WO2024073457A1 - Water miscible fluorescent monomer as marking in a waterborne coating - Google Patents

Abstract

The present invention relates to a method for marking coating compositions comprising adding a water-miscible fluorescent monomer to the coating composition. The fluorescent monomers of the present invention are water miscible compounds corresponding to: (Formula (I)) where: R2 and R3 are independently C₁-C₄ linear or branched alkyl; R1 is selected from (meth)allyl, (meth)acryl, 2-hydroxy-3-(meth)allyloxypropyl, 1- hydroxy-3-(meth)allyloxypropyl, vinylbenzyl, 3-(meth)acrylamidopropyl, and 2- (meth)acryloyloxy ethyl, or alkyl; X is an anionic counter ion preferably selected from chloride, bromide, hydroxide, methosulphate, sulfate, sulfonate, carboxylate, phosphate, and phosphonate; and R4 is independently selected from H, hydroxy, alkoxy, aryloxy, arylalkoxy, alkylaryloxy, (meth)allyloxy, vinylbenzyloxy, heteroaryl, -NO₂, Ci-C_{4 alk}-0-(CHR5CH₂0-)_n, -CO₂H or a salt thereof, -SO₃H or a salt thereof, -PO₃H₂ or a salt thereof, -alkylene-C0₂H or a salt thereof, -alkylene-S0₃H or a salt thereof, and -alkylene-P0₃H₂ or a salt thereof.

Description

WATER MISCIBLE FLUORESCENT MONOMER AS MARKING IN A WATERBORNE COATING Technical Field The current disclosure pertains to water miscible fluorescent monomers which are suitable for marking in a waterborne coating. Background and Summary It is well known to tag petroleum fuels with "silent" markers so that the fuels can be identified for tax purposes, source of manufacture, brand identification and/or to prevent dilution adulteration. Such markers are added to the fuels at low levels, typically at levels of 100 ppm or well below, where they are not readily detectable with the naked eye. However, as it is necessary to be able to easily detect the presence of such markers, a simple chemical test must be available for their detection. A typical petroleum marker reacts readily with a reagent, such as an acid, a base, or in the case of markers described in U.S. Patent No.4,209,302, with acid and a diazotized reagent, to produce a chemical species which is both extractable in an aqueous medium and becomes highly colored through a chromophoric reaction. The markers in U.S. Patent No.4,209,302 have also found a non-fuel use as markers for asphalt additives, as described in U.S. Patent No.5,306,343. By use of such a marker, it can be determined whether a contractor is actually adding, and in appropriate amounts, the additive which adds substantial life to the asphalt, but which additive is relatively expensive. For similar reasons, it would be desirable to tag additives commonly used in waterborne or water-processable materials and compositions. Additives in the form of aqueous solutions, dispersions and emulsions, are often added to concrete to improve its water-resistance, strength and long-term durability. Hence, it would be desirable to have a tool or means to ensure that the specific additive is, in fact added to the concrete, in certain high liability end-use applications such as concrete structures of bridges or high-rise buildings. Likewise, similar issues exist in the paint industry. It would be desirable to have a simple and economic method for brand/manufacturer identification. Paint companies are known to pay- out large sums of money yearly in order to settle paint failure claims. In many cases, the paint manufacturer has no fool-proof method in identifying that it is its paint that has actually failed. Therefore, claims go uncontested and are settled strictly based on receipts which can be easily falsified. To avoid these issues, marking of the coating is a potential solution. Solvent based marker has been used in the prior art. Some marker compositions are integrated into the polymer requiring higher concentration and compatibility of marker into polymerization system. These polymers are not easy to detect and require isolation for detection. Several markers carry unwanted side effects such as toxicity and/or require a high dosage level. Other markers do not have a broad range of temperature or pH stability in coating formulation, and some can be removed from the marked compositions in process or in use. Accordingly, there is a need for new markers for use in the coatings industry, particularly ones which can be physically added to a coating formulation at any stage of the preparation of coating material, and which can be detected in the field without destroying the coating. The present invention addresses at least some of these needs. The instant invention proposes a water miscible fluorescent monomer to be physically added to a coating formulation at any stage of the preparation of coating material. The water miscible fluorescent monomers of the present invention can be of formula (I) below. preferably be either 4-methoxy-N-(3-N',N'- dimethylaminopropyl naphthalimide, vinylbenzyl chloride quaternary salt (CASRN # 371239- 11-1) or N,N-Dimethyl-N-[3-[N'-(4-methoxynaphthalimide)]]propyl-N-(2-hydrox y-3- allyloxy)propyl ammonium hydroxide (CASRN # 276878-97-8). (I)

