GB1561727A

GB1561727A - Comprising water-soluble acrylamides polymers and water-soluble resinous amine condensation products

Info

Publication number: GB1561727A
Application number: GB48309/76A
Authority: GB
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 1975-11-20
Filing date: 1976-11-19
Publication date: 1980-02-27
Also published as: AT344991B; FR2332301A1; DE2552014A1; FR2332301B1; ATA862176A; IT1069828B; BE848540A; SE430619B; SE7612908L

Description

(54) MIXTURES COMPRISING WATER-SOLUBLE ACRYLAMIDE POLYMERS AND WATER-SOLUBLE RESINOUS AMINE CONDENSATION PRODUCTS (71) We, BASF AKTIENGESELLSCHAFT, a German Joint Stock Company of 6700 Ludwigshafen, Federal Republic of Germany, do hereby declare the invention, for which we pray that a Patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following Statement: The present invention relates to mixtures comprising a water-soluble, non-ionic or cationic polymer of acrylamide and a water-soluble, resinous amine condensation product.

Polyacrylamides, which are commercially available as powders, are most commonly used in the form of dilute aqueous solutions. The powder must therefore be dissolved in water.

This however frequently presents difficulties because the polymer easily forms lumps on introduction into water. The preparation of dilute polyacrylamide solutions by introducing, instead of the solid polymer, a water-in-oil dispersion, which contains the polyacrylamide in the dispersed aqueous phase, into water has also been disclosed. In this method, the acrylamide polymer dissolves very rapidly after phase inversion of the water-in-oil dispersion, without forming lumps.

German Patent 1,089,173 discloses the manufacture of water-in-oil dispersions containing acrylamide polymers by polymerizing a water-in-oil emulsion of an aqueous solution of acrylamide, which may be may not contain other water-soluble ethylenically unsaturated monomers, in a hydrophobic, organic dispersion medium in the presence of a polymerization initiator. Hydrocarbons and perchloroethylene are recommended as the hydrophobic organic dispersion medium which forms the continuous phase of the water-in-oil dispersions.

Water-in-oil dispersions of polyacrylamides are used, for example, as flocculating assistants for clarifying aqueous systems, in the manufacture of paper, in the treatment of communal and industrial effluents, as dispersing agents for protective colloids for drilling muds, and as assistants for the secondary extraction of petroleum from flooding waters.

Examples of resinous amine condensation products are polyalkyleneimines, alkylene polyaminelepichlorohydrin resins or reaction products af alkyleneimines with aminopolyamides. These products are commercially available as aqueous solutions of from 20 to 30% by weight strength. The viscosities of the commercially available solutions are from 100 to 10,000 mPa.s. The amine condensation products are as a rule additionally diluted with water before they are used, for example as drainage and retention aids.

Since even 5% by weight strength aqueous polyacrylamide solutions have such a high viscosity that they can no longer be pumped, or can only be pumped with difficulty, aqueous polyacrylamide solutions and aqueous solutions of resinous amine condensation products cannot be mixed with one another at will. Furthermore, there is the danger that because of the incompatibility of the two polymers, namely the polyacrylamides and the resinous amine condensation products, eg. polyalkyleneimines or alkylenepolyaminel epichlorohydrin resins, mixtures of aqueous solutions of these polymers may exhibit phase separation.

The present invention seeks to provide a mixture comprising a polyacrylamide and a resinous amine condensation product which is stable, and can be pumped, even if the polyacrylamide content predominates and the solids content is relatively high.

According to the invention there are provided mixtures, comprising a water-soluble, non-ionic or cationic polymer of acrylamide and a water-soluble resinous amine condensation product, wherein said ingredients are contained in the discontinuous phase of a water-in-oil dispersion. The polymer mixtures according to the invention generally contain from 95 to 40% by weight of the non-ionic or cationic acrylamide polymer and from 5 to 60% by weight of the resinous amine condensation product, based on the weight of the two ingredients together. The aqueous phase of the dispersion generally amounts to from 40 to 85% by weight , based on the total dispersion, and usually has a solids content of from 15 to 50% by weight.

Surprisingly, dilute aqueous solutions of the mixtures according to the invention exhibit a greater efficiency when used as flocculating agents, sedimentation assistants, drainage aids and retention aids, than do the individual polymeric products in the mixture, or than do combinations of aqueous solutions of the said polymers.

The aqueous phase of the dispersion is dispersed in a hydrophobic organic dispersion medium (referred to herein as "oil"). The latter can be, for example, one of the liquids described in German Patent 1,089,173, for example an aromatic liquid hydrocarbon, eg. toluene or xylene, perchloroethylene or an aliphatic liquid hydrocarbon, eg. a paraffin oil.

In general, saturated hydrocarbons boiling at from 120 to about 350"C are used. Pure hydrocarbons or mixtures of two or more hydrocarbons can be employed. A mixture of saturated hydrocarbons which contains up to 20% by weight of naphthenes is preferred.

