Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/04—Oxygen-containing compounds
  • C08K5/15—Heterocyclic compounds having oxygen in the ring
  • C08K5/151—Heterocyclic compounds having oxygen in the ring having one oxygen atom in the ring
  • C08K5/1545—Six-membered rings
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B40/00—Processes, in general, for influencing or modifying the properties of mortars, concrete or artificial stone compositions, e.g. their setting or hardening ability
  • C04B40/0028—Aspects relating to the mixing step of the mortar preparation
  • C04B40/0039—Premixtures of ingredients
  • C04B40/0042—Powdery mixtures
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J3/00—Processes of treating or compounding macromolecular substances
  • C08J3/12—Powdering or granulating
  • C08J3/16—Powdering or granulating by coagulating dispersions
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/36—Sulfur-, selenium-, or tellurium-containing compounds
  • C08K5/41—Compounds containing sulfur bound to oxygen
  • C08K5/42—Sulfonic acids; Derivatives thereof

Definitions

• the present invention relates to water-redispersible powders of film-forming polymers prepared from ethylenically unsaturated monomers.
• Redispersible powders are already known which are obtained by spraying - drying dispersions of acrylic film-forming polymers, in particular dispersions of polymers of vinyl esters.
• dispersions of acrylic film-forming polymers in particular dispersions of polymers of vinyl esters.
• Film-forming polymers prepared from ethylenically unsaturated monomers are frequently used as adjuvants in compositions of hydraulic mineral binders to improve their processing and properties after hardening, such as adhesion to various substrates, sealing, flexibility. , mechanical properties.
• Redispersible powders have the advantage over aqueous dispersions of being able to be premixed with cement in the form of powdery compositions ready for use usable for example for the manufacture of mortars and concretes intended to be hung on building materials. , or for the manufacture of adhesive mortars or for the production of protective and decorative plasters inside or outside buildings.
• French patent FR-A 2 245 723 relates to a freeze-dried, stable and dispersible preparation in water containing a powder of a polymer latex and a water-soluble dispersing agent which is a saccharide.
• the object of the present invention is to provide a pulverulent composition redispersible totally or almost completely in water, which is based on a film-forming polymer prepared from ethylenically unsaturated monomers, preferably by the emulsion polymerization process.
• Another object of the present invention is to provide a redispersible powder of the above type which is stable on storage without agglomeration.
• Another object of the present invention is to provide a redispersible powder of the above type which, in the form of a powder or after possible redispersion in water in the form of pseudo latex, can be used in all fields of application of latexes. make coatings (in particular paints, paper coating composition) or adhesive compositions (in particular pressure-sensitive adhesives, tile adhesives).
• Another object of the present invention is to provide a redispersible powder of the above type (or the pseudo-latex resulting therefrom) more particularly with a view to its use as additives to hydraulic binders of the mortar or concrete type and providing these binders improved adhesion after immersion in a humid environment.
• Another object of the present invention is to provide a process for the preparation of the powders of the above type from film-forming latex of polymer prepared by polymerization in aqueous emulsion.
• PVP polyvinylpyrrolodone
• the water-insoluble film-forming polymer is prepared from ethylenically unsaturated monomers, in particular of vinyl and or acrylate type.
• the water-insoluble film-forming polymers are preferably homopolymers and copolymers of vinyl acetate, styrene / butadiene, styrene / acrylate, acrylate and styrene / butadiene / acrylate.
• the film-forming polymers preferably have a glass transition temperature of between about -20 ° C and + 50 ° C, preferably between 0 ° C and 40 ° C.
• These polymers can be prepared in a manner known per se by emulsion polymerization of ethylenically unsaturated monomers using polymerization initiators and in the presence of conventional emulsifiers and or dispersants.
• the polymer emulsion content is generally between 30 and 70% by weight, more specifically between 35 and 65% by weight.
• vinyl esters and more particularly vinyl acetate alkyl acrylates and methacrylates in which the alkyl group contains from 1 to 10 carbon atoms, for example methyl, ethyl, n-butyl, 2-ethylhexyl acrylates and methacrylates; vinyl aromatic monomers, in particular styrene.
