Abstract: The present invention describes a method to encapsulate bioactive macromolecules, as example but not limited for, peptidic drugs, into polymeric particles sizing less than 10 ?m of diameter Particle production is based on emulsification/internal gelation procedure and comprises a formation of a water-in-oil emulsion followed by solubilization of dispersed insoluble calcium complex triggering gelation of said polymer dispersed in internal phase, by ionic cross-linking with free calcium ions. Finally, resulting gelled particles dispersed in the oil phase are recovered by partition phases coupled with high speed centrifugation cycles. In this case, the present invention describes a precise methodology to recover said gelled polymeric particles after particle production and includes an addition of acetate buffer solution at predetermined pH, dehydrating agents and residual oil dissolvent agent, at predetermined concentration, followed by high speed centrifugation cycles.

Abstract: A microcapsule comprising a core containing a hydrophobic liquid or wax and a polymeric shell formed from: i) 1 to 20% by weight of polymerisable silane compound, ii) 1 to 94% by weight of hydrophobic mono functional ethylenically unsaturated monomer, iii) 5 to 98% by weight of polyfunctional ethylenically unsaturated monomer, and iv) 0 to 60% by weight of other mono functional monomer(s), wherein components (i), (ii), (iii) and (iv) total 100%, and in which the microcapsule also includes a hydrophilic polymer which is covalently bonded to the microcapsule. The invention includes a process for the manufacture of particles and the use of particles in articles, such as fabrics, and coating compositions, especially for textiles.

Abstract: Methods to produce polymeric microparticles containing nanoparticles such, as pigments, dyes and other chromophores for cosmetic use, plastic surgery therapeutic use, and tattoos have been developed. The microparticles contain within the polymer a very uniform dispersion of dye particles. The methods by which the particles are made ensure a homogeneous mixture and high loading. The microparticles are made using air, one of a number of known methods such as phase inversion, solvent evaporation, and melt processing. The improvement is in the use of a method that makes, a stable dispersion of the nanoparticles in the liquid polymer before formation of the microparticles.

Abstract: The present invention describes a process of preparing microcapsules in a UV curable water immiscible phase. The microcapsules formed according to the invention contain an aqueous phase core. The process comprises dispersing a water soluble or dispersible core material along with at least one wall forming prepolymer and a polycondensation polymerization catalyst into an aqueous solution. The aqueous phase is then dispersed into the water immiscible phase comprising UV curable monomers or oligomers forming droplets of the aqueous phase solution in the water immiscible phase. Polycondensation of the prepolymers is initiated to form polymeric wall material or microcapsules at or near the interface of the water immiscible solvent and droplets of aqueous phase solution. Following capsule formation, a UV initiator is dispersed in the water immiscible phase. The UV curable dispersion containing aqueous microcapsules can be coated on a substrate.

Abstract: Lipobeads (liposome-encapsulated hydrogels) combine properties of hydrogels and liposomes to create systems that are sensitive to environmental conditions and respond to changes in those conditions in a fast time scale. Lipobeads may be produced by polymerizing anchored or unanchored hydrogels within liposomes or by mixing anchored or unanchored hydrogels with liposomes. Giant lipobeads may be produced by shrinking unanchored nanogels in lipobeads and fusing the resulting lipobead aggregates, long-term aging of anchored or unanchored lipobeads, or mixing anchored or unanchored aggregated nanogels with liposomes. Poly(acrylamide), poly(N-isopropylacrylamide), and poly(N-isopropylacrylamide-co-1-vinylimidazole) lipobeads were produced and characterized.

Abstract: The invention discloses a population of low permeability microcapsule particles comprising an oil soluble or dispersible core material and a wall material at least partially surrounding the core material. The microcapsule wall material comprises the reaction product of a first composition in the presence of a second composition comprising an anionic emulsifier. The first composition comprises a reaction product of i) an oil soluble or dispersible amine with ii) a multifunctional acrylate or methacrylate monomer or oligomer, an oil soluble acid and an initiator. The anionic emulsifier comprises a water soluble or water dispersible acrylic acid alkyl acid copolymer, an optional initiator and an alkali or alkali salt. The reaction product of the first composition and second composition results in the formation of a low permeability microcapsule wall.

