EP1756183A1

EP1756183A1 - Method for producing polymers that are predominantly formed from vinyl formamide

Info

Publication number: EP1756183A1
Application number: EP05737094A
Authority: EP
Inventors: Maximilian Angel; Lysander Chrisstoffels; Claudia Wood
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 2004-05-04
Filing date: 2005-04-22
Publication date: 2007-02-28
Also published as: DE102004022256A1; US20070197767A1; CN100523026C; WO2005108445A1; JP2007536419A; CN1950407A

Abstract

The invention relates to a method for producing polymers that are predominantly formed from vinyl formamide and that contain a small amount of residual vinyl formamide monomers. Said method comprises the radical polymerisation of: (a) 49.9 - 99.9 wt. % N-vinyl formamide; (b) 0 - 50 wt. % of one or more radically polymerisable monomers; (c) 0.1 - 5 wt. % of at least one monomer from the group containing N-vinyl pyrrolidone, N-vinyl-N-methyl-acetamide, N-vinyl caprolactam and N-vinyl piperidone, whereby the monomer (c) is only added for the polymerisation when the fraction of monomer (a) that has not yet been polymerised is < 5 wt. %.

Description

Process for the production of polymers predominantly composed of vinylformamide

The present invention relates to a process for the preparation of polymers composed predominantly of vinylformamide, and to the use of the polymers produced by this process.

State of the art

WO 99/25745 describes a process for reducing the N-vinylformamide monomer content in corresponding polymers, a so-called scavenger from the group of the oxidizing agents, reducing agents, Grignard reagents, alkali metal cyanides and ammonia derivatives being added to the polymer before the hydrolysis.

EP 870782 A2 describes polymers with a reduced residual monomer content, which are obtained by a certain combination of a detergent / diluent (diluent), such as ethyl acetate and acetone, with an initiator.

EP 1031585 describes copolymers of vinylformamide with a low residual monomer content, obtainable by a process by lowering the pH by 2 to 5 units between the start and end of the polymerization.

WO 2001002450 describes the production of a polymer by using vinylformamide as a comonomer. Subsequent treatment of the polymer with hydrogen peroxide lowers the residual monomer content.

DE 19836992 describes a process for eliminating formamide from polymers with N-vinylformamide units by treating the polymer with acid or base.

task

The object was therefore to provide a process for the radical polymerization of polymers composed predominantly of vinylformamide, which process provides polymers with a significantly lower vinylformamide residual monomer content compared to the polymers prepared by known processes.

Description of the invention

We have found a process for the preparation of predominantly vinylformamide-based polymers with a low vinylformamide residual monomer content by (a) 49.9-99.9% by weight of N-vinylformamide, (b) 0-50% by weight of one or more free-radically polymerizable monomers, (c) 0.1-5% by weight of at least one monomer from the group consisting of N-vinylpyrrolidone, N-vinyl-N-methylacetamide, N-vinyl caprolactam and N-vinyl piperidone is formed, radical polymerized, the monomer (c) being added to the polymerisation only when the proportion of unpolymerized monomer (a) is <5% by weight.

The process according to the invention is suitable for the production of polymers from 49.9 to 99.9% by weight, preferably from 60 to 98% by weight, particularly preferably from 75 to 95% by weight, very particularly preferably from 80 to 90% by weight .-% N-vinylformamide. In the following, vinylformamide is used synonymously with N-vinylformamide or with the abbreviation VFA, unless expressly stated otherwise.

Suitable monomers (b) are the N-vinylimidazole derivatives of the general formula (I), in which R ¹ to R ^{3 are} hydrogen, -CC ₄ -alkyl or phenyl

Diallylamines of the general formula (II) in which R ^{4 is} C ₁ -C ₂ 4-alkylene are also suitable

Also suitable are N, N-dialkylaminoalkyl acrylates and methacrylates and N, N-dialkylaminoalkyl acrylamides and methacrylamides of the general formula (III),

where R ⁵ , R ⁶ independently represent a hydrogen atom or a methyl radical, R ^{7 represents} an alkylene radical having 1 to 24 carbon atoms, optionally substituted by alkyl radicals and R ⁸ , R ^{9 represents} CC ₂ 4 alkyl radicals. Z stands for a nitrogen atom together with x = 1 or for an oxygen atom together with x = 0.

