WO2024064581A1 - Microbe resistant acrylic latex composition - Google Patents

Microbe resistant acrylic latex composition Download PDF

Info

Publication number
WO2024064581A1
WO2024064581A1 PCT/US2023/074314 US2023074314W WO2024064581A1 WO 2024064581 A1 WO2024064581 A1 WO 2024064581A1 US 2023074314 W US2023074314 W US 2023074314W WO 2024064581 A1 WO2024064581 A1 WO 2024064581A1
Authority
WO
WIPO (PCT)
Prior art keywords
composition
ppm
hydroperoxide
range
cio
Prior art date
Application number
PCT/US2023/074314
Other languages
French (fr)
Inventor
Arnold S. Brownell
Tara L. CONLEY
Erica A. FRANKEL
Benjamin REINER
Original Assignee
Rohm And Haas Company
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Rohm And Haas Company filed Critical Rohm And Haas Company
Publication of WO2024064581A1 publication Critical patent/WO2024064581A1/en

Links

Classifications

    • A—HUMAN NECESSITIES
    • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
    • A01N—PRESERVATION OF BODIES OF HUMANS OR ANIMALS OR PLANTS OR PARTS THEREOF; BIOCIDES, e.g. AS DISINFECTANTS, AS PESTICIDES OR AS HERBICIDES; PEST REPELLANTS OR ATTRACTANTS; PLANT GROWTH REGULATORS
    • A01N25/00—Biocides, pest repellants or attractants, or plant growth regulators, characterised by their forms, or by their non-active ingredients or by their methods of application, e.g. seed treatment or sequential application; Substances for reducing the noxious effect of the active ingredients to organisms other than pests
    • A01N25/02—Biocides, pest repellants or attractants, or plant growth regulators, characterised by their forms, or by their non-active ingredients or by their methods of application, e.g. seed treatment or sequential application; Substances for reducing the noxious effect of the active ingredients to organisms other than pests containing liquids as carriers, diluents or solvents
    • A01N25/04—Dispersions, emulsions, suspoemulsions, suspension concentrates or gels
    • A—HUMAN NECESSITIES
    • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
    • A01N—PRESERVATION OF BODIES OF HUMANS OR ANIMALS OR PLANTS OR PARTS THEREOF; BIOCIDES, e.g. AS DISINFECTANTS, AS PESTICIDES OR AS HERBICIDES; PEST REPELLANTS OR ATTRACTANTS; PLANT GROWTH REGULATORS
    • A01N25/00—Biocides, pest repellants or attractants, or plant growth regulators, characterised by their forms, or by their non-active ingredients or by their methods of application, e.g. seed treatment or sequential application; Substances for reducing the noxious effect of the active ingredients to organisms other than pests
    • A01N25/26—Biocides, pest repellants or attractants, or plant growth regulators, characterised by their forms, or by their non-active ingredients or by their methods of application, e.g. seed treatment or sequential application; Substances for reducing the noxious effect of the active ingredients to organisms other than pests in coated particulate form
    • A01N25/28—Microcapsules or nanocapsules
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
    • C09D5/02—Emulsion paints including aerosols
    • C09D5/024—Emulsion paints including aerosols characterised by the additives
    • C09D5/025—Preservatives, e.g. antimicrobial agents
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
    • C09D7/40—Additives
    • C09D7/60—Additives non-macromolecular
    • C09D7/63—Additives non-macromolecular organic
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K5/00—Use of organic ingredients
    • C08K5/04—Oxygen-containing compounds
    • C08K5/14—Peroxides