The saturated hydrocarbons are n- and i-paraffins. The boiling range of the mixture (determined according to ASTM D-1078/86) is from 192 to 2540C.

In order to ensure that the dispersions according to the invention are stable to coagulation and sedimentation, they may contain a conventional water-in-oil emulsifier, eg. sorbitan monostearate, sorbitan monooleate, glycerol esters wherein the acid component is derived from carboxylic acids of 14 to 20 carbon atoms and sodium cetyl/stearly phthalate.

The emulsifiers which may be used for the above purpose generally have an HLB value of at most 8 and are usually present in the dispersion in amounts of from 0.1 to 30% by weight, preferably from 1 to 10% by weight. The HLB value is the hydrophilic-lipophilic balance of the emulsfier, ie. the balance of the size and strength of the hydrophilic and lipophilic groups of the emulsfier. A definition of this concept is to be found, for example, in "Das Atlas HLB-System", Atlas Chemie GmbH, EC 10 G, July 1971 and in Classification of Surface Active Agents by "HLB", W. C. Griffin, Journal of the Society of Cosmetic Chemists, (1950), 311.

Furthermore, the water-in-oil dispersions of the invention may additionally contain from 0.5 to 5% by weight of a wetting agent having an HLB value greater than 10, in order to ensure that they can be more rapidly diluted directly with water. These wetting agents are essentially hydrophilic water-soluble products, eg. oxyethylated alkylphenols, dialkyl esters of sodium sulfosuccinates in which alkyl is of at least 3 carbon atoms, soaps derived from fatty acids of 10 to 22 carbon atoms and alkali metal salts of alkyl-sulfates or alkenyl-sulfates of 10 to 26 carbon atoms. Oxyethylated nonylphenols having a degree of oxyethylation of from 6 to 20, oxyethylated nonylphenol-formaldehyde resins having a degree of oxyethylation of from 6 to 20, dioctyl esters of sodium sulfosuccinates and octylphenolpolyethoxyethanol are preferred.

The manufacture of water-in-oil dispersions of homopolymers and copolymers of acrylamide that are water-soluble and non-ionic or cationic may be carried out by conventional methods. Thus, the manufacture of such dispersions is described, for example, in German Patent 1,089,173, Belgian Patent 814,401, German Laid-Open Application 2,226,143 and German Laid-Open Application 2,344,018.

The homopolymers or copolymers of acrylamide contained in the dispersions of the invention are water-soluble. Their molecular weights are generally from 100,000 to 25,000,000 preferably from 1,000,000 to 25,000,000. The compounds which can be used as comonomers in the acrylamide copolymers are water-soluble and have an ethylenically unsaturated double bond. They may be non-ionic or neutralized or quaternized basic compounds, eg. esters of acrylic acid or methacrylic acid with amino alcohols or amides of acrylic acid or methacrylic acid with dialkylaminoalkylamines.

Further suitable cationic monomers are vinylimidazole and vinylpyridine. Monomers to be singled out particularly are dimthylaminoethyl acrylate, diethylaminoethyl acrylate, dimethylaminoethyl methacrylate, dibutylaminoethyl methacrylate, dimethylaminomethyl acrylate and methacrylte and diethylaminopropyl acrylate and methacrylate.

Further suitable ethylenically unsaturated water-soluble monomers are listed in U.S.

Patents 3,418,237, 3,259,570 and 3,171,805. The acrylamide copolymers generally contain up to 90% by weight, preferably from 2 to 50% by weight, of one comonomer or of a mixture of two or more comonomers.

Water-soluble resinous amine condensation products have also been disclosed, and are commercially available. They include, for example, water-soluble polyalkyleneimines, eg. polyethyleneimine, and water-soluble polyalkylenepolyamines; which are manufactured, for example, by condensing akylene dihalides with polyalkylenepolyamines of halohydrins with polyalkylene-polyamines. This category of condensation products also includes the reaction products of alkylene dihalides or halohydrins with ammonia. The preferred halohydrin is epichlorohydrin. Thus, alkyleneimine-epichlorohydrin resins may be used.

Further examples of resinous amine condensation products are the water-soluble condensates of polyamides and epichlorohydrin disclosed in German Patent 1,177,824, and condensation products which additionally contain caprolactam as copolymerized units. The resinous amine condensation products also include polyamidoamines, which may be obtained in the conventional manner by amidation of dicarboxylic acids with from 0.8 to 1.5 moles of diamines and/or polvamines in the presence or absence of aminocarboxylic acids and/or their lactams, and the reaction products of polyamidoamines with alkyleneimines, preferably ethyleneimine. Products of this nature containing grafted-on alkyleneimines are described, for example, in German Laid-Open Application 1,802,435. Further suitable resinous amine condensation products are obtained by reacting 1 mole of a polyether with 2 moles of ethylene chlorohydrin and, grafting ethyleneimine onto the condensation product.

It is also possible to employ, with advantage, amine condensation products which instead of containing grafted-on ethyleneimine have been reacted with a polyether-dichlorohydrin.

