2. Newton’s Two Plate Model
Force (F)
Area (A)
Velocity (v)
Distance (d)
τ (Pa) = shear stress
(force / area)
D(1/s) = shear rate
(velocity / distance)
η= τ / D η = viscosity (Pa·s)
(resistance against flow)
07/03/12, Page 2, Rheology Additives
3. Viscosity Curve
viscosity η
newtonian: η = const.
pseudoplastic flow: η = f (D)
(shear thinning)
shear rate D
07/03/12, Page 3, Rheology Additives
4. Thixotropy Curve
viscosity η is time dependent:
Viscosity η
D = const. D=0 viscosity η
Time t shear rate D
07/03/12, Page 4, Rheology Additives
5. Viscosity Profile
Viscosity (Pa·s)
η
100 Storage Transportation Production
Leveling Stirring Application
10 Sagging
Settling
Rotational viscometer
Brookfield
1 Flow cup 4 mm ICI
cone/plate
0,1
0,001 0,01 0,1 1 10 100 1000 10000
shear rate D (1/s)
07/03/12, Page 5, Rheology Additives
6. Liquid Rheology Additives: Differentiation
Polar systems
BYK-411 BYK-410 BYK-420 BYK-431 BYK-430 BYK-425
Non-polar systems
Thixotropic flow : Pseudoplastic flow :
• Slower structure recovery • Faster structure recovery
after shear after shear
good for leveling and air release excellent sag resistance
• Anti-settling • Anti-settling
• Pronounced shear-thinning
07/03/12, Page 6, Rheology Additives
7. BYK-410, BYK-411, BYK-420:
Thixotropy Additives Based on Modified Urea
BYK-410
BYK-411
BYK-420
Urea groups
Modifying groups :
High polarity Medium polarity Low polarity
07/03/12, Page 7, Rheology Additives
8. Mode of Action
Incorporation
under stirring Active substance
precipitates in form
of micro crystals
Structure formation
Network build up via hydrogen bondings
Result: Strong thixotropic flow behavior
07/03/12, Page 8, Rheology Additives
9. Structure Formation Through Hydrogen Bonding
O
C
N
N
H H
O
C
N Hydrogen bonding via urea groups
N
H H
07/03/12, Page 9, Rheology Additives
10. BYK-410: Efficiency Depends on Polarity of System
too non-polar Compatible too polar
White spirits Diacetone alcohol Isopropanol
Xylene Butanol Water
Isobutanol
Butylglycol
Butylacetate
Propylenglycol-
Monomethylether
Suitable solvent mixtures:
Xylene / n-Butanol = 80 / 20
Butyl acetate / Dowanol PM = 75 / 25
07/03/12, Page 10, Rheology Additives
11. BYK-410: Compatibility Adjustment
Compatibility
improvement
1. Addition of BYK-410 to the possible using
non-pigmented formulation solvents with
(homogeneous mixing) suitable
polarity
2. Compatibility test
visual judgement of compatibility Particles /
(particles / seeds) and seeds visible
rheological effect
Compatibility
is acceptable,
No particles / no seeds and
no formulation
rheological effect
changes are
necessary
07/03/12, Page 11, Rheology Additives
12. BYK-411: Rheology Control in Low Polar Resins
• No effect in pure solvents,
requires resin
• Structure formation via hydrogen
bonding and associative
interactions
Control 1 % BYK-411
07/03/12, Page 12, Rheology Additives
13. BYK-411: Compatibility Test
Resin + BYK-411
homogenize
Compatible Incompatibility
+ +
effective no effect
Resin is
Resin is not suitable !
suitable ! Improvement is
not possible !
07/03/12, Page 13, Rheology Additives
14. BYK-420: Rheology Control in Aqueous Systems
Homogenous, rapid incorporation: Inhomogenoues incorporation:
excellent thickening effect no thickening effect
homogenoues, no particles inhomogenoues, particles
07/03/12, Page 14, Rheology Additives
15. BYK-420 in Aqueous Effect Pigment Slurry
1. Water 50,0 – 68,7
2. Co-solvents 5,0 – 10,0
(e.g., glycols and glycol ethers)
• DISPERBYK-190 or
DISPERBYK-192 1,0 – 3,0
• Effect pigment 25,0 – 35,0
5. BYK-420 0,3 – 1,0
(incorporation under stirring)
07/03/12, Page 15, Rheology Additives
16. BYK-420: Effective Thickening of Pure Water
150
BYK-420 1% active loading
Acrylate thickener 1% active loading
Pa s
Synthetic clay 1% active loading
100 Natural clay 2% active loading
Fumed silica 5% active loading
Viscosity
50
0
0,05 0,1 0,2 0,5 1 2 5 10
shear rate D(1/s)
07/03/12, Page 16, Rheology Additives
17. BYK-420: Compatibility Test
Compatibility
improvement
1. Addition of BYK-420 to the possible using
