Abstract: A process, particularly a gas phase fluidised bed process, for the production of polymers avoids formation of sheets or chunks within the reactor, without the need to use antistatic agents, which can reduce the activity of the catalyst or alter the characteristics of the yielded product. According to the invention, a device generates a corona discharge in the polymerisation reactor during the polymerisation process; an AC voltage difference is applied between the elements which constitute the discharging pair of the device.

Abstract: Methods and apparati have been developed for producing a suspension of predominately amorphous polymer particles, wherein the method includes thermally treating a suspension that includes crystalline or semi-crystalline polymer particles. The thermal treatment includes (a) heating a suspension of polymer particles of an appropriate size to a temperature effective to cause the polymer to become amorphous, and then (b) cooling the suspension of amorphous polymer particles below the melting point of the polymer at a rate effective to prevent substantial coalescence of the polymer particles. The method and apparati are effective for use with a variety of polymers having suitable crystallization parameters, although polyhydroxyalkanoate (PHA) polymers are preferred, particularly in an aqueous suspension medium. For PHA polymers, the polymer particles subjected to treatment preferably are of a size of less than 5 &mgr;m, or more preferably less than 1.5 &mgr;m in diameter.

Abstract: A method of emptying vessels containing dispersions, solutions or suspensions of polymers in which during the emptying process the liquid medium also used to take up the polymers into the dispersion, solution or suspension is passed into the space within the vessel that is not filled by the solution, dispersion or suspension, wherein the liquid medium used to take up the polymers into the dispersion, solution or suspension is introduced in vapor form.

Abstract: The present invention relates to apparatus for the semi-continuous polymerization of monomers with the use of a chain initiator. This apparatus is characterized in that it comprises a reactor (1) arranged with its axis substantially vertical and defining a lower, frustoconical part (III), an upper atonization part (I) and an intermediate part (II), the reactor (1) having monomer and initiator inlet apertures (8, 10, 20, 21) at least one outlet aperture (12), a recycling duct (15) connected at one end to the outlet aperture (12) and at the other end to the upper part (I) through at least one atomizer (9), and a stirrer (25). The apparatus according to the invention has the particular advantage of being usable for reactions with any type of chain initiator and catalyst, whether they are solid, liquid or in suspension.

Abstract: A process for polymerizing a vinyl chloride monomer wherein the vinyl chloride monomer is subjected to homopolymerization or (co)polymerization with a monomer copolymerizable with the vinyl chloride monomer in an aqueous solvent, comprising applying in advance a coating liquid containing a cocondensation product obtained by reacting either a phenothiazine derivative and an aldehyde or a phenothiazine derivative, a naphthol derivative and an aldehyde to give an initial condensation product and then reacting the initial product with a polyphenol, to an inner wall of a polymerization tank and parts of an apparatus in contact with the monomers during the polymerization process. The process makes it possible to apply the cocondensation product as an aqueous solution to, e.g., an inner wall of a polymerization tank; to quite effectively prevent polymer adhesion in, e.g.

Abstract: The present invention relates to a process and apparatus for the cleaning of crude tall oil soap. Crude soap floating on top of a layer of black liquor is cleaned with carbon dioxide, in a tall oil recovery system containing a cleaning vessel (T) for crude tall oil soap and black liquor. Said vessel has a carbon dioxide inlet (6) for introducing cleaning carbon dioxide into the soap. The cleaning vessel (T) is also provided with a black liquor separately from the cleaned soap. The cleaned soap may be acidified so as to provide tall oil.

Abstract: A method for producing optical rod-shaped graded-index polymer preform by making the composition of the preform near the core differ from the composition of the shell of the preform by polymerization with rotation of a mixture containing the starting substances, whereby a mixture comprising various monomers is rotated and that after achieving a distribution of the monomers, the polymerization is carried out with rotation of the mixture, or that a monomer and thermoplastic polymer-containing mixture, whereby said monomer is different from the monomer from which said polymer has been prepared, is rotated and that, after achieving a distribution of said monomer and polymer, the monomer present in said mixture is subsequently polymerized with rotation, in which both cases the rotation is carried out with a diameter dependent rotation velocity, represented by the following general equation: rpm>10,000 d.sup.-0.5 wherein: rpm=rotation velocity, revolutions per minute d=diameter of the preform (cm).

