Colloid systems and wetting agents; subcombinations thereof; pro – Continuous liquid or supercritical phase: colloid systems;... – Primarily organic continuous liquid phase
Reexamination Certificate
2000-03-20
2002-06-25
Lovering, Richard D. (Department: 1712)
Colloid systems and wetting agents; subcombinations thereof; pro
Continuous liquid or supercritical phase: colloid systems;...
Primarily organic continuous liquid phase
C424S401000, C427S213340, C516S076000, C516S928000, C523S210000, C524S801000, C526S911000
Reexamination Certificate
active
06410605
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process for preparing an emulsion. More specifically, the present invention relates to a solid particles-containing emulsion which can be suitably used in paints, inks for ink jet printers, fiber-treated agents, coating-materials, adhesives, skin cosmetics, hair cosmetics, and the like.
2. Discussion of the Related Art
As a process for preparing an oil-in-water emulsion in which solid substances useful for liquid droplets are contained, there has been known a process comprising previously adding lipophilic solid particles to be contained to an oil, and thereafter emulsifying and dispersing the resulting mixture (Japanese Patent Laid-Open No. Sho 62-234541). However, in this process, since the viscosity becomes high when the content of the solid substances becomes high, there arise defects that the dispersion of the solid substance is likely to be difficult, and even when the solid substance is emulsified in a solvent incompatible with a solid-liquid mixture, its dispersion is likely to be difficult, so that the ratio of the solid substance cannot be increased.
In addition, when an emulsion prepared by emulsifying and dispersing oil droplets as polymerizable monomers is subjected to suspension polymerization, it is necessary to dissolve a polymerization initiator in a dispersed phase. However, a long period of time is required for dissolving the polymerization initiator in the solid-liquid mixture, and it is difficult to confirm that the polymerization initiator is dissolved. Therefore, there arises a defect that the dispersion of the solid substance is insufficient, because not so much time can be spent for the dispersion of the solid substance in the solution prepared by dissolving the polymerization initiator from the aspect of stability of the polymerization initiator.
An object of the present invention is to provide a process for preparing an emulsion which allows to include solid particles in oil droplets or water droplets (hereinafter simply referred to as “dispersion droplets”); and a process for preparing a solid particles-containing polymer emulsion comprising including a polymerizable monomer in the dispersion droplets of the emulsion, and polymerizing the polymerizable monomer.
Another object of the present invention is to provide a process for preparing an emulsion which allows to include solid particles in the dispersion droplets, wherein the dispersion droplets have a small average particle diameter and are substantially free from agglomerates.
SUMMARY OF THE INVENTION
According to the present invention, there are provided:
[1] a process for preparing a solid particles-containing emulsion comprising mixing an oil droplets-in-water emulsion with lipophilic solid particles or a dispersion thereof, thereby allowing to include the lipophilic solid particles in the oil droplets;
[2] a process for preparing a solid particles-containing emulsion comprising mixing a water droplets-in-oil emulsion with hydrophilic solid particles or a dispersion thereof, thereby allowing to include the hydrophilic solid particles in the water droplets; and
[3] a process for preparing a solid particles-containing polymer emulsion comprising including a polymerizable monomer in the water droplets, preparing solid particles-containing emulsion by the process according to item [1] or [2], and polymerizing the polymerizable monomer.
DETAILED DESCRIPTION OF THE INVENTION
The term “contain” as referred in the present invention encompasses not only the state in which the solid particles are incorporated in the dispersion droplets, but also the state in which a part of the solid particles is contained in the dispersion droplets or the state in which the solid particles are deposited on the surface of the dispersion droplets. In addition, the technical idea of the term “contain” also encompasses the state in which the dispersion droplets are polymer droplets, and the solid particles are deposited to the surface of polymer particles. The solid particles to be contained may be either an inorganic compound or an organic compound.
The term “lipophilic solid particles” as referred in the present specification means particles having a surface which forms a contact angle when brought into contact with water. The lipophilic solid particles include those having both lipophilic surface and hydrophilic surface and those in which a hydrophilic surface is surface-treated to give a hydrophilic surface having a lipophilic surface.
The lipophilic solid particles include organic pigments such as monoazo, dis-azo, benzimidazolone, quinacridone, phthalocyanine and other organic pigments; and inorganic pigments such as carbon black. It is desired that the lipophilic solid particles have an average particle diameter of preferably 0.05 to 10 &mgr;m, more preferably 0.05 to 5 &mgr;m, still more preferably 0.05 to 1 &mgr;m, from the viewpoint of the stability of the emulsion.
The term “hydrophilic solid particles” as referred in the present specification means particles having a surface which does not form a contact angle when brought into contact with water. The hydrophilic solid particles include those having both hydrophilic surface and lipophilic surface and those in which a lipophilic surface is surface-treated to give a lipophilic surface having a hydrophilic surface.
The hydrophilic solid particles include titanium oxide, silica, zeolite, barium sulfate, calcium carbonate, kaolin, iron oxides, and the like. It is desired that the hydrophilic solid particles have an average particle diameter of preferably 0.05 to 10 &mgr;m, more preferably 0.05 to 5 &mgr;m, still more preferably 0.05 to 1 &mgr;m, from the viewpoint of the stability of the emulsion.
When the solid particles are used in a form of dispersion, a dispersing agent for dispersing the solid particles is used as occasion demands.
The dispersing agent includes anionic surfactants such as dodecylsulfates, dodecylbenzenesulfonates, and sulfates of polyoxyethylene nonyl phenyl ethers; nonionic surfactants such as polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene-polyoxypropylene block copolymers, and sucrose ester of fatty acids; cationic surfactants such as octadecyltrimethylammonium chloride; amphoteric surfactants such as alkyl dimethylaminoacetate betaines and 2-alkyl-N-carboxy-N-hydroxyimidazolium betaines; natural or synthetic high-molecular compounds such as polyvinyl alcohols, gelatin, polyvinyl pyrrolidones, polymethyl vinyl ethers, polybutadienes, proteins, hydroxyalkyl celluloses, polyurethane resins, and acrylic resins, and the like.
The component in the oil phase and the component in the water phase used during the preparation of an O/W or W/O emulsion are selected so that these components are incompatible with each other.
The component in the oil phase incompatible with water is preferably an organic compound having a solubility to water of not more than 1 g per 100 g of water at 20° C. The organic compound includes cyclohexane, n-hexane, benzene, cottonseed oil, rapeseed oil, squalane, squalene, waxes, styrene, divinylbenzene, butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, decyl acrylate, lauryl acrylate, dodecenyl acrylate, myristyl acrylate, palmityl acrylate, hexadecenyl acrylate, stearyl acrylate, octadecenyl acrylate, behenyl acrylate, butyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate, decyl methacrylate, lauryl methacrylate, dodecenyl methacrylate, myristyl methacrylate, palmityl methacrylate, hexadecenyl methacrylate, stearyl methacrylate, octadecenyl methacrylate, behenyl methacrylate, silicone macromonomers, and the like.
The component in the water phase incompatible with the component in the oil phase includes water alone, and water solutions prepared by dissolving optional necessary ingredients in water.
When an emulsion is prepared, there can be used a dispersing agent such as the surfactants and the natural and/or synthetic high-mo
Funada Kouichi
Kubo Hideaki
Nakamura Hidetake
Shimada Toshiya
Kao Corporation
Lovering Richard D.
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