Introduction to film formation for SB & WB technologiessteelcoatproject.com/wp-content/uploads/2017/05/SteelCoat_Webinar...SC 50SC = 50-100% Need to be ... of an homogeneous crosslinked

Introduction to film formation for SB & WB technologies

Solvent Borne

Key Characteristics of SB technologies

L t di l l i ht l di l dLow to medium molecular weight polymers dissolved in various solvents (Mw = 5000-50000)

SC 50 100%SC = 50-100%

Need to be crosslinked to fully develop final properties

3 I.Bétremieux, C.Chambat, G.Delmas, Steel coat, 18th june 2012

O2, Isocyanate, Melamine

Key properties of Solvenborne technologiesLiquid form

Ease of formulation

INGREDIENTS Weight Volume Function Supplier

1 SYNOLAC 4013 WD 85 High solid long oil alkyd resin ARKEMA2 ANTI TERRA 206 Dispersing Agent BYK CHEMIE3 TIOXIDE TR 92 Pigment : Titanium dioxide HUNSTMAN

Addition under stirring 4 SYNOLAC 4013 WD 85 High solid long oil alkyd resin ARKEMA

300,76 337,942,44 2,60

Disperse at high speed

347,37 86,84

188,79 212,12

Ease of applicationRheology newtonian or thixotropicOpen time directly linked to the solvent

g g y5 OCTA SOLIGEN 69 Driers OMG Group6 OCTA SOLIGEN CALCIUM 10 basique Drier OMG Group7 BORCHI NOX M 2 Anti-skinning agent OMG Group

Viscosity adjustment 8 SPIRDANE D40 Solvent TOTAL

Total

4,17 3,834,17 4,252,85 3,10

149,45 194,09

1000,00 844,76

Dry film Contrainte (MPa)323 01 1010 2.5

323-01 14j à TA +14j à 50°C 323-04 14j à TA +14j à 50°C 323-05 14j à TA +14j à 50°C 323-06 14j à TA +14j à 50°C 323-011 14j à TA+14j à 50°Cy

Bind all the formulation together

Adhesion

A (Gl )10

12

14

16

18

20

22

24323-01

323-04

323-05

323-06

323-011

106

107

108

109

10

1.0

1.5

2.0

2.5

E' (

)

[P

a]

tan_delta ()

[ ]

Aspect (Gloss)

Durability 0

2

4

6

8

0 10 20 30 40 50 60 70

Déformation (%)

-80.0 -20.0 40.0 100.0 160.0103

104

105

0.0

0.5

Temp [°C]

Typical properties


of an homogeneous crosslinked polymer

Solvent-borne alkyds film formation

100

Solvent-borne alkyds

alkyd = “pre-polymer” soluble in the solvent

= Continuous process

10

y p p yI - Evaporation of the solventsolvent evaporates slowly

viscosity increases gradually10

ate

(Hz)

II - Siccativation O2 « reacts » with the C in α of the C=C

tri-dimensional network Tg increase1

spec

kle

ra g

0,1Long open time :possible to solubilise the non siccativated “pre-polymer”

New chemical bonds between FA

0,010 10 20 30 40 50 60 70 80

time (min)Diffusion Wave Spectroscopy of the film formation of an solventborne alkyd

pre polymer


y(made for Cray Valley on Horus®, Formulaction, Alice Brun)

Water Borne

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% < SC < 68%

30 nm < Ø <700nm

Viscosity : Solid content, particle size, interaction betweenViscosity : Solid content, particle size, interaction between particlesCan be crosslinked but can also be used without crosslinking (thermoplastic)


(thermoplastic)

Key properties of WB technologies

Liquid form

Low viscosity although high

Ref: DECO-CC-11-349-04

INGREDIENTS Weight Volume Function Supplier

1 CRAYMUL® 2785 acrylic dispersion ARKEMAadd the millbase

2 WATER solvent3 ACTICIDE MBS biocide THOR CHEMIE4 BYK 028 Defoamer BYK5 COADISTM 123 K dispersing agent COATEX

628,00 592,45

52,00 52,002,00 1,941,50 1,44

10 00 9 26Low viscosity although high molecular weight polymer

Very low VOC (< 2000ppm)

