Preparation of an aqueous dispersion of acrylate-siloxane copolymer particles

Abstract

The present invention relates to a method for preparing an aqueous dispersion of acrylate-siloxane copolymer particles as described herein. The polymer particles comprise an acrylate monomer; an acid monomer; and a structural unit of a siloxane acrylate monomer of Formula I: I In the above formula, R, R1, R2, Y, and x are as defined herein. The method provides an efficient method for preparing a high solid content aqueous dispersion of a siloxane-acrylate hybrid copolymer by efficiently incorporating siloxane acrylate monomers, low residual monomers, and low formation of unwanted coagulations. The dispersion is useful for forming coatings having improved hydrophobicity, stain resistance, and aesthetic / tactile properties compared to conventional total-acrylate compositions.

Description

Background Technology

[0001] The present invention relates to an aqueous dispersion of copolymer particles comprising structural units of an acrylate monomer and a siloxane-acrylate monomer.

[0002] Siloxane-acrylate hybrid latex compositions comprising polymer particles prepared by the polymerization of acrylates and siloxane-functionalized monomers are desirable because they form coatings with improved hydrophobicity, stain resistance, and aesthetic / tactile properties compared to conventional all-acrylate compositions. Unfortunately, the methods used to prepare these hybrid systems (e.g., in the literature [Xiao, J. et al. , Prog. Org. Coat. 2018 , 116 , 1-6]; and literature[Zhang, B. et al. , Appl. Surf. Sci. 2007 , 254 The inventors have found that (as described in [ , 452-458]) results in the formation of latex containing unacceptably high levels of unreacted residual monomer and / or unwanted gelled oligomer byproducts at commercially useful solid concentrations. The formation of high-concentration gel, which is a strong indicator of an inefficient process, causes reactor contamination and can contribute to the inferior properties of the final coating.

[0003] On the other hand, the mixture of total-acrylic polymer particles and siloxane-based polymer particles undergoes phase separation upon drying, which manifests as macrophase separation and substrate de-wetting, as well as the formation of optically opaque films.

[0004] Therefore, it would be advantageous to prepare an aqueous dispersion of high-solid-level siloxane-acrylate hybrid copolymer particles having an acceptable low level of gel formation, unreacted monomers, and high silicon incorporation.

[0005] The present invention addresses the needs of the art by providing, in one embodiment, an aqueous dispersion of polymer particles having a z-average particle size in the range of 50 nm to 500 nm, and, based on the weight of the polymer particles, a) structural units of 40 to 98.8 weight% of an acrylate monomer; b) structural units of 0.1 to 5 weight% of an acid monomer; and c) structural units of 1 to 59.8 weight% of a siloxane acrylate monomer having the following chemical formula I:

[0006]

[0007] I

[0008] In the above formula, R is H or CH3;

[0009] R 1 is H or CH3;

[0010] Each R 2 is independently CH3 or O-Si(CH3)3;

[0011] Y is ―CH2― or ―CH2CH2― and;

[0012] x is 0 or 1, and;

[0013] However, when x is 1, R 1 is H; when Y is -CH2-, R 1 is H; when Y is -CH2CH2-, R 1 is CH3 and x is 0;

[0014] Here, the solid content of polymer particles in the aqueous dispersion is in the range of 30 to 55 weight%, and a) the aqueous phase of the aqueous dispersion contains monomers of Formula I at a concentration of 1000 ppm or less; or b) the aqueous phase of the aqueous dispersion contains coagulated material at a concentration of 10000 ppm or less.

[0015] In a second aspect, the present invention is a method for preparing an aqueous dispersion of acrylate-siloxane copolymer particles comprising the following steps:

[0016] 1) a step of contacting an aqueous monomer emulsion with an initiator at a temperature maintained in the range of 60°C to 95°C in the presence of water and a surfactant in a stirred vessel, and then,

[0017] 2) A step of giving sufficient time to substantially and completely convert the monomer into polymer particles containing the structural units of the monomer;

[0018] Herein, the monomer emulsion comprises, based on the weight of the monomers, a) 40 to 98.8 weight% of an acrylate monomer; b) 0.1 to 5 weight% of an acid monomer; and c) 1 to 59.8 weight% of a siloxane acrylate monomer of Formula I:

[0019]

[0020] I

[0021] In the above equation, R, R 1 , R 2 , Y and x are as previously defined.