Abstract: The invention discloses a population of selected permeability microcapsule particles comprising an oil soluble or dispersible core material and a wall material at least partially surrounding the core material. The microcapsule wall material comprises the reaction product of a first composition in the presence of a second composition comprising an anionic emulsifier. The first composition comprises a reaction product of i) an oil soluble or dispersible amine with ii) a multifunctional acrylate or methacrylate monomer or oligomer, an oil soluble acid and an initiator. The anionic emulsifier comprises a water soluble or water dispersible acrylic acid alkyl acid copolymer, an optional initiator and an alkali or alkali salt. The reaction product of the first composition and second composition can result in the formation of a low permeability microcapsule wall. Optionally, one or both of the first composition initiator or water phase initiator is an energy-activated initiator, such as a UV initiator.

Abstract: A process is disclosed for preparing microcapsules having a shell thickness of at least 18 nanometers by polymerizing a tetraalkoxysilane at the oil/water interface of an emulsion containing 0.1 to 0.3 weight percent of a cationic surfactant. The microcapsules are useful to prepare encapsulated sunscreens having sufficient robustness to prevent leakage of the encapsulated sunscreen in a formulated composition.

Abstract: Particles that are encapsulated by protein are provided. Also a method for preparing protein encapsulated particles involving spraying and drying of an activated protein solution is provided. The protein encapsulated particles are particularly suited for food, feed, cosmetic and pharma applications.

Abstract: Embolic polymer particles are described.

Abstract: Microcapsules comprising one or more lipophilic substances as core material and a polymer as capsule shell, which are obtainable by free-radical polymerization of an oil-in-water emulsion comprising from 30 to 100% by weight, based on the total weight of the monomers, of one or more C1-C24-alkyl esters of acrylic and/or methacrylic acid (monomer I), from 0 to 80% by weight, based on the total weight of the monomers, of a bifunctional or polyfunctional monomer (monomers II) which is insoluble or sparingly soluble in water and from 0 to 40% by weight, based on the total weight of the monomers, of other monomers (monomers III), the lipophilic substance and solid inorganic particles having a mean particle size of from 45 to 1000 nm, and a process for producing them are described. They can be used in binding building materials, textiles and gypsum plasterboard.

Abstract: Nano-sized lipid vesicles with tailored properties are used as building blocks to generate lipid tubules between two glass surfaces. The tubules formed not only have defined orientation, width, and length, but they can also grow to be as long as 13 mm under ambient conditions, without externally supplied flow, temperature control, or catalyzing agents. The tubule membrane and its internal aqueous content can be manipulated by controlling the combination of different vesicle's lipid composition and aqueous entrapment. This self-assembly process opens up new pathways for generating complicated and flexible architectures for use in biocompatible molecular and supramolecular engineering. Aspects of the invention generate, for example, tubules encapsulated with siRNA, tubules with multiple branches, and polymerized fluorescent tubules in a single-throughput self-assembly process.

Abstract: The invention relates to a process for preparing composite particles by encapsulation of an organic-phase-depleted emulsion by polymerization, said emulsion consisting of droplets of inorganic emulsion comprising an organic phase and inorganic nanoparticles distributed in said organic phase, characterized in that the polymerization is carried out using, as the polymerization monomer, from 60% to 100% of at least one crosslinking agent and from 0% to 40% of at least one hydrophobic monomer, it being understood that at least 95% of the crosslinking agent(s) are hydrophobic. The invention further relates to the particles thus obtained, and their use in diagnostics.

Abstract: A method of producing microcapsules having an electrophoretic particle dispersion encapsulated comprises the steps of: emulsifying and dispersing a hydrophobic dispersion having electrophoretic particles dispersed in a hydrophobic medium by using a high-speed rotating stirring apparatus wherein the circumferential speed at the end of a stirring part is 2 m/s to 90 m/s, and the distance (a) between the end of the stirring part and that immobile part of the stirring apparatus which is nearest to the end of the stirring part is 0 mm<(a)<20 mm; and forming microcapsules of the emulsified and dispersed hydrophobic dispersion under stirring with a stirring blade.

Abstract: A self-healing material comprises a matrix embedded with micro-pockets of a healing-agent releasable by a crack in the matrix. The healing-agent is able to bond to the matrix to repair the crack. The healing-agent is contained in microcapsules. A corresponding catalyst for the healing-agent is embedded in the matrix and contained in a plurality of microcapsules as an emulsion. The emulsion comprises an oil, a perfluorated solvent, a hydrophobic ionic liquid, or mixtures thereof. A method of manufacturing the self-healing material comprises the steps of identifying an operational temperature range of the material, providing at least one substance as the healing-agent, which substance remaining substantially in a liquid state within the operational temperature range, identifying an operational evaporation rate of the healing-agent and providing the substance with a curing time according to the evaporation rate.

