Abstract: A method for producing a tetrafluoroethylene/perfluoro (alkyl vinyl ether) type copolymer (PFA), which comprises carrying out the polymerization in a polymerization medium (such as CHFClCF2CF2Cl) in the presence of a chain transfer agent of a C1 or 2 hydrofluorocarbon (such as CH3CF2H) by means of a polymerization initiator (such as (FCF2CF2CF2COO)2). PFA obtained by this method has a small amount of unstable terminal groups contained in its molecule and is excellent in thermal stability and cracking resistance against a liquid reagent. Further, the amount of elution of fluorine ions is little even when it is applied to a component of e.g. an equipment for the production of semiconductors.

Abstract: It has been discovered that the polymerization of diene compounds, such as butadiene, may be inhibited by the addition of a composition that contains at least one hindered or unhindered phenol, in combination with low nitrogen content component which is a stable nitroxide and/or a hydroxylamine substituted with at least one alkyl, aryl or alkylaryl group; and/or a second, different hindered or unhindered phenol, and optionally a hydrogen transfer agent.

Abstract: It has been discovered that the polymerization of unsaturated compounds, such as butadiene, may be inhibited by the addition of a diene and/or alkanolamine inhibitor. The inhibitor is believed to catalytically destroy peroxides present, such as hydrogen peroxide, which may be present in trace amounts. Particularly useful inhibitors include, but are not limited to, ethylenediamine (EDA) and monoethanolamine (MEA).

Abstract: This invention relates to a process for the synthesis of addition polymers containing branches upon branches and having a polymerizable olefin end group by a convenient one-pot polymerization of selected vinyl monomers with chain polymerization initiators and a method to provide olefinic end groups by chain termination agents; and polymers produced thereby characterized by branch-on-branch structure and lower inherent viscosity than heretofore possible.

Abstract: The invention relates to a method for polymerizing or copolymerizing ethylenically unsaturated monomers in the presence of radically decomposing polymerization initiators in a continuously operating polymerization device. Said polymerization device is composed of a fresh gas supply, a pre-compressor, a post-compressor, a reactor, a pressure maintaining valve, of a high-pressure circuit, which is provided with a high-pressure product separator and with a high-pressure circuit gas return, and of a product valve and a low-pressure circuit, which is provided with a low-pressure product separator and with a low-pressure circuit gas return. The inventive method is characterized in that nitrogen monoxide or oxygen is added in a dosed manner as an inhibitor into the high-pressure circuit, into the low-pressure circuit and/or into the pre-compressor.

Abstract: Methods and compositions for inhibiting the polymerization of vinyl monomers are disclosed. Combinations of aminophenol compounds and nitroxyl radical compounds are effective at inhibiting vinyl monomer polymerization under both processing and storage conditions.

Abstract: A process for purifying N-vinyl-&egr;-caprolactam comprises converting the N-vinyl-&egr;-caprolactam which is to be purified and has a purity of at least 95% by weight into a melt, partially crystallizing the melt and separating the crystals from the mother liquor.

Abstract: A subject matter of the invention is a batchwise process for the manufacture of an optical fiber made of polymers, the core of the fiber being based on methyl methacrylate. This process is carried out in an in-line plant leaktight with respect to the outside ranging from a device for the purification of the starting materials to a spinning device, involving the intermediacy of an intermediate storage region. The core of the fiber is prepared from beads of a polymer based on purified methyl methacrylate obtained by aqueous suspension polymerization.

Abstract: A method of producing a vinyl-based polymer is provided in which the blocking of piping resulting from solidification of a reaction inhibitor does not occur even if the operation of supplying the reaction inhibitor is conducted at a low temperature. This method involves the polymerization of a vinyl monomer via a radical reaction, wherein a reaction inhibitor formed from a compound represented by a general formula (1), shown below, is added to the polymerization system in the form of an aqueous dispersion, either prior to commencement of the polymerization, during the polymerization, or following completion of the polymerization, depending on the effect desired.