• alkyl acrylates and methacrylates in which the alkyl group contains from 1 to 10 carbon atoms, for example methyl, ethyl, n-butyl, 2-ethylhexyl acrylates and methacrylates
• vinyl aromatic monomers in particular styrene.
• ethylene and olefins such as isobutene
• vinyl aromatic monomers such as methylstyrenes, vinyltoluenes
• vinyl halides such as vinyl chloride, vinylidene chloride, diolefins especially butadiene.
• the emulsion polymerization of the monomers is carried out in the presence of an emulsifier and of a polymerization initiator.
• the monomers used can be introduced as a mixture or separately and simultaneously into the reaction medium, either before the start of the polymerization in one go, or during the polymerization by successive fractions or continuously.
• emulsifying agent use is generally made of the conventional anionic agents represented in particular by fatty acid salts, alkylsulfates, alkylsulfonates, alkylarylsulfates, alkylarylsulfonates, arylsulfates, arylsulfonates, sulfosuccinates, alkylphosphates alkali metals, salts of abietic acid, hydrogenated or not. They are used in an amount of 0.01 to 5% by weight relative to the total weight of the monomers.
• the polymerization is carried out with an anionic surfactant identical to the ionic compound c) in an appropriate amount, so as to be found in the redispersible pulverulent composition according to the invention.
• the ionic compound c) can also be added in post-polymerization and optionally combined with the surfactants of the emulsion polymerization.
• the emulsion polymerization initiator which is water-soluble, is more particularly represented by hydroperoxides such as hydrogen peroxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, paramenthane hydroperoxide, and by persulfates such as sodium persulfate, potassium persulfate, ammonium persulfate. It is used in amounts of between 0.05 and 2% by weight relative to the total of the monomers.
• hydroperoxides such as hydrogen peroxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, paramenthane hydroperoxide
• persulfates such as sodium persulfate, potassium persulfate, ammonium persulfate. It is used in amounts of between 0.05 and 2% by weight relative to the total of the monomers.
• a reducing agent such as bisulfite or sodium formaldehyde sulfoxylate, polyethyleneamines, sugars. de
• the reaction temperature is generally between 0 and 100 ° C, and preferably between 30 and 70 ° C.
• a transfer agent can be used in proportions ranging from 0 to 3% by weight relative to the monomer (s), generally chosen from mercaptans such as N-dodecylmercaptan, tertiododecylmercaptan, cyclohexene, halogenated hydrocarbons such as chloroform, bromoform, carbon tetrachloride. It makes it possible to adjust the proportion of grafted polymer and the length of the grafted molecular chains. It is added to the reaction medium either before the polymerization, or during polymerization.
• the pulverulent composition according to the invention also comprises from 0.5 to 30, preferably 5 to 20 parts by weight of at least one saccharide b) per 100 parts of film-forming polymer powder.
• This saccharide is preferably partially water-soluble and can in particular be glucose, fructose, galactose, dextrose, arabinose, sucrose, mannose and lactose.
• These sacchandes preferably have a melting point above 100 ° C and a solubility between 50 and 500 g / l.
• Lactose, galactose and mannose are the preferred sacchandes because they have a melting point above 100 ° C.
• the pulverulent composition according to the invention also comprises from 0.1 to 10, preferably from 0.5 to 5 parts by weight of at least one additive chosen from a compound alkylaromatic ionic c) or a polyvinylpyrrolidone.
• a compound alkylaromatic ionic c or a polyvinylpyrrolidone.
• the latter is preferably chosen from alkylarylsulfates, alkylarylsulfonates, lignosulfonates, of molecular mass less than 20,000, preferably 10,000.
• Sodium dodecylbenzene sulfonate is one of the preferred ionic compounds c).
• the pulverulent composition according to the invention comprises from 0.2 to 20, preferably 1 to 10 parts by weight of at least one nonionic surfactant d).
• nonionic surfactants d) which can be used during the polymerization or in post-polymerization, there may be mentioned, without implying any limitation:
• OE oxyethylene
• OP oxypropylene
• the number of OE and / or OP units is between 2 and 50.
• the ethoxylated or ethoxy-proproxylated fatty alcohols generally have from 6 to 22 carbon atoms, the OE and OP units being excluded from these numbers, and are of preferably ethoxylated.
