CN111574893B - Method for improving corrosion resistance of polyvinyl alcohol water-based paint through temperature rise secondary curing - Google Patents

Method for improving corrosion resistance of polyvinyl alcohol water-based paint through temperature rise secondary curing Download PDF

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CN111574893B
CN111574893B CN202010483302.4A CN202010483302A CN111574893B CN 111574893 B CN111574893 B CN 111574893B CN 202010483302 A CN202010483302 A CN 202010483302A CN 111574893 B CN111574893 B CN 111574893B
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coating
polyvinyl alcohol
mixture
placing
metal
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CN111574893A (en
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吴航
张俊波
王福会
耿树江
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Northeastern University China
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    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • 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
    • C09D129/00—Coating compositions based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an alcohol, ether, aldehydo, ketonic, acetal, or ketal radical; Coating compositions based on hydrolysed polymers of esters of unsaturated alcohols with saturated carboxylic acids; Coating compositions based on derivatives of such polymers
    • C09D129/02—Homopolymers or copolymers of unsaturated alcohols
    • C09D129/04—Polyvinyl alcohol; Partially hydrolysed homopolymers or copolymers of esters of unsaturated alcohols with saturated carboxylic acids
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D3/00—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials
    • B05D3/002—Pretreatement
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D5/00—Processes for applying liquids or other fluent materials to surfaces to obtain special surface effects, finishes or structures
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
    • B05D7/14—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials to metal, e.g. car bodies
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
    • B05D7/50—Multilayers
    • B05D7/52—Two layers
    • B05D7/54—No clear coat specified
    • B05D7/542—No clear coat specified the two layers being cured or baked together
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
    • B05D7/50—Multilayers
    • B05D7/52—Two layers
    • B05D7/54—No clear coat specified
    • B05D7/544—No clear coat specified the first layer is let to dry at least partially before applying the second layer
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
    • B05D7/50—Multilayers
    • B05D7/56—Three layers or more
    • B05D7/58—No clear coat specified
    • B05D7/582—No clear coat specified all layers being cured or baked together
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
    • B05D7/50—Multilayers
    • B05D7/56—Three layers or more
    • B05D7/58—No clear coat specified
    • B05D7/584—No clear coat specified at least some layers being let to dry, at least partially, before applying the next layer
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • 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
    • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
    • C09D5/08—Anti-corrosive paints
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • 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
    • C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
    • C09D7/40—Additives
    • C09D7/60—Additives non-macromolecular
    • C09D7/61—Additives non-macromolecular inorganic
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/32—Phosphorus-containing compounds
    • C08K2003/321—Phosphates
    • C08K2003/325—Calcium, strontium or barium phosphate

Abstract

A method for improving corrosion resistance of a polyvinyl alcohol water-based paint by heating and secondary curing belongs to the technical field of paints and adopts graphene, phosphorus powder and SiO2And adding SiC serving as mixed filler into the polyvinyl alcohol solution, and carrying out secondary curing by heating to stabilize the coating. According to the invention, the high thermal conductivity of the nano-filler is utilized to improve the secondary curing efficiency, effectively reduce the binding sites of water molecules in the coating, and greatly reduce the water delivery channel formed by polar groups in the coating, thereby improving the adhesion and corrosion resistance of the coating; meanwhile, the secondary curing can firmly coat, enhance the binding property of the mixed filler, further promote the graphene to play a barrier role and promote phosphorus and SiO2The SiC and the coating improve the crosslinking density of the coating to form a stable and compact three-dimensional network structure, so that the compactness of the coating is improved, and a better anti-corrosion effect is achieved; the method is safe and environment-friendly, is simple to operate and has better realizability.

Description

Method for improving corrosion resistance of polyvinyl alcohol water-based paint through temperature rise secondary curing
Technical Field
The invention belongs to the technical field of coatings, and particularly relates to a method for improving corrosion resistance of a polyvinyl alcohol water-based coating by heating and secondary curing.
Background
The most common and effective method for preventing metal corrosion is to apply anticorrosive coatings, and the traditional solvent-based anticorrosive coatings contain a large amount of toxic volatile organic compounds, which seriously harm the health of people, so that the development of water-based coatings without or without volatile toxic substances is urgent. The water-based paint takes water as a solvent or a dispersant, and a film-forming substance of the water-based paint contains polar groups such as hydroxyl groups and the like or artificially grafted polar groups so as to improve the solubility or the dispersibility of the water-based paint in water. However, in the film forming process, along with the volatilization of moisture, polar groups are continuously close due to similar compatibility to form a polar water delivery channel, so that the permeation resistance of the coating is reduced. At present, a great deal of experimental research is carried out at home and abroad to solve the problem of poor permeation resistance of the environment-friendly water-based paint. Among them, some researches mainly focus on adding a crosslinking agent into a water-based paint, and increasing the crosslinking density of a coating by utilizing the crosslinking reaction (including physical crosslinking and chemical crosslinking) of the crosslinking agent and a film-forming substance, thereby improving the anti-permeability of the coating. The other research mainly focuses on adding a barrier nano material into the coating, adding substances such as nano particles, nano fibers, laminar nano materials and the like into the water-based coating, generating a labyrinth effect, and prolonging the transmission path of a corrosive medium in the coating so as to improve the corrosion protection performance of the coating.
In the prior art, the effect of adding the barrier nano material on improving the corrosion resistance of the water-based paint is limited. On one hand, the compatibility of the hydrophobic nano filler and the water-based paint is poor, the interface of the nano filler and the water-based paint resin is often the weakest place, and corrosive media easily permeate to the surface of the metal matrix through the interface between the filler and the organic resin, so that the corrosion is caused. On the other hand, the compatibility between the hydrophilic nano filler and the water-based paint is greatly improved compared with the hydrophobicity, but the hydrophilic filler often contains or is artificially introduced with a large number of polar groups, so that the compatibility between the hydrophilic filler and the resin is improved, and simultaneously, a water delivery channel formed by a large number of polar groups is introduced, and the corrosion resistance is weakened. Thus, the improvement of corrosion resistance of aqueous coatings still faces major challenges.
Disclosure of Invention
In order to solve the technical problems, the invention provides a method for improving the corrosion resistance of a polyvinyl alcohol water-based coating by heating and secondary curing, which is characterized in that a nano filler is added, the high thermal conductivity of the nano filler is utilized, the secondary curing efficiency is improved, a dehydration reaction is rapidly carried out, unreacted hydroxyl in the coating is eliminated, and a hydrophobic carbon-carbon double bond or carbon-oxygen double bond is formed, so that the binding sites of water molecules in the coating are effectively reduced, a water delivery channel formed by polar groups in the coating is greatly reduced, and the adhesion and corrosion resistance of the coating are improved; meanwhile, the secondary curing can further promote the graphene to play a barrier role, and phosphorus and SiO2And SiC exerts its effect of increasing the crosslink density of the coating. The specific technical scheme is as follows:
a method for improving corrosion resistance of a polyvinyl alcohol water-based paint by heating secondary curing comprises the following steps:
step 1, dissolving a base material:
according to the weight percentage of polyvinyl alcohol: 100 parts of deionized water: (1-20000), mixing polyvinyl alcohol and deionized water, placing the mixture in a container, adding a polytetrafluoroethylene rotor, continuously stirring the mixture in a heat collection type constant-temperature heating magnetic stirrer at room temperature to 95 ℃ until the polyvinyl alcohol is fully dissolved, slowly cooling the mixture to room temperature, and finally filtering the mixture by using a filter screen to remove impurities in the solution to obtain pure polyvinyl alcohol solution;
step 2, mixing the filler:
according to the graphene: phosphorus powder: SiO 22: SiC ═ 3-7): (1-5): (0.01-0.5): (0.1-5) weighing graphene, phosphorus powder and SiO in percentage by mass2And SiC, and mixing uniformly to prepare a mixed filler;
step 3, preparing the coating:
according to the weight percentage of polyvinyl alcohol: mixed filler 100: (0.01-1), adding a mixed filler into the polyvinyl alcohol solution, uniformly stirring, and finally placing the solution in an ultrasonic cleaner for defoaming treatment for 1-3 hours to obtain a polyvinyl alcohol coating;
step 4, coating:
coating polyvinyl alcohol paint on a metal substrate, wherein the coating process of the paint comprises the following steps:
(1) pretreatment: carrying out sand blasting treatment on a metal matrix to be coated by corundum or polishing treatment by SiC abrasive paper to remove rust and impurities on the surface of the metal matrix, then scrubbing the metal matrix by adopting a mixed solution of absolute ethyl alcohol and acetone to remove oil stains on the surface, airing, and finally placing the metal matrix into a dryer for storage or direct use;
(2) coating: taking out the metal substrate, coating polyvinyl alcohol paint on the surface of the metal substrate, wherein the coating thickness is 10-150 mu m each time, coating for 1-5 times, and after the surface of the coating coated on the previous time is dried for 10 hours each time, performing the next coating procedure to ensure that the coating directions of two adjacent times are mutually vertical, so that bubbles generated in the coating process are avoided, and the total thickness of the coating is controlled by the coating times to obtain coating metal;
step 5, primary curing:
placing the coating metal at room temperature, and curing for 24-48 h;
and 6, secondary curing:
heating an oven to 170-230 ℃ in advance, keeping the temperature constant for 10min, then placing the coating metal cured at room temperature into the oven, and performing secondary curing to form a film, wherein the curing temperature is 170-230 ℃, and the curing time is 1-5 h;
and (4) immediately taking out the sample after solidification, placing the sample in a cold room at 5-15 ℃, and rapidly cooling.
