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
  • C08F2/04—Polymerisation in solution
  • C08F2/10—Aqueous solvent

Definitions

• the present invention relates to water-in-water emulsions, and in particular to aqueous dispersions based on water-soluble polymers intended for use as a thickener in aqueous systems.
• Water-in-water emulsions can be used as a thickener for aqueous systems used in particular in textile and paint applications.
• Viscosifying water-soluble polymers are used for various applications and in particular in the field of paints, glues and adhesives, construction, textiles and paper.
• the aqueous and / or pigmented compositions often dealt with by a person skilled in the art, for example aqueous paints, consist of a liquid phase which can be water or a mixture of water with a miscible organic solvent with water, a polymer dispersed in the liquid phase, commonly called “binder", fillers and / or pigments, a dispersing agent for fillers and / or pigments, which can be a water-soluble polymer, as well as the various adjuvants such as coalescing agents, biocides, defoamers or others, finally one or more viscosifying agents (or thickeners) which are natural or synthetic polymers.
• polymers increase the viscosity of the solutions in which they are dissolved.
• the water-soluble polymers generally used as viscosifiers of aqueous solutions have various structures; by way of indication, mention may be made of polyacrylamides, optionally partially hydrolyzed, sodium poly (meth) acrylates, cellulose derivatives, poly (ethylene oxide) or also polysaccharides. It is well known that the aqueous systems of such water-soluble polymers with a high solids content are gelatinous and have very high viscosities, which make their handling and storage difficult. The problem posed to a person skilled in the art is the production of such aqueous systems but having both a high dry extract and a low viscosity.
• a new polymerization technique has been developed leading to aqueous dispersions of water-soluble polymers whose originality lies in terms of presentation, that is to say free of polluting solvent, not generating of dust, quickly soluble in water, of low viscosity even at high polymer content, and ready for use.
• this technology requires the development of a polymer dispersant suitable for the stability of the dispersed polymer in a saline or non-saline medium.
• Such a dispersant must be chosen and used under conditions which make it possible to generate the incompatibility with the polymer formed during synthesis in order to induce the formation of a dispersed phase. It can also generate specific interactions with the polymer in order to make it insoluble in an aqueous medium and generate particles.
• EP 1 70 394 describes a dispersion of a polymer gel particle of size greater than 20 ⁇ m in a solution of dispersant of poly (sodium acrylate) or of poly (DADMAC), designating polydiallyldimethylammonium chloride.
• this product has the disadvantage of having insufficient stability and a high viscosity after a long period of storage. The viscosity can only be reduced after shearing or stirring.
• US Patent 5403883 describes a technique for obtaining dispersions of cationic polymers without salt, and of low viscosity by polymerization in the presence of the dispersant poly-DADMAC, of a mixture of at least one water-soluble monomer, at least one hydrophobic monomer and if necessary an amphiphilic monomer.
• Post-addition of the same poly-DADMAC dispersant makes it possible to reduce the viscosity (CA 31 23460). However, it has the effect of increasing the level of dispersant and leading to a dispersion having a low level of dispersed polymer.
• the problem that the invention seeks to solve is therefore the preparation of aqueous dispersions of water-soluble polymers which are stable on storage and do not contain an organic solvent.
• the Applicant has now developed new water-in-water emulsions which do not have the drawbacks of the dispersions mentioned above. Because on the one hand, they have particles with an average diameter of less than 3 ⁇ m. This guarantees the absence of sedimentation and therefore good stability during storage. On the other hand, such particles can be obtained without incorporating a complexing dispersant. In fact, thanks to the use of specific monomers, it is possible to induce the formation of inter and intrapolymer complexes. However, the introduction of dispersant in small quantities is recommended in order to increase the fluidity of the emulsion. The Applicant has found that the incorporation into the mixture of water-soluble monomers to be polymerized of a monomer having a radical (R) containing both a block 4
• polyethoxylated and a hydrophobic block and of a monomer which can form specific interactions with the polyethoxylated block, allows intra and interpolymer complexation and the formation of particles of small diameter.
• the dispersions of the invention keep their particles in the state at the time of dilution with water even under the conditions of high dilution.
• the dispersed polymer becomes water-soluble, generating an increase in viscosity, under the basic conditions of paint application or pigment printing.
• the first object of the invention is an aqueous dispersion containing:
• a complexing dispersant capable of forming complexes with the water-soluble polymer by interpolymer interactions such as hydrogen bonds or polar interactions.
• the polymers of the invention consist essentially of water-soluble monomers. They contain units derived by polymerization of at least one neutral or anionic monomer (A), at least one monomer (B) having a polyethoxylated radical ending in a hydrophobic group and at least one monomer (C) capable of complex with the monomer (B) by polar interactions or by hydrogen bonds.
• A neutral or anionic monomer
• B monomer having a polyethoxylated radical ending in a hydrophobic group
• C monomer capable of complex with the monomer (B) by polar interactions or by hydrogen bonds.
