Additive groups. Applications. Rheology modifiers. Defoamers. Dispersants. Wetting and leveling agents. Conclusion

Transcription

1 Jörg Wollschläger

2 Additive groups Applications Rheology modifiers Defoamers Dispersants Wetting and leveling agents Conclusion 2

3 Filmforming agent (polymer/ resin) non volatile Additives Pigments and Extenders/Fillers volatile Solvents (organic and /or water) 3 From BASF-handbook of coatings technology

4 - Defoamer - Dispersant - Wetting agent - Leveling agent - Rheology additive - Catalyst e.g. dryer for alkyds, DBTL for 2K PU - Film formation aids different types of solvents - Corrosion inhibitor organic and inorganic chemicals - UV absorber HALS - Anti-oxidant e.g. anti-skinning agents for drying alkyds - Matting agent waxes, silica - Adhesion improver silanes, resins - Anti-fouling organo-tin compounds - Preservative biocide, fungicide 4 This is not a complete listing of additives

5 Liquid phase Substrate Binderemulsion Micelle Defoamer Emulsified Pigment/ Dispersant Pigment Wetting/ leveling additive 5

6 Types of Coatings: Architectural, Decorative, Industrial, Printing Inks, Dry mixes, Adhesives Application devices: Paint roller, brush, airless- spray gun, Spray booth, trowel, Dip-Coating, Flow-coating, Printing machines Substrates: Concrete, Wood, Metal, Bricks, Gypsum, Lime, Wallpaper, Glass, Plastics, Paper Binder types: -Acrylates, Styrene Acrylates -Polyurethans, Epoxies -Vinyl Acetate Copolymers -Water Glass -Silicone Resins Pigments : -TiO 2 - Iron Oxides - Fillers - Carbon Black - Organic Pigments - Functional Pigments 6

7 Paint roller Roller for enamels Brush 7

8 Airless spray gun with air directed spray Air assisted flow cup spray gun HVLP pressurised cup spray gun Spray cabin 8

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10 Rheology modifiers Defoamers Dispersants Wetting and leveling agents 10

11 viscosity Dilatant (shear thickening) e.g. starch dispersion Newtonian (ideal flow behaviour) e.g. water, oil shear rate Pseudoplastic, thixotropic (shear thinning) e.g. ketchup 11

12 transport, storage, sedimentation levelling, sagging stirring, flow, general appearance roller application, brushing, spraying s -1 12

13 Sagging Spatter Color strength Poor! Poor! Poor! Roller/brush marks Levelling Hiding power Poor! Poor! Poor! 13 Influenced by resulting rheology Influenced by chemical structure

14 Inorganic thickeners (organo modified) for solvent based and water based paints Bentonite Silica Organo clays Organic thickeners for water based systems Non Associative Thickeners Cellulose derivatives Alkali swellable emulsions Associative Thickeners Hydrophobically modified cellulose ethers Hydrophobically modified alkali swellable emulsions Hydrophobically modified polyurethanes CE ASE HMHEC HASE HEUR 14

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16 mpa s without thickener 100 2,6% TAFIGEL PUR 40 4,16% TAFIGEL PUR 85 5,2% TAFIGEL PUR 54 equal active substance (1.04 %) 10 5,2% TAFIGEL PUR , /s shear rate.

17 Flow cup(4mm) Brookfield ICI cone/plate Rotation/Oscillation rheometer transport, storage, sedimentation leveling, sagging stirring, flow, general appearance roller application, brushing, spraying s -1 17

18 Sagging resistance higher than 300 µm Sagging resistance 210 µm 18

19 Indication for changes during storage General appearance Quality control Dilution adjustment Flow cup (DIN; FORD; ISO) Krebs-Stormer Brookfield 19

20 Predict behavior and properties of coatings during production, storage, transport and application Speed up development, additive choice and explanation of unexpected behavior of materials 20