In the step 1, the alcoholysis degree of the polyvinyl alcohol is 78-98%;
in the step 1, the mass fraction ratio of the polyvinyl alcohol to the deionized water is preferably polyvinyl alcohol: 100 parts of deionized water: (1-10000);
in the step 2, the thermal conductivity of the graphene is (4840 +/-440) - (5300 +/-480) W/mK, and the graphene is one or a mixture of two of single-layer graphene and multi-layer graphene;
in the step 2, the size of the graphene is 900-2000 nm, the particle size of the phosphorus powder is 0.1-0.5 nm, and SiO is added2The granularity of the SiC is 1-50 nm, and the granularity of the SiC is 10-20 nm;
in the step 3, the stirring time is 2-3 h;
in the step 4(1), the volume ratio of the absolute ethyl alcohol to the acetone is 1: 1 or 1: 2;
in the step 4(2), the coating is applied by brushing, spraying, dripping or dipping.
Compared with the prior art, the method for improving the corrosion resistance of the polyvinyl alcohol water-based paint by heating and secondary curing has the beneficial effects that:
firstly, nano-scale mixed filler (graphene, phosphorus powder and SiO) is added in the method2SiC) and combining with secondary curing treatment, the high thermal conductivity of the nano filler is utilized to improve the secondary curing efficiency, so that the coating can be quickly subjected to dehydration reaction, unreacted hydroxyl in the coating is eliminated, and hydrophobic carbon-carbon double bonds or carbon-carbon double bonds are formedThe oxygen double bonds effectively reduce the binding sites of water molecules in the coating, and greatly reduce a water delivery channel formed by polar groups in the coating, thereby improving the adhesion and corrosion resistance of the coating;
secondly, the secondary curing can firmly coat, enhance the binding property of the mixed filler, further promote the graphene to play a barrier role and promote phosphorus and SiO2And SiC exerts the effect of improving the crosslinking density of the coating to form a stable and compact three-dimensional network structure, so that the compactness of the coating is improved, and a better anti-corrosion effect is achieved.
And the graphene has excellent thermal conductivity, can effectively improve the heat utilization rate of secondary curing, reduces the curing temperature and time, and saves the cost.
Fourthly, graphene with the size of 900-2000 nm is adopted, the barrier property and the anti-permeability of lamellar graphene can be effectively utilized, and 0.1-0.5 nm of phosphorus powder and 1-50 nm of SiO are combined2The SiC with the particle size of 10-20 nm can form a compact network structure with complex paths in the coating layer due to different particle sizes of all components, so that infiltration and erosion are prevented, and the barrier property is further improved.
The method for improving the corrosion resistance of the polyvinyl alcohol water-based paint by heating and secondary curing does not contain toxic chemical reagents, does not cause pollution to the environment, and is safe and environment-friendly.
The method has the advantages of simple operation, stable coating quality, more than 98% of qualified rate, economic and practical process and better realizability.
And seventhly, through detection, compared with the coating formed by the common method, the contact angle of the coating can be improved by 4-7 times, the water absorption of the coating can be reduced by 60-95%, the strength of the coating can be improved by 7-45%, the impact resistance can be improved by 12-50%, and the salt spray resistant time of the coating can be improved by 5-12 times.
Detailed Description
The present invention will be further described with reference to specific examples, but the present invention is not limited to these examples.
Example 1
A method for improving corrosion resistance of a polyvinyl alcohol water-based paint by heating secondary curing comprises the following steps:
step 1, dissolving a base material:
adding 100g of polyvinyl alcohol with alcoholysis degree of 98% into 20000g of deionized water, placing the mixture in a flask, adding a polytetrafluoroethylene rotor, continuously stirring the mixture in a heat collection type constant-temperature heating magnetic stirrer at room temperature to 95 ℃ for 24 hours until the polyvinyl alcohol is fully dissolved, slowly cooling the mixture to room temperature, and finally filtering the mixture by using a 400-mesh filter screen to remove impurities in the solution to obtain pure polyvinyl alcohol solution;
step 2, mixing the filler:
3g of graphene, 1g of phosphorus powder and 0.01g of SiO are weighed respectively20.1g of SiC, and uniformly mixing to prepare a mixed filler; the size of the graphene is 900-2000 nm, the particle size of the phosphorus powder is 0.1-0.5 nm, and the particle size of the SiO powder is2The granularity of the SiC is 1-50 nm, and the granularity of the SiC is 10-20 nm; the graphene is single-layer graphene, and the thermal conductivity is 5012W/mK;
step 3, preparing the coating:
adding 0.01g of mixed filler into a polyvinyl alcohol solution, stirring for 2 hours, and finally placing the mixture into an ultrasonic cleaner for defoaming treatment for 1 hour to obtain a polyvinyl alcohol coating;
step 4, coating:
coating polyvinyl alcohol paint on a metal substrate, wherein the coating process of the paint comprises the following steps:
(1) pretreatment: carrying out sand blasting treatment on a metal matrix to be coated by corundum or polishing treatment by SiC abrasive paper to remove rust and impurities on the surface of the metal matrix, then scrubbing the metal matrix by adopting a mixed solution of absolute ethyl alcohol and acetone in a volume ratio of 1: 1, removing oil stains on the surface, airing, and finally putting the metal matrix into a dryer for later use;
(2) coating: taking out the metal matrix, spraying polyvinyl alcohol coating on the surface of the metal matrix by using a spray gun, wherein the coating thickness is 10-30 mu m each time, and coating for 3 times to obtain coating metal;
step 5, primary curing:
placing the coating metal at room temperature, and curing for 24 h;
and 6, secondary curing:
heating an oven to 230 ℃ in advance, keeping the temperature constant for 10min, placing the coating metal cured at room temperature into the oven, and performing secondary curing to form a film, wherein the curing temperature is 230 ℃ and the curing time is 5 h; and (4) immediately taking out the sample after solidification, placing the sample in a cold room at 5-15 ℃, and rapidly cooling.