Further, it is possible to use the products which are obtained by reacting a polyamidoamine, to which ethyleneimine may or may not have been grafted, with polyalkylene oxide derivatives which are reacted, at the terminal OH groups, with at least equivalent amounts of epichlorohydrin.

The resinous amine condensation products are as a rule commercially available in the form of aqueous solutions of from 20 to 50% by weight strength. The viscosity of the 20% by weight strength aqueous solutions of the amine condensation products is usually from 100 to 2,000 mPa.s.

The water-in-oil dispersions of the invention may be manufactured by adding an aqueous solution, of from 20 to 50% by weight strength, of a water-soluble resinous amine condensation product to a water-in-oil dispersion of a water-soluble, non-ionic or cationic homopolymer or copolymer of acrylamide and emulsifying the aqueous solution. The aqueous solution of the amine condensation product may be emulsified in the water-in-oil dispersion of the acrylamide polymer by means of, for example, a homogenizer. In some cases it suffices to stir the mixture vigorously. The sequence of addition of the constitutents of the mixture is not critical. If the ratio of resinous amine condensation product to acrylamide polymer is high, the amount of continuous phase of the water-in-oil dispersion is advantageously increased to a level where the dispersions obtained can still be pumped.

The water-in-oil dispersions of the invention are stable, can contain a high proportion of polymer and can very easily be diluted with water, especially if they contain a wetting agent or if a wetting agent having an HLB value of more than 10 is added to the water used for dilution.

The water-in-oil dispersions of the invention can be used, for example, as a flocculating assistant for clarifying aqueous systems, in the manufacture of paper, in the treatment of effluents, as a dispersing agent and protective colloid for drilling muds and as an assistant for the secondary extraction of petroleum from flooding waters. In all cases where very dilute solutions are required the dispersions initially manufactured according to the invention may be diluted with water.

In the form of water-in-oil dispersions, mixtures of non-ionic or cationic homopolymers or copolymers of acrylamide with resinous amine condensation products are fluid and can nevertheless be produced in a pumpable form with more than 10% by weight solids content (based on total polymer content) without detrimental incompatibility manifesting itself between the individual components of the polymer mixture.

Furthermore, these mixtures exhibit a higher efficiency - based on polymer content - as flocculating agents, sedimentation agents, drainage aids and retention aids, than do the individual polymers components.

The Examples which follow illustrate the invention. In the Examples, parts are by weight and percentages are by weight based on the weight of the materials. The K values of the polymers in the Examples were measured by the method of H. Fikentscher, Cellulosechemie 13 (1932), 58 - 64 and 71 - 74, on an 0.1% by weight strength solution in 5% by weight strength aqueous NaCl solution at 250C; K = k . 103.

The viscosities in the Examples were measured in a Brookfield viscometer at 20 rpm.

The following water-soluble resinous amine condensation products were used in the Examples: Solution A A 20% by weight strength aqueous solution of a condensation product of a polyamidoamine (obtained from diethylenetriamine, triethylenetetramine and adipic acid) and ethyleneimine, which is crosslinked with epichliorohydrin, and has been manufactured as described in Example 2 of German Laid-Open Application 1,802,435.

Viscosity of the solution at 200C, 800 mPa.s; pH brought to 5 with sulfuric acid.

Solution B: A 20% by weight strength aqueous solution of a reaction product of an ethyleneiminegrafted polyamidoamine (obtained from diethylenetriamine and adipic acid) and an oxyethylated ethylene glycol (degree of oxyethylation = 40) which has been completely reacted with epichlorohydrin at the OH groups, the grafted polyamidoamine and modified ethylene glycol being used in the weight ratio of 3 : 2. Viscosity of a 20% by weight strength aqueous solution at 200C, 700 mPa.s; pH brought to 5 with sulfuric acid.

Solution C: 30% by weight strength aqueous solution of a polyethyleneimine; viscosity of a 20% by weight strength aqueous solution at 20"C, 2,500 mPa.s; pH brought to 5 with sulfuric acid.

Solution D: 18% by weight strength aqueous solution of a reaction product of a polyamidoamine obtained from diethylenetriamine and adipic acid) and an oxyethylated ethylene glycol (degree of oxyethylation = 45) which has been completely reacted with epichlorohydrin at the OH groups, the polyamidoamine and modified ethylene glycol being used in the weight ratio of 3 : 2. Viscosity of a 20% by weight strength aqueous solution at 200C, 900 mPa.s; Ph brought to 5 with sulfuric acid.

Solution E: 20% by weight strength aqueous solution of a reaction product of a polyamidoamine (obtained from diethylenetriamine and adipic acid) and epichlorohydrin, obtained as described in Example 1 of German Patent 1,177,824. Viscosity of a 20% by weight strength aqueous solution at 200C, 250 mPa.s; pH brought to 5 with sulfuric acid.

