A superhydrophobic single-component aliphatic polyurea coating, its preparation method and application

Abstract

This invention relates to the field of coating technology, specifically to a superhydrophobic one-component aliphatic polyurea coating, its preparation method, and its application. The superhydrophobic one-component aliphatic polyurea coating, by weight, comprises the following raw materials: 30-40 parts aliphatic isocyanate, 30-40 parts polyether polyol, 10-15 parts polyester polyol, 8-12 parts fluorosilicone oligomer, 2-4 parts chain extender, 10-15 parts blocking agent, 0.1-0.5 parts catalyst, and 10-20 parts diluent. The one-component polyurea coating prepared by this invention not only possesses excellent mechanical properties but also achieves a superhydrophobic effect after film formation, while exhibiting high durability.

Description

Technical Field

[0001] This invention relates to the field of coating technology, specifically to a superhydrophobic single-component aliphatic polyurea coating, its preparation method, and its application. Background Technology

[0002] Polyurea coatings, emerging as high-performance protective materials in the 1980s, have achieved rapid application in waterproofing, corrosion protection, and abrasion resistance due to the high stability of their urea bond (-NH-CO-NH-) structure, becoming a significant upgrade direction for traditional coatings. Early commercialized polyurea was primarily a two-component aromatic system, relying on the rapid reaction between isocyanate-terminated prepolymers and amino-terminated polyethers, offering advantages such as second-level curing, high strength, and high elasticity, and was widely used in concrete protection and steel structure corrosion protection. However, this system has significant drawbacks: the molecule contains benzene rings, making it prone to yellowing and chalking after long-term outdoor exposure; it also has poor weather resistance, requiring additional weather-resistant topcoats, increasing construction steps and costs; furthermore, the two-component system requires precise on-site mixing and relies on specialized spraying equipment, resulting in a complex construction process. Defects in the coating can easily occur due to mixing deviations or uneven mixing. Additionally, the rapid curing leads to a short operating window, placing extremely high demands on construction personnel and equipment, limiting its application in small-scale projects, repair work, and complex working conditions. To address the construction pain points of two-component systems, single-component polyurea coatings have gradually become a research hotspot.

[0003] Patent CN117106366B discloses a one-component polyurea coating, its preparation method, and its application. The polyurea coating is prepared from the following raw materials in parts by weight: 40-55 parts diisocyanate, 15-30 parts diluent, 100-120 parts glycol composition, 0.2-0.4 parts leveling agent, 0.3-0.5 parts defoamer, 60-80 parts silane sealant, 30-35 parts polyamine, and 1-2 parts catalyst. The one-component polyurea prepared by this invention exhibits excellent processing performance, simple and convenient construction, good adhesion to the substrate, no CO2 gas generation during curing, no pinhole bubbles, good waterproof, temperature resistance, and corrosion resistance properties, good storage stability, high strength and toughness, low water absorption, excellent seepage prevention effect, and wide application. Patent CN119264795A discloses a one-component polyurea coating, comprising the following raw materials in parts by weight: 150-200 parts of polyether polyol, 60-80 parts of isocyanate, 20-35 parts of polyamine, 60-80 parts of filler, 0.5-1 part of defoamer, 1-3 parts of catalyst, and 10-20 parts of thixotropic agent; the thixotropic agent is modified bentonite, which is obtained by modifying bentonite with a modifier, namely hydroxyl polydimethylsiloxane and isocyanate-based propyltriethoxysilane. This technical solution solves the problem of poor mechanical properties and adhesion of one-component polyurea coatings in related technologies.

[0004] While the above patents improve the temperature resistance, mechanical properties, and adhesion of polyurea coatings from different aspects, in fields such as industrial protection, building waterproofing, and marine engineering, the substrates are constantly subjected to complex conditions such as rainwater erosion, sewage corrosion, ice and snow adhesion, and pollutant deposition. This not only shortens the service life of the substrates but also increases maintenance costs. Superhydrophobic coatings can effectively resist the damage to the substrates caused by harsh external environments and have become one of the core development directions of functional protective coatings. Therefore, the research and development of superhydrophobic polyurea coatings is particularly important. Summary of the Invention

[0005] In view of the problems existing in the prior art, the purpose of this invention is to obtain a single-component polyurea coating that not only has good mechanical properties, but also achieves superhydrophobic effect after film formation, and has high durability.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The first aspect of this invention provides a superhydrophobic single-component aliphatic polyurea coating, comprising, by weight, the following raw materials: 30-40 parts aliphatic isocyanate, 30-40 parts polyether polyol, 10-15 parts polyester polyol, 8-12 parts fluorosilicone oligomer, 2-4 parts chain extender, 10-15 parts blocking agent, 0.1-0.5 parts catalyst, and 10-20 parts diluent.

