Water-based single-component coating as well as preparation method and application thereof

Abstract

The invention discloses a water-based single-component coating as well as a preparation method and application thereof, and belongs to the technical field of coatings. The water-based single-component coating provided by the invention is prepared from the following raw materials in parts by mass: 30 to 70 parts of water-based emulsion, 1 to 10 parts of cross-linking agent, 0.5 to 5 parts of dispersing agent, 1 to 20 parts of functional additive, 10 to 50 parts of pigment and filler, 0.001 to 1 part of functional pigment and 2 to 20 parts of water, the water-based emulsion comprises at least one of a water-based acrylic emulsion, a water-based polyurethane modified acrylic emulsion or a water-based polyurethane emulsion; the cross-linking agent is selected from a zirconium cross-linking agent which does not contain ammonium or amine; the dispersing agent comprises an acrylic polymer dispersing agent, a modified acrylic polymer dispersing agent or a combination of the acrylic polymer dispersing agent and the modified acrylic polymer dispersing agent. According to the invention, the zirconium cross-linking agent which does not contain ammonium or amine is adopted, can react with tannic acid permeated from wood or woodware, and can also react with residual carboxyl in a water-based emulsion system to form good cross-linking property, so that the sealing property of a paint film is greatly improved, and the problem of yellowing of the paint film is solved.

Description

Technical Field

[0001] The invention belongs to the technical field of coatings, and in particular relates to a water-based single-component coating and a preparation method and application thereof. Background Art

[0002] With the development of society, people have higher and higher requirements for environmental protection in recent years. Although wood products coated with water-based paints have excellent environmental performance, their performance is often still a certain distance away from oil-based products. Specifically, the sealing property is not good. After coating, the plant tannin (the main component of tannin components that are easily soluble in water is tannic acid, and its color is mainly brown or light yellow) in the wood or furniture seeps out, causing the paint film to turn yellow. The existing technology mainly solves the problem of yellowing of the paint film through the following technical approaches: 1. Adopting a cationic acrylic emulsion system, the positively charged groups react with the tannic acid that seeps out of the wood or wood to achieve the effect of improving the sealing property of the paint film. 2. Adopting an anionic acrylic emulsion system, adding zinc oxide powder (or other metal oxides and additives with the same function), reacting with the tannic acid that seeps out of the wood or wood to form a chelate, thereby increasing the sealing property of the paint film. 3. Adopting a two-component system, component A adopts a hydroxy acrylic emulsion, and component B adopts an isocyanate curing agent. The sealing property of the paint film is improved through multiple curing to avoid the yellowing caused by the seepage of tannic acid in the wood or furniture.

[0003] However, there are still some problems with the above methods. For example: 1. In the cationic acrylic emulsion system, its synthesis process determines that the content of positively charged groups in the system is low, the formed paint film has general compactness and limited sealing performance. At the same time, since a cationic system is used, if the equipment is not thoroughly cleaned, the residual components will react with the subsequent anionic acrylic emulsion system, forming particles, which greatly affects the production efficiency. 2. In the anion system, adding zinc oxide powder (or other metal oxides) reacts with tannic acid in wood or woodware to form metal ion chelates, reducing the penetration of tannic acid into the paint film and resulting in yellowing. However, its metal ion chelates often have colors and can also change the color of the paint film. For example, tannic acid and Fe(III) can form brown chelates under alkaline (pH>7) conditions, blue chelates under weakly acidic (3<pH<6) conditions, and colorless chelates under strongly acidic (pH<2) conditions. Adding zinc oxide powder (or other metal ion oxides) will cause a significant increase in the heavy metal content of the system, not meeting the waterborne woodware standard. At the same time, adding zinc oxide powder to the system easily forms chelates with latex particles, affecting the storage stability. It often shows: becoming coarser, abnormal increase in viscosity, and even gelling. In addition, adding tannic acid inhibitors in the anion system replaces traditional metal oxides while maintaining the ability to react with tannic acid in wood or woodware, reducing the penetration of tannic acid into the paint film and resulting in yellowing. However, the compatibility of the added tannic acid inhibitor with the emulsion system is often poor. Adding less is not enough to react with the dissolved tannic acid, and adding too much will cause: abnormal increase in viscosity, and even gelling. At the same time, its main component is ammonium salt, which has a strong pungent smell and is not conducive to the operator's use. 3. In the two-component system, the hydroxyl acrylic emulsion in the emulsion reacts with the isocyanate curing agent to form a dense paint film. At the same time, the excess curing agent will also react with the hydroxyl groups in water and tannic acid, having good sealing performance. However, its sealing performance is affected by the hydroxyl activity of the emulsion, the addition amount, and the amount of isocyanate curing agent participating in the reaction. The sealing performance will decrease over time, and it is inevitable that there will be residual curing agent components (such as MDI) with biological hazards in the paint film, affecting the safety of the paint film. In addition, the two-component system needs to be prepared and used immediately during construction, which is inconvenient to operate and not conducive to production efficiency.

[0004] At the same time, most of the formulations in the existing technical solutions are designed based on spraying formulations, and the formulations contain a large amount of fillers. When using roller coating construction, the covering power is poor and the adhesion is poor. Summary of the Invention

[0005] In order to overcome at least one of the above problems existing in the prior art, one of the objectives of the present invention is to provide a waterborne one-component coating, which can react with tannic acid permeating from wood or woodware, has good sealing performance, excellent stability, and a simple, safe, and environmentally friendly preparation process.

[0006] Another objective of the present invention is to provide a preparation method for the above waterborne one-component coating.

