WO1997007143A1 - Procede de preparation d'une dispersion aqueuse de polymere - Google Patents

Procede de preparation d'une dispersion aqueuse de polymere Download PDF

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Publication number
WO1997007143A1
WO1997007143A1 PCT/EP1996/003339 EP9603339W WO9707143A1 WO 1997007143 A1 WO1997007143 A1 WO 1997007143A1 EP 9603339 W EP9603339 W EP 9603339W WO 9707143 A1 WO9707143 A1 WO 9707143A1
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aqueous
weight
monomers
aqueous polymer
radical
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PCT/EP1996/003339
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German (de)
English (en)
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Johannes Dobbelaar
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Basf Aktiengesellschaft
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Priority to BR9609589A priority Critical patent/BR9609589A/pt
Priority to AU67879/96A priority patent/AU6787996A/en
Publication of WO1997007143A1 publication Critical patent/WO1997007143A1/fr
Priority to MXPA/A/1998/000906A priority patent/MXPA98000906A/xx

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    • 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
    • C08F6/00—Post-polymerisation treatments
    • C08F6/006—Removal of residual monomers by chemical reaction, e.g. scavenging

Definitions

  • the present invention relates to a process for the preparation of an aqueous polymer dispersion, in which an aqueous dispersion of a polymer which contains at least one monomer containing at least one ethylenically unsaturated group in chemically bonded form is incorporated in a manner known per se so that the total content of the aqueous polymer dispersion on free, ie Monomers that are not chemically bonded and have at least one ethylenically unsaturated double bond (referred to in this document as “content of residual monomers” or “residual monomer content”), based on the polymer content of the aqueous polymer dispersion, in the range from> 0 to ⁇ 1% by weight % and then this residual monomer content is reduced by the action of a radical redox initiator system comprising at least one oxidizing agent and at least one reducing agent.
  • a radical redox initiator system comprising at least one oxidizing agent and at least one reducing agent.
  • Aqueous polymer dispersions are fluid systems which, as a disperse phase in an aqueous dispersion medium, contain polymer particles in a stable, disperse distribution.
  • the diameter of the polymer particles is generally mainly in the range from 0.01 to 5 ⁇ m, frequently mainly in the range from 0.01 to 1 ⁇ m.
  • the stability of the disperse distribution often extends over a period of>. 1 month, often even over a period of> 3 months.
  • Their polymer volume fraction based on the total volume of the aqueous polymer dispersion, is normally 10 to 70% by volume.
  • aqueous polymer dispersions have the property of forming polymer films when the aqueous dispersion medium is evaporated, which is why aqueous polymer dispersions are used in many ways as binders, e.g. for paints or compositions for coating leather.
  • a person skilled in the art differentiates between aqueous polymer dispersions and aqueous secondary and aqueous primary dispersions.
  • the aqueous secondary dispersions are those in the preparation of which the polymer is produced outside the aqueous dispersing medium, for example in solution in a suitable non-aqueous solvent. This solution is then transferred to the aqueous dispersing medium and the solvent, generally by distillation, is dispersed. severed.
  • aqueous primary dispersions are those in which the polymer, which is directly in disperse distribution, is itself produced in the aqueous dispersion medium. It is essentially common to all production processes that monomers which have at least one ethylenically unsaturated group are also used to build up the polymer, or that this build-up takes place exclusively from such monomers.
  • Such monomers having at least one ethylenically unsaturated group are usually incorporated by initiated polyreaction, the type of initiation used being determined in particular by the desired application properties of the target product and therefore being adapted to this.
  • initiation for example, an ionic or a radical initiation can be considered.
  • the installation can also be carried out by catalytically initiated polymer-analogous reaction. Radical initiation is used particularly frequently, which is why the incorporation of the at least one monomer having at least one ethylenically unsaturated group is generally carried out by the radical-aqueous emulsion polymerization method in the case of aqueous primary dispersions and generally by the free-radical method in the case of aqueous secondary dispersions Solution polymerization takes place.
  • residual monomers e.g. Acrylonitrile and vinyl acetate
  • EP-A 584 458 it is known to reduce the residual monomer content of aqueous polymer dispersions by stripping with water vapor.
  • EP-B 327 006 recommends the use of conventional distillation.
  • EP-A 505 959 relates to a method for reducing the
  • DE-A 42 10 208 relates to a process for reducing the content of free vinyl acetate and vinyl propionate in aqueous polymer dispersions.
  • the process essentially corresponds to a combined use of stripping and saponification of these monomers, which is why the disadvantages of the aforementioned processes also apply to the process of DE-A 42 10 208.
  • DE-A 30 06 172 relates to a process for reducing the content of free acrylonitrile in aqueous polymer dispersions.
  • additional monomers which are characterized by a pronounced tendency to undergo radical copolymerization with acrylonitrile are added to the aqueous polymer dispersion and the main radical polyreaction is continued.
