduced pressure dehydration is carried out at 110°C - 130°C; and / or, the pressure of the first reduced pressure dehydration is -0.095 MPa to -0.090 MPa; and / or, the first reduced pressure dehydration can end when the water content is less than or equal to 0.10%; and / or, the grinding grinds the material to a particle size less than or equal to 30 μm.

[0117] In some embodiments, preferably, in step (1), the atmospheric pressure dehydration is carried out at 110 - 120°C.

[0118] In some embodiments, more preferably, in step (1), the atmospheric pressure dehydration is carried out at 120°C.

[0119] Among them, the atmospheric pressure dehydration is carried out until no water flows out.

[0120] In some embodiments, preferably, in step (1), the first reduced pressure dehydration is carried out at 110°C - 130°C.

[0121] In some embodiments, more preferably, in step (1), the first reduced pressure dehydration is carried out at 115°C - 125°C.

[0122] In some embodiments, preferably, in step (1), the grinding grinds the material to a particle size less than or equal to 20 μm.

[0123] Among them, the preparation of the component A adopts a continuous double-kettle dehydration system. After premixing, dispersion and atmospheric pressure dehydration are completed in the first reaction kettle, it continuously enters the second reaction kettle through a transfer pump for reduced pressure dehydration. The dehydrated material directly enters the filling line through an on-line grinding system, and the whole process is uninterrupted.

[0124] In some embodiments, in step (2), the second reduced pressure dehydration is carried out at 120°C - 140°C; and / or, the pressure of the second reduced pressure dehydration is -0.100 MPa to -0.095 MPa; and / or, the second reduced pressure dehydration can end when the water content is less than or equal to 0.10%; and / or, after the reduced pressure dehydration ends, cooling is carried out to 70°C - 90°C; and / or, the preheating is carried out to 70°C - 90°C; and / or, the polymerization reaction is carried out at a reaction temperature of 70°C - 90°C; and / or, the reaction time of the polymerization reaction is 1.0 - 5.0 hours; and / or, the polymerization reaction is carried out under the protection of an inert gas; and / or, after the reaction ends, the reaction system is cooled to below 70°C; and / or, the filter filtration is carried out through a 2 μm - 20 μm filter screen.

[0125] In some embodiments, preferably, in step (2), the second vacuum dehydration is carried out at 125°C to 130°C.

[0126] In some embodiments, preferably, in step (2), after the vacuum dehydration is completed, the temperature is reduced to 75°C to 80°C.

[0127] In some embodiments, preferably, in step (2), the preheating is carried out to 75°C to 80°C.

[0128] In some embodiments, preferably, in step (2), for the polymerization reaction, the reaction temperature is 75°C to 85°C.

[0129] In some embodiments, preferably, in step (2), for the polymerization reaction, the reaction time is 1.0 to 3.0 hours.

[0130] Among them, the inert gas is preferably nitrogen.

[0131] Among them, during the polymerization reaction, nitrogen is introduced and vacuum is pumped for 0.2 to 2.0 hours to remove residual bubbles.

[0132] In some embodiments, preferably, in step (2), for the filtration by the filter, filtration is carried out through a 2μm to 10μm filter mesh.

[0133] In some embodiments, further preferably, in step (2), for the filtration by the filter, filtration is carried out through a 2μm to 5μm filter mesh.

[0134] In some embodiments, in step (3), the mass ratio of the component A to the component B is (1.0 to 1.2):(1.0 to 1.2).

[0135] In some embodiments, preferably, in step (3), the mass ratio of the component A to the component B is 1.0:1.0.

[0136] In some embodiments, when the component A further includes inorganic nano-fillers and a CO2 absorbent, the preparation method of the above-mentioned bio-based polyurethane anticorrosive coating includes the following steps:

[0137] (1) Add the first mixed solvent, fluorine-modified polyacrylate leveling agent, first plasticizer, and modified polymer unsaturated carboxylate dispersant in the weight parts described in any one of claims 1 to 4 to the first reaction kettle and mix evenly; then add the weight parts of the bio-based polyol, mix well, and perform atmospheric dehydration; then add the weight parts of the pigment and filler, and mix evenly; continue to add the weight parts of the inorganic nano-filler and CO2 absorbent, and mix evenly; then pump the reaction material into the second reaction kettle for the first vacuum dehydration; after the dehydration is completed, transfer the reaction mixture to a grinder for grinding; finally, add the weight parts of the defoaming agent, mix evenly, and obtain Component A;

[0138] (2) Add the polypropylene glycol ether, polyether glycerol, and toluene in the weight parts described in any one of claims 1 to 4 to the third reaction kettle, perform the second vacuum dehydration, and cool down after the vacuum dehydration is completed to obtain a polypropylene glycol ether / polyether glycerol mixture; preheat the weight parts of the diisocyanate and the second plasticizer in the fourth reaction kettle to obtain a diisocyanate / second plasticizer mixture; mix the polypropylene glycol ether / polyether glycerol mixture and the diisocyanate / second plasticizer mixture, and perform a polymerization reaction; after the reaction is completed, cool down the reaction system, dilute with the weight parts of the second mixed solvent, filter with a filter, and discharge to obtain Component B;

[0139] (3) Mix Component A and Component B evenly through a static mixer, and let it stand for defoaming to obtain the bio-based polyurethane anticorrosive coating.

[0140] In some embodiments, in step (1), the atmospheric dehydration is carried out at 105 - 125 °C; and / or, the first vacuum dehydration is carried out at 110 °C - 130 °C; and / or, the pressure of the first vacuum dehydration is -0.095 MPa to -0.090 MPa; and / or, the first vacuum dehydration can be ended until the water content is less than or equal to 0.10%; and / or, the grinding grinds the material to a particle size less than or equal to 30 μm.

[0141] In some embodiments, preferably, in step (1), the atmospheric dehydration is carried out at 110 - 120 °C.

[0142] In some embodiments, more preferably, in step (1), the atmospheric dehydration is carried out at 120 °C.

[0143] Among them, the atmospheric dehydration is carried out until no water flows out.

[0144] In some embodiments, preferably, in step (1), the first vacuum dehydration is carried out at 110 °C - 130 °C.

[0145] In some embodiments, further preferably, in step (1), the first vacuum dehydration is carried out at 115°C to 125°C.

[0146] In some embodiments, preferably, in step (1), the grinding grinds the material to a particle size less than or equal to 20 μm.

[0147] In some embodiments, in step (2), the second vacuum dehydration is carried out at 120°C to 140°C; and / or, the pressure of the second vacuum dehydration is -0.100 MPa to -0.095 MPa; and / or, the second vacuum dehydration ends when the moisture content is less than or equal to 0.10%; and / or, after the vacuum dehydration ends, the temperature is lowered to 70°C to 90°C; and / or, the preheating is carried out to 70°C to 90°C; and / or, the polymerization reaction is carried out at a reaction temperature of 70°C to 90°C; and / or, the reaction time of the polymerization reaction is 1.0 to 5.0 hours; and / or, the polymerization reaction is carried out under the protection of an inert gas; and / or, after the reaction ends, the reaction system is cooled to below 70°C; and / or, the filtration by the filter is carried out through a filter screen of 2 μm to 20 μm.

