Introduction to film formation for SB & WB technologies

Transcription

1 Introduction to film formation for SB & WB technologies

2 Solvent Borne

3 Key Characteristics of SB technologies Low to medium molecular l weight polymers dissolved d in various solvents (Mw = ) SC = % Need to be crosslinked to fully develop final properties O 2, Isocyanate, Melamine 3 I.Bétremieux, C.Chambat, G.Delmas, Steel coat, 18th june 2012

4 Key properties of Solvenborne technologies Liquid form Ease of formulation Ease of application Rheology newtonian or thixotropic Open time directly linked to the solvent INGREDIENTS Weight Volume Function Supplier Disperse at high speed 1 SYNOLAC 4013 WD ,76 337,94 High solid long oil alkyd resin ARKEMA 2 ANTI TERRA 206 2,44 2,60 Dispersing Agent BYK CHEMIE 3 TIOXIDE TR ,37 86,84 Pigment : Titanium dioxide HUNSTMAN Addition under stirring 4 SYNOLAC 4013 WD ,79 212,12 High solid long oil alkyd resin ARKEMA 5 OCTA SOLIGEN 69 4,17 3,83 Driers OMG Group 6 OCTA SOLIGEN CALCIUM 10 basique 4,17 4,25 Drier OMG Group 7 BORCHI NOX M 2 2,85 3,10 Anti-skinning agent OMG Group Viscosity adjustment 8 SPIRDANE D40 149,45 194,09 Solvent TOTAL Total 1000,00 844,76 Dry film Bind all the formulation together Adhesion Aspect (Gloss) 2 0 Durability Contrainte (MPa) Déformation (%) j à TA +14j à 50 C j à TA +14j à 50 C j à TA +14j à 50 C j à TA +14j à 50 C j à TA+14j à 50 C E' ( ) [Pa] Temp [ C] Typical properties of an homogeneous crosslinked polymer tan_delta ( ) [ ] 4 I.Bétremieux, C.Chambat, G.Delmas, Steel coat, 18th june 2012

5 Solvent-borne alkyds film formation Solvent-borne alkyds = Continuous process 100 alkyd = pre-polymer p soluble in the solvent I - Evaporation of the solvent solvent evaporates slowly viscosity increases gradually 10 speckle ra ate (Hz) 1 II - Siccativation O 2 «reacts» with the C in α of the C=C tri-dimensional network Tg increase 0,1 Long open time : possible to solubilise the non siccativated pre-polymer polymer 0, time (min) Diffusion Wave Spectroscopy of the film formation of an solventborne alkyd (made for Cray Valley on Horus, Formulaction, Alice Brun) New chemical bonds between FA 5 I.Bétremieux, C.Chambat, G.Delmas, Steel coat, 18th june 2012

6 Water Borne

7 Key Characteristics of WB Technologies COO - Na + SO4 - Na + (POE)n High to very high Molecular weight polymers dispersed and stabilized with surfactants in water 30% < SC < 68% 30 nm < Ø <700nm Viscosity : Solid content, particle size, interaction between particles Can be crosslinked but can also be used without crosslinking (thermoplastic) 7 I.Bétremieux, C.Chambat, G.Delmas, Steel coat, 18th june 2012

8 ) ] ) Key properties of WB technologies Ref: DECO-CC Liquid form Low viscosity although high molecular weight polymer Very low VOC (< 2000ppm) Formulation for final application more complex Application conditions more controlled INGREDIENTS Weight Volume Function Supplier 1 CRAYMUL ,00 592,45 acrylic dispersion ARKEMA add the millbase 2 WATER 52,00 52,00 solvent 3 ACTICIDE MBS 2,00 1,94 biocide THOR CHEMIE 4 BYK 028 1,50 1,44 Defoamer BYK 5 COADIS TM 123 K 10, ,26 dispersing agent COATEX 6 TIONA ,00 51,22 TiO2 CRISTAL GLOBAL Add under stirring 7 WATER 53,87 53,87 solvent adjust ph>8,5 8 NaOH, 20% 7,09 5,81 9 COAPUR TM ,36 29,20 PU associative thickener COATEX 10 COAPUR TM 830 W 4,18 3,95 PU associative thickener COATEX 11 FOAMSTAR A 38 1,00 1,05 Defoamer COGNIS Total 1000,00 802,19 PAINT CHARACTERISTICS : DRY FILM CHARACTERISTICS : Density (g/cm³) 1,25 Solids Density (g/cm³) 1,67 Weight % Solids (%) 49,40 PVC (additive included) (%) 17,29 Volume % Solids (%) 36,93 PVC (minus additive) (%) 18,01 VOC (water incl.) (g/l) 0 Dried film Bind all the formulation together Adhesion Tensile Strength Mechanical properties, 20 MPa 8 10 durability, infinity of possibilities 5 Can t be high gloss E' ( [Pa a] Tα 1= 10 C Tα= 54 C Tα 2 = 111 C tan(δ) ( [ ] 10 1 Elongation % Temp [ C] Warning: Overlay units don't match, Time 8 I.Bétremieux, C.Chambat, G.Delmas, Steel coat, 18th june 2012

9 Water-borne Acrylics film formation Water-borne Acrylics = Discontinuous process The polymer is not soluble in water : solid particles dispersed in water (surfactant) 10 I : Evaporation of water 1 II : Coalescence : closed packed particles speckle rate (Hz) 01 0,1 III : Particles fusion 0,01 Short open time : impossible to solubilise polymer IV : Inter-diffusion 0, time (min) Diffusion Wave Spectroscopy of the film formation of an acrylic dispersion (made for Cray Valley on Horus, Formulaction, Alice Brun) 9 I.Bétremieux, C.Chambat, G.Delmas, Steel coat, 18th june 2012

