NO822030L - PROCEDURE FOR THE PREPARATION OF Aqueous-POLYMERS OF DI-C1- TO C3-ALKYLAMINO-NEOPENTYL (MET) ACRYLATES, AND THEIR USE - Google Patents

Description

A method is known from BRD pateht 24 32 699

for the production of sedimentation-stable water-in-oil dispersions of acrylamide polymers, whereby a water-in-oil emulsion is polymerized from an aqueous acrylamide solution which optionally contains up to 50% by weight of other water-soluble, ethylenically unsaturated monomers, in a hydrophobic organic dispersion medium in the presence of a water-in-oil emulsifier, 0.1-10% by weight of a wetting agent whose HLB value is above 10, and a polymerization initiator. As other water-soluble, ethylenically unsaturated monomers, esters of amino alcohols of acrylic acid or methacrylic acid also come into consideration. The known copolymers are also used, among other things, in paper production to increase the retention, the dewatering rate and the fluffing rate. However, the effects achieved with these copolymers may still need to be improved.

From BRD-off.skrift 29 34 086, emulsion polymers are known which contain (a) 5-100% by weight of a dialkylamino-neopentyl ester of an ethylenically unsaturated polymerizable carboxylic acid and (b) 0-95% by weight of a water highly limited soluble comonomer, whereby the sum of (a) and (b) constitutes at least 90% by weight of the polymer and the remaining part of the copolymer can

be made up of water-soluble comonomers. These emulsion polymers are available in the form of an aqueous dispersion and are used as thickeners for aqueous systems whose pH value is below 7.

To the extent that polymers containing water-soluble dialkylaminoalkyl(meth)acrylate groups are used as flocculating agents, the activity of these products decreases rather quickly when they are in the form of an aqueous solution. After longer storage, these products are practically inactive anti-fouling agents.

The task of the invention is therefore to provide water-soluble polymers which, when used as paper aids, provide improved retention, dewatering speed and flocculation effect compared to the known copolymers of acrylamide, and which are at the same time effective flocculation agents for waste water and sludge.

The task is solved according to the invention with water-soluble

homopolymers of neutralized or quaternized di-C^-

to C 1 -alkylaminoneopentyl (meth)acrylates and copolymers,

which contains at least 5% by weight of di-C3- to C3-alkylaminoneopentyl-(meth)acrylate polymerized in neutralized or quaternized form and has a K-value of 150-300. These copolymers are added to the paper stock during the production of paper and, in contrast to comparable known polymers, cause an unexpected increase in the retention, dewatering rate and fluffing rate. Aqueous solutions of the copolymers according to the invention, which are used as flocculants for waste water and sludge, can be stored for a longer period of time without any significant drop in the effectiveness of the flocculant.

The homo- and copolymers can be prepared by known methods

methods by polymerization of the monomers, e.g. by polymerization in a water-in-oil emulsion according to the method known from BRD patent 10 89 173 or according to the method with inverse suspension polymerization according to BRD patent 10 81 228, as well as by solution polymerization in water and also by precipitation polymerization in inert organic solvents. In all methods, the polymerization initiators that are common for this are used, e.g. peroxides, redox catalysts or azo-bis-isobutyronitrile. For the production of homopolymers, neutralized or quaternized di-C₁- to C₁-alkylaminoneopentyl(meth)acrylates (monomers group (a)) are polymerized in the absence of other monomers. Copolymers of di-C^- to C^-alkylaminoneopentyl acrylates resp. of di-C-3- to C3-alkylaminoneopentyl methacrylates containing at least 5% by weight of these monomers polymerized. Preferably, copolymers are produced which contain 20-80% by weight di-C^-

to C₁-alkylaminoneopentyl acrylate or di-C₁- to C₁-alkylaminoneopentyl methacrylate polymerized. C 1 to C 4 alkyl groups are methyl, ethyl, n-propyl and isopropyl groups.

