FI70230C - RAKKEDJIGA BASISKA POLYMERISAT FOERFARANDE FOER DERAS FRAMSTAELLNING OCH DERAS ANVAENDNING - Google Patents

Description

70230

Straight-chain basic polymers, process for their preparation and their use

DE 17 20 737 5 discloses a process for the preparation of basic polymers in which poly-N-vinyl-N-methylcarboxylic acid amides are subjected to acid hydrolysis at elevated temperature. Basic polymers with secondary amino groups are obtained. Although the hydrolysis of the formyl-10 compounds takes place at a sufficiently rapid rate at 100-110 ° C, only a degree of hydrolysis of only about 62 mol% is obtained (according to Example 2) with stoichiometric amounts of hydrochloric acid at about 100 ° C.

For a degree of hydrolysis of 93 mol%, 2.6 to 15 moles of hydrochloric acid per mole of formyl group equivalent at 108-109 ° C are required (Example 1). As a result, the polymers change in partially undesired amounts.

It is known from German application DE 16 92 854 20 to add polymers of N-vinyl-N-methylcarboxylic acid amides as dewatering aids to the pulp in order to improve the dewatering rate in papermaking. However, there is room for improvement in the effectiveness of these dewatering aids.

It is known from U.S. Pat. No. 4,217,214 to use polyvinylamine hydrochloride having a molecular weight greater than 3 x 10 as a flocculant for water-suspended particles and for the treatment of wastewater and sludges. Polyvinylamine hydrochloride is prepared according to the data of 30 patents by reacting acetaldehyde and acetamide to ethylidene-bis-acetamide, which is thermally cleaved to N-vinylacetamide and acetamide, by polymerizing N-vinylacetamide and hydrolyzing poly-N-vinyl acetate. Although polyvinylamine-35 hydrochloride is a good flocculant, the efficiency of this product in the treatment of sludges still needs to be improved.

It is an object of the present invention to provide straight-chain, basic polymers which, when polymerized, contain as a characteristic component units of the formula: -CH - CH-

NH

10 and which, when used as a retention aid, dewatering aid and flocculant in papermaking or sludge flocculation, give improved results compared to known basic polymers.

The object is solved according to the invention by straight-chain, basic polymers which are characterized in that they contain from 10 to 90 mol% of units of the formula:

-CH -CH-3 I

NH-CHO

and that their K-value according to Fikentscher is 10-200 22 (measured in 0.5% aqueous saline at 25 ° C).

The preparation of a compound of the formula CH2 = CH-NH-CHO (N-vinylformamide) is described for the first time in German Offenlegungsschrift DE 12 24 304. The homopolymerization of N-vinyl-3q formamide has not been known so far. It has now been discovered that N-vinylformamide can be polymerized using radical polymerization initiators, e.g. peroxides, hydrogen peroxides, reductive catalysts or radically decomposable azo compounds. Preferably, the azo compounds used for the polymerization are those disclosed for this purpose in the application 3 70230 DE 14 95 692. The polymerization is carried out in a solvent or diluent in the temperature range from 30 to 140 ° C. Depending on the polymerization conditions, polymers with different molecular weights are obtained, which in the following are characterized by K-values according to Fikentscher.

The K-value can vary within wide limits, for example between 10-200. Polymers with a high K value, e.g. above 80, are preferably prepared by polymerizing N-vinylformamide in water. Polymers with a low 10 K value, e.g. less than 80, are obtained when the polymerization is carried out in the presence of known polymerization regulators or in a solvent which regulates polymerization, e.g. in alcohols such as methanol, ethanol, n- and isopropanol and acetone and methylethyl. In 15 ketones. Other polymerization regulators include, for example, hydroxylammonium salts, chlorinated hydrocarbons, and thio compounds such as dodecyl mercaptan. Polymers with a low K value can be obtained, for example, by polymerizing N-vinylformamide in isopropanol using soluble polymerization initiators based on azo compounds. One particularly suitable azo compound for polymerization in isopropanol is, for example, 2,2'-azo-bis- (isobutyronitrile). For the preparation of high molecular weight polymers of N-vinyl formamide, water-soluble azo compounds are used, e.g. 2,2'-azo-bis (2-amidinopropane) hydrochloride and 4,4'-azo-bis- (4'-cyano- pentanoic acid), whereupon the reaction is carried out in aqueous solution. In addition to solution polymerization in water, a water-soluble solvent, mixtures of water and a water-soluble solvent, the polymerization can also take place in a water-immiscible solvent such as water-in-oil emulsion polymerization. Reverse suspension polymerization to produce finely divided polymers is also possible. The pH in the polymerization - if working in an aqueous medium - is between 4-9, preferably between 5-7. In solution polymerization, polymer solutions with a dry matter content of 5 to 50, preferably 3 to 30% by weight, are predominantly prepared.

