Abstract: The present invention relates to a maleimide group-containing polymer particle containing a crosslinked polymer particle containing a group represented by the following formula (1) and to a method of producing the maleimide group-containing crosslinked polymer particle by reacting hydroxymethylmaleimide with a hydroxyl group-containing polymer particle obtained by introducing a polyethylene glycol into a crosslinked polymer particle: wherein n denotes an integer of 1 or more.

Abstract: The present invention provides a method for producing hydroxyl group-containing polymer particles including causing cross-linked polymer particles containing a (meth)acrylate polymer to react in the presence of a metal-containing ester-exchange reaction catalyst with at least one compound selected from the group consisting of a compound including at least two hydroxyl groups and a compound including at least one primary amino group and at least one hydroxyl group, the cross-linked polymer particles comprising the (meth)acrylate polymer represented by the following formula (I): wherein R1 represents a hydrogen atom or a methyl group; R2 to R4 may be the same or different from each other, and each independently represents a substituted or non-substituted alkyl group or a substituted or non-substituted aryl group, any one of which has 1 to 12 carbon atoms; and n represents an integer of 1 or more.

Abstract: An image display medium capable of displaying an image showing little change of the image density, and also little change of the image density uniformity, and being stable in density contrast, even when repeatedly rewritten over a long period, and an image formation apparatus are provided. The image display medium includes a pair of substrates disposed opposing to each other; and particle groups including at least two types of particles sealed in a space between the pair of the substrates, at least one type thereof having a positively chargeable property, and at least one of others having a negatively chargeable property, and the positively and negatively chargeable types of particles being different colors. The value of a coefficient of variation in each particle size distribution of both the positively and negatively chargeable types of particles is approximately not more than 15%.

Abstract: The present invention relates to a method of producing a functional polymer particle having at least one kind of functional group selected from the following structure group (A), which comprises the step of reacting a non-crosslinked polymer particle having a succinimidoxycarbonyl group with a compound having at least one kind of functional group selected from the following structure group (A) and at least one functional group selected from the group consisting of a primary amino group and a secondary amino group: 1

Abstract: A method of producing a non-crosslinked polymer particle having in a side chain thereof a succinimidoxycarbonyl group represented by the following structural formula (1): 1

Abstract: A crosslinked polymer particle can be obtained by carrying out a crosslinking reaction between a non-crosslinked polymer particle containing a succinimidoxycarbonyl group and a compound having two or more amino groups.

Abstract: A process for producing an acrylic polymer capable of providing a polymer controlled in molecular weight and free of colorization, and a heterogeneous polymerization catalyst used in the process for producing an acrylic polymer are provided. The heterogeneous polymerization catalyst contains (A) a radical generating substance, (B) a metallic halide containing a metallic element selected from the group consisting of the Group 4 to Group 12 elements and a halogen element selected from the group consisting of chlorine, bromine and iodine, and (C) a carrier carrying a ligand capable of forming a coordination bond with the metallic halide (B). The process for producing an acrylic polymer contains a step of polymerizing a monomer containing at least an acrylate and/or a methacrylate in the presence of the heterogeneous polymerization catalyst.

Abstract: A process for producing an acrylic polymer capable of providing a polymer controlled in molecular weight and free of colorization, and a heterogeneous polymerization catalyst used in the process for producing an acrylic polymer are provided. The heterogeneous polymerization catalyst contains (A) a radical generating substance, (B) a metallic halide containing a metallic element selected from the group consisting of the Group 4 to Group 12 elements and a halogen element selected from the group consisting of chlorine, bromine and iodine, and (C) a carrier carrying a ligand capable of forming a coordination bond with the metallic halide (B). The process for producing an acrylic polymer contains a step of polymerizing a monomer containing at least an acrylate and/or a methacrylate in the presence of the heterogeneous polymerization catalyst.

Abstract: An image display medium capable of displaying an image showing little change of the image density, and also little change of the image density uniformity, and being stable in density contrast, even when repeatedly rewritten over a long period, and an image formation apparatus are provided. The image display medium includes a pair of substrates disposed opposing to each other; and particle groups including at least two types of particles sealed in a space between the pair of the substrates, at least one type thereof having a positively chargeable property, and at least one of others having a negatively chargeable property, and the positively and negatively chargeable types of particles being different colors. The value of a coefficient of variation in each particle size distribution of both the positively and negatively chargeable types of particles is approximately not more than 15%.

Abstract: An image display medium capable of providing an image display with less change in the image density, with less change in the uniformness of the density and at stable density contrast even after repetitive rewriting over a long period of time, and an image forming apparatus using the image display medium are provided. The image display medium and image forming apparatus have a pair of facing substrates, at least two kinds of particles sealed in a space between the pair of the substrates in which the at least two kinds of particles have a characteristic that at least one kind of them is positively chargeable and at least one other kind of them is negatively chargeable, and the particles chargeable positively and negatively are of colors different from each other and a charge controller is internally added to one or both of the particles chargeable positively and negatively.

