Reactive surfactants for freeze-thaw stable emulsion polymers and coatings thereof

Abstract

The invention provides aqueous coating composition having freeze thaw stability, comprising: (a) at least one latex polymer derived from at least one monomer and at least one reactive surfactant of the formula
R.sub.1O(CH.sub.2CHR.sub.2O).sub.x(CH.sub.2CH.sub.2O).sub.y(CH.sub.2CHR.sub.3O).sub.zR.sub.4
where R.sub.1 is either alkyl, aryl, alkylaryl, or aralkylaryl of 8-30 carbon atoms, R.sub.2 is CH.sub.2OCH.sub.2CHCH.sub.2 (AGE); R.sub.3 is either H, CH.sub.3, or CH.sub.2CH.sub.3; R.sub.4 is H or SO3M or PO3M where M is H or K, Na, NH.sub.4, NR.sub.4, alkanolamine, or other cationic species and x=2-100; y=4-200 and z=0-50.

Claims

1. A aqueous coating composition having freeze thaw stability, comprising: at least one latex polymer derived from at least one monomer and a combination of a reactive surfactant of the formula: ##STR00013## where R=CH.sub.3 or CH.sub.2CH.sub.3, n=1, 2, or 3; x is 2-10, y is 0-200, and z is 4-200; and a surfactant of the formula: ##STR00014## where n=2, x=20 and M.sup.+ is NH.sub.4.sup.+.

2. The coating composition of claim 1 having five cycles of freeze-thaw stability.

3. The aqueous coating composition having freeze thaw stability of claim 1 wherein said z of Formula I is 5 to 60.

4. The aqueous coating composition having freeze thaw stability of claim 3 wherein said z of Formula I is 5 to 40.

5. The aqueous coating composition having freeze thaw stability of claim 1 further comprising at least one additional surfactant selected from the group consisting of nonionic, anionic, cationic and zwitterionic surfactants.

6. The aqueous coating composition having freeze thaw stability of claim 1 wherein said n=2.

7. A method for imparting freeze/thaw stability to a latex which method comprises conducting a latex forming polymerization with a surfactant mixture comprising: (a) a reactive surfactant of the formula ##STR00015## where R=CH.sub.3 or CH.sub.2CH.sub.3, n=1, 2, or 3; x is 2-10, y is 0-200, and z is 4-200; and (b) a surfactant of the formula ##STR00016## where n=2, x=20 and M.sup.+ is NH.sub.4.sup.+.

8. The method of claim 7 wherein said latex has five cycles of freeze-thaw stability.

9. A method for imparting freeze/thaw stability to a latex which method comprises conducting a latex forming polymerization with a surfactant mixture comprising: (a) a surfactant of the formula ##STR00017## where R=CH.sub.3 or CH.sub.2CH.sub.3, n=1, 2, or 3; x is 2-10, y is 0-200, and z is 4-200; Z can be either SO.sub.3.sup. or PO.sub.3.sup.2, and M.sup.+ is Na.sup.+, K.sup.+, NH.sub.4.sup.+, or an alkanolamine and (b) a surfactant of the formula ##STR00018## where n=3 and x=10.

Description

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(1) The present invention is directed to novel reactive surfactants, the use of the surfactants in emulsion polymerization to prepare freeze-thaw stable emulsions and the use of the resulting compositions.

(2) The invention provides reactive surfactants having the following formulas:

(3) ##STR00005##
where R=CH.sub.3, CH.sub.2CH.sub.3, C.sub.6H.sub.5, or C.sub.14H.sub.29; n=1, 2, or 3; x is 2-10, y is 0-200, z is 4-200, more preferably from about 5 to 60, and most preferably from about 5 to 40; Z can be either SO.sub.3.sup. or PO.sub.3.sup.2, and M.sup.+ is Na.sup.+, K.sup.+, NH.sub.4.sup.+, or an alkanolamine;

(4) ##STR00006##
where R=CH.sub.3, CH.sub.2CH.sub.3, C.sub.6H.sub.5, or C.sub.14H.sub.29; n=1, 2, or 3; x is 2-10, y is 0-200, z is 4-200, more preferably from about 5 to 60, and most preferably from about 5 to 40;

(5) ##STR00007##
where R.sub.1 is a C.sub.10-24 alkyl, alkaryl, alkenyl, or cycloalkyl, R.sub.2=CH.sub.3, CH.sub.2CH.sub.3, C.sub.6H.sub.5, or C.sub.14H.sub.29; x is 2-10, y is 0-200, z is 4-200, more preferably from about 5 to 60, and most preferably from about 5 to 40; and Z can be either SO.sub.3.sup. or PO.sub.3.sup.2, and M.sup.+ is Na.sup.+, K.sup.+, NH.sub.4.sup.+, or an alkanolamine; and

(6) ##STR00008##
where R.sub.1 is a C.sub.10-24 alkyl, alkaryl, alkenyl, or cycloalkyl, R.sub.2=CH.sub.3, CH.sub.2CH.sub.3, C.sub.6H.sub.5, or C.sub.14H.sub.29; x is 2-10, y is 0-200, z is 4-200, more preferably from about 5 to 60, and most preferably from about 5 to 40.