  • EP-A 379 892 and EP-A 327 006 it is known to determine the residual monomer content of aqueous polymer dispersions by means of radical postpolymerization following the end of the main polyreaction by the action of special ones for which Main polymerization to reduce radical redox initiator systems, which are often less suitable for various reasons.
  • Such redox initiator systems comprise at least one oxidizing agent, at least one reducing agent and optionally one or more transition metal ions occurring in different valence stages.
  • the reducing agent plays a central role in the postpolymerization effectiveness of the radical redox initiator system in aqueous polymer dispersions.
  • the redox initiator system exhibits its advantageous action even at pH values of the aqueous dispersion medium of ⁇ 6 to 10, preferably 7 to 9, since the vast majority of all aqueous polymer dispersions are anionically stabilized,
  • the reducing agent can also develop its effectiveness together with an inorganic oxidizing agent.
  • organic oxidizing agents such as e.g. Organic peroxides or hydroperoxides are usually volatile organic secondary products which are undesirable both for the manufacturer of the aqueous polymer dispersion and for the user of the aqueous polymer dispersion (e.g. R-O-O-H ⁇ R-OH).
  • US-A 4 529 753 recommends in columns 3, 4 reducing sugars and their acid derivatives, e.g. Ascorbic acid and alkali metal disulfite as reducing agents which are suitable in radical redox initiator systems for the purpose of radical postpolymerization in aqueous polymer dispersions, where
  • EP-B 327 006 closes on page 7 of this Recommendation of US Pat. No. 4,529,753 and mentions sulfoxylates, such as the sodium salt of hydroxymethanesulfinic acid (Rongalit®C), as a further suitable reducing agent.
  • a redox initiator system comprising Rongalit C is also used in Example 1 of EP-A 379 892 and in DE-A 38 34 734 for the purpose of radical post-polymerization in an aqueous polymer dispersion.
  • the earlier application DE-A 44 35 422 recommends the use of aminoiminomethanesulfinic acid (formamidinesulfinic acid) as a reducing agent in radical redox initiator systems for removing residual monomers in aqueous polymer dispersions.
  • a disadvantage of this reducing agent is its limited solubility in water. That is, it must be added to the aqueous polymer dispersion containing the residual monomers either as a solid or as a very dilute aqueous solution. Both are disadvantageous when used on an industrial scale.
  • the object of the present invention was therefore to provide a process for reducing the residual monomer content of an aqueous polymer dispersion by the action of at least one
  • a process for reducing the residual monomer content of an aqueous polymer dispersion in which an aqueous dispersion of a polymer which contains at least one monomer having at least one ethylenically unsaturated group in chemically bound form is incorporated in a manner known per se produces that the total content of the aqueous polymer dispersion of free, ie not chemically bound, monomers having at least one ethylenically unsaturated double bond, based on the polymer content of the aqueous polymer dispersion, is in the range from> 0 to ⁇ 1% by weight and accordingly this residual monomer content was reduced by the action of a radical redox initiator system comprising at least one oxidizing agent and at least one reducing agent, which is
  • Electronegativity is above that of the hydrogen atom (cf. HR Christen, Fundamentals of General and Inorganic Chemistry, Sauer Stamm Verlag Arau, p. 72 (1973)), with the exception of those processes in which aqueous monomers containing residual monomers are to be excluded Polymer dispersion the total amount of mercaptan is completely added beforehand by adding the oxidative component of the radical redox initiator system.
  • the process according to the invention can also be used in the range of residual monomer contents of IO " 3 to 0.5% by weight or IO" 3 to 0.1% by weight, based on the polymer content of the aqueous polymer dispersion.
  • Preferred mercaptans to be used according to the invention are mercaptans from the group comprising thiocarboxylic acids having 1 to 8 carbon atoms and their alkali metal and ammonium salts and the thiocarboxylic acids having 1 to 8 carbon atoms and various members of the general formula I
  • Mercaptans on the one hand have a certain water solubility (usually the solubility at 1 bar and 25 ° C ⁇ 1% by weight, based on water; mercaptans to be used according to the invention with such a solubility behavior in water are generally preferred), but on the other hand also in which are able to penetrate more lipophilic polymer particles. Further cheap mercaptans to be used according to the invention are those such as mercaptobenzoic acid, mercaptoacetic acid or mercaptoethanol.
  • Compounds I in which at least one of the radicals R 1 , R 2 , R 3 is additionally hydrogen are particularly suitable according to the invention.
  • Compounds I are furthermore preferred which, in addition to the thiol group, have only one or two of the aforementioned functional groups, among which the carboxyl group, the amino group and the sulfonic acid group are preferred.
  • polymer here includes both polycondensates, e.g. Polyesters, but also polyadducts such as polyurethanes and polymers, which are obtainable by ionic or radical polymerization of monomers which have only at least one ethylenically unsaturated double bond, and also mixed variants of the types mentioned.
  • aqueous polymer dispersion includes both aqueous primary and aqueous secondary dispersions without further addition in this document.
