Abstract: Poly-.alpha.-olefin, for example, polypropylene, is produced by subjecting a feed containing an .alpha.-olefin having 3 or more carbon atoms, to a preliminary polymerization at 40.degree. C. or less in the presence of a catalyst which comprises (A) a solid catalytic ingredient prepared (a) by reacting a Grignard compound of the formula, R.sup.3 MgX wherein R.sup.3 =C.sub.1-8 alkyl and X=halogen, with a reaction product of an aluminium halide with an organic silicon compound of the formula, R.sub.n.sup.1 Si(OR.sup.2).sub.4-n, wherein R.sup.1 =C.sub.1-8 alkyl or phenyl, R.sup.2 =C.sub.1-8 alkyl, n=0, or 1 to 3, (b) bringing the resultant solid carrier into a first contact with titanium tetrahalide, (c) treating the resultant titanium-containing solid product with an organic acid ester, and, finally, (d) bringing the treated solid product into a second contact with titanium tetrahalide; (B) another catalytic ingredient consisting of a trialkyl aluminium of the formula, AlR.sub.3.sup.4 wherein R.sup.4 =C.sub.

Abstract: Styrene-butadiene random copolymers having an average vinyl content of at least 70%, a breadth of the distribution of vinyl contents of at least 20%, a Mooney viscosity (ML.sub.1+4, 100.degree. C.) of 10 to 150, and a styrene content of about 3 to 30% by weight. They are prepared by copolymerizing styrene and butadiene in a hydrocarbon solvent in the presence of an organolithium initiator and a Lewis base and, if necessary, an anionic surface active agent containing --SO.sub.3 M or --OSO.sub.3 M (wherein M is Na, K, Rb or Cs) under temperature-raising conditions. They are rubber materials having low rolling resistance and high wet skid resistance.

Abstract: In a process for the mass polymerization of vinyl aromatic monomer wherein vinyl aromatic monomer is polymerized in successive stages of increasing temperature, the improvement which narrows the molecular weight distribution of the resulting polymer comprising incorporating a crosslinking agent into a polymerizing mass at a point where about 60 to about 95% of monomer is converted to polymer.

Abstract: A continuous process is provided for producing substantially homogeneous, non-tacky solid terpolymers of acrylamide, an alkali metal salt of acrylic acid and a hydroxyalkyl acrylate, and copolymers, optionally cross-linked, of a (meth)acrylamidoalkylsulfonic acid or alkali metal salt thereof and (meth)acrylamide or N-alkyl(meth)acrylamide, by rapidly heating a single phase high solids aqueous solution of the monomers to polymerization initiation temperature immediately prior to depositing a uniform layer of the solution and, at the same time, a solution of a polymerization initiator, onto a moving surface, the surface and the reaction mixture only being heated if necessary to keep the temperature of the polymerizing mixing from dropping substantially below the polymerization initiation temperature.

Abstract: An improved process for the high pressure polymerization of ethylene using a battery of two reactors in which the preceding autoclave reactor having two reaction zones is connected in series with the succeeding autoclave reactor having one reaction zone through a heat exchanger. This process has a high efficiency of polymerization initiator and gives a polyethylene excellent in optical properties and processability in a high reaction yield.

Abstract: There is provided a continuous, steady state process for the preparation of nonrandom ethylene/.alpha.,.beta.-ethylenically unsaturated carboxylic acid copolymers in at least 2 constant environment, stirred autoclaves in series wherein the first autoclave is maintained at the pressure in the range of 800 to 3000 atmospheres (11.8 to 44.1 kpsi) and at a temperature in the range of 120.degree. to 200.degree. C. in a single phase reaction mixture at the given concentration of copolymer in the reaction mixture and at the given acid comonomer content of the copolymer and wherein each succeeding autoclave is maintained at a temperature of at least 30.degree. C. in excess of the preceding autoclave. The compolymers thus obtained have a ratio of percent adjacent acid to weight percent acid in the copolymer of from above 0.44 to about 1.0.