Examples of compounds of the general formula (I) can be found in the following Table 1:

Table 1

Me = methyl Ph = phenyl

Further useful monomers of the formula (I) are the ethyl, propyl or butyl analogs of the methyl-substituted 1-vinylimidazoles listed in Table 1.

Examples of compounds of the general formula (II) are diallylamines in which R ^{4 represents} methyl, ethyl, iso- or n-propyl, iso-, n- or tert-butyl, pentyl, hexyl, heptyl, octyl, nonyl or decyl , Examples of longer-chain radicals R ⁴ are undecyl, dodecyl, tridecyl, pentadecyl, octadecyl and icosayl. Examples of compounds of the general formula (III) are

N, N-dimethylaminomethyl (meth) acrylate,

N, N-diethylaminomethyl (meth) acrylate,

N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate,

N, N-dimethylaminobutyl (meth) acrylate,

N, N-diethylaminobutyl (meth) acrylate,

N, N-DimethylaminohexyI (meth) acrylate,

N, N-dimethylaminooctyl (meth) acrylate, N, N-dimethylaminododecyl (meth) acrylate,

N- [3- (dimethylamino) propyl] methacramide,

N- [3- (dimethylamino) propyl] acrylamide,

N- [3- (dimethylamino) butyl] methacryIamid,

N- [8- (dimethylamino) octyI] methacrylic amide, N- [12- (dimethylamino) dodecyl] methacrylamide,

N- [3- (diethylamino) propyl] methacrylamide,

N- [3- (diethylamino) propyl] acr lamide.

Preferred examples of monomers (b) are 3-methyl-1-vinylimidazolium chloride and methosulfate, dimethyldiallylammonium chloride and N, N-dimethylaminoethyl methacrylate and N- [3- (dimethylamino) propyl] methacrylic amide, which are produced by methyl chloride, dimethyl sulfate or diethyl sulfate were quaternized.

The monomers (b) can either be used in quaternized form as monomers or polymerized non-quaternized, in which case the polymer obtained is either quaternized or protonated.

For the quaternization of the compounds of the general formulas (I) to (III), for example alkyl halides with 1 to 24 carbon atoms in the alkyl group, e.g. Methyl chloride, methyl bromide, methyl iodide, ethyl chloride, ethyl bromide, propyl chloride, hexyl chloride, dodecyl chloride, lauryl chloride and benzyl halides, especially benzyl chloride and benzyl bromide. Other suitable quaternizing agents are dialkyl sulfates, especially dimethyl sulfate or diethyl sulfate. The quaternization of the basic monomers of the general formulas (I) to (III) can also be carried out with alkylene oxides such as ethylene oxide or propylene oxide in the presence of acids.

The quaternization of the monomer or a polymer with one of the quaternizing agents mentioned can be carried out by generally known methods.

Preferred quaternizing agents are: methyl chloride, dimethyl sulfate or diethyl sulfate. The quaternization of the polymer can be carried out completely or only partially. The proportion of quaternized monomers (a) in the polymer can vary over a wide range and is, for example, about 20 to 100 mol%.

For protonation, for example, mineral acids such as HCI, H ₂ S0 ₄ , H ₃ PO ₄ , as well as monocarboxylic acids, such as formic acid and acetic acid, dicarboxylic acids and polyfunctional carboxylic acids, such as oxalic acid and citric acid, as well as all other proton donating compounds and substances in the Are able to protonate the corresponding vinylimidazole or diallylamine. Water-soluble acids are particularly suitable for protonation.

Protonation is understood to mean that at least some of the protonatable groups of the polymer, preferably 20 to 100 mol%, are protonated, so that a total cationic charge of the polymer results.

Suitable monomers (b) are CrC ₄₀ alkyl esters of (meth) acrylic acid, the esters being derived from linear, branched-chain or carbocyclic alcohols, for example methyl (meth) acrylate, ethyl (meth) acrylate, tert-butyl (meth) acrylate, isobutyl (meth) acrylate, n-butyl (meth) acrylate, stearyl (meth) acrylate, or esters of alkoxylated fatty alcohols, eg dC ^ o-fatty alcohols, reacted with ethylene oxide, propylene oxide or butylene oxide , in particular C ₁₀ -C ₁₈ fatty alcohols, reacted with 3 to 150 ethylene oxide. units: N-alkyl-substituted acrylamides with linear, branched-chain or carbocyclic alkyl radicals, such as N-tert.-butylacrylamide, N-butylacrylamide, N-octylacrylamide, N-tert.-octylacrylamide, are also suitable.