[0007] A third object of the present invention is to provide an application of the above-mentioned water-based one-component coating.

[0008] In order to achieve the above object, the technical solution adopted by the present invention is:

[0009] The first aspect of the present invention provides a water-based single-component coating, comprising the following raw materials in parts by weight: 30 to 70 parts of an aqueous emulsion, 1 to 10 parts of a cross-linking agent, 0.5 to 5 parts of a dispersant, 1 to 20 parts of a functional additive, 10 to 50 parts of a color filler, 0.001 to 1 part of a functional pigment, and 2 to 20 parts of water; the aqueous emulsion comprises at least one of an aqueous acrylic emulsion, an aqueous polyurethane-modified acrylic emulsion, or an aqueous polyurethane emulsion; the cross-linking agent is selected from a zirconium cross-linking agent that does not contain ammonium or amine; the dispersant comprises an acrylic polymer dispersant, a modified acrylic polymer dispersant, or a combination thereof.

[0010] The water-based single-component coating of the present invention has good cross-linking properties, can react with tannic acid that penetrates from wood or wooden articles, and effectively improve the problem of yellowing of the wood or wooden articles paint film. Among them, the zirconium cross-linking agent that does not contain ammonium or amine can not only react with the tannic acid that penetrates from wood or wooden articles, but also react with the residual carboxyl groups in the aqueous emulsion systems such as aqueous acrylic emulsion, aqueous polyurethane modified acrylic emulsion or aqueous polyurethane emulsion to form good cross-linking properties, greatly improve the sealing property of the paint film, and, since it does not contain ammonium or amine, it does not produce irritating odor; at the same time, the zirconium cross-linking agent of the present invention has good compatibility with other raw materials in the coating, avoiding the problem of high viscosity or even gelation of the coating; in addition, in combination with an acrylic polymer dispersant, it can effectively improve the dispersibility and compatibility of the coating system and improve the storage stability of the coating; combined with color fillers, functional pigments, and functional additives, the comprehensive properties of the coating such as hiding power, dispersibility, storage stability and construction performance are further improved. The coating finally obtained by the present invention can form a paint film with good density, has a sealing effect on various substrates, and has good sealing properties on solid wood substrates such as white oak, red oak, ash, teak, walnut, ash, or other types of wood products. In addition, the coating of the present invention can be directly roller-coated without the need for additional coating of a sealing primer, has high construction efficiency, does not turn yellow in the later stage, has good hiding power, and has strong adhesion.

[0011] Preferably, the zirconium-based cross-linking agent is selected from zirconium carbonate salts.

[0012] The zirconium carbonate salt used in the present invention does not contain ammonium or amine, has good dispersibility and compatibility when used in the present invention, has good coating stability, does not produce irritating odor, and is green and environmentally friendly. More importantly, the zirconium carbonate salt can be cross-linked with the aqueous emulsion of the present invention and can also react with tannic acid in wood or wooden articles, thereby effectively improving the sealing property of the paint film and improving the problem of yellowing of the paint film.

[0013] Preferably, the pH value of the zirconium-based cross-linking agent is 8-10; non-limiting examples include 8.5, 9 or 9.5.

[0014] Preferably, the effective component of the zirconium-based cross-linking agent is ≥ 30 wt %; non-limiting examples include 35 wt %, 40 wt %, 50 wt %, 70 wt % or 90 wt %.

[0015] Preferably, the acid value of the acrylic polymer dispersant is 10 to 20 mgKOH / g; more preferably 12 to 18 mgKOH / g; non-limiting examples include 14 mgKOH / g, 15 mgKOH / g or 16 mgKOH / g.

[0016] Preferably, the modified acrylic polymer dispersant is selected from amine-modified acrylic polymer dispersants.

[0017] Preferably, the amine value of the amine-modified acrylic polymer dispersant is 18 to 30 mgKOH / g; more preferably 20 to 28 mgKOH / g; non-limiting examples include 22 mgKOH / g, 25 mgKOH / g or 27 mgKOH / g.

[0018] Preferably, the aqueous emulsion includes aqueous acrylic emulsion, aqueous polyurethane-modified acrylic emulsion or a combination thereof; further preferably, the aqueous emulsion includes aqueous acrylic emulsion and aqueous polyurethane-modified acrylic emulsion.

[0019] The combination of water-based acrylic emulsion and water-based polyurethane modified acrylic emulsion can provide excellent adhesion and increase the construction tolerance and environmental adaptability of the coating.

[0020] Preferably, the aqueous emulsion comprises Rhechem 6014, Mowipur 1515 or a combination thereof; further preferably, the aqueous emulsion comprises Rhechem 6014 and Mowipur 1515.

[0021] Rhechem 6014 is a water-based acrylic emulsion, and Archroma Mowipur 1515 is a water-based polyurethane-modified acrylic emulsion. The combination of the two can provide better adhesion for the coating and has good compatibility with other raw materials in the coating system, which is conducive to obtaining a coating with good storage stability and good construction performance.

[0022] Preferably, the crosslinking agent is selected from Archroma Mowiplus PC 88.

[0023] Archroma Mowiplus PC 88 is an ammonia-free water-based zirconium crosslinker with an active ingredient of ≥30wt% and a pH value of 8-10. When used in the present invention, it can not only form a good crosslinking effect with the water-based emulsion of the present invention, but also react with tannic acid in wood or wooden articles, thereby effectively improving the sealing property of the paint film and improving the yellowing problem of the paint film. Its ingredients also meet safety and environmental protection standards, and no irritating odor is generated during the reaction process, which is convenient for operators to use.

