Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F2/00—Processes of polymerisation
  • C08F2/12—Polymerisation in non-solvents
  • C08F2/16—Aqueous medium
  • C08F2/22—Emulsion polymerisation
• • 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
  • C09D143/00—Coating compositions based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and containing boron, silicon, phosphorus, selenium, tellurium, or a metal; Coating compositions based on derivatives of such polymers
  • C09D143/04—Homopolymers or copolymers of monomers containing silicon
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F212/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring
  • C08F212/02—Monomers containing only one unsaturated aliphatic radical
  • C08F212/04—Monomers containing only one unsaturated aliphatic radical containing one ring
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
  • C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
  • C08F220/10—Esters
  • C08F220/12—Esters of monohydric alcohols or phenols

Definitions

• This invention relates to emulsion polymers and to paints and other coatings containing emulsion polymers.
• Water-based coatings and paints are well known and have been sold commercially for many years. These coatings and paints are based on emulsion polymers, which are referred to as latexes. In addition to the latex, these coatings usually contain additional ingredients such as pigments, opacifiers, coalescents and crosslinkers, among others.
• these water-based coatings and paints will contain a small quantity of an organic solvent. These solvents tend to be volatile and produce vapors when the coating or paint is applied. For environmental and safety reasons, it is desired to reduce the level of solvent and other volatile components in the water-based coatings and paints.
• Blocking refers to the tendency of the coating or paint to adhere to itself or to have a tacky surface after drying.
• Water-based coatings and paints need to form highly coalesced films when they are dried at their particular application temperature. To achieve this high degree of coalescence, the emulsion polymer must either have a T g below the application temperature, or else be used in conjunction with coalescing solvents. Both approaches usually lead to bad "blocking" properties of the coatings or paints. Polymers with a low T g usually cause the coating to exhibit poor "final” blocking properties, in that the polymer will block even when completely dried. Coatings formulated with coalescing solvents dry slowly and therefore exhibit poor "early" blocking characteristics for an extended period until drying is complete.
• the coating or paint must be able to resist damage caused by exposure to water and solvents such as are commonly present in household cleaners. Attempts to improve blocking resistance by blending hard components with soft components can lead to reduced resistance to water and/or solvents. It would therefore be desirable to provide an emulsion polymer which resists both early and final blocking, water spotting and spotting from common solvents such as ethanol. It would also be desirable to provide a coating or paint composition which is similarly resistant.
• this invention is an aqueous emulsion having an aqueous phase and a dispersed polymer phase, wherein the dispersed polymer phase comprises particles of a polymer of monomer mixture including
• said monomer mixture further comprises
• this invention is an aqueous emulsion having an aqueous phase and a dispersed polymer phase, wherein the dispersed polymer phase comprises particles of a polymer of monomer mixture including
• said monomer mixture further comprises at least 0.1 percent, based on the weight of all monomers, of a monomer having at least two ethylenically unsaturated, addition polymerizable groups;
• said monomer mixture is polymerized in two stages, in which monomers which together form a polymer having a T g of less than 25°C are polymerized in a first stage and monomer which together form a polymer having a T g of at least 60°C are polymerized in a second stage.
• this invention is a coating composition comprising the aqueous emulsion of the first aspect.
• the emulsion of this invention surprisingly exhibits excellent resistance to both early and final blocking, even when dried at temperatures well above the T g of the dispersed polymer particles. Moreover, this blocking resistance is not obtained at the expense of a significant loss of water and solvent resistance; this emulsion provides for adequate to excellent resistance to both water and ethanol/water mixtures.
• the aqueous emulsion of this invention includes a continuous aqueous phase and a dispersed polymer phase.
• the dispersed polymer phase is in the form of particles of a size such that they can remain stably dispersed in the aqueous phase.
• a suitable size range for the particles is from 40 nm to 350 nm in diameter ("diameter” here referring to the longest dimension of the particle), preferably 50 to 120 nm.
• the dispersed particles comprise a polymer which is prepared by polymerizing a mixture of monomers of at least three different types.
• mixture of monomers or “monomer mixture” means only that the polymer contains repeating units from each member of the mixture, but does not require that all the monomers must be mixed together before polymerizing, or that the monomers must all be polymerized simultaneously.
• the monomers may be polymerized all at one time, polymerized sequentially, polymerized in groups, or any combination of these.
