CN110684456B - Microcrystalline cellulose-fluorine modified polyurethane coating and preparation method and application thereof - Google Patents
Microcrystalline cellulose-fluorine modified polyurethane coating and preparation method and application thereof Download PDFInfo
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- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
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- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
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- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
- C08G18/40—High-molecular-weight compounds
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- C09D5/08—Anti-corrosive paints
Abstract
The invention relates to the technical field of materials, and discloses a microcrystalline cellulose-fluorine modified polyurethane coating which comprises a component A and a component B, wherein the component A adopts hydroxyl-containing fluororesin and polytetrahydrofuran ether glycol as soft segments of polyurethane, so that the hydrophobicity and the corrosion resistance of the polyurethane are improved; in the component B, microcrystalline cellulose is swelled and then reacts with isocyanate to form a cross-linked structure which is used as a hard segment of polyurethane, so that the tensile strength of the polyurethane is improved. The hard segments are regularly arranged and tightly stacked due to the cross-linking structure of the hard segments, the soft segments are difficult to enter the hard segments, the microphase separation degree of the hard and soft polyurethane segments is improved, and the coating prepared from the obtained polyurethane coating has good mechanical property, cavitation erosion resistance and corrosion resistance. The coating can be widely applied to equipment such as propellers, water turbine blades, pumps, pipelines, valves and the like, and the service time of the coating is prolonged.
Description
Technical Field
The invention relates to the technical field of materials, in particular to a microcrystalline cellulose-fluorine modified polyurethane coating and a preparation method and application thereof.
Background
Cavitation erosion is also called cavitation erosion, and cavitation erosion refers to that under the condition of high-speed multiphase flow, local pressure change in a liquid medium causes cavitation bubbles to form and collapse, the high-speed liquid contains the cavitation bubbles, so that abrasion and corrosion are serious, and the material is continuously impacted by high-pressure and high-speed micro jet to damage the surface of metal. Therefore, the protective film on the metal surface is damaged to a certain extent, the metal particles are torn to a certain extent, the surface of the metal is broken, the corrosion occurs, and finally, dense and deep holes are formed on the surface of the metal, and the surface is rough. Metal cavitation often occurs in equipment such as pump impellers and hydraulic turbines, which causes the material performance to be sharply reduced, and the service life and the use quality of the equipment are seriously influenced.
The harm of cavitation erosion can be effectively reduced by using the cavitation erosion resistant layer, and the current cavitation erosion resistant layer is mainly an organic coating and a thermal spraying coating. Although thermal spray coatings have good cavitation erosion resistance, thermal spray coatings are not corrosion resistant and are relatively complex to construct, which limits their range of use. The organic coating mainly takes polyurethane as a main material, although some polyurethane coatings have excellent cavitation erosion resistance, the performance of the polyurethane coating still has certain limitation, the water resistance is insufficient, the most important factor influencing the application of the aqueous polyurethane coating in practice, the bonding force with a substrate after the aqueous polyurethane coating is used for a period of time is greatly reduced, and the whole sheet falls off after long-time cavitation erosion. The main reason for the reduction of the bonding force between polyurethane and the body is that polyurethane absorbs certain moisture, and the moisture can plasticize the polyurethane, thereby reducing the strength of the polyurethane and the bonding force between the polyurethane and the base material.
CN 106893481A discloses a polyvinyl alcohol fiber-fluorinated polyurethane cavitation erosion resistant coating and a preparation method thereof, firstly, a film forming material of the coating is fluorinated polyurethane, and the coating has the advantages of high adhesive force, toughness, weather resistance, chemical medium resistance, temperature resistance, low surface energy, low friction and the like. Secondly, the high-strength and high-modulus polyvinyl alcohol fiber is added into the coating as a filler, so that the coating has the properties of high tensile strength and modulus, acid and alkali resistance, ageing resistance, corrosion resistance, weather resistance and the like, and the performance of the coating can be further improved by effectively matching the filler with a coating film forming material. And finally, preparing the isocyanate grafted high-strength high-modulus polyvinyl alcohol fiber as a filler through a grafting reaction of hydroxyl on the surface of the high-strength high-modulus polyvinyl alcohol fiber and isocyanate. The coating is coated at normal temperature to prepare an anti-cavitation coating, has the characteristics of easy production, simple and convenient coating, light weight, erosion resistance, corrosion resistance and the like, and is mainly used for protecting propellers, pumps, valves, pipelines and the like in a cavitation environment.
