Abstract: Vinyl chloride or a monomer mixture containing it transported over a long distance or stored for a long period usually contains a polymerization inhibitor and Fe ions. If this kind of vinyl chloride or monomer mixture is polymerized, stirring torque during the polymerization increases, and heat removal by the cooling jacket of a polymerization vessel tends to become insufficient, making the polymer quality subject to bad influences. In the present invention, a hydroxycarboxylic acid compound is added to the polymerization mixture in an amount of 50-1000 ppm relative to the monomer or monomer mixture. As a result, an increase in stirring torque during polymerization is suppressed, and heat removal by the cooling jacket of the polymerization vessel can be performed effectively, making it possible to obtain vinyl chloride of good quality.

Abstract: An easy adhesion film for a transparent conductive thin film comprises a transparent polymer film and an easy adhesion layer formed on the transparent polymer film, wherein the easy adhesion layer comprises at least an ionizing radiation curable resin binder, a (meth)acrylate copolymer binder and polymethyl methacrylate resin particles. The easy adhesion film has high durability, transparency and anti-Newton ring property when provided with a transparent conductive thin film.

Abstract: A suspending agent-containing slurry is disclosed which comprises a dispersant and a particulate suspending agent having a particle size distribution in which the particle diameter at weight-cumulative 95%, from the minimum particle size, is 1 &mgr;m or smaller. A method for efficiently producing the suspending agent-containing slurry is also disclosed. A process for suspension polymerization by use of the suspending agent-containing slurry is further disclosed. The slurry not only has such an excellent suspending ability in suspension polymerization that it enables the production of vinyl polymer beads having a narrow bead size distribution, but also is capable of retaining this ability over long and of exhibiting the same ability even when it has a high concentration. The suspension polymerization process enables vinyl polymer beads having a narrow bead size distribution to be produced efficiently due to the use of the slurry.

Abstract: The invention relates to aqueous emulsions of peroxyesters comprising an anti-freeze agent, a polyvinyl acetate with a degree of hydrolysis between 45 and 68%, and a non-ionic surfactant with an HLB value greater than 16 selected from alkylene oxide block-copolymers, ethoxylated fatty alcohols, and ethoxylated fatty acids. The emulsions are safe, storage stable, and generally applicable.

Abstract: The present invention is a process for producing a polyvinyl chloride paste blending resin comprising polymerizing a vinyl chloride-based monomer by a suspension polymerization in an aqueous medium, wherein as a suspending agent, both (A) and (B) are used in a mixing weight ratio (A)/(B) of 99/1 to 50/50, and a total amount of said (A) and said (B) is 0.1 to 1.0 part by weight based on 100 parts by weight of the vinyl chloride-based monomer, said (A) being a partially hydrolyzed water-soluble poly(vinyl alcohol) having a viscosity at 20° C. of 4% aqueous solution by weight of 20 to 110 cps and the degree of hydrolysis of 86 to 99 mol %, and said (B) being a partially hydrolyzed water-soluble poly (vinyl alcohol) having a viscosity at 20° C. of 4% aqueous solution by weight of 5 to 10 cps and the degree of hydrolysis of 70 to 80 mol %.

Abstract: Polyvinyl ester dispersions which can be employed as binders in building materials, preferably in the form of redispersible plastics powders, are obtained by polymerization of at least one vinyl ester and optionally other monomers which can be copolymerized with vinyl ester, by use of water-soluble cationic azo initiator.

Abstract: Natural cyclic polyalcohols such as polyfructoses and, dehydration products of sugar alcohols can be used for stabilising thermoplastic polymers, at a ratio of 0.001-5 phr of polyol with respect to the polymer. The cyclic polyol is in particular inulin or sorbitan. The polymer to be stabilised is in particular PVC, PE, PP or a halogenated rubber.