To verify the performance of the corrosion protection coating of this example, comparative experiments were conducted as follows:
preparing a common polyvinyl alcohol coating: (1) mixing polyvinyl alcohol and deionized water according to the same mass fraction ratio as that in the step 1 of the embodiment, placing the mixture into a flask, adding a polytetrafluoroethylene rotor, continuously stirring the mixture in a heat collection type constant-temperature heating magnetic stirrer at room temperature to 95 ℃ for 24 hours, slowly cooling the mixture to room temperature, and filtering the mixture by using a 400-mesh filter screen to remove impurities in the solution to obtain a polyvinyl alcohol solution; (2) placing the mixture in an ultrasonic cleaner for defoaming for 1h to obtain polyvinyl alcohol coating; (3) the polyvinyl alcohol paint for verification was coated on a metal substrate in the same manner as in step 4 of this example to obtain a coated metal; (4) the coating metal was left at room temperature and cured for 24h to make a comparative coating.
When the anticorrosive coating and the comparative coating are detected, the contact angle of the anticorrosive coating is improved by 4 times, the water absorption of the coating is reduced by 60%, the strength of the coating is improved by 10%, the impact resistance is improved by 15%, and the salt spray resistant time of the coating is improved by 5 times.
Example 2
A method for improving corrosion resistance of a polyvinyl alcohol water-based paint by heating secondary curing comprises the following steps:
step 1, dissolving a base material:
adding 15000g of deionized water into 100g of polyvinyl alcohol with alcoholysis degree of 98%, placing in a flask, adding a polytetrafluoroethylene rotor, continuously stirring for 24h in a heat collection type constant-temperature heating magnetic stirrer at room temperature to 95 ℃ until the polyvinyl alcohol is fully dissolved, slowly cooling to room temperature, and finally filtering by using a 400-mesh filter screen to remove impurities in the solution to obtain pure polyvinyl alcohol solution;
step 2, mixing the filler:
respectively weighing 7g of graphene, 5g of phosphorus powder and 0.5g of SiO25g of SiC, and uniformly mixing to prepare a mixed filler; the size of the graphene is 900-2000 nm, the particle size of the phosphorus powder is 0.1-0.5 nm, and the particle size of the SiO powder is2The granularity of the SiC is 1-50 nm, and the granularity of the SiC is 10-20 nm; the graphene is single-layer graphene, and the thermal conductivity is 5012W/mK;
step 3, preparing the coating:
adding 1g of mixed filler into a polyvinyl alcohol solution, stirring for 3 hours, and finally placing the mixture into an ultrasonic cleaner for defoaming treatment for 3 hours to obtain a polyvinyl alcohol coating;
step 4, coating:
coating polyvinyl alcohol paint on a metal substrate, wherein the coating process of the paint comprises the following steps:
(2) pretreatment: carrying out sand blasting treatment on a metal matrix to be coated by corundum or polishing treatment by SiC abrasive paper to remove rust and impurities on the surface of the metal matrix, then scrubbing the metal matrix by adopting a mixed solution of absolute ethyl alcohol and acetone in a volume ratio of 1: 2, removing oil stains on the surface, airing, and finally putting the metal matrix into a dryer for later use;
(2) coating: taking out the metal matrix, spraying polyvinyl alcohol coating on the surface of the metal matrix by using a spray gun, wherein the coating thickness is 40-60 mu m each time, and coating for 3 times to obtain coating metal;
step 5, primary curing:
placing the coating metal at room temperature, and curing for 24 h;
and 6, secondary curing:
and (3) heating the oven to 190 ℃ in advance, keeping the temperature constant for 10min, then placing the coating metal solidified at room temperature into the oven, carrying out secondary solidification to form a film, wherein the solidification temperature is 190 ℃, the solidification time is 3h, and after solidification is finished, immediately taking out the sample, placing the sample into a 5-15 ℃ cold room, and rapidly cooling.
To verify the performance of the corrosion protection coating of this example, comparative experiments were conducted as follows:
preparing a common polyvinyl alcohol coating: (1) mixing polyvinyl alcohol and deionized water according to the same mass fraction ratio as that in the step 1 of the embodiment, placing the mixture into a flask, adding a polytetrafluoroethylene rotor, continuously stirring the mixture in a heat collection type constant-temperature heating magnetic stirrer at room temperature to 95 ℃ for 24 hours, slowly cooling the mixture to room temperature, and filtering the mixture by using a 400-mesh filter screen to remove impurities in the solution to obtain a polyvinyl alcohol solution; (2) placing the mixture in an ultrasonic cleaner for defoaming treatment for 3 hours to obtain polyvinyl alcohol coating; (3) the polyvinyl alcohol paint for verification was coated on a metal substrate in the same manner as in step 4 of this example to obtain a coated metal; (4) the coating metal was left at room temperature and cured for 24h to make a comparative coating.
When the anticorrosive coating and the comparative coating are detected, the contact angle of the anticorrosive coating is improved by 7 times, the water absorption of the coating is reduced by 80%, the strength of the coating is improved by 40%, the impact resistance is improved by 45%, and the salt spray resistant time of the coating is improved by 11 times.
Example 3
A method for improving corrosion resistance of a polyvinyl alcohol water-based paint by heating secondary curing comprises the following steps:
step 1, dissolving a base material:
adding 10000g of deionized water into 100g of polyvinyl alcohol with alcoholysis degree of 98%, placing the mixture in a flask, adding a polytetrafluoroethylene rotor, continuously stirring the mixture in a heat collection type constant-temperature heating magnetic stirrer at room temperature to 95 ℃ for 24 hours until the polyvinyl alcohol is fully dissolved, slowly cooling the mixture to room temperature, and finally filtering the mixture by using a 400-mesh filter screen to remove impurities in the solution to obtain pure polyvinyl alcohol solution;
step 2, mixing the filler:
respectively weighing 5g of graphene, 3g of phosphorus powder and 0.2g of SiO20.5g of SiC, and mixing uniformly to prepare a mixed filler; the size of the graphene is 900-2000 nm, the particle size of the phosphorus powder is 0.1-0.5 nm, and the particle size of the SiO powder is2The granularity of the SiC is 1-50 nm, and the granularity of the SiC is 10-20 nm; the graphene is single-layer graphene, and the thermal conductivity is 5012W/mK;
step 3, preparing the coating:
adding 0.5g of mixed filler into the polyvinyl alcohol solution, stirring for 2.5 hours, and finally placing the mixture into an ultrasonic cleaner for defoaming treatment for 2.5 hours to obtain a polyvinyl alcohol coating;
step 4, coating:
coating polyvinyl alcohol paint on a metal substrate, wherein the coating process of the paint comprises the following steps:
(3) pretreatment: carrying out sand blasting treatment on a metal matrix to be coated by corundum or polishing treatment by SiC abrasive paper to remove rust and impurities on the surface of the metal matrix, then scrubbing the metal matrix by adopting a mixed solution of absolute ethyl alcohol and acetone in a volume ratio of 1: 2, removing oil stains on the surface, airing, and finally putting the metal matrix into a dryer for later use;
(2) coating: taking out the metal matrix, spraying polyvinyl alcohol coating on the surface of the metal matrix by using a spray gun, wherein the coating thickness is 10-30 mu m each time, and coating for 5 times to obtain coating metal;
step 5, primary curing:
placing the coating metal at room temperature, and curing for 24 h;
and 6, secondary curing:
and (3) heating the oven to 210 ℃ in advance, keeping the temperature constant for 10min, then placing the coating metal solidified at room temperature into the oven, carrying out secondary solidification to form a film, wherein the solidification temperature is 210 ℃, the solidification time is 2h, immediately taking out the sample after solidification, placing the sample into a 5-15 ℃ cold room, and rapidly cooling the sample.
To verify the performance of the corrosion protection coating of this example, comparative experiments were conducted as follows:
preparing a common polyvinyl alcohol coating: (1) mixing polyvinyl alcohol and deionized water according to the same mass fraction ratio as that in the step 1 of the embodiment, placing the mixture into a flask, adding a polytetrafluoroethylene rotor, continuously stirring the mixture in a heat collection type constant-temperature heating magnetic stirrer at room temperature to 95 ℃ for 24 hours, slowly cooling the mixture to room temperature, and filtering the mixture by using a 400-mesh filter screen to remove impurities in the solution to obtain a polyvinyl alcohol solution; (2) placing the mixture in an ultrasonic cleaner for defoaming for 2.5 hours to obtain polyvinyl alcohol coating; (3) the polyvinyl alcohol paint for verification was coated on a metal substrate in the same manner as in step 4 of this example to obtain a coated metal; (4) the coating metal was left at room temperature and cured for 24h to make a comparative coating.