[0024] Preferably, the dispersant comprises TEGO Dispers 755W, AFCONA 4560 or a combination thereof; further preferably, the dispersant comprises TEGO Dispers 755W and AFCONA 4560.

[0025] TEGO Dispers 755W is a weak anionic polymer high-efficiency wetting and dispersing agent with an acid value of about 15 mgKOH / g; AFCONA 4560 is a modified polyacrylate polymer with an amine value of 20-28 mgKOH / g; the combination of the two can effectively improve the dispersibility and compatibility of the coating system of the present invention and improve the storage stability of the coating of the present invention.

[0026] Preferably, the pigment and filler are selected from titanium dioxide.

[0027] Preferably, the titanium dioxide comprises rutile titanium dioxide produced by the sulfate process, rutile titanium dioxide produced by the chloride process or a combination thereof.

[0028] Preferably, the functional pigment is selected from ultramarine blue powder.

[0029] Color fillers (especially titanium dioxide) and functional pigments (such as ultramarine blue powder) can provide hiding power for the coating of the present invention and adjust the color of the coating. In particular, the addition of ultramarine blue powder in the present invention can effectively eliminate the yellow phase of the paint film and increase the whiteness of the paint film.

[0030] Preferably, the functional additive includes at least one of a pH regulator, a film-forming aid, a defoamer, a wetting agent, a leveling agent or a thickener; further preferably, the functional additive includes a pH regulator, a film-forming aid, a defoamer, a wetting agent, a leveling agent and a thickener.

[0031] Preferably, the pH adjuster is selected from organic amine compounds; more preferably, the pH adjuster is selected from AMP-95.

[0032] The organic amine compound is used as the pH adjuster of the present invention mainly to adjust the pH value of the system and improve the storage stability.

[0033] Preferably, the film-forming aid includes propylene glycol, an alcohol ether compound or a combination thereof; further preferably, the film-forming aid includes at least one of propylene glycol, dipropylene glycol methyl ether (DPM), dipropylene glycol butyl ether (DPNB) or tripropylene glycol butyl ether (TPNB); even more preferably, the film-forming aid includes propylene glycol, dipropylene glycol methyl ether (DPM), dipropylene glycol butyl ether (DPNB) and tripropylene glycol butyl ether (TPNB).

[0034] The use of the above-mentioned film-forming aid in the system of the present invention can achieve better film-forming effect and meet the national VOC requirements and national limit requirements.

[0035] Preferably, the defoaming agent is selected from silicone defoaming agents; further preferably, the silicone defoaming agent includes TEGO AIREX 902W, TEGO FOAMEX 845 or a combination thereof; even more preferably, the silicone defoaming agent includes TEGO AIREX 902W and TEGO FOAMEX 845.

[0036] In the system of the present invention, an organosilicon defoamer, especially the above-mentioned organosilicon defoamer, is used, which has good defoaming stability.

[0037] Preferably, the wetting agent is selected from silicone wetting agents; further preferably, the silicone wetting agent is selected from BYK-3455.

[0038] Preferably, the leveling agent is selected from acrylic leveling agents; further preferably, the acrylic leveling agent is selected from MODAREZ PW 336 produced by Centron.

[0039] The use of acrylic leveling agents, especially the acrylic leveling agents of the above type, in the system of the present invention can effectively improve the fluidity and spreadability of the system.

[0040] Preferably, the thickener includes a polyurethane thickener, a polyether modified thickener or a combination thereof; further preferably, the thickener includes Hemmings RHEOLATE 212, Coatex COAPUR 830W or a combination thereof; further preferably, the thickener includes Hemmings RHEOLATE 212 and Coatex COAPUR 830W.

[0041] Hemmings RHEOLATE 212 is a polyether polyurethane associative rheological additive that can provide high shear viscosity. COAPUR 830W is a solvent-free and alkylphenol polyoxyethylene ether (APEO)-free polyurethane thickener that can effectively improve the viscosity of medium and high shear. The use of the above two thickeners can effectively improve the shear viscosity of the coating of the present invention, making the coating suitable for roller coating construction, and the single paint amount during roller coating is high and the leveling property is good.

[0042] Preferably, the water-based one-component coating comprises the following raw materials in parts by mass: 32 to 65 parts of water-based emulsion, 1.2 to 9 parts of cross-linking agent, 0.8 to 4.5 parts of dispersant, 2 to 15 parts of functional additives, 20 to 45 parts of color fillers, 0.001 to 0.8 parts of functional pigments, and 3 to 18 parts of water.

[0043] Further preferably, the water-based one-component coating comprises the following raw materials in parts by mass: 35 to 60 parts of water-based emulsion, 1.5 to 8 parts of cross-linking agent, 1 to 4 parts of dispersant, 3.15 to 10 parts of functional additives, 25 to 42 parts of color fillers, 0.001 to 0.5 parts of functional pigments, and 4 to 15 parts of water.

[0044] Preferably, the water-based one-component coating comprises the following raw materials in parts by mass: 30 to 70 parts of aqueous emulsion, 1 to 10 parts of cross-linking agent, 0.5 to 5 parts of dispersant, 1 to 7 parts of film-forming aid, 0.01 to 0.3 parts of pH regulator, 0.1 to 0.7 parts of defoaming agent, 0.05 to 0.4 parts of wetting agent, 0.1 to 2 parts of leveling agent, 0.1 to 4 parts of thickener, 10 to 50 parts of color filler, 0.001 to 1 parts of functional pigment, and 2 to 20 parts of water.