From the reaction products obtained in the polymerization, poly- (1-aminoethylene) is prepared by solvolysis, cleaving the formyl group in the temperature range of 5 to 200, preferably 40 to 180 ° C in the presence of acids or bases. The solvolysis is preferably carried out at a temperature in the range of 70-90 ° C. About 0.05 to 1.5 equivalents (equivalent to 10 grams equivalent to 1 or the equivalent of 1 or more) of an acid such as hydrochloric acid, hydrobromic acid are required per equivalent of formyl group in poly-N-vinylformamide. , phosphoric acid and sulfuric acid. The pH in acid hydrolysis is between 5-0, preferably between 3-0. It can be set either by adding a carboxylic acid such as formic acid, acetic acid or propionic acid, a sulfonic acid such as benzenesulfonic acid or toluenesulfonic acid or an inorganic acid such as hydrochloric acid, sulfuric acid, phosphoric acid or hydrobromic acid. The hydrolysis takes place substantially faster than the hydrolysis of N-methyl-N-vinylformamide polymers and can thus be carried out under milder conditions, i.e. at lower temperatures and without excess acids.

In addition, the solvolysis of the foryl groups of poly-N-vinylformamide can also be carried out in a basic medium, e.g. in the pH range of 9-14. This pH is preferably adjusted by the addition of NaOH or KOH. However, it is also possible to use ammonia, amines and alkali metal bases, e.g. calcium hydroxide. For basic hydrolysis, 0.05-1.5, preferably 0.4-1.0 equivalents of 30 bases are used.

The cleavage of the formyl group can take place in various solvents, e.g. water, alcohols, ammonia and amines or e.g. in mixtures of water and alcohols or in aqueous solutions of ammonia and / or amines. In some cases, it may be advantageous to carry out the solvolysis in an inert diluent, e.g. dioxane, aliphatic or aromatic hydrocarbons. In all cases, poly- (1-aminoethylene) is obtained. In the hydrolysis, i.e. the formyl group is cleaved in water with acids or bases from poly-N-vinylformamide, formic acid or salts of formic acid are obtained as a by-product. In sol-volume alcohols - as well as in the presence of acids or bases - formic acid esters are formed as a by-product, while in solvolysis in amokia or amines formamide or substituted formamides are obtained. Particularly suitable solvents for the solvolysis are low boiling alcohols such as methanol, ethanol, isopropanol, n-propanol, n-butanol and isobutanol.

By-products of solvolysis can be removed from the system either during or after cessation of solvolysis. Thus, for example, when alcohol is used as a solvent, it is possible to azeotropically remove the formed formic acid esters from the reaction mixture, in which case it may be necessary to use a release agent. Also in the case of hydrolysis, the by-product (formic acid) can be removed from the system during or after the completion of the hydrolysis. Preferably, the polyvinylformamides are hydrolyzed with NaOH or hydrochloric acid at a temperature in the range of 70-90 ° C in aqueous solution. The K value of the hydrolyzed polymers corresponds to the K value of the non-hydrolyzed homopolymers of N-vinylformamide.

The polyvinylformamides are then partially hydrolyzed so that 10-90, preferably 20-90% of the formyl groups of the polyvinylformamide are cleaved. In this way, polymers are obtained which contain a statistically distributed unit of 9 to 10 mol% of units of the formula: -CH2-CH- and NH2 of 10 to 90 mol% of units of the formula: 35 6 70230 -ch9- ch-

^ I

NH-CHO

and which can be characterized, for example, by the following 5 formulas:

CH - CH - CH9-CH

10 n V 1-n L J "/ ^ 0 nh9 nhc ^

^ H

wherein n is a number between 0.9 and 0.1, preferably between 0.2 and 0.9.