[0148] In some embodiments, preferably, in step (2), the second vacuum dehydration is carried out at 125°C to 130°C.

[0149] In some embodiments, preferably, in step (2), after the vacuum dehydration ends, the temperature is lowered to 75°C to 80°C.

[0150] In some embodiments, preferably, in step (2), the preheating is carried out to 75°C to 80°C.

[0151] In some embodiments, preferably, in step (2), the polymerization reaction is carried out at a reaction temperature of 75°C to 85°C.

[0152] In some embodiments, preferably, in step (2), the reaction time of the polymerization reaction is 1.0 to 3.0 hours.

[0153] Among them, the inert gas is preferably nitrogen.

[0154] Among them, during the polymerization reaction, nitrogen is introduced and vacuum is pumped for 0.2 to 2.0 hours to remove residual bubbles.

[0155] In some embodiments, preferably, in step (2), the filtration by the filter is carried out through a filter screen of 2 μm to 10 μm.

[0156] In some embodiments, further preferably, in step (2), the filtration by the filter is carried out through a filter screen of 2 μm to 5 μm.

[0157] In some embodiments, in step (3), the mass ratio of the component A to the component B is (1.0 - 1.2):(1.0 - 1.2).

[0158] In some embodiments, preferably, in step (3), the mass ratio of the component A to the component B is 1.0:1.0.

[0159] The application of the above-mentioned bio-based polyurethane anticorrosive coating in the preparation of anticorrosive coatings and / or in the preparation of anticorrosive materials is also within the protection scope of the present invention.

[0160] Beneficial effects:

[0161] (1) The bio-based polyol used in the present invention contains rigid groups, effectively balancing the proportion of biomass materials and the crosslinking density of the coating film, and breaking through the contradiction between mechanical properties and environmental protection indicators in traditional formulations.

[0162] (2) The present invention precisely controls the moisture in the system, develops a chemical reaction model based on moisture content monitoring, and realizes precise regulation of the moisture content of raw materials through atmospheric azeotropic dehydration and vacuum dehydration, significantly inhibiting the occurrence of side reactions.

[0163] (3) The present invention constructs a multi-stage temperature control module, combined with on-line monitoring technology, to realize precise control throughout the process from raw material dehydration to polycondensation reaction, ensuring the stability and high efficiency of the production process, and significantly reducing the performance fluctuation of products.

[0164] (4) Among the three pigment fillers of wet-ground sericite mica, titanium dioxide, and barite powder in the components of the present invention, the flaky mica powder can shield ultraviolet rays and prevent moisture penetration, prevent the paint film from cracking, delay the powdering of the coating, and improve the durability and weather resistance of the coating; titanium dioxide plays a role of covering, decoloring, and protecting in the coating; barite powder has low oil absorption and has good properties such as acid resistance, alkali resistance, light resistance, heat resistance, and leveling.

[0165] (5) Due to the differences between small-scale tests and scale-up, during the scale-up process, problems such as a decrease in heat transfer efficiency and uneven mixing may be encountered, resulting in unstable product performance. Therefore, inorganic fillers are added. For example, nano-TiO2 has strong ultraviolet shielding ability and can improve the weather resistance and anti-aging properties of the coating.

[0166] (6) In the scale-up process, the scale of the reaction system increases, and it is easier for CO2 generated by the reaction of isocyanate with water to accumulate bubbles, affecting the denseness of the coating film. Calcium oxide, as a CO2 absorbent, can neutralize the CO2 generated in the reaction, reduce the generation of pores, and ensure the uniformity of the coating film and the anticorrosive performance.

[0167] (7) The present invention uses a bio - based polyol containing a benzene - ring rigid group as a raw material in combination with a preparation process, significantly improving the adhesion, salt - spray resistance, elongation at break, resistance to 5% H2SO4 immersion, and storage stability of the bio - based polyurethane anticorrosive coating; moreover, the dosage of xylene is reduced, significantly reducing the VOC content and being environmentally friendly. The combined use of a modified polymer unsaturated carboxylate dispersant (ammonium acrylate - maleic anhydride copolymer) and a fluorine - modified polyacrylate leveling agent (BYK - 380N) enables the dispersion fineness of pigments and fillers to be ≤20 μm, enhancing the shielding performance. Through a gradient dehydration process (atmospheric pre - dehydration + vacuum deep dehydration), side reactions can be inhibited, and the storage stability is improved (the viscosity increase rate drops from 45% to ≤5%).

[0168] (8) Compared with the traditional batch - type scale - up process, the process of this application can significantly improve the adhesion, salt - spray resistance, and elongation at break of the bio - based polyurethane anticorrosive coating, and significantly reduce the VOC content. Evaluated from the aspects of energy consumption and raw material utilization rate, the preparation process of this application significantly reduces the unit energy consumption and CO2 emissions, and improves the raw material utilization rate and NCO utilization rate. Detailed implementation manners

[0169] The present invention can be better understood according to the following examples. However, those skilled in the art can easily understand that the content described in the examples is only used to illustrate the present invention and should not and will not limit the present invention detailed in the claims.

[0170] In the following examples, the experimental methods are conventional methods unless otherwise specified; the reagents and materials can be obtained from commercial sources unless otherwise specified.

[0171] The bio - based polyol FHB - 275 (Zhangjiagang Feihang Technology Co., Ltd.) used in the examples of the present invention, namely the bio - based polyol FHB - 275, is a yellow liquid with a hydroxyl value of 275 ± 20 mgKOH / g, an acid value of ≤5.0 mgKOH / g, and a viscosity of 250 ± 100 cps@25°C; it is detected that the bio - based polyol FHB - 275 contains a benzene - ring structure.

[0172] The ammonium acrylate - maleic anhydride copolymer used in the examples of the present invention is prepared by stirring an acrylate - maleic anhydride copolymer with ammonia water at 30 - 40°C for 1 - 2 hours and adjusting the pH to 7.5 - 9.0 to obtain the ammonium acrylate - maleic anhydride copolymer.

[0173] Example 1:

[0174] (1) Preparation of Component A

[0175] Component A (in kg level) includes the following components in parts by weight:

[0176] Bio-based polyol: Bio-based polyol FHB-275 (Zhangjiagang Feihang Technology Co., Ltd.), 50 parts;

[0177] Pigment and filler: Wet-process sericite powder, 15 parts;

[0178] Titanium dioxide (rutile type), 8 parts;

[0179] Barite powder, 10 parts;

[0180] Plasticizer: Diisononyl phthalate (DINP), 4 parts;

[0181] Modified polymer unsaturated carboxylate dispersant: Ammonium acrylate-maleic anhydride copolymer, 3 parts;

[0182] Fluorine-modified polyacrylate leveling agent: Perfluorooctyl methacrylate-butyl acrylate copolymer (BYK-380N), 2 parts;

[0183] Defoamer (silicone-based): Polydimethylsiloxane (PDMS), 1 part;

[0184] Mixed solvent: Xylene / butyl acetate (volume ratio of xylene to butyl acetate is 3:2), 25 parts.