Also suitable are styrene, vinyl and allyl esters of CC ₄ o-carboxylic acids, which can be linear, branched or carbocyclic, for example vinyl acetate, vinyl propionate, vinyl neononanoate, vinyl neoundecanoic acid, t-butyl-benzoic acid vinyl ester, alkyl vinyl ether, for example methyl vinyl ether, ethyl vinyl ether, butyl vinyl ether , Stearyl vinyl ether.

Acrylamides, such as N-tert-butylacrylamide, N-butylacrylamide, N-octylacrylamide, N-tert.-octylacrylamide and N-alkyl-substituted acrylamides with linear, branched-chain or carbocyclic alkyl radicals, the alkyl radical having the meanings given above for R ⁴ can.

Suitable monomers (b) are in particular C 1 to C ₂₄ -, very particularly C 1 to C ₁₀ . Alkyl esters of (meth) acrylic acid, for example methyl (meth) acrylate, ethyl (meth) acrylate, tert-butyl (meth) acrylate, isobutyl (meth) acrylate, n-butyl (meth) acrylate and acrylamides such as N-tert.- Butylacrylamide or N-tert-octylacrylamide.

Particularly suitable monomers (b) are acrylamide, methacrylamide, N, N-dimethylacrylamide, N-methylol methacrylamide, N-vinyloxazolidone, N-vinyltriazole, Hydroxyalkyl (meth) acrylic! Ate, for example hydroxyethyl (meth) acrylate and hydroxypropyl (meth) acrylates, or alkyl ethylene glycol (meth) acrylates with 1 to 50 ethylene glycol units in the molecule.

Also suitable are N-vinylimidazoles of the general formula (I) in which R ¹ to R ^{3 are} hydrogen, CC ₄ alkyl or phenyl, diallylamines of the general formula (II), and also dialkylaminoalkyl (meth) acrylates and dialkylaminoalkyl (meth) acrylamides of the general formula (III), for example dimethylaminoethyl methacrylate or dimethylaminopropyl methacrylamide.

Unsaturated carboxylic acids and unsaturated anhydrides, e.g. Acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid or their corresponding anhydrides as well as unsaturated sulfonic acids, e.g. Acrylamido methyl propane sulfonic acid, and the salts of the unsaturated acids, such as e.g. the alkali or ammonium salts.

The monomer (b) is used in an amount of up to 50% by weight, preferably up to 30% by weight, particularly preferably up to 25% by weight, in the process according to the invention.

However, the process is also particularly suitable for the production of polymers which, apart from vinylformamide and the monomer (c), have no further monomer units polymerized in them.

Monomers (c) for the process according to the invention are 0.1-5% by weight, preferably 0.3-4% by weight, particularly preferably 1-3% by weight, of one or more monomers from the group N-vinylpyrrolidone, N-vinyl-N-methylacetamide, N-vinylacetamide, N-vinylcaprollactam, N-vinylpiperidone are suitable.

N-vinylpyrrolidone is particularly suitable as monomer (c).

The preparation of the polymers can be carried out according to the processes of free-radically initiated polymers known per se, e.g. by solution polymerization, emulsion polymerization, suspension polymerization, precipitation polymerization, reverse suspension polymerization or reverse emulsion polymerization, without the methods which can be used being restricted thereto.

A preferred polymerization process for the process according to the invention is solution polymerization or water-in-water polymerization (W W polymerization). The process according to the invention is advantageously carried out by polymerizing the monomers (a) and, if desired (b), together with a radical initiator, for example by a batch or feed process. Towards the end of the polymerization, ie at a point in time at which less than 5% by weight, preferably less than 3% by weight, particularly preferably less than 1% by weight, of the monomer (a) is still present in the polymerization reaction, the monomer (s) is added. The weight percent refers to the total weight of the polymer.

If several monomers (c) are to be added, these can be added individually or premixed to the polymerization reaction.

