SE449362B - ACRYLAMIDE AND ACRYLIC ACID POLYMERS CONTAINING A CYCLIC ORGANIC COMPOUND WITH A 1,3-DION GROUP AND THE COMPOSITION AND PROCEDURES FOR THEIR PREPARATION - Google Patents

Description

449 362 to a high molecular weight water soluble product. However, these monomer solutions or powders obviously contain unknown impurities in parts per million, the exact amount or type not being determined to date.

When the monomers are polymerized, even with this very low content of impurities, quite often completely unacceptable polymers are obtained as a result.

In the solution polymerization, attempts to solve these problems required some or all of: (a) very low drying temperatures; (b) extensive and expensive purification of the monomer solution; (c) very long polymerization times; (d) adding very large amounts of urea to the monomer; and / or (e) polymerization in highly dilute solutions. However, each of these has proved unsatisfactory for large-scale commercial use either because they are energy-intensive or expensive by drastically reducing the rate of polymer production or by reducing the percentage of polymer desired to an unacceptable level.

In water-in-oil emulsion polymerizations, attempts to solve these problems involved: (a) monomer purification; (b) polymerization of highly dilute solutions; (c) use of various initiators; (d) adding urea to the monomer and (e) using chain transfer agents. However, these have also been found to be unsatisfactory for the same and similar reasons as stated above. "Accordingly, an object of the present invention is to overcome this problem to allow polymerization of a concentrated monomer solution to occur without extensive purification, i.e. crystallization, required.

A further object is to reduce the content of insoluble substances in dry, solution polymerized polyacrylamide and polyacrylic acid polymers to a commercially acceptable level, i.e. under about 2% by weight.

Yet another object is to increase the standard viscosity of emulsion polymerized polyacrylamide and polyacrylic acid polymers to an acceptable level, i.e. over about 4.5 centipois resp. 5.0 centipoise.

Yet another object is to reduce the amount of crosslinked polymer formed during polymerization and / or during drying or milling of an acrylamide or acrylic acid or 2-acrylamido-2-methylpropanesulfonic acid polymer.

Yet another object is to increase the polymerization rate of monomers of acrylic acid and 2-acrylamido-2-methyl-propanesulfonic acid type.

According to the present invention there is provided an acrylamide and / or acrylic acid and / or 2-acrylamido-2-methylpropanesulfonic acid monomer solution having therein a cyclic organic compound containing a moiety of the formula i. The cyclic compound (hereinafter referred to as a 1,3-dione) is preferably present in an amount sufficient so that after polymerization of the monomer an improved product, preferably a commercially acceptable product, is obtained. as a result and / or the polymerization rate increases. For solution polymerizations, this usually means a content of insoluble substances of less than about 2% by weight. For acrylamide or acrylic acid homopolymer emulsion polymerizations, this means a content of insoluble substances that is low enough not to intentionally reduce the standard viscosity below about 4.5 centipoise. If a lower viscosity emulsion polymerization product is intentionally desired, the 1,3-dione can be used to increase the reaction rate. For homopolymers of acrylic acid or 2-acrylamido-2-methylpropanesulfonic acid and its salts, this means increasing the polymerization rate.

Furthermore, there is provided a process for preparing a high molecular weight water-soluble polyacrylamide or polyacrylic acid polymer in which the insoluble matter content is reduced to below about 2%, which comprises polymerizing acrylamide or acrylic acid monomer in an aqueous solution, optionally with other ethylenically unsaturated monomers. and drying the resulting polymer, wherein at least the drying is performed in the presence of a 1,3-dione.

In addition, there is provided a process for preparing a high molecular weight water-soluble polymer comprising emulsion polymerization of an acrylamide or acrylic acid or 2-acrylamido-2-methylpropanesulfonic acid monomer, optionally with other ethylenically unsaturated monomers in the presence of a 1,3-dione.

Furthermore, a process for increasing the polymerization rate of homopolymers of 2-acrylamido-2-methylpropanesulfonic acid and its salts is provided, the polymerization being carried out in the presence of a 1,3-dione.

These and other purposes will become apparent from the following detailed description.

The compounds used here for the preparation of improved polymers are the cyclic organic compounds which contain a moiety of the formula: O ui -c-CH 2 - These compounds are designated 1,3-diones although the moiety may be present in other places in the association. 449 362 Examples of such 1,3-diones include, but are not limited to, both substituted and unsubstituted derivatives of 1,3-cyclopentanedione; 1,3-cyclohexanedione; 1,3-cycloheptanedione; 1,3-cyclooctanedione; 1,3-cyclodecandion; 5,5-dimethyl-1,3-cyclohexanedione; 5,5-diethyl-1,3-cyclohexanedione; 1,3,5-cyclohexanthrione and its tautomeric phloroglucinol (1,3,5-trihydroxybenzene); tetrahydronaphthalene-1,3-dione; barbituric acid and other such compounds.

