WO1999044737A1 - Procede de production en continu de dispersions de polymeres par polymerisation en emulsion aqueuse - Google Patents

Procede de production en continu de dispersions de polymeres par polymerisation en emulsion aqueuse Download PDF

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Publication number
WO1999044737A1
WO1999044737A1 PCT/EP1999/001375 EP9901375W WO9944737A1 WO 1999044737 A1 WO1999044737 A1 WO 1999044737A1 EP 9901375 W EP9901375 W EP 9901375W WO 9944737 A1 WO9944737 A1 WO 9944737A1
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monomers
curvature
reactor
emulsion
flow reactor
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PCT/EP1999/001375
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German (de)
English (en)
Inventor
Claudia Heibel
Jens KREMESKÖTTER
Walter Kastenhuber
Steffen Funkhauser
Wolfgang HÜBINGER
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Basf Aktiengesellschaft
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Publication of WO1999044737A1 publication Critical patent/WO1999044737A1/fr

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J19/24—Stationary reactors without moving elements inside
    • B01J19/2405—Stationary reactors without moving elements inside provoking a turbulent flow of the reactants, such as in cyclones, or having a high Reynolds-number
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J19/24—Stationary reactors without moving elements inside
    • B01J19/2415—Tubular reactors
    • B01J19/243—Tubular reactors spirally, concentrically or zigzag wound
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J2219/00049—Controlling or regulating processes
    • B01J2219/00051—Controlling the temperature
    • B01J2219/00074—Controlling the temperature by indirect heating or cooling employing heat exchange fluids
    • B01J2219/00087—Controlling the temperature by indirect heating or cooling employing heat exchange fluids with heat exchange elements outside the reactor
    • B01J2219/00094—Jackets

Definitions

  • the present invention relates to a process for the continuous production of polymer dispersions, in which the dispersed particles have an average particle size of ⁇ 200 n, by aqueous radical emulsion polymerization of at least one ethylenically unsaturated monomer.
  • reactors which consist of two concentric cylinders, the inner and / or outer cylinder being set in rotation.
  • Such reactors and their use for emulsion polymerization are described in Polymer International 30 (1993), 203-206; Chemical Engineering Science, Vol. 50, 1409-1416 (1995); and in EP-A-498 583.
  • reactors of this type similar disadvantages occur as in the reactors described in DE-A-1 071 341.
  • tubular reactors are often used without additional internals, such as a static mixer or a stirrer.
  • a static mixer or a stirrer.
  • Patent publications describing tubular reactors for emulsion polymerization are DE-A-26 17 570, DD-A-238 163, DD-A-234 163, DD-A-233 573, DD-A-233 572, DE-A -33 02 251, CZ-A-151 220 and EP-A-633 061.
  • the present invention is therefore based on the object of providing a process for the continuous production of polymer dispersions by aqueous emulsion polymerization, in which the formation of coagulum is reduced.
  • This object is achieved by a process for the continuous production of a polymer dispersion in which the dispersed particles have an average particle size of ⁇ 200 nm (determined using an analytical ultracentrifuge), by aqueous radical emulsion polymerization of at least one ethylenically unsaturated monomer M, Produces emulsion of the monomer or monomers in an aqueous phase and polymerizes the emulsion in a curved tubular flow reactor having a substantially circular or ellipsoidal cross section, the flow reactor having a plurality of curvatures with an alternating direction of curvature and a change in the direction of curvature occurring at the latest when the ab
  • the distance of the center of gravity of the pipe cross-sectional area is 200 times the pipe diameter, whereby a curvature can comprise up to three revolutions around the curvature axis.
  • the average particle size of the dispersed polymer particles is preferably ⁇ 150 nm, in particular ⁇ 100 nm.
  • Suitable monomers M generally comprise at least one monomer Ml which is selected from vinylaromatic monomers such as styrene, ⁇ -methylstyrene, ortho-chlorostyrene or vinyltoluenes, the vinyl esters of aliphatic monocarboxylic acids with 1 to 12 carbon atoms such as vinyl acetate, vinyl propionate and vinyl butyrate , Vinyl valerate, vinyl hexanoate, vinyl 2-ethyl hexanoate, vinyl decanoate, vinyl laurate and Vinylversatat® (vinyl esters of branched, aliphatic carboxylic acids with 6 to 11 C atoms, which are commercially available as Versatic® X acids from SHELL AG).
  • vinylaromatic monomers such as styrene, ⁇ -methylstyrene, ortho-chlorostyrene or vinyltoluenes
  • esters of ⁇ , ⁇ -ethylenically unsaturated C 8 -C 8 -mono- or C 4 -C 8 -dicarboxylic acids with C 1 -C 12 - and in particular Ci-Cs-alkanols or Cs-Cs-cycloalkanoias come in as Monom ⁇ re Ml Question.