Comonomers of group (b) preferably include acrylamide, methacrylamide and esters of amino alcohols of acrylic acid and methacrylic acid, e.g. dimethylaminoethyl acrylate, diethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminopropyl acrylate, diethylaminopropyl methacrylate and dimethylaminobutyl acrylate in consideration. The esters of the amino alcohols of acrylic acid resp. Methacrylic acid and also the di-C₁- to C₁-alkylaminoneopentyl(meth)acrylates are always subjected to polymerization in neutralized or quaternized form. Suitable quaternizing agents are, for example, alkyl halides, such as methyl chloride, ethyl chloride, methyl bromide, ethyl bromide, methyl iodide, propyl chloride and butyl chloride, dimethyl sulfate, diethyl sulfate, lauryl chloride, alkylene oxides, such as ethylene oxide and propylene oxide, hydroxyalkyl halides, epihalohydrins, e.g. epichlorohydrin and epibromohydrin, as well as benzyl chloride.

Inorganic and organic acids that form salts with the basic monomers are suitable for neutralization, e.g. sulfuric acid, hydrochloric acid, phosphoric acid, acetic acid, formic acid and adipic acid.

Further comonomers of group (b) are ethylenically unsaturated carboxylic acids with 3-5 carbon atoms, such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, fumaric acid and maleic anhydride as well as acidic monomers, such as alkali or ammonium salts of vinyl benzyl sulphonates, acrylamidopropane sulphonic acid and vinyl sulphonic acid.

For modification, the copolymers can contain monomers of group (c) up to approx. 20% by weight polymerized, whereby the sum of the weight percentages (a), (b) and (c) always amounts to 100. Monomers of this group are acrylic acid and methacrylic acid esters of monohydric alcohols containing 1-12 carbon atoms, acrylonitrile, methacrylonitrile, vinyl ester, f .ex. vinyl acetate, vinyl propionate and vinyl butyrate, diisobutylene and styrene.

Of particular importance for use in the paper industry are the homopolymers of dimethylaminoneopentyl acrylate as well as copolymers containing 20-80% by weight dimethylaminoneopentyl acrylate and 80-20% by weight acrylamide, methacrylamide, dialkyl-aminoalkyl esters of acrylic acid or Methacrylic acid polymerized. Acrylamide and methacrylamide can be replaced in the copolymers in whole or in part with the aforementioned basic acrylates, e.g. diethylaminoethyl acrylate.

Copolymers containing 20-95% by weight di-C-^- to C-,-alkylamino neopentyl acrylate in neutralized and quaternized form and which comonomer 5-80% by weight of ethylenically unsaturated amides are preferably used as flocculants for waste water and sludge

C^- to C1- carboxylic acids, di-C-^- to C^-alkylamino-C2 to C^-alkyl esters of acrylic acid or methacrylic acid and/or di-C^- to C-j-alkylamino-C^ to C^- alkylene (meth) acrylamides polymerized. Comonomers of this type are, for example, acrylamide, methacrylamide and esters of amino alcohols of acrylic acid and methacrylic acid, e.g. dimethylaminoethyl acrylate, diethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, diethylaminopropyl acrylate, diethylaminopropyl methacrylate and dimethylaminobutyl acrylate. Examples of dialkylamino-alkylene (meth)acrylamides are compounds of formula

Compounds of this type are, for example, N,N-dimethylaminopropylacrylamide, N,N-dimethylaminopropylmethacrylamide and N,N-diethylaminobutylacrylamide.

The polymerization temperature depends on the polymerization initiator used in each case. It can fluctuate within a wide range, for example between 0 and 120°C. As a rule, polymerisation is carried out at normal pressure and temperatures of 20-80°C, whereby a good thorough mixing of the components is ensured. The monomers are practically completely polymerised. In connection with the main polymerization, a post-polymerization can be carried out, in order to reduce the residual monomer content in the polymer as far as possible.

The molecular weights of the polymers are preferably more than 1 million. For further characterization of the polymers, the K value according to Fikentscher serves. The K-values amount to 150-300 and are preferably in the range 170-250. In particular, the high molecular weight polymers are suitable as retention, dewatering and fluffing agents in the production of paper.

For this purpose, 0.005-0.5, preferably 0.01-0.1, is added to the paper stock, calculated on dry fibres. % by weight of one of the copolymers containing di-C 1 - to C 4 -alkylamino-neopentyl (meth)acrylate. The di-C^- to C^-aminoneopentyl(meth)-acrylates unfold their activity in the weakly alkaline, neutral and acidic material. They can be used for wood-free as well as wood-containing substances. They are particularly effective as retention agents for chalk and kaolin.