where R2 and R3 are independently C₁-C₄ linear or branched alkyl, preferably C₁-C₂ alkyl, more preferably C₁ alkyl; and R1 is selected from (meth)allyl, (meth)acryl, 2-hydroxy-3-(meth)allyloxypropyl, 1- hydroxy-3-(meth)allyloxypropyl, vinylbenzyl, 3-(meth)acrylamidopropyl, and 2- (meth)acryloyloxy ethyl, or alkyl; and X is an anionic counter ion preferably selected from chloride, bromide, hydroxide, methosulphate, sulfate, sulfonate, carboxylate, phosphate, and phosphonate; and R4 is independently selected from H, hydroxy, alkoxy, aryloxy, arylalkoxy, alkylaryloxy, (meth)allyloxy, vinylbenzyloxy, heteroaryl, -NO₂, Ci- C_4alk-0-(CHR5CH₂0-)n, -C0₂H or a salt thereof, -S0₃H or a salt thereof, - PO₃H₂ or a salt thereof, -alkylene-C0₂H or a salt thereof, -alkylene-S0₃H or a salt thereof, and -alkylene-PO₃H₂ or a salt thereof. These additives enable qualitative in-situ detection of the marker using UV light. The additive shows no or minimal negative impact on finished coating formulation properties. The reflectance of the monomer is easily detectable using UV light in both, untinted and tinted, systems. Detailed Description of the Invention The embodiments of the present invention described below are not intended to be exhaustive or to limit the invention to the precise forms disclosed in the following detailed description. Rather, the embodiments are chosen and described so that others skilled in the art can appreciate and understand the principles and practices of the present invention. The term “about” used preceding any numerical value of the disclosure or appended claims allows some slight imprecision in that stated numerical value, which imprecision may either be understood in the art, or may result from methods of measuring to obtain such numerical values (e.g., such as with chemical or physical measurements), and any numerical value not preceded by the term “about” of the disclosure or appended claims may also be understood the same way. Methods and compositions of the disclosure described as “comprising” or “including” can include those recited step and compounds, respectively, and optionally can include other steps and components. If methods or compositions of the disclosure are described as “consisting of,” those methods or compositions have the recited steps or compounds but do not include steps or compounds that are not recited. The term “consisting essentially of” generally refers to compositions that include the recited compounds and may include other non-recited compounds, but in unsubstantial amounts. For example, such compositions can include one or more other non-recited components but not in an amount that is greater than about 1% (by weight), greater than about 0.5% (by weight), or greater than about 0.1% (by weight) of the total composition. In a composition “consisting of” the recited components there is no other measurable amount of component other than the recited component, or a method “consisting” of certain steps includes no other steps than those ones recited. The present invention relates to a method for marking coating compositions comprising adding a water-miscible fluorescent monomer to the coating composition. The fluorescent monomers of the present invention are water miscible. By “water-miscible” it is meant that the compound readily mixes with water at room temperature without forming separate layers. By fluorescent, it is meant that the compound absorbs light from a UV source at a given wavelength and then emits radiation at a different wavelength, preferably one in the visible range. The water miscible fluorescent monomers should be stable at a temperature range of from -20° to 50°C preferably from -10°C to 40°C. The water miscible fluorescent monomers should also be stable at a pH range of from 7 to 11, preferably from 8 to 9.5. By “stable” it is meant that the monomers is part of formulation and does not separate and/or result in layering during formulation stability studies. The water miscible fluorescent monomers of the present correspond to formula (I) below. (I)