Abstract: A multi-stage process for preparing ethylene (co)polymers having broad molecular weight distributions is disclosed, said process comprising: (A) a first polymerization stage in which, in the presence of a Ti or V catalyst, a first ethylene polymer is prepared; (B) a treatment stage in which the catalyst used in the first stage is deactivated and in which a bridged bis-2-indenyl zirconocene is supported on the ethylene polymer produced in stage (A), optionally in the presence of a suitable cocatalyst; and (C) a second polymerization stage in which ethylene is polymerized in the presence of the product obtained from stage (B). Furthermore, polyethylene obtainable by the above process is disclosed, having intrinsic viscosity ranging from 0.5 to 6 dl/g, Mw/Mn>8 and cold xylene solubility<1.2 % wt.

Abstract: In a packed column handling an easily polymerizing substance, the packing with which the column is stuffed is subjected to a water-repelling treatment or a wetting treatment to prevent the easily polymerizing substance in the packed column from polymerizing. By preventing the occurrence of a polymer, it is made possible to ensure continuous production of an easily polymerizing substance-containing solution and decrease the content of the easily polymerizing substance in the product and consequently improve the quality of the product.

Abstract: The present invention relates to a method for the isolation of olefins from a gas mixture comprising one or more olefins, inert gas and catalyst poison, where the gas mixture is fed to a separation unit (18) and separated into olefin and inert gas. The method according to the invention has the special feature that an apparatus (17) is installed upstream or downstream of the separation unit (18) and that i) in the case of an upstream apparatus (17), the catalyst poison is at least partially removed from the gas mixture, and ii) in the case of a downstream apparatus (17), the catalyst poison is at least partially removed from the separated-off olefin. The olefins here are preferably isolated from a gas mixture formed as offgas in catalytic gas-phase polymerization for the preparation of polyolefins. The recovery of the olefins from the offgas is of economic importance.

Abstract: This invention relates to a method to start up an olefin polymerization process comprising:

Abstract: The present invention relates to a catalyst composition and a method for making the catalyst composition of a polymerization catalyst and a carboxylate metal salt. The invention is also directed to the use of the catalyst composition in the polymerization of olefin(s). In particular, the polymerization catalyst system is supported on a carrier. More particularly, the polymerization catalyst comprises a bulky ligand metallocene-type catalyst system.

Abstract: The present invention discloses processes and apparatus for the efficient and rapid conversion of an elastomeric monomer to a polymerized elastomer, and conjointly, reaction of the resultant rubbery polymer into a monovinylaromatic polymerization reaction to form a rubber-modified polymer; and more specifically teaches a method of polymerizing butadiene and reacting it with styrene monomer to form a transparent rubber-modified impact-resistant polystyrene material exhibiting elastomer concentrations that range from as low as 6 weight percent or lower, to as high as about 50 percent.

Abstract: The invention relates to a process for the preparation of polymers containing N→O terminal groups and to compositions comprising polymers obtained by this process. The process comprises polymerizing by atom transfer radical polymerization (ATRP) an aliphatic monomer of oligomer containing ethylene groups in the presence of a polymerization initiator.

Abstract: The invention relates to a process for the manufacture of a solid catalytic component for the polymerization or copolymerization of olefins, resulting in a polymer or copolymer with broadened molecular mass distribution. The process includes a first stage including bringing into contact a) a solid support including at its surface at least 5 hydroxyl groups per square nanometre (OH/nm2) and b) an organic magnesium derivative, and optionally, preferably, c) an aluminoxane, to obtain a first solid, and then a second stage including bringing the first solid and a chlorinating agent into contact to obtain a second solid and then, in a later stage, impregnation of the second solid with a transition metal derivative.

Abstract: A process for the gas phase polymerization of one or more alpha-olefins in the presence of a polymerization catalyst system under reactive conditions in a fluidized bed reactor which process comprises introducing into the reactor a deactivating agent characterized in that the deactivating agent is introduced close to the reactor wall and that said introduction does not terminate the polymerization reaction.

Abstract: The present invention relates to the use of thermally triggered compounds that when used with a polymerization catalyst in a polymerization process results in the controllable generation of one or more catalyst inhibitors that renders the polymerization catalyst substantially or completely inactive.