[0022] The composition of the present invention addresses the need by providing a dispersion of siloxane-acrylate hybrid copolymer particles having a) a relatively high degree of silicon incorporation; b) a high solid content; and c) a low residual monomer. Specific details for implementing the invention

[0023] In a first embodiment, the present invention is a composition comprising an aqueous dispersion of polymer particles having a z-average particle size in the range of 50 nm to 500 nm, and, based on the weight of the polymer particles, a) 40 to 98.8 weight% of structural units of an acrylate monomer; b) 0.1 to 5 weight% of structural units of an acid monomer; and c) 1 to 59.8 weight% of structural units of a siloxane acrylate monomer having the following formula I:

[0024]

[0025] I

[0026] In the above formula, R is H or CH3;

[0027] R 1 is H or CH3;

[0028] Each R 2 is independently CH3 or O-Si(CH3)3;

[0029] Y is ―CH2― or ―CH2CH2― and;

[0030] x is 0 or 1, and;

[0031] However, when x is 1, R 1 is H; when Y is -CH2-, R 1 is H; when Y is -CH2CH2-, R 1 is CH3 and x is 0;

[0032] Here, the solid content of polymer particles in the aqueous dispersion is in the range of 30 to 55 weight%, and a) the aqueous phase of the aqueous dispersion contains monomers of Formula I at a concentration of 1000 ppm or less; or b) the aqueous phase of the aqueous dispersion contains coagulated material at a concentration of 10000 ppm or less.

[0033] As used herein, the term “structural unit” of the cited monomer refers to the remainder of the monomer after polymerization. For example, the structural units of methyl methacrylate (MMA) are exemplified as follows:

[0034]

[0035] In the above formula, the dotted line indicates the attachment point of the structural unit to the polymer backbone.

[0036] As used herein, the term "acrylate monomer" refers to one or more acrylate and / or methacrylate monomers. MMA, n - Butyl methacrylate (BMA), ethyl acrylate (EA), nExamples of suitable acrylate monomers including butyl acrylate (BA) and 2-ethylhexyl acrylate (2-EHA). Preferably, 80 weight percent or more of the acrylate monomer, more preferably 90 weight percent or more, is a combination of MMA and BA.

[0037] The copolymer also preferably comprises 0.1 to 5 weight percent of structural units of acid monomers, such as carboxylic acid monomers, phosphate monomers, or sulfate monomers, based on the weight of the copolymer. Examples of carboxylic acid monomers include acrylic acid (AA), methacrylic acid (MAA), and itaconic acid (IA) and their salts.

[0038] Suitable phosphonic acid monomers comprising phosphonates and dihydrogen phosphate esters of alcohols containing or substituted with polymerizable vinyl or olefin groups. Preferred dihydrogen phosphate esters are phosphates of hydroxyalkyl acrylates or methacrylates, including phosphoethyl methacrylate (PEM) and phosphopropyl methacrylate.

[0039] Examples of suitable sulfuric acid monomers include sulfoethyl methacrylate, sulfopropyl methacrylate, styrene sulfonic acid, vinyl sulfonic acid, and 2-acrylamido-2-methylpropanesulfonic acid (AMPS), and salts thereof.

[0040] Preferably, the copolymer comprises structural units of MMA, BA, MAA, and siloxane acrylate monomer of formula I.

[0041] In one embodiment, the weight-to-weight ratio of structural units of BA to structural units of MMA ranges from 45:55 to 55:45; in another embodiment, the weight-to-weight ratio of structural units of the total acrylate monomer, preferably BA and MMA, to the acid monomer, preferably MAA, ranges from 99.95:0.05 to 98:2. In another embodiment, based on the weight of the polymer particles, the weight percentage of structural units of the siloxane acrylate monomer ranges from 5 to 30%.

[0042] In another embodiment, the polymer particles comprise structural units of a siloxane monomer in an amount of preferably 2, more preferably 3, and most preferably 8 weight% based on the weight of the polymer particles, preferably up to 50, more preferably up to 40, even more preferably up to 30, and most preferably up to 20 weight% of a siloxane acrylate monomer.