  • Suitable monomers having at least one ethylenically unsaturated group for the process according to the invention are in particular, in a simple manner, radically polymerizable monomers, such as the olefins, for example ethylene, vinylaromatic monomers such as styrene, ⁇ -methylstyrene, o-chlorostyrene or vinyltoluenes, esters of vinyl alcohol and 1 to 18 carbon atoms-containing monocarboxylic acids such as vinyl acetate, vinyl propionate, vinyl n-butyrate, vinyl laurate, vinyl pivalate and vinyl stearate and commercially available monomers VEOVA ® 9-11 (VEOVA X is a trade name of Shell and stands for vinyl esters of carbon ⁇ acids, which are also referred to as Versatic X-acids), esters of ⁇ , ⁇ -monoethylenically unsaturated mono- and dicarboxylic acids, preferably having 3 to 6 carbon atoms,
  • the monomers mentioned In the case of aqueous polymer dispersions produced exclusively by the free-radical aqueous emulsion polymerization method, the monomers mentioned generally form the main monomers which, based on the total amount of the monomers to be polymerized by the free-radical aqueous emulsion polymerization process, normally have a proportion of more than 50 % By weight. As a rule, these monomers have only moderate to low solubility in water under normal conditions (25 ° C., 1 bar).
  • Monomers which have an increased solubility in water under the abovementioned conditions are, for example, ⁇ , ⁇ -mono-ethylenically unsaturated mono- and dicarboxylic acids and their amides, e.g. Acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, acrylamide and methacrylamide, also vinylsulfonic acid and its water-soluble salts and N-vinylpyrrolidone.
  • ⁇ , ⁇ -mono-ethylenically unsaturated mono- and dicarboxylic acids and their amides e.g. Acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, acrylamide and methacrylamide, also vinylsulfonic acid and its water-soluble salts and N-vinylpyrrolidone.
  • the abovementioned monomers which have increased water solubility, are normally only used as modifying monomers in amounts, based on the total amount of the monomers to be polymerized, of less than 50 % By weight, in generally 0.5 to 20, preferably 1 to 10% by weight, polymerized in.
  • Monomers which usually increase the internal strength of the films of the aqueous polymer dispersions normally have at least one epoxy, hydroxy, N-methylol, carbonyl or at least two non-conjugated ethylenically unsaturated double bonds.
  • these are N-alkylolamides of ⁇ , ⁇ -monoethylenically unsaturated carboxylic acids having 3 to 10 carbon atoms and their esters with alkenols having 1 to 4 carbon atoms, among which the N-methylolacrylamide and the N-methylolmethacrylamide are very particularly preferred, two monomers having vinyl radicals, two monomers having vinylidene radicals and two monomers having alkenyl radicals.
  • the di-esters of dihydric alcohols with ⁇ , ⁇ -monoethylenically unsaturated monocarboxylic acids are particularly advantageous, among which acrylic and methacrylic acid are preferred.
  • monomers which have two non-conjugated ethylenically unsaturated double bonds are alkylene glycol diacrylates and dimethacrylates such as ethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,4-butylene glycol diacrylate as well as propylene glycol diacrylate, dibinylbenzene, alla methacrylate malate, vinyl methacrylate malate, vinyl methacrylate malate, vinyl methacrylate malate, vinyl methacrylate malate, vinyl methacrylate malate, vinyl methacrylate malate, vinyl methacrylate malate, vinyl methacrylate malate, vinyl methacrylate malate, vinyl methacrylate malate, vinyl methacrylate malate, vinyl methacrylate malate, methacrylate mal
  • Ci-Cs-hydroxyalkyl esters such as n-hydroxyethyl, n-hydroxypropyl or n-hydroxybutyl acrylate and methacrylate as well as compounds such as diacetone acrylamide and acetylacetoxyethyl acrylate or - methacrylate, ureidoethyl methacrylate and acrylamidoglycolic acid.
  • the above-mentioned monomers are generally also copolymerized in amounts of 0.5 to 10% by weight.
  • the advantage of the uniform lowering of the monomers in the process according to the invention is particularly evident when the residual monomers to be removed comprise two or more than two different monomers having at least one ethylenically unsaturated group. That is, its use proves to be advantageous when three or four or five or six or more different residual monomers are part of the aqueous polymer dispersion to be treated according to the invention.
  • This applies in particular if the residual monomers contained in the aqueous polymer dispersion are such that they have significantly different molar solubilities L in 1000 g of water ( molar solubility in water) under the postpolymerization conditions (these are generally solubilities) essentially identical to those at 25 ° C, 1 bar, approx.).
  • the success according to the invention generally occurs when the residual monomers have at least one residual monomer which, in the list of possible residual monomers, has been assigned to the group of moderately to slightly soluble in water, and at least one residual monomer which is in the corresponding list of Group with increased water solubility was included.
  • One advantage of the process according to the invention is that the reducing agents to be used according to the invention essentially do not result in secondary products which reduce the quality (in particular stability) of aqueous polymer dispersions.
  • This opens up the possibility of simultaneously using the stripping method according to the invention and the stability-stressing stripping method, ie coupling chemical and physical reduction in residual monomers directly, as recommended by US Pat. No. 4,529,753.
  • this fact forms the basis for the fact that the process according to the invention, in contrast to the removal of residual monomers by stripping by means of steam, can be used without difficulty essentially independently of the solids volume content (solids volume, based on the volume of the aqueous polymer dispersion).