When the anticorrosive coating and the comparative coating are detected, the contact angle of the anticorrosive coating is improved by 5 times, the water absorption of the coating is reduced by 70%, the strength of the coating is improved by 45%, the impact resistance is improved by 50%, and the salt spray resistant time of the coating is improved by 9 times.
Example 4
A method for improving corrosion resistance of a polyvinyl alcohol water-based paint by heating secondary curing comprises the following steps:
step 1, dissolving a base material:
adding 15000g of deionized water into 100g of polyvinyl alcohol with alcoholysis degree of 87%, placing in a flask, adding a polytetrafluoroethylene rotor, continuously stirring for 24h in a heat collection type constant-temperature heating magnetic stirrer at room temperature to 95 ℃ until the polyvinyl alcohol is fully dissolved, slowly cooling to room temperature, and finally filtering by using a 400-mesh filter screen to remove impurities in the solution to obtain pure polyvinyl alcohol solution;
step 2, mixing the filler:
3g of graphene, 1g of phosphorus powder and 0.01g of SiO are weighed respectively20.1g of SiC, and uniformly mixing to prepare a mixed filler; the size of the graphene is 900-2000 nm, the particle size of the phosphorus powder is 0.1-0.5 nm, and the particle size of the SiO powder is2The granularity of the SiC is 1-50 nm, and the granularity of the SiC is 10-20 nm; the graphene is single-layer graphene, and the thermal conductivity is 5012W/mK;
step 3, preparing the coating:
adding 0.1g of mixed filler into a polyvinyl alcohol solution, stirring for 2 hours, and finally placing the mixture into an ultrasonic cleaner for defoaming treatment for 3 hours to obtain a polyvinyl alcohol coating;
step 4, coating:
coating polyvinyl alcohol paint on a metal substrate, wherein the coating process of the paint comprises the following steps:
(4) pretreatment: carrying out sand blasting treatment on a metal matrix to be coated by corundum or polishing treatment by SiC abrasive paper to remove rust and impurities on the surface of the metal matrix, then scrubbing the metal matrix by adopting a mixed solution of absolute ethyl alcohol and acetone in a volume ratio of 1: 1, removing oil stains on the surface, airing, and finally putting the metal matrix into a dryer for later use;
(2) coating: taking out the metal matrix, spraying polyvinyl alcohol coating on the surface of the metal matrix by using a spray gun, wherein the coating thickness is 60-80 mu m each time, and coating for 2 times to obtain coating metal;
step 5, primary curing:
placing the coating metal at room temperature, and curing for 24 h;
and 6, secondary curing:
and (3) heating the oven to 220 ℃ in advance, keeping the temperature constant for 10min, then placing the coating metal solidified at room temperature into the oven, carrying out secondary solidification to form a film, wherein the solidification temperature is 220 ℃, the solidification time is 4h, immediately taking out the sample after solidification, placing the sample into a 5-15 ℃ cold room, and rapidly cooling.
To verify the performance of the corrosion protection coating of this example, comparative experiments were conducted as follows:
preparing a common polyvinyl alcohol coating: (1) mixing polyvinyl alcohol and deionized water according to the same mass fraction ratio as that in the step 1 of the embodiment, placing the mixture into a flask, adding a polytetrafluoroethylene rotor, continuously stirring the mixture in a heat collection type constant-temperature heating magnetic stirrer at room temperature to 95 ℃ for 24 hours, slowly cooling the mixture to room temperature, and filtering the mixture by using a 400-mesh filter screen to remove impurities in the solution to obtain a polyvinyl alcohol solution; (2) placing the mixture in an ultrasonic cleaner for defoaming treatment for 3 hours to obtain polyvinyl alcohol coating; (3) the polyvinyl alcohol paint for verification was coated on a metal substrate in the same manner as in step 4 of this example to obtain a coated metal; (4) the coating metal was left at room temperature and cured for 24h to make a comparative coating.
When the anticorrosive coating and the comparative coating are detected, the contact angle of the anticorrosive coating is improved by 5 times, the water absorption of the coating is reduced by 75%, the strength of the coating is improved by 30%, the impact resistance is improved by 40%, and the salt spray resistant time of the coating is improved by 7 times.
Example 5
A method for improving corrosion resistance of a polyvinyl alcohol water-based paint by heating secondary curing comprises the following steps:
step 1, dissolving a base material:
adding 1000g of deionized water into 100g of polyvinyl alcohol with alcoholysis degree of 87%, placing the polyvinyl alcohol into a flask, adding a polytetrafluoroethylene rotor, continuously stirring the polyvinyl alcohol in a heat collection type constant-temperature heating magnetic stirrer at room temperature to 95 ℃ for 24 hours until the polyvinyl alcohol is fully dissolved, slowly cooling the polyvinyl alcohol to room temperature, and finally filtering the polyvinyl alcohol solution by using a 400-mesh filter screen to remove impurities in the solution to obtain pure polyvinyl alcohol solution;
step 2, mixing the filler:
respectively weighing 7g of graphene, 5g of phosphorus powder and 0.5g of SiO25g of SiC, and uniformly mixing to prepare a mixed filler; the size of the graphene is 900-2000 nm, the particle size of the phosphorus powder is 0.1-0.5 nm, and the particle size of the SiO powder is2The granularity of the SiC is 1-50 nm, and the granularity of the SiC is 10-20 nm; the graphene is single-layer graphene, and the thermal conductivity is 5012W/mK;
step 3, preparing the coating:
adding 1g of mixed filler into a polyvinyl alcohol solution, stirring for 3 hours, and finally placing the mixture into an ultrasonic cleaner for defoaming treatment for 3 hours to obtain a polyvinyl alcohol coating;
step 4, coating:
coating polyvinyl alcohol paint on a metal substrate, wherein the coating process of the paint comprises the following steps:
(5) pretreatment: carrying out sand blasting treatment on a metal matrix to be coated by corundum or polishing treatment by SiC abrasive paper to remove rust and impurities on the surface of the metal matrix, then scrubbing the metal matrix by adopting a mixed solution of absolute ethyl alcohol and acetone in a volume ratio of 1: 1, removing oil stains on the surface, airing, and finally putting the metal matrix into a dryer for later use;
(2) coating: taking out the metal matrix, spraying polyvinyl alcohol coating on the surface of the metal matrix by using a spray gun, wherein the coating thickness is 80-100 mu m each time, and coating for 2 times to obtain coating metal;
step 5, primary curing:
placing the coating metal at room temperature, and curing for 24 h;
and 6, secondary curing:
and (3) heating the oven to 190 ℃ in advance, keeping the temperature constant for 10min, then placing the coating metal solidified at room temperature into the oven, carrying out secondary solidification to form a film, wherein the solidification temperature is 190 ℃, the solidification time is 2h, immediately taking out the sample after solidification, placing the sample into a 5-15 ℃ cold room, and rapidly cooling the sample.
To verify the performance of the corrosion protection coating of this example, comparative experiments were conducted as follows:
preparing a common polyvinyl alcohol coating: (1) mixing polyvinyl alcohol and deionized water according to the same mass fraction ratio as that in the step 1 of the embodiment, placing the mixture into a flask, adding a polytetrafluoroethylene rotor, continuously stirring the mixture in a heat collection type constant-temperature heating magnetic stirrer at room temperature to 95 ℃ for 24 hours, slowly cooling the mixture to room temperature, and filtering the mixture by using a 400-mesh filter screen to remove impurities in the solution to obtain a polyvinyl alcohol solution; (2) placing the mixture in an ultrasonic cleaner for defoaming treatment for 3 hours to obtain polyvinyl alcohol coating; (3) the polyvinyl alcohol paint for verification was coated on a metal substrate in the same manner as in step 4 of this example to obtain a coated metal; (4) the coating metal was left at room temperature and cured for 24h to make a comparative coating.
