CN108192403B

CN108192403B - Solvent type zinc-aluminum coating

Info

Publication number: CN108192403B
Application number: CN201810064748.6A
Authority: CN
Inventors: 张志恒
Original assignee: Winstar Chemicals Shanghai Co Ltd
Current assignee: Winstar Chemicals Shanghai Co Ltd
Priority date: 2018-01-23
Filing date: 2018-01-23
Publication date: 2020-04-17
Anticipated expiration: 2038-01-23
Also published as: CN108192403A

Abstract

The invention relates to the field of metal surface protection, in particular to a solvent type zinc-aluminum coating. A solvent type zinc-aluminum coating is prepared from a component A and a component B according to a mass ratio of 4: 1-5: 1, mixing; the component A comprises the following components in parts by weight: 75-90 parts of zinc-aluminum alloy powder, 15-18 parts of organic solvent, 3-12 parts of filler, 0.2-0.7 part of coupling agent and 0.3-0.9 part of anti-settling agent; the component B is tetraethoxysilane hydrolysate; the anti-settling auxiliary agent is MoS₂And isocyanate-terminated hyperbranched polyurethane, said MoS₂And the isocyanate group-terminated hyperbranched polyurethane in a mass ratio of 5-9: 1.

Description

Solvent type zinc-aluminum coating

Technical Field

The invention relates to the field of metal protection, in particular to a solvent type zinc-aluminum coating.

Background

Metal corrosion widely exists in nature, which not only causes resource waste, but also sometimes even causes accidents, and brings immeasurable loss to the life and property safety of people. On a world scale, all materials lose about 1% of weight per year due to corrosion, economic loss caused by corrosion accounts for about 4% of the total national economic amount, the loss is more serious in tropical and marine environments, the loss caused by marine corrosion only in China currently exceeds 3% of GDP, and the corrosion-resistant roads are far in burden. The industries such as ocean engineering, ship manufacturing, green ocean wind energy and the like are rapidly developed, the industrial anticorrosive paint and coating field enters the gold period of high-speed growth, and the market scale of the industrial anticorrosive paint is second to the architectural paint in various paint varieties. In recent years, China has huge coating requirements in infrastructure construction, town integrated construction and new rural construction, Olympic games, sub-Athletic games, Shanghai world Expo and the biggest Disneyland all over the world, and the like, provides a new opportunity for the rapid development of coating industry and industrial anticorrosive coatings under new international situation and national policy, vigorously develops novel anticorrosive coatings, and has wide prospects and practical significance.

Based on this background, the present invention provides a solvent-based zinc-aluminum coating material having excellent properties, which can be dried quickly at a relatively low temperature and humidity, and has good adhesion, good flexibility, excellent corrosion resistance, and excellent corrosion resistance even when a relatively thin coating is applied.

The solvent-type zinc-aluminum coating can be applied to various fields, including: emerging ocean engineering: offshore facilities, coastal and bay structures, offshore oil platforms; modern transportation; energy industry: hydraulic equipment, petroleum refining equipment, petroleum storage equipment, power transmission and transformation equipment, nuclear power, solar power generation equipment and wind power generation equipment; large industrial enterprises; municipal facilities, and the like.

Disclosure of Invention

The invention provides a solvent-type zinc-aluminum coating, which is prepared from a component A and a component B in a mass ratio of 4: 1-5: 1, mixing; the component A comprises the following components in parts by weight: 75-90 parts of zinc-aluminum alloy powder, 15-18 parts of organic solvent, 3-12 parts of filler, 0.2-0.7 part of coupling agent and 0.3-0.9 part of anti-settling agent; the component B is tetraethoxysilane hydrolysate; the anti-settling auxiliary agent is MoS₂And isocyanate-terminated hyperbranched polyurethane, said MoS₂And the isocyanate group-terminated hyperbranched polyurethane in a mass ratio of 5-9: 1.

as a preferable technical scheme of the invention, the organic solvent is selected from ethanol, n-butanol, isopropanol, tert-butanol, butanone, cyclohexanone, butyl acetate, ethylene glycol ethyl ether acetate, ethylene glycol butyl ether, butanediol methyl ether, methyl isobutyl ketone, isobutyl acetate, ethyl acetate, octyl acetate, methyl ethyl ketone, methyl isobutyl ketone, methyl hexyl ketone, 120^#Solvent oil, 200^#Mineral spirit, D30^#Mineral spirit, D40^#Mineral spirit, D60^#Mineral spirit, D65^#Mineral spirit, D80^#Mineral spirit, D90^#Solvent oil, D100^#Mineral spirit, D110^#Mineral spirit, D130^#Solvent oil, D160^#Any one or more of mineral spirits.

As a preferable technical scheme of the invention, the filler is selected from modified graphene, ferrotitanium powder, hydrotalcite, bentonite, wollastonite powder, zinc oxide and La₂O₃、Ce₂O₃、CeO₂、Ce₉O₁₆、Ce₇O₁₂、Ce₆O₁₁、Ce₁₀O₈、Ce₁₁O₂₀、Pr₆O₁₁、PrO_1.65、PrO_1.714、PrO_1.800、Nd₂O₃、Tb₂O₃、Tb₄O₅、Tb₄O₇、Ho₂O₃、Sm₂O₃、Tm₂O₃、Yb₂O₃、Y₂O₃、MnO₂、WO₃、WO_2.90、WO_2.72、WO₂、MoO₃Any one or more of.

According to a preferable technical scheme of the invention, the filler is a mixture of modified graphene, talcum powder, zinc oxide and hydrotalcite, and the mass ratio of the modified graphene to the talcum powder to the zinc oxide to the hydrotalcite is 0.2-0.5: 1-3: 3-4: 0.3 to 0.7.

As a preferable technical scheme, the modified graphene is furan resin modified graphene.

As a preferable technical scheme of the invention, the coupling agent is selected from any one or more of silane coupling agent, titanate coupling agent, zirconate coupling agent and aluminate coupling agent.

In a preferred embodiment of the present invention, the coupling agent is selected from one or more of gamma-aminopropyltriethoxysilane, N-phenylaminomethyltriethoxysilane, (3-trimethoxysilylpropyl) diethylethylenediamine, anilinomethyltrimethoxysilane, gamma-glycidoxypropyltrimethoxysilane, gamma-glycidoxypropyltriethoxysilane, β - (3, 4-epoxycyclohexyl) ethyltrimethoxysilane, 3- (methacryloyloxy) propyltrimethoxysilane, gamma-mercaptopropyltrimethoxysilane, gamma-mercaptopropylmethyldimethoxysilane, bis- (gamma-triethoxysilyl) -tetrasulfide, 3- (methacryloyloxy) propyltrimethoxysilane, vinyltris (2-methoxyethoxy) silane, vinyltrimethoxysilane, isopropyltris (dioctylphosphato) titanate, isopropyldioleato (dioctylphosphato) titanate, isopropyltriisocyanate isopropyl titanate, bis (dioctyloxypyrophosphate) ethylenetitanate, tetraisopropylbis (dioctylphosphato) titanate, tetra (stearyloxypropyl) titanate, and di-or more of these.

In a preferred technical scheme of the invention, the solvent-based zinc-aluminum coating further comprises other auxiliary agents, wherein the auxiliary agents are selected from one or more of pigments, wetting dispersants, toughening agents, thickening agents, leveling auxiliary agents and solid lubricants.