Abstract: Disclosed are a deposit suppressant composition for the internal surfaces of a polymerization reactor for polymerizing a vinyl monomer, including a polyhydric phenol sulfide compound having an average molecular weight of about 500 to 5000, as well as a method of polymerizing a vinyl monomer wherein prior to the polymerization, the internal surfaces of a polymerization reactor are coated with the deposit suppressant composition.

Abstract: There is provided a polymer scale deposition preventive agent, comprising an alkaline solution of a condensation product having a molecular weight of 500 to 1,000,000 obtained by condensing a dimer compound of 2,3-dihydroxynaphthalene with formaldehyde. By polymerizing vinyl chloride or a monomer mixture containing vinyl chloride in a polymerization vessel wherein a coating film made of said polymer scale deposition preventive agent has been formed on the inner wall surface and the like, polymer scale is effectively prevented from depositing not only on an agitation apparatus but also on areas near the interface between a gas phase and a liquid phase, which prevention of the polymer scale deposition is conventionally difficult. Thus, a vinyl chloride polymer can be obtained which contains colored foreign matters, fish eyes, etc. in small amounts and is small in initial discoloration and is good in quality.

Abstract: Disclosed is a method of inhibiting the formation of scale on reactor surfaces in contact with a polymerizing vinyl monomer comprising contacting said monomer with a terpolymer which comprises the condensation reaction product of(A) an aromatic compound that contains the group ##STR1## where Q is OR or SR and R is hydrogen, alkyl from C.sub.1 to C.sub.15, or aryl, alkaryl, or aralkyl from C.sub.6 to C.sub.15 :(B) about 0.1 to about 10 moles of a carbonyl compound per mole of said aromatic compound; and(C) about 0.1 to about 10 moles of a thiourea per mole of said aromatic compound.

Abstract: There is provided a process for drying a fluidized reactor system comprising introducing a boiling point depressing agent into said system optionally while heating said system.

Abstract: A method for continuously producing a polyester by continuously melt-polymerizing a raw material consisting of a dicarboxylic acid component composed of mainly an aromatic dicarboxylic acid and containing an alicyclic dicarboxylic acid or an aliphatic dicarboxylic acid, or their ester-forming derivatives with a diol component, characterized in that said diol component as a distillate in the polycondensation reaction, including an adhering material, is condensed, said adhering material is separated centrifugally, and then the residual diol component, after distillation, is supplied to an esterification reaction or an ester interchange reaction.

Abstract: The invention comprises a novel process for producing an anti-scaler coating for monomer polymerization reactors comprising mixing hydroxymethansulphincal acid with 1-naphthol. The invention also comprises an anti-scaling product obtained by this novel process.

Abstract: The object of the invention is to provide a liquid anti-scaler for coating polymerizing reactors obtained by a condensation reaction of naphthol with an aldehydic cross-linking product, wherein the cross-linking product is the reaction product of hydrosulfite and formaldehyde. It contains hydrosulfite and/or radical bisulfites and/or bisulfite. The condensate is made in such a way that in the absence of oxygen, it is in the form of liquid of clear transparent color.

Abstract: An improved process for producing a polymer by polymerizing a monomer having an ethylenic double bond in a polymerization vessel having a polymer scale preventive coating film on its inner wall surfaces, etc. is provided. The coating film is formed by coating a first coating liquid containing a compound selected from the group consisting of an aromatic compound having 5 or more conjugated .pi. bonds and a heterocyclic compound having 5 or more conjugated .pi. bonds, and then coating a second coating liquid on the first layer. The first and second coating liquids are applied by means of steam as a carrier. The second layer has a surface having a contact angle to water of less than 60.degree. after its surface has been brought into contact with a solution of mixture of water and a vinyl chloride monomer in a weight ratio of 1:1, at 50.degree. C. for 1 hour.