  • Suitable CC 2 alkanols are, for example, methanol, ethanol, n-propanol, i-propanol, 1-butanol, 2-butanol, isobutanol, tert-butanol, n-hexanol and 2-ethylhexanol.
  • Suitable cycloalkanols are, for example, cyclopentanol or cyclohexanol.
  • Esters of acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, citraconic acid or fumaric acid are particularly suitable.
  • acrylic acid methyl ester (meth) acrylic acid ethyl ester, (meth) acrylic acid n-butyl ester, (meth) acrylic acid isobutyl ester, (meth) acrylic acid tert-butyl ester, (meth) acrylic acid 1-hexyl ester, (meth) acrylic acid-2-ethylhexyl ester, maleic acid dimethyl ester or maleic acid di-n-butyl ester.
  • the monomers Ml also include monomers such as butadiene, C 2 -C 6 -01efins such as ethylene, 1-propene, 1-butene, isobutene and 1-hexene and vinyl and vinylidene chloride.
  • esters of ⁇ , ⁇ -ethylenically unsaturated mono- or dicarboxylic acids make up 50 to 100% by weight of the monomers and the vinylaromatic compounds 0 to 50% by weight, based on the total amount of the monomers to be polymerized.
  • the monomers M1 comprise:
  • At least one monomer Mlb selected from the C 4 -C 4 -alkyl esters of methacrylic acid, for. B. methyl methacrylate, ethyl methacrylate, n-butyl methacrylate 4 and tert-butyl methacrylate, and vinyl aromatic monomers, e.g. B. styrene and ⁇ -methylstyrene,
  • the weight of the monomers Mla and Mlb being added to 100% by weight.
  • the polymers often also contain copolymerized monomers which have an acidic functional group. This applies in particular to those polymers which contain vinyl-aromatic compounds and / or one or more of the abovementioned alkyl esters of ethylenically unsaturated carboxylic acids in copolymerized form.
  • monomers M2 with acidic functional groups are ethylenically unsaturated mono- and dicarboxylic acids, e.g.
  • Example acrylic acid, methacrylic acid, acrylamidoglycolic acid, crotonic acid, itaconic acid, fumaric acid, maleic acid, and also the half esters of ethylenically unsaturated dicarboxylic acids with C 1 -C 2 -alkanols, for.
  • B monomethyl maleate and mono-n-butyl maleate.
  • Monomers M2 also include monomers with sulfonic acid groups and / or phosphonic acid groups or their salts, in particular their alkali metal salts.
  • Examples include vinyl and allylsulfonic acid, (meth) acrylamidoethanesulfonic acid, acrylamidopropanesulfonic acid, (meth) acrylamido-2-methylpropanesulfonic acid, vinyl- and allylphosphonic acid, (meth) acrylicoxyethyophosphonic acid, (meth) acrylamidoethanephosphonic acid and (meth) acrylamido 2-methylpropanephosphonic acid and the salts thereof, such as sodium vinyl sulfonate.
  • the monomers M2 are used in amounts of 0.1 to 10% by weight and in particular in amounts of 0.2 to 5% by weight, based on the total weight of the monomers M.
  • the dispersed polymers can also contain copolymerized monomers M3 which have an increased water solubility, i. H. greater than 60 g / 1 at 25 ° C, and which, in contrast to the monomers M2, do not contain a neutralizable, acidic group.
  • copolymerized monomers M3 which have an increased water solubility, i. H. greater than 60 g / 1 at 25 ° C, and which, in contrast to the monomers M2, do not contain a neutralizable, acidic group.
  • These include the amides of the aforementioned ethylenically unsaturated carboxylic acids, eg. B. acrylamide and met acrylamide, N-vinyl acetate, e.g. B. N-vinyl pyrrolidone and N-vinyl caprolactam, also acrylonitrile and methacrylonitrile.
  • the monomers M3 are used in amounts of 0.1 to 10% by weight, based on the total weight of the monomers M to be polymerized, the monomers acrylonitrile and methacrylonitrile also in amounts of up to 50% by weight. , and preferably up to 30 wt .-% can be present.
  • the dispersed polymers can also contain, in copolymerized form, those monomers M4 which increase the crosslinking density of the polymers. These are in a minor amount, usually up to 10 wt .-%, preferably up to 5 wt .-% and in particular 5 to 1% by weight, based on the total amount of the monomers to be polymerized, also copolymerized.
  • the monomers M4 comprise compounds which, in addition to a polymerizable double bond, contain at least one epoxy, hydroxyl, N-alkylol or a carbonyl group.
