Abstract: A method and apparatus for extruding a multi-layer plastic pipe are provided wherein a second liquified plastic is injected into and through a prow and, subsequently, into a radial flow conduit of a die assembly in which a first liquified plastic flows through the radial flow conduit. Subsequently, the first and second liquified plastic are introduced into and through an annular flow conduit and a third liquified plastic is injected into the annular flow conduit of the die assembly. Wherein within the die assembly the first liquified plastic forms a first layer, the second liquified plastic forms a second layer inside the first layer and the third liquified plastic forms a third layer outside the first layer. Additionally, a multi-layered plastic pipe which can be produced by the inventive die assembly is provided. The multi-layered plastic pipe has an ultraviolet light-protective outer layer and a light-reflecting inner layer.

Abstract: A durable reusable polymeric mold for casting a microstructure sheet having an array of prism elements and a method for forming the microstructure sheet are disclosed. A polymeric mold has a facet side and a base side including an array of prism elements upon which an radiation cured sheet can be formed. A protective surface layer can be formed on the facet side of the polymeric mold. The protective surface layer is sufficiently opaque to radiation to protect the polymeric mold from damage when the curable sheet is formed and is sufficiently bonded to the polymeric mold to allow the cured sheet to be removed from the protective surface layer while not substantially removing the protective surface layer from the polymeric mold. The microstructure sheet can be used as a retroreflective structure.

Abstract: A 3-dimensional opto-electronic system employs an optical communications channel between spaced circuit substrates. The beam from an in-line laser on one substrate is deflected by a turning mirror that is monolithically integrated on the substrate along with the laser and its associated electronic circuitry, and directed to an optical detector on another substrate. The deflection is accomplished with a turning mirror that is specially fabricated with a focused ion beam (FIB) so that it focuses or collimates as well as deflects the laser beam onto the photodetector. The mirror is initially formed with a flat surface, and is thereafter processed with the FIB to produce focusing curvatures in both x and y directions. The mirror is preferably spaced away from the laser, and is illuminated over substantially the full laser height to maximize its focal length for a given reflected spot size.

Abstract: A first binary diffractive optical element has a multi-level surface relief phase grating structure on a substrate. The first binary diffractive optical element can be divided into regions commensurate with resolution requirements of the intended optical application and the diffraction efficiency of each region of the binary diffractive optical element measured. The lowest measured diffraction efficiency for a region of the first binary diffractive optical element will be taken as the reference efficiency. The diffraction efficiencies for all the regions of the binary diffractive optical element will be reduced region by region to the common value of the lowest measured diffraction efficiency by introducing compensating diffractive losses to the regions by a second, corrector binary diffractive optical element which has a binary surface relief phase grating structure on a substrate.

Abstract: In a process and apparatus for the overall machining of a ceramic tooth restoration and producing of appropriate sonotrode crowns, these sonotrode crowns act on a workpiece one after the other, however from the same direction in space and are activated by the same ultrasonic transmitter. For the production of said sonotrode crowns, a geometrical model corresponding to the ultrasonic machining apparatus is used.

Abstract: A method of increasing retroreflective brightness in a retroreflective sheet material. The retroreflective sheet material has a multitude of prism-like reflective elements imbedded in a transparent polymer plastic top film and glued by a grid of adhesive to a backing sheet. The method includes the step of heating the retroreflective sheet material until bubbles form in the transparent polymer plastic top film containing the prism-like reflective elements. The bubbles are confined by the grid. The bubbles serve as miniature magnifying lenses which increase retroreflective brightness and increase the exposure area thereby providing a wider observation angle.

Abstract: A method for forming a weatherstrip includes extruding a compound formed of 1-10 weight of polyglycidyl methacrylate having an epoxy group in the molecular structure thereof added per 100 parts of a rubber compound formed of SBR/EPDM. As the compound is extruded from the extruder, a urethane coating material is supplied to a nozzle to accomplish coating of an article concurrently with forming thereof. The extruded article is then vulcanized to assure good sealability.

