Abstract: The invention provides a process for preparing an overvoltage protection material comprising: (i) preparing a mixture comprising a polymer binder precursor and a conductive material; and (ii) heating the mixture to cause reaction of the polymer binder precursor and generate a polymer matrix having conductive material dispersed therein, wherein the polymer binder precursor is chosen such that substantially no solvent is generated during the reaction.

Abstract: The invention provides a process for preparing an overvoltage protection material comprising: (i) preparing a mixture comprising a polymer binder precursor and a conductive material; and (ii) heating the mixture to cause reaction of the polymer binder precursor and generate a polymer matrix having conductive material dispersed therein, wherein the polymer binder precursor is chosen such that substantially no solvent is generated during the reaction.

Abstract: The invention provides a process for preparing an overvoltage protection material comprising: (i) preparing a mixture comprising a polymer binder precursor and a conductive material; and (ii) heating the mixture to cause reaction of the polymer binder precursor and generate a polymer matrix having conductive material dispersed therein, wherein the polymer binder precursor is chosen such that substantially no solvent is generated during the reaction.

Abstract: The invention provides a process for preparing an overvoltage protection material comprising: (i) preparing a mixture comprising a polymer binder precursor and a conductive material; and (ii) heating the mixture to cause reaction of the polymer binder precursor and generate a polymer matrix having conductive material dispersed therein, wherein the polymer binder precursor is chosen such that substantially no solvent is generated during the reaction.

Abstract: An electrical device which comprises first and second laminar electrodes and a laminar PTC resistive element sandwiched between them, the device comprising (a) a main portion which comprises a main part of the first electrode, a main part of the second electrode, and a main part of the resistive element; and (b) a first connection leg which extends away from the main portion and which comprises a first leg part of the first electrode which is integral with the main part of the first electrode, and a first leg part of the resistive element which is integral with the main part of the resistive element. Such devices can be secured to circuit boards in a variety of ways, and to elastically deformed terminals. Preferably preferred devices contain two laminar electrodes, with a PTC element between them, and a cross-conductor which passes through the thickness of the device and contacts one only of the two electrodes.

Abstract: The invention provides a process for preparing an overvoltage protection material comprising: (i) preparing a mixture comprising a polymer binder precursor and a conductive material; and (ii) heating the mixture to cause reaction of the polymer binder precursor and generate a polymer matrix having conductive material dispersed therein, wherein the polymer binder precursor is chosen such that substantially no solvent is generated during the reaction.

Abstract: The invention provides a process for preparing an overvoltage protection material comprising: (i) preparing a mixture comprising a polymer binder precursor and a conductive material; and (ii) heating the mixture to cause reaction of the polymer binder precursor and generate a polymer matrix having conductive material dispersed therein, wherein the polymer binder precursor is chosen such that substantially no solvent is generated during the reaction.

Abstract: The invention provides a process for preparing an overvoltage protection material comprising: (i) preparing a mixture comprising a polymer binder precursor and a conductive material; and (ii) heating the mixture to cause reaction of the polymer binder precursor and generate a polymer matrix having conductive material dispersed therein, wherein the polymer binder precursor is chosen such that substantially no solvent is generated during the reaction.

Abstract: The invention provides a process for preparing an overvoltage protection material comprising: (i) preparing a mixture comprising a polymer binder precursor and a conductive material; and (ii) heating the mixture to cause reaction of the polymer binder precursor and generate a polymer matrix having conductive material dispersed therein, wherein the polymer binder precursor is chosen such that substantially no solvent is generated during the reaction.

Abstract: The invention provides a process for preparing an overvoltage protection material comprising: (i) preparing a mixture comprising a polymer binder precursor and a conductive material; and (ii) heating the mixture to cause reaction of the polymer binder precursor and generate a polymer matrix having conductive material dispersed therein, wherein the polymer binder precursor is chosen such that substantially no solvent is generated during the reaction.