21 Rheology modifiers Defoamers Dispersants Wetting and leveling agents 21

22 What is foam? Foam is a (stable) dispersion of a gas phase in a liquid system Surfactants are necessary in order to stabilise a gas bubble (hydrophobic particle) in an aqueous environment Defoamers are necessary in order to destroy the foam or to prevent foam formation 22

23 pure water surfactant containing water 23

24 surfactant molecules hydrophobic particle 24

25 Production Application Production vessels are not optimally filled Dispersing process is inefficient Formation of pinholes Reduced protection Reduction of gloss and transparency Negative effect on leveling Aspect Optical aspect negative 25

26 Mechanical processes during production grinding, stirring, pumping, filling Emulsion polymers / binders with emulsifiers problem mainly in waterbased systems Presence of surface active compounds wetting and dispersing agents, thickeners, leveling agents, Presence of other paint ingredients solvents, pigments & fillers with included air,... Application roller, curtain, flow, circulation, printing,... Porous substrates 26

27 Carriers Hydrophobic ingredients Oils, water, solvents, modified Polyether siloxanes, Oleo-ABCs Waxes, hydrophobic silica, metal soaps, paraffin, amides, polyalkylene glycols, polyurethanes 75 90% 5 10% Emulsifiers Surfactants 0 5% Others Biocides, thickeners, protective colloids 0 20% 27

28 Carriers Hydrophobic ingredients Emulsifiers Others Transport of active ingredients to the surface, spread on the surface and prevent formation of a surfactant s layer Absorb surfactant molecules and enter into lamella double layer Adjust emulsify ability (compatibility) of the defoamers in the system Support spreading of the defoamers at the surface Adjust of viscosity, prevent separation, fouling 28

29 1.0% defoamer Red Devil-Test % air Compatibility Roll wet / dry Leveling 100 µm (wet) on glass Gloss Overall CR OP 20 Blank 27,3% homogeneous 2 / 2 10 n n 74.8 Competitor 10,6% homogeneous 9 / 10 9 n-f n 72.8 AGITAN 155 6,5% homogeneous 9 / n n 75.8 AGITAN ,9% homogeneous 9 / n n 74.7 AGITAN 158 4,1% homogeneous 10 / n n

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32 Rheology modifiers Defoamers Dispersants Wetting and leveling agents 32

33 Colorants Dyestuff: soluble in the application media Pigments: insoluble particles Organic pigments Phthalocyanine AZO Pigment Perylen Chinacridone Inorganic pigments: Titanium dioxide Fillers (CaCo 3, talcum) Iron Oxides, earth pigment Carbon black Bismuth vanadate Effect pigments (e.g. metallics, pearlescent) Functional pigments (e.g. anticorrosive, conductive) 33

34 Particle size (µm) Surface (m²/g) Inorganic Pigments and Fillers 0,3 5, Calcium Carbonate Titanium Dioxide 0,3 1, Standard Iron Oxide Red 0,1 1,0 Organic Pigments 0,05 1, Phthalo Cyanine Blue 0,06 0, Carbon Blacks 0,05 0, furnace black 0,05 0, gas black 0,005 0, Transparent inorganic pigments - transparent Iron Oxide Red 0,001 0,

35 pigment in powder form wetted agglomerate dispersed pigment 35

36 Wetting of pigments Replacement of air and humidity Support of grinding Short dispersing time, optimum degree of grinding Reduction of grind viscosity High pigment loading, flowability Stabilization of the dispersion Color strength, gloss, color shade stability Compatibility with resins No flocculation (Rub-Out), broad application No influence on coatings Water resistance, film hardness, scrub resistance 36

