Chelates and the basics of cleaning SEPAWA Nordic 2017 May 16, Malmö

Transcription

1 Chelates and the basics of cleaning SEPAWA Nordic 2017 May 16, Malmö Dr. Jan Seetz Tech. Development Man.

2 Cleaning process depicted According to internet: Why do detergents need builders? 2

3 Why do detergents need builders? Answer: to improve the detergency power! By binding the hard water ions with a chelating substance 1. Removing the Ca glue which binds stains to the surface dirt dirt Chelate Ca Ca Ca surface surface + Ca-Chelate 3

4 Why do detergents need builders? Answer: to improve the detergency power! By binding the hard water ions with a chelating substance 1. Removing the Ca glue which binds stains to the surface dirt dirt Chelate Ca Ca Ca surface surface + Ca-Chelate 2. Preventing inactivation of anionic surfactants 3. Soften the water improved wetting 4. Dissolving hard water scale Which chelates can be used? 4

5 Main 1 st and 2 nd generation chelates 1 st generation Problems 2 nd generation HOOC HOOC N N COOH COOH EDTA fast biodegradable & non toxic EDTA is not readily biodegradable + labelled No Eco label HOOC HOOC N COOH NTA NTA is a suspect human carcinogen and so labelled. No Eco label STPP STPP contributes to eutrophication. Restricted Eco label 5

6 Main 1 st and 2 nd generation chelates 1 st generation 2 nd generation fast biodegradable & non toxic HOOC HOOC HOOC HOOC N N N COOH COOH EDTA COOH NTA HOOC COOH N s,s EDDS HOOC N N COOH COOH COOH HOOC CH MGDA 3 HOOC GLDA HOOC =strong chelates COOH N N COOH COOH COOH HOOC IDS COOH STPP Which chemical cleaning power is needed? 6

7 Chemical power of detergents Chemical cleaning power is determined by: Type and amount of surfactant Strength and amount of builder / chelate ph of detergent Possible use of oxidizer Chemical power needed is determined by: Your expectations Type of fouling & surface The application (conditions)!! 7

8 Chemical power of detergents Application determines the chemical power needed Time = seconds to max one minute Temp = elevated temperatures Chemical = low strength, ph = 7 Mechanical = brushing In hand dish wash low chemical power needed 8

9 Chemical power of detergents Application determines the chemical power needed Time = long time Temp = elevated temperatures Chemical = low strength, ph= 8-10 Mechanical = rubbing In laundry low chemical power needed 9

10 Chemical power of detergents Application determines the chemical power needed Mech Time = long time Temp = elevated temperatures Chemical = high strength, ph=8-10 Mechanical = low force water jets In ADW high chemical power needed 10

11 Chemical power of detergents Application determines the chemical power needed Time Temp Time = few seconds Temp = ambient temperatures Chemical = high strength, ph >12 Mechanical = water jets / brushes In car cleaning high chemical power needed 11

12 Builder type versus application Ranked in order of chemical power needed Industrial cleaning, CIP Car & truck cleaning Institutional dish wash NTA EDTA HEDTA Sinner's Circle Industrial laundry Home automatic dish wash Home laundry Boosting Liquid laundry compacts Solid Home laundry Hard surface cleaning STPP, Zeolites, Silicates GLDA MGDA Hand dish wash Citrates Low quality liq. laundry compacts Soda ash, cobuilders 12

13 Chelates breaking the bonds Heavy competition for (hard water) metal ions Soil Metal ion Anionic surfactant Surface scale Carbonate 13

14 Ca bound dirt removal Synergistic effect of anionic surfactant and chelating builder Conclusion: better soil removal from hydrophilic surfaces when strong chelating agents are used Lit: laundry detergents, 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim / a pub2 14

15 Dissolving hard water scale (CaCO 3 scale) Lab test The molar efficiency dissolution of CaCO 3 by various chelating agents at ph 8 after 10 minutes * Phosphonate used at same molar ratio as other chelating builders Conclusion: GLDA and MGDA outperforms all others 15

16 Inactivation of anionic surfactants by hard water Influence of builder on precipitate and foam formation 3 drops of liquid soap in medium hard (8dGH) tap water No additives + Na Citrate + GLDA 16