Definitions

  • the present invention relates to an acrylic latex composition that is resistant to microbial growth even in the absence of a biocide.
  • Aqueous dispersions of polymer particles (i.e., latexes) used in the coatings industry are preserved with antimicrobial agents to inhibit the formation and growth of biological organisms such as bacteria, yeast, and mold while in storage. Inhibition of these organisms prevents product degradation and spoilage, as well as off-gassing of volatile products and consequent pressure build-up in closed containment. Preservation is therefore essential for reasons of health, safety, and performance.
  • In-can preservatives such as isothiazolinones are facing intense regulatory scrutiny for their real or perceived adverse impact on health, safety, and the environment; in fact, an outright ban of these biocides in many parts of the world appears in the offing. Inasmuch as the development of new biocides is unlikely for reasons of cost and a widespread perception, justified or not, of their inherent dangers, a need exists to supplant biocides with alternative non-biocidal preservatives that are safer and more sustainable.
  • EP 3 456 787 Bl discloses a water-borne coating formulation adjusted to a pH in the range of 10 to 12.5. While ostensibly effective, these very high pH formulations create additional safety and health concerns that render this approach impractical. Other non-traditional approaches such as the addition of silver or zinc ions may adversely affect the properties of the paint and face regulatory scrutiny as well. For these reasons, other safer and more sustainable approaches for preserving paints, and materials that are used in paints, are needed.
  • the present invention addresses a need in the art by providing, in one aspect, a composition
  • a composition comprising a) an aqueous dispersion of acrylic-based polymer particles having a z-average particle size in the range of from 50 to 500 nm; and b) a C4-Cio-alkyl hydroperoxide having a concentration in the range of from 125 ppm to 2500 ppm, based on the weight of the composition.
  • composition of the present invention provides a latex that is resistant to microbial growth even in the absence of a biocide.
  • the present invention is a composition
  • a composition comprising a) an aqueous dispersion of acrylic-based polymer particles having a z-average particle size in the range of from 50 to 500 nm; and b) a C4-Cio-alkyl hydroperoxide having a concentration in the range of from 125 ppm to 2500 ppm, based on the weight of the composition.
  • the aqueous dispersion of acrylate-based polymer particles is advantageously prepared by contacting an acrylate monomer, a methacrylate monomer, and an acid monomer under emulsion polymerization conditions.
  • the resulting dispersion which contains structural units of the acrylate monomer, the methacrylate monomer, and the acid monomer, as well as residual unreacted monomer, is then contacted with a reductant such as isoascorbic acid or 2-hydroxy-2- sulfinatoacetic acid disodium salt, and a t-C4-Cio-alkyl hydroperoxide to chase residual monomer to acceptable levels.
  • a reductant such as isoascorbic acid or 2-hydroxy-2- sulfinatoacetic acid disodium salt
  • a t-C4-Cio-alkyl hydroperoxide to chase residual monomer to acceptable levels.
  • the /-CT-Cio-alkyl hydroperoxide is /-but
  • an acrylate monomer As used herein, the terms “an acrylate monomer,” “a methacrylate monomer,” and “an acid monomer” refer to one or more of acrylate, methacrylate, or acid monomers.
  • acrylic -based means that at least 70, preferably at least 80, and more preferably at least 90 weight percent of the monomers used to prepare the aqueous dispersion of acrylate-based polymer particles are acrylate, methacrylate, and acid monomers.
  • structural unit of a named monomer refers to the remnant of the monomer after polymerization.
  • a structural unit of methyl methacrylate (MMA) is as illustrated: structural unit of methyl methacrylate where the dotted lines represent the points of attachment of the structural unit to the polymer backbone.
  • Suitable acrylate monomers include Ci-Cio-acrylates such as ethyl acrylate, -butyl acrylate, t-butyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, 2-octyl acrylate, and 2-propylheptyl acrylate.
  • suitable methacrylate monomers include methyl methacrylate, ethyl methacrylate, /t-butyl methacrylate, t-butyl methacrylate, and ureido methacrylate.
  • Methyl methacrylate is a preferred methacrylate monomer; ethyl acrylate, n-butyl acrylate, and 2-ethylhexyl acrylate are preferred acrylate monomers.
  • the polymer particles preferably comprise from 70, or from 80, or from 90 weight percent, to 99 weight percent structural units of acrylate and methacrylate monomers based on the weight of polymer particles.
  • suitable acid monomers include carboxylic acid monomers and salts thereof, such as acrylic acid, methacrylic acid, and itaconic acid, and salts thereof; phosphorus acid monomers such and salts thereof such as phosphoethyl methacrylate and salts thereof; and sulfonic acid monomers and salts thereof such as 2-acrylamido-2-methyl-l-propanesulfonic acid and salts thereof; vinyl sulfonic acid and salts thereof; sodium 4-vinylbenzene sulfonate; and 2-propene- 1-sulfonic acid and salts thereof.
  • carboxylic acid monomers and salts thereof such as acrylic acid, methacrylic acid, and itaconic acid, and salts thereof
  • phosphorus acid monomers such and salts thereof such as phosphoethyl methacrylate and salts thereof
  • sulfonic acid monomers and salts thereof such as 2-acrylamido-2-methyl-l-propanesulfonic acid and salts thereof
  • Sodium 4-vinylbenzene sulfonate (also known as sodium styrene sulfonate or SSS) is a preferred sulfonate.
  • the polymer particles preferably comprise from 0.1 to 10 weight percent structural units of one or more acid monomers, based on the weight of the polymer particles.
  • the z-average particle size of the polymer particles as measured using dynamic light scattering is in the range of from 50 nm or from 80 nm, to 500 nm or to 300 nm or to 200 nm.
  • the mole-to-mole ratio of the t-C4-Cw-alkyl hydroperoxide to the reductant in the chase step is in the range of from 1:1 or from 3:1 or from 3.5: 1 or from 4.5:1 or from 5.5: 1 or from 6.5: 1 or from 7.0: 1, to 50:1 or to 30:1 or to 20: 1 or to 15: 1 or to 10:1.
  • the efficiency of this redox system can be controlled by a number of factors including the optional addition of a) a catalytic amount of a redox reaction catalyzing metal salt such as a salt of iron (II) such as FeSC , copper, manganese, vanadium, silver, platinum, nickel, chromium, palladium, or cobalt, or combinations thereof; b) addition of a chelating agent for the metal salt; c) adjustment of temperature; and d) adjustment of pH.
  • a catalytic amount of a redox reaction catalyzing metal salt such as a salt of iron (II) such as FeSC , copper, manganese, vanadium, silver, platinum, nickel, chromium, palladium, or cobalt, or combinations thereof
  • a chelating agent for the metal salt such as a salt of iron (II) such as FeSC , copper, manganese, vanadium, silver, platinum, nickel, chromium, palladium, or cobal