The second aspect of the invention provides a preparation method of the solvent-type zinc-aluminum coating, which is characterized by at least comprising the following steps:

a. adding zinc-aluminum alloy powder, an organic solvent, a filler, a coupling agent and an anti-settling agent into a container according to the parts by weight, stirring for 0.5-1 h, and dispersing and mixing uniformly to obtain a component A;

b. and c, mixing the component A and the component B obtained in the step a according to a ratio, and stirring for 0.5-1 h to obtain the solvent type zinc-aluminum coating.

The third aspect of the invention provides the application of the solvent-type zinc-aluminum coating in the field of metal surface protection.

The above-described and other features, aspects, and advantages of the present application will become more apparent with reference to the following detailed description.

The solvent type zinc-aluminum coating disclosed by the invention has very excellent performance, can be quickly dried at a lower temperature and humidity, and is good in coating adhesion, good in flexibility and excellent in corrosion resistance.

Detailed Description

The disclosure may be understood more readily by reference to the following detailed description of preferred embodiments of the invention and the examples included therein. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In case of conflict, the present specification, including definitions, will control.

The term "prepared from …" as used herein is synonymous with "comprising". The terms "comprises," "comprising," "includes," "including," "has," "having," "contains," "containing," or any other variation thereof, as used herein, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

The conjunction "consisting of …" excludes any unspecified elements, steps or components. If used in a claim, the phrase is intended to claim as closed, meaning that it does not contain materials other than those described, except for the conventional impurities associated therewith. When the phrase "consisting of …" appears in a clause of the subject matter of the claims rather than immediately after the subject matter, it defines only the elements described in the clause; other elements are not excluded from the claims as a whole.

When an amount, concentration, or other value or parameter is expressed as a range, preferred range, or as a range of upper preferable values and lower preferable values, this is to be understood as specifically disclosing all ranges formed from any pair of any upper range limit or preferred value and any lower range limit or preferred value, regardless of whether ranges are separately disclosed. For example, when a range of "1 to 5" is disclosed, the described range should be interpreted to include the ranges "1 to 4", "1 to 3", "1 to 2 and 4 to 5", "1 to 3 and 5", and the like. When a range of values is described herein, unless otherwise stated, the range is intended to include the endpoints thereof and all integers and fractions within the range.

The singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. "optional" or "any" means that the subsequently described event or events may or may not occur, and that the description includes instances where the event occurs and instances where it does not.

Approximating language, as used herein throughout the specification and claims, is intended to modify a quantity, such that the invention is not limited to the specific quantity, but includes portions that are literally received for modification without substantial change in the basic function to which the invention is related. Accordingly, the use of "about" to modify a numerical value means that the invention is not limited to the precise value. In some instances, the approximating language may correspond to the precision of an instrument for measuring the value. In the present description and claims, range limitations may be combined and/or interchanged, including all sub-ranges contained therein if not otherwise stated.

In addition, the indefinite articles "a" and "an" preceding an element or component of the invention are not intended to limit the number requirement (i.e., the number of occurrences) of the element or component. Thus, "a" or "an" should be read to include one or at least one, and the singular form of an element or component also includes the plural unless the stated number clearly indicates that the singular form is intended.

The invention provides a solvent-type zinc-aluminum coating, which is prepared from a component A and a component B in a mass ratio of 4: 1-5: 1, mixing; the component A comprises the following components in parts by weight: 75-90 parts of zinc-aluminum alloy powder, 15-18 parts of organic solvent, 3-12 parts of filler, 0.2-0.7 part of coupling agent and 0.3-0.9 part of anti-settling agent; the component B is tetraethoxysilane hydrolysate.

Zinc-aluminum alloy powder

The potential of zinc is far negative to that of carbon steel, when the coating is damaged carelessly or after long-term use, water, oxygen and chloride ions permeate to the interface between the coating and the steel, the zinc in the coating becomes a sacrificial anode, and the steel can be protected from corrosion for a long time. And zinc reacts with water, oxygen, chloride ions and carbon dioxide and forms corrosion products such as insoluble salts, e.g. 2ZnCO₃·Zn(OH)₂And Zn₅(OH)₈Cl₂And the volume of the metal zinc oxide particles is larger than that of consumed metal zinc, so that the pores of the coating are favorably blocked, and the surface of the coating is more compact. In addition, during the corrosion process, a compact alumina film is easily generated on the surface of the aluminum, the oxidation-reduction reaction of the cathode can be greatly inhibited, the reduction of the cathode current causes the reduction of the anode current, and thus the dissolution of zinc and the formation of white rust are inhibited. When the scaly zinc-aluminum powder is mixed into a coating to be coated into a film, the metal scales are parallel to the surface of the base material and are arranged in multiple layers and mutually covered to form a layer-by-layer barrier, so that a corrosive medium is prolonged to reach the surface of the base carbon steel, the permeability of the coating is obviously reduced, and corrosive factors such as water, oxygen and the like in the environment are better shielded. In the solvent-type zinc-aluminum coating of the invention, the zinc-aluminum alloy powder endows the coating with electrochemical protectionThe metal protective film has double effects of ' and ' mechanical barrier ', and has more excellent metal protective performance.

The zinc-aluminum powder mixture is used in the traditional chromium-free zinc-aluminum coating, but the density difference of Zn and Al is large, and weight segregation is easily caused, so that zinc powder and aluminum powder in a coating liquid with high aluminum powder content are not uniformly dispersed, a local aluminum powder enrichment phenomenon inevitably exists, and local remarkable zinc deficiency is caused. The zinc-aluminum alloy powder can avoid the condition that the zinc powder and the aluminum powder are not uniformly dispersed when the zinc powder and the aluminum powder are used, and has the cathode protection capability of the zinc powder and the high corrosion resistance of the aluminum powder.

As a preferable technical scheme of the invention, the zinc-aluminum alloy powder is flaky, the particle size is 500-800 meshes, and the aluminum content in the zinc-aluminum alloy powder is 10-30 wt%.

The zinc-aluminum alloy powder of the present invention is available from Scott chemical Co., Ltd.

As a preferred technical solution of the present invention, the organic solvent is selected from any one or more of alcohols, ethers, ketones, esters, and alkanes.

The alcohol may be ethanol, n-butanol, isopropanol, tert-butanol, etc.;

the ether may be exemplified by ethylene glycol butyl ether, butanediol methyl ether, etc.;

the ketones include, for example, methyl ethyl ketone, cyclohexanone, methyl isobutyl ketone, methyl ethyl ketone, methyl isobutyl ketone, and methyl hexyl ketone;

the ester may be exemplified by butyl acetate, ethylene glycol monoethyl ether acetate, isobutyl acetate, ethyl acetate, octyl acetate, etc.;

the alkane comprises branched alkane, cycloalkane and the like, and the alkane contains 6-18 carbon atoms.

The alkane may be commercially available solvent oil, such as 120^#Solvent oil, 200^#Mineral spirit, D30^#Mineral spirit, D40^#Mineral spirit, D60^#Mineral spirit, D65^#Mineral spirit, D80^#Mineral spirit, D90^#Solvent oil, D100^#Mineral spirit, D110^#Mineral spirit, D130^#Solvent oil, D160^#Solvent oil, etc.

The filler is mainly used for improving the overall corrosion resistance of the coating by improving the conductivity of the coating, enhancing the cathode protection, reducing the electrochemical activity of zinc powder in the coating, delaying the corrosion speed or changing the shielding protection effect of the coating. The addition of the filler can also reduce the addition of the zinc-aluminum powder and the production cost of the coating.