10 Water-borne Acrylics film formation Water-borne Acrylics : A 4 step mechanism - view from the top 30 min 4hours 400 nm 11 hours 24 hours 10 I.Bétremieux, C.Chambat, G.Delmas, Steel coat, 18th june 2012

11 Water-borne Acrylics film formation Water-borne Acrylics : A 4 step mechanism - view from the front II or I I At the surface, II - Coalescence : closed packed particles Deeper in the wet film : I - Evaporation of water 11 I.Bétremieux, C.Chambat, G.Delmas, Steel coat, 18th june 2012

12 Water-borne Acrylics film formation Water-borne Acrylics : A 4 step mechanism - view from the front III or II II I Film formation steps take place at the same time depending where you observe the film Film formation requires energy for the evaporation of the water it takes it from the substrate there is a temperature gradient in the wet film 12 I.Bétremieux, C.Chambat, G.Delmas, Steel coat, 18th june 2012

13 Water-borne Acrylics film formation IV - Interdiffusion IV- Coalescence only if T >MFFT Inter-diffusion (autohesion) of polymer chains from one particle to the other Formation of a tri-dimensional network Entanglement and/or self-crosslinking T >MFFT 13 I.Bétremieux, C.Chambat, G.Delmas, Steel coat, 18th june 2012 autohesion zone : some nanometers concerns ONLY polymer chains at the surface of the particle

14 Water-borne Acrylics film formation Critical parameters & their impact on film formation Water evaporation rate (temperature / humidity) - the more slowly the evaporation, the better the film formation Particle size - capillary forces : the smaller the particles, the lower the MFFT Charges around the particles (initiators, iti t surfactant, t neutralisation ti base) - electrostatic repulsions : the lower the charges, the easier the film formation Mobility of the polymer chains at the surface of the particle - Molecular weight the lower the Mw, the more mobile the chains, the better the film formation - Tg (glass transition temperature) the lower their Tg, the more mobile the chains, the better the film formation 14 I.Bétremieux, C.Chambat, G.Delmas, Steel coat, 18th june 2012

15 Water-borne Acrylics film formation Example of film formation Two Acrylic dispersions with same MFFTs CRAYMUL 2138 Competitive low MFFT acrylic P Atomic Force Microscopy, emulsions dried 1 day at 5 C / 70% HR Low Mw of surface oligomers 15 I.Bétremieux, C.Chambat, G.Delmas, Steel coat, 18th june 2012

16 Water-borne Acrylics film formation 500µm Macroscopic aspect : correct Microscopic aspect : deep cracks the film is not correctly formed old generation of Core-Shells Why? To be continued Macroscopic aspect : «opaque» : mud -cracking Microscopic aspect : cracks at the surface the film is formed but not perfectly at its surface 500µm +1% of a hygroscopic compound Macroscopic aspect : perfect Microscopic aspect : perfect the film is formed through its whole thickness 500µm Water evaporates more slowly What impact of the film formation on properties? 16 I.Bétremieux, C.Chambat, G.Delmas, Steel coat, 18th june 2012

17 Film formation and mechanical properties 6 Contrainte (MPa) µm Déformation (%) Contrainte (M Pa) µm +1% of a hygroscopic compound Contrainte (MPa) Déformation (% ) 15 days 7 days µm Déformation (% ) 17 I.Bétremieux, C.Chambat, G.Delmas, Steel coat, 18th june 2012

18 Water-borne Acrylics film formation Temperature and Humidity : What impact on film formation? Acrylic dispersion MFFT=5 C applied at 23 C, 50%HR applied at 5 C, 70%HR applied at 23 C, 20%HR 500µm 500µm 500µm What impact of the film formation on properties? to be continued at the next Techno Push Seminar 18 I.Bétremieux, C.Chambat, G.Delmas, Steel coat, 18th june 2012

19 Necessary condition for a good film formation MFFT < Application T Tg of the polymer Low Tg (soft) Good film formation Good flexibility BUT Poor block resistance Low hardness develop t High Tg (hard) Use of coalescent Good film formation Good hardness devlopm t Medium block resistance BUT Poor flexibility Hardness development (but slow with non-voc coalescent) lower the MFFT Good coalescent -evaporates from the film as fast as possible (but VOC...) -easy to incorporate -compatible -low odour & low price 19 I.Bétremieux, C.Chambat, G.Delmas, Steel coat, 18th june 2012

20 Film formation nm HDSL Hard + coalescent coalesce ent Hard / Soft blend + old generation of Core-Shells flexible matrix = soft coalesced shells reinforced by nano-spherical organic fillers = hard coresregularly dispersed for stable optimal properties ti ime coalescent Loss of flexibility with time Heterogeneous film with randomly dispersed d hard and soft zones 20 I.Bétremieux, C.Chambat, G.Delmas, Steel coat, 18th june 2012

21 HDSL technology : Acrylic dispersion Very good film formation Low MFFT (<5 C) binders A HDSL product (MFFT=5 C) A competitor s product (MFFT=8 C) 1000µm 1000µm Stability of the MFFT with ageing Formulation with reduced amount (or no) coalescing solvents For the customer, it allows the use of other solvents possible open time extenders, 21 I.Bétremieux, C.Chambat, G.Delmas, Steel coat, 18th june 2012

22 This presentation is the result of Arkema Coating Resins last developements. QUESTIONS? 22 I.Bétremieux, C.Chambat, G.Delmas, Steel coat, 18th june 2012