[0045] Preferably, the water-based one-component coating comprises the following raw materials in parts by mass: 32 to 65 parts of aqueous emulsion, 1.2 to 9 parts of cross-linking agent, 0.8 to 4.5 parts of dispersant, 1.5 to 6 parts of film-forming aid, 0.03 to 0.25 parts of pH regulator, 0.15 to 0.6 parts of defoamer, 0.08 to 0.35 parts of wetting agent, 0.2 to 1.5 parts of leveling agent, 0.3 to 3.5 parts of thickener, 20 to 45 parts of color filler, 0.001 to 0.8 parts of functional pigment, and 3 to 18 parts of water.

[0046] Further preferably, the water-based one-component coating comprises the following raw materials in parts by mass: 35 to 60 parts of aqueous emulsion, 1.5 to 8 parts of cross-linking agent, 1 to 4 parts of dispersant, 2 to 5 parts of film-forming aid, 0.05 to 0.2 parts of pH regulator, 0.2 to 0.5 parts of defoaming agent, 0.1 to 0.3 parts of wetting agent, 0.3 to 1 parts of leveling agent, 0.5 to 3 parts of thickener, 25 to 42 parts of color filler, 0.001 to 0.5 parts of functional pigment, and 4 to 15 parts of water.

[0047] The second aspect of the present invention provides a method for preparing the water-based one-component coating described in the first aspect of the present invention, comprising the following steps: firstly mixing the dispersant, part of the functional additives and water for a first time, then adding the color filler and the functional pigment for a second time, then adding the water-based emulsion for a third time, and finally adding the crosslinking agent and the remaining functional additives for a fourth time to obtain the water-based one-component coating.

[0048] Preferably, the rotation speed of the first mixing is 700-900 rpm; more preferably, it is 750-850 rpm.

[0049] Preferably, the first mixing time is 2 to 10 minutes; more preferably, it is 4 to 6 minutes.

[0050] Preferably, the second mixing speed is 2000-2400 rpm; more preferably, 2100-2300 rpm.

[0051] Preferably, the second mixing time is 15 to 25 minutes; more preferably, it is 18 to 22 minutes.

[0052] Preferably, the rotation speed of the third mixing is 1000-1400 rpm; more preferably, it is 1100-1300 rpm.

[0053] Preferably, the third mixing time is 2 to 10 minutes; more preferably, it is 4 to 6 minutes.

[0054] Preferably, the fourth mixing speed is 1300-1700 rpm; more preferably, 1400-1600 rpm.

[0055] Preferably, the fourth mixing time is 10 to 20 minutes; more preferably, it is 13 to 17 minutes.

[0056] Preferably, when the functional additives of the raw materials for preparing water-based one-component coatings include at least one of a pH regulator, a film-forming aid, a defoaming agent, a wetting agent, a leveling agent or a thickener, the part of the functional additives added in the first mixing correspondingly include at least one of a pH regulator, a film-forming aid or a defoaming agent, and the remaining functional additives added in the fourth mixing correspondingly include at least one of a wetting agent, a leveling agent or a thickener.

[0057] The third aspect of the present invention provides a use of the water-based one-component coating according to the first aspect of the present invention in preparing a water-based wood coating.

[0058] Preferably, the wood includes at least one of white oak, red oak, ash, teak, walnut or ash.

[0059] The beneficial effects of the present invention are as follows: the present invention adopts a zirconium cross-linking agent that does not contain ammonium or amine, which can not only react with tannic acid that penetrates from wood or wooden articles, but also react with residual carboxyl groups in aqueous emulsion systems such as aqueous acrylic emulsion, aqueous polyurethane-modified acrylic emulsion or aqueous polyurethane emulsion to form good cross-linking, thereby greatly improving the sealing property of the paint film and improving the problem of yellowing of the paint film; in addition, in combination with acrylic polymer dispersants, color fillers, functional pigments, and functional additives, the comprehensive properties of the coating system such as dispersibility, compatibility, impact resistance, hiding power, storage stability and construction performance can be further improved.

[0060] Specifically, compared with the prior art, the present invention has the following advantages:

[0061] 1. The coating of the present invention can form a paint film with good density and has a sealing effect on various substrates. It has good sealing properties on solid wood substrates such as white oak, red oak, ash, teak, round bean wood, ash, or other types of wood products. In addition, the coating of the present invention can be directly roller-coated without the need for additional coating of a sealing primer. The construction efficiency is high, the paint film does not turn yellow in the later stage, and has good hiding power and strong adhesion.

[0062] 2. The coating of the present invention has the characteristics of good adhesion, good impact resistance, fast drying speed, etc. The construction method can be manual roller coating or equipment roller coating, which can be used for factory coating and DIY coating. In addition, the paint film of the present invention has a high solid content, a high coating amount in a single roller coating, a high hiding power, can reduce the number of construction times, and a fast drying time of the paint film. During roller coating construction, continuous production can be carried out, and packaging can be carried out after the production line is off, thereby improving construction efficiency. The production cost of the present invention is low, and a good construction effect can be obtained with a small number of coatings, which can greatly reduce the construction cost. DETAILED DESCRIPTION

[0063] The content of the present invention is further described in detail below through specific examples. It should also be understood that the following examples are only used to further illustrate the present invention and cannot be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the principles set forth in the present invention all belong to the scope of protection of the present invention. The specific process parameters and the like in the following examples are also only examples within a suitable range, that is, those skilled in the art can make a selection within a suitable range through the description herein, and are not limited to the specific data exemplified below. The raw materials, reagents or devices used in the following examples and comparative examples, unless otherwise specified, can all be obtained from conventional commercial sources, or can be obtained by existing known methods.