[0007] In this invention, aliphatic isocyanates and mixed polyols first generate NCO-terminated prepolymers under the action of a catalyst. Subsequently, active fluorosilicone oligomers and small-molecule chain extenders are introduced to participate in the chain growth reaction, firmly anchoring low surface energy segments in the polyurea molecular network in the form of covalent bonds. Finally, the residual NCO is end-capped using a blocking agent to obtain a storage-stable single-component system. After application, the coating is desealed and cured by moisture in the air or by adding water, fundamentally solving the problem of poor compatibility between low surface energy components and polar polyurea resins, and the problem of easy phase separation leading to mechanical property degradation. In addition, the fluorosilicone block copolymer structure spontaneously and directionally accumulates on the coating surface during film formation, and the high cross-linking density skeleton constructed by the polyester / polyether polyol complex system not only achieves a superhydrophobic and self-cleaning effect on the coating surface, but also gives the coating significant application advantages in building waterproofing, offshore wind power, and bridge corrosion protection.

[0008] In some embodiments, the polyisocyanate is at least one of isophorone diisocyanate, hexamethylene diisocyanate, and dicyclohexylmethane diisocyanate.

[0009] In some embodiments, the polyether polyol is polytetrahydrofuran ether diol, and the polyester polyol is polycaprolactone diol or polycarbonate diol.

[0010] In some embodiments, the method for preparing the fluorosilicone oligomer includes the following steps: Under nitrogen protection, diamino-terminated polysiloxanes were added to toluene, and hexafluorobutyl methacrylate was added while stirring. Then, a polymerization inhibitor and triethylamine were added, and the mixture was reacted at 60-70°C for 6-8 hours. After post-treatment, fluorosilicone oligomers were obtained.

[0011] This invention utilizes the Michael addition reaction pathway to chemically block copolymerize diamino-terminated polysiloxanes with hexafluorobutyl methacrylate, preparing a terminal-amino reactive fluorosilicone oligomer with both a flexible siloxane backbone and extremely low surface energy fluorocarbon side chains. This fundamentally solves the technical problems of uncontrollable migration rates of low surface energy components in polar polyurea matrices and easy loss after surface enrichment, leading to poor hydrophobic durability. The prepared fluorosilicone oligomer retains some amino groups at both ends of its molecular chain, which can be covalently integrated into the resin network in subsequent polyurea coating synthesis. This chemically anchors the low surface energy segments in the three-dimensional structure of the coating, ensuring stable superhydrophobic performance even after long-term exposure to rain or mechanical wear. Furthermore, by replacing physical blending with chemical bonding, the resin bulk phase separation defects caused by significant differences in surface energy are completely eliminated, endowing the coating with superhydrophobic self-cleaning properties while fully preserving the excellent mechanical properties of aliphatic polyurea.

[0012] In some embodiments, the molar ratio of amino groups to hexafluorobutyl methacrylate in the diamino-terminated polysiloxane is 1:(0.3-0.6).

[0013] In some embodiments, the chain extender is butanediol.

[0014] In some embodiments, the blocking agent is a ketimine.

[0015] In some embodiments, the diluent is N-methyl-2-pyrrolidone.

[0016] In some embodiments, the catalyst is dibutyltin dilaurate.