• the monomer mixture contains at least 5.5 weight percent, up to 15 weight percent, of an ethylenically unsaturated functional monomer.
• the level of the functional monomer may be reduced to as low as 3.5 percent or 3 percent when the emulsion polymer is prepared in a two-stage polymerization reaction as described below.
• a "functional monomer" is one which contains a highly polar group.
• Such functional monomers include those containing one or more ionic groups, such as sulfonate or carboxylate groups, precursors of such ionic groups, such as sulfonic acid and carboxyl groups, and other highly polar groups which, although they are not ionic in character, impart high polarity to the monomer.
• Specific functional monomers useful in this invention include methacrylic acid, acrylic acid, fumaric acid, maleic acid, itaconic acid, succinic acid, hydroxyethyl methacrylate, hydroxyethyl acrylate, acrylamide, acrylonitrile, methacrylonitrile, acetoxy ethyl methacrylate, acetoxy ethyl acrylate, acetoacetoxy ethyl methacrylate, sodium styrene sulfonate, sodium 1-acrylamido-2-methylpropane sulfonate, sodium alkyl allyl sulfosuccinate (in which the alkyl group contains up to about 20 carbon atoms), and glycidyl methacrylate.
• Sulfonated monomers or monomers with a sulfosuccinate group, containing a long hydrocarbon chain (C 6 or higher, preferably up to C 20 ) often operate as a surfactant during the polymerization reaction; in that case, added surfactant may be minimized or unnecessary.
• a surfactant such as C 6 or higher, preferably up to C 20
• Those monomers containing acid groups may be used in the form of their salts, preferably salts with a monovalent cation, more preferably of an alkali metal or ammonium salt.
• those monomers containing acid salt groups may be used in the free acid form.
• the functional monomer mixture includes one or more monomers containing at least one carboxyl or carboxylate group or one or more monomers containing at least one sulfonic acid, sulfonate or sulfosuccinate group.
• monomers of both type are present.
• the sulfonate group is preferably in salt form, with the cation being monovalent and preferably an alkali metal or ammonium.
• the sulfonated monomer(s) constitutes at least 0.8 percent, preferably at least 1.5 percent, more preferably at least 2 percent, up to 10 percent, preferably up to 5 percent, more preferably up to 4 percent, based on the combined weight of all monomers.
• a monomer containing a carboxyl or carboxylate group When a monomer containing a carboxyl or carboxylate group is present, it constitutes at least 0.5 percent, preferably at least 1.5 percent, more preferably at least 2.5 percent, up to 10 percent, preferably up to 5 percent of the total weight of all monomers.
• the second type of monomer is one or more ethylenically unsaturated monomer(s) containing a silicon atom to which is bound at least one hydrolyzable group.
• the ethylenic unsaturation is bound to the silicon atom through a linkage which is not itself hydrolyzable.
• the monomer(s) of this type constitute at least about 0.5 percent, preferably from about 1.6 percent, more preferably at least about 2 percent, up to 10 percent, preferably up to 7 percent, more preferably up to 4 percent of the weight of all monomers.
• the monomers of the second type have at least one, preferably at least two, and more preferably three hydrolyzable groups bound to the silicon atom.
• Examples of such hydrolyzable groups include aceto groups and those in which the R group corresponds to methyl, ethyl, propyl, 1 -methylethyl or 1-methyl-2-methoxyethyl.
• Illustrative monomers of the second type include methacryloxypropyl trimethoxy silane, vinyl tris(1-methoxypropyl-2-oxy) silane, vinyl triethoxy silane, vinyl trimethoxysilane, ⁇ -methacryloxy propyl trimethoxy silane, or vinyl triacetoxysilane.
• the monomer mixture When less than 1.5 percent of the monomer of the second type is used, then the monomer mixture must also contain at least 0.1 percent of a monomer having at least two ethylenically unsaturated, addition polymerizable groups. In other cases, this last type of monomer is optional, but not required.
• This type of monomer may constitute up to 5 percent of the monomer mixture, preferably up to 1.5 percent. Examples of such monomers include divinylbenzene and ethylene glycol di methacrylate. Preferably, this monomer contains at least two ethylenically unsaturated groups of significantly differing reactivity, such as allyl methacrylate or allyl acrylate.