Abstract: The invention relates to a complex coacervation process based on the use of type B gelatin as polycationic colloid, for the preparation of “Halal” certified flavor-containing microcapsules.

Abstract: A process for the microencapsulation of phase transitional paraffin compounds is described. Polypropylene glycols with the average molecule weight over 400 were used as the surface tension modifiers for emulsifying the paraffin compounds. Polyisocyanates capable of being dissolved in the phase change materials were employed to promote the deposition of melamine, partially methylolated melamine and the precondensate of melamine-formaldehyde onto the hydrophobic droplets for the microencapsulation. The prepared emulsion of microencapsulated phase change materials was successfully coated on textile fabrics and the coated products showed improved thermal regulation function.

Abstract: A microcapsule produced by a method involving a primary dispersed particle and a secondary dispersed particle, the capsule formation occurring at the interface of the secondary dispersed particle. A microcapsule containing a diazonium salt represented by a specific formula. A recording material utilizing the microcapsule.

Abstract: A composition and a method for fabricating microcapsules encapsulating phase-change material by interfacial condensation polymerization are provided. In this composition and method, a surfactant and an organic solvent are not needed.

Abstract: Microcapsules possessing Lewis acid-Lewis base salt walls incorporate water-immiscible materials, such as N,N-diethyl-m-toluamide (DEET), as a core component. Such microcapsules, or similar microcapsules incorporating other core components, may be made by emulsifying a water-immiscible core component in an aqueous solution of one wall-forming reactant, such as the Lewis base, and then mixing that solution with the other wall-forming reactant, such as the Lewis acid. Various adjuvants may be included with the core component to contribute additional characteristics, such as enhancement of a controlled release characteristic or improved mechanical stability.

Abstract: A novel emulsion comprising a material which is stabilised by a polymer resin precursor having interface active molecules incorporated therein by reaction from poorly or non-surface active materials is disclosed. The process for producing such emulsions is likewise disclosed.

Abstract: A microcapsule encapsulating a disperse system is produced by preparing a liquid organic dispersion containing a resin whose acid group has been neutralized, a colored particle, and an organic solvent; dispersing the liquid organic dispersion in an aqueous medium to produce a capsule particle in the aqueous medium, the capsule particle comprising a disperse system in which the colored particle is dispersed in the organic solvent, and a wall encapsulating the disperse system; and separating the capsule particle from the aqueous medium for dryness. The liquid organic dispersion may comprise, as an organic solvent, a hydrophobic organic solvent and a polar solvent dissolving the resin constituting the wall and being miscible to the aqueous medium. The wall of the capsule particle may be crosslinked or cured with a crosslinking agent. The microcapsule is utilized for an image display device in which the colored particle is electrophoretically movable in the oil phase by a potential difference.

Abstract: Methods for forming porous insulative materials for use in forming dielectric structures of semiconductor devices are disclosed. Each insulative material may include a first, substantially nonporous state and a second, porous state. When in the first state, the insulative materials may be processed or support layers or structures which are being processed. When in the second state, the insulative materials have a reduced dielectric constant and, thus, increased electrical insulation properties. Semiconductor device structures including layers or other features formed from one of the insulative materials are also disclosed. Methods for forming the insulative material and for causing the insulative material to become porous are also disclosed.

Abstract: An encapsulation material, intended for use in encapsulated electrophoretic displays, comprises the coacervation product of a polyanionic polymer having a vinyl main chain and a plurality of anionic groups bonded to the main chain, with a cationic or zwitterionic water-soluble polymer capable of forming an immiscible second phase on contact with the polyanionic polymer.

Abstract: There are provided thermotropic liquid crystal polymer microcapsules which can show behavior of liquid crystal as it is within polymer phase due to phase separation between liquid crystal and polymer, so to be incorporated into cosmetic composition as an additive for visual effect, and in loading active ingredients within liquid crystal, can improve the stability of the active ingredients in cosmetic base; and a method for preparing the same; and cosmetic compositions containing the same.

Abstract: A series of paraffin compounds, the phase change materials (PCMs), were microencapsulated in an interfacial polymerization process to form the double-shell microcapsules with relatively low shell permeability. The inner shell is formed through the reaction between polypropylene glycols and bifunctional polyisocyanates and the outer through the reaction between bifunctional polyisocyanates and polyamines added in the continuous aqueous phase. The so prepared microencapsulated paraffin compounds emulsion can be used as the medium for temperature management in many fields.

