CA1262995A - Preparation of polymer powders - Google Patents
Preparation of polymer powdersInfo
- Publication number
- CA1262995A CA1262995A CA000520638A CA520638A CA1262995A CA 1262995 A CA1262995 A CA 1262995A CA 000520638 A CA000520638 A CA 000520638A CA 520638 A CA520638 A CA 520638A CA 1262995 A CA1262995 A CA 1262995A
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- Prior art keywords
- weight
- vinyl
- carbon dioxide
- parts
- vinylformamide
- Prior art date
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Classifications
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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
- C08F2/00—Processes of polymerisation
- C08F2/04—Polymerisation in solution
- C08F2/06—Organic solvent
-
- 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
- C08F26/00—Homopolymers and copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a single or double bond to nitrogen or by a heterocyclic ring containing nitrogen
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/50—Improvements relating to the production of bulk chemicals
- Y02P20/54—Improvements relating to the production of bulk chemicals using solvents, e.g. supercritical solvents or ionic liquids
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- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
Abstract
O.Z. 0050/38062/38063 Abstract of the Disclosure. Polymer powders are prepared by polymerizing N-vinylcarboxamides, water-soluble esters of ethylenically unsaturated carboxylic acids, N-vinylimi-dazoles or N-vinylimidazolines or by copolymerizing N-vinylformamide with N-vinylpyrrolidone or vinyl acetate in supercritical carbon dioxide under superatmospheric pressure and with thorough mixing in the presence of a free radical initiator, from 100 to 1500 parts by weight of carbon dioxide being used per 100 parts by weight of monomer.
Description
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- 1 - o.Z~ 0050/38062/38063 Preparation of polymer powders Polymer po~ders can be prepared by polymerizing monomers by various methods, for example by precip;tation polymerization or reverse suspension polymerization or in a powder bed. In every case, a diluent is required. In the preparation of water-soluble homopolymer powders, for e~ample, aliphatic or aromatic hydrocarbons are used as diluents. In polymerization in a fixed bed, inert liq-uids are required as boiling aids, or a large excess of a readily volatile monomer is used ;n order to remove the heat evolved during polymerization~ Inert liqu;ds used dur;ng the polymerizat;on have to be removed from the poly-mers or recavered. The removal of small amounts of aro-matic hydrocarbons or halohydrocarbons from water-soluble polymers ;s regarded as part;cularly difficult.
U.S. Patent 4,250,331 discloses that carbo~ylic acids can be recovered from dilute aqueous soLutions of alkali metal salts of carboxylic acids by treat;ng the sa;d aqueous solutions at from 35 to 200C and under from 80 to 500 atm ~ith a supercr;tical liquid which contains not less than 10 mol % of carbon dioxide. Under ~he re-action conditions9 the salt of the carboxylic acid ;s con-verted to the free carboxyL;c acid, which dissolves ;n the supercrit;cal liquid and is isolated from this by low-ering the pressure.
U.S. Patent 3,5Z2,228 discloses a process for thepreparation of polymers, ;n which ethylenically unsatu-rated monomers are subjected to homopolymerization or co-polymerization in the presence of a catalyst or under the action of high energy radiat;on in l;qu;d carbon diox;de at from -7~ to 100C under superatmospher;c pressure.
The polymers are obtained in the form of coarse powders or viscous o;ls, from which they are precipitated by treat-ment with liquids ;n which the polymers are insoluble.
It ;s an object of the presen~ invention to pro-vide a process which permits the preparation o~ particu-larly fineLy divided polymer powd-ers by polymerization of :~2~
- 1 - o.Z~ 0050/38062/38063 Preparation of polymer powders Polymer po~ders can be prepared by polymerizing monomers by various methods, for example by precip;tation polymerization or reverse suspension polymerization or in a powder bed. In every case, a diluent is required. In the preparation of water-soluble homopolymer powders, for e~ample, aliphatic or aromatic hydrocarbons are used as diluents. In polymerization in a fixed bed, inert liq-uids are required as boiling aids, or a large excess of a readily volatile monomer is used ;n order to remove the heat evolved during polymerization~ Inert liqu;ds used dur;ng the polymerizat;on have to be removed from the poly-mers or recavered. The removal of small amounts of aro-matic hydrocarbons or halohydrocarbons from water-soluble polymers ;s regarded as part;cularly difficult.
U.S. Patent 4,250,331 discloses that carbo~ylic acids can be recovered from dilute aqueous soLutions of alkali metal salts of carboxylic acids by treat;ng the sa;d aqueous solutions at from 35 to 200C and under from 80 to 500 atm ~ith a supercr;tical liquid which contains not less than 10 mol % of carbon dioxide. Under ~he re-action conditions9 the salt of the carboxylic acid ;s con-verted to the free carboxyL;c acid, which dissolves ;n the supercrit;cal liquid and is isolated from this by low-ering the pressure.
U.S. Patent 3,5Z2,228 discloses a process for thepreparation of polymers, ;n which ethylenically unsatu-rated monomers are subjected to homopolymerization or co-polymerization in the presence of a catalyst or under the action of high energy radiat;on in l;qu;d carbon diox;de at from -7~ to 100C under superatmospher;c pressure.
The polymers are obtained in the form of coarse powders or viscous o;ls, from which they are precipitated by treat-ment with liquids ;n which the polymers are insoluble.