  • N-hydroxyalkyl and N-alkylolamides of ⁇ , ⁇ -monoethylenically unsaturated carboxylic acids having 3 to 10 carbon atoms such as 2-hydroxyethyl (meth) acrylamide and N-methylol (meth) acrylamide
  • the hydroxyalkyl esters of said ethylenic unsaturated carboxylic acids for example hydroxyethyl, hydroxypropyl and hydroxybutyl (meth) acrylate
  • the ethylenically unsaturated glycidyl ethers and esters for example vinyl, allyl and metal glycidyl ethers, glycidyl acrylate and methacrylate
  • diacetone nylamides of the above-mentioned ethylenically unsaturated carboxylic acids for example diacetonyl (meth) acrylamide
  • the monomers M4 comprise compounds which have two non-conjugated, ethylenically unsaturated bonds, for example the diesters of dihydric alcohols with ⁇ , ⁇ -monoethylenically unsaturated C 3 -C 1 -monocarboxylic acids.
  • alkylene glycol diacrylates and dimethacrylates such as ethylene glycol diacrylate, 1, 3-butylene glycol diacrylate, 1, 4-butylene glycol diacrylate, propylene glycol diacrylate, divinylbenzene, Vinylmetha- methacrylate, leat vinyl acrylate, allyl methacrylate, allyl acrylate, diallyl maleate, diallyl fumarate, Methylenebisacrylamide, cyclopentadienyl acrylate, tricyclodecenyl (meth) acrylate, N, N '-divinylimidazolin-2-one or triallyl cyanurate.
  • alkylene glycol diacrylates and dimethacrylates such as ethylene glycol diacrylate, 1, 3-butylene glycol diacrylate, 1, 4-butylene glycol diacrylate, propylene glycol diacrylate, divinylbenzene, Vinylmetha- methacrylate, leat vinyl acrylate, allyl methacryl
  • the dispersed polymers can also contain modifying monomers in copolymerized form. These include hydrophobically modifying monomers, monomers which increase the wet adhesion of coatings based on aqueous polymer dispersions, and those monomers which improve the pigment-binding power of aqueous polymer dispersions, provided the polymer dispersions are used as binders for emulsion paints.
  • Monomers which improve wet adhesion include, in particular, polymerizable derivatives of imidazolidin-2-one (see, for example, EP-A 184 091, US Pat. No. 4,219,454).
  • Monomers which improve the pigment binding power of aqueous polymer dispersions are known to be monomers containing siloxane groups (see, for example, EP-A 327 006, EP-A 327 376).
  • the polymers dispersed in the aqueous polymer dispersions to be stabilized according to the invention can also comprise monobolymer hydrophobically and / or hydrophilically modifying 6 included.
  • Hydrophobic-modifying monomers are, in particular, those monomers with a low water solubility (ie less than 0.01 g / 1 at 25 ° C.). These include, for example, the -C 22 alkyl esters of ethylenically unsaturated carboxylic acids, for. B. stearyl acrylate and stearyl methacrylate, the vinyl and allyl esters of saturated fatty acids, e.g. B. vinyl stearate, also olefins with more than 6 carbon atoms, and C -C alkyl-substituted, vinyl aromatic compounds, eg. B. tert-butyl styrene.
  • the monomers to be polymerized are particularly preferably selected so that a polymer is obtained which has a glass transition temperature of ⁇ 35 ° C. (determined by means of differential thermal analysis, with Point, ASPM), in particular ⁇ 30 ° C. and preferably ⁇ 20 ° C.
  • the glass transition temperature is particularly preferably in the range from -50 ° C. to + 30 ° C., in particular -45 to + 20 ° C.
  • the monomer emulsion is prepared by emulsifying the monomers in the aqueous phase.
  • the monomers are emulsified in a customary manner, for example by ultrasound homogenization using an ultrasound sonotrode and / or by using a static and / or dynamic mixer. This is preferably done by installing the mixer in-line.
  • Suitable mixers are known to the person skilled in the art, for example static mixers, e.g. of the Sulzer SMX type or high-speed dynamic mixers, high-pressure homogenizers, gas injectors, high-pressure perforated membranes, etc. that work on the rotor-stator principle.
  • the monomers can be emulsified individually or as a mixture in the aqueous phase. It is preferred to first pre-emulsify the monomers, for example using a static mixer, and then to homogenize them, for example using a dynamic mixer.
  • the individual components of the monomer emulsion can be fed in completely continuously, partially continuously or in a mixed form of fully and partially continuously.
  • all individual components ie water, emulsifier, various monomers and auxiliaries, are metered separately, for example via a pipeline or from a storage tank, continuously into the device used for emulsification in the desired ratio via a mixture control.
  • the emulsion emerging from the device then has the correct composition and can be fed continuously into the reactor. 7
  • At least two batch tanks are used.
  • the emulsion is produced in one of the batch containers and can then be fed continuously into the reactor.
  • a further batch of the emulsion is produced in the second batch container.
  • the switch is made to the second batch container and the reactor is continuously charged with the emulsion in this way.