[0017] A second aspect of this invention provides a method for preparing a superhydrophobic single-component aliphatic polyurea coating, comprising the following steps: Polyester polyol and polyether polyol are added to a reactor, vacuum is applied, and then the mixture is heated to 110-120℃ and stirred at a constant temperature for 1-2 hours. N2 is then continuously introduced into the reactor while maintaining atmospheric pressure. The temperature is lowered to 90-95℃ and stirred at a constant temperature for 20-25 minutes. Aliphatic isocyanate is then added and reacted for 1.5-2.5 hours. Fluorosilicone oligomer and chain extender are then added and the reaction continues for 60-70 minutes. Finally, the temperature is lowered to 80-85℃, a catalyst is added, and the reaction continues for 30-50 minutes. A diluent is then added and stirred for 15-20 minutes. Finally, a blocking agent is added and stirred for 30-40 minutes. The mixture is then filtered to obtain a superhydrophobic single-component aliphatic polyurea coating.

[0018] The third aspect of this invention provides an application of a superhydrophobic single-component aliphatic polyurea coating, wherein, by weight, 15-30 parts of solvent, 0.1-0.5 parts of defoamer, 0.1-0.5 parts of dispersant, and 0.2-0.4 parts of leveling agent are added during use.

[0019] In some embodiments, the solvent is a mixture of ethanol, n-hexane, and acetone.

[0020] Preferably, the volume ratio of ethanol, n-hexane, and acetone is 1:(0.8-1.2):(0.3-0.7).

[0021] More preferably, the volume ratio of ethanol, n-hexane, and acetone is 1:1:0.5.

[0022] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention uses aliphatic isocyanate, polyether polyol, polyester polyol, fluorosilicone oligomer and other additives to prepare a one-component polyurea coating, which not only has good mechanical properties, but also achieves superhydrophobic effect after film formation, and has high durability.

[0023] (2) In this invention, an NCO-terminated prepolymer is generated by reacting aliphatic isocyanate with mixed polyols under the action of a catalyst. Subsequently, an active fluorosilicone oligomer and a chain extender are introduced to promote chain growth, and then the prepolymer is sealed with a blocking agent to obtain a storage-stable single-component system. After construction, the system is desealed and cured by moisture. The fluorosilicone block structure spontaneously accumulates on the surface during film formation, and works synergistically with the polyester / polyether composite skeleton to build a high crosslinking density coating. This solves the problem of poor compatibility between hydrophobic components and resins and easy phase separation leading to mechanical decay, and endows the coating with superhydrophobic self-cleaning function.

[0024] (3) The present invention uses Michael addition to copolymerize diamino-terminated polysiloxane with hexafluorobutyl methacrylate to obtain a terminal amino reactive fluorosilicone oligomer with both flexible siloxane main chain and fluorocarbon side chain. The oligomer is covalently anchored to the polyurea network, which solves the problem of poor hydrophobic durability caused by the migration and loss of low surface energy components. At the same time, chemical bonding replaces physical blending to eliminate phase separation defects, giving the coating a self-cleaning function while fully retaining the excellent mechanical properties of aliphatic polyurea. Detailed Implementation

[0025] The present invention will be described below with reference to specific embodiments. It should be noted that the following embodiments are examples of the present invention and are used only to illustrate the invention, not to limit it. Other combinations and various modifications within the scope of the present invention can be made without departing from its spirit or scope.

[0026] In the following examples and comparative examples, the compounds and related reagents used were all commercially available. Among them, the Mn of polytetrahydrofuran ether diol was 2000; the Mn of polycaprolactone diol was 2000; the diamino-terminated polysiloxane was diamino-terminated polydimethylsiloxane with Mn=1000; the defoamer was BYK-088; the dispersant was BYK-9076; and the leveling agent was BYK-331.

[0027] Unless otherwise specified, the post-processing steps such as "washing", "drying", "filtration", "rotary evaporation", and "reduced pressure distillation" used below are routine operations for those skilled in the art, and can be selected according to actual operation.

[0028] Preparation Example 1 The preparation method of fluorosilicone oligomer-1 includes the following steps: Under nitrogen protection, diamino-terminated polydimethylsiloxane containing 10 mmol of amino groups was added to 100 ml of toluene. While stirring, 5 mmol of hexafluorobutyl methacrylate was added, followed by 0.005 mmol of hydroquinone and 0.05 mmol of triethylamine. The mixture was reacted at 65 °C for 7 h, and then rotary evaporated to obtain the crude product. The crude product was added to deionized water and stirred for 10 min. After standing and separating into layers, the water layer was removed and dried to obtain fluorosilicone oligomer-1.