[0185] Preparation of Component A: Add the above-mentioned weight parts of the mixed solvent into Reactor 1, start stirring (rotation speed 500 rpm), and sequentially add the above-mentioned weight parts of the fluorine-modified polyacrylate leveling agent, plasticizer, and modified polymer unsaturated carboxylate dispersant, and mix evenly; then slowly add the above-mentioned weight parts of the bio-based polyol, stir for 10 minutes until completely dissolved, gradually heat up to 120 °C, and dehydrate under normal pressure until no water flows out; then add the above-mentioned weight parts of wet-process sericite powder, titanium dioxide, and barite powder in batches, increase the stirring speed to 1200 rpm, and continuously disperse for 40 minutes. After uniform dispersion, continuously pump the material from Reactor 1 into Reactor 2, and carry out vacuum dehydration for 30 minutes at 120 ± 3 °C and -0.095 MPa to make the moisture content ≤ 0.05%, realizing the continuous dehydration process; after dehydration, transfer the mixture to a three-roll mill and grind it to a fineness ≤ 20 μm; add the above-mentioned weight parts of the defoamer, continue stirring for 15 minutes, detect the viscosity (Coating-4 cup: 150 s) and non-volatile content (75%). After passing the inspection, package it and record it as Component A.

[0186] (2) Preparation of Component B

[0187] Component B (in kg) includes the following weight parts of components:

[0188] Polypropylene glycol ether (number average molecular weight 2000, Jiangsu Haian Petrochemical Factory), 35 parts;

[0189] Polyether glycerol (number-average molecular weight 3000, Hai'an Petrochemical Factory, Jiangsu Province), 15 parts;

[0190] Plasticizer: Diisononyl phthalate (DINP), 10 parts;

[0191] Isocyanate: Diphenylmethane diisocyanate (MDI), 8 parts;

[0192] Mixed solvent: Xylene / butyl acetate (volume ratio of xylene to butyl acetate is 3:2), 20 parts.

[0193] Preparation of Component B: Add the above-mentioned weight parts of polypropylene glycol ether, polyether glycerol and toluene to Reaction Kettle 3, heat up to 125 °C, dehydrate under reduced pressure (-0.095 MPa) for 30 minutes to make the water content ≤ 0.05%, and the residual toluene content after dehydration < 0.1%. Then cool down to 75 - 80 °C to obtain a polypropylene glycol ether / polyether glycerol mixture.

[0194] Add the above-mentioned weight parts of isocyanate and plasticizer to another Reaction Kettle 4, preheat and heat up to 75 - 80 °C in advance, and drop the obtained polypropylene glycol ether / polyether glycerol mixture into the preheated mixture of isocyanate and plasticizer through an accurate metering pump at a constant rate (20 kg / h), and finish dropping in 15 minutes; then keep warm at (80 ± 3) °C for 1.5 hours for polymerization reaction. During this period, introduce nitrogen and evacuate for 0.5 hours to remove residual bubbles; after the reaction is completed, cool down the reaction system to below 70 °C, add the above-mentioned weight parts of mixed solvent for dilution, and filter with a precision filter (5 μm filter screen, filter residue rate ≤ 0.05%) and then package to obtain Component B.

[0195] (3) Preparation of bio-based polyurethane anticorrosive coating

[0196] Mix the Component A and Component B prepared in this example online through a static mixer according to a mass ratio of 1:1 (flow matching accuracy ±2%), mix for 20 minutes until uniform, and let it stand for defoaming to obtain the bio-based polyurethane anticorrosive coating.

[0197] Example 2:

[0198] (1) Preparation of Component A

[0199] Component A (in kg level) includes the following weight parts of components:

[0200] Bio-based polyol: Bio-based polyol FHB-275 (Zhangjiagang Feihang Technology Co., Ltd.), 55 parts;

[0201] Pigment and filler: Wet ground sericite powder, 18 parts;

[0202] Titanium dioxide (rutile type), 7 parts;

[0203] Barite powder, 12 parts;

[0204] Plasticizer: Diisononyl phthalate (DINP), 5 parts;

[0205] Modified polymer unsaturated carboxylate dispersant: Ammonium acrylate-maleic anhydride copolymer, 3.5 parts;

[0206] Fluorine-modified polyacrylate leveling agent: Perfluorooctyl methacrylate-butyl acrylate copolymer (BYK-380N), 1.5 parts;

[0207] Defoamer (silicone-based): Polydimethylsiloxane (PDMS), 0.8 part;

[0208] Mixed solvent: Xylene / butyl acetate (volume ratio of xylene to butyl acetate is 4:1), 28 parts.

[0209] Preparation of Component A: Add the above-mentioned weight parts of the mixed solvent into Reactor 1, start stirring (rotation speed 600 rpm), and sequentially add the above-mentioned weight parts of the fluorine-modified polyacrylate leveling agent, plasticizer, and modified polymer unsaturated carboxylate dispersant, and mix evenly; then slowly add the above-mentioned weight parts of the bio-based polyol, stir for 15 minutes until completely dissolved, gradually heat up to 120 °C, and dehydrate under normal pressure until no water flows out; then add the above-mentioned weight parts of wet sericite powder, titanium dioxide, and barite powder in batches, increase the stirring speed to 1500 rpm, and continuously disperse for 45 minutes. After uniform dispersion, continuously pump the material from Reactor 1 into Reactor 2, and carry out vacuum dehydration at 120 ± 3 °C and -0.095 MPa for 30 minutes to make the water content ≤ 0.05%, realizing the continuous dehydration process; after dehydration, transfer the mixture to a three-roll mill and grind it to a fineness ≤ 15 μm, add the above-mentioned weight parts of the defoamer, and continue stirring for 20 minutes. Detect the viscosity (Coating-4 cup: 140 s) and non-volatile content (76%). After passing the inspection, package it and label it as Component A.

[0210] (2) Preparation of Component B

[0211] Component B (in kg) includes the following components in weight parts:

[0212] Polypropylene glycol ether (number average molecular weight 2500, Hai'an Petrochemical Factory, Jiangsu Province), 40 parts;

[0213] Polyether glycerol (number average molecular weight 3500, Hai'an Petrochemical Factory, Jiangsu Province), 18 parts;

[0214] Plasticizer: Diisononyl phthalate (DINP), 12 parts;

[0215] Isocyanate: Diphenylmethane diisocyanate (MDI), 9 parts;

[0216] Mixed solvent: Xylene / butyl acetate (volume ratio of xylene to butyl acetate is 4:1), 22 parts.

[0217] Preparation of Component B: Add the above-mentioned weight parts of polypropylene glycol ether, polyether glycerol and toluene to Reaction Kettle 3, heat up to 130 °C, and dehydrate under reduced pressure (-0.1 MPa) for 30 minutes to make the water content ≤ 0.04%, and the residual toluene content after dehydration < 0.1%. Then cool down to 75 - 80 °C to obtain a polypropylene glycol ether / polyether glycerol mixture.