In a preferred embodiment of the present invention, no further starting materials are added to the reaction mixture. However, the present invention also encompasses processes in which further starting materials, such as, for example, regulators, emulsifiers, protective colloids and / or salt, are added to the reaction mixture. The water-soluble and water-insoluble peroxo and / or azo compounds customary for this purpose can be used as initiators for the radical polymerization, for example alkali metal or ammonium peroxydisulfates, dibenzoyl peroxide, tert-butyl perpivalate, tert-butyl per-2-ethylhexanoate, di- tert-butyl peroxide, tert-butyl hydroperoxide, azo-bis-isobutyronitrile, azo-bis (2-amidinopropane) dihydrochloride 2,2'-Az, o-bis (2-methylbutyronitrile). Initiator mixtures or redox initiator systems, such as e.g. Ascorbic acid / iron (II) sulfate / sodium peroxodisulfate, tert-butyl hydroperoxide / sodium disulfite, tert-butyl hydroperoxide / sodium hydroxymethanesulfinate. The initiators can be used in the customary amounts, for example 0.05 to 5% by weight, based on the amount of the monomers to be polymerized.

The molecular weight and the K value of the polymers can be varied within a wide range in a manner known per se through the choice of polymerization conditions, for example polymerization duration, polymerization temperature or initiator concentration, and through the content of crosslinking agent and regulator.

The polymerization can be carried out in the presence of a regulator (e). Connections with high transmission constants are referred to as regulators (polymerization regulators). Regulators accelerate chain transfer reactions and thus reduce the degree of polymerization of the resulting polymers without affecting the gross reaction rate.

Regarding the regulators, one can differentiate between mono-, bi- or polyfunctional regulators depending on the number of functional groups in the molecule, which can lead to one or more chain transfer reactions. Suitable controllers are described in detail, for example, by KC Berger and G. Brandrup in J. Brandrup, EH Immergut, Polymer Handbook, 3rd ed., John Wiley &. Sons, New York, 1989, pp. 11/81 - 11/141.

Suitable regulators are, for example, aldehydes such as formaldehyde, acetaldehyde, propionaldehyde, n-butyraldehyde and isobutyraldehyde.

The following can also be used as regulators: formic acid, its salts or esters, 2,5-diphenyl-1-hexene, ammonium formate, hydroxylammonium sulfate, and hydroxylammonium phosphate.

Other suitable regulators are halogen compounds such as alkyl halides, such as carbon tetrachloride, chloroform, bromotrichloromethane, bromoform, allyl bromide, and benzyl compounds, such as benzyl chloride or benzyl bromide.

Other suitable regulators are allyl compounds, e.g. Allyl alcohol, functional allyl ethers, such as allyl ethoxylates, alkyl allyl ethers, or glycerol monoallyl ethers.

Compounds which contain sulfur in bound form are preferably used as regulators.

Compounds of this type are, for example, inorganic hydrogen sulfites, disulfites and dithionites or organic sulfides, disulfides, polysulfides, sulfoxides, sulfones. The following regulators are mentioned by way of example: di-n-butyl sulfide, di-n-octyl sulfide, diphenyl sulfide, thiodiglycol, ethylthioethanol, diisopropyl disulfide, di-n-butyl disulfide, di-n-hexyl disulfide, diacetyl disulfide, diethanol sulfide, di-t-butyl trisulfide Dimethyl sulfoxide, dialkyl sulfide, dialkyl disulfide and / or diaryl sulfide.

Organic compounds which contain sulfur in bound form are particularly preferred.

Compounds which are preferably used as polymerization regulators are thiols (compounds which receive sulfur in the form of SH groups, also referred to as mercaptans). Mono-, bi- and polyfunctional mercaptans, mercapto alcohols and / or mercaptocarboxylic acids are preferred as regulators.

Examples of these compounds are allyl thioglycolates, ethyl thioglycolate, cysteine, 2-mercaptoethanol, 1,3-mercaptopropanol, 3-mercaptopropan-1, 2-diol, 1,4-mercaptobutanol, mercaptoacetic acid, 3-mercaptopropionic acid, mercapto-succinic acid, thio-acetic acid, thio-acetic acid , Thiourea and alkyl mercaptans such as n-butyl mercaptan, n-hexyl mercaptan or n-dodecyl mercaptan.