Abstract: A process for the production of a ceramic prosthesis by forming a blank from a mixture of zirconium oxide and hafnium oxide of between 94.8% and 95.3% by weight, yttrium oxide of between 4% and 5.2% by weight, and any further oxide as a balance of less than 1% by weight, with a monoclinic proportion of below 5% by volume. The blank is put into the shape of the required prosthesis by means of a rotating tool of metallically bound diamond grains, using specific operating parameters for the tool.

Abstract: The present invention provides a novel dental composition and a method of making shaped dental articles therefrom via photoiniferter polymerization. The dental composition comprises acrylic photoiniferter block polymer, a monomer charge comprising free radically polymerizable acrylic monomer, and a filler and optionally includes pigments, sensitizers, medicaments, stabilizers, accelerators, etc. The dental composition is alternately exposed to a source of radiant energy and shaped in a desired manner in order to form a partially cured dental article. The partially cured dental article is then cured by a final exposure to the radiant energy source, providing a final cured article. The resultant reinforced acrylic copolymer system provides a shaped dental article which can be a denture base, a denture liner or a restorative.

Abstract: A method of making a microlens array where the microlenses have focal lengths which vary as a function of their geometric position in the array. The focal lengths of the microlenses at the center of the array are shorter than the microlenses at the periphery.

Abstract: The present invention discloses the construction and manufacturing method of a turning mirror which has a single face or multiple face reflector mirror for scanning laser light in a laser beam printer and the like. The disclosed construction and manufacturing method achieve a low-cost and high-accuracy turning mirror. Photo-setting resin is coated onto the surface of a base mount having a rotating shaft at its center. The surface of the base serves as a substrate for reflector mirror. A glass plate having a good flatness is placed into contact with the resin coating layer. Resin setting light is operated to irradiate the resin coating layer with the peripheral side fringe of the resin coating layer partially or entirely open in order to set the resin coating layer. The glass plate is then separated from the resin coating layer, allowing the flatness of the glass plate to be transferred to the resin coating layer. The turning mirror is then fabricated by attaching a metallic film onto the resin coating layer.

Abstract: A lamp assembly having a plastic housing and a plastic lens is molded in a rotary transfer molding machine having upper and lower mateable housing dies and upper and lower mateable lens dies in which the housing and the lens are molded simultaneously. The machine is then indexed so that the upper housing die with the molded housing retained in it is mated with the lower lens die with the molded lens retained in it. These two dies are configured so that an annular seal bead cavity is formed at an interface of the dies. A seal bead is then molded to join the molded housing to the molded lens to provide the lamp assembly. The machine is then indexed again so that the upper housing die with the lamp assembly retained in it is mated with an overlay die and a decorative overlay is molded on the peripheral margin of the lens.

Abstract: The present invention relates to a transparent material based on addition-crosslinking polysiloxanes, which is used as occlusal print for molding side teeth composites.

Abstract: Methods and apparatus for generating, and then precisely controlling, layer thickness gradients in multilayered polymeric reflective bodies are provided. The creation of such gradients is useful in tailoring multilayer bodies to reflect and/or transmit desired wavelengths of light. Both thermal and mechanical methods, as well as combinations thereof, are used.

Abstract: Improved optical disks for information storage and holographic imaging, and optical lenses and reflective optical elements are among the difficult-to-mold thermoplastic products which require precision replication of the molding surfaces, in micro detail. By heating (with circulating heat transfer fluids supplied by a hot side reservoir) these mold surfaces to a temperature setpoint sufficiently high to retard solidification and premature viscoelastic skinning of the molten thermoplastic injected into the mold cavity, superior quality molded surfaces can be formed by the plastic, which is then rapidly cooled to solidification (by circulating heat transfer fluids supplied from a cold side reservoir).