  • a mixed mode approach the two previous approaches are combined.
  • Some of the components are provided in one or more batch containers and continuously dosed therefrom into an emulsifying device. If necessary, an intermediate vessel is also sufficient for individual components, the period of time until the intermediate vessel is empty enough to provide a new batch in the upstream batch container. Further components are metered directly into this emulsifying device, for example from a pipeline or a storage tank. The emulsion emerging from the emulsifying device then has the correct composition and is fed into the reactor.
  • auxiliary devices or apparatuses for controlling the temperature and / or the pressure or other properties of the respective metering streams can additionally be provided.
  • the polymerization initiator can be mixed in during the preparation of the emulsion or afterwards. For security reasons, it will be added as late as possible. It has proven to be particularly preferred to first prepare the emulsion and then to mix in the polymerization initiator.
  • the initiator is preferably mixed in under the temperature conditions given below for the emulsification.
  • the polymerization temperature differs.
  • both the pre-emulsification and the homogenization and mixing in of the polymerization initiator are preferably carried out at this temperature. It is preferred to work, in particular at a polymerization temperature above 60 ° C., at a temperature which is lower than the polymerization temperature.
  • the emulsion polymerization can also be carried out in the presence of seed latex to set a defined polymer particle size.
  • 0.01 to 3% by weight and in particular 0.05 to 1.5% by weight of a seed latex solids content of the seed latex, based on the total amount of monomer is preferably used.
  • the latex generally has a weight-average particle size of 10 to 100 nm and in particular 20 to 50 nm.
  • the seed latex is preferably mixed in during the preparation of the monomer emulsion.
  • the aqueous phase of the emulsion can contain up to 30% by weight of a water-miscible organic solvent, such as methanol, ethanol, n-propanol, isopropanoi, n-butanol, isobutanol, t-butanol, acetone, methyl ethyl ketone and the like . contain.
  • a water-miscible organic solvent such as methanol, ethanol, n-propanol, isopropanoi, n-butanol, isobutanol, t-butanol, acetone, methyl ethyl ketone and the like .
  • the polymer dispersions are prepared by free-radical aqueous emulsion polymerization of the monomers mentioned in the presence of at least one free-radical polymerization initiator and, if appropriate, at least one surface-active substance.
  • Free radical polymerization initiators are all those which are capable of initiating a free radical aqueous emulsion polymerization. It can be both peroxides (preferred), e.g. B. alkali metal peroxodisulfates or alkali metal peroxides, as well as azo compounds. So-called redox initiators, which are composed of at least one organic reducing agent and at least one peroxide and / or hydroperoxide, z. B. tert-butyl hydroperoxide with sulfur compounds, e.g. B.
  • ascorbic acid / iron (II) sulfate / hydrogen peroxide 9 where, instead of ascorbic acid, the sodium salt of hydroxymethanesulfinic acid, acetone bisulfite, sodium sulfite, sodium bisulfite or sodium bisulfite and instead of hydrogen peroxide, organic peroxides such as tert-butyl hydroperoxide or alkali peroxodisulfates and / or ammonium peroxodisulfate are used.
  • the amount of free-radical initiator systems used is preferably 0.1 to 2% by weight, based on the total amount of the monomers to be polymerized.
  • Suitable surface-active substances for carrying out the emulsion polymerization are the protective colloids and emulsifiers which are usually used for this purpose.
  • the surface-active substances are usually used in amounts of up to 5% by weight, preferably 0.1 to 5% by weight and in particular 0.2 to 3% by weight, based on the monomers to be polymerized. However, larger quantities can also be used.
  • Suitable protective colloids are, for example, polyvinyl alcohols, starch and cellulose derivatives or copolymers containing vinyl pyrrolidone.
  • a detailed description of further suitable protective colloids can be found in Houben-Weyl, Methods of Organic Chemistry, Volume XIV / 1, Macromolecular Substances, Georg-Thieme-Verlag, Stuttgart 1961, pp. 411-420.
  • Mixtures of emulsifiers and / or protective colloids can also be used.
  • emulsifiers are used as surface-active substances, the relative molecular weights of which, in contrast to the protective colloids, are usually below 2000. They are preferably anionic or nonionic in nature.
  • the anionic emulsifiers include alkali and ammonium salts of alkyl sulfates (alkyl radical: C 8 -C 2 ), of sulfuric acid semiesters of ethoxylated alkanols (EO degree: 2 to 50, alkyl radical: C x to C 8 ) and ethoxylated alkyl phenols (EO degree: 3 to 50, alkyl radical: C 4 -C 9 ), of alkylsulfonic acids (alkyl radical: C ⁇ 2 -C 18 ) and of alkylsulfonic acids (alkyl radical: Cg to Cig).