It ;s an object of the presen~ invention to pro-vide a process which permits the preparation o~ particu-larly fineLy divided polymer powd-ers by polymerization of :~2~
- 2 - o.z~ OOSO/38062/38063 the mono~ers in a diluent which is physiologically accep-table and from which the polymers can easily be removeda We have found that this object is achieved, accor-ding to the invention, by a Drocess for the preparation of polymer powders by polymerizing ethylenically unsatur-ated compounds in carbon dioxide under superatmospheric pressure in the presence of a free radical initiator and vaporizing the carbon dioxide, if an N-v;nylcarboxamide, , a ~ater-soluble ester of an ethylenically unsaturated carboxylic acid, an N-v;nyllactamO an N-vinylimidazole or an N-vinylimidazoline is homopolymerized or N-vinylfor~-amide is copolymerized with N-vinylpyrroli~one or vinyl acetate, as the ethylenically unsaturated co~mpound~ the polymer;zation being carried out in each case in supercri-tical carbon dioxide with thorough mixing at about 31-150C under a pressure above 73 bar, and from 100 to 1500 parts by ~eight of carbsn d;oxide are employed per 100 parts by weight of monomer.
Examples of N-vinylcarboxamides which are suitable for the prepara~ion of homopolymers are monomers which are derived from N-vinylcarboxamides of saturated C1~C6-carboxylic acids, eg~ N-vinylformamide, N-vinyl-N-methyl-formamide, N-vinylacetamide, N-vinyl-N-methylacetamide, N-vinylpropionamide, N-vinyl-N-methyLpropionamide, N-vinylbut-Z5 yramide and N-vinyl capronamide, and suitable N-vinyllactams, eg. N-vinylpyrrolidone and N-vinylcaprolactam.
Another group of monomers from which industrially usefuL homopolymers are prepared comprises water-soluble esters of monoethylenically unsaturated carboxylic acids.
The water-soluble esters of ethylenically unsaturated C3 Cs-; carboxylic acids are preferably used. The water-soluble esters of ethylenically unsaturated carboxylic acids are derived either from aminoalcohsls or from glycols or poly-glycols, only one OH group of the glycols and polyglycoLs in each case being esterified ~ith an ethylenically unsatu-rated carboxylic acid.
Examples of suitable esters of this type are
Examples of N-vinylcarboxamides which are suitable for the prepara~ion of homopolymers are monomers which are derived from N-vinylcarboxamides of saturated C1~C6-carboxylic acids, eg~ N-vinylformamide, N-vinyl-N-methyl-formamide, N-vinylacetamide, N-vinyl-N-methylacetamide, N-vinylpropionamide, N-vinyl-N-methyLpropionamide, N-vinylbut-Z5 yramide and N-vinyl capronamide, and suitable N-vinyllactams, eg. N-vinylpyrrolidone and N-vinylcaprolactam.
Another group of monomers from which industrially usefuL homopolymers are prepared comprises water-soluble esters of monoethylenically unsaturated carboxylic acids.
The water-soluble esters of ethylenically unsaturated C3 Cs-; carboxylic acids are preferably used. The water-soluble esters of ethylenically unsaturated carboxylic acids are derived either from aminoalcohsls or from glycols or poly-glycols, only one OH group of the glycols and polyglycoLs in each case being esterified ~ith an ethylenically unsatu-rated carboxylic acid.
Examples of suitable esters of this type are
- 3 - O.Z. 0050/3806Z/3~063 di-C1-C3-alkylamino-C2-C6-alkyl (meth)acrylates, such as d;methylaminoethyl acrylate, dimethylaminoethyl meth-acrylate, die~hylaminoethyl methacrylate, dipropylamino-ethyl acrylate, dimethylaminopropyl acrylate, dimethyl-aminopropyl methacrylate, dimethylaminobutyl acrylate, di-methylaminobutyl methacrylate, dimethylaminopentyl acry-late, dimethylam;noneopentyl methacrylate and dimethyl-aminohexyl acrylate. The basic acrylates are employed in the form of the free bases, in the form of ~he salts with mineral acids, eg~ hydrochloric acid or sulfuric acid, or in quaternized form (examples of suitable quaternizing agents are dimethyl sulfate, methyl chloride, e~hyl chlor-ide and benzyl chloride).
Examples of suitable esters of glycols, polygly-cols or polyhydric alcohols, of which only one hydroxyl group is esterified in each case, are hydroxyethyl acry-late~ hydroxyethyl methacrylate, monoesters of acrylic acid with polyalkylene glycols ha~ing a molecular weight of from 1500 to 10,00U in a molar ratio of 1:1, the cor-responding methacrylatPs, and esters of acrylic acid andmethacrylic acid with block copolymers of ethylene oxide and propylene oxide in which the molar ratio of ethyleni-cally unsaturated carboxylic acid to alcohoL is 1:1. The salts or quaternization products of the basic esters and the hydroxyalkyl esters of the ethylenically unsaturated carboxylic acids form homopolymers which dissolve in water.
The homopolymers of N-vinylpyrrolidone and of N-vinylcap-rolactam are also water-soluble.
Other suitable monomers for the novel process for the preparation of homopolymers are N-vinylimidazole and substituted N-vinylimidazoles, eg. N-vinyl-2-methylimi dazole, N-vinyl-4-methylimidazole, N-vinyl-5-methylimida-zole~ N-vinyl-2-ethylimidazole, N-vinyl-2-propylimidazole and N-vinyl-2-isopropylimidazole~ and N-vinylimidazolines, such as N-vinylimidazoline, N-vinyl 2-methylimidazoline, N-vinyl-2-ethylimidazoline, N-vinyl-2-isopropylimidazoline, N-vinyl-2-n-propylimidazoline and N-vinyl-2-phenylimida70line.
