CN115975484A

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

Info

Publication number: CN115975484A
Application number: CN202111198611.8A
Authority: CN
Inventors: 王雪三; 曾宇; 闪国峰; 胡世明; 李国军; 魏明亮
Original assignee: Nippon Shanghai Coating Research And Development Co ltd; Nippon Paint Industrial Coatings Shanghai Co ltd
Current assignee: Nippon Shanghai Coating Research And Development Co ltd; Nippon Paint Industrial Coatings Shanghai Co ltd
Priority date: 2021-10-14
Filing date: 2021-10-14
Publication date: 2023-04-18

Abstract

The present application relates to a primer-surfaced waterborne coating composition comprising: a crosslinkable component comprising an aqueous hydroxyacrylic resin dispersion and a polyisocyanate curing agent comprising a hydrophobic polyisocyanate, and the ratio of NCO groups of the polyisocyanate curing agent to OH groups of the crosslinkable component being (1-1.6): 1. The method can effectively adjust the chemical reaction speed and the crosslinking density of the waterborne polyurethane primer-topcoat coating. In addition, the foam in the production and construction process can be effectively removed, and the problem of foam explosion is avoided. In addition, the salt spray resistance of the coating formed by the water-based paint composition is improved through reasonable matching of the antirust pigment, the coloring pigment and the filler. The application also relates to a coating system formed from the aqueous coating composition and the use of the aqueous coating composition or coating system in the exterior coating of a product.

Description

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

Technical Field

The application relates to the field of coatings, in particular to a primer-topcoat water-based coating composition, a coating system formed by the water-based coating composition and application of the water-based coating composition or the coating system in product exterior coating.

Background

Corrosion of metals is the phenomenon in which metals are destroyed by the chemical or electrochemical action of the surrounding medium. The corrosion of metal is spread in various fields of national economy, and great loss is brought to the national economy. The losses to mankind due to corrosion are dramatic, with economic losses due to corrosion amounting to about $ 10000 billion per year worldwide, accounting for about 10% of the total metal value worldwide. In 2008, the economic loss caused by corrosion in China is as high as 1.2 trillion to 2 trillion yuan, so that the vigorous development of an anticorrosion technology becomes a necessary scheme for reducing the anticorrosion loss and promoting the transformation of a resource-saving society. The application of corrosion resistant coatings to metal surfaces is one of the most effective and commonly used methods in the protection of metal surfaces. The anticorrosive coating can mainly isolate corrosive medium and metal matrix to reach the anticorrosive purpose.

The double-component polyurethane coating is a three-dimensional network structure formed by crosslinking of hydroxyl acrylic resin and an isocyanate curing agent. The unique structure of polyurethane molecule has the characteristics of soft-hard microphase. The polyurethane molecular chain contains strong polar carbamate group, has high cohesive energy, and can form hydrogen bond between molecular chains to form a hard segment micro-phase region. The polyurethane molecular chain also has good soft chain segments, and is easy to aggregate to form a soft phase region. The polyurethane has the unique 'hard-soft' microphase structural characteristic, so that the coating has good adhesive force, appearance, chemical resistance and hardness, and excellent wear resistance and weather resistance.

Compared with the traditional oily system, the water-based coating composition with the integrated bottom surface obviously reduces VOC (volatile organic compounds) emitted to the air in the processes of manufacturing, constructing, drying, curing and film forming, and reduces pollution and threat to the ecological environment of human beings. The polyisocyanate curing agent reacts with water to release carbon dioxide gas, so that the high-film-thickness spraying of the waterborne polyurethane is prone to generate miliaria in the construction process. The existence of the explosion has obvious negative effects on the salt fog resistance, water resistance, chemical resistance and the like of a paint film, and the quality of a final product is seriously influenced.

Although the primer-surfaced waterborne coating composition has good properties of weather resistance, appearance, chemical resistance and the like, the corrosion resistance is not as good as possible. The most effective solution at present is that the water-based epoxy primer coating is matched with the water-based paint composition with the integrated bottom surface to enhance the corrosion resistance, and the matched corrosion resistance can be widely applied to the fields of steel structures, commercial vehicles, engineering machinery, rail transit and the like. In the early period, the company issued related waterborne polyurethane patents (CN 107629652A and CN 111019504A), but the patent only uses polyurethane as a finish paint and does not have anticorrosion performance, or the anticorrosion performance of the polyurethane finish paint is improved by matching an epoxy primer. However, the scheme requires two types of coatings, namely epoxy and polyurethane, for construction, the construction process is complex, and different construction equipment is required.

In view of the above, it is desirable to provide a novel aqueous coating composition and a coating system to solve the above problems of complicated construction and poor salt spray resistance, water resistance, chemical resistance and the like of the formed paint film.