17 Inactivation of anionic surfactants by hard water Experiment with LAS (octylbenzene sulfonate) & Ca 2 LAS-Na + CaCl 2 (LAS) 2 Ca + 2 NaCl 1 Without NTA added 2 With NTA added (half the amount compared with Ca) Lit: K.Tsujil, J. Phys. Chem, 1980, 84,

18 Inactivation of anionic surfactants by hard water Explanation Krafft point The Krafft temperature should be at low as possible! 100 ppm hardness ( 6 dgh) raises the T K of LAS to approx. 70 C water hardness Krafft temperature Krafft temperature Water hardness raises the Krafft point of (an)ionic surfactants to a too high level Lit: Lit: Lit: Lim at all, H&PC Today, p 47,vol. 11(4) July/August

19 Water softening Strength of chelate determines the amount needed What is metal binding strength? Chelating agent + Metal-ion Metal-chelate Chelate Metal-complex Reaction is reversible; giving Equilibrium K = [metal-chelate] [metal-ion] [chelating agent] = Stability constant dependent on a.o. the ph 19

20 Water softening MGDA GLDA Citrate Conclusion: for good softening and cleaning the ph should be as high as possible 20

21 Water softening Strength of chelate determines the amount needed water hardness in ppm CaCO water hardness versus the amount of chelate added 50 ppm CaCO 3 = 2.8 dgh citrate STPP GLDA MGDA EDTA K=3.5 K=5.2 K=6.4 K=7.0 K= ,0 0,5 1,0 1,5 2,0 2,5 3,0 3,5 4,0 4,5 5,0 5,5 6,0 molar equivalent of chelate added 5 ppm CaCO 3 = 0.3 dgh At 5 ppm CaCO 3 : 1 mol GLDA or MGDA 7.3 mol citrate 21

22 Interpretation of lab tests: be careful Be careful with the interpretation of your lab tests Even weak chelates seem to work OK in the soda ash titration method Commercial spots are made on unrealistic clean surfaces Co-builders will trick your eyes! Temperature influences chelating power. 22

23 Interpretation of lab tests: be careful Determining the chelating capabilities: co-builders will trick your eyes Car cleaner formulation 3% formulation ( 8% chelate + 10% caustic) in 97% of 20 FH (=50ppm Mg) water Molar ratio Chelate : Mg = 3 : 1 NTA GLDA GLDA GLDA GLDA AkzoNobel polymer(100% active basis) in formulation 0.1% 0.2% 0.4% 23

24 mg CaCO 3 / g chelate Interpretation of lab tests: be careful Determining the chelating capabilities: influence of the temperature Lab test with CaCO 3 precipitation STPP MGDA GLDA IDS citrate Theoretical CaCO 3 CV T C Conclusion: practical CaCV of GLDA and MGDA are the same at elevated Temp. Source Reckitt Benckiser patent WO2007/

25 Similarity between GLDA and MGDA Wide active ph range & good stability Both are stronger than citrates 25

26 Performance in cleaning tests Home automatic dish wash test 26

27 Similarity between GLDA and MGDA Wide active ph range & good stability Both are stronger than citrates Safe and no hazard classification Swan and Euro Ecolabel compliant Compatible with modern enzymes Improving (the shelf life of) liquid detergents Less turbidity Less oxidation of oils and perfumes Less discoloration Less biocidal or preservatives needed 27

28 Biocidal & Preservative boosting Rationale of the chelates - biocidal synergy EDTA or GLDA / MGDA EDTA-Ca or GLDA-Ca / MGDA-Ca Preservative or Biocidal Ca Ca Ca Ca Ca Ca Ca Ca Ca Ca Ca Ca microorganism Ca Ca Ca Ca Ca Ca Ca Ca Ca Ca Microorganisms are deprived of multivalent cations weakening the outer surface and are more vulnerable for the action of biocidals GLDA & MGDA has been found to be better boosters than EDTA 28