The tautomers of these compounds having the group -E-CH = $ -, OH are included within the meaning of 1,3-dione as used in the present invention in the same manner as the metal olates including carbalkoxide dimedon metal olates such as carboxymethoxydimedonium sodium nolate, carbethoxydimedon potassium enolate and the like. The 1,3-dione is preferably 5,5-dimethyl-1,3-cyclohexanedione, also known as methone or dimedone.

When the 1,3-dione is added to the monomer and the monomer is subsequently polymerized, the 1,3-dione must not also be a polymerization inhibitor. If it is an inhibitor, it must be separated from the monomer before polymerization. One way of such removal is by passing the monomer solution through a bed of activated carbon. Alternatively, for a solution polymerization, the 1,3-dione may be added to the polymer gel prior to drying.

If the 1,3-dione is not stable under the polymerization conditions, then the polymerization conditions must be modified to avoid; destabilization or the 1,3-dione must be added to the polymer gel before drying. ššš In some cases as described in detail below, it has been found desirable with the 1,3-dione to comprise up to about 20% by weight (based on the monomer content) of urea or a 449,362 urea derivative. Preferably 5-10% of urea is used. Suitable such compounds are described in U.S. Pat. No. 3,622,533, which is hereby incorporated by reference. The urea can be added before, after or at the same time as the 1,3-dione.

The monomers to be polymerized here are acrylamide, acrylic acid and 2-acrylamido-2-methylpropanesulfonic acid and its salts. Copolymers of these listed monomers or one or more of the listed monomers with other ethylenically unsaturated monomers suitable for the preparation of water-soluble products may also be prepared. Such other monomers include, but are not limited to, methacrylamide, salts of acrylic acid, methacrylic acid and its salts, methyl acrylate, ethyl acrylate, propyl acrylate, methyl methacrylate, ethyl methacrylate, dimethylaminoethyl acrylate, dimethylaminoethylacrylamethylacetylamethylacetylamethylacrylate, hydroxyethyl methacrylate, diethylaminoethyl acrylate methyl sulfate, styrene, acrylonitrile, 3- (methyl acrylamido) propyl-trimethylammonium chloride, vinyl methyl ether, vinyl ethyl ether, alkali metal or ammonium salts of vinyl sulfonic acid and the like.

All or part of the acrylic agent of the polymers may be hydrolyzed.

The polymerization method to be used is any that is conventionally used for the polymerization of such monomers. This especially includes solution and emulsion polymerizations, although other methods, such as bead and suspension dispersion polymerizations, may be used. The particular polymerization system for each of these is that conventionally used. For solution polymerization, this usually involves the use of one or more azo initiators, with or without a redox system, and possibly such conventional additives as sequestrants, alcohols and diluents necessary for the polymerization. For emulsion polymerization, which is a water-in-oil emulsion, this involves the use of a water-in-oil emulsifier, an oil phase such as toluene, xylene, or a paraffin oil, and a free radical initiator.

Since the present invention is independent of the particular polymerization method, further details on this can be readily found in the literature. In addition, the amounts and the individual components will vary in accordance with the monomers being polymerized and the process conditions under which the polymerization is to take place.

The amount of 1,3-dione to be used in accordance with the present invention has been found to depend at least in part on the type of polymerization, the type of monomer purification, the degree of aging of the monomer / 1,3-dione composition, for solution polymerizations the temperature at which the product is prepared and / or dried, the presence or absence of urea and the amount thereof, the amount of impurities in the concentrated monomer solution, and the residence time of the polymer at the maximum temperature. An exact "polymer-enhancing amount" cannot be defined as such. However, it will usually range from about 0.001% to 2% by weight (although more may be used) based on the monomer, and in particular with emulsion polymerizations using the larger amounts and solution polymerizations with lower amounts. For emulsion polymerizations, the preferred amount for non-aged or room temperature aged solutions is about 0.3-1% and the most preferred is about 0.4-0.7% by weight. When accelerated aging (above about 50 ° C for more than about 2 hours fl is used, the preferred amount is from about 0.005 to 0.2% and the most preferred 0.007 to 0.1%. For solution polymerizations, the preferred amount is about 0.03 to 0.4% and the most preferred is approximately 0.05 to 0.25% by weight.