Formulation for final

5 COADISTM 123 K dispersing agent COATEX6 TIONA 595 TiO2 CRISTAL GLOBAL

Add under stirring 7 WATER solvent

adjust pH>8,5 8 NaOH, 20% 9 COAPURTM 2025 PU associative thickener COATEX

10 COAPURTM 830 W PU associative thickener COATEX11 FOAMSTAR A 38 Defoamer COGNIS

Total

10,00 9,26210,00 51,22

53,87 53,87

7,09 5,8130,36 29,204,18 3,951,00 1,05

1000,00 802,19

application more complex

Application conditions more controlled

PAINT CHARACTERISTICS : DRY FILM CHARACTERISTICS :

Density (g/cm³) Solids Density (g/cm³)Weight % Solids (%) PVC (additive included) (%)Volume % Solids (%) PVC (minus additive) (%)VOC (water incl.) (g/L)

1,25 1,6749,40 17,2936,93 18,01

0

Dried film

Bind all the formulation together

Adhesion

Mechanical properties, durability, infinity of possibilities 105

106

107

108

109

1010

2.0

3.0

)a]

tan(δ) ( [ ]

Tα= 54°C20 MPa

Tensile Strength

possibilities

Can’t be high gloss

-50.0 0.0 50.0 100.0 150.0 200.0100

101

102

103

104

10

0.0

1.0

Temp [°C]

E' (

[Pa

)]

Tα1= 10°CTα2 = 111°C

Warning: Overlay units don't match TimeElongation % 1000


Temp [°C]Warning: Overlay units don t match, TimeElongation % 1000

Water-borne Acrylics film formation

10

Water-borne AcrylicsThe polymer is not soluble in water : solid particles dispersed in water (surfactant)

I : Evaporation of water

= Discontinuous process

1

I : Evaporation of water

II : Coalescence : closed packed particles

0 1rate

(Hz)

0,1

spec

kle

r

III : Particles fusion

0,01

IV : Inter-diffusionShort open time :impossible to solubilise polymer

0,0010 10 20 30 40 50 60 70 80

time (min)Diffusion Wave Spectroscopy of the film formation of an acrylic dispersion


(made for Cray Valley on Horus®, Formulaction, Alice Brun)

Water-borne Acrylics film formationWater-borne Acrylics : A 4 step mechanism - view from the top

4 hours30 min 4 hours30 min

400 nm

24 hours11 hours


Water-borne Acrylics film formationWater-borne Acrylics : A 4 step mechanism - view from the front

IIIIorII

I

At the surface II - Coalescence : closed packed particles


At the surface, II Coalescence : closed packed particlesDeeper in the wet film : I - Evaporation of water

Water-borne Acrylics film formationWater-borne Acrylics : A 4 step mechanism - view from the front

IIIor

IIII

II

I

Film formation steps take place at the same time depending where you observe the filmFilm formation requires energy for the evaporation of the water


Film formation requires energy for the evaporation of the waterit takes it from the substratethere is a temperature gradient in the wet film

Water-borne Acrylics film formationIV - Interdiffusion

IV Coalescence only if T° > MFFTIV- Coalescence only if T > MFFTInter-diffusion (autohesion) of polymer chains from one particle to the other

Formation of a tri-dimensional networkEntanglement and/or self-crosslinking

T° > MFFTT > MFFT

autohesion zone : some nanometers


concerns ONLY polymer chains at the surface of the particle

Water-borne Acrylics film formationCritical parameters & their impact on film formation

Water evaporation rate (temperature / humidity)p ( p y)- the more slowly the evaporation, the better the film formation