[0218] Add the above-mentioned weight parts of isocyanate and plasticizer to another Reaction Kettle 4, preheat and heat up to 75 - 80 °C in advance. Drop the obtained polypropylene glycol ether / polyether glycerol mixture into the preheated mixture of isocyanate and plasticizer through an accurate metering pump at a constant rate (20 kg / h), and finish dropping in 15 minutes; then heat up to (80 ± 3) °C and keep warm for 1.5 hours for polymerization reaction. During this period, introduce nitrogen and evacuate for 0.5 hours to remove residual bubbles; after the reaction ends, cool down the reaction system to below 70 °C, add the above-mentioned weight parts of mixed solvent for dilution, and filter with a precision filter (3 μm filter screen, residue rate ≤ 0.05%) and then package to obtain Component B.

[0219] (3) Preparation of bio-based polyurethane anticorrosive coating

[0220] Mix the Component A and Component B prepared in this example online through a static mixer according to a mass ratio of 1:1 (flow matching accuracy ±2%), mix for 15 minutes until uniform, and let it stand to defoam to obtain the bio-based polyurethane anticorrosive coating.

[0221] Example 3:

[0222] (1) Preparation of Component A

[0223] Component A (in kg level) includes the following components in weight parts:

[0224] Bio-based polyol: Bio-based polyol FHB-275 (Zhangjiagang Feihang Technology Co., Ltd.), 45 parts;

[0225] Pigment and filler: Wet-process sericite powder, 20 parts;

[0226] Titanium dioxide (rutile type), 6 parts;

[0227] Barite powder, 9 parts;

[0228] Plasticizer: Diisononyl phthalate (DINP), 6 parts;

[0229] Modified polymer unsaturated carboxylate dispersant: Ammonium salt of acrylic acid - maleic anhydride copolymer, 4 parts;

[0230] Fluorine - modified polyacrylate leveling agent: Copolymer of perfluorooctyl methacrylate - butyl acrylate (BYK - 380N), 1.2 parts;

[0231] Defoaming agent (silicone - based): Polydimethylsiloxane (PDMS), 0.6 parts;

[0232] Mixed solvent: Ethyl acetate / propylene glycol methyl ether (volume ratio of ethyl acetate to propylene glycol methyl ether is 2:1), 30 parts.

[0233] Preparation of Component A: Add the above - mentioned weight parts of the mixed solvent into Reactor 1, start stirring (rotation speed 550 rpm), and sequentially add the above - mentioned weight parts of the fluorine - modified polyacrylate leveling agent, plasticizer, and modified polymer unsaturated carboxylate dispersant, and mix evenly; then slowly add the above - mentioned weight parts of the bio - based polyol, stir for 12 minutes until completely dissolved, gradually heat up to 120 °C, and dehydrate under normal pressure until no water flows out; then add the above - mentioned weight parts of wet - process sericite powder, titanium dioxide, and barite powder in batches, increase the stirring speed to 1300 rpm, and continuously disperse for 50 minutes. After dispersion is uniform, continuously pump the material from Reactor 1 into Reactor 2, and carry out vacuum dehydration for 30 minutes at 120 ± 3 °C and - 0.095 MPa to make the moisture content ≤ 0.05%, realizing the continuous dehydration process; after dehydration, transfer the mixture to a three - roll mill and grind it to a fineness ≤ 18 μm; add the above - mentioned weight parts of the defoaming agent, continue stirring for 18 minutes, detect the viscosity (Coating - 4 cup: 130 s) and non - volatile content (78%), and after passing the inspection, package it, denoted as Component A.

[0234] (2) Preparation of Component B

[0235] Component B (in kg) includes the following components in weight parts:

[0236] Polypropylene glycol ether (number - average molecular weight 2200, Hai'an Petrochemical Factory, Jiangsu Province), 38 parts;

[0237] Polyether glycerol (number - average molecular weight 2800, Hai'an Petrochemical Factory, Jiangsu Province), 20 parts;

[0238] Plasticizer: Di - isononyl phthalate (DINP), 14 parts;

[0239] Isocyanate: Isophorone diisocyanate (IPDI), 8 parts;

[0240] Mixed solvent: Ethyl acetate / propylene glycol methyl ether (volume ratio of ethyl acetate to propylene glycol methyl ether is 2:1), 18 parts.

[0241] Preparation of Component B: Add the above-mentioned parts by weight of polypropylene glycol ether, polyether glycerol and toluene into reaction kettle 3, heat up to 128 °C, and dehydrate under reduced pressure (-0.098 MPa) for 30 minutes to make the water content ≤ 0.03%, and the residual toluene content after dehydration < 0.1%. Then cool down to 75 - 80 °C to obtain a polypropylene glycol ether / polyether glycerol mixture.

[0242] Add the above-mentioned parts by weight of isocyanate and plasticizer into another reaction kettle 4, preheat and heat up to 75 - 80 °C in advance, and dropwise add the obtained polypropylene glycol ether / polyether glycerol mixture into the preheated mixture of isocyanate and plasticizer through an accurate metering pump at a constant rate (20 kg / h), and finish dropping in 15 minutes; then heat up to (80 ± 3) °C and keep warm for 1.5 hours for polymerization reaction. During this period, introduce nitrogen and evacuate for 0.5 hours to remove residual bubbles; after the reaction is completed, cool down the reaction system to below 70 °C, add the above-mentioned parts by weight of mixed solvent for dilution, filter with a precision filter (5 μm filter screen, filter residue rate ≤ 0.05%), and then package to obtain Component B.

[0243] (3) Preparation of Bio-based Polyurethane Anticorrosive Coating

[0244] Mix the Component A and Component B prepared in this example online through a static mixer according to a mass ratio of 1:1 (flow matching accuracy ±2%), mix for 18 minutes until uniform, and then stand for defoaming to obtain the bio-based polyurethane anticorrosive coating.

[0245] Example 4: Process Scale-up Based on Example 1

[0246] (1) Preparation of Component A

[0247] Component A (total tonnage batch) includes the following parts by weight of components:

[0248] Bio-based polyol: Bio-based polyol FHB-275 (Zhangjiagang Feihang Technology Co., Ltd.), 500 kg;

[0249] Pigment and filler: Wet-process sericite powder, 150 kg;

[0250] Titanium dioxide (rutile type), 80 kg;

[0251] Barite powder, 100 kg;

[0252] Plasticizer: Diisononyl phthalate (DINP), 40 kg;

[0253] Modified polymer unsaturated carboxylate dispersant: Ammonium acrylate-maleic anhydride copolymer, 30 kg;

[0254] Fluorine-modified polyacrylate leveling agent: Perfluorooctyl methacrylate-butyl acrylate copolymer (BYK-380N), 20 kg;

[0255] Defoamer (silicone-based): Polydimethylsiloxane (PDMS), 10 kg;

[0256] Mixed solvent: Xylene / butyl acetate (volume ratio of xylene to butyl acetate is 3:2), 250 kg;

[0257] Inorganic nano filler: Nano-TiO2 (Maclean), 12 kg;

[0258] CO2 absorbent: Calcium oxide (Xinhengyan), 3 kg.

