TW202136350A - Waterborne uv curable coating composition for anti-stain and anti-scratch coatings - Google Patents

Abstract

The invention relates to an aqueous dispersion containing a mixture of fluorinated and non-fluorinated polyurethane acrylates, obtainable by: a) reacting polyisocyanate A’, multi-unsaturated OH-functional compound B’, acid-functional polyol C’ under urethane formation reaction conditions in the presence of intermediate X, wherein intermediate X is an OH-functional (per)fluoropolyether (PFPE) derivative, and b) adding neutralizer D to the reaction product of step a) and dispersing in water. The dispersion can be used in preparation of a coating with easy-clean, anti-stain and anti-scratch properties, which can advantageously be used for coating substrates in consumer electronics or automotive applications.

Description

Water-based UV curable coating composition for anti-fouling and anti-scratch coatings

The present invention relates to an aqueous dispersion, which can be used to prepare water-based UV curable coating compositions for anti-fouling and scratch-resistant coatings. These coatings can be particularly used in the field of consumer electronics or automotive coatings.

In the field of consumer electronic devices (such as mobile phones, desktop computers, laptop computers, and car interiors), various substrates such as plastic, metal, and glass are used. It is generally desirable to cover these substrates with an easy-to-clean, stain-resistant and scratch-resistant coating. Easy to clean means that the surface is repellent to water, oil and/or dirt. The easy-to-clean coating reduces or eliminates the need to clean the surface.

Fluorinated polymers are known in the art, in particular (per)fluoropolyether (PFPE) has non-stick and lubricating properties and can be used to produce easy-to-clean and anti-fouling coatings. However, these resins are only soluble in fluorinated solvents and are therefore difficult to use in coating formulations without the use of dedicated solvents. When we want to use these resins in water-based coating compositions, the problem is even greater, because fluorinated resins generally do not disperse well in water. Therefore, the improvement of antifouling properties is usually accompanied by the deterioration of water dispersibility. As a result, most antifouling coatings are usually solvent-based. Another problem with using PFPE-based polymers is that they generally do not have good scratch resistance.

CN109054623 describes an aqueous dispersion of light-curable polyurethane acrylate. Polyurethane acrylate is prepared from diisocyanate, dimethylolpropionic acid, organofluoropolysiloxane polyol to obtain polyurethane prepolymer, and then react with hydroxyl-containing acrylate To obtain a blocked polyurethane acrylate. The organic amine and deionized water are added to the obtained polymer to obtain a photocurable polyurethane acrylate aqueous dispersion. The coatings prepared from this dispersion have high stain resistance and durability.

US2017049683 describes a nail polish composition based on a solvent-free aqueous polyurethane polymer dispersion, which is derived from a chain extension reaction using a chain extender with isocyanate reactive groups and then in a reactive diluent At least one isocyanate-terminated ethylenically unsaturated polyurethane prepolymer. The polyurethane prepolymer contains at least one (meth)acrylate functional group and at least one isocyanate functional group.

CN109293871 describes a self-leveling water-based fluorine-containing urethane acrylic resin for photocurable coatings. The resin is prepared from the following raw materials in the following mass percentages: 10 to 20% trimer polyisocyanate, 10 to 25% monohydroxy acrylate, 2 to 10% perfluoropolyether glycol, 1 to 2% trimethylol Methyl propane, 2 to 6% dimethylolpropionic acid, 1 to 3% neutralized amine, 40 to 60% water, 4 to 7% acetone, 0.01 to 0.1% catalyst, and 0.1 to 1% polymerization initiator. The resin has excellent water dispersibility, good stability, milky white appearance with blue light, high resin solid content and medium viscosity. The obtained coating has good stability, strong impact resistance and good spreadability.

There is a need to provide an antifouling coating composition that can be formulated into a water-based coating composition. It is also expected that these coatings will be durable, stain resistant and at the same time scratch resistant. It is further expected that the coating will adhere well to substrates (in particular, plastic substrates) used in consumer electronics or the automotive industry.

In order to solve the aforementioned expectations, in the first aspect, the present invention provides an aqueous dispersion containing a mixture of fluorinated and non-fluorinated polyurethane acrylates, which can be obtained by: a) The polyisocyanate A', the polyunsaturated OH-functional group-containing compound B', and the acid-functional group-containing polyol C'are reacted in the presence of intermediate X under the conditions of the urethane formation reaction, wherein the intermediate X is An OH-functional (per)fluoropolyether (PFPE) derivative present in an amount of 0.1-10% by weight of the total weight of the reaction mixture based on the solid weight, wherein no compound with a functionality of 3 or higher is used, b) Add the neutralizer D to the reaction product of step a) and disperse it in water, Among them, Intermediate X is selected from the list of the following components: i. Hydroxy-terminated (per)fluoropolyether, ii. The reaction product of PFPE diol with polyisocyanate A and polyol C containing acid functional groups under the conditions of urethane formation, and iii. The reaction product of PFPE diol with polyisocyanate A, polyunsaturated OH functional group-containing compound B and acid functional group-containing polyol C under urethane formation conditions.

In another aspect, the present invention provides a water-based UV curable coating composition comprising the aqueous dispersion according to the present invention.

The present invention also provides a method for coating a substrate, which includes applying the coating composition according to the present invention to the substrate and curing the coating composition with UV radiation.

In another aspect, the present invention provides a coated article obtained according to the present invention.

The present invention provides an aqueous dispersion containing a mixture of fluorinated and non-fluorinated polyurethane acrylates. The fluorinated polymer is based on (per)fluoropolyether (PFPE). Polyurethane acrylate has ionic dispersing groups (for example, acidic groups) that help its dispersibility in water. In order to obtain a mixture of the above-mentioned polymers, it is necessary to carry out the polyurethane synthesis in one step ("one-pot synthesis") and carry out the synthesis in the presence of the specific fluorinated intermediate X.