(7) The reactive surfactants are manufactured by reacting one equivalent of either the di- or tri-styrenated phenol or other hydroxyl containing materials with 2 or more equivalents of allyl glycidyl ether in an autoclave using potassium hydroxide catalyst at a temperature in the range of 100-110 C to produce an adduct having at least two equivalents of allyl glycidyl ether. The resulting adduct is then reacted with an alkylene oxide, mixtures of alkylene oxides and styrene oxide in the presence of a basic catalyst such as potassium hydroxide or an alkali metal alkoxide such as sodium or potassium methoxide.

(8) More specifically the process for alkoxylation includes the steps of: adding the catalyst to the organic compound containing at least one hydroxyl group; heating and pressurizing a reactor containing the hydroxyl containing organic compound; supplying alkylene oxide to said organic compound and catalyst at a process temperature of between 50 and 250 C. and at a pressure of between 100 and 700 kPa and isolating the alkoxylation products.

(9) The alkylene oxides useful for the alkoxylation reaction are selected from the group consisting of ethylene oxide, propylene oxide, butylenes oxide, C.sub.5-C.sub.18 oxides and styrene oxide. The alkylene oxide groups may be arranged at random or in blocks. Particular preference is given to block arrangements with fairly hydrophobic groups such as propylene oxide or, butylene oxide. The ratio of the molar amounts of the ethylene oxide groups to the other hydrophobic alkylene oxide groups is adjusted as necessary to achieve the desired properties.

(10) The performance properties of the novel reactive surfactants of the invention may be optimized for a specific application by appropriate modification such as the degree of alkoxylation and the different alkylene oxides that are used, and the choice of group used as an end cap. The interplay between these factors appears to be complex and is not well-understood. However, it is clear that manipulation of these variables allows access to materials which can perform as excellent emulsifiers.

(11) The present invention is also directed towards the emulsion polymerization of ethylenically unsaturated monomers in the presence of an anionic surfactant of formula (I)

(12) ##STR00009##
where R=CH.sub.3 or CH.sub.2CH.sub.3, n=1, 2, 3; x is 2-10, y is 0-200, z is 4-200 more preferably from about 5 to 60, and most preferably from about 5 to 40; Z can be either SO.sub.3.sup. or PO.sub.3.sup.2, and M.sup.+ is Na.sup.+, K.sup.+, NH.sub.4.sup.+, or an alkanolamine.

(13) The present invention also provides emulsion polymerization of ethylenically unsaturated monomers in the presence of a nonionic surfactant of formula (II)

(14) ##STR00010##
where R=CH.sub.3 or CH.sub.2CH.sub.3, n=1, 2, 3; x is 2-10, y is 0-200, z is 4-200 more preferably from about 5 to 60, and most preferably from about 5 to 40.

(15) In another embodiment, the present invention is further directed towards the emulsion polymerization of ethylenically unsaturated monomers in the presence of a surfactant of formulae (III) or (IV).

(16) ##STR00011##
where R.sub.1 is a C10-24 alkyl, alkaryl, alkenyl, or cycloalkyl, R.sub.2=CH.sub.3, CH.sub.2CH.sub.3, C.sub.6H.sub.5, or C.sub.14H.sub.29; x is 2-10, y is 0-200, z is 4-200, more preferably from about 5 to 60, and most preferably from about 5 to 40. Z can be either SO.sub.3.sup. or PO.sub.3.sup.2, and M.sup.+ is Na.sup.+, K.sup.+, NH.sub.4.sup.+ or an alkanolamine;

(17) ##STR00012##
where R1 is a C10-24 alkyl, alkaryl, alkenyl, or cycloalkyl, R.sub.2=CH.sub.3, CH.sub.2CH.sub.3, C.sub.6H.sub.5, or C.sub.14H.sub.29; x is 2-10, y is 0-200, z is 4-200, more preferably from about 5 to 60, and most preferably from about 5 to 40.

(18) The compounds of formulas (I)-(IV) may be used separately or in combination in the emulsion polymerization or further in combination optionally in the presence of other surfactants selected from the group consisting of nonionic, anionic, cationic and zwitterionic surfactants. When used in combination, the ratio of compounds of formulae (I) to (IV) is not limited but is dictated by the desired emulsion properties. Surfactants of formulas (I) to (IV) may also be used in combination with other surfactants that are commonly used in the art. When used in combination, the ratio of surfactants is not specific but is commonly optimized based on the nature of the ethylenically unsaturated monomers present in a given formulation.

(19) The total amount of surfactants of formulas (I) to (IV) that may be used in the present invention is preferably from about 0.1% to about 20% based on total weight of the monomer, more preferably from about 0.2% to about 10%, and most preferably from about 0.5% to about 7% based on the total weight of the monomer. The compounds of formulas (I) to (IV) may also be used in combination with conventional surfactants in order to improve emulsion properties.