37 10 min. disperse with a Red Devil Shaker Red Devil Shaker % Dispersant 37

38 Competitor 1 Competitor 2 Competitor 3 Competitor 4 Color Black FW % Anionic Copolymer EDAPLAN 492 % Dispersant on Pigment 112.5% 112.5% 112.5% 50% 128.6% 128.6% % Active Content on Pigment Appearance of Paste after 1 Week at 40 C without sediment low viscous without sediment low viscous Clear Coating 45% without sediment low viscous without sediment medium viscous without sediment low viscous without sediment low viscous Color Strength Gloss Haze Flocculation/Specks White PU Acrylic Coating Color Strength Rub-Out ( E) Gloss

39 Colorimetric datas: Color strength, color shade (CIELAB), metamerism Viscosity, flowing properties: Viscosimeter (Brookfield/Krebs-Stormer), Rheometer cone-plate, flow cup Particle size: Grindometer, particle size measurement Incorporation, compatibility: White base, clear system Application: Printing, spraying, roller coating Drying behavior, exactness of dosing (tinting machines) Rub-out Sedimentation/ Antisettling Storage stability Stability of color shade Gloss Transparency / hiding power ph value 39

40 gloss haze particle size (µm) Dispersing time (min)

41 Rheology modifiers Defoamers Dispersants Wetting and leveling agents 41

42 Fish Eyes Cracking Pinholes Sagging Brush/ Roller Marks Orange Peel 42

43 Volume reduction during drying Solvent evaporation Film weight / Film thickness Rheology / Viscosity Application Method Drying time / Open time Poor defoaming Contaminants Surface tension of the liquid coating is too high Variation of surface tension / unequal surface tension in the wet film 43

44 ...that can not be solved with wetting agents: Cracking Sagging Roller / Brush Marks Pinholes.....that can be solved with wetting agents: Craters Fish Eyes Orange Peel Compatibility.. 44

45 What is the important criteria for good wetting: The lower the contact angle q, the better the wetting of the substrate The contact angle is influenced by the surface tension (s) of the liquid and the surface energy (s) of the substrate A liquid spreads on a substrate, if the surface tension of the liquid is lower compared to the surface energy of the substrate S liquid < S substrate 45

46 Liquids; Solvents surface tension S [mn/m] Substrate surface energy S [mn/m] xylene 32 glass 73 butyl glycol 27 PVC butyl acetate 25 phosphated steel water 72 aluminium ~ 40 water + 0,5%METOLAT polystyrene polyester 43 Wetting: S coating < S substrate 46

47 or good hydrophobing 47

48 Improvement of color acceptance in a silicone emulsion paint Pigment concentrate based on PY 42 (Iron oxide yellow) without additive 1% METOLAT 367 added to the paint 48

49 waterbased UV inkjet ink + additive compatibility after 24 h leveling 12 µm on black white charts recirculation test % foam after surface tension overall cr op [mn/m] 1 min 5 min 10 min 1 min collapse without additive homogeneous 8 f n reference sample homogeneous 8 s n % current LA homogeneous 9 f n % current LA 0.05% current defoamer homogeneous 7 s n % EDAPLAN LA 403 homogeneous 10 n n % METOLAT 362 streaks 4 m n 0.5% METOLAT 366 streaks 2 m n 0.5% EDAPLAN LA 452 homogeneous 9 f n % AGITAN E % EDAPLAN LA 452 streaks 4 m n % AGITAN % EDAPLAN LA 452 streaks 2 m n % AGITAN % EDAPLAN LA 452 homogeneous 8 f n

50 Substrate wetting Dynamic interfacial tension Static interfacial tension 50 Contact angle

51 REACH CLP label-free FDA chapters, like , Swiss Ordinance Decopaint guideline VOC reduction Biocide guidelines Eco label like EU-flower, Blue Angel, Nordic Swan Low emission wall paints BfR chapters Renewable biobased green chemistry 51

52 Interaction of different additive groups in the formulation Synergistic effects potentiating or no/negative effect Chemical composition and reactions Application parameters and drying conditions Regulatory requirements Price/ Performance Finding the right balance!!! 52

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54 54 Please feel free to ask questions

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