Abstract: In a process for producing vinyl chloride polymers including polymerization of vinyl chloride or a monomer mixture containing it in an aqueous medium using a polymerization initiator, the polymerization is carried out in the presence of a chelating agent, The chelating agent is capable of chelating iron (II) and iron (III). This process makes it possible to prevent polymer scales from adhering to, e.g. baffle surfaces facing inner walls of the polymerization vessel, which has been hitherto difficult to do so, and less cause initial discoloration of polymer products to improve quality. It is more effective to use a polymerization vessel previously provided with coating films of a polymer scale preventive agent on the inner walls of the polymerization vessel and the other portions with which monomers come into contact in the course of polymerization.

Abstract: Disclosed is a method of inhibiting the formation of scale on reactor surfaces in contact with a polymerizing vinyl monomer. The reactor surfaces are contacted with a composition that contains, as a scale reducing agent, an acidic hydrazone condensate or a salt thereof. The scale reducing agent can be added to the polymerizing monomer or it can be placed in a composition containing a surfactant and an inorganic binder and the composition can be applied to the reactor surfaces or added to the monomer.

Abstract: An apparatus for converting PET into polyester polyols including a reactor vessel having an interior volume and an inlet and an outlet, a rotation device connected to the reactor vessel for rotating the reactor vessel, and a heater system interactive with the interior of the reactor vessel so as to elevate a temperature of the interior volume of the reactor vessel to at least 175.degree. C. The reactor vessel extends in a generally horizontal orientation. The rotation device includes a roll ring affixed circumferentially around the reactor vessel, a drive roller engaging the roll ring and a motor connected to the drive roller for drivingly rotating the drive roller and the associated roll ring. The heater system includes a plurality of heating pipes extending through the interior volume of the reactor vessel and a heated fluid injector connected to the plurality of heating pipes for passing a heated fluid into the pipes.

Abstract: According to the invention, there are provided a novel process for preparing an anti-scaling coating on the walls of a polymerization vessel by using aromatic compounds reacted with sodium hydroxymethanesulphinate, and an anti-scaling coating obtained by this novel process.

Abstract: This invention relates to a process for producing an anti-scaler product for coating polymerization reactors comprising condensing a naphthol with an aldehydic cross-linking agent, wherein the cross-linking agent is the reaction product of an aldehyde and a hydrosulphite.

Abstract: A process is provided for the polymerization of vinyl chloride in a closed mode. According to the process, oxygen is caused to exist in a polymerizer, which is coated with an anti-fouling agent, during an operation in which the polymerization is repeated. The process according to this invention has made it possible to fully exhibit effects of the anti-fouling. This has in turn made it possible to achieve polymerization of vinyl chloride in the closed mode, leading to an improvement in productivity.

Abstract: A method for the homopolymerization or copolymerization of vinyl chloride, wherein the inner wall of the polymerizer and the like are prevented from being fouled with the resulting polymer by applying a coating fluid containing the oxidative polymerization product of a specific phenolic monomer to the surface of the inner wall of the polymerizer and the like, as well as an anti-fouling agent used for this purpose. The method of this invention can very effectively prevent the polymerizer and the like from being fouled with the resulting polymer without affecting the polymerization rate and various properties of the product. Consequently, the necessity of performing the operation for removal of the deposited polymer after completion of each polymerization cycle is eliminated, thus making it possible to achieve closed polymerization requiring no manhole opening after each polymerization cycle which is becoming increasingly popular in recent years.

Abstract: A polymer scale deposition preventive agent comprising (a) an aromatic compound having at least eight conjugated .pi. bonds and having a molecular weight of 1,000 or more, and (b) a polyalkylene oxide having a weight-average molecular weight of 2,000 or more, wherein the weight ratio of the component (a) to the component (b) is 100/500 to 100/1, can prevent surely the deposition of polymer scale even in a polymerization system containing a monomer, such as styrene, acrylic acid esters or acrylonitrile, which has a high solvency for a coating film consisting of the conventional polymer scale deposition preventive agent.