Intermediate X Intermediate X is a PFPE derivative containing OH functional groups. (Per)fluoropolyether (PFPE) is a fluorinated polymer containing a linear or branched fully or partially fluorinated polyoxyalkylene chain, the chain containing repeats with at least one chain ether bond and at least one fluorocarbon moiety unit. PFPE can be divided into non-functional groups and functional groups; the former contains a PFPE chain with a (per)haloalkyl group at its end, and the latter contains a PFPE chain with at least two ends, at least one of which contains a functional group. The functional group PFPE (specifically monofunctional and bifunctional PFPE) includes a PFPE chain with two ends, one or both ends of which have functional groups. Preferably, a bifunctional PFPE is used.

The OH functional group-containing PFPE derivatives that can be used as intermediate X in the present invention are selected from the list consisting of: i. Hydroxy-terminated (per)fluoropolyether (X1), ii. The reaction product (X2) of PFPE diol, polyisocyanate A and acid-functional polyol C under the conditions of urethane formation, and iii. The reaction product of PFPE diol and diisocyanate A, polyunsaturated OH functional group-containing compound B and acid functional group-containing polyol C under urethane formation conditions (X3).

Intermediate X1 Intermediate X1 can be a hydroxyl-terminated (per)fluoropolyether, which contains one or more OH groups at each of the two ends, preferably one OH group at each end Functional group (per)fluoropolyether (PFPE). The end group may also be -CH ₂ OH. These compounds can also be referred to as PFPE diols. The hydroxyl-terminated (per)fluoropolyether preferably has a number average molecular weight of 400 to 3000. Mn can be determined by gel permeation chromatography (GPC) using polystyrene standards using tetrahydrofuran as the mobile phase.

The hydroxyl-terminated (per)fluoropolyether can have the general structure HO-(CF ₂ -CF ₂ -O) _n -OH or HO-(CF ₂ -CF ₂ -O) _n -(CF ₂ -O) _m- OH. It may also contain blocks with ethylene oxide units and have a general structure: HO-(CH ₂ CH ₂ O) _p -CH ₂ -CF ₂ -R _f -CF ₂ -CH ₂ -(OCH ₂ CH ₂ ) _q -OH wherein p and q are integers independently selected from 0 to 50, preferably 1 to 50, wherein R _f represents a (per)fluoropolyether structure (CF ₂ CF ₂ O) _n , (CF ₂ O ) _m or (CF ₂ -CF ₂ -O) _n -(CF ₂ -O) _m difunctional group, and wherein n and m are integers independently selected from 1 to 100. When both p and q are non-zero, the resulting polymer has better dispersibility in water. Preferably, p is in the range of 1 to 5 and q is in the range of 1 to 5. It is also possible to use -CH ₂ OH groups instead of -OH groups.

Hydroxy-terminated (per)fluoropolyether is purchased from Solvay with Fluorolink® PFPE or Fomblin® PFPE, for example, Fluorolink® 5174X, Fluorolink® E10H, Fluorolink® PEG45.

Intermediate X2 is the second option. Intermediate X can be the reaction product of PFPE diol, polyisocyanate A and polyol C containing acid functional groups. After the reaction, the intermediate X2 is both a hydroxyl-containing functional group and an acid-containing functional group.

The PFPE diol may be the same as or different from the hydroxyl-terminated (per)fluoropolyether described above for X1. During the preparation of X2, the amount of PFPE diol is preferably in the range of 10 to 90% by weight, more preferably 20 to 80% by weight, based on the total weight of the reaction mixture.

The polyisocyanate A is a compound having a reactive isocyanate group and has a functionality of at least 2. Mixtures of polyisocyanates can also be used. The polyisocyanate can be aliphatic or aromatic. Examples of suitable polyisocyanates include hexamethylene diisocyanate, 2,2,4- and/or 2,4,4-trimethylhexamethylene diisocyanate, p- and meta-tetramethyl xylene diisocyanate , Methylene bis(4-cyclohexyl isocyanate) (hydrogenated MDI), 4,4-methylene diphenyl isocyanate (MDI), p-and m-phenylene diisocyanate, 2,4-and/or 2,6-Toluene diisocyanate (TDI) and its adducts, and isophorone diisocyanate (IPDI). Preferred polyisocyanates include aliphatic diisocyanates such as IPDI and hexamethylene diisocyanate. Preferably, IPDI is used.

During the preparation of X2, the amount of A is preferably in the range of 0.1 to 20% by weight, more preferably 1 to 10% by weight, based on the total weight of the reaction mixture.

The acid functional group-containing polyol C has both acidic and hydroxyl functional groups. Preferably, the acid functional group-containing polyol C is a diol. Preferably, it contains at least one carboxylic acid group. Preferably, the carboxyl group is a tertiary acid group.

其中R為氫或C_1-16 烷基。較佳地，R為C₁ -C₃ 烷基。更佳地，化合物C為2,2-二羥甲基丙酸(DMPA)或2,2-二羥甲基丁酸(DMBA)。此等化合物可自市面上購得，例如自GEO Chemicals之DMPA HA-0135。Preferably, compound C has the following formula:

Where R is hydrogen or C _1-16 alkyl. Preferably, R is a C ₁ -C ₃ alkyl group. More preferably, compound C is 2,2-dimethylolpropionic acid (DMPA) or 2,2-dimethylolbutanoic acid (DMBA). These compounds are commercially available, such as DMPA HA-0135 from GEO Chemicals.

Alternatively, the acid-containing functional group can also be derived from a sulfonic acid group, for example, an alkyl or aryl sulfonate. Examples include the salts of 2-((2-aminoethyl)amino)ethanesulfonate, 2,4-diaminobenzenesulfonate, and specifically the sodium salt thereof.