When the anticorrosive coating and the comparative coating are detected, the contact angle of the anticorrosive coating is improved by 6 times, the water absorption of the coating is reduced by 80%, the strength of the coating is improved by 35%, the impact resistance is improved by 45%, and the salt spray resistant time of the coating is improved by 8 times.
Example 6
A method for improving corrosion resistance of a polyvinyl alcohol water-based paint by heating secondary curing comprises the following steps:
step 1, dissolving a base material:
adding 5000g of deionized water into 100g of polyvinyl alcohol with alcoholysis degree of 87%, placing the mixture in a flask, adding a polytetrafluoroethylene rotor, continuously stirring the mixture in a heat collection type constant-temperature heating magnetic stirrer at room temperature to 95 ℃ for 24 hours until the polyvinyl alcohol is fully dissolved, slowly cooling the mixture to room temperature, and finally filtering the mixture by using a 400-mesh filter screen to remove impurities in the solution to obtain pure polyvinyl alcohol solution;
step 2, mixing the filler:
respectively weighing 4g of graphene, 2g of phosphorus powder and 0.09g of SiO20.7g of SiC, and mixing uniformly to prepare a mixed filler; the size of the graphene is 900-2000 nm, the particle size of the phosphorus powder is 0.1-0.5 nm, and the particle size of the SiO powder is2Has a particle size of 1 to 50nm and SiC having a particle size of10-20 nm; the graphene is single-layer graphene, and the thermal conductivity is 5012W/mK;
step 3, preparing the coating:
adding 0.3g of mixed filler into the polyvinyl alcohol solution, stirring for 2.5 hours, and finally placing the mixture in an ultrasonic cleaner for defoaming treatment for 1 hour to obtain a polyvinyl alcohol coating;
step 4, coating:
coating polyvinyl alcohol paint on a metal substrate, wherein the coating process of the paint comprises the following steps:
(6) pretreatment: carrying out sand blasting treatment on a metal matrix to be coated by corundum or polishing treatment by SiC abrasive paper to remove rust and impurities on the surface of the metal matrix, then scrubbing the metal matrix by adopting a mixed solution of absolute ethyl alcohol and acetone in a volume ratio of 1: 2, removing oil stains on the surface, airing, and finally putting the metal matrix into a dryer for later use;
(2) coating: taking out the metal substrate, spraying polyvinyl alcohol coating on the surface of the metal substrate by a spray gun, wherein the coating thickness is 100-150 mu m each time, and coating for 1 time to obtain coating metal;
step 5, primary curing:
placing the coating metal at room temperature, and curing for 24 h;
and 6, secondary curing:
and (3) heating the oven to 200 ℃ in advance, keeping the temperature constant for 10min, then placing the coating metal solidified at room temperature into the oven, carrying out secondary solidification to form a film, wherein the solidification temperature is 200 ℃, the solidification time is 2h, immediately taking out the sample after solidification, placing the sample into a cold room at 5-15 ℃, and rapidly cooling.
To verify the performance of the corrosion protection coating of this example, comparative experiments were conducted as follows:
preparing a common polyvinyl alcohol coating: (1) mixing polyvinyl alcohol and deionized water according to the same mass fraction ratio as that in the step 1 of the embodiment, placing the mixture into a flask, adding a polytetrafluoroethylene rotor, continuously stirring the mixture in a heat collection type constant-temperature heating magnetic stirrer at room temperature to 95 ℃ for 24 hours, slowly cooling the mixture to room temperature, and filtering the mixture by using a 400-mesh filter screen to remove impurities in the solution to obtain a polyvinyl alcohol solution; (2) placing the mixture in an ultrasonic cleaner for defoaming for 1h to obtain polyvinyl alcohol coating; (3) the polyvinyl alcohol paint for verification was coated on a metal substrate in the same manner as in step 4 of this example to obtain a coated metal; (4) the coating metal was left at room temperature and cured for 24h to make a comparative coating.
When the anticorrosive coating and the comparative coating are detected, the contact angle of the anticorrosive coating is improved by 5 times, the water absorption of the coating is reduced by 70%, the strength of the coating is improved by 30%, the impact resistance is improved by 35%, and the salt spray resistant time of the coating is improved by 7 times.
Example 7
A method for improving corrosion resistance of a polyvinyl alcohol water-based paint by heating secondary curing comprises the following steps:
step 1, dissolving a base material:
adding 100g of polyvinyl alcohol with alcoholysis degree of 78% into 8000g of deionized water, placing in a flask, adding a polytetrafluoroethylene rotor, continuously stirring for 24h in a heat collection type constant-temperature heating magnetic stirrer at room temperature to 95 ℃ until the polyvinyl alcohol is fully dissolved, slowly cooling to room temperature, and finally filtering by using a 400-mesh filter screen to remove impurities in the solution to obtain pure polyvinyl alcohol solution;
step 2, mixing the filler:
3g of graphene, 1g of phosphorus powder and 0.01g of SiO are weighed respectively20.1g of SiC, and uniformly mixing to prepare a mixed filler; the size of the graphene is 900-2000 nm, the particle size of the phosphorus powder is 0.1-0.5 nm, and the particle size of the SiO powder is2The granularity of the SiC is 1-50 nm, and the granularity of the SiC is 10-20 nm; the graphene is single-layer graphene, and the thermal conductivity is 5012W/mK;
step 3, preparing the coating:
adding 0.01g of mixed filler into a polyvinyl alcohol solution, stirring for 2 hours, and finally placing the mixture into an ultrasonic cleaner for defoaming treatment for 2 hours to obtain a polyvinyl alcohol coating;
step 4, coating:
coating polyvinyl alcohol paint on a metal substrate, wherein the coating process of the paint comprises the following steps:
(7) pretreatment: carrying out sand blasting treatment on a metal matrix to be coated by corundum or polishing treatment by SiC abrasive paper to remove rust and impurities on the surface of the metal matrix, then scrubbing the metal matrix by adopting a mixed solution of absolute ethyl alcohol and acetone in a volume ratio of 1: 2, removing oil stains on the surface, airing, and finally putting the metal matrix into a dryer for later use;
(2) coating: taking out the metal matrix, spraying polyvinyl alcohol coating on the surface of the metal matrix by using a spray gun, wherein the coating thickness is 20-40 mu m each time, and coating for 4 times to obtain coating metal;
step 5, primary curing:
placing the coating metal at room temperature, and curing for 24 h;
and 6, secondary curing:
and (3) heating the oven to 180 ℃ in advance, keeping the temperature constant for 10min, then placing the coating metal solidified at room temperature into the oven, carrying out secondary solidification to form a film, wherein the solidification temperature is 180 ℃, the solidification time is 3h, immediately taking out the sample after solidification, placing the sample into a 5-15 ℃ cold room, and rapidly cooling.
To verify the performance of the corrosion protection coating of this example, comparative experiments were conducted as follows:
preparing a common polyvinyl alcohol coating: (1) mixing polyvinyl alcohol and deionized water according to the same mass fraction ratio as that in the step 1 of the embodiment, placing the mixture into a flask, adding a polytetrafluoroethylene rotor, continuously stirring the mixture in a heat collection type constant-temperature heating magnetic stirrer at room temperature to 95 ℃ for 24 hours, slowly cooling the mixture to room temperature, and filtering the mixture by using a 400-mesh filter screen to remove impurities in the solution to obtain a polyvinyl alcohol solution; (2) placing the mixture in an ultrasonic cleaner for defoaming for 2 hours to obtain polyvinyl alcohol coating; (3) the polyvinyl alcohol paint for verification was coated on a metal substrate in the same manner as in step 4 of this example to obtain a coated metal; (4) the coating metal was left at room temperature and cured for 24h to make a comparative coating.
When the anticorrosive coating and the comparative coating are detected, the contact angle of the anticorrosive coating is improved by 5 times, the water absorption of the coating is reduced by 70%, the strength of the coating is improved by 20%, the impact resistance is improved by 25%, and the salt spray resistant time of the coating is improved by 7 times.