Abstract: What is disclosed are copolymers predominantly containing acrylonitrile and having a very low residual monomer content, for example of less than 100 ppm, the method of making such copolymers by polymerization to at least 60 percent conversion followed by post-heating at a temperature of more than 130.degree. C., and the use of such copolymers in orthopedic devices which come into direct contact with the skin.

Abstract: Novel allyl-acrylic monomers of the formula: ##STR1## wherein R is a C.sub.1-4 alkylene group and R.sub.1 is hydrogen or methyl, are described. The preferred monomer is that in which R is ethylene and R.sub.1 is methyl. When subjected to conventional free radical polymerization, in one stage or two stages, these monomers give transparent polymers having good mechanical properties, particularly hardness.

Abstract: A process for the polymerization of butene-1 in a liquid aliphatic hydrocarbon medium in the presence of a catalyst composed of a titanium trihalide and an organoaluminum compound which comprises initially polymerizing a minor part of the butene-1 at a temperature within a range sufficiently low that a slurry of polymer in said medium is produced and then increasing the temperature of polymerization so that the greater part of the butene-1 is polymerized within a high temperature range higher than that of the initial polymerization but not at a temperature so high that the polymer formed dissolves in said medium, characterized in that (1) the initial polymerization is carried out at a temperature of not more than 20.degree. C. in the presence of said titanium trihalide in an amount of not less than 50 millimoles and up to 1,000 millimoles per liter of said medium, and then (2) the polymerization is carried out in the presence or absence of said medium at a temperature of 25.degree. C. to less than 48.degree.

Abstract: Process and device for cooling a mixture of polymer and monomer from a reactor in which ethylene is polymerized or copolymerized at a pressure greater than 1,000 bars between a pressure-reduction valve located downstream of the reactor and a medium pressure separator. The cooling is achieved by injecting monomer at a pressure below that of the separator using a device with a nozzle cross-section S.sub.1 through which the mixture from the reactor passes, a convergent mixing zone in which the mixture is mixed with the monomer injected, which is supplied at a flow rate q, and a diffuser of throat cross-section S.sub.3, which makes it possible to bring the mixture to the pressure of the separator. The dimensions of the device are such that the ratio Q/S.sub.1 is between 0.20 and 1.35 t/hr.mm2 and the ratio (q+Q/S.sub.3 is between 0.1 and 0.3 t/hr.mm2.

Abstract: In producing a low density polyethylene by a slurry copolymerization of ethylene and an .alpha.-olefin with use of a catalyst consisting of a magnesium compound-supported titanium and/or vanadium compound and an organoaluminum compound, a certain amount of ethylene is subject to a pre-polymerization in the presence of said catalyst prior to the copolymerization. Successively, the slurry copolymerization of ethylene and an .alpha.-olefin is effected in a low-boiling diluent to obtain a low density polyethylene of 0.925-0.950 in density, covering various grades in a wide range.

Abstract: A synthetic resin is produced by polymerizing with a Friedel-Crafts catalyst a C.sub.5 stream containing butadiene which has been preheated to a temperature of at least 160.degree. C. for a period of up to 5 hours.

Abstract: The present invention relates to a process for preparing vinyl dispersion resins by conducting the polymerization reaction of the vinyl monomer or monomers in an aqueous alkaline medium, using an oil-soluble polymerization initiator, at temperatures preferably below about 48.degree. C., in the presence of an emulsifier system comprising the ammonium salt of a high fatty acid containing from 8 to 20 carbon atoms, at least one long straight chain alcohol containing from 14 to 24 carbon atoms, and a sulfate or sulfonate type soap of C.sub.12 to C.sub.20 alkyl or aryl hydrocarbons, wherein the ratio of alcohol to emulsifier is equal to or greater than 1.0 and wherein the reaction ingredients are thoroughly mixed, and preferably homogenized, prior to polymerization. The process produces paste resins having improved plastisol foam properties, especially when sodium metabisulfite is added to the polymer recipe or the polymer slurry prior to spray drying.

