Abstract: An improvement in the method of preparing vinyl halide-containing polymers by suspension polymerization is disclosed. Briefly, the improvement comprises "tail-peaking" the reaction mass prior to stripping in order to remove vinyl halide. By "tail-peaking" is meant increasing the temperature of polymerization towards the latter part of the polymerization reaction. In one aspect the improvement comprises the additional feature of conducting the polymerization in the presence of a plasticizer.

Abstract: Modified polymers, particularly polyolefins having improved flow and in some instances improved adhesion properties over that of a polymeric, e.g. polyolefin, base stock used as a starting material, are produced by a controlled reaction often involving degradation in an extruder, in which an initiator is injected under conditions of either maximum distribution or intensive mixing wherein appreciable rheological, i.e. molecular weight distribution, changes in said base polymer occur. In some embodiments monomers are also grafted to said base stock, during said degradation process. In such instances, exceptional, novel, grafted polymers with high melt flow properties and other useful properties are obtained.

Abstract: Crude graft products of styrene on polyolefinic rubbers in which, in the gel, the polystyrene/polyolefinic rubber ratio is shifted to relatively high polystyrene contents, always higher than 1:1, and which graft products are characterized by a satisfactory, which is to say commercially acceptable, distribution of the rubber particles in the polystyrene matrix are obtained by subjecting a solution of a polyolefinic rubber or elastomer in styrene to polymerizing conditions in aqueous phase in the presence of a radical initiator and of a chain transfer agent.

Abstract: The invention relates to a method for producing a thermoplastic resin useful particularly as an engineering plastics, which comprises suspending in an aqueous medium a solution comprising (a) a non-polar rubbery polymer having an iodine value of 2 to 40, (b) an aromatic vinyl monomer, (c) an aliphatic vinyl monomer, and a small amount of an organic solvent, and suspension-polymerizing in the presence of a polymerization initiator.

Abstract: Polymerization of a monomer, either alone or present in major proportion with one or more comonomers present in minor proportion, is accomplished by controlling the major monomer feed rate in response to a signal representative of the production rate of the polymerization process, unless the major monomer concentration within the reaction zone exceeds a preselected high limit causing the major monomer feed rate to be controlled in response to the concentration of the major monomer within the reaction zone. The flow of recycle diluent to the reaction zone is controlled in response to the concentration of major monomer within the reaction zone unless the solids concentration within the reaction zone exceeds a preselected high limit, in which case the flow of recycle diluent to the reaction zone is controlled in response to the concentration of solids within the reaction zone.

Abstract: A polypropylene molding composition having an excellent impact strength at a temperature down to -60.degree. C and simultaneously a good hardness contains from 70 to 90% by weight of a polypropylene, 2 to 10% by weight of an ethylene propylene copolymer and 8 to 25% by weight of a polyethylene and is distinguished by a melt index MFI 230/5 lower than that of the polypropylene contained therein and simultaneously higher by the coefficient 1.3 to 7.0 than that of a polypropylene prepared in the presence of the same catalyst as the molding composition and having the same RSV.

Abstract: Unsaturated carboxylic acids are grafted onto copolymers of ethylene and carboxylates. Carboxylic acid containing initiator is caused to diffuse into shaped elements of the copolymers, polymerization then being carried to completion by heating. The products exhibit no fish eyes and are highly suitable for sheet manufacture.

Abstract: A method of suspension polymerization, which is effective to prevent the adhesion of scale-form polymer to the inside wall of polymerization vessel, is provided by adding oxalic acid or its salt to the polymerization system consisting of vinyl chloride suspended in aqueous medium.

Abstract: Process for producing a water-soluble polymer comprising polymerizing an ethylenically unsaturated monomer yielding a water-soluble polymer in an aqueous medium in a polymerization vessel, characterized in that the polymerization system is maintained without stirring at least after the polymerization is initiated, the temperature of the polymerization system is permitted to rise on its own accord, and the non-uniformity of temperature distribution between the center and surroundings of the polymerization system due to the temperature rise is eliminated by heating the polymerization system from the outside.

Abstract: An olefin is polymerized in a hydrocarbon diluent in a turbulent reaction zone to produce particles of polymer which are substantially insoluble in the diluent. Fouling of the reactor by adherence of polymer particles to the walls of the reactor is reduced by adding to the reaction medium a composition which comprises a mixture of an aluminum or chromium salt of an alkyl salicylic acid and an alkali metal alkyl sulfosuccinate.

Abstract: Encrustations on reactor walls and associated equipment employed in the aqueous suspension polymerization of vinyl chloride and mixtures thereof with other monomers at 30.degree.-70.degree. C. are prevented by employing in the polymerization charge 0.0005 - 0.05% by weight of hydrogen peroxide, calculated on the monomer or monomers, preferably at a pH of at least 7.5, e.g., 7.5 - 8.5 when using a suspending agent which is sensitive to hydrolysis.