[0043] Preferably, the polymer particles contain silicon in an amount of 3 to, more preferably 5 weight percent, up to 30, preferably up to 20 weight percent, based on the weight of the polymer particles.

[0044] Preferably, the weight-to-weight ratio of siloxane acrylate monomer to structural unit of siloxane acrylate monomer in the composition is as described herein. 1 As measured by H NMR spectroscopy, it is at least 98:2; more preferably 99:1; and most preferably at least 99.9:0.1.

[0045] Examples of monomers of chemical formula I include the following:

[0046]

[0047] M3T'-ALMA

[0048]

[0049] MD'M-1EO-ALMA

[0050]

[0051] MM'-ALMA

[0052]

[0053] MM'-1EO-ALMA

[0054]

[0055] MD'M-IPMA

[0056]

[0057] MD'M-ALMA

[0058] In another aspect, the present invention is preferably a method for preparing an aqueous dispersion of an acrylate-siloxane copolymer comprising the following steps:

[0059] 1) a first portion of an aqueous monomer emulsion having an average monomer droplet size in the range of 1 μm to 30 μm is added to a stirred vessel containing water and a surfactant, and heated to a temperature in the range of 60°C to, preferably 80°C to 95°C; then

[0060] 2) a step of adding the first portion of the initiator to a container to form an aqueous dispersion of seed polymer particles over time; then

[0061] 3) A step of slowly adding the second part of the monomer emulsion and the second part of the initiator to the container; then

[0062] 4) A step of maintaining a temperature of 60°C, preferably in the range of 80°C to 95°C, for a time sufficient to achieve substantially complete conversion of the monomer into polymer particles containing structural units of the monomer;

[0063] Herein, the monomer emulsion comprises, based on the weight of the monomers, a) 40 to 98.8 weight% of an acrylate monomer; b) 0.1 to 5 weight% of an acid monomer; and c) 1 to 59.8 weight% of a siloxane acrylate monomer of Formula I:

[0064]

[0065] I

[0066] In the above formula, R is H or CH3;

[0067] R 1 is H or CH3;

[0068] Each R 2 is independently CH3 or O-Si(CH3)3;

[0069] Y is ―CH2― or ―CH2CH2― and;

[0070] x is 0 or 1, and;

[0071] However, when x is 1, R 1 is H; when Y is -CH2-, R 1 is H; when Y is -CH2CH2-, R 1 is CH3, and x is 0.

[0072] Preferably, after step 4), the redox initiator package is added to the container; and after step 4), the aqueous dispersion is also preferably neutralized to a pH range of 6.5 to 7.5. More preferably, after step 4), the redox initiator package is added and then neutralized.

[0073] In a more particularly preferred method, the composition of the present invention is prepared by emulsion polymerization, wherein the monomer emulsion comprises an acrylate monomer, preferably a combination of BA and MMA, and an acid monomer, preferably MAA; and the siloxane acrylate monomer dispersed in water is homogenized in the presence of a surfactant and preferably a chain transfer agent to produce a monomer emulsion having an average particle size in the range of 1 to 30 μm when measured by an optical microscope.

[0074] Then, the monomer emulsion and an initiator such as ammonium persulfate are fed into a heated reactor (typically in the range of 85°C to 90°C) containing water and a surfactant for 30 minutes to 6 hours. The reactor is maintained for a time sufficient to substantially complete the polymerization, generally 15 minutes to 2 hours, after which the reactor is cooled to about 60°C. Then, the contents are preferably t - It is treated with a redox pairing agent (also known as a redox initiator package) such as amyl hydroperoxide / isoascorbic acid and then neutralized. Polymer particles produced by this method preferably have a z-average particle size in the range of 80 nm to 200 nm, more preferably 150 nm.