  • the r-Cr-Cio-alkyl hydroperoxide and reductant may be contacted with the aqueous dispersion of polymer particles in a single stage or in multiple stages using the same or different mole-to-mole ratios in each stage, provided the mole-to-mole ratio of the total amount of /-Cr-Cio-alkyl hydroperoxide added to the total amount of reductant added over multiple steps is in the prescribed range.
  • the resultant aqueous dispersion of polymer particles is preferably neutralized to a pH in the range of from 7.5 or from 8.0 or from 8.5 or from 8.8, to 10.0 or to 9.5 or to 9.2.
  • the resultant composition comprises from 125 ppm or from 150 ppm or from 175 ppm or from 225 ppm or from 275 ppm or from 350 ppm, to 2500 ppm or to 1250 ppm or to 1500 ppm of FCr-Cio-alkyl hydroperoxide and preferably less than 1000 ppm, more preferably less than 500 ppm of residual monomer.
  • concentration of the z-C4-C -alkyl hydroperoxide in the composition is determined using NMR spectroscopy as detailed in the experimental section.
  • the present invention is a method comprising the steps of: a) contacting, under emulsion polymerization conditions, monomers comprising an acrylate monomer, a methacrylate monomer, and an acid monomer to form an aqueous dispersion of acrylic-based polymer particles and residual monomers; b) contacting the dispersion of the acrylic-based polymer particles with a reductant and a t-Cr-Cio-alkyl hydroperoxide to reduce the concentration of residual monomers in the aqueous dispersion to less than 1000 ppm of residual monomers; wherein the mole-to-mole ratio of the t-C4-Cio-alkyl hydroperoxide to reductant is in the range of from 1:1 to 50:1.
  • composition of the present invention has been found to be resistant to the growth of mold, bacteria, and yeast under heat age conditions. Examples
  • a 10-mL polycarbonate tube was charged with 3.0 mL of a latex sample, 3.0 mL of Milli-Q water, and centrifuged at 100,000 rpm for 15 min. The resulting clear supernatant was decanted and transferred into a 5 -mm NMR tube.
  • a flame-sealed capillary tube filled with an external standard (5.00 wt% d4-sodium trimethylsilylpropionate in D2O) was added to the NMR tube. Careful attention was paid to proper alignment of the external standard within the NMR tube.
  • NMR spectra were obtained using the Bruker A VANCE III 600 spectrometer equipped with a 5-mm BroadBand CryoProbe.
  • Spectra were referenced to the external standard at 0.0 ppm on the trimethylsilyl chemical shift scale.
  • the purity of the resonances ascribed to hydroperoxides were unambiguously confirmed with a 'H- 13 C heteronuclear multiple bond coherence (HMBC) experiment using the hmbcgplpndqf pulse sequence.
  • SSS oligomer content was calculated by comparing the normalized integrations of peaks resonating around 7 ppm and the peak for the external standard at 0.0 ppm. Integral normalization was estimated by using a diffusion-ordered spectroscopy (DOSY) experiment using the ledbpgp2s pulse sequence to determine the weighted average mass of the SSS oligomers.
  • DOSY diffusion-ordered spectroscopy
  • Samples were tested for microbial resistance “as-is” (not heat-aged) as well as after being subjected to 50 °C for four-weeks (heat-aged).
  • a 10-g aliquot was taken from each sample and inoculated three times at 7-d intervals with 10 6 -10 7 colony forming units per milliliter of sample (CFU/mL) of a standard pool of bacteria, yeasts, and molds obtained from American Type Culture Collection (ATCC) that are common contaminants in coatings.
  • CFU/mL colony forming units per milliliter of sample
  • ATCC American Type Culture Collection
  • Samples were plated 1 d and 7 d after each microbial challenge onto trypticase soy agar (TSA) and potato dextrose agar (PDA) plates. All agar plates were checked daily up to 7 d after plating to determine the number of microorganisms surviving in the test samples. Between checks, the agar plates were stored in incubators at 30 °C for TSA plates and at 25 °C for PDA plates. The extent of microbial contamination was established by counting the colonies, where the rating score was determined from the number of microbial colonies observed on the agar plates. Reported results come from day 7 readings, and are summarized for both the “as-is” and heat-aged samples.
  • B bacteria
  • Y yeast
  • M mold.
  • a 3B describes a plate with 3 rating score for bacteria
  • Tr Y(l) describes a plate with trace yeast (1 colony on plate).
  • Table 1 illustrates the rating system used to estimate the level of microbial contamination on streak plates. Colonies refers to the number of colonies on the plate.
  • a monomer emulsion was prepared by mixing deionized water (800 g), sodium lauryl sulfate (16.59 g, 28% active), zi-butyl acrylate (1016.58 g), methyl methacrylate (889.53 g), ureido methacrylate (39.1 g, 50% active), methacrylic acid (19.55 g), and sodium 4-vinylbenzene sulfonate (10.87 g, 90% active).
  • a portion of the monomer emulsion (58.8 g) was then added to the flask, quickly followed by the addition of an aqueous solution of ammonium persulfate (6.8 g) dissolved in deionized water (20 g), followed by a rinse of deionized water (5 g). After stirring for 5 min, the remainder of the monomer emulsion and a solution containing ammonium persulfate (1.04 g) dissolved in deionized water (92 g) were each added separately to the flask over a total period of 65 min. The contents of the flask were maintained at 87 °C during the addition of monomer emulsion.
  • the vessel containing residual monomer emulsion was rinsed with deionized water (25 g), which was then added to the flask.
  • deionized water 25 g
  • the contents of the flask were cooled to 75 °C and an aqueous solution of FeSCU (20.1 g, 0.1% solids) and an aqueous solution of the tetrasodium salt of EDTA (2 g, 1% solids) were added to the kettle.
  • a catalyst / activator pair of a) r-amyl hydroperoxide (r-AHP, 1.27 g, 85% active) dispersed in 40 g of deionized water, and b) isoascorbic acid (IAA, 0.75 g) dissolved in 40 g of deionized water were then added linearly and separately to the flask over 20 min. The contents of the flask were maintained at 75 °C during the addition of the catalyst / activator pair.
  • the polymer was then neutralized to pH ⁇ 9.0 with an aqueous solution of ammonium hydroxide and deionized water.
  • the z-average particle size was found to be 116 nm using a Brookhaven BI-90 Plus Particle Size Analyzer; the measured solids was 50.3%.
  • Comparative Example 1 The method of Comparative Example 1 was repeated except that the amount by weight of /- AHP added after the flask was cooled to 75 °C was increased 2-fold (Example 1), 3-fold (Example 2), 4-fold (Example 2), and 5-fold (Example 4).
  • Table 2 illustrates the relative concentrations of t-AHP added with respect to Comparative Example 1 , as well as the concentrations of t-AHP and /-amyl hydroperoxide (t-AmOH) measured in the final neutralized dispersion.
  • Table 2 Relative Concentrations of t-AHP Table 3 illustrates the heat-age challenge test results for the samples.