  • the solids volume content can be both 10 to 50 and 20 to 60, but also 30 to 70 vol .-%, as is the case, for example, with the aqueous polymer dispersions of DE-A 42 13 965, the applicability at high solids volume concentration ( 50 to 70 vol .-% and higher) particularly interested. It is also advantageous that the method according to the invention can be used with both alkaline and acidic aqueous dispersing medium. This means the application range extends from pH 1 to pH 12.
  • the applicability in the acidic pH range is e.g. of importance if the aqueous polymer dispersion contains 5 5 to 60% by weight of acrylic acid, based on the polymer, in copolymerized form. If the pH of aqueous dispersions of polymers of the abovementioned acrylic acid content is increased, their dynamic viscosity increases considerably. Such aqueous polymer dispersions are therefore advantageously used as thickener dispersions (cf. e.g. DE-PS 11 64 095, DE-PS 12 64 945, DE-PS 12 58 721, DE-PS 15 46 315 and DE-PS 12 65 752). In this regard, they are produced in an acidic medium with a relatively low viscosity.
  • the thickening effect is only brought about by the user by increasing the pH. This is one of the cases in which the residual monomer reduction at the manufacturer of the aqueous polymer dispersion is to be carried out at pH values of the aqueous dispersion medium of below 7 (as a rule ⁇ 7 to 2).
  • the process according to the invention is preferably used at pH values of the aqueous dispersion medium of 6 to 10, particularly preferably 7 to 9. This is for such watery ones
  • aqueous polymer dispersions which are stabilized with the aid of anionic emulsifiers, or which contain, in copolymerized form, ⁇ , ⁇ -monoethylenically unsaturated carboxylic acids such as acrylic acid which have 3 to 6 carbon atoms (generally 0.1 to 5, preferably 0, 5 to 4% by weight, based on the dispersed polymer), in order to stabilize the disperse distribution alone or with others.
  • the redox initiator system according to the invention in the case of the residual monomer reduction according to the invention (even at application temperatures of 20 to 60 ° C.), it is not necessary to use the redox initiator system according to the invention in the presence of a metal compound which is soluble in the aqueous reaction medium and whose metallic component (e.g. iron,
  • Vanadium or their mixture can occur in several valence levels. Of course, use in such a presence is also possible. As a rule, this then takes place in quantities of 0.01 to 1% by weight, based on the oxidizing or reducing agent (the respective deficit component), calculated as the metal compound to be added.
  • these are iron (II) sulfate, iron (II) chloride, Iron (II) nitrate, iron (II) acetate and the corresponding iron (III) salts, ammonium or alkali metal vanadates (V (V)), vanadium (III) chloride, vanadyl (V) trichloride and in particular vanadyl (IV) sulfate Pentahydrate into consideration.
  • 5 complexing agents eg EDTA are often added, which keep the metals in solution under reaction conditions.
  • the working temperature is preferably at least 20, better at least 40, more favorable at least 60, even better at least 80 and very particularly advantageously at least 100 ° C. above the relevant MFT or T g values (this figure should generally be used for post-polymer
  • the process according to the invention can be used both under an inert gas atmosphere (for example N 2 , Ar) and under an atmosphere containing oxygen (for example air).
  • an inert gas atmosphere for example N 2 , Ar
  • an atmosphere containing oxygen for example air
  • the process according to the invention is particularly applicable to those aqueous polymer dispersions whose dispersed polymer, minus the residual monomer removal according to the invention, according to the free radical aqueous emulsion polymerization method from at least one ethylenically
  • the addition is carried out by continuous addition (generally as a pure monomer feed or pre-emulsified in the aqueous phase) in such a way that at least 80, preferably at least 90 and very particularly preferably at least 95% by weight of the Polymerization located monomers are polymerized.
  • aqueous seed polymer dispersions can also be used to adjust the particle size of the dispersed polymer particles (cf. EP-B 40419 and Encyclopedia of Polymer Science and Technology, Vol. 5, John Wiley & Sons Inc., New York (1966) p. 847).
  • Free radical polymerization initiators for the main polymerization reaction described above are all those which are capable of initiating a free radical aqueous emulsion polymerization. It can be both peroxides and azo compounds. Of course, redox initiator systems can also be used.
  • the radical initiator system used for the main polymerization will be different from the radical initiator system to be used for the post-polymerization according to the invention. In general, at least 50% by weight, more often at least 75% by weight and mostly at least 90% by weight of the monomers to be polymerized in the course of the main polymerization are polymerized without the presence of the reducing agent according to the invention. In other words, the main polymerization will normally not comprise a reducing agent according to the invention.
  • radical aqueous emulsion polymerization As the main polyreaction particularly efficiently from the point of view of the desired properties and with regard to high economy, the use of peroxodisulfuric acid and / or its alkali metal salts and / or their ammonium salt as radical initiators is preferred.
  • 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.
  • the manner in which the free-radical initiator system is added to the polymerization vessel in the course of the free-radical aqueous emulsion main polymerization described is rather of orderly meaning.
  • the initiator system can either be completely introduced into the polymerization vessel or, depending on its consumption, can be added continuously or in stages in the course of the free-radical aqueous emulsion polymerization. In detail, this depends in a manner known per se to the person skilled in the art both on the chemical nature of the initiator system and on the polymerization temperature.