• the monomer contains ethylenically unsaturated groups of differing reactivity, it is possible to provide a polymer which can be post- crosslinked, because the more reactive monomer will polymerize as the polymer is prepared, but the less reactive unsaturated group will remain unreacted and available for reaction at a later time, such as during the curing of the polymer.
• the third type of monomer is one or more nonfunctionalized vinyl aromatic monomer(s), acrylic esters or methacrylic esters.
• nonfunctionalized it is meant that the monomer contains (1) no groups which cause the monomer to be highly polar (as defined above), (2) no groups other than a polymerizable group which react during the course of polymerization, and (3) no silicon atoms having hydrolyzable substituents.
• Suitable such monomers include styrene, ⁇ -methyl styrene, vinyl toluene, vinyl naphthalene, any of which can be inertly-substituted, such as with alkyl or alkoxyl groups; acrylic and methacrylic esters in which the ester group is C,-C 20 alkyl, preferably C 2 -C 8 alkyl, such as butyl acrylate, 2-ethylhexyl acrylate, butyl methacrylate, 1-ethylhexyl acrylate, methyl and methacrylate.
• the monomer or monomers of the third type can be selected to provide desirable properties to the polymer.
• the monomers can be selected so that the dispersed polymer particles have a T g within a desired range, or so that the polymer particles will form a film at a desired temperature.
• the third type of monomer is largely selected from "hard monomers” like styrene and/or methyl methacrylate and/or tertiary-butyl methacrylate
• the T g and the minimum film formation temperature (MFFT) of the resulting polymer tend to be high, such as, for example above 35°C, preferably above 60°C.
• the third type of monomer is largely selected from "soft monomers” like n-butyl acrylate and/or n-hexyl acrylate and/or n-heptyl acrylate and/or 2-ethyl hexyl acrylate, then the T g and MFFT tend to be lower, such as below 35°C, preferably below 15°C, more preferably less than or equal to 6°C.
• the T g and MFFT of the polymer particles may be adjusted to a desired value.
• the MFFT is measured by casting a 150 ⁇ m film of the emulsion on a heating plate that has a temperature gradient. The film is dried and the minimum temperature at which a coherent film is formed is recorded as the MFFT.
• the emulsion of this invention is conveniently prepared by polymerizing the monomer mixture just described in an emulsion polymerization in an aqueous phase.
• Such polymerization methods are well known and are described, for example, in Emulsions:
• the emulsion polymerization process includes mixing the monomers into a continuous aqueous phase under agitation sufficient to disperse the monomers into fine droplets. Unless one or more of the monomers has surface active characteristics, one or more surfactants are present in order to form micelles as reaction loci and to form a stable emulsion having discrete particles of desirable size.
• a free radical initiator or redox catalyst is usually employed to provide an acceptable rate of polymerization and a high conversion of monomers to polymer.
• the monomers may be added to the aqueous phase all at once in a batchwise operation, or all of a portion may be added continuously or in increments as the polymerization proceeds.
• the different monomers may be added at different times during the polymerization, or at varying relative rates at different times, or at the same relative rates throughout the polymerization.
• Seed polymer particles may be added at the start of the polymerization in order to help control the nucleation of particles and the size of the final polymer particles.
• the weight of the seed particles is preferably no greater than 2.0 percent of that of the monomer mixture; in such a case, the composition of the seed particles is ignored when calculating the amounts of the various monomer types in the monomer mixture.
• water, surfactant and optional seed particles are initially charged to a suitable reactor and heated to the desired polymerization temperature.
• the desired polymerization temperature depends on the particular catalyst and monomers employed, and typically ranges from 30°C to 100°C, preferably from 50°C to 100°C, more preferably from 60°C to 100°C.
• the initial charge to the reactor may include all or a portion of the monomer mixture.
• one or more streams is fed to the reactor.
• One of those streams contains the free radical initiator (or redox catalyst).
• the monomer mixture may be added in one or more separate streams.
• Additional surfactant may also be added, either as a separate stream or mixed with the catalyst or one or more of the monomers.
• the reactor contents are typically heated for a period to complete polymerization. Often, this post addition heating is conducted at a higher temperature.
• a two-stage polymerization process can be used.
• This two-stage process has the advantage of requiring a smaller amount of the functional monomer.
• monomers selected from one or more of the types previously described, which together from a polymer having a T g of 25°C or less are polymerized in a first stage.