Landscapes

  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Wood Science & Technology (AREA)
  • Health & Medical Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • General Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Plant Pathology (AREA)
  • Pest Control & Pesticides (AREA)
  • Agronomy & Crop Science (AREA)
  • Dentistry (AREA)
  • Dispersion Chemistry (AREA)
  • Zoology (AREA)
  • Environmental Sciences (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)

Abstract

The present invention relates to a composition comprising a) an aqueous dispersion of polymer particles having a z-average particle size as measured using dynamic light scattering in the range of from 50 nm or from 80 nm, to 500 nm or to 300 nm or to 200 nm; and b) a C4-C10-alkyl hydroperoxide having a concentration in the range of from 250 ppm to 5000 ppm, based on the weight of the composition. The composition of the present invention provides a latex that is resistant to microbial growth even in the absence of a biocide.

Description

Microbe Resistant Acrylic Latex Composition
Background of the Invention
The present invention relates to an acrylic latex composition that is resistant to microbial growth even in the absence of a biocide.
Aqueous dispersions of polymer particles (i.e., latexes) used in the coatings industry are preserved with antimicrobial agents to inhibit the formation and growth of biological organisms such as bacteria, yeast, and mold while in storage. Inhibition of these organisms prevents product degradation and spoilage, as well as off-gassing of volatile products and consequent pressure build-up in closed containment. Preservation is therefore essential for reasons of health, safety, and performance.
In-can preservatives such as isothiazolinones are facing intense regulatory scrutiny for their real or perceived adverse impact on health, safety, and the environment; in fact, an outright ban of these biocides in many parts of the world appears in the offing. Inasmuch as the development of new biocides is unlikely for reasons of cost and a widespread perception, justified or not, of their inherent dangers, a need exists to supplant biocides with alternative non-biocidal preservatives that are safer and more sustainable.
A recent example of a non-biocidal approach for preserving paints against microbial contamination can be found in EP 3 456 787 Bl, which discloses a water-borne coating formulation adjusted to a pH in the range of 10 to 12.5. While ostensibly effective, these very high pH formulations create additional safety and health concerns that render this approach impractical. Other non-traditional approaches such as the addition of silver or zinc ions may adversely affect the properties of the paint and face regulatory scrutiny as well. For these reasons, other safer and more sustainable approaches for preserving paints, and materials that are used in paints, are needed.
Summary of the Invention
The present invention addresses a need in the art by providing, in one aspect, a composition comprising a) an aqueous dispersion of acrylic-based polymer particles having a z-average particle size in the range of from 50 to 500 nm; and b) a C4-Cio-alkyl hydroperoxide having a concentration in the range of from 125 ppm to 2500 ppm, based on the weight of the composition.
The composition of the present invention provides a latex that is resistant to microbial growth even in the absence of a biocide.
Detailed Description of the Invention
In a first aspect, the present invention is a composition comprising a) an aqueous dispersion of acrylic-based polymer particles having a z-average particle size in the range of from 50 to 500 nm; and b) a C4-Cio-alkyl hydroperoxide having a concentration in the range of from 125 ppm to 2500 ppm, based on the weight of the composition.
The aqueous dispersion of acrylate-based polymer particles is advantageously prepared by contacting an acrylate monomer, a methacrylate monomer, and an acid monomer under emulsion polymerization conditions. The resulting dispersion, which contains structural units of the acrylate monomer, the methacrylate monomer, and the acid monomer, as well as residual unreacted monomer, is then contacted with a reductant such as isoascorbic acid or 2-hydroxy-2- sulfinatoacetic acid disodium salt, and a t-C4-Cio-alkyl hydroperoxide to chase residual monomer to acceptable levels. Preferably, the /-CT-Cio-alkyl hydroperoxide is /-butyl hydroperoxide (r-BHP) or /-amyl hydroperoxide (/-AHP) or a combination thereof.
As used herein, the terms “an acrylate monomer,” “a methacrylate monomer,” and “an acid monomer” refer to one or more of acrylate, methacrylate, or acid monomers. As used herein, “acrylic -based” means that at least 70, preferably at least 80, and more preferably at least 90 weight percent of the monomers used to prepare the aqueous dispersion of acrylate-based polymer particles are acrylate, methacrylate, and acid monomers.
As used herein, “structural unit” of a named monomer refers to the remnant of the monomer after polymerization. For example, a structural unit of methyl methacrylate (MMA) is as illustrated:
Figure imgf000004_0001
structural unit of methyl methacrylate where the dotted lines represent the points of attachment of the structural unit to the polymer backbone.
