FR2683533A1 - Water-soluble polymers and/or copolymers with increased biodegradability and their applications - Google Patents

Abstract

Acrylic and/or vinyl polymers and/or copolymers containing acidic groups in which 60% to 90% of the active acidic sites are neutralised with the magnesium ion, with a specific viscosity not exceeding 25 and with increased biodegradability, that is whose degradation after 36 days is higher than 50% according to the modified Sturm method. Application of these polymers to fields as diverse as paper, paints, plastics, petroleum, drilling fluids, water treatment, detergents, cosmetics, textiles, inks, leather, grinding and/or breaking up of minerals in water.

Description

BIODEGRADABLE HYDROSOLUBBLE POLYMERS AND / OR COPOLYMERS
INCREASED AND THEIR APPLICATIONS.

The present invention relates to a water-soluble, biodegradable acrylic and / or vinyl polymer and / or copolymer used in fields as diverse as the paper industry, paints, plastics, petroleum, drilling fluids, water treatment and the like. water, detergents or cosmetics, textiles, inks, leather, grinding and / or disintegrating minerals in water or others.

In all these fields of activity, the problem of safeguarding the environment is becoming more and more urgent to solve.

Thus, for ecological reasons, those skilled in the art must use compounds whose biodegradability is increased.

For this purpose, it already knows biodegradable polymers whose biodegradability results from a grafting of polyalkylene oxide on acidic monomers such as acrylic acid (EP 0429307 and EP 0430574), or the presence of maleic anhydride with well-defined polymerization conditions (EP 0396303), or the termination of the polyacrylate chain by hydroxy or sulfide groups (US 4095035), or else by their monomeric composition (US 4897458 and EP 0291808).

Thus, the object of the invention is to provide an acrylic and / or vinyl polymer and / or copolymer of increased biodegradability, that is to say the degradation of which after 36 days is greater than 50% according to the method of Sturm modified, in order to best correspond to environmental protection regulations (Official Journal of the EC

 nos251).

Another object of the invention is to provide an acrylic and / or vinyl polymer and / or copolymer of increased biodegradability, of specific viscosity at most equal to 25, and preferably at most equal to 10.

Surprisingly, the Applicant has found that the object of the invention is obtained when 60 to 90% of the active acid sites of the polymer and / or acrylic and / or vinyl copolymer is neutralized by the magnesium ion.

These acrylic and / or vinyl polymers and / or copolymers are obtained according to known methods of radical polymerization, in the presence of polymerization regulators such as, for example, organic compounds based on hydroxylamine and in the presence of polymerization initiators. such as peroxides and persalts, for example hydrogen peroxide, persulfate, sodium hypophosphite, hypophosphorous acid, at least one of the following monomers and / or comonomers: acrylic and / or methacrylic acid, itaconic, crotonic, fumaric, maleic anhydride, or isocrotonic, aconitic, mesaconic, sinapic, undecylenic, angelic, canellic, hydroxyacrylic acid, acidic or partially neutralized form, acrolein, acrylamide, acrylonitrile, esters of acids acrylic and methacrylic, and in particular dimethylaminoethyl methacrylate, vinylpyrrolidone, vinylcaprolactam, ethylene, propylene, isobuty ethylene oxide, diisobutylene, vinyl acetate, styrene, alpha-methyl styrene, methyl vinyl ketone, in a polymerization medium which may be water, methanol, ethanol, propanol, isopropanol, butanols, or their mixtures, or else dimethylformamide, dimethylsulfoxide, tetrahydrofuran, acetone, methyl ethyl ketone, ethyl acetate, butyl acetate, hexane, heptane, benzene, toluene, xylene, mercaptoethanol, tert-dodecyl mercaptan, thioglycolic acid and its esters, n-dodecyl mercaptan, acetic acid, tartaric acid, lactic acid, citric acid, gluconic acid, glucoheptonic acid, 2-mercaptopropionic acid, thiodiethanol, halogenated solvents such as carbon tetrachloride, chloroform, methylene chloride, monopropylene glycol ethers, diethylene glycol or their mixture.

The solution of the acidic polymerisate obtained is then partially or totally neutralized in a proportion of 60% to 90% of a neutralization agent containing the magnesium ion, and optionally of a neutralization agent containing a monovalent ion.