[0029] Preparation Example 2 The preparation method of fluorosilicone oligomer-2 is the same as that in preparation example 1, except that the amount of hexafluorobutyl methacrylate added is 7 mmol.

[0030] Preparation Example 3 The preparation method of fluorosilicone oligomer-3 is the same as that in preparation example 1, except that the equimolar amount of hexafluorobutyl methacrylate is replaced with tridecafluorooctyl methacrylate.

[0031] Example 1 A superhydrophobic one-component aliphatic polyurea coating, comprising, by weight, the following raw materials: 35 parts dicyclohexylmethane diisocyanate, 35 parts polytetrahydrofuran ether diol, 13 parts polycaprolactone diol, 10 parts fluorosilicone oligomer-1, 3 parts butanediol, 13 parts ketimine, 0.3 parts dibutyltin dilaurate, and 15 parts N-methyl-2-pyrrolidone.

[0032] The preparation method of the superhydrophobic single-component aliphatic polyurea coating in this embodiment includes the following steps: Polycaprolactone diol and polytetrahydrofuran ether diol were added to a reactor, and a vacuum was drawn and maintained at -0.095 MPa. The reactor was then heated to 115°C and stirred at a constant temperature for 1.5 h. N2 was continuously introduced into the reactor while maintaining atmospheric pressure. The temperature was lowered to 93°C and stirred at a constant temperature for 23 min. Dicyclohexylmethane diisocyanate was then added and reacted for 2 h. Fluorosilicone oligomer-1 and butanediol were then added and the reaction continued for 65 min. Finally, the temperature was lowered to 83°C and dibutyltin dilaurate was added and reacted for 40 min. N-methyl-2-pyrrolidone was added and stirred for 18 min. Finally, ketoimine was added at room temperature and stirred for 35 min. The mixture was then filtered to obtain a superhydrophobic one-component aliphatic polyurea coating.

[0033] Example 2 A superhydrophobic one-component aliphatic polyurea coating, comprising, by weight, the following raw materials: 30 parts dicyclohexylmethane diisocyanate, 30 parts polytetrahydrofuran ether diol, 10 parts polycaprolactone diol, 8 parts fluorosilicone oligomer-1, 2 parts butanediol, 10 parts ketimine, 0.1 parts dibutyltin dilaurate, and 10 parts N-methyl-2-pyrrolidone.

[0034] The preparation method of the superhydrophobic single-component aliphatic polyurea coating in this embodiment includes the following steps: Polycaprolactone diol and polytetrahydrofuran ether diol were added to a reactor, and a vacuum was drawn to maintain a vacuum of -0.095 MPa. The reactor was then heated to 110°C and stirred at a constant temperature for 2 hours. N2 was continuously introduced into the reactor while maintaining atmospheric pressure. The temperature was lowered to 90°C and stirred at a constant temperature for 25 minutes. Dicyclohexylmethane diisocyanate was then added and reacted for 1.5 hours. Fluorosilicone oligomer-1 and butanediol were then added and the reaction continued for 60 minutes. Finally, the temperature was lowered to 80°C and dibutyltin dilaurate was added and reacted for 30 minutes. N-methyl-2-pyrrolidone was then added and stirred for 15 minutes. Finally, ketoimine was added at room temperature and stirred for 30 minutes. The mixture was then filtered to obtain a superhydrophobic one-component aliphatic polyurea coating.

[0035] Example 3 A superhydrophobic one-component aliphatic polyurea coating, comprising, by weight, the following raw materials: 40 parts dicyclohexylmethane diisocyanate, 40 parts polytetrahydrofuran ether diol, 15 parts polycaprolactone diol, 12 parts fluorosilicone oligomer-1, 4 parts butanediol, 15 parts ketimine, 0.5 parts dibutyltin dilaurate, and 20 parts N-methyl-2-pyrrolidone.

