A vegetable oil based polyurethane anticorrosive coating

Abstract

The application discloses a plant oil-based polyurethane anticorrosive paint, relates to the technical field of anticorrosive paint, and comprises a primer, an intermediate paint and a topcoat, and is prepared from modified plant oil polyol, isocyanate, a catalyst, pigments, a colorant, a filler, an anti-settling agent and a mixed solvent as raw materials. The plant oil-based polyurethane anticorrosive paint has the advantages of simple preparation process and easy operation; the traditional petrochemical-based polyol is replaced by the plant oil polyol, the use of the non-renewable petrochemical-based polyol is avoided, the plant oil-based polyurethane anticorrosive paint is green and environment-friendly, and the cost is reduced. Meanwhile, the prepared plant oil-based polyurethane anticorrosive primer, intermediate paint and topcoat are used in a matched mode, can be widely applied to the anticorrosive scenes in the industrial fields such as steel structures, process pipelines, storage tanks and ladder platforms, can replace the petrochemical-based zinc-rich epoxy primer, the epoxy micaceous iron intermediate paint and the polyurethane / acrylate topcoat, has excellent acid and alkali resistance and salt mist resistance, the adhesion is increased by more than 2.5 times, the VOC content is reduced by more than 50%, and the biological carbon content is more than 30%.

Description

Technical Field

[0001] This invention relates to the field of anti-corrosion coating technology, specifically to a plant oil-based polyurethane anti-corrosion coating. Background Technology

[0002] Polyurethane is a multifunctional polymer material obtained by the polymerization addition reaction of polyols and isocyanates. It is hailed as the "fifth largest plastic" and is widely used in industry and construction due to its excellent properties. The two main raw materials for producing polyurethane are polyols and isocyanates. Isocyanates offer relatively few product types, mainly including MDI, TDI, HDI, and PAPI. Polyols, on the other hand, are a diverse group of monomers with varying qualities and diversified downstream applications, offering room for further research.

[0003] Currently, polyols and isocyanates are mainly derived from petroleum resources. With the depletion of petroleum resources and the intensification of environmental problems, the preparation of polyols or isocyanates from green and renewable biomass resources, and subsequently the synthesis of bio-based polyurethanes, has become one of the important directions for the development of my country's strategic emerging materials industry and biomass industry. Compared with petroleum-based polyurethane raw materials, bio-based polyurethane raw materials are less toxic, more abundant in sources, cheaper, and have more diverse structures, which is conducive to expanding the scale of industrial production and reducing production costs, while effectively improving the overall performance of polyurethane materials.

[0004] Research on bio-based polyurethanes mainly focuses on three aspects: bio-based polyols, bio-based isocyanates, and the preparation of bio-based chain extenders. Among these, the use of bio-based chain extenders to prepare polyurethanes has limited effect on increasing the bio-based content and is not a primary research focus. Bio-based isocyanates can be classified into aliphatic isocyanates, aromatic isocyanates, and symmetrical and asymmetrical isocyanates. Currently, dimer acid-modified aliphatic isocyanate products have been developed, but the application areas of polyurethanes prepared from these isocyanates are limited.

[0005] Polyurethane materials based on bio-based polyols have been extensively studied and show great application potential. The raw materials for bio-based polyols are widely available, mainly including lignocellulose, vegetable oils, sugars, and natural phenols. Vegetable oils are an important source of bio-based polyols. Compared to petroleum-based polyols, vegetable oil polyols have advantages such as abundant raw material resources, low energy consumption, low greenhouse gas emissions, and good physicochemical stability, making them an excellent alternative to petroleum-based polyols. They have good applications in polyurethane foams, adhesives, coatings, potting compounds, and structural adhesives. Currently, in the coatings field, the development of plant oil-derived bio-based polyols is relatively slow, especially in anti-corrosion coatings. Currently, polyurethane coatings developed using bio-based polyols struggle to achieve a balance in hardness, toughness, and corrosion resistance.

[0006] In the structure of vegetable oils, long-chain groups replace the repeating units of traditional petrochemical polyol polyethers or polyesters, and the basic triglyceride core in the structure has a star-shaped spatial conformation, endowing downstream polyurethanes with more functional properties and application space. However, vegetable oil polyols often have performance defects, mainly for two reasons:

[0007] First, the epoxidation-ring-opening reaction process of vegetable oils is uncontrollable. During the functional group transformation process, multiple epoxy groups and ester groups often participate in multiple side reaction processes. Therefore, the designed molecular structure is difficult to construct through traditional chemical methods, which greatly limits the quality of polyols. They often need to be mixed with traditional petrochemical polyols to achieve certain application effects.