Example I A 20% strength aqueous solution A is emulsified, by means of an Ultraturrax, in a 25% strength water-in-oil dispersion of a copolymer of acrylamide with the sulfate of diethylaminoethyl acrylate. (Ultraturrax is a registered Trade Mark). The water-in-oil acrylamide copolymer dispersion was prepared by the method described in Example 3 of German Laid-Open Application 2,226,143, the composition of the said 25% strength water-in-oil dispersion of the cationic acrylamide copolymer being as follows: 25 parts of a copolymer of 0.846 mole % of acrylamide with 0.153 mole % of the sulfate of diethylaminoethyl acrylate, K value 190, 45 parts of water, 24 parts of a mixture of 84% of saturated aliphatic hydrocarbons and 16% of naphthenic hydrocarbons (boiling range of the mixture: 192 - 254"C), 3 parts of sorbitan monooleate, 1 part of oxyethylated nonylphenol (degree of oxyethylation 8-12) and 2 parts of oxyethylated castor oil.

In Examples 1 to 5, this water-in-oil dispersion is referred to as Dispersion A (it does not contain a resinous amine condensation product).

Up to a ratio of 1 part of dispersion A to from 0 to 1.1 parts of aqueous 20% strength solution A, the aqueous solution A can be emulsified in dispersion A without diluting the continuous organic phase of the latter, the proportion by weight of the discontinuous inner phase of the dispersion rising to above 80% by weight.

If a higher proportion of solution A in the total mixture is used, the proportion of continuous phase is increased, by adding sufficient of a mixture of 24 parts of a mixture of 84% of saturated aliphatic hydrocarbons and 16% of naphthenic hydrocarbons (boiling range of the mixture 192 - 254"C, 3 parts of sorbitan monooleate, 1 part of oxyethylated nonylphenol (degree of oxyethylation 8-12) and 2 parts of oxyethylated castor oil, so that the proportion of inner phase in the dispersion always remains below 80% by weight.

The dispersion A is thoroughly mixed with the resinous amine condensation products described above (solutions A to E), so that stable water-in-oil dispersions are obtained. The composition of the dispersions thus obtained, which contain the cationic polyacrylamide and the cationic amine condensates alongside one another in the discontinuous phase, is shown in Table 1.

Stable mixed dispersions are obtained in which, as may be seen from Examples 1.1.1 to 1.1.3 and Tables 2 to-5, a distinct synergistic effect manifests itself in the activity of the combination of both polymers when used as retention and drainage aids in the manufacture of pauper, and when used in flocculating communal sewage sludges.

Example 1.1.3 and Table 4 in addition show that the activity of the aqueous diluted mixed solution prepared from the water-in-oil combination dispersions manufactured as described above is significantly greater than the activity of a combination of separately manufactured dilute aqueous polyacrylamide solutions and a solution of a condensation product of a polyamidoamine and ethyleneimine, which is crosslinked with epichlorohydrin (this combination being prepared from dispersion A and solution A).

TABLE 1 Disper- Polyacrylamide type % by weight of resinous % by weight ratio of % by weight sion polyacrylamide amine of resinous polyacrylamide of inner in the condensate amine to resinous phase in the dispersion condensate amine dispersion in the condensate dispersion dispersion 100/0 70.0 A Cationic acrylamide 25.0 - copolymer of 0.846 B mole % of acrylamide 21.2 5.3 80/20 75.1 and 0.153 mole % of C the sulfate of 19.1 8.2 70/30 77.6 diethylaminoethyl D acrylate 16.9 Solution A 6.8 60/40 80.1 DA 10.7 16.1 40/60 76.6 DB 5.1 20.5 20/80 73.5 E 20.9 5.2 80/20 75.4 F 16.5 11.0 60/40 80.6 G 10.3 Solution B 15.5 40/60 77.5 GA 4.9 19.6 20/80 74.7 H 19.9 4.9 80/20 76.6 I 14.3 9.5 60/40 79.0 J 8.8 Solution C 13.2 40/60 78.3 K 4.2 16.8 20/80 79.0 TABLE 1 (continued) Disper- Polyacrylamide type % by weight of resinous % by weight ratio of % by weight sion polyacrylamide amine of resinous polyacrylamide of inner in the condensate amine to resinous phase in the dispersion condensate amine dispersion in the condensate dispersion in the dispersion L Cationic acrylamide 19.0 4.8 80/20 80.0 copolymer of 0.846 M mole% of acryl- 12.8 8.5 60/40 79.0 amide and 0.153 mole N % of the sulphate of 7.7 Solution E 11.5 40/60 79.0 diethylaminoethyl O acrylate 3.4 13.8 20/80 78.0 P 18.8 4.7 80/20 78.2 Q 12.4 8.3 60/40 79.3 R 7.2 Solution D 10.8 40/60 77.6 S 3.2 12.7 20/80 76.3 T Acrylamide 25.0 - - 100/0 70.0 homopolymer U 22.0 2.4 90/10 74.5 V 19.0 4.8 80/20 77.9 W 15.5 Solution A 6.6 70/30 77.2 X 12.3 8.2 60/40 76.1 Y 7.4 11.1 40/60 76.4 13.2 20/80 75.3 Z 3.3 1.1 Activity of the dispersions in the manufacture of paper 1.1.1 Retention effect A stock of 80% of bleached sulfite cellulose and 20% of china clay X1, with an initial freeness of 35 SR was prepared. Sheets weighing about 70 g/m2 were produced from this stock on a laboratory sheet-forming apparatus, using either 1.5% of alum (pH 4.8) or 0.5% of alum (pH 6.0). In these experiments, 0.015% by weight of polymer solids (pure polymers or the polymer mixtures according to the invention) was employed in the form of an 0.1% strength aqueous solution. The latter was prepared from the water-in-oil dispersions of the invention.