Example 8
A method for improving corrosion resistance of a polyvinyl alcohol water-based paint by heating secondary curing comprises the following steps:
step 1, dissolving a base material:
adding 5000g of deionized water into 100g of polyvinyl alcohol with alcoholysis degree of 78%, placing the mixture in a flask, adding a polytetrafluoroethylene rotor, continuously stirring the mixture in a heat collection type constant-temperature heating magnetic stirrer at room temperature to 95 ℃ for 24 hours until the polyvinyl alcohol is fully dissolved, slowly cooling the mixture to room temperature, and finally filtering the mixture by using a 400-mesh filter screen to remove impurities in the solution to obtain pure polyvinyl alcohol solution;
step 2, mixing the filler:
respectively weighing 6g of graphene, 4g of phosphorus powder and 0.4g of SiO24g of SiC, and uniformly mixing to prepare a mixed filler; the size of the graphene is 900-2000 nm, the particle size of the phosphorus powder is 0.1-0.5 nm, and the particle size of the SiO powder is2The granularity of the SiC is 1-50 nm, and the granularity of the SiC is 10-20 nm; the graphene is single-layer graphene, and the thermal conductivity is 5012W/mK;
step 3, preparing the coating:
adding 0.8g of mixed filler into the polyvinyl alcohol solution, stirring for 2.5 hours, and finally placing the mixture into an ultrasonic cleaner for defoaming treatment for 2.5 hours to obtain a polyvinyl alcohol coating;
step 4, coating:
coating polyvinyl alcohol paint on a metal substrate, wherein the coating process of the paint comprises the following steps:
(8) pretreatment: carrying out sand blasting treatment on a metal matrix to be coated by corundum or polishing treatment by SiC abrasive paper to remove rust and impurities on the surface of the metal matrix, then scrubbing the metal matrix by adopting a mixed solution of absolute ethyl alcohol and acetone in a volume ratio of 1: 1, removing oil stains on the surface, airing, and finally putting the metal matrix into a dryer for later use;
(2) coating: taking out the metal matrix, spraying polyvinyl alcohol coating on the surface of the metal matrix by using a spray gun, wherein the coating thickness is 80-100 mu m each time, and coating for 3 times to obtain coating metal;
step 5, primary curing:
placing the coating metal at room temperature, and curing for 24 h;
and 6, secondary curing:
and (3) heating the oven to 170 ℃ in advance, keeping the temperature constant for 10min, then placing the coating metal solidified at room temperature into the oven, carrying out secondary solidification to form a film, wherein the solidification temperature is 170 ℃, the solidification time is 1h, immediately taking out the sample after solidification, placing the sample into a 5-15 ℃ cold room, and rapidly cooling.
To verify the performance of the corrosion protection coating of this example, comparative experiments were conducted as follows:
preparing a common polyvinyl alcohol coating: (1) mixing polyvinyl alcohol and deionized water according to the same mass fraction ratio as that in the step 1 of the embodiment, placing the mixture into a flask, adding a polytetrafluoroethylene rotor, continuously stirring the mixture in a heat collection type constant-temperature heating magnetic stirrer at room temperature to 95 ℃ for 24 hours, slowly cooling the mixture to room temperature, and filtering the mixture by using a 400-mesh filter screen to remove impurities in the solution to obtain a polyvinyl alcohol solution; (2) placing the mixture in an ultrasonic cleaner for defoaming for 2.5 hours to obtain polyvinyl alcohol coating; (3) the polyvinyl alcohol paint for verification was coated on a metal substrate in the same manner as in step 4 of this example to obtain a coated metal; (4) the coating metal was left at room temperature and cured for 24h to make a comparative coating.
When the anticorrosive coating and the comparative coating are detected, the contact angle of the anticorrosive coating is improved by 7 times, the water absorption of the coating is reduced by 95%, the strength of the coating is improved by 30%, the impact resistance is improved by 35%, and the salt spray resistant time of the coating is improved by 12 times.
Example 9
A method for improving corrosion resistance of a polyvinyl alcohol water-based paint by heating secondary curing comprises the following steps:
step 1, dissolving a base material:
adding 100g of polyvinyl alcohol with alcoholysis degree of 78% into 7000g of deionized water, placing the mixture in a flask, adding a polytetrafluoroethylene rotor, continuously stirring the mixture in a heat collection type constant-temperature heating magnetic stirrer at room temperature to 95 ℃ for 24 hours until the polyvinyl alcohol is fully dissolved, slowly cooling the mixture to room temperature, and finally filtering the mixture by using a 400-mesh filter screen to remove impurities in the solution to obtain pure polyvinyl alcohol solution;
step 2, mixing the filler:
respectively weighing 5g of graphene, 2g of phosphorus powder and 0.05g of SiO20.4g of SiC, and mixing uniformly to prepare a mixed filler; the size of the graphene is 900-2000 nm, the particle size of the phosphorus powder is 0.1-0.5 nm, and the particle size of the SiO powder is2The granularity of the SiC is 1-50 nm, and the granularity of the SiC is 10-20 nm; the graphene is single-layer graphene, and the thermal conductivity is 5012W/mK;
step 3, preparing the coating:
adding 0.6g of mixed filler into the polyvinyl alcohol solution, stirring for 2.5 hours, and finally placing the mixture in an ultrasonic cleaner for defoaming treatment for 3 hours to obtain a polyvinyl alcohol coating;
step 4, coating:
coating polyvinyl alcohol paint on a metal substrate, wherein the coating process of the paint comprises the following steps:
(9) pretreatment: carrying out sand blasting treatment on a metal matrix to be coated by corundum or polishing treatment by SiC abrasive paper to remove rust and impurities on the surface of the metal matrix, then scrubbing the metal matrix by adopting a mixed solution of absolute ethyl alcohol and acetone in a volume ratio of 1: 1, removing oil stains on the surface, airing, and finally putting the metal matrix into a dryer for later use;
(2) coating: taking out the metal matrix, spraying polyvinyl alcohol coating on the surface of the metal matrix by using a spray gun, wherein the coating thickness is 40-60 mu m each time, and coating for 2 times to obtain coating metal;
step 5, primary curing:
placing the coating metal at room temperature, and curing for 24 h;
and 6, secondary curing:
and (3) heating the oven to 200 ℃ in advance, keeping the temperature constant for 10min, then placing the coating metal solidified at room temperature into the oven, carrying out secondary solidification to form a film, wherein the solidification temperature is 200 ℃, the solidification time is 4h, immediately taking out the sample after solidification, placing the sample into a cold room at 5-15 ℃, and rapidly cooling.
To verify the performance of the corrosion protection coating of this example, comparative experiments were conducted as follows:
preparing a common polyvinyl alcohol coating: (1) mixing polyvinyl alcohol and deionized water according to the same mass fraction ratio as that in the step 1 of the embodiment, placing the mixture into a flask, adding a polytetrafluoroethylene rotor, continuously stirring the mixture in a heat collection type constant-temperature heating magnetic stirrer at room temperature to 95 ℃ for 24 hours, slowly cooling the mixture to room temperature, and filtering the mixture by using a 400-mesh filter screen to remove impurities in the solution to obtain a polyvinyl alcohol solution; (2) placing the mixture in an ultrasonic cleaner for defoaming treatment for 3 hours to obtain polyvinyl alcohol coating; (3) the polyvinyl alcohol paint for verification was coated on a metal substrate in the same manner as in step 4 of this example to obtain a coated metal; (4) the coating metal was left at room temperature and cured for 24h to make a comparative coating.
When the anticorrosive coating and the comparative coating are detected, the contact angle of the anticorrosive coating is improved by 6 times, the water absorption of the coating is reduced by 85%, the strength of the coating is improved by 7%, the impact resistance is improved by 40%, and the salt spray resistant time of the coating is improved by 11 times.