[0075] An aqueous dispersion of polymer particles comprising structural units of an acrylate monomer and a siloxane-acrylate monomer of Formula I is described herein 1When measured using H NMR spectroscopy, it was confirmed that a solid content ranging from 30, preferably 35, most preferably 38, to 55, preferably 50, and most preferably 45 wt% can be obtained with a quantitative incorporation of 70 mol percent or more, preferably 80 mol percent or more, more preferably 90 mol percent or more, of siloxane acrylate monomer into latex polymer particles. Consequently, the dispersion preferably contains 1000 ppm or less, more preferably 500 ppm or less, even more preferably 100 ppm or less, and most preferably 30 ppm or less of residual unreacted monomer. Additionally, the amount of the resulting coagulated material (gel) is preferably 10000 ppm or less, more preferably 7600 ppm or less, and most preferably 5000 ppm or less. Preferably, the amount of residual monomer is 1000 ppm or less, and the amount of the resulting gel is 10000 ppm or less. The concentration of coagulated material is determined by filtering the composition through a continuous stainless steel mesh screen with pore sizes of 150 μm and 40 μm to separate the residue; thus, according to inference, the particle size of the coagulated material is > 40 μm.

[0076] Particle size measurement method

[0077] Particle size was Z-average particle size using dynamic light scattering (DLS) at a scattering angle of 90° using Zetasizer software version 7.11 ( D z Particle size was measured using a Malvern Zetasizer Nano ZS90. A drop of the sample dispersion was diluted with an aqueous solution of MilliQ water (18.2 MΩ·cm at 25°C) to achieve particle numbers ranging from 200 to 400,000 counts / s (Kcps). Particle size measurements were performed using the instrument's particle size measurement method. D z It was calculated by software. D z is also known as the average particle size of the intensity-based harmonic mean and is expressed as follows:

[0078]

[0079] Here, S i is the diameter D i particles having i It is the scattering intensity from. Details D z The calculation is described in ISO 22412:2017 (Particle Size Analysis - Dynamic Light Scattering (DLS)).

[0080] Integration and Hydrolysis of Silicon-Containing Monomer NMR Spectroscopy

[0081] The procedure for determining the percentage of silicon monomer incorporation is as follows. The sample was diluted with a known mass of deionized water to ~10X its concentration in water, placed in an LDPE centrifuge tube, and spun at 100 kJ for 20 minutes. The supernatant was removed from the tube, and the solid polymer at the bottom of the tube was thoroughly rinsed with deionized water. The spin-down polymer sample remaining in the centrifuge tube was dried at room temperature for 48 hours. A known mass of the polymer sample was dissolved in ~2 to 5 mL of CHCl3, and using a Bruker 300 MHz NMR 1 ¹H NMR spectroscopy was performed. The acquired spectrum consisted of an average of 32 scans with a relaxation delay of 10 seconds. The combined value of the siloxane peak (~0.0 to 0.1 ppm) and butyl acrylate (3.7 to 4.1 ppm, -(C=O)-C H 2 -) and methyl methacrylate side chain peak (3.4 to 3.6 ppm, -C H 3The ratio of the integrated values ​​of ) was used to calculate the composition of the sample (all chemical shifts for residual protons of CDCl3 at 7.26 ppm), and these values ​​were compared with the monomer emulsion (ME) composition to estimate the total incorporation % of silicon-containing monomers.

[0082] Measurement of siloxane acrylate monomers in serum by UHPLC-MS

[0083] UPHLC-MS was performed on a Waters Acquity® Ultra High Performance Liquid Chromatography (UPLC) system equipped with a Waters Acquity® UPLC BEH-C18 (1 x 50 mm) column coupled to a Waters Acquity Photodiode Array (PDA) detector operating in the wavelength range of 190 to 500 nm. Standards were prepared by serially diluting stock solutions of monomers (~1 wt%) at known concentrations in acetonitrile. Duplicate samples were prepared by diluting a sample of a known mass in acetonitrile to ~30X and stirring for ~2 hours. The samples were then centrifuged at 43,000 RPM for 15 minutes. The supernatant was removed with a pipette and filtered using a 0.2 μm PTFE syringe filter for injection into the instrument. The sample injection volume was 2.0 μL, and the injection mode was partial-loop with a 5 μL needle overfill. The instrument was operated at a flow rate of 0.1 mL / min and a column temperature of 40°C using mobile phase (A): 0.1 wt% formic acid in H2O and mobile phase (B): 0.1 wt% formic acid in acetonitrile. The solvent gradient was programmed as follows: 85 / 15(v / v) (A) / (B) for 2.75 min, a maximum of 99 / 1(A) / (B) for 0.25 min, maintained at 99 / 1(A) / (B) for 1.0 min, reduced to 85 / 15(A) / (B) over 0.25 min, and then maintained at 85 / 15(A) / (B) for 1.75 min. The LOD of the method was 30 ppm.