  • reaction temperature for the above-mentioned radical aqueous emulsion main polymerization is the entire range from 0 to 100 ° C, temperatures from 70 to 100 ° C, preferably 80 to 100 ° C and particularly preferably> 85 to 100 ° C, however, are preferably used.
  • the application of increased or reduced pressure is possible, so that the polymerization temperature can also exceed 100 ° C and can be up to 130 ° C or more.
  • Volatile monomers such as ethylene, butadiene or vinyl chloride are preferably polymerized under elevated pressure. It is of course possible to use substances which regulate the molecular weight, such as tert, in the course of the radical aqueous main emulsion polymerization. -Dodecyl mercaptan or the reducing agents according to the invention.
  • Emulsion polymerization dispersants used which ensure the stability of the aqueous polymer dispersion produced.
  • Both the protective colloids usually used to carry out free-radical aqueous emulsion polymerizations and emulsifiers come into consideration as such.
  • Suitable protective colloids are, for example, polyvinyl alcohols, cellulose derivatives or copolymers containing vinylpyrrolidone.
  • 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 to 420.
  • mixtures of emulsifiers can also be used and / or protective colloids are used.
  • emulsifiers are used as dispersants, the relative molecular weights of which, in contrast to the protective colloids, are usually below 1000. They can be of anionic, cationic or non-ionic nature.
  • anionic emulsifiers are with one another and with non-ionic ones Emulsifiers compatible.
  • cationic emulsifiers while anionic and cationic emulsifiers are usually incompatible with one another.
  • Common emulsifiers are, for example, ethoxylated mono-, di- and tri-alkylphenols (EO degree: 3 to 100, alkyl radical: C 4 to C ⁇ 2 ), ethoxylated fatty alcohols (EO degree: 3 to 100, alkyl radical: Cs to C ⁇ 8 ), as well as alkali and ammonium salts of alkyl sulfates (alkyl radical: Cs to Cig), of sulfuric acid semiesters of ethoxylated alkanols (EO degree: 1 to 70, alkyl radical: C i2 to Cis) and ethoxylated alkylphenols (EO degree: 3 to 100, alkyl radical: C 4 to C ⁇ 2 ), of alkyl sulfonic acids (alkyl radical: C 12 to Cis) and of alkylarylsulfonic acids (alkyl radical: Co.
  • EO degree: 3 to 100, alkyl radical: C 4 to C ⁇ 2 eth
  • R 1 and R 2 are hydrogen or C 4 - to C 24 -alkyl and are not simultaneously hydrogen, and X and Y can be alkali metal ions and / or ammonium ions.
  • R 1 and R 2 are preferably linear or branched alkyl radicals having 6 to 18 carbon atoms or hydrogen, and in particular having 6, 12 and 16 carbon atoms, where R 1 and R 2 are not both hydrogen at the same time .
  • X and Y are preferably sodium, potassium or ammonium ions, with sodium being particularly preferred.
  • Compounds I in which X and Y are sodium, R 1 is a branched alkyl radical having 12 C atoms and R 2 is hydrogen or R 1 are particularly advantageous.
  • the compounds I are preferably used as dispersants in the process according to the invention on their own and particularly preferably in a mixture with ethoxylated fatty alcohols (EO degree: 3 to 50, alkyl radical: Cs to C 36 ).
  • the compounds I are generally known, for example from US Pat. No. 4,269,749, and are commercially available.
  • the amount of dispersant used is 0.5 to 6, preferably 1 to 3,% by weight, based on the monomers to be polymerized radically.
  • the aforementioned dispersants are generally suitable for stabilizing the immediate process products according to the invention.
  • the immediate process products according to the invention also include aqueous polymer dispersions of self-emulsifying polymers, i.e. of polymers which have ionic groups which are able to effect stabilization due to the repulsion of charges of the same sign.
  • the direct process products according to the invention preferably have anionic stabilization (in particular anionic dispersants).
  • aqueous polymer dispersion whose residual monomer content is to be reduced in the manner according to the invention is prepared by the free-radical aqueous emulsion polymerization method from monomer compositions of monomers having at least one ethylenically unsaturated group
  • monomer compositions which are particularly important with regard to the process according to the invention are those which comprise at least two monomers which differ from one another and have at least one ethylenically unsaturated group, and for the rest
  • esters of acrylic and / or methacrylic acid with alkanols and / or styrene having 1 to 12 carbon atoms 70 to 99.9% by weight of esters of acrylic and / or methacrylic acid with alkanols and / or styrene having 1 to 12 carbon atoms,
  • monomer compositions which comprise: 0.1 to 5% by weight of at least one ⁇ , ⁇ -monoethylenically unsaturated carboxylic acid and / or its amide (monomers A) and having 3 to 6 carbon atoms and
  • esters of acrylic and / or methacrylic acid with alkanols and / or styrene having 1 to 12 carbon atoms 10 60 to 99.9% by weight of esters of acrylic and / or methacrylic acid with alkanols and / or styrene having 1 to 12 carbon atoms.
  • the method 15 according to the invention is very particularly recommendable, however, in the case of free-radical aqueous emulsion polymerizations of monomer compositions which comprise:
  • acrylonitrile preferably 0.5 to 15% by weight
  • esters of acrylic and / or methacrylic acid with alkanols and / or styrene having 1 to 12 carbon atoms 59.9 to 99.9% by weight of esters of acrylic and / or methacrylic acid with alkanols and / or styrene having 1 to 12 carbon atoms.