Example 10
A method for improving corrosion resistance of a polyvinyl alcohol water-based paint by heating secondary curing comprises the following steps:
step 1, dissolving a base material:
adding 3500g of deionized water into 100g of polyvinyl alcohol with alcoholysis degree of 78%, placing in a flask, adding a polytetrafluoroethylene rotor, continuously stirring for 24h in a heat collection type constant-temperature heating magnetic stirrer at room temperature to 95 ℃, slowly cooling to room temperature, and finally filtering with a 400-mesh filter screen to remove impurities in the solution to obtain pure polyvinyl alcohol solution;
step 2, mixing the filler:
respectively weighing 4g of graphene, 4g of phosphorus powder and 0.2g of SiO20.3g of SiC, and mixing uniformly to prepare a mixed filler; the size of the graphene is 900-2000 nm, the particle size of the phosphorus powder is 0.1-0.5 nm, and the particle size of the SiO powder is2The granularity of the SiC is 1-50 nm, and the granularity of the SiC is 10-20 nm; the graphene is single-layer graphene, and the thermal conductivity is 5012W/mK;
step 3, preparing the coating:
adding 0.07g of mixed filler into a polyvinyl alcohol solution, stirring for 2.5 hours, and finally placing the mixture in an ultrasonic cleaner for defoaming treatment for 2 hours to obtain a polyvinyl alcohol coating;
step 4, coating:
coating polyvinyl alcohol paint on a metal substrate, wherein the coating process of the paint comprises the following steps:
(10) pretreatment: carrying out sand blasting treatment on a metal matrix to be coated by corundum or polishing treatment by SiC abrasive paper to remove rust and impurities on the surface of the metal matrix, then scrubbing the metal matrix by adopting a mixed solution of absolute ethyl alcohol and acetone in a volume ratio of 1: 2, removing oil stains on the surface, airing, and finally putting the metal matrix into a dryer for later use;
(2) coating: taking out the metal matrix, spraying polyvinyl alcohol coating on the surface of the metal matrix by using a spray gun, wherein the coating thickness is 20-40 mu m each time, and coating for 2 times to obtain coating metal;
step 5, primary curing:
placing the coating metal at room temperature, and curing for 24 h;
and 6, secondary curing:
and (3) heating the oven to 210 ℃ in advance, keeping the temperature constant for 10min, then placing the coating metal solidified at room temperature into the oven, carrying out secondary solidification to form a film, wherein the solidification temperature is 210 ℃, the solidification time is 1h, immediately taking out the sample after solidification, placing the sample into a 5-15 ℃ cold room, and rapidly cooling.
To verify the performance of the corrosion protection coating of this example, comparative experiments were conducted as follows:
preparing a common polyvinyl alcohol coating: (1) mixing polyvinyl alcohol and deionized water according to the same mass fraction ratio as that in the step 1 of the embodiment, placing the mixture into a flask, adding a polytetrafluoroethylene rotor, continuously stirring the mixture in a heat collection type constant-temperature heating magnetic stirrer at room temperature to 95 ℃ for 24 hours, slowly cooling the mixture to room temperature, and filtering the mixture by using a 400-mesh filter screen to remove impurities in the solution to obtain a polyvinyl alcohol solution; (2) placing the mixture in an ultrasonic cleaner for defoaming for 2 hours to obtain polyvinyl alcohol coating; (3) the polyvinyl alcohol paint for verification was coated on a metal substrate in the same manner as in step 4 of this example to obtain a coated metal; (4) the coating metal was left at room temperature and cured for 24h to make a comparative coating.
When the anticorrosive coating and the comparative coating are detected, the contact angle of the anticorrosive coating is improved by 4 times, the water absorption of the coating is reduced by 70%, the strength of the coating is improved by 10%, the impact resistance is improved by 12%, and the salt spray resistant time of the coating is improved by 5 times.
Example 11
A method for improving corrosion resistance of a polyvinyl alcohol water-based paint by heating secondary curing comprises the following steps:
step 1, dissolving a base material:
adding 8500g of deionized water into 100g of polyvinyl alcohol with alcoholysis degree of 78%, placing the polyvinyl alcohol into a flask, adding a polytetrafluoroethylene rotor, continuously stirring the polyvinyl alcohol in a heat collection type constant-temperature heating magnetic stirrer at room temperature to 95 ℃ for 24 hours until the polyvinyl alcohol is fully dissolved, slowly cooling the polyvinyl alcohol to room temperature, and finally filtering the polyvinyl alcohol solution by using a 400-mesh filter screen to remove impurities in the solution to obtain pure polyvinyl alcohol solution;
step 2, mixing the filler:
respectively weighing 6g of graphene, 1g of phosphorus powder and 0.04g of SiO20.3g of SiC, and mixing uniformly to prepare a mixed filler; the size of the graphene is 900-2000 nm, the particle size of the phosphorus powder is 0.1-0.5 nm, and the particle size of the SiO powder is2The granularity of the SiC is 1-50 nm, and the granularity of the SiC is 10-20 nm; the graphene is a mixture of single-layer graphene and multi-layer graphene, and the thermal conductivity is 5010W/mK;
step 3, preparing the coating:
adding 0.03g of mixed filler into a polyvinyl alcohol solution, stirring for 2 hours, and finally placing the mixture into an ultrasonic cleaner for defoaming treatment for 3 hours to obtain a polyvinyl alcohol coating;
step 4, coating:
coating polyvinyl alcohol paint on a metal substrate, wherein the coating process of the paint comprises the following steps:
(11) pretreatment: carrying out sand blasting treatment on a metal matrix to be coated by corundum or polishing treatment by SiC abrasive paper to remove rust and impurities on the surface of the metal matrix, then scrubbing the metal matrix by adopting a mixed solution of absolute ethyl alcohol and acetone in a volume ratio of 1: 1, removing oil stains on the surface, airing, and finally putting the metal matrix into a dryer for later use;
(2) coating: taking out the metal matrix, spraying polyvinyl alcohol coating on the surface of the metal matrix by using a spray gun, wherein the coating thickness is 30-50 mu m each time, and coating for 3 times to obtain coating metal;
step 5, primary curing:
placing the coating metal at room temperature, and curing for 24 h;
and 6, secondary curing:
and (3) heating the oven to 200 ℃ in advance, keeping the temperature constant for 10min, then placing the coating metal solidified at room temperature into the oven, carrying out secondary solidification to form a film, wherein the solidification temperature is 200 ℃, the solidification time is 2h, immediately taking out the sample after solidification, placing the sample into a cold room at 5-15 ℃, and rapidly cooling.
To verify the performance of the corrosion protection coating of this example, comparative experiments were conducted as follows:
preparing a common polyvinyl alcohol coating: (1) mixing polyvinyl alcohol and deionized water according to the same mass fraction ratio as that in the step 1 of the embodiment, placing the mixture into a flask, adding a polytetrafluoroethylene rotor, continuously stirring the mixture in a heat collection type constant-temperature heating magnetic stirrer at room temperature to 95 ℃ for 24 hours, slowly cooling the mixture to room temperature, and filtering the mixture by using a 400-mesh filter screen to remove impurities in the solution to obtain a polyvinyl alcohol solution; (2) placing the mixture in an ultrasonic cleaner for defoaming treatment for 3 hours to obtain polyvinyl alcohol coating; (3) the polyvinyl alcohol paint for verification was coated on a metal substrate in the same manner as in step 4 of this example to obtain a coated metal; (4) the coating metal was left at room temperature and cured for 24h to make a comparative coating.
When the anticorrosive coating and the comparative coating are detected, the contact angle of the anticorrosive coating is improved by 6 times, the water absorption of the coating is reduced by 70%, the strength of the coating is improved by 40%, the impact resistance is improved by 35%, and the salt spray resistant time of the coating is improved by 10 times.
