CN115975484A - Primer-topcoat water-based coating composition, coating system and application thereof - Google Patents

Abstract

The present application relates to a water-based coating composition with bottom surface integrated, the water-based coating composition comprises: a cross-linkable component and a polyisocyanate curing agent, the cross-linkable component comprises a water-based hydroxyl acrylic resin dispersion, the polyisocyanate The curing agent includes hydrophobic polyisocyanate, and the ratio of NCO groups of the polyisocyanate curing agent to OH groups of the crosslinkable component is (1˜1.6):1. The application can effectively adjust the chemical reaction speed and cross-linking density of the water-based polyurethane bottom-surface-in-one coating. In addition, the present application can also effectively remove bubbles in the process of production and construction, avoiding the problem of bursting bubbles. Furthermore, the present application also improves the salt spray resistance of the coating formed by the water-based coating composition through the reasonable combination of the anti-rust pigment, coloring pigment and filler. The present application also relates to the coating system formed by the water-based coating composition and the application of the water-based coating composition or coating system in product exterior coating.

Description

Water-based coating composition combining bottom and top, coating system and application thereof

Technical Field

The present application relates to the field of coatings, and in particular to a bottom-and-top integrated water-based coating composition, a coating system formed by the water-based coating composition, and the application of the water-based coating composition or coating system in exterior coating of products.

Background Art

Metal corrosion is a phenomenon in which metals are destroyed by chemical or electrochemical effects of environmental media. Metal corrosion is prevalent in all areas of the national economy, causing huge losses to the national economy. The losses caused by corrosion to mankind are staggering. The economic losses caused by corrosion are about 1 trillion US dollars per year, accounting for about 10% of the global total metal output value. In 2008, the economic losses caused by corrosion in my country reached 1.2 trillion to 2 trillion yuan. Therefore, vigorously developing anti-corrosion technology has become a necessary solution to reduce anti-corrosion losses and promote the transformation of a resource-saving society. Applying anti-corrosion coatings on metal surfaces is one of the most effective and commonly used methods for metal surface protection. Anti-corrosion coatings can mainly isolate corrosive media from metal substrates to achieve the purpose of anti-corrosion.

The two-component polyurethane coating is a three-dimensional network structure formed by cross-linking hydroxy acrylic resin and isocyanate curing agent. The unique structure of polyurethane molecules has soft-hard microphase characteristics. The polyurethane molecular chain contains highly polar urethane groups, which have high cohesive energy, and can form hydrogen bonds between molecular chains to form hard segment microphase regions. There are also good soft segments in the polyurethane molecular chain, which are easy to aggregate to form soft phase regions. This unique "hard-soft" microphase structure of polyurethane makes its coating have good adhesion, appearance, chemical resistance, hardness, and excellent wear resistance and weather resistance.

Compared with the traditional oily system, the water-based coating composition with both bottom and top coatings significantly reduces the VOC emitted into the air during the manufacturing, construction, drying, curing and film-forming processes, reducing the pollution and threat to the human ecological environment. Since the polyisocyanate curing agent reacts with water to release carbon dioxide gas, water-based polyurethane is prone to heat rash when spraying high film thickness during construction. The presence of bubbles has a significant negative impact on the salt spray resistance, water resistance, chemical resistance, etc. of the paint film, seriously affecting the quality of the final product.

Although the bottom-to-top integrated water-based coating composition has good weather resistance, appearance, chemical resistance and other characteristics, its anti-corrosion performance is not satisfactory. At present, the most effective solution is to use a water-based epoxy primer coating with a bottom-to-top integrated water-based coating composition to enhance its anti-corrosion performance. This combination is widely used in steel structures, commercial vehicles, construction machinery, rail transit and other fields. In the early stage, our company has issued relevant water-based polyurethane patents (CN 107629652 A and CN 111019504A), but this patent only uses polyurethane as a topcoat and does not have anti-corrosion performance, or improves the anti-corrosion performance of polyurethane topcoat by using an epoxy primer. However, this solution requires two types of coatings, epoxy and polyurethane, for construction. The construction process is relatively complicated and requires different construction equipment.

In view of this, it is necessary to provide a new water-based coating composition and coating system to solve the above-mentioned problems of complex construction and poor salt spray resistance, water resistance, chemical resistance, etc. of the formed paint film.

Summary of the invention

The purpose of the present application is to provide a bottom-and-top integrated water-based coating composition and a coating system formed by the water-based coating composition, so as to solve the problems of high-thickness film prone to bubble bursting, poor corrosion resistance and poor appearance in the construction and application of water-based polyurethane coatings.

In order to achieve the above-mentioned purpose, according to one aspect of the present application, a bottom-and-top integrated aqueous coating composition is provided, comprising: a cross-linkable component and a polyisocyanate curing agent, wherein the cross-linkable component comprises an aqueous hydroxy acrylic resin dispersion, the polyisocyanate curing agent comprises a hydrophobic polyisocyanate, and the ratio of the NCO group of the polyisocyanate curing agent to the OH group of the cross-linkable component is (1 to 1.6):1.

In some embodiments, the mass ratio of the cross-linkable component to the polyisocyanate curing agent is 100:(15-30).

In some embodiments, based on 100 parts by weight of the total cross-linkable component, the cross-linkable component comprises 40-70 parts by weight of the aqueous hydroxyl acrylic resin dispersion.

In some embodiments, based on the solid component, the aqueous hydroxyl acrylic resin dispersion has a hydroxyl value of 100-140 mgKOH/g, a pH value of 6.5-8.5, an acid value of 18-25 mgKOH/g, a number average molecular weight of 5000-10000, and a particle size of 100-200 nm.

In some preferred embodiments, the aqueous hydroxylated acrylic resin dispersion is formed by dispersing an aqueous hydroxylated acrylic resin in water.

In some preferred embodiments, the water-based hydroxyl acrylic resin dispersion contains water-based hydroxyl acrylic resin A, which is obtained by free radical copolymerization of acrylate monomers and vinyl monomers to obtain a polymer with uniform molecular weight distribution and chain segments with active groups that can participate in curing and cross-linking, and further emulsified to obtain a water-based hydroxyl acrylic resin A with a core-shell structure. This resin is a resin produced by Nippon Paint (China) Co., Ltd.

In some preferred embodiments, the aqueous hydroxy acrylic resin dispersion may further include an aqueous hydroxy acrylic resin B. The aqueous hydroxy acrylic resin B is a mixture of one or more commercially available aqueous hydroxy acrylic resins, and is mixed with the aqueous hydroxy acrylic resin A to obtain the aqueous hydroxy acrylic resin dispersion, and the aqueous hydroxy acrylic resin dispersion satisfies the above-mentioned hydroxyl value, pH value, acid value, number average molecular weight and particle size.