Abstract: Finely powdered high density polymer may be obtained by spraying a solution of a critical maximum amount of a polymer, such as 3 weight % polypropylene in heptane, into a drying atmosphere in which said solvent has a vapor pressure of 50 to 400 mm of Hg.

Abstract: The viscosity of a solution of graft copolymer resulting from solution graft copolymerization is greatly reduced, and the handling characteristics are improved, by adding water and a suspending agent to the solution to form a suspension. E.g., to a reaction solution resulting from grafting of styrene and acrylonitrile on EPDM in solution, there is added 20 parts water and 0.1 part polyvinyl alcohol, and the mixture is agitated to produce a low-viscosity suspension.

Abstract: A method of measuring the extent of an exothermic chemical reaction while the reaction is proceeding which comprises measuring the difference between the ingoing and outgoing temperatures of a coolant passing through the reaction vessel and computing therefrom the heat produced by the reaction, and in which the numerical value of the temperature of the ingoing coolant is retained in a memory device before being compared with that of the outgoing coolant, the period of retention being equal to the time taken for coolant to pass from the point of measurement of the ingoing temperature to the point of measurement of the outgoing temperature. This corrects errors due to variations with time of the temperature of the ingoing coolant.

Abstract: A method is provided for controlling polymer particle size in emulsion polymerization in which at least one emulsifier is added to a polymerization reaction mixture containing at least one ethylenically unsaturated monomer at a rate determined by the rate at which heat is evolved by free radical catalyzed polymerization of the monomer such that the total amount of emulsifier fed to the reaction mixture up to any one time is related to the total amount of heat evolved up to that time.

Abstract: High softening point resins are prepared by a process which comprises polymerizing in the presence of a Friedel-Crafts catalyst a mixture of (1) a feedstock comprising C.sub.5 olefins and diolefins, C.sub.6 olefins and diolefins or a mixture of C.sub.5 and C.sub.6 olefins and diolefins, said feedstock being obtained from the steam-cracking of petroleum feedstock and (2) a polymer obtained by the thermal or cationic polymerization of dicyclopentadiene, an alkyl cyclopentadiene dimer, a codimer of cyclopentadiene with an alkyl cyclopentadiene, a codimer of cyclopentadiene or an alkyl cyclopentadiene with a C.sub.5 or a C.sub.6 conjugated linear or non-cyclic diolefin, or a mixture of said dimer and codimers. The resin may be mixed with rubber to make a pressure-sensitive adhesive.

Abstract: Ethylene polymers are produced at pressures between 1000 and 4000 atmospheres and temperatures of from 120.degree. to 300.degree. C in a reaction zone having an 1/d ratio of from 10:1 to 20:1 while shear forces act on the reaction mixture. The ethylene is fed continuously and radially to the reaction zone at a velocity of from 2 to 20 m/sec. The average residence time of the reaction mixture in the reaction zone is from 20 to 90 seconds. The products show a broad molecular weight distribution and are particularly advantageous for use as extruded coatings.

Abstract: A process for polymerization or polycondensation wherein the reactor is equipped with a stirrer disposed in the interior of the reactor to be rotatable about an axis extending in the direction of the longitudinal axis of the interior of the reactor, the reactor also including inlet and discharge conduits for the reaction mass, a conduit for the removal of gaseous substances produced by evaporation during the reaction, and a heating device, and the reactor being mounted so that its longitudinal axis is inclined to the vertical so that the interior of the reactor defines a lower chamber which is to be filled with a liquid reaction mass and an upper chamber to be filled with vapors formed during the reaction, with the reaction mass discharge conduit being disposed at the lowest point of the fluid chamber and the stirrer being constructed so that its outermost parts which extend into the vapor chamber dip into the fluid chamber during each revolution of the stirrer.

Abstract: Four component polymerization initiators for olefinic monomers comprise (1) an oxidizing agent such as hydrogen peroxide, a persulphate, a permanganate, a chlorate, a perchlorate, a bichromate, a bromate, a ceric salt, an oxazirane, an organic peroxide or an organic hydroperoxide, (2) a chelate compound of a metal such as titanium, iron, vanadium, aluminum, tin, manganese, chromium, cobalt, copper, zinc or bismuth in which the metal is not fully coordinated, (3) an electron donor in amount at most equal to that required to complex completely the said metal of the chelate compound, the said electron donor being for example an amine, a monoalcohol, an ether, an aldehyde, a ketone, an imine, an oxime, an amide, a sulphonamide, or a phosphonamide, and (4) a chelate complex or salt which is different from the chelate compound (2) and in which the metal may be for example, copper, iron, magnesium, manganese, chromium, vanadium or tin, the degree of coordination of the said metal being different from that of the met

Abstract: The polymerization of vinyl chloride in aqueous dispersion is terminated by introducing 8-hydroxyquinoline into the aqueous dispersion. The preferred amount to use is 0.025 to 0.2 % by weight of the vinyl chloride employed.