Abstract: A method for producing protective-colloid-stabilized polymers in the form of their aqueous polymer dispersions or in the form of powders which can be re-dispersed in water, wherein one or several monomers from the group made up of vinyl aromatics, 1.3 dienes, acrylic acid esters and methacrylic acid esters of alcohols with 1 to 15 C-atoms are polymerized in the presence of a combination of protective colloids consisting of one or several protective colloids from the group of hydrophobically modified, partly saponified polyvinyl esters which produce a surface tension of ≦40 mN/m as a 2% aqueous solution, and one or several protective colloids which produce a surface tension of >40 mN/m as a 2% aqueous solution.

Abstract: The present invention relates to a process for preparing polymer powders from aqueous polymer dispersions in which the dispersed polymer P comprises in copolymerized form: i) at least one vinylaromatic monomer (a), ii) 1,3-butadiene as monomer (b), and iii) one or more monomers (c) different than the monomers (a) and (b), which comprises drying the aqueous polymer dispersion in the presence of polyvinyl alcohol as drying agent. The present invention also relates to the polymer powders obtainable by this process and to the use of these polymer powders as binders in paints, varnishes and coating compositions generally, in adhesives, and for modifying mineral construction materials. The present invention also relates to mineral construction materials in the form of dry formulations comprising the polymer powders of the invention.

Abstract: A continuous emulsion polymerization process consisting of multiple stirred-tanks in series is used to produce a broad particle-size distribution for vinyl acetate-based emulsions utilizing polyvinyl alcohol as a protective colloid. When low-molecular-weight grades of PVOH and a continuous process are employed, a high-solids emulsion can be produced. This process eliminates the need for a co-surfactant, which is required to make similar high-solids emulsions via a batch process.

Abstract: A graft resin having a structure of the formula (1) and having a number average molecular weight of 2,000 to 50,000, has excellent low-temperature moldability and exhibits an excellent shelf life against softening when stored at high temperatures, and an electrostatic charge developing toner containing the above graft resin as a binder exhibits excellent low-temperature fixing properties, developability and transferability without impairing the shelf life.

Abstract: A particulate polymer P having an average particle diameter d50 of from 0.1 to 50 &mgr;m is prepared by a process in which an emulsion E is prepared from one or more monomers M, which are polymerizable by free radical polymerization to give the polymer P, water, and at least one protective colloid PC by the action of high shear forces, and the emulsion E is subjected to polymerization in a reactor with the use of a free radical polymerization initiator RI wherein, based on the emulsion E, not more than 75% by weight of the emulsion E (initially taken portion of E) are initially taken in the reactor at the beginning of the polymerization and at least 25% by weight of the emulsion E (feed portion of E) are not fed to the reactor until after the beginning of the polymerization.

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: The present invention is a process for producing a polyvinyl chloride paste blending resin comprising polymerizing a vinyl chloride-based monomer by a suspension polymerization in an aqueous medium, wherein as a suspending agent, both (A) and (B) are used in a mixing weight ratio (A)/(B) of 99/1 to 50/50, and a total amount of said (A) and said (B) is 0.1 to 1.0 part by weight based on 100 parts by weight of the vinyl chloride-based monomer, said (A) being a partially hydrolyzed water-soluble poly(vinyl alcohol) having a viscosity at 20.degree. C. of 4% aqueous solution by weight of 20 to 110 cps and the degree of hydrolysis of 86 to 99 mol %, and said (B) being a partially hydrolyzed water-soluble poly(vinyl alcohol) having a viscosity at 20.degree. C. of 4% aqueous solution by weight of 5 to 10 cps and the degree of hydrolysis of 70 to 80 mol %.

Abstract: A polymeric material comprising at least first and second polymer parts, which first part has a number average molecular weight higher than that of the second part and which first and second polymer parts each comprise a respective polymer part derived from at least one ethylenically unsaturated monomer, is prepared by a process which comprises the steps of (1) preparing, by aqueous suspension polymerisation the first, higher molecular weight polymer part in the presence of a free radical initiator, but in the absence of a chain transfer agent to form a suspension of the first, higher molecular weight part and thereafter (2) preparing by aqueous suspension polymerisation the second, lower molecular weight part, which preparation step (2) is carried out in the presence of the suspension of the first, higher molecular weight part, a free radical initiator and a catalytic chain transfer agent (CCTA).

