Abstract: Binders for manufacture of precision casting molds are provided, which are highly stable and are advantageous in that these may impart a high strength to the green molds as obtained by forming an accumulative refractory coat layer on a water-soluble pattern and then taking off the pattern from the coat layer, that no interlayer cleavage occurs in the accumulative coat layer when the pattern is taken off in the formation of the green mold, that the binders may impart a high strength to fired molds, that the castings as obtained by the use of the present fired molds are free from the surface roughness and other surface faults and that the dimension accuracy of the castings is not deteriorated at all by the use of the present binders.The binders of the present invention are characterized by containing the following components (a), (b) and (c) and optionally (d):(a) an organo-silicasol capable of providing 5-50 parts by weight of SiO.sub.

Abstract: A binder for manufacture of a precision casting mold comprising a transparent solution containing an alkyl orthosilicate or an alkyl polysilicate having a polymerization degree of 2 to 10, and an amino-alkoxide of a metal selected from a group consisting of titanium, zirconium, tin and aluminum or a mixture thereof in the mol ratio (Si/N) of 0.01 to 1.0 calculated in terms of the silicon atom contained in the silicate and the basic nitrogen atom contained in the amino-alkoxide. This binder is excellent in preservation stability and workability and does not dissolve the surface of a water-soluble pattern.

Abstract: Disclosed is a positively charged antimony pentoxide sol, comprising colloidal particles of antimony pentoxide sol coated on their surfaces with at least one of trivalent and tetravalent metals, the content of the metals being 1 to 50% by weight in terms of the metal oxide based on antimony pentoxide in the antimony pentoxide sol.When the positively charged antimony pentoxide sol of this invention is mixed with a cationic resin emulsion or an aqueous solution of a cationic water-soluble polymer, no agglomeration occurs and also, when it is added into an aqueous solution of an inorganic acid such as hydrochloric acid, sulfuric acid, nitric acid, etc., or an organic acid such as acetic acid, propionic acid, oxalic acid, maleic acid, etc.

Abstract: Antimony pentoxide-containing flame retardant for halogen-containing vinyl resins which comprises, with respect to 100 parts by weight of Sb.sub.2 O.sub.5, (A) 3 to 20 parts by weight of an alkali metal in terms of M.sub.2 O wherein M represents an alkali metal, (B) 1 to 25 parts by weight of an alkaline earth metal in terms of M'O wherein M' represents an alkaline earth metal, and (C) 0.04 to 3 parts by weight of a compound selected from the group consisting of phosphoric acid, an ammonium salt of phosphoric acid, and an alkali metal salt of phosphoric acid, in terms of P.sub.2 O.sub.5, as well as a method for preparing the same.The flame retardant according to this invention does not impair, the transparency, the thermal stability, or the bleeding resistance of the halogen-containing vinyl resins.

Abstract: A process for preparing an antimony pentoxide sol, which comprises dispersing sodium antimonate in water, reacting the sodium antimonate with a monovalent or divalent inorganic acid added in a stoichiometrical amount of 0.7 time to 5 times the amount of the sodium antimonate to form the sodium salt of said inorganic acid and an antimony pentoxide gel, separating and water washing said gel, dispersing said gel in water, and peptizing said gel dispersed in water by adding an organic base in an amount to provide a stoichiometrical amount of base / Sb.sub.2 O.sub.5 of from 0.03 to 1.

Abstract: A flame retarded resin composition, which comprises 100 parts by weight of a synthetic resin, a sodium antimony phosphate amorphous product mixed in an amount of 0.05 to 30 parts by weight based on said synthetic resin, and optionally a flame retardant such as an organic halogenated compound further mixed in an amount of 1 to 30 parts by weight based on said synthetic resin. The resin composition has good transparency and coloring property.