[0064] Example 1

[0065] A water-based one-component coating, the specific preparation raw materials and amounts are shown in Table 1.

[0066] The water-based one-component coating of this example includes the following preparation steps:

[0067] 1) Take a clean large vat (a), accurately add 2.5g pure water, 0.5g film-forming aid (model commercially available propylene glycol), 2g film-forming aid (model commercially available DPM), 1g film-forming aid (model commercially available DPNB), 1g film-forming aid (model commercially available TPNB), select a suitable dispersion disk, the ratio of the diameter of the dispersion disk to the diameter of the container is about 0.4-0.6, start stirring at 800rpm, aim at the center of the dispersion disk and add 0.05g pH adjuster (model commercially available AMP-95), 1.6g dispersant (model 755W), 1.1g dispersant (model Afcona4560), 0.2g defoamer (model TEGO AIREX 902W), 0.2g defoamer (model TEGOFOAMEX 845) in a thin stream, and stir for 5 minutes.

[0068] 2) Keep stirring speed constant, slowly add 39g titanium dioxide (model BLR-895) and 0.01g ultramarine powder (model FERRO ultramarine blue EP-19) in turn. The feeding speed should be such that the powder does not accumulate on the liquid surface. Wash the excess powder on the edge with 1.5g pure water (manually scrape the cylinder if necessary). After washing, increase the speed to 2200rpm and disperse for 20min until the test fineness is ≤30μm.

[0069] 3) Prepare another clean large vat (b), add 35.0g of aqueous emulsion (model Rhechem 6014) and 6.0g of aqueous emulsion (model Mowipur 1515) filtered through an 80-micron filter, reduce the speed to 1200 rpm, and then slowly add the dispersed white slurry to the center of the dispersion disk and disperse for 5 minutes.

[0070] 4) Increase the speed to 1500 rpm, add 0.1g wetting agent (BYK-3455), 0.5g leveling agent (MODAREZ PW 336, which should be pre-mixed with the remaining 2.69g pure water), 4g zirconium crosslinker (PC88), 1.0g thickener (RHEOLATE 212), 0.05g thickener (COAPUR 830W), disperse for 15 minutes, take samples to test the appearance of the paint film, and proceed to the next step only after passing the test.

[0071] 5) Reduce the rotation speed to 400 rpm and stir for 10 minutes; filter and package after passing the inspection to obtain the water-based single-component coating of this example.

[0072] Example 2

[0073] A water-based one-component coating, the specific preparation raw materials and amounts are shown in Table 1.

[0074] The water-based one-component coating of this example includes the following preparation steps:

[0075] 1) Take a clean large vat (a), accurately add 2.5g pure water, 0.5g film-forming aid (model commercially available propylene glycol), 2g film-forming aid (model commercially available DPM), 1.5g film-forming aid (model commercially available DPNB), 0.5g film-forming aid (model commercially available TPNB), select a suitable dispersion disk, the ratio of the diameter of the dispersion disk to the diameter of the container is about 0.4-0.6, start stirring at 800rpm, aim at the center of the dispersion disk and add 0.05g pH adjuster (model commercially available AMP-95), 1.6g dispersant (model 755W), 1.0g dispersant (model Afcona4560), 0.2g defoamer (model TEGO FOAMEX 845) in a thin stream, and stir for 5 minutes.

[0076] 2) Keep stirring speed constant, slowly add 38g titanium dioxide (model BLR-895) and 0.01g ultramarine powder (model FERRO ultramarine blue EP-19) in turn. The feeding speed should be such that the powder does not accumulate on the liquid surface. Wash the excess powder on the edge with 1g pure water (manually scrape the cylinder if necessary). After washing, increase the speed to 2200rpm and disperse for 20min until the test fineness is ≤20μm.

[0077] 3) The rotation speed was reduced to 1200 rpm, 35 g of aqueous emulsion (model Rhechem 6014) and 6 g of aqueous emulsion (model Mowipur 1515) were filtered using an 80 μm filter, and then slowly added to the center of the dispersion disk and dispersed for 5 minutes.

[0078] 4) Increase the speed to 1500 rpm, add 0.1g wetting agent (BYK-3455), 0.3g leveling agent (MODAREZ PW 336, which should be pre-mixed with the remaining 3.49g pure water), 5g special cross-linking agent (PC88), 1.2g thickener (RHEOLATE 212), 0.05g thickener (COAPUR 830W), disperse for 15 minutes, take samples to test the appearance of the paint film, and proceed to the next step only after passing the test.

[0079] 5) Reduce the rotation speed to 400 rpm and stir for 10 minutes; filter and package after passing the inspection to obtain the water-based single-component coating of this example.

[0080] Example 3

[0081] A water-based one-component coating, the specific preparation raw materials and amounts are shown in Table 1.

[0082] The water-based one-component coating of this example includes the following preparation steps:

[0083] 1) Take a clean large vat (a), accurately add 2.5g pure water, 0.5g film-forming aid (model commercially available propylene glycol), 2g film-forming aid (model commercially available DPM), 2.0g film-forming aid (model commercially available DPNB), select a suitable dispersion disk, the ratio of the diameter of the dispersion disk to the diameter of the container is about 0.4-0.6, start stirring at 800rpm, aim at the center of the dispersion disk and add 0.05g pH adjuster (model commercially available AMP-95), 1.6g dispersant (model 755W), 1.1g dispersant (model Afcona4560), 0.1g defoamer (model TEGO AIREX 902W), 0.2g defoamer (model TEGO FOAMEX 845) in a thin stream, and stir for 5 minutes.