6511或

6515的水性羟基丙烯酸树脂，或者万华化学集团股份有限公司的型号为Antkote 2036、Antkote 2035或Antkote2042的水性羟基丙烯酸树脂中的一种或几种的混合。The waterborne hydroxyl acrylic resin B is, for example, but not limited to: waterborne hydroxyl acrylic resins of the type Bayhydrol A 2601, Bayhydrol A 145 or Bayhydrol A 2542 manufactured by Covestro Polymers (China) Co., Ltd.,

6511 or

6515 water-based hydroxyl acrylic resin, or one or a mixture of the water-based hydroxyl acrylic resins of model Antkote 2036, Antkote 2035 or Antkote 2042 of Wanhua Chemical Group Co., Ltd.

In some embodiments, the hydrophobic polyisocyanate is an aliphatic polyisocyanate based on hexamethylene diisocyanate.

In some embodiments, the hydrophobic polyisocyanate is a hexamethylene diisocyanate trimer or an aliphatic polyisocyanate containing hexamethylene diisocyanate. Preferably, the hexamethylene diisocyanate trimer is a hydrophobic hexamethylene diisocyanate asymmetric trimer (HDI).

The hydrophobic polyisocyanate is, for example but not limited to: Asahi Kasei Corporation's products with model numbers of Duranate TLA100, Duranate TUL-100 or Duranate TPA-100, Covestro (China) Co., Ltd.'s products with model numbers of Desmodur N 3900, Desmodur N 3600 or Desmodur 3300, Wanhua Chemical Group Co., Ltd.'s products with model numbers of Wannate HT-100 or Wannate HT-600, BASF (China) Co., Ltd.'s products with model numbers of Basonat HI 100, Basonat HI 190 or Basonat HI 2000, or a mixture of one or more of the products with model numbers of Coronate MPAX-75 or Coronate 2796 of Tosoh Corporation of Japan.

In some embodiments, the polyisocyanate curing agent further comprises a hydrophilic polyisocyanate, and the mass ratio of the hydrophobic polyisocyanate to the hydrophilic isocyanate is (2.5-2.75):1.

In some embodiments, the hydrophilic isocyanate is an aliphatic polyisocyanate based on ifredione diisocyanate.

In some embodiments, the hydrophilic isocyanate is a mixture of one or more of a hydrophilic modified aliphatic polyisocyanate based on isophorone diisocyanate (IPDI), an aliphatic polyisocyanate of an isophorone diisocyanate trimer (IPDI homopolymer), or a hydrophilic aliphatic polyisocyanate based on isophorone diisocyanate (IPDI).

The hydrophilic isocyanate is, for example, but not limited to: a mixture of one or more of the following: a water-based PU curing agent series products of Covestro (China) Co., Ltd. with the model number Bayhydur (for example, Bayhydur 401-60 PGDA or Bayhydur 401-70 PGDA), an aliphatic polyisocyanate based on isophorone diisocyanate trimer (IPDI homopolymer) with the model number Tolonate IDT 70 B of the Perstorp Group, or an water-based curing agent with the model number OS-9402 of Guangzhou Guanzhi New Material Technology Co., Ltd., a hydrophilic aliphatic polyisocyanate based on isophorone diisocyanate (IPDI).

In the present application, by screening the aqueous hydroxy acrylic resin and polyisocyanate curing agent contained in the above-mentioned specific aqueous hydroxy acrylic resin dispersion, the mixing compatibility problem of the cross-linkable component and the polyisocyanate curing agent can be effectively solved, and a bottom-to-top integrated aqueous coating composition with good construction applicability and excellent performance can be obtained.

In some embodiments, the polyisocyanate curing agent further comprises a first solvent, and the mass solid content of the polyisocyanate curing agent is 50-70%.

In some embodiments, the first solvent is selected from at least one of an ester solvent, a ketone solvent, and an aromatic solvent.

In some preferred embodiments, the ester solvent is one or a mixture of butyl acetate, ethyl acetate, propylene glycol methyl ether acetate (PMA), propylene glycol diacetate (PGDA), dibasic acid esters, dipropylene glycol dimethyl ether (DMM) or ethylene carbonate solvents; the ketone solvent is one or a mixture of methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone or methoxyhexanone; the aromatic solvent is one or a mixture of toluene or xylene.

The first solvent is, for example but not limited to: DOWANOLTM PMA, DOWANOLTM PGDA or PROGLYDETM DMM of Dow Chemical (China) Co., Ltd., divalent ester DBE of INVISTA Management (Shanghai) Co., Ltd., or propylene carbonate or alkane solvent oil of Dongying Jinchao Chemical Co., Ltd., or a mixture of them.

In some embodiments, the cross-linkable component further comprises an anti-rust pigment and a coloring pigment, wherein the anti-rust pigment is selected from at least one of composite iron-titanium powder, composite molybdenum-titanium powder, composite hybrid phosphate anti-rust pigment and composite molybdate anti-rust pigment; and the coloring pigment is selected from at least one of titanium dioxide, carbon black, yellow iron oxide, black iron oxide, phthalocyanine blue, organic red, organic yellow and organic orange.

In some embodiments, the cross-linkable component further comprises a filler, and the filler is selected from at least one of talc powder, feldspar powder, barite powder, precipitated barium sulfate and mica powder.

In some embodiments, based on 100 parts by weight of the total cross-linkable component, the sum of the parts by weight of the anti-rust pigment, the coloring pigment and the filler contained in the cross-linkable component is 10 to 40 parts by weight.

In some embodiments, the cross-linkable component further comprises a second solvent, and the second solvent is selected from at least one of ethylene glycol butyl ether, diethylene glycol butyl ether, diethylene glycol ethyl ether acetate, diethylene glycol hexyl ether, diethylene glycol diethyl ether, propylene glycol diacetate, diethylene glycol dibutyl ether, dipropylene glycol dimethyl ether, dipropylene glycol monobutyl ether, tripropylene glycol monobutyl ether solvent and alkane solvent oil. Wherein, the alkane solvent oil is one or a mixture of 100#, 120#, 150#, and 200# solvent oils.

In some embodiments, the cross-linkable component comprises 3 to 10 parts by mass of the second solvent based on 100 parts by mass of the total cross-linkable component.

In some embodiments, the crosslinkable component further comprises an auxiliary agent, wherein the auxiliary agent is selected from at least one of a dispersant, a defoamer, a substrate wetting agent, a rheological additive, an anti-flash rust agent, an ultraviolet light absorber, and a hindered amine light stabilizer.

In some embodiments, the cross-linkable component comprises 4 to 14 parts by mass of an auxiliary agent based on 100 parts by mass of the total cross-linkable component.

In some embodiments, based on 100 parts by weight of the total cross-linkable component, the auxiliary agent included in the cross-linkable component includes the following components:

In the present application, by using the components of the auxiliary agent in the above-mentioned specific proportion range in combination, the bubbles generated during the production and construction process can be further effectively removed, thereby avoiding the problem of bubble bursting in the coating during the construction process.