Examples of suitable acrylate monomers include Ci-Cio-acrylates such as ethyl acrylate, -butyl acrylate, t-butyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, 2-octyl acrylate, and 2-propylheptyl acrylate. Examples of suitable methacrylate monomers include methyl methacrylate, ethyl methacrylate, /t-butyl methacrylate, t-butyl methacrylate, and ureido methacrylate. Methyl methacrylate is a preferred methacrylate monomer; ethyl acrylate, n-butyl acrylate, and 2-ethylhexyl acrylate are preferred acrylate monomers. The polymer particles preferably comprise from 70, or from 80, or from 90 weight percent, to 99 weight percent structural units of acrylate and methacrylate monomers based on the weight of polymer particles.
Examples of suitable acid monomers include carboxylic acid monomers and salts thereof, such as acrylic acid, methacrylic acid, and itaconic acid, and salts thereof; phosphorus acid monomers such and salts thereof such as phosphoethyl methacrylate and salts thereof; and sulfonic acid monomers and salts thereof such as 2-acrylamido-2-methyl-l-propanesulfonic acid and salts thereof; vinyl sulfonic acid and salts thereof; sodium 4-vinylbenzene sulfonate; and 2-propene- 1-sulfonic acid and salts thereof. Sodium 4-vinylbenzene sulfonate (also known as sodium styrene sulfonate or SSS) is a preferred sulfonate. The polymer particles preferably comprise from 0.1 to 10 weight percent structural units of one or more acid monomers, based on the weight of the polymer particles.
Other monomers such as acrylonitrile, acrylamide or Ci-Ce-alkyl acrylamides, and multiethylenically unsaturated monomers including divinyl benzene and allyl methacrylate may also be used in the preparation of the polymer particles. The z-average particle size of the polymer particles as measured using dynamic light scattering is in the range of from 50 nm or from 80 nm, to 500 nm or to 300 nm or to 200 nm.
The mole-to-mole ratio of the t-C4-Cw-alkyl hydroperoxide to the reductant in the chase step is in the range of from 1:1 or from 3:1 or from 3.5: 1 or from 4.5:1 or from 5.5: 1 or from 6.5: 1 or from 7.0: 1, to 50:1 or to 30:1 or to 20: 1 or to 15: 1 or to 10:1. The efficiency of this redox system can be controlled by a number of factors including the optional addition of a) a catalytic amount of a redox reaction catalyzing metal salt such as a salt of iron (II) such as FeSC , copper, manganese, vanadium, silver, platinum, nickel, chromium, palladium, or cobalt, or combinations thereof; b) addition of a chelating agent for the metal salt; c) adjustment of temperature; and d) adjustment of pH.
Accordingly, the r-Cr-Cio-alkyl hydroperoxide and reductant, optionally in the presence of a catalyzing metal salt and a chelating agent, may be contacted with the aqueous dispersion of polymer particles in a single stage or in multiple stages using the same or different mole-to-mole ratios in each stage, provided the mole-to-mole ratio of the total amount of /-Cr-Cio-alkyl hydroperoxide added to the total amount of reductant added over multiple steps is in the prescribed range.
The resultant aqueous dispersion of polymer particles is preferably neutralized to a pH in the range of from 7.5 or from 8.0 or from 8.5 or from 8.8, to 10.0 or to 9.5 or to 9.2.
The resultant composition comprises from 125 ppm or from 150 ppm or from 175 ppm or from 225 ppm or from 275 ppm or from 350 ppm, to 2500 ppm or to 1250 ppm or to 1500 ppm of FCr-Cio-alkyl hydroperoxide and preferably less than 1000 ppm, more preferably less than 500 ppm of residual monomer. The concentration of the z-C4-C -alkyl hydroperoxide in the composition is determined using NMR spectroscopy as detailed in the experimental section.
In another aspect, the present invention is a method comprising the steps of: a) contacting, under emulsion polymerization conditions, monomers comprising an acrylate monomer, a methacrylate monomer, and an acid monomer to form an aqueous dispersion of acrylic-based polymer particles and residual monomers; b) contacting the dispersion of the acrylic-based polymer particles with a reductant and a t-Cr-Cio-alkyl hydroperoxide to reduce the concentration of residual monomers in the aqueous dispersion to less than 1000 ppm of residual monomers; wherein the mole-to-mole ratio of the t-C4-Cio-alkyl hydroperoxide to reductant is in the range of from 1:1 to 50:1.
The composition of the present invention has been found to be resistant to the growth of mold, bacteria, and yeast under heat age conditions. Examples
NMR Spectroscopic Determination of /-AHP or /-BHP in Serum Phase
A 10-mL polycarbonate tube was charged with 3.0 mL of a latex sample, 3.0 mL of Milli-Q water, and centrifuged at 100,000 rpm for 15 min. The resulting clear supernatant was decanted and transferred into a 5 -mm NMR tube. A flame-sealed capillary tube filled with an external standard (5.00 wt% d4-sodium trimethylsilylpropionate in D2O) was added to the NMR tube. Careful attention was paid to proper alignment of the external standard within the NMR tube. NMR spectra were obtained using the Bruker A VANCE III 600 spectrometer equipped with a 5-mm BroadBand CryoProbe. Each sample was tuned and shimmed individually but pulse widths and receiver gain were held constant for a sample series. Concentration of free /-amyl hydroperoxide was measured by using the zg pulse sequence with the following parameters: acquisition time (aq) = 2.5 s, recycle delay (dl) = 30 s, number of transients (ns) = 1024, receiver gain (rg) = 32, and pulsewidth (pl) = 11 ms. All other parameters (time domain size, sweep width, dwell time, pre-scan delay, and carrier frequency) were left at the default values. Concentration of free hydroperoxide was calculated by comparing the integrations of peaks resonating around 1.2 ppm and the peak for the external standard at 0.0 ppm. Spectra were referenced to the external standard at 0.0 ppm on the trimethylsilyl chemical shift scale. The purity of the resonances ascribed to hydroperoxides were unambiguously confirmed with a 'H-13C heteronuclear multiple bond coherence (HMBC) experiment using the hmbcgplpndqf pulse sequence. SSS oligomer content was calculated by comparing the normalized integrations of peaks resonating around 7 ppm and the peak for the external standard at 0.0 ppm. Integral normalization was estimated by using a diffusion-ordered spectroscopy (DOSY) experiment using the ledbpgp2s pulse sequence to determine the weighted average mass of the SSS oligomers.
