Abstract: A toothbrush to automatically guide the user to simultaneously clean a tooth surface, the cusps, and the gingival sulcus at approximately 45 degrees. The bristle elements are arranged generally in two banks with the free ends of the bristle elements in the first bank extending convergingly with the free ends of the bristle elements in the second bank to provide a V-shaped tooth receiving channel having an acute included angle of from about 10 to 55 degrees. The bristle elements in the respective banks which are closest together, which is at about the apex of the V-shaped tooth receiving channel, extend into contact with one another at the bristle tips to define therebetween a doublet of mutually supported bristle elements. This doublet provides a stiff cleaning element for the nooks and crannies of the cusps of the teeth.

Abstract: A solar collector device comprising a truncated dome shaped absorber with inner and outer wall defining an annular space wherein fluid to be heated passes is disclosed. The absorber is placed within a curved surfaced container which is transparent to infrared radiation. In one embodiment the surface of the container opposite the transparent side is provided with a reflective coating and the container is preferably substantially evacuated to reduce heat transfer from the absorber. In another embodiment the northerly side of the absorber is thermally insulated. The absorber is preferably black surfaced and when constructed of coiled tubing, the tubing is coiled in a cylindrical or domed configuration of one or more coils, and solar reflectors are positioned to provide reflected radiation to those sides of the absorber not receiving direct sunshine.

Abstract: A novel dental tape for cleaning between the teeth is described. The tape is made of strong, flexible, non-tacky, non-toxic polymer which has rows of protuberances on which foreign particles between the teeth get caught and are removed as the tape is moved between the teeth.

Abstract: A method of preparing nitrile elastomer surfaces for bonding by epoxy adhves is presented. A treating solution comprising a dilute concentration of a mineral acid such as HCl in a carrier comprising water and either alcohol or ketones is prepared. The treating solution is applied to the elastomer surface with the surface being hydrolyzed in a mild manner thereby providing an improved adherable surface for covalent bonding by epoxy adhesives. A surfactant can be added to the treating solution for cleaning the surface to enhance the surface treatment.

Abstract: A method of preparing nitrile elastomer surfaces for bonding by epoxy adhves is presented. A treating solution comprising a dilute concentration of a mineral acid such as HCl in a carrier comprising water and either alcohol or ketones is prepared. The treating solution is applied to the elastomer surface with the surface being hydrolyzed in a mild manner thereby providing an improved adherable surface for covalent bonding by epoxy adhesives. A surfactant can be added to the treating solution for cleaning the surface to enhance the surface treatment.

Abstract: Unvulcanized or partially vulcanized rubber is coated with a coating poly capable of co-vulcanizing with the rubber and having functional groups capable of reacting with an adhesive. The coated rubber is then subjected to vulcanizing conditions. When the treated rubber surface is bonded to an adhesive, the functional groups react with the adhesive forming strong bonds.

Abstract: This invention discloses a method for converting a nitrile rubber substrate urface to a chemically active surface whereupon said surface reacts with an adhesive to form a permanent bond with said adhesive. The nitrile rubber substrate surface is so converted by treatment with a dilute mineral acid.

Abstract: A material which has two reactive groups, one of which is reactive with the irst of two dissimilar polymeric materials but not the second and the other of which is reactive with the second but not the first, is utilized to bind layers of the two polymeric materials together. The groups that are reactive with the first polymeric material are reacted with it as a layer of that material cures. Then a layer of the uncured second polymeric material is placed on the first and the groups that are reactive with it are reacted with it as it cures.

Abstract: An elastomeric or rigid polymeric material, such as a propellant, is strongly bonded to an incompatible material, such as a silicon rubber liner, when a long chain polymer which is insoluble in and unreactive with the liner but has groups reactive with the propellant is added to the liquid or uncured liner. As the liner cures, the polymer chain migrates to the surface. Upon laying the propellant on the surface and curing the propellant, the propellant is cross-linked to the long chain polymer, which is entangled in the rubber liner.

Abstract: 1. A high density solid propellant composition comprising zirconium hydri ammonium perchlorate and a copolymer of vinylidene fluoride and perfluoropropylene.

Abstract: An inhibitor for double-base propellant consisting essentially of a layer Saran or polystyrene bonded to the propellant grain by means of a block copolymer containing vinyl chloride-vinylidene chloride blocks or polystyrene blocks and polyurethane blocks.

Abstract: A technique for improving the tensile strength of extruded fibers by incorating Teflon into hydrocarbon polymers. These polymeric compositions have extensive application in improving the physical behavior, reliability, and long term storage stability of extruded propellants, pyrotechnics and explosives.