Abstract: A steam sterilizable copolymer is prepared from 60 to 50% by weight of alpha methyl styrene and 40 to 50% by weight of methyl methacrylate. The copolymer is useful to make the barrel of syringe which is clear, water-white and shows no distortion upon steam sterilization for at least 20 minutes at 250.degree. F.

Abstract: A process and apparatus for the polymerization of ethylene in at least one multizone reactor at a pressure of 300 to 2500 bars and at a temperature of 150 to 350.degree. C. The reaction mixture is passed from the reactor to a separator at a pressure of 50 to 500 bars in which the polymer separates from the gas. The polymer is then passed to a hopper at a pressure of 1 to 20 bars in which the major part of the gas remaining dissolved in the polymer is removed. The gas from the separator is recompressed and is returned only to the first zone of the reactor.

Abstract: Polytetrafluoroethylene fine powders which have an average molecular weight of not less than 5,000,000, preferably not less than 5,500,000, an amorphous index of not more than 0.1, preferably not more than 0.09, a number average primary particle size of 0.1 to 0.4 micron, preferably 0.15 to 0.38 micron, and a sharp endothermic peak at a temperature between 343.degree. C. and 350.degree. C. on the melting diagram by a differential scanning calorimeter, said sharp peak having an endothermic ratio of not more than 0.3, preferably not more than 0.27, and a half value width of the endothermic peak of not more than 8 degrees, preferably not more than 6 degrees, and a process for producing the polytetrafluoroethylene fine powders. The polytetrafluoroethylene fine powders have an excellent stretchability and are useful for electric wire coating, small diameter tubes, large diameter tubes, sealing tapes and the like.

Abstract: A process for preparing highly stereoregular polyolefins in the presence of a catalyst comprising (A) a titanium-containing solid catalyst component composed of an organic complex derived from(i) a magnesium halide(ii) an organopolysiloxane selected from the group consisting of compounds of the formulaQ(Q.sub.2 SiO).sub.n SiQ.sub.3, (Q.sub.2 SiO).sub.n and X(Q.sub.2 SiO).sub.n SiQ.sub.2 X,(iii) an organic carboxylic acid ester, and(iv) a titanium compound of the formulaTi(OR).sub.l X.sub.4-l, and(B) an organoaluminum catalyst component of the formulaR'mAl(OR').sub.3-m,said organic complex being derived by bringing the component (i) into contact with a combination of the components (ii) and (iii) or a combination of the components (ii), (iii) and (iv) under mechanical pulverisation conditions and then treating the resulting pulverized composition with the component (iv) in the absence of mechanical pulverization.

Abstract: An improved polyvinyl halide or a polyvinyl halide copolymer containing up to 50 percent of a comonomer can be obtained by post polymerizing in a single stage or two-stage bulk process in contact with a base polymer, the same or different monomer as the monomer used to form the base polymer. Compositions produced by the process of the invention are useful in making films, coated fabrics and molded objects. The liquid phase post polymerization process of the invention is applicable to base polymers in powder form prepared by emulsion, suspension and bulk polymerization processes. The base polymer can be present in a polymerization mixture in which only a partial amount of monomer has been converted to base polymer such as in a two-stage polymerization process or the base polymer can be used in dry, solid form. Polymers of the invention have improved bulk density and reduced plasticizer uptake and can be used to prepare fabric coatings.

Abstract: An improved contact lens material is formed by a copolymer of a siloxanyl alkyl ester monomer, an itaconate ester and an ester of acrylic or methacrylic acid. The copolymer preferably includes a cross-linking agent and a hydrophilic monomer. Contact lenses made of the mterial can be readily machined and polished into hard contact lenses having excellent dimensional stability but also have extremely high permeability to oxygen.

