POLYURETHANE DISPERSIONS

Abstract

The present invention relates to aqueous dispersions containing at least one polyurethane and at least one compound with a biocidal action, the at least one compound with a biocidal action containing at least one peroxide group and being present in a quantity of between 0.01 and 1,000 mmol/kg, in relation to the total aqueous dispersion, and relates to a process for preparing a biocide-free aqueous polyurethane dispersion, said process comprising at least the steps: (A) preparing an aqueous solution containing at least one polyurethane and at least one compound with a biocidal action, the at least one compound with a biocidal action containing at least one peroxide group and being present in a quantity of between 0.01 and 1,000 mmol/kg, in relation to the total aqueous dispersion; and (B) treating the aqueous dispersion from step (A) with at least one compound with an anti-oxidative action, in order to obtain the biocide-free aqueous polyurethane dispersion, and in addition relates to the use of at least one compound with an anti-oxidative action for treating an aqueous dispersion containing at least one polyurethane and at least one compound with a biocidal action, the at least one compound with a biocidal action containing at least one peroxide group and being present in a quantity of between 0.01 and 1,000 mmol/kg, in relation to the total aqueous dispersion.

Claims

1. An aqueous dispersion comprising at least one polyurethane and at least one compound having a biocidal effect, wherein the at least one compound having a biocidal effect comprises at least one peroxide group and is present in an amount of 0.01 to 1000 mmol/kg, based on the total aqueous dispersion.

2. The aqueous dispersion of claim 1, wherein the at least one polyurethane is based on polyether polyols, polyester polyols, polycarbonate polyols or mixtures thereof.

3. The aqueous dispersion of claim 1, wherein the at least one compound having a biocidal effect is selected from the group consisting of hydrogen peroxide, alkali metal and alkaline earth metal peroxides, sodium hyperoxide, peroxomonosulfuric acid, peroxodisulfuric acid, peracetic acid, sodium percarbonate and mixtures thereof.

4. The aqueous dispersion of claim 1, wherein the at least one polyurethane is present in an amount of 5 to 64% by weight, on the total aqueous dispersion.

5. The aqueous dispersion of claim 1, further comprising additional components selected from the group consisting of: binders, assistants, additives, fillers, auxiliaries, leveling agents, reactive diluents, plasticizers, neutralizing agents, catalysts, auxiliary solvents, thickeners, additives, tackifiers and mixtures thereof.

6. A process for producing a biocide-free aqueous polyurethane dispersion, comprising: (A) providing an aqueous dispersion comprising at least one polyurethane and at least one compound having a biocidal effect, wherein the at least one compound having a biocidal effect comprises at least one peroxide group and is present in an amount of 0.01 to 1000 mmol/kg, based on the total aqueous dispersion, and (B) treating the aqueous dispersion from step (A) with at least one compound having an antioxidant effect in order to obtain the biocide-free aqueous polyurethane dispersion.

7. The process of claim 6, wherein the at least one compound having an antioxidant effect is selected from the group consisting of ascorbic acid, salts of ascorbic acid, cysteine, acetylcysteine, L-glutathione, methionine and mixtures thereof.

8. The process of claim 6, wherein alkali metal salts of ascorbic acid are used as the compound having an antioxidant effect.

9. The process of claim 6, wherein the at least one compound having an antioxidant effect is added in a molar ratio of peroxide (—O—O—) to antioxidant of 0.1 to 10.

10. The process of claim 6, further comprising step (C). after step (B): (C) production of articles, cosmetics, coatings, adhesive layers or adhesives from the biocide-free, aqueous polyurethane dispersion obtained in step (B).

11. The process of claim 6, wherein step (B) is conducted at 5 to 100° C., at 23 to 50° C.

12. (canceled)

13. The aqueous dispersion of claim 4, wherein the at least one polyurethane is present in an amount of 30 to 60% by weight, based on the total aqueous dispersion.

14. The aqueous dispersion of claim 13, wherein the at least one polyurethane is present in an amount of 40 to 50% by weight, based on the total aqueous dispersion.

15. The process of claim 8, wherein the alkali metal salts of ascorbic acid comprises sodium ascorbate.

16. The process of claim 9, wherein the at least one compound having an antioxidant effect is added in a molar ratio of peroxide (—O—O—) to antioxidant of 1 to 3.