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Examples of suitable esters of glycols, polygly-cols or polyhydric alcohols, of which only one hydroxyl group is esterified in each case, are hydroxyethyl acry-late~ hydroxyethyl methacrylate, monoesters of acrylic acid with polyalkylene glycols ha~ing a molecular weight of from 1500 to 10,00U in a molar ratio of 1:1, the cor-responding methacrylatPs, and esters of acrylic acid andmethacrylic acid with block copolymers of ethylene oxide and propylene oxide in which the molar ratio of ethyleni-cally unsaturated carboxylic acid to alcohoL is 1:1. The salts or quaternization products of the basic esters and the hydroxyalkyl esters of the ethylenically unsaturated carboxylic acids form homopolymers which dissolve in water.
The homopolymers of N-vinylpyrrolidone and of N-vinylcap-rolactam are also water-soluble.
Other suitable monomers for the novel process for the preparation of homopolymers are N-vinylimidazole and substituted N-vinylimidazoles, eg. N-vinyl-2-methylimi dazole, N-vinyl-4-methylimidazole, N-vinyl-5-methylimida-zole~ N-vinyl-2-ethylimidazole, N-vinyl-2-propylimidazole and N-vinyl-2-isopropylimidazole~ and N-vinylimidazolines, such as N-vinylimidazoline, N-vinyl 2-methylimidazoline, N-vinyl-2-ethylimidazoline, N-vinyl-2-isopropylimidazoline, N-vinyl-2-n-propylimidazoline and N-vinyl-2-phenylimida70line.
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- 4 - o~Z~ 0050/38062/3~063 N-vinylimida~oles and N-vinylimidazolines are em-ployed not only in the -form of the free bases but also in a form which is neutralized with a mineral acid or in quaternized form, quaterization preferably being effected with dimethyl sulfate, benzyl chloride, methyl chloride or ethyl chloride.
The homopolymers are preferably prepared starting from N-vinylformamide, N-vinyl-N-methylformamide, N-vinyl-pyrrolidone, hydroxyethyl acrylate, hydroxyethyl methacry-late, dimethylaminoethyl acrylate, dimethylaminoethylmethacrylate or diethylaminoethyl acrylate. The basic monomers may also be used in the form of the salt with a strong mineral acid or in quaternized form.
Copolymers of N-vinylformamide and N-vinylpyrro-lidone and those of N-vinylformamide and vinyl acetate are of industrial importance. N-Yinylformamide and N-vinylpyrrolidone can be copolymerized in any ratio. Co-polymers of N-vinylformamide and vinyl acetate are pre-pared by copolymerization of a monomer mixture which con-tains not more than 90, preferably from 5 to 60, ~ by~eight of vinyl acetate. All monomers are preferably used in anhydrous form in the polymer;zation.
The polymerizat;on is carried out under super-atmospheric pressure in supercritical carbon d;oxide as an inert diluent. The properties of carbon dioxide in the liquid state and in the supercritical state have been reported by J.A. Hyatt, J. Org. Chem. 49 (1984), 5097-5101.
According to this publication~ the critical point of car-bon dioxide occurs at about 31C and 73 bar. The homo-polymerization and copolymerization of the above monomersare carried out in supercritical carbon dioxidQ at above about 31C, the critical temperature of carbon dioxide.
The upper limit for the preparation of the polymers is the temperature which is 10C below the point at which the particuLar polymers formed begin to softenO The upp~r temperature limit is 150C. Homopolymerization and copoly-meriza~;on are preferably carried out a~ from 40 to 130C,
The homopolymers are preferably prepared starting from N-vinylformamide, N-vinyl-N-methylformamide, N-vinyl-pyrrolidone, hydroxyethyl acrylate, hydroxyethyl methacry-late, dimethylaminoethyl acrylate, dimethylaminoethylmethacrylate or diethylaminoethyl acrylate. The basic monomers may also be used in the form of the salt with a strong mineral acid or in quaternized form.
Copolymers of N-vinylformamide and N-vinylpyrro-lidone and those of N-vinylformamide and vinyl acetate are of industrial importance. N-Yinylformamide and N-vinylpyrrolidone can be copolymerized in any ratio. Co-polymers of N-vinylformamide and vinyl acetate are pre-pared by copolymerization of a monomer mixture which con-tains not more than 90, preferably from 5 to 60, ~ by~eight of vinyl acetate. All monomers are preferably used in anhydrous form in the polymer;zation.
The polymerizat;on is carried out under super-atmospheric pressure in supercritical carbon d;oxide as an inert diluent. The properties of carbon dioxide in the liquid state and in the supercritical state have been reported by J.A. Hyatt, J. Org. Chem. 49 (1984), 5097-5101.
According to this publication~ the critical point of car-bon dioxide occurs at about 31C and 73 bar. The homo-polymerization and copolymerization of the above monomersare carried out in supercritical carbon dioxidQ at above about 31C, the critical temperature of carbon dioxide.
The upper limit for the preparation of the polymers is the temperature which is 10C below the point at which the particuLar polymers formed begin to softenO The upp~r temperature limit is 150C. Homopolymerization and copoly-meriza~;on are preferably carried out a~ from 40 to 130C,
- 5 - o.Z. 0050/38062/38063 in particular from 70 to 130C~ The pressures are greater than 73 bar, pre~erably from 80 to 300 bar.