The ash content of the sheets produced was determined. Table 2 shows the superior synergistic effect. Only when the amount of solution A reaches 70%, does the ash content drop to the level obtained with pure cationic polyacrylamide, though the pure solution A alone shows a markedly weaker effect than the pure cationic polyacrylamide.

Table 2: Retention effect (polymer solids employed: 0.015% by weight] Product % ash in the sheet 1.4% of alum; 0.5% of alum; pH 4.8 pH 6.0 Comparative Examples: without additive 4.7 4.9 Dispersion A 12.9 12.8 Solution A 7.4 7.4 Examples according to the invention: Dispersion B 14.1 14.0 Dispersion C 14.0 13.9 Dispersion D 13.1 13.0 Dispersion DA 11.9 11.2 1.1.2 Acceleration of drainage A stock of 100% of waste paper, having an initial freeness of 59" SR, was prepared. The effect of adding polymer equivalent to 0.04% by weight of polymer solids on the freeness of this stock was measured in a Schopper-Riegler freeness tester. 0.04% by weight of polymer solids (pure polymers or the polymer mixtures according to the invention) was employed, in the form of 0.1% strength solution. The latter was prepared from the water-in-oil dispersions of the invention.

Table 3: Reduction in freeness [polymer solids employed: 0.04%] Product Freeness, "SR 1.5% of alum; no alum; pH 4.8 pH 7.0 Comparative Examples: without additive 54 59 Dispersion A 42 46 Solution A 35 45 Examples according to the invention: Dispersion B 30 39 Dispersion C 28 41 Dispersion D 25 37 Dispersion DA 27 37 Table 3 shows the superior synergistic effect. In the entire range investigated, the combination of the polymers, in the form of their water-in-oil dispersions, shows a significantly greater reduction of the freeness - which is up to 100SR - than do the pure components of the mixture.

1.1.3 Comparison of the effect of a dilute aqueous solution, prepared from the mixed dispersion of the invention (compare Table 1), with the effect of an aqueous solution prepared by mixing a dilute aqueous solution of the corresponding polyacrylamide with a dilute solution A.

The retention effect in the manufacture of paper was compared for both the above cases.

A stock of 80% of bleached sulfite cellulose and 20% of china clay Xl, having an initial freeness of 35"SR, was prepared. From this stock, sheets weighing about 70 g/m2 were produced on a laboratory sheet-forming apparatus in the presence of 1.5% of alum (pH 4.8). For this experiment, 0.015% by weight of polymer solids (pure polymer or the polymer mixtures according to the invention) was employed, in the form of an 0.1% strength aqueous solution. The latter was prepared from the water-in-oil dispersions of the invention.

The ash content of the sheets obtained was determined.

The measurements recorded are mean values from four samples.

Table 4 shows the superiority of the solution prepared from the water-in-oil mixed dispersions over the mixture of the aqueous solution of the individual components.

Table 4: Retention effect Product % ash in Standard the sheet deviation average value S Aqueous solution prepared directly from dispersion C 16.3 0.55 Comparative Examples: no additive 7.2 0.55 aqueous solution prepared by mixing 14.7 0.50 an 0.01% strength aqueous solution A and an 0.01% strength aqueous solution of a copolymer of 0.846 mole % of acrylamide and 0.153 mole % of the sulfate of diethylaminoethyl acrylate 1.2 Flock size obtained by flocculating a communal sewage sludge.

The flocculation of a digested sludge, containing 2.3% by weight of solids, from a communal sewage farm. The sludge solids had an ash content of 40.4% by weight.

The sludge, and defined amounts of polymer (pure polymer or polymer mixtures according to the invention), in the form of 0.1% strength aqueous solutions, were introduced into a 500 ml measuring cylinder. The solutions were prepared from the water-in-oil dispersions of the invention (compare Table 1).

The polymer solution was thoroughly mixed with the sludge by tilting the measuring cylinder to and fro six times, resulting in flocculation. The mixture was then filtered on a Bchner funnel (11 cm diameter) into which a circular filter had been inserted, and after a filtration time of 10 minutes the flock size of the sludge flocks was assessed visually, using a figure of merit scale from 1 (no flocculation) to 5 (very large, stable flocks).