Disclosure of Invention

The application aims to provide a primer-topcoat water-based paint composition and a coating system formed by the water-based paint composition, so as to solve the problems of high thick film and easy explosion in construction application, poor corrosion resistance and poor appearance effect in performance of a water-based polyurethane coating.

In order to achieve the above objects, according to one aspect of the present application, there is provided an all-in-one aqueous coating composition comprising: a crosslinkable 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 NCO groups of the polyisocyanate curing agent to OH groups of the crosslinkable component is (1-1.6): 1.

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

In some embodiments, the aqueous hydroxyacrylic resin dispersion is included in the crosslinkable component in an amount of 40 to 70 parts by mass, based on 100 parts by mass of the total crosslinkable component.

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

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

In some preferred embodiments, the aqueous hydroxy acrylic resin dispersion comprises an aqueous hydroxy acrylic resin a, the aqueous hydroxy acrylic resin a is obtained by radical copolymerization of acrylate monomers and vinyl monomers to obtain a polymer with uniform molecular weight distribution and active groups capable of participating in curing and crosslinking in a chain segment, and the polymer is further emulsified to obtain the aqueous hydroxy acrylic resin a with a core-shell structure, wherein the resin is a resin produced by libanor paint (china) ltd.

In some preferred embodiments, the aqueous hydroxyacrylic resin dispersion may further comprise an aqueous hydroxyacrylic resin B. The water-based hydroxyl acrylic resin B is one or a mixture of a plurality of commercially available water-based hydroxyl acrylic resins, so as to be mixed with the water-based hydroxyl acrylic resin A to obtain the water-based hydroxyl acrylic resin dispersoid, and the water-based hydroxyl acrylic resin dispersoid meets the hydroxyl value, the pH value, the acid value, the number average molecular weight and the particle size.

The aqueous hydroxyacrylic resin B is exemplified by, but not limited to: the type of the Kossi wound Polymer (China) GmbH is Bayhydrol A2601, bayhydrol A145 or Bayhydrol A2542 waterborne hydroxy acrylic resin, zhan New resin (China) GmbH

6511 or->

6515 or one or more of Antkote 2036, antkote 2035, or Antkote 2042.

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 asymmetric hexamethylene diisocyanate trimer (HDI).

Such as, but not limited to: one or more of products of Duranate TLA100, duranate TUL-100 or Duranate TPA-100 of Asahi Kasei corporation, products of Desmodur N3900, desmodur N3600 or Desmodur 3300 of Kassikawa Limited, products of Wanhua chemical group Inc. of Wannate HT-100 or Wannate HT-600, products of Bassat HI 100, bassat HI 190 or Bassat HI 2000 of Bassfur (China) Limited, or products of Coronate MPAX-75 or Coronate 2796 of Japan Tokyo corporation.

In some embodiments, the polyisocyanate curing agent further comprises a hydrophilic polyisocyanate, and the mass part 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 a ionone diisocyanate.

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

Such as, but not limited to: one or more of Bayhydur aqueous PU curing agent series products (e.g., bayhydur 401-60PGDA or Bayhydur 401-70 PGDA) from Corsia corporation, tolonate IDT 70B aliphatic polyisocyanate (IPDI homopolymer) from Boston group, or OS-9402 aqueous curing agent from Guangzhou New Material science and technology Co., ltd, hydrophilic aliphatic polyisocyanate based on isophorone diisocyanate (IPDI).

In the present application, by screening the aqueous hydroxyl acrylic resin and the polyisocyanate curing agent contained in the above specific aqueous hydroxyl acrylic resin dispersion, the problem of the mixing compatibility of the crosslinkable component and the polyisocyanate curing agent can be effectively solved, and a primer-topcoat one-in-one aqueous coating composition having good application properties and excellent performance can be obtained.

In some embodiments, the polyisocyanate curing agent further comprises a first solvent, and the mass solids content of the polyisocyanate curing agent is 50 to 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 more of butyl acetate, ethyl acetate, propylene glycol methyl ether acetate (PMA), propylene Glycol Diacetate (PGDA), dibasic ester, dipropylene glycol dimethyl ether (DMM) or a carbonate ester solvent; the ketone solvent is one or a mixture of several of methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone or methoxy hexanone; the aromatic solvent is one or a mixture of toluene and xylene.

Such as, but not limited to: DOWANOL PMA, DOWANOL PGDA or PROGLYDETM DMM of Dow chemical (China) Co., ltd.), dibasic ester DBE of England management (Shanghai) Co., or propylene carbonate or alkane solvent oil of Dongyngjin super chemical Co., ltd.

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

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

In some embodiments, the sum of the parts by mass of the rust-preventive pigment, the coloring pigment and the filler contained in the crosslinkable component is 10 to 40, based on 100 parts by mass of the total crosslinkable component.

In some embodiments, the crosslinkable component further comprises a second solvent selected from at least one of ethylene 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 paraffinic mineral spirits. Wherein, the alkane solvent oil is one or a mixture of 100#, 120#, 150#, and 200# solvent oil.