Abstract: A process for the preparation of aqueous polymer dispersions of low viscosity with polymer volume concentrations of at least 50% by volume, based on the polymer dispersion, by free-radical emulsion polymerization of ethylenically unsaturated monomers, with the exception of vinyl halides and vinylidene halides, in the presence of at least one initiator and at least one initial polymer involves emulsifying the major proportion of the monomers in an aqueous dispersion of the initial polymer and supplying this emulsion continuously to the polymerization reaction.

Abstract: There is disclosed a synthetic resin powder comprising a polymer made from an ethylenically unsaturated monomer or a diolefinic monomer and a polyvinyl alcohol chemically bonded through a sulfide bond at an end thereof to the surface of a particle of the polymer. Although the synthetic resin powder of the present invention can be in the form of powder during transportation, it can easily be dispersed in water by adding water thereto under stirring, because it is excellent in dispersibility in water and blocking resistance. The synthetic resin powder is excellent also in film forming properties, and thus can preferably be used as an admixture for a mortar, etc.

Abstract: A dispersing stabilizer suitable for suspension polymerization of vinyl chloride or a monomer mixture mainly composed of vinyl chloride which can be used in a hot water charging polymerization process without any problems, and which can produce vinyl chloride homopolymer or copolymers having a good porosity, a large bulk density, a very low content of coarse particles and good physical properties, the dispersing stabilizer comprising a polyvinyl alcohol having a degree of hydrolysis of 75 to 85% by mole, an absorbance of not less than 0.1 measured at a wavelength of 280 m.mu.with respect to the 0.1% by weight aqueous solution, a content of carboxyl group of 0.01 to 0.15% by mole and a cloud point of not less than 50.degree. C. measured with respect to the 0.

Abstract: A process for the preparation of an aqueous solution or dispersion containing a cationic polymer, which comprises the steps of: polymerizing a monomer including an N-vinylcarboxylic acid amide represented by the general formula CH.sub.2 .dbd.CHNHCOR, wherein R represents a hydrogen atom or methyl group, in an aqueous medium in the presence of either or both of a polyethylene glycol and polypropylene glycol; and then modifying the resulting polymer with an acid or base. Furthermore, an aqueous composition containing a cationic polymer, which comprises (A) a modified N-vinylcarboxylic acid amide polymer, (B) either or both of a polyethylene glycol and polypropylene glycol, and (C) water is disclosed.

Abstract: In a process for the polymerization of aqueous ethylene vinyl acetate emulsions wherein the polymerization is carried out in the presence of a stabilizing system comprising polyvinyl alcohol and a surfactant, the improvement which comprises using a stabilizing system consisting essentially of 2 to 8% polyvinyl alcohol and 0.25 to 4% of at least one surface-active compound comprising the addition products of 50 to 70 moles of ethylene oxide adducted to straight-chained or branch-chained alkanols or alkylphenols containing 6 to 22 carbon atoms in the alkyl group and having an HLB value equal to or greater than 18.0, the amounts being based on total vinyl acetate.

Abstract: The present invention provides adhesive compositions which include free radical polymerizable compounds and a redox catalyst system to accelerate polymerization thereof. The redox catalyst includes an aniline derivative substituted in the para position by halogen as an accelerator. The use of para-halogenated aniline derivatives as an accelerator in the cure of free radical polymerizable compounds results in good bond strength and greatly improved surface cure of the adhesive composition.

Abstract: Heterogeneous, solvent- and plasticizer-free polyvinyl ester dispersions which are stabilized by protective colloids and which have a minimum filming temperature of below 10.degree. C. are disclosed. These dispersions are made of a mixture of(a) a homopolymer or copolymer A having a glass transition temperature of above 20.degree. C., whereby homopolymer or copolymer A includes(i) from 85 to 100% by weight of at least one vinyl ester of carboxylic acids having 1 to 18 carbon atoms;(ii) from 0 to 5% by weight of at least one .alpha., .beta.-unsaturated carboxylic acid;(iii) from 0 to 5% by weight of at least one mono-olefinically unsaturated compound (a3) having at least one amino or amido group, and(iv) from 0 to 5% by weight of at least one polyethylenically unsaturated monomer, and(b) a copolymer B having a glass transition temperature of below 20.degree. C.