The fluorine-containing material has lower surface energy, and fluorine atoms are introduced into the polyurethane, so that the hydrophobicity and corrosion resistance of the polyurethane can be greatly improved, and the friction coefficient is reduced, thereby improving the stability of the coating in a severe cavitation environment for a long time. However, the high-strength polyvinyl alcohol fiber has a large molecular weight, and when the high-strength polyvinyl alcohol fiber is directly added into a polyurethane reaction system, the reaction between hydroxyl groups in the high-strength polyvinyl alcohol and isocyanate in the polyurethane system is weak, and the chemical crosslinking between the polyvinyl alcohol fiber and polyurethane is less, which is not favorable for further enhancing the strength of the polyurethane system. And the patent only tested the bonding force of the coating which was not soaked in water to the substrate, and the bonding force of the coating to the substrate after soaking in water was unknown. Therefore, the need for further improvement of the adhesion between the polyurethane coating and the substrate still remains.
Disclosure of Invention
The invention aims to improve the cavitation erosion resistance of the polyurethane coating, and the polyurethane coating with strong hydrophobicity, weak water absorption, high strength and good cavitation erosion resistance can be obtained by mixing and reacting the microcrystalline cellulose modified isocyanate serving as the component B with the component A containing the hydroxyl fluorine resin.
In order to achieve the purpose, the invention adopts the technical scheme that:
the microcrystalline cellulose-fluorine modified polyurethane coating comprises the following components in parts by mass:
(1) the component A comprises:
(2) and B component:
the weight average molecular weight of the hydroxyl-containing fluororesin is 300-3500, the hydroxyl-containing fluororesin comprises at least 2 hydroxyl functional groups, the fluorine content is more than 3 wt%, and the fluorine groups can be arranged on a main chain and/or a side chain. When the main chain contains fluorine groups, the hydroxyl-containing fluororesin has stronger hydrophobicity, and the contact angle between the polyurethane synthesized by the hydroxyl-containing fluororesin and water can reach more than 105 degrees; the performance is more excellent when the main chain and the side chain both contain fluorine-containing groups, and the contact angle of the polyurethane synthesized by the polyurethane with water can reach over 115 degrees.
The hydroxyl-containing fluororesin can be prepared by a commercially available product or the following preparation method, and comprises the following steps:
(1) dissolving fluororubber in a solvent, adding a phase transfer catalyst, an oxidant and alkali, stirring to perform an oxidative degradation reaction to obtain carboxyl-containing fluororesin;
(2) dissolving the carboxyl-containing fluororesin obtained in the step (1) in a solvent, and carrying out reduction reaction to obtain the hydroxyl-containing fluororesin.
Preferably, after the reaction of step (1) and step (2) is completed, the reaction mixture is acidified with hydrochloric acid to promote the formation of carboxyl groups and hydroxyl groups on the fluororesin segments.
The hydroxyl-containing fluororesin prepared by the method has better hydrophobicity, good elasticity and low-temperature performance, can not be hardened at 0 ℃, has the fluorine content of more than 50 percent and has good weather resistance.
The phase transfer catalyst is benzyltriethylammonium chloride; the oxidant is hydrogen peroxide; the alkali is sodium hydroxide or potassium hydroxide; the solvent is acetone, N-Dimethylformamide (DMF) or Tetrahydrofuran (THF).
The reducing agent used in the reduction reaction is lithium aluminum hydride, a methanol solution of sodium borohydride or a compound of sodium borohydride and bromine. The molar ratio of the sodium borohydride to the bromine in the compound of the sodium borohydride and the bromine is 1: 0.5-2.