In some embodiments, the crosslinkable component includes 3 to 10 parts by mass of the second solvent, based on 100 parts by mass of the total crosslinkable component.

In some embodiments, the crosslinkable component further comprises an adjuvant selected from at least one of a dispersant, a defoamer, a substrate wetting agent, a rheology adjuvant, a flash rust inhibitor, an ultraviolet light absorber, and a hindered amine light stabilizer.

In some embodiments, the crosslinkable component includes 4 to 14 parts by mass of the coagent, based on 100 parts by mass of the total crosslinkable component.

In some embodiments, the crosslinkable component comprises the adjuvant including the following components, based on 100 parts by mass of the crosslinkable component:

in the application, the foam generated in the production and construction processes can be further effectively removed by matching and using the components in the auxiliary agent in the specific proportion range, and the problem of explosion of the coating in the construction process is avoided.

Such as, but not limited to: the series products of the winning industry group are TEGO Dispers 755W or TEGO Dispers 757W, the series products of Pasteur (China) Limited company are Dispex Ultra PA 4560, dispex Ultra PX 4585 or Dispex Ultra PX 4575, the series products of Picker company are DISPRBYK-2061, DISPRBYK-2055, DISPERBYK-191 or DISPERBYK-2010, or the series products of Luobo-Wen (Shanghai) Limited company are Solsperse W100 and Solsperse W400, or the mixture of one or more of them.

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

Such as, but not limited to: the type of the winning industry group is one or a mixture of more of TEGO Airex 902W, TEGO Foamex 810, TEGO Foamex 815N or TEGO Foamex 825, or BYK 024 or BYK 028. Such acetylenic diol antifoaming agents are exemplified by, but not limited to: the type of the winning industry group is one or more of SURFYNOL AD01, SURFYNOL 104BC, SURFYNOL 420, SURFYNOL 107L or SURFYNOL 440.

In some embodiments, the substrate wetting agent is an organomodified siloxane effective to reduce surface tension.

Such as, but not limited to: BYK 345, BYK 346 or BYK349 products from Bick company, or TEGO Wet 240, TEGO Twin 4100, TEGO Wet 270, DYNOL 360 products from winning industry group.

In some embodiments, the rheology additive is a nonionic polyurethane associative thickener effective to adjust low shear and high shear viscosities. The nonionic polyurethane associative thickener is obtained by nonionic hydrophobic modification. In the application, the rheological additive can effectively adjust the low shear viscosity and the high shear viscosity in the construction process, and can improve the rheological behavior in the construction process.

Such as, but not limited to: the product of the Dow chemical (China) company Limited is ACRYSOL RM-998, ACRYSOL RM-8W, ACRTSOL RM-2020NPR or ACRYSOL RM-12W, or the product of the Hamming new materials science and technology company Limited is DeuRheo WT-105A, RHEOLATE D, deuRheo WT-108F, RHEOLATE or the mixture of a plurality of products.

Such anti-flash rust agents are for example but not limited to: the model of Shanghai CellTab is FlashProTAC F2M, flashProTAC C4E, or Halox 515, halox 350, halox 330 of Shanghai Peng Pan trade Co., ltd, or at least one or more of ASCOTRAN H10, ASCOTRAN H14 of French Ase Ke Di.

The applicant has noted that rapid corrosion and flash rust development can occur as the primer-topcoat one-on-one aqueous coating composition described herein remains wet when applied directly to an iron/steel substrate. However, long-term corrosion inhibitors such as rust-preventive pigments are not suitable for preventing the generation of such flash rust, and thus, in the present application, the flash rust inhibitor in an aqueous solution is used.

Such as, but not limited to: the product of Taiwan Yongoton chemical industry Co., ltd is EVERSORB AQ1 or EVERSORB AQ3, or one or more of TINUVIN 99DW (N), TINUVIN1130 or TINUVIN 123DW (N) of Bassfu (China) Co., ltd.

Such as, but not limited to: the model of Taiwan Yongoto chemical industry Co., ltd is EVERSORB 93, or one or more of the products of Pasteur (China) Co., ltd is TINUVIN 477DW (N), TINUVIN292, TINUVIN 400DW (N) are mixed.

In the application, the ultraviolet absorber and the hindered amine light stabilizer are reasonably matched, so that the coating formed by the primer-topcoat water-based coating composition has good weather resistance.