[0008] Secondly, compared to petrochemical polyether polyols, vegetable oil polyols have secondary hydroxyl groups, resulting in greater steric hindrance and poorer reactivity and miscibility with isocyanates. The reaction mechanism between vegetable oil polyols and isocyanates differs from that of traditional petrochemical-based polyether polyols and isocyanates, with different rate-controlling steps. This makes the controllable polymerization technology used in traditional petrochemical-based polyurethane anticorrosive coatings unsuitable for vegetable oil-based polyurethanes. The multiple functional groups in the structure of vegetable oil polyols make it difficult to simultaneously achieve optimal reaction selectivity and conversion rate, resulting in poor process control and poor molecular uniformity, high viscosity, and significant differences between macroscopic and microscopic properties of individual molecules in the obtained polyurethane materials.

[0009] Therefore, a two-pronged approach is needed: First, given the diverse components and unclear structure-activity relationships of vegetable oils, quality control of polyol products should be implemented through reaction process control and macroscopic indicator regulation. Key technical indicators such as hydroxyl value and viscosity should be controlled within a certain range to meet the requirements of downstream anti-corrosion applications. Second, catalysts suitable for the polymerization of vegetable oil polyols and petrochemical-based isocyanates should be developed. Formula design and optimization should be completed to prepare bio-based polyurethane anti-corrosion coatings with performance indicators meeting the requirements of petrochemical-based anti-corrosion coatings, exhibiting excellent performance in terms of adhesion, VOC, and biocarbon content. Summary of the Invention

[0010] To address the shortcomings of existing technologies, this invention provides a plant oil-based polyurethane anti-corrosion coating.

[0011] To optimize the performance of downstream plant-oil-based polyurethane anticorrosion coatings, this invention replaces existing petrochemical-based polyethers or polyester polyols with plant-oil polyols. Through research on the polymerization mechanism of plant-oil polyols and isocyanates, and considering the differences in molecular structure and physical properties between plant-oil polyols and petrochemical-based polyols, an ionic liquid tertiary amine catalyst was developed to address the issues of poor reactivity and solubility between plant-oil polyols and isocyanates. The interaction between the molecular structure and key technical parameters (hydroxyl value and viscosity, etc.) of plant-oil polyols and the performance of polyurethane anticorrosion coatings (adhesion, salt spray resistance) was systematically studied. The structure-property relationship between polyols and materials was understood, and plant-oil polyols suitable for anticorrosion coatings were developed, with their key technical parameters determined. Based on the specific anticorrosion requirements of steel structures and industrial pipelines, the formulation design and optimization of plant-oil-based polyurethane anticorrosion coatings were carried out, ultimately developing an economical and stable plant-oil-based polyurethane anticorrosion coating.

[0012] To achieve the above objectives, the present invention is implemented through the following technical solution: a plant oil-based polyurethane anti-corrosion coating, comprising a primer, an intermediate coat, and a topcoat, wherein the primer comprises component A and component B, the intermediate coat comprises component C and component B, and the topcoat comprises component D and component B.

[0013] By weight:

[0014] Component A comprises: 20-30 parts of vegetable oil polyol, 0.1-0.5 parts of ionic liquid tertiary amine catalyst, 5-15 parts of anti-rust pigment, 5-20 parts of coloring powder, 10-25 parts of inert filler, 0.5-5 parts of aminosilane resin, 1-5 parts of anti-settling agent, and 10-20 parts of mixed solvent.

[0015] Component B comprises: 100 parts of isocyanate;

[0016] The C component comprises: 15-25 parts of vegetable oil polyol, 0.1-0.5 parts of ionic liquid tertiary amine catalyst, 3-15 parts of anti-rust pigment, 5-20 parts of coloring powder, 10-25 parts of inert filler, 0.5-5 parts of aminosilane resin, 1-5 parts of anti-settling agent, and 10-20 parts of mixed solvent.

[0017] The D component comprises: 40-70 parts of vegetable oil polyol, 0.1-0.5 parts of ionic liquid tertiary amine catalyst, 5-20 parts of coloring powder, 1-5 parts of additives, 5-20 parts of inert filler, 0.5-5 parts of aminosilane resin, 1-5 parts of anti-settling agent, and 10-20 parts of mixed solvent.