  • alkyl sulfates alkyl radical: C 8 -C 2
  • sulfuric acid semiesters of ethoxylated alkanols EO degree: 2 to 50, alkyl radical: C x to C 8
  • ethoxylated alkyl phenols EO degree: 3 to 50, alkyl radical: C 4 -C
  • Suitable emulsifiers can be found in Houben-Weyl, Methods of Organic Chemistry, Volume XIV / 1-Macromolecular Substances, Georg-Thieme-Verlag, Stuttgart, 1961, pp. 192-208).
  • Suitable anionic emulsifiers are also the abovementioned salts S, in particular the salts of sulfonated succinic acid di-C 8 -C 8 -alkyl esters, and among these particularly preferably the sodium salts.
  • Preferred anionic emulsifiers are also mono- and di-C 2 -C 2 -alkyl derivatives of the doubly sulfonated diphenyl ether or its salts.
  • the mono- and di-C 6 -C 8 alkyl derivatives are particularly preferred.
  • Technical mixtures are frequently used which contain 50 to 90% by weight of the monoalkylated product. 10 sen, for example Dowfax® 2A1 (trademark of Dow Chemical Company).
  • the connections are e.g. B. from US-A-4, 269, 749 known and commercially available.
  • nonionic emulsifiers can also be used.
  • Suitable nonionic emulsifiers are araliphatic or aliphatic nonionic emulsifiers, for example ethoxylated mono-, di- and trialkylphenols (EO grade: 3 to 50, alkyl radical: C 4 -C 9 ), ethoxylates of long-chain alcohols (EO grade: 3 up to 50, alkyl radical: C 8 -C 36 ), and also polyethylene oxide / polypropylene oxide block copolymers.
  • ethoxylates of long-chain alkanols alkyl radical: C ⁇ o-C 2 , average degree of ethoxylation: 3 to 50
  • alkyl radical C ⁇ o-C 2 , average degree of ethoxylation: 3 to 50
  • ethoxylates of long-chain alkanols alkyl radical: C ⁇ o-C 2 , average degree of ethoxylation: 3 to 50
  • ethoxylates of long-chain alkanols alkyl radical: C ⁇ o-C 2 , average degree of ethoxylation: 3 to 50
  • the molecular weight of the polymers can be increased by adding small amounts, usually up to 2% by weight, based on the monomers to be polymerized, of one or more substances which regulate the molecular weight, for.
  • the monomer emulsion thus produced is then optionally brought to the polymerization temperature and fed continuously to the flow reactor and polymerized.
  • the flow reactor is described in PCT / EP97 / 04654, the content of which is hereby incorporated in its entirety.
  • Curves with an alternating direction of curvature are to be understood here as a sequence of curved pipe segments, the next pipe segment in each case (section of the pipe between two successive reversals of curvature, for example the sections between two axis intersections in FIG. 1) in a different, preferably the opposite direction of previous leads, ie there is a change, preferably a reversal of the direction of curvature with each curved pipe segment.
  • This design of the reactor achieves a flow that is as uniform as possible and thus narrows the residence time distribution of the volume units.
  • the design of the reactor allows the production of windings with a spatially particularly favorable, ie compact, arrangement, so that they are particularly suitable for industrial practice (more detailed information on the resulting structures follows below).
  • a high Bodenstein number can be achieved with the reactor, which is generally> 10 and preferably ⁇ 100 and can be up to 1000 and more. It is a measure of the width of the 11 time distribution, the higher it is, the narrower and more symmetrical the dwell time distribution.
  • the direction of curvature is preferably reversed at the latest when the distance of the center of gravity of the cross-sectional area of the pipe that has passed from the beginning of a curvature is 150 times, in particular 100 times, preferably 80 times, particularly preferably 50 times, 30 times or 25 times. times the pipe diameter.
  • This distance is generally at least 5 times the 10 pipe diameter and in particular it is in the range of 10 to 150 times, in particular 10 to 100 times, preferably 10 to 80 times and particularly preferably 10 to 50 times, 10 to 40 times or 10 to 30 times the pipe diameter.
  • a curvature can include not only a partial revolution, but also one and up to two or three revolutions around the axis of curvature (axis through the intersection of R x and R 2 , see FIG. 1). The angle that the normal vector of the main flow direction of a curvature traverses until the direction of curvature changes
  • Sinusoidal curvatures are in the present case
  • the radius of curvature of the curved pipe segments is preferably 0.5 to 100 times, preferably 1 to 40 80, 2 to 50 or 2 to 20 times the diameter of the pipe cross-sectional area.
  • the dimensions of the reactor are generally such that the ratio of length to diameter is in the range from 100: 1 to 45 1,000,000: 1, preferably 1,000: 1 to 100,000: 1 or 50,000: 1. 12
  • one or more of the curved pipe segments can be connected by straight pipe segments.
