Abstract: A method in which an aqueous water-soluble compound solution containing at least one impurity in a slight amount is passed through a column packed with an adsorbent onto which the impurity is selectively adsorbed to thereby remove the impurity from the aqueous solution, wherein an abnormal phenomenon in adsorption chromatography is caused to obtain an elute fraction having a higher concentration of the trace impurity than the raw solution and this fraction is removed. Thus, the trace impurity can be efficiently removed and the water-soluble compound can be obtained in a high-purity state. Applying this method to aqueous sodium chloride solutions gives sodium chloride crystals reduced in impurity concentration. Dissolving such sodium chloride crystals, which have a low potassium ion concentration, in water provides an aqueous sodium chloride solution for medical use.

Abstract: There is provided a transparent silicone film-forming composition which forms an ultraviolet-absorbing and infrared-screening film exhibiting a film hardness of 6H to 9H or more after curing on a transparent substrate such as glass and plastic. The transparent silicone film-forming composition contains a reaction product of an alkoxysilane having an epoxy group and alkoxysilane having an amino group with an active hydrogen, an acid catalyst, a finely ground ITO cocatalyst and at least one solvent selected from organic solvents. The transparent silicone film-forming composition can also contain a reaction product of an alkoxysilane having an epoxy group and alkoxysilane having an amino group with an active hydrogen as well as tri- or dialkyloxysilane mixed with monoalkoxysilane and/or glycidesilane, an acid catalyst, a finely ground ITO cocatalyst and at least one solvent selected from organic solvents.

Abstract: A colored, transparent film-forming composition, which is made up of (a) a reaction product of an epoxy group-containing alkoxysilane (a-1) and an amino group-containing alkoxysilane (a-2) having active hydrogen therein, (b) an acid catalyst, (c) an alkali-soluble UV absorber, (d) at least one solvent selected from organic solvents having a boiling point of 100 to 250° C., and (e) a dye and/or a pigment, has a good coating performance and room temperature curing characteristic and can provide a film having good film strength and film removability after use. The coating method of the composition and the removing method of the film obtained from the composition are also described.

Abstract: There is provided a transparent silicone film-forming composition which forms a ultraviolet absorbing and infrared screening film exhibiting film hardness of 6H to 9H or more after curing on a transparent substrate such as glass and plastic. A transparent silicone film-forming composition comprises a reaction product of alkoxysilane having an epoxy group and alkoxylsilane having an amino group with active hydrogen, an acid catalyst, a finely ground ITO cocatalyst and at least one solvent selected from organic solvents. A transparent silicone film-forming composition comprising a reaction product of alkoxysilane having an epoxy group and alkoxylsilane having an amino group with active hydrogen as well as tri- or dialkoxysilane mixed with monoalkoxysilane and/or glycidsilane, an acid catalyst, a finely ground ITO cocatalyst and at least one solvent selected from organic solvents.

Abstract: A colored, transparent film-forming composition, which comprises (a) a reaction product of an epoxy group-containing alkoxysilane (a-1) and an amino group-containing alkoxysilane (a-2) having active hydrogen therein, (b) an acid catalyst, (c) an alkali-soluble UV absorber, (d) at least one solvent selected from organic solvents having a boiling point of 100 to 250° C., and (e) a dye and/or a pigment, has a good coating performance, a good room temperature curing characteristic and can provide a film having good film strength and good film removability after use. The coating method of the composition and the removing method of the film obtained from the composition are also described.

Abstract: A biodegradable nonwoven fabric and molded vessel suitable to throwaway use such as in domestic, wrapping, agricultural, gardening, and civil engineering field. A web of cellulose-based fibers are combined with chitosan salt and an interfiber binder comprising a combination of chitosan salt and fine cellulose, or by combined use of the interfiber binder and physical combining techniques. They are naturally decomposed by microorganisms in the soil and can dissolve the polution problems.

Abstract: A biodegradable film or the like shaped article is formed from a composition including 100 parts by weight of cellulose fibers having a length of 3 mm or less and a diameter of 50 .mu.m or less, 10-600 parts by weight of a thermoplastic resin and 2-100 parts by weight of chitosan. A mixture containing (a) an aqueous solution of an acid salt of chitosan, (b) an aqueous dispersion or solution of a thermoplastic resin and (c) fine cellulose fibers is dried and shaped to obtain such a biodegradable shaped article.

Abstract: A biodegradable sheet is produced from an aqueous dispersion containing finely cut cellulose fibers and chitosan. The dispersion is maintained at a temperature T.sub.1 .degree.C. which is within the following range:t.ltoreq.T.sub.1 .ltoreq.t+30wherein t is the boiling point (.degree.C.) of water at a given reduced pressure and is continuously introduced into a defoaming zone maintained at the given reduced pressure and at a temperature within the same range as that of T.sub.1. In the defoaming zone, the dispersion is formed into a downwardly flowing laminar flow so that air entrapped therein is effectively removed therefrom. The defoamed dispersion is then passed through a die and is molded into a sheet which is subsequently dried.