[0018] Preferably, the anti-rust pigment is one of strontium yellow phosphate, high-purity zinc phosphate, nano zinc oxide, and aluminum tripolyphosphate; the coloring powder is one of titanium dioxide, iron oxide red, phthalocyanine blue, and carbon black; the inert filler is one of talc and barium sulfate; the anti-settling agent is one of bentonite and fumed silica; and the additive is at least one of defoamer, dispersant, leveling agent, and antioxidant.

[0019] Preferably, the mass ratio of component A to component B is 5-15, and the mixing time is 5-15 min; the mass ratio of component C to component B is 5-15, and the mixing time is 5-15 min; the mass ratio of component D to component B is 5-15, and the mixing time is 5-15 min.

[0020] Preferably, the vegetable oil polyol is at least one selected from soybean oil polyol, sunflower seed oil polyol, cottonseed oil polyol, peanut oil polyol, coconut oil polyol, palm oil polyol, sesame oil polyol, and corn oil polyol.

[0021] Preferably, the vegetable oil polyol is soybean oil polyol or cottonseed oil polyol; the soybean oil polyol and cottonseed oil polyol are prepared by reacting epoxidized soybean oil and epoxidized cottonseed oil as raw materials, respectively, with fluoroboric acid, methanesulfonic acid, phosphoric acid or phosphotungstic acid as catalysts, and cyclohexanediol, cyclohexanediethanol, cyclohexanediethanol or mannitol as ring-opening agents. The amount of catalyst used is 0.5-2‰ of the mass of epoxidized soybean oil or epoxidized cottonseed oil, the molar ratio of the ring-opening agent to epoxidized soybean oil or epoxidized cottonseed oil is 2-6, the reaction temperature is 60-100℃, and the reaction time is 5-10h.

[0022] Preferably, the hydroxyl value of the plant oil polyol is 250-400 mg KOH / g, the viscosity is 500-800 mPa·s, and the epoxy value is 0-1.

[0023] Preferably, the ionic liquid tertiary amine catalyst is an imidazole / pyridine quaternary ammonium salt ionic liquid catalyst, and the amount of the ionic liquid tertiary amine catalyst added is 1-5‰ of the mass of the vegetable oil polyol.

[0024] Preferably, the isocyanate is at least one of diphenylmethane diisocyanate polymer, hexamethylene diisocyanate trimer, isoflurone diisocyanate, and polymethylene polyphenyl isocyanate.

[0025] Preferably, the preparation methods of components A, C, and D all include the following steps: weigh the raw materials of the formula amount and put them into a grinding cylinder, stir and disperse at high speed for 15-30 minutes, then enter the grinding process, control the outlet temperature of the sand mill to be below 50℃, grind more than three times or for no less than 4 hours until the fineness is less than 20μm, then enter the color matching process, adjust the color of the coating to meet the requirements of the standard color card, control the color difference value ΔE to be no more than 2%, add an appropriate amount of solvent, adjust the viscosity of the product to be less than 160s in the fourth cup of the Forecast, and finally filter to obtain the final product.

[0026] Preferably, the preparation method of component B includes the following steps: weighing the prescribed amount of isocyanate, mixing it, and then vacuum dehydrating it to obtain the final product.

[0027] In practical applications, the plant oil-based polyurethane anticorrosive coating of this invention is used in combination with a primer, intermediate coat, and topcoat for general corrosion protection of steel structures and metal pipelines, with an applicable temperature range of -20℃ to 120℃. The primer contains ≥70% non-volatile matter, ≤250g / L VOC content, ≥8MPa adhesion, and ≥50% biochar content. The intermediate coat contains ≥70% non-volatile matter, ≤250g / L VOC content, ≥8MPa adhesion, and ≥50% biochar content. The topcoat contains ≥60% non-volatile matter, ≤300g / L VOC content, ≥8MPa adhesion, and ≥30% biochar content.

[0028] This invention discloses a plant oil-based polyurethane anticorrosive coating, which has the following beneficial effects:

[0029] 1. This invention selects vegetable oil polyols to replace traditional petrochemical-based polyethers or polyester polyols. Compared with petrochemical-based polyols, vegetable oil polyols have advantages such as abundant raw material resources, low energy consumption, low greenhouse gas emissions, and excellent physicochemical stability. The molecular structure of vegetable oil polyols is rich in triglycerides, epoxy groups, hydroxyl groups, ester groups, cyclic hydrocarbons, and ether bonds, resulting in bio-based polyurethane materials with rich and highly controllable properties. Based on research into the structure-property relationship between key technical parameters of vegetable oil polyols and the properties of polyurethane materials, the hydroxyl value and viscosity range of vegetable oil polyols in vegetable oil-based polyurethane anticorrosive coatings have been optimized and limited, thereby improving the various technical properties of vegetable oil-based polyurethane anticorrosive coatings.