In a preferred embodiment of the present application, there is provided a one-on-one-top waterborne coating composition comprising: the ratio of NCO groups of the polyisocyanate curing agent to OH groups of the crosslinkable component is (1-1.6) to 1; wherein the content of the first and second substances,

the crosslinkable component comprises the following components in parts by mass based on 100 parts by mass of the crosslinkable component:

based on solid components, the hydroxyl value of the aqueous hydroxyl acrylic resin dispersoid is 100-140 mgKOH/g, the pH value is 6.5-8.5, the acid value is 18-25mgKOH/g, the number average molecular weight is 5000-10000, and the particle diameter is 100-200 nm;

the polyisocyanate curing agent comprises a hydrophobic polyisocyanate which is an aliphatic polyisocyanate based on hexamethylene diisocyanate;

the polyisocyanate curing agent also comprises a first solvent, and the mass solid content of the polyisocyanate curing agent is 50-70%;

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

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

In the above embodiment, the auxiliary agent included in the crosslinkable component includes the following components, based on 100 parts by mass of the crosslinkable component:

in the primer-topcoat aqueous coating composition of the present application, first, by adjusting a specific ratio of the aqueous hydroxyl acrylic resin and the polyisocyanate curing agent in the aqueous hydroxyl acrylic resin dispersion, that is, a specific ratio of NCO groups of the polyisocyanate curing agent to OH groups of the crosslinkable component, a chemical reaction speed and a crosslinking density of the aqueous polyurethane primer-topcoat coating can be effectively adjusted. Secondly, through the specific selection of the water-based hydroxyl acrylic resin contained in the water-based hydroxyl acrylic resin dispersoid and the specific selection of the polyisocyanate curing agent, and the specific proportion of the water-based hydroxyl acrylic resin and the polyisocyanate curing agent, bubbles in the production and construction processes can be effectively removed, and the problem that a coating formed by the primer-topcoat water-based coating composition generates bubbles in the construction process is avoided. Furthermore, the salt spray resistance of the coating formed by the primer-topcoat water-based paint composition is improved through reasonable matching of the antirust pigment, the coloring pigment and the filler.

It will be appreciated by those skilled in the art that the primer-surfaced waterborne coating composition described herein can be used directly for exterior coating of a product without the need for an additional primer layer as a topcoat for the product.

Thus, according to another aspect of the present application, there is also provided a coating system comprising a coating layer formed from the primer-surfaced waterborne coating composition of any one of the above.

Of course, it will be understood by those skilled in the art that the one-coat, water-borne coating composition described herein may also be used for interior finishing of products, as a primer or a midcoat.

Thus, in some embodiments, the coating systems described herein can further include a topcoat-containing layer or a primer layer.

In some embodiments, the one-on-one-top waterborne coating compositions described herein may be matched with a one-part epoxy primer, a two-part epoxy primer, or an acrylic system.

In some embodiments, the primer-surfaced waterborne coating composition described herein forms a coating that is compatible with sandblasted steel panels.

According to another aspect of the present application, there is also provided the use of the above-mentioned primer-surfaced water-based coating composition or the above-mentioned coating system for exterior or interior finishing of a product.

The application provides a primer-topcoat water-based paint composition and a coating formed by the same, and the water-based paint composition and the coating formed by the same have the performance different from that of the conventional paint composition, and have good construction operability and final coating performance by matching the specific actual selection with the specifically described proportion. The primer-topcoat water-based coating composition and the coating formed by the same have wide construction applicability besides simple operation, can maintain high implosion film thickness at normal temperature and high temperature, and are particularly suitable for industrial production under the conditions of high temperature, low humidity, high temperature, high humidity and the like. Meanwhile, the primer-topcoat integrated water-based coating composition forms a coating with a three-dimensional cross-linked network structure after coating and baking, and the coating has good salt mist resistance and water resistance, has excellent apparent effect and high weather resistance, and can be applied to the industrial protection fields of steel structures, commercial vehicles, engineering machinery and the like.

Detailed Description

While the present invention will be described with reference to certain specific embodiments, it will be understood by those skilled in the art that the following descriptions are intended to be illustrative and not limiting, and should not be taken as limiting the scope of the present invention.

Unless otherwise specified, various starting materials for this application are either commercially available or prepared according to conventional methods in the art. Unless otherwise specifically indicated, 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. Any method or material similar to those described can be used in the methods of the present application.

According to one embodiment of the present application, a primer-surfaced waterborne coating composition is provided.

The primer-topcoat water-based paint composition comprises a crosslinkable component and a polyisocyanate curing agent, wherein the crosslinkable component comprises the following components in parts by mass based on 100 parts by mass of the crosslinkable component:

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

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

Therefore, in this embodiment, by screening the appropriate aqueous hydroxyl acrylic resin dispersion and the polyisocyanate curing agent, the problem of the mixing compatibility of the crosslinkable component and the polyisocyanate curing agent can be effectively solved, and a primer-topcoat waterborne coating composition with good construction applicability and excellent performance can be obtained.

In the present embodiment, the pigment includes an antirust pigment and a coloring pigment; the antirust pigment is one or a mixture of a plurality of iron titanium powder, molybdenum titanium powder, phosphate antirust pigment and molybdate antirust pigment; the coloring pigment is one or a mixture of titanium dioxide, carbon black, iron oxide yellow, iron oxide black, phthalocyanine blue, organic red, organic yellow and organic orange. The filler is selected from one or more of talcum 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 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 oil.