Particularly preferred thiols are cysteine, 2-mercaptoethanol, 1, 3-mercaptopropanol, 3-mercaptopropan-1,2-diol, thioglycerol, thiourea. Examples of bifunctional regulators which contain two sulfur in bound form are bifunctional thiols, such as, for example, dimercaptopropanesulfonic acid (sodium salt), dimercaptosuccinic acid, dimercapto-1-propanol, dimercaptoethane, dimercaptopropan, dimercaptobutane, dimercaptopentane, dimercaptohexane, ethylene glycol bis ethylene glycol and butanediol bis-thioglycolate.

Examples of polyfunctional regulators are compounds which contain more than two sulfur in bound form. Examples of this are trifunctional and / or tetrafunctional mercaptans.

Preferred trifunctional regulators are trifunctional mercaptans, e.g. Trimethylolpropane tris (2-mercaptoethanate, Trimethylolpropane tris (3-mercaptopropionate), Trimethylolpropane tris (4-mercaptobutanate), Trimethylolpropane tris (5-mercapto-pentanate), Trimethylolpropane tris (6-mercaptohexanate), Trimethylolpropane tris (2-mercaptohexanate) ,

Glyceryl thioglycolate, glyceryl thiopropionate, glyceryl thioethylate, glycerylthiobutanate.

1,1,1-propanetriyl tris (mercaptoacetate), 1,1,1-propanetriyl tris (mercaptoethanate), 1, 1, 1-propanetrjy! tris-r (mercaptoproprionate), 1, 1, 1-propanetriyl tris (mercaptobutanate).

2-hydroxmethyl-2-methyl 1, 3-propanediol tris (mercaptoacetate), 2-hydroxmethyl-2-methyl-1, 3-propanediol tris (mercaptoethanate), 2-hydroxmethyl-2-methyl-1, 3- propanediol tris (mercaptopropionate), 2-hydroxymethyl-2-methyl-1, 3-propanediol tris (mercapto-butanate).

Trifunctional controllers are particularly preferred

Glyceryl thioglycolate, trimethylolpropane tris (2-mercaptoacetate, 2-hydroxmethyl-2-methyl-1, 3-propanediol tris (mercaptoacetate).

Preferred tetrafunctional mercaptans are pentaerythritol tetraquis (2-mercaptoacetate)

Pentaerythritol tetraquis (2-mercaptoethanate), pentaerythritol tetraquis (3-mer captopropionate), pentaerythritol tetraquis (4-mercaptobutanate), pentaerythritol tetraquis (5-mercaptopentanate), pentaerythritol tetraquisan (6-mercapto).

Si compounds which are formed by reacting compounds of the formula (IVa) are suitable as further polyfunctional regulators. Si compounds of the formula (IVb) are also suitable as polyfunctional regulators. (Z— O) ₃ . _n - Si - R ² - SH (IVa)

(Z— 0) _3- „- Si - R ² - S— (IVb) in which n is a value from 0 to 2, R ^{1 is} a CrC ^ alkyl group or phenyl group, R ^{2 is} a CrC ₁₈ alkyl group, the cyclohexyl or denotes phenyl group, Z represents a CrCι ₈ alkyl group, C ₂ -C ₁₈ alkylene group or C ₂ -C ₁₈ alkynyl group, the carbon atoms of which may be replaced by non-adjacent oxygen or halogen atoms, or one of the groups

in which R ₃ denotes a C 1 -C ₁₂ alkyl group and R ₄ denotes a C 1 -C ₈ alkyl group.

All of the controllers mentioned can be used individually or in combination with one another.

Furthermore, crosslinkers, i.e. Compounds with at least 2 ethylenically unsaturated, non-conjugated double bonds in the molecule are added.

Suitable crosslinkers are, for example, acrylic esters, methacrylic esters, allyl ethers or vinyl ethers of at least dihydric alcohols. The OH groups of the underlying alcohols can be wholly or partially etherified or esterified; however, the crosslinkers contain at least two ethylenically unsaturated groups.