[0084] 2) Keep stirring speed constant, slowly add 39g titanium dioxide (model BLR-895) and 0.01g ultramarine powder (model FERRO ultramarine blue EP-19) in sequence. The feeding speed should be such that the powder does not accumulate on the liquid surface. Wash the excess powder on the edge with 1.5g pure water (manually scrape the cylinder if necessary). After washing, increase the speed to 2200rpm and disperse for 20min until the test fineness is ≤20μm.

[0085] 3) The rotation speed was reduced to 1200 rpm, 38 g of aqueous emulsion (model: Rhechem 6014) was filtered using an 80 μm filter, and then slowly added to the center of the dispersion disk and dispersed for 5 minutes.

[0086] 4) Increase the speed to 1500 rpm, add 0.1g wetting agent (BYK-3455), 0.2g leveling agent (MODAREZ PW 336, which should be pre-mixed with the remaining 4.04g pure water), 6g special cross-linking agent (PC88), 1.0g thickener (RHEOLATE 212), 0.1g thickener (COAPUR 830W), disperse for 15 minutes, take samples to test the appearance of the paint film, and proceed to the next step only after passing the test.

[0087] 5) Reduce the rotation speed to 400 rpm and stir for 10 minutes; filter and package after passing the inspection to obtain the water-based single-component coating of this example.

[0088] Comparative Example 1

[0089] A water-based two-component coating, the specific preparation raw materials and amounts are shown in Table 1.

[0090] The water-based two-component coating of this example includes the following preparation steps:

[0091] 1) Add 6.5 g of water into the tank (a), turn on the dispersant and control the dispersant speed at 300 r / min, slowly add 0.1 g of pH adjuster (model commercially available AMP-95), 0.3 g of defoamer (model Rhodia RHODOLINE DF-691), 0.1 g of defoamer (model TEGO AIREX 902W), 0.8 g of dispersant (model Dow OROTAN Quick Easy), 0.6 g of dispersant (model Clariant EMULSOGEN LCN 407) and 1 g of commercially available propylene glycol, then slowly add 10 g of commercially available 1250 mesh heavy calcium, 10 g of commercially available 1250 mesh talc and 12 g of titanium dioxide (model Dongjia SR237), then increase the speed to 1200 r / min, disperse evenly, and obtain a pre-slurry;

[0092] 2) 53.4 g of hydroxy acrylic resin was added to the cylinder, stirred, and the prepared slurry obtained in step 1) was slowly added to the cylinder; then 3 g of film-forming aid (model commercially available DPM), 0.8 g of wetting agent (model 04B), 0.2 g of wetting and leveling agent (SILCO WET D-504) and 0.2 g of bactericide and mildew inhibitor (Clariant NIPACIDE CI 15HS) were slowly added, and finally 0.5 g of thickener (model Dow RM-2020) and 0.5 g of thickener (model Dow RM-8W) were added to obtain component A;

[0093] 3) Under the condition of stirring speed of 300 r / min, 10 g of isocyanate curing agent (model Wanhua Aquolin268) was slowly poured into the A component and continued to stir to obtain the water-based two-component coating of this example.

[0094] Comparative Example 2

[0095] A water-based one-component coating, the specific preparation raw materials and amounts are shown in Table 1.

[0096] The water-based one-component coating of this example includes the following preparation steps:

[0097] 1) Add 6 g of water to the cylinder (a), control the dispersant speed at 300 r / min, slowly add 0.2 g of defoamer (model Rhodia RHODOLINE DF-691), 0.2 g of defoamer (model TEGO AIREX 902W), 0.6 g of dispersant (model Dow OROTAN Quick Easy) in sequence, then slowly add 16 g of commercially available 1250 mesh heavy calcium, 6 g of commercially available 1250 mesh talc and 12 g of titanium dioxide (model Dongjia SR237), then increase the speed to 1200 r / min, disperse evenly, and obtain a pre-slurry;

[0098] 2) 52 g of aqueous emulsion (model AC2403) was added to the cylinder (b) and stirred, and the prepared slurry obtained in step 1) was slowly added into the cylinder; then 1 g of film-forming aid (model commercially available propylene glycol), 2 g of film-forming aid (model commercially available DPM), 1.5 g of film-forming aid (model commercially available DPNB), 1.5 g of film-forming aid (model commercially available TPNB), 0.2 g of wetting agent (model BYK-3455), 0.2 g of thickener (model BYK420), 0.2 g of leveling agent (model MODAREZ PW 336) and 0.1 g of bactericide and mildewproofing agent (Clariant NIPACIDE CI 15HS) were slowly added, and finally 0.3 g of thickener (model Dow RM-8W) was added to obtain the water-based one-component coating of this example.

[0099] Comparative Example 3

[0100] A water-based one-component coating, which is different from Example 1 in that 0.8 g of dispersant (model Dow OROTAN Quick and Easy) and 0.2 g of dispersant (model Clariant EMULSOGEN LCN 407) are used in this example, instead of 1.6 g of dispersant (model 755W) and 1.1 g of dispersant (model Afcona4560) in Example 1, the amount of pure water added is increased from 6.69 g to 8.39 g, and other raw materials and preparation methods are the same as those in Example 1.