The polymerization reaction is initiated with the aid of free radical polymerization initiators. Any ini-S tiators which are conventionally used for polymerizingthe monomers in question may be employed. Examples of suitable free radical initiators are those which have a half life of less than 3 hours at the temperatures selec-- ted. If the polymerization is carried out at two dif-ferent temperatures, initial polymerization o~ the mono-mers first being carried out at a low temperature and poly-merization then being completed at a substantially higher temperature, it ;s a~antageous to use two or more differ-ent initiators which have an adequate rate of decomposi-tion in the particular temperature range selected. Forexample~ the following initiators can be used ;n the tem- ~
perature ranges stated below:
Temperature: 40-60C
Acetylcyclohexanesul~onyl peroxide, diacetyl peroxidi-carbonate, dicyclohexyl peroxidicarbonate, di-Z-ethyl-hexyl peroxidicarbonate, tert-butyl perneodecanoate and 2~2'-azobis-(4-methoxy-2,4-dimethylvaleronitrile).
Temperature: 60-80C
- tert-8utyl perpivalate, dioctanoyl peroxide, dilauroyl peroxide, Z,2'-azobis-~2,4-dimethylvaleronitrile) and tert-butylazo-2-cyanobutane.
Temperature: R0 100C
Dibenzoyl peroxide, tert-butyl per-2-ethylhexanoate, tert-butyl permaleate and 2,2-azobisisobutyronitrile.
Temperature: 100-120C
bis-(tert-8utylperoxi)-cyclohexane, tert-butylperoxiiso-propyl carbonate and tert-butyl peracetate.
Temperature: 120-140C
2,2-bis-(ter~-Butylperoxi)-but3ne, dicumyl peroxide, di-tert-amyl peroxide and di-tert-butyl peroxide.
TempPrature: 140-160C
p-Menthane hydroperoxide, pinane hydroperoxide, cumene ~ 6 - o.Z~ 0050/38062/38063 hydroperoxide and tert-butyl hydroperoxide.
8y using redox coini~iators, for example benzoin, dimethylaniline and complexes and salts of heavy metals, such as copper, cobalt, manganese, iron, nickel and chrom-ium, ~hich are soluble in organic solvents, it is pos-sible to reduce the half l;ves of the stated peroxides, in particular the hydroperoxides~ so that, for example, tert-butyl hydroperoxide in the presence of 5 ppm of cop-per(II) acetylacetonate is effective at as low as 100C.
The polymerization initiators are used in the con-ventional amounts for polymerization; for example, from 0.05 to 10, preferably from 0.1 to 5 parts by weight of an initiator are required per 100 parts by weight of the monomers.
The polymerization can~ if required, also be car-ried out in the presence of polymerization regulators to regulate the molecular weight of the polymers. Where it is desired to prepare copolymers having a particularly lou molecular weight, larger amounts of polymerization regulators are used, whereas only small amounts of these regulators are ~mployed for the preparation of h;gh mole-cular weight copolymers, or the polymerization is çarried out in the absence of these substances. Examples of suit-able polymerization regulators are 2-mercaptoethanol, mer-~5 captopropanols, mercaptobutanols, thioglycolic acid, n-dodecylmercaptan, tert-dodecylmercaptan, thiophenol, mer-captopropionic acid, allyl alcohol and acetaldehyde.
The polymerization regulators are used in an amoun~ of from 0.05 to 10, preferably from 0.1 to S, % by weight, based on the amount of monomer used.
From 100 to 1500, preferably from 2ûO to 900, parts by weight of carbon dioxide are used per 1ûO parts by weight of a monomer employed in the homopolymerization or in the copolymerization. The polymerization reaction can be carried out batchwise or continuously in approp~
riately designed pressure apparatuses. In order to remove the heat evoLved during the polymerization, it is desirable - 7 - O.Z. 0050/3~062/38063 for the pressure apparatuses to possess a cod;ng system.
They must of course also be capable of be;ng heated, in order to bring the reaction mixture to the temperature desired for the polymerization in each case. The pres-sure apparatuses must have a mixing means, for examplestirrers (paddle stirrers, impeller stirrers or multi-stage impulse countercurrent stirrers) or blades.
The pressure polymerization can be carried out, for example, as follows: a certain amount of a monomer and the initiator are initially taken in a pressure appa-ratus, after which carbon diox;de in liquid form is intro-duced, the autoclave is closed and the reaction mixture is then heated to the polymerizat;on temperature. How-ever, it is also possible for only some of the reaction mixture to be initially taken in the autoclave and heated to the polymerization temperature, and further reaction mixture to be pumped in at a rate corresponding to the rate of polymerization. In another possible procedure, onLy some of th~ monomer ;n the total amount of carbon dioxide required is initially taken in the autoclave, and the residual amount of monomer together with the initia-tor is pumped in ~o the autoclave at a rate corresponding to the polymerization rate. During the poLymerization, care must be taken to ensure thorough mix;ng of the reac-~ion material. Wl1en the polymerization reaction is com-plete, the reaction mixture is, if required, cooled, and the carbon d;oxide is separated off. In th;s procedure, the homopolymers and copolymers are obtained as a residue in po~der form. The particle size of the powder is from O.S ~m to 0.5 mm, preferably from 1 ~m to 0.5 mm, these particles consisting of primary particles of 0.5-3 ~m di-ameter and forming more or less compact aggregates.
Depending on the conditions chosen for the poly-merization, homopolymers having a Fikentscher K value of from 10 to 300, pref~rably from 20 to 2D0, are obtained.