The hydrolysis depends on the reaction conditions. It can be carried out at normal pressure, under reduced pressure or also at higher pressure. Aqueous or alcoholic solutions are obtained from which the polymer can be isolated after separation of the low molecular weight components. However, aqueous or alcoholic solutions obtained in the solvolysis can also be used directly as retention aids, dewatering aids and flocculants in papermaking or as flocculants for slurries. These polymers have excellent efficacy and exceed the efficacy of known commercial products such as polyethyleneimines or ethyleneimine-modified polyamide amines. Hydrolysis with bases gives polymers with free amino groups, while hydrolysis with acids gives the corresponding polymer salts, which, however, after the addition of bases such as NaOH or KOH, also form polymers with free amino groups.

The straight-chain basic poly-35 dimers of the invention are used to accelerate dewatering from wet 70230 nonwoven mats and to increase the retention of fines and fillers on pulp fibers in papermaking. Faster dewatering of the stock with a paper machine makes it possible to increase the speed of the paper machine and thus the production.

In addition, these compounds enable better web formation and further reduce the water content of the wet paper, so that less energy is required to dry the web than with the prior art dewatering and retention agents.

10 Improved papermaking retention saves raw material, allows cheaper fillers to be used instead of more expensive fiber materials, lightens the paper mill's water circulation load, and provides better printability of paper due to better and more even adhesion of fines and fillers. Improved retention also results in fewer substances entering the wastewater.

The poly- (1-aminoethylenes) obtained in the solvolysis of poly-N-vinylformamides are added in an amount of 0.005 to 0.5, preferably 0.01 to 0.1% by weight, based on dry fiber, to the stock before forming the web for papermaking. Particularly advantageous effects are then obtained with basic polymers with a K value of more than 80.

The polymers according to the invention are also used for the treatment of sludges from conventional water treatment plants or industrial water treatment plants. Polymers with K values up to 80,200 are preferably suitable for this. The sludges contain 30 questions about the substances that have settled to the bottom of the treatment plants during the clarification of the wastewater. The dry matter content of the slurries is between about 2-8% by weight. By adding the polymers used according to the invention to sludges, in particular sludges from municipal water treatment plants, it is possible to obtain a well-filtered or centrifugal residue with a high dry matter content of up to about 30% by weight. Flocculants are used in an amount of 100-350 g / cm of slurry. It is necessary to distribute the flocculant well into the slurry. This takes place, for example, in a mixing drum. The effect of flocculation-5 begins practically immediately after the addition of flocculant. The increase in particle size of flocculated solids can be observed. The water is separated from the residue by means of ordinary equipment such as sieve presses or centrifuges. The residue can then be stored in a warehouse or 10 can also be incinerated.

The K value of the polymers was measured according to H. Fikentscher, Cellulosechemie 13, 58-64 and 71-74 (1932) in 0.5% aqueous saline at 25 ° C; then means K = k.10.

15 1. Preparation of polymers

Example 1.1

In a beaker equipped with a stirrer, thermometer and apparatus for working under a nitrogen atmosphere, 80 g (1125 mM) of vinylform-20-amide was dissolved in 385 g of water. To this was added 1.3 g (4.8 mM) of 2,2'-azo-bis (2-amidinpropan) hydrochloride was deoxygenated with nitrogen and heated to the reaction mixture during half an hour at 60 ° C. This temperature was maintained for 5 hours. Thereafter, the reaction was 99.3%.

To the viscous polymer solution thus obtained (K value 81) was then added 450 g of 10% NaOH (1125 mM) and heated at 80 ° C for 5 hours. This gave a polymer in which all the formyl groups were cleaved (degree of hydrolysis = 90%). A total of 916 g of an aqueous polymer solution with a viscosity of 140 mPas (Brookfield, 25 ° C) was obtained.

Example 1.2

In the apparatus described in Example 1, 80 g of N-vinylformamide was dissolved in 385 g of water and polymerized with 655 g of 2,2'-azo-bis- (2-amidinopropane) hydrochloride over 5 hours at 55 ° C. 98.1 -% of

II

9 70230 reaction. The resulting polymer (K value 95) was heated with 23 g of 36% hydrochloric acid (227 mM) for 3 hours at 80 ° C. 489 g of a polymer solution were obtained in which the formyl groups in the polymer had been cleaved to 20%. The viscosity of the solution was 16,000 mPas (Brookfield, 25 ° C).