For solution polymerizations of acrylamide and acrylic acid, it has been found advantageous to (a) purify the concentrated monomer solution by contacting it with a 449,362 cation exchange resin and / or activated carbon - it is not known what is removed by these steps but improved results - tat has been observed; (b) further use of the urea when the drying temperature is above about 80 ° C, in particular above 85 ° C, and especially especially 90 ° C or above and (c) use of the monomer / 1,3-dione solution as soon as possible, i.e. . without significant aging. In addition, the benefits of the present invention can also be achieved by adding the 1,3-dione, not to the monomer, but instead to the resulting polymer gel before drying thereof.

This is not as desirable in that there may be great difficulty in uniformly mixing the 1,3-dione into the gel.

This shows that, after all, the 1,3-dione acts and seems to act during the drying step in a solvent polymerization.

For emulsion polymerizations, it has been found advantageous to (a) age the monomer / 1,3-dione composition for about 5 days before use, or (b) age the composition at elevated temperature for a few hours (60-BOOC for about 5 hours) before use. This aging has been shown to increase the effect of 1,3-dione. However, beneficial effects have been achieved without aging through the use of larger amounts of the 1,3-dione, i.e. about 0.9-2% based on monomer.

For the preparation of the acrylamide or acrylic acid / 1,3-dione solutions of the present invention, it has been found advantageous to dissolve the 1,3-dione in the concentrated solution of monomer before each dilution for polymerization purposes. This is due to the extended time that has been shown to be necessary for dissolving the 1,3-dione in a dilute solution, although no significant difference in performance has been observed.

To prepare the 2-acrylamido-2-methylpropanesulfonic acid / 1,3-dione solutions, the two can simply be mixed with water.

Alternatively, the 1,3-dione can be incorporated into the acrylonitrile or the propylene from which the monomers are prepared.

The invention is further illustrated by the following examples in which all parts and percentages are by weight unless otherwise indicated.

Example 1 Preparation of acrylamide / 1,3-dione solutions (a) To a polyethylene coated vessel, preferably one in which the subsequent polymerization will take place if it is the solvent polymerization, was added 810.9 grams of 51.3% aqueous acrylamide. as such "and 0.83 grams of methone.

This mass was magnetically stirred in air for about 5 minutes to effect dissolution of the methone. It contained 0.2% methone based on acrylamide monomer. (b) The procedure of (a) was repeated except that before the addition of the methone, the aqueous acrylamide was passed through a bed of cation exchange resin (Amberlite (R) IR-120 from Rohm and Haas). (c) The procedure of (a) was repeated except that before the addition of the methone, the aqueous acrylamide (i) was passed through a bed of cation exchange resin (Amberlite (R) IR-120) and (ii) was then passed through a bed of activated carbon. (Nuchar WV-L 8 x 30 mesh). (d) Other such solutions were prepared with varying amounts of methone as shown in the following examples.

Example 2 Solution polymerization of monomer in Example 1 (c) The monomer solution in Example 1 (c) was solution polymerized as follows: The solution was placed in a 3.75 liter polyethylene reactor and magnetically stirred. The following materials were added 449 562 then with continued stirring: 23l, 2 g deionized water 4.2 ml 2% aqueous ethylenediaminetetraacetic acid 3.2 ml 10% aqueous isopropanol 16.6 g anhydrous sodium sulphate 4.2 g anhydrous ammonium sulphate 20.8 g urea When the solution was complete, the pH of the reaction mass was adjusted to 3.0 with sulfuric acid. A nitrogen purge was initiated at about 1000 ml per hour for 30 minutes while heating the reaction mass to about 35 ° C. With continued nitrogen blowing, the polymerization started within a few minutes after the introduction of the catalysts: 13.31d of OJD78gram / ml of 2,2'-azobis (2,4-dimethyl--4-methoxivaleronitrile) and 15.6 ml of 0.02 grams / ml of 2,2'-azobis (cyanovaleric acid) The polymerization was allowed to proceed substantially adiabatically by isolating the reactor. The polymer was subjected to a 29.8 ° C exotherm for about a two hour period before being transferred to a curing oven at about 70 DEG C. where it was cured for a further 18 hours to give 3,200 grams of a rigid gel product.

The gel was then cut into strips and portions of it were dried in a conventional oven to 7-10% residual volatiles at temperatures of 90, 100 and 133 2 ° C. The dried product was reduced in particle size in a Waring mixer and sieved to give a product having a -20 U.S. Pat. mesh particle size.

Example 3 Evaluation of the product of Example 2 To evaluate the product prepared in Example 2 449 3620 ll, the following procedure was used: 0.3 grams of the product dried at each temperature was dissolved in deionized water to produce 300 grams of a 0.1 percent aqueous polymer solution. The solution was passed through a 100 U. S. mesh weighted sieve to filter out insoluble substances. The screen was dried with approximately 500 ml of deionized water at room temperature and dried at 100 ° C overnight before determining the amount of insoluble matter, which is expressed as the percentage of insoluble matter.