[0084] Examples

[0085] Intermediate Example 1 - Preparation of MD'M-IPMA

[0086] A. Preparation of Isoprenyl MD'M Alcohol

[0087] Isoprenol (165.8 g) was filled into a 4-neck 1 L round-bottom flask equipped with a mechanical stirrer, thermocouple, and a water-cooled condenser suitable for an N2 bubbler. The unfilled space of the flask was purged with N2 for 3 minutes. The flask was heated, and 15 ppm of Pt was added to the flask. 1,1,1,3,5,5,5-heptamethyltrisiloxane (MD'M, 385.0 g) was added to the flask over a period of 1.5 hours, and the pot temperature was adjusted to the range of 80 to 90°C. The mixture was stirred at 80 to 90°C for an additional 1.5 hours. FTIR spectroscopy showed a Si-H vibration peak (~2140 cm⁻¹). -1 It was found that ) had completely disappeared. Volatile substances were removed for 1 hour at 50°C vacuum and < 1 mm Hg. The crude product (512 g) was a brown liquid. Activated carbon (23 g) was added, and the mixture was stirred for 2 hours and then filtered through a 0.45 μm filter membrane. A clear, colorless final product (495.4 g) was collected (yield 92.8%). 1 H, 13 C and 29 The characteristics of the product were confirmed using Si NMR spectroscopy and GC-FID.

[0088] B. MD'M-IPMA Manufacturing

[0089] Isoprenyl MD'M alcohol (155.3 g), MMA (152.4 g), and Zr(acac)4 (3.34 g) were loaded into a 1-L 4-neck round-bottom flask equipped with a 10-plate Oldershaw distillation column / distillation head, an overhead stirrer, a temperature controller with over-temperature protection, an overhead temperature monitor, a gas inlet tube, and an automatic reflux splitter / controller. Subsequently, hydroquinone monomethyl ether (280 mg) and 4-hydroxy-TEMPO (20 mg) were added to the reaction mixture to achieve 1338 ppm and 288 ppm in the final product, respectively. Gas purging (8% O2 in N2) was initiated, and stirring was started. Samples of the port contents were taken for NMR spectroscopic analysis. The flask pressure was reduced to 550 mm Hg, the contents of the pot were slowly heated to between 96 and 106°C, and refluxed for about 1 hour. The vapor temperature stabilized between 58 and 56°C. The MMA-methanol azeotropic mixture was distilled off at a vapor temperature of 56°C using a reflux ratio of 70:30. Distillation was continued until the vapor temperature reached 65°C. After cooling the contents of the flask to 70°C, 1 A fraction was removed for H NMR spectroscopic analysis. Excess MMA was removed from the final monomer by distillation at a pot temperature of 65°C and 150 mm Hg. The final product was an amber, low-viscosity liquid (185 g).

[0090] Example 1 - Preparation of an aqueous dispersion of hybrid polymer particles using MM'-ALMA