[0030] 2. Based on the research on the polymerization reaction mechanism of vegetable oil polyols and isocyanates, this invention uses a novel ionic liquid tertiary amine catalyst to catalyze the polymerization process of vegetable oil polyols and isocyanates, thereby improving the reaction activity and system miscibility, and thus meeting the requirements of anti-corrosion coatings for curing time, adhesion and corrosion resistance.

[0031] 3. In view of the different requirements of primer, intermediate coat and topcoat for anti-corrosion of steel structures and industrial pipelines, the present invention optimizes the formulation design of primer, intermediate coat and topcoat. Using the formulation and preparation method of the present invention, the prepared vegetable oil-based polyurethane anti-corrosion primer, intermediate coat and topcoat have performance indicators that meet those of petrochemical-based similar products. They are far superior to petrochemical-based similar products in terms of adhesion, salt water resistance and VOC content, and the biocarbon content is above 30%.

[0032] 4. The plant oil-based polyurethane anti-corrosion primer, intermediate coat and topcoat prepared by this invention can replace epoxy zinc-rich primer, epoxy iron oxide red intermediate coat and polyurethane / acrylic topcoat. When used together, their comprehensive performance is superior to similar petrochemical-based coatings. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] The relevant testing methods for the prepared vegetable oil-based polyurethane anticorrosive coating of this invention are as follows:

[0035] (1) The content of non-volatile substances in the coating was determined according to GB / T 1725-2007;

[0036] (2) The adhesion of the coating was tested according to GB / T 5210-2006 (pull-off method);

[0037] (3) The surface drying and hard drying times of the coatings were determined according to GB / T 1728-2020;

[0038] (4) The impact resistance of the coating was determined according to GB / T 1732-2020;

[0039] (5) The acid resistance, alkali resistance and salt water resistance of the topcoat shall be determined in accordance with GB / T 9274-1988;

[0040] (6) The coating’s resistance to neutral salt spray was determined according to GB / T 1771-2007;

[0041] (7) The resistance of the topcoat to artificial weathering was determined according to GB / T 1865-2009;

[0042] (8) Determine the biochar content of the coating according to ASTM D6866.

[0043] Example 1: A plant oil-based polyurethane anti-corrosion coating, comprising a primer, an intermediate coat, and a topcoat, wherein the primer comprises component A and component B, the intermediate coat comprises component C and component B, and the topcoat comprises component D and component B;

[0044] By weight:

[0045] Component A comprises: 25 parts of vegetable oil polyol, 0.2 parts of ionic liquid tertiary amine catalyst, 15 parts of anti-rust pigment, 15 parts of coloring powder, 20 parts of inert filler, 4 parts of aminosilane resin, 4 parts of anti-settling agent, and 16.8 parts of mixed solvent.

[0046] Component B comprises: 100 parts of diphenylmethane diisocyanate polymer;

[0047] The C component comprises: 20 parts of vegetable oil polyol, 0.3 parts of pyridine quaternary ammonium salt ionic liquid catalyst, 12 parts of anti-rust pigment, 18 parts of coloring powder, 23 parts of inert filler, 4 parts of aminosilane resin, 3 parts of anti-settling agent, and 19.7 parts of mixed solvent.

[0048] The D component comprises: 55 parts of vegetable oil polyol, 0.4 parts of pyridine quaternary ammonium salt ionic liquid catalyst, 15 parts of coloring powder, 3 parts of additives, 10 parts of inert filler, 2 parts of aminosilane resin, 2 parts of anti-settling agent, and 12.6 parts of mixed solvent.

[0049] The rust-preventive pigment is strontium yellow phosphate; the coloring powder is titanium dioxide; the inert filler is talc; the anti-settling agent is bentonite; and the additives are defoamer and dispersant.

[0050] The plant oil polyol is cottonseed oil polyol with a hydroxyl value of 300 mg KOH / g, a viscosity of 544 mPa·s, and an epoxy value of 0.5. The cottonseed oil polyol is prepared by reacting epoxidized cottonseed oil as raw material, using fluoroboric acid as a catalyst, and cyclohexanediol as a ring-opening agent. The amount of catalyst used is 1‰ of the mass of epoxidized cottonseed oil added. The molar ratio of the ring-opening agent to epoxidized cottonseed oil is 4. The reaction temperature is 90℃, and the reaction time is 6 h.