Example 1.3

In the apparatus shown in Example 1, 80 g of N-vinylformamide was dissolved in 385 g of water, 0.65 g of the azo compound of Example 1 was added as a polymerization initiator, and heated to 55 ° C for one hour. The polymerization was carried out for 5 hours at 55 ° C. To complete the reaction, the reaction mixture was heated at 60 ° C for an additional half hour at the end of the polymerization time. In this case, the reaction was 100 ° C.

The polymer thus obtained (K value 120) was then hydrolyzed with 68.5 g of 36% hydrochloric acid (676 mM) for 2 hours at 90 ° C. 534.5 g of an aqueous polymer solution with a viscosity of 10,500 mPas (Brookfield, 20-25 ° C) were obtained. 60% of the formyl groups of the hydrolysed polymer were cleaved.

Example 1.4

In a beaker equipped with a stirrer, thermometer and apparatus for working under a nitrogen atmosphere, 1410.8 g of N-vinylformamide was dissolved in 7888.4 g of water. To this was added 8.07 g of 2,2'-azobis- (2-amidinopropane) hydrochloride, oxygen was removed by bubbling nitrogen, and the reaction mixture was heated to 50 ° C for 1.4 hours. This temperature was maintained for 7 to 30 hours. Thereafter, the reaction was 99.6%.

The viscous polymer solution thus obtained (K-value of the homopolymer was 120) was then heated with 1715.4 g of concentrated hydrochloric acid for 4 hours at 90 ° C. A polymer containing 10 mole% of N-vi-35 vinylformamide and 90 mole% of N-vinylamine units was copolymerized (90% of the formamide groups of the polymer were hydrolyzed, K value was 120) -Example 1.5

In the apparatus described in Example 1.4, 1410.8 g of N-vinylformamide were polymerized in 7888.4 ml of water at 50 ° C using 2,2'-azobis- (2-amidinopropane) hydrochloride as the polymerization initiator. The polymerization was complete after 7 hours, the reaction was 99.6%.

To the viscous polymer solution (polymer K value 120) was added 1143.6 g of concentrated hydrochloric acid 10, and the reaction mixture was heated at 90 ° C for 4 hours. A polymer containing 40 mole% of N-vinylformamide units and 60 mole% of aminoethylene units was copolymerized (60% of the N-formyl groups were hydrolyzed, K value 120).

15 Example 1.6 (comparison)

Polydimethylaminoethyl methacrylate hydrochloride having a K value of 160 was used as the flocculant according to the prior art.

2a. Use of the polymer as a retention aid, dewatering aid and flocculant. The following polymers were used:

Polymer I; Commercially available high molecular weight polyethyleneimine

Polymer II: Polyamideamine obtained from adipine ha-25 Posta and diethylenetriamine inoculated with ethyleneimine and crosslinked with polyethylene glycol dichlorohydrin ether with 9 ethylene oxide units, cf. Example 3 in DE 2 434 816. Polymer III: Polymer of Example 1.3 Polymer IV; Polymer of Example 1.2 Polymer V: Polymer of Example 1.1 Polymer VI; The polymer of Example 1.3, however, was polymerized only up to a K value of 102 and 82% of the formyl groups were hydrolyzed off by saponification with hydrochloric acid.

11 70230

Polymer VII: A polymer obtained from N-methyl-N-vinylformamide with a K value of 106 and saponified up to 75% with hydrochloric acid (prepared according to Example 2 in DE 16 92 854).

Example 2: To 1 liter of wood and kaolin-containing newsprint pulp having a consistency of 2 g / l and a pH of 7.8, different amounts of different amounts of test polymers were added and the infiltration resistance was determined using a Schopper-Riegler instrument. SR as well as the dewatering time, i.e. the time when 700 ml of underwater water ran from the device. The polymers used and the results obtained with them are shown in Table 1.

Table 1 15 Leaching resistance (SR) and dewatering time (S) with polymer addition 0.02% 0.06% 0.1% 0.02% 0.06% 0.1%

Without addition 64 99.2

Polymer I

(comparison) 57 45 40 75.2 47.4 39.4

Polymer II

(comparison) 54 40 36 67.2 39.6 32.5

Polymer III (according to the invention) 46 33 30 51.0 28.8 24.8 25

Example 2.2

To test the dewatering accelerating effect of polymer V, the procedure was as in Example 1. For comparison, polymer II was used in the prior art. The results for 30 are shown in Table 2.