• the monomers polymerized in the first stage may or may not contain a functional monomer, and may or may not contain the monomer containing a silicon atom having hydrolyzable substituents; all that is required is that the first stage monomers polymerize to form a polymer having the requisite T g .
• the monomers polymerized in the first stage can be mixed and polymerized, or may be fed into the reaction mixture as separate streams.
• One or more of the monomers polymerized in the first stage may be added as part of the initial charge to the reactor, with the remaining monomers in the first stage added as a stream.
• the first stage monomers are added, they are polymerized to a conversion of at least 70 weight percent, preferably at least 80 weight percent, and then the second stage monomers are added.
• the second stage monomers are selected from the types described before, and are chosen so that they form a polymer having a T g of at least 60°C.
• the second stage monomers may or may not contain a functional monomer, and may or may not contain the monomer containing a silicon atom having hydrolyzable substituents; all that is required is that the second stage monomers polymerize to form a polymer having the requisite T g .
• the functional monomers and the monomer containing the silicon atom having hydrolyzable substituents may be added in either the first stage, the second stage, or both.
• references to Tg are those obtained by differential scanning calorimetry (DSC) on a dried latex sample made by pouring one drop of latex into an aluminum crucible and drying for 12 to 20 hours at room temperature in a desiccator.
• the samples are evaluated using a Mettler DSC 30 calorimeter, scanning at a rate of 10°C/minute over a range of -40 °C to 110°C.
• the T g of the polymer formed in each stage can be determined by polymerizing the monomer or monomer mixture alone in a single stage polymerization process, and measuring the T g of the resulting polymer in the manner just described.
• the T g of a styrene/2-ethylhexyl acrylate mixture can be determined by polymerizing that mixture in a single-stage polymerization, and measuring the T g of the resulting polymer.
• reaction conditions such as temperature and free radical initiator
• A, B and N represent individual monomers in the mixture containing N monomers
• wA, wB and wN represent the weight fractions of monomers A, B and N, respectively
• T AN represents the T g of the polymer formed
• T g A, T g B and T g N represent the T g of homopolymers of monomers A, B and N, respectively.
• the amount of monomers added and polymerized is selected so that the resulting polymer emulsion has a desired solids content, and the copolymer particles have a desired size.
• the resulting emulsion has a solids content from 10 to 70 percent by weight, more preferably from 25 to 55 percent by weight, and the copolymer particles have a volume average diameter from 40 nm to 350 nm, preferably from 50 to 120 nm.
• Any surfactant which stabilizes the monomer mixture as discrete droplets and the subsequent copolymer as discrete particles in the aqueous phase can be used.
• the surfactant may be of the nonionic, anionic or amphoteric type.
• Exemplary surfactants include alkali metal alkyl carboxylates, polyoxyethylene alkyl phenols, linear alkyl sulfonates, alkyl aryl sulfonates, alkylated sulfosuccinates, C 6 -C 20 amine oxides, N,N-bis(carboxyl alkyl) and C 6 -C 20 alkyl amines.
• SIPONATETM A246L brand surfactant available from Rhone- Poulenc
• sodium dodecyl benzene sulfonate sodium lauryl sulfate
• disodium dodecyldiphenylether disulfone sodium dodecyl benzene sulfonate
• sodium lauryl sulfate sodium lauryl sulfate
• disodium dodecyldiphenylether disulfone N-octadecyl disodium sulfosuccinate, dioctyl sodium sulfosuccinate, N,N-bis-carboxyethyl lauramine
• sulfonated alkylated phenyl ethers such as DOWFAX * 2EP and DOWFAX * 2A1 (Trademark of The Dow Chemical Company and both are available from The Dow Chemical Company), are all suitable surfactants.
• the surfactant is advantageously used in an amount from
• Suitable free radical initiators include peroxy compounds such as peroxydisulfates (commonly known as persulfates), perphosphates, t-butyl hydroperoxide, cumene hydroperoxide and hydrogen peroxide. Ammonium persulfate, sodium persulfate and potassium persulfate are preferred initiators. Redox catalysts, which are activated in the water phase through a water-soluble reducing agent, can also be used.
• the free radical initiator is advantageously used in an amount from 0.01 to 5 percent, preferably 0.1 to 2 percent, based on the weight of the monomers. If desired, an amount of initiator or catalyst in excess of the foregoing amounts may be added after the addition of the monomer streams, in order to finish off the polymerization.