  • the ratio of straight to curved pipe section is then ⁇ 5, preferably ⁇ 2, in particular ⁇ 1 and particularly preferably ⁇ 0.5 or ⁇ 0.25.
  • the device can also be constructed from a plurality of reactor units, the reactor in each unit having different geometry and / or dimensions and / or radii of curvature.
  • the tube diameter can be increased in one unit in order to achieve a lower flow velocity or the radius of curvature can be varied in order to set special product properties.
  • the cross section of the reactor is preferably circular or ellipsoid. This also includes modified circular or elliptical cross sections, e.g. Cross sections resulting from rounding the corners of a square or a rectangle. In the case of swirl tubes (see below), the basic shape of the reactor tube is essentially circular or ellipsoid.
  • the ratio of the large semiaxis to the small semiaxis is generally in the range from 5: 1 to 1: 1, in particular in the range from 2: 1 to 1: 1.
  • the device is designed as an ascending and single-layer winding around at least two axes, as seen from the incoming flow.
  • the axes can form an angle to one another, but they are preferably essentially parallel. In the case of a non-self-supporting winding, these axes can preferably be realized by tubes or rods, which can be round or angular.
  • the term "winding around at least two axes" is used here only for illustration. It is not necessary that the axes are also implemented in the application, e.g. in the form of tubes or rods. With a winding around 2 parallel axes, e.g. the arrangement shown in Figures 2, 3 and 6.
  • a winding around a plurality of substantially parallel axes running through the corners of a polygon, in particular an equilateral polygon, and perpendicular to its surface.
  • the polygon can have an even and preferably an odd number of corners, namely at least 3 or 5.
  • a heptagon has proven to be particularly useful. 13 proved moderately (see Figures 7 and 8).
  • a polygonal winding can be understood by curvatures along angled axes joined to form a polygon (perpendicular to the preferably parallel axes mentioned).
  • the outside distance of the axes around which the winding is guided can be varied within a wide range. In general, it is 1 to 10 times, preferably 1 to 5 times and in particular 1 to 3 times the diameter of the reactor tube, the single to double distance being particularly preferred.
  • the winding is also determined by the pitch. It is generally 1 to 10 times, in particular 1 to 3 times the reactor diameter (in the case of a circular cross section) or in the case of an ellipsoidal reactor cross section of the axis which points in the direction of the path.
  • windings mentioned are a particularly favorable arrangement in terms of space and allow a compact design of the device according to the invention. They are easy to transport, which is particularly advantageous for maintenance work.
  • the number of windings arranged one above the other is arbitrary and depends on the respective requirements.
  • the curved reactor can, depending on the requirements of the reaction to be carried out, be made of metal, a metal alloy, glass or a plastic. There are no restrictions here, the tube only has to be resistant to the reactants and stable under the reaction conditions. If the reactor consists of metal, it can for example be made of copper or copper alloys, steel or stainless steel of any kind.
  • the reactor is made of a plastic
  • fluorine-containing plastics e.g. Tetrafluoroethylene
  • polyethylene, polypropylene or polyvinyl chloride are preferred.
  • the reactor can be made from profile tubes, in particular swirl tubes or corrugated tubes, or can have an inner coating. Depending on the requirements of the reaction to be carried out, this is chosen to be acid-proof, alkali-proof or solvent-proof, etc.
  • interior coatings are, in particular, fluorine-containing plastics, such as tetrafluoroethylene, polyethylene or polypropylene.
  • the inside of the tube can be rendered inert by chemical treatment, for example passivated by treatment with nitric acid, electropolished or mechanically polished. 14
  • the reactor according to the invention can have additional devices or can be combined with other apparatus.
  • means for feeding chemicals for example catalysts, reagents, solvents etc. and / or for cleaning, e.g. be provided by using pig systems.
  • the reactor can use pulsating agents, e.g. Pumps, to accomplish a pulsed reaction.
  • devices can be provided at the beginning or at any point along the curved tube with which, e.g. for the purpose of separation, gas bubbles of an inert gas, such as nitrogen and / or pigs, can be fed.
  • customary mixing elements can be provided on sub-segments of the curved reactor, which generally do not exceed 10% of the reactor distance, for example packing elements, static or dynamic mixers.
  • measuring points and devices for sampling are also provided along the curved reactor.
  • the reactor generally also comprises means for heating or cooling the medium flowing through.
  • a heatable or coolable container which may be divided into zones, can be used, which completely or partially encloses the tubular reactor in order to control the temperature in the desired manner. It is also possible to let the heating or cooling medium flow through the pipes around which the pipe reactor is wound.
  • the reactor can also be equipped with jacket heating or cooling.
  • the reactor can be combined in any way with other apparatus which can be connected upstream and / or in parallel and / or downstream.
  • the spatial orientation of the reactor is not restricted. However, an alignment with an essentially horizontal and / or continuously increasing pipe run is preferred.