Apart from a few excep~ions, the homopolymers are water-soluble, the solubility being not less than 1~ 9 of homo - 8 - o.Z~ 0050/38062/38063 homopolymer per liter of water. Of particular importance are the homopolymers of N vinylformamide and N-vinylpyrro-lidone. ~y treating them with a base or an acid, the homo-polymers of N-vinylformamide can be conver~ed to poly-S mers which con~ain not only unchanged copolymerized N-vinylformamide units but also N-vinylamine units. Poly-mers of this type are highly effective flocculants for dewatering sewage sludge and are drainage aids and reten-tion aids in papermaking. Homopolymers which can be pre-pared by the novel process can also be used, for example,as builders in detergents and as textile sizes, adhesive ra~ materials, sizing agents and/or strenghtening agents for paper and in tertiary oil productionc The K values were determined according to H.
Fikentscher, Cellulose-Chemie 13 (193Z), 58-64 and 71-74, in 5~ strength sodium chloride solution at a polymer con- -centration of 0.1% by weight and at a temperature of 25C.
EXAMPLE l 15 9 of N-vinylformamide and 0.3 9 of azobisiso-butyroni~rile are initially taken in a 300 ml autoclave.135 9 of liquid carbon diox;de are added, after ~hich the autoclave is closed and heated to 80C. The autoclave is equipped with a stirrer and an electric heater. The re-ac~ion mixture is stirred during the heating up period and during polymerization, which takes about 5 hours. At a polymerization temperature of 80C, the maximum pressure reached is 160 bar. When the polymerization is compl~te, the con~ents of the autoclave are cooled and the pressure is le~ down. A white flocculent powder having a particle size of from 10 to 300 ~m is obtained. The size of the primary particles is about 1 ~m and the K value of the homopolymer is 30.4.
15 9 of freshly distilled, anhydrous N-vinylpyrro-lidone, 0.3 9 of azobisisobutyronitrile and 135 9 of liq-uid carbon diox;de are initially taken in a 300 ml auto-clave equipped with a stirrer and an electric heater. The - 9 - O.Z. 0050/3806Z/3~063 reaction mixture is stirred and heated to 80C, the maxi-mum pressure relched being 160 bar. After a polymeriza-tion time of 5 hours, the contents of the autoclave are cooled and the pressure is let down. A white polymer pow-der which readily dissolves in water is obtained. Thesize of the primary particle is about 3 ~m and the K value of the homopolymer ;s 57.
15 9 of anhydrous N-vinyl-2-methylimidazoline hyd-rochloride, 0.3 9 of 2,2-azobis-t2,4-d;methylvaleronitrile) and 135 9 of liquid çarbon dioxide are initially taken in 3 300 ml autoclave equipped with a stirrer and an elec-tric heater, water being absent. The autoclave is then closed and heated to 75C, the maximum pressure reached being 155 bar. After a polymerization time of 5 hours, the reaction mixtur0 is cooled and the pressure is let do~n. A ~h;te powder which very readily dissoLves in water is obtained. The size of the primary particles is about 3 ~m and the K value of the polymer is 65.
15 9 of 2-hydroxyethyl acrylate~ 0.3 9 of azobis-isobutyronitrile arld 135 9 of liquid carbon dioxide are initially taken in a 300 ml autoclave equipped ~ith a stirrer and an electric heater~ The autoclave is closed and the reaction mixture is then heated to 80C, the max;-mum pressure reached being 170 bar. After a polymeriza-tion t;me of 4 hours, a ~hite flocculen~ homopolymer ~f hydroxyethyl acrylate which has a K value of 120 and whose primary particles have a diameter of about 2 ~m is obtained.
EXAMPLE S
775 9 of N-vinylformamide, 7.5 9 of freshly dis-tilled N-vinylpyrrolidone and 0.3 9 of tert-butyl perethyl-hexanoate are initially taken in a 300 ml autoclave equip-ped with a stirrer and an electric heater. The autoclave is now closed tightly, nitrogen under 150 bar is forced in, the pressure is let down again and the autoclave is evac-uated to 100 mbar. 135 9 of liquid carbon dioxide is then - 10 - O.Z. 0050/38062/38063 introduced, the autocLave ;s closed tightly and th~ stir-red m;xture is heated to 80C, the pressure reaching 160 bar. After a polymerization time of 5 hours, the con-' tents of the reactor are cooled and the pressure is slowly let down. A white powder which readily dissolves in wateris obtained. The size of the primary particles is about 3 ~m and the K vaLue of the polymer is 53.
7.5 9 of N-vinylformamide, 7~5 g of vinyl acetate, 0.3 9 of azobisisobutyronitrile and 135 9 of liquid carbon dioxide are initially taken in a 300 ml autoclave equipped with a stirrer and an electric heater. The reaction mix-ture ;s stirred and heated to 80C, the maximum pressure reaching 165 bar. After a polymerization time of S hours, the contents of the autoclave are cosled and the pressure is let down. A wh;te powder is obtained. The size of the primary particles is about 1 ~m and the K value of the polymer is 39.
12 9 of N-vinylformamide, 3 g of vinyl ace~ate, 0.3 9 of azobisisobutyronitrile and 135 9 of liquid carbon dioxide are initially taken in a 300 ml autoclave equip-ped with a stirrer and an electric heater. The reaction mixture is stirred and heated to 80C, the maximum pres-sure reaching 165 bar. After a polymerization time of 5 hours, the contents of the autoclave are cooled and the pre~sure is let down. A ~hite powder is obtained. Thb size of the primary part;cles is about 1 ~m and the K
value of the polymer is 37.