Abstract: The invention relates to a process for transitioning from polymerizing sticky polymer to polymerize another sticky polymer in gas phase fluidization bed production to decrease transition time, reduce off-grade material, and/or prevent operational difficulty.

Abstract: This invention discloses a process for synthesizing random styrene-butadiene rubber comprising: (1) continuously charging 1,3-butadiene, styrene, an initiator, and a solvent into a first polymerization zone, (2) allowing the 1,3-butadiene and styrene to copolymerize in the first polymerization zone to total conversion of 60 to 90 percent to produce a polymer cement containing living styrene-butadiene chains, (3) continuously charging the polymer cement containing living styrene-butadiene chains and additional 1,3-butadiene monomer into a second polymerization zone, wherein from 20 to 40 percent of the total amount of 1,3-butadiene changed is charged into the second polymerization zone, (4) allowing the copolymerization to continue in the second polymerization zone to a conversion of the 1,3-butadiene monomer of at least 90 percent, wherein the total conversion of styrene and 1,3-butadiene in the second polymerization zone is limited to a maximum of 95 percent, (5) withdrawing a polymer cement of random styren

Abstract: In a polymerization reaction, an upset is anticipated and inhibited by monitoring at least one reaction condition and comparing it to the desired value or normal range for the condition as projected by a computer model for the variable or variables of the process. In a preferred variation, the process not only continuously adjusts the set point or range for an upset-significant variable such as temperature, but also utilizes the rate of change of such a variable as a harbinger of an upset.

Abstract: A process for the gas phase polymerization of one or more alpha-olefins conducted in the presence of a catalyst in a reactor having a fluidized bed, in which process, one or more zones having a temperature greater than the average bed temperature are formed at or in close proximity to the reactor wall, comprising the step of deactivating said zones by the introduction into the reactor of an effective quantity of carbon monoxide.

Abstract: An aqueous phase inhibitor for quenching free radical polymerization comprising a free radical quenching agent having a hydrophilic tail is disclosed, as well as a coating and related methods. In one embodiment, the free radical quenching agent can either be an N-hydroxylamine or an N-nitrosonamine, the hydrophilic tail can be a polyhydric alcohol tail and the inhibitor can be a concentrate in a liquid medium such as water, alcohol and mixture thereof.

Abstract: The present invention is directed to copolymers of norbornene and functional group containing norbornene comonomers and processes for the preparation thereof. These polymers may be random, alternating or block copolymers or terpolymers, etc. In general, the present invention describes a polymer composition of the formula: [A]S— and —[B]T wherein A is monomer repeat unit derived from one or more norbornene or substituted norbornene monomers and B is a monomer repeat unit derived from one or more functionalized norbornene compounds.

Abstract: The present invention relates to the use of at least one acid and at least one base and/or at least one reductant and at least one oxidant that when used with a polymerization catalyst in a polymerization process results in the controllable generation of a catalyst inhibitor that renders the polymerization catalyst substantially or completely inactive.

Abstract: Process for the emergency stopping of a polymerization reaction in the gas phase, comprising the injection of a poison of the reaction into a polymerization reactor and the evacuation of the gaseous content of the polymerization reactor via delaying means to a burner at the maximum limited feed rate, characterized in that the delaying means simultaneously serve to obtain a homogeneous distribution of the poison of the reaction inside the polymerization reactor so as to interrupt the polymerization reaction, and to regulate the flow of gasses evacuated to the burner so as not to exceed the maximum feed rate of the burner.

Abstract: A process for regenerating unreacted vinyl chloride monomers is provided which has the step of compressing by means of an compressor an unreacted vinyl chloride monomer recovered from a process of vinyl chloride polymer production; compressing the same in contact with a lubricating oil fed into the compressor. In this process, the lubricating oil contains a polymerization inhibitor. Hence, even when this lubricating oil is circulated and reused as a lubricating oil after its separation from the unreacted vinyl chloride monomer, any vinyl chloride monomer remaining in the lubricating oil can effectively be kept from polymerizing in lubricating-oil circulation lines.