[0259] The preparation of component A includes the following steps:

[0260] (a) Premixing of raw materials: In reactor 1, successively add the above-mentioned parts by weight of the mixed solvent, fluorine-modified polyacrylate leveling agent, plasticizer, and modified polymer unsaturated carboxylate dispersant, start high-speed stirring (600 rpm) and mix for 10 minutes until evenly mixed;

[0261] (b) Dispersion of polyol: Subsequently, slowly add the above-mentioned parts by weight of the bio-based polyol to the mixture obtained in step (a), stir for 15 minutes until completely dissolved, gradually heat up to 120 °C, and dehydrate under normal pressure until no water flows out;

[0262] (c) Dispersion of pigments and fillers: Then, continue to add the above-mentioned parts by weight of wet-ground sericite powder, titanium dioxide, and barite powder to the mixture obtained in step (b) in batches, increase the stirring speed to 1500 rpm, and continuously disperse for 50 minutes;

[0263] (d) Nano material strengthening: Continue to add nano-TiO2 and CO2 absorbent to the mixture obtained in step (c), and continue to disperse for 20 minutes;

[0264] (e) Vacuum dehydration: Using a series of reactors, transfer the mixture obtained in step (d) to reactor 2, and carry out vacuum dehydration at 120 ± 3 °C and -0.095 MPa for 120 minutes to make the moisture content ≤ 0.05% (initial moisture content 0.25%), realizing the continuous dehydration process; The purpose of dehydration in this step: Control the moisture content in the raw materials to avoid side reactions between the residual moisture in the polyether polyol and the isocyanate (such as generating urea or carbon dioxide, resulting in bubbles or reducing the crosslinking density), and at the same time improve the storage stability of the coating (prevent the viscosity from increasing significantly during storage);

[0265] (f) Grinding and Packaging: Grind the mixture obtained in step (e) with a three-roll mill to a fineness of ≤20 μm, add the defoamer in the above weight parts, continue stirring for 20 minutes, and then monitor the following indicators in real time through an on-line detection system: Viscosity: (Coating - 4 cup: 145 s) and non-volatile content (77%). After passing the inspection, conduct on-line filling, which is recorded as Component A.

[0266] (2) Preparation of Component B

[0267] Component B (total tonnage batch) includes the following components in weight parts:

[0268] Polypropylene glycol ether (number average molecular weight 2000, Hai'an Petrochemical Factory, Jiangsu Province), 350 kg;

[0269] Polyether glycerol (number average molecular weight 3000, Hai'an Petrochemical Factory, Jiangsu Province), 150 kg;

[0270] Plasticizer: Diisononyl phthalate (DINP), 100 kg;

[0271] Isocyanate: Diphenylmethane diisocyanate (MDI), 80 kg;

[0272] Mixed solvent: Xylene / butyl acetate (volume ratio of xylene to butyl acetate is 3:2), 200 kg.

[0273] Preparation of Component B:

[0274] (i) Polyether dehydration: In reaction kettle 3, mix the above weight parts of polypropylene glycol ether, polyether glycerol with toluene, heat up to 125 °C, and dehydrate under reduced pressure (-0.095 MPa) for 80 minutes to make the water content <0.05% and the toluene residue content <0.1% after dehydration. Then cool the temperature to 75 - 80 °C to obtain a polypropylene glycol ether / polyether glycerol mixture;

[0275] (ii) Polymerization reaction: Add the above weight parts of isocyanate and plasticizer to another reaction kettle 4, preheat and heat up to 75 - 80 °C in advance, and drop the polypropylene glycol ether / polyether glycerol mixture obtained in step (i) into the preheated mixture of isocyanate and plasticizer through an accurate metering pump at a constant rate (20 kg / h). Finish dropping in 1 hour; then keep the temperature at (80 ± 3) °C for 3 hours for polymerization reaction, and pass nitrogen and evacuate for 0.5 hour during the process to remove bubbles;

[0276] (iii) Dilution and filtration: After the reaction is completed, cool the reaction system to below 70 °C, add the above weight parts of mixed solvent for dilution, and continuously discharge through a 5 μm precision filter (filter residue rate ≤0.05%) to obtain Component B.

[0277] (3) Preparation of Bio-based Polyurethane Anticorrosive Coating

[0278] Mix the component A and component B prepared in this example online through a static mixer at a mass ratio of 1:1 (flow matching accuracy ±2%), mix for 15 minutes until uniform, let stand for defoaming, and then directly fill online to obtain the bio-based polyurethane anticorrosive coating.

[0279] Comparative Example 1: Existing formula and preparation process of bio-based polyurethane anticorrosive coating

[0280] This comparative example is the comparative example of Example 1.

[0281] (1) Preparation of component A

[0282] Component A (in kg) includes the following components in parts by weight:

[0283] Bio-based polyol: Bio-based polyol (without aromatic group structure, commercially available general type, purchased from BASF, model, Lupranol BALANCE 50, bio-carbon content 30%), 50 parts;

[0284] Pigment and filler: Wet ground sericite powder, 15 parts;

[0285] Titanium dioxide (rutile type), 8 parts;

[0286] Barite powder, 10 parts;

[0287] Plasticizer: Diisononyl phthalate (DINP), 4 parts;

[0288] Modified polymer unsaturated carboxylate dispersant: Ammonium acrylate-maleic anhydride copolymer, 3 parts;

[0289] Defoamer (silicone type): Polydimethylsiloxane (PDMS), 1 part;

[0290] Mixed solvent: Xylene / butyl acetate (volume ratio of xylene to butyl acetate is 3:1), 25 parts.

[0291] Preparation of Component A: Add the above-mentioned parts by weight of the mixed solvent into Reactor 1, start stirring (rotation speed: 500 rpm), and sequentially add the above-mentioned parts by weight of the plasticizer and the modified polymer unsaturated carboxylate dispersant, and mix evenly; then slowly add the above-mentioned parts by weight of the bio-based polyol and stir for 10 minutes until completely dissolved; then add the above-mentioned parts by weight of the wet sericite powder, titanium dioxide powder, and barite powder in batches, increase the stirring speed to 1200 rpm, and continue to disperse for 40 minutes. After uniform dispersion, heat to 120 ± 3 °C under normal pressure for dehydration for 2 hours, with a moisture content of 0.08%; after dehydration, transfer the mixture to a three-roll grinder and grind it to a fineness of ≤ 20 μm; add the above-mentioned parts by weight of the defoaming agent, continue to stir for 15 minutes, detect the viscosity (Coating-4 cup: 200 s) and non-volatile content (70%). After passing the inspection, it is packaged and recorded as Component A.