• the monomer mixture contains a monomer having free acid groups, and in particular free carboxyl groups
• a fugitive base like ammonia, dimethylamine, diethyl amine, aminopropanol, ammonium hydroxide or 2-amino- 2-methyl-1-propanol, or through the addition of an alkali such as sodium hydroxide, potassium hydroxide or sodium, potassium or ammonium carbonate.
• This base may be added toward the end of the addition of the monomer stream(s), after all the monomer addition has been completed, or after the polymerization reaction is finished.
• ingredients can also be used during the polymerization process as desired, such as chain transfer agents, buffers, or preservatives.
• the resulting emulsion may be steam-stripped or otherwise treated to remove impurities and unreacted monomers.
• the emulsion of this invention can be formulated into a variety of paints and coatings.
• the coatings can be formulated for use in a wide variety of applications, and the selection of the emulsion of this invention for use in the coating does not require any special ingredients or formulating techniques. Accordingly, those ingredients and paint and coating formulations which are well understood in the art may be used to formulate paints and coatings with the emulsion of this invention.
• the latex can be formulated in clear and pigmented coatings and paints.
• the pigmented formulation for example, will generally contain a filler, opacifying agent or pigment, such as calcium carbonate, talc, silica, aluminum hydroxide, glass powder, titanium dioxide, zinc phosphate, red oxide, carbon black, Hansa Yellow, Benzidine Yellow, Phthalocyanine Blue, or Quinacridone Red. These are generally used in amounts sufficient to provide the coating with a pigment volume concentration of 15 to 80 percent.
• the formulation may contain inorganic dispersants such as sodium hexametaphosphate or sodium tripolyphosphate, organic dispersants such as the polycarboxylic acid polymers (for example, NopcoperseTM 44c, from Summopco Co., Ltd. and OrotanTM 681 , from Rohm & Haas); wetting agents; thickeners such as polyvinyl alcohols, polyurethanes such as Acrylsol RM8, from Rohm & Haas, and cellulosic derivatives; crosslinking agents such as water soluble polyvalent metal salts, aziridine compounds, water-soluble epoxy or melamine resins, or water dispersible blocked isocyanates; surfactants; matting agents and defoamers.
• inorganic dispersants such as sodium hexametaphosphate or sodium tripolyphosphate
• organic dispersants such as the polycarboxylic acid polymers (for example, NopcoperseTM 44c, from Summopco Co.,
• Solvents such as alcohols, glycol ethers, hydroxy-tertiary amines, ketoximes, active methylene compounds and lactams may also be added.
• solvents such as alcohols, glycol ethers, hydroxy-tertiary amines, ketoximes, active methylene compounds and lactams may also be added.
• coalescing type solvents are not necessary in order to obtain good early and final blocking properties.
• a stainless steel reaction vessel is charged with 81 parts of deionized water and 0.42 part of sodium C 10 . 12 alkyl allyl sulfosuccinate and heated to 80°C. Then, 10 percent of the total charge of styrene (when used), 2-ethyl hexyl acrylate and methyl methacrylate (when used) are fed to the reactor over 20 minutes. Following the addition of the monomer stream, the contents of the reaction vessel were held at 80°C while feeding 0.12 part potassium persulfate dissolved in 5.25 parts water for 30 minutes to form seed polymer particles. Three streams were then fed to the vessel, all starting at the same time.
• the first stream contained the reminder of the styrene, 2-ethyl hexyl acrylate and methacrylic acid and methacryl oxypropyl trimethoxy silane, and was added to the reactor over 170 minutes.
• the second stream consisted of the sodium p-styrenesulfonate, the rest of the sodium alkyl(C 10 . 12 ) allyl sulfosuccinate and 28 parts of water. It was added over 180 minutes.
• the third stream contained 0.35 parts of potassium persulfate and 15.75 parts water, and was added over 190 minutes. After the streams were completed, the reaction temperature was held at 80°C for an additional 120 minutes to complete polymerization.
• the monomer compositions used are given in the following table.
• Latex Example Nos. 1-15 Multiple films were prepared from each of Latex Example Nos. 1-15.
• the films were cast on a black plastic foil commercially available from Leneta Company (Leneta foil) at a wet thickness of 150 ⁇ m.
