Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F2/00—Processes of polymerisation
  • C08F2/12—Polymerisation in non-solvents
  • C08F2/16—Aqueous medium
  • C08F2/22—Emulsion polymerisation
  • C08F2/24—Emulsion polymerisation with the aid of emulsifying agents
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F2/00—Processes of polymerisation
  • C08F2/002—Scale prevention in a polymerisation reactor or its auxiliary parts
  • C08F2/004—Scale prevention in a polymerisation reactor or its auxiliary parts by a prior coating on the reactor walls

Definitions

• the coating can be applied to the inner surfaces of the reactor without opening the same thus providing a closed polymerization system.
• “heavy coating” is meant one that is substantially thicker, or heavier, than a thin, or monolayer, coating.
• a heavy film or coating of an unneutralized condensed polyhydric phenol or naphthol is applied to the interior surface of a polymerization reactor or vessel by contacting said surfaces with an alcohol solution of said unneutralized condensed polyhydric phenol of naphthol.
• all exposed surfaces in the interior of the reactor such as the baffles, agitator or mixing mechanism, the condenser when one is employed, and the like, are also treated in like manner. After the alcohol coating solution has been applied to the interior surfaces, the heavy film or coating thereon is dried.
• any suitable means may be employed for drying the coating, such as by flushing the reactor with hot air or steam to sweep the alcohol vapors out, by heating the reactor surfaces by circulating hot water through the jacket surrounding the reactor, and the like.
• the alcohol vapors can be sent to a recovery system but usually the same are vented to the atmosphere.
• the emulsion polymerization medium is charged into the reactor and the reaction started. The heavy coating or film is not substantially affected by the polymerization medium even though vigorously agitated during the polymerization reaction.
• the self-condensed and co-condensed polyhydric phenols useful in the present invention are made by heating any one or more of resorcinol, hydroquinone, catechol or phloroglucinol either with or without a suitable catalyst.
• the same is true for the self-condensed polyhydric naphthols, such as, for example, 2,7-dihydroxy naphthalene, 3 ,7-dihydroxy naphthalene, 2,6-dihydroxy naphthalene, and the like.
• the polyhydric phenol of naphthol is heated under an inert atmosphere, such as nitrogen, argon, and the like, at a temperature in the range of about 210°C.
• catalysts may be employed in the reaction, such as zinc chloride, aluminum chloride, sodium hydroxide, and the like. It has been found that the sodium hydroxide catalyst gives the best results.
• a catalyst concentration of from about 0.05 mole to about 0.50 mole per mole of the compound or compounds being condensed is satisfactory.
• the amount of catalyst employed is not critical. It is understood, of course, that the particular time and temperature selected is dependent upon the catalyst employed and the final desired molecular weight of the condensation product.
• the coating solutions of the present invention are made by conventional methods, using heat and agitation where necessary. Usually a temperature in the range of about 20°C. to about 30 °C. is satisfactory. Agitation during dissolution is desirable.
• the concentration of the condensation product in the coating solution will be in the range of about 1.0% to about 20.0% by weight, and preferably in the range of about 5.0% to about 10.0% by weight of the condensation product has an effect on the concentration of the condensation product in the coating solution of the total solids content of said solution. Since the molecular weight of the condensation product affects the total solids content in the coating solution, the concentration of the condensation product therein could, in certain instances, be greater than 20.0%.
• organic solvents that may be used in making the coating solutions of the present invention there may be named; saturated alcohols containing from 1 to 8 carbon atoms, such as methanol, ethanol, isopro panol, butanol, hexanol, 2-ethyl hexanol, and the like; ketones containing from 1 to 8 carbon atoms, such as methyl ethyl ketone, acetone, and the like; aldehydes containing from 1 to 8 carbon atoms, such as acetaldehyde, and the like; acetates, such as ethyl acetate, butyl acetate, and the like; and tetra-hydrofuran.
• saturated alcohols containing from 1 to 8 carbon atoms such as methanol, ethanol, isopro panol, butanol, hexanol, 2-ethyl hexanol, and the like
• ketones containing from 1 to 8 carbon atoms such
• a sufficient amount of heavy coating solution is painted or brushed on the reactor surfaces or sprayed on and dried there in order for an effective film or coating to form. Spraying of the coating solution onto the reactor surfaces is preferred since it is the most practical and economical method of application.