Abstract: A reflection type projection screen is constituted as follows. Provided in order on a light absorbing layer 5, which is a dark plastic sheet or a solid print of a dark ink, are a fibrous sheet 4 of glass fibers, a white, opaque base material sheet 3made with a plastic sheet, and a light diffusing layer 2 of a translucent plastic into which a lustrous pigment or calcite powder is incorporated. An emboss 9 is formed on the outer surface of the light diffusing layer 1. It is preferable that a reflection layer 2 printed with an ink containing a lustrous pigment or calcite powder is provided below the light diffusing layer 1. Light absorbing stripes 11 are provided each at a position corresponding to a concave portion 9a of the emboss 9 on the surface of the base material sheet 3 adjoining the light diffusing layer 1. A production process and a production apparatus of a reflection type screen, which can efficiently produce reflection type screens with the emboss are also disclosed.

Abstract: A trimodal method of curing dental composite restorative materials involves the use of visible light illumination for the initial curing of the composite resin and a combination of dry heat and vacuum for the complete cure of the composite restorative materials. More specifically, the method for preparing dental restorative materials includes the steps of forming a dental restoration from a composite resin of a type conventionally employed in the dental profession, in which the composite resin includes a photosensitizing system for initiating polymerization of the composite resin upon exposure to visible light, an initiator for initiating polymerization upon application of heat and at least one filler; exposing the thus prepared restoration to a source of visible light to at least partially cure said composite resin and then subjecting the thus prepared restoration to a combination of heat and vacuum to complete polymerization of said complete resin.

Abstract: A process for making artificial porcelain teeth or laboratory fabricated dental crowns includes casting or molding a plurality of tooth-shaped unfired shells from ceramic powder and a resin, acrylic, wax or starch in liquid form and molded and hardened into shapes of predetermined tooth contours. These dried powder like, thin and highly characterized outside shells of a general tooth shape are then merged into a full porcelain powder buildup of the tooth shape by using conventional porcelain powders mixed into a paste, conventionally, as a filling medium completing the buildup of tooth or crown form. This form is then placed into a furnace and heated to purge undesired resin, acrylic, wax or starch and other extraneous material, and then it is baked conventionally to further purge same and obtain an artificial tooth or crown in the most desirable form possible for the technician who then finalizes the contour by grinding and polishing or glazing same conventionally.

Abstract: Oxide-free metallic, alloy or intermetallic compound formed by coating a powder of at least one member selected from the group consisting of elemental metallic, alloy and intermetallic compound with an oxide-replacing metal. The oxide-free compound may be compacted without the addition of a liquid sintering agent and at temperatures below the melting point of the compound, under sufficient pressure to form a uniform, consolidated intermetallic body.

Abstract: A method for the production of a lamellar reflective polymeric body is provided and includes the steps of providing a first stream of a first heat plastified polymeric material and a second stream of a second heat plastified polymeric material, and encapsulating discrete portions of the first polymeric material in the second polymeric material by coextruding the polymeric materials to form a plurality of ribbon-like layers of the first polymeric material within a matrix of the second polymeric material to form the reflective polymeric body. The layers of the first polymeric material are arranged to have their major interfaces aligned substantially parallel to the major surfaces of the body such that at least 30% of light incident on the body is reflected. The ribbon-like layers may be further divided into a series of platelet-like layers to produce layers which are discontinuous in all major planar dimensions by passing the ribbon-like layers through a reciprocating feed plate or valve.

Abstract: A method of making a microlens array and mold, and the articles made therefrom. The method involves forming a plurality of adjacent receptacles on a surface and partially filling the receptacles with a hardenable liquid, thereby forming a meniscus in each receptacle. A lens material can then be applied to the menisci, thereby forming an array of generally spherical microlenses. In one embodiment, the perimeters of the microlenses are modified rectangles in that each edge of the lens is a symmetrical elliptical arc, the ends of which terminate at the corners of the rectangle, and the middle of which curves toward the center of the rectangle.