Abstract: In casting methacrylate sheets for thermoforming applications, it has heretofore been the practice to add chain transfer agents to the polymerization mix for forming syrup. It has now been found that addition of chain transfer agent can be delayed until after the syrup has been prepared with no loss in thermoformability of sheets prepared from the syrup.

Abstract: In a process for producing substantially gel free elastomers of isobutylene and a conjugated diene selected from the group consisting of cyclopentadiene, methylcyclopentadiene, isoprene or piperylene and mixtures thereof, improved products, higher catalyst efficiency, high cement concentrations and improved monomer conversions are obtained by the use of staged, or multiple reactors whereby the monomers and/or catalyst feeds may be divided among the reaction zones. The process provides elastomers which are substantially gel free having controlled molecular weight distribution (polydispersity) and high molecular weights at about 8 to about 45 mole % unsaturation.

Abstract: This invention provides a process for preparing a transparent polymeric product free from strain and bubbles and having improved physical and chemical properties. The product can be produced from a bis-allylcarbonate-based monomer mixture by cast polymerization for extremely shortened polymerization time.

Abstract: Crystal polystyrene with improved flow properties useful in injection molding is prepared in a two-stage process in which a first portion of monomer is polymerized in the presence of about 0.3 to about 2.0% peroxide initiator to convert about 70 to 95% of the monomer present to polymer having a number average molecular weight of 20,000 to 50,000 and a weight average of 50,000 to 100,000; then adding the rest of the monomer thereby reducing the catalyst concentration to generate a second moiety of polymer so that the final product has a weight average molecular weight of 150,000-300,000, and a number average of 50,000-70,000.

Abstract: A process for the free-radical polymerization of vinyl monomers, including vinyl aromatic monomers, at at least two distinct progressively higher polymerization temperatures, each between the temperatures of about 70.degree. C to about 150.degree. C in the presence of at least two free-radical initiators, one of which initiators, used in relatively minor proportions, has the formula ##STR1## wherein x is a numeral from 1 to 5 inclusive, B is ##STR2## A is hydrocarbyl, A, is tertiary hydrocarbyl and R is A, a hydrocarbyloxy or alkylperoxy and the other initiator, used in relatively major proportions, has a 10 hour half-life temperature below about 100.degree. C. The distinct temperatures for polymerization may occur as separate parts of a polymerization in which the temperature of the system continually increases.

Abstract: A process for the free-radical polymerization of vinyl aromatic monomers in at least two thermally distinct polymerization stages each between the temperatures of about 70.degree. C and 150.degree. C in the presence of at least two free-radical initiators, one of which initiators is particularly effective at the lowest temperature stage and has the formula ##STR1## wherein R is an alkylene, alkynylene or alkenylene diradical, R.sub.1 is alkyl, alkenyl, alkyn or alkoxy and Rhd 2 is lower alkyl and R.sub.3 is hydrogen or a lower alkyl and a second of which initiators has a 10 hour half-life temperature of at least about 80.degree. C which temperature is at least about 15.degree. C above the 10 hour half-life temperature of the compound of the above formula.

Abstract: A diperoxyester mixture composition is provided comprising at least two symmetrical diperoxyesters and at least one unsymmetrical diperoxyester, a method of preparing such a composition, and the use of such a composition in vinyl monomer polymerization and in curing unsaturated polyester resin.

Abstract: Apparatus and process is herein disclosed by which a polymerizable monomer or mixture thereof can be economically and efficiently converted to polymeric substances with a high yield catalyst and, optionally, co-catalyst by a vapor phase, essentially isobaric, polymerization process using a horizontal, stirred-bed, quench-cooled, essentially total reactor off-gas recycle reactor.

Abstract: A process for the free-radical polymerization of a vinyl monomer, including vinyl aromatic monomer, at least two distinct, progressively higher polymerization temperatures, each between the temperatures of from about 50.degree. C and 130.degree. C, in the presence of at least two free-radical initiators, one of which, used in relatively minor proportions, is di-t-butyl diperoxycarbonate and the other, used in relatively major proportions, has a ten hour half-life temperature below 90.degree. C. The distinct temperatures for polymerization may occur as separate parts of a polymerization in which the temperature of the system continually increases.