• the ethoxylated or ethoxyproproxylated triglycerides can be triglycerides of vegetable or animal origin (such as lard, tallow, peanut oil, butter oil, cottonseed oil, oil flaxseed, olive oil, palm oil, grape seed oil, fish oil, soybean oil, castor oil, rapeseed oil, coconut oil, coconut oil), and are preferably ethoxylated.
• Ethoxylated or ethoxy-proproxylated fatty acids are fatty acid esters
• ethoxylated or ethoxy-proproxylated sorbitan esters are cyclized sorbitol esters of fatty acids from C ⁇ 0 to C 2 o such as lauric acid, stearic acid or oleic acid, and are preferably ethoxylated.
• ethoxylated triglyceride is intended to cover both the products obtained by ethoxylation of a triglyceride with ethylene oxide and those obtained by transesterification of a triglyceride with a polyethylene glycol.
• ethoxylated fatty acid includes both the products obtained by ethoxylation of a fatty acid with ethylene oxide and those obtained by esterification of a fatty acid with a polyethylene glycol.
• Ethoxylated or ethoxy-proproxylated fatty amines generally have from 10 to 22 carbon atoms, the OE and OP units being excluded from these numbers, and are preferably ethoxylated.
• Ethoxylated or ethoxy-proproxylated alkylphenols generally have 1 or 2 alkyl groups, linear or branched, having 4 to 12 carbon atoms, in particular octyl, nonyl or dodecyl.
• nonionic surfactants from the group of ethoxy or ethoxy-propoxylated alkylphenols, di (1-phenyl ethoxylates and tri (1-phenyl ethyphenols) or ethoxy-propoxylates, there may be mentioned:
• composition according to the invention may also comprise a mineral filler e) in powder with a particle size less than about 10 ⁇ m, preferably less than 3 ⁇ m.
• the composition can comprise 0.15 to 0.40 parts by weight of filler e) per 100 parts by weight of film-forming polymer powder.
• mineral filler it is recommended to use a filler chosen in particular from calcium carbonate, kaolin, barium sulphate, titanium oxide, talc, hydrated alumina, bentonite, silica and sullfoaluminate of calcium (satin white).
• This mineral filler can be added directly to the pulverulent composition or introduced during the preparation of the pulverulent composition.
• the invention also relates to the process for preparing a redispersible pulverulent composition as defined above which consists in:
• removing water from an aqueous emulsion comprising 30 to 70% of a dry extract consisting of said insoluble film-forming polymer prepared by emulsion polymerization and containing suitable amounts of the additives b), c) and optionally d) and e) - and spraying the dry residue into a powder with the desired particle size.
• aqueous emulsion comprising 30 to 70% of a dry extract consisting of said insoluble film-forming polymer prepared by emulsion polymerization and containing suitable amounts of the additives b), c) and optionally d) and e) - and spraying the dry residue into a powder with the desired particle size.
• additives can be added to the aqueous emulsion.
• aqueous emulsion of the film-forming polymer powder insoluble in water obtained by emulsion polymerization as defined above.
• This type of emulsion is commonly called latex.
• the other components of the pulverulent composition are added to this aqueous emulsion: saccharide, ionic alkylaromatic or polyvinylpyrrolidone compound, optionally the nonionic surfactant and the mineral filler.
• saccharide ionic alkylaromatic or polyvinylpyrrolidone compound
• optionally the nonionic surfactant and the mineral filler optionally the nonionic surfactant and the mineral filler.
• the respective contents of the various constituents are chosen so that the dried powder compositions have the composition defined above.
• the emulsion generally has a dry extract (film-forming polymer powder + b) + c) + d) + e)) of between 30 and 70% by weight.
• the water in this emulsion is then removed and the product obtained sprayed to obtain a powder.
• the steps for removing water from the latex emulsion and obtaining a powder can be separate or concomitant. Thus, one can use a freezing process, followed by a sublimation step, or lyophilization, drying or spray drying (drying / spraying).
• Spray drying is the preferred method because it allows the powder to be obtained directly at the desired particle size without necessarily passing through the grinding stage.
• the particle size of the powder is generally less than 500 ⁇ m, preferably less than 100 ⁇ m.