17. The process of claim 16, wherein the at least one compound having an antioxidant effect is added in a molar ratio of peroxide (—O—O—) to antioxidant of 1.8 to 2.2.

18. The process of claim 11, wherein step (B) is conducted at 23 to 50° C.

Description

EXAMPLES

Materials and Sources

[0106] Polyester I: polyester diol formed from butane-1,4-diol and adipic acid, OH number 50 [0107] Desmodur® H: hexamethylene-1,6-diisocyanate, Covestro Deutschland AG [0108] Desmodur® I: isophorone diisocyanate, Covestro Deutschland AG [0109] Desmodur® W: 4,4′-diisocyanatodicyclohexylmethane, Covestro Deutschland AG [0110] PolyTHF® 1000: BASF SE [0111] PolyTHF® 2000: BASF SE [0112] Desmodur® DN: hydrophilically modified polyisocyanates based on hexamethylene diisocyanate, NCO content 20% by weight, Covestro Deutschland AG [0113] Preventol® D7: 1.5% by weight aqueous solution of a mixture of 5-chloro-2-methylisothiazolinone/2-methylisothiazolinone (CAS 55965-84-9), Lanxess Deutschland AG [0114] Hydrogen peroxide: 35% by weight aqueous solution, Merck KGaA [0115] Ascorbic acid: Merck KGaA [0116] Sodium ascorbate: Merck KGaA [0117] Cysteine: Merck KGaA [0118] Acetylcysteine: Merck KGaA [0119] L-Glutathione: Merck KGaA [0120] Methionine: Merck KGaA

Methods:

[0121] Unless otherwise stated, the peroxide concentration in mmol/l in the polyurethane-polyurea dispersions always refers to the peroxide group —O—O— having a molecular weight of 32 g/mol.

Determination of the Peroxide Concentration:

[0122] The peroxide concentration or the presence of biocide having an oxidant effect in the polyurethane-polyurea dispersion was determined semi-quantitatively using the peroxide test strips cited below: [0123] Peroxide test 100 to 1000 mg/l H.sub.2O.sub.2, MQuant, Merck KGaA [0124] QUANTOFIX® Peroxide 25, 0 to 25 mg/l H.sub.2O.sub.2, Macherey-Nagel

[0125] The peroxide test 100 to 1000 mg/H.sub.2O.sub.2 from MQuant was only used in the following for the semi-quantitative determination of the peroxide concentration in the polyurethane-polyurea dispersions before adding the reducing agents (additives).

[0126] QUANTOFIX® Peroxide 25 is also suitable for detecting peracetic acid and other organic and free inorganic hydroperoxides and was therefore used to determine the peroxide concentration in the polyurethane-polyurea dispersions after adding the reducing agents (additives).

[0127] Determination of the bacteriological status of the polyurethane-polyurea dispersions:

[0128] the contamination or bacterial growth in the polyurethane-polyurea dispersions was determined using BacTrac 4300 from SY-LAB Geräte GmbH. For this purpose, 1 ml of the polyurethane-polyurea dispersion was poured into the BiMedia 001C measuring cell (order number 41-440011). The measuring cell was sealed with the screw cap (order number 41-440012+) and placed in the measuring station of the BacTrac 4300, which was temperature-controlled to 35° C.

[0129] The multiplication of microorganisms in the dispersion sample is accompanied by an increase of metabolic products. The BacTrac 4300 measuring device uses the alternating current resistance (impedance) of the sample as a measure for determining the metabolic products. The threshold (E) can be set individually. If the threshold value (E) is exceeded, the sample is considered to be sterile. For all measurements, the threshold value (E) was set at 8 and the maximum measurement duration at 50 hours. The temperature of the sample was 35° C. during the measurement. The data in Table 1 refers to the time [h] until the threshold value (E) is reached.

Biocidal Effect (BacTrac Test):

[0130] The polyurethane-polyurea dispersion 1 (PUD 1) contaminated with bacteria was mixed with Preventol D7 (comparative example) and with hydrogen peroxide as biocides. Immediately after adding the biocides, the determination of the bacteriological status of the polyurethane-polyurea dispersions using the BacTrac 4300 was started.