[0051] The preparation methods for components A, C, and D all include the following steps: weigh the raw materials according to the formula and put them into a grinding cylinder, stir and disperse at high speed for 20 minutes, then enter the grinding process, control the outlet temperature of the sand mill to be below 50℃, grind until the fineness is less than 20μm, then enter the color matching process, adjust the color of the coating to meet the requirements of the standard color card, control the color difference value ΔE to not exceed 2%, add an appropriate amount of solvent, adjust the viscosity of the product to less than 160s in the 4th cup, and finally filter to obtain the final product.

[0052] The preparation method of component B includes the following steps: weigh the prescribed amount of isocyanate, mix them, and then dehydrate them under vacuum.

[0053] Component A and Component B are mixed and stirred for 10 minutes at a mass ratio of 10 to obtain a plant oil-based polyurethane anti-corrosion primer. The plant oil-based polyurethane anti-corrosion primer is sprayed onto the steel plate substrate. One coat is applied, and the dry film thickness is 25 μm. After being left for 48 hours, non-volatile matter content, VOC, adhesion, acid resistance, alkali resistance, salt water resistance, neutral salt spray resistance, artificial weathering resistance, and biocarbon content are tested in a laboratory environment.

[0054] Components C and B are mixed and stirred for 15 minutes at a mass ratio of 10 to obtain a plant oil-based polyurethane anti-corrosion intermediate paint. The plant oil-based polyurethane anti-corrosion intermediate paint is sprayed onto the steel plate substrate. One coat is applied, and the dry film thickness is 50 μm. After being left for 48 hours, non-volatile matter content, VOC, adhesion, acid resistance, alkali resistance, salt water resistance, neutral salt spray resistance, artificial weathering resistance, and biocarbon content are tested in a laboratory environment.

[0055] The components D and B were mixed and stirred for 10 minutes at a mass ratio of 5 to obtain a plant oil-based polyurethane anti-corrosion topcoat. The plant oil-based polyurethane anti-corrosion topcoat was sprayed onto the steel plate substrate. One coat was applied, and the dry film thickness was 50 μm. After being left for 48 hours, the non-volatile matter content, VOC, adhesion, acid resistance, alkali resistance, salt water resistance, neutral salt spray resistance, artificial weathering resistance, and biocarbon content were tested in a laboratory environment.

[0056] The performance indicators of the plant oil-based polyurethane anti-corrosion primer, intermediate coat and topcoat described in Example 1 are shown in Table 1.

[0057] Table 1. Main performance indicators of vegetable oil-based polyurethane anticorrosion primer, intermediate coat and topcoat in Example 1

[0058]

[0059]

[0060] As can be seen from the data in Table 1, the plant oil-based polyurethane anticorrosive primer, intermediate coat and topcoat of the present invention, compared with petrochemical-based similar products, have a 25.8% higher non-volatile content, a VOC content of more than 50.8%, an adhesion of more than 2.5 times, a bio-carbon content of more than 30%, and other indicators meet the requirements of petrochemical-based similar products.

[0061] Example 2: A plant oil-based polyurethane anti-corrosion coating, comprising a primer, an intermediate coat, and a topcoat, wherein the primer comprises component A and component B, the intermediate coat comprises component C and component B, and the topcoat comprises component D and component B;

[0062] By weight:

[0063] Component A comprises: 20 parts of vegetable oil polyol, 0.5 parts of ionic liquid tertiary amine catalyst, 5 parts of anti-rust pigment, 20 parts of coloring powder, 10 parts of inert filler, 5 parts of aminosilane resin, 1 part of anti-settling agent, and 20 parts of mixed solvent.

[0064] Component B comprises: 100 parts of hexamethylene diisocyanate trimer;

[0065] The C component comprises: 15 parts of vegetable oil polyol, 0.5 parts of ionic liquid tertiary amine catalyst, 3 parts of anti-rust pigment, 20 parts of coloring powder, 10 parts of inert filler, 5 parts of aminosilane resin, 1 part of anti-settling agent, and 20 parts of mixed solvent.

[0066] The D component comprises: 40 parts of vegetable oil polyol, 0.5 parts of ionic liquid tertiary amine catalyst, 5 parts of coloring powder, 5 parts of additives, 5 parts of inert filler, 5 parts of aminosilane resin, 1 part of anti-settling agent, and 20 parts of mixed solvent.