Abstract: Microcapsules having a capsule core comprising water-soluble organic substances, and a capsule coating which is a condensate of formaldehyde resins and/or alkyl ethers thereof, a process for their preparation, their use, and compositions comprising the microcapsules.

Abstract: Microencapsulation methods and products are provided. The method includes forming, at a first temperature, a emulsion which comprises aqueous microdroplets, including the agent (e.g., a magnetic material or drug) and a cross-linkable matrix material (e.g., a protein such as albumin), dispersed in a hydrophobic continuous phase comprising an oil and an oil-soluble surfactant, the first temperature being below the temperature effective to initiate cross-linking of the matrix material, and then heating the emulsion to a temperature and for a time effective to cause the matrix material to self-crosslink, to form microparticles comprising the agent encapsulated by the crosslinked matrix material.

Abstract: Thermo-expansive microcapsules comprising a shell of a polymer produced by polymerizing a mixture of monomers, which comprises (I) a nitrile monomer, (II) a monomer having an unsaturated double bond and carboxyl groups in a molecule, (III) a monomer having two or more of polymerizable double bonds in a molecule, and optionally, (IV) a monomer different from and copolymerizable with the monomers (I), (II) and (III) and a blowing agent encapsulated in the shell. The volume retention of the expanded microcapsules of the thermo-expansive microcapsules is 50% or more after loaded with 15 MPa.

Abstract: Microcapsules comprising an agglomeration of primary microcapsules, each individual primary microcapsule having a primary shell and the agglomeration being encapsulated by an outer shell, may be prepared by providing an aqueous mixture of a loading substance and a shell material, adjusting pH, temperature, concentration and/or mixing speed to form primary shells of shell material around the loading substance and cooling the aqueous mixture until the primary shells agglomerate and an outer shell of shell material forms around the agglomeration. Such microcapsules are useful for storing a substance and for delivering the substance to a desired environment.

Abstract: Described herein are microcapsules and emulsions prepared from low Bloom gelatin and methods of making and using thereof.

Abstract: A dye, such as a fluorescent dye, is incorporated into polymer microparticles using a solvent system composed of a first solvent in which the dye and the microparticle polymer are soluble, a second solvent in which the dye and the microparticle polymer are not or only weakly soluble, and a third solvent in which the dye and the microparticle polymer are not or only weakly soluble. The first and second solvents are immiscible with each other, or at most partially miscible. The third solvent is miscible with the first and second solvents. The formulation provides substantially complete partitioning of the dye to the microparticles. The method may be used to obtain dyed polymer microparticle formed of cross-linked or non-cross-linked polymers. Libraries are provided comprising two or more sets of microparticles of different dye loadings.

Abstract: A process for disposing of solvent-containing liquids so that they do not contaminate ground water. An absorbent blend is mixed into a water-containing solvent mixture at the rate of about 1 lb. of blend per gallon of liquid. The blend is made up of a swellable polymer, consisting of polyacrylamide/polyacrylate co-polymer salt or poly 2-propenamide-co-2-propenoic acid homopolymer salt which swells and absorbs liquid. The blend also contains a mixture of solid absorbents. The resulting mixture is stirred in the container until it becomes thick and then it is allowed to set to provide a disposable modeling clay-like solid. The resulting solid material, after curing, may be then simply added to solid trash, and thus, be freed from contaminating ground water.

Abstract: An oil phase solution injected into a mixing flow path from an upstream injection inlet forms a flow from an upstream injection inlet to a discharge outlet, and a rotary blade is provided downstream of a mechanical seal. Thus, a reverse flow toward a mechanical seal of a polyvalent isocyanate and a polyol injected from an inlet downstream with respect to the mechanical seal tends not to take place. A separating film member is provided to prevent the chemical solutions flowing in the mixing flow path from coming into contact with a pressing means, which is for pressing a seal ring member of the mechanical seal against a rotation ring member. A reaction product is not adhered to the pressing means of the mechanical seal, which would decrease the pressing force, and leakage of the liquid from the mechanical seal can be effectively prevented.