(20) Other surfactants that are commonly used in the emulsion polymerization process include both anionic and nonionic molecules. Commonly utilized anionic surfactants in the emulsion polymerization process include sodium alkylbenzene sulfonates, alkyldiphenyloxide disulfonates, ethoxylated alkylphenol sulfates and phosphates, alkyl sulfosuccinates, and sulfates and phosphates of fatty alcohols, etc. Commonly utilized nonionic surfactants include linear and branched alcohol ethoxylates, and alkylphenol ethoxylates, particularly octylphenol ethoxylates. When used in combination with other surfactants the ratios are not limited but are also dictated by the desired emulsion properties.

(21) Suitable monomers that may be polymerized by the practice of the present invention include numerous ethylenically unsaturated monomers such as vinyl monomers or acrylic monomers. Typical vinyl monomers suitable for use in accordance with the present invention include, but are not limited to, vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate, etc; vinyl aromatic hydrocarbons such as styrene, methyl styrenes, other vinyl aromatics such as vinyl toluenes, vinyl napthalenes, divinyl benzene, etc. Halogenated vinyl monomers such as vinyl chloride, vinylidene chloride, etc. may also be used.

(22) Suitable acrylic monomers which may be used in accordance with the present invention comprise compounds with acrylic functionality such as alkyl acrylates and methacrylates, acrylate acids and methacrylate acids as well as acrylamides and acrylonitirle. Typical acrylic monomers include, but are not limited to methyl acrylate and methyl methacrylate, ethyl, propyl, and butyl acrylate and methacrylate, benzyl acrylate and methacrylate, cyclohexyl acrylate and methacrylate, decyl and dodecyl acrylate and methacrylate, etc. Other typical acrylic monomers include hydroxy alkyl acrylates and methacrylates such as hydroxypropyl and hydroxyethyl acrylate and methacrylate, acrylic acids such as methacrylic and acrylic acid, and amino acrylates and methacrylates. It will be recognized by those familiar with the art that other unsaturated monomers which are suitable for free radical addition polymerization may also be used in accordance with the present invention.

(23) Numerous free radical forming compounds are utilized as catalysts in the emulsion polymerization process. Typically compounds used as catalysts are those that from free radicals via thermal decomposition, referred to in the art as thermal initiators or combinations of compounds that form free radicals via oxidation/reduction reactions. Such catalysts are combinations of an oxidizing agent and a reducing agent and are commonly referred to in the art as redox initiators. Either thermal or redox catalysts may be used in the practice of the present invention.

(24) Typical catalysts utilized as thermal initiators include persulfates, specifically potassium persulfate, sodium persulfate, ammonium persulfate and the like. Typical redox initiators include combinations of oxidizing agents or initiators such as peroxides, specifically benzoyl peroxide, t-butyl hydroperoxide, lauryl peroxide, hydrogen peroxide, 2,2-diazobisiso-butyronitrile, and the like. Typical reducing agents include sodium bisulfite, sodium formaldehyde sulfoxylate, sodium hydrosulfite, and ascorbic and isoascorbic acid. The catalyst or initiator is employed in an amount preferably from 0.1 to 3 weight percent of the total monomer weight, and most preferably from about 0.1 to 1 weight percent of the total monomer charge.

(25) Other additives or components which are known to those skilled in the art may also used in accordance with the present invention. These include chain transfer agents, which are used to control molecular weight, additives to adjust pH, and compounds utilized as protective colloids which provide additional stability to the latex particles.

(26) The typical ingredients used in an emulsion polymerization are listed in the following generalized recipe:

(27) TABLE-US-00001 Component %-Wet Basis Monomers 30-50 Surface-active agents 1-3 Protective colloid 0-3 Initiator 1-3 Modifier 0-1 Buffer 0-1 Water 50-70

(28) The emulsifiers suspend monomer droplets and polymer particles. Modifiers may be aldehydes, mercaptans or chlorinated hydrocarbons that control the polymerization reaction restricting cross-linking and controlling the molecular weight. Protective colloids, such as polyvinyl alcohol or methyl cellulose, are used to stabilize the final latex. Buffer salts control the pH of the emulsion polymerization batch. These salts, such as phosphates, citrates, acetates and carbonates, are important because pH affects reaction rate, particle size and other reaction conditions.

(29) In some cases the monomer emulsion is seeded with polymer particles. The purpose of seeded emulsion polymerization is to avoid the uncertainties of the particle initiation stage, obtain better batch-to-batch reproducibility, and give a stable latex of the desired particle size. The reasons for polymerizing in water include: more rapid polymerization than bulk polymerization at the same temperature with a greater average molecular weight; good heat transfer in water with better control of heat of polymerization; all of the monomer is consumed in the polymerization and the resulting latex can be used directly in coating applications; and the aqueous phase lowers the overall viscosity of the emulsion.