Abstract: In a novel method of homo- or copolymerization of vinyl chloride, a specified coating agent is applied on the surfaces of the portions which will become into contact with the vinyl chloride monomer during the polymerization process. The coating agent is in a form of an aqueous solution of a modified condensation product of phenol and aldehyde, the pH of the solution being adjusted in a range that the product is dissolved at an ambient temperature upon coating of the solution and separates out of the solution upon being heated on the surfaces. The wall surface of the polymerization tank and the like is then coated with a thin film of the coating agent having a uniform thickness and being strongly adhered to the wall surface, thereby providing an excellent effect of preventing adhesion of the product polymer to the wall surface.

Abstract: A process is provided for preparing a polymer from an ethylenically unsaturated monomer, wherein the process provides reduced polymer scale deposition both in the liquid-phase region of the polymer vessel and on areas around the interface between the gas phase and the liquid phase, the process involving the use of a polymer vessel having a coating on at least its inner surfaces of a polymer scale preventive film prepared from a polymer scale preventive agent of a salt, either alkali metal, ammonium or both, of a sulfonation product of a condensate prepared from (A) an aromatic amine compound and (B) an aldehyde.

Abstract: A polymer scale preventive agent for use in polymerization of a monomer having an ethylenically unsaturated double bond, comprising an alkaline liquid containing a condensation product of: (A) at least one compound selected from the group consisting of azo compounds having at least two amino groups and azoxy compounds having at least two amino groups, and (B) a quirtone compound, is disclosed. Also disclosed is a process for producing a polymer, which comprises polymerizing the monomer in a polymerization vessel having a coating on its inner wall, whereby deposition of polymer scale is prevented, the coating having been formed by applying the scale preventive agent and drying the applied agent.

Abstract: A polymer scale preventive agent for use in polymerization of a monomer having an ethylenically unsaturated double bond, comprising an alkaline solution containing (A) a condensation product having a molecular weight of 400 to 50,000 obtained by condensing a quinone compound. This agent is applied to the inner wall surfaces of a polymerization vessel, and dried to form a coating. Such a vessel is effective in preventing polymer scale deposition, not only on the areas located in the liquid-phase region but also on the areas around the interface between the gas and liquid phases in the vessel, and is useful in producing a polymer that shows few fish eyes and good whiteness when formed into sheets or the like.

Abstract: In a novel method of homo- or copolymerization of vinyl chloride, a specified coating agent is applied on the surfaces of the portions which will become into contact with the vinyl chloride monomer during the polymerization process. The coating agent is in a form of an aqueous solution of a modified condensation product of phenol and aldehyde, the pH of the solution being adjusted in a range that the product is dissolved at an ambient temperature upon coating of the solution and separates out of the solution upon being heated on the surfaces. The wall surface of the polymerization tank and the like is then coated with a thin film of the coating agent having a uniform thickness and being strongly adhered to the wall surface, thereby providing an excellent effect of preventing adhesion of the product polymer to the wall surface.

Abstract: In a novel method of homo- or copolymerization of vinyl chloride, a specified coating agent is applied on the surfaces of the portions which will become into contact with the vinyl chloride monomer during the polymerization process. The coating agent is in a form of an aqueous solution of a modified condensation product of phenol and aldehyde, the pH of the solution being adjusted in a range that the product is dissolved at an ambient temperature upon coating of the solution and separates out of the solution upon being heated on the surfaces. The wall surface of the polymerization tank and the like is then coated with a thin film of the coating agent having a uniform thickness and being strongly adhered to the wall surface, thereby providing an excellent effect of preventing adhesion of the product polymer to the wall surface.

Abstract: A one-step for making a lightly-crosslinked polyvinylpyrrolidone hydrogel by polymerizing vinyl pyrrolidone in water in the presence of a suitable crosslinker such as 1-vinyl-3(E)-ethylidene pyrrolidone and a free radical initiator under initial agitation conditions sufficient to overcome the inertia of the polymer when formed.