The dispersant may be, for example but not limited to, TEGO Dispers 755W or TEGODispers 757W series products of Evonik Industries, Dispex Ultra PA 4560, Dispex Ultra PX 4585 or Dispex Ultra PX 4575 series products of BASF (China) Co., Ltd., DISPRBYK-2061, DISPRBYK-2055, DISPERBYK-191 or DISPERBYK-2010 series products of BYK, or Solsperse W100 or Solsperse W400 products of Lubrizol Management (Shanghai) Co., Ltd., or a mixture of several of them.

In some embodiments, the defoaming agent comprises a polydimethylsiloxane defoaming agent and an acetylenic diol defoaming agent.

The polydimethylsiloxane defoamer is, for example, but not limited to, one or a mixture of TEGO Airex902W, TEGO Foamex 810, TEGO Foamex 815N or TEGO Foamex 825 of Evonik Industries, or BYK 024 or BYK 028 of BYK. The acetylene glycol defoamer is, for example, but not limited to, one or a mixture of SURFYNOL AD01, SURFYNOL AD01, SURFYNOL 104BC, SURFYNOL 420, SURFYNOL 107L or SURFYNOL 440 of Evonik Industries.

In some embodiments, the substrate wetting agent is an organo-modified siloxane, which is effective in reducing surface tension.

The substrate wetting agent is, for example but not limited to: BYK 345, BYK 346 or BYK 349 from BYK, or a mixture of one or more of TEGO Wet 240, TEGO Twin 4100, TEGO Wet 270 and DYNOL 360 from Evonik Industries.

In some embodiments, the rheological additive is a nonionic polyurethane associative thickener, which can effectively adjust the viscosity of low shear and high shear. The nonionic polyurethane associative thickener is obtained by nonionic hydrophobic modification. In the present application, the rheological additive can effectively adjust the low shear viscosity and high shear viscosity during the construction process, and can improve the rheological behavior during the construction process.

The rheological additive may be, for example but not limited to: ACRYSOL RM-998, ACRYSOL RM-8W, ACRTSOL RM-2020NPR or ACRYSOL RM-12W produced by Dow Chemical (China) Co., Ltd., or one or a mixture of DeuRheo WT-105A, RHEOLATE 350D, DeuRheo WT-108F, RHEOLATE 299 produced by Hemmings New Materials Technology Co., Ltd.

The anti-flash rust agent is, for example but not limited to: FlashProTAC F2M, FlashproTAC C4E of Shanghai Xiaogeng New Material Technology Co., Ltd., or Halox 515, Halox350, Halox 330 of Shanghai Pengpan Trading Co., Ltd., or ASCOTRAN H10, ASCOTRAN H14 of Ascodi, France, or at least one or more of them.

The applicant needs to explain that, since the bottom-to-top integrated water-based coating composition described in the present application is still wet when directly applied on the iron/steel substrate, rapid corrosion will occur, thereby generating flash rust. However, long-term corrosion inhibitors such as anti-rust pigments are not suitable for preventing the generation of such flash rust, so in the present application, the anti-flash rust agent in aqueous solution is used.

The ultraviolet light absorber is, for example but not limited to: EVERSORB AQ1 or EVERSORB AQ3 produced by Taiwan Everlight Chemical Industry Co., Ltd., or one or a mixture of TINUVIN 99DW(N), TINUVIN1130 or TINUVIN 123DW(N) produced by BASF (China) Co., Ltd.

The hindered amine light stabilizer is, for example but not limited to: EVERSORB 93 produced by Taiwan Everlight Chemical Industry Co., Ltd., or one or a mixture of products of TINUVIN 477DW (N), TINUVIN 292, and TINUVIN 400DW (N) produced by BASF (China) Co., Ltd.

In the present application, the reasonable combination of the ultraviolet absorber and the hindered amine light stabilizer enables the coating formed by the bottom-to-top integrated water-based coating composition of the present application to have good weather resistance.

In a preferred embodiment of the present application, a bottom-surface integrated water-based coating composition is provided, comprising: a cross-linkable component and a polyisocyanate curing agent, wherein the ratio of the NCO group of the polyisocyanate curing agent to the OH group of the cross-linkable component is (1-1.6):1; wherein,

The cross-linkable component comprises the following components, calculated based on 100 parts by weight of the total cross-linkable component:

Based on the solid component, the aqueous hydroxy acrylic resin dispersion has a hydroxyl value of 100 to 140 mgKOH/g, a pH value of 6.5 to 8.5, an acid value of 18 to 25 mgKOH/g, a number average molecular weight of 5000 to 10000, and a particle size of 100 to 200 nm;

The polyisocyanate curing agent comprises a hydrophobic polyisocyanate, and the hydrophobic polyisocyanate is an aliphatic polyisocyanate based on hexamethylene diisocyanate;

The polyisocyanate curing agent further comprises a first solvent, and the mass solid content of the polyisocyanate curing agent is 50 to 70%;

The pigment comprises an anti-rust pigment and a coloring pigment; the anti-rust pigment is selected from at least one of composite iron-titanium powder, composite molybdenum-titanium powder, composite hybrid phosphate anti-rust pigment and composite molybdate anti-rust pigment; the coloring pigment is selected from at least one of titanium dioxide, carbon black, yellow iron oxide, black iron oxide, phthalocyanine blue, organic red, organic yellow and organic orange;

The filler is selected from at least one of talc powder, feldspar powder, barite powder, precipitated barium sulfate and mica powder.

In the above embodiment, based on the total mass of the cross-linkable component being 100 parts, the auxiliary agent contained in the cross-linkable component includes the following components:

In the bottom-surface integrated water-based coating composition of the present application, firstly, by adjusting the specific ratio of the water-based hydroxy acrylic resin and the polyisocyanate curing agent in the water-based hydroxy acrylic resin dispersion, that is, the specific ratio of the NCO group of the polyisocyanate curing agent to the OH group of the cross-linkable component, the chemical reaction rate and cross-linking density of the water-based polyurethane bottom-surface integrated coating can be effectively adjusted. Secondly, by the specific selection of the water-based hydroxy acrylic resin contained in the water-based hydroxy acrylic resin dispersion and the specific selection of the polyisocyanate curing agent, in combination with the specific ratio of the water-based hydroxy acrylic resin and the polyisocyanate curing agent, the bubbles in the production and construction process can be effectively removed, avoiding the problem of bubble bursting in the coating formed by the bottom-surface integrated water-based coating composition of the present application during the construction process. Furthermore, by the reasonable combination of the anti-rust pigment, the coloring pigment and the filler, the salt spray resistance of the coating formed by the bottom-surface integrated water-based coating composition of the present application is improved.