The percentage of volatiles remaining was determined by measuring the weight loss of a 1 gram sample after drying at 100-110 ° C for two hours.

The degree of hydrolysis (% carboxyl) was determined by a conductometric titration of the carboxyl content of the polymer. The lower the value reported, the better the resulting product for nonionic substances.

The viscosity "as such" was determined by dissolving 0.3 grams of product in deionized water for two hours to obtain a 300 gram aqueous solution, filtering out the insolubles through a 100 US mesh screen and then adding sufficient sodium chloride to prepare of a one-molar NaCl solution and determination of the Brookfield viscosity therefore using a UL adapter, which is indicative of the performance of the resulting product, the higher the value, the more suitable the product.

The results, together with a comparative sample prepared by the same procedure but no methon was used, are reported in the following Table I. The results clearly show that by adding 0.2% methon to the monomer the viscosity is increased "as such" and the percentage of insoluble substances from about 60% to less than 0.4%. _ 449 362 12 1 | m ~ .om ~ °. ° «.Nw o. ° w °« .ø ~ ° .o oH.m ~> .ß @ m.ß ~ o.> «.H« .H ~ .m mm mwmmw uoom wwmwmmm: mwmmm m> oo Hæxonnmx w mo.o Hmmcmuwn f w mm flfl mm fl o w Nß.ß Hwmcmumnøm mm al uxæ fl m w mm =% mUWm E0m =. # 0u al momm fl> mwmmn _ .mEwumwc al cxHoH ..> onmmmH0umwEmW .mñmß mmm fifl xnon _N Hmmñwxü> oHmwmHwHmMEw fi zoo N awmämxw al UMV al ømwm Example 4 The procedure of Examples 2 and 3 was repeated except that the amount of methone was reduced to 0.10 and 0.10, respectively. 0.05%.

The following results were obtained: Drying temperature OC 0.10% methone 20 LQQ Viscosity "as such" 3.3 3.3% volatiles 8.25 7.08% insoluble substances 0.9 0.7% carboxyl - 0.15 0 .05% methone viscosity "as such" 3.3 3.1% volatiles 8.21 6.67% insoluble substances 1.6 13.1% carboxyl 0.15 0.075 The results show that when the amount of methone is reduced the percentage of insoluble substances increases whereas when the amount was 0.05% and when the drying temperature was 100 ° C there was an insufficient amount of methone to bring the insoluble matter content below 2%.

Example Gel 5-10 The procedure of Examples 2 and 3 was repeated except that (1) the purification procedure and (2) the amount of methone were varied.

The results are reported in Table II. As can be seen, when the amount of methon was increased, an improved product was obtained as a result (as evidenced by increased viscosity within "as such" and reduced amount of insoluble substances). 449362 II .nopws> m mumm fififl u wuww »MH fiflfl u wwmmwpø uwaocoa et al ox p> fl @ microns .wuumsnmumn f o f umm mc al oo f m> cm WUWM nßumuwmñwuwë fl u @ f> Gmmw MLM NMU flfi m .wunmsnmvænno al UMX vmmønm QH Hwmëmxm al Eomwm muumanmuænco fi UMX vmmø al m o \ o mm. @ \ ~ .fl H ~ .m \ ~ .H ~ .m \ mm wmo. \ m> o. ~ @ .m \> ~ .w m.H \ m fi »o H.m \ m.m m> Q. \ mH. .>. w \ «~.>> .o \ m.o m.m \ m.m m> o. \ | mm.w \ mw.> æ.o \>. H m.m \ m.m 1 \ | ~ w.m \> m.ß H.m ~ \ fi. m fl fi. ~ \ «. ~ | \ 1 @Hm \ om.w H.mm \ m.mm mH \ mH mwmmmm @% 1 »w fl wmw fl w |||| mw fi HWwHm; || mmwww-som WN w» wp fl woxm fl> mm fl axuop o ° oH \ o @ m uH> pxøwoum »nov Hmm wpmn wN.o mw.o mN.o oN.o mo.o .QOUGE PCHQOOHN o fl I m Hwmâwxw fl umu fl dmwm HH AAMNGB fififlfl v A fifi v A fl v fiflfi o fi w fi m fl w m m m m. Examples 11-11 The basic procedure of Examples 2 and 3 was repeated except that the treatment of the monomer, the presence and amount of urea and methone, the catalyst system and pH, the percentage of solids, the maximum temperature and the time at the maximum temperature were varied as described in detail. in the following Table IIa. Regarding the treatment of monomer, "YES" means that it was cation exchange treated as in Example 1b and "NO" means that it was prepared as in Example 1a.