The filler of the present invention is not limited to other materials, and there may be mentioned: modified graphene, iron titanium powder, talcum powder, wollastonite powder, zinc oxide, barium sulfate, zirconium silicide, zirconium carbide, zirconia fiber, aluminum silicate fiber, potassium titanate whisker, aluminum borate whisker, mullite whisker, silicon carbide whisker, bentonite, high titanium ash, mica powder, kaolin, calcium carbonate, quartz powder, feldspar powder, calcined china clay, zeolite, molecular sieve, hydrotalcite, barite powder, montmorillonite, fumed silica, rare earth metal oxide and the like.

The rare earth metal oxide is not limited to other elements, and may be an oxide of a metal such as La, Ce, Pr, Nd, Pm, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, or the like.

The rare earth goldOxides of the genus may be mentioned by La₂O₃、Ce₂O₃、CeO₂、Ce₉O₁₆、Ce₇O₁₂、Ce₆O₁₁、Ce₁₀O₈、Ce₁₁O₂₀、Pr₆O₁₁、PrO_1.65、PrO_1.714、PrO_1.800、Nd₂O₃、Tb₂O₃、Tb₄O₅、Tb₄O₇、Ho₂O₃、Sm₂O₃、Tm₂O₃、Yb₂O₃、Y₂O₃、MnO₂、WO₃、WO_2.90、WO_2.72、WO₂、MoO₃And the like.

As a preferred technical scheme of the invention, the filler is selected from modified graphene, iron titanium powder, talcum powder, wollastonite powder, zinc oxide, barium sulfate, zirconium silicide, zirconium carbide, zirconium oxide fiber, aluminum silicate fiber, potassium titanate whisker, aluminum borate whisker, mullite whisker, silicon carbide whisker, bentonite, high titanium ash, mica powder, kaolin, calcium carbonate, quartz powder, feldspar powder, calcined china clay, zeolite, molecular sieve, hydrotalcite, barite powder, montmorillonite, fumed silica, La and La₂O₃、Ce₂O₃、CeO₂、Ce₉O₁₆、Ce₇O₁₂、Ce₆O₁₁、Ce₁₀O₈、Ce₁₁O₂₀、Pr₆O₁₁、PrO_1.65、PrO_1.714、PrO_1.800、Nd₂O₃、Tb₂O₃、Tb₄O₅、Tb₄O₇、Ho₂O₃、Sm₂O₃、Tm₂O₃、Yb₂O₃、Y₂O₃、MnO₂、WO₃、WO_2.90、WO_2.72、WO₂、MoO₃Any one or more of.

As a preferred technical solution of the present invention,the filler is selected from modified graphene, ferrotitanium powder, hydrotalcite, bentonite, wollastonite powder, zinc oxide and La₂O₃、Ce₂O₃、CeO₂、Ce₉O₁₆、Ce₇O₁₂、Ce₆O₁₁、Ce₁₀O₈、Ce₁₁O₂₀、Pr₆O₁₁、PrO_1.65、PrO_1.714、PrO_1.800、Nd₂O₃、Tb₂O₃、Tb₄O₅、Tb₄O₇、Ho₂O₃、Sm₂O₃、Tm₂O₃、Yb₂O₃、Y₂O₃、MnO₂、WO₃、WO_2.90、WO_2.72、WO₂、MoO₃Any one or more of.

According to a preferable technical scheme of the invention, the filler is a mixture of modified graphene, talcum powder, zinc oxide and hydrotalcite, and the mass ratio of the modified graphene to the talcum powder to the zinc oxide to the hydrotalcite is 0.3: 2: 3: 0.5.

As a preferred technical scheme of the present invention, the preparation method of the modified graphene at least comprises the following steps:

a. adding dissolved K into lithotripsy ink₂S₂O₈And P₂O₅In 18mol/L sulfuric acid solution at 80 ℃, graphite powder and K₂S₂O₈、P₂O₅And sulfuric acid in a mass ratio of 2: 1: 1: 5, stirring, naturally cooling to room temperature, diluting with deionized water, filtering, washing with water to neutrality, and airing the product in the air; will be at the topAdding the product into 18mol/L sulfuric acid in an ice bath, and gradually adding KMnO in the stirring process₄Graphite powder, sulfuric acid and KMnO₄The mass ratio of (1): 36: 3, controlling the reaction temperature within 15 ℃; then transferring the mixture into a water bath at 35 ℃, gradually adding deionized water, wherein the mass of the deionized water is 45 times that of the graphite powder, and stirring for reaction for 2 hours; and then adding deionized water and 30 wt% of hydrogen peroxide to terminate the reaction, wherein the mass ratio of the graphite powder to the deionized water to the 30 wt% of hydrogen peroxide is 1: 140: 3, filtering, washing with 3.7 wt% hydrochloric acid to remove metal ions, centrifugally separating, and drying at 50 ℃ for 12 hours to obtain a product a;

b. and (3) dissolving the product a in furfuryl alcohol, wherein the mass ratio of the product a to the furfuryl alcohol is 1: 75, performing ultrasonic treatment for 3-8 hours; then adding acetic acid, wherein the mass ratio of the acetic acid to the furfuryl alcohol is 0.4: 1, stirring for 0.5-1.5 h; adding the furoyl, wherein the mass ratio of the furoyl to the furfuryl alcohol is 1: 0.8, reacting for 4 hours at the temperature of 100-110 ℃; stopping heating, naturally cooling the mixture, adding ethylenediamine to adjust the pH value to 7, performing vacuum dehydration to reduce the water content of the product to below 2%, and cooling to 30 ℃ to obtain the modified graphene.

Graphite powder, CAS: 7782-42-5, from Chemicals, Inc., national drug group.

Furfuryl alcohol, CAS: 98-00-0, available from national pharmaceutical group chemical agents, Inc.

Furoyl, CAS: 492-94-4, available from Alfa Aesar (Alfa Aesar).

Talcum powder

Talc powder is a hydrous magnesium silicate mineral with a composition of 3 MgO.4SiO₂·H₂And O. In the lattice structure of superfine talcum powder, silicon-oxygen tetrahedron is connected into layered structure, and the layers are easy to crack owing to weak hydrogen bond attraction, and have relatively high length-diameter ratio. At present, the superfine talcum powder is widely applied to the industries of coating, paper making, plastics, cosmetics and the like.

The talcum powder can endow the coating with excellent brushing property, leveling property and gloss retention, the coating containing the talcum powder has better impact resistance and flexibility and higher hardness, and meanwhile, the talcum powder can also effectively improve the corrosion resistance of the coating. The sheet structure of the talcum powder can effectively improve the leveling property of the coating, fill gaps among the zinc-aluminum alloy powder, reduce coating defects, improve the shielding property of the coating, and effectively prolong the diffusion path of a corrosive medium, thereby improving the corrosion resistance of the coating. Meanwhile, the talcum powder can endow the coating with higher impact resistance and fracture toughness due to higher length-diameter ratio.

The talcum powder of the invention is 1250-mesh superfine talcum powder and is purchased from Shanghai Yangjiang chemical industry Co.

Zinc oxide

The zinc oxide has small particle size, large specific surface area and strong adhesive force and covering power, and the effect of the coating can be greatly improved by adding the zinc oxide into the coating; the zinc oxide has small specific gravity, and is not easy to form precipitates in use or final products; in addition, the zinc oxide also has a certain ultraviolet shielding effect and can play an anti-aging role in the coating. Researches prove that the corrosion resistance of the coating obtained by the zinc-aluminum coating can be improved by adding a proper amount of zinc oxide. The action mechanism of improving the corrosion resistance of the zinc oxide is as follows: on the one hand, zinc with p-type semiconductor property and zinc oxide as n-type semiconductor are contacted to form a p-n junction, which allows electrons to flow through, can well control corrosion electrochemical reaction and provides better cathode protection for the matrix; on the other hand, the zinc oxide particles can fill the pores of the coating and improve the shielding performance.