In this embodiment, the auxiliary agent included in the crosslinkable component includes, based on 100 parts by mass of the crosslinkable component, the following components:

the specific selection ranges of all components contained in the primer-topcoat waterborne coating composition provided in this embodiment are described in detail in the foregoing, and are not repeated herein.

Example 1

In this embodiment, there is provided a primer-surfaced waterborne coating composition comprising: a crosslinkable component and a polyisocyanate curing agent;

the crosslinkable component comprises the following components in percentage by mass:

the first solvent of the polyisocyanate curing agent is Propylene Glycol Diacetate (PGDA); wherein:

the waterborne hydroxyl acrylic resin dispersoid is a polymer which has uniform molecular weight distribution and active groups on chain segments which can participate in curing and crosslinking and is obtained by the free radical copolymerization of acrylate monomers and vinyl monomers. And further neutralizing and emulsifying the polymer to obtain the aqueous hydroxyl acrylic resin dispersoid which has low solvent content, high solid content and a core-shell structure. Based on solid components, the hydroxyl value of the aqueous hydroxyl acrylic resin dispersoid is 100-130mgKOH/g, the pH value is 6.5-8.5, the particle diameter is 100-200nm, the solid acid value is 18-25mgKOH/g, and the number average molecular weight is about 5000-10000. The resin is a resin produced by Nippon paint (China) Co.

The coloring pigment was 23.0 parts TI-PURE R-960 titanium dioxide and 1.0 part MITSUBISHI CARBON BLACK MA-100 CARBON BLACK. The anti-rust pigment is Nubirox 102. The filler is sub-nanometer 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 part of TEGO Foamex 810 defoamer and 0.5 part of SURFYNOL AD01 defoamer. The substrate wetting agent is BYK 346. The rheological additive is 0.5 part of ACRTSOL RM-8W and 0.5 part of ACRTSOL RM-2020NPR. The flash rust inhibitor 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%, the polyisocyanate curing agent is the mixture of hydrophobic Wannate HT-600 and hydrophilic curing agent Bayhydur 401-60PGDA, and the weight solid content of the polyisocyanate curing agent and the hydrophobic Wannate HT-600 and the hydrophilic curing agent Bayhydur 401-60PGDA are respectively 50 parts and 20 parts.

The mass ratio of the crosslinkable component to the polyisocyanate curing agent is 100.

Further, grinding the water-based hydroxyl acrylic resin dispersoid, the pigment, the dispersing agent, the second solvent and the defoaming agent by a sand mill until the fineness is below 10 mu m, and then sequentially adding the substrate wetting agent, the rheological aid, the flash rust inhibitor, the ultraviolet light absorber and the hindered amine light stabilizer under the condition of high-speed stirring to obtain the uniformly mixed crosslinkable component.

During construction, the crosslinkable component and the polyisocyanate curing agent are uniformly mixed in proportion and diluted to the viscosity of 15-40s by water, wherein the viscosity is coating-4 cup viscosity.

The workability and appearance of the coating formed by the primer-surfaced waterborne coating composition of this example are shown in tables 1 and 2. The evaluation method of the explosion comprises the following steps: the primer-surfaced waterborne coating composition described in this example was sprayed using a Sata JET5000 pot gun (1.8 mm caliber) with a flash dry time of 1 minute between spray lines, a leveling time of 15 minutes, and then placed in a 60 ℃ oven for 40 minutes.

Example 2

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

The waterborne hydroxyl acrylic resin dispersoid is a polymer which has uniform molecular weight distribution and active groups which can participate in curing and crosslinking and are arranged on chain segments, and is obtained by the free radical copolymerization of acrylate monomers and vinyl monomers. And further neutralizing and emulsifying the polymer to obtain the aqueous hydroxyl acrylic resin dispersoid which has low solvent content, high solid content and a core-shell structure. Based on solid components, the hydroxyl value of the aqueous hydroxyl acrylic resin dispersoid is 100-130mgKOH/g, the pH value is 6.5-8.5, the particle diameter is 100-200nm, the solid acid value is 18-25mgKOH/g, and the number average molecular weight is about 5000-10000. The resin is a resin produced by Nippon paint (China) Co.

The color pigment was 19.0 parts TI-PURE R-960 titanium dioxide and 1.0 part MITSUBISHI CARBON BLACK MA-100 CARBON BLACK. The rust-inhibiting 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 part of ethylene glycol butane and 2.0 parts of alkane 120# solvent oil. The defoamer was 0.5 parts TEGO Foamex 815 defoamer with 0.5 parts SURFYNOL 104BC defoamer. The substrate wetting agent is BYK 346. The rheological aid is 0.5 part of ACRTSOL RM-998W and 0.5 part of ACRTSOL RM-3030NPR. The flash rust inhibitor is FlashProTAC F2M. The ultraviolet light absorber and the 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 the mixture of hydrophobic Desmodur N3900 and hydrophilic curing agent Bayhydur 401-60PGDA, wherein the mass solid content of the polyisocyanate curing agent is 55 parts and 20 parts respectively.