Compound C may also be a polymer, for example, a linear polyester polyol containing acid functional groups. These compounds are commercially available, for example, DMPA polyol HA-0135LV and DMPA polyol HA-0135 from GEO Chemicals. If compound C is a polymer, it preferably has an OH value of 20 to 190, more preferably 50 to 150 mg KOH/g resin. It preferably has an acid value of 20 to 250, more preferably 50 to 200 mg KOH/g resin. The acid value can be measured by potentiometer titration (for example, according to DIN EN ISO 3682). The hydroxyl value can be measured by potentiometric titration using the TSI method (for example, according to ASTM E1899-08).

The reaction with the acid functional group-containing polyol C allows the introduction of acidic groups into the polymer chain, which contributes to the water dispersibility of the resulting polyurethane acrylate.

During the preparation of X2, the amount of C is preferably in the range of 0.1 to 20% by weight, more preferably 0.5 to 10% by weight, based on the total weight of the reaction mixture.

In the preparation of X2, other compounds other than those mentioned above can also be used, which can react under the conditions of urethane formation. However, it is preferable not to use a compound having a functionality of 3 or more. Herein, functionality means hydroxyl or isocyanate functionality. Examples of such compounds include polyols such as trimethylolpropane. These compounds introduce branches in the polymer chain. Branching can cause viscosity problems. Therefore, in the present invention, the obtained polymer is preferably linear and unbranched.

The reaction conditions for forming the urethane compound are generally known to those skilled in the art. The reaction temperature can be in the range of 40 to 160°C, preferably in the range of 50 to 100°C. Conventional catalysts can be used, such as dibutyl tin dilaurate (DBTDL), stannous octoate, diazabicyclo (2.2.2) octane (DABCO), Zn ACAC, tin octoate. The amount of the catalyst is preferably 0.005 to 1 part by weight per 100 parts by weight of the urethane-forming monomer. Suitable solvents can be used, such as n-butyl acetate, N-methyl-pyrrolidone, and toluene. Preferably, the solvent is miscible with water.

The reaction with the acid functional group-containing polyol C can be carried out after the reaction with the polyisocyanate A or at the same time.

Preferably, the reaction with the polyisocyanate A is performed first, and then the acid functional group-containing polyol C is added. In this case, the first reaction is carried out with an excess of isocyanate molar. The molar excess of A is preferably in the range of 1.1 to 5, more preferably in the range of 2 to 4.

The progress of the reaction is monitored by analyzing the NCO content over time. When the NCO content is no longer detected, the reaction is stopped.

The intermediate X2 preferably has a number average molecular weight of 400 to 3000, more preferably 500 to 2000. Mn can be determined by gel permeation chromatography (GPC) using polystyrene standards using tetrahydrofuran as the mobile phase.

As a third option Intermediate X3, X3 intermediates may be used, which is a PFPE diol with polyisocyanates A, polyunsaturated reaction product containing OH functional groups of compound B and an acid functional group of the polyol C. The obtained intermediate X3 contains both a hydroxyl functional group and an acid functional group, and also contains an unsaturated (for example, acrylate) functional group.

The PFPE diol may be the same as or different from the hydroxyl-terminated (per)fluoropolyether described above for X1. Polyisocyanate A and acid functional group-containing polyol C can be used as described above for X2. During the preparation of X3, the amount of PFPE diol is preferably in the range of 10 to 90% by weight, more preferably 15 to 60% by weight, based on the total weight of the reaction mixture. The amount of A is preferably in the range of 0.1 to 30% by weight, more preferably 1 to 20% by weight, based on the total weight of the reaction mixture. The amount of C is preferably in the range of 0.1 to 20% by weight, more preferably 0.5 to 10% by weight, based on the total weight of the reaction mixture.

The polyunsaturated OH-functional group-containing compound B is preferably an OH-functional group-containing (meth)acrylate monomer, which is added to other reagents under the conditions of the urethane formation reaction.

The OH functional group-containing (meth)acrylate monomer B has at least one OH group and preferably has 1 to 5 (meth)acrylate groups. More preferably, it has only one hydroxyl group (monofunctional alcohol). It is preferable to use a compound having a molecular mass of not higher than 1,500. Suitable compounds include (meth)acrylates of polyhydric alcohols (e.g., ethylene glycol, pentaerythritol, and dipentaerythritol). Examples include 2-hydroxyethyl (meth)acrylate, pentaerythritol (meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, (meth)acrylic acid Dipentaerythritol, dipentaerythritol di(meth)acrylate, dipentaerythritol tri(meth)acrylate, dipentaerythritol tetra(meth)acrylate, and dipentaerythritol penta(meth)acrylate. The preferred compound E is dipentaerythritol pentaacrylate (DPPA) or its mixture with dipentaerythritol hexaacrylate (DPHA).

During the preparation of X3, the amount of B is preferably in the range of 0.1 to 60% by weight, more preferably 1 to 50% by weight, based on the total weight of the reaction mixture.

Similar to X2, in the preparation of X3, other compounds other than those mentioned above can also be used, which can react under the conditions of urethane formation. However, it is also preferable not to use a compound having a functionality of 3 or more.

The reaction of PFPE with compounds A, B and C can be carried out simultaneously or in any order. For example, the reaction of PFPE and compound A can be carried out first, then compound B and then compound C can be added. All reaction steps are preferably carried out under urethane formation conditions. Suitable reaction conditions for the formation of urethane are known to those skilled in the art. In general, the conditions described above for Intermediate X2 can be used. The progress of the reaction can be monitored by analyzing the NCO content over time. When the NCO content is no longer detected, the reaction is stopped.

The intermediate X3 preferably has a number average molecular weight of 400 to 3000, more preferably 800 to 2500. Mn can be determined by gel permeation chromatography (GPC) using polystyrene standards using tetrahydrofuran as the mobile phase.