The monovalent neutralizing agent is selected from the group consisting of alkaline cations (such as sodium, lithium and potassium), ammonium, aliphatic and / or cyclic primary, secondary or tertiary amines (such as for example, ethanolamines (mono, di, tri-ethanolamine), mono and diethylamine, cyclohexylamine, methylcyclohexylamine).

The solution of the acid polymer or else neutralized can also be treated according to static or dynamic processes known to those skilled in the art by one or more polar solvents belonging in particular to the group consisting of methanol, ethanol, propanol isopropanol, butanols, acetone, tetrahydrofuran, thus producing a two-phase separation, each recovered separately.

The least dense phase comprises the major fraction of the polar solvent and constitutes the low molecular weight polymer and / or copolymer fraction, whereas the denser aqueous phase constitutes the fraction of higher molecular weight polymers and / or copolymers.

The polymers and / or copolymers according to the invention generally have a specific viscosity of at most 25, and preferably at most 10.

et est déterminée de la
On prend une solution du polymérisat de façon à obtenir une solution correspondant à 2,5 g de polymère sec et à 50 ml d'une solution de chlorure de sodium à 60 g/l.This specific viscosity of the polymers and / or copolymers is symbolized by the following letter.

and is determined from the
A solution of the polymer is prepared so as to obtain a solution corresponding to 2.5 g of dry polymer and to 50 ml of a 60 g / l sodium chloride solution.

Then, measured with a capillary viscosimeter of Baume constant equal to 0.000105 placed in a thermostatically controlled bath at 250C the flow time of a given volume of the aforementioned solution containing the polymer and / or copolymer, as well as the time flow of the same volume of aqueous sodium chloride solution without said polymer and / or copolymer.

It is then possible to define the viscosity "5" thanks to the following relation
(flow time of (flow time of
the polymer solution) - the NaCl solution
# =
flow time of the NaCl solution
The capillary tube is generally chosen such that the flow time of the NaCl solution, free from polymer and / or copolymer, is from about 90 to 100 seconds, thus giving very good specific viscosity measurements. precision.

These acrylic and / or vinyl polymers and / or copolymers according to the invention can also be treated by any known means to isolate them in the form of a fine powder.

In practice, the measurement of biodegradability is carried out using the modified Sturm test, described in the Journal
Official of the European Community nos251 of 19.09.1984 ,. and in the OECD Guidelines (Organization of
Economic Cooperation and Development) n0301B of 12.05.1981. This biodegradability, expressed as a percentage, is actually the amount of CO2 produced over a 36-day period that this substance is capable of producing, calculated on the basis of its carbon content. Before proceeding with these measurements, it is necessary to prepare the various constituents of the test, which are - a solution of barium hydroxide (Ba (OH) 2 - 8H2O), in order to trap and titrate the amount of CO2 produced during the duration of the test, - an inoculum used to inoculate microorganisms from activated sludge and controlled by reference substance, in this case a solution of sodium acetate at 20 mg / l, - the sample of the substance to be tested and the medium for the test.

Indeed, this medium consists of solutions of various reagents, so-called stock solutions, obtained from high quality water, that is to say distilled water containing no toxic substance (especially copper), with a low carbon content (0.5 mg TOC / l) (TOC = Total Organic Carbon) and a resistivity greater than or equal to 18 ML / cm, and is composed per liter of high quality water of - 4 ml d a solution of ferric chloride obtained by dissolving 0.25 g of FeCl 3 - 6H 2 O in one liter of high quality water, - 1 ml of a solution of magnesium sulphate obtained by dissolving 22.50 g of MgSO 4 - 7H2O in a liter of high quality water, - 1 ml of a solution of calcium chloride obtained by dissolving 27.50 g of anhydrous CaCl 2 in one liter of high quality water, - 2 ml of a solution of phosphate buffer obtained by dissolving 8.50 g of potassium dihydrogenphosphate (KH2PO4), 21.75 g of dipotassium hydrogenphosphate (K2HPO4), 3 3.40 g of dissodium hydrogen phosphate dihydrate (Na2HPO4 - 2H2O) and 1.70 g of ammonium chloride (NH4Cl) in one liter of high quality water, - 1 ml of ammonium sulphate solution obtained by dissolving 40 g of (NH4) 2 SO4 in one liter of high quality water.