The zinc oxide of the invention is purchased from Shanghai Yangjiang chemical Co., Ltd, and the model is coating pigment grade.

Hydrotalcite

Hydrotalcite is a layered inorganic material with wide application prospect, and the ideal chemical composition is Mg₆Al₂(OH)₁₆CO₃·4H₂O, CAS: 11097-59-9, the structure is similar to brucite Mg (OH)₂. Hydrotalcite based hexagonal system, from Mg²⁺、Al³⁺、OH^-The unit layer plates are positively charged, so that exchangeable anions CO exist between layers₃ ^2-So as to balance the charge and make the whole crystal be electrically neutral; a certain number of water molecules are also present between the laminates becauseThe binding force is small, and the hydrotalcite can be removed at a proper temperature without damaging the structure of the hydrotalcite. Different cations on the laminate and different anions between the layers form different kinds of hydrotalcite. Such a structure of hydrotalcite determines that it mainly has basicity, interlayer anion exchange properties and thermal stability.

The hydrotalcite of the invention is purchased from Jingjiang city Kanggao Special plastics science and technology Limited company, and the model is FM 300.

Coupling agent

The coating obtained by using the solvent type zinc-aluminum coating is brittle and poor in flexibility, a coupling agent is generally required to be added for improving the workability, the flexibility of an alkyl side chain of ethyl orthosilicate serving as a film-forming agent can be enhanced by adding the coupling agent, a relatively complete coating can be obtained, and the corrosion resistance of the zinc-aluminum coating is further enhanced. Coupling agents, also known as adhesion promoters, are compounds that have in the molecule groups that can interact physically or chemically with inorganic materials, as well as groups that can interact physically or chemically with polymers. Because it can act with inorganic substance and polymer at the same time, it can build up "molecular bridge" on the interface of inorganic material and high-molecular synthetic material to make them combine tightly to attain the goal of strengthening, so that it is called coupling agent.

The coupling agent of the present invention is not limited to other coupling agents, and examples thereof include silane coupling agents, titanate coupling agents, zirconate coupling agents, aluminate coupling agents, rare earth salt coupling agents, and the like.

Examples of the silane coupling agent include an aminosilane coupling agent, an epoxy silane coupling agent, a mercapto silane coupling agent, and a vinyl silane coupling agent.

As the aminosilane coupling agent, gamma-aminopropyltriethoxysilane, N-phenylaminomethyltriethoxysilane, (3-trimethoxysilylpropyl) diethylethylenediamine, anilinomethyltrimethoxysilane and the like can be mentioned.

Examples of the epoxysilane coupling agent include gamma-glycidoxypropyltrimethoxysilane, gamma-glycidoxypropyltriethoxysilane, β - (3, 4-epoxycyclohexyl) ethyltrimethoxysilane, 3- (methacryloyloxy) propyltrimethoxysilane and the like.

Examples of the mercaptosilane coupling agent include gamma-mercaptopropyltrimethoxysilane, gamma-mercaptopropylmethyldimethoxysilane, and bis- (gamma-triethoxysilylpropyl) -tetrasulfide.

Examples of the vinyl silane coupling agent include 3- (methacryloyloxy) propyltrimethoxysilane, vinyltris (2-methoxyethoxy) silane, and vinyltrimethoxysilane.

The titanate coupling agent is not limited to others, and isopropyl tris (dioctylphosphonoate) titanate, isopropyl dioleate acyloxy (dioctylphosphonoate) titanate, isopropyl triisostearate titanate, bis (dioctyloxypyrophosphate) ethylene titanate, tetraisopropyl bis (dioctylphosphonoate) titanate and the like can be mentioned.

The zirconate coupling agent refers to tetra-n-propyl zirconate, CAS: 23519-77-9.

The aluminate coupling agent is not particularly limited, and may include SG-AI821 (distearoyloxyisopropyl aluminate), DL-411AF, DL-411D, DL-411DF, and anti-settling aluminate ASA.

The rare earth salt coupling agent comprises a chemical salt of a metal element of groups IIIB-VIIB other than chromium.

The above-mentioned chemical salts of metal elements other than chromium in groups IIIB to VIIB are not particularly limited, and there may be mentioned chemical salts of metals such as Sc, Ti, V, Mn, Y, Zr, Nb, Mo, Tc, Lu, Hf, Ta, W, Re, La, Ce and Pr.

As a preferable technical scheme of the invention, the coupling agent is selected from any one or more of silane coupling agent, titanate coupling agent, zirconate coupling agent, aluminate coupling agent and rare earth salt coupling agent.

As a preferred technical scheme of the invention, the coupling agent is selected from one or more of gamma-aminopropyl triethoxysilane, N-phenylaminomethyl triethoxysilane, (3-trimethoxysilylpropyl) diethyl ethylenediamine and aniline methyl trimethoxysilane.

Anti-settling auxiliary agent

In order to prevent the solvent-type zinc-aluminum coating from settling during construction and improve the storage property, a dustproof assistant is required to be added. The anti-settling auxiliary of the present invention may be exemplified by: organobentonite, isocyanate-terminated hyperbranched polyurethane, organoclay, fumed silica and MoS₂Graphite powder and talcum powder.

As a preferred technical scheme of the invention, the anti-settling auxiliary agent is MoS₂And isocyanate-terminated hyperbranched polyurethane, said MoS₂And the isocyanate group-terminated hyperbranched polyurethane in a mass ratio of 5-9: 1.

₂MoS

MoS₂molybdenum disulfide, english name molybdenum disulfide, CAS: 1317-33-5, main component of molybdenite. Black solid powder with metallic luster. The chemical formula MoS2, the melting point 1185 ℃, the density of 4.80g/cm3(14 ℃), and the Mohs hardness of 1.0-1.5. Molybdenum disulfide is an important solid lubricant, and is particularly suitable for high temperature and high pressure. It is also diamagnetic and can be used as a linear photoconductor and a semiconductor exhibiting P-type or N-type conductivity, having rectifying and transducing functions. Molybdenum disulfide is also useful as a catalyst for the dehydrogenation of complex hydrocarbons. It is also known as "high-grade solid lubricating oil king".

The molybdenum disulfide is solid powder prepared by changing the molecular structure of natural molybdenum concentrate powder after chemical purification. The product has a silver gray color, metallic luster, greasy touch and water insolubility. The product has the advantages of good dispersibility and non-caking property, can be added into various grease to form a colloidal state without caking, and can increase the lubricating property and extreme pressure property of the grease. The device is also suitable for mechanical working states with high temperature, high pressure, high rotating speed and high load, and the service life of the device is prolonged. The molybdenum disulfide is used for friction materials and has the main functions of friction reduction at low temperature, friction increase at high temperature, small loss on ignition and easy volatilization in the friction materials. The pH value of the molybdenum disulfide is 7-8, and the molybdenum disulfide is slightly alkaline. It is covered on the surface of friction material, and can protect other materials, prevent them from being oxidized, and can make other materials not be easily fallen off, and its adhesion force is raised.