Abstract: A dental refractory model material comprises as powdery components 5 to 20% by weight of a soluble phosphate, 5 to 20% by weight of magnesium oxide and 10 to 50% by weight of at least one selected from the group of alumina, zirconia, fused quartz, mullite, spinel and cordierite with the balance being crystalline quartz and crystobalite. The refractory model material also includes a liquid component such as a colloidal silica dispersion.

Abstract: An improved lamp assembly for a motor vehicle and a method for molding same is provided in which a one-piece lamp having one or more colors or reflective means integrated in a single lens panel and frame is molded in a single plastic injection process. In the process, one or more colored or reflective elements are placed between two mold segments, the mold segments are closed, and a plastic is injected into the mold cavity in bonding securement of the colored or reflective elements.

Abstract: A plurality of mold members are disposed on an index table to be intermittently rotatably driven. Energy sources for curing the activation energy curable resin at positions to which the mold members are intermittently moved, a first robot for supplying a molding parent material to the mold member, a second robot for taking out an optical element after molding from the mold member, and a third robot for supplying the activation energy curable resin before supplying the molding parent material to the mold member are disposed proximate to the index table. The operations of each robot are performed together at each moved position of the mold member.

Abstract: A light reflective body useful for a panel-type lighting or ornamental member with edge lighting is formed of a transparent inorganic or organic casted glass member, such as a transparent plate of polymethyl methacrylate which has foam layers unevenly dispersed in the inner or outer face of the member or plate. The organic casted glass member of the light reflective body is manufactured by (a) gelling organic glass beads and an organic glass monomer or prepolymer or a mixture of them and thereafter casting them with an organic glass monomer or prepolymer or a mixture of them in a framework; (b) spreading the foaming material on a ready-made organic glass plate and hardening it; or (c) tightly attaching an organic glass foam plate manufactured in advance to an organic glass plate. In accordance with the method (a) or (b), the foam layer is completely integral with the organic casted glass product. Method (c) can also be applied to an inorganic casted glass member.

Abstract: A flexible retroreflective sheet material is formed by adhering a first face of a first flexible synthetic resin sheet material to a synthetic resin second sheet material by a first adhesive which preferentially adheres to the second sheet material. On the second face of said first sheet material are thereafter formed closely spaced retroreflective microprisms having a height of 0.001-0.010 inches. A second adhesive is applied to the second face of said first sheet and firmly engages therewith. A flexible backing material is adhered to the second adhesive over the second face. Lastly, the second sheet material and first adhesive are stripped from the first sheet material to produce a firmly bonded flexible composite sheet material comprised of the adhesively bonded first sheet material and backing material. The retroreflective microprisms may be coated with a reflective metal deposit or surrounded by air to provide a retroreflective interface.

Abstract: The present invention relates to a process for producing dental working cast for use for preparing a crown or a denture of metal-bonded porcelein or of all ceramic in dental therapy, by preparing a removable positive model of tooth from impression, processing it into a model of the working cast and replicating the model using a suitable material chosen from resin, die material, refractory cast material and modified dental stone, to obtain the working cast.

Abstract: A plurality of binary diffractive optic lenses are formed in the surface of one substrate and a corresponding plurality of recesses are formed in the surface of another substrate. The binary diffractive optic lenses on one substrate are aligned with the recesses on the other substrate and the two substrates are bonded together. A plurality of individual binary diffractive optic lens cover assemblies are obtained by dicing the two bonded substrates.

Abstract: A crown and/or a replacement tooth and a method of in situ production thereof by grinding and shaping a tooth to form a prepared tooth; filling a transparent shell tooth form with a light setting resin; disposing the filled shell tooth form onto the prepared tooth; illuminating the filled transparent shell tooth form to set the light setting resin and bond the resin to the shell tooth form; and shaping and polishing the set resin in situ to form a crown. A set of shell tooth forms is provided which are formed from a light setting resin chemically compatible with the resin used to fill the form in order that bonding occurs therebetween. This feature enables the products of a replacement tooth formed in situ without the necessity of shell tooth form removal as heretofore required.