Polyurethane-Polyurea Dispersion 1 (PUD 1):

[0131] 450 g of polyester I were dewatered for 1 hour at 110° C. and 15 mbar. At 80° C., 30.11 g of Desmodur® H and then 20.14 g of Desmodur® I were added. The mixture was stirred at 80 to 90° C. until a constant isocyanate content of 1.15% by weight had been reached. The reaction mixture was dissolved in 750 g of acetone and cooled to 48° C. Into the homogeneous solution was added a solution of 5.95 g of the sodium salt of N-(2-aminoethyl)-2-aminoethanesulfonic acid and 2.57 g of diethanolamine in 65 g of water with vigorous stirring. After 30 minutes, the mixture was dispersed by addition of 700 g of water. Distillative removal of the acetone affords an aqueous polyurethane-polyurea dispersion having a solids content of 40.0% by weight. The polymer present was semicrystalline after drying with a melting temperature of 48° C. and an enthalpy of fusion of 50.4 J/g.

Polyurethane-Polyurea Dispersion 2 (PUD 2):

[0132] 318.8 g of polyester composed of adipic acid, hexanediol and neopentyl glycol having a number-average molecular weight of 1700 g/mol were heated to 65° C. Then 87.9 g of Desmodur® W were added and the mixture was stirred at 125° C. until the actual NCO value had fallen below the theoretical NCO value. The molar ratio of isocyanate groups to hydroxyl groups in the prepolymer formation step was 1.79. The prepolymer was dissolved in 720 g of acetone at 50° C., and then a solution of 33.9 g of diaminosulfonate, 1.6 g of ethylenediamine and 102 g of water was metered in. The subsequent stirring time was 15 minutes. The mixture was dispersed by adding 515 g of water. The acetone was removed by distillation in vacuo. A storage-stable dispersion was obtained, the solids content of which was adjusted to about 40% by weight by adding water.

Polyurethane-Polyurea Dispersion 3 (PUD 3):

[0133] 1077.2 g of PolyTHF® 2000, 409.7 g of PolyTHF® 1000, 830.9 g of Desmophen® C2202 and 48.3 g of polyether LB 25 were heated to 70° C. in a standard stirring apparatus. Subsequently, at 70° C., a mixture of 258.7 g of Desmodur H and 341.9 g of Desmodur I was added over 5 min and the mixture was stirred at 120° C. until the theoretical NCO value had been reached or had fallen slightly below the theoretical NCO value. The finished prepolymer was dissolved with 4840 g of acetone and cooled to 50° C., before a solution of 27.4 g of ethylenediamine, 127.1 g of isophoronediamine, 67.3 g of diaminosulfonate and 1200 g of water was added over 10 min. The post-stirring time was 10 min.

[0134] The mixture was then dispersed by addition of 654 g of water. This was followed by removal of the solvent by distillation under vacuum. The polyurethane dispersion obtained had a solids content of 61.6% by weight.

[0135] The results of the tests of the biocidal effects of the individual biocides used are shown in Table 1 below:

TABLE-US-00001 TABLE 1 Storage for 30 min after 1 1 2 No. Description addition week month months C1 100 g of PUD 1  16.8* 16.1 17.45 17.4 (without biocide) C2 100 g of PUD 1 + 19.3 sterile sterile sterile 0.1 g of Preventol D7 3 100 g of PUD 1 + 36.2 sterile sterile sterile 0.06 g of hydrogen peroxide (35% by weight) 4 100 g of PUD 1 + sterile sterile sterile sterile 0.14 g of hydrogen peroxide (35% by weight) 5 100 g of PUD 1 + sterile sterile sterile sterile 0.29 g of hydrogen peroxide (35% by weight) *Measurement started immediately. In the experiments in which a biocide (Preventol D7 or hydrogen peroxide) was added, the first measurement started 30 minutes after the addition in each case. “Sterile” means that the threshold value (E) in the Bac-Trac test is not exceeded within 50 hours. The numerical values in Table 1 represent the time [h] to reach the threshold value (E).

[0136] The bactericidal effect of hydrogen peroxide is apparent. Immediately after adding 0.14 g of hydrogen peroxide (35% by weight) (corresponds to 14.4 mmol H.sub.2O.sub.2/kg) to the PUD 1, the dispersion is sterile. After adding 0.1% by weight Preventol D 7, sterility is only achieved after 1 week.