It will be understood by those skilled in the art that the base-top integrated water-based coating composition described in the present application can be directly used for external coating of products as a topcoat of the product without the need for an additional layer of primer.

Therefore, according to another aspect of the present application, a coating system is also provided, comprising a coating formed by any one of the above-mentioned bottom-to-bottom integrated aqueous coating compositions.

Of course, those skilled in the art will appreciate that the base-top integrated water-based coating composition described in the present application may also be used for internal coating of products, as a primer or mid-coat.

Therefore, in some embodiments, the coating system described in the present application may further include a topcoat layer or a primer layer.

In some embodiments, the primer-top integrated water-based coating composition described in the present application can be matched with a one-component epoxy primer, a two-component epoxy primer, or an acrylic system.

In some embodiments, the coating formed by the bottom-to-bottom integrated aqueous coating composition described in the present application can match the sandblasted steel plate.

According to another aspect of the present application, there is also provided the use of any one of the above-mentioned bottom-and-top integrated aqueous coating compositions or any one of the above-mentioned coating systems in the external or internal coating of a product.

The present application provides a bottom-surface integrated water-based coating composition and a coating formed therefrom, and through the above-described specific ratio matching specific practical selection, the water-based coating composition described in the present application and the coating formed therefrom have performances different from existing conventional coating compositions, and have good construction operability and final coating performance. The bottom-surface integrated water-based coating composition described in the present application and the coating formed therefrom are simple to operate, and also have a wide range of construction applications, and can maintain a high bubble film thickness at room temperature, high temperature, especially under conditions such as high temperature and low humidity, high temperature and high humidity, and are very suitable for industrial production. At the same time, the bottom-surface integrated water-based coating composition described in the present application forms a coating with a three-dimensional cross-linked network structure after coating and baking, and this coating has good salt spray resistance and water resistance, and also has excellent appearance and high weather resistance, and can be applied to industrial protection fields such as steel structures, commercial vehicles, and construction machinery.

DETAILED DESCRIPTION

The technical solution of the present application is described below in conjunction with some specific embodiments. Those skilled in the art should understand that the specific description below is illustrative rather than restrictive, and should not be used to limit the scope of protection of the present invention.

Unless otherwise specified, the various raw materials of the present application are commercially available or prepared according to conventional methods in the art. Unless otherwise specified, all professional and scientific terms used in the present application have the same meanings as those familiar to those skilled in the art. Any method or material similar to the described content can be applied in the present application method.

According to a specific embodiment of the present application, a bottom-and-top integrated water-based coating composition is provided.

The bottom-to-top integrated water-based coating combination comprises a cross-linkable component and a polyisocyanate curing agent, wherein, based on 100 parts by weight of the total cross-linkable component, the cross-linkable component comprises the following components:

The ratio of the NCO group of the polyisocyanate curing agent to the OH group of the crosslinkable component is (1-1.6):1; or, the mass ratio of the crosslinkable component to the polyisocyanate curing agent is 100:(15-30).

In this embodiment, based on the solid component, the aqueous hydroxy acrylic resin dispersion has a hydroxyl value of 100 to 140 mgKOH/g, a pH value of 6.5 to 8.5, an acid value of 18 to 25 mgKOH/g, a number average molecular weight of 5000 to 10000, and a particle size of 100 to 200 nm. The polyisocyanate curing agent comprises a hydrophobic polyisocyanate, which is an aliphatic polyisocyanate based on hexamethylene diisocyanate. Alternatively, the polyisocyanate curing agent is a mixture of the hydrophobic polyisocyanate and the hydrophilic polyisocyanate.

Therefore, in this embodiment, screening the appropriate aqueous hydroxy acrylic resin dispersion and the polyisocyanate curing agent can effectively solve the mixing compatibility problem of the cross-linkable component and the polyisocyanate curing agent, and obtain a bottom-and-top integrated aqueous coating combination with good construction applicability and excellent performance.

In this embodiment, the pigment includes an anti-rust pigment and a coloring pigment; the anti-rust pigment is one or a mixture of composite iron titanium powder, composite molybdenum titanium powder, composite hybrid phosphate anti-rust pigment and composite molybdate anti-rust pigment; the coloring pigment is one or a mixture of titanium dioxide, carbon black, yellow iron oxide, black iron oxide, phthalocyanine blue, organic red, organic yellow and organic orange. The filler is one or a mixture of talc powder, feldspar powder, barite powder, precipitated barium sulfate and mica powder.

In this embodiment, the second solvent is one or more of ethylene glycol butyl ether, diethylene glycol butyl ether, diethylene glycol ethyl ether acetate, diethylene glycol hexyl ether, diethylene glycol diethyl ether, propylene glycol diacetate, diethylene glycol dibutyl ether, dipropylene glycol dimethyl ether, dipropylene glycol monobutyl ether, tripropylene glycol monobutyl ether solvent and alkane solvent oil. The alkane solvent oil is one or more of 100#, 120#, 150#, 200# solvent oil.

In this embodiment, based on the total mass of the cross-linkable component being 100 parts, the auxiliary agent contained in the cross-linkable component includes the following components:

The specific selection ranges of all components included in the bottom-top integrated water-based coating composition provided in this embodiment are described in detail above and will not be repeated here.

Example 1

In this embodiment, a bottom-surface integrated water-based coating composition is provided, the water-based coating composition comprising: a cross-linkable component and a polyisocyanate curing agent;

The cross-linkable component is composed of the following components in terms of mass percentage:

The first solvent of the polyisocyanate curing agent is propylene glycol diacetate (PGDA); wherein:

The aqueous hydroxy acrylic resin dispersion is obtained by free radical copolymerization of acrylate monomers and vinyl monomers to obtain a polymer with uniform molecular weight distribution and active groups in the chain segments that can participate in curing and crosslinking. The polymer is further neutralized and emulsified to obtain an aqueous hydroxy acrylic resin dispersion with low solvent content, high solid content, and a core-shell structure. Based on the solid component, the aqueous hydroxy acrylic resin dispersion has a hydroxyl value of 100-130 mgKOH/g, a pH value of 6.5-8.5, a particle size of 100-200 nm, a solid acid value of 18-25 mgKOH/g, and a number average molecular weight of about 5000-10000. This resin is a self-produced resin of Nippon Paint (China) Co., Ltd.

The coloring pigment is 23.0 parts of TI-PURE R-960 titanium dioxide and 1.0 parts of MITSUBISHI CARBON BLACKMA-100 carbon black. The anti-rust pigment is Nubirox 102. The filler is sub-nano precipitated barium sulfate. The dispersant is Dispex Ultra PX 4560. The second solvent is 2.0 parts of ethylene glycol butyl ether, 2.0 parts of diethylene glycol butyl ether, and 2.0 parts of alkane 200# solvent oil. The defoamer is 0.5 parts of TEGO Foamex 810 defoamer and 0.5 parts of SURFYNOL AD01 defoamer. The substrate wetting agent is BYK 346. The rheological additive is 0.5 parts of ACRTSOL RM-8W and 0.5 parts of ACRTSOLRM-2020NPR. The anti-flash rust agent is FlashproTAC C4E. The ultraviolet light absorber and the hindered amine light stabilizer are TINUVIN1130 and TINUVIN292 respectively.