Abstract: A novel capsule toner is provided, comprising a core and a shell covering the core, wherein the shell is made of a substance capable of producing radical and there is attached to the surface of said shell a polymer comprising as monomer component a quaternary ammonium salt-containing vinyl monomer represented by formula (I): ##STR1## wherein R.sub.1 represents a hydrogen atom or methyl group; R.sub.2, R.sub.3 and R.sub.4 each represents a hydrogen atom, a C.sub.1-5 alkyl group or a benzyl group; Y represents --CO.sub.2 -- or --CONH--; n represents an integer 1 to 7; and X.sup.- represents an anion containing -COO.sup.- group, --SO.sub.3.sup.- group or --SO.sub.4.sup.- group in the structure.

Abstract: The present invention provides a process for the preparation of a microcapsule excellent in core substance retention and mechanical strength as well as in environmental protection, safety and sanitation which can be used in the form of powder in a short capsulization time at a low cost. The present invention also provides an electrophotographic microcapsule toner having an excellent environmental stability of chargeability and a process for the preparation thereof. A novel process for the preparation of a microcapsule is provided which comprises emulsifying an oily composition containing a low boiling solvent in the presence of a cellulose dispersion stabilizer, and then subjecting the emulsion to interfacial polymerization so that it is capsulized, characterized in that said capsulization is effected at a temperature of not lower than the gelation temperature of said cellulose dispersion stabilizer while said low boiling solvent being removed from the oily droplets.

Abstract: A microcapsule and a microcapsule toner each comprising a core material and an outer shell, in which the outer shell contains a vinyl polymer and a polymer comprising at least two monomers copolymerizable with each other on the surface of the core material, and a process for producing a microcapsule, which comprises the steps of: emulsifying a lipophilic core material in an aqueous medium; and causing at least two monomers copolymerizable with each other to copolymerize, in the presence of a vinyl polymer, on the surface of the oil droplets of the core material in the resulting emulsion to form an outer shell.

Abstract: A novel capsule toner obtained by dispersing an oil phase containing a binder resin and a colorant in an aqueous phase in the form of oil droplets so that one or more capsule shell-forming monomers are allowed to undergo reaction inside and/or on the interface of the oil droplets to form capsule shells is provided, wherein a silylisocyanate compound is added in the oil phase as the capsule shell-forming monomer.

Abstract: A novel process for producing a toner excellent in environmental stability of chargeability is disclosed, which comprises subjecting toner particles comprising on the surface thereof a polymer containing as monomer component a monomer having a salt structure consisting of an anionic component and a cationic component to ion exchange to replace the another anionic component with another anionic component.

Abstract: A microcapsule comprising a capsule shell having at least one polymer structure selected from the group consisting of a polyurea resin, a polyurethane resin, a polyamide resin, a polyester resin and an epoxy resin and containing a block and/or graft copolymer formed by the vinyl polymerization of vinyl monomers initiated by the decomposition of a polymerization-initiating azo group which has been previously incorporated in the polymer structure.

Abstract: A capsule toner comprising a core covered with an outer shell, the outer shell comprising a substance capable of forming a radical, a polymer comprising at least a unit derived from a quaternary ammonium salt-containing vinyl monomer represented by formula (I) being deposited on the surface of the outer shell, and basic carbon black being externally added to the capsule toner: ##STR1## wherein R.sub.1 represents a hydrogen atom or a methyl group; R.sub.2, R.sub.3, and R.sub.4 each represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a benzyl group; Y represents --COO--, --CONH-- or a phenylene group; n represents an integer of from 1 to 7; and X.sup.- represents a halogen ion or an anion having a --COO.sup.- group or an --SO.sub.3.sup.- group.

Abstract: An electrophotographic toner comprising toner particles having adhered on the surface thereof a polymer comprising a monomer unit derived from a fluorine-containing vinyl monomer represented by formula (I) or (II): ##STR1## wherein X represents --COO--, --OCO--, --O--, or a p-phenylene group; R.sub.1 and R.sub.2 each represent a hydrogen atom or an alkyl group having from 1 to 3 carbon atoms; m represents an integer of from 1 to 7; n represents an integer of from 1 to 19; o and p each represent an integer of from 0 to 7; and Y represents a hydrogen atom or a fluorine atom.The toner exhibits satisfactory charging stability against the environment or mechanical forces while having a narrow charge distribution. It can be prepared with a wide choice of materials and without requiring any special reaction apparatus.

Abstract: A toner for electrophotography having good electrification stability even under high-temperature and high-humidity conditions is disclosed, which comprises toner particles having a radical-formable substance at least on the surfaces thereof and a copolymer adherent to said surfaces, said copolymer containing as monomer units at least one vinyl group-containing carboxylic acid represented by formulae (I), (II), and (III) and a fluorine-containing vinyl monomer: ##STR1## wherein R.sub.1 represents hydrogen atom or methyl group and n is an integer of 1 to 8.

Abstract: A process for manufacturing an electrophotographic toner is disclosed, comprising preparing a toner dispersion, adding a monomer and polymerizing without an emulsifier or with an emulsifier concentration less than the critical micell concentration. The toner has triboelectrification controlling properties on its surface, not influenced by the triboelectrification properties of coloring material when used in the toner, and without adhesive coagulation of the toner particles. It has excellent triboelectrification stability against environmental change and produces a good image free of fog.