Abstract: Thermoplastic or thermosetting resin particles having a narrow particle size distribution are produced by suspending a liquid resinous composition in an aqueous solution of an anionic or cationic polyelectrolyte as primary particles of oil droplets, adjustion the suspension at a pH at which the polyelectrolyte is insolubilized to agglomerate into secondary particles of larger particle size, and allowing the secondary particles in the suspension to solidify.

Abstract: An azo group-containing high molecular weight compound including --COHN--, an ester linkage, or an amido linkage and a monomer units of 10 to 1000 derived from .alpha.,.beta.-ethylenically unsaturated monomer is effective for producing a block copolymer having two or more polymer segments different in structure by one-step reaction.

Abstract: The production process includes starting suspension polymerization of vinyl chloride-based monomer in a polymerization vessel in the presence of a particular combination of suspending agents; and, at the time when a polymerization conversion has reached 5 to 60%, further adding to the reaction mixture a partially saponified polyvinyl alcohol having an average polymerization degree of 1,500 to 4,000 and a saponification degree of 75 to 98 mole %, wherein a carboxylic acid ester of polyhydric alcohol is further added to at least one one selected from a content inside the polymerization vessel prior to the start of the polymerization, a content inside the polymerization vessel during the polymerization, and the resulting polymer. According to the process, there is obtained a vinyl chloride polymer having a large bulk specific gravity and a fast gelation rate, and from the polymer, a formed part small in both the number of fish eyes and the amount of residual monomer can be obtained.

Abstract: There is described a novel process of polymerizing 4-vinyl pyridine monomer in an aqueous polymerization system which comprises preparing an aqueous solution of polyvinyl alcohol, and contacting said aqueous solution of a polyvinyl alcohol with less than about 10% by weight of 4-vinyl pyridine monomer and a water-soluble initiator capable of decomposing to give free radicals.The resultant dispersion of the novel polymerization process comprises a homogeneous, i.e., weight average molecular weight and particle size, poly-4-vinylpyridine, with no appreciable residual 4-vinyl pyridine monomer.The resultant dispersion may be used to coat image- and ink-receiving layers of image-recording materials and ink jet recording sheets, respectively.

Abstract: There is disclosed a process for producing a vinyl resin by suspension polymerization of a vinyl compound in the presence of a suspending agent (A) which comprises using a polymerization vessel equipped with a reflux condenser and adding a polyvinyl alcohol (B) having a degree of hydrolysis of at most 85 mol % in an amount of 0.001 to 0.5 part by weight based on 100 parts by weight of said vinyl compound when a polymerization conversion is in the range of 30 to 90%.According to the present invention, there is provided a process for producing a vinyl resin having a high bulk density, which is excellent in anti-foaming effect against the dry foam being generated in the middle to latter period of the suspension polymerization in a polymerization vessel equipped with a reflux condenser which is excellent in productivity.

Abstract: Water-insoluble polymers are prepared by free radical polymerization of ethylenically unsaturated monomers by a process in which the polymerization is carried out in an aqueous gel phase having a viscosity of at least 800 mPa.s and the gel former has a molecular weight of more than 20,000. The dispersions obtained have a long shelf life and the polymer can be readily precipitated.

Abstract: A dispersing stabilizer suitable for suspension polymerization of vinyl chloride or a monomer mixture mainly composed of vinyl chloride which can be used in a hot water charging polymerization process without any problems, and which can produce vinyl chloride homopolymer or copolymers having a good porosity, a large bulk density, a very low content of coarse particles and good physical properties, the dispersing stabilizer comprising a polyvinyl alcohol having a degree of hydrolysis of 75 to 85% by mole, an absorbance of not less than 0.1 measured at a wavelength of 280 m.mu. with respect to the 0.1% by weight aqueous solution, a content of carboxyl group of 0.01 to 0.15% by mole and a cloud point of not less than 50.degree. C. measured with respect to the 0.1% by weight aqueous solution.