The polymerization reaction is initiated with the aid of free radical polymerization initiators. Any ini-S tiators which are conventionally used for polymerizingthe monomers in question may be employed. Examples of suitable free radical initiators are those which have a half life of less than 3 hours at the temperatures selec-- ted. If the polymerization is carried out at two dif-ferent temperatures, initial polymerization o~ the mono-mers first being carried out at a low temperature and poly-merization then being completed at a substantially higher temperature, it ;s a~antageous to use two or more differ-ent initiators which have an adequate rate of decomposi-tion in the particular temperature range selected. Forexample~ the following initiators can be used ;n the tem- ~
perature ranges stated below:
Temperature: 40-60C
Acetylcyclohexanesul~onyl peroxide, diacetyl peroxidi-carbonate, dicyclohexyl peroxidicarbonate, di-Z-ethyl-hexyl peroxidicarbonate, tert-butyl perneodecanoate and 2~2'-azobis-(4-methoxy-2,4-dimethylvaleronitrile).
Temperature: 60-80C
- tert-8utyl perpivalate, dioctanoyl peroxide, dilauroyl peroxide, Z,2'-azobis-~2,4-dimethylvaleronitrile) and tert-butylazo-2-cyanobutane.
Temperature: R0 100C
Dibenzoyl peroxide, tert-butyl per-2-ethylhexanoate, tert-butyl permaleate and 2,2-azobisisobutyronitrile.
Temperature: 100-120C
bis-(tert-8utylperoxi)-cyclohexane, tert-butylperoxiiso-propyl carbonate and tert-butyl peracetate.
Temperature: 120-140C
2,2-bis-(ter~-Butylperoxi)-but3ne, dicumyl peroxide, di-tert-amyl peroxide and di-tert-butyl peroxide.
TempPrature: 140-160C
p-Menthane hydroperoxide, pinane hydroperoxide, cumene ~ 6 - o.Z~ 0050/38062/38063 hydroperoxide and tert-butyl hydroperoxide.
8y using redox coini~iators, for example benzoin, dimethylaniline and complexes and salts of heavy metals, such as copper, cobalt, manganese, iron, nickel and chrom-ium, ~hich are soluble in organic solvents, it is pos-sible to reduce the half l;ves of the stated peroxides, in particular the hydroperoxides~ so that, for example, tert-butyl hydroperoxide in the presence of 5 ppm of cop-per(II) acetylacetonate is effective at as low as 100C.
The polymerization initiators are used in the con-ventional amounts for polymerization; for example, from 0.05 to 10, preferably from 0.1 to 5 parts by weight of an initiator are required per 100 parts by weight of the monomers.
The polymerization can~ if required, also be car-ried out in the presence of polymerization regulators to regulate the molecular weight of the polymers. Where it is desired to prepare copolymers having a particularly lou molecular weight, larger amounts of polymerization regulators are used, whereas only small amounts of these regulators are ~mployed for the preparation of h;gh mole-cular weight copolymers, or the polymerization is çarried out in the absence of these substances. Examples of suit-able polymerization regulators are 2-mercaptoethanol, mer-~5 captopropanols, mercaptobutanols, thioglycolic acid, n-dodecylmercaptan, tert-dodecylmercaptan, thiophenol, mer-captopropionic acid, allyl alcohol and acetaldehyde.
The polymerization regulators are used in an amoun~ of from 0.05 to 10, preferably from 0.1 to S, % by weight, based on the amount of monomer used.
From 100 to 1500, preferably from 2ûO to 900, parts by weight of carbon dioxide are used per 1ûO parts by weight of a monomer employed in the homopolymerization or in the copolymerization. The polymerization reaction can be carried out batchwise or continuously in approp~
riately designed pressure apparatuses. In order to remove the heat evoLved during the polymerization, it is desirable - 7 - O.Z. 0050/3~062/38063 for the pressure apparatuses to possess a cod;ng system.
They must of course also be capable of be;ng heated, in order to bring the reaction mixture to the temperature desired for the polymerization in each case. The pres-sure apparatuses must have a mixing means, for examplestirrers (paddle stirrers, impeller stirrers or multi-stage impulse countercurrent stirrers) or blades.
The pressure polymerization can be carried out, for example, as follows: a certain amount of a monomer and the initiator are initially taken in a pressure appa-ratus, after which carbon diox;de in liquid form is intro-duced, the autoclave is closed and the reaction mixture is then heated to the polymerizat;on temperature. How-ever, it is also possible for only some of the reaction mixture to be initially taken in the autoclave and heated to the polymerization temperature, and further reaction mixture to be pumped in at a rate corresponding to the rate of polymerization. In another possible procedure, onLy some of th~ monomer ;n the total amount of carbon dioxide required is initially taken in the autoclave, and the residual amount of monomer together with the initia-tor is pumped in ~o the autoclave at a rate corresponding to the polymerization rate. During the poLymerization, care must be taken to ensure thorough mix;ng of the reac-~ion material. Wl1en the polymerization reaction is com-plete, the reaction mixture is, if required, cooled, and the carbon d;oxide is separated off. In th;s procedure, the homopolymers and copolymers are obtained as a residue in po~der form. The particle size of the powder is from O.S ~m to 0.5 mm, preferably from 1 ~m to 0.5 mm, these particles consisting of primary particles of 0.5-3 ~m di-ameter and forming more or less compact aggregates.
Depending on the conditions chosen for the poly-merization, homopolymers having a Fikentscher K value of from 10 to 300, pref~rably from 20 to 2D0, are obtained.
