Thermally insulated structural members, and doors and windows incorporating them

A thermally insulated structural member for a door or window, comprising:

• a frame comprising a metal;
• and
• an insulation bar at least partially enclosed by the frame;
• wherein the insulation bar comprises a thermoplastic composition comprising
• about 55 to about 95 weight percent of a compatibilized
• polyamide-poly(arylene ether) composition, and
• about 5 to about 45 weight percent of hollow glass beads, wherein the hollow glass beads have
• a volume-average diameter of about 20 to about 60 micrometers,
• a true density of about 0.3 to about 0.5 grams per milliliter, and
• an isostatic crush strength of about 30 to about 60 megapascals;
• wherein the thermoplastic composition comprises less than 5 weight percent of fibrous reinforcement;
• wherein the insulation bar comprises a wall having a thickness of about 0.2 to about 4 millimeters;
• wherein the compatibilized polyamide-poly(arylene ether) composition is the product of melt blending components comprising
• about 32 to about 45 weight percent of the poly(arylene ether);
• wherein the poly(arylene ether) comprises a poly(2,6-dimethyl-1,4-phenylene ether) having an intrinsic viscosity of about 0.3 to about 0.6 deciliter per gram, measured at 25° C. in chloroform,
• about 32 to about 45 weight percent of the polyamide;
• wherein the polyamide comprises a polyamide-6,6,
• about 0.15 to about 2 weight percent of a compatibilizing agent for the poly(2,6-dimethyl-1,4-phenylene ether) and the polyamide-6,6, and about 15 to about 25 weight percent of the hollow glass beads;
• wherein the thermoplastic composition has a density of about 0.8 to about 1 gram per milliliter;
• wherein the thermoplastic composition excludes foaming agents and their residue;
• and
• wherein the thermoplastic composition has a thermal conductivity less than or equal to 0.2 watts per meter-Kelvin, measured according to ASTM E 1530 at 50° C. using a disc measuring 40 millimeters in diameter and 3.4 millimeters in thickness.

A method of reducing the thermal conductivity of a thermally insulated structural member for a door or window, comprising:

• at least partially enclosing in a metal frame an insulation bar comprising a thermoplastic composition comprising
• about 55 to about 95 weight percent of a compatibilized
• polyamide-poly(arylene ether) composition, and
• about 5 to about 45 weight percent of hollow glass beads, wherein the hollow glass beads have
• a volume-average diameter of about 20 to about 60 micrometers,
• a true density of about 0.3 to about 0.5 grams per milliliter, and
• an isostatic crush strength of about 30 to about 60 megapascals;
• wherein the thermoplastic composition comprises less than 5 weight percent of fibrous reinforcement;
• wherein the thermoplastic composition excludes foaming agents and their residue;
• and
• wherein the thermoplastic composition has a density of about 0.8 to about 1 gram per milliliter.