Abstract: An improved process for producing a linear polyester having a high degree of polymerization which comprises first preparing a prepolymer of polyester and then polycondensing the prepolymer. In the first step, a prepolymer having an intrinsic viscosity of at least 0.2 is prepared, and the subsequent polycondensation is carried out in the presence of an organic boron compound of the formula ##STR1## wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 represent an alkyl, aralkyl or aryl group having 6 to 20 carbon atoms, and M represents a monovalent metal. According to this method, the polycondensation can be performed at atmospheric pressure, and a substantially linear polyester having an intrinsic viscosity of at least 0.5 and superior thermal stability can be obtained rapidly.

Abstract: A process for incorporating CaF.sub.2 into polyamides is described. The process involves reacting a calcium salt with a fluoride salt in molten polyamide.

Abstract: A process for manufacturing petroleum resins for adhesive thermofusible compositions, having a softening point comprised between 60.degree. and 110.degree. C., a molecular weight comprised between 700 and 1,500 and a Gardner color index less than 9, consisting in polymerizing a C.sub.5 hydrocarbon distillation cut issuing from a steam cracking of naphtha or gas-oil and containing less than 5% isoprene and less than 1% cyclopentadiene, in the presence of a Friedel-Crafts catalyst.

Abstract: The invention relates to a method of manufacturing shaped articles from crystalline or quasi-crystalline acrylonitrile polymers and copolymers, said method consisting in cooling down a solution of said polymer or copolymer in a mixture containing from 50 to 99.5% by weight of a solvent and from 0.5 to 50% by weight of a precipitant to a temperature below the gelation point of the solution until the same gelatinizes, without changing its composition, to the desired shape, whereafter the solvent is removed from the shaped thermoreversible gel thus obtained at temperatures lower than the gelation point of the solution, preferably using a liquid precipitant of polyacrylonitrile miscible with the solvent. It is advantageous to remove the solvent at a temperature which is at least 10.degree. C. lower than the gelation temperature of the polymer solution used. The shaping can be carried out in any convenient way, e.g. using a stationary or rotating mold.

Abstract: This invention concerns a method for the removal and recovery of synthetic polymers from solvents using dropwise impingement of a solution of the polymer in a solvent upon a mobile capillary inactive liquid surface to volatilize and recover the solvent, leaving the previously dissolved synthetic polymer on the surface of the capillary inactive liquid. The solvent is recovered by condensation for reuse and the polymer is recovered from the surface of the liquid by mechanical means.

Abstract: The thermal and chemical stability of etherified acetal homopolymers is improved by heat-treating the latter in the molten state at a temperature of at least 180.degree. C., in the presence of a halide of an alkali or alkaline earth metal, until substantially complete degradation of the unstable polyoxymethylene chains.

Abstract: Dewatering aqueous polymer slurries containing polyvinylalcohol stabilizer by forming an insoluble organic destabilizer in situ from a soluble parent compound comprising ionizable groups. The slurry may then be filtered at 50.degree. C. or higher to yield a soft cake of beads essentially free of stabilizer.

Abstract: Isolating thermoplastic or thermoelastic polymers in the form of a powder of limited water and precipitant content and uniform grain size from their aqueous dispersions wherein(i) a polymer dispersion and a precipitant are intensively mixed at an uptake of mechanical energy of 0.2 to 0.6 KWh per m.sup.3 of dispersion thus causing high turbulence,(ii) the polymer is precipitated while in this state of high turbulence at a temperature below the sintering temperature of the polymer,(iii) the precipitated polymer particles are agglomerated and hardened while still in contact with the aqueous liquor either in one or in several stages, and(iv) the aqueous liquor and agglomerated polymer particles are separated from one another.

Abstract: Ethylene is polymerized, in the presence of hydrogen, at a temperature of 180.degree. to 340.degree. C and a pressure of 200 2,500 bars with a Ziegler catalyst in a stirred reactor having at least one first reaction zone and at least one second reaction zone. The reaction mixture is fed to a separator at a pressure of 80 to 400 bars. The improvement results from partially liquifying at least a part of the gas coming from the separator at a temperature of -50.degree. to +20.degree. C, releasing the pressure to a value of 10 to 60 bars, separating the partially liquified gas into a gas phase and a liquid phase, and recycling the gas phase to the second reaction zone and the liquid phase to the first reaction zone. The resulting polymer has a low melt index, a high polydispersity index, and superior physical properties compared to polymers prepared by conventional processes.

Abstract: A polymer latex is coagulated by passing the polymer latex and a coagulant through a screw-type extruder in which the latex and coagulant are mixed and mechanically worked under pressure by a rotating interrupted worm flight in cooperation with a plurality of stationary breaker members. At the downstream end of the extruder, the coagulated polymer is compacted and extruded. The extruded polymer is characterized by relatively low moisture content, and the excess process liquid which drains from the compacted polymer is relatively free of uncoagulated polymer.

Abstract: An aqueous gel of a water-soluble polymer containing units of a quaternary ammonium salt of an alkylacrylate or a methacrylate is dehydrated by adding at least one salt of a divalent metal and a strong acid to said gel and then dehydrating said gel.