Apart from a few excep~ions, the homopolymers are water-soluble, the solubility being not less than 1~ 9 of homo - 8 - o.Z~ 0050/38062/38063 homopolymer per liter of water. Of particular importance are the homopolymers of N vinylformamide and N-vinylpyrro-lidone. ~y treating them with a base or an acid, the homo-polymers of N-vinylformamide can be conver~ed to poly-S mers which con~ain not only unchanged copolymerized N-vinylformamide units but also N-vinylamine units. Poly-mers of this type are highly effective flocculants for dewatering sewage sludge and are drainage aids and reten-tion aids in papermaking. Homopolymers which can be pre-pared by the novel process can also be used, for example,as builders in detergents and as textile sizes, adhesive ra~ materials, sizing agents and/or strenghtening agents for paper and in tertiary oil productionc The K values were determined according to H.
Fikentscher, Cellulose-Chemie 13 (193Z), 58-64 and 71-74, in 5~ strength sodium chloride solution at a polymer con- -centration of 0.1% by weight and at a temperature of 25C.
EXAMPLE l 15 9 of N-vinylformamide and 0.3 9 of azobisiso-butyroni~rile are initially taken in a 300 ml autoclave.135 9 of liquid carbon diox;de are added, after ~hich the autoclave is closed and heated to 80C. The autoclave is equipped with a stirrer and an electric heater. The re-ac~ion mixture is stirred during the heating up period and during polymerization, which takes about 5 hours. At a polymerization temperature of 80C, the maximum pressure reached is 160 bar. When the polymerization is compl~te, the con~ents of the autoclave are cooled and the pressure is le~ down. A white flocculent powder having a particle size of from 10 to 300 ~m is obtained. The size of the primary particles is about 1 ~m and the K value of the homopolymer is 30.4.
15 9 of freshly distilled, anhydrous N-vinylpyrro-lidone, 0.3 9 of azobisisobutyronitrile and 135 9 of liq-uid carbon diox;de are initially taken in a 300 ml auto-clave equipped with a stirrer and an electric heater. The - 9 - O.Z. 0050/3806Z/3~063 reaction mixture is stirred and heated to 80C, the maxi-mum pressure relched being 160 bar. After a polymeriza-tion time of 5 hours, the contents of the autoclave are cooled and the pressure is let down. A white polymer pow-der which readily dissolves in water is obtained. Thesize of the primary particle is about 3 ~m and the K value of the homopolymer ;s 57.
15 9 of anhydrous N-vinyl-2-methylimidazoline hyd-rochloride, 0.3 9 of 2,2-azobis-t2,4-d;methylvaleronitrile) and 135 9 of liquid çarbon dioxide are initially taken in 3 300 ml autoclave equipped with a stirrer and an elec-tric heater, water being absent. The autoclave is then closed and heated to 75C, the maximum pressure reached being 155 bar. After a polymerization time of 5 hours, the reaction mixtur0 is cooled and the pressure is let do~n. A ~h;te powder which very readily dissoLves in water is obtained. The size of the primary particles is about 3 ~m and the K value of the polymer is 65.
15 9 of 2-hydroxyethyl acrylate~ 0.3 9 of azobis-isobutyronitrile arld 135 9 of liquid carbon dioxide are initially taken in a 300 ml autoclave equipped ~ith a stirrer and an electric heater~ The autoclave is closed and the reaction mixture is then heated to 80C, the max;-mum pressure reached being 170 bar. After a polymeriza-tion t;me of 4 hours, a ~hite flocculen~ homopolymer ~f hydroxyethyl acrylate which has a K value of 120 and whose primary particles have a diameter of about 2 ~m is obtained.
EXAMPLE S
775 9 of N-vinylformamide, 7.5 9 of freshly dis-tilled N-vinylpyrrolidone and 0.3 9 of tert-butyl perethyl-hexanoate are initially taken in a 300 ml autoclave equip-ped with a stirrer and an electric heater. The autoclave is now closed tightly, nitrogen under 150 bar is forced in, the pressure is let down again and the autoclave is evac-uated to 100 mbar. 135 9 of liquid carbon dioxide is then - 10 - O.Z. 0050/38062/38063 introduced, the autocLave ;s closed tightly and th~ stir-red m;xture is heated to 80C, the pressure reaching 160 bar. After a polymerization time of 5 hours, the con-' tents of the reactor are cooled and the pressure is slowly let down. A white powder which readily dissolves in wateris obtained. The size of the primary particles is about 3 ~m and the K vaLue of the polymer is 53.
7.5 9 of N-vinylformamide, 7~5 g of vinyl acetate, 0.3 9 of azobisisobutyronitrile and 135 9 of liquid carbon dioxide are initially taken in a 300 ml autoclave equipped with a stirrer and an electric heater. The reaction mix-ture ;s stirred and heated to 80C, the maximum pressure reaching 165 bar. After a polymerization time of S hours, the contents of the autoclave are cosled and the pressure is let down. A wh;te powder is obtained. The size of the primary particles is about 1 ~m and the K value of the polymer is 39.
12 9 of N-vinylformamide, 3 g of vinyl ace~ate, 0.3 9 of azobisisobutyronitrile and 135 9 of liquid carbon dioxide are initially taken in a 300 ml autoclave equip-ped with a stirrer and an electric heater. The reaction mixture is stirred and heated to 80C, the maximum pres-sure reaching 165 bar. After a polymerization time of 5 hours, the contents of the autoclave are cooled and the pre~sure is let down. A ~hite powder is obtained. Thb size of the primary part;cles is about 1 ~m and the K
value of the polymer is 37.