These dissolutions being carried out for 3 liters of reaction medium, it is necessary to prepare the inoculum.

The inoculum used comes from activated sludge, freshly collected from a sewage treatment plant in good working order. This station must not treat industrial effluents, except in negligible quantities (approximately 10%).

Upon arrival at the laboratory, the activated sludge is aerated for four hours, then 500 ml of the suspension is taken and homogenized for two minutes at medium speed using a magnetic stirrer before decanting for 1/2 hour.

If the supernatant still contains a significant amount of sludge solids after 30 minutes, either allow it to settle further for 30 to 60 minutes, or treat it for better settling.

 It is necessary to allow the supernatant to settle so that sufficient volume is available to inoculate a 1% inoculum per CO2 determination flask, and to avoid entraining solid particles of sludge that could distort the measurement. CO2 production.

 There is no need to count in the supernatant fraction to determine the number of microorganisms.

The inoculum should normally contain from 106 to 20 x 106 units or colonies per ml. It must be used the day of its preparation.

All this done, it is sufficient to introduce into 3 different bottles a control without substance to study, a concentration of substance to study (10 mg / l) and a reference (sodium acetate) whose biodegradability must be greater than 60%, 2470 ml of high-quality water, as well as each stock solution in an amount corresponding to 3 liters of high quality water and 30 ml of inoculum, then aerate the mixture by bubbling air free of CO2 (after passing in a bath of barium hydroxide) for 24 hours before the start of the test.

The barium hydroxide solution is passed on filter paper and kept out of the air to prevent any absorption of CO2.

The test begins after 24 hours of bubbling by introducing into each of the bottles containing the aerated mixture - of the analyte at a concentration of 10 mg / l - the reference substance at a concentration of 20 mg / l - nothing to constitute a white.

The CO2 produced in each cylinder reacts with the barium hydroxide; the quantity of CO2 produced is determined by titration of the remaining Ba (OH) 2 by means of 0.05 N HCL. For this purpose, the CO2 absorber flask closest to the reactor is disconnected periodically (every two or three days). carboy.

After removing the bottles closest to the bottles, the Ba (OH) 2 solution is titrated with 0.05 N HCl using phenolphthalein as indicator.

The two remaining absorbent vials are then brought closer to the bottle by shifting them each by one place, and after each assay at the end of the series, a new absorbent bottle containing 100 ml of a fresh solution of Ba (OH) 2 at 0.025 N is added. Titrations are carried out when necessary (before the appearance of a BaCO3 precipitate in the second trap after that of 8 N concentrated NaOH), approximately every other day for the first ten days, then every five days. days until the 36th day. Stopping the experiment is a function of the appearance of the plateau, reflecting the degradation of the substance to be studied.

On the 35th day, the pH of the solutions contained in the bottles is measured again, and 1 ml of concentrated HCl is added to each bottle in order to remove the inorganic carbonate. The bottles are aerated overnight and samples are taken from each of them to determine the dissolved organic carbon (DOC), which is only for information purposes over the entire period elapsed, and is carried out titration on the 36th day.

The scope and interest of the invention will be better understood by the following examples.

Example 1
This example relates to the biodegradability measurement of the same polyacrylic acid neutralized with different ions.

Test No. 1 illustrating the prior art indicates the biodegradability of sodium polyacrylate neutralized to 100% with sodium and specific viscosity 0.54.

Test No. 2 illustrating the invention indicates the biodegradability of a mixed polyacrylate of sodium and magnesium obtained by total neutralization so that 25% of the active acid sites are neutralized by sodium and 75% by magnesium and specific viscosity 0.54.

For all these tests, the source of micro-organisms comes from activated sludge taken from the wastewater treatment plant.
Pierre Bénite (France), and the operating conditions are those mentioned above.

All results are shown in Table 1.