[0091] Deionized water (50.0 g) and Polystep B-5-N sodium lauryl sulfate (SLS, 0.5 g, 28.0% in water) were added to a 500-mL, four-necked round-bottom flask equipped with a condenser, overhead stirrer, and thermocouple. The contents of the reactor were stirred at 250 rpm and heated to 88°C under N2. In a separate container, deionized water (60.0 g), SLS (4.7 g, 28.0% in water), BA (45.0 g), MMA (45.0 g), MAA (1.0 g), MM'-ALMA (10.0 g), n - Dodecyl mercaptan ( n A monomer emulsion (ME) containing 0.05 g of DDM, 0.05 g of ammonium hydroxide solution (0.36 g, 28% active in water), and 0.3 g of sodium acetate was prepared using an overhead mixer and then processed for 1 minute using a portable homogenizer (Tissue Tearor, Model 985370, Biospec Products Inc.) to produce ME with an average droplet size of ~2 to 15 μm as measured by an optical microscope. A portion of the ME (1.75 g) was added to the reactor while rinsing (5.0 g water), and then ammonium persulfate (0.03 g) was added while rinsing (2.0 g water). The remaining ME and ammonium persulfate solution (0.11 g in 8.0 g water) were simultaneously fed into the reactor over 120 minutes at a temperature of 87 to 88°C. Once the supply was complete, the reactor was maintained at 87 to 88°C for an additional 30 minutes. Then, the reactor was cooled to 60°C, and ( i ) Luperox TAH 85 tert-amyl hydroperoxide (t-AHP, aqueous activity 85 wt%), SLS (0.02 g, aqueous activity 28%) and deionized water (1.0 g) and ( iiSeparate solutions of isoascorbic acid (IAA, 0.05 g), VERSENE™ (EDTA, trademark of Dow, Inc. or its affiliates, 0.1 g, aqueous activity 1%), and iron(II) sulfate solution (10.0 g, aqueous activity 0.15%) were added to the reactor. Subsequently, after cooling the reactor to room temperature, ammonium hydroxide solution (aqueous activity 28%) was added dropwise to adjust the pH to ~7.0. The aqueous dispersion was filtered sequentially through stainless steel mesh screens with pore sizes of 150 μm and 40 μm. The final aqueous particle dispersion consisted of 40% solids, a z-average particle size of 112 nm, 2900 ppm coagulants, and determined 1 Quantitative incorporation of MM'-ALMA monomer was determined by ¹H NMR spectroscopy. The level of residual MM'-ALMA in the sample was < 30 ppm as determined by UHPLC.

[0092] Example 2 - Preparation of an aqueous dispersion of hybrid polymer particles using MM'-1EO-ALMA

[0093] Deionized water (60.0 g), SLS (4.7 g, water activity 29%), BA (45.0 g), MMA (45.0 g), MAA (1.0 g), MM'-1EO-ALMA (10.0 g), n Example 1 was repeated except that a monomer emulsion was prepared by combining -DDM (0.05 g), ammonium hydroxide solution (0.36 g, aqueous active 28%), and sodium acetate (0.30 g). The final aqueous particle dispersion consisted of 40% solids, a z-average particle size of 100 nm, 6300 ppm coagulations, and 1 The quantitative incorporation of MM'-1EO-ALMA monomer was determined by ¹H NMR spectroscopy. The level of residual MM'-1EO-ALMA in the sample was found to be < 100 ppm by UHPLC.

[0094] Example 3 - Preparation of an aqueous dispersion of hybrid polymer particles using MD'M-ALMA

[0095] Repeat Example 1, but with deionized water (60.0 g), SLS (4.7 g, water activity 29%), BA (45.0 g), MMA (45.0 g), MAA (1.0 g), MD'M-ALMA (10.0 g), n A monomer emulsion was prepared by combining DDM (0.05 g), ammonium hydroxide solution (0.36 g, aqueous activity 28%), and sodium acetate (0.30 g). The final aqueous particle dispersion consisted of 40% solids, a z-average particle size of 104 nm, 7600 ppm of coagulation, and 1 The quantitative incorporation of MD'M-ALMA monomer was measured by H NMR spectroscopy. The level of residual MD'M-ALMA in the sample was found to be < 30 ppm by UHPLC.

[0096] Example 4 - Preparation of an aqueous dispersion of hybrid polymer particles using MD'M-IPMA

[0097] Repeat Example 1, but with deionized water (60.0 g), SLS (4.7 g, water activity 29%), BA (45.0 g), MMA (45.0 g), MAA (1.0 g), MD'M-IPMA (10.0 g), n A monomer emulsion was prepared by combining -DDM (0.05 g), ammonium hydroxide solution (0.36 g, aqueous activity 28%), and sodium acetate (0.30 g). The final aqueous particle dispersion consisted of 40% solids, a z-average particle size of 107 nm, 2500 ppm of coagulation, and 1 The quantitative incorporation of MD'M-IPMA monomer was measured by H NMR spectroscopy. The level of residual MD'M-IPMA in the sample was found to be < 100 ppm by UHPLC.