Decrease in the Peroxide Concentration by Adding the Additives According to the Invention:

[0137] To the polyurethane-polyurea dispersions 1 to 3 (PUD 1 to 3) were added 340 ppm (=10 mmol/kg), 680 ppm (=20 mmol/kg) or 3400 ppm (=100 mmol/kg) H.sub.2O.sub.2. The H.sub.2O.sub.2 concentration of the dispersions treated in this way was determined semi-quantitatively using the peroxide test 100 to 1000 mg/l H.sub.2O.sub.2, MQuant, Merck KGaA.

[0138] For this purpose, the test strips were dipped into the polyurethane-polyurea dispersion to be measured for 1 second each. After removing the test strips from the dispersion, the test strips were immediately rinsed with ca. 5 ml of distilled water. After a further 30 seconds, the concentration (ppm H.sub.2O.sub.2/l) was determined by comparing the indicator area on the test strip with the comparison scale. The measurement results are shown in Table 2. The ratios listed correspond to the molar ratio of additive to H.sub.2O.sub.2.

TABLE-US-00002 TABLE 2 10 mmol of H.sub.2O.sub.2, corresponding to 0.97 g of H.sub.2O.sub.2 (35% by weight in water)/kg PUD 1 dispersion, corresponds mathematically to 340 ppm H.sub.2O.sub.2, measurement result 400 ppm H.sub.2O.sub.2, in each case before addition of the additive Measured concentration H.sub.2O.sub.2 [ppm] Directly 1 day 3 days 1 week 2 weeks Amount Molar after after after after after of ratio adding adding adding adding adding additive additive: the the the the the No. Additive [g] H.sub.2O.sub.2 additive additive additive additive additive  6.1 Ascorbic acid 0.88 0.5:1   2 to 5 2 to 5 2 to 5 2 to 5 10  6.2 Ascorbic acid 1.76 1:1 2 to 5 2 to 5 2 ≤0.5 ≤0.5  6.3 Ascorbic acid 3.52 2:1 <2 ≤0.5 ≤0.5 ≤0.5 ≤0.5  7.1 Na ascorbate 0.95 0.5:1   2 2 2 2 10  7.2 Na ascorbate 1.89 1:1 2 2 0.5 to 2   ≤0.5 ≤0.5  7.3 Na ascorbate 3.78 2:1 <2 ≤0.5 ≤0.5 ≤0.5 ≤0.5  8.1 Cysteine 0.61 0.5:1   10 10 10 10 10  8.2 Cysteine 1.21 1:1 10 10 10 10 10  8.3 Cysteine 2.42 2:1 10 10 10 10 10  9.1 Acetylcysteine 0.82 0.5:1   10 5 5 5 10  9.2 Acetylcysteine 1.63 1:1 10 5 5 5 10  9.2 Acetylcysteine 3.26 2:1 10 5 5 5 2 10.1 L-Glutathione 1.54 0.5:1   10 10 10 10 10 10.2 L-Glutathione 3.07 1:1 10 10 10 10 10 10.3 L-Glutathione 6.14 2:1 10 10 10 10 10 11.1 Methionine 0.75 0.5:1   10 10 10 10 10 11.2 Methionine 1.49 1:1 10 10 10 10 10 11.3 Methionine 2.98 2:1 10 ≤0.5 ≤0.5 ≤0.5 ≤0.5