As a preferred technical solution of the present invention, the preparation method of the isocyanate group-terminated hyperbranched polyurethane at least comprises the following steps:

a. dissolving isophorone diisocyanate and glycerol in a dimethyl sulfoxide solvent respectively to obtain an isophorone diisocyanate solution and a glycerol solution;

b. adding isophorone diisocyanate solution into glycerol solution at 80 ℃ under the protection of nitrogen with stirring, wherein the molar ratio of isocyanate groups to hydroxyl groups is 2: 1; after the isophorone diisocyanate solution is added, the reaction system is subjected to heat preservation reaction for 12 hours; then adding a protective agent caprolactam into the reaction system, and continuously reacting for 10 hours at 100 ℃;

c. after the reaction is finished, the solvent is distilled out under reduced pressure, the obtained substance is dissolved in tetrahydrofuran, and after the solution is settled and filtered in methanol, the solution is dried for 15 hours under vacuum at 100 ℃ to obtain the isocyanate group terminated hyperbranched polyurethane.

As a preferable technical scheme of the invention, the preparation method of the tetraethoxysilane hydrolysate at least comprises the following steps:

adding distilled water into a mixed solution of n-butyl alcohol, propylene glycol monomethyl ether and ethyl acetate, wherein the mass ratio of the distilled water to the n-butyl alcohol to the propylene glycol monomethyl ether to the ethyl acetate is 1: 0.37: 0.1: 0.32, stirring for 15-30 min to uniformly mix; adding tetraethoxysilane, wherein the mass ratio of tetraethoxysilane to distilled water is 1: 0.8, heating to 40-60 ℃ under stirring; dropwise adding a mixed acid solution of hydrochloric acid and acetic acid into the mixed acid solution, wherein after dropwise adding the mixed acid solution for 40-60 min, the mass fraction of the hydrochloric acid in the mixed acid solution is 0.5%, the mass fraction of the acetic acid is 0.5%, and the mass ratio of the hydrochloric acid to the ethyl orthosilicate is 0.1-0.2: 1; stirring and reacting for 2 hours at the temperature of 60-70 ℃, and filtering the materials to obtain the tetraethoxysilane hydrolysate.

Tetraethoxysilane, CAS: 78-10-4, the ethyl orthosilicate of the invention is ethyl orthosilicate-28 available from chemical reagents of national drug group, ltd.

In a preferred embodiment of the present invention, the pigment is selected from any one of red iron oxide, yellow iron oxide, phthalocyanine blue, titanium dioxide, chrome yellow, ultramarine and chromium oxide green.

As a preferred technical scheme of the invention, the wetting dispersant comprises one of a high molecular weight block copolymer solution containing pigment affinity groups, a solution of a low molecular weight unsaturated polycarboxylic acid polymer and polysiloxane copolymer or a mixture thereof.

The toughening agent can further improve the flexibility and adhesion of the coating and improve the impact resistance of the coating, and the toughening agent comprises but is not limited to polyvinyl butyral. The polyvinyl butyral is purchased from Tianjin Daizeng Bingfeng new material Co., Ltd, and has the specification of 8 s.

In a preferred embodiment of the present invention, the thickener is a cellulose ether thickener.

The solid lubricant may be exemplified by MoS₂Graphite powder, talcum powder, polytetrafluoroethylene emulsion and the like.

The metal of the present invention is not limited to any other metal, and examples thereof include steel, iron, alloys, sintered metals, and special surface treatments.

After the solvent type zinc-aluminum coating is coated on the surface of metal, the coating can be naturally placed for 12 hours to be cured; or the coating liquid can be cured by baking, the metal coated with the solvent type zinc-aluminum coating is pre-baked for 10min and cured for 25min at the temperature of 90-120 ℃ and 220-250 ℃, and then naturally cooled to form a film on the sheet. The pre-baking is to volatilize the solvent in the coating liquid, and the temperature is set according to the volatilization point of the solvent used in the coating formula as a reference; if the baking temperature is too low, the volatilization speed of the solvent in the coating liquid is slow, which may cause sagging and uneven thickness of the coating liquid and affect the appearance of the coating; if the baking temperature is too high, the volatilization speed of the solvent in the coating is too high, so that gaps appear, and the performance of the coating is affected.

The solvent type zinc-aluminum coating can be applied to various fields of daily life, and can be listed as follows: the surface protection device comprises parts of automobiles and motorcycles, high-grade parts of daily household appliances, electronic products, communication equipment and the like, metal parts such as rails, screws and bolts of subways and tunnels, metal structural parts of expressway baffles, elevated roads, bridges and the like, cross arms of iron towers and electric poles of high-voltage transmission lines, iron supporting clamp hoops, elbows, bolts, steel caps, oil tanks and fasteners on transformers, and surface protection of hardware tools such as screws, nuts, gaskets and the like.

Besides, the solvent-based zinc-aluminum coating can also be applied to the industries of municipal engineering, mechanical motors, railway docks, shipbuilding and ship repairing, building decoration, aerospace, ocean engineering, geological drilling, petrochemical industry, agricultural science and technology, bioengineering, medical appliances and the like.

The invention uses MoS₂And the isocyanate group terminated hyperbranched polyurethane is used as an anti-settling agent, so that the stability of the coating is enhanced, all components can be fully mixed, and the phenomena of coating aggregation, uneven dispersion and the like are avoided. The hyperbranched polymer mainly comprises a branched part, more branched points, compact spherical structure of molecules, small hydrodynamic radius of gyration, less molecular chain entanglement, and small influence on viscosity caused by the increase of relative molecular mass. The solvent type zinc-aluminum coating added with the isocyanate-terminated hyperbranched polyurethane has high solid content and low viscosity, is suitable for brushing and spraying, and the hyperbranched macromolecules have more excellent ultraviolet resistance, so that the service life of the coating is prolonged. In an organic solvent, the isocyanate group-terminated hyperbranched polyurethane can be well dispersed, and the terminal isocyanate group can react with a corrosion product which is not completely removed from the surface of the base material to generate a hard cured coating and replace water. The isocyanate group terminated hyperbranched polyurethane can be crosslinked with n-butyl silicate and a coupling agent to form a compact crosslinking network, so that the corrosion resistance of the coating is enhanced. The isocyanate group terminated hyperbranched polyurethane contains a plurality of branched chains, can effectively improve the impact resistance and the flexibility of the coating, can further prolong the path of a corrosive medium reaching the surface of a substrate, and enhances the corrosion resistance.

The filler of the invention adopts a plurality of composite fillers to compound, fully utilizes the advantages of various different fillers, improves the rheological property and the storage stability of the coating, improves the corrosion resistance of the coating and is beneficial to reducing the cost. The furan resin modified graphene can effectively enhance the toughness of the coating, and in the process of mixing the component A and the component B, the furan resin modified graphene, the isocyanate group-terminated hyperbranched polyurethane and the coupling agent can be crosslinked with tetraethoxysilane to participate in the curing process, so that the compactness of the coating is further improved, and the mechanical barrier effect of the coating is enhanced. In addition, the isocyanate-terminated hyperbranched polyurethane, the furan resin modified graphene, other fillers and coupling agents can accelerate the curing of the ethyl orthosilicate, and the compounding of various components enables the solvent-based zinc-aluminum coating to be rapidly cured under the conditions of low temperature and low humidity, so that the application range of the solvent-based zinc-aluminum coating is expanded. The furan resin modified graphene and other fillers have good electronic conductivity, the conductivity of the coating is reduced, and the cathode protection capability of the coating is improved.

The present invention will be specifically described below by way of examples. It should be noted that the following examples are only for illustrating the present invention and should not be construed as limiting the scope of the present invention, and that the insubstantial modifications and adaptations of the present invention by those skilled in the art based on the above disclosure are still within the scope of the present invention.

