Abstract: The object of the present invention is to provide a flame retardant agent which can provide with high flame retardance with a very small amount of additives without impairing basic physical properties of resins and is highly safe and harmless to humans and environment without substantially having negative effect thereon, because the flame retardant agent does not contain halogen elements and phosphorus elements. To this end, the invention provides a flame retardant agent which comprises a polyvalent phenol compound, a saccharide compound, and a fatty acid compound and also provides a flame-retardant resin composition which comprises the flame retardant agent and a resin.

Abstract: An agent for imparting flame retardancy to a thermoplastic resin contains a polyhydric phenol such as a tannin compound as an effective component. The thermal stability of the thermoplastic resin can be improved so as to elevate the decomposition temperature of the thermoplastic resin if a small amount of the flame retardancy imparting agent is added to the thermoplastic resin so as to suppress the combustibility of the thermoplastic resin.

Abstract: Provided is an additive for a thermoplastic resin prepared by mixing tannin with a coupling agent, and the above additive inhibits the thermoplastic resin from being reduced in a molecular weight in heating and melting and achieves heat stabilization of the thermoplastic resin. Accordingly, it becomes possible to recycle the molded articles.

Abstract: The present invention provides a resin additive obtained by subjecting inorganic particles to surface treatment with catechin, a resin additive obtained by subjecting inorganic particles to surface treatment with catechin and further subjecting them to surface treatment with a coupling agent or a resin additive obtained by subjecting inorganic particles to surface treatment with catechin and then subjecting them to surface treatment with a phenone compound or saccharides, followed by further subjecting them to surface treatment with a coupling agent. These resin additives have the effect to inhibit a reduction in the molecular weight of a thermoplastic resin in heating and melting or inhibit a reduction not only in the molecular weight but also the IZOT impact strength.

Abstract: Tannin obtained by dehydrating it by heating up to 70 to 230° C. to subject it to polycondensation is used as a resin additive.

Abstract: The present invention provides a resin additive obtained by subjecting inorganic particles of silica or alumina to surface treatment with tannic acid and further subjecting them to surface treatment with a coupling agent, or subjecting inorganic particles to surface treatment with tannic acid and then subjecting them to surface treatment with a phenone compound or saccharides, followed by further subjecting them to surface treatment with a coupling agent. The above resin additive has an effect to provide a thermoplastic resin with heat stability in heating and melting the resin and prevent a reduction in the IZOT impact strength.

Abstract: The present invention relates to silicon oxide having tannic acid adsorbed thereon, which is used as a degradation-preventing additive for a thermoplastic resin. This can be obtained by treating 100 parts by weight of silicon oxide with a solution containing 0.5 to 8.0 parts by weight of tannic acid to allow tannic acid to be adsorbed thereon. A reduction (degradation) in a molecular weight of a thermoplastic resin brought about by hydrolysis caused by moisture for a long period of time or thermal decomposition in molding can be inhibited by adding 0.2 to 3.4 % of the tannic acid-adsorbed silicon oxide thus obtained to a thermoplastic resin.

Abstract: A polycarbonate resin composition comprising substantially:94.0-99.5% by weight of a polycarbonate resin, and0.5-6.0% by weight of zeolite having tannic acid adsorbed thereon.In this polycarbonate resin composition, the molecular weight reduction of polycarbonate resin is suppressed.