29 Similarity between GLDA and MGDA Wide active ph range & good stability Both are stronger than citrates Safe and no hazard classification Swan and Euro Ecolabel compliant Compatible with modern enzymes Improving (the shelf life of) liquid detergents Less turbidity Less oxidation of oils and perfumes Less discoloration Less biocidal or preservatives needed Improved cleaning results Better color protection / retention of garments Both good in stabilizing oxidation agents in solid detergents Less time / lower temperature / less scrubbing needed 29

30 Performance in cleaning tests Household all purpose cleaner tests on Sheen scrubber According to the German IKW-criteria (SOFW journal, 10, p130, 2004) Tests done by Julius Hoesch GmbH & Co. KG, Germany 4 track apparatus with cleaning cloth Dirt: 75 % peanut oil 23 % kaolin (Aluminum silicate) 2 % carbon black Sprayed on tiles and aged 24h at 110C Cloths wetted with concentrates 30

31 Performance in cleaning tests Household all purpose cleaner tests on Sheen scrubber 1 st reference product: German market leader in all purpose cleaners, solids content = 4.7 % Ingredient list water Sodium alkyl benzene Sulfonate < 3 % according to the SDS Alcohol Perfume Hexyl alcohol 5 EO Fatty alcohol ethoxylate C12-18, 7 EO Phenoxyethanol Sodium citrate C12 C18 fatty acid sodium salt Sodium carbonate Benzyl alcohol Limonene Hexyl Cinnamal Amyl Cinnamal Butylphenyl methylpropional Colorant 31

32 Performance in cleaning tests Household all purpose cleaner scrubber tests Formulation Berol ENV226Plus 9 GLDA 47% 8 ph (with citric acid) 11 Water Balance Active content % 8.7 Cloud point ºC >70 Reference: Der General (5% active content) from Henkel 32

33 Dilution 1:40 40 Strokes Der General ENV226plus / GLDA Recipe with strong chelate show far better cleaning than without chelate 33

34 Dilution 1:20 25 Strokes Der General ENV226plus / GLDA Strong chelate containing recipe almost fully clean in ~ 25 strokes 34

35 Dilution 1:5 5 Strokes Der General Fully clean at >50 strokes ENV226 plus / GLDA 5 strokes Strong chelate containing recipe > 10 times faster than reference 35

36 Performance in cleaning tests Touchless cleaning performance in AmphoChem test Comparative cleaning performance of GLDA / AmphoChem surfactant mixtures 1 start 2 1,5 min Plate smeared with Carbon black Motor oil Diesel Test subjects: 1. Commercial product A total solids ~10% 2. Commercial product B total solids ~10% 3. Ampho mixture total solids =8.5% Ampho mix 1, 5% GLDA 47% 10% 4. Ampho mixture total solids = 8.9% Ampho mix 2, 5% GLDA 47% 10% Dilution = 1:10 3 2,5 min Cleaning with the AmphoChem recipes containing GLDA is superior 36

37 Differences between GLDA and MGDA High solubility of GLDA at low ph Acid cleaners with chelates are now possible 37

38 Solubility under acid conditions Good solubility of MGDA under neutral and alkaline conditions GLDA has exceptional high solubility across the entire ph range 38

39 Differences between GLDA and MGDA High solubility of GLDA at low ph Acid cleaners with chelates are now possible Higher solubility of GLDA at high NaOH levels More concentrated detergents possible 39

40 wt% sodium chelate Solubility under high alkaline conditions Solubility of sodium chelates in 0, 5, 10, 25 and 50 weight% NaOH GLDA NTA EDTA MGDA wt% NaOH Conclusion: GLDA has excellent solubility in caustic and at low Temperature, making compacts possible 40

41 Differences between GLDA and MGDA High solubility of GLDA at low ph Acid cleaners with chelates are now possible Higher solubility of GLDA at high NaOH levels More concentrated detergents possible Lower hygroscopicity of MGDA Advantageous for solid detergents MGDA has lower Mw Good for low temp / short contact time cleaning GLDA provokes less glass corrosion Good for ADW MGDA causes less cloud point issues GLDA is most bio-based / smallest Eco footprint 41

42 Thanks for your attention Questions regarding chelating agents can be addressed to Amphochem, our partner in the Nordics & Baltics 42