Abstract: A polymer scale preventive agent for use in polymerization of a monomer having an ethylenically unsaturated double bond, comprising an alkaline solution containing (A) a condensation product of (A-1) a hydroxynaphthalene compound and (A-2) an aldehyde compound, and (B) an inorganic colloid. This agent is used for forming a coating on the inner wall, etc. of a polymerization vessel. Such a vessel is effective in preventing polymer scale deposition, not only in the liquid-phase region but also in the vicinity of the interface between the gas and liquid phases in the vessel, and useful in producing a polymer that shows very few fish eyes and good whiteness when formed into sheets or the like.

Abstract: This process is a process of producing a vinyl chloride polymer by suspension polymerization of vinyl chloride or a mixture of vinyl monomers mainly made up of vinyl chloride in an aqueous medium in the presence of an oil-soluble polymerization initiator, wherein, as said oil-soluble polymerization initiator, (A) an organic peroxide such that a 10-hour half-life period temperature of a solution containing 0.1 mol of the organic peroxide per liter of benzene is 30.degree. to 50.degree. C. and the organic peroxide does not, in its structure, contain a benzene ring or an alkoxy group, and (B) 3-hydroxy-1,1-dimethylbutyl peroxyneodecanoate are used in combination. The polymerization vessel used is preferably coated with a polymer scale preventive agent.

Abstract: A polymer scale deposition preventive agent for use in polymerization of a monomer having an ethylenically unsaturated double bond, comprising an aluminum fluoride.According to the present invention, deposition of polymer scale in a polymerization vessel can be effectively prevented, not only on the areas in the liquid-phase region but also on the areas around the interface between the gas phase and the liquid phase. In addition, the polymer obtained can be formed into products which have very few fish eyes.The application of the present invention to polymerization makes it unnecessary to remove polymer scale for every polymerization run, thereby improving productivity.

Abstract: A process for the production of a vinyl chloride polymer by suspension polymerization of vinyl chloride, optionally in the presence of other vinyl monomers, in an aqueous medium, in the presence of an oil-soluble polymerization initiator, which is a combination of (A) t-butyl peroxyneoheptanoate, and (B) a peresteric peroxide, such as t-butyl peroxyneodecanoate, other than the above component (A), in a polymerization vessel having at its inner wall surface, a polymer scale deposition preventative coating, which is formed by applying an alkaline coating liquid, of (a) at least one condensation product of a quinone compound and a condensate of a quinone compound with an amino group containing diphenyl compound, and (b) at least one of the substances, a water-soluble polymer compound, an inorganic colloid or an alkali metal silicate, followed by drying the above coating.

Abstract: A method for producing an aromatic polycarbonate comprises feeding to a feeding zone (having a foraminous plate) at least one polymerizing material selected from the group consisting of a) a molten monomer mixture of an aromatic dihydroxy compound and a diaryl carbonate, and b) a molten prepolymer obtained by a process comprising reacting an aromatic dihydroxy compound with a diaryl carbonate, and allowing the polymerizing material to pass downwardly through the foraminous plate and fall along and in contact with a wire through a wire-wetting fall polymerization reaction zone, thereby effecting polymerization of the polymerizing material during the wire-wetting fall thereof. Colorless and high quality aromatic polycarbonates are thus stably produced at a high polymerization rate for a prolonged period of time, using an apparatus which has excellent sealing properties under high vacuum and maintenance of which is easy.

Abstract: A polymer scale preventive agent for use in polymerization of a monomer having an ethylenically unsaturated double bond, comprising an alkaline solution containing: (A) a condensation product of (A-1) a condensate of acetone with a hydroxybenzene compound having at least two hydroxyl groups, and (A-2) an aldehyde compound; (B) an inorganic colloid; and (C) a water-soluble polymeric compound. This agent is used for forming a coating on the inner wall, etc. of a polymerization vessel. Such a vessel is effective in preventing polymer scale deposition, not only on the areas in the liquid-phase region but also on the areas around the interface between the gas and liquid phases in the vessel, and useful in producing a polymer that shows very few fish eyes and good whiteness when formed into sheets or the like.