  • the direction of flow is preferably from bottom to top.
  • reaction temperature is generally in the range from 40 to 150 ° C., in particular 60 to 120 ° C.
  • the reactor is further illustrated by the following figures. Show it:
  • FIG. 1 shows a schematic illustration of a sinusoidal curvature
  • Figure 2 is a side view of a reactor in the form of a winding around two rods
  • FIG. 3 shows a plan view of the reactor according to FIG. 2
  • Figure 4 shows a reactor in the form of a winding around six rods arranged in one plane
  • FIG. 5 is a top view of the reactor according to FIG. 4
  • FIG. 6 shows the side view of a reactor in the form of a winding around two rods modified compared to FIG.
  • FIG. 7 shows a schematic partial view of a reactor in the form of a winding around 7 rods arranged at the corners of an equilateral polygon
  • FIG. 8 shows a schematic plan view of a winding loop according to FIG. 7.
  • Figure 2 shows a reactor in the simplest embodiment as a winding.
  • the reactor comprises two parallel rods 1.
  • a tube is wound around these rods in such a way that a curved reactor 2 with an alternating direction of curvature results.
  • FIG. 3 shows a winding in the form of a figure eight.
  • the distance between the two rods 1 corresponds to approximately 1.5 times the diameter of the reactor 2.
  • the reactor has an inlet 3 and an outlet 4, i.e. the medium in the reactor 2 flows in the ascending direction.
  • FIG. 4 shows a further embodiment of a reactor according to the invention. It comprises 6 rods 1, around which a tube 2 with an inlet 3 and an outlet 4 is wound so that a braid is formed around the rods 1, so that a reactor in the form of a palisade wall results.
  • FIG. 5 shows that the winding corresponds to a sinusoidal curve. Ul Ul to t P 1 P "
  • P oi 3 rt rt O P m 3 PO SO P 3 P- P rt ⁇ er 0 ⁇ £ 3 P "p: rt ⁇ 3 ⁇ ⁇ P ⁇ 3 PP P- rt P- a P o P- ⁇ in ⁇ aap: 3 P 1 P- P rt 3 er P- P- er P- PP er a 3 ⁇ ⁇ p: • ⁇ n
  • P 3 P rt G a ⁇ rt P in p: oi ⁇ ⁇ ⁇ 3. 3 ⁇ P ⁇ P ⁇ ⁇ P- P 3 3 * p: er in ⁇ ⁇ P ⁇ P er ⁇ P- 3 a PPP 3 G P- er SO ⁇ ⁇ rt he P oo ⁇ P £ er 3 P er 3 ⁇ ⁇ P- rt w 3 PP 3 O ⁇ ⁇ ⁇ - • PP a P ⁇ V ⁇ m P ⁇ ⁇ PPO 13 P ⁇ ⁇ P P rt rt a ⁇ er 3 • n rt 3
  • Non-polymerizable volatile constituents are generally removed by physical deodorization following the main reactor or by post-polymerization or chemical deodorization.
  • the removal of the volatile constituents which pass into the gas phase reduces the content of these constituents in the dispersion.
  • the physical deodorization can be carried out continuously, for example in a thin-film evaporator or a stripping column (see DE-A-196 21027 and DE-A-197 16 373) or discontinuously, for example in a stirred tank through which a stripping agent flows. Steam is generally used as the stripping agent for the stripping column and the stirred kettle, see e.g. DE-A-12 48 943.
  • the process according to the invention is useful for the production of polymer dispersions with a broad polymer mass fraction.
  • the polymer mass fraction is preferably in the range from 20 to 70, in particular 40 to 60,% by weight.
  • the viscosity of the polymer dispersions can also vary within a wide range. In general, it is less than 800 mPa.s and preferably less than 500 mPa.s (determined according to DIN 53019). It is preferably an essentially monomodal polymer dispersion.
  • the polymer dispersions obtainable according to the invention have a coagulum content of less than 0.5 g / kg polymer, in particular less than 0.3 g / kg polymer.
  • the particle size distribution expressed as
  • 1 50 is generally in the range from 0.1 to 0.4, in particular 0.150 to 0.350. Particle size and particle size distribution were determined using an analytical ultracentrifuge.
  • the test described in the example below was carried out in a reactor made of steel tube (steel number 1.4571) with a length of 100 m, an inner diameter of 10 mm and an outer diameter of 14 mm.
  • the reactor was continuously rising in the form of an equilateral heptagon as shown in FIG. 8.
  • the bending radius was 42 mm.
  • the outer diameter of the overall construction was 312 mm. 18th
  • feed 1 2927 parts of a mixture of 1464 parts of n-butyl acrylate, 1346 parts of methyl methacrylate and 117 parts of acrylic acid (feed 1) and 4382 parts of a mixture of 118 parts of sodium lauryl sulfate, 97 parts of polystyrene seed (33% in water), 47 parts of 10% sodium hydroxide alkali and 4450 parts of water (feed 2) were placed in separate vessels.
