Abstract: Very desirable polyfunctional lithium containing polymerization initiators are prepared by reacting an adduct of an organo lithium compound and styrene with an organic compound containing at least two 1,1-diphenylethylene groups in the proportion of about two moles of the adduct to one mole of the organic compound. A difunctional lithium initiator is prepared thereby. The difunctional initiator may be reacted with styrene and subsequently an additional quantity of the diphenylethylene compound which in turn is reacted with the styrene-organo lithium adduct to form a trifunctional initiator. The process can be repeated to obtain an initiator having any desired degree of lithium functionality. Such initiators can be prepared in the absence of polar solvents and are very desirable for the polymerization of dienes such as butadiene to a desirable 1,4 configuration and preparation of block copolymers.
Abstract: Styrene and acrylic acid or methacrylic acid copolymers can be devolatilized at a temperature above 200.degree. C. and below the decomposition temperature of the copolymer under vacuum in the presence of a monohydric compound such as alcohol or water without significant increase in molecular weight or the formation of undesirable and insoluble gels.
Abstract: Open top tanks or ponds are provided with a thermally insulating floating cover which comprises a plurality of individual generally flat polygonal plates floating in edge-to-edge relationship. Each of the plates has at least one peripherally disposed downwardly projecting flange and means to vent gases from beneath the plate-like element.
Abstract: An improved flat-faced die face cutter is provided which permits flushing of the face with water with minimal chilling of the die. A spindle is provided which minimizes thermal effects on knife die face-positioning.
Abstract: Organic peroxide compositions suitable for free radical polymerization, the compositions comprising a mixture of a shock-sensitive peroxide and a diluent, the diluent being a monomeric material containing olefinic unsaturation which does not readily homopolymerize.
Abstract: Improved welds for thermoplastic foam insulation spirally deposited about a structure are obtained employing a thin, resistance heated welding blade which beneficially is positioned by means of a four-bar linkage connecting the blade to the blade support.
Abstract: Stable medium density large cell size styrene polymer foam is extruded in large sections employing as blowing agents: chlorofluoromethane, bromochlorodifluoromethane alone or in admixture with minor quantities of other halogen containing carbon compounds to provide machinable foams of good dimensional stability.
Type:
Grant
Filed:
November 2, 1976
Date of Patent:
April 18, 1978
Assignee:
The Dow Chemical Company
Inventors:
Kyung W. Suh, Graydon Wayne Killingbeck
Abstract: Curved sandwich panels having a plastic foam core are prepared by providing a flexibilized foam core, laminating inner and outer skins to the core. The outer skin is laminated to the core at locations other than where the panel will be curved, bending the panel to the desired shape and laminating the outer layer to the core.
Abstract: Isotactic polystyrene is heat fabricated in admixture with minor proportions of melamine, thymine, 2-hydroxybenzimidazole, oxamide and numerous other compounds to provide improved crystallization rates.
Abstract: Vinylidene chloride microspheres are polymerized in relatively large vessels with a relatively reduced peak exotherm employing a small quantity of a comonomer such as methacrylonitrile, methylmethacrylate, sytrene or butadiene which has a higher copolymerization reactivity with respect to acrylonitrile and a lower propagation rate constant.
Abstract: Vessel insulation is displaced from the adjacent surface of the vessel by fluid pressure and additional insulating material interposed between the insulation and the vessel.
Abstract: Loose fill foam plastic packing is prepared by extruding an expandable plastic composition to form an unfoamed or unexpanded strand which is subsequently cut into short lengths and foamed, the improvement which comprises extruding the strand through a generally helical passageway. The strand on foaming has a generally helical configuration.
Abstract: An improved cushioning element is provided which is prepared from a synthetic resinous cellular resilient body. A plurality of intersecting grooves are formed in the surface of the cushioning element thereby providing a body-supporting surface of a plurality of spaced-apart bosses generally independently deflectable and recoverable.
Abstract: Improved monovinyl aromatic monomer-acrylonitrile copolymers are prepared by polymerizing at temperatures above 80.degree. C in the presence of certain free radical initiators, the resultant polymers are prepared at high rates of conversion, have relatively high heat distortion temperatures, have a low oligomer content and generate relatively little additional acrylonitrile under fabrication conditions.
Abstract: Cured phenolic resole bodies including foams which are generally non-corrosive are prepared by including in the curable mixture an inorganic alkali-containing particulate solid such as certain glasses.
Abstract: Efficient heat sealing, particularly of thicker and/or heat shrinkable plastic materials, is obtained using a fluid heated and cooled heat-sealing member having a body of a material of low thermal conductivity and a strip of material of high thermal conductivity communicating with a heat exchange fluid passage therein.
Abstract: Compressible particulate sorbing or filtering media are contained in a filter cartridge comprising a split frame having peripherally disposed inwardly facing clamping ridges. Each portion of the cartridge has a foraminous face through which a fluid may pass within the frame and contained by the foraminous facings is a flexible foraminous member containing the parting sorbent in partially compressed form.
Abstract: Di-t-butylperoxy ketals are prepared from t-butyl hydroperoxide and the appropriate ketone in the presence of from 1 to 10 times the weight of ketone of ethylbenzene employing an acidic catalyst. Water is removed by azeotropic distillation with ethylbenzene and excess t-butyl hydroperoxide is subsequently removed by azeotropic distillation of additional ethylbenzene to provide a solution of the di-t-butylperoxide ketal in ethylbenzene which is particularly desirable as an initiator for styrene polymerization.
Abstract: A centrifugal extruder is provided with a friction generating element within a hollow rotor of the extruder. The material to be extruded is heated by shear generated by differential rotation between the extruder rotor and a shear generating element. Heat plastification is obtained adjacent the periphery of the rotor and a very short heat history is added to material treated in the apparatus.
Abstract: Large vessels such as tanks and the like are insulated by means of a spiral generation process thereby providing rapid application of the insulation with minimal labor. The process is particularly suited for operation in confined quarters.