After both steps (b) and (c) (in any order), an unsaturated polyurethane containing a carboxyl functional group is obtained. The polyurethane preferably has a linear structure. The polyurethane preferably has a weight average molecular weight Mw in the range of 2,000 to 20,000, more preferably in the range of 4,000 to 15,000. The polyurethane preferably has a number average molecular weight Mn in the range of 800 to 5,000, more preferably 1,000 to 3,000.

The resulting polyurethane preferably has an acid value in the range of 10 to 50 mg KOH/g. The acid value can be measured by potentiometric titration (for example, according to DIN EN ISO 3682). Preferably, the resulting polyurethane does not have OH functional groups. The hydroxyl value is preferably <5 mg KOH/g, more preferably 0 mg KOH/g. The hydroxyl value can be measured by potentiometric titration using the TSI method (for example, according to ASTM E1899-08).

Aqueous dispersion After intermediate X is provided or prepared as described above, the aqueous dispersion according to the present invention can be prepared by a method including the following steps.

Step (a) In step (a), the polyisocyanate A′ is reacted with the polyunsaturated compound B′ and the acid functional group-containing polyol C′ in the presence of the intermediate X under the reaction conditions of urethane formation.

As the polyisocyanate A', the polyisocyanate described above for the polyisocyanate A can be used. The polyisocyanate A'may be the same as or different from the polyisocyanate A used in the synthesis of intermediate X2 or X3 (if X2 or X3 is used in this step). The amount of A'used in the reaction is preferably in the range of 0.1 to 50% by weight, more preferably 1 to 30% by weight, based on the total weight of the reaction mixture.

As the polyunsaturated OH functional group-containing compound B', the compounds described above for compound B can be used. The polyunsaturated compound B'may be the same as or different from the compound B used in the synthesis of intermediate X3 (provided that X3 is used in this step). The amount of B'used in the reaction is preferably in the range of 10 to 90% by weight, more preferably 20 to 80% by weight, based on the total weight of the reaction mixture.

As the acid functional group-containing polyol C', the acid functional group-containing polyol described above for compound C can be used. It may be the same as or different from the acid functional group-containing polyol C used in the synthesis of intermediate X2 or X3 (if X2 or X3 is used in this step). The amount of C'used in the reaction is preferably in the range of 0.1 to 20% by weight, more preferably 1 to 10% by weight, based on the total weight of the reaction mixture.

In preparing the dispersion, no reactive compound with a functionality of 3 or higher is used. Examples of such compounds include polyols such as trimethylolpropane. These compounds introduce branches in the polymer chain, which can cause viscosity problems. Therefore, in the present invention, the obtained polymer is preferably linear and unbranched.

Intermediate X is preferably only present in a small amount during synthesis. Specifically, the amount of intermediate X is 0.1 to 10% by weight, more preferably 0.2 to 5% by weight, based on the solid weight of X relative to the total weight of the reaction mixture. The use of a small amount of intermediate X in step (a) allows to obtain a mixture of fluorinated and non-fluorinated resins in an optimal ratio instead of the main fluorinated resin. If there is too little fluorinated resin, the coating does not exhibit sufficient easy-to-clean properties. If too high amounts of fluorinated resin are present in the resulting resin mixture, it is believed that some of the coating properties will be impaired. It has also been found that high amounts of fluorinated resin are not necessary to achieve the required easy-to-clean and anti-fouling properties. The preparation of intermediate X as described above can be quite expensive due to the fluorine-containing reactant PFPE diol.

The reaction conditions are those that form the urethane compound. These are known to those who are familiar with the technology. In general, the above-mentioned conditions for the synthesis of X2 can be used. Preferably, the synthesis is performed in a solvent (such as those mentioned above for synthesis X2).

The reaction of step (a) produces a mixture of fluorinated and non-fluorinated polyurethane acrylates, which preferably have a linear structure. These polyurethane acrylates contain acid functional groups that help dispersibility in water and also contain unsaturated functional groups (for example, acrylates) for UV curing properties.

In the obtained resin mixture, the non-fluorinated resin preferably constitutes at least 50% by weight of the total weight, more preferably at least 70% by weight, even more preferably at least 90% by weight. The best results are achieved when only 0.1 to 10% by weight of the resin (preferably 0.1 to 5% by weight, based on the total weight of the resin mixture) in the final resin mixture is fluorinated.

Step (b) In step (b), the reaction product of step (a) is neutralized with a neutralizing agent D and dispersed in water.

Neutralizers for acid-functional resins are known. For example, the neutralizer D may be ammonia or a tertiary amine or a mixture of amines. The neutralizer D is preferably a saturated tertiary amine, for example, triethylamine, tripropylamine, triethanolamine, diethylenetriamine, methylamine, and N,N-dimethylethanolamine (DMEA). Preferably, DMEA is used. The advantage of using saturated tertiary amines (such as DMEA) is that the resulting polymer is better dispersible in water.

The neutralizer D is preferably added in an amount to achieve 20 to 150%, more preferably 80 to 120%, of the degree of neutralization of the acid groups of the polyurethane, and the degree of neutralization is calculated as derived from the neutralizer The molar ratio of the base to the carboxylic acid group from the polyurethane.

The resulting neutralized mixture of polyurethane acrylate can be dispersed in water.

The aqueous dispersion preferably has a solid content in the range of 1 to 70% by weight.

The obtained aqueous dispersions of fluorinated and non-fluorinated resins can be used to prepare coating compositions.

Coating composition In another aspect, the present invention provides a water-based UV curable coating composition comprising the above-mentioned aqueous dispersion. The uniqueness of the aqueous dispersion is that in order to achieve the required coating properties, such as easy-to-clean, anti-fouling and scratch-resistant coatings, no other binder resin is required to be present in the coating composition. A coating composition containing a non-fluorinated resin with a separately added fluorine-containing additive may exhibit compatibility problems, which is not the case with the coating composition of the present invention. Therefore, preferably, no other binder resin is present in the coating composition.