Claims (4)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A process for the preparation of a polymer powder by polymerizing water-soluble monomers selected from the group consisting of N-vinylcarboxamides which are derived from saturated C1-C6-carboxylic acids, di-C1-C3-alkyl-amino-C2-C6-alkyl acrylates, di-C1-C3-alkylamino-C2-C6-methacrylates, hydroxy-C2-C6-alkyl esters of ethyleni-cally unsaturated C3-C5-carboxylic acids, monoesters of acrylic acid with polyalkylene glycols having a mole-cular weight of from 1500 to 10,000, N-vinylpyrrolidone, N-vinylcaprolactam, N-vinylimidazole, N-vinylimidazoline, mixtures of N-vinylformamide and N-vinylpyrrolidone and mixtures of N-vinylformamide and vinyl acetate, in super-critical carbon dioxide with thorough mixing at about 31-150°C and under a pressure above 73 bar, from 100 to 1500 parts by weight of carbon dioxide being used per 100 parts by weight of monomers.
2. A process as claimed in claim 1, wherein from 200 to 900 parts by weight of carbon dioxide are used per 100 parts by weight of the monomers.
3. A process as claimed in claim 1, wherein N-vinyl-formamide, N-vinyl-N-methylformamide, N-vinylpyrrolidone, hydroxyethyl acrylate, hydroxyethyl methacrylate, dimethyl-aminoethyl methacrylate, dimethylaminoethyl acrylate or diethylaminoethyl acrylate is homopolymerized.
4. A process as claimed in claim 1, wherein N-vinyl-formamide and N-vinylpyrrolidone or N-vinylformamide and vinyl acetate are copolymerized.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19853537455 DE3537455A1 (en) | 1985-10-22 | 1985-10-22 | Process for the preparation of pulverulent homopolymers |
| DE19853537457 DE3537457A1 (en) | 1985-10-22 | 1985-10-22 | Process for the preparation of pulverulent copolymers |
| DEP3537457.8 | 1985-10-22 | ||
| DEP3537455.1 | 1985-10-22 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1262995A true CA1262995A (en) | 1989-11-14 |
Family
ID=25837150
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000520638A Expired CA1262995A (en) | 1985-10-22 | 1986-10-16 | Preparation of polymer powders |
Country Status (3)
| Country | Link |
|---|---|
| EP (1) | EP0220603B1 (en) |
| CA (1) | CA1262995A (en) |
| DE (1) | DE3665594D1 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5328972A (en) * | 1992-09-28 | 1994-07-12 | Rohm And Haas Company | Process for preparing low molecular weight polymers |
| US6482917B1 (en) * | 1998-07-24 | 2002-11-19 | Basf Aktiengesellschaft | Method for producing powder-shaped cross-linked polymerizates |
| CN105886131A (en) * | 2016-04-18 | 2016-08-24 | 广东湛丰精细化工有限公司 | Cotton reactive dye cleaning agent and preparation method thereof |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3609829A1 (en) * | 1986-03-22 | 1987-09-24 | Basf Ag | METHOD FOR PRODUCING POWDERED CROSSLINKED COPOLYMERISATS |
| AU2021288A (en) * | 1987-07-30 | 1989-02-09 | B.F. Goodrich Company, The | Solvent free acrylic acid type thickening agents and a method of making same |
| DE3909004A1 (en) * | 1989-03-18 | 1990-09-27 | Basf Ag | USE OF NON-HYDROLYSED N-VINYLFORMAMIDE UNITS CONTAINING COPOLYMERS IN PAPER PRODUCTION |
| DE3909005A1 (en) * | 1989-03-18 | 1990-09-20 | Basf Ag | USE OF NON-HYDROLYZED N-VINYLFORMAMIDE UNITS CONTAINING COPOLYMERISES AS FLAKING AND TEMPERATURES |
| DE19618833A1 (en) * | 1996-05-10 | 1997-11-13 | Bayer Ag | Process for the production of ethylene-vinyl acetate copolymers |
| DE10054114A1 (en) * | 2000-10-31 | 2002-05-16 | Dupont Performance Coatings | Process for the preparation of powder coating compositions |
| DE102005053559A1 (en) | 2005-11-08 | 2007-05-10 | Basf Ag | Process for the preparation of polymer powders containing vinylformamide units |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3522228A (en) * | 1966-05-19 | 1970-07-28 | Sumitomo Chemical Co | Novel method for polymerizing a vinyl compound in the presence of a carbon dioxide medium |
-
1986
- 1986-10-15 DE DE8686114235T patent/DE3665594D1/en not_active Expired
- 1986-10-15 EP EP86114235A patent/EP0220603B1/en not_active Expired
- 1986-10-16 CA CA000520638A patent/CA1262995A/en not_active Expired
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5328972A (en) * | 1992-09-28 | 1994-07-12 | Rohm And Haas Company | Process for preparing low molecular weight polymers |
| US6482917B1 (en) * | 1998-07-24 | 2002-11-19 | Basf Aktiengesellschaft | Method for producing powder-shaped cross-linked polymerizates |
| CN105886131A (en) * | 2016-04-18 | 2016-08-24 | 广东湛丰精细化工有限公司 | Cotton reactive dye cleaning agent and preparation method thereof |
| CN105886131B (en) * | 2016-04-18 | 2018-08-31 | 广东湛丰精细化工有限公司 | A kind of cotton reactive dye cleaning agent and preparation method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| DE3665594D1 (en) | 1989-10-19 |
| EP0220603B1 (en) | 1989-09-13 |
| EP0220603A1 (en) | 1987-05-06 |
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