where R2 and R3 are independently C₁-C₄ linear or branched alkyl, preferably C₁-C₂ alkyl, more preferably C1 alkyl; and R1 is selected from (meth)allyl, (meth)acryl, 2-hydroxy-3-(meth)allyloxypropyl, 1- hydroxy-3-(meth)allyloxypropyl, vinylbenzyl, 3-(meth)acrylamidopropyl, and 2- (meth)acryloyloxy ethyl, or alkyl; and X is an anionic counter ion preferably selected from chloride, bromide, hydroxide, methosulphate, sulfate, sulfonate, carboxylate, phosphate, and phosphonate; and R4 is independently selected from H, hydroxy, alkoxy, aryloxy, arylalkoxy, alkylaryloxy, (meth)allyloxy, vinylbenzyloxy, heteroaryl, -NO₂, Ci- C_4alk-0-(CHR5CH₂0-)_n, -C0₂H or a salt thereof, -S0₃H or a salt thereof, - PO₃H₂ or a salt thereof, -alkylene-C0₂H or a salt thereof, -alkylene-S0₃H or a salt thereof, and -alkylene- PO₃H₂ or a salt thereof. Preferably the water miscible fluorescent monomers of the present invention are either 4- methoxy-N-(3-N',N'-dimethylaminopropyl naphthalimide, vinylbenzyl chloride quaternary salt (CASRN # 371239-11-1) or N,N-Dimethyl-N-[3-[N'-(4-methoxynaphthalimide)]]propyl-N-(2- hydrox y-3-allyloxy)propyl ammonium hydroxide (CASRN # 276878-97-8). Preferably the water-miscible fluorescent monomer is added in an amount of from 5 ppm to 200 ppm by weight of the coating composition, more preferably in a range of from at least 10 ppm, 25 ppm, 50 ppm or even 75 ppm up to 175 ppm, 150, ppm or even 125 ppm with about 100 ppm being most preferred. The fluorescent monomer markers of the present invention can be added to any paint/coating which is compatible with water. Such water based interior/exterior coatings are well known in the art. The fluorescent monomer markers of the present invention can be added at any stage of the preparation of the coating/paint, and can be added alone or with one or more other components of the coating/paint. The fluorescent monomers of the present invention should not substantially alter the properties of the coating except for the fluorescence. For example, the whiteness and the yellowness of the coating (as determined using ASTM E 313), the gloss/sheen (as determined using ASTM D523, opacity, at a 3 mil drawdown (as determined using ASTM D 2805), the viscosity (as determined using a Stormer viscometer and ASTM D562) should all be within 5%, 4%, 3%, 2%, 1% of the values obtained from similar formulations except for the absence of the fluorescent markers. Preferably these properties are unchanged by the presence of the fluorescent marker. In practice, the fluorescent markers of the present invention are added to the paint/coating, and then coating is then applied to a surface in any manner generally known in the art. Once applied the marker can be detected by shining a UV light source on the surface of the coating to determine if the expected fluorescence is observed. It is believed that the strength of the fluorescence can be measured by methods known in the art (such as by using a spectrometer) and that such strength can be correlated to the amount of fluorescent monomer present. In that way, dilution of the coating could be detected. Examples The process of the current invention is demonstrated in the following examples. A low pigment volume concentration (PVC) and a Mid PVC formulation coating were used for the evaluation. These coating made use of the materials: Table 1

The contents of the low PVC Paint formulation (Table 2) and the Mid Paint Formulation (Table 3) for the inventive and comparative examples are as follows: Table 2 Low PV Paint formulation

Table 3 Mid PVC Paint formulation

The procedure for making the low PVC paint formulation is as follows. To an amount of water (9.85 Wt.%) in Dispermat mixing equipment, DOWSIL™ 8590 (0.05 Wt.%) is slowly added with continuous stirring at 400 – 500 RPM. Add KATHON® LXE (0.10 Wt.%); ROCIMA® 363 (0.30 Wt.%), OROTAN™ 731A (1.00 Wt.%) and ECOSURF™ EH 9 (0.30 Wt%) step wise with continuous stirring. After 15 min, add TiO2 (R902) (18.00 Wt.%) and stir at 1000 RPM. After 10 min add Omya carb (10.00 Wt.%) and adjust the speed to 1500 - 1700 RPM. Mill base is prepared at high speed for 45 mins at 20m/sec for paint dispersion. Once the dispersion is complete the paint is then let down with addition of water (3.65wt%). Add Propylene glycol (2.00 Wt.%) and pure Acrylic Binder PRIMAL™ AC 369S (38.00 Wt.%) and ROPAQUE™ Ultra E (12.00 Wt.%) and stir 700 RPM. Add defoamer DOWSIL™ 8590 (0.05 Wt.%). Add mill base to the thickener solution with stirring at 700 RPM. Add Coalescing additive [UCAR™ Filmer IBT /TEXANOL™] (1.00 Wt.%). Add thickener [ACRYSOL™ RM 2020 NPR] (1.00 Wt%) and ACRYSOL™ RM 825 (0.5 Wt.%) and adjust viscosity as desired with remaining water (2.00 Wt.%). Add neutralizing agent solution to adjust pH (8.5 - 9.5) and obtain final paint composition. Add fluorescent monomer to the finished formulation, and allow the final formulation to mix for an additional 10 to 15 minutes. The procedure for making the mid PVC paint formulation is as follows. To an amount of water (17.85 Wt.%) in Dispermat mixing equipment, DOWSIL™ 8590 (0.05 Wt.%) is slowly added with continuous stirring at 400 – 500 RPM. Add KATHON® LXE (0.20 Wt.%); ROCIMA® 363 (1.00 Wt.%), OROTAN™ 1288 (1.00 Wt.%), pine oil (0.30 Wt.%), TERGITOL™ 15 S 40 (70%) (0.40 Wt.%) step wise, add slowly NATRASOL™ 250 HBR (0.20 Wt.%), UCAR™ MF 90 (0.20 Wt.%) with continuous stirring. After 15 min, Add TiO2 (R902) (15.00 Wt.%) with stirring speed at 1000 RPM, after 10 min add calcite – 4.00 Wt.%, china clay (10.00 Wt.%) and Talc (13.50 Wt.%) and speed was to 1500 - 1700 RPM. Mill base is prepared at high speed for 45 mins at 20m/sec for paint dispersion. Once the dispersion is complete the paint is then let down with additional water (5.95 wt %). Add Diethylene glycol (1.00 Wt.%) and Styrene acrylic Binder PRIMAL™ AS 511 (20.00 Wt.%) and ROPAQUE™ Ultra E (5.00 Wt.% ) step wise with stirring at 700 RPM. Add defoamer DOWSIL™ 8590 (0.05 Wt.%). Add mill base to the thickener solution with stirring at 700 RPM. Add Coalescing additive (UCAR™ Filmer IBT / TEXANOL® (1.50 Wt.%) and thickener ACRYSOL™ DR 110 (0.80 Wt.%) and adjust viscosity to the right KU viscosity as desired with remaining water (2.00 Wt.%) and obtain final paint composition. Add Fluorescent monomer to finished formulation and allow the final formulation to mix for an additional 10 to 15 minutes. These formulations were then tested for the properties shown in the tables: Table 4 Low PVC Formulation