Abstract: A method is disclosed for preventing the polymerization of (meth)acrylic acid and esters thereof, which method is characterized by using an N-nitrosophenyl hydroxyl amine or a salt thereof, an N-oxyl compound, an N-hydroxy-2,2,6,6-tetramethylpiperidine compound, and a 2,2,6,6-tetramethylpiperidine compound in combination in a purifying column. The N-nitrosophenylhydroxylamine or the salt thereof is partly decomposed in the purifying column and is allowed to ascend the interior of the column and effectively inhibit the polymerization of (meth)acrylic acid. Since the method does not need to use any metal compound, it permits the disposal of the waste liquid to be effected easily. Further, the combined use of the relevant components ensures effective prevention of the polymerization in the gas and the liquid phase.

Abstract: A curable resin composition containing (A) an aromatic diallyl compound, (B) an acid derivative or an aliphatic group-containing compound having at least 4 (meth)acryl groups in one molecule, (C) divinylbenzene, and (D) a polythiol compound having at least two mercapto groups in one molecule provides an optical material having a desirable refractive index, Abbe number and transparency, and excellent heat resistance.

Abstract: The invention includes a method for evaluating the polymer growth inhibition ability of a compound or compounds. The invention involves adding a soluble monomeric, oligomeric, or polymeric seed capable of growing via a living polymerization mechanism to a liquid monomer under test conditions capable of causing a living polymer to grow via a living polymerization mechanism. Subjecting the same liquid monomer to the same test conditions then occurs in the absence of the soluble monomeric, oligomeric, or polymeric seed. Comparing the results of the two steps is then performed wherein the polymer growth inhibition ability of the compound or compounds is determined by the difference in the results. Another embodiment of the invention includes a method for evaluating the polymer growth inhibition by adding the soluble monomeric, oligomeric, or polymeric seed to the same liquid monomer solution under the same test conditions.

Abstract: The polymerization rate of olefins polymerizations using late transition metal catalysts which are coordinated to various ligands may be controlled by the amount of hydrogen present in the polymerization. The effect of hydrogen on polymerization rate is reversible.

Abstract: A pressure-sensitive adhesive sheet prepared by coating a composition containing a) 100 parts by weight of monomers composed of from 70 to 100% by weight of a (meth)acrylic acid alkyl ester, said alkyl group having from 2 to 14 carbon atoms, and from 0 to 30% by weight of a monoethylenically unsaturated monomer copolymerizing therewith, b) from 0.1 to 5 parts by weight of a radical chain inhibitor, c) from 0.02 to 5 parts by weight of a polyfunctional (meth)acrylate as a crosslinking agent, d) from 0.005 to 1 part by weight of a photopolymerization initiator, and e) from 0.01 to 10 parts by weight of a silane coupling agent, on a releasing-treated film having a good surface smoothness and photopolymerizing the coated layer to form a pressure-sensitive adhesive layer having a haze value of 1% or lower and a total light transmission of at least 90%.

Abstract: The process for producing bead polymers having a mean particle size of 0.5 to 50 &mgr;m and a narrow particle size distribution by polymerisation of monomers dissolved in a solvent that constitutes a precipitation agent for the polymers obtained from these monomers is characterized in that the solvent contains 5 to 3000 ppm of sulfur-free radical interceptors.

Abstract: Process for the synthesis of block polymers, homopolymers and copolymers of narrow polydispersity having formula (1) by contacting selected vinyl monomer(s), vinyl-terminated compound(s) and free radicals in which effective control of production of polymer is achieved by controlling the mole ratio of vinyl monomer(s), vinyl-terminated compound(s) and free radicals relative to one another; and polymers produced thereby

Abstract: A method for transitioning between two different catalysts in olefin polymerizations, a first catalyst and a second catalyst, comprising the steps of: discontinuing the feed of the first catalyst into the polymerization reactor, and introducing the second catalyst into the reactor, wherein the transition is performed between a chromium-based catalyst and a metallocene catalyst.