[0067] The rust-preventive pigment is high-purity zinc phosphate; the coloring powder is iron oxide red; the inert filler is barium sulfate; the anti-settling agent is fumed silica; and the additives are leveling agent and antioxidant.

[0068] The plant oil polyol is soybean oil polyol, with a hydroxyl value of 250 mg KOH / g, a viscosity of 500 mPa·s, and an epoxy value of 0.2. The soybean oil polyol is produced using epoxidized soybean oil as raw material, methanesulfonic acid as catalyst, and cyclohexanediol as ring-opening agent. The amount of catalyst used is 0.5‰ of the mass of epoxidized soybean oil added. The molar ratio of the ring-opening agent to epoxidized soybean oil is 2. The reaction temperature is 60℃, and the reaction time is 5 h.

[0069] The preparation methods for components A, C, and D all include the following steps: weigh the raw materials according to the formula and put them into a grinding cylinder, stir and disperse at high speed for 15 minutes, then enter the grinding process, control the outlet temperature of the sand mill to be below 50℃, grind until the fineness is less than 20μm, then enter the color matching process, adjust the color of the coating to meet the requirements of the standard color card, control the color difference value ΔE to not exceed 2%, add an appropriate amount of solvent, adjust the viscosity of the product to less than 160s in the 4th cup, and finally filter to obtain the final product.

[0070] The preparation method of component B includes the following steps: weigh the prescribed amount of isocyanate, mix them, and then dehydrate them under vacuum.

[0071] Components A and B are mixed and stirred for 10 minutes at a mass ratio of 10 to obtain a plant oil-based polyurethane anti-corrosion primer. The plant oil-based polyurethane anti-corrosion primer is sprayed onto the steel plate substrate. One coat is applied, and the dry film thickness is 25 μm. After being left for 48 hours, non-volatile matter content, VOC, adhesion, acid resistance, alkali resistance, salt water resistance, neutral salt spray resistance, artificial weathering resistance, and biocarbon content are tested in a laboratory environment.

[0072] Components C and B are mixed and stirred for 15 minutes at a mass ratio of 10 to obtain a plant oil-based polyurethane anti-corrosion intermediate paint. The plant oil-based polyurethane anti-corrosion intermediate paint is sprayed onto the steel plate substrate. One coat is applied, and the dry film thickness is 50 μm. After being left for 48 hours, non-volatile matter content, VOC, adhesion, acid resistance, alkali resistance, salt water resistance, neutral salt spray resistance, artificial weathering resistance, and biocarbon content are tested in a laboratory environment.

[0073] The components D and B were mixed and stirred for 10 minutes at a mass ratio of 5 to obtain a plant oil-based polyurethane anti-corrosion topcoat. The plant oil-based polyurethane anti-corrosion topcoat was sprayed onto the steel plate substrate. One coat was applied, and the dry film thickness was 50 μm. After being left for 48 hours, the non-volatile matter content, VOC, adhesion, acid resistance, alkali resistance, salt water resistance, neutral salt spray resistance, artificial weathering resistance, and biocarbon content were tested in a laboratory environment.

[0074] The performance indicators of the vegetable oil-based polyurethane anti-corrosion primer, intermediate coat and topcoat described in Example 2 are shown in Table 2.

[0075] Table 2. Main performance indicators of vegetable oil-based polyurethane anti-corrosion primer, intermediate coat and topcoat in Example 2

[0076]

[0077]

[0078] Example 3: A plant oil-based polyurethane anti-corrosion coating, comprising a primer, an intermediate coat, and a topcoat, wherein the primer comprises component A and component B, the intermediate coat comprises component C and component B, and the topcoat comprises component D and component B;

[0079] By weight:

[0080] Component A comprises: 30 parts of vegetable oil polyol, 0.1 parts of ionic liquid tertiary amine catalyst, 15 parts of anti-rust pigment, 5 parts of coloring powder, 25 parts of inert filler, 0.5 parts of aminosilane resin, 5 parts of anti-settling agent, and 10 parts of mixed solvent.

[0081] Component B comprises: 100 parts of isoflurone diisocyanate;

[0082] The C component comprises: 25 parts of vegetable oil polyol, 0.1 parts of ionic liquid tertiary amine catalyst, 15 parts of anti-rust pigment, 5 parts of coloring powder, 25 parts of inert filler, 0.5 parts of aminosilane resin, 5 parts of anti-settling agent, and 10 parts of mixed solvent.

