Abstract: A multicolored foam product and a method for the preparation thereof. Heat-plastified foamable gel of a thermoplastic resin or resins containing blowing agents are combined with different coloring materials added sequentially and extruded through an orifice of a die which is extended in length to facilitate laminar flow in the resin. This resin is expanded to form a multicolored layered foam product, such as multicolored foam planking, in a single extrusion. Multicolored foam planking produced is suitable for use as the body material for surfboards, body boards, and other recreational products.
November 10, 1987
Date of Patent:
June 6, 1989
Packaging Industries Group, Inc.
John D. Bambara, Charles E. Flathers, Jr., Dennis A. Knaus, Gregory G. Palmieri
Abstract: The invention relates to a process of making articles of foamed polymethyl methacrylate (PMMA). In a first process stage a mixture comprising monomeric methyl methacrylate, plasticizer, preferably liquid foaming agent and catalyst is polymerized by heating and/or irradiation to form a foaming agent-containing solid body. In the second process stage this body is foamed by heating to the softening temperature of the plastic material. Either of these stages may also be performed continuously. The final product is clear-transparent and has large closed cells, a smooth surface, is light- and weather-resistant, readily workable, has good thermal insulation properties also in combination with plastics or glass coatings and may be used in a variety of applications, especially as a transparent insulating slab or plate.
June 8, 1982
Date of Patent:
July 23, 1985
August Hohnholz KG, Imchemie Kunststoff GmbH, Bernd Melchior
Abstract: Flexibilized, rigid plastic foam sheets with improved properties particularly desirable for low temperature and cryogenic insulation can be prepared by mechanical compression of freshly expanded closed-cell thermoplastic foams. Thus an extruded foam sheet having a density of 20-100 kg/m.sup.3, a y-axial size size of 0.05 to 1.00 mm and a Y-axial compressive strength of at least 1.8 kg/cm.sup.2 is flexibilized with 0.25 to 240 hours of expansion to give a flexibilized foam with improved elongation, workability, crack resistance and water vapor barrier properties.
Abstract: Rigid plastic foam is flexibilized in an apparatus utilizing four sets of foam gripping belts. A first and second set of opposed belts traveling at a given speed forward the foam into the apparatus to a second and third set of opposed belts traveling at a slower speed than the first and second set of belts. The first and third and the second and fourth sets of belts are interdigitated in a region of foam crush.
Abstract: A process for the continuous foaming of plastics, especially polyurethane, of the type in which the foaming space is delimited by flexible material bands which are fed together with the bun of foamed material being formed. As flexible material for these bands a composite web is used which comprises a support paper band and a thin impermeable band of plastics, preferably polyethylene having a thickness from 5 to 40 microns. The two bands of which the flexible is composed have a reduced adhesion to one another. The paper band is then detached from the bun of foamed material by disengaging it from the band of plastics which is left permanently adherent to the foamed material or is detached from this latter in an operation subsequent to the detachment of the paper band. In this way, losses of material are avoided, and the paper of the paper bands can be recovered.
Abstract: The disclosure relates to a process and device for the production of moldings from foamed thermoplastic plastic, e.g., polystyrol, in a mold, the mold wall enclosing a mold cavity, into which a filling injector discharges, and which is surrounded by an agent chamber and in which there runs an agent channel which is formed by drillings which are sealed at their ends against the outside and the agent chest by means of seals, and are connected to the mold cavity through nozzles. The drillings of the agent channel preferably run in ribs of the mold wall. The agent chest and the agent channel are connected through time-overlapping-controlled valves to an agent supply and removal system for the heating, cooling, inflation, curing, ejection of the mold walls and the molding respectively. A fast cycle sequence is achieved with a small consumption of energy and a high molding quality.