[0098] Example 5 - Preparation of an aqueous dispersion of hybrid polymer particles using M3T'-ALMA

[0099] Repeat Example 1, but with deionized water (60.0 g), SLS (4.7 g, water activity 29%), BA (45.0 g), MMA (45.0 g), MAA (1.0 g), M3T'-ALMA (10.0 g), n A monomer emulsion was prepared by combining -DDM (0.05 g), ammonium hydroxide solution (0.36 g, aqueous active 28%), and sodium acetate (0.30 g). The final aqueous particle dispersion consisted of 41% solids, a z-average particle size of 106 nm, 5000 ppm coagulants, and 1 The sample had 73% incorporation of M3T'-ALMA monomer as measured by H NMR spectroscopy. The level of residual M3T'-ALMA in the sample was < 300 ppm as determined by UHPLC.

[0100] Comparative Example 1 - Preparation of an aqueous dispersion of hybrid polymer particles using butyl-MD5M'-ALMA

[0101]

[0102] Butyl-MD5M'-ALMA

[0103] Repeat Example 1, but with deionized water (60.0 g), SLS (4.7 g, water activity 29%), BA (45.0 g), MMA (45.0 g), MAA (1.0 g), butyl-MD5M'-ALMA (10.0 g), n A monomer emulsion was prepared by combining -DDM (0.05 g), ammonium hydroxide solution (0.36 g, aqueous activity 28%), and sodium acetate (0.30 g). The final aqueous particle dispersion consisted of 39% solids, coagulated particles with a z-average particle size of 87 nm and 11,000 ppm, and 1 It had 11% incorporation of butyl-butyl-MD5M'-ALMA monomer as measured by 1H NMR spectroscopy. The level of residual butyl-MD5M'-ALMA in the sample measured by UHPLC was 1620 ppm.

[0104] Comparative Example 2 - Preparation of an aqueous dispersion of hybrid polymer particles using MD'M-ALMA by the Xiao process

[0105] Literature [Xiao, J. et al. , Prog. Org. Coatings 2018 , 116 The process for preparing the aqueous dispersion of hybrid particles as described in [1-6] was reproduced. The synthesis was performed using a 500-mL, four-necked round-bottom flask equipped with a condenser, an overhead stirrer, and a thermocouple. Deionized water (19.0 g) and SLS (1.43 g, 28.0% in water), TRITON™ X-100 polyethylene glycol tOctylphenyl ether (trademark of Dow, Inc. or its affiliates, 0.80 g) and sodium bicarbonate (NaHCO3; 0.40 g) were added to a flask. The contents of the reactor were stirred at 100 rpm and heated to 60°C under N2. In a separate container, deionized water containing ME (48.5 g), SLS (2.14 g, 28.0% in water), X-100 (1.20 g), BA (BA; 44.8 g), MMA (42.3 g), styrene (10.1 g), and AA (1.9 g) were prepared using an overhead mixer. A portion of ME (15.1 g) was added to the reactor, followed by the addition of ammonium persulfate (0.13 g) in deionized water (10.0 g), and the reactor temperature was increased to 80°C over 10 minutes. The remaining ME and ammonium persulfate solution (0.27 g in 20.0 g of water) were simultaneously fed into the reactor at a temperature of 80 to 81°C for 4.5 hours and 5 hours, respectively (i.e., ammonium persulfate supply continued for 30 minutes after the ME supply was completed). At the 3-hour mark of the supply, MD'M-ALMA (10.0 g) was added to the reactor. Once the ammonium persulfate supply was completed, the reactor was maintained at 80°C for an additional 30 minutes. Then, the reactor was cooled to room temperature, and ammonium hydroxide solution (28% water activity) was added dropwise to raise the pH to ~8.5. The aqueous dispersion was continuously filtered through a stainless steel mesh screen with a pore size of 150 μm. The final aqueous particle dispersion consisted of 44% solids (theoretical = 53%), a z-average particle size of 135 nm, and 8000 ppm of coagulation, 1 It had 37% incorporation of MD'M-ALMA monomer as determined by ¹H NMR spectroscopy. The level of residual MD'M-ALMA in the serum was 13,700 ppm as determined by UHPLC.

