Abstract: A PTC material composition for making a PTC circuit protection device comprises a PTC polymer unit and a conductive filler containing a plurality of titanium carbide particles. The titanium carbide particles have a residual oxygen content greater than 0.3 wt % based on the weight of the titanium carbide particles.

Abstract: A method for making a positive temperature coefficient device includes: (a) forming a crosslinkable preform of a positive temperature coefficient polymer composition containing a polymer system and a conductive filler; (b) attaching a pair of electrodes to the preform; (c) soldering a pair of conductive leads to the electrodes using a lead-free solder paste having a melting point greater than 210° C.; and (d) crosslinking the crosslinkable preform after step (c).

Abstract: A PTC circuit protection device includes a PTC polymer material and two electrodes attached to the PTC polymer material. The PTC polymer material includes a polymer matrix and a particulate conductive filler dispersed in the polymer matrix. The polymermatrix is made from a polymer composition that contains a primary polymer unit and a reinforcing polyolefin. The primary polymer unit contains a base polyolefin and optionally a grafted polyolefin. The reinforcing polyolefin has a weight average molecular weight greater than that of the base polyolefin. The primary polymer unit and the reinforcing polyolefin are co-melted together and then solidified to form the polymer matrix. The base polyolefin has a melt flow rate ranging from 10 g/10 min to 100 g/10 min, and the reinforcing polyolefin has a melt flow rate ranging from 0.01 g/10 min to 1 g/10 min.

Abstract: A PTC material composition for making a PTC circuit protection device comprises a PTC polymer unit and a conductive filler containing a plurality of titanium carbide particles. The titanium carbide particles have a residual oxygen content greater than 0.3 wt % based on the weight of the titanium carbide particles.

Abstract: A positive temperature coefficient polymer composition includes a polymer system and a conductive particulate filler. The polymer system includes a non-ionic copolymer of a substituted or non-substituted olefin monomer and an anhydride monomer. The olefin monomer and the anhydride monomer form a linear polymer chain.

Abstract: A method for making a positive temperature coefficient device includes: (a) forming a crosslinkable preform of a positive temperature coefficient polymer composition containing a polymer system and a conductive filler; (b) attaching a pair of electrodes to the preform; (c) soldering a pair of conductive leads to the electrodes using a lead-free solder paste having a melting point greater than 210° C.; and (d) crosslinking the crosslinkable preform after step (c).

Abstract: A positive temperature coefficient polymer composition includes a polymer system and a conductive particulate filler. The polymer system includes a non-ionic copolymer of a substituted or non-substituted olefin monomer and an anhydride monomer. The olefin monomer and the anhydride monomer form a linear polymer chain.

Abstract: A PTC polymer composition contains: (a) a non-elastomeric polymer mixture in an amount from 20 wt % to 80 wt % based on the weight of the polymer composition; (b) a conductive particulate material in an amount from 20 wt % to 60 wt % based on the weight of the polymer composition; (c) a voltage resistance-enhancing agent that contains particulate metal oxide material in an amount from 1 wt % to 30 wt % based on the weight of the polymer composition; and (d) a polymer stabilizer that contains a thermoplastic elastomer in an amount from 1 wt % to 30 wt % based on the weight of the polymer composition.

Abstract: A PTC circuit protection device has a resistivity at 20° C. of less than 10 ohm-cm and is made from a PTC polymer composition that contains: 40-70 vol % of a non-cross-linked polyvinylidene fluoride (PVDF) or a cross-linked polyvinylidene fluoride formed by cross-linking the non-cross-linked polyvinylidene fluoride by irradiation to a dosage less than 8 Mrads; and 30-60 vol % of a particulate conductive filler. The non-cross-linked polyvinylidene fluoride has a melting flow rate (MFR) of less than 120 g/10 min.

Abstract: A PTC polymer composition contains: (a) a non-elastomeric polymer mixture in an amount from 20 wt % to 80 wt % based on the weight of the polymer composition; (b) a conductive particulate material in an amount from 20 wt % to 60 wt % based on the weight of the polymer composition; (c) a voltage resistance-enhancing agent that contains particulate metal oxide material in an amount from 1 wt % to 30 wt % based on the weight of the polymer composition; and (d) a polymer stabilizer that contains a thermoplastic elastomer in an amount from 1 wt % to 30 wt % based on the weight of the polymer composition.

Abstract: A PTC polymer composition comprises a polymer material, a conductive particulate material dispersed in the polymer material, and a non-conductive filler. The polymer material contains a crystalline grafted polymer selected from the group consisting of grafted polyolefin, grafted polyolefin derivatives, and grafted copolymers of polyolefin and polyolefin derivatives. The grafted polymer is grafted by a polar group selected from the group consisting of carboxylic acids and derivatives thereof. The non-conductive filler comprises a particulate metal oxide material which is dispersed in the polymer material.

Abstract: A PTC polymer composition contains a polymer mixture, a conductive particulate material, and a voltage resistance-enhancing agent of particulate metal oxide for enhancing voltage resistance of the polymer composition. The polymer mixture contains a crystalline grafted polymer and a crystalline non-grafted polymer.

Abstract: A process for making surface mountable electrical devices includes the steps of laminating two PTC sheets, two inner metal foil sheets, and two outer metal foil sheets to form a laminate such that the inner metal foil sheets are sandwiched between the PTC sheets and overlap each other and that the PTC sheets are bonded to each other, forming patterns of slits in the outer metal foil sheets, forming bores in the laminate along cutting lines, forming conductive transverse layers in interiors of the bores, and cutting the laminate along the cutting lines.

Abstract: A process for making surface mountable electrical devices includes the steps of laminating two PTC sheets, two inner metal foil sheets, and two outer metal foil sheets to form a laminate such that the inner metal foil sheets are sandwiched between the PTC sheets and overlap each other and that the PTC sheets are bonded to each other, forming patterns of slits in the outer metal foil sheets, forming bores in the laminate along cutting lines, forming conductive transverse layers in interiors of the bores, and cutting the laminate along the cutting lines.

Abstract: A surface mountable electrical devices includes a laminate body having a plurality of stacked PTC sheets, two overlapping metal foil sheets sandwiched between two adjacent ones of the PTC sheets, a conductive first electrode layer, a conductive second electrode layer spaced apart from the first electrode layer, and a conductive third electrode layer. The two adjacent ones of the PTC sheets have contact faces with inlaid portions respectively inlaid with the metal foil sheets and non-inlaid portions bonded to each other. At least a conductive transverse layer interconnects the first and third electrode layers and the metal foil sheets.