Examples of the underlying alcohols are dihydric alcohols such as 1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 2,3-butanediol, 1,4-butanediol , But-2-en-1,4-diol, 1,2-pentanediol, 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,10-decanediol, 1,2-dodecanediol, 1 , 12-dodecanediol, neopentyl glycol, 3-methylpentane-1,5-diol, 2,5-dimethyl-1,3-hexanediol, 2,2 ₎ 4-trimethyl-1,3-pentanediol, 1,2- Cyclohexanediol, 1,4-cyclohexanediol, 1,4-bis (hydroxymethyl) cyclohexane, hydroxypivalinic acid neopentyl glycol monoester, 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis [4- (2-hydroxypropyl) phenyl] propane, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, 3-thio-pentane-1, 5-diol, and also polyethylene glycols, polypropylene glycols and polytetrahydrofuran with molecular weights of 200 to 10000 propylene in addition to the homopolymer block copolymers of ethylene oxide or propylene oxide or copolymers which contain ethylene oxide and propylene oxide groups incorporated can also be used. Examples of underlying alcohols with more than two OH groups are trimethylolpropane, glycerol, pentaerythritol, 1,2,5-pentanetriol, 1,2,6-hexanetriol, triethoxycyanuric acid, sorbitan, sugars such as sucrose, glucose, mannose. Of course, the polyhydric alcohols can also be used as the corresponding ethoxylates or propoxylates after reaction with ethylene oxide or propylene oxide. The polyhydric alcohols can also first be converted into the corresponding glycidyl ethers by reaction with epichlorohydrin.

Further suitable crosslinkers are the vinyl esters or the esters of monohydric, unsaturated alcohols with ethylenically unsaturated C ₃ to C ₆ carboxylic acids, for example acrylic acid, methacrylic acid, itaconic acid, maleic acid or fumaric acid. Examples of such alcohols are allyl alcohol, 1-buten-3-ol, 5-hexen-1-ol, 1-octen-3-ol, 9-decen-1-ol, dicyclopentenyl alcohol. 10-undecen-1-ol, cinnamon alcohol, citronellol, crotyl alcohol or cis-9-octadecen-1-ol. However, the monohydric, unsaturated alcohols can also be esterified with polybasic carboxylic acids, for example malonic acid, tartaric acid, trimellitic acid, phthalic acid, terephthalic acid, citric acid or succinic acid.

Other suitable crosslinkers are esters of unsaturated carboxylic acids with the polyhydric alcohols described above, for example oleic acid, crotonic acid, cinnamic acid or 10-undecenoic acid.

Also suitable as crosslinking agents are straight-chain or branched, linear or cyclic, aliphatic or aromatic hydrocarbons which have at least two double bonds which must not be conjugated to aliphatic hydrocarbons, e.g. Divinylbenzene, divinyltoluene, 1, 7-octadiene, 1, 9-decadiene, 4-vinyl-1-cyclohexene, trivinylcyclohexane or polybutadienes with molecular weights from 200 to 20,000.

Also suitable as crosslinking agents are acrylic acid amides, methacrylic acid amides and N-allylamines of at least divalent amines. Such amines are, for example, 1,2-diaminomethane, 1,2-diaminoethane, 1,3-diaminopropane, 1,4-diaminobutane, 1,6-diaminohexane, 1, 12-dodecanediamine, piperazine, diethylenetriamine or isophoronediamine. The amides of allylamine and unsaturated carboxylic acids are also suitable such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, or at least dibasic carboxylic acids as described above.

Triallylamine and triallylmonoalkylammonium salts, e.g. Triallylmethylammonium chloride or methyl sulfate, suitable as a crosslinking agent.

N-vinyl compounds of urea derivatives, at least divalent amides, cyanurates or urethanes, for example of urea, ethylene urea, propylene urea or tartaric acid diamide, e.g. N, N'-divinyl ethylene urea or N, N'-divinyl propylene urea.

Other suitable crosslinkers are divinyl dioxane, tetraallylsilane or tetravinylsilane.

Of course you can too. Mixtures of the aforementioned compounds are used. Those crosslinkers which are soluble in the monomer mixture are preferably used.

A detailed description of suitable protective colloids can be found in Houben-Weyl, Methods of Organic Chemistry, Volume XIV / 1, Macromolecular Substances, Georg-Thier e-Verlag, Stuttgart, 1961,, 3. 411 to 420.