Table 2

Leaching resistance (SR) and dewatering time (S) With polymer addition 35 12 70230 0.06% 0.1% 0.06% 0.1%

Without addition 66 107.5

Polymer II

(comparison) 50 41 56.8 41.4

Polymer V 47 38 51.0 36.3

Example 2.3 Various amounts of the polymers shown in Table 3 were added to 1 liter of pulp containing 80% bleached sulfite pulp and 20% kaolin containing 0.5% 10 alum and having a pulp pH of 6 and paper sheets were prepared on a Rapid-Köthen sheeting machine. . The basis weight of the paper sheets and the filler content, which was determined to be ash by incineration, are the criteria for evaluating the efficiency of the 15 polymers. The higher the basis weight and filler content of the paper sheets, the better the effectiveness of the retention agent must be evaluated.

Table 3 2 20 Weight per square meter (g / cm) and ash content (%) with polymer addition 0.02% 0.04% 0.06% 0.02% 0.04% 0.06%

Excluding 58.0 4.2

_ _ Polymer I

(vert.) 61.3 62.1 62.6 7.7 9.1 9.7

Polymer II

(vert.) 62.3 64.1 64.5 9.6 11.7 12.0

Polymer III

67.6 69.9 70.8 12.0 14.7 14.7 30

Example 2.4 Filler retention was determined for a paper stock consisting of 80% bleached sulfite pulp and 20% kaolin and containing 1.5% alum. The pH of the paper stock 35 was 4.8. Filler retention was determined from the figures in Example 3. The effectiveness of polymer 13 70230 IV was compared with known retention aids I and II. The results are summarized in Table 4.

Table 4 5 Ash content with polymer addition 0.02% 0.04% 0.06%

Without increase 3.7

Polymer I

(comparison) 5.8 6.3 7.0

Polymer II

^ (comparison) 8.8 9.5 9.9

Polymer IV 10.9 11.9 12.6

Example 2.5

To determine the flocculating effect of the polymers according to the invention and the clarification of the effluent, a pulp-rich pulp containing 1 g of sulphite pulp and 0.25 g of kaolin per liter was mixed with various amounts of the polymers shown in Table 5. After stirring and settling the suspension, the transparency of the respective clear water was determined photometrically. The results are summarized in Table 5.

Table 5 25 Transparency (%) with polymer addition 0.02% 0.04%

Without increase 19.0

Polymer I

(comparison) 42.0 60.8

30 Polymer II

(comparison) 41.9 52.1

Polymer III 57.5 77.8

Example 2.6 To 1 liter of wood and kaolin-containing newspaper stock with a consistency of 2 g / l and a pH of 7.8, 14,70230 different amounts of test polymers were added and the infiltration resistance (SR) was determined using a Schopper-Riegler apparatus. dewatering time, i.e. the time during which 700 ml of wire water runs from the device. Table 6 shows the polymers used and the results obtained with them.

Table 6

Leaching resistance (SR) and dewatering time (S) with polymer addition 10 0.02% 0.06% 0.1% 0.02% 0.06% 0.1%

Without addition 62 99.3 61 101.0

Polymer II 51 38 34 68.0 40.1 34.0 (trans) 51 39 34 68.2 40.2 34.0 ie Polymer VII 50 50 50 66.8 64.6 66.0 (comparison) 50 49 50 66.5 63.8 67.0

Polymer VI 49 34 31 61.4 33.4 29.3 49 33 31 62.0 32.3 29.5

The polymer VI used according to the invention

The efficiency compared to the closest in the prior art (polymer VII) has been improved in a way that was not foreseeable in advance.

Example 2.7 Filler retention was determined on a paper pulp-25a consisting of 80% bleached sulfite pulp and 20% kaolin and containing 0.5% alum. The pH of the paper stock was 6.0. Various amounts of the polymers shown in Table 7 were added to one liter of this stock, and then paper sheets were prepared on a Rapid-Köthen sheeting machine. The filler content of the paper sheets, determined as ash by incineration, is one of the criteria for the effectiveness of the polymer as a retention aid.