• the resulting films were evaluated for hot-blocking resistance, water spot resistance and ethanol/water spot resistance as follows.
• each of these latexes has excellent early and final blocking resistance and good to excellent resistance to water and ethanol spotting.
• a A defoamer commercially available from Henkel
• b a nonionic tenside commercially available from Air Products
• c a wetting agent commercially available from Byk Chemie
• d a polyurethane thickener commercially available from Rohm & Haas as 30% solution
• e a matting agent commercially available from W.R. Grace & Co.
• Water/ethanol resistance was evaluated for all coatings by applying a 150 ⁇ m (wet thickness) film of the coating on samples of beech wood and drying at ambient conditions for 30 minutes, followed by application of a second 150 ⁇ m film and drying under ambient conditions. Resistance to spotting by an ethanol/water mixture was evaluated on multiple samples which were dried for two hours after application of the second film, and on other samples which were dried for 24 hours after application of the second film. The samples were evaluated by applying to each of them a filter paper soaked in a 50/50 ethanol/water mixture. The filter paper was removed from various samples after 15 minutes, 30 minutes and 2 hours. The films were then visually examined 24 hours after the filter paper was removed.
• the films are tested for water spotting resistance in the same manner, except that the filter paper is removed from various samples after 30 minutes, 1 hour and 2 hours.
• Examples 1 and 1 B were evaluated in a pigmented coating designed for architectural gloss paint applications in the following formulation:
• Orotan 681 is an anionic dispersant commercially available from Rohm & Haas; "Triton X100 is a nonionic surfactant commercially available from Union Carbide; c Acrysol RM 1020 is a polyurethane thickener commercially available from Rohm & Haas; Tiona RCL-535 is titanium dioxide commercially available from SCM Chemicals.
• the pigmented coatings were prepared by mixing the first four ingredients and grinding them together for 20 minutes, and then adding the remaining ingredients in the order listed, with slow stirring.
• the pigmented coatings were tested for blocking resistance at ambient and at elevated temperature, 20° gloss and water, ethanol and hand cream resistance according to the following test conditions:
• Identically dried films were blocked for 1 , 3 or 5 hours at 50°C/50 percent relative humidity under a load of 4 kg/25 cm 2 .
• the films were then pulled apart and the force required to pull them apart was rated on a scale of 0 to 5, with 5 meaning that no force was required to pull them apart and 0 meaning that the samples cannot be pulled apart.
• the amount of surface damage was also evaluated, and reported as a percentage of the total surface area.
• the paints were applied with a drawdown bar (150 ⁇ m wet film thickness) on glass, dried for 1 day at 23°C and 50 percent relative humidity and evaluated for 20° gloss using a Byk Glossmeter.
• the pigmented coatings were applied on glass with a drawdown bar (150 ⁇ m wet film thickness), dried for 7 days at a temperature of 23°C and 50 percent relative humidity and evaluated for water resistance by applying a drop of water on the dried film for either 5 minutes or 30 minutes.
• the film was evaluated for softening and formation of blisters 10 minutes after the water was removed, and rated on a scale of 0 to 2, with 2 meaning no film softening, 1 indicating slight film softening, 0 indicating severe film softening.
• the coatings were tested for ethanol and hand cream resistance in the same manner.
• Latex Example 16 was prepared in the same manner as Latex Examples 1 ⁇ 15, using the following monomer mixture: TABLE VIII
• Latex Example 16 had an MFFT of 15°C.
• the formulation of Latex Example No. 17 can be adjusted (Example No. 17) by substituting 5 parts by weight of methyl methacrylate for an equal amount of the 2-ethyl hexyl acrylate. In this manner, the MFFT can be further increased to 32°C.
• the MFFT can be increased to 60°C (Example 18) and by substituting yet another 5 parts by weight of methyl methacrylate for an equal amount of the 2-ethyl hexyl acrylate, the MFFT can be increased to 80°C (Example 19).
• Coatings were prepared from blends of Latex Examples 17 and 18 with Latex Example 1. The same coating formulation was used as described with respect to Examples 1-15, except that a 1 :1 (by weight) blend of c
• Example 20 was prepared by charging a stainless reaction vessel with 49 parts of deionized water, 0.17 part of sodium alkyl(C )0 _ 12 ) allyl sulfosuccinate, 0.92 part of itaconic acid and 0.09 part of sodium hydroxide (10 percent), followed by heating to 82°C. Then, a stream containing 0.12 part of sodium alkyl(C )0 . 12 ) allyl sulfosuccinate in 2.6 parts water and a second stream containing 2.3 parts styrene, 0.15 part MPTS, 2.1 parts butyl acrylate and 0.33 part 2-HEMA were added over 20 minutes.