The mass solid content of the polyisocyanate curing agent is 62wt%, and the polyisocyanate curing agent is a mixture of hydrophobic Wannate HT-600 and hydrophilic curing agent Bayhydur 401-60PGDA, with the proportions of the two being 50 parts and 20 parts respectively.

The mass ratio of the cross-linkable component to the polyisocyanate curing agent is 100:20, and the ratio of the NCO group of the polyisocyanate curing agent to the OH group of the cross-linkable component is 1.25:1.

Furthermore, the aqueous hydroxy acrylic resin dispersion, pigment, dispersant, second solvent, and defoamer are ground to a fineness of less than 10 μm using a sand mill, and then a substrate wetting agent, a rheological additive, an anti-flash rust agent, an ultraviolet light absorber, and a hindered amine light stabilizer are added in sequence under high-speed stirring conditions to obtain the cross-linkable component that is evenly mixed.

During construction, the cross-linkable component and the polyisocyanate curing agent are mixed evenly according to a certain proportion, and diluted with water to a viscosity of 15 to 40 seconds, wherein the viscosity is a coating-4 cup viscosity.

The workability and appearance of the coating formed by the bottom-surface integrated water-based coating composition described in this embodiment are shown in Table 1 and Table 2. The evaluation method for bubble burst is as follows: the bottom-surface integrated water-based coating composition described in this embodiment is sprayed with a Sata JET5000 upper pot gun (1.8 mm diameter), the flash-drying time between spraying passes is 1 minute, the leveling time is 15 minutes, the leveling time is 15 minutes, and then placed in a 60-degree oven for 40 minutes.

Example 2

In this embodiment, a bottom-surface integrated water-based coating composition is provided, the water-based coating composition comprising: a cross-linkable component and a polyisocyanate curing agent;

The cross-linkable component is composed of the following components in terms of mass percentage:

The first solvent of the polyisocyanate curing agent is propylene glycol methyl ether acetate (PMA).

The aqueous hydroxy acrylic resin dispersion is obtained by free radical copolymerization of acrylate monomers and vinyl monomers to obtain a polymer with uniform molecular weight distribution and active groups in the chain segments that can participate in curing and crosslinking. The polymer is further neutralized and emulsified to obtain an aqueous hydroxy acrylic resin dispersion with low solvent content, high solid content, and a core-shell structure. Based on the solid component, the hydroxyl value of the aqueous hydroxy acrylic resin dispersion is 100-130 mgKOH/g, the pH value is 6.5-8.5, the particle size is 100-200nm, the solid acid value is 18-25 mgKOH/g, and the number average molecular weight is about 5000-10000. This resin is a self-produced resin of Nippon Paint (China) Co., Ltd.

The coloring pigment is 19.0 parts of TI-PURE R-960 titanium dioxide and 1.0 parts of MITSUBISHI CARBON BLACKMA-100 carbon black. The anti-rust pigment is 4.0 parts of Nubirox 302 and 4.0 parts of Nubirox 106. The filler is 5.0 parts of precipitated barium sulfate and 3.0 parts of matting powder SYLYSIA 350. The dispersant is Additol VXW 6208. The second solvent is 3.0 parts of dipropylene glycol monobutyl ether, 1.0 parts of ethylene glycol butadiene and 2.0 parts of alkane 120# solvent oil. The defoamer is 0.5 parts of TEGO Foamex 815 defoamer and 0.5 parts of SURFYNOL 104BC defoamer. The substrate wetting agent is BYK 346. The rheological additive is 0.5 parts of ACRTSOL RM-998W and 0.5 parts of ACRTSOL RM-3030NPR. The flash rust inhibitor is FlashProTAC F2M. The ultraviolet light absorber and hindered amine light stabilizer are EVERSORB AQ1 and TINUVIN292 respectively.

The mass solid content of the polyisocyanate curing agent is 68wt%, and the polyisocyanate curing agent is a mixture of hydrophobic Desmodur N 3900 and hydrophilic curing agent Bayhydur 401-60PGDA, with the proportions of the two being 55 parts and 20 parts respectively.

The mass ratio of the cross-linkable component to the polyisocyanate curing agent is 100:15, and the ratio of the NCO group of the polyisocyanate curing agent to the OH group of the cross-linkable component is 1.15:1.

Furthermore, the aqueous hydroxy acrylic resin dispersion, pigment, dispersant, second solvent, and defoamer are ground to a fineness of less than 10 μm using a sand mill, and then a substrate wetting agent, a rheological additive, an anti-flash rust agent, an ultraviolet light absorber, and a hindered amine light stabilizer are added in sequence under high-speed stirring conditions to obtain the cross-linkable component that is evenly mixed.

During construction, the cross-linkable component and the polyisocyanate curing agent are mixed evenly in proportion, and diluted with water to a viscosity of 15-40s, wherein the viscosity is a coating-4 cup viscosity.

The workability and appearance of the coating formed by the bottom-surface integrated water-based coating composition described in this embodiment are shown in Table 1 and Table 2. The evaluation method for bubble burst is as follows: the bottom-surface integrated water-based coating composition described in this embodiment is sprayed with a Sata JET5000 upper pot gun (1.8 mm diameter), the flash-drying time between spraying passes is 1 minute, the leveling time is 15 minutes, the leveling time is 15 minutes, and then placed in a 60-degree oven for 40 minutes.

Example 3

In this embodiment, a bottom-surface integrated water-based coating composition is provided, the water-based coating composition comprising: a cross-linkable component and a polyisocyanate curing agent;

The cross-linkable component is composed of the following components in terms of mass percentage:

The first solvent of the polyisocyanate curing agent is a mixture of propylene glycol diacetate (PGDA) and propylene carbonate, and the mass ratio of the two is 2:1.

The aqueous hydroxy acrylic resin dispersion is a polymer obtained by free radical copolymerization of acrylate monomers and vinyl monomers to obtain a uniform molecular weight distribution and a chain segment with active groups that can participate in curing and crosslinking. The polymer is further neutralized and emulsified to obtain an aqueous hydroxy acrylic resin dispersion with a low solvent content and a high solid content and a core-shell structure. Based on the solid component, the hydroxyl value of the aqueous hydroxy acrylic resin dispersion is 100-130 mgKOH/g, the pH value is 6.5-8.5, the particle size is 100-200 nm, the solid acid value is 18-25 mgKOH/g, and the number average molecular weight is about 5000-10000. This resin is a self-produced resin of Nippon Paint (China) Co., Ltd.