TABLE-US-00003 TABLE 3 20 mmol of H.sub.2O.sub.2, corresponding to 1.94 g of H.sub.2O.sub.2 (35% by weight in water)/kg PUD 1 dispersion, corresponds mathematically to 680 ppm H.sub.2O.sub.2, measurement result 800 ppm H.sub.2O.sub.2, in each case before adding the additive Measured concentration H.sub.2O.sub.2 [ppm] Directly 1 day 3 days 1 week 2 weeks Amount Molar after after after after after of ratio adding adding adding adding adding additive additive: the the the the the No. Additive [g] H.sub.2O.sub.2 additive additive additive additive additive 12.1 Ascorbic acid 0.88 0.5:1   2 to 5 2 2 2 10 12.2 Ascorbic acid 1.76 1:1 2 2 ≤0.5 <0.5 <0.5 12.3 Ascorbic acid 3.52 2:1 2 <0.5 <0.5 <0.5 <0.5 13.1 Na ascorbate 0.95 0.5:1   2 2 2 5 10 13.2 Na ascorbate 1.89 1:1 2 2 <0.5 <0.5 <0.5 13.3 Na ascorbate 3.78 2:1 <2 <0.5 <0.5 <0.5 <0.5 14.1 Cysteine 0.61 0.5:1   10 10 10 10 10 14.2 Cysteine 1.21 1:1 10 10 10 10 10 14.3 Cysteine 2.42 2:1 10 10 10 10 10 15.1 Acetylcysteine 0.82 0.5:1    5 to 10 5 5 5 5 15.2 Acetylcysteine 1.63 1:1  5 to 10 5 5 5 5 15.2 Acetylcysteine 3.26 2:1  5 to 10 5 5 5 5 16.2 L-Glutathione 1.54 0.5:1   10 10 10 5 10 16.2 L-Glutathione 3.07 1:1 10 10 10 5 10 16.3 L-Glutathione 6.14 2:1 10 10 10 5 <0.5 17.1 Methionine 0.75 0.5:1   10 10 10 10 10 17.2 Methionine 1.49 1:1 10 10 10 10 10 17.3 Methionine 2.98 2:1 10 <0.5 <0.5 <0.5 <0.5

TABLE-US-00004 TABLE 4 100 mmol of H.sub.2O.sub.2, corresponding to 9.71 g of H.sub.2O.sub.2 (35% by weight in water)/kg PUD 1 dispersion, corresponds mathematically to 3400 ppm H.sub.2O.sub.2, measurement result >1000 ppm H.sub.2O.sub.2, in each case before adding the additive Measured concentration H.sub.2O.sub.2 [ppm] Directly 1 day 3 days 1 week 2 weeks Amount Molar after after after after after of ratio adding adding adding adding adding additive additive: the the the the the No. Additive [g] H.sub.2O.sub.2 additive additive additive additive additive 18.1 Ascorbic acid 0.88 0.5:1 <0.5 <0.5 <0.5 <0.5 2 18.2 Ascorbic acid 1.76 1:1 <0.5 <0.5 <0.5 <0.5 <0.5 18.3 Ascorbic acid 3.52 2:1 <0.5 <0.5 <0.5 <0.5 <0.5 19.1 Na ascorbate 0.95 0.5:1 <0.5 <0.5 <0.5 <0.5 10 19.2 Na ascorbate 1.89 1:1 <0.5 <0.5 <0.5 <0.5 <0.5 19.3 Na ascorbate 3.78 2:1 <0.5 <0.5 <0.5 <0.5 <0.5 20.1 Cysteine 0.61 0.5:1 5 5 5 10 5 20.1 Cysteine 1.21 1:1 5 5 5 10 5 20.1 Cysteine 2.42 2:1 5 5 5 10 25 21.1 Acetylcysteine 0.82 0.5:1 5 2 to 5 2 to 5 5-10 5 21.1 Acetylcysteine 1.63 1:1 5 2 to 5 2 to 5 5-10 5 21.1 Acetylcysteine 3.26 2:1 5 2 to 5 2 to 5 10 0.5-2 22.1 L-Glutathione 1.54 0.5:1 5-10  5 to 10  5 to 10 10 5 22.2 L-Glutathione 3.07 1:1 5-10  5 to 10  5 to 10 10 5 22.3 L-Glutathione 6.14 2:1 5-10  5 to 10  5 to 10 10 <0.5 23.1 Methionine 0.75 0.5:1 10  5 to 10 10 10 10 23.2 Methionine 1.49 1:1 10  5 to 10 10 10 10 23.3 Methionine 2.98 2:1 10 <0.5 <0.5 <0.5 <0.5

TABLE-US-00005 TABLE 5 10 mmol of H.sub.2O.sub.2, corresponding to 0.97 g of H.sub.2O.sub.2 (35% by weight in water)/kg PUD 2 dispersion, corresponds mathematically to 340 ppm H.sub.2O.sub.2, measurement result 400 ppm H.sub.2O.sub.2, in each case before adding the additive Measured concentration H.sub.2O.sub.2 [ppm] Directly 1 day 3 days 1 week 2 weeks Amount Molar after after after after after of ratio adding adding adding adding adding additive additive: the the the the the No. Additive [g] H.sub.2O.sub.2 additive additive additive additive additive 24.1 Na ascorbate 0.95 0.5:1 2 2 <0.5 <0.5 <0.5 24.2 Na ascorbate 1.89 1:1 2 <0.5 <0.5 <0.5 <0.5 24.3 Na ascorbate 3.78 2:1 2 <0.5 <0.5 <0.5 <0.5