Abstract: A process for the free radical polymerization of vinyl monomers, including vinyl aromatic monomers, wherein the temperature of the polymerization is progressively increased by at least 30.degree. C during the period of the polymerization a temperature range of from 50.degree. C to 160.degree. C and wherein the final temperature is at least 110.degree. C, the polymerization mass including an initiator sensitive to produce free radicals near or at the low temperature end of the range and an initiator sensitive to produce free radicals near or at the high temperature end of the range. A single entity initiator may contain peroxide functions that are actuated to produce free radicals at each of the temperature extremes of the process.

Abstract: A process for polymerizing ethylene under the high temperature and high pressure conditions by using a battery of two or more autoclave reactors connected in series by means of piping provided with a heat exchanger, each of said reactors having an upper reaction zone and a lower reaction zone. According to this process, the reaction yield of polyethylene is higher than that attainable from the conventional two-zone polymerization methods, and the obtained polyethylene is improved in optical properties and processability.

Abstract: A method of polymerizing and a polymerization column for a monomeric vinylidene compound in which heat exchange tubes are spaced relatively along a polymerization chamber, each tube lying in a radial plane of the chamber and having an ingoing length and an outgoing length, the two lengths being in the form of windings with the windings of each length lying between windings of the other.

Abstract: Auxiliary agents for improving the retention of flushable solids and for accelerating the drainage of suspensions, for more rapid treatment of solid and liquid substances which can be utilized industrially, such as industrial water, effluents and sludges, inter alia in the paper industry, and for improving the structure of soils, this auxiliary agents being in the form of suitable high-molecular, water-soluble acrylamide polymers obtained by solution polymerization, and also relates to a process for the preparation of this auxiliary agents.

Abstract: A process for preparing a polytetrafluoroethylene fine powder by polymerizing tetrafluoroethylene in an aqueous medium containing a polymerization initiator and a dispersant, coagulating the resulting polymer, washing the coagulated polymer when desired, and drying the polymer, characterized in that after at least 30 wt. % of the whole amount of the tetrafluoroethylene to be polymerized has been polymerized at a constant temperature, the polymerization is conducted at an altered temperature at which the same whole amount, when polymerized, gives a polymer having an amorphous index at least 0.01 higher than when the whole amount is polymerized at the first-mentioned temperature.

Abstract: A two-stage cyclical process for producing alkene polymers of wide molecular weight distribution, in which high molecular weight polyalkenes are produced in one stage and lower molecular weight polyalkenes are produced in the other stage and in which polyalkene from one of said stages is introduced into the other of said stages.

Abstract: The present invention is directed to a method for preparing a reproducible synthetic carbon precursor by the autoclave polymerization of indene (C.sub.9 H.sub.8) at a temperature in the range of 470.degree.-485.degree. C, and at a pressure in the range of about 1000 to about 4300 psi. Volatiles in the resulting liquid indene polymer are removed by vacuum outgassing to form a solid carbon precursor characterized by having a relatively low melting temperature, high-carbon yield, and high reproducibility which provide for the fabrication of carbon and graphite composites having strict requirements for reproducible properties.

Abstract: In a process for polymerizing ethylene in a two-zone autoclave reactor comprising a top reaction zone and a bottom reaction zone which process comprises polymerizing ethylene in said top reaction zone at 130.degree. to 200.degree. C and at a reaction pressure of 1,000 to 1,800 kg/cm.sup.2 using an initiator, sending the resulting reaction mixture from the top reaction zone to the bottom reaction zone, and further promoting the polymerization at 220.degree. to 280.degree. C using an initiator which is same as or different from the initiator in the top reaction zone, the improvement which comprises feeding 75% or more of the ethylene to the top reaction zone of the two-zone reactor, said two-zone reactor being constructed so that the volume ratio of top reaction zone to bottom reaction zone is 1.5 to 6 and being provided with two or more feed inlets for each of the ethylene and the initiator in the top reaction zone in the direction extending through the two reaction zones.