Abstract: A method of forming a synthetic article by open forming techniques by providing a fluid composition containing a predominant quantity of synthetic resin and having a capability for delayed, substantial gas evolution. To produce reinforced articles, the composition is applied to the reinforcement at a temperature below a predetermined gas evolution temperature and is subjected to fluid spreading conditions to thoroughly wet the elements of reinforcement. Subsequently, the fluid composition reaches the predetermined temperature, the resultant gas evolution effectively expands the composition while it remains in thorough wetting contact with the reinforcement elements, and the resin then solidifies and cures to produce an intimately reinforced, expanded article. In important embodiments the preponderant gas evolution results from the reaction of an organic hydroperoxide with an isocyanate in the presence of a surfactant.
Abstract: A railroad tank car includes a tank body and means for applying generally uniform heat to the lower portion of the body. There are a plurality of spaced generally semicircular rings attached to the body with each pair of adjacent rings defining a heat chamber which extends laterally about the lower portion of the tank body. There are longitudinal channels having ports which open into each of the heat chambers. There is a cover for the tank which includes a longitudinally extending generally semicircular metal jacket. A layer of insulation is positioned about the jacket and a layer of plastic foam overlies and adheres to the insulation. The structure is completed by a plastic exterior coat, preferably fiberglass, which overlies and adheres to the plastic foam.
Abstract: A porous membrane of an aromatic polyimide having an enhanced permeability of a gas or liquid is produced by a process comprising the steps of(1) preparing a dope solution of 3 to 30% by weight of an aromatic polyimide in a mixed solvent of (A) 100 parts by weight of a base solvent capable of dissolving 5% by weight or more of the polymeric acid and of evaporating at 30.degree. C. to 400.degree. C. and (B) 5 to 150 parts by weight of an additional liquid not capable of dissolving 3% by weight or more of the polyamic acid and capable of evaporating at a smaller evaporating rate than that of the base solvent at the above-mentioned evaporating temperature;(2) forming a thin layer of the dope solution at 0.degree. C. to 120.degree. C.; and(3) heating the dope solution layer at 30.degree. C. to 400.degree. C. so as to evaporate off the mixed solvent and to convert the polyamic acid to the corresponding polyimide.
Abstract: Microcellular foam materials having void fractions of about 5 to 30 percent and uniform void sizes on the order of 2 to 25 microns are produced by pre-saturating the material to be processed with a uniform concentration of a gas while controlling temperature and pressure to avoid cell nucleation. Processing is also done under pressure to avoid nucleation. After processing, pressure is released and cell nucleation occurs at or near the glass transition temperature of the material; it is then cooled quickly to preserve the microcellular structure.
July 30, 1982
Date of Patent:
September 25, 1984
Massachusetts Institute of Technology
Jane E. Martini-Vvedensky, Nam P. Suh, Francis A. Waldman
Abstract: A simplified method of manufacturing a silicon elastomeric foam comprises mechanically generating a stable froth of an aqueous silicone emulsion, while adding surfactant and thickener, then removing the water from the stable froth. The emulsion consists essentially of anionically stabilized hydroxyl endblocked polydiorganosiloxane, colloidal silica, an organic tin compound, and water, the emulsion having a pH in the range of 9 to 11.5 inclusive. The dried foam is an elastomeric, cellular structure possessing typical silicone elastomer heat stability.
Abstract: Method and apparatus for injection molding plastic articles having solid exterior surfaces and porous interior cores wherein a molten mixture of a chemically reactive foaming agent and a thermoplastic resin is injected into a mold so as to fill the mold cavity with unfoamed resin and form an outer solid skin on the molded article. Immediately prior to injection, an activator additive is introduced into the mixture, the additive reacting chemically with the foaming agent after a time delay of no more than a few seconds to provide for cellular expansion within the core of the molded article. The result is a molded body with a solid unfoamed skin which accurately relicates the surface of the mold and a cellular inner core.
Abstract: A method and apparatus for continually metering a gaseous blowing agent in an accurate and precise manner into a molten resin charge, such as polystyrene. This is accomplished by a free piston-cylinder combination which is actuated by the gas blowing agent and which continually meters discrete uniform volumetric charges of the gaseous agent into the molten resin. The blowing agent is uniformly distributed throughout the resin charge and extruded into a region of lower pressure to yield a foamed structure.