Il 70230

Table 7

Ash content with polymer addition 0.02% 0.04% 0.06% 5 Without addition 3.7

Polymer II

(comparison) 9.3 10.6 11/5

Polymer VII

(comparison) 10.0 9.8 9.9

Polymer VI 9.6 12.1 13.1 10 2b. Use of polymers as flocculants for slurries

0.1% aqueous solutions were prepared from the polymer of Examples 1.4, 1.5 and 1.6 and tested as flocculants for the clarification slurry. The following test methods were used: a) Determination of flocculation rate and filtration rate 500 ml of sewage sludge were mixed in a 1 liter graduated cylinder with certain amounts of 0.1% aqueous flocculant solution. Flocculation occurred during thorough mixing. The contents of the measuring cylinder are then emptied into a Biichner funnel and filtered. Based on the filter, flocculation is assessed on the basis of vision. In this case, meant: 2 5 barely visible flocculation = flocculation rate 1 slight flocculation = 2 moderate flocculation = 3 good flocculation, mostly sufficient for practice = - "- 4 very good, optimal flocculation = -" -

Simultaneously, the amount of filtrate was measured after 30, 60, 90 and 120 seconds.

(b) Flocculation efficiency 35 In this test, the amount of flocculant which must be added to a slurry in a 1 liter graduated cylinder must also be determined in order to achieve optimum flocculation (flocculation number = 5).

Example 3

From the 5 wet sludges obtained from the municipal water treatment plant, the flocculation efficiency was determined for the polymers of Examples 1.4 and 1.5 compared to the polymer of Example 1.6 according to the method described in b) above. For the polymerization of Example 1.4, 200 10 mg / l of slurry was required for optimal flocculation, for the polymer of Example 1.5 150 mg / l, while when using the polymer of Example 1.6, 250 mg / l of slurry had to be used.

The polymers of Examples 1.4 and 1.5 were significantly more effective than the prior art polymer.

Example 4

With the wet sludge from the municipal water treatment plant, the flocculation rate and filtration rate were determined for the polymers of Examples 1.4 and 1.5 compared to the polymer of Example 1.6 in 2Q according to the method described in a) above:

Polymer Addition Flocculation- Amount of filtrate in ml after elution of the example amount 3Q 90 120 ^ mg / l _sludge_ 2 5 1.4 100 3-4 1.4 150 4-5 1.4 200 5 310 360 370 375 1.5 50 3-4 1.5 100 4 30 1.5 150 5 325 370 380 390

Comparison 1.6 150 3 1.6 200 4 1.6 250 5 230 325 350 370

Claims (7)

17 70230 Straight-chain basic polymers, characterized in that they contain from 9 to 10 mol% of units of the formula: -CH 2 -CH- and from 10 to 90 mol% of units of the formula: -CH 9 -ch- ^ I NH-CHO 15 and that their K-value according to Fikentscher is 10-200 (measured in 0.5% aqueous saline at 25 ° C). Process for the preparation of straight-chain basic polymers according to Claim 1, characterized in that the compound of the formula CH 2 = CH-NH-CHO (N-vinylformamide) is polymerized in the presence of radical polymerization initiators to polyvinylformamides and the polymers thus obtained At temperatures of 20-200 ° C in the presence of acids or bases, 10-90% of the formyl groups of the N-vinylformamide homopolymer are solvolyzed. Process according to Claim 2, characterized in that the vinylformamide is polymerized in aqueous solution using polymerization initiators based on water-soluble azo compounds, and the polymers thus prepared are solvolysed in alcohol or water. Process according to Claims 2 and 3, characterized in that 0.05 to 1.5 equivalents of mineral acid or base are used per formyl group equivalent of the poly (1870230) vinylformalide obtained in the polymerization. Process according to Claim 4, characterized in that 0.4 to 1 equivalent of mineral acid is used per formyl group equivalent of the polyvinylformamide obtained in the polymerization. Process according to Claim 4, characterized in that 0.4 to 1 equivalent of base is used per formyl group equivalent of the polyvinylformamides. Use of straight-chain basic polymers according to Claim 1 as retention aids, dewatering aids and flocculants in papermaking or as flocculants for slurries. li 19 70230