  • the monomer compositions mentioned are preferably selected such that the T g values of the resulting dispersed polymers are below 50 ° C., preferably below 25 ° C. and very particularly preferably below 0 ° C. (up to -70 ° C.).
  • aqueous polymer dispersions containing residual monomers the dispersed polymer of which is produced from monomers having at least one ethylenically unsaturated group after the free radical aqueous emulsion polymerization
  • the 1% by weight limit will generally be reached within the framework of this radical aqueous main emulsion polymerization achieve or fall below residual monomers based on the entire aqueous dispersion.
  • the process according to the invention for lowering the residual monomers can either be used immediately afterwards or, until the aforementioned limit has been reached, first of all by the methods known per se for reducing the residual monomers of the prior art, before proceeding according to the invention in order to take advantage of the method according to the invention.
  • the main polyreaction and the step of lowering the residual monomers according to the invention can merge seamlessly.
  • the free radical redox initiator system according to the invention may also have been used in the course of the main polyreaction.
  • the free radical redox initiators to be used according to the invention can also contain other reducing agents such as reducing sugars, e.g. Glucose and fructose, derivatives thereof such as ascorbic acid or sulfinic acids such as hydroxymethanesulfinic acid or alkylsulfinic acids such as iso-propylsulfinic acid (or salts thereof).
  • reducing sugars e.g. Glucose and fructose
  • derivatives thereof such as ascorbic acid or sulfinic acids such as hydroxymethanesulfinic acid or alkylsulfinic acids such as iso-propylsulfinic acid (or salts thereof).
  • the reducing agents according to the invention preferably form more than 50, preferably more than 75% by weight of the total amount of reducing agents used, and very particularly preferably they form the sole reducing agent.
  • the oxidative constituent of the radical redox initiators to be used according to the invention are, for example, molecular oxygen, ozone, agents which give off oxygen and form radicals without a peroxide structure, such as alkali metal chlorates and perchlorates, Transition metal oxide compounds such as potassium permanganate, manganese dioxide and lead oxide, but also lead tetraacetate and iodobenzene into consideration.
  • peroxides, hydroperoxides or mixtures thereof are preferably used.
  • Hydrogen peroxide (especially in combination with mercaptoethanol), peroxodisulfuric acid and their salts, in particular their alkali metal salts (i.e. Na and K), alkali perborates, peroxodiphosphates, have been found to be favorable.
  • alkali metal salts i.e. Na and K
  • alkali perborates i.e. Na and K
  • peroxodiphosphates alkali metal salts
  • -Butyl hydroperoxide and others have been proven. According to the invention, preference is given to using exclusively inorganic oxidizing agents, since in combination with the reducing agents according to the invention this enables emission-free chemical post-deodorization.
  • Oxidizing agents and reducing agents should generally be used in a molar ratio of 1: 1 to 5: 1 in the process according to the invention. They are preferably used in approximately equivalent amounts.
  • the radical redox initiator system to be used according to the invention can in principle be added all at once to the aqueous polymer dispersion containing the residual monomers.
  • the oxidizing agent can also be added all at once and the reducing agent can then be fed in continuously.
  • the feed takes place synchronously.
  • the supply is expediently carried out in the form of aqueous solutions.
  • the amounts of the radical redox initiator system to be used according to the invention naturally depend on the amount of residual monomers still present and their desired degree of reduction.
  • the amount to be used will be from 0.01 to 5% by weight, advantageously from 0.1 to 1% by weight, based on the dispersed polymer or on about 10 times the amount by weight of the residual monomers.
  • the radical redox initiator systems to be used according to the invention enable an effective reduction in residual monomers in a short time.
  • the residual monomer contents determined in the following examples are based on gas chromatographic determinations.
  • aqueous polymer dispersion treated according to the invention was mixed with 1 g of a solution of 300 mg of dioxane (standard) in 1 kg of water. Then 5 .mu.l of the aqueous polymer dispersion thus diluted were placed in a tightly closable container with an internal volume of 22 ml and kept at 150.degree. C. for 15 minutes in the sealed container. The gas phase of the container interior was then analyzed by gas chromatography. This was done using a medium polar "fused silica capillary column DB-1" from J & W Scientific Folsom, USA. In all of the examples according to the invention, the content of volatile organic secondary products was below the detection limit of 5 ppm (parts by weight, based on the dispersion).
  • an aqueous polymer stabilized with 0.1% by weight Dowfax 2A1 and 0.1% by weight Na lauryl sulfate (the amount stated in each case based on the polymer) - Dispersion generated (number-average polymer particle diameter 150 nm), the solids content of which was 50% by weight.
  • Gas chromatographic analysis of the aqueous polymer dispersion showed a residual monomer content of 7000 ppm (weight, based on the dispersion) n-Btuylacrylat.
  • the aqueous polymer dispersion was then examined gaschro ⁇ matically for the remaining free n-butyl acrylate content and for volatile organic secondary products (including the reducing agent used itself).
  • the results obtained are shown in Table 1 below as a function of the reducing agent used. It additionally shows the result when using H 2 0 2 alone and when using only reducing agents.