The coating composition preferably contains 10 to 99% by weight of the aforementioned aqueous dispersion, based on the total weight of the coating composition.

Although not necessary, additional binder resins can be used in the coating composition. Therefore, in some embodiments, the coating composition contains at least one polymer, which is preferably different from the aforementioned polyurethane acrylic. The additional binder resin can be, for example, polyester, polyurethane, poly(meth)acrylate. Preferably, the additional polymer is poly(meth)acrylate. "Poly(meth)acrylate" polymers are understood to have crosslinkable (meth)acrylate functional groups. Examples include not only poly(methyl methacrylate), poly(methacrylic acid), polymethacrylate, poly(ethyl methacrylate), poly(2-hydroxyethyl methacrylate), but also polyamine Carbamate (meth)acrylate or polyester (meth)acrylate.

The coating composition may also include copolymerizable monomers and oligomers. Examples of such monomers include (meth)acrylate monomers, specifically methyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate Esters, isobutyl (meth)acrylate, ethylhexyl (meth)acrylate, dipentaerythryl hexaacrylate, acrylonitrile, methacrylamide. Vinyl monomers can also be used, for example, vinyl acetate, vinyl propionate, vinyl butyrate, styrene.

Preferably, the coating composition contains at least one photoinitiator or a mixture thereof. When exposed to radiant energy, the photoinitiator generates free radicals. Any suitable UV photoinitiator known in the art can be used. Suitable photoinitiators include benzoin derivatives, biphenyl ketal (benzile) ketal, α-hydroxyalkyl phenone, mono-amino phosphine oxide (MAPO) and bis-amino phosphine oxide (BAPO), such as diphenyl (2 ,4,6-trimethylbenzyl)phosphine oxide, 1-hydroxy-cyclohexyl-phenyl-ketone, bis(2,4,6-trimethylbenzyl)-phenylphosphine oxide, Bis(2,6-dimethoxybenzyl)-2,4,4-trimethylpentyl-phosphine oxide, 2-hydroxy-2-methyl-1-phenyl-propan-1-one , 2-Methyl-1[4-(methylthio)phenyl]-2-morpholinyl-propan-1-one, methyl phenylglyoxylate. Mixtures of these compounds can also be used. The photoinitiator is purchased from, for example, IGM Resins.

The photoinitiator is preferably present in an amount of 0.1 to 10% by weight (for example, 0.5 to 5.0% by weight or 0.5 to 2.5% by weight) based on the total weight of the composition.

Preferably, the coating composition does not contain silicon-containing polymers, specifically silicon-containing film-forming (adhesive) resins.

The coating composition is preferably water-based. When preparing and/or applying the coating composition, the water-based coating composition contains water as the main liquid phase. "Main liquid phase" means that water constitutes at least 50% by weight of the liquid phase, preferably at least 80% by weight, more preferably at least 90% by weight, and in some embodiments, even 100% by weight. The coating composition preferably contains 20 to 80% by weight of water, based on the total weight of the coating composition.

Optionally, the coating composition may additionally contain an organic solvent. For example, the organic solvent may account for up to 40% by weight of the liquid phase, preferably up to 30% by weight. In some embodiments, the coating composition contains less than 10% by weight of organic solvent based on the total weight of the coating composition, preferably less than 5% by weight, or even no organic solvent may be preferable.

Examples of suitable organic solvents include alcohols (such as ethanol, isopropanol, n-butanol, n-propanol), esters (such as ethyl acetate, propyl acetate), aromatic solvents (such as toluene), ketone solvents (such as acetone, Methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, diacetone alcohol); aliphatic hydrocarbons; chlorinated hydrocarbons (such as CH ₂ Cl ₂ ); ethers (such as diethyl ether, tetrahydrofuran, propylene glycol monomethyl ether) and Its mixture. Preferably, the solvent is miscible with water. Preferred organic solvents include butyl acetate, methyl isobutyl ketone (MIBK), methyl ethyl ketone (MEK), propylene glycol monomethyl ether and methoxy propyl acetate (PMA) or mixtures thereof.

The solid content of the coating composition according to the present invention may be in the range of 1 to 90% by weight, preferably 5 to 65% by weight, more preferably 10 to 50% by weight.

The coating composition may further include conventional additives, such as fillers, antioxidants, matting agents, pigments, wear resistant particles, flow control agents, surfactants, plasticizers, adhesion promoters, thixotropic agents, light stabilizers and other.

The present invention provides a coating composition which does not require the presence of a high amount of fluorinated resin in order to have the required properties in terms of easy cleaning, stain resistance and scratch resistance of the coating. In addition, due to the one-pot synthesis, the binder resin (representing a mixture of fluorinated and non-fluorinated polyurethane acrylate) has good compatibility.

The present invention further provides a method for coating a substrate, which includes applying the coating composition according to the present invention to the substrate and curing the coating composition by means of UV radiation.

The coating composition can be applied to a wide range of substrates by conventional techniques (including spraying, roller coating, knife coating, pouring, brushing or dipping). After evaporating water and optional organic solvents (if present), the coating composition produces a coating which is delimed and dried to a little stickiness.

The curing is then induced by means of UV radiation. Any suitable UV radiation source can be used, for example, Hg lamps, metal halide lamps, xenon lamps, UV-LED lamps. Preferably, UV-LED lamps are used. Those familiar with this technology can determine the appropriate conditions for curing by UV radiation.

The curing of the coating composition can be carried out under ambient conditions (e.g., room temperature). Room temperature here should be understood as 15 to 30°C. Curing can also be accelerated by heating. The coated substrate can be heated to a temperature in the range of 40 to 100°C, more preferably 50 to 80°C. A conventional method can be used, for example, putting in an oven. Preferably, heating is performed before or simultaneously with UV curing.