Abstract: A vinyl acetate copolymerizate of monomers being a free-radical polymerized copolymerizate having monomer units consisting essentially ofA. from 60% to 80% by weight of vinyl acetate units,B. from 10% to 20% by weight of units of a maleic acid diester with a straight-chained alkanol-1 having from about 8 to 10 carbon atoms,C. from 5% to 20% by weight of units of a mono-olefinically unsaturated ester having from 6 to 8 carbon atoms and a hydrophilic group, andD. from 3% to 10%, particularly 7%, by weight of crotonic acid; as well as an alcoholic solution thereof and salts thereof.

Abstract: A process for the polymerization of aromatic vinyl compounds and their copolymerization with alkyl esters or nitriles of acrylic and/or methacrylic acid, wherein1. in a first stage, the monomer or monomers is or are continuously introduced at excess pressure into a first reaction zone and polymerized there to a degree of conversion of 5 - 40% by weight at a temperature of from 80.degree. to 170.degree. C;2. in a second stage, the reaction mixture is conducted at constant pressure into a second reaction zone designed for conducting highly viscous melts, the mixture flowing through this reaction zone at a rate which is 1.1 to 5 times the intrinsic rate, and polymerized there to a degree of conversion of 40 to 95% at temperatures of from 120.degree. to 250.degree. C, the excess pressure in the first and second stage being chosen so that the monomer or monomers is or are liquid, and the polymer is continuously removed from this zone with release of the pressure; and3.

Abstract: Process for manufacturing finely divided polymers of bicyclo [2.2.1] heptene-2 compound comprising the steps of incompletely polymerizing said bicyclo [2.2.1] heptene-2 compound by the ring opening polymerizing technique in the presence of a catalyst system selected from the group comprising a compound of a noble metal of the platinum family and an alcohol-reducing solvent and tungsten hexachloride, an aluminum alkyl and an aromatic solvent, under superatmospheric pressure and in the presence of a quantity of solvent at least equal to that necessary for the solution of said catalyst system and abruptly reducing said pressure at a temperature higher than the vaporization temperature of the reaction mixture under said reduced pressure, whereby an expansion, a division and at least partial drying of the resulting polymer is obtained.

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: High density polyolefin blends having good rheological properties are formed by combining low molecular weight polymers with high molecular weight polymers using a specified blending method.

Abstract: A polymerization process for producing rubbery polymers or random copolymers having excellent physical properties as well as good processability, and completely freed from a flow at normal temperature. The process, which may be called as "Low-temperature Pretreatment Polymerization process," comprises polymerizing conjugated dienes or copolymerizing conjugated dienes and monovinyl substituted aromatic compound under a specific polymerization conditions in the presence of an alkyllithium catalyst to produce a polymer or random copolymer of the desirably controlled structure of branches to afford such excellent properties mentioned above.

Abstract: In a process for preparing homo- or co-polymer of ethylene, in which ethylene alone or mixed with one or more other unsaturated organic compounds capable of forming a copolymer with ethylene is subjected to a high pressure and a high temperature in a reactor in the presence of an initiator or a catalyst, in which the mixture of polymer and unconverted monomer discharged out of the reactor is expanded to, practically, atmospheric pressure with the aid of an expansion device in two or more steps, and in which the polymer present in the expanded mixture is separated from the mixture in the solid state, the improvement which comprises obtaining the polymer in a fibrous form by supplying the mixture to the last stage of the expansion device at such a pressure and temperature that, during the expansion, in this last stage, the polymer passes from the liquid phase to the solid phase.