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  • 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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Abstract

Selon ce procédé de préparation d'une dispersion aqueuse de polymère, on prépare de façon connue en soi une dispersion aqueuse d'un polymère qui contient au moins un monomère chimiquement lié avec au moins un groupe éthyléniquement insaturé, de sorte que la teneur totale de la dispersion aqueuse de polymère en monomères libres, c'est-à-dire non chimiquement liés et pourvus d'au moins une liaison double éthyléniquement insaturée, soit supérieure à 0 et égale ou inférieure à 1 % en poids, par rapport à la teneur en polymère de la dispersion aqueuse de polymère. Cette teneur résiduelle en monomères est ensuite réduite au moyen d'un système initiateur d'oxydoréduction radicalaire qui comprend au moins un agent oxydant et au moins un agent réducteur. Le système initiateur d'oxydoréduction contient comme agent réducteur un mercaptane qui contient, en plus du groupe mercaptane, au moins un autre groupe fonctionnel.
PCT/EP1996/003339 1995-08-11 1996-07-29 Procede de preparation d'une dispersion aqueuse de polymere WO1997007143A1 (fr)

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BR9609589A BR9609589A (pt) 1995-08-11 1996-07-29 Processo para preparação de uma dispersão aquosa de polímero
AU67879/96A AU6787996A (en) 1995-08-11 1996-07-29 Process for preparing an aqueous polymer dispersion
MXPA/A/1998/000906A MXPA98000906A (en) 1995-08-11 1998-02-02 Procedure for the obtaining of aqueous dispersions of polimeriz

Applications Claiming Priority (2)

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DE19529599.4 1995-08-11
DE1995129599 DE19529599A1 (de) 1995-08-11 1995-08-11 Verfahren zur Herstellung einer wäßrigen Polymerisatdispersion

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CA (1) CA2224287A1 (fr)
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DE (1) DE19529599A1 (fr)
TW (1) TW334450B (fr)
WO (1) WO1997007143A1 (fr)

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CN1113901C (zh) * 1997-09-18 2003-07-09 巴斯福股份公司 通过加入一种氧化还原引发剂体系降低液体体系中残余单体的方法
KR100461709B1 (ko) * 2001-04-12 2004-12-14 미쯔이가가꾸가부시끼가이샤 5'-보호된 2'-데옥시푸린 뉴클레오사이드 정제 방법
WO2015147179A1 (fr) * 2014-03-27 2015-10-01 横浜ゴム株式会社 Composition de caoutchouc et pneu l'utilisant