(30) The monomer emulsion is made up of water-immiscible monomer droplets stabilized by surfactant molecules, empty micelles (colloidal surfactant vesicles) and monomer-swollen micelles. The monomer droplets can range in size from less than one micrometer to ten micrometers. The size of micelles is about 10 to 15 nanometers. During the reaction, the monomer molecules diffuse from the droplet reservoirs to the micelles where polymerization takes place. The polymer chains grow in the micelles. As polymerization proceeds, the monomer droplets decrease in size and eventually disappear. When the polymer particles become large, the surfactant molecules in the micelles suspend the polymer particles. The final polymer particles grow to a size range of a few tenths of a micrometer up to one micrometer. The physical character of the final polymer depends on the temperature of reaction, the formulation and the manipulation of the reaction conditions, such as when and how much of the ingredients are added to the reactor.

(31) A homogenizer is used in emulsion polymerization to emulsify the monomer into the premix to the reactor. Of all the emulsion monomers, vinyl chloride polymerization is the one that most commonly uses homogenizers to prepare the mix. In a typical process the ingredients to make the polymer are added in the appropriate sequence to an evacuated, agitated, pressurized tank (pressurized with nitrogen gas). After mixing the ingredients and adjusting the temperature of the mix, the emulsion is homogenized to produce the desired monomer droplet size. The homogenizing pressure may be in the range of 1000 to 5000 psi, depending on the monomer and the required droplet size of the monomer reservoir. This monomer droplet size can affect the physical character of the final latex particles. From the homogenizer the emulsion goes to the reactor, where polymerization occurs at a controlled temperature, until the desired conversion is achieved. After completion of the reaction, the latex is cooled and removed from the reactor.

(32) Any other of the conventional methods employed in the emulsion polymerization process may also be used in accordance with the present invention. These include both standard and pre-emulsion monomer addition techniques as well as staged monomer addition.

EXAMPLES

Example 1

(33) Distyrenated phenol (DSP) (694 g, 1 equivalent) was added to a stainless steel autoclave along with allyl glycidyl ether (AGE) (494 g, 2 equivalents) and potassium hydroxide KOH (2.3 g) and the autoclave sealed and heated to 105 C. When all of the AGE was consumed, the reaction mass was cooled, and the product discharged. This is AGE 2 DSP adduct.

(34) 1680 g of this AGE 2 DSP adduct (1 equivalent) was added to another autoclave and heated to 105 C. Ethylene oxide (2026 g, 15 equivalents) was then added over the course of several hours. After all of the EO was consumed, the reaction mass was cooled and the catalyst neutralized with the addition of a small amount of acid. This material is Example 1. This material is also referred to as ERS 1617. This material is also known as ERS 1617.

Example 1A

(35) Distyrenated phenol (DSP) (1388 g, 2 equivalent) was added to a stainless steel autoclave along with allyl glycidyl ether (AGE) (988 g, 4 equivalents) and potassium hydroxide KOH (4.6 g) and the autoclave sealed and heated to 105 C. When all of the AGE was consumed, the reaction mass was cooled, and the product discharged. This is AGE 2 DSP adduct.

(36) 3360 g of this AGE 2 DSP adduct (2 equivalents) was added to another autoclave and heated to 105 C. Ethylene oxide (4052 g, 30 equivalents) was then added over the course of several hours. After all of the EO was consumed, the reaction mass was cooled and the catalyst neutralized with the addition of a small amount of acid.

Example 1B

(37) Distyrenated phenol (DSP) (347 g, 0.5 equivalent) was added to a stainless steel autoclave along with allyl glycidyl ether (AGE) (247 g, 1 equivalents) and potassium hydroxide KOH (1.15 g) and the autoclave sealed and heated to 105 C. When all of the AGE was consumed, the reaction mass was cooled, and the product discharged. This is AGE 2 DSP adduct.

(38) 940 g of this AGE 2 DSP adduct (0.5 equivalent) was added to another autoclave and heated to 105 C. Ethylene oxide (1013 g, 7.5 equivalents) was then added over the course of several hours. After all of the EO was consumed, the reaction mass was cooled and the catalyst neutralized with the addition of a small amount of acid.

Example 1C

(39) Distyrenated phenol (DSP) (2776 g, 4 equivalent) was added to a stainless steel autoclave along with allyl glycidyl ether (AGE) (1976 g, 8 equivalents) and potassium hydroxide KOH (9.2 g) and the autoclave sealed and heated to 105 C. When all of the AGE was consumed, the reaction mass was cooled, and the product discharged. This is AGE 2 DSP adduct.

(40) 6720 g of this AGE 2 DSP adduct (4 equivalents) was added to another autoclave and heated to 105 C. Ethylene oxide (8104 g, 60 equivalents) was then added over the course of several hours. After all of the EO was consumed, the reaction mass was cooled and the catalyst neutralized with the addition of a small amount of acid.

Example 2

(41) Example 1 was sulfated with sulfamic acid in a glass reactor equipped with a stirrer, thermometer, and reflux condenser by heating to 120 C until the % sulfate was >90%. The product, Example 2, was isolated as the ammonium salt. The product is also known as ERS 1618.

Example 2A

(42) Three moles of Example 1 was phosphated with one mole of phosphorus pentoxide (P.sub.2O.sub.5) in a glass reactor equipped with a stirrer, thermometer, and reflux condenser by heating to 70 C until the reaction was complete. The product phosphoric acid ester, a mixture of mono- and diesters, was neutralized with aqueous ammonium hydroxide. The product was isolated as the ammonium salt in aqueous solution.