The coating composition according to the present invention can be applied to a wide range of substrates, including metal or non-metal substrates. Suitable substrates include polycarbonate acrylonitrile butadiene styrene (PC/ABS), polycarbonate, polyacrylate, polyolefin, polyamide, polystyrene, glass, wood, stone, aluminum, aluminum alloy.

The coating composition according to the present invention can be used as a single layer directly applied to a substrate, or in a multi-layer system (for example, as a primer, base coat or clear coat).

The coating composition according to the present invention can be used in various coating industries, such as consumer electronics, automobiles, packaging, wood floors and furniture, household appliances, glass and windows, and sports equipment.

The present invention further provides an article comprising a substrate coated with a coating obtained from the coating composition of the present invention. The coating according to the present invention has particularly good general properties, including adhesion and scratch resistance. In addition, these coatings also have excellent easy-to-clean and anti-fouling properties, such as permanent markers and chemicals for testing.

Examples The present invention will be verified with reference to the following examples. Unless otherwise specified, parts and percentages used are by weight. Fluorolink E10H-a PFPE polymer containing hydroxyl functional groups from Solvay, with a solid content of 100% by weight. Kayarad DPHA-a mixture of dipentaerythryl hexaacrylate and dipentaerythryl pentaacrylate from Nippon Kayaku chemical (Wuxi) Co., Ltd. , Hydroxyl value 40-50 mg KOH/g DMPA-Dimethylolpropionic acid DMEA-dimethylethanolamine from Shanghai Dibo Biotechnology Co., Ltd.

Example 1 Polyurethane acrylate dispersion prepared with PFPE diol (X1) Put isophorone diisocyanate (26.3 g), dibutyltin dilaurate (0.2 g), butylated hydroxytoluene (0.2 g) and butyl acetate (22.2 g) into the fourth part equipped with a stirrer and condenser Neck round bottom flask. Fluorolink E10H (2 g) was added to the mixture and heated to 60°C. The mixture was boiled at 60°C for 1 hour. Then Kayarad DPHA (165.76 g) was dropped into the mixture at 60°C over 2 hours and the mixture was boiled at 60°C for 1 hour. Then dimethylolpropionic acid (DMPA) (7.94 g) was added to the mixture at once and the temperature was increased to 80°C. The mixture is boiled at 80°C for 2 to 3 hours or more until the NCO groups have completely disappeared. After the NCO group could not be detected, the temperature was lowered to 60°C and 2-(dimethylamino)ethanol (DMEA) (4.75 g) was added to the mixture. The mixture was maintained at 60°C for another 1 hour, and then water (300 g) was added to the mixture at 60°C in 10 minutes while stirring at high speed to obtain an aqueous dispersion.

Example 2 Polyurethane acrylate prepared using X2 Step 1- Synthesis of intermediate X2 hexamethylene diisocyanate (8.4 g), dibutyltin dilaurate (0.1 g) and butyl acetate (25 g) Put it into a four-neck round bottom flask equipped with a stirrer and a condenser. Fluorolink E10H (84.9 g) and dimethylolpropionic acid (DMPA) (6.69 g) were added to the mixture immediately at 60°C. The mixture was then boiled at 60°C for 1 hour, and then the temperature was increased to 90°C and reacted for another 2 to 3 hours or longer until the NCO group could not be detected. After no NCO groups were detected, the temperature was lowered to 60°C and 2-(dimethylamino)ethanol (DMEA) (3.78 g) was added to the mixture. The mixture was kept at 60°C for another hour, then poured into a container and filled for the next step. The obtained polymer has Mn 912, Mw 1439, PD 1.58, and the solid content is 80% by weight as measured by GPC.

Step 2- Synthesis of polyurethane acrylic dispersion. Put hexamethylene diisocyanate (30.84 g), dibutyltin dilaurate (0.3 g), BHT (0.3 g) and butyl acetate (33.3 g) into it A four-neck round bottom flask equipped with a stirrer and condenser. The intermediate solution X2 (5 g) prepared in step 1 is added to the mixture and heated to 60°C. The mixture was boiled at 60°C for 1 hour. Then Kayarad DPHA (260 g) was dropped into the mixture at 60°C over 2 hours and the mixture was boiled at 60°C for 1 hour. Then dimethylolpropionic acid (DMPA) (12.3 g) was added to the mixture at once, and then the temperature was increased to 80°C. The mixture is kept at 80°C for 2 to 3 hours or more until the NCO group disappears completely. After no NCO groups were detected, the temperature was lowered to 60°C and 2-(dimethylamino)ethanol (DMEA) (7.35 g) was added to the mixture. The mixture was kept at 60°C for another 1 hour, and then water (450 g) was added within 10 minutes at 60°C while stirring at high speed to obtain an aqueous dispersion.

Example 3 Polyurethane acrylate prepared using X3-PFPE-modified partially blocked urethane acrylate. Step 1- Synthesis of intermediate X3 . Isophorone diisocyanate (12.08 g), dilaurel Dibutyl tin acid (0.1 g), butylated hydroxytoluene (0.1 g) and butyl acetate (25 g) were placed in a four-neck round bottom flask equipped with a stirrer and a condenser. At 60°C, Fluorolink E10H (46.22 g) was added dropwise to the mixture and the mixture was heated at 60°C for 1 hour. Then Kayarad DPHA (38.06 g) was dropped into the mixture at 60°C within 1 hour and the mixture was boiled at 60°C for another 1 hour. Then dimethylolpropionic acid (DMPA) (3.64 g) was added to the mixture at once and the temperature was increased to 80°C. The mixture is boiled at 80°C for 2 to 3 hours or more until the NCO groups have completely disappeared. After no NCO groups were detected, the temperature was lowered to 60°C and 2-(dimethylamino)ethanol (DMEA) (2.17 g) was added to the mixture. The mixture was kept at 60°C for another hour, then poured into a container and filled for the next step. The obtained polymer has Mn 1241, Mw 1642, PD 1.32, and the solid content is 80% by weight as measured by GPC.