TABLE 1

<SEP> TEST <SEP> Neutralization <SEP> Number <SEP> Biodegradability
<tb><SEP> No. <SEP><SEP> SEP Rate <SEP> SEP Groups><SEP>SEP>%<SEP> Groups
<tb><SEP><SEP> neutralized <SEP> neutralizing <SEP> days
<tb> Art
<tb> anterus <SEP> 1 <SEP> 100 <SEP> Na <SEP> 36 <SEP> 43
<tb> Invention <SEP> 2 <SEP> 25/75 <SEP> Na / Mg <SEP> 36 <SEP> 65
<Tb>
Reading Table 1 shows the difference in biodegradability between the polymer of the prior art and that according to the invention.

In fact, for test No. 1, the percentage of the theoretical amount of CO 2 is 43% after 36 days, whereas that of test No. 2 is 65% after 36 days.

Thus, only the polymer according to the invention obtained by the neutralization of a polyacrylic acid by means of a neutralizing mixture containing the magnesium ion gives a biodegradability greater than 50% after 36 days of test.

Example 2
This example concerns the biodegradability measurement of the same starting polyacrylic acid with a specific viscosity of 0.54, neutralized with magnesium levels of up to 88% of the active acid sites of the polymer.

Test n03 measures the biodegradability of a mixed polyacrylate of sodium and magnesium neutralized so that 35% of the active acid sites are neutralized by sodium and 65% by magnesium.

Test n04 measures the biodegradability of a mixed polyacrylate of sodium and magnesium neutralized so that 25% of the active acid sites are neutralized by sodium and 75% by magnesium.

Test No. 5 measures the biodegradability of a mixed polyacrylate of sodium and magnesium neutralized so that 12% of the active acid sites are neutralized by sodium and 88% by magnesium.

Test n06 measures the biodegradability of a polyacrylate of the same specific viscosity 0.54, of which 75% of the active acid sites are neutralized by the magnesium ion.

The source of microorganisms and the operating conditions of the test are identical to those of Example 1.

All results are reported in Table 2.

TABLE 2

TESTING <SEP> Neutralization <SEP> Number <SEP> Biodegradability
<tb> No. <SEP><SEP> SEP Rate <SEP> SEP Groups <SEP>% <SEP> Groups
<tb><SEP><SEP> neutralized <SEP> neutralizing <SEP> days
<tb> 3 <SEP> 35/65 <SEP> Na / Mg <SEP> 36 <SEP> 57
<tb> 4 <SEP> 25/75 <SEP> Na / Mg <SEP> 36 <SEP> 65
<tb> 5 <SEP> 12/88 <SEP> Na / Mg <SEP> 36 <SEP> 71
<tb> 6 <SEP> 75 <SEP> Mg <SEP> 36 <SEP> 63
<Tb>
Reading the results recorded in Table 2 shows that, for all tests n03 to n06, the percentage of the theoretical amount of CO2 is greater than 50% after 36 days of testing.

Thus, a degree of neutralization by the Mg ion ranging from 60 to 90% of the active acid sites makes it possible to obtain a polymer according to the invention having an improved biodegradability, greater than 50% after 36 days of testing, and best results are obtained for a polymer according to the invention, 75% of the active acid sites are neutralized by the magnesium ion, and 25% by the sodium ion, and better still when 88% of the active acid sites are neutralized by the magnesium ion and 12% by the sodium ion.

Example 3
This example relates to the measurement of the biodegradability of polyacrylic acids of different molecular weights and all fully neutralized so that 75% of the active acid sites are neutralized by the magnesium ion and 25% by the sodium ion.

Test n07 measures the biodegradability of a polyacrylate of specific viscosity 0.3.

Test No. 8 is identical to test No. 2 (specific viscosity 0.54).

Test No. 9 measures the biodegradability of a polyacrylate of specific viscosity 5.0.

The source of microorganisms and the operating conditions of the test are identical to those of Example 1.

All results are shown in Table 3.

TABLE 3

<tb> TEST <SEP> Viscosity <SEP> Number <SEP> Biodegradability <SEP>
<tb><SEP> of
<tb><SEP> No. <SEP> Specific <SEP> days <SEP>
<tb><SEP> 7 <SEP> 0.30 <SEP> 36 <SEP> 77
<tb><SEP> .8 <SEP> 0.54 <SEP> 36 <SEP> 65
<tb><SEP> 9 <SEP> 5.0 <SEP> 36 <SEP> 59
<Tb>
Reading the results recorded in Table 3 shows that, whatever the specific viscosity, that is to say the molecular weight of the polymer, the polymers according to the invention partially neutralized by the magnesium ion have a improved biodegradability, greater than 50% after 36 days of test.