[0101] Comparative Example 4

[0102] A water-based one-component coating, which differs from Example 1 in that 4 g of tannic acid inhibitor (model Halox Xtain L-44) is used in this example instead of 4.0 g of zirconium crosslinking agent (model PC88) in Example 1. Other raw materials and preparation methods are the same as those in Example 1.

[0103] Comparative Example 5

[0104] A water-based single-component coating, which is different from Example 1 in that 0.01 g of ultramarine powder (model EP-19) is not used in this example, and 0.01 g of pure water is added. Other raw materials and preparation methods are the same as those in Example 1.

[0105] Comparative Example 6

[0106] A water-based one-component coating, which differs from Example 1 in that 41.0 g of water-based emulsion (model Mowipur 6767) is used in this example, instead of 35.0 g of water-based emulsion (model Rhechem 6014) and 6.0 g of water-based emulsion (model Mowipur 1515) in Example 1. Other raw materials and preparation methods are the same as those in Example 1.

[0107] Table 1 Raw materials and their amounts of Examples 1 to 3 and Comparative Examples 1 to 6 (unit: g)

[0108]

[0109]

[0110]

[0111] Performance Testing

[0112] (1) The water-based one-component coatings of Examples 1 to 3 and Comparative Examples 2 to 6 and the water-based two-component coating of Comparative Example 1 were tested according to relevant standards, including viscosity, fineness, non-volatile matter, storage stability, freeze-thaw stability and contrast ratio.

[0113] (2) The water-based paints of Examples 1 to 3 and Comparative Examples 1 to 6 were applied to the furniture surface. First, a layer of the water-based paint was rolled and dried at 80° C. for 30 seconds (or dried at room temperature for 30 minutes). Then, a layer of the water-based paint was rolled and dried at 80° C. for 30 seconds (or dried at room temperature for 30 minutes). Then, a layer of the water-based paint was rolled and dried at 80° C. for 30 seconds (or dried at room temperature for 30 minutes). Then, a layer of the water-based paint was rolled and dried at 80° C. for 30 seconds (or dried at room temperature for 30 minutes) to obtain a paint film. The gloss, hardness, polishability and adhesion of the paint film were tested according to relevant standards. In addition, the sealing property of the paint film was tested according to the following method: white rubber was taken. The water-based coatings of Examples 1 to 3 and Comparative Examples 1 to 6 and a commercially available closed high-hiding PU white primer are applied 2 coats each on the surface of the substrate under the same conditions. The result of the closed high-hiding PU white primer on the substrate board is used as a benchmark score of 1-10, with the highest being 10. The closed high-hiding PU white primer has a base score of 8. The test results are visually compared with the benchmark board test results, and the results are scored by weighted average. The higher the average value, the better the closed property.

[0114] The test results are shown in Table 2.

[0115] Table 2 Coating properties of Examples 1 to 3 and Comparative Examples 1 to 6

[0116]

[0117]

[0118] As can be seen from Table 2, the fineness, non-volatile matter, storage stability, and freeze-thaw stability of the water-based single-component coatings obtained in Examples 1 to 3 all meet the test indicators. However, the water-based two-component coating of Comparative Example 1 and the water-based single-component coating of Comparative Example 2 are not as good as the water-based single-component coatings obtained in Examples 1 to 3 in terms of fineness, contrast ratio, storage stability, gloss, hardness, and sealing properties; the water-based single-component coating of Comparative Example 3 is lower than that of Example 1 in terms of fineness, contrast ratio, sealing properties, and gloss; the water-based single-component coating of Comparative Example 4 is significantly lower than that of Example 1 in terms of fineness, storage stability, and freeze-thaw stability, among which the storage stability and freeze-thaw stability are abnormal and do not meet the requirements of the national standard GB / T 23999-2009; the water-based single-component coating of Comparative Example 5 is lower than that of Example 1 in terms of contrast ratio and sealing properties; the water-based single-component coating of Comparative Example 6 is lower than that of Example 1 in terms of gloss, hardness, polishability, and adhesion.

[0119] Regarding the sealing property, the sealing property scores of Examples 1 to 3 are very high, indicating that the water-based one-component coatings obtained in Examples 1 to 3 of the present invention have excellent sealing effects; while the water-based two-component coating of Comparative Example 1 and the water-based one-component coating of Comparative Example 1 were applied to the surfaces of substrates such as white oak, red oak, ash, teak, bean wood, and ash. After evaluation, their sealing property scores were average, indicating that the coatings of Comparative Examples 1 to 2 had average sealing effects; the sealing property scores of Comparative Examples 3 and 5 were also relatively low, and the sealing effects were relatively average.

[0120] The coatings of Examples 1 to 3 of the present invention solve the following problems: 1. The main paint has good storage stability, avoiding the problem of substantial post-thickening (or gelling) of the main paint caused by adding tannic acid inhibitors in the prior art. The main paint of the present invention is stored at 50°C for 1 week with a viscosity change of ≤20% and a fineness of ≤35 μm. 2. Good sealing performance. By adding zirconium cross-linking agents, it reacts with tannic acid and the like that seeps out of wood or furniture to form a dense structure, which can quickly establish protection and avoid the seepage of wood tannin components, which causes the yellowing of the paint film. 3. When roller coating is applied, it has good hiding power: contrast ratio ≥0.95, and good adhesion: ≤1 level.