• They can also contain units derived from at least one polyunsaturated monomer (D) and this in order to have crosslinked polymer particles.
• the polymers of the invention contain:
• Another object of the invention is the process for the synthesis of water-in-water emulsions containing water-soluble polymers dispersed in the form of particles with a diameter of less than 3 ⁇ m.
• the dispersions of the invention are prepared by radical polymerization of an aqueous solution containing: from 0 to 98.98 mol% of at least one monomer A from 0.02 to 5 mol% of at least one monomer B from 1 to 99.98% by mole of at least one monomer C from 0 to 2% by mole of at least one monomer D in the presence of 0 to 15% by weight relative to the total weight of the monomers of at least a complexing dispersant.
• the monomers A are chosen from the group consisting of acrylamide, methacrylamide, N-alkylacrylamide, N, N di-alkylacrylamide, N-vinyl methacetamide, N-vinyl methylformamide, N-vinyl pyrolidone, ( meth) acrylates comprising a polyethoxylated side chain terminated by a hydrogen or a CH3 and their mixtures.
• the preferred monomer A is acrylamide.
• the monomers B are chosen from the group corresponding to the following formula:
• R- is hydrogen or methyl n is an integer between 2 and 50
• R 2 is either a C2-C40 alkyl radical, or a C5-C40 aryl radical, or a C7-C40 alkylaryl radical, or a C5-C40 cycloalkyl, or an alkylene and propylene or higher homolog.
• the preferred monomer B of the invention is polyethoxylated tristyryl phenol methacrylate corresponding to the formula
• the monomers C are vinyl or acrylic monomers comprising functional groups chosen from acid groups (carboxylic, sulfonic, phosphoric, sulfuric) and their salts, sulfuric ester, sulfone, hydroxyl, amino, imino, tertiary amino, quaternary ammonium, pyrolidone , and hydrazino.
• the preferred monomer C of the invention is acrylic acid.
• the monomer D is chosen from the group consisting of N, N methylene-bis acrylamide, a di-acrylate such as ethylene glycol di-acrylate, or polyethylene glycol di-acrylate, a di-allyl compound such as diallylacetic acid or diallyl phthalate, an ethylene glycol allyl acrylate or a polyethylene glycol allyl acrylate.
• the preferred monomer D of the invention is N, N methylene-bis acrylamide.
• the complexing dispersant according to the invention is generally a water-soluble polymer of average mass by weight of 300 to 500,000 and preferably comprising one or more functional groups chosen from ether, hydroxyl, carboxyl, sulfone, sulfuric ester, amino, imino, amino tertiary, quaternary ammonium, and hydrazino, among which particular preference is given to the ether, hydroxyl, and carboxyl groups.
• Typical examples of these dispersants are poly (ethylene oxide), polyvinyl alcohol, and poly (N vinyl pyrolidone).
• the polymerization is carried out as follows:
• the mixture of monomers represents from 10 to 40% and preferably 15 to 30% by weight of the reaction mixture consisting of water, of dispersant, and of monomers, the dispersant representing from 0 to 6% and preferably from 0.5 to 3% by weight.
• the polymerization can be initiated by various means, such as free radical generators such as peroxides, diazo compounds or persulfates, or by irradiation.
• the preferred mode according to the invention is the initiation with potassium, sodium or ammonium persulfate. These initiators can be combined with a decomposition accelerator.
• the polymerization temperature is between 0 and 100 ° C and preferably 40 and 95 ° C. The conversion is greater than 99%.
• the water-in-water emulsions obtained can be used to thicken aqueous systems such as latex in an alkaline medium, for paint and textile applications, in particular pigment printing.
• Example 1 illustrates the invention without limiting it. In all the examples below, the parts are given by weight.
• Example 1 illustrates the invention without limiting it. In all the examples below, the parts are given by weight.
• Ot7 obtains a stable dispersion of Brooklield 19,000 cp viscose polymer at 25 ° C and an average particle diameter determined by light scattering of 0.725 ⁇ m.
• Comparison of Examples 1 and 2 shows that the presence of the special polyethoxylated tristyryl phenol methacrylate monomer is necessary to form water-in-water emulsion particles.
• Example 2 The same synthesis is repeated as in Example 1, but removing the polyethylene oxide dispersant. A stable dispersion of polymer with a Brookfie viscosity / d 47,000 cp at 25 ° C. and an average particle diameter determined by light scattering of 1.13 ⁇ m is obtained.
• Example 2 The same synthesis is repeated as in Example 1 but incorporating 500 ppm by weight of N N methylene bisacrylamide relative to all of the monomers. A stable dispersion of polymer with Brookfield viscosity 48,000 cp at 25 ° C. and an average particle diameter determined by light scattering of 1 ⁇ m is obtained.

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• Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Polymerisation Methods In General (AREA)
• Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
• Paints Or Removers (AREA)
• Emulsifying, Dispersing, Foam-Producing Or Wetting Agents (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Macromonomer-Based Addition Polymer (AREA)

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• 1998
  • 1998-04-01 FR FR9804033A patent/FR2777011B1/fr not_active Expired - Fee Related
• 1999
  • 1999-03-22 AU AU28447/99A patent/AU2844799A/en not_active Abandoned
  • 1999-03-22 CN CN99800846A patent/CN1272117A/zh active Pending
  • 1999-03-22 EP EP99909066A patent/EP0986583A1/de not_active Withdrawn
  • 1999-03-22 CA CA002292743A patent/CA2292743A1/fr not_active Abandoned
  • 1999-03-22 JP JP54894899A patent/JP2002500699A/ja active Pending
  • 1999-03-22 WO PCT/FR1999/000663 patent/WO1999050308A1/fr not_active Application Discontinuation

Non-Patent Citations (1)

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