Abstract: The present invention relates to an acid catalyzed thermal polycondensation process for producing amino acid polymers. More specifically, amino acid polymers are produced by thermally condensing a mixture of one or more amino acids and optionally one or more polyfunctional monomers, using an acid catalyst, while maintaining an intimate admixture. Processing techniques useful for maintaining an intimate admixture include adding to the mixture one or more processing aids, using mechanical means, and combinations thereof. The amino acid polymers produced by this process are useful as cleaning and detergent additives; fertilizer and pesticide additives; personal care product additives; dispersants for inorganic particulates, aqueous emulsions, and drilling muds; and water treatment and oil production operation additives as corrosion and scale inhibitors.

Abstract: The present invention relates to an acid catalyzed thermal polycondensation process for producing amino acid polymers. More specifically, amino acid polymers are produced by thermally condensing a mixture of one or more amino acids and optionally one or more polyfunctional monomers, using an acid catalyst, while maintaining an intimate admixture. Processing techniques useful for maintaining an intimate admixture include adding to the mixture one or more processing aids, using mechanical means, and combinations thereof. The amino acid polymers produced by this process are useful as cleaning and detergent additives; fertilizer and pesticide additives; personal care product additives; dispersants for inorganic particulates, aqueous emulsions, and drilling muds; and water treatment and oil production operation additives as corrosion and scale inhibitors.

Abstract: A method for passivating internal surfaces of a reactor system during start-up and shutdown of an alpha olefin polymerization or copolymerization reaction by adding a passivation agent such as a dialkyl zinc compound, an alcohol, or an epoxide, to the reactor prior to exposing the internal reactor surfaces to air or moisture before reaction initiation and/or after reaction ceases.

Abstract: A polycarbonate is produced by transesterification from a dihydroxy compound such as 2,2-bis(4-hydroxyphenyl)propane and a diester of carbonic acid such as bisphenyl carbonate in a reactor made of stainless steel and treated by electropolishing or acid pickling or buffed on a surface part thereof which contacts the reactants. As the transesterification catalyst, (a) a nitrogen-containing, electron-donating compound and (b) a nitrogen-containing, electron-donating compound and an alkali metal compound or an alkaline earth metal compound are preferably used.

Abstract: A polymer scale deposition preventive agent for use in polymerization of a monomer having an ethylenically unsaturated double bond, comprising an alkaline solution containing a condensation product of (A) an anthraquinone compound having at least two amino groups and (B) at least one compound selected from the group consisting of benzoquinone compounds and naphthoquinone compounds. When the monomer is polymerized in a polymerization vessel having a coating formed by applying the aforementioned preventive agent to inner wall surfaces followed by drying, polymer scale can be effectively prevented from being deposited not only on the areas located in the liquid-phase region but also on the areas around the interface between the gas and liquid phases in the polymerization vessel. When an obtained polymer is formed into a sheet or the like, it is possible to obtain a formed product having few fish eyes and low initial coloration.

Abstract: In the polymerization of olefins using a catalyst comprising an organoaluminum compound and solid catalyst components containing titanium and/or vanadium; and magnesium in a vapor phase fluidized bed, the formation of sheet-like polymer and other abnormal conditions in the initial stage of the polymerization are avoided by means of previous drying of the reactor by feeding an organoaluminum compound prior to the feeding of seed polymer, the quantity of said organoaluminum compound being calculated by the following equation (I):A=k.multidot.V.sup. 2/3 (I)wherein A is the feed quantity (mol) of the organoaluminum compound, k is a coefficient (mol/m.sup.2) in the range from 0.15 to 4, and V is the volume (m.sup.3) of the whole system including gas circulation pipings.

Abstract: A process for preparing an aromatic polycarbonate resin from an aromatic dihydroxy compound and a carbonate diester by transesterification in the presence of a transesterification catalyst comprising; reacting a purified carbonate diester with an aromatic dihydroxy compound in the presence of a transesterification catalyst to form a polycarbonate prepolymer; said carbonate diester containing benzophenone and benzoate ester derivatives having a molecular weight of less than 1,000, each in an amount of 100 ppm or less, said polycarbonate prepolymer having a viscosity average molecular weight of 5,000 to 20,000 at a temperature of 140.degree. to 280.degree. C., the reaction pressure being from 0.1 Torr to normal pressure; polymerizing said prepolymer at a temperature of 240.degree. to 350.degree. C. in a lateral, bi-axial, self-cleaning reactor to obtain an aromatic polycarbonate resin having a viscosity average molecular weight of 15,000 to 60,000.

