Abstract: [Problems] To provide a resin composition having excellent flame retardancy and a fiber having excellent flame retardancy, without deteriorating conventional mechanical properties by adding a small amount of a flame-retardant additive. [Means for Resolution] A flame-retardant resin composition comprising a resin and composite particles in an amount of 1% by weight or more based on the resin, which are mainly composed of titanium dioxide and silicon dioxide and have a titanium dioxide content of 10 to 30% by weight and a silicon dioxide content of 70 to 90% by weight, a flame-retardant fiber obtained by fiberizing this flame-retardant resin composition, a heat-resistant cloth using this flame-retardant fiber, and further, protective clothing using this cloth.

Abstract: The heterocycle-containing aromatic polyamide fibers of the invention are excellent in balance among mechanical characteristics, particularly balance among tensile strength, initial modulus and strength in the direction perpendicular to the fiber axis, exhibit a high strength holding ratio under heat and humidity, and are excellent in flame retardancy, bulletproofness and cutting resistance, as compared to conventional aromatic polyamide fibers, and therefore can be favorably used in fields with severe mechanical characteristics and have stability to environmental variation. Accordingly, the heterocycle-containing aromatic polyamide fibers of the invention can be favorably used, for example, in fields including protective equipment, such as a helmet, a bulletproof vest and the like, a chassis for an automobile, a ship and the like, an electric insulating material, such as a printed circuit board and the like, and other various fields.

Abstract: An optically active compound represented by formula (I): ##STR1## wherein R.sup.1 represents an alkyl group having from 6 to 18 carbon atoms or an alkoxy group having from 6 to 18 carbon atoms; A represents ##STR2## or ##STR3## wherein ring ##STR4## represents a nitrogen-containing hetero-aromatic ring; n and m each represents 0 or 1; R.sup.2 represents an alkyl group having from 1 to 12 carbon atoms; and C* is an asymmetric carbon atom. The compound of formula (I) exhibits excellent physicochemical stability, a low temperature range for the chiral smectic C phase when used either alone or in combination with other compounds, and a rapid response.