Abstract: A process for producing a solvent-free acrylic sheet includes a coating step which may involve either coating at least one support with a solvent-free syrupy composition for coating polymerization or applying the solvent-free coating polymerization syrupy composition between at least two supports at a coating thickness of at least 0.15 mm to form a laminate. The solvent-free coating polymerization syrupy composition includes an acrylic vinyl monomer capable of radical polymerization.The process further includes a heating polymerization step in which the laminate is heated at 60.degree. C. or higher for reaction initiation so that autoexotherm is induced to cause the acrylic vinyl monomer to polymerize.The process concludes with an aging polymerization step in which the laminate having undergone the heating polymerization step is maintained at a temperature that is at least 30.degree. C.

Abstract: The acrylic sheet of the invention is an acrylic sheet containing particles homogeneously dispersed in a resin matrix which does not substantially contain air bubbles and has an air bubble content of not more than 10% by volume; in which the resin matrix for constituting the acrylic sheet is a crosslinked (meth)acrylic copolymer obtained by forming a crosslinked structure among the molecules of a (meth)acrylic copolymer, which is a copolymer of 0.1-15% by weight of a polymerizable monomer having a functional group, 60-99.9% by weight of a (meth)acrylic acid alkyl ester and 0-39.9% by weight of other monomer and has a weight-average molecular weight of 150,000 to 1,200,000, by means of a polyfunctional compound having reactivity to the functional group of the polymerizable monomer for preparing the (meth)acrylic copolymer; and the particles dispersed in the resin matrix formed from the crosslinked (meth)acrylic copolymer have a mean particle diameter of 1 to 100 .mu.m and a true specific gravity of 0.2 to 3.0.

Abstract: A process for producing a hydrophilic group-containing macromonomer having an ethylenically unsaturated group at the end thereof comprising reacting a hydrophilic group-containing polymer having a carboxyl group at the end thereof, with an ethylenically unsaturated group-containing epoxy compound in the presence of a hydrophilic organic solvent. According to the process of the present invention, there is provided a process for producing a hydrophilic group-containing macromonomer having an ethylenically unsaturated group at the end thereof which has been not known in the prior art.

Abstract: A graft copolymer having dispersion stabilizing effect, which comprises on the carbon backbone thereof a polymer side chain comprising a carbon chain having a molecular weight of 1,000.about.100,000, a fluorine atom containing fluorine side chain and a hydrophilic side chain containing a hydrophilic group, the total mean molecular weight of said graft copolymer being 5,000 or more. The graft copolymer of this invention can be used as an excellent dispersion stabilizer for emulsion polymerization, whereby in emulsion polymerization it is possible to attain polymer particle dispersion stability to ensure that the polymer particles will not be agglomerated even if they have been grown to larger particles having a diameter of 0.5.mu. or more and that dispersion of the polymer particles having a large and uniform particle diameter is obtained.

Abstract: A process for producing a hydrophilic group-containing macromonomer having an ethylenically unsaturated group at the end thereof comprising reacting a hydrophilic group-containing polymer having a carboxyl group at the end thereof, with an ethylenically unsaturated group-containing epoxy compound in the presence of a hydrophilic organic solvent. According to the process of the present invention, there is provided a process for producing a hydrophilic group-containing macromonomer having an ethylenically unsaturated group at the end thereof which has been not known in the prior art.

Abstract: A graft copolymer having dispersion stabilizing effect, which is a product of the polymerization of 5 to 30% by weight of a macromonomer which has a molecular weight of 1,000 to 100,000 and has a radical polymerizable unsaturated group at its one end, 1 to 40% by weight of a hydrophillic monomer which has a hydrophillic moiety in it and has a radical polymerizable unsaturated group, and 5 to 40% by weight of a fluorinated monomer which has a florinated moiety in it and has a radical polymerizable unsaturated group, the % by weight being based on a total of the three monomers, and 0 to 50% of the total of the total of the three monomers of a monomer copolymerizable therewith.

Abstract: The present invention relates to an impregnated cathode produced by attaching at least two layered thin films, the thin films comprising an under layer consisting of a high melting point metal thin film composed of, for example, Os, Ru, Rh, Pd, Ir, Pt, Re, Mo, W, Ta, etc., and an over layer consisting of a high melting point metal layer which contains Sc.sub.2 O.sub.3 and which is placed over the layer, on the surface of the impregnated cathode pellet generated by impregnating a refractory porous base body with electron emissive materials. The invention relates also to an electron tube having this cathode. This cathode maintains a low work functional mono-layer stably for a long period of time on its surface.

Abstract: A field emission cathode of the present invention is characterized by the possession of a special layer which is adsorbed onto the surfaces of a tip that is joined to the top of a hairpin-shaped filament.This layer is formed by adsorbing a selected metal via oxygen to a thickness which does not exceed the thickness of the monolayer of atoms.The metal will be selected from chromium, aluminum, cerium, magnesium, titanium, silicon, zirconium or hafnium.The field emission cathode features that the electrons are emitted in a concentrated manner from a particular crystal plane among the crystal planes of the tip.Therefore, it is possible to obtain a field emission cathode having very small emission angle of electrons.