During construction, the crosslinkable component and the polyisocyanate curing agent are uniformly mixed in proportion and diluted to the viscosity of 15-40s by water, wherein the viscosity is the viscosity of paint-4 cups.

The workability and appearance of the coating formed by the primer-surfaced waterborne coating composition of this example are shown in tables 1 and 2. The evaluation method of the explosion comprises the following steps: the primer-surfaced waterborne coating composition described in this example was sprayed using a Sata JET5000 pot gun (1.8 mm caliber) with a flash dry time of 1 minute between spray passes, a leveling time of 15 minutes, and then placed in a 60 ℃ oven for 40 minutes.

Example 3

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 Propylene Glycol Diacetate (PGDA) to the propylene carbonate is 2:1.

The color pigment was 14.0 parts TI-PURE R-960 titanium dioxide and 1.0 part MITSUBISHI CARBON BLACK MA-100 CARBON BLACK. The rust-inhibiting pigment is 4.0 parts 409 of zinc phosphate and 2.0 parts CLF102 of aluminum tripolyphosphate. The filler is precipitated barium sulfate. The dispersant is TEGO Dispers 755W. The second solvent is 1.0 part of dipropylene glycol monobutyl ether, 2.0 parts of ethylene glycol monobutyl ether and 1.0 part of alkane type 150# solvent oil. The defoamer was 0.5 part BYK 024 defoamer with 0.5 part SURFYNOL 107L defoamer. The substrate wetting agent is TEGO Twin 4100. The rheological additive is 0.5 part of ACRTSOL RM-8W and 0.5 part 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 HI 2000.

The mass ratio of the crosslinkable component to the polyisocyanate curing agent was 100, and the ratio of nco groups to OH groups was 1.6.

Further, grinding the water-based hydroxyl acrylic resin dispersoid, the pigment, the dispersing agent, the second solvent and the defoaming agent by a sand mill until the fineness is below 10 mu m, and then sequentially adding the substrate wetting agent, the rheological aid, the ultraviolet light absorber and the hindered amine light stabilizer under the condition of high-speed stirring to obtain the cross-linkable component which is uniformly mixed.

During construction, the crosslinkable component and the polyisocyanate curing agent are uniformly mixed in proportion, and diluted to the viscosity of 15-40s by water, wherein the viscosity is coating-4 cup viscosity.

The workability and appearance of the coating formed by the primer-surfaced waterborne coating composition of this example are shown in tables 1 and 2. The evaluation method of the explosion comprises the following steps: the primer-surfaced waterborne coating composition described in this example was sprayed using a Sata JET5000 pot gun (1.8 mm caliber) with a flash dry time of 1 minute between spray passes and a leveling time of 15 minutes, and then placed in a 60 ℃ oven for 40 minutes.

Example 4

In this embodiment, there is provided an all-in-one aqueous coating composition comprising: a crosslinkable component and a polyisocyanate curing agent;

the crosslinkable component comprises the following components in percentage by mass: (ii) a

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

The colored pigments were 5.0 parts TI-PURE R-960 titanium dioxide, 5.0 parts Hostaperm YELLOW H3G-CN Pigment, 4.0 parts iron oxide YELLOW YZ 1688, and 1.0 part Pigment YELLOW PY139WI. The rust-inhibiting 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 part of dipropylene glycol dibutyl ether, 2.0 parts of ethylene glycol butyl ether and 1.0 part of alkane 200# solvent oil. The defoaming agent is 0.5 part of BYK 028 defoaming agent and 0.5 part of SURFYNOL 107L defoaming agent. The substrate wetting agent is DYNOL 360. The rheological additive is 0.5 part of ACRTSOL RM-12W and 0.5 part of ACRTSOL RM-3030NPR. The flash rust inhibitor is ASCOTRAN H14. The ultraviolet light absorber and the 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 mass solid content of the polyisocyanate curing agent is Desmodur 3300.

The mass ratio of the crosslinkable component to the polyisocyanate curing agent was 100, and the ratio of nco groups to OH groups was 1.3.

Further, the water-based hydroxyl acrylic resin dispersoid, the pigment, the dispersing agent, the second solvent and the defoaming agent are ground by a sand mill until the fineness is below 10 mu m, and then the substrate wetting agent, the rheological additive, the ultraviolet light absorber and the hindered amine light stabilizer are sequentially added under the condition of high-speed stirring to obtain the cross-linkable component which is uniformly mixed.

Example 5

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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 propylene glycol diacetate to the propylene carbonate is 2/1.

