초록 ▼

A heat-sensitive resistive compound is formed by a mixture of particles of at least one electrically conducting material (A) in the solid state and of at least one resin (B) in the solid state; the mixture is dispersed in at least one liquid solvent (C); the percentage by weight of the electrically

A heat-sensitive resistive compound is formed by a mixture of particles of at least one electrically conducting material (A) in the solid state and of at least one resin (B) in the solid state; the mixture is dispersed in at least one liquid solvent (C); the percentage by weight of the electrically conducting material (A) with respect to the total weight of the anhydrous compound is 5% to 70%. The resistance of the compound after a furnace process increases, as the temperatures rises, in a substantially linear manner for temperatures that are approximately lower than or equal to 70°C. and in a substantially exponential manner for temperatures that are approximately higher than 70°C. The relative increase in the resistance of the compound with respect to its resistance at ambient temperature is at least 3 for temperatures higher than 100°C. and at least 5 for temperatures above 115°C. The method for providing a PTC device includes the deposition, by printing or screen-printing, of the resistive compound on a flexible or rigid laminar support made of insulating material (2) along an electric path (3) that connects conducting paths (6) which form electrodes; the compound is deposited when cold and is subjected to one or more furnace processes at a temperature that is at least equal to 110°C. for a period and a number of times that are sufficient to achieve the complete evaporation of the solvent (C) and the adhesion of the resin (B) to the substrate.

대표청구항 ▼

A method of preparation of a heat-sensitive resistive compound, particularly suitable for PTC devices, comprising the steps of preparing an anhydrous mixture of particles of at least one electrically conducting material (A) in the solid state and of at least one synthetic resin (B) in the solid stat

A method of preparation of a heat-sensitive resistive compound, particularly suitable for PTC devices, comprising the steps of preparing an anhydrous mixture of particles of at least one electrically conducting material (A) in the solid state and of at least one synthetic resin (B) in the solid state, dispersing and homogenizing said anhydrous mixture in a transient carrier (C), wherein the percentage by weight of said electrically conducting material (A) with respect to the total weight of the anhydrous mixture is from 5% to 70%, characterized in that said at least one electrical conducting material (A) comprises particles of a single carbon black of average size approximately in the range from 0.1 m100 m20 m200 m