Abstract: The present invention provides novel encapsulation compositions and methods. In particular, the invention relates to fluorescent capsule compositions, which consists of a layer of a polymer shell enclosing one or more fluorescent materials such as fluorescent microspheres and which are capable of emitting at least two distinct fluorescent signals. Also provided are methods for their preparation. The compositions and methods of this invention are useful in a variety of applications, including preparation of multiplexed arrays for industrial, chemical, immunological, and genetic manipulation and analysis especially as related but not limited to flow cytometry.

Abstract: The present invention relates to microcapsule dispersions comprising microcapsules having a capsule core comprising water-soluble organic substances, and a capsule coating which essentially consists of polyurethane and/or polyurea, in a hydrophobic solvent which consists of 50 to 100% by weight of glycerol ester oils and 0 to 50% by weight of solvents miscible with glycerol ester oils, and to a process for their preparation.

Abstract: A microcapsule which includes a polymer as a capsule wall of the microcapsule, in which the polymer is obtained by polymerizing a dendritic branching molecule having a hydroxyl group in a terminal thereof, an isocyanate compound, and a compound having two or more active hydrogen atoms in a molecule thereof. A process for manufacturing a microcapsule includes the step of polymerizing an isocyanate compound, a dendritic branching molecule having a hydroxyl group in a terminal thereof, and a compound having two or more active hydrogen atoms in a molecule thereof, so as to form a capsule wall of the microcapsule.

Abstract: A novel method of encapsulating an active substance in a biodegradable polymer, which comprises: a) dissolving said biodegradable polymer in an organic solvent therefor; b1) dispersing said active substance in the organic solution obtained in step a) to provide a dispersion with the active substance as the inner phase thereof; or alternatively b2) emulsifying said active substance, dissolved in water or other aqueous solvent therefor, in the organic solution obtained in step a) to provide an emulsion with the active substance as the inner aqueous phase thereof; and c) subjecting the dispersion obtained in step b1), or alternatively the emulsion obtained in step b2), to an encapsulation operation with an aqueous polyethylene glycol solution as a continuous phase to provide micro- or nanoparticles having the active substance encapsulated therein. Sustained release particles obtainable thereby.

Abstract: This invention relates to micro-encapsulated particles of solid matter and a quasi-continuous method for producing the same, especially those having water-insoluble characteristics or a hydrophobic form, taking into careful consideration ecologically and economically favorable ways of recycling the media used, and the resulting smallest possible amount of waste products such as waste water and polymer residues, while simultaneously ensuring that even exposed parts of the solid bodies are coated, such as crystal tips and grooves, which are insufficiently coated using standard methods due to the hydrodynamic conditions on these areas.

Abstract: The present invention relates to a process for preparing silica microcapsules and more particularly, to a process for preparing silica microcapsules comprising the steps of dissolving tetraethyl orthosilicate (TEOS) into an aqueous solution containing a hydrolysis catalyst to control a degree of hydrolysis and contribute hydrophilicity or lipophilicity, adding a core material and an appropriate amount of aminopropyltrialkoxysilane(APS) as a gelling agent into the solution, and emulsifying and dispersing the resulting solution to a solution having a polarity opposite to that of the core material to microcapsulate by coating the core material with silica shell via a sol-gel reaction. The process for preparing microcapsules of the present invention reduces environmental pollution compared to conventional processes using an alkali gelling agent such as an ammonia solution, and are suitable for both organic or inorganic core materials having hydrophilic or lipophilic property.

Abstract: The present invention relates to microspheres, processes for the manufacture of said microspheres, pharmaceutical compositions comprising said microspheres, and sustained release methods of administering an effective pharmaceutical amount of a bioactive compound to a subject. The microspheres of the present invention comprise a water insoluble organic matrix comprising an interior region, throughout which are homogeneously dispersed a plurality of microcapsules consisting essentially of a core of bioactive compound coated with material containing charged organic groups and a surface region substantially free of said bioactive compound.

Abstract: A microcapsule in which a capsule wall of the microcapsule comprises a first polymer component. A surface of the capsule wall is modified with a second polymer component that is formed from a monomer having an ethylenic unsaturated bond.

Abstract: An improved process for the preparation of microcapsules consist sentially of a wall material and a core material in condensing a melamine-formaldehyde precondensate and/or methyl ethers thereof in an aqueous dispersion of a water-insoluble core material and in the presence of an acrylic acid/acrylamide copolymer at acidic pH and at a temperature in the range of from 20° to 100° C., and hardening thereafter the melamine-formaldehyde precondensate to form the walls of the microcapsules at an elevated temperature, wherein the core material is dispersed in the precondensate/copolymer solution without initial partial condensation of the precondensate and copolymer and wherein the hydrophobe point of the precondensate and/or its methyl esters is less than 90° C., as well as microcapsules, paper and pressure-sensitive recording material comprising such microcapsules.