[0121] It can be seen that the water-based single-component coatings obtained in Examples 1 to 3 of the present invention have good effects in terms of fineness, contrast ratio, storage stability, closure, gloss, hard work, polishability and adhesion, etc., can achieve a balance of various properties, and have good comprehensive performance. The paint film obtained by using the coatings in Examples 1 to 3 of the present invention has good density, has a closure effect on various substrates, has good closure on solid wood substrates such as white oak, red oak, ash, teak, round bean wood, ash, or other types of wood, and the coating of the present invention can be directly roller-coated, does not need to apply a closed primer separately, has high construction efficiency, does not turn yellow in the later stage of the paint film, has good covering power and strong adhesion. The coatings in Examples 1 to 3 of the present invention also have the characteristics of good adhesion, good impact resistance, fast drying speed, etc., and the construction method can be artificial roller coating or equipment roller coating, which can be used for factory coating and DIY coating. In addition, the paint film has a high solid content, a high coating amount in a single roller coating, a high hiding power, and can reduce the number of construction times. The paint film dries quickly, and the drying time is about 30 seconds at 80°C or 15 minutes at room temperature. The paint can be produced continuously during roller coating, and can be packaged after it comes off the line, thereby improving construction efficiency, reducing production costs, and obtaining good construction effects with fewer coating times, which can significantly reduce construction costs. Therefore, the present invention effectively overcomes various shortcomings in the prior art and has a high industrial utilization value.

[0122] In summary, the present invention adopts a zirconium cross-linking agent that does not contain ammonium or amine, which can not only react with tannic acid that penetrates from wood or wooden articles, but also react with residual carboxyl groups in aqueous emulsion systems such as aqueous acrylic emulsion, aqueous polyurethane-modified acrylic emulsion or aqueous polyurethane emulsion to form good cross-linking, thereby greatly improving the sealing property of the paint film and improving the problem of yellowing of the paint film; in addition, in combination with acrylic polymer dispersants, color fillers, functional pigments, and functional additives, the comprehensive properties of the coating system such as dispersibility, compatibility, hiding power, storage stability and construction performance can be further improved.

Claims

1. A water-based one-component coating, characterized in that: The invention comprises the following raw materials in parts by weight: 30 to 70 parts of aqueous emulsion, 1 to 10 parts of cross-linking agent, 0.5 to 5 parts of dispersant, 1 to 20 parts of functional additive, 10 to 50 parts of color filler, 0.001 to 1 part of functional pigment, and 2 to 20 parts of water; the aqueous emulsion comprises at least one of aqueous acrylic emulsion, aqueous polyurethane modified acrylic emulsion or aqueous polyurethane emulsion; the cross-linking agent is selected from zirconium cross-linking agents that do not contain ammonium or amine; the dispersant comprises acrylic polymer dispersant, modified acrylic polymer dispersant or a combination thereof.

2. The water-based one-component coating according to claim 1, characterized in that: The zirconium cross-linking agent is selected from zirconium carbonate salts; and / or, the pH value of the zirconium cross-linking agent is 8 to 10; And / or, the effective component of the zirconium-based cross-linking agent is ≥ 30 wt%.

3. The water-based one-component coating according to claim 1, characterized in that: The acid value of the acrylic polymer dispersant is 10 to 20 mgKOH / g; And / or, the modified acrylic polymer dispersant is selected from amine-modified acrylic polymer dispersants; the amine value of the amine-modified acrylic polymer dispersant is preferably 18 to 30 mgKOH / g.

4. The water-based one-component coating according to claim 1, characterized in that: The aqueous emulsion includes aqueous acrylic emulsion, aqueous polyurethane-modified acrylic emulsion or a combination thereof.

5. The water-based one-component coating according to any one of claims 1 to 4, characterized in that: The aqueous emulsion includes Rhechem 6014, Argo Mowipur 1515 or a combination thereof; and / or, the crosslinking agent is selected from Archroma Mowiplus PC 88; And / or, the dispersant comprises TEGO Dispers 755W, AFCONA 4560 or a combination thereof.

6. The water-based one-component coating according to claim 1, characterized in that: The pigment and filler are selected from titanium dioxide; the titanium dioxide preferably includes rutile titanium dioxide from the sulfate process, rutile titanium dioxide from the chloride process or a combination thereof; And / or, the functional pigment is selected from ultramarine blue powder.

7. The water-based one-component coating according to claim 1, characterized in that: The functional additives include at least one of a pH regulator, a film-forming aid, a defoamer, a wetting agent, a leveling agent or a thickener; Preferably, the pH adjuster is selected from organic amine compounds; and / or, the film-forming aid comprises propylene glycol, an alcohol ether compound or a combination thereof; And / or, the defoamer is selected from silicone defoamers; and / or, the wetting agent is selected from silicone wetting agents; And / or, the leveling agent is selected from acrylic leveling agents; And / or, the thickener includes a polyurethane thickener, a polyether modified thickener or a combination thereof.

8. A method for preparing a water-based one-component coating according to any one of claims 1 to 7, characterized in that: The following steps are involved: First, the dispersant, part of the functional additives and water are mixed for the first time, then the color filler and the functional pigment are added for the second mixing, then the aqueous emulsion is added for the third mixing, and finally the crosslinking agent and the remaining functional additives are added for the fourth mixing to obtain the aqueous single-component coating.

9. The preparation method according to claim 8, characterized in that: The first mixing speed is 700-900 rpm; and / or, the second mixing speed is 2000-2400 rpm; And / or, the rotation speed of the third mixing is 1000-1400 rpm; And / or, the fourth mixing speed is 1300-1700 rpm.

10. Use of the water-based one-component coating according to any one of claims 1 to 7 in the preparation of water-based wood coatings.

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