[0083] The D component comprises: 70 parts of vegetable oil polyol, 0.1 parts of ionic liquid tertiary amine catalyst, 20 parts of coloring powder, 1 part of additive, 20 parts of inert filler, 0.5 parts of aminosilane resin, 5 parts of anti-settling agent, and 10 parts of mixed solvent.

[0084] The rust-preventive pigment is nano zinc oxide; the coloring powder is carbon black; the inert filler is talc; the anti-settling agent is bentonite; and the additives are defoamer and antioxidant.

[0085] The plant oil polyol is cottonseed oil polyol, with a hydroxyl value of 400 mg KOH / g, a viscosity of 800 mPa·s, and an epoxy value of 0.9. The cottonseed oil polyol is produced using epoxidized cottonseed oil as raw material, phosphoric acid as catalyst, and mannitol as ring-opening agent. The amount of catalyst added is 2‰ of the mass of epoxidized cottonseed oil. The molar ratio of the ring-opening agent to epoxidized cottonseed oil is 6. The reaction temperature is 100℃, and the reaction time is 10 h.

[0086] The preparation methods for components A, C, and D all include the following steps: weigh the raw materials according to the formula and put them into a grinding cylinder, stir and disperse at high speed for 30 minutes, then enter the grinding process, control the outlet temperature of the sand mill to be below 50℃, grind until the fineness is less than 20μm, then enter the color matching process, adjust the color of the coating to meet the requirements of the standard color card, control the color difference value ΔE to not exceed 2%, add an appropriate amount of solvent, adjust the viscosity of the product to less than 160s in the 4th cup, and finally filter to obtain the final product.

[0087] The preparation method of component B includes the following steps: weigh the prescribed amount of isocyanate, mix them, and then dehydrate them under vacuum.

[0088] Components A and B are mixed and stirred for 10 minutes at a mass ratio of 10 to obtain a plant oil-based polyurethane anti-corrosion primer. The plant oil-based polyurethane anti-corrosion primer is sprayed onto the steel plate substrate. One coat is applied, and the dry film thickness is 25 μm. After being left for 48 hours, non-volatile matter content, VOC, adhesion, acid resistance, alkali resistance, salt water resistance, neutral salt spray resistance, artificial weathering resistance, and biocarbon content are tested in a laboratory environment.

[0089] Components C and B are mixed and stirred for 15 minutes at a mass ratio of 10 to obtain a plant oil-based polyurethane anti-corrosion intermediate paint. The plant oil-based polyurethane anti-corrosion intermediate paint is sprayed onto the steel plate substrate. One coat is applied, and the dry film thickness is 50 μm. After being left for 48 hours, non-volatile matter content, VOC, adhesion, acid resistance, alkali resistance, salt water resistance, neutral salt spray resistance, artificial weathering resistance, and biocarbon content are tested in a laboratory environment.

[0090] The components D and B were mixed and stirred for 10 minutes at a mass ratio of 5 to obtain a plant oil-based polyurethane anti-corrosion topcoat. The plant oil-based polyurethane anti-corrosion topcoat was sprayed onto the steel plate substrate. One coat was applied, and the dry film thickness was 50 μm. After being left for 48 hours, the non-volatile matter content, VOC, adhesion, acid resistance, alkali resistance, salt water resistance, neutral salt spray resistance, artificial weathering resistance, and biocarbon content were tested in a laboratory environment.

[0091] The performance indicators of the plant oil-based polyurethane anti-corrosion primer, intermediate coat and topcoat described in Example 3 are shown in Table 3.

[0092] Table 3. Main performance indicators of vegetable oil-based polyurethane anti-corrosion primer, intermediate coat and topcoat in Example 3

[0093] Test Project primer Intermediate paint Topcoat Petrochemical-based similar products Non-volatile matter content (after mixing A and B), % ≥ 86.1 85.6 75.0 60 VOC (g / L) (after mixing A and B) 221 228 249 500 / 500 / 550 Adhesion (pull-off method) / MPa 17 14 13 6 <![CDATA[Acid resistance (50g / L H2SO4)]]> / / No abnormalities in 168 hours No abnormalities in 168 hours Alkali resistance (20g / L NaOH) / / No abnormalities in 168 hours No abnormalities in 168 hours Salt water resistance (3% NaCl solution) qualified qualified qualified qualified Resistance to neutral salt spray / / 1000h 1000h Resistance to artificial weathering / / 1000h 1000h Biomass content % 57.8 54.6 35.7 0