Abstract: The invention relates to a homo- or copolymer of vinyl chloride. The polymer contains 0.01-50% of an oligomer of a C.sub.4 -C.sub.20 .alpha.-olefin or of an internal olefin or of their mixtures.

Abstract: A process for polymerizing vinyl chloride alone or a mixture of vinyl chloride and other vinyl monomer(s) with hydroxy containing monomer(s), and the copolymer obtained thereby. The hydroxy containing monomer(s) is obtained by the partial allylation of dihydroxy or polyhydroxy alcohols. The copolymers are prepared by suspension polymerization. The presence of the hydroxyl groups significantly modifies the characteristics of the polymers. Plasticizer-take-up is increased and dry-time is reduced significantly. Furthermore, the hydroxyl groups become the sites for postpolymerization reactions due to their polarity and reactivity.

Abstract: Mortar formulations comprising a hydraulic cement and a PVOH stabilized acrylic latex or a spray dried redispersible powder made from the PVOH stabilized acrylic latex are disclosed. These include formulations suitable for use as tile mortars, patching mortars, EIFS base coats and grouts. An acrylic latex that, when formulated with hydraulic cement, has performance advantages over other latex resins in mortar, patch and exterior insulation and finishing systems. The spray dried, redispersible acrylic emulsion polymer that, when formulated with hydraulic cement, has comparable or better performance than a liquid latex in mortars and patches.

Abstract: This invention is an emulsion composition comprised of acrylic ester monomers polymerized in the presence of fully hydrolyzed poly(vinyl alcohol) or a partially hydrolyzed poly(vinyl alcohol) provided the molecular weight of the low molecular weight poly(vinyl alcohol) is from 5,000 to 13,000 as the only stabilizer and a chain transfer agent. The improvement over the known prior art is the ability to incorporate fully hydrolyzed poly(vinyl alcohol) without the need for other surfactants or special processing.

Abstract: Aqueous emulsions of grafted polymer compositions are provided. The grafted component of these compositions has two or more polymeric substituents. The aqueous emulsions of grafted polymer compositions are particularly useful as cement modifiers.

Abstract: A vinyl chloride polymer is prepared through suspension polymerization of a vinyl chloride monomer in the presence of a polymerization initiator in a reactor. The reactor is charged with up to 4/5 of the overall monomer charge to initiate polymerization. Polymerization is carried out under a certain saturated vapor pressure of P1 kgf/cm.sup.2 at a preset polymerization temperature. When the internal pressure of the reactor declines to P2 kgf/cm.sup.2, the remainder of the overall monomer charge is continuously fed to the reactor so as to maintain the internal pressure within the range of (P1-.DELTA.P) wherein .DELTA.P=P1-P2 ranges from 0.1 to 2.0 kgf/cm.sup.2. A vinyl chloride polymer having a high degree of polymerization is efficiently produced while alleviating the load of heat removal.

Abstract: A vinyl compound is polymerized under suspension polymerization conditions by polymerizing the vinyl compound in a suspension polymerization medium containing, as the suspending agent, from 0.02 to 0.2 parts by weight of a polyvinyl alcohol polymer (A) having a degree of hydrolysis ranging from 60 to 95 mol % and a terminal mercapto group, based on 100 parts by weight of the vinyl compound. In another aspect of the invention, the suspending agent is a combination of said polyvinyl alcohol polymer (A) and a polyvinyl ester (B) having a degree of hydrolysis less than 60 mol %. The weight ratio of the two polymeric suspending agents (A)/(B) ranges from 40/60 to 95/5.