Example 4
This example relates to the measurement of the biodegradability of other polymers neutralized or not by the magnesium ion.

Test n010 measures the biodegradability of a polymer obtained by polymerization and grafting of acrylic acid on polyethylene glycol of molecular weight 3400 and neutralized to 100% by sodium, as described in example 1 of the patent
EP0429307.

Test n011 measures the biodegradability of the same polymer as that of test ne10, but neutralized to 100% by a mixture corresponding to a neutralization of 25% sodium and 75% magnesium.

The source of microorganisms and the operating conditions of the test are identical to those of Example 1.

All results are shown in Table 4.

TABLE 4

<SEP> TEST <SEP> Neutralization <SEP> Number <SEP> Biodegradability
<tb><SEP> No. <SEP><SEP> SEP Rate <SEP> SEP Groups><SEP>SEP>%<SEP> Groups
<tb><SEP><SEP> neutralized <SEP> neutralizing <SEP> days
<tb> Art
<tb> previous <SEP> 10 <SEP> 100 <SEP> Na <SEP> 36 <SEP> 48
<tb> Invention <SEP> 11 <SEP> 25/75 <SEP> Na / Mg <SEP> 36 <SEP> 68
<Tb>
Reading the results recorded in Table 4 shows the difference in biodegradability between the polymer of the prior art and that according to the invention.

Indeed, for the test ne10, the biodegradability is 48% after 36 days of test, whereas that of the test n011 is 68% after 36 days of test.

Thus, only the polymer according to the invention, 75% of which active acid sites are neutralized with magnesium, gives improved biodegradability, greater than 50% after 36 days of test.

Claims (8)

1) water-soluble, biodegradable acrylic and / or vinyl polymer and / or copolymer, resulting either from the polymerization and / or copolymerization of acrylic and / or vinyl monomers, or from the treatment with one or more polar solvents according to static or dynamic processes of acrylic and / or vinyl polymers and / or copolymers, ie grafting of acrylic and / or vinyl monomers on substrates based on polyalkylene glycol, characterized in that the active acid sites of said polymer and / or copolymer are totally or partially neutralized by at least one neutralization agent containing the magnesium ion, such that the percentage of neutralization of the active acid sites by the magnesium ion varies between 60% and 90% and, in addition, possibly by at least one neutralization agent having a monovalent ion which can neutralize up to 40% of the active acid sites, and in that the biodegradability is greater than 50% 36 days after the modified Sturm test. 2) a biodegradable water-soluble acrylic and / or vinyl polymer and / or copolymer according to claim 1, characterized in that the monovalent ion of the neutralization agent is chosen from sodium, potassium, lithium or ammonium ions or amines primary, secondary or tertiary aliphatic and / or cyclic. 3) a biodegradable hydrosoluble acrylic and / or vinyl polymer and / or copolymer according to claim 1, characterized in that 75% of the active acid sites of said polymer and / or copolymer are neutralized with a neutralization agent containing the magnesium ion and 25% by a neutralizing agent containing the sodium ion. 4) a biodegradable water-soluble acrylic and / or vinyl polymer and / or copolymer according to claim 1, characterized in that 88% of the active acid sites of said polymer and / or copolymer are neutralized with a neutralization agent containing the magnesium ion and 12% by a neutralizing agent containing the sodium ion. 5) biodegradable water-soluble acrylic and / or vinyl polymer and / or copolymer according to any one of claims 1 to 4, characterized in that it has a specific viscosity of at most 25, and preferably at most equal to 10. 6) water-soluble acrylic and / or vinyl polymer and / or biodegradable copolymer according to claim 5, characterized in that it is a solution. 7) water-soluble acrylic and / or vinyl polymer and / or biodegradable copolymer according to claim 5, characterized in that it is a powder. 8) Application of the biodegradable water-soluble acrylic and / or vinyl polymer and / or copolymer according to claims 1 to 7 to the fields of paper, paints, plastics, oil, drilling fluids, water treatment, detergency , cosmetics, textiles, inks, leather, grinding and / or disintegrating minerals in water.