Abstract: A microstructure-bearing composite plastic article can be superior, both in microstructure and in physical properties, when it is a composite of a tough, flexible substrate, at a surface of which is microstructure formed of a cured oligomeric resin having hard segments and soft segments, which cured resin is substantially confined to the microstructure portion of the composite. Such a composite plastic article can be made by depositing an uncured oligomeric resin composition onto a master negative molding surface, filling the cavities by moving a bead of the composition between a substrate and the master, and curing the deposited composition by ultraviolet radiation while keeping the temperature during curing from rising not more than about 30.degree. C. above a typical use temperature of the finished composite plastic article.

Abstract: An optical information record carrier (optical disk, conventionally) has multiple reflective surfaces, each carrying separate information and each readable by an optical beam directed from the same side of the record carrier. The top most reflective surface reflects light of a first waveband and passes light of a second waveband. The next top most reflective layer reflects light within at least part of the second waveband. The record carrier is formed by producing a first reflective layer having a first pit pattern in the surface of a transparent substrate, pressing said first substrate/layer combination to a transparent stamper having a second pit pattern, with a radiation hardening liquid resin therebetween, irradiating the resin by applying radiation to said resin through said stamper, peeling off said stamper, applying a second reflective layer to said hardened resin surface opposite the surface in contact with said first reflective layer, and applying a protective layer to said second reflective layer.

Abstract: A method and apparatus to continuously harden articles made of visible light-curable resins, including continuously moving the articles to be hardened relative to a multiplicity of sources of visible light which are independently controllable to be able to vary the radiation to which the articles is exposed during its passage while independently controlling the temperature at which this takes place; and apparatus to accomplish this such that a large number of the objects to be irradiated passing through the hardening apparatus have the same exposure history to the visible light and to heating or cooling respectively. As the result, there is substantially no variation in the physical properties of these photo-polymerized products.

Abstract: A method to continuousky harden light-curable resins, by irradiating at least one shaped article made of a light-curable resin by continuously moving the article past a multiplicity of light sources while changing the flux of the irradiated light in multiple steps corresponding to the moving positions of the object and an apparatus to accomplish this method including means to continuously move the article relative to the multiple irradiation sources and means to adjust the flux density in multiple steps corresponding to the moving positions of the article. Specifically, the flux density of the light irradiated on the moving article is changed stepwide depending upon the position and the location of the article and the polymerization speed of the article and the hardening depth can be controlled in relation to its position and time.

Abstract: A cast mold and process for casting a substrate for an information recording medium has an uneven preformat pattern formed on the mold surface. The uneven preformat features a pattern corresponding to tracking grooves and information pits, each information pit portion has a size with a length b in the direction parallel to the pattern of the tracking groove of 2 to 15 .mu.m and a width a in the direction perpendicular thereto of 1 to 6 .mu.m and a height c of 300 to 3500 .ANG.. The pit pattern has a pitch which is 1.8-fold or more of pit length b.

Abstract: The part (3) is made, in a non-polymerized form, by juxtaposition of a major volume (4) at least equal to 80% of the total volume of the part (3) and of a complementary volume (5). First, the photopolymerization of the major volume (4) is carried out. Then, the photopolymerization of the complementary volume (5) is carried out, the major volume (4) and the complementary volume (5) being held in contact. The method applies particularly to restorative dentistry.