(43) In a procedure similar to Examples 1, 2, or 2A, examples 2B to 2Vwere prepared:

Examples 2B-2V

(44) TABLE-US-00002 Example AGE EO Terminal No. Hydrophobe (equivalents) (equiv) group 2B DSP 1 16 OH 2C DSP 1 16 OSO3.sup. NH4.sup.+ 2D DSP 2 15 OSO3.sup. NH4.sup.+ 2E DSP 2 15 OPO3.sup. NH4.sup.+ 2F DSP 2 15 OPO3.sup. K.sup.+ 2G Tridecyl alcohol 1 17 OH 2H Tridecyl alcohol 1 17 OSO3.sup. NH4.sup.+ 2I Tridecyl alcohol 2 36 OH 2J Tridecyl alcohol 2 36 OPO3.sup. NH4.sup.+ 2K Nonylphenol 2 4 OH 2L Nonylphenol 2 4 OSO3.sup. NH4.sup.+ 2M Nonylphenol 2 38 OH 2N Nonylphenol 2 38 OSO3.sup. NH4.sup.+ 2O DSP 2 15 OPO3.sup. NH4.sup.+ 2P DSP 1 5 OH 2Q DSP 1 5 OSO3.sup. NH4.sup.+ 2R DSP 2 5 OSO3.sup. NH4.sup.+ 2S TSP 1 10 OH 2T TSP 1 10 OSO3.sup. NH4.sup.+ 2U TSP 2 10 OH 2V TSP 2 10 OSO3.sup. NH4.sup.+

Examples 3-65

(45) 1) Surfactants

(46) a) Example 1POE(15) {DSP/2 AGE} nonionic (ERS 1617) b) Example 2POE(15) {DSP/2 AGE} Sulfate, ammonium salt (ERS 1618) c) E-Sperse 704POE(20) DSP Sulfate, ammonium salt available from Ethox Chemicals, Greenville, S.C., USA d) E-Sperse 703POE(20) DSP available from Ethox Chemicals, Greenville, S.C., USA e) ERS 1689POE (10) TSP available from Ethox Chemicals, Greenville, S.C., USA f) SLS (sodium lauryl sulfate)

(47) DSP is a mixture of mono-, di- and tristyrenated phenols with distyrenated phenol the major component; TSP is tristyrenated phenol; AGE is allyl glycidyl ether; POE is poly(oxyethylene) and the number following is the equivalents of added ethylene oxide

(48) These surfactants were used to make emulsion polymers with a Tg of either 15 C, 5 C, 5 C, or 35 C. The Tg was adjusted by varying the amount of butyl acrylate used in the recipe according to the Fox equation for estimating the Tg of copolymers. The general recipe is as follows:

(49) TABLE-US-00003 TABLE 1 Latex Recipe Material Weight Purity Solids Initial Charge Water (DI) 337.3 0.00 0.0 Sodium Bicarbonate 6.00 1.00 6.0 Seed Latex - 190 nm 107.0 0.31 32.6 Sub Total 450.3 38.6 Initial Oxidizer Ammonium Persulfate 2.30 1.00 2.3 Water (DI) 60.00 0.00 0.0 Sub Total 62.3 2.3 Monomer Feed 1 Water (DI) 286.30 0.00 0.0 1.sup.st Surfactant 17.40 0.50 8.7 2.sup.nd surfactant 8.68 1.00 8.7 Butyl Acrylate 450.0 1.00 450.0 Methyl Methacrylate 350.0 1.00 350.0 Methacrylic Acid 8.3 1.00 8.30 Sub Total 1120.7 825.7 Delayed Oxidizer Ammonium Persulfate 2.30 1.00 2.3 Water 56.00 0.00 0.0 Sub Total 58.30 2.3 Post Oxidizer t-butylhydroperoxide 0.90 0.70 0.6 Water 23.00 0.00 0.0 Sub Total 23.90 0.6 Post Reducer Sodium metabisulfite 0.90 1.00 0.9 Water 23.00 0.00 0.0 Sub Total 23.90 0.9 Post Addition NH4OH (28% NH3) 0.0 0.00 pH = 8 Water (DI) 0.0 0.00 0.0 Sub Total 0.0 0.0 TOTAL SUM 1739 870 Feed rates (mls/min) Start Stop Rate Monomer Feed 1 (rate1) 0 30 2.00 Monomer Feed 1 (rate1) 30 210 5.89 Delayed Oxidizer 0 210 0.28 Post Oxidizer 240 300 0.40 Post Reducer 240 300 0.40 Seed conc on monomer 3.95% Expected properties Total Solids (%) 50.0% Seed Surf on solids 0.19% Anionic surf on solids 1.00% Nonionic surf on solids 1.00% Total surf on solids 2.18% Oxidizer on solids 0.53% Post oxidizer on solids 0.07% Post reducer on solids 0.10% MAA on solids 0.95%
Acrylic Latex Procedure:

(50) Add initial oxidizer to the initial charge in a stirred vessel at 75 C. When mixed, begin adding the monomer feed to stirred vessel. At the end of monomer feed, continue stirring for 30 minutes, and then begin post reducer and oxidizer feeds. Cool down to at least 30 C, adjust pH with ammonium hydroxide, and measure properties.