[0292] (2) Preparation of Component B

[0293] Component B (in kg) includes the following parts by weight of components:

[0294] Polypropylene glycol ether (number average molecular weight 2000, Haian Petrochemical Factory, Jiangsu Province), 35 parts;

[0295] Polyether glycerol (number average molecular weight 3000, Haian Petrochemical Factory, Jiangsu Province), 15 parts;

[0296] Plasticizer: Diisononyl phthalate (DINP), 10 parts;

[0297] Isocyanate: Diphenylmethane diisocyanate (MDI), 8 parts;

[0298] Mixed solvent: Xylene / butyl acetate (volume ratio of xylene to butyl acetate is 3:2), 20 parts.

[0299] Preparation of Component B: Add the above-mentioned parts by weight of polypropylene glycol ether, polyether glycerol and toluene into Reactor 2, heat up to 125 °C, dehydrate under normal pressure for 1 hour, with a moisture content of 0.10% and a residual toluene content of 12%, and then cool down to 75 - 80 °C to obtain a polypropylene glycol ether / polyether glycerol mixture.

[0300] In another reactor 3, the above-mentioned parts by weight of isocyanate and plasticizer are added, preheated and heated up to 75-80°C in advance. The obtained polypropylene glycol ether / polyether glycerol mixture is added dropwise to the preheated mixture of isocyanate and plasticizer through an accurate metering pump at a constant rate (20 kg / h), and the dropping is completed in 15 minutes. Subsequently, it is kept warm at (80±3)°C for 1.5 hours for polymerization reaction. During this period, nitrogen is introduced and vacuum is pumped for 0.5 hour to remove residual bubbles. After the reaction is completed, the reaction system is cooled to below 70°C, diluted with the above-mentioned parts by weight of mixed solvent, filtered (5μm filter screen) and then packaged to obtain Component B.

[0301] (3) Preparation of bio-based polyurethane anticorrosive coating

[0302] The Component A and Component B prepared in this example are mixed online through a static mixer according to a mass ratio of 1:1 (flow matching accuracy ±2%), mixed for 20 minutes until uniform, and then left to stand for defoaming to obtain the bio-based polyurethane anticorrosive coating.

[0303] Comparative Example 2: Traditional batchwise scale-up process

[0304] This comparative example is the comparative example of Example 4.

[0305] (1) Preparation of Component A

[0306] Component A (total tonnage batch) includes the following parts by weight of components:

[0307] Bio-based polyol: Bio-based polyol FHB-275 (Zhangjiagang Feihang Technology Co., Ltd.), 500 kg;

[0308] Pigment and filler: Wet ground sericite powder, 150 kg;

[0309] Titanium dioxide (rutile type), 80 kg;

[0310] Barite powder, 100 kg;

[0311] Plasticizer: Diisononyl phthalate (DINP), 40 kg;

[0312] Modified polymer unsaturated carboxylate dispersant: Ammonium acrylate-maleic anhydride copolymer, 30 kg;

[0313] Fluorine-modified polyacrylate leveling agent: Perfluorooctyl methacrylate-butyl acrylate copolymer (BYK-380N), 20 kg;

[0314] Defoamer (silicone-based): Polydimethylsiloxane (PDMS), 10 kg;

[0315] Mixed solvent: xylene / butyl acetate (volume ratio of xylene to butyl acetate is 3:2), 250 kg;

[0316] Inorganic nano filler: nano-TiO₂ (Maclean), 12 kg;

[0317] CO₂ absorbent: calcium oxide (Xinhengyan), 3 kg.

[0318] The preparation of component A includes the following steps:

[0319] (a) Premixing of raw materials: In reactor 1, add the above-mentioned parts by weight of the mixed solvent, fluorine-modified polyacrylate leveling agent, plasticizer, and modified polymer unsaturated carboxylate dispersant in sequence, start high-speed stirring (600 rpm) and mix for 10 minutes until evenly mixed;

[0320] (b) Dispersion of polyol: Subsequently, slowly add the above-mentioned parts by weight of the bio-based polyol to the mixture obtained in step (a), and stir for 15 minutes until completely dissolved;

[0321] (c) Dispersion of pigments and fillers: Then, continue to add the above-mentioned parts by weight of wet-ground sericite powder, titanium dioxide, and barite powder to the mixture obtained in step (b) in batches, increase the stirring speed to 1500 rpm, and continuously disperse for 50 minutes;

[0322] (d) Strengthening with nano materials: Continue to add nano-TiO₂ and CO₂ absorbent to the mixture obtained in step (c), and continue to disperse for 20 minutes;

[0323] (e) Atmospheric dehydration: Dehydrate the mixture obtained in step (d) at 120 ± 3 °C under atmospheric pressure for 2 hours, and the water content is reduced to 0.08% (initial water content 0.25%);

[0324] (f) Grinding and packaging: Grind the mixture obtained in step (e) with a three-roll mill to a fineness of ≤ 20 μm, add the above-mentioned parts by weight of defoamer, continue to stir for 20 minutes, and then monitor the following indicators in real time through an on-line detection system: viscosity (coat-4 cup: 200 s) and non-volatile content (60%). After passing the inspection, carry out on-line filling, which is recorded as component A.

[0325] (2) Preparation of component B

[0326] Component B (total batch quantity in tons) includes the following components in parts by weight:

[0327] Polypropylene glycol ether (number average molecular weight 2000, Jiangsu Haian Petrochemical Factory), 350 kg;

[0328] Polyether glycerol (number average molecular weight 3000, Jiangsu Haian Petrochemical Factory), 150 kg;

[0329] Plasticizer: Diisononyl phthalate (DINP), 100 kg;

[0330] Isocyanate: Diphenylmethane diisocyanate (MDI), 80 kg;

[0331] Mixed solvent: Xylene / butyl acetate (volume ratio of xylene to butyl acetate is 3:2), 200 kg.

[0332] Preparation of Component B:

[0333] (i) Polyether dehydration: In reaction kettle 2, mix the above-mentioned parts by weight of polypropylene glycol ether, polyether glycerol and toluene, heat it to 125 °C under normal pressure, dehydrate for 1 hour under normal pressure, with a water content of 0.12% and a toluene residue of 18%. Then cool the temperature to 75 - 80 °C to obtain a polypropylene glycol ether / polyether glycerol mixture;

[0334] (ii) Polymerization reaction: Add the above-mentioned parts by weight of isocyanate and plasticizer to another reaction kettle 3, preheat and raise the temperature to 75 - 80 °C in advance. Drop the polypropylene glycol ether / polyether glycerol mixture obtained in step (i) into the preheated mixture of isocyanate and plasticizer through an accurate metering pump at a constant rate (20 kg / h), and finish dropping in 1 hour. Then keep it warm at (80 ± 3) °C for 3 hours for polymerization reaction, and pass nitrogen and evacuate to remove bubbles for 0.5 hour during this period;

[0335] (iii) Dilution and filtration: After the reaction is completed, cool the reaction system to below 70 °C, add the above-mentioned parts by weight of mixed solvent for dilution, filter through a 200-mesh filter screen, with a residue rate of 2.3%, and continuously discharge to obtain Component B.