Abstract: A process for encapsulation of polar organic solvents with amphiphilic copolymer shell using controlled/living polymerization is provided for the first time. To encapsulate polar core-oils an amphiphilic polymer is required that has low interfacial tensions with both the oil phase and the water phase. For example, Poly(methyl methacrylate-co-poly(ethylene glycol) methacrylate) (PMMA-co-PegMA) was prepared in suspension polymerization conditions using atom transfer radical polymerization (ATRP). ATRP ensures that the water soluble comonomer, PegMA, is incorporated into every polymer chain throughout the polymerization reaction so that all chains possess the desired amphiphilic character. Crosslinking of PMMA-co-PegMA with diethylene glycol dimethacrylate (DegDMA) yielded hollow capsular particles at 31 mol % PegMA in the terpolymer.

Abstract: The present invention relates to microcapsule dispersions comprising microcapsules having a capsule core comprising water-soluble organic substances, and a capsule coating which essentially consists of polyurethane and/or polyurea, in a hydrophobic solvent which consists of 50 to 100% by weight of glycerol ester oils and 0 to 50% by weight of solvents miscible with glycerol ester oils, and to a process for their preparation.

Abstract: A method of making a multichromal sphere includes the steps of preparing a composition of at least (1) a matrix material and (2) at least two sets of particles, each of the sets of particles having a color different from at least one of another of the sets of particles and a segregation (e.g., an electrical or magnetic) property different from at least one of another of the sets of particles, encapsulating the composition within a shell to form an encapsulated sphere, immobilizing the encapsulated sphere in a manner to restrict at least rotation of the encapsulated sphere, subjecting the immobilized encapsulated sphere to an external field associated with the segregation property different among the sets of particles, under conditions in which the sets of particles are able to migrate within the matrix material, thereby producing color segregation in the immobilized encapsulated sphere, and solidifying the matrix material while substantially maintaining the color segregation.

Abstract: A method is described for the formation of microcapsules which contain a liquid composition in the core, which is surrounded by a polymeric shell, membrane, or coating. The microcapsules are produced by simultaneously extruding the liquid core material along with a polymerizable liquid through concentrically-aligned nozzles to form spherically-layered biliquid droplets, followed by energy input in the form of heat or light which causes polymerization of the outer layer. The capsules formed by this method are capable of containing a variety of liquid materials having a composition ranging from completely aqueous to completely non-aqueous.

Abstract: Inorganic-organic hybrid mixture sol-gel encapsulated lipid vesicles which are composed of silyl lipids or a mixture of silyl lipids and phospholipids are provided. The present invention also provides encapsulated Langmuir Blogget (LB) membranes and biological macromolecules. The sol-gel encapsulated lipid vesicles, LB membranes and proteins possess a higher stability than conventional vesicles. Inorganic-organic hybrid mixture sol-gels are provided as novel sol-gel materials possessing desirable mechanical and physicochemical properties. Also provided are methods of preparing encapsulated lipid vesicles, LB membranes and proteins. Methods of performing renal dialysis using compositions of the invention are also provided.

Abstract: The invention relates to micro-capsules comprising a capsule core containing water-soluble, organic substances and a capsule shell, which is a condensate of formaldehyde resins and/or their alkyl ethers. The invention also relates to a method for producing said micro-capsules, to the use thereof and to agents containing the micro-capsules.

Abstract: Described is a process for preparing a dispersion of microcapsules by condensing a partially methylated melamine-formaldehyde resin having a molar ratio of melamine:formaldehyde:methanol of from 1:3.0:2.0 to 1:6.0:4.0 in water in which the essentially water-insoluble material forming the capsule core is present in dispersion in the presence of an alkali metal salt of a homopolymer or copolymer of 2-acrylamido-2-methylpropanesulfonic acid as protective colloid at a pH of from 3 to 6.5 by preforming the microcapsules at a temperature of from 20 to 50° C. and then curing the capsule wall of the preformed microcapsules at >50 to 100° C., which comprises adding from 5 to 100% by weight of melamine, based on the melamine-formaldehyde resin, in the course of curing. The microcapsule dispersions are formaldehyde-reduced and of low viscosity.