[0036] The preparation method of the superhydrophobic single-component aliphatic polyurea coating in this embodiment includes the following steps: Polycaprolactone diol and polytetrahydrofuran ether diol were added to a reactor, and a vacuum was drawn to maintain a vacuum of -0.095 MPa. The reactor was then heated to 120°C and stirred at a constant temperature for 1 hour. N2 was continuously introduced into the reactor while maintaining atmospheric pressure. The temperature was lowered to 95°C and stirred at a constant temperature for 20 minutes. Dicyclohexylmethane diisocyanate was then added and reacted for 2.5 hours. Fluorosilicone oligomer-1 and butanediol were then added and the reaction continued for 70 minutes. Finally, the temperature was lowered to 85°C and dibutyltin dilaurate was added and reacted for 50 minutes. N-methyl-2-pyrrolidone was then added and stirred for 20 minutes. Finally, ketoimine was added at room temperature and stirred for 40 minutes. The mixture was then filtered to obtain a superhydrophobic one-component aliphatic polyurea coating.

[0037] Example 4 A superhydrophobic single-component aliphatic polyurea coating and its preparation method are disclosed. The specific implementation method is the same as that in Example 1, except that fluorosilicone oligomer-1 is replaced with fluorosilicone oligomer-2 in equal amounts.

[0038] Example 5 A superhydrophobic single-component aliphatic polyurea coating and its preparation method are disclosed. The specific implementation method is the same as that in Example 1, except that fluorosilicone oligomer-1 is replaced with fluorosilicone oligomer-3 in equal amounts.

[0039] Comparative Example 1 A superhydrophobic single-component aliphatic polyurea coating and its preparation method are disclosed. The specific implementation method is the same as that in Example 1, except that the fluorosilicone oligomer-1 is replaced with an equal amount of diamino-terminated polydimethylsiloxane.

[0040] Comparative Example 2 A superhydrophobic single-component aliphatic polyurea coating and its preparation method are disclosed. The specific implementation method is the same as that in Example 1, except that the fluorosilicone oligomer-1 is replaced with hexafluorobutyl methacrylate in an equal amount.

[0041] Performance testing 22 parts by weight of solvent, 0.3 parts by weight of defoamer, 0.3 parts by weight of dispersant, and 0.3 parts by weight of leveling agent were added to the superhydrophobic single-component aliphatic polyurea coatings obtained in each embodiment and comparative example, and the mixture was stirred for 15 minutes. The solvent was a mixture of anhydrous ethanol, n-hexane, and acetone in a volume ratio of 1:1:0.5. The following tests were then performed: 1. Tensile strength: Tested according to GB / T16777-2008 "Test Methods for Waterproof Coatings for Buildings" using a universal testing machine, with a test speed of 50 mm / min and a test temperature of (20±2)℃; 2. Hydrophobicity: The superhydrophobic single-component aliphatic polyurea coatings obtained in each example and comparative example were coated on an aluminum plate with a coating thickness of 50 μm. The plate was placed at 50°C and 50% relative humidity for 24 hours, and the water contact angle was tested.

[0042] The test results are shown in Table 1: Table 1

[0043] As shown in Table 1, the single-component polyurea coatings of Examples 1-3 and 5 exhibit good mechanical and hydrophobic properties. A comparison of the data from Example 4 and Example 1 reveals that the altered ratio of amino groups to hexafluorobutyl methacrylate in the diamino-terminated polysiloxane may have resulted in excessive fluorocarbon side chains creating steric hindrance in the molecular chain, hindering the orderly arrangement of low surface energy segments on the surface. Consequently, the effective enrichment of fluorine on the surface did not meet expectations, leading to a decrease in both the mechanical and hydrophobic properties of the coating. A comparison between Comparative Example 1 and Example 1 shows that the direct diamino-terminated polydimethylsiloxane has poor compatibility with the polyurea matrix. Although chemical bonding through the terminal amino groups is possible, the silicon-oxygen... Alkyl segments are prone to microphase separation during curing, which disrupts the regular microphase structure of the polyurea hard-soft segments, leading to a decrease in the mechanical properties and hydrophobicity of the coating. As can be seen from the comparison between Comparative Example 2 and Example 1, when hexafluorobutyl methacrylate is used directly, it is a monofunctional small molecule. When added directly to the system, it can only act as a capping agent or graft monomer and cannot participate in the chain growth reaction. Moreover, a large number of free small molecules exist in the system as plasticizers, which seriously weakens the polymer network structure and leads to a decrease in the mechanical properties of the coating. At the same time, the small molecule fluorine monomers are difficult to migrate effectively to the surface during curing, resulting in limited hydrophobic effect and a decrease in the hydrophobicity of the coating.