Particle size- capillary forces :

the smaller the particles, the lower the MFFT

Ch d th ti l (i iti t f t t t li ti b )Charges around the particles (initiators, surfactant, neutralisation base)- electrostatic repulsions :

the lower the charges, the easier the film formation

Mobility of the polymer chains at the surface of the particle- Molecular weightg

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


Water-borne Acrylics film formationExample of film formation

Two Acrylic dispersions with same MFFTs

Atomic Force Microscopy, emulsions dried 1 day at 5°C / 70% HRCRAYMUL 2138 Competitive low MFFT acrylic P

Low Mw of surface oligomers



Macroscopic aspect : correctMicroscopic aspect : deep cracks

“old generation”of Core-Shells

500µm

the film is not correctly formed Why ?To be continued…

Macroscopic aspect : « opaque » : mud -crackingMicroscopic aspect : cracks at the surfaceMicroscopic aspect : cracks at the surface

the film is formed but not perfectly at its surface500µm

+1% of a hygroscopic compound

Macroscopic aspect : perfectMicroscopic aspect : perfect

Water evaporates more slowly

Microscopic aspect : perfect

the film is formed through its whole thickness

500µm


What impact of the film formation on properties ?

p y500µm

Film formation and mechanical properties

3

4

5

6Contrainte (MPa)

0

1

2

0 20 40 60 80 100 120 140 160 180 200

Déformation (%)

500µmDéformation (%)

4

5

6

7

C o n tra in te (M P a )

0

1

2

3

4

0 2 0 4 0 6 0 8 0 1 0 0 1 2 0 1 4 0 1 6 0 1 8 0 2 0 0 2 2 0 2 4 0 2 6 0

500µm0 2 0 4 0 6 0 8 0 1 0 0 1 2 0 1 4 0 1 6 0 1 8 0 2 0 0 2 2 0 2 4 0 2 6 0

D é fo rm a t io n (% )

6

7

C o n tra in te (M P a )

7 days15 days

+1% of a hygroscopic compound

1

2

3

4

5

500µm


00 2 0 4 0 6 0 8 0 1 0 0 1 2 0 1 4 0 1 6 0 1 8 0 2 0 0 2 2 0 2 4 0 2 6 0 2 8 0

D é fo rm a tio n (% )

500µm


Temperature and Humidity : What impact on film formation ?

Acrylic dispersion MFFT=5°C

p

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


to be continued at the next Techno Push Seminar…

Necessary condition for a good film formation

MFFT < Application T°

Tg of the polymer

Low Tg (soft)Good film formation

High Tg (hard)Use of coalescent lower the MFFT

BUT

Good film formationGood flexibility

Use of coalescent lower the MFFT

Good film formationGood hardness devlopmt

Good coalescent

-evaporates from the film as

Poor block resistanceLow hardness developt

Good hardness devlopmt

Medium block resistance

BUT

pfast as possible (but VOC...)-easy to incorporate-compatible l d l

Poor flexibilityHardness development

(but slow with non VOC coalescent)

-low odour & low price


(but slow with non-VOC coalescent)

Film formationHDSL Hard / Soft blend

+

“old generation” of Core-Shells

00 n

mHard + coalescent

ent

10

coal

esce

ime

coalescent Heterogeneous film with d l di d h d

“ flexible matrix ” = soft coalesced shellsti randomly dispersed hard

and soft zonesreinforced by

“ nano-spherical organic fillers ”= hard coresregularly dispersedfor stable optimal properties


Loss of flexibility with timefor stable optimal properties

HDSL technology : Acrylic dispersionVery good film formation

Low MFFT (<5 C) binders

A HDSLHDSL product (MFFT=5 C) A competitor’s product (MFFT=8 C)( )

Stability of the MFFT with ageing

1000µm 1000µm

Stability of the MFFT with ageingFormulation with reduced amount (or no) coalescing solvents

For the customer, it allows the use of other solvents possibleti t d


open time extenders, …

This presentation is the result of Arkema Coating Resins

last developements.

QUESTIONS ?QUESTIONS ?


Documents

Introduction to film formation for SB & WB technologiessteelcoatproject.com/wp-content/uploads/2017/05/SteelCoat_Webinar...SC 50SC = 50-100% Need to be ... of an homogeneous crosslinked