Preparation of Samples for Microbial Resistance
Samples were tested for microbial resistance “as-is” (not heat-aged) as well as after being subjected to 50 °C for four-weeks (heat-aged). A 10-g aliquot was taken from each sample and inoculated three times at 7-d intervals with 106-107 colony forming units per milliliter of sample (CFU/mL) of a standard pool of bacteria, yeasts, and molds obtained from American Type Culture Collection (ATCC) that are common contaminants in coatings. Once inoculated, the samples were stored in 25 °C incubators. Test samples were monitored for microbial contamination by agar plating using a standard streak plate method. Samples were plated 1 d and 7 d after each microbial challenge onto trypticase soy agar (TSA) and potato dextrose agar (PDA) plates. All agar plates were checked daily up to 7 d after plating to determine the number of microorganisms surviving in the test samples. Between checks, the agar plates were stored in incubators at 30 °C for TSA plates and at 25 °C for PDA plates. The extent of microbial contamination was established by counting the colonies, where the rating score was determined from the number of microbial colonies observed on the agar plates. Reported results come from day 7 readings, and are summarized for both the “as-is” and heat-aged samples. Results are described by the rating score for each type of microorganism: B = bacteria, Y = yeast, and M = mold. For example, a 3B describes a plate with 3 rating score for bacteria, or a Tr Y(l) describes a plate with trace yeast (1 colony on plate). Table 1 illustrates the rating system used to estimate the level of microbial contamination on streak plates. Colonies refers to the number of colonies on the plate.
Table 1 - Rating system for estimating microbial contamination
Figure imgf000007_0001
In Table 1, “Pass” means fewer than ten colonies were detected on plates on the specified day (Day 1 (DI) or Day 7 (D7)) after inoculation. “Fail means that ten or more distinct colonies were detected on plates on the specified day after inoculation. Comparative Example 1 - Method for Preparing an Acrylic Latex
A monomer emulsion was prepared by mixing deionized water (800 g), sodium lauryl sulfate (16.59 g, 28% active), zi-butyl acrylate (1016.58 g), methyl methacrylate (889.53 g), ureido methacrylate (39.1 g, 50% active), methacrylic acid (19.55 g), and sodium 4-vinylbenzene sulfonate (10.87 g, 90% active).
To a 5-L, four necked round bottom flask equipped with a paddle stirrer, a thermometer, N2 inlet, and a reflux condenser was added deionized water (730 g), sodium lauryl sulfate (19.73 g, 28% active), and an aqueous solution of sodium carbonate (6.84 g) dissolved in deionized water (70 g). The contents of the flask were heated to 87 °C under N2 and stirring was initiated.
A portion of the monomer emulsion (58.8 g) was then added to the flask, quickly followed by the addition of an aqueous solution of ammonium persulfate (6.8 g) dissolved in deionized water (20 g), followed by a rinse of deionized water (5 g). After stirring for 5 min, the remainder of the monomer emulsion and a solution containing ammonium persulfate (1.04 g) dissolved in deionized water (92 g) were each added separately to the flask over a total period of 65 min. The contents of the flask were maintained at 87 °C during the addition of monomer emulsion. When all additions were complete, the vessel containing residual monomer emulsion was rinsed with deionized water (25 g), which was then added to the flask. The contents of the flask were cooled to 75 °C and an aqueous solution of FeSCU (20.1 g, 0.1% solids) and an aqueous solution of the tetrasodium salt of EDTA (2 g, 1% solids) were added to the kettle. A catalyst / activator pair of a) r-amyl hydroperoxide (r-AHP, 1.27 g, 85% active) dispersed in 40 g of deionized water, and b) isoascorbic acid (IAA, 0.75 g) dissolved in 40 g of deionized water were then added linearly and separately to the flask over 20 min. The contents of the flask were maintained at 75 °C during the addition of the catalyst / activator pair.
The polymer was then neutralized to pH ~ 9.0 with an aqueous solution of ammonium hydroxide and deionized water. The z-average particle size was found to be 116 nm using a Brookhaven BI-90 Plus Particle Size Analyzer; the measured solids was 50.3%.
Examples 1-4 - Method for Preparing an Acrylic Latex with Excess t-AHP
The method of Comparative Example 1 was repeated except that the amount by weight of /- AHP added after the flask was cooled to 75 °C was increased 2-fold (Example 1), 3-fold (Example 2), 4-fold (Example 2), and 5-fold (Example 4). Table 2 illustrates the relative concentrations of t-AHP added with respect to Comparative Example 1 , as well as the concentrations of t-AHP and /-amyl hydroperoxide (t-AmOH) measured in the final neutralized dispersion.
Table 2 - Relative Concentrations of t-AHP
Figure imgf000009_0001
Table 3 illustrates the heat-age challenge test results for the samples.
Table 3 - Heat- Age Challenge Test Results
Figure imgf000009_0002
The data demonstrate that increased levels of t-AHP are effective in preserving acrylic-based latexes against microbial growth.