[0106] Comparative Example 3 - Preparation of an aqueous dispersion of hybrid polymer particles using MD'M-ALMA by the Zhang process

[0107] Literature [Zhang, B. et al. , Appl. Surf. Sci. 2007 , 254 The process for preparing an aqueous dispersion of hybrid particles as described in [ , 452-458] was reproduced. Deionized water (60.0 g), sodium dodecylbenzenesulfonic acid (0.30 g), and sorbitani monolaurate (0.50 g) were added to a 100 mL glass reactor equipped with a condenser, an overhead stirrer, and a thermocouple. The contents of the reactor were stirred at 100 rpm, heated to 80°C, and N2 was sprayed for 30 minutes. A monomer mixture consisting of MMA (12.0 g), BA (12.0 g), and MD'M-ALMA (1.2 g) was prepared in a separate container. The monomer mixture and an ammonium persulfate solution (0.05 g in 10.0 g of water) were simultaneously fed into the reactor over 120 minutes at a temperature of 80 to 81°C. Once feeding was complete, the reactor was maintained at 80 to 81°C for an additional 6 hours. Then, after cooling the reactor to room temperature, ammonium hydroxide solution (water active 28%) was added dropwise to raise the pH to ~7.0. The aqueous dispersion was continuously filtered through stainless steel mesh screens with pore sizes of 40 μm and 150 μm. The final aqueous particle dispersion contained 23% solids (theoretical = 26%), a z-average particle size of 64 nm, 20,000 ppm of coagulants, and 1 It had 20% incorporation of MD'M-ALMA monomer determined by H NMR spectroscopy. The level of residual MD'M-ALMA in the serum was 400 ppm (3.2% unreacted monomer, based on structural units and monomer weight of MD'M-ALMA in polymer particles) as measured by UHPLC.

[0108] Table 1 shows the solid content, residual monomer, and generated coagulant for each sample.

[0109]

[0110] All embodiments of the present invention were prepared with high solid content and undetectable residual monomer and / or high solid content and low coagulation. Table 2 illustrates the percentage of Si atoms incorporated into the polymer particles:

[0111]

[0112] The table describes two important features of the present invention: first, the method for preparing the dispersion of polymer particles is important; second, even if an efficient method is used, the siloxane acrylate monomer must contain 2 to 4 siloxane groups so that the monomer can be optimally incorporated into the polymer particles.

Claims

Claim 1 A method for preparing an aqueous dispersion of acrylate-siloxane copolymer particles comprising the following steps: 1) adding a first portion of an aqueous monomer emulsion into a stirred vessel containing water and a surfactant and heating the contents of the vessel to a temperature in the range of 80°C to 95°C; then 2) adding a first portion of an initiator to the vessel to form an aqueous dispersion of seed polymer particles over time; then 3) slowly adding a second portion of the aqueous monomer emulsion and a second portion of the initiator to the vessel; 4) maintaining the temperature in the range of 80°C to 95°C for a time in the range of 15 minutes to 2 hours; then 5) adding a redox initiator package to the vessel; wherein the monomer emulsion comprises, based on the weight of the monomer, a) 40 to 98.8 weight% of an acrylate monomer; b) 0.1 to 5 weight% of an acid monomer; and c) comprising 1 to 59.8 weight% of a siloxane acrylate monomer of Formula I: In the above formula, R is H or CH3 and R 1 is H or CH3; each R 2 is independently CH3 or O-Si(CH3)3; Y is ―CH2― or ―CH2CH2―; x is 0 or 1; provided that when x is 1, R 1 is H; when Y is -CH2-, R 1 is H; when Y is -CH2CH2-, R 1 is CH3, and x is 0. Claim 2 In claim 1, the siloxane acrylate monomer of formula I is as follows, method: ; ; In the above formula, R is H or CH3; ; ; ; or . Claim 3 A method according to claim 1, further comprising, after step 5), a step of neutralizing the aqueous dispersion to a pH in the range of 6.5 to 7.

5. Claim 4 A method according to claim 3, wherein 80 weight% or more of the acrylate monomer comprises methyl methacrylate and butyl acrylate, wherein the weight-to-weight ratio of methyl methacrylate to butyl acrylate is in the range of 45:55 to 55:

45. Claim 5 In claim 4, the monomer emulsion comprises 8 to 20 weight% of a siloxane acrylate monomer and 0.2 to 2 weight% of an acid monomer based on the weight of the monomer, wherein the acid monomer is methacrylic acid. Claim 6 delete Claim 7 delete Claim 8 delete

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