The high molecular weight water-soluble homo- and copolymers are also used as flocculants for waste water and sludge. In this connection, the waste water can come from municipal sewage treatment plants or industrial sewage treatment plants. In this case, the homo- and copolymers serve to clarify the waste water. However, they can equally well be used for the treatment of sludge from municipal sewage treatment plants and activated sludge from industrial wastewater treatment plants. Flocking agent is used in an amount of 100-350 g/m 3 sludge. When clarifying waste water, 1-20 g of flocculant per m 3 of waste water is used. In contrast to the traditional cationic flocculation agents, one achieves with the homo- or copolymers that are used according to the invention, and which contain di-C-^- to C^-alkylaminoneopentyl (meth) acrylate in neutralized or quaternized form polymerized, an increase in the flocking effect, which manifests itself in achieving maximum flocking at low use of the fluffing agent. Aqueous solutions of polymers containing dialkylaminoneopentyl (meth)acrylate retain, in contrast to aqueous solutions of known cationic polymers, their activity as flocculants, i.e. the stability of the activity of the aqueous polymer solutions is good, so that polymer solutions that have been prepared do not immediately must be consumed, but will be able to be stored for a longer period of time before use as a flaking agent.

The parts given in the examples are parts by weight, the percentages given are calculated on the weight of the substances. The K values of the polymers were measured according to H. Fikentscher, Cellulose Chemie 13, 58-64 and 71-74 (1932) in 5% aqueous sodium chloride solution at a temperature of 25°C; K = k . 10 .

Preparation of the polymers

I. Production of water-in-oil polymer emulsions

General regulation

In a container equipped with a stirrer, thermometer and nitrogen inlet and outlet, the following components are mixed: 220 parts of a mixture of 84% saturated aliphatic hydrocarbons and 16% naphthenic hydrocarbons (boiling range 192-254°C), 35 parts of the reaction product of 1 mol oleyl glycidyl ether, 1 mol glycerol and 2 mol ethylene oxide and

6 parts of an addition product of 10 moles of ethylene oxide

and 1 mole of nonylphenol.

Into this mixture is stirred the aqueous monomer phase whose relevant composition is given in table 1. Nitrogen is passed through the emulsion for 30 minutes and then heated to 60°C over 15 minutes. At this temperature, a solution of 0.15 parts of 2,2'-azo-bis-isobutyronitrile in a little acetone is added. The temperature of the reaction mixture is maintained for 2 hours in the range 60-65°C. The same amount of the polymerization initiator is then added once more, and post-polymerization is carried out for 2 hours at 65°C. You get a coagulant-free and sedimentation-stable water-in-oil polymer emulsion.

From the thus obtained water-in-oil polymer emulsions, aqueous polymer solutions were prepared by the method specified in US patent 3,624,019, whereby 2% of nonylphenol which had been reacted with ethylene oxide in a molar ratio of 10:1 was added to the emulsions, and diluted with water to a polymer content of 0.25%.

II. Powdered copolymers

Polymer II/l is a commercially available powdered copolymer of 60% acrylamide and 40% diethylaminoethyl acrylate sulfate with a K-value of 195.

Polymerizate II/2 was prepared in the following way:

114 g of dimethylaminoneopentyl acrylate sulfate, 170 g of acrylamide and 1 g of formic acid in 280 g of water were adjusted to pH 3 with sulfuric acid and 0.57 g of 2,2<1->azo-bis(N,N'-dimethylisobutyr-amidine)dihydrochloride was added. The solution was introduced at 60°C into a medium consisting of 1.6 1 cyclohexane and 5.5 g of protective colloid A according to BRD-off.skrift 27 10 372, within 1 hour. (Protective colloid A was obtained as a residue by reaction of dicyclopentadiene, maleic anhydride and styrene 1 autoclave at 267°C after relief and distillation of the volatile components.) After 1 more hour at 60°C and azeotropic removal of the water, a polymerizate with K is obtained -value 206

(0.1% in 5% aqueous saline solution).

III. Production of water-in-oil polymer emulsions

(general regulations)

In a container equipped with stirrers, a thermometer and a nitrogen inlet and outlet, the components of the oil phase whose composition is given in table 2 are mixed. in this mixture the aqueous monomer phase is stirred (composition, see also table 2). Nitrogen is passed through the emulsion for 30 minutes and then heated to a temperature of 60°C within 15 minutes. At this temperature, a solution of the starter in a little acetone (type and quantity, see table 2) . The temperature of the mixture is maintained for 2 hours in the range of 60-65°C. The same amount of the polymerization initiator is then added once more, and the reaction mixture is then<p>polymerized for 2 hours at 65°C. You get a coagulant-free and sedimentation-stable water-in-oil polymer emulsion.