Abstract: Improved processes for the dehydrohalogenation of halogenated butyl rubber in order to prepare a butyl rubber having randomly distributed sites of conjugated unsaturation are disclosed. Such processes, which include the contacting of a solution of halogenated butyl rubber with a soluble metal carboxylate, a soluble carboxylic acid, and an oxide or hydroxide of a metal selected from Groups Ia and IIa of the Periodic Table, are carried out in a reaction zone which is maintained substantially free of free water vapor. Preferably, excess amounts of hydrophilic reagents are added to the reaction zone or in the alternative the reaction zone is purged with a drying gas.

Abstract: Spherical polyolefin (or modified polyolefin) powders having high bulk density, narrow particle size distribution and good powder flowability are prepared by cooling a polyolefin solution comprising a solvent and nonsolvent for the polyolefin and containing a small amount of an inorganic compound and, if desired, water. The polyolefin powders are suitable for powder coating. Suitable solvents are hydrocarbons, such as hexane, heptane, etc., and a mixture of hydrocarbon and nonsolvent for polyolefin such as methyl alcohol, ethyl alcohol, isopropyl alcohol, etc. The ratio of a hydrocarbon/nonsolvent is 95/5 - 30/70, preferably 90/10 - 50/50. Suitable inorganic compounds are phosphoric acid, sulfuric acid, sulfurous acid, hydrochloric acid, sodium hydroxide, potassium hydroxide, ammonium hydroxide, inorganic salts thereof, etc. and the most preferable inorganic compound is phosphoric acid.

Abstract: Preparation of free-flowing granules of practically uniform composition and particle size consisting essentially of poly-N-vinylpyrrolidone and iodide (I.sup.-) by combining with uniform thorough mixingA. a solution and/or colloidal suspension of a substance releasing iodide ions in a first solvent or solvent mixture, as well asB. a solution and/or colloidal solution and/or suspension of PVP in a second solvent or solvent mixture which possesses a surface tension different from that of the first solvent or solvent mixture, and in which PVP is at least partially soluble or wettable, and in which the substance releasing iodide ions, contained in the first solvent or solvent mixture, is insoluble or only slightly soluble;And separating and drying the granules formed.

Abstract: Granular rubber is prepared by allowing a latex mixture of a rubber latex and an aqueous solution of a high molecular weight polyanion containing carboxylate groups and/or hydroxyl groups to fall freely into an aqueous solution of an alkaline earth metal salt and separating the granular rubber which forms.

Abstract: A process for producing powder paint particles, particularly metal-flake containing powder paint particles, which comprises contacting the exposed surface of an aqueous saline solution in continuous movement through a spreading and extraction zone into a collection zone with a liquid dispersion of said organic paint binder, said metal flakes and an organic solvent miscible with said saline solution wherein said liquid dispersion floats on said surface for a time sufficient to admit of its spreading on said surface extraction of organic solvent from the floating liquid paint dispersion into said saline solution, and solidification of said paint binder on said surface into plate-like solids containing metal flakes with said spreading and extraction zone, and movement of said saline solution and floating plate-like solids into said collection zone wherein said plate-like solids are broken into smaller particles and recovered.

Abstract: A method for enhancing the solubility of substantially dry polymers and copolymers of water-soluble ethylenic-unsaturated monomers.

Abstract: Synthetic styrene-conjugated diolefin polymers, e.g. SBR rubbers, are recovered from their aqueous polymerization emulsion by coagulation with acid and a lignin compound. The conventional use of sodium chloride as a coagulant is avoided so as to overcome the problem of sodium chloride in the effluent. By this process of the invention, a rubber crumb of increased porosity is obtained, which is easier to dry.

Abstract: This polymer comprises (a) about 15 to 5 weight percent of units from at least one nitrile monomer of the formula ##STR1## where R is hydrogen or methyl; (b) about 75 to 90 weight percent of units from vinylidene chloride, and (c) about 10 to 5 weight percent of units from at least one acrylate monomer of the formula ##STR2## where R' is hydrogen or alkyl of 1 to 4 carbon atoms and R" is alkyl of 1 to 20 carbon atoms.

Abstract: Free flowing polychloroprene powder can be produced from standard latexes by adding 1 - 10% of a salt of an alkyl sulfate, such as sodium lauryl sulfate to an acidified latex and precipitating the rubber in a coagulating solution, separating the particles and drying them. It was also found that the precipitated polychloroprene particles could be made stable in alcohols and ketone (which affords a simpler drying procedure) by adjusting the pH of the mixture of latex and coagulating solution to about 7.25.

Abstract: This invention relates to a novel process of preparing chloroprene polymer rubber granules. The process comprises adding 4 to 10 wt. parts of sodium silicate to 100 wt. parts of a cationic latex of chloroprene polymer and then adding an alkaline earth metal salt or an acid to precipitate granules of the chloroprene polymer rubber.

Abstract: Removal of dissolved vanadium catalyst residues from .alpha.-olefin polymer solutions improves the heat stability of the polymer recovered therefrom. Vanadium residues are removed from .alpha.-olefin polymer solutions in inert solvents by contacting the solutions at 50.degree.-225.degree.C. with one or more active metals, either in their elemental form or as alloys, selected from alkali metals, aluminum, and zinc, and separating the solutions from vanadium residues precipitated thereby. The process can be carried out continuously by passing the polymer solution through a column containing the active metal.

Abstract: A polymerization reaction product comprising a solution of a poly(1-alkene) and a hydrocarbon polymerization solvent is purified of Ziegler-Natta aluminum and titanium containing catalyst residue by treating with flux-calcined diatomite to deactivate and insolubilize the aluminum and titanium and filtering out the insolubilized aluminum and titanium.