Abstract: A method for controlling any increase in Mooney viscosity during aging of siloxane-functionalized polymers includes the step of adding a viscosity stabilizing effective amount of a long chain alcohol preferably selected from the group consisting of aliphatic, cycloaliphatic, and aromatic alcohols having more carbon atoms than the hydrolyzable substituent on the siloxane end groups. The method provides for the stabilization of Mooney viscosity of siloxane-functionalized polymers at any given level upon aging. The long chain alcohols react with the siloxane-functionalized polymers prior to hydrolysis of the siloxane end groups to form moisture stabilized polymers.

Abstract: An improvement in a method for evaluating the efficiency of polymerization inhibitors is disclosed, wherein the improvement comprises: A) producing dissolved polymer in a solution comprising monomer and at least one inhibitor by means of any test known in the art to be useful for evaluating polymerization inhibitors, B) collecting the polymer-containing solution, C) measuring the degree of polymerization of the monomer in the collected solution, and D) re-subjecting the polymer-containing solution to the test conditions of A).

Abstract: A multi-stage process for preparing ethylene (co)polymers having broad molecular weight distributions is disclosed, said process comprising: (A) a first polymerization stage in which, in the presence of a Ti or V catalyst, a first ethylene polymer is prepared; (B) a treatment stage in which the catalyst used in the first stage is deactivated and in which a bridged bis-2-indenyl zirconocene is supported on the ethylene polymer produced in stage (A), optionally in the presence of a suitable cocatalyst; and (C) a second polymerization stage in which ethylene is polymerized in the presence of the product obtained from stage (B). Furthermore, polyethylene obtainable by the above process is disclosed, having intrinsic viscosity ranging from 0.5 to 6 dl/g, Mw/Mn>8 and cold xylene solubility<1.2% wt.

Abstract: A process for preparing homopolymers and copolymers of addition polymerizable monomers, or mixtures of such monomers, and the resulting polymer, wherein the process comprising contacting said monomer or mixture under high monomer conversion polymerization conditions with a catalyst composition comprising: a) a catalyst system comprising a Group 3-10 metal complex; and c) a silane, or hydrocarbylsilane corresponding to the formula: JjSiH4−j or AnJjSiH4-(n+j)  wherein: J is C1-40 hydrocarbyl, A is a C2-20 alkenyl group, n is 1 or 2, and j is 0 or 1; wherein the polymer comprises from 0.1 to 100 long chain branches per 10,000 carbons, and at least some of which comprise a silane branching center.

Abstract: The present invention relates to a process for the preparation of microencapsulated polymers having a high surface smoothness, a soluble fraction of less than 6%, and a swelling index of between 1.3 and 9 by polymerizing a microencapsulated monomer mixture suspended in an aqueous phase containing at least one hydroxyaromatic compound as polymerization inhibitor, wherein the microencapsulated monomer mixture contains (a) 34 to 99.7% by weight of a monomer having one polymerizable C═C double bond, (b) 0.1 to 15% by weight of a crosslinking agent having at least 2 polymerizable C═C double bonds, (c) 0.2 to 1.0% by weight of at least one aliphatic peroxyester as polymerization initiator, and (d) 0 to 50% by weight of additives, the percentages being based on the sum of the components (a) to (c).

Abstract: A process for producing a vinyl chloride polymer is provided which includes the steps of: (A) suspension polymerizing vinyl chloride or a monomer mixture containing vinyl chloride, in an aqueous medium to obtain a polymer slurry; (B) stripping unreacted monomers remaining in the polymer slurry; and (C) subjecting the polymer slurry having passed through the step (B), to dehydration at a temperature of from 80° C. to 95° C., preferably within 60 minutes after the stripping. According to this process, the polymer cake obtained after the polymer slurry Is dehydrated can be made to have a greatly low water content. Hence the drying time in the drying step can be shortened to bring about an improvement in productivity and also to achieve a reduction of energy consumption in the drying step and consequently a reduction of production cost. Vinyl chloride polymer dried products having good anti-initial discoloration properties can be obtained.