The percentage (NH 4) 2 SO 4 in Example 2 was 1%; the percentage of Na2SO4 was 4% and the percentage of urea was 5%.

Data for dry product are reported in Table IIb.

To show that the 1,3-dione and / or urea can be omitted from the monomer and added to the gel, whereby they are present only during the drying step, various after additions were carried out as follows: Example 15 - 0.1% methone and 10% urea added after Example 16 - only 0.1% methone post-added Examples 19 and 20 ~ only 10% urea post-added Data for dry product for these are also reported in Table IIIb.

As can be seen from the values in Tables IIIa and IIIb, the effect of methone is independent of the catalyst system or polymerization conditions and an advantage is obtained by using a combination of methone and urea. _ 449 362 m_w mm .w fi uo fi xouwænAnømonmoc fl w fl šmlmvm fl QoNm | .m.N un m 16 ou mw m. ~ «Om mw n. Flfl ON fi w. ~ .- om nu __m. ~ Fi cm mm m.A ~ am mm m. Fifi ON E. 2. ow aß na om on n. "om oh nu U fl% fl %%% .xwm.a.wQ fl w mummm øm fi nma: WHM pumm fiflfl ß: fl w fl uwm fl m wH_o« mm Hmmëmxm Eom mäšmm vw <| mm \ H0umm> fl mumM NIII HO: GN. .. .. | H5 _. 3 m 1 °. ~ °. = H ~. ° mn md m 1 0. " =. ° ~ H. ° .hd m .. ... n 0.3 | ._ 3 m ... Sn ... m | .. wwz 2 4 I o- fl OÅZ .. mø-O: vd 4 ° .v = .H ° .m m °. = = n fl 4 Qi .. QÅ ... m Wo _. 2 4. om OH CI Nc MW HM .m> Hm% fi¶ m wmmšmxm mHHH q fl mmm fi mc flfl wømswm 449 362 17 | \ H.ß | \ ° »~« \>. m | \> m. ° fl ~. m \ ~ =. @ ~. «\ ~.« Mv.w \ Nw.m m.æ \ mH.o | \>. M | \ @. M ~ .fl \ @. ~ «.Fi \ ~. ~ | \ @« @ «\ H.ø« | \ «.« | \ Mm «> .w \ ~ .æ mm \ æ. @ M. @ \ ° .m ° .HH \«. H ~ .m \ m. ° H ~. «~ \ M.HH @. @ \ @. ~ H w. ~ @ \>. @ W wæ.> \ M @. @ M.« \ W. ° mm.> \ ~ @. @ Mm ~ \>. mm mm. @ \ mw.> @ .o \>. H m @.> \ -. @ ~. @ «\ m.om | \«. ~ | \ æ. ~ «. ~ \ wm ~ . ~ \ mm H. ~ \ ø.m ~. ~ \ ~ .H ~ .m \ «. m ~. ~ \>. H m. ~ \ ~. ~ mH \ mH w uw fl # NmHm_ #mAHwoHo w: mmmm Eom vm al uxæ fl m - @ wu al moxm fl> um fi ww H flfl v uwwvmm fififi uuwwwm w umHHw0H0 w cmmmm Eom H0uHmOMmH> .HOWPNWHHHDHÜQMÜ .NMUWQ NaOH QHHH AÅMNGH Mo al nxnou oooQH \ oom wH> wxøwoum Hua »www wwmn about ma ma SSA, ma ma v fi now Na AH f mmâwxm 449 362 18 Examples 21-28 The basic procedure of Examples 2 and 3 was repeated except that the following were used: various untreated monomer, 27% solids, diethylenetriaminepentaacetic acid as sequestering agent, 2,2'-azobis (2-amidinopropane) hydrochloride as catalyst with an ammonium persulfate / ferroammonium sulfate redox system, pH 6.0, initiation of reaction at 0 ° C and a residence time of four hours.

The amount of methon and urea used as well as data for dry product for product dried at about 60-70 ° C to about 12% volatile material are shown in the following Table IV.

As can be seen, under these polymerization conditions, methone alone gave acceptable product (high viscosity as such and insoluble content below about 2%) while urea alone did not. 449 362 19>. @ Fl. «° .m H.w m.« M. ~ 0. » fl. m o.H ~ .m @ .m 1 @ .o w. «| m.H w. «1 w. ~«. «| .. ~ .ß m.m | Hm fl nwumñ Gmwmw Eom pm fifi mm fl o w - »w» fi moxm fi> mmmmww. vxøwoum Huou mmm mumn wml fl m cm fl mšwxw bn umvadmmm> H nqmmwa Ho mo.o Ho.ø GOHÜGH 0 mm ßm mN mm vw mm NN HN Hwm fi wxm 449 362 with stirring for about 5 minutes. The following procedure was used except that when the pH was 9, sodium hydroxide was added.