Table 5: Flocculation of communal digested sludge.

Flocculation figures of merit from 1 (no flocculation) to 5 (very large, stable flocks) Product Flocculation on adding the stated amounts of polymer solids (g/m3 of sludge 100 150 200 250 300 350 400 Dispersion B 3 5 Dispersion D 4-5 5 Dispersion DA 3-4 5 Dispersion DB 2-3 4-5 5 Comparative Examples: Dispersion A 2 3 4-5 5 Solution A 1-2 1-2 1-2 1-2 Table 5 shows the superior synergistic effect. Only when the amount of solution A reaches 80% by weight is the effect reduced to the level of the pure cationic polyacrylamide, though the pure solution A by itself produces a substantially weaker flocculation effect than does the pure cationic polyacrylamide.

Example 2 Following the method described in Example 1, the 20% strength aqueous solution B was emulsified, by means of an Ultraturrax, in a 25% strength water-in-oil dispersion of a copolymer of acrylamide with the sulfate of diethylaminoethyl acrylate (molar ratio 0.846/0.153) (dispersion A).

The composition of the mixed dispersions obtained, which contain the cationic polyacrylamide and solution B alongside one another in the discontinuous phase, is shown in Table 1.

Stable mixed dispersions are obtained, in which, as may be seen from Examples 2.1 to 2.2 and Tables 6 to 8, a distinct synergistic effect manifests itself in the activity of the combination of both polymers when used as retention assistants and dewatering assistants in the manufacture of paper, and when used for flocculating communal sewage sludges.

2.1 Activity of the dispersion in the manufacture of paper.

2.1.1 Retention effect The test was carried out as described under Example 1.1.1.

Table 6 shows the superior synergistic effect. Only when the amount of solution B reaches 70% does the ash content drop to the level obtained with pure cationic polyacrylamide, though the pure solution B alone shows a markedly weaker effect than the pure cationic polyacrylamide.

Table 6: Retention effect [polymer solids employed: 0.015% by weight] Product % ash in the sheet 1.5% of alum; 0.5% of alum; pH 4.8 pH 6.0 Dispersion E 14.0 13.3 Dispersion F 14.1 13.1 Dispersion G 14.1 12.9 Dispersion GA 9.3 9.5 Comparative Examples: without additive 4.7 4.9 Dispersion A 12.9 12.8 Solution B 7.6 8.4 2.1.2. Acceleration of drainage.

The test was carried out as described under Example 1.1.2.

Table 7 shows the superior synergistic effect.

Table 7: Reduction in reeness [polymer solids employed: 0.04%] Product Freeness, "SR 1.5% of alum; no alum; pH 4.8 pH 7.0 Dispersion E 30 36 Dispersion F 26 34 Dispersion G 28 37 Dispersion GA 30 39 Comparative Examples: without additive 54 59 Dispersion A 42 46 Solution B 35 43 In the entire range investigated, the combination of the polymers, in the form of their water-in-oil dispersions, shows a greater reduction of the freeness - which is up to 9"SR than do the pure components of the mixture.

2.2 Flock size obtained by flocculating a communal sewage sludge.

The test was carried out as described under Example 1.2 Table 8 shows the superior synergistic effect. Only when the amount of solution B reaches 80% by weight is the effect reduced to the level of the pure cationic polyacrylamide reached, though the p Comparative experiments: Dispersion A 2 3 4-5 5 Solution B 1 1-2 1-2 1-2 Example 3 Following the method described in Example 1, the 20% strength aqueous solution C was emulsified, by means of an Ultraturrax, in a 25% strength water-in-oil dispersion of a copolymer of acrylamide with the sulfate of diethylaminoethyl acrylate (molar ratio 0.846/0.153) (dispersion A). The composition of the mixed dispersions obtained, which contain the cationic polyacrylamide and the polymer of solution C alongside one another in the discontinuous phase, is shown in Table 1.

Stable mixed dispersions are obtained, in which, as may be seen from Examples 3.1 to 3.2 and Tables 1 to 11, a distinct synergistic effect manifests itself in the activity of the combination of both polymers when used as retention and drainage aids in the manufacture of paper, and when used for flocculating communal sewage sludges.

3.1 Activity of the dispersion in the manufacture of paper.

3.1.1 Retention effect The test was carried out as described under Example 1.1.1.

Table 9 shows the superior synergistic effect. Only when the amount of the polymer of solution C reaches from 60 to 80% does the ash content drop to the level obtained with pure cationic polyacrylamide, though the pure solution C alone shows a markedly weaker effect than the pure cationic polyacrylamide.

Table 9: Retention effect [polymer solids employed: 0.015% by weight] Product % ash in the sheet 1.5% of alum; 0.5% of alum; pH 4.8 pH 6.0 Dispersion H 13.5 13.9 Dispersion I 13.9 13.2 Dispersion J 11.0 11.6 Dispersion K 11.1 10.8 Comparative Examples: without additive 4.2 4.9 Dispersion A 12.6 9.8 Solution C 6.5 5.9 3.1.2 Acceleration of drainage.