Step 2- Synthesis of polyurethane acrylate dispersion. Combine hexamethylene diisocyanate (30.84 g), dibutyltin dilaurate (0.3 g), butylated hydroxytoluene (0.3 g) and butyl acetate ( 33.3 g) Put it into a four-neck round bottom flask equipped with a stirrer and a condenser. Intermediate solution 1 (8.15 g) from step 1 was added to the mixture and heated to 60°C. The mixture was heated at 60°C for 1 hour. Then Kayarad DPHA (256.89 g) was dropped into the mixture at 60°C over 2 hours and the mixture was boiled at 60°C for 1 hour. Then dimethylolpropionic acid (DMPA) (12.3 g) was immediately added to the mixture and the temperature was increased to 80°C. The mixture is heated at 80°C for 2 to 3 hours or more until the NCO group disappears completely. After no NCO groups were detected, the temperature was lowered to 60°C and 2-(dimethylamino)ethanol (DMEA) (7.35 g) was added to the mixture. The mixture was kept at 60°C for another 1 hour, and then water (450 g) was dropped in 10 minutes at 60°C while stirring at high speed to obtain an aqueous dispersion.

Example 4 Preparation of coating composition and coated substrate For evaluating the properties of the polyurethane acrylate synthesized in Examples 1 to 3, a coating composition was prepared according to Table 1. As the photoinitiator, Irgacure 184 and Irgacure TPO were used, both of which were purchased from BASF. As wetting additives, TEGO 4100 and TEGO 425, purchased from Evonik, were used. Table 1 Element Amount, g Polyurethane acrylate dispersion (solid content 40% by weight) 50 Photoinitiator (solid content 60% by weight) 2 Cosolvent* 1 Wetting additives 0.4 *Co-solvent——Propylene Glycol Monomethyl Ether

Spray the coating composition onto the PC/ABS panel and put it in an oven at 60°C for 8 to 10 minutes. After that, the panels are passed through the machine RW-UVAN301-30aks, where they are irradiated with UV light using a Hg lamp.

Example 5 Antifouling Test Using the chemicals listed in Table 2, the coated substrate obtained in Example 4 was subjected to an antifouling test. These chemicals are applied to the substrate, kept at room temperature for 1 hour and then wiped off. No discoloration or peeling of the coating was observed. Table 2 Pollutant Rating Lipstick (red) Grade A Coffee (Nescafe 3 in 1) Grade A Yellow mustard Grade A Water-soluble ink Grade A Crayons (black) Grade A Red wine (Beaujolais) Grade A Beer-Heineken Grade A Regular Coca-Cola Grade A Sunscreen (Nivea SPF15) Grade A Lotion (Nivea) Grade A Artificial sweat (pH 4.7, pH 8.7) Grade A

Ratings are provided according to the following scale: Grade A-no effect, grade B-slight surface changes and discoloration, grade C-coating shrinkage or softening, and grade D-coating blistering or deformation.

No difference was observed between the stain resistance of the coatings prepared based on the polyurethane acrylate dispersions prepared in Examples 1 to 3. They all accept the grade A rating for all chemicals, see Table 2.

As can be seen from the above table, the coating composition according to the present invention has excellent stain resistance to common chemicals.

The resistance of the coated substrates to more severe pollution was also tested. At 40°C, 90% RH, the chemicals from Table 3 were applied to the coated substrate as described above for 168 hours. After the test, remove the chemicals and clean the surface first with running tap water. If the contamination is visible, clean it with a soap solution, and if the contamination is still visible, clean it with isopropyl alcohol. table 3 Pollutant Rating Sunscreen, Banana Boat SPF 30 Grade A Dish soap, Ivory Grade A Magic Cleaner Grade A 409 cleaner Grade A Mustard, French's yellow Grade A Coca Cola Grade A 70% isopropanol Grade A Extra virgin olive oil Grade A Emulsion, Vaseline Intensive Care (Vaseline Intensive Care) Grade A Tomato sauce, Heinz Grade A acetone Grade A Artificial sweat Grade A Hand cream, Fruits & Passion Cucina Grade A Red lip balm, Maybelline Grade A Rouge, Maybelline Expert Wear Blush Beach Plum Grade A Mayonnaise, Kraft Grade A

No difference was observed between the stain resistance of the coatings prepared based on the polyurethane acrylate dispersions prepared in Examples 1 to 3. They all accept the grade A rating for all chemicals, see Table 3.

Example 6 Scratch Resistance Test The coated substrate obtained in Example 4 was subjected to 50 cycles of double rubbing with the chemicals listed in Table 4. Table 4 Chemicals Rating Simulated sweat-acid (pH 5.0) Level 5 Simulated sweat-alkaline (pH 8.8) Level 5 Engine oil Level 5 Lemon juice Level 5 Windex (ammonia) Level 5 Ethanol Level 5 100% virgin olive oil Level 5

After the test, visually inspect the processed panels and obtain grades 1 to 5: grade 5—no visible surface change, grade 4—slight change in surface gloss, grade 3—moderate deterioration/discoloration/contamination of the surface, and grade 2—severe surface Softening/pollution/peeling or deterioration, level 1—all the painted surface dissolves and exposes the substrate.

No difference was observed between the scratch resistance of coatings prepared based on the polyurethane acrylate dispersions prepared in Examples 1 to 3. They all accept a grade 5 rating for all chemicals, see Table 4.

Example 7 Comparative example In this example, a coating composition is prepared which contains a commercially available water-based UV curable resin mixed with polyurethane additives for easy cleaning properties. This is then compared with the coating composition according to the present invention prepared by "one-pot synthesis".