To a suitable reaction vessel are added 200.0 parts of acrylamide, as a 50.47% aqueous solution, and 850.0 parts of deionized water. To this solution is added 2.12 parts of the disodium salt of ethylenediaminetetraacetic acid and 1.5 parts of hydrated ferric sulphate (72% Fe 2 (SO 4) 3) used as 4.5 parts / 1000 parts of H 2 O). The pH of the resulting solution is set to 5.0. This constitutes the water monomer phase.

The oil phase is prepared by dissolving 90.0 parts of sorbitan monooleate in 1040.0 parts of AMSCO OMS, a commercially available, clear oily liquid marketed by Union Oil Co. of California.

The complete oil phase system is added to a suitable high speed homogenizer. The homogenizer is started and the water monomer phase is slowly added to form an emulsion having a viscosity of 990 cP. The dispersed phase of the resulting emulsion has a particle size of about 2.5 microns or less.

To a suitable reaction vessel is added the complete emulsion system with stirring. 70.0 parts per million (based on monomer) of t-butyl hydroperoxide are added. The resulting medium is purged with nitrogen to remove oxygen from the system. Stirring is continued and sodium metabisulfite is slowly pumped into the vessel over a period of 6 hours while the vessel is poured at about 40 ° C after which about 100 parts per million (based on monomer) have been added.

The resulting viscous emulsion shows 99.49% conversion of acrylamide. Stabilization of the polymer emulsion is performed by adding 78.28 parts of a 30% aqueous sodium metabisulfite solution.

The emulsion is kept under plymerization conditions (60 minutes at 40 ° C) for substantially complete reaction of the remaining acrylamide. 0.4% of the emulsion comprises bisulfite which stabilizes the polymer system.

To the resulting polymer emulsion is added, as a conversion agent mixture over a period of 30 minutes, 1.5% of a 70% solution of sodium bis (2-ethylhexyl) sulfosuccinate in AMSCO OMS and 2.0% of the reaction product of 1 mole of octylphenol and 7.5 moles of ethylene oxide. The resulting emulsion is kept at 40 ° C for another 1 hour after which the product is smooth and particle free. The dispersed polymer phase has a particle size of 2.5 microns or less. The standard viscosity is shown in Table V.

The standard viscosity of the resulting product as well as those of other products in which the amount of methon and the degree of aging are varied are reported in the following Table V. _ 449 362 22 Nv mm mm uwu mm mmmmmwmmmmmmmmmw cø fl wmm fi nmñæaømm fl o fl m fi dñw> fl> c0 # wE umGu> @m | ow .ma fl nø fi m ømuwuw fl wuum älm mm ualn mmmmm cmNW.mG fi HuH @ wmnwm Ammümxm H umu flfl mwm> Å fl mm fifi Ao mo No mo No m. fl o. fl mb.o mo couwå W 0 ¥ æm mwm Hmmm mm Hwm fi wxm 449 362 23 Example gel 39-42 Preparation of copolymers The basic procedure of Example 2 is repeated except that 10% by weight of the acrylamide is replaced by an equivalent amount by weight of each of the following monomers: (a) acrylic acid (b) 2 ~ acrylamido-2-methylpropanammonium sulfonate (c) dimethylaminoethyl methacrylate methyl sulfate.

For (a) and (b), the pH is adjusted with sodium hydroxide.

Comparable improved results compared to those for the same copolymer without methone are observed.

Example gel 43 Preparation of 95/5-acrylic acid / acrylamide copolymer To a stainless steel beaker was added 214 grams of isacrylic acid (Rohm and Haas production quality). While stirring with a magnetic stirrer, 29% aqueous ammonia was added (technically) and the temperature was maintained at <§35 ° C until the pH became 7.5 (about 1.5 hours). Distilled water was added. to bring the total weight to 428 grams. The solution was transferred to one liter glass beaker and 1.07 grams of methone (0.5% based on the acrylic acid) was added with stirring. It dissolved in about 10 minutes. Then, 23 grams of 50% acrylamide was added and the procedure of Examples 29-38 was repeated for emulsion polymerization of the monomers.

The standard viscosity was 5.7 centipois.

When the above procedure was repeated without methone, the standard viscosity was less than 2.9 centipois.

Example 44 Preparation of acrylic acid homopolymer The procedure of Example 43 was repeated for homopolymerization 449,362 24i of acrylic acid. It had a standard viscosity of 5.2 cP. When no methone was added, the standard viscosity was 2.5 cP.