TABLE-US-00006 TABLE 6 20 mmol of H.sub.2O.sub.2, corresponding to 1.94 g of H.sub.2O.sub.2 (35% by weight in water)/kg PUD 2 dispersion, corresponds mathematically to 680 ppm H.sub.2O.sub.2, measurement result 800 ppm H.sub.2O.sub.2, in each case before adding the additive Measured concentration H.sub.2O.sub.2 [ppm] Directly 1 day 3 days 1 week 2 weeks Amount Molar after after after after after of ratio adding adding adding adding adding additive additive: the the the the the No. Additive [g] H.sub.2O.sub.2 additive additive additive additive additive 25.1 Na ascorbate 1.89 0.5:1   2 2 2 2 2 25.2 Na ascorbate 3.78 1:1 2 <0.5 <0.5 <0.5 <0.5 25.3 Na ascorbate 7.56 2:1 2 <0.5 <0.5 <0.5 <0.5

TABLE-US-00007 TABLE 7 100 mmol of H.sub.2O.sub.2, corresponding to 9.71 g of H.sub.2O.sub.2 (35% by weight in water)/kg PUD 2 dispersion, corresponds mathematically to 3400 ppm H.sub.2O.sub.2, measurement result >1000 ppm H.sub.2O.sub.2, in each case before adding the additive Measured concentration H.sub.2O.sub.2 [ppm] Directly 1 day 3 days 1 week 2 weeks Amount Molar after after after after after of ratio adding adding adding adding adding additive additive: the the the the the No. Additive [g] H.sub.2O.sub.2 additive additive additive additive additive 26.1 Na ascorbate 9.45 0.5:1   <0.5 <0.5 <0.5 2 2 26.2 18.9 1:1 <0.5 <0.5 <0.5 <0.5 <0.5 26.3 37.8 2:1 <0.5 <0.5 <0.5 <0.5 <0.5

TABLE-US-00008 TABLE 8 10 mmol of H.sub.2O.sub.2, corresponding to 0.97 g of H.sub.2O.sub.2 (35% by weight in water)/kg PUD 3 dispersion, corresponds mathematically to 340 ppm H.sub.2O.sub.2, measurement result 400 ppm H.sub.2O.sub.2, in each case before adding the additive Measured concentration H.sub.2O.sub.2 [ppm] Directly 1 day 3 days 1 week 2 weeks Amount Molar after after direct after after of ratio adding adding addition adding adding additive additive: the the of the the the No. Additive [g] H.sub.2O.sub.2 additive additive additive additive additive 27.1 Na ascorbate 0.95 0.5:1   10 to 25 10 to 25 10 to 25 — — 27.2 Na ascorbate 1.89 1:1  5 to 10 <0.5 <0.5 — — 27.3 Na ascorbate 3.78 2:1 2 <0.5 <0.5 — —

TABLE-US-00009 TABLE 9 20 mmol of H.sub.2O.sub.2, corresponding to 1.94 g of H.sub.2O.sub.2 (35% by weight in water)/kg PUD 3 dispersion, corresponds mathematically to 680 ppm H.sub.2O.sub.2, measurement result 800 ppm H.sub.2O.sub.2, in each case before adding the additive Measured concentration H.sub.2O.sub.2 [ppm] Directly 1 day 3 days 1 week 2 weeks Amount Molar after after direct after after of ratio adding adding addition adding adding additive additive: the the of the the the No. Additive [g] H.sub.2O.sub.2 additive additive additive additive additive 28.1 Na ascorbate 1.89 0.5:1   10 to 25 10 to 25 10 to 25 — — 28.2 Na ascorbate 3.78 1:1 2 to 5 <0.5 <0.5 — — 28.3 Na ascorbate 7.56 2:1 <0.5 <0.5 <0.5 — —