To prepare polyurethane additives, put isophorone diisocyanate (15.42 g), n-butyl acetate (17.6 g), dibutyl tin dilaurate (0.1 g) and butylated hydroxytoluene (0.1 g) into it A four-neck round bottom flask equipped with a stirrer and condenser. Fluorolink E10H (58.97 g) was dropped into the mixture at 60°C for 1 hour. The reaction mixture was heated at 60°C for half an hour. Then Kayarad DPHA (20.47 g) was dropped into the mixture at 80°C within half an hour and the mixture was boiled at 80°C for half an hour. Then dimethylolbutyric acid (DMBA) (5.14 g) was added to the mixture at 80°C and cooked at 80°C for 1 hour. Then the temperature was increased to 90°C and the reaction continued until no NCO groups were detected. The reaction mixture was cooled down to 60°C and DMEA (3.41 g) was added to the mixture and stirred at 60°C for another half an hour.

The resulting polyurethane has Mn 1106, Mw 4948, and PD 4.5. Before neutralization, the acid value of the polyurethane was 19.5 mg KOH/g; the OH value was 0 mg KOH/g.

Preparation of comparative coating composition The ingredients listed in Table 5 were used to prepare a comparative coating composition. table 5 Amount, g Olester RA7011 (solid content: 45%) 60 Polyurethane additive dispersion (solid content: 50% by weight) 0.24 Photoinitiator (solid content: 60% by weight) 2 D 0.3

Oleaster RA7011 is a commercially available water-based UV curable resin purchased from Mitsui Chemicals. The coating composition contains 0.4% by weight of polyurethane additives, which are prepared in the previous step and added as a 50% by weight aqueous dispersion. The coating composition is applied to a PC/ABS substrate and cured by exposure to ultraviolet light.

Use permanent markings with black ink to draw lines on the coated substrate.

Figure 1(a) shows a substrate coated with the comparative paint prepared in Example 7. Figure 1(b) shows a substrate coated with a coating according to the present invention, the coating containing any of the polyurethane acrylate dispersions prepared in Examples 1 to 3.

It can be seen that when fluorine-containing additives are used in the mixture with WB UV resin, the black ink does not shrink on Figure 1(a). In contrast, the black ink shrinks into beads on the surface of the coating according to the present invention. Therefore, the "one-pot synthesis" according to the present invention results in a coating with even better antifouling performance than a coating containing a mixture of resin and easy-to-clean additives.

Figure 1(a) shows a substrate coated with the comparative paint prepared in Example 7. Figure 1 (b) shows a substrate coated with the coating according to the present invention prepared in Example 4, the coating containing any of the polyurethane acrylate dispersions prepared in Examples 1 to 3.

Claims (14)

An aqueous dispersion containing a mixture of linear fluorinated and non-fluorinated polyurethane acrylates, which can be obtained by: a) The polyisocyanate A', the polyunsaturated OH-functional group-containing compound B', and the acid-functional group-containing polyol C'are reacted in the presence of intermediate X under the conditions of the urethane formation reaction, wherein the intermediate X is The OH functional group-containing (per)fluoropolyether (PFPE) derivative present in an amount of 0.1 to 10% by weight based on the total weight of the reaction mixture based on the solid weight, wherein no compound with a functionality of 3 or higher is used, b) adding the neutralizer D to the reaction product of step a) and dispersing in water, Among them, Intermediate X is selected from the list of the following components: i. Hydroxy-terminated (per)fluoropolyether, ii. The reaction product of PFPE diol with polyisocyanate A and polyol C containing acid functional groups under the conditions of urethane formation, and iii. The reaction product of PFPE diol with polyisocyanate A, polyunsaturated OH functional group-containing compound B and acid functional group-containing polyol C under urethane formation conditions. Such as the dispersion of claim 1, wherein the hydroxyl-terminated (per)fluoropolyether has the general structure HO-(CH ₂ CH ₂ O) _p -CH ₂ -CF ₂ -R _f -CF ₂ -CH ₂ -( OCH ₂ CH ₂ ) _q -OH where p and q are integers independently selected from 0 to 50, and R _f represents a perfluoropolyether structure (CF ₂ CF ₂ O) _n , (CF ₂ O) _m or (CF ₂ -CF ₂ -O) _n -(CF ₂ -O) _m is a difunctional group, and wherein n and m are integers independently selected from 1 to 100. The dispersion liquid of any one of claims 1 to 2, wherein the acid functional group-containing polyol C or C'is 2,2-dimethylolpropionic acid (DMPA) or 2,2-dimethylolbutanoic acid (DMBA). The dispersion liquid according to any one of claims 1 to 3, wherein the polyunsaturated compound B or B'is a monoOH functional group-containing (meth)acrylate monomer, more preferably dipentaerythritol pentaacrylate (DPPA). The dispersion of any one of claims 1 to 4, wherein the amount of intermediate X used in step (a) is 0.1 to 10% by weight based on the total weight of the reaction mixture. The dispersion liquid according to any one of claims 1 to 5, wherein the neutralizer D is a saturated tertiary amine. A water-based UV curable coating composition comprising the aqueous dispersion according to any one of claims 1 to 6. The coating composition according to claim 7, which further comprises at least one polymer different from the polyurethane acrylate according to any one of claims 1 to 6. The coating composition of claim 8, wherein the at least one polymer is poly(meth)acrylate. The coating composition according to any one of claims 7 to 9, which further comprises a photoinitiator. The coating composition according to any one of claims 7 to 10, which further comprises an organic solvent in an amount of less than 10% by weight based on the total weight of the coating composition. A method for coating a substrate, which comprises applying the coating composition according to any one of claims 7 to 11 to the substrate and curing the coating composition by means of UV radiation. A coated article comprising a substrate coated with the coating composition according to any one of claims 7 to 11. Such as the product of claim 13, wherein the substrate is selected from the group consisting of polycarbonate acrylonitrile butadiene styrene (PC/ABS), polycarbonate, polyacrylate, polyolefin, polyamide, poly Styrene, glass, wood, aluminum and aluminum alloys.

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