Example Gel 45-50 The procedure of Example 2 was repeated except that the methone was replaced with the additives listed in the following Table VI in the amounts specified therein. The results of drying of the polyacrylamide at 90 ° C are also reported in the table. As can be seen, carbethoxydimedon sodium enolate, which may be an intermediate in the production of methone, provided the best results of the additives tested. 449 362 mo.ø ßo.ø am a.vH> .mN mm _m.ßm 25 mm mm cm «.N mm mH nmømm Eow ßwH.o mN.o .ßwH.o v fi. O ßH.o NH.o» m fi nmm fi o w ww fi ßxw fi w W v @ uHmOMmH> Uoom flfi>. Cxu0u W fl> uxd fl onm uwou Mmm mama m fl mwa fifl ß w H> Å flfl mš fi o 0 m = o ||| m ALJli¶ // \\ mo + mz u mmNUO \\\\ _um fi0 QmEd fl unøø mv Go fl wñ flflfi xøuwnnmm mv ønhmn fl u fi numm ßv Høn fl oø fl mouo fi m mv c0 fl w fi mNmQ0Hx> u | m_ fl mw umm 2 Hwum 44 Hwum The weight of the monomer did not polymerize because the 1,3-indandione was an inhibitor of the polymerization.

The procedure of Example 15 was repeated to perform a post-addition of 1,3-indandione (0.2%) and urea (5.0%). The polymer, prepared without any additives, was thus dried in the presence of the additives. The results of a drying at 90 ° C were as follows = Viscosity as such 2.9% volatiles 7.4% insolubles 0.13 The solubility content was thus below about 2%.

Example Gel 52 Meldrum Acid The procedure of Example 2 was repeated except that the pH was varied and the methone was replaced with 1.03% Meldrum Acid: Two polymerizations were performed, one at pH 4.5 and one at pH 8.0. As can be seen from the following data, an improved product was obtained at the higher pH. Accordingly, it is apparent that the 1,3-dione, if present during polymerization and not merely as a post-additive, must be stable under the polymerization conditions to be effective.

The result for products dried at 90 ° C was as follows: EH 4.5 EH 8.0 viscosity as such 1.4 2.1% volatiles 9.9 9.2% insoluble substances 60.0 38.5 Examples 53-64 Using the basic procedure of Example 2, the copolymers and homopolymers listed in Table VII were prepared. Comparative samples without methon were also prepared.

In the table, AMD is acrylamide; AMPS 2-acrylamido-2-methylpropanesulfonic acid; AN is acrylonitrile; and MAPTAC is 3- (methylacrylamido) propyltrimethylammonium chloride. WNF means that the product could not be filtered and thus a determination of the percentage of insoluble material could not be made.

Examples 57 and 58 contained 5% urea and were performed at 10.3% solids. Examples 59-62 were carried out in the absence of urea and at 13% solids. Examples 63 and 64 were performed in the absence of urea and a redox system but with sodium hydroxide to adjust the pH.

For the 100% AMPS examples, 63 and 64, the average polymerization rates expressed as exothermic degrees Celsius / minute were determined adiabatically to the following: Example Meton 'Speed 63 No 0.07% / min. 64 Yes 0.14% / min.

The use of methon thus doubled the polymerization rate.

Examples 53-62 show the effect of using methone to reduce the amount of insoluble substances. 449 362 28 .E _.

° H.o \ | @ .m \ | «.H \ | H.o m @ .o \ | m.m \ | m.H \ | 1111 q @ m = H \ qwmøH mm \ wm m. ~ \ @. ~ Ho HQ NQ \ cw @ aH H; w \ ~ .m .mm \ mm Ho @zz \ mzz wm \ «. M Qm \ ø. m | »|| = m @ cH \ = mm = H @ .m \ m.m o.m \ @. m H.o H .- \>. @ «.m \ m.m @ .m \ ~. ~ |||| | \ ~ H. @ | \ Hm | \ ß. ~ MH. ° | \>.> | \>.> «\ MN 1111 @. ~ H \ m.> M.> \ M.æ m. ~ \ «.« HQ m. ~ @ \ M.mm Hw \ mw ~ .H \ mH ||| «.HQWEMUWQÜW .HUmCMPWDDM ww flfl mw fl o w mm fl pxæ fl m W nmømw eow.Mw fl> mouwa. MCOOOHQUMH> uxøwoum uno »www mama uoooH \ ooQ @« m | mm umamëmxm fl umv fl dmw fi HH> Aqmmma: _ mmzm AND mm: <oø fi oz <| om .mmz <| oH Qz «| om .mmz <-oH nsmumm. : <| m nz «| mm .wmz <| m nsmnmm .mm: <| m nzmfmm _wmz <| mn: <| om_oæam <: | o ~ az <| Qm.u« am <2 | o ~ o: < | mm_z <| H nz «« mm_z <| ~ w fl OE> m Hwšo fl oä vw mm Nm Hc if mm mm ßm wm mm wm mm «WmEwxm 449 362 29 'Example gel 65 The procedure in Example 1 (a) is repeated to prepare a solution of acrylamide containing 0.2% methone. The solution is allowed to stand overnight and then passed through a bed of activated carbon (Nuchar WV-L 8 x 30 mesh).