In addition, the starting materials used are all commercially available, unless otherwise specified.

Example 1:

embodiment 1 provides a solvent-based zinc-aluminum coating, which is prepared from a component A and a component B in a mass ratio of 4: 1, mixing; the component A comprises the following components in parts by weight: 75 parts of zinc-aluminum alloy powder, 15 parts of organic solvent, 3 parts of filler, 0.2 part of coupling agent and 0.3 part of anti-settling agent; the component B is tetraethoxysilane hydrolysate; the anti-settling auxiliary agent is MoS₂And isocyanate-terminated hyperbranched polyurethane, said MoS₂And isocyanate group-terminated hyperbranched polyurethane in a mass ratio of5：1。

The zinc-aluminum alloy powder is flaky, the particle size is 500-800 meshes, and the aluminum content in the zinc-aluminum alloy powder is 10 wt%; the organic solvent is n-butyl alcohol; the filler is a mixture of modified graphene, talcum powder, zinc oxide and hydrotalcite, and the mass ratio of the modified graphene to the talcum powder to the zinc oxide to the hydrotalcite is 0.2: 3: 1: 3: 0.3; the coupling agent is gamma-aminopropyl triethoxysilane.

The preparation method of the isocyanate group-terminated hyperbranched polyurethane at least comprises the following steps:

Isophorone diisocyanate, CAS: 4098-71-9 available from Shanghai Michelin Biochemical technology, Inc.

The preparation method of the tetraethoxysilane hydrolysate at least comprises the following steps:

adding distilled water into a mixed solution of n-butyl alcohol, propylene glycol monomethyl ether and ethyl acetate, wherein the mass ratio of the distilled water to the n-butyl alcohol to the propylene glycol monomethyl ether to the ethyl acetate is 1: 0.37: 0.1: 0.32, stirring for 25min to mix evenly; adding tetraethoxysilane, wherein the mass ratio of tetraethoxysilane to distilled water is 1: 0.8, heating to 50 ℃ under stirring; dropwise adding a mixed acid solution of hydrochloric acid and acetic acid, and after 55min of dropwise adding, wherein the mass fraction of the hydrochloric acid in the mixed acid solution is 0.5%, the mass fraction of the acetic acid is 0.5%, and the mass ratio of the hydrochloric acid to the tetraethoxysilane is 0.16: 1; stirring and reacting for 2h at 65 ℃, and filtering the material to obtain the tetraethoxysilane hydrolysate.

The preparation method of the solvent-type zinc-aluminum coating at least comprises the following steps:

a. adding zinc-aluminum alloy powder, an organic solvent, a filler, a coupling agent and an anti-settling agent into a container according to the parts by weight, stirring for 1h, and dispersing and mixing uniformly to obtain a component A;

b. and (B) mixing the component A and the component B obtained in the step a according to a ratio, and stirring for 0.5h to obtain the solvent type zinc-aluminum coating.

Example 2:

embodiment 2 provides a solvent-based zinc-aluminum coating, which is prepared from a component A and a component B in a mass ratio of 5: 1, mixing; the component A comprises the following components in parts by weight: 90 parts of zinc-aluminum alloy powder, 18 parts of organic solvent, 12 parts of filler, 0.7 part of coupling agent and 0.9 part of anti-settling agent; the component B is tetraethoxysilane hydrolysate; the anti-settling auxiliary agent is MoS₂And isocyanate-terminated hyperbranched polyurethane, said MoS₂And the isocyanate group-terminated hyperbranched polyurethane in a mass ratio of 5: 1.

the zinc-aluminum alloy powder is flaky, the particle size is 500-800 meshes, and the aluminum content in the zinc-aluminum alloy powder is 30 wt%. The organic solvent is n-butyl alcohol; the filler is a mixture of modified graphene, talcum powder, zinc oxide and hydrotalcite, and the mass ratio of the modified graphene to the talcum powder to the zinc oxide to the hydrotalcite is 0.2: 3: 1: 3: 0.3; the coupling agent is gamma-aminopropyl triethoxysilane.

The preparation method of the isocyanate group-terminated hyperbranched polyurethane is the same as that of example 1.

The preparation method of the tetraethoxysilane hydrolysate is the same as that of the example 1.

The preparation method of the solvent-based zinc-aluminum coating is the same as that of the example 1.

Example 3:

embodiment 3 provides a solvent-based zinc-aluminum coating, which is prepared from a component A and a component B in a mass ratio of 4.8: 1, mixing; the component A comprises the following components in parts by weight: 86 parts of zinc-aluminum alloy powder, 16 parts of organic solvent, 8 parts of filler, 0.6 part of coupling agent and 0.5 part of anti-settling agent; the component B is tetraethoxysilane hydrolysate; the anti-settling auxiliary agent is MoS₂And isocyanate-terminated hyperbranched polyurethane, said MoS₂And the isocyanate group-terminated hyperbranched polyurethane in a mass ratio of 5: 1.

Example 4:

embodiment 4 provides a solvent-based zinc-aluminum coating, which is prepared from a component a and a component B in a mass ratio of 4.8: 1, mixing; the component A comprises the following components in parts by weight: 86 parts of zinc-aluminum alloy powder, 16 parts of organic solvent, 8 parts of filler, 0.6 part of coupling agent and 0.5 part of anti-settling agent; the component B is tetraethoxysilane hydrolysate; the anti-settling auxiliary agent is MoS₂And isocyanate-terminated hyperbranched polyurethane, said MoS₂And the isocyanate group-terminated hyperbranched polyurethane in a mass ratio of 9: 1.

the zinc-aluminum alloy powder is flaky, the particle size is 500-800 meshes, and the aluminum content in the zinc-aluminum alloy powder is 30 wt%. The organic solvent is ethylene glycol monoethyl ether acetate; the filler is a mixture of modified graphene, talcum powder, zinc oxide and hydrotalcite, and the mass ratio of the modified graphene to the talcum powder to the zinc oxide to the hydrotalcite is 0.2: 3: 1: 3: 0.3; the coupling agent is gamma-aminopropyl triethoxysilane.

Example 5:

embodiment 5 provides a solvent-based zinc-aluminum coating, which is prepared from a component A and a component B in a mass ratio of 4.8: 1, mixing; the component A comprises the following components in parts by weight: 86 parts of zinc-aluminum alloy powder, 16 parts of organic solvent, 8 parts of filler, 0.6 part of coupling agent and 0.5 part of anti-settling agent; the component B is tetraethoxysilane hydrolysate; the anti-settling auxiliary agent is MoS₂And isocyanate-terminated hyperbranched polyurethane, said MoS₂And the isocyanate group-terminated hyperbranched polyurethane in a mass ratio of 8: 1.

Example 6:

example 6 provides a solvent-borne zinc-aluminum coating comprising component A and component BAccording to the mass ratio of 4.8: 1, mixing; the component A comprises the following components in parts by weight: 86 parts of zinc-aluminum alloy powder, 16 parts of organic solvent, 8 parts of filler, 0.6 part of coupling agent and 0.5 part of anti-settling agent; the component B is tetraethoxysilane hydrolysate; the anti-settling auxiliary agent is MoS₂And isocyanate-terminated hyperbranched polyurethane, said MoS₂And the isocyanate group-terminated hyperbranched polyurethane in a mass ratio of 8: 1.

the zinc-aluminum alloy powder is flaky, the particle size is 500-800 meshes, and the aluminum content in the zinc-aluminum alloy powder is 30 wt%. The organic solvent is ethylene glycol monoethyl ether acetate; the filler is a mixture of modified graphene, talcum powder, zinc oxide and hydrotalcite, and the mass ratio of the modified graphene to the talcum powder to the zinc oxide to the hydrotalcite is 0.5: 3: 4: 0.7; the coupling agent is gamma-aminopropyl triethoxysilane.