Claims

Claims:
1. A composition comprising a) an aqueous dispersion of acrylic-based polymer particles having a z-average particle size as measured using dynamic light scattering in the range of from 50 nm to 500 nm; and b) a C4-Cio-alkyl hydroperoxide having a concentration in the range of from
125 ppm to 2500 ppm, based on the weight of the composition.
2. The composition of Claim 1 wherein the concentration of the C4-Cio-alkyl hydroperoxide is in range of from 150 ppm to 1250 ppm, and the C4-Cw-alkyl hydroperoxide is /-butyl hydroperoxide or /-amyl hydroperoxide or a combination thereof; wherein the composition has a pH in the range of from 7.5 to 10.0.
3. The composition of Claim 1 wherein the concentration of the C4-Cio-alkyl hydroperoxide is in range of from 225 ppm to 1250 ppm, and the C4-Cw-alkyl hydroperoxide is /-amyl hydroperoxide; wherein the composition has a pH in the range of from 8.0 to 9.5.
4. The composition of Claim 3 wherein the concentration of the C4-Cio-alkyl hydroperoxide is in the range of from 275 ppm to 750 ppm.
5. The composition of Claim 4 wherein the C4-Cio-alkyl hydroperoxide is t-butyl hydroperoxide or /-amyl hydroperoxide or a combination thereof.
6. The composition of Claim 5 wherein the C4-Cio-alkyl hydroperoxide is t-amyl hydroperoxide.
7. The composition of any of Claims 1-6 wherein the acrylic-based polymer particles comprise structural units of a methacrylate, an acrylate, and an acid monomer, wherein the methacrylate is methyl methacrylate; the acrylate comprises butyl acrylate or 2-ethylhexyl acrylate or a combination thereof; and the acid comprises acrylic acid or methacrylic acid.
8. The composition of Claim 7 wherein the acid further comprises sodium 4-vinylbenzene sulfonate.
PCT/US2023/074314 2022-09-20 2023-09-15 Microbe resistant acrylic latex composition WO2024064581A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US202263408300P 2022-09-20 2022-09-20
US63/408,300 2022-09-20