• Spray drying can be carried out in the usual manner in any known device such as for example an atomization tower associating a spraying carried out by a nozzle or a turbine with a stream of hot gas.
• the inlet temperature of the hot gas (generally air), at the top of the column, is preferably between 100 and 115 ° C and the outlet temperature is preferably between 55 and 65 ° C.
• the mineral filler e) can be added to the aqueous emulsion of starting polymer. All or part of the mineral filler can also be introduced during the spraying step in the spray drying process.
• the pulverulent compositions according to the invention are completely redispersible in water at room temperature by simple stirring.
• completely redispersible is meant a powder according to the invention which, after the addition of a suitable quantity of water, makes it possible to obtain a pseudo-latex whose particle size is substantially identical to the particle size of the latex particles present in the 'starting emulsion.
• the pulverulent compositions obtained are stable on storage; they can be easily redispersed in water in the form of pseudo-latex and used directly in the form of powder or in the form of pseudo-latex in all known fields of application of latexes. They are particularly suitable in the building industry as additives to mixtures of hydraulic mineral binders for the production of protective and decorative coatings, adhesive mortars and cement-adhesives intended for laying tiles and floor coverings. . They are particularly suitable for the preparation of ready-to-use powdered products based on cement and plaster.
• the pulverulent compositions of the invention or the pseudo-latex derived therefrom can also be used in all the other fields of application of latexes, more particularly in the field of adhesives, coating of paper and paints.
• the pulverulent compositions according to the invention may also contain the usual additives, in particular biocides, microbiostats, bacteriostats, and silicone and organic anti-foaming agents. In what follows or what precedes, the parts and percentages are expressed by weight, unless otherwise indicated.
• styrene butadiene latex dispersion containing 50% of dry extract prepared by emulsion polymerization of a weight mixture of 58% of styrene and 42% of butadiene are introduced into a 2 liter bottle.
• the aqueous dispersion has polymer particles with an average particle size of 0.12 ⁇ m.
• the previous slurry is atomized using a Buchi ® device, the inlet and outlet temperatures being 110 ° C and 70 ° C respectively.
• a latex powder with an average particle size of about 50 ⁇ m is obtained which spontaneously redisperses in water. Observation under an optical microscope reveals that we almost find the size of the starting latex, that is to say an average particle size of 0.13 ⁇ m.
• a slurry is prepared having the following composition:
• the powder keeps well (several months) if it is stored away from humidity.
• the sieving on a 5 ⁇ m mesh filter of the product redispersed and diluted 5 times indicates that less than 5% by weight of the dispersion is retained on the filter.
• the median diameter of the filtrate determined using the NICON® granulometer (light scattering) is 0.13 ⁇ m.
• the atomized product spontaneously redisperses in water at room temperature. The addition of water causes immediate disintegration of the granule in the form of small aggregates at the periphery of the grain; these disperse immediately to give the initial latex which cannot be observed under an optical microscope. No sedimentation (creaming) is observed after several days.
• Example 2 The procedure of Example 1 is exactly repeated except that the slurry has the following composition:
• a powder with a particle size of 50 ⁇ m is obtained which, redispersed in water, gives a pseudo latex with an average particle size of 0.3 ⁇ m.
• Example 2 The procedure of Example 1 is exactly repeated except that the slurry has the following composition:
• a powder with an average particle size of 50 ⁇ m is obtained which, redispersed in water, gives a pseudo latex whose average particle size is 0.15 ⁇ m.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Health & Medical Sciences (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Engineering & Computer Science (AREA)
• Ceramic Engineering (AREA)
• Dispersion Chemistry (AREA)
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• Structural Engineering (AREA)
• Adhesives Or Adhesive Processes (AREA)
• Paints Or Removers (AREA)
• Compositions Of Macromolecular Compounds (AREA)

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Citations (3)

• 1994
  • 1994-12-09 FR FR9414821A patent/FR2727976A1/fr active Granted
• 1995
  • 1995-12-06 WO PCT/FR1995/001604 patent/WO1996017891A1/fr not_active Ceased
  • 1995-12-06 AU AU43079/96A patent/AU4307996A/en not_active Abandoned

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