Preferably, the temperature of the oxidative degradation reaction in step (1) is below 25 ℃; the reaction time is similar in the field, and is preferably 4-8 h.
The proportion of reactants adopts the proportion of similar reactions in the field, preferably, when the mass of the fluororubber is 25g, the dosage of the oxidant is 0.15-0.55 mol, the dosage of the alkali is 0.08-0.35 mol, and the dosage of the phase transfer catalyst is 1.2 multiplied by 10-3～9×10- 3mol。
Preferably, the temperature of the reduction reaction in step (2) is from ice bath to room temperature; the reaction time is similar in the field, and preferably 2-8 h.
The addition amount of the reducing agent is the addition amount of the same kind of reaction in the field, and preferably 1.5X 10/g of carboxyl-containing fluororesin is added-2～7×10-2A reducing agent in mol; further preferably, 2X 10 is added per gram of the carboxyl group-containing fluororesin-2～5×10- 2The effect is better when the reducing agent is mol.
The weight average molecular weight of the polytetrahydrofuran ether glycol is 500-3000. The polyurethane synthesized in the molecular weight range has moderate hardness, proper strength and excellent comprehensive performance; polytetrahydrofuran ether glycol is a common soft polyurethane chain with low water absorption and excellent comprehensive properties, and is moderate in price and suitable for large-scale use.
The diluent is N, N-dimethylformamide and/or dimethyl sulfoxide (DMSO). Is used for reducing the viscosity of the whole coating and is convenient for film forming.
In order to obtain the polyurethane coating with better comprehensive performance, some auxiliary agents commonly used in the field can be added into the system, and the auxiliary agent A in the invention is preferably at least two of a defoaming agent, a leveling agent, an adhesion promoter and a thickening agent.
The isocyanate is a commercially common isocyanate, and is preferably any one of toluene diisocyanate, toluene diisocyanate trimer, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, hexamethylene diisocyanate biuret, hexamethylene diisocyanate trimer and isophorone diisocyanate.
The grain size of the microcrystalline cellulose is 10-100 mu m, and the material synthesized in the grain size range has the best comprehensive performance.
Although microcrystalline cellulose contains a large amount of hydroxyl groups, the crystallinity of the microcrystalline cellulose is too high, the microcrystalline cellulose is directly added for use, and the hydroxyl groups in the microcrystalline cellulose are difficult to react with isocyanate. A small amount of lithium chloride is added into the component B to swell the microcrystalline cellulose, so that hydroxyl of the cellulose can be reacted with isocyanate more easily to form a cross-linked structure; after one or more isocyanate groups in the isocyanate react with hydroxyl groups of the microcrystalline cellulose, other isocyanate groups can react with hydroxyl groups of the fluorine resin containing hydroxyl groups and the polytetrahydrofuran ether glycol in the component A to form polyurethane chains, so that the microcrystalline cellulose and the whole polyurethane chains are combined in a large number of chemical layers, and the strength of the polyurethane is greatly enhanced. Compared with the method of directly adding microcrystalline cellulose into polyurethane, the strength of the polyurethane can be improved by more than 30%.
The preparation method of the cavitation erosion resistant coating of the microcrystalline cellulose-fluorine modified polyurethane comprises the following steps:
(1) the preparation method of the component A comprises the following steps: under the protection of dry inert gas, uniformly stirring hydroxyl-containing fluororesin, polytetrahydrofuran ether glycol, an auxiliary agent A and a diluent in an anhydrous closed environment to obtain a component A, and drying, sealing and storing;
(2) the preparation method of the component B comprises the following steps: under the protection of dry inert gas, stirring microcrystalline cellulose, lithium chloride and a diluent in an anhydrous closed environment at room temperature to 100 ℃ for reaction for 4-10 h, then adding isocyanate, continuously reacting at room temperature to 120 ℃ for 0.5-3 h to obtain the component B, and drying, sealing and storing;
and (2) uniformly mixing the component A obtained in the step (1) and the component B obtained in the step (1) in a dry environment to obtain the polyurethane coating. The proportion of the component A and the component B can be specifically adjusted according to the hardness requirement, if a high-hardness coating needs to be obtained, the component B is properly added, and if a high-elasticity coating needs to be obtained, the component A is properly added.