  • the two feeds were fed in the specified ratio into a Sulzer SMX, 3 mm, static mixer and pre-emulsified. The emulsion obtained was then heated to 75 ° C.
  • Solids content of the dispersion 39.6% by weight of particle size of the dispersed
  • Coagulate 0.4 g / kg glass transition temperature of the polymer: 25 ° C

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  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
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Abstract

La présente invention concerne un procédé de production en continu d'une dispersion de polymères, dans laquelle les particules dispersées présentent une taille moyenne ≤200 nm, par polymérisation en émulsion radicalaire aqueuse d'au moins un monomère éthyléniquement insaturé, selon lequel on produit une émulsion du monomère ou des monomères dans une phase aqueuse et on polymérise l'émulsion dans un réacteur à écoulement courbé et tubulaire, dont la section est sensiblement circulaire ou ellipsoïdale. Ledit réacteur comporte plusieurs courbes dont les sens de courbure alternent, et une modification du sens de courbure ne se présente au plus tard que lorsque la trajectoire, à partir du début d'une courbe, du centre de gravité de la surface de la section du tube représente 200 fois le diamètre du tube, une courbe pouvant comprendre jusqu'à 3 tours autour de l'axe de courbure. La dispersion de polymères obtenue présente une très faible teneur en coagulat.
PCT/EP1999/001375 1998-03-04 1999-03-03 Procede de production en continu de dispersions de polymeres par polymerisation en emulsion aqueuse WO1999044737A1 (fr)

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DE1998109219 DE19809219A1 (de) 1998-03-04 1998-03-04 Verfahren zur kontinuierlichen Herstellung von Polymerdispersionen durch wässrige Emulsionspolymerisation
DE19809219.9 1998-03-04

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Publication number Priority date Publication date Assignee Title
US6399031B1 (en) 1996-08-26 2002-06-04 Basf Aktiengesellschaft Continuous flow reactor having a plurality of alternating bends

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Publication number Priority date Publication date Assignee Title
DE10150483A1 (de) * 2001-09-28 2003-04-24 Roehm Gmbh Verfahren und Vorrichtung zur Herstellung eines hochmolekularen Poly(meth)acrylats
KR20080055899A (ko) * 2005-09-08 2008-06-19 사이텍 설패이스 스페셜티즈, 에스.에이. 중합체 및 조성물

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WO1994012270A1 (fr) * 1992-11-30 1994-06-09 Universite De Nantes Echangeur melangeur a effet de convection chaotique
EP0636652A1 (fr) * 1993-07-31 1995-02-01 BASF Aktiengesellschaft Masse à mouler thermoplastique d'un copolymère à base d'alkylesters d'acide méthacrylique et un copolymère greffé à cinq étapes en émulsion
EP0768116A1 (fr) * 1995-10-16 1997-04-16 Bayer Ag Réacteur tubulaire modulable à tubes en série placés dans une calandre
EP0818471A1 (fr) * 1996-07-12 1998-01-14 Basf Aktiengesellschaft Procédé de préparation de dispersions aqueuses de polymères à distribution de la taille de particules bimodales
DE19628143A1 (de) * 1996-07-12 1998-01-15 Basf Ag Verfahren zur Herstellung einer wäßrigen Polymerisatdispersion
WO1998008602A1 (fr) * 1996-08-26 1998-03-05 Basf Aktiengesellschaft Dispositif pour effectuer en continu des reactions chimiques

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1994012270A1 (fr) * 1992-11-30 1994-06-09 Universite De Nantes Echangeur melangeur a effet de convection chaotique
EP0636652A1 (fr) * 1993-07-31 1995-02-01 BASF Aktiengesellschaft Masse à mouler thermoplastique d'un copolymère à base d'alkylesters d'acide méthacrylique et un copolymère greffé à cinq étapes en émulsion
EP0768116A1 (fr) * 1995-10-16 1997-04-16 Bayer Ag Réacteur tubulaire modulable à tubes en série placés dans une calandre
EP0818471A1 (fr) * 1996-07-12 1998-01-14 Basf Aktiengesellschaft Procédé de préparation de dispersions aqueuses de polymères à distribution de la taille de particules bimodales
DE19628143A1 (de) * 1996-07-12 1998-01-15 Basf Ag Verfahren zur Herstellung einer wäßrigen Polymerisatdispersion
WO1998008602A1 (fr) * 1996-08-26 1998-03-05 Basf Aktiengesellschaft Dispositif pour effectuer en continu des reactions chimiques

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6399031B1 (en) 1996-08-26 2002-06-04 Basf Aktiengesellschaft Continuous flow reactor having a plurality of alternating bends

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