TABLE-US-00010 TABLE 10 100 mmol of H.sub.2O.sub.2, corresponding to 9.71 g of H.sub.2O.sub.2 (35% by weight in water)/kg PUD 3 dispersion, corresponds mathematically to 3400 ppm H.sub.2O.sub.2, measurement esult >1000 ppm H.sub.2O.sub.2, in each case before adding the additive Measured concentration H.sub.2O.sub.2 [ppm] Directly 1 day 3 days 1 week 2 weeks Amount Molar after after direct after after of ratio adding adding addition adding adding additive additive: the the of the the the No. Additive [g] H.sub.2O.sub.2 additive additive additive additive additive 29.1 Na ascorbate 9.45 0.5:1   0.5 to 2 0.5 to 2 10 to 25 — — 29.2 Na ascorbate 18.9 1:1 <0.5 <0.5 <0.5 — — 29.3 Na ascorbate 37.8 2:1 <0.5 <0.5 <0.5 — —

[0139] All values in the tables were determined using QUANTOFIX® peroxide 25.0 to 25 mg/l H.sub.2O.sub.2. “-” means that no measurements were carried out.

[0140] The mode of action of the additives is obvious. Immediately after the addition of these additives, the H.sub.2O.sub.2 concentration drops significantly below the value of the dispersion prior to the addition of the additives.

Biocidal Effect and Destruction of the Biocidal Effect by Adding the Antioxidant (BODE Dip Slides Combi Test):

[0141] The investigations are carried out according to the package insert (instructions for use) enclosed with the test. The lid of the BODE Dip Slide Combi test tube with the culture medium carrier is unscrewed and removed from the test tube. The culture medium carrier is immersed in the polyurethane-polyurea dispersion for 5 to 10 seconds. Excess polyurethane-polyurea dispersion is left to drain off well. The lower edge of the culture medium carrier is dabbed with a clean filter paper. The culture medium prepared in this way is returned to the test tube and the lid screwed on. The test tube with the prepared culture medium is stored in a climate cabinet at 35° C. Bacterial growth on the culture medium can be determined by visually comparing the culture medium carrier with the comparison scale shown in the package insert.

[0142] The scale depicts the number of CFU (colony forming units) between 10.sup.2 CFU and 10.sup.7 CFU. Up to 10.sup.4 CFU the sample is considered to be very weakly to weakly contaminated, from 10.sup.6 CFU the sample is considered to be heavily to very heavily contaminated.

[0143] The polyurethane-polyurea dispersion PUD 1 (experiment 30) contaminated with bacteria was admixed with 20 mmol/kg or 100 mmol/kg hydrogen peroxide solution (experiment 31 or 32).

[0144] Immediately after the addition of the hydrogen peroxide solution, sodium ascorbate solution was added to destroy the hydrogen peroxide (experiment 33 and 34). Immediately after the addition of sodium ascorbate solution, the samples were inoculated with 10 g of contaminated PUD 1 (experiment 35 and 36). The results are shown in Table 11:

TABLE-US-00011 TABLE 11 Results of the BODE Dip Slides Combi tests Experiment 30 31 32 33 34 35 36 PUD 1 [g] 100 99.81 99.03 99.81 99.03 99.81 99.03 Hydrogen peroxide — 0.19 0.97 0.19 0.97 0.19 0.97 (35% in water) [g] Sodium ascorbate solution — — — 7.56 37.8 7.56 37.8 (10% in water) [g] PUD 1 [g] — — — — — 10 10 Dip Test [t] 2 7 7 7 7 7 7 days days days days days days days Result of dip test [CFU] 10.sup.7 <10.sup.2 <10.sup.2 10.sup.5 10.sup.5 10.sup.7 10.sup.7 All data in the table in [g]

[0145] Contamination of PUD 1 with bacteria is evident. After just 2 days of the dip test, the sample (experiment 30) is evaluated at 107 CFU, i.e. there is heavy to very heavy contamination.

[0146] The effect of hydrogen peroxide is also confirmed in the dip test. After adding 20 mmol/kg or 100 mmol/kg hydrogen peroxide (35% solution in water) to the contaminated PUD 1, a value of <10.sup.2 CFU, i.e very weak to weak contamination, is found after 7 days (experiments 31 and 32).

[0147] Destruction of hydrogen peroxide after adding 10% sodium ascorbate solution (molar ratio of sodium ascorbate: peroxide=2:1) is also evident, see experiments 33 and 34.

[0148] By inoculating the initially sterile samples with PUD 1, heavy to very heavy contamination of the sample is found after 7 days, see experiments 35 and 36.