In order to prevent poor binding force between the polyurethane coating and a substrate in the later period caused by water absorption, the whole preparation process is carried out in an anhydrous drying environment, and all raw materials are dehydrated and dried before use, so that the low water content of the raw materials is ensured.
The introduction of fluorine element in the component A can reduce the surface energy of the polyurethane coating, thereby reducing the water absorption of the polyurethane coating, and the obtained polyurethane coating has weak water absorption, and when the coating is used for a long time, the bonding force with a substrate is not seriously reduced due to excessive water absorption, so that a large amount of the coating falls off; the polytetrahydrofuran ether glycol in the component A can increase the rebound resilience and the water resistance of the whole polyurethane coating, and the whole component A is used as a soft segment of the polyurethane coating.
After the microcrystalline cellulose in the component B is swelled by lithium chloride, hydroxyl in the microcrystalline cellulose reacts with partial isocyanate groups in isocyanate, so that one end of the isocyanate is chemically connected with the microcrystalline cellulose, the other end of the isocyanate reacts with hydroxyl-containing fluororesin and polytetrahydrofuran ether glycol in the component A to obtain a polyurethane chain segment, wherein the component B is used as a hard segment of polyurethane, and the cross-linking structure in the component B ensures that the hard segments are regularly arranged and tightly stacked, so that the component A serving as a soft segment is difficult to enter the hard segment, the microphase separation degree of the hard and soft segments of the polyurethane is improved, the mechanical strength of the polyurethane coating is improved, and the cavitation erosion resistance of the polyurethane coating is further improved.
The invention also provides an application of the microcrystalline cellulose-fluorine modified polyurethane coating in preparing an anti-cavitation coating, which comprises the following steps: and (3) coating the polyurethane coating on the surface of a base material in a spraying, brushing or dipping mode, and curing to obtain the cavitation erosion resistant coating. The obtained cavitation erosion resistant coating has strong binding force with a substrate and excellent cavitation erosion resistance.
In the preparation of the cavitation erosion resistant coating, the surface of the substrate can be pretreated, and the pretreatment comprises the following steps:
(1) cleaning the surface of the base material by using ethanol or acetone;
(2) after drying, the substrate is grit blasted.
The pollutants and rust on the surface of the substrate can be removed through pretreatment, so that the polyurethane coating and the substrate have better binding force; and the spraying or brushing times are determined according to the required coating thickness, and the sprayed or brushed coating can be cured at normal temperature or cured by heating.
Compared with the prior art, the invention has the following beneficial effects:
(1) the microcrystalline cellulose in the polyurethane coating reacts with isocyanate to form a cross-linked structure, so that the tensile strength of polyurethane is greatly improved, and the formed polyurethane coating has good hydrophobicity, strong corrosion resistance and good mechanical property.
(2) The paint has simple production process and light weight, can be coated by brushing, spraying or dipping and the like, has good cavitation erosion resistance and corrosion resistance, can be widely applied to equipment such as propellers, water turbine blades, pumps, pipelines, valves and the like, and prolongs the service time of the equipment.
Drawings
Figure 1 is a plot of cumulative cavitation loss versus volume after 10 hours of ultrasonic cavitation of an anti-cavitation coating and untreated 316 stainless steel in application example 1.
Fig. 2 is a graph of cumulative cavitation loss in volume versus cavitation loss after 10 hours of ultrasonic cavitation of the cavitation resistant coating and untreated 316 stainless steel in application example 2.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. Those skilled in the art should understand that they can make modifications and equivalents without departing from the spirit and scope of the present invention, and all such modifications and equivalents are intended to be included within the scope of the present invention.
The raw materials used in the examples were all commercially available except for the hydroxyl-containing fluororesin.