Abstract: The polymer scale preventive agent comprises an alkaline solution containing (A) an condensation product of (A-1) a hydroxybiphenyl compound with (A-2) an aldehyde compound, (B) a reaction stopper, and (C) an inorganic colloid and is used for polymerization of a monomer having an ethylenically unsaturated double bond. The process of producing the polymer comprises polymerizing the monomer in a polymerization vessel having a coating film on its inner wall surfaces, whereby polymer scale is prevented from being deposited, wherein said coating film is formed by applying, on said inner wall surfaces, said alkaline solution, followed by drying. According to the invention, deposition of polymer scale can be effectively prevented not only on the areas in the liquid phase but also at and in the vicinity of the interface between the gas and liquid phases in a polymerization vessel.

Abstract: A process for producing a polymer of a monomer having an ethylenically unsaturated double bond is described, wherein the monomer is polymerized in a polymerization vessel having a coating on its inner wall surfaces of a specific three-component polymer scale preventive agent, these three components are a naphthoquinone dimer, a water soluble polymer, and an inorganic colloid, whereby polymer scale is prevented from being deposited on the inner wall surfaces of the polymerization vessel.

Abstract: A polymer scale preventive process for use in polymerization of a monomer having an ethylenically unsaturated double bond, comprising (A) a water-soluble basic polysaccharide and (B) a phenothiazine. The process is used for forming a coating on the inner wall, etc. of a polymerization vessel, and highly safe for operators. Deposition of polymer scale can be effectively prevented, and polymeric product with high whiteness or a low initial coloration is obtained.

Abstract: A polymer scale preventive process for use in polymerization of a monomer having an ethylenically unsaturated double bond, comprising an alkaline solution containing a condensation product of (A) an aromatic amine compound having at least two amino groups and (B) an aromatic tetracarboxylic acid anhydride. This process is used for forming a coating on the inner wall, etc. of a polymerization vessel. Such a vessel is effective in preventing polymer scale deposition and useful in producing a polymer that shows very few fish eyes and good whiteness when formed into sheets or the like.

Abstract: A polymer scale preventive process for use in polymerization of a monomer having an ethylenically unsaturated double bond, comprising an alkaline solution containing (A) a condensation product of (A-1) an aromatic compound having at least two amino groups with (A-2) an aromatic tetracarboxylic acid anhydride, and (B) at least one member selected from the group consisting of (B-1) a water-soluble polymeric compound and (B-2) an inorganic colloid. The scale preventive process is low in virulence or the like, and high in safety. The process is used for forming a coating on inner wall surfaces of a polymerization vessel. Where such a polymerization vessel is used to carry out the polymerization, polymer scale deposition can be effectively prevented, not only on areas in the liquid-phase region but on areas around the gas-liquid interface in the vessel, and the resulting polymeric product shows few fish eyes and good whiteness when formed into sheets or the like.

Abstract: A method for the rapid esterification of dicarboxylic acids or the transesterification of lower alkyl carboxylic acid diesters with diols is disclosed. The method includes recycling of evaporated unreacted starting materials and can be carried out at elevated pressures. The resulting esterification or transesterification products can then be polymerized into polyesters, for example by a thin film polymerization method.

Abstract: A polymer scale preventive process for use in polymerization of a monomer having an ethylenically unsaturated double bond, comprising an alkaline solution containing a condensation product of (A) an aromatic amine compound and (B) a quinone compound. This process is used for forming a coating on the inner wall, etc. of a polymerization vessel. Such a vessel is effective in preventing polymer scale deposition and useful in producing a polymer that shows very few fish eyes and good whiteness when formed into sheets or the like.