In order to investigate the activity of the polymers described above, aqueous polymer solutions were prepared from the water-in-oil polymer emulsions by the method specified in US patent 3,624,019. For this purpose, the emulsions were stirred into water which, calculated on the polymer emulsion, contained 2% of a nonylphenol reacted with 10 mol of ethylene oxide. So much water was then added that the polymer content was 0.1%. These 0.1% aqueous polymer solutions were used in examples 9 and 10.

Application of the polymers

Example 1

The activity of the polymerizate 1/7 as a paper aid was tested using the grinding degree test according to Schopper-Riegler and the dewatering time in relation to the polymerizate I/l according to the state of the art.

In the grinding degree test according to Schopper-Riegler, a woody and kaolin-containing newsprint with a pH value of 4.8 and an alum content of 1.5% was used. The material density was 0.2%, the kaolin content approx. 12%. The dewatering time was determined by determining the time required for 700 ml of the above described substance to pass the Schopper-Riegler instrument. The dewatering time for the aid-free paper stock was 97 sec., the painting degree 59°SR. These determinations were also carried out using this substance model with different addition quantities of the polymers I/1 and 1/7. The amounts of the polymers used and the results obtained are summarized in table 4.

Example 2

With the aid of a Rapid-Kothen sheet former, paper sheets with a basis weight of approx. 70 g/m 2. For the aid-free paper stock, the chalk content in the paper was 3.2%. The chalk content of the paper was determined in each case by ashing the paper sheets. The activity of the polymerizate 1/7 as a retention agent was compared with the value for the known retention agent polymerizate I/l. The quantities of the polymers used, calculated on dry paper stock, as well as the results obtained, are summarized in table 5.

Example 3

The dewatering rate of polymers listed in Table 1 was tested on a fabric model using a Schopper-Riegler instrument. Wood-containing newsprint material with a pH value of 4.8 and containing 1.5% alum and approx. 12% kaolin. If no aid was added to the substance, the dewatering time was 95.1 sec. The dewatering times for the polymers described in table 1 at different amounts used, calculated on dry matter, are given in table 6.

Example 4

On an experimental paper machine with a sieve width of 80 cm, it was at a constant speed of 80 m/min. manufactured paper with a basis weight of approx. 85 g/m<2>' of a wood-free substance which was composed of 60 parts sulphate cellulose of pine, 40 parts sulphate cellulose of birch and 50 parts chalk, without the use of a retention agent. Next, the effect of the polymers I/l and 1/7 was tested. The results are compiled in table 7.

Example 5

With the help of the regulation for determining the dewatering time stated in example 1, the dewatering-accelerating effect of the powdered polymers II/1 (comparison) and II/2 (according to the invention) was measured on a wood-containing neutral newsprint. The material density was 0.2%. Without the use of a dewatering aid, a dewatering time of 115 seconds was obtained for this fabric model. When using the quantities of polymers II/1 and II/7 indicated in Table 8, the following dewatering times were measured:

Example 6

Example 5 was carried out with a wood-containing newsprint whose pH value was 4.5 and which contained 1.5% alum. The material density was 0.2%. Without the use of a dewatering aid, the dewatering time was 10 5.3 sec. The dewatering times for the polymers II/1 and II/2 are given in table 9.

Example 7

Using a Rapid-Kothen sheet former, sheets were formed from a paper stock consisting of 80% bleached sulphite cellulose and 20% kaolin with a pH value of 4.8 and an alum content in the paper stock of 1.5% with a basis weight of about. 6 5 g/m 2. The ash content of the paper sheets in the absence of a retention agent amounted to 5.3%. When using the polymers II/1 according to the state of the art and II/2 according to the invention, the ash content values indicated in Table 10 were found.

Example 8

To determine the flocking effect of the polymers

became a paper material rich in fines, which per liter contained 1 g of sulphite cellulose and 0.25 g of kaolin, with different amounts of polymers II/1 and II/2 added. After stirring and depositing the suspension, the transparency of the overlying clear water was determined photometrically in each case. The results

is summarized in the table.