Example 1
Preparation of hydroxyl-containing fluororesin having weight average molecular weight of about 1500:
(1) 25g of binary fluororubber (manufacturer: Zhonghao Chenguang, product name FKM 2604) were dissolved in acetone solution, and 0.09mol of potassium hydroxide solution, 0.2mol of hydrogen peroxide solution and 6X 10 mol of hydrogen peroxide solution were added-3Stirring and reacting the mol of benzyltriethylammonium chloride for 6-8 h at room temperature; then 0.22mol of hydrochloric acid is added for acidification for 30 min; separating to obtain a layer liquid, washing, and drying by rotary evaporation to obtain carboxyl-containing fluororesin with the weight-average molecular weight of about 1500;
(2) taking 1g of the carboxyl-containing fluororesin synthesized in the previous step, dissolving the carboxyl-containing fluororesin in tetrahydrofuran, and adding 3X 10 of the carboxyl-containing fluororesin under ice bath- 2Gradually heating mol lithium aluminum hydride to room temperature, stirring and reacting for 5h, adding 0.1mol hydrochloric acid for acidifying for 30min, separating to leave a layer liquid, washing, and spin-drying to obtain the hydroxyl-containing fluororesin with the weight-average molecular weight of about 1500, wherein the fluorine content of the hydroxyl-containing fluororesin is 60-85%.
Preparation of microcrystalline cellulose-fluorine modified polyurethane coating:
(1) the preparation method of the component A comprises the following steps: drying a fluororesin containing hydroxyl with the weight-average molecular weight of about 1500, polytetrahydrofuran ether glycol with the weight-average molecular weight of about 1000, a defoaming agent and an adhesion promoter in a vacuum oven at 80 ℃ for 24 hours respectively to remove water, sealing and storing, and dehydrating DMF (dimethyl formamide) by using a molecular sieve and then sealing and storing;
under the protection of dry high-purity argon, adding 35g of dry hydroxyl-containing fluororesin, 70g of polytetrahydrofuran ether glycol, 1g of defoaming agent, 0.8g of adhesion promoter and 150g of DMF (dimethyl formamide) into an anhydrous closed container with a stirring device, uniformly stirring to obtain a component A, and storing in a dry closed storage tank;
(2) the preparation method of the component B comprises the following steps: baking microcrystalline cellulose with the particle size of 50 mu m in a vacuum oven at 75 ℃ for 48 hours to remove water, and sealing and storing for later use;
under the protection of dry high-purity argon, adding 25g of microcrystalline cellulose, 0.6g of lithium chloride and 80g of DMF (dimethyl formamide) into an anhydrous closed container with a stirring device, stirring at 80 ℃ for reaction for 6 hours, adding 150g of toluene diisocyanate, heating to 90 ℃, continuing stirring for reaction for 2 hours to obtain a component B, and storing in a dry closed storage tank;
mixing the component A and the component B according to the mass ratio of 1:0.5, adding the mixture into a dry container, and uniformly stirring to obtain the microcrystalline cellulose-fluorine modified polyurethane coating.
Example 2
Preparation of hydroxyl-containing fluororesin having weight average molecular weight of about 1000:
(1) 25g of binary fluororubber (manufacturer: Zhonghao Chenguang, product name FKM 2604) were dissolved in acetone solution, and 0.18mol of potassium hydroxide solution, 0.5mol of hydrogen peroxide solution and 7X 10 mol of hydrogen peroxide solution were added-3Stirring and reacting the mol of benzyltriethylammonium chloride for 6-8 h at room temperature; adding 0.35mol hydrochloric acid for acidification for 30 min; separating to obtain a layer liquid, washing, and drying by rotary evaporation to obtain carboxyl-containing fluororesin with the weight-average molecular weight of about 1500;
(2) taking 1g of the carboxyl-containing fluororesin synthesized in the previous step, dissolving the carboxyl-containing fluororesin in tetrahydrofuran, and adding 5X 10 of the carboxyl-containing fluororesin under ice bath- 2And (2) gradually heating mol of a compound of sodium borohydride and bromine (wherein the molar ratio of the sodium borohydride to the bromine is 1:1) to room temperature, stirring and reacting for 5 hours, adding 0.15mol of hydrochloric acid to acidify for 30 minutes, separating to leave a layer liquid, washing, and spin-drying to obtain the hydroxyl-containing fluororesin with the weight-average molecular weight of about 1000, wherein the fluorine content of the hydroxyl-containing fluororesin is 65-80%.