Example 12
A method for improving corrosion resistance of a polyvinyl alcohol water-based paint by heating secondary curing comprises the following steps:
step 1, dissolving a base material:
adding 4000g of deionized water into 100g of polyvinyl alcohol with alcoholysis degree of 78%, placing the polyvinyl alcohol in a flask, adding a polytetrafluoroethylene rotor, continuously stirring the polyvinyl alcohol in a heat collection type constant-temperature heating magnetic stirrer at room temperature to 95 ℃ for 24 hours until the polyvinyl alcohol is fully dissolved, slowly cooling the polyvinyl alcohol to room temperature, and finally filtering the polyvinyl alcohol solution by using a 400-mesh filter screen to remove impurities in the solution to obtain pure polyvinyl alcohol solution;
step 2, mixing the filler:
respectively weighing 5.3g of graphene, 3.2g of phosphorus powder and 0.25g of SiO20.23g of SiC, and mixing uniformly to prepare a mixed filler; the size of the graphene is 900-2000 nm, the particle size of the phosphorus powder is 0.1-0.5 nm, and the particle size of the SiO powder is2The granularity of the SiC is 1-50 nm, and the granularity of the SiC is 10-20 nm; the graphene is multilayer graphene, and the thermal conductivity is 5010W/mK;
step 3, preparing the coating:
adding 0.43g of mixed filler into a polyvinyl alcohol solution, stirring for 2 hours, and finally placing the mixture into an ultrasonic cleaner for defoaming treatment for 2 hours to obtain a polyvinyl alcohol coating;
step 4, coating:
coating polyvinyl alcohol paint on a metal substrate, wherein the coating process of the paint comprises the following steps:
(12) pretreatment: carrying out sand blasting treatment on a metal matrix to be coated by corundum or polishing treatment by SiC abrasive paper to remove rust and impurities on the surface of the metal matrix, then scrubbing the metal matrix by adopting a mixed solution of absolute ethyl alcohol and acetone in a volume ratio of 1: 1, removing oil stains on the surface, airing, and finally putting the metal matrix into a dryer for later use;
(2) coating: taking out the metal matrix, spraying polyvinyl alcohol coating on the surface of the metal matrix by using a spray gun, wherein the coating thickness is 50-70 mu m each time, and coating for 2 times to obtain coating metal;
step 5, primary curing:
placing the coating metal at room temperature, and curing for 24 h;
and 6, secondary curing:
and (3) heating the oven to 220 ℃ in advance, keeping the temperature constant for 10min, then placing the coating metal solidified at room temperature into the oven, carrying out secondary solidification to form a film, wherein the solidification temperature is 220 ℃, the solidification time is 2h, immediately taking out the sample after solidification, placing the sample into a 5-15 ℃ cold room, and rapidly cooling the sample.
To verify the performance of the corrosion protection coating of this example, comparative experiments were conducted as follows:
preparing a common polyvinyl alcohol coating: (1) mixing polyvinyl alcohol and deionized water according to the same mass fraction ratio as that in the step 1 of the embodiment, placing the mixture into a flask, adding a polytetrafluoroethylene rotor, continuously stirring the mixture in a heat collection type constant-temperature heating magnetic stirrer at room temperature to 95 ℃ for 24 hours, slowly cooling the mixture to room temperature, and filtering the mixture by using a 400-mesh filter screen to remove impurities in the solution to obtain a polyvinyl alcohol solution; (2) placing the mixture in an ultrasonic cleaner for defoaming for 2 hours to obtain polyvinyl alcohol coating; (3) the polyvinyl alcohol paint for verification was coated on a metal substrate in the same manner as in step 4 of this example to obtain a coated metal; (4) the coating metal was left at room temperature and cured for 24h to make a comparative coating.
When the anticorrosive coating and the comparative coating are detected, the contact angle of the anticorrosive coating is improved by 7 times, the water absorption of the coating is reduced by 72%, the strength of the coating is improved by 38%, the impact resistance is improved by 44%, and the salt spray resistant time of the coating is improved by 9 times.

Claims (7)

1. A method for improving corrosion resistance of a polyvinyl alcohol water-based paint by heating secondary curing is characterized by comprising the following steps:
step 1, dissolving a base material:
according to the weight percentage of polyvinyl alcohol: 100 parts of deionized water: (1-20000), mixing polyvinyl alcohol and deionized water, placing the mixture in a container, adding a polytetrafluoroethylene rotor, continuously stirring the mixture in a heat collection type constant-temperature heating magnetic stirrer at room temperature to 95 ℃ until the polyvinyl alcohol is fully dissolved, slowly cooling the mixture to room temperature, and finally filtering the mixture by using a filter screen to remove impurities in the solution to obtain pure polyvinyl alcohol solution;
step 2, mixing the filler:
according to the graphene: phosphorus powder: SiO 22：SiC＝(3～7): (1-5): (0.01-0.5): (0.1-5) weighing graphene, phosphorus powder and SiO in percentage by mass2And SiC, and mixing uniformly to prepare a mixed filler; the graphene is 900-2000 nm in size, the phosphorus powder is 0.1-0.5 nm in particle size, and SiO is added2The granularity of the SiC is 1-50 nm, and the granularity of the SiC is 10-20 nm;
step 3, preparing the coating:
according to the weight percentage of polyvinyl alcohol: mixed filler 100: (0.01-1), adding a mixed filler into the polyvinyl alcohol solution, uniformly stirring, and finally placing the solution in an ultrasonic cleaner for defoaming treatment for 1-3 hours to obtain a polyvinyl alcohol coating;
step 4, coating:
coating polyvinyl alcohol paint on a metal substrate, wherein the coating process of the paint comprises the following steps:
(1) pretreatment: carrying out sand blasting treatment on a metal matrix to be coated by corundum or polishing treatment by SiC abrasive paper to remove rust and impurities on the surface of the metal matrix, then scrubbing the metal matrix by adopting a mixed solution of absolute ethyl alcohol and acetone to remove oil stains on the surface, airing, and finally placing the metal matrix into a dryer for storage or direct use;
(2) coating: taking out the metal substrate, coating polyvinyl alcohol paint on the surface of the metal substrate, wherein the coating thickness is 10-150 mu m each time, coating for 1-5 times, and after the surface of the coating coated on the previous time is dried for 10 hours each time, performing the next coating procedure to ensure that the coating directions of two adjacent times are mutually vertical, so that bubbles generated in the coating process are avoided, and the total thickness of the coating is controlled by the coating times to obtain coating metal;
step 5, primary curing:
placing the coating metal at room temperature, and curing for 24-48 h;
and 6, secondary curing:
heating an oven to 170-230 ℃ in advance, keeping the temperature constant for 10min, then placing the coating metal cured at room temperature into the oven, and performing secondary curing to form a film, wherein the curing temperature is 170-230 ℃, and the curing time is 1-5 h;
and (4) immediately taking out the sample after solidification, placing the sample in a cold room at 5-15 ℃, and rapidly cooling.
2. The method for improving the corrosion resistance of the polyvinyl alcohol water-based paint by temperature-rising secondary curing according to claim 1, wherein in the step 1, the alcoholysis degree of the polyvinyl alcohol is 78-98%.
3. The method for improving the corrosion resistance of the polyvinyl alcohol water-based paint by heating and secondary curing according to claim 1, wherein in the step 1, the mass fraction ratio of the polyvinyl alcohol to the deionized water is preferably polyvinyl alcohol: 100 parts of deionized water: (1-10000).
4. The method for improving the corrosion resistance of the polyvinyl alcohol water-based paint by temperature-rising secondary curing according to claim 1, wherein in the step 2, the thermal conductivity of the graphene is (4840 +/-440) - (5300 +/-480) W/mK, and the graphene is one or a mixture of single-layer graphene and multi-layer graphene.
5. The method for improving the corrosion resistance of the polyvinyl alcohol water-based paint by temperature-rising secondary curing according to claim 1, wherein in the step 3, the stirring time is 2-3 h.
6. The method for improving the corrosion resistance of the polyvinyl alcohol water-based paint by temperature-rising secondary curing according to claim 1, wherein in the step 4(1), the volume ratio of the absolute ethyl alcohol to the acetone is 1: 1 or 1: 2.
7. The method for improving the corrosion resistance of the polyvinyl alcohol water-based paint by temperature-rising secondary curing according to claim 1, wherein in the step 4(2), the coating is brushed, sprayed, dripped or dipped.
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