Table 5 Mid PVC Formulation

These formulations shown in Tables 4 and 5 were allowed to age for 30 days at a temperature of 55°C and then the properties were re-measured as shown in Table 6 and 7 respectively

Table 6 Low PVC formulation after heat aging

Table 7 Mid PVC formulation after heat aging

Based on the lab scale evaluation of finished paint prepared without and with the proposed water miscible fluorescent monomer, it can be seen that the fluorescent monomer is stable under high sheer mixing and does not get separated out. Finished paint does not have any specific change in its properties during wet stage, cured film and the formulation is stable under accelerated heat age study and does not interfere with required optical properties and washability. The intent of the present invention is to ensure easy detection of the fluorescent monomer molecule without any extraction, using a UV lamp/torch. The following pictorial representation demonstrates a qualitative representation of the evaluation process as summarized in Table 8, where the number of “+” signs indicating the relative fluorescence strength compared to the control, and “+/=” indicating a marginal improvement, “=” and “=/-” indicating more or less similar with no real differentiation.: In visible light In UV light

In visible light In UV light

Pictorial representation of monomer dosage ( 100 ppm to 0 ppm) in visible light

Pictorial representation of monomer dosage ( 100 ppm to 0 ppm) in UV light exposure

Table 8 -Reflectance Strength rating

In visible light In UV light

Claims

CLAIMS: 1. A method for marking a paint or coating comprising adding a water miscible fluorescent monomer to the paint or coating and then exposing the paint or coating to an ultraviolet light source and observing whether the paint or coating exhibits fluorescence. 2. The method of claim 1 where the paint or coating is applied to a substrate and then is exposed to the ultraviolet light source. 3. The method of claim 1 wherein the water miscible fluorescent monomers correspond to

where: R2 and R3 are independently C₁-C₄ linear or branched alkyl; R1 is selected from (meth)allyl, (meth)acryl,

2-hydroxy-3-(meth)allyloxypropyl, 1- hydroxy-3-(meth)allyloxypropyl, vinylbenzyl,

3-(meth)acrylamidopropyl, and 2- (meth)acryloyloxy ethyl, or alkyl; X is an anionic counter ion preferably selected from chloride, bromide, hydroxide, methosulphate, sulfate, sulfonate, carboxylate, phosphate, and phosphonate; and R4 is independently selected from H, hydroxy, alkoxy, aryloxy, arylalkoxy, alkylaryloxy, (meth)allyloxy, vinylbenzyloxy, heteroaryl, -NO₂, Ci-C_4alk-0-(CHR5CH₂0-)n, -C0₂H or a salt thereof, -SO₃H or a salt thereof, -PO₃H₂ or a salt thereof, -alkylene-C0₂H or a salt thereof, - alkylene-SO₃H or a salt thereof, and -alkylene-PO₃H₂ or a salt thereof.

4. The method of claim 3 wherein the water miscible fluorescent monomer is selected from the group consisting of 4-methoxy-N-(3-N',N'-dimethylaminopropyl naphthalimide, vinylbenzyl chloride quaternary salt or N,N-Dimethyl-N-[3-[N'-(4- methoxynaphthalimide)]]propyl-N-(2-hydrox y-3-allyloxy)propyl ammonium hydroxide.

5. The method of claim 3 where R2 and R3 are independently a C₁-C₂ alkyl.

6. The method of claim 1 wherein the water miscible fluorescent monomer is added in a range of from 10 ppm to 200 ppm by weight.