Preparation of microcrystalline cellulose-fluorine modified polyurethane coating:
(1) the preparation method of the component A comprises the following steps: drying hydroxyl-containing fluororesin with the weight-average molecular weight of about 1000, polytetrahydrofuran ether glycol with the weight-average molecular weight of about 2000, a defoaming agent and an adhesion promoter in a vacuum oven at 80 ℃ for 24 hours respectively to remove water, sealing and storing, and dehydrating DMF (dimethyl formamide) by using a molecular sieve and then sealing and storing;
under the protection of dry high-purity argon, adding 50g of hydroxyl-containing fluororesin, 80g of polytetrahydrofuran ether glycol, 1.2g of defoaming agent, 1g of adhesion promoter and 180g of DMF (dimethyl formamide) into an anhydrous closed container with a stirring device, uniformly stirring to obtain a component A, and storing in a dry closed storage tank;
(2) the preparation method of the component B comprises the following steps: baking microcrystalline cellulose with the particle size of 20 mu m in a vacuum oven at the temperature of 80 ℃ for 48 hours to remove water, and sealing and storing for later use;
under the protection of dry high-purity argon, adding 15g of microcrystalline cellulose, 0.8g of lithium chloride and 100g of DMF (dimethyl formamide) into an anhydrous closed container with a stirring device, stirring at 80 ℃ for reaction for 8 hours, adding 130g of hexamethylene diisocyanate trimer, heating to 90 ℃, continuing stirring for reaction for 2 hours to obtain a component B, and storing in a dry closed storage tank;
mixing the component A and the component B according to the mass ratio of 1: 0.6, adding the mixture into a dry container, and uniformly stirring to obtain the microcrystalline cellulose-fluorine modified polyurethane coating.
Application example 1
Taking 316 stainless steel as a matrix, cleaning the surface of the matrix with acetone, and then performing sand blasting treatment to remove impurities and dirt on the surface of the matrix; the polyurethane coating prepared in example 1 was uniformly applied to the surface of the substrate subjected to impurity removal and sand blasting with a brush, and cured at room temperature for 48 hours to obtain an anti-cavitation coating.
And testing the cavitation performance of the cured coating according to an ASTM-G32-2010 ultrasonic cavitation method, wherein the frequency of an ultrasonic cavitation device is set to be 20KHz, the amplitude is +/-50 mu m, the distance between an ultrasonic cavitation head and the surface of a sample is 1mm, the cavitation head is immersed in water for 23 +/-2 mm, the test solution is deionized water, and the water temperature is kept at 25 +/-2 ℃.
The results obtained after 10 hours of ultrasonic cavitation erosion of untreated 316 stainless steel as a reference are shown in FIG. 1, and the cumulative cavitation erosion loss volume of the untreated 316 stainless steel was found to be 4mm3While the cumulative cavitation lost volume of 316 stainless steel with cavitation erosion resistant coating is only 3.4mm3It can be seen that the cavitation erosion resistance of the cavitation erosion resistant coating prepared using the microcrystalline cellulose-fluorine modified polyurethane coating obtained in example 1 was 1.2 times that of 316 stainless steel.
After being soaked in water for 720 hours, 316 stainless steel with the cavitation erosion resistant coating is tested for the binding force between the cavitation erosion resistant coating and the substrate according to ISO4624, and the result shows that the binding strength between the cavitation erosion resistant coating and the substrate after soaking still maintains 11 MPa.
Application example 2
Taking 316 stainless steel as a matrix, cleaning the surface of the matrix with acetone, and then performing sand blasting treatment to remove impurities and dirt on the surface of the matrix; the polyurethane coating prepared in example 2 was uniformly applied to the surface of the substrate subjected to impurity removal and sand blasting with a brush, and cured at room temperature for 48 hours to obtain an anti-cavitation coating.