Abstract: Disclosed are a resin composition for inhibiting polymerization of a vinyl compound, which includes a resin and 0.1 to 30% by weight based on the resin, of a polymerization inhibitor for the vinyl compound; a resin molding for inhibiting polymerization of a vinyl compound, and a packing for inhibiting polymerization of a vinyl compound in a distillation tower, the resin molding and packing each including this resin composition. Also disclosed are methods for inhibiting polymerization of a vinyl compound, which include contacting the vinyl compound with the resin composition; these methods include processes of inhibiting polymerization of a vinyl compound in a distillation tower, by contacting the vinyl compound in the distillation tower with packing therein which includes this resin composition.

Abstract: A particulate deactivator is used to pacify halogen-containing catalyst residues from a medium pressure solution polymerization process. The deactivator is added post-reactor preferably in the form of a suspension. The particulate deactivator may also be used in conjunction with a secondary, soluble deactivator.

Abstract: In a continuous gas-phase polymerization process for preparing ethylene and propene homopolymers and copolymers, in which ethylene, propene or a mixture of ethylene or propene and C3-C8-&agr;-monoolefins is polymerized in the polymerization zone of a gas-phase polymerization reactor at from 30 to 125° C. and a pressure of from 1 to 100 bar in the gas phase in a bed of finely divided polymer in the presence of a catalyst, where the reactor gas is circulated to remove the heat of polymerization, polymer deposits in the circulating gas line are prevented by metering a catalyst poison having a boiling point above the maximum temperature within the circulating gas line into this circulating gas line in at most such an amount that it does not significantly impair the productivity of the catalyst in the reactor.

Abstract: A process for preparing an aqueous emulsion with a narrow droplet size distribution of an oily material comprising one or more highly water insoluble substances, wherein the oily material is homogenized in a hydrophilic phase in which the oily material is more soluble than in water, but still so insoluble that an emulsion is formed by the homogenization, and the emulsion is subsequently diluted with a high proportion of water to form a stable emulsion of the oily material having the desired narrow size distribution. The stable emulsion may be mixed with an excess of a partly water soluble material which becomes absorbed by the droplets of the oily material. Said partly water soluble material may comprise a polymerizable monomer, and polymerization is subsequently effected to prepare a dispersion of polymer particles, and if desired, the polymer particles are recovered from said dispersion.

Abstract: The present invention is a free radical polymerization process for producing a branched polymer which comprises polymerizing a vinyl aromatic monomer in the presence of a molecular weight regulator which allows for the rapid production of high molecular weight and highly branched polymers without the formation of gels.

Abstract: Aqueous polymer dispersions are produced by polymerizing monoethylenically unsaturated monomers bearing acid groups in an acid, partially or totally neutralized form, optionally with other monomers that can be copolymnerized therewith in the presence of hydrophilized vegetable, animal and/or synthetic fats or oils. Also disclosed is a process for preparing the same, their use for preparing oil-in-water emulsions by admixture of another oil phase composed of vegetable, animal or synthetic oils and/of fats and/or non-self-emulsifying silicones, and their use in the field of wet currying of leather or pelts.

Abstract: Polymers of C.sub.2 -C.sub.12 -alkenes are prepared at from -50 to 300.degree. C. and from 0.5 to 3000 bar in the presence of a catalyst system by a process in which a compound of the general formula I ##STR1## where M.sup.1 is boron, aluminum, gallium, indium or thallium andR.sup.1 and R.sup.2 are each hydrogen, C.sub.1 -C.sub.10 -alkyl, C.sub.6 -C.sub.15 -aryl, alkylaryl or arylalkyl each having 1 to 10 carbon atoms in the alkyl radical and 6 to 20 carbon atoms in the aryl radical, or 5- to 7-membered cycloalkyl which in turn may carry C.sub.1 -C.sub.10 -alkyl as a substituent, or R.sup.1 and R.sup.2 together form a cyclic group, is added of 4 to 15 carbon atoms.

Abstract: Free radical polymerizations are immediately terminated by adding a phenothiazine-containing solution whose solvent comprises at least 50% of its weight of an N-alkylpyrrolidone.