(51) The surfactants are designated as primary or secondary. The primary surfactants are listed in the 1.sup.st surfactant column in Table 2 below. Secondary surfactants are alternate surfactants that can be added during the polymerization or post added. If they were post added after the polymerization was complete, the word blend is added in the tables below. The particle size data (Mv volume) was obtained using a Microtrac laser diffraction particle size analyzer.

(52) Experimental Procedure for Freeze Thaw Test:

(53) In order to assess rapidly a large number of latexes for freeze/thaw stability, the latexes were put into clear plastic 3510 mm petri dishes with covers. The samples were placed into a negative 18 C freezer; the samples froze within 3 hours. After removal from the freezer, they were allowed to thaw at room temperature over one hour. A sample was judged to be freeze/thaw stable after that cycle if no visible change in its viscosity or consistency had occurred. If the sample (latex or paint) was unchanged after a cycle, it was placed back into the freezer to start another cycle. Testing was complete whenever a sample failed or survived five freeze/thaw stability cycles.

(54) TABLE-US-00004 TABLE 2 2nd Surfactant Number of Tg Surfactant (during Freeze Example (deg (during polymerization or Thaw Latex C.) polymerization) % blended after) % Cycles Mv 3 5 E-Sperse 704 1 0 168 4 5 E-Sperse 704 1 0 289 5 5 E-Sperse 704 1 0 173 6 15 E-Sperse 704 1 0 146 7 5 E-Sperse 704 1 E-Sperse 703 blend 2 0 168 8 5 E-Sperse 704 1 E-Sperse 703 blend 2 0 289 9 5 E-Sperse 704 1 E-Sperse 703 blend 2 0 173 10 15 E-Sperse 704 1 E-Sperse 703 blend 1 0 146 11 15 E-Sperse 704 1 E-Sperse 703 blend 2 5 146 12 5 E-Sperse 704 1 ERS 1689 blend 1 0 173 13 5 E-Sperse 704 1 ERS 1689 blend 2 0 173 14 5 E-Sperse 704 1 Example 1 1 0 202 15 5 E-Sperse 704 1 Example 1 2 0 190 16 5 E-Sperse 704 1 Example 1 1 5 171 17 5 E-Sperse 704 1 Example 1 2 5 177 18 15 E-Sperse 704 1 Example 1 1 5 220 19 15 E-Sperse 704 1 Example 1 2 5 177 20 5 Example 2 1 ERS 1689 1 0 180 21 5 Example 2 1 ERS 1689 + 1689 blend 2 5 180 22 5 Example 2 1 1% 703 blend 0 23 5 Example 2 1 2% 703 blend 0

(55) Examples 3-6 above show that E-Sperse 704 at 1% did not impart any freeze/thaw stability to any latex, even the high Tg (15 C) latex.

(56) Examples 7-11 show that the post polymerization addition of E-Sperse 703 to the latexes of Examples 3-6 only improved freeze/thaw stability in the 15 C Tg latex. This shows that the higher Tg latex is easier to stabilize.

(57) Examples 12 and 13 show that the addition of 1 or 2% of ERS 1689, known to be an excellent freeze/thaw stability additive, was insufficient to impart freeze/thaw stability to the E-Sperse 704 5 C Tg latex.

(58) Examples 14-19 show that the use of 1% Example 1 as the second polymerization surfactant was sufficient to impart at least five cycles of freeze/thaw stability to the 5 C and 15 C latexes. Example 1 has a structure similar to E-Sperse 703 (POE 20 DSP) but has two reactive moieties on the hydrophobe end of the polymer. The reactivity of Example 1 appears to result in improved freeze/thaw stability.

(59) Examples 20 and 21 show that Example 2, an anionic reactive surfactant, in combination with ERS 1689, gave good freeze/thaw stability while E-Sperse 704 (non-reactive, but similar structure (POE 20 DSP sulfate)) in the same combination with ERS 1689 (Example 13) did not.

(60) Examples 22 and 23 show that Example 2, an anionic surfactant, in combination with E-Sperse 703, did not give good freeze/thaw stability. Presumably, ERS 1689 is a better freeze/thaw stability additive than E-Sperse 703.

(61) In the study in Table 3 below, latexes were made according to the above procedure at a Tg of 5 C with SLS and E-Sperse 704 as primary surfactants in order to compare their contribution to freeze/thaw stability when Example 1 was used as the secondary surfactant. This was done to determine if E-Sperse 704 imparted any extra freeze/thaw stability characteristics as compared to the commonly used surfactant, SLS.