• the thickness of the coating on the reactor surfaces is set by the concentration of the condensation product in the coating solution, the quantity of coating solution used, and the degree of run-off before the coating dries in place. The excess coating solution that runs off can be recovered and reused or it can be disposed of by usual methods, depending upon the amount that runs off prior to complete drying.
• the degree of run-off is low since the drying cycle is relatively short, that is, in reactors having a capacity of 3,000 gallons or more, the drying cycle will be in the range of about 1 minute to about 10 minutes. Usually with most coating solutions, the drying time will be about 2 minutes or less.
• the thickness of the film or coating will be in the range of about 5 microns to about 50 microns, and preferably, in the range of about 5 microns to about 15 microns.
• the coating should not be too thick due to the increased intensity of the color thereof with increased thickness.
• a 5 micron thick film which is tough and water-insoluble, is amber colored. The danger of the film or coating flaking off during the polymerization reaction is practically zero so that the color problem is not all that great.
• the thickness of the coatings of the present invention are in quite a contrast with the invisible, absorbed monolayer films used heretofore in suspension polymerization.
• the average film thickness can be as low as 50 ⁇ which is 1/1,000th as thick as a 5 micron film.
• the coatings of the present invention work equally well on glass or metal surfaces, such as stainless steel, and the like. While no special cleaning of said surfaces is necessary prior to application of the coating solution, it has been found that the most satisfactory results are obtained when the surfaces are first cleaned.
• the surfaces can be cleaned with chemical agents, such as chromic acid, etc. or with an abrasive cleaner, such as Ajax®, and the like, and then rinsed with water and dried prior to application of the coating solution. High pressure water cleaning of the surfaces can also be used. Starting with clean surfaces enhances the adhesion of the coating thereto.
• multiple polymeriza tions may be run without opening the reactor between charges.
• these steps can be accomplished without reopening the reactor. This process can be repeated after each charge or periodically after a certain number of charges, depending upon ones production schedule and the down-time allotted to each reactor. It is understood, of course, that one can recoat the reactor as often as desired without opening the same, even after every charge is polymerized, thus preventing the escape of unreacted monomer(s) to the atmosphere of the plant.
• esters of acrylic acid for example methyl aerylate, ethyl aerylate, butyl aerylate, octyl acrylate, cyanoethyl aerylate, and the like
• esters of methacrylic acid such as methyl methacrylate, butyl methacrylate, and the like
• nitriles such as acrylonitrile and methacrylonitrile
• acrylamides such as methyl acrylamide, N-methylol acrylamide, N-butoxy methacrylamide, and the like
• vinyl ethers such as ethyl vinyl ether, chloroethyl vinyl ether, and the like
• vinyl naphthalene allyl and vinyl chloroacetate
• the aqueous reaction medium will contain one or more emulsifiers or an emulsifier system, such as a salt of a long chain fatty acid and a long straight chain saturated alcohol.
• an alkali metal or ammonium salt of a long chain saturated fatty acid is used as emulsifier or as part of the emulsifier system.
• the saturated fatty acids referred to may be either natural or synthetic and should contain from 8 to 20 carbon atoms. As examples of such acids there may be named lauric, myristic, palmitic, marganic, stearic, and the like, beef tallow, coconut oil, and the like.
• anionic emulsifiers such as the alkali metal or ammonium salts of the suifates of alcohols having from 8 to 18 carbon atoms.
• emulsifiers there may be named sodium lauryl sulfate, ethanolamine lauryl sulfate, ethylamine lauryl sulfate, and the like; alkali metal and ammonium salts of sulfonated petroleum and paraffin oils; sodium salts of hydrocarbon sulfonic acids, such as dodecane-1- sulfonic acid and octadiene-1-sulfonic acid; sodium salts of alpha-olefin sulfonates; aralkyl sulfonates, such as sodium isopropyl benzene sulfonate, sodium dodecyl ben zene sulfonate, sodium isobutyl nephthalene sulfonate
• Nonionic emulsifiers such as octyl- or nonylphenyl polyethoxyethanol, may also be used. Vinyl polymer latices having excellent stability are obtained when employing the alkali metal and ammonium salts of aromatic sulfonic acid, aralkyl sulfonates and long chain sulfonates.
• the emulsifier is employed in an amount in the range of about 0.1% to about 5.0% by weight, based on the weight of monomer or monomers being polymerized, and preferably, an amount of emulsifier in the range of about 0.5% to about 1.5% is used. When employing more than one emulsifier in the system, the combined weight thereof will be in the same ranges.
• alcohols there may be named octanol, nonanol, decanol, undecanol, dodecanol, tridecanol, tetradecanol, pentadecanol, heptadecanol, octadecanol, nonadecanol, eicosanol, heneicosanol, docosanol, tricosanol, tetracosanol, etc.
