Patent ID: 6861021

Claim:
A molding tool construction, comprising: a substrate; a first insulating layer having an electrical resistivity of at least about 10 10 ohm-centimeters and thermal conductivity of about 0.2 to about 5 watts/(meter-kelvin); a heating element; a second insulating layer having an electrical resistivity of at least about 10 10 ohm-centimeters and a thermal conductivity of at least about 5 watts/(meter/kelvin); and a first molding layer having a specific heat capacity of about 100 to about 2,500 joule/(kilogram-kelvin); and optionally, a second molding layer; said first insulating layer is interposed between the substrate and the heating element, and said second insulating layer is interposed between the heating element and the first molding layer, and said first molding layer is interposed between the second insulating layer and the second molding layer, if present; and further wherein the first insulating layer comprises a material selected from the group consisting of alumina, yttria, yttria-modified zirconia, and combinations comprising at least one of the foregoing materials; the second insulting layer comprises a material selected from the group consisting of aluminum nitride, mullite, zirconia, and combinations comprising at least one of the foregoing materials; the first molding layer comprises a material selected from the group consisting of tungsten, titanium, molybdenum, alloys comprising at least one of the foregoing metals, and combinations comprising at least one of the foregoing materials; the second molding layer, if present, comprises a material selected from the group consisting of nickel, chromium, copper, alloys comprising at least one of the foregoing materials, and combinations comprising at least one of the foregoing materials.