Abstract: Method for machining flat, circular disk-shaped recording media, for example, audio, video or ROM compact disks, for the purpose of improving their surface quality and their dimensional stability, employs a lathe having a driven lathe spindle (7), a vacuum chuck (8) for holding the recording medium or substrate (15, 15'. . . ) to be machined, and a carriage (9) for holding and guiding the cuting tool (5) magazine (14) hold the machined and unmachined substrates, there being further provided a robot (10) held on the base (2) or bed (4) of the lathe and having a gripper arm (11) with gripping tongs (12) movable in several planes which transport the substrates from one magazine (14) to the vacuum chuck (8) or from the vacuum chuck to the other magazine, the stacking axes (L) of the two magazines extending at an angle to the horizontal plane (E), and the magazines being maintained within the range of action of the gripper arm (11) with gripping tongs (12).

Abstract: A sheet of material for forming the screen is mounted on a cylindrical forming drum and is blow formed, by hot air under pressure, to provide a projection screen. The resulting screen is curved along the width thereof and curved along the length thereof, and is formed from a single, continuous, sheet of material so that the screen is a stand-alone screen.

Abstract: A method for fabricating in a mold a rotatable recording drum. Initially, the mold is rotated and a predetermined quantity of a flowable substance is poured into the mold cavity and is centrifugally flung against the mold wall to form a mold layer with a smooth inner surface. Next, a surface substance is poured into the mold cavity and is allowed to harden against the mold layer. A core outer layer substance is then poured into the mold cavity and allowed to harden against the surface substance, and rotation of the mold is stopped. The mold layer fluid is removed, and the cavity inside the outer layer is filled with a core inner layer substance which is allowed to harden before the drum core is removed from the mold cavity. Following removal of the core from the mold cavity, the hardened surface substance may be vacuum coated, and a protective overcoat applied to the core. The drum core and the surface substance can also be formed separately.

Abstract: A method of making a positive model of a tooth or gum involving the steps of pouring hardenable positive impression material into a negative impression of the tooth or gum comprising a curved, vinyl polysiloxane composition, and hardening the positive impression material, wherein the improvement involves applying finely divided palladium over at least part of the surface of the negative impression that will contact the positive impression material before pouring the hardenable positive impression material.

Abstract: A process to fabricate lightweigth ceramic mirrors, and in particular, silicon/silicon carbide mirrors, involves three chemical vapor deposition steps: one to produce the mirror faceplate, the second to form the lightweight backstructure which is deposited integral to the faceplate, and the third and final step which results in the deposition of a layer of optical grade material, for example, silicon, onto the front surface of the faceplate. The mirror figure and finish are fabricated into this latter material.

Abstract: A process for making optical mirrors which includes making a rough plaster casting to about the desired shape of the mirror, with the casting having a rough surface, and then applying successive thin layers of polyester resin to the surface of the rough casting to form a finished casting having a smooth coated surface suitable for use as an optical mirror.

Abstract: There is provided a mixture which preferably is a colloidal suspension of finely divided particles of a rare-earth oxide such as cerium oxide in a liquid. The liquid may be all water but also may include other materials such as acetic acid, 1,3-butanediol, methanol. The mixture is used as a wetting and suspending agent for opaque and build-up dental porcelains to primarily overcome the problem of discoloration of the porcelains when used with metal substrates made of dental alloys containing silver, and also to make the porcelains easier to handle and to work with.

Abstract: A cast mold and process for casting a substrate for an information recording medium has an uneven preformat pattern formed on the mold surface. The uneven preformat features a pattern corresponding to tracking grooves and information pits, each information pit portion has a size with a length b in the direction parallel to the pattern of the tracking groove of 2 to 15 .mu.m and a width a in the direction perpendicular thereto of 1 to 6 .mu.m and a height c of 300 to 3500 .ANG.. The pit pattern has a pitch which is 1.8-fold or more of pit length b.

Abstract: A novel method is disclosed for producing specular surfaces, composed of pure carbon, on carbon-carbon composites of arbitrary weave configuration. The method utilizes a thin sheet of fine grained polycrystalline graphite as a stress-isolating interlayer between the composite substrate and the specular surface layer. The interlayer is bonded to the carbon-carbon substrate with a high char yield carbonizable adhesive. An outer layer of glassy carbon is then applied using a high char yield resin solution or (lacquer). The resulting assembly is then carbonized to convert all uncarbonized polymer to carbon. The interlayer prevents the propagation of the substrate carbon-carbon composite's crack structure to the glossy carbonized polymer surface thus formed, resulting in a high degree of specularity and zero gas permeability.