The resulting monomer, without any methone present, is polymerized in accordance with Example 2. The polymer product is dried at 90 ° C and has a viscosity as such above 2.8 and less than 2% insoluble substances.

Claims (20)

449 362 w PATENTKRAV 1. A composition characterized in that it consists of a monomer selected from acrylamide, acrylic acid, 2-acrylamido--2-methylpropanesulfonic acid and its salts, or mixtures thereof, and which monomer contains a compound which results in a harmful amount of an insoluble material in the polymerization thereof, and 0.001-2.0% by weight, based on the monomer, of a cyclic organic compound containing a 1,3-ol-c-cnz-c-dione moiety of the formula 2. A composition according to claim 1, characterized in that it further contains at least one further ethylenically unsaturated monomer having an ability to copolymerize therewith to form a water-soluble copolymer. A polymerized composition according to claim 1, characterized in that the 1,3-dione does not constitute a polymerization inhibitor. Composition according to any one of Claims 1 to 3, characterized in that the 1,3-dione is 5,5-dimethyl-1,3-cyclohexanedione or its tautomer 5,5-dimethyl-tetrahydro-m resorcinol_ Composition according to any one of claims 1 to 3, characterized in that the 1,3-dione is selected from the group consisting essentially of 1,3-cyclohexanedione, fluoroglycinol, barbituric acid, carboxymethoxydimedonene olate and carbethoxydimedonene enolate. A process for the preparation of a high molecular weight water-soluble polymer by polymerizing a monomer selected from acrylamide, acrylic acid, 2-acrylamido-2-methylpropanesulfonic acid and its salts, or mixtures thereof, and which monomer contains an impurity which normally results in a 449,362 31 harmful amount of an insoluble material in the polymerization thereof, characterized in that to the monomer before the polymerization is added 0.001-2.0% by weight, based on the monomer, of a cyclic organic compound which does not constitute a polymer. and which contains a 1,3-dione moiety of the formula OO -ë-CH -ë- 2. 7. A process according to claim 6, characterized in that the monomer is an aqueous solution containing about 40-60% by weight of acrylamide monomer when the 1,3-dione is added thereto. 8. A process according to claim 7, characterized in that the acrylamide solution is diluted to about 10-35% by weight of acrylamide before polymerization. 9. A process according to any one of claims 6-8, characterized in that the polymerization is a solution polymerization. 10. l0. The process of claim 9, wherein the 1,3-dione is present as about 0.03-0.4 weight percent of the monomer. 11. ll. Process according to Claim 9, characterized in that the product is dried after the polymerization. 12. A process according to claim 11, characterized in that the monomer is acrylamide and that the drying takes place at a temperature above about 8U ° C and urea is also added to the acrylamide before polymerization. 13. A process according to claim 6, characterized in that the polymerization is a water-in-oil emulsion polymerization. 449 362 32 14. The process of claim 13, wherein the 1,3-dione is present as about 0.3 to 1% by weight of the monomer. A process according to claim 13, characterized in that the 1,3-dione is used in an amount of about 0.005-0.2% by weight of the monomer and the mixture is aged at a temperature above about 50 ° C for more than about 2 hours. . Process according to one of Claims 6 to 15, characterized in that the 1,3-dione is 5,5-dimethyl-1,3-cyclohexanedione or its tautomer 5,5-dimethyl-tetrahydro-m resorcinol. 17. A process according to any one of claims 6-15, characterized in that the 1,3-dione is selected from a group consisting essentially of 1,3-cyclohexanedione, fluoroglucinol, barbituric acid, carbomethoxydimedonenolate and carbethoxydimedonenolate. 18. A process according to any one of claims 6-17, characterized in that at least one further ethylenically unsaturated monomer is copolymerized with the monomer to produce a water-soluble polymer. 19. A process according to any one of claims 6-18, characterized in that urea is added to the monomer before polymerization. Process according to one of Claims 6 to 18, characterized in that urea is added after polymerization and before drying. _ __.- f, ... ,,, _....__-, .... _._....._: _....._