Abstract: Hot runner injection molding apparatus for coinjecting two thermoplastic materials sequentially through separate channels to form at least a two-layer sandwich material is provided. There is a valve means for instantaneously switching the flow of thermoplastic material from one channel to the other channel, the valve means preferably comprising a shuttle ball member.
Abstract: An extruder for delivering foamed glue from a foamer selectively to a plurality of spaced apart outlet orifices for extrusion onto a substrate surface and to bypass passageways for diverting the foamed glue to a defoamer for subsequent return to the foamer, is formed of three elongated flat blocks secured together releasably in face-abutting relationship. The surfaces of the outer, inlet and bypass blocks facing the center coupling block are recessed to provide a plurality of passageways all of which extend substantially equal distances from inlet and bypass ports in the inlet and bypass blocks, respectively, to a plurality of coupling ports in the coupling block. An air pressure operated selector valve in the bypass block is operable to communicate the coupling ports selectively with the bypass passageways for bypassing foamed glue to the defoamer and with the outlet orifices for extruding foamed onto a substrate surface.
September 17, 1982
Date of Patent:
September 11, 1984
Pacific Adhesives Company, Inc.
Edward J. Whittington, Boyd H. Hansen, Charles N. Cone
Abstract: The invention relates to apparatus for moulding a tire for a wheel rim by means of a mould having mould parts, said mould parts being movable between a closed working position in which they enclose a mould cavity with the shape of the tire and an open position in which said mould parts are spaced apart, wherein in the open position of the mould parts a hollow tire core is positioned in the mould cavity while being receivable with respect to said parts, wherein the mould parts are moved into the working position, in which a residual cavity not occupied by the tire core is left free in the mould cavity, said mould defining the residual cavity being adapted to receive synthetic resin foam for moulding a tire body. Preferably the tire core is arranged on the wheel rim before being positioned with respect to the mould parts.
Abstract: The invention is a method for making reaction injection molded polyurethane of improved properties and decreased catalyst usage. The product is formulated by placing the tin catalyst in the A-component (isocyanate component) rather than in the B-component (polyol side). Reaction injection molded elastomers are useful as molded articles of commerce including, but not limited to, vehicle body parts.
Abstract: Disclosed is a process for extruding thermoplastic resinous compositions, comprising the steps of heat plastifying the resinous composition in an extruder; cooling the heat plastified resinous composition exiting from the extruder to a uniform temperature desired for extrusion through an extrusion die, including conveying the resinous composition through at least one enclosed flow path in a cooling device, circulating a cooling medium about the entire circumference of each of the resin flow paths and controlling by the means of orifices the flow of thermoplastic at the inlet and the outlet of the cooling device across substantially the entire cross-section of each of the resin flow paths; and, extruding the cooled thermoplastic resinous composition through an extrusion die downstream of the cooling device.
Abstract: A foam extrusion apparatus and method in which extrudate is extruded into a sealed chamber which may be subjected to pressure variation such as a vacuum with the controlled shaping of the plastic being obtained by power driven rolls within the chamber downstream of the die. Because of the harsh environmental conditions within the chamber it is desirable that the shaping or forming rolls be driven by an externally powered source which will therefore be not subject to the pressure, vacuum, or other deliterious conditions found within the chamber. Moreover, because of the external position of the drive with regard to the chamber, the entire system need not then be shut down in order to open the chamber and make the required adjustments or repairs. The chamber is preferably the upper end of a barometric leg into which the extrudate passes. The upper end of the chamber is closed by one or more bulkheads which are movable toward and away from the upper end of the chamber.
Abstract: The invention relates to a process for the preparation of polyurethane or polyurethane-polyurea molded parts by reacting organic polyisocyanates, polyols and chain extenders in the presence of monocyclic amidines having the formula ##STR1## as catalyst or catalyst mixtures of monocyclic amidines having the formula (I) and (a) tertiary amines, (b) metal salts having the formula Me X.sub.n Y.sub.m (II), and/or (c) optionally-substituted aliphatic carboxylic acids. R.sup.1 and R.sup.2, Me, X, Y, n, and m are defined herein.