Abstract: A lens array of rod lenses (16), to be used for reading image data in document copier, facsimile, printer, white board scanner, and so on, is made by injection molding of a transparent resin in an already made plastic lens-holding frame (3) having an array of through-holes (2) and gates (1) leading to respective through-holes (2) for injecting melted transparent resin therethrough, both ends of the through-holes having cores (6) and (7) with concave faces.

Abstract: A recording medium for optical high-density data storage and retrievel, comprising a flat transparent plastic substrate characterized by the following relationship between the refractive index (n.sub.z) in the direction perpendicular to the flat surfaces of the transparent substrate, and the refractive indexes (n.sub.x) and (n.sub.y) in the direction parallel to the flat surfaces of the transparent substrate:.vertline.n.sub.z -n.sub.x .vertline. smaller than 4.times.10.sup.-4 ; and.vertline.n.sub.z -n.sub.y .vertline. smaller than 4.times.10.sup.-4.The recording medium is produced by an injection molding process wherein the pressure on the molten resin filled into the molding cavity of a mold is decreased or increased, as appropritate, in order to maintain the desired differences between the refractive index n.sub.z in the direction perpendicular to the flat surfaces of the transparent substrate, and the refractives indexes (n.sub.x) and (n.sub.

Abstract: Thermoformable laminate films with a decorative feature include a polymer carrier film, a paint layer and an optional protective clearcoat and the clearcoat and paint layer have a preconfiguration which produces uniform decorative color appearances following deformation of the laminate by a thermoforming process. To accomplish such results, the laminated film has a carrier film prestretched to orient pigment flakes in the paint layer prior to molding, thereby to reduce strain levels required to mold the laminate with an acceptable surface appearance. The process of manufacture includes the steps of painting a polymeric support or carrier film and prestretching the painted carrier film to control the color hue appearance of the laminate as applied to an underlying relatively rigid substrate or body part.

Abstract: In a silicone impression and duplicating composition which undergoes crosslinking at ambient temperature by an addition reaction, comprising(a) an organopolysiloxane possessing two or more vinyl groups in the molecule,(b) optionally an organopolysiloxane without reactive groups,(c) an organopolysiloxane possessing two or more Si-H groups in the molecule,(d) a catalyst,(e) a filler and,(f) optionally an auxiliary and/or colorant, the improvement wherein polysiloxane components (a)-(c) contain not more than about 1.5% by weight of volatile oligomers, whereby the dimensional stability of impressions is improved.

Abstract: A casting mold for the production of muffles which serve for the conversion of wax models to metal, with the casting mold having a funnel shaper (1) which consists of a disk-shaped base plate (4), at the circumference of which a side wall (5) which stands vertical to the base plate (4) runs, and a cone (6) arranged in the center of the base plate (4), pipe-shaped, muffle ring (2) partially inserted into the funnel shaper (1), with the outside wall of the muffle ring (2) resting against the inside circumference of the side wall (1) of the funnel shaper (1), a cylindrical ring (7) which is inserted on the side of the muffle ring (2) which faces the funnel shaper (1) and the central opening (8) of which surrounds the cone (6), and a blind funnel (3) provided on the side of the muffle ring (2) opposite the funnel shaper (3), whose funnel tip faces towards the cone (6 ) of the funnel shaper (1).

Abstract: A method of making a positive model of a tooth or gum including the steps of pouring hardenable positive impression material into a negative impression of the tooth or gum comprising a cured, vinyl polysiloxane composition, and hardening the positive impression material, and further including applying finely divided palladium over at least part of the surface of the negative impression that will contact the positive impression material before pouring the hardenable positive impression material.