The test was carried out as described under Example 1.1.2 Table 10 shows the superior synergistic effect Table 10: Reduction in freeness [polymer solids employed: 0.04%] Product Freeness, "SR 1.5% of alum; no alum; pH 4.8 pH 7.0 Dispersion H 23 44 Dispersion I 25 45 Dispersion J 26 46 Dispersion K 28 46 Comparative Experiments: without additive 56 57 Dispersion A 32 50 Solution C 45 47 In the entire range investigated, the combination of the polymers, in the form of their water-in-oil dispersions, shows a greater reduction of the freeness - which is up to 90SR than do the pure components of the mixture.

3.2 Flock size obtained by flocculating a communal sewage sludge.

The test was carried out as described under Example 1.2.

Table 11 shows the superior synergistic effect. Only when the amount of the polymer of solution C reaches 80% is the effect reduced to the level of the pure cationic polyacrylamide, though the pure solution C by itself produces a substantially weaker flocculation effect than does the pure cationic polyacrylamide.

Table 11: Flocculation of communal digested sludge.

Flocculation figures of merit from 1 (no flocculation) to 5 (very large, stable flocks) Product Flocculation on adding the stated amounts of polymer solids (g/m3 of sludge) 100 150 200 250 300 350 400 Dispersion H 4 5 Dispersion I 4 5 Dispersion J 3 5 Dispersion K 3-4 5 Comparative Examples: Dispersion A 3-4 5 Solution C 1-2 1-2 1-2 1-2 Example 4 Following the method described in Example 1, the 20% strength aqueous solution D was emulsified, by means of an Ultraturrax, in a 25% strength water-in-oil dispersion of a copolymer of acrylamide with the sulfate of diethylarninoethyl acrylate (molar ratio 0.846/0.153) (dispersion A). The composition of the mixed dispersions obtained, which contain the cationic polyacrylamide and the polymer of solution D alongside one another in the discontinuous phase, is shown in Stable 1.

Stable mixed dispersions are obtained, in which, as may be seen from Examples 4.1 and 4.2 and Tables 12 and 13, a synergistic effect manifests itself in the activity of the combination of both polymers when used as retention and drainage aids in the manufacture of paper.

4.1 Retention effect The test was carried out as under Example 1.1.1.

Table 12: Retention effect [polymer solids employed: 0.015% by weight] Product % ash in the sheet 1.5% of alum; 0.5% of alum; pH 4.8 pH 6.0 Dispersion L 11.9 9.8 Dispersion M 12.3 10.5 Dispersion N 11.5 11.3 Dispersion 0 10.9 10.0 Comparative Examples: without additive 4.2 4.9 Dispersion A 12.6 9.8 Solution D 6.1 7.0 Table 12 shows that in spite of replacing up to 80% by weight of the more active cationic polyacrylamide in the mixture by the less active polymer of solution D, the high level of efficiency of the cationic polyacrylamide remains preserved.

4.2 Acceleration of drainage.

The test was carried out as described under Example 1.1.2.

Table 13: Reduction in freeness [polymer solids employed: 0.04%] Product Freeness, "SR 1.5% of alum; no alum; pH 4.8 pH 7.0 Dispersion L 28 48 Dispersion M 30 50 Dispersion N 31 50 Dispersion 0 37 53 Comparative Experiments: without additive 56 57 Dispersion A 32 50 Solution D 48 56 Table 13 shows that in spite of replacing up to 60% by weight of the more active cationic polyacrylamide in the mixture by the less active polymer of solution D, the higher level of activity of the cationic polyacrylamide is, surprisingly, retained.

Example 5 Following the method described in Example 1, the 20% strength aqueous solution E was emulsified, by means of an Ultraturrax, in a 25% strength water-in-oil dispersion of a copolymer of acrylamide with the sulfate of diethylaminoethyl acrylate (molar ratio 0.846/0.153) (dispersion A). The composition of the mixed dispersions obtained, which contain the cationic polyacrylamide and the polymer of solution E alongside one another in the discontinuous phase, is shown in Table 1.

Stable mixed dispersions are obtained, in which, as may be seen from Examples 5.1 and 5.2 and Tables 14 and 15, a synergistic effect manifests itself in the activity of the combination of both polymers when used as retention and drainage aids in the manufacture of paper.

5.1 Retention effect The test was carried out as under Example 1.1.1.

Table 14: Retention effect [polymer solids employed: 0.015% by weight] Product % ash in the sheet 1.5% of alum; 0.5% of alum; pH 4.8 pH 6.0 Dispersion P 14.0 14.5 Dispersion Q 14.8 13.8 Dispersion R 12.9 13.3 Dispersion S 13.2 11.9 Comparative Examples: without additive 5.0 45 Dispersion A 14.5 14.1 Solution E 9.1 9.2 Table 14 shows that in spite of replacing up to about 50% by weight of the more active cationic polyacrylamide in the mixture by the less active polymer of solution E, the high level of efficiency of the cationic polyacrylamide remains preserved.