[0094] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A plant oil-based polyurethane anticorrosive coating, characterized in that, It includes a primer, an intermediate coat, and a topcoat. The primer contains components A and B, the intermediate coat contains components C and B, and the topcoat contains components D and B. By weight: Component A comprises: 20-30 parts of vegetable oil polyol, 0.1-0.5 parts of ionic liquid tertiary amine catalyst, 5-15 parts of anti-rust pigment, 5-20 parts of coloring powder, 10-25 parts of inert filler, 0.5-5 parts of aminosilane resin, 1-5 parts of anti-settling agent, and 10-20 parts of mixed solvent. Component B comprises: 100 parts of isocyanate; The C component comprises: 15-25 parts of vegetable oil polyol, 0.1-0.5 parts of ionic liquid tertiary amine catalyst, 3-15 parts of anti-rust pigment, 5-20 parts of coloring powder, 10-25 parts of inert filler, 0.5-5 parts of aminosilane resin, 1-5 parts of anti-settling agent, and 10-20 parts of mixed solvent. The D component comprises: 40-70 parts of vegetable oil polyol, 0.1-0.5 parts of ionic liquid tertiary amine catalyst, 5-20 parts of coloring powder, 1-5 parts of additives, 5-20 parts of inert filler, 0.5-5 parts of aminosilane resin, 1-5 parts of anti-settling agent, and 10-20 parts of mixed solvent. The plant oil polyol is soybean oil polyol or cottonseed oil polyol; the soybean oil polyol and cottonseed oil polyol are prepared by reacting epoxidized soybean oil and epoxidized cottonseed oil, respectively, with fluoroboric acid, methanesulfonic acid, phosphoric acid or phosphotungstic acid as catalysts, and cyclohexanediol, cyclohexanediol, cyclohexanediethanol or mannitol as ring-opening agents. The amount of catalyst used is 0.5-2‰ of the mass of epoxidized soybean oil or epoxidized cottonseed oil, the molar ratio of the ring-opening agent to epoxidized soybean oil or epoxidized cottonseed oil is 2-6, the reaction temperature is 60-100℃, and the reaction time is 5-10h; the hydroxyl value of the plant oil polyol is 250-400mgKOH / g, the viscosity is 500-800mPa•s, and the epoxy value is 0-1. The ionic liquid tertiary amine catalyst is an imidazole / pyridine quaternary ammonium salt ionic liquid catalyst, and the amount of the ionic liquid tertiary amine catalyst added is 1-5‰ of the mass of the vegetable oil polyol. The mass ratio of component A to component B is 5-15, and the mixing time is 5-15 min; the mass ratio of component C to component B is 5-15, and the mixing time is 5-15 min; the mass ratio of component D to component B is 5-15, and the mixing time is 5-15 min.

2. The vegetable oil-based polyurethane anticorrosive coating according to claim 1, characterized in that, The anti-rust pigment is one of strontium yellow phosphate, high-purity zinc phosphate, nano zinc oxide, and aluminum tripolyphosphate; the coloring powder is one of titanium dioxide, iron oxide red, phthalocyanine blue, and carbon black; the inert filler is one of talc and barium sulfate; the anti-settling agent is one of bentonite and fumed silica; and the additive is at least one of defoamer, dispersant, leveling agent, and antioxidant.

3. The vegetable oil-based polyurethane anticorrosive coating according to claim 1 or 2, characterized in that, The isocyanate is at least one of diphenylmethane diisocyanate polymer, hexamethylene diisocyanate trimer, isoflurone diisocyanate, and polymethylene polyphenyl isocyanate.

4. The vegetable oil-based polyurethane anticorrosive coating according to claim 1 or 2, characterized in that, The preparation methods for components A, C, and D all include the following steps: weigh the raw materials according to the formula and put them into a grinding cylinder, stir and disperse at high speed for 15-30 minutes, then proceed to the grinding process, control the outlet temperature of the sand mill to be below 50℃, grind three times or more or for no less than 4 hours until the fineness is less than 20μm, then proceed to the color matching process, adjust the color of the coating to meet the requirements of the standard color card, control the color difference value ΔE to be no more than 2%, add an appropriate amount of solvent, adjust the viscosity of the product to be less than 160s in the fourth cup of the Forecast, and finally filter to obtain the final product.

5. The vegetable oil-based polyurethane anticorrosive coating according to claim 1 or 2, characterized in that, The preparation method of component B includes the following steps: weigh the prescribed amount of isocyanate, mix them, and then dehydrate them under vacuum.

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