And testing the cavitation performance of the cured coating according to an ASTM-G32-2010 ultrasonic cavitation method, wherein the frequency of an ultrasonic cavitation device is set to be 20KHz, the amplitude is +/-50 mu m, the distance between an ultrasonic cavitation head and the surface of a sample is 1mm, the cavitation head is immersed in water for 23 +/-2 mm, the test solution is deionized water, and the water temperature is kept at 25 +/-2 ℃.
The results obtained after 10 hours of ultrasonic cavitation erosion of untreated 316 stainless steel as a reference are shown in FIG. 2, and the cumulative cavitation erosion loss volume of the untreated 316 stainless steel was found to be 4mm3While the cumulative cavitation lost volume of 316 stainless steel with cavitation erosion resistant coating is only 3.2mm3The cavitation erosion resistance of the cavitation erosion resistant coating is 1.4 times that of 316 stainless steel.
After being soaked in water for 720 hours, 316 stainless steel with the cavitation erosion resistant coating is tested for the binding force between the cavitation erosion resistant coating and the substrate according to ISO4624, and the result shows that the binding strength between the cavitation erosion resistant coating and the substrate after soaking still maintains 10.5 MPa.
Claims (9)
1. The microcrystalline cellulose-fluorine modified polyurethane coating is characterized by comprising the following components in parts by mass:
(1) the component A comprises:
(2) and B component:
the hydroxyl-containing fluororesin is prepared by the following method, and comprises the following steps:
(1) dissolving fluororubber in a solvent, adding a phase transfer catalyst, an oxidant and alkali, stirring to perform an oxidative degradation reaction to obtain carboxyl-containing fluororesin;
(2) dissolving the carboxyl-containing fluororesin obtained in the step (1) in a solvent, and performing reduction reaction to obtain the hydroxyl-containing fluororesin;
the phase transfer catalyst is benzyltriethylammonium chloride; the oxidant is hydrogen peroxide; the alkali is sodium hydroxide or potassium hydroxide.
2. A microcrystalline cellulose-fluorine modified polyurethane coating material according to claim 1, wherein the weight average molecular weight of the hydroxyl-containing fluororesin is 300 to 3500, and comprises at least 2 hydroxyl functional groups, and the fluorine content is 3 wt% or more.
3. A microcrystalline cellulose-fluorine modified polyurethane coating according to claim 1, characterised in that the solvent is acetone, N-dimethylformamide or tetrahydrofuran.
4. A microcrystalline cellulose-fluorine modified polyurethane coating according to claim 1, characterised in that the reducing agent used in the reduction reaction is lithium aluminium hydride, sodium borohydride in methanol or a complex of sodium borohydride and bromine.
5. A microcrystalline cellulose-fluorine modified polyurethane coating according to claim 1, characterised in that the diluent is N, N-dimethylformamide and/or dimethylsulfoxide.
6. The microcrystalline cellulose-fluorine modified polyurethane coating according to claim 1, wherein the auxiliary agent is at least two of a defoaming agent, a leveling agent, an adhesion promoter and a thickening agent.
7. A microcrystalline cellulose-fluorine modified polyurethane coating material according to claim 1, wherein the microcrystalline cellulose particle size is 10 to 100 μm.
8. The method for preparing microcrystalline cellulose-fluorine modified polyurethane coating according to any one of claims 1 to 7, characterized by comprising the steps of:
(1) the preparation method of the component A comprises the following steps: under the protection of dry inert gas, uniformly stirring hydroxyl-containing fluororesin, polytetrahydrofuran ether glycol, an auxiliary agent and a diluent in an anhydrous closed environment to obtain a component A, and drying, sealing and storing;
(2) the preparation method of the component B comprises the following steps: under the protection of dry inert gas, stirring microcrystalline cellulose, lithium chloride and a diluent in an anhydrous closed environment for reacting for 4-10 h, adding isocyanate, continuously reacting for 0.5-3 h to obtain the component B, and drying, sealing and storing;
and (3) uniformly mixing the component A obtained in the step (1) and the component B obtained in the step (2) in a dry environment to obtain the polyurethane coating.