[0336] (3) Preparation of bio-based polyurethane anticorrosive coating

[0337] Mix the Component A and Component B prepared in this example according to a mass ratio of 1:1, stir with an anchor stirrer (500 rpm) for 15 minutes until uniform, stand for defoaming, and then directly fill online to obtain the bio-based polyurethane anticorrosive coating.

[0338] Example 5: Performance test of bio-based polyurethane anticorrosive coating

[0339] The performance tests were carried out on the bio-based polyurethane anticorrosive coatings prepared in Examples 1 to 4 and Comparative Examples 1 to 2 (adhesion: GB / T 5210-2006; salt spray resistance: GB / T 10125-2021; VOC content: GB / T23986-2009; elongation at break: GB / T 1040.3-2006; immersion in 5% H2SO4: GB / T 9274-1988; storage stability: GB / T6753.3-1986; NCO utilization rate, the content change of isocyanate groups (-NCO) before and after the reaction was determined by chemical analysis (titration method); raw material utilization rate = the amount of raw materials actually used in the reaction ÷ total feed amount × 100%; unit energy consumption (kWh / ton) = total power consumption (kWh) ÷ production volume (ton); CO2 emission (energy) = energy consumption (kWh / ton) × carbon emission coefficient (ton CO2 / kWh)). The specific results are shown in Table 1, Table 2 and Table 3.

[0340] Table 1

[0341]

[0342] As can be seen from Table 1, using bio-based polyols containing benzene ring rigid groups as raw materials can improve the adhesion, salt spray resistance, elongation at break, immersion in 5% H2SO4 and storage stability of bio-based polyurethane anticorrosive coatings; and the amount of xylene used is reduced, significantly reducing the VOC content and being environmentally friendly. In Example 1, a modified polymer unsaturated carboxylate dispersant (ammonium acrylate-maleic anhydride copolymer) and a fluorine-modified polyacrylate leveling agent (BYK-380N) were used in combination, and the dispersion fineness of pigments and fillers was ≤20 μm, improving the shielding performance. In Example 1, through the gradient dehydration process (atmospheric pressure pre-dehydration + vacuum deep dehydration), side reactions can be inhibited and the storage stability is improved (the viscosity increase rate is reduced from 45% to ≤5%).

[0343] Table 2

[0344] Performance indicators Example 4 Comparative Example 2 Improvement effect Adhesion (MPa) 8.9 5.2 ↑71.2％ Salt spray resistance (h) 3100 1800 ↑72.2％ VOC content (g / L) 175 300 ↓41.7％ Elongation at break (%) 425 280 ↑51.8％ Unit energy consumption (kWh / ton) 75 220 ↓65.9％ <![CDATA[CO2 emissions (tons per ton of coating)]]> 1.7 tons / ton 3.5 tons / ton ↓51.4％ Raw material utilization rate (%) 2.3 0.05 ↑98％ NCO utilization rate (%) 98 78 ↑25.6％

[0345] As can be seen from Table 2, compared with Comparative Example 2 of the traditional batch amplification process, the process of this application can significantly improve the adhesion, salt spray resistance and elongation at break of the bio-based polyurethane anticorrosive coating, and significantly reduce the VOC content. Evaluated from energy consumption and raw material utilization rate, the preparation process of this application significantly reduces the unit energy consumption and CO2 emission, and improves the raw material utilization rate and NCO utilization rate.

[0346] Performance assessment of the bio-based polyurethane anticorrosive coating prepared in Example 4 in Table 3

[0347]

[0348]

[0349] The present invention provides an idea and method for a bio-based polyurethane anticorrosive coating, its preparation method and application. There are many ways to specifically implement this technical solution. The above description is only a preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention. Each component not clearly defined in this embodiment can be implemented by existing technologies.

Claims

1. A bio-based polyurethane anti-corrosion coating, characterized in that: The bio-based polyurethane anti-corrosion coating comprises component A and component B; Wherein, component A comprises the following components in parts by weight: Bio-based polyols, 45.0-55.0 parts; Pigments and fillers, 32.0-38.0 parts; The first plasticizer, 4.0 to 8.0 parts; Modified polymer unsaturated carboxylate dispersant, 3.0-6.0 parts; Fluorine-modified polyacrylate leveling agent, 1.0-4.0 parts; Defoaming agent, 0.6-1.5 parts; The first mixed solvent, 25.0 to 30.0 parts; Wherein, component B comprises the following components in parts by weight: Polypropylene glycol ether, 30.0-40.0 parts; Polyether propylene glycol, 15.0-25.0 parts; Second plasticizer, 8.0-15.0 parts; Diisocyanate, 8.0-12.0 parts; The second mixed solvent, 15.0 to 25.0 parts; Wherein, the mass ratio of component A to component B is (1.0-1.2): (1.0-1.2).

2. The bio-based polyurethane anti-corrosion coating according to claim 1, characterized in that: The bio-based polyurethane anti-corrosion coating comprises component A and component B; Wherein, component A comprises the following components in parts by weight: Bio-based polyols, 45.0-55.0 parts; Pigments and fillers, 33.0-37.0 parts; The first plasticizer, 4.0 to 6.0 parts; Modified polymer unsaturated carboxylate dispersant, 3.0-4.0 parts; Fluorine-modified polyacrylate leveling agent, 1.0-2.0 parts; Defoaming agent, 0.6-1.0 part; The first mixed solvent, 25.0 to 30.0 parts; Wherein, component B comprises the following components in parts by weight: Polypropylene glycol ether, 35.0-40.0 parts; Polyether propylene glycol, 15.0-20.0 parts; The second plasticizer, 10.0 to 14.0 parts; Diisocyanate, 8.0-9.0 parts; The second mixed solvent, 18.0 to 22.0 parts; Wherein, the mass ratio of component A to component B is 1.0:1.

0.

3. The bio-based polyurethane anti-corrosion coating according to claim 1 or 2, characterized in that: The bio-based polyol is bio-based polyol FHB-275; and / or, the pigment filler is any one or a combination of wet-process sericite powder, rutile titanium dioxide, barite powder, talcum powder, zinc phosphate, aluminum tripolyphosphate and mica iron oxide; and / or, the first plasticizer is any one or a combination of diisononyl phthalate, dioctyl terephthalate, dioctyl adipate and polypropylene adipate; the modified polymer unsaturated carboxylate dispersant is acrylic acid-maleic anhydride copolymer Any one or a combination of ammonium salt, sodium salt of acrylic acid-maleic anhydride copolymer, sodium dodecylbenzene sulfonate, acrylic acid copolymer and polyurethane modified polymer dispersant BYK-190; and / or, the fluorine-modified polyacrylate leveling agent is any one or a combination of perfluorooctyl methacrylate-butyl acrylate copolymer BYK-380N, acrylate copolymer BYK-358N, polyether modified polydimethylsiloxane BYK-333 and acrylate dispersant BYK-154; And / or, the defoamer is any one of polydimethylsiloxane, polyether-modified siloxane BYK-088 and polyether defoamer BYK-1799, or a combination of several thereof; and / or, the first mixed solvent is any one of a mixture of xylene and butyl acetate in any proportion, a mixture of ethyl acetate and propylene glycol methyl ether in any proportion, a mixture of ethanol and acetone in any proportion, and a mixture of ethyl acetoacetate and dipropylene glycol methyl ether in any proportion, or a combination of several thereof; and / or, the second plasticizer is phthalate The invention relates to a method for preparing the present invention wherein the first solvent is selected from the group consisting of diisononyl terephthalate, dioctyl terephthalate, dioctyl adipate and polypropylene adipate, or a combination of any one of diisononyl terephthalate, dioctyl terephthalate, dioctyl adipate and polypropylene adipate; and / or the diisocyanate is diphenylmethane diisocyanate or isophorone diisocyanate; and / or the second mixed solvent is any one of a mixture of xylene and butyl acetate in any proportion, a mixture of ethyl acetate and propylene glycol methyl ether in any proportion, a mixture of ethanol and acetone in any proportion, and a mixture of ethyl acetoacetate and dipropylene glycol methyl ether in any proportion, or a combination of any one of the above.