The aqueous hydroxyacrylic resin dispersionIs a waterborne hydroxyl acrylic resin dispersion A and

6511 and Antkote 2035 of Futaiwanhua chemical group GmbH, in a mass ratio of 2.

The waterborne hydroxyl acrylic resin dispersoid A is a polymer which has uniform molecular weight distribution and active groups which can participate in curing and crosslinking and are arranged on chain segments, and is obtained by the free radical copolymerization of acrylate monomers and vinyl monomers. And further neutralizing and emulsifying the polymer to obtain the aqueous hydroxy acrylic resin dispersoid which has low solvent content, high solid content and a core-shell structure. Based on solid components, the hydroxyl value of the aqueous hydroxyl acrylic resin dispersoid is 100-130mgKOH/g, the pH value is 6.5-8.5, the particle diameter is 100-200nm, the solid acid value is 18-25mgKOH/g, and the number average molecular weight is about 5000-10000. The resin is a resin produced by Nippon paint (China) Co.

The color pigment was 14.0 parts TI-PURE R-960 titanium dioxide and 1.0 part MITSUBISHI CARBON BLACK MA-100 CARBON BLACK. The rust-inhibiting pigment is 4.0 parts of 409 zinc phosphate and 2.0 parts of CLF102 aluminum tripolyphosphate. The filler is sub-nanometer precipitated barium sulfate. The dispersant is Solsperse W400. The second solvent is 1.0 part of dipropylene glycol monobutyl ether, 2.0 parts of ethylene glycol monobutyl ether and 1.0 part of alkane type 150# solvent oil. The defoamer was 0.5 part BYK 024 defoamer with 0.5 part SURFYNOL 107L defoamer. The substrate wetting agent is TEGO Twin 4100. The rheological additive is 0.5 part of ACRTSOL RM-8W and 0.5 part 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%, the polyisocyanate curing agent is a mixture of hydrophobic curing agent Duranate TUL-100 and hydrophilic Bayhydur 401-60PGDA, and the mass parts of the hydrophobic curing agent Duranate TUL-100 and the hydrophilic Bayhydur 401-60PGDA are 55 parts and 20 parts respectively.

Example 6

The aqueous hydroxy acrylic resin dispersion is

6515 and Antkote 2036 from Tantawawa chemical group, inc., in a mass ratio of 2:1. The color pigment was 14.0 parts TI-PURE R-960 titanium dioxide and 1.0 part MITSUBISHI CARBON BLACK MA-100 CARBON BLACK.

The rust-inhibiting pigment is 4.0 parts of 409 zinc phosphate and 2.0 parts of CLF102 aluminum tripolyphosphate. The filler is sub-nanometer precipitated barium sulfate. The dispersant is Solsperse W400. The second solvent is 1.0 part of dipropylene glycol monobutyl ether, 2.0 parts of ethylene glycol monobutyl ether and 1.0 part of alkane type 150# solvent oil. The defoamer was 0.5 part BYK 024 defoamer with 0.5 part SURFYNOL 107L defoamer. The substrate wetting agent is TEGO Twin 4100. The rheological additive is 0.5 part of ACRTSOL RM-8W and 0.5 part 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 ratio of the crosslinkable component to the polyisocyanate curing agent was 100, and the ratio of nco groups to OH groups was 1.4.

The workability and appearance of the coating formed by the primer-surfaced waterborne coating composition of this example are shown in tables 1 and 2. The evaluation method of the explosion comprises the following steps: the primer-surfaced waterborne coating composition described in this example was sprayed using a Sata JET5000 pot gun (1.8 mm caliber) with a flash-off time of 1 minute between spray passes and a leveling time of 15 minutes, and then placed in a 60 ℃ oven for 40 minutes.

Comparative example 1

Example 1 was repeated, and comparative example 1 differs from example 1 in that: in the crosslinkable component, the hydroxy acrylic resin is Antkote 2042 resin of Tantawawa chemical group GmbH; the Antkote 2042 resin, tested as described above in the examples, was also the resin currently used in the commercial product.

Comparative example 2

Example 1 was repeated, and comparative example 2 differs from example 1 in that: the polyisocyanate curing agent was BURNOCK DNW-5500 for aqueous resin manufactured by Diesen synthetic resin (Zhongshan) Co., ltd, and the test was carried out by the method of the above example without changing the other conditions. The isocyanate curing agent is also a polyisocyanate curing agent currently used in commercial products.

In the above examples and comparative examples of the present invention, the results of workability under high temperature and high humidity (35 ℃/75%) and high temperature and low humidity (35 ℃/30%) conditions were as shown in table 1.

TABLE 1 workability of the coatings of examples 1 to 6 and comparative examples 1 to 2

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As can be seen from the experimental results in Table 1, the under-coat one-water coating compositions provided in the examples of the present application have high blister film thickness and good sag resistance under high temperature and low humidity, high temperature and high humidity conditions, compared to the currently commercially available samples (comparative example 1 and comparative example 2) for preparing the aqueous two-component polyurethane under-coat one-coat coating. Meanwhile, the primer-surfaced water-based coating composition provided in the examples of the present application has a high sag film thickness, i.e., a strong sag resistance, under high humidity conditions, relative to comparative sample 2.