Both anionic, cationic and nonionic emulsifiers are suitable as emulsifiers. Preferably, only accompanying emulsifiers are used as accompanying surface-active substances, the molecular weights of which, in contrast to the protective colloids, are usually below 2000 g / mol. Of course, if mixtures of surface-active substances are used, the individual components must be compatible with one another, which can be checked by means of a few preliminary tests if in doubt. Anionic and nonionic emulsifiers are preferably used as surface-active substances. Common accompanying emulsifiers are, for example, ethoxylated fatty alcohols (EO grade: 3 to 50, alkyl radical: C ₈ - to C ₃₆ ), ethoxylated mono-, di- and tri-alkylphenols (EO degree: 3 to 50, alkyl radical: C ₄ - to C ₉ ), alkali metal salts of dialkyl esters of sulfosuccinic acid and alkali and ammonium salts of alkyl sulfates (alkyl radical: C ₈ - to C ₁₂ ), of ethoxylated alkanols (EO grade: 4 to 30, alkyl radical: C ₁₂ - to C ₁₈ ), of ethoxylated alkylphenols (EO grade: 3 to 50, alkyl radical: C ₄ - to C ₉ ), of alkyl sulfonic acids (alkyl radical: C ₁₂ - to C- | ₈ ) and of alkylarylsulfonic acids (alkyl radical: C ₉ - to C ₁₈ ).

Suitable emulsifiers can also be found in Houben-Weyl, Methods of Organic Chemistry, Volume 14/1, Macromolecular Substances, Georg Thieme Verlag, Stuttgart, 1961, pages 192 to 208. Trade names of emulsifiers are e.g. Dowfax® 2 A1, Emulan® NP 50, Dextrol® OC 50, Emulsifier 825, Emulsifier 825 S, Emulan® OG, Texapon® NSO, Nekanil® 904 S, Lumiten® l-RA, Lumiten E 3065 etc ,

The surface-active substance is usually used in amounts of 0.1 to 10% by weight, based on all monomers to be polymerized.

In a preferred embodiment of the process according to the invention, an acidic hydrolysis step is carried out after the polymerization. For this purpose, the polymer is adjusted to a pH between 4 and 6, preferably between 4.5 and 5.5, using suitable acids.

Suitable acids for the acidic hydrolysis step are inorganic acids such as sulfuric acid or hydrochloric acid and organic acids such as formic acid, lactic acid, acetic acid.

The acidic hydrolysis is preferably carried out at temperatures in the range between 40 and 150 ° C., preferably between 50 and 120 ° C., particularly preferably between 60 and 90 ° C. Depending on the temperature, a period of 1 hour to 24 hours is required for the acid hydrolysis.

The polymer can then be neutralized and isolated.

The polymers predominantly composed of vinylformamide can also be converted into the corresponding polymers carrying amine units by subsequent alkaline hydrolysis (amide cleavage). In particular if cationic or cationizable polymers are desired for certain applications, such a complete or partial hydrolysis step is recommended in which all or part of the formamide units are hydrolyzed to the amine.

Alkali hydroxides, in particular sodium hydroxide solution and potassium hydroxide solution, are suitable for such an alkaline hydrolysis step.

The polymers produced by the process according to the invention can advantageously be used in the field of cosmetics, in particular hair cosmetics, and also for producing cellulose-containing products, in particular paper and cardboard. For example:

Preparation of polymer A according to the invention (W / W polymerization):

VFA / DADMAC / VP 80 parts / 20 parts / 2.25 parts

used abbreviations

NaOH sodium hydroxide

Pluriol E 1500 polyethylene glycol with average molecular weight 1500 g / mol (from BASF)

Kollidon 90 F polyvinylpyrrolidone with a K value of 90 (from BASF)

Kollidon 17 PF polyvinylpyrrolidone with a K value of 17 (from BASF)

DADMAC N.N-diallyldimethylammonium chloride

WakoV-50 2,2'-azobis (2-amidino-propane) dihydrochloride (from Wako)

VP vinyl pyrrolidone

Conc.