Abstract: A thermally-staged process for preparing polymers, particularly alternating interpolymers of one or more polar monomers and one or more mono or polyolefins which comprises: (1) reacting, in a first stage, a polar monomer-Lewis Acid complex with an olefin in the presence of an active oxygen compound at a temperature of about -100.degree.C to about 0.degree.C for a time sufficient enough to allow for conversion of up to 50% of the polar monomer to interpolymer; (2) raising the temperature of the reaction mixture, in a second stage, to about 0.degree. to about 100.degree.C; (3) maintaining the reaction mixture at about 0.degree. to about 100.degree.C for a time sufficient to optimize the yield of interpolymer; and (4) recovering the interpolymer from the reaction mixture.Polymers prepared by the temperature-staged process of this invention possess substantially higher molecular weights than the same polymers made by prior art processes.

Abstract: Polymerization of vinyl chloride in aqueous suspension in the presence of free-radical initiators of short half-life at pH's below 8. The temperature of the reactor wall must not be more than 20.degree.C above the temperature of the polymerization mixture during the heat-up phase and it must be lower than the temperature of the polymerization mixture during the subsequent polymerization phase. This procedure suppresses the formation of incrustations in the reactor.

Abstract: A polyethylene composition of high wear resistance and a method of preparing it which comprises a polyethylene prepared according to a low pressure polymerization process and which has a molecular weight above about 1,000,000, containing an organic peroxide cross-linking agent homogeneously dispersed in the polymer, which has been pre-compressed at a high pressure, plasticized at elevated temperature and pressure and cooled.

Abstract: Vinyl halide homopolymers, particularly polyvinyl chloride, which exhibit improved processing characteristics without sacrificing physical properties are prepared by partially polymerizing a vinyl halide monomer at an initial temperature level whereupon the reaction temperature is then raised and the polymerization is continued at this increased temperature level preferably while in the presence of a chain transfer agent so as to obtain a polymer having an average molecular weight range different from that obtainable at the first reaction temperature. The resulting polyvinyl chloride provides the physical characteristics of polymer blends but can be processed much more readily than a mechanical blend of homopolymers of varying molecular weights, fusing more easily and without the undesirable formation of fish eyes.

Abstract: The present application discloses a polymeric plastic material suitable for contact lenses. It is made from a monomer having the formula ##EQU1## wherein n is 2 or 3, in the substantial absence of diunsaturated and polyunsaturated monomers. The mixture subjected to polymerization may also contain as an additional comonomer a compound having the formula ##EQU2## wherein R is hydrogen or CH.sub.3, and R' is a lower alkyl group, or a group (C.sub.2 H.sub.4 O).sub.m H where m is an integer of at least 1. The application also discloses a post-heating or post-curing step, the machining of the plastic into contact lenses followed by washing in dilute alkali to neutralize any residual acid material within the plastic, followed in turn by heating in normal saline or isotonic solution to make the lens compatible with the eyeball.

Abstract: A melt finish process is disclosed herein for working up solid, particulate polymer from a vapor state polymerization reactor, which reactor employs high yield catalysts, whereby the polymer is moved out of the reactor and into a post polymerization zone characterized by essentially adiabatic polymerization and the heat of such polymerization is used in raising the temperature of and melting said solid, particulate polymer to form molten polymer for further processing.

Abstract: Polytetrafluoroethylene fine powders which have an average molecular weight of not less than 5,000,000, preferably not less than 5,500,000, an amorphous index of not more than 0.1, preferably not more than 0.09, a number average primary particle size of 0.1 to 0.4 micron, preferably 0.15 to 0.38 micron, and a sharp endothermic peak at a temperature between 343.degree. C. and 350.degree. C. on the melting diagram by a differential scanning calorimeter, said sharp peak having an endothermic ratio of not more than 0.3, preferably not more than 0.27, and a half value width of the endothermic peak of not more than 8 degrees, preferably not more than 6 degrees, and a process for producing the polytetrafluoroethylene fine powders. The polytetrafluoroethylene fine powders have an excellent stretchability and are useful for electric wire coating, small diameter tubes, large diameter tubes, sealing tapes and the like.