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DE19741187A1 (de) * 1997-09-18 1999-03-25 Basf Ag Verfahren zur Verminderung des Restmonomerengehalts in wässrigen Polymerdispersionen
DE19839199A1 (de) 1998-08-28 2000-03-02 Basf Ag Verfahren zur Verminderung der Restmonomerenmenge in wässrigen Polymerdispersionen
DE19840586A1 (de) 1998-09-05 2000-03-09 Basf Ag Verfahren zur Verminderung der Restmonomerenmenge in wässrigen Polymerdispersionen
DE10317434A1 (de) 2003-04-15 2004-10-28 Basf Ag Verfahren zur Reduzierung der Restmonomerenmenge in wässrigen Polymerdispersionen
DE10335958A1 (de) 2003-08-04 2005-02-24 Basf Ag Verfahren zur Herstellung wässriger Polymerisatdispersionen
DE102005054904A1 (de) 2005-11-17 2007-05-24 Wacker Polymer Systems Gmbh & Co. Kg Verfahren zur Herstellung polyvinylalkoholstabilisierter Latices
US9249247B2 (en) 2009-11-16 2016-02-02 Dsm Ip Assets B.V. Acrylic polymer
EP2646486A1 (fr) 2010-12-02 2013-10-09 DSM IP Assets B.V. Polymère acrylique
WO2014161817A1 (fr) 2013-04-03 2014-10-09 Basf Se Procédé de réduction de la quantité de monomère résiduelle dans une dispersion polymère aqueuse
EP2965785A1 (fr) 2014-07-11 2016-01-13 DSM IP Assets B.V. Nouvelle utilisation
US11834590B2 (en) 2017-12-22 2023-12-05 Stratasys, Inc. Adhesive compositions and their use in 3D printing

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EP0080969A1 (fr) * 1981-11-23 1983-06-08 The Goodyear Tire & Rubber Company Méthode pour éliminer de l'acrylonitrile résiduaire d'un système latex
US4766173A (en) * 1987-05-11 1988-08-23 Nalco Chemical Company Method for reducing residual acrylic acid in acrylic acid polymer gels
EP0391147A2 (fr) * 1989-03-24 1990-10-10 Herberts Gesellschaft mit beschränkter Haftung Procédé de traitement de systèmes aqueux renfermant des composés insaturés polymérisables par voie radicalaire
WO1996010588A1 (fr) * 1994-10-04 1996-04-11 Basf Aktiengesellschaft Procede de preparation de dispersions aqueuses de polymere

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Publication number Priority date Publication date Assignee Title
US3974117A (en) * 1973-11-02 1976-08-10 Hoechst Aktiengesellschaft Process for the manufacture of aqueous copolymer dispersions
EP0080969A1 (fr) * 1981-11-23 1983-06-08 The Goodyear Tire & Rubber Company Méthode pour éliminer de l'acrylonitrile résiduaire d'un système latex
US4766173A (en) * 1987-05-11 1988-08-23 Nalco Chemical Company Method for reducing residual acrylic acid in acrylic acid polymer gels
EP0391147A2 (fr) * 1989-03-24 1990-10-10 Herberts Gesellschaft mit beschränkter Haftung Procédé de traitement de systèmes aqueux renfermant des composés insaturés polymérisables par voie radicalaire
WO1996010588A1 (fr) * 1994-10-04 1996-04-11 Basf Aktiengesellschaft Procede de preparation de dispersions aqueuses de polymere

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1113901C (zh) * 1997-09-18 2003-07-09 巴斯福股份公司 通过加入一种氧化还原引发剂体系降低液体体系中残余单体的方法
KR100461709B1 (ko) * 2001-04-12 2004-12-14 미쯔이가가꾸가부시끼가이샤 5'-보호된 2'-데옥시푸린 뉴클레오사이드 정제 방법
WO2015147179A1 (fr) * 2014-03-27 2015-10-01 横浜ゴム株式会社 Composition de caoutchouc et pneu l'utilisant
JP2015189833A (ja) * 2014-03-27 2015-11-02 横浜ゴム株式会社 ゴム組成物及びこれを用いる空気入りタイヤ

Also Published As

Publication number Publication date
AR003228A1 (es) 1998-07-08
AU6787996A (en) 1997-03-12
TW334450B (en) 1998-06-21
CA2224287A1 (fr) 1997-02-27
CO4560473A1 (es) 1998-02-10
DE19529599A1 (de) 1997-02-13
BR9609589A (pt) 1999-02-23
MX9800906A (es) 1998-05-31

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