Presentation 517.72 g demineralized water 100.00% 2.0Q g sodium dihydrogen phosphate x H20 100.00% 0.48 g NaOH (10% in water) 10.00% 179.90 g Plurjql E 1509. 100.00% 6.00 g Kolidon 90 F 100.00% 6.00 g Kollidon 17 PF 100.00%

Addition 01 66.70 g DADMAC (60% in water) 60.00% 160.00 g vinylformamide 100.00%

Inlet 01 3.40 g Wako V-50 100.00% 30.60 g DI water 100.00%

Inlet 02 4.50 g vinyl pyrone lidon 100.00% 22.20 g demineralized water ^< 100.00%

Apparatus: 2 I cervical spine

Driving style: The feed materials of the template are filled into the apparatus and inertized with nitrogen overnight. Then the addition 1 is added to the template via a funnel and homogenized. The pH is checked and, if necessary, adjusted to pH 6.8 using 25% sodium hydroxide solution. The apparatus is heated to 55 ° C. at a stirrer speed (anchor stirrer) of 180 rpm. A portion of feed 1 (5.0 g) is added at 53 ° C. and the mixture is polymerized for 10 minutes. Then 19 g of feed 1 are metered in over 2.5 hours and then polymerized at 55 ° C. for 2 hours. Then the feed 2 is metered in in 1 h and polymerized for 1 h at 55 ° C. Then it is heated to 75 ° C. At 72 ° C 10 g of feed 1 are metered in in 1 hour. After the end of feed 1, polymerization is continued for a further 3 hours at 75.degree. Finally, it is cooled to room temperature (approx. 23 ° C).

analytics:

Appearance slightly yellowish, viscous, emulsion-like, solid content 40% by weight

Vinyl formamide 50 ppm

Vinyl pyrrolidone 10 ppm

Comparative Example B

Preparation of Comparative Copolymer B:

VFA DADMAC 80 parts / 20 parts

Koriz.

Template 517.72 g demineralized water 100.00% 2.00 g sodium dihydrogen phosphate x H20 100.00% 0.48 g NaOH (10% in water) 10.00% 179.90 g Pturiol E 1500 100.00% 6.00 g Kollidon 90 F 100.00% 6.00 g Kollidorr 17 PF 100.00%

Addition 01 66.70 g 'DADMAC (60% in water) 60.00% 160.00 g vinylformamide 100.00%

Inlet 01 3.40 g Wako V-50 100.00% 30.60 g DI water 100.00%

Apparatus: 2 I cervical spine

Driving style: The feed materials of the template are filled into the apparatus and inertized with nitrogen overnight. Then the addition 1 is added to the template via a funnel and homogenized. The pH is checked and, if necessary, adjusted to pH 6.8 using 25% sodium hydroxide solution. The apparatus is heated to 55 ° C. at a stirrer speed (anchor stirrer) of 180 rpm. A portion of feed 1 (5.0 g) is added at 53 ° C. and the mixture is polymerized for 10 minutes. Then 19 g of feed 1 are metered in over 2.5 hours and then polymerized for 4 hours at 55 ° C. Then it is heated to 75 ° C. At 72 ° C 10 g of feed 1 are metered in in 1 hour. After the end of feed 1, polymerization is continued for a further 3 hours at 75.degree. Finally, it is cooled to room temperature (approx. 23 ° C).

analytics:

Appearance slightly yellowish, viscous, emulsion-like, solid content 40.5%

Vinyl formamide 240 ppm

Claims

claims

1. A process for the preparation of predominantly vinylformamide-containing polymers with a low vinylformamide residual monomer content by (a) 49.9-99.9% by weight of N-vinylformamide, (b) 0-50% by weight of one or several radically polymerizable monomers, (c) 0.1-5% by weight of at least one monomer from the group formed by N-vinylpyrrolidone, N-vinyl-N-methylacetamide, N-vinylcaprollactam and N-vinylpiperidone, polymerized by free radicals , wherein the monomer (c) is only added to the polymerization when the proportion of unpolymerized monomer (a) is <5% by weight.

2. The method according to claim 1, characterized in that the monomer (c) is only added to the polymerization when the proportion of unpolymerized monomer (a) is <2% by weight.

3. The method according to claim 1, characterized in that the monomer (c) is only added to the polymerization when the proportion of unpolymerized monomer (a) is <0.5% by weight.

4. The method according to claim 1, characterized in that an acidic hydrolysis takes place after the polymerization.

5. The method according to claim 4, characterized in that the acidic hydrolysis takes place at pH values between 4 and 6.

6. Use of the polymers produced by a process according to claims 1 to 5 for cosmetics.

7. Use of the polymers produced by a process according to claims 1 to 5 for the production of cellulose-containing products.