The coloring pigment is 14.0 parts of TI-PURE R-960 titanium dioxide and 1.0 parts of MITSUBISHI CARBON BLACKMA-100 carbon black. The anti-rust pigment is 4.0 parts of 409 zinc phosphate and 2.0 parts of CLF102 aluminum tripolyphosphate. The filler is precipitated barium sulfate. The dispersant is TEGO Dispers 755W. The second solvent is 1.0 parts of dipropylene glycol monobutyl ether, 2.0 parts of ethylene glycol butyl ether and 1.0 parts of alkane 150# solvent oil. The defoamer is 0.5 parts of BYK 024 defoamer and 0.5 parts of SURFYNOL 107L defoamer. The substrate wetting agent is TEGO Twin 4100. The rheological additive is 0.5 parts of ACRTSOLRM-8W and 0.5 parts of ACRTSOL RM-2020NPR. The flash rust inhibitor is Halox 515. The ultraviolet light absorber and the hindered amine light stabilizer are TINUVIN 99DW(N) and TINUVIN 400DW(N) respectively.

The mass solid content of the polyisocyanate curing agent is 60wt%, and the polyisocyanate curing agent is BASONAT HI2000.

The mass ratio of the cross-linkable component to the polyisocyanate curing agent is 100:30, and the ratio of NCO groups to OH groups is 1.6.

Furthermore, the water-based hydroxy acrylic resin dispersion, pigment, dispersant, second solvent, and defoamer are ground to a fineness of less than 10 μm using a sand mill, and then a substrate wetting agent, a rheological additive, an ultraviolet light absorber, and a hindered amine light stabilizer are added in sequence under high-speed stirring conditions to obtain the cross-linkable component that is evenly mixed.

During construction, the cross-linkable component and the polyisocyanate curing agent are mixed evenly according to a certain proportion, and diluted with water to a viscosity of 15 to 40 seconds, wherein the viscosity is a coating-4 cup viscosity.

The workability and appearance of the coating formed by the bottom-surface integrated water-based coating composition described in this embodiment are shown in Table 1 and Table 2. The evaluation method for bubble burst is as follows: the bottom-surface integrated water-based coating composition described in this embodiment is sprayed with a Sata JET5000 upper pot gun (1.8 mm diameter), the flash-drying time between spraying passes is 1 minute, the leveling time is 15 minutes, and then placed in a 60-degree oven for 40 minutes.

Example 4

In this embodiment, a bottom-surface integrated water-based coating composition is provided, the water-based coating composition comprising: a cross-linkable component and a polyisocyanate curing agent;

The cross-linkable component is composed of the following components in terms of mass percentage:

The first solvent of the polyisocyanate curing agent is ethylene carbonate.

The aqueous hydroxy acrylic resin dispersion is a polymer obtained by free radical copolymerization of acrylate monomers and vinyl monomers to obtain a uniform molecular weight distribution and a chain segment with active groups that can participate in curing and crosslinking. The polymer is further neutralized and emulsified to obtain an aqueous hydroxy acrylic resin dispersion with a low solvent content and a high solid content and a core-shell structure. Based on the solid component, the hydroxyl value of the aqueous hydroxy acrylic resin dispersion is 100-130 mgKOH/g, the pH value is 6.5-8.5, the particle size is 100-200 nm, the solid acid value is 18-25 mgKOH/g, and the number average molecular weight is about 5000-10000. This resin is a self-produced resin of Nippon Paint (China) Co., Ltd.

The coloring pigment is 5.0 parts of TI-PURE R-960 titanium dioxide, 5.0 parts of Hostaperm YELLOW H3G-CN pigment, 4.0 parts of iron oxide yellow YZ 1688 and 1.0 parts of Pigment Yellow PY139WI. The anti-rust pigment is 4.0 parts of Nubirox 102 and 2.0 parts of 409 zinc phosphate. The filler is 2.0 parts of feldspar powder PGf-7 and 5.0 parts of barite powder B45. The dispersant is Dispex Ultra PX 4585. The second solvent is 1.0 parts of dipropylene glycol dibutyl ether, 2.0 parts of ethylene glycol butyl ether and 1.0 parts of alkane 200# solvent oil. The defoamer is 0.5 parts of BYK 028 defoamer and 0.5 parts of SURFYNOL 107L defoamer. The substrate wetting agent is DYNOL 360. The rheological additive is 0.5 parts of ACRTSOL RM-12W and 0.5 parts of ACRTSOL RM-3030NPR. The flash rust inhibitor is ASCOTRAN H14. The ultraviolet light absorber and hindered amine light stabilizer are TINUVIN 99DW(N) and EVERSORB 93 respectively.

The mass solid content of the polyisocyanate curing agent is 60wt%, and the polyisocyanate curing agent is Desmodur3300.

The mass ratio of the cross-linkable component to the polyisocyanate curing agent was 100:25, and the ratio of NCO groups to OH groups was 1.3.

Furthermore, the water-based hydroxy acrylic resin dispersion, pigment, dispersant, second solvent, and defoamer are ground to a fineness of less than 10 μm using a sand mill, and then a substrate wetting agent, a rheological additive, an ultraviolet light absorber, and a hindered amine light stabilizer are added in sequence under high-speed stirring conditions to obtain the cross-linkable component that is evenly mixed.

During construction, the cross-linkable component and the polyisocyanate curing agent are mixed evenly according to a certain proportion, and diluted with water to a viscosity of 15 to 40 seconds, wherein the viscosity is a coating-4 cup viscosity.

The workability and appearance of the coating formed by the bottom-surface integrated water-based coating composition described in this embodiment are shown in Table 1 and Table 2. The evaluation method for bubble burst is as follows: the bottom-surface integrated water-based coating composition described in this embodiment is sprayed with a Sata JET5000 upper pot gun (1.8 mm diameter), the flash-drying time between spraying passes is 1 minute, the leveling time is 15 minutes, and then placed in a 60-degree oven for 40 minutes.

Example 5

In this embodiment, a bottom-surface integrated water-based coating composition is provided, the water-based coating composition comprising: a cross-linkable component and a polyisocyanate curing agent;

The cross-linkable component is composed of the following components in terms of mass percentage:

The first solvent of the polyisocyanate curing agent is a mixture of propylene glycol diacetate (PGDA) and propylene carbonate, and the mass ratio of the two is 2/1.

6511与烟台万华化学集团股份有限公司的Antkote 2035混合物，三者的质量比例为2:1:1。The aqueous hydroxylated acrylic resin dispersion is aqueous hydroxylated acrylic resin dispersion A and

A mixture of 6511 and Antkote 2035 of Yantai Wanhua Chemical Group Co., Ltd., with the mass ratio of the three being 2:1:1.