5.2 Acceleration of drainage.

The test was carried out as described under Example 1.1.2.

Table 15: Reduction in freeness [polymer solids employed: 0.04%] Product Freeness, "SR 1.5% of alum; no alum pH 4.8 pH 7.0 Dispersion P 29 46 Dispersion Q 27 42 Dispersion R 28 43 Dispersion S 33 45 Comparative Examples: without additive 53 58 Dispersion A 31 47 Solution E 38 48 Table 15 shows that in spite of replacing up to 60% by weight of the more active cationic polyacrylamide in the mixture by the less active polymer of solution E, a slight improvement in the level of activity of the cationic polyacrylamide occurs.

Example 6 Following the method described in Example 1, a 20% strength aqueous solution A was emulsified, by means of an Ultraturrax, in a 25% strength water-in-oil dispersion of a homopolymer of acrylamide (dispersion T). The composition of the resulting mixed dispersions, which contain the acrylamide homopolymer and the polymer of solution A alongside one another in the discontinuous phase, is shown in Table 1.

Stable mixed dispersions are obtained, in which, as may be seen from Examples 6.1 and Table 16, a synergistic effect manifests itself in the activity of the combination of both polymers when used as retention assistants in the manufacture of paper.

6.1 Retention effect The test was carried out as described under Example 1.1.1.

Table 16: Retention effect [polymer solids employed: 0.015% by weight] Product % ash in the sheet 1.5% of alum; 0.5% of alum; pH 4.8 pH 6.0 -- Dispersion U 13.0 12.7 Dispersion V 12.0 12.5 Dispersion W 11.8 12.1 Dispersion X 11.7 11.3 Dispersion Y 10.8 11.0 Dispersion Z 10.0 8.1 Comparative Examples: without additive 5.1 4.8 Dispersion T 12.7 13.0 Solution A 8.8 7.4 Table 16 shows that in spite of replacing up to about 50% by weight of the more active cationic polyacrylamide in the mixture by the less active polymer of solution A, the relatively high level of efficiency of the polyacrylamide remains preserved.

Claims

WHAT WE CLAIM IS:

1. A mixture comprising a water-soluble, non-ionic or cationic polymer of acrylamide and a water-soluble resinous amine condensation product, wherein said ingredienfs are contained in the discontinuous phase of a water-in-oil dispersion.

2. A mixture as claimed in claim 1, which contains from 95 to 40% by weight of the non-ionic or cationic acrylamide polymer and from 5 to 60% by weight of the resinous amine condensation product, based on the weight of the two ingredient together.

3. A mixture as claimed in claim 1 or 2, wherein the aqueous phase of the dispersion amounts to from 40 to 85% by weight, based on the total dispersion, and has a solids content of from 15 to 50% by weight.

4. A mixture as claimed in any of claims 1 to 3, wherein a cationic acrylamide copolymer is used which contains units of an ester of acrylic acid or methacrylic acid with an amonoalcohol or of an amide of acrylic acid or methacrylic acid with a dialkylaminoalkylamine as copolymerized units.

5. A mixture as claimed in any of claims 1 to 4, wherein the water-soluble resinous amine condensation product is a polyalkyleneimine, an alkyleneimine-epichlorohydrin resin, a polyamidoamine or a reaction product of an alkyleneimine with a polyamidoamine.

6. A mixture as claimed in any of claims 1 to 4, wherein the resinous amine condensation product is one substantially as hereinbefore described in any one of Solutions A to E.

7. A mixture as claimed in any of claims 1 to 6, wherein the dispersion contains from 0.1 to 30% by weight of a water-in-oil emulsifier having an HLB value of at most 8.

8. A mixture as claimed in any of claims 1 to 7, wherein the dispersion contains from 0.5 to 5% by weight of a wetting agent having an HLB value greater than 10.

9. A mixture as claimed in any of claims 1 to 8, when manufactured by a method comprising forming a water-in-oil dispersion of a water-soluble, non-ionic or cationic homopolymer or copolymer of acrylamide containing the polymer in the discontinuous phase and mixing therewith an aqueous solution of from 20 to 50% by weight strength of a water-soluble resinous amine condensation product.

10. A mixture as claimed in claim 1 and substantially as described in any of the foregoing Examples 1 to 6.

11. A product obtained by diluting a mixture as claimed in any of claims 1 to 10 with water.

12. The use of a product as claimed in claim 11 as a flocculating assistant for clarifying aqueous systems, in the manufacture of paper, in the treatment of effluents, as a dispersing agent and protective colloid for drilling muds or as an assistant for the secondary extraction of petroleum from flooding waters.

13. A process for the manufacture of paper including the step of draining a fibrous pulp on a papermaking machine, wherein a product as claimed in claim 11 is employed as an assistant in the draining step.