The B. F. Goodrich Company

Rjf International Corporation

Flexmag Industries, Inc.

Raymond C Srail

Thomas R Szczepanski

Richard A Glover

Tiong H Kuan

Eric Martin Weissman

Frederic W Kunig

Roy L Orndorff, Jr

A process and apparatus for permitting the magnetization of flexible hard magnetic materials in the form of sheets or strips, such as magnetic rubber, wherein opposing arrays formed from alternating magnetic disks and flux conducting elements are use in sets of two with opposing polar moments such as to induce a magnetic flux in the gap between the discs. The width of the magnetic disk and flux conducting elements, respectively, are selected to optimize the magnetic pull strength of the material. At the array ends are flux conducting elements that are about 1/2 (i.e., from about 0.25 to about 0.75, and preferably from about 0.4 to 0.6) of the width of the internal flux conducting elements. A material to be magnetized is passed between the array sets in contrast with both disks and consequently imprinted with magnetic poles. The magnetized properties of the material is enhanced by passing the material through a second set of arrays which are axially offset with respect to the first set of arrays. This enhances the residual induction of the sample, the shape of the Br.sup.2 versus distance curve, and significantly improves the pull strength of the material. A device is provided for the production of the material, and further can be used without modification to imprint non-traversing magnetization by biasing the material to one of the arrays of the second, i.e. exiting, set of arrays.

Magnetized material having enhanced magnetic pull strength and a process

A process and apparatus for permitting the magnetization of flexible hard magnetic materials in the form of sheets or strips, such as magnetic rubber, wherein opposing arrays formed from alternating magnetic disks and flux conducting elements are use in sets of two with opposing polar moments such as to induce a magnetic flux in the gap between the discs. The width of the magnetic disk and flux conducting elements, respectively, are selected to optimize the magnetic pull strength of the material. At the array ends are flux conducting elements that are about 1/2 (i.e., from about 0.25 to about 0.75, and preferably from about 0.4 to 0.6) of the width of the internal flux conducting elements. A material to be magnetized is passed between the array sets in contrast with both disks and consequently imprinted with magnetic poles. The magnetized properties of the material is enhanced by passing the material through a second set of arrays which are axially offset with respect to the first set of arrays. This enhances the residual induction of the sample, the shape of the Br.sup.2 versus distance curve, and significantly improves the pull strength of the material. A device is provided for the production of the material, and further can be used without modification to imprint nontraversing magnetization by biasing the material to one of the arrays of the second, i.e. exiting, set of arrays.

Magnetized material having enhanced magnetic pull strength and process

Impact resistant and flame retardant polymer composition, slab-like rectangular solid made of said composition, and composite laminate article having at least one layer of said composition. The polymer composition comprises a maximum of 86 volume percent of ultra high molecular weight polyethylene (UHMWPE), a minimum of 4.40 volume percent of a flame retardant additive or mixture thereof, and a minimum of 6 volume percent of chopped reinforcing fibers, all volumes referring to the densified (molded) state. In addition the bulk volume of the chopped reinforcing fibers, as measured by a tapped density test, must be a minimum of 27 percent of the final molded volume of the composition. The maximum volume % loading of the additives is limited by the requirement that the notched Izod impact strength is a minimum of 7 ft.-lb per inch width. The preferred flame retardant additive is essentially a water insoluble form of ammonium polyphosphate having a water solubility not exceeding 1 gram per 100 grams of water, and the preferred reinforcing fibers are chopped glass fibers about 1/8 to 1/4' inch in length.

Compression molded flame retardant and high impact strength ultra high

A flexible magnetic blend composition is provided which is comprised of high energy rare earth magnetic particles in a flexible high temperature resistant and oil resistant polymer binder. The binder system preferably comprises a highly saturated nitrile rubber (HSN) or a polymer alloy of the same in which a HSN is the major polymer and also contains additives which are compatible with processing, subsequent electron beam curing, and final product performance. The binder system is high loaded, usually from about 50 to about 70 volume percent, with the high energy rare earth magnetic particles, which can produce bonded magnets with a maximum energy product of at least 2.5 megagauss-oersteds, a remenance, B.sub.r of at least 3400 gauss, a coercive force, Hc, of at least 2900 oersteds and an intrinsic coercivity, Hci, of at least 5000 oersteds. The process for production of this system involves the binder system and rare earth magnetic particles being mixed and then formed into a final geometry before being cured by high voltage electron beam radiation. The electron beam curing in the solid state fixes dimensional stability, magnetic properties, and oil, solvent and chemical resistance of the part even when exposed to subsequent hostile temperature environments of 100.degree. C. or higher. Further, the HSN binder system reduces oxidation of the rare earth magnetic particles from subsequent hot air aging when compared to conventional nitrile elastomer binder system. Any off geometry parts or trim produced in the process prior to radiation curing can be recycled through processing several times without fear of premature cure.

Flexible high energy magnetic blend compositions based on rare earth

A flexible magnetic blend composition is provided which is comprised of high energy ferrite magnetic particles in a flexible high temperature resistant and oil resistant polymer binder. The binder system is preferably a highly saturated nitrile rubber (HSN) or a polymer alloy of the same in which a HSN is the major polymer containing alloying polymers and/or additives which are compatible with processing, subsequent electron beam curing, and final product performance. The binder system is highly loaded usually from 55 to 65 volume percent with the high energy ferrite particles, i.e., barium and/or strontium ferrite particles, which can produce bonded magnets with a maximum energy product of at least 1.0 megagauss-oersteds, a remenance, Br, of at least 2000 gauss, a coercive force, H.sub.c, of at least 1800 oersteds, and an intrinsic coercivity, H.sub.ci, of at least 2000 oersteds. The process for production of this system involves the binder system and ferrite particles being mixed, the ferrite particles oriented in a preferred direction during processing, then formed into a final geometry before being cured by high voltage electron beam radiation, preferably in excess of 3,000,000 electron volts. The electron beam curing in the solid state fixes dimensional stability, magnetic properties, oil, solvent, and chemical resistance of the part even when exposed to subsequent hostile temperature environments of 125.degree. C. or higher. Any off geometry parts or trim produced in the process prior to radiation curing can be recycled through processing several times without fear of premature cure.

Flexible high energy magnetic blend compositions based on ferrite

Crystalline elastomeric network compositions are transformable from their original cured shape into an altered shape and subsequently back to their original shape. The transformation process, which is repeatable, is effected by the simultaneous application of heat and deformation forces. The amount of heat required, expressed in terms of temperature, is relatively low. The shape-transformable compositions of the present invention are single phase blends of one or more crystalline polymers and one or more elastomer polymers. The compositions generally have a single broad endotherm due probably to the co-crystallization of the different crystalline segments, a low glass transition temperature, and a low transformation temperature, that is generally less than 100.degree. C.

Growing community of inventors

Parma, OH, United States of America

Raymond C Srail