The aqueous hydroxy acrylic resin dispersion A is obtained by free radical copolymerization of acrylate monomers and vinyl monomers to obtain a polymer with uniform molecular weight distribution and active groups in the chain segments that can participate in curing and crosslinking. The polymer is further neutralized and emulsified to obtain an aqueous hydroxy acrylic resin dispersion with low solvent content, high solid content, and a core-shell structure. Based on the solid component, the hydroxyl value of the aqueous hydroxy acrylic resin dispersion is 100-130 mgKOH/g, the pH value is 6.5-8.5, the particle size is 100-200nm, the solid acid value is 18-25 mgKOH/g, and the number average molecular weight is about 5000-10000. This resin is a self-produced resin of Nippon Paint (China) Co., Ltd.

The coloring pigment is 14.0 parts of TI-PURE R-960 titanium dioxide and 1.0 parts of MITSUBISHI CARBON BLACKMA-100 carbon black. The anti-rust pigment is 4.0 parts of 409 zinc phosphate and 2.0 parts of CLF102 aluminum tripolyphosphate. The filler is sub-nano precipitated barium sulfate. The dispersant is Solsperse W400. The second solvent is 1.0 parts of dipropylene glycol monobutyl ether, 2.0 parts of ethylene glycol butyl ether and 1.0 parts of alkane 150# solvent oil. The defoamer is 0.5 parts of BYK 024 defoamer and 0.5 parts of SURFYNOL 107L defoamer. The substrate wetting agent is TEGO Twin 4100. The rheological additive is 0.5 parts of ACRTSOLRM-8W and 0.5 parts of ACRTSOL RM-2020NPR. The flash rust inhibitor is Halox 515. The ultraviolet light absorber and the hindered amine light stabilizer are TINUVIN 99DW(N) and TINUVIN 400DW(N) respectively.

The mass solid content of the polyisocyanate curing agent is 67wt%, and the polyisocyanate curing agent is a mixture of a hydrophobic curing agent Duranate TUL-100 and a hydrophilic curing agent Bayhydur 401-60 PGDA, with the mass parts of the two being 55 parts and 20 parts respectively.

The mass ratio of the cross-linkable component to the polyisocyanate curing agent was 100:25, and the ratio of NCO groups to OH groups was 1.3.

Furthermore, the water-based hydroxy acrylic resin dispersion, pigment, dispersant, second solvent, and defoamer are ground to a fineness of less than 10 μm using a sand mill, and then a substrate wetting agent, a rheological additive, an ultraviolet light absorber, and a hindered amine light stabilizer are added in sequence under high-speed stirring conditions to obtain the cross-linkable component that is evenly mixed.

During construction, the cross-linkable component and the polyisocyanate curing agent are mixed evenly according to a certain proportion, and diluted with water to a viscosity of 15 to 40 seconds, wherein the viscosity is a coating-4 cup viscosity.

The workability and appearance of the coating formed by the bottom-surface integrated water-based coating composition described in this embodiment are shown in Table 1 and Table 2. The evaluation method for bubble burst is as follows: the bottom-surface integrated water-based coating composition described in this embodiment is sprayed with a Sata JET5000 upper pot gun (1.8 mm diameter), the flash-drying time between spraying passes is 1 minute, the leveling time is 15 minutes, and then placed in a 60-degree oven for 40 minutes.

Example 6

In this embodiment, a bottom-surface integrated water-based coating composition is provided, the water-based coating composition comprising: a cross-linkable component and a polyisocyanate curing agent;

The cross-linkable component is composed of the following components in terms of mass percentage:

The first solvent of the polyisocyanate curing agent is a mixture of propylene glycol diacetate (PGDA) and propylene carbonate, and the mass ratio of the two is 2:1.

6515与烟台万华化学集团股份有限公司的Antkote 2036混合物，二者的质量比例为2:1。所述着色颜料为14.0份TI-PURE R-960钛白粉和1.0份MITSUBISHI CARBON BLACK MA-100炭黑。The aqueous hydroxy acrylic resin dispersion is

The mixture of 6515 and Antkote 2036 of Yantai Wanhua Chemical Group Co., Ltd., the mass ratio of the two is 2: 1. The coloring pigment is 14.0 parts of TI-PURE R-960 titanium dioxide and 1.0 parts of MITSUBISHI CARBON BLACK MA-100 carbon black.

The anti-rust pigment is 4.0 parts of 409 zinc phosphate and 2.0 parts of CLF102 aluminum tripolyphosphate. The filler is sub-nano precipitated barium sulfate. The dispersant is Solsperse W400. The second solvent is 1.0 parts of dipropylene glycol monobutyl ether, 2.0 parts of ethylene glycol butyl ether and 1.0 parts of alkane 150# solvent oil. The defoamer is 0.5 parts of BYK 024 defoamer and 0.5 parts of SURFYNOL 107L defoamer. The substrate wetting agent is TEGO Twin 4100. The rheological additive is 0.5 parts of ACRTSOLRM-8W and 0.5 parts of ACRTSOL RM-2020NPR. The flash rust inhibitor is Halox 515. The ultraviolet light absorber and the hindered amine light stabilizer are TINUVIN 99DW(N) and TINUVIN 400DW(N) respectively.

The mass solid content of the polyisocyanate curing agent is 67wt%, and the polyisocyanate curing agent is a mixture of a hydrophobic curing agent Duranate TUL-100 and a hydrophilic curing agent Bayhydur 401-60PGDA, with the mass parts of the two being 55 parts and 20 parts respectively.

The mass ratio of the cross-linkable component to the polyisocyanate curing agent was 100:30, and the ratio of NCO groups to OH groups was 1.4.

Furthermore, the water-based hydroxy acrylic resin dispersion, pigment, dispersant, second solvent, and defoamer are ground to a fineness of less than 10 μm using a sand mill, and then a substrate wetting agent, a rheological additive, an ultraviolet light absorber, and a hindered amine light stabilizer are added in sequence under high-speed stirring conditions to obtain the cross-linkable component that is evenly mixed.

During construction, the cross-linkable component and the polyisocyanate curing agent are mixed evenly according to a certain proportion, and diluted with water to a viscosity of 15 to 40 seconds, wherein the viscosity is a coating-4 cup viscosity.

The workability and appearance of the coating formed by the bottom-surface integrated water-based coating composition described in this embodiment are shown in Table 1 and Table 2. The evaluation method for bubble burst is as follows: the bottom-surface integrated water-based coating composition described in this embodiment is sprayed with a Sata JET5000 upper pot gun (1.8 mm diameter), the flash-drying time between spraying passes is 1 minute, the leveling time is 15 minutes, and then placed in a 60-degree oven for 40 minutes.