The modified graphene is furan resin modified graphene.

The preparation method of the modified graphene at least comprises the following steps:

a. adding dissolved K into lithotripsy ink₂S₂O₈And P₂O₅In 18mol/L sulfuric acid solution at 80 ℃, graphite powder and K₂S₂O₈、P₂O₅And sulfuric acid in a mass ratio of 2: 1: 1: 5, stirring, naturally cooling to room temperature, diluting with deionized water, filtering, washing with water to neutrality, and airing the product in the air; adding the product into 18mol/L sulfuric acid in an ice bath, and gradually adding KMnO in the process of stirring₄Graphite powder, sulfuric acid and KMnO₄The mass ratio of (1): 36: 3, controlling the reaction temperature within 15 ℃; then transferring the mixture into a water bath at 35 ℃, gradually adding deionized water, wherein the mass of the deionized water is 45 times that of the graphite powder,stirring and reacting for 2 h; and then adding deionized water and 30 wt% of hydrogen peroxide to terminate the reaction, wherein the mass ratio of the graphite powder to the deionized water to the 30 wt% of hydrogen peroxide is 1: 140: 3, filtering, washing with 3.7 wt% hydrochloric acid to remove metal ions, centrifugally separating, and drying at 50 ℃ for 12 hours to obtain a product a;

b. and (3) dissolving the product a in furfuryl alcohol, wherein the mass ratio of the product a to the furfuryl alcohol is 1: 75, performing ultrasonic treatment for 6 hours; then adding acetic acid, wherein the mass ratio of the acetic acid to the furfuryl alcohol is 0.4: 1, stirring for 1.2 h; adding the furoyl, wherein the mass ratio of the furoyl to the furfuryl alcohol is 1: 0.45, reacting for 4 hours at 106 ℃; stopping heating, naturally cooling the mixture, adding ethylenediamine to adjust the pH value to 7, performing vacuum dehydration to reduce the water content of the product to below 2%, and cooling to 30 ℃ to obtain the modified graphene.

Example 7:

embodiment 7 provides a solvent-based zinc-aluminum coating, which is prepared from a component A and a component B in a mass ratio of 4.8: 1, mixing; the component A comprises the following components in parts by weight: 86 parts of zinc-aluminum alloy powder, 16 parts of organic solvent, 8 parts of filler, 0.6 part of coupling agent and 0.5 part of anti-settling agent; the component B is tetraethoxysilane hydrolysate; the anti-settling auxiliary agent is MoS₂And isocyanate-terminated hyperbranched polyurethane, said MoS₂And the isocyanate group-terminated hyperbranched polyurethane in a mass ratio of 8: 1.

the zinc-aluminum alloy powder is flaky, the particle size is 500-800 meshes, and the aluminum content in the zinc-aluminum alloy powder is 30 wt%. The organic solvent is ethylene glycol monoethyl ether acetate; the filler is a mixture of modified graphene, talcum powder, zinc oxide and hydrotalcite, and the mass ratio of the modified graphene to the talcum powder to the zinc oxide to the hydrotalcite is 0.3: 4: 2: 3: 0.5; the coupling agent is gamma-aminopropyl triethoxysilane.

The modified graphene is furan resin modified graphene.

The preparation method of the modified graphene is the same as that of example 6.

Example 8:

the specific implementation manner of the embodiment 8 is the same as that of the embodiment 7, except that the solvent-based zinc-aluminum coating further comprises 0.6 part by weight of a toughening agent, and the toughening agent is polyvinyl butyral. The polyvinyl butyral is purchased from Tianjin Daizeng Bingfeng new material Co., Ltd, and has the specification of 8 s.

Comparative example 1:

the embodiment of comparative example 1 is the same as that of example 8, except that the anti-settling additive is MoS₂。

Comparative example 2:

the embodiment of comparative example 2 is the same as that of example 8, except that the anti-settling assistant is isocyanate group-terminated hyperbranched polyurethane.

Comparative example 3:

the embodiment of comparative example 3 is the same as that of example 8, except that the anti-settling additive is MoS₂And isocyanate-terminated hyperbranched polyurethane, said MoS₂And the isocyanate group-terminated hyperbranched polyurethane in a mass ratio of 3: 1.

comparative example 4:

comparative example 4 the embodiment is the same as example 8, except that the isocyanate group-terminated hyperbranched polyurethane is replaced by a mixture of equal mass of isophorone diisocyanate and glycerol, the molar ratio of isocyanate groups to hydroxyl groups being 2: 1.

comparative example 5:

the embodiment of comparative example 5 is the same as example 8 except that the filler does not include modified graphene.

Comparative example 6:

the embodiment of comparative example 6 is the same as example 8 except that the modified graphene is replaced with graphene, i.e., the method for preparing the modified graphene does not include step b.

Comparative example 7:

the embodiment of comparative example 7 is the same as that of example 8, except that the modified graphene is replaced by a mixture of graphite powder, furfuryl alcohol and furoyl, and the mass ratio of the graphite powder, the furfuryl alcohol and the furoyl is the same as the stoichiometric ratio used in the synthesis process of the modified graphene.

Performance evaluation:

the test specimens used were tinplate, 40mm by 3mm in size. The sample is pretreated to remove grease, rust and oxides from the surface of the sample before the paint is applied to the surface of the sample. In this test, grease on the surface of a sample was removed by using a phosphorus-free degreasing and degreasing cleaning solution (manufactured by Shanghai Yao chemical Co., Ltd.), and then, rust and oxides on the surface of the sample were removed by shot blasting.

In this test, air spraying was performed using a PE2090 type air compressor and a PQ-2 type spray gun, and the air pressure: 0.6 MPa; the distance between the nozzle of the spray gun and the sample is about 30 cm.

Curing time

And (3) putting the sprayed sample into a wet heat box for curing, wherein the parameters of the wet heat box are as follows: 15 ℃ and a relative humidity of 40%. The open and close times of the coatings obtained using the solvent-based zinc-aluminum coatings described in examples 1 to 8 and comparative examples 1 to 7 were recorded according to the national standard "GBT 201728-1979 paint film/putty film drying time assay".

The following tests were carried out on the performance of the coatings obtained with the solvent-based zinc-aluminum coatings described in examples 1 to 8 and comparative examples 1 to 7 after the coatings were completely dried. The sample can be naturally dried by naturally placing the sample for more than 12 hours; or curing and drying the sample by baking, pre-baking the metal coated with the solvent type zinc-aluminum coating for 10min and curing for 25min at the temperature of 120 ℃ and 260 ℃, and naturally cooling to obtain the dried coating.

Adhesion force

The coating adhesion test is carried out according to GB/T9286-1998 standard, 5 parallel cutting lines are vertically and horizontally cut on a sample by a cutting tool in a crossed mode, the distance is 6mm, the cut part of the coating is pasted by transparent adhesive tape, the adhesive tape is uniformly torn off, the damage condition of the cut coating is checked, the test result is 0-5 grade, the 0 grade is intact, and the first three grades are qualified for general use.