• a second stream of 0.18 part of potassium persulfate dissolved in 7.5 parts of water was started 15 minutes after the start of the monomers and was fed to the reactor over 30 minutes, to form in situ seed particles.
• monomer streams containing 44.56 parts styrene, 38.9 parts butyl acrylate, 6.17 parts HEMA, 1.43 parts sodium alkyl(C 1(H2 ) allyl sulfosuccinate and 2.85 parts MPTS and a stream containing 0.18 part of initiator in 7.5 parts of water were added continuously to the reactor over 200 minutes.
• an additional 0.2 part of potassium persulfate in 5 parts of water were added over a 30 minute period after the end of the monomer addition.
• the reaction temperature was then held at 82°C for an additional 90 minutes to complete polymerization.
• Example 21 was prepared in essentially the same manner, except that the styrene level was decreased by 1 weight percent and the MPTS level was increased by the same amount.
• Example 22 was prepared in essentially the same manner as Example 20 except no MPTS was added to the reactor during the initial seeding step. Instead, all the MPTS was added to the reactor over 60 minutes as a separate stream after the seeding step.
• Example 20 to 22 were evaluated for hot-blocking resistance, water and ethanol spotting resistance and MFFT in the same manner as Examples 1 to 9 and 11 to 15. All are rated “+” in both water and ethanol spotting resistance, and all had an MFFT of 24°C.
• Example 20 scored a "4" on the hot-blocking resistance test, whereas Example 21 scores a "4 to 5" and Example 22 scores a "5".
• Example 23 was prepared by charging a stainless reaction vessel with 85 parts of deionized water, 2.24 parts of a polystyrene seed latex following by heating to 80°C.
• Example 23 was evaluated in a clear coat formulation of the following composition:
• the coating was evaluated for blocking by condition 1A/1 B as described above in section C1 Example 1.
• the samples for evaluating water and ethanol/water resistance were prepared by applying a 150 ⁇ m wet film onto wood and drying for 2 days at room temperature. The samples were evaluated by applying to each of them a filter paper soaked in a 50/50 ethanol/water mixture. The filter paper was removed from various samples after 30 minutes, 1 hour and 5 hours. The films were then visually inspected. The sample exposed to the filter paper for 5 hours was inspected 24 hours after the filter paper was removed.
• the films were tested for water-spotting resistance in the same manner, except that all films were inspected immediately after removal of the filter paper.
• the results of the ethanol/water spotting and water spotting tests were rated on a scale from 0 to 5, with 5 being best.
• Latex Examples 24-28 were prepared according to the procedure given for Example 1. The composition is given in Table XI.
• the resulting latexes were evaluated in essentially the same formulation as Example 23 except that only 2 parts by weight of the methylglycol:methoxybutanol mixture were used.
• the latexes were evaluated for blocking, water resistance and ethanol resistance using the same methods used for evaluating Example 23. The results are as reported in Table XII. TABLE XII

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• Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)

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Cited By (4)

Citations (9)

• 1997
  • 1997-02-14 GB GBGB9703147.0A patent/GB9703147D0/en active Pending
• 1998
  • 1998-02-05 AU AU62666/98A patent/AU6266698A/en not_active Abandoned
  • 1998-02-05 WO PCT/US1998/002111 patent/WO1998035994A1/en not_active Application Discontinuation
  • 1998-02-05 KR KR1019997007286A patent/KR20000071020A/ko not_active Application Discontinuation
  • 1998-02-05 EP EP98904902A patent/EP0960133A1/en not_active Withdrawn
  • 1998-02-05 CA CA002281529A patent/CA2281529A1/en not_active Abandoned
  • 1998-02-05 BR BR9808645-6A patent/BR9808645A/pt unknown
  • 1998-02-12 ID IDP980185A patent/ID19920A/id unknown
  • 1998-02-13 AR ARP980100659A patent/AR011674A1/es unknown

Patent Citations (10)

Non-Patent Citations (5)

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