• a mixture of alcohols there may be mentioned the use of a 12 carbon alcohol olus an 18 carbon alcohol.
• ethoxylated alcohols can be used, such as a mixture of ethoxylated linear primary alcohols containing from 12 to 15 carbon atoms, etc.
• the ratio of alcohol to emulsifier can range from 0.15 to 1.0 or greater depending upon the emulsifier being used.
• the emulsifier is an ammonium salt of a fatty acid
• the ratio of alcohol to fatty acid salt can be 1.0 but preferably the ratio is greater than 1.0.
• the emulsion polymerization process of vinyl monomers the same is conducted at a pH in the range of about 2.0 to about 10.0. If the pH is too high it takes too much alkali and if the pH is too low the coagulum increases.
• the various peroxygen compounds such as lauryl peroxide, isopropyl peroxydicarbonate, bis (4-tert-butyl cyclohexyl) peroxydicarbonata, di (2-ethyl hexyl) peroxydicarbonate, diisononanoyl peroxide, benzoyl peroxide, t-butyl hydroperoxide, t-butyl peroxypivalate, cumene hydroperoxide, cyclohexyl hydroperoxide, test-butyl peroxyneodecanoate, and the like; azo compounds, such as axodiiscbutyronitrile, dimethylazodiisobutyrate, and the like.
• initiators or catalysts are the water-soluble peroxygen compounds, such as hydrogen peroxide, persul fates, such as potassium persulfate, ammonium persulfate, and the like.
• mixtures of catalysts or initiators may be employed, either water-insoluble or water-soluble or both.
• a 50-50 mixture of di(2-ethyl hexyl) peroxydicarbonate and diisononanoyl peroxide can be used.
• the amount thereof will be in the range of about 0.01% to about 0.50% by weight, based on the weight of 100 parts of monomer or monomers being polymerized, and preferably in the range of about 0.015% to about 0.15% by weight.
• the initiators may be charged to the reactor after the reaction ingredients have been mixed or charged incrementally during the course of the reaction, usually, in most emulsion polymerization processes the initiators are charged completely at the outset of the polymerization by addition to the monomer premix with the other ingredients of the reaction mixture.
• the reaction ingredients are mixed to form the monomer premix prior to homogenization and introduction into the reactor.
• the temperature is then raised to that at which the reaction is to take place.
• the choice of temperature at which to conduct the emulsion polymerization reaction is important since the inherent viscosity (IV) of the plastisols made with the vinyl dispersion resins thus produced is a direct function of the temperature of reaction. That is, the higher the reaction temnerature the lower the IV. Accord ingly, the end use for the vinyl dispersion resin being produced will normally dictate the emulsion polymerization reaction temperature.
• polymerization temperatures in the range of about 30°C. to about 70°C. are satisfactory.
• a temperature in the range of about 40°C. to about 55°C. is employed.
• the vinyl polymer latices are sold as such, but in most instances the vinyl polymer or resin is sold in dry powder form.
• the vinyl dispersion resin is isolated in powder form from the latex by means of spray drying. That is, a fine spray of the polymer latex is injected into a heated air chamber thereby removing the water, and any unreacted monomer, and recovering the dried resin in powder form.
• Example II In this example, a series cf 4 runs were made using a coated reactor. The polymerization procedure of Example I was employed in each ofi the runs. Before coating, the reactor surfaces were super cleaned and then coated with a 5% solution of self-condensed resor cinol in ethanol. The coating solution was applied by means of spraying and then dried. It took about 4 to 5 pounds of coating solution. Thereafter, the first run was made. After each run the reactor was rinsed with water to remove any buildup prior to- starting the next run. No further coating solution was applied between runs. Results were tabulated after each run and these results are shown in the following table:

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• Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Polymerisation Methods In General (AREA)
• Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)

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• 1981
  • 1981-07-24 BR BR8108752A patent/BR8108752A/pt unknown
  • 1981-07-24 JP JP56502734A patent/JPS57501286A/ja active Pending
  • 1981-07-24 WO PCT/US1981/000994 patent/WO1982000645A1/en not_active Application Discontinuation
  • 1981-07-24 EP EP19810902171 patent/EP0058169A4/en not_active Withdrawn
  • 1981-08-07 IT IT23441/81A patent/IT1138142B/it active
  • 1981-08-18 BE BE0/205706A patent/BE890007A/fr unknown
  • 1981-08-24 PT PT73564A patent/PT73564B/pt unknown
  • 1981-08-24 ES ES504930A patent/ES504930A0/es active Granted
  • 1981-08-25 GR GR65866A patent/GR75745B/el unknown
• 1982
  • 1982-04-22 NO NO821313A patent/NO821313L/no unknown
  • 1982-04-23 DK DK183382A patent/DK183382A/da not_active Application Discontinuation

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