(62) TABLE-US-00005 TABLE 3 Freeze/thaw stability comparison of SLS and E-Sperse 704 Primary Secondary Surfactant Freeze Particle Example Calculated Surfactant (during polym. Thaw size (nm) latex Tg (deg C.) (during polym) % or blended after) % Cycles Mv 24 5 E-Sperse 704 1 0 173 25 5 E-Sperse 704 1 Example 1 0.5 0 166 26 5 E-Sperse 704 1 Example 1 1 5 171 27 5 SLS 1 0 145 28 5 SLS 1 Example 1 0.5 0 164 29 5 SLS 1 Example 1 1 5 161
Since freeze/thaw stability is obtained at 1% EXAMPLE 1 in both the E-Sperse 704 and SLS recipes, it is readily apparent that E-Sperse 704 does not confer added freeze/thaw stability characteristics over SLS, at least not as the primary surfactant in these recipes.
Comparison of E-Sperse 704, Example 2, and SLS for Freeze Thaw Resistance:

(63) Latexes with Example 2 as the primary surfactant produce freeze/thaw stability with ERS 1689 (Table 4). This occurs both with ERS 1689 at 2% added during the reaction and when half of the surfactant is blended in after the reaction. The use of SLS as the primary surfactant does not confer freeze/thaw stability when ERS 1689 is employed as the secondary surfactant.

(64) TABLE-US-00006 TABLE 4 Effect of F/T on E-Sperse 704, Example 2, and SLS (ERS 1689 as secondary surfactant) Primary Secondary Surfactant Latex Calculated Surfactant (during polym. or blended Freeze Thaw Particle size Reference Tg (deg C.) (during polym) % after) % Cycles (nm) Mv 30 5 E-Sperse 704 1 ERS 1689 2 0 177 31 5 Example 2 1 ERS 1689 1 0 180 32 5 Example 2 1 ERS 1689 2 5 33 5 Example 2 1 ERS 1689 + 1689 blend 2 5 180 34 5 SLS 1 ERS 1689 2 0 162

(65) Upon examining the above data, it is apparent that the only time where freeze/thaw stability is obtained is when either Example 1 or Example 2 is used at concentrations of at least 1% in combination with other surfactants. It is believed that the capability of these materials to polymerize into the polymer backbone, along with their unique structure, allows for superior freeze/thaw stability characteristics in latexes.

(66) Comparison of Surfactants for Freeze Thaw Resistance at Various Tg in Latexes and in Paint

(67) Paint Formulation:

(68) The ingredients in Table 5 were added to a stainless steel beaker in the order listed using a high-speed disperser. A good grind was obtained. Next the letdown was made (except latex) using low speed on the same disperser. Very small volume mixtures of the paint base with latex were then made (25 g). The paint was mixed for a further 15 minutes.

(69) TABLE-US-00007 TABLE 5 Flat Paint Formulation Grind Pounds Gallons Flat Paint Recipe Water 100 11.9 Cellosize QP 4400 1 0.1 Ammonia (28%) 0.5 0.1 Water 40 4.8 Tamol 165A 17.6 2 TRITON CF-10 2.2 0.3 DrewPlus L-108 1 0.1 Ti-Pure R-902+ 206 6.2 Minex 4 29 1.3 Minex 10 143 6.5 Grind Sub-total 540.3 33.3 Letdown Water 40 4.8 Experimental latex (50% Wt) 375 43 ROPQAUE Ultra E 30% wt 48.7 5.7 DrewPlus L-108 1.5 0.2 Ammonia (28%) 3 0.4 Total 1096 100.1 Formula Values: Volume Solids: 37% Density: 11.2 Weight Solids: 51% pH: 8.3-9.3 Gloss: 60 degree 5 85 degree 7 PVC: 46% VOC: <2 g/L
Cellosize QP is a cellulosic polymer thickener available from the Dow Chemical company. Tamol 165A is a pigment dispersant available from the Dow Chemical company. Triton CF-10 is a surfactant available from DOW Chemical. DrewPlus L-108 is a foam control agent available from Ashland Specialty Ingredients. Ti-Pure R-902 is a titanium dioxide pigment available from Dupont. Minex 4 and 10 are mineral oxides available from Unimin Specialty Minerals. ROPAQUE Ultra E is a pigment available from DOW Chemical.

(70) Tables 6, 7, 8, and 9 below show the effect on freeze/thaw stability of various combinations of anionic and nonionic surfactants on latexes with various Tg and the paints comprising them. For each example, the combination of either reactive anionic surfactant (Example 2) or non-reactive anionic surfactant (E-Sperse 704), and reactive nonionic surfactant (Example 1) or non-reactive nonionic surfactant (ERS 1689) is noted. The values in these columns are the weight percentages of each surfactant required to achieve five cycles of freeze/thaw stability in the paint comprising the example latex. All latexes in a table were prepared from the same recipe, varying only in the amounts and type of surfactants used.