Publications (1)

Publication Number Publication Date
WO2024064581A1 true WO2024064581A1 (en) 2024-03-28

Family

ID=88297057

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2023/074314 WO2024064581A1 (en) 2022-09-20 2023-09-15 Microbe resistant acrylic latex composition

Country Status (1)

Country Link
WO (1) WO2024064581A1 (en)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20020160118A1 (en) * 2001-02-23 2002-10-31 Even Ralph Craig Coating method
US20140221560A1 (en) * 2013-02-04 2014-08-07 Rohm And Haas Company Acrylic Latex Binder and Method of Preparation
US8993667B2 (en) * 2013-03-15 2015-03-31 Rohm And Haas Company Redox polymers for improved dirt and water resistance for elastomeric wall and roof coatings
EP3456787B1 (en) 2017-09-14 2021-06-23 Daw Se Water-borne coating formulation
US20220275238A1 (en) * 2019-08-09 2022-09-01 Rohm And Haas Company Blend of polyacrylic and polyvinyl acetate latexes

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20020160118A1 (en) * 2001-02-23 2002-10-31 Even Ralph Craig Coating method
US20140221560A1 (en) * 2013-02-04 2014-08-07 Rohm And Haas Company Acrylic Latex Binder and Method of Preparation
US8993667B2 (en) * 2013-03-15 2015-03-31 Rohm And Haas Company Redox polymers for improved dirt and water resistance for elastomeric wall and roof coatings
EP3456787B1 (en) 2017-09-14 2021-06-23 Daw Se Water-borne coating formulation
US20220275238A1 (en) * 2019-08-09 2022-09-01 Rohm And Haas Company Blend of polyacrylic and polyvinyl acetate latexes

Similar Documents

Publication Publication Date Title
WO2023192105A1 (en) Aqueous dispersion of biocide-free organic opacifying pigment particles
WO2023192106A1 (en) Method for preparing an aqueous dispersion of biocide-free organic opacifying pigment particles
EP1023335A1 (en) Method for reducing the content of residual monomers in aqueous polymer dispersions
KR100330060B1 (en) Process for shortstopping emulsion polymerizations which does not generate nitrosamines
CN108373526B (en) Antifouling and antibacterial polycarboxylate superplasticizer and preparation method thereof
WO2010083089A1 (en) Increased monomer conversion in emulsion polymerization
WO2024064581A1 (en) Microbe resistant acrylic latex composition
US3997707A (en) Method for suspension-polymerizing vinyl chloride
WO2024064582A1 (en) Method for preparing a microbe resistant acrylic latex
WO2024064583A1 (en) Method for preparing a microbe resistant styrenic latex
WO2024064584A1 (en) Microbe resistant styrenic latex composition
EP0884945A1 (en) Use of polymers as biocides
CN107022043A (en) A kind of preparation method and its usage of cuprous oxide composite
CA1085548A (en) Method for preparing biologically active polymers
De Stefano et al. Quantitative parameters for the sequestering capacity of polyacrylates towards alkaline earth metal ions
EP3677603A1 (en) Method for producing oxyethylene chain-containing vinyl ether polymer by radical polymerization
US20070129461A1 (en) Antifouling polymeric agent for marine applications
EP4045544A1 (en) Super advanced controlled radical polymerization
US4701507A (en) Process for the incorporation of functionalized monomers
US11414511B2 (en) Carboxymethyl inulin graft polymer scale and corrosion inhibitor and preparation method thereof
DE1917858A1 (en) Polymerization catalyst and process for the polymerization and copolymerization of olefins
WO2008090153A2 (en) Method for producing homopolymers and copolymers of vinylphosphonic acid
EP4306554A1 (en) Method for producing polymer, composition for radical polymerization, and radical polymerization inhibitor
JP2005048024A (en) Scale deposition preventive agent for polymerization reactor
WO2018091348A1 (en) A synergistically active composition

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 23786446

Country of ref document: EP

Kind code of ref document: A1