4. The bio-based polyurethane anti-corrosion coating according to claim 1 or 2, characterized in that: Component A of the bio-based polyurethane anti-corrosion coating also includes inorganic nanofillers and CO2 absorbents; Wherein, component A comprises the following components in parts by weight: Bio-based polyols, 45.0-55.0 parts; Pigments and fillers, 32.0-38.0 parts; The first plasticizer, 4.0 to 8.0 parts; Modified polymer unsaturated carboxylate dispersant, 3.0-6.0 parts; Fluorine-modified polyacrylate leveling agent, 1.0-4.0 parts; Defoaming agent, 0.6-1.5 parts; The first mixed solvent, 25.0 to 30.0 parts; Inorganic nanofiller, 1.0-1.2 parts; CO2 absorbent, 0.3-0.5 parts; Preferably, Component A includes the following components in parts by weight: Bio-based polyols, 45.0-55.0 parts; Pigments and fillers, 33.0-37.0 parts; The first plasticizer, 4.0 to 6.0 parts; Modified polymer unsaturated carboxylate dispersant, 3.0-4.0 parts; Fluorine-modified polyacrylate leveling agent, 1.0-2.0 parts; Defoaming agent, 0.6-1.0 part; The first mixed solvent, 25.0 to 30.0 parts; Inorganic nanofiller, 1.2 parts; CO2 absorbent, 0.3 parts; And / or, when component A of the bio-based polyurethane anti-corrosion coating also includes inorganic nanofillers and CO2 absorbents, the inorganic nanofillers are any one or a combination of nano-silicon dioxide, nano-titanium dioxide, nano-aluminum oxide, nano-zinc oxide and nano-ferric oxide, and the CO2 absorbent is any one or a combination of calcium oxide, calcium hydroxide, potassium carbonate and sodium hydroxide.

5. The method for preparing the bio-based polyurethane anticorrosive coating according to any one of claims 1 to 4, characterized in that: The steps include: (1) Add the first mixed solvent, fluorine-modified polyacrylate leveling agent, first plasticizer, and modified polymer unsaturated carboxylate dispersant in the first reaction kettle in the weight proportions of any one of claims 1 to 4 and mix them evenly; then add the bio-based polyol in the weight proportions, mix evenly, and perform normal pressure dehydration; then add the pigment and filler in the weight proportions, mix evenly; then pump the reaction material into the second reaction kettle for the first reduced pressure dehydration; after the dehydration is completed, transfer the reaction mixture to a grinder for grinding; finally, add the defoamer in the weight proportions, mix evenly, and obtain component A; (2) adding the polypropylene glycol ether, polyether glycerol and toluene in the weight proportions of any one of claims 1 to 4 into a third reaction kettle, performing a second reduced pressure dehydration, and cooling the reaction kettle after the reduced pressure dehydration to obtain a polypropylene glycol ether / polyether glycerol mixture; preheating the diisocyanate and the second plasticizer in the weight proportions in a fourth reaction kettle to obtain a diisocyanate / second plasticizer mixture; mixing the polypropylene glycol ether / polyether glycerol mixture and the diisocyanate / second plasticizer mixture to perform a polymerization reaction; after the reaction is completed, cooling the reaction system, adding the second mixed solvent in the weight proportions to dilute, filtering, and discharging the material to obtain component B; (3) Component A and component B are mixed evenly in a static mixer, and allowed to stand for defoaming to obtain a bio-based polyurethane anti-corrosion coating.

6. The preparation method according to claim 5, characterized in that: In step (1), the atmospheric pressure dehydration is carried out at 105-125°C; and / or, the first reduced pressure dehydration is carried out at 110-130°C; and / or, the first reduced pressure dehydration has a pressure of -0.095MPa to -0.090MPa; and / or, the first reduced pressure dehydration is carried out until the moisture content is less than or equal to 0.10% to terminate the dehydration; and / or, the grinding grinds the material to a particle size less than or equal to 30μm.

7. The preparation method according to claim 5, characterized in that: In step (2), the second decompression dehydration is carried out at 120°C to 140°C; and / or, the second decompression dehydration is carried out at a pressure of -0.100MPa to -0.095MPa; and / or, the second decompression dehydration is carried out until the water content is less than or equal to 0.10% to terminate the dehydration; and / or, after the decompression dehydration is completed, the temperature is lowered to 70°C to 90°C; and / or, the preheating is carried out to 70°C to 90°C; and / or, the polymerization reaction is carried out at a reaction temperature of 70°C to 90°C; and / or, the polymerization reaction is carried out for a reaction time of 1.0 to 5.0 hours; and / or, the polymerization reaction is carried out under the protection of an inert gas; and / or, after the reaction is completed, the reaction system is cooled to below 70°C; and / or, the filter is filtered through a 2μm to 20μm filter.

8. The preparation method according to claim 5, characterized in that: In step (1), when the component A further includes an inorganic nanofiller and a CO2 absorbent, the component A is prepared according to the following method: Add the first mixed solvent, fluorine-modified polyacrylate leveling agent, first plasticizer and modified polymer unsaturated carboxylate dispersant in the weight proportions of any one of claims 1 to 4 into the first reaction kettle and mix them evenly; then add the bio-based polyol in the weight proportions, mix evenly and dehydrate at normal pressure; then add the pigment and filler in the weight proportions and mix evenly; continue to add the inorganic nanofiller and CO2 absorbent in the weight proportions and mix evenly; then pump the reaction materials into the second reaction kettle for the first reduced pressure dehydration; after the dehydration is completed, transfer the reaction mixture to a grinder for grinding; finally, add the defoaming agent in the weight proportions and mix evenly to obtain component A.

9. The preparation method according to claim 5, characterized in that: In step (3), the mass ratio of component A to component B is (1.0-1.2): (1.0-1.2).

10. Use of the bio-based polyurethane anti-corrosion coating according to any one of claims 1 to 4 in the preparation of anti-corrosion coatings and / or in the preparation of anti-corrosion materials.

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