Abstract: Copolymers containing carboxyl groups in aqueous dispersion form or redispersible powder form and their water-soluble salts, based on ethylenically unsaturated and copolymerizable monomers, the macro-molecules of which contain at least 24% by weight of monomer units carrying carboxyl groups prepared, by emulsion copolymerization initiated by free radicals in the presence of polyvinyl alcohol (PVA) or polyvinylpyrrolidone (PVP) dissolved in the aqueous phase and isolation of the copolymers in aqueous dispersion form, and optionally subsequent removal of water by spray drying to obtain redispersible copolymer powders and processes for their preparation and their use as thickeners in aqueous formulations which copolymers, by conversion into their water-soluble salt forms, are useful as thickening agents having a surprisingly advantageous rheology-modifying action in aqueous systems.

Abstract: A process for the preparation of a synthetic resin dispersion stabilized by a protective colloid employing at least one initiator and based on a polymer of (a) a first monomer of at least one ester of acrylic acid or methacrylic acid and an alcohol containing 1 to 22 carbon atoms; and optionally, (b) a second monomer which can be copolymerized with the first monomers. The process comprises introducing at least 50% of the monomers based on the total weight of the monomers, at least 50% of the protective colloid based on the total weight of the protective colloid, and up to 50% of the initiator based on the total weight of the initiator into a reaction vessel to form an aqueous emulsion. Any remaining monomers and protective colloid and at least 50% of the initiator based on the total weight of the initiator are then added to the reaction vessel at a temperature of 30.degree. to 100.degree. C.

Abstract: This process uses, as dispersion stabilizers, (A) a partially saponified polyvinyl alcohol having an average polymerization degree of 300 to 2,000, a saponification degree of 70 to 85 mol %, and a mercapto group at least one terminal ends of its molecule chain, and (B) a hydroxypropylmethyl cellulose having a methoxy substitution of 26 to 30% by weight, a hydroxypropoxy substitution of 4 to 15% by weight, and a viscosity of 5 to 4,000 cP at 20.degree. C. in the state of a 2 weight % aqueous solution, in subjecting a vinyl monomer comprised mainly of vinyl chloride to suspension polymerization in an aqueous medium. A polymer which is high in porosity and will provide a molded item having few fish eyes can be produced in high productivity. Furthermore, since deposition of polymer scale on the inner wall of a polymerization vessel is little, removing the scale is easy and the polymerization vessel can be efficiently used.

Abstract: An aqueous resin dispersion for a heat-sensitive recording material is disclosed. The aqueous resin dispersion is obtained by the use of polyvinyl alcohol as an emulsifier and the use of two steps of polymerization. In the first step of polymerization, a polymeric monomer composition A is polymerized, composition A containing polymeric multi-functional monomers which constitute 15% by weight or more of the total weight of the polymeric monomers used for the first step. And, in the second step, a polymeric monomer composition B is polymerized, The invention also discloses a heat-sensitive recording material using such an aqueous resin dispersion as a color-developing layer or a protective coating.

Abstract: A method for making a polymer includes adding a first portion of a colloidal stabilizer to an aqueous medium, adding a monomer mixture, said monomer mixture including a monomer charge and a second portion of colloidal stabilizer and said monomer charge including from about 40 parts by weight to about 70 parts by weight of a vinyl ester monomer per 100 parts by weight monomer charge and from about 30 parts by weight to about 60 parts by weight of a (C.sub.1 -C.sub.12)alkyl (meth)acrylate monomer per 100 parts by weight monomer charge, to the aqueous medium and polymerizing the monomers to form an emulsion of the polymer in the aqueous medium.

Abstract: A process for the preparation of emulsion polymers comprising 70 to 95% by weight of a vinyl ester and 5 to 30% by weight ethylene, the polymerization being carried out in the presence of 2 to 8% by weight of a protective colloid consisting of a blend of 1 to 3 percent by weight of 80% hydrolyzed polyvinyl alcohol, 0 to 2 percent by weight of 88% hydrolyzed polyvinyl alcohol and 1 to 3 percent by weight of 96% hydrolyzed polyvinyl alcohol, the blend having an average level of hydrolysis of 85 to 88%.