(71) TABLE-US-00008 TABLE 6 Examples 35-42 Tg 5 C. Latex and Flat Paints Latex Paint Example E-Sperse ERS FT FT latex Example 2 704 Example 1 1689 Tg Mv cycles cycles 35 0.25 0 0.25 0 5 169 0 5 36 0.50 0 0.50 0 5 273 5 5 37 1 0 0 0 5 150 0 5 38 1 0 0 2 5 175 5 5 39 1 0 0 3 5 150 5 5 40 0 1 1 0 5 171 5 5 41 0 1 0 1 5 173 0 5 42 0 1 0 5 5 173 5 5

(72) Freeze/thaw stability may be realized at much lower surfactant usage levels when reactive anionic and nonionic surfactants are used in combination. Example 35 (all reactive surfactant) requires one quarter of the surfactant loading of Example 41 (no reactive surfactant), and similarly, Example 36 requires 1.0% total surfactant whereas Example 42 requires 6% total surfactant.

(73) Advantages in surfactant reduction may also be realized when either an anionic reactive or reactive nonionic surfactant are used in combination with a nonreactive surfactant, though not as great as when a fully reactive surfactant system is used. For example, paint freeze/thaw stability is obtained when 1.0% of Example 2 surfactant is used (Example latex 37) compared with 2.0% required for E-Sperse 704 (Example latex 41). In latex only testing, these same surfactants required 3.0% (Ex latex 38) compared to 6% (Ex latex 42). Similarly, comparing the latex in Example 40 with that of Example 42, both of which were prepared with E-Sperse 704 non-reactive anionic surfactant, Example 40 required only 1% of the reactive nonionic (2% total surfactant) whereas the Example 42 latex required 5% non-reactive nonionic (6% total surfactant).

(74) The paint data in Table 6 shows that significantly less surfactant is needed to produce freeze/thaw stability in flat latex paints than in the neat latex. This is expected since it is believed that latex/latex interactions cause freeze/thaw failure and with highly stabilized pigments that are present in paint interfering with latex/latex interactions, failure is less likely.

(75) TABLE-US-00009 TABLE 7 Examples 43-49 Tg 5 Latex and Paints Latex Paint Example E-Sperse ERS FT FT latex Example 2 704 Example 1 1689 Tg Mv cycles cycles 43 1 0 1 0 5 177 0 5 44 1 0 2 0 5 198 5 5 45 1 0 0 1 5 152 0 5 46 1 0 0 4 5 152 5 5 47 0 1 0 0 5 157 0 0 48 0 1 0 1 5 157 0 5 49 0 1 0 4 5 157 4 5

(76) The paint data in Table 7 shows that more surfactant is needed to produce freeze/thaw stability in flat latex paints than in the higher Tg latexes in Table 6. Again, the paint prepared from latex incorporating only reactive surfactants (Example latex 44) requires much less total surfactant than the paint incorporating a latex with non-reactive surfactants (Example 49). Examples 44 and 46 show that the reactive nonionic surfactant is much more effective at imparting freeze/thaw stability than the non reactive nonionic.

(77) TABLE-US-00010 TABLE 8 Examples 50-58 Tg 15 Latex and Paints E- Latex Paint Example Sperse ERS FT FT latex Example 2 704 Example 1 1689 Tg Mv cycles cycles 50 0.50 0 0.50 0 15 187 0 0 51 0.50 0 0.50 2.5 15 187 0 5 52 0.50 0 0.50 4 15 187 5 5 53 1 0 0 0 15 169 0 0 54 1 0 0 3 15 169 0 5 55 1 0 0 5 15 169 5 5 56 2 0 2 0 15 169 5 5 57 0 1 0 3 15 157 0 5 58 0 1 0 4 15 157 5 5

(78) The paint data in Table 8 shows that more surfactant is needed to produce freeze/thaw stability in flat latex paints at 15 C Tg than in the higher Tg latexes in Tables 6 or 7. Again, the paint prepared from latex incorporating only reactive surfactants (Example latex 56) requires less total surfactant than the paint incorporating latex with non-reactive surfactants (Example 58).

(79) TABLE-US-00011 TABLE 9 Examples 59-65 Tg 35 Latex and Paints E- Latex Paint Example Sperse ERS FT FT latex Example 2 704 Example 1 1689 Tg Mv cycles cycles 59 2 0 2 0 35 176 0 5 60 1 0 3 0 35 202 0 5 61 1 0 5 0 35 187 5 5 62 1 0 0 4 35 156 0 5 63 1 0 0 5 35 156 5 5 64 0 1 0 4 35 160 0 5 65 0 1 0 7 35 160 5 5 Example 2 reactive anionic required 6% total surfactant compared to 8% with E-Sperse 704 nonreactive anionic. The full reactive surfactant system of Example 61 used less total surfactant (6% compared to 8%) than the non-reactive system (Example 65).

(80) The content of all references cited in the instant specifications and all cited references in each of those references are incorporated in their entirety by reference herein as if those references were denoted in the text

(81) While the many embodiments of the invention have been disclosed above and include presently preferred embodiments, many other embodiments and variations are possible within the scope of the present disclosure and in the appended claims that follow. Accordingly, the details of the preferred embodiments and examples provided are not to be construed as limiting. It is to be understood that the terms used herein are merely descriptive rather than limiting and that various changes, numerous equivalents may be made without departing from the spirit or scope of the claimed invention.

(82) This application was filed on Oct. 21, 2012, by Isaac A. Angres, Reg. No. 29,765.