Abstract: An electrical device which comprises first and second laminar electrodes and a laminar PTC resistive element sandwiched between them, the device comprising

Abstract: The invention provides a process for preparing an overvoltage protection material comprising:

Abstract: An electrical device which comprises first and second laminar electrodes and a laminar PTC resistive element sandwiched between them, the device comprising: (a) a main portion which comprises a main part of the first electrode, a main part of the second electrode, and a main part of the resistive element; and (b) a first connection leg which extends away from the main portion and which comprises a first leg part of the first electrode which is integral with the main part of the first electrode, and a first leg part of the resistive element which is integral with the main part of the resistive element. Such devices can be secured to circuit boards in a variety of ways, and to elastically deformed terminals. Preferably preferred devices contain two laminar electrodes, with a PTC element between them, and a cross-conductor which passes through the thickness of the device and contacts one only of the two electrodes.

Abstract: The present invention provides a composite material comprising calcium carbonate particles dispersed within a polypropylene matrix, wherein the calcium carbonate particles have a size within the range of 1 to 100 nm and a filling ratio of less than about 30% by volume, more preferably less than about 10% by volume. The particles have a mean size of around 40 to 50 nm.

Abstract: The present invention provides a method for creating durable blends of polystyrene and polyolefin. The blends of the present invention have improved mechanical properties evidenced by measurement of impact strength, tensile strength, and elongation at break. Polyolefin is first crosslinked by creating a melt of polyolefin and a small amount of peroxide in a mixer at elevated temperature. The crosslinked polyolefin is then melt-blended with polystyrene at elevated temperature. Finally, a styrene-butadiene-styrene block copolymer is mixed into the melt. The method of the present invention can be applied to various blend systems of otherwise incompatible polymers provided it contains at least one component and a compatibilizer that are crosslinkable.

Abstract: There are disclosed novel composite materials in which polypropylene is reinforced by the inclusion of bamboo fibers. Preferably the polypropylene may be maleated prior to inclusion of the bamboo fibers in order to promote bonding between the bamboo fibers and the polypropylene matrix.

Abstract: A circuit protection device which comprises first and second laminar electrodes; a laminar PTC conductive polymer resistive element sandwiched between the electrodes; a third laminar conductive member which is secured to the same face of the PTC element as the second electrode but is separated therefrom; and an electrical connector which connects the third conductive member and the first electrode. This permits connection to both electrodes from the same side of the device, so that the device can be connected flat on a printed circuit board, with the first electrode on top, without any need for leads. The connector is preferably a cross-conductor which passes through an aperture in the PTC element, because this makes it possible to carry out the steps for preparing the devices on an assembly which corresponds to a number of individual devices, with division of the assembly as the final step.

Abstract: A conductive polymer composition which has a resistivity of less than 10 ohm-cm and which exhibits PTC behavior comprises a polymeric component and a particulate conductive filler. The polymeric component comprises a first crystalline fluorinated polymer having a first melting point T.sub.m1 and a second crystalline fluorinated polymer having a second melting point T.sub.m2 which is from (T.sub.m1 +25).degree. C. to (T.sub.m1 +100).degree. C. The composition exhibits one of a number of characteristics, including a relatively high PTC anomaly. The composition is useful in circuit protection devices to be used at high ambient conditions.

Abstract: An electrical device in which a conductive terminal is physically and electrically attached directly or indirectly to a face of a laminar PTC resistive element. The terminal comprises a laminar portion and a non-laminar shaped portion which lies within a projection of the periphery of the PTC resistive element. The shaped portion serves to improve thermal transfer between the PTC element and the atmosphere surrounding the device. Devices of the invention are useful as circuit protection devices.

Abstract: An electrical device in which a first connection element is in electrical contact with a resistive element. The first connection element defines a cavity into which, when the cavity is empty, a second connection element can be inserted. The second connection element, which may be connected to a source of electrical power, is partially within the cavity, makes physical and electrical contact with the first connection element, and protrudes from the cavity. Such devices can be made in a continuous process by a method of the invention. They are particularly suitable for insertion into a circuit board.