9. The application of the microcrystalline cellulose-fluorine modified polyurethane coating according to any one of claims 1-7 in preparing an anti-cavitation coating comprises the following steps: and (3) coating the polyurethane coating on the surface of a base material in a spraying, brushing or dipping mode, and curing to obtain the cavitation erosion resistant coating.
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| CN112321732B (en) * | 2020-10-26 | 2023-03-10 | 衢州学院 | Hydrophobic modified cellulose and preparation method thereof |
| US20220306876A1 (en) * | 2021-03-29 | 2022-09-29 | Micro Powders, Inc. | Biodegradable Cellulosic Powders |
| CN114644879B (en) * | 2022-03-10 | 2022-11-11 | 吉林大学 | Cavitation-corrosion-resistant, antifouling and anticorrosive multifunctional paint and coating |
| CN114672239B (en) * | 2022-04-01 | 2022-11-18 | 吉林大学 | Cavitation-corrosion-resistant and corrosion-resistant multifunctional paint and coating |
| CN114989385A (en) * | 2022-05-16 | 2022-09-02 | 广州市聚科聚氨酯有限公司 | Modified isocyanate and preparation method thereof |
| CN116218347B (en) * | 2022-06-24 | 2024-02-06 | 国家电投集团科学技术研究院有限公司 | Cavitation erosion resistant finish paint and preparation method and application thereof |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0525795A2 (en) * | 1991-08-02 | 1993-02-03 | AUSIMONT S.p.A. | Use of fluorinated polyurethanes for the treatment of films or sheets made of cellulose, graphite, mica, kaolin, leather and similar natural materials |
| CN102618162A (en) * | 2012-04-09 | 2012-08-01 | 中国科学院宁波材料技术与工程研究所 | Preparation method of fire retardant coating |
| CN106893481A (en) * | 2015-12-17 | 2017-06-27 | 中国科学院金属研究所 | A kind of anti-cavitation corrosion coating of vinal-fluoride polyurethane and preparation method thereof |
| CN107936808A (en) * | 2017-11-30 | 2018-04-20 | 安徽卓尔航空科技有限公司 | A kind of high water-fast fluorocarbon coatings of anti-cavitation corrosion |
| CN108587271A (en) * | 2018-05-17 | 2018-09-28 | 东莞市大兴化工有限公司 | A kind of aqueous UV polyurethane coatings and preparation method thereof |
| CN108610721A (en) * | 2018-05-17 | 2018-10-02 | 东莞市大兴化工有限公司 | Flame-retardant modified polyurethane curing agent and preparation method and double-component polyurethane coating |
-
2019
- 2019-10-30 CN CN201911044457.1A patent/CN110684456B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0525795A2 (en) * | 1991-08-02 | 1993-02-03 | AUSIMONT S.p.A. | Use of fluorinated polyurethanes for the treatment of films or sheets made of cellulose, graphite, mica, kaolin, leather and similar natural materials |
| CN102618162A (en) * | 2012-04-09 | 2012-08-01 | 中国科学院宁波材料技术与工程研究所 | Preparation method of fire retardant coating |
| CN106893481A (en) * | 2015-12-17 | 2017-06-27 | 中国科学院金属研究所 | A kind of anti-cavitation corrosion coating of vinal-fluoride polyurethane and preparation method thereof |
| CN107936808A (en) * | 2017-11-30 | 2018-04-20 | 安徽卓尔航空科技有限公司 | A kind of high water-fast fluorocarbon coatings of anti-cavitation corrosion |
| CN108587271A (en) * | 2018-05-17 | 2018-09-28 | 东莞市大兴化工有限公司 | A kind of aqueous UV polyurethane coatings and preparation method thereof |
| CN108610721A (en) * | 2018-05-17 | 2018-10-02 | 东莞市大兴化工有限公司 | Flame-retardant modified polyurethane curing agent and preparation method and double-component polyurethane coating |
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