Level 0: the cutting edge is completely smooth, and no lattice falls off;

level 1: the coating has little sheet separation at the cutting intersection, and the affected area of the grid-marking area is not more than 5%;

and 2, stage: the area of the coating at the edge or intersection of the cut that is peeled off is greater than 5%, but not greater than 15%;

and 3, level: partial peeling or whole-piece peeling along the edge of the cut, or partial lattices are peeled by whole pieces, and the peeling area is more than 15 percent but less than 35 percent;

4, level: the cut edge is largely peeled off or some squares are partly or totally peeled off, and the area of the cut edge is more than 35% of the area of the grid-cutting area but less than 65%;

and 5, stage: the coating layer with pieces falls off at the edge and the intersection of the scribing line, and the total falling area is more than 65 percent.

Flexibility

The flexibility refers to the cracking resistance or stripping resistance of the paint and varnish coating from the substrate when the paint and varnish coating is bent around a cylinder under standard conditions, is one of the main indexes for measuring the performance of the paint, and has great reference value for the selection and application of the paint variety. The test is carried out according to the national standard GB/T1731-93 coating film flexibility determination method. The test method comprises the following steps: with a predetermined round bar, the diameter of the round bar is 6 kinds such as 1mm, 2mm, 3mm, 4mm, 5mm, 10mm by 90 degrees of bending, and the smaller the bending diameter is, the larger the elongation (flexibility) of the coating film is. The flexibility of the coating is generally required to be 1 to 3 mm. When the flexibility is measured, the phenomena of cracks, reticulate patterns, peeling and the like can be observed by using a 4-time magnifying glass, and if no abnormal sample exists, the product is qualified. The diameter of the round bar used when passing was recorded.

Corrosion resistance

The neutral salt spray test method is a manual accelerated salt spray environment simulation test method which has the widest application range at present and is suitable for testing the corrosion resistance of metals and alloys thereof, metal covering layers, organic covering layers, anodic oxide films and conversion films. The neutral salt spray test was conducted in a salt spray test chamber of type HS-101B.

The specific operation is carried out according to the specification of metal protective layer-neutral salt spray test (NSS test) in International Standard ISO3768-1976, wherein an aqueous NaCl solution with the concentration of 5 +/-0.5 wt% and the pH value of 6.5-7.2 is adopted, the test temperature is 35 +/-2 ℃, the humidity is more than 95%, and the nozzle pressure is 0.7-1 kgf cm^-2The mist reduction amount is 1-2 mL/(80 cm)²H). And after the test is finished, taking out the sample, naturally drying the sample indoors for 0.5-1 h before cleaning the sample, then slightly cleaning the sample by using tap water to remove residual salt mist solution on the surface of the sample, immediately drying the sample by using a blower, and observing the corrosion appearance of the coating.

Due to the limitation of time and experimental conditions, the coating sample is subjected to scribing treatment in a neutral salt spray test, then the coating sample is put into a salt spray box for accelerated corrosion, and the corrosion condition of the sample after 60 days is used as an evaluation standard of corrosion resistance. And (4) inspecting the corrosion resistance of the coating according to the difference of the corrosion degrees of the samples in the same time. The total corrosion resistance is no corrosion, the total corrosion resistance is 10 minutes without foaming, the total corrosion resistance is 0 minutes, and the other corrosion resistance is sequentially rated as 1-9 minutes.

Table 1 performance characterization test

As can be seen from Table 1, the solvent-based zinc-aluminum coating disclosed by the invention has very excellent performance, can be quickly dried at a lower temperature and humidity, and has the advantages of good coating adhesion, good flexibility and excellent corrosion resistance.

The foregoing examples are merely illustrative and serve to explain some of the features of the method of the present invention. The appended claims are intended to claim as broad a scope as is contemplated, and the examples presented herein are merely illustrative of selected implementations in accordance with all possible combinations of examples. Accordingly, it is applicants' intention that the appended claims are not to be limited by the choice of examples illustrating features of the invention. Also, where numerical ranges are used in the claims, subranges therein are included, and variations in these ranges are also to be construed as possible being covered by the appended claims.

Claims

1. The solvent type zinc-aluminum coating is characterized by comprising a component A and a component B in a mass ratio of 4: 1-5: 1, mixing; the component A comprises the following components in parts by weight: 75-90 parts of zinc-aluminum alloy powder, 15-18 parts of organic solvent, 3-12 parts of filler, 0.2-0.7 part of coupling agent and 0.3-0.9 part of anti-settling agent; the component B is tetraethoxysilane hydrolysate; the anti-settling agent is MoS₂And isocyanate-terminated hyperbranched polyurethane, said MoS₂And the isocyanate group-terminated hyperbranched polyurethane in a mass ratio of 5-9: 1; the filler is a mixture of modified graphene, talcum powder, zinc oxide and hydrotalcite, and the mass ratio of the modified graphene to the talcum powder to the zinc oxide to the hydrotalcite is 0.2-0.5: 1-3: 3-4: 0.3 to 0.7; the modified graphene is furan resin modified graphene.

2. The solvent-borne zinc-aluminum coating of claim 1 wherein said organic solvent is selected from the group consisting of ethanol, n-butanol, isopropanol, t-butanol, methyl ethyl ketone, cyclohexanone, butyl acetate, ethylene glycol ethyl ether acetate, ethylene glycol butyl ether, butylene glycol methyl ether, methyl isobutyl ketone, isobutyl acetate, ethyl acetate, octyl acetate, methyl ethyl ketone, methyl isobutyl ketone, methyl hexyl ketone, 120-methyl hexyl ketone^#Solvent oil, 200^#Mineral spirit, D30^#Mineral spirit, D40^#Mineral spirit, D60^#Mineral spirit, D65^#Mineral spirit, D80^#Mineral spirit, D90^#Solvent oil, D100^#Mineral spirit, D110^#Mineral spirit, D130^#Solvent oil, D160^#Any one or more of mineral spirits.

3. The solvent-based zinc aluminum coating of claim 1 wherein the coupling agent is selected from any one or more of silane coupling agents, titanate coupling agents, zirconate coupling agents, and aluminate coupling agents.

4. The solvent-based zinc aluminum coating according to claim 3, wherein the coupling agent is selected from one or more of γ -aminopropyltriethoxysilane, N-phenylaminomethyltriethoxysilane, (3-trimethoxysilylpropyl) diethylethylenediamine, anilinomethyltrimethoxysilane, γ -glycidoxypropyltrimethoxysilane, γ -glycidoxypropyltriethoxysilane, β - (3, 4-epoxycyclohexyl) ethyltrimethoxysilane, 3- (methacryloyloxy) propyltrimethoxysilane, γ -mercaptopropyltrimethoxysilane, γ -mercaptopropylmethyldimethoxysilane, bis- (γ -triethoxysilylpropyl) -tetrasulfide, 3- (methacryloyloxy) propyltrimethoxysilane, vinyltris (2-methoxyethoxy) silane, vinyltrimethoxysilane, isopropyltris (dioctylphosphato) titanate, isopropyldioleaato (dioctylphosphato) titanate, triisopropyltitanate, bis (dioctylphosphato) ethylenephosphate, tetraisopropylbis (dioctylphosphato) phosphite, tetra-N-octyloxypropyl titanate, and distearoyloxy (dioctylphosphato) titanate.

5. The solvent-borne zinc-aluminum coating according to claim 1, further comprising other auxiliary agents selected from one or more of pigments, wetting and dispersing agents, toughening agents, thickeners, leveling aids and solid lubricants.

6. The method for preparing the solvent-based zinc-aluminum coating according to any one of claims 1 to 5, comprising at least the following steps:

7. The use of the solvent-borne zinc-aluminum coating according to any one of claims 1 to 5 in the field of metal surface protection.