[0044] 3. Based on the test results in Table 1, the polyurea coatings from Examples 1-3 and Example 5 were applied to prepare coatings according to the method in the hydrophobicity test. The coatings were then immersed in 10wt% H2SO4 solution, 10wt% NaOH solution, 10wt% NaCl solution, and anhydrous methanol at room temperature for 168 hours, and then immersed in machine oil at 120℃ for 168 hours. The changes on the coating surface were observed, and the results are shown in Table 2. Table 2

[0045] As can be seen from the data in Table 2, the polyurea coatings prepared in Examples 1-3 of the present invention have good durability. As can be seen from the comparison of the data in Example 5 and Example 1, during the film formation process, the surface tension of the excessively long perfluorocarbon chains is too low, and the enrichment rate on the coating surface is too fast, resulting in uneven micro-nano structure inside the coating film and reduced coating durability.

[0046] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it. They should not be used to limit the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A superhydrophobic one-component aliphatic polyurea coating, characterized in that, By weight, it includes the following raw materials: 30-40 parts aliphatic isocyanate, 30-40 parts polyether polyol, 10-15 parts polyester polyol, 8-12 parts fluorosilicone oligomer, 2-4 parts chain extender, 10-15 parts blocking agent, 0.1-0.5 parts catalyst, and 10-20 parts diluent.

2. The superhydrophobic single-component aliphatic polyurea coating according to claim 1, characterized in that, The polyisocyanate is at least one of isophorone diisocyanate, hexamethylene diisocyanate, and dicyclohexylmethane diisocyanate.

3. The superhydrophobic single-component aliphatic polyurea coating according to claim 1, characterized in that, The polyether polyol is polytetrahydrofuran ether diol, and the polyester polyol is polycaprolactone diol or polycarbonate diol.

4. The superhydrophobic single-component aliphatic polyurea coating according to claim 1, characterized in that, The method for preparing the fluorosilicone oligomer includes the following steps: Under nitrogen protection, diamino-terminated polysiloxanes were added to toluene, and hexafluorobutyl methacrylate was added while stirring. Then, a polymerization inhibitor and triethylamine were added, and the mixture was reacted at 60-70°C for 6-8 hours. After post-treatment, fluorosilicone oligomers were obtained.

5. The superhydrophobic single-component aliphatic polyurea coating according to claim 4, characterized in that, The molar ratio of amino groups to hexafluorobutyl methacrylate in the diamino-terminated polysiloxane is 1:(0.3-0.6).

6. The superhydrophobic single-component aliphatic polyurea coating according to claim 1, characterized in that, The chain extender is butanediol.

7. The superhydrophobic single-component aliphatic polyurea coating according to claim 1, characterized in that, The sealing agent is ketimine.

8. The superhydrophobic single-component aliphatic polyurea coating according to claim 1, characterized in that, The diluent is N-methyl-2-pyrrolidone.

9. A method for preparing a superhydrophobic single-component aliphatic polyurea coating according to any one of claims 1-8, characterized in that, Includes the following steps: Polyester polyol and polyether polyol are added to a reactor, vacuum is applied, and then the mixture is heated to 110-120℃ and stirred at a constant temperature for 1-2 hours. N2 is then continuously introduced into the reactor while maintaining atmospheric pressure. The temperature is lowered to 90-95℃ and stirred at a constant temperature for 20-25 minutes. Aliphatic isocyanate is then added and reacted for 1.5-2.5 hours. Fluorosilicone oligomer and chain extender are then added and the reaction continues for 60-70 minutes. Finally, the temperature is lowered to 80-85℃ and a catalyst is added, and the reaction continues for 30-50 minutes. A diluent is then added and stirred for 15-20 minutes. Finally, a blocking agent is added at room temperature and the mixture is stirred for 30-40 minutes. The mixture is then filtered to obtain a superhydrophobic single-component aliphatic polyurea coating.

10. The application of a superhydrophobic single-component aliphatic polyurea coating according to any one of claims 1-8 or a polyurea coating obtained by the preparation method according to claim 9, characterized in that, By weight, add 15-30 parts solvent, 0.1-0.5 parts defoamer, 0.1-0.5 parts dispersant, and 0.2-0.4 parts leveling agent when using.

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