It has been found that the primer-topcoat waterborne coating compositions provided in the examples herein have a high burst film thickness associated with the selected waterborne hydroxyacrylic resin dispersion and hydrophobic polyisocyanate curing agent, and a high sag resistance associated with a high build solids content resulting from the selected hydrophobic polyisocyanate curing agent. Therefore, the primer-topcoat water-based coating composition provided by the application has good application property.

Further, the substrate used for testing performance was an SPCC steel plate, which was then coated with the aqueous coating composition, surface-dried for 30 minutes, baked at 80 ℃ for 2 hours, and left to stand at room temperature for 7 days, and the performance was tested as shown in table 2.

TABLE 2 Properties of the coatings of examples 1 to 6 and comparative examples 1 to 2

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As shown in Table 2, compared with the currently commercially available polyurethane coating samples (comparative example 1 and comparative example 2), the primer-topcoat water-based coating composition provided in the examples of the present application forms a coating with good water resistance and acid and alkali resistance, and can also prepare a high-gloss coating. This is mainly due to the fact that the hydrophobic polyisocyanate curing agent forms a three-dimensional network cross-linked structure with the aqueous hydroxyacrylic acid dispersion by chemical cross-linking. Meanwhile, compared with comparative example 1 and comparative example 2, the waterborne polyurethane primer-topcoat coating provided by the application has good weather resistance and corrosion resistance, which is mainly due to the fact that the waterborne hydroxyl acrylic resin dispersion provided by the application is related to the hydrophobic polyisocyanate curing agent.

As can be seen from tables 1 and 2, the primer-topcoat water-based coating composition and the coating formed by the primer-topcoat water-based coating composition have wide construction applicability, and the coating obtained by baking has a three-dimensional cross-linked network structure, has good salt mist resistance and water resistance, has excellent appearance effect and high weather resistance, and is suitable for various industries such as rolling stocks, mechanical equipment, steel structures and wood furniture.

The present application has been described in relation to the above embodiments, which are only examples for implementing the present application. It must be noted that the disclosed embodiments do not limit the scope of the application. Rather, modifications and equivalent arrangements included within the spirit and scope of the claims are included within the scope of the present application.

Claims

1. An all-in-one-top aqueous coating composition, comprising: a crosslinkable component and a polyisocyanate curing agent, wherein,

the crosslinkable component comprises an aqueous hydroxyacrylic resin dispersion,

the polyisocyanate curing agent comprises a 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.

2. The aqueous coating composition of claim 1, wherein the mass ratio of the crosslinkable component to the polyisocyanate curing agent is 100 (15-30).

3. The aqueous coating composition of claim 1, wherein said crosslinkable component comprises 40 to 70 parts by mass of said aqueous hydroxyacrylic resin dispersion, based on 100 parts by mass of the total crosslinkable component.

4. The aqueous coating composition according to any one of claims 1 to 3, wherein the polyisocyanate curing agent further comprises a hydrophilic polyisocyanate, and the ratio of the hydrophobic polyisocyanate to the hydrophilic isocyanate is (2.5-2.75): 1.

5. The aqueous coating composition of any one of claims 1 to 4, wherein the polyisocyanate curing agent further comprises a first solvent, and the polyisocyanate curing agent has a mass solid content of 50 to 70%.

6. The aqueous coating composition of any one of claims 1 to 5, wherein the crosslinkable component further comprises an anticorrosive pigment and a coloring pigment, wherein the anticorrosive pigment is selected from at least one of a complex ferrotitanium powder, a complex molybdatotitanium powder, a complex hybrid phosphate-based anticorrosive pigment, and a complex molybdate-based anticorrosive pigment; the coloring pigment is at least one selected from titanium dioxide, carbon black, iron oxide yellow, iron oxide black, phthalocyanine blue, organic red, organic yellow and organic orange.

7. The aqueous coating composition of claim 6, wherein the crosslinkable component further comprises a filler selected from at least one of talc, feldspar powder, barite powder, precipitated barium sulfate, and mica powder.

8. An aqueous coating composition according to any one of claims 1 to 5 wherein the crosslinkable component further comprises a second solvent selected from at least one of ethylene 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 paraffinic solvent oils.

9. The aqueous coating composition of any one of claims 1 to 5, wherein the crosslinkable component further comprises an adjuvant selected from at least one of dispersants, defoamers, substrate wetting agents, rheology adjuvants, flash rust inhibitors, ultraviolet light absorbers, and hindered amine light stabilizers.

10. A coating system comprising a coating layer formed from the aqueous coating composition of any one of claims 1 to 9.