Test methods

a) Determination of the flock number

750 ml of a waste water or a sludge remained in a 1-litre

measuring cylinder to which specific quantities of a 0.1% aqueous flocculant solution have been added. The flogging occurs practically instantly. The contents of the measuring cylinder are then emptied into a Biichner funnel and filtered. On the basis of the filter, the fuzzing is judged visually. Here means:

Fuzzing number 1 = barely visible fuzzing

Fooking number 2 = little fooking

Flocking number 3 = medium flocking

Plucking number 4 = good plucking, mostly sufficient

for practice

Shedding number 5 = very good, optimal shedding

Example 8

To determine the flocking effect of the<p>olymerizates

became a paper material rich in fines, which per liter contained 1 g of sulphite cellulose and 0.25 g of kaolin, with different amounts of polymers II/1 and II/2 added. After stirring and depositing the suspension, the transparency of the overlying clear water was determined photometrically in each case. The results are summarized in the table.

Test methods

a) Determination of the flock number

750 ml of a waste water or a sludge remained in a 1-litre

measuring cylinder to which specific quantities of a 0.1% aqueous flocculant solution have been added. The flogging occurs practically instantly. The contents of the measuring cylinder are then emptied into a Biichner funnel and filtered. On the basis of the filter, the fuzzing is judged visually. Here means:

Fuzzing number 1 = barely visible fuzzing

Fooking number 2 = little fooking

Flocking number 3 = medium flocking

Plucking number 4 = good plucking, mostly sufficient

for practice

Shedding number 5 = very good, optimal shedding

b) Scavenging activities

This test determines - likewise in a 1-litre measuring cylinder - the quantity of flocculant that must be added to a waste water or sludge in order to achieve optimal flocculation (flocculation number = 5) .

Example 9

On an anaerobic sludge from a municipal sewage treatment plant, the flocculation efficiency for polymerisate III/l and polymerisate III/A (comparison) was determined by the method indicated above under b). For polymerizate III/l, the optimal quantity for a flocculation was 250 mg/l sludge, while for polymerizate III/A

350 mg/l sludge had to be used. According to this, polymerizate III/l is significantly more effective than polymerizate III/A according to the state of the art.

Example 10

0.1% aqueous solutions of polymerizate III/2 and polymerizate III/B were stored at a temperature of 23°C for up to 24 hours. After specific times indicated in Table 12, the flocking number for the aqueous polymer solutions was determined. The results are compiled in table 12. The flocculation rate was determined using an anaerobic sludge from a municipal sewage treatment plant.

From the table it appears that the aqueous solution of the polymer III/2 to be used according to the invention is significantly more stable than the solution of the known fluffing agent polymer III/B.

Claims (5)

1. Process for the production of water-soluble basic (meth)acrylates, characterized by polymerizing neutralized or quaternized di-C^ - to C^ -aminoneopentyl (meth)acrylates optionally in a mixture with up to 95% by weight, calculated on the mixture, of other water-soluble, ethylenically unsaturated monomers copolymerizable with the former, using polymerization initiators. 2. Method as stated in claim 1, characterized in that during the polymerization a mixture of a) 20-95% by weight di-C 1 - to C 2 -alkylaminoneopentyl-(meth)-acrylate in neutralized or quaternized form, and as water-soluble comonomers b) 5-80% by weight amides of ethylenically unsaturated C^ - to C^ -carboxylic acids, di-C^ - to C-j-alkylamino-C^- to C^ -alkyl esters of acrylic acid or methacrylic acid or di-C-^ - to C₁ -alkylamino-C₂ - to C₂ -alkylene(meth)acrylamides or ethylenically unsaturated C₂ to C₂ mono- and dicarboxylic acids, maleic anhydride, vinylsulfonic acid, vinylbenzylsulfonic acid, acrylamidopropanesulfonic acid as well as the alkali or ammonium salts of the aforementioned carboxylic acids . 3. Process as stated in claims 1 and 2, characterized in that the monomer mixture used in the polymerization also contains up to 20% by weight of acrylic acid or methacrylic acid esters of monovalent C-^ to C^2~ as a monomer from group (c) alcohols, acrylonitrile, methacrylonitrile, vinyl esters of saturated C2~ to C3 -carboxylic acids, diisobutylene and styrene. 4. Application of the homo- and copolymers according to claims 1-3, as retention, dewatering and fluffing agents in the manufacture of paper. 5. Use of the homo- and copolymers as stated in claims 1-3, as flocculants for waste water and sludge.