Comparative Example 1

Example 1 was repeated. The difference between this comparative example 1 and Example 1 is that in the cross-linkable component, the hydroxy acrylic resin is Antkote 2042 resin produced by Yantai Wanhua Chemical Group Co., Ltd.; the other conditions remain unchanged, and the test is performed according to the method of the above embodiment. The Antkote 2042 resin is also the resin used in currently commercially available products.

Comparative Example 2

Example 1 was repeated. The difference between this comparative example 2 and Example 1 is that the polyisocyanate curing agent is BURNOCK DNW-5500, an isocyanate curing agent for water-based resins produced by DIC Synthetic Resins (Zhongshan) Co., Ltd., and the other conditions remain unchanged, and the test is carried out according to the method of the above example. This isocyanate curing agent is also a polyisocyanate curing agent used in currently commercially available products.

In the above embodiments and comparative examples of the present invention, the construction properties are mainly compared under high temperature conditions, mainly focusing on high temperature and high humidity (35°C/75%) and high temperature and low humidity (35°C/30%) conditions. The construction properties are shown in Table 1.

Table 1. Applicability of coatings of Examples 1 to 6 and Comparative Examples 1 to 2

It can be seen from the experimental results in Table 1 that, compared with the currently commercially available samples for preparing water-based two-component polyurethane bottom-and-top integrated coatings (Comparative Examples 1 and 2), the bottom-and-top integrated water-based coating composition provided in the embodiments of the present application has a high bubble burst film thickness and good anti-sagging properties under high temperature and low humidity and high temperature and high humidity conditions. At the same time, compared with Comparative Sample 2, the bottom-and-top integrated water-based coating composition provided in the embodiments of the present application has a high sagging film thickness, i.e., a strong anti-sagging property, under high humidity conditions.

Studies have shown that the high bubble film thickness of the bottom-and-top integrated water-based coating composition provided in the embodiment of the present application is related to the selected water-based hydroxy acrylic resin dispersion and hydrophobic polyisocyanate curing agent, and the high anti-sagging property is related to the high solid content of the construction caused by the selected hydrophobic polyisocyanate curing agent. It can be seen that the bottom-and-top integrated water-based coating composition provided in the present application has good construction properties.

Furthermore, the test performance substrate used was an SPCC steel plate, which was then coated with the water-based coating composition, surface dried for 30 minutes, baked at 80°C for 2 hours, and placed at room temperature for 7 days before testing the performance. The performance is shown in Table 2.

Table 2. Properties of the coatings of Examples 1 to 6 and Comparative Examples 1 to 2

As shown in Table 2, relative to the currently commercially available polyurethane coating samples (Comparative Example 1 and Comparative Example 2), the coating formed by the bottom-surface integrated aqueous coating composition provided in the embodiment of the present application has good water resistance and acid and alkali resistance, and a high-gloss coating can also be prepared. This is mainly due to the fact that the hydrophobic polyisocyanate curing agent and the aqueous hydroxy acrylic dispersion form a three-dimensional network cross-linked structure through chemical crosslinking. At the same time, compared with Comparative Example 1 and Comparative Example 2, the aqueous polyurethane bottom-surface integrated coating provided by the present application has good weather resistance and corrosion resistance, which is mainly due to the fact that the aqueous hydroxy acrylic resin dispersion described in the present application is related to the hydrophobic polyisocyanate curing agent.

It can also be seen from Table 1 and Table 2 that the bottom-surface integrated water-based coating composition described in the present application and the coating formed therefrom have a wide range of construction applications. The coating having a three-dimensional cross-linked network structure obtained after baking has not only good salt spray resistance and water resistance, but also excellent surface effect and high weather resistance, and is suitable for various industries such as locomotives, machinery and equipment, steel structures and wooden furniture.

The present application has been described by the above-mentioned relevant embodiments, but the above-mentioned embodiments are only examples for implementing the present application. It must be pointed out that the disclosed embodiments do not limit the scope of the present application. On the contrary, modifications and equivalent settings contained in the spirit and scope of the claims are included in the scope of the present application.

Claims (10)

1. A bottom-to-top integrated water-based coating composition, characterized in that the water-based coating composition comprises: a cross-linkable component and a polyisocyanate curing agent, wherein: The crosslinkable component comprises an aqueous hydroxy acrylic resin dispersion, The polyisocyanate curing agent comprises a hydrophobic polyisocyanate, and The ratio of the NCO group of the polyisocyanate curing agent to the OH group of the crosslinkable component is (1-1.6):1. 2. The water-based coating composition according to claim 1, wherein the mass ratio of the cross-linkable component to the polyisocyanate curing agent is 100:(15-30). 3. The water-based coating composition according to claim 1, characterized in that, based on 100 parts by total mass of the cross-linkable component, the cross-linkable component comprises 40-70 parts by mass of the water-based hydroxy acrylic resin dispersion. 4. The aqueous coating composition according to any one of claims 1 to 3, characterized in that the polyisocyanate curing agent further comprises a hydrophilic polyisocyanate, and the mass ratio of the hydrophobic polyisocyanate to the hydrophilic isocyanate is (2.5-2.75):1. 5. The water-based coating composition according to any one of claims 1 to 4, characterized in that the polyisocyanate curing agent further comprises a first solvent, and the mass solid content of the polyisocyanate curing agent is 50-70%. 6. The water-based coating composition according to any one of claims 1 to 5, characterized in that the cross-linkable component further comprises an anti-rust pigment and a coloring pigment, wherein the anti-rust pigment is selected from at least one of composite iron-titanium powder, composite molybdenum-titanium powder, composite hybrid phosphate anti-rust pigment and composite molybdate anti-rust pigment; and the coloring pigment is selected from at least one of titanium dioxide, carbon black, yellow iron oxide, black iron oxide, phthalocyanine blue, organic red, organic yellow and organic orange. 7. The aqueous coating composition according to claim 6, wherein the crosslinkable component further comprises a filler, wherein the filler is selected from at least one of talc powder, feldspar powder, barite powder, precipitated barium sulfate and mica powder. 8. The aqueous coating composition according to any one of claims 1 to 5, characterized in that the crosslinkable component further comprises a second solvent, and the second solvent is selected from at least one of ethylene glycol butyl ether, diethylene glycol butyl ether, diethylene glycol ethyl ether acetate, diethylene glycol hexyl ether, diethylene glycol diethyl ether, propylene glycol diacetate, diethylene glycol dibutyl ether, dipropylene glycol dimethyl ether, dipropylene glycol monobutyl ether, tripropylene glycol monobutyl ether solvents and alkane solvent oils. 9. The aqueous coating composition according to any one of claims 1 to 5, characterized in that the crosslinkable component further comprises an auxiliary agent, which is selected from at least one of a dispersant, a defoamer, a substrate wetting agent, a rheological additive, an anti-flash rust agent, a UV absorber and a hindered amine light stabilizer. 10. A coating system comprising a coating layer formed from the aqueous coating composition according to any one of claims 1 to 9.