Abstract: A vinyl acetate-ethylene copolymer emulsion having a solids content of at least 65 percent by weight is disclosed. Specifically, the copolymer emulsion comprises about 5 to 40 percent by weight ethylene, about 60 to 95 percent by weight vinyl acetate, about 0.8 to 2.0 percent by weight of a fully or partially hydrolyzed polyvinyl alcohol, and a mixture of nonionic ethoxylated alkyl phenol surfactants having a HLB of from about 16.0 to 16.5.

Abstract: Epoxy-containing compounds which are essentially free of organic halides are prepared by (I) reacting an allyl derivative of an active hydrogen-containing compound with (II) a peroxygen-containing compound. The epoxy-containing compounds are useful in coatings, castings, laminates etc.

Abstract: An emulsion adhesion composition comprising a polyvinyl alcohol stabilized polymer emulsion; the polymer comprising 40 to 94.5% by weight of a vinyl ester of an C.sub.1 -C.sub.13 alkanoic acid, 5 to 40% by weight ethylene and 0.5 to 10% by weight N-vinyl formamide or N-vinyl pyrrolidone, the adhesive being characterized by superior adhesion and heat resistance.

Abstract: A method for preparing an acrylic polymer powder which is redispersible in water by atomizing an aqueous polymer dispersion containing a dispersing aid, the improvement which comprises employing an acrylic polymer containing 1-15 wt % olefinically unsaturated carboxylic acid comonomer and an effective amount of a dispersing aid consisting essentially of polyvinyl alcohol.

Abstract: Polyvinyl chloride is prepared by suspension polymerization of a monomeric charge of vinyl chloride dispersed and suspended in an aqueous medium while agitating the suspension. An oil-soluble partially saponified polyvinyl alcohol is added to the monomeric charge as a dispersant at the start of polymerization. A water-soluble partially saponified polyvinyl alcohol and/or a hydroxypropylmethyl cellulose is continuously added as a suspending agent from the start of polymerization. The suspending agent is entirely added while the polymerization rate is in the range of 5-50%. The agitating power applied to the aqueous suspension is 50-110 kg.multidot.m/s.multidot.ton while the suspending agent is being added, and increased above 110 kg.multidot.m/s.multidot.ton after the completion of addition. The resulting polymer has a high bulk density and a sharp particle size distribution and is susceptible to extrusion.

Abstract: Vinyl chloride polymer is prepared by suspension polymerization of monomeric vinyl chloride or a mixture of vinyl chloride and another monomer in an aqueous medium while agitating the suspension. A first partially saponified polyvinyl alcohol having a degree of saponification of 60-80 mol % and an average degree of polymerization of 500-1,000 is added as a suspension stabilizer at the start of polymerization, and a second partially saponified polyvinyl alcohol having a degree of saponification of 75-85 mol % and an average degree of polymerization of 1,500-2,700 is added while the conversion is 30% to 60%. The agitating power is controlled to 80-120 kg.multidot.m/s.multidot.ton from the start of polymerization to a conversion of 20 to 50%, and to 130-200 kg.multidot.m/s.multidot.ton from then to the completion of polymerization.

Abstract: Reduction of the wall coating in reaction containers in the suspension polymerization of monomers containing acrylate and/or methacrylate groups and use of a buffer and of a dispersant for reducing the wall coating in reaction containers in the suspension polymerization of monomers containing acrylate and/or methacrylate groups.

Abstract: A method for producing a large size crosslinked polymer bead, which comprises dispersing a monomer phase composed essentially of a monovinyl monomer and a crosslinkable monomer in an aqueous phase containing a dispersion stabilizer and subjecting the dispersion to suspension polymerization in an oil-in-water system in the presence of a polymerization initiator, wherein: 1 at least one specific gravity-controlling agent having a specific gravity of more than 1.0 selected from the group consisting of water-insoluble inert organic solvents and water-insoluble linear polymers soluble in the monomer phase, is added to the monomer phase, and 2 if necessary, at least one specific gravity-controlling agent selected from the group consisting of water-soluble inorganic salts, is added to the aqueous phase, 3 to adjust the specific gravities (at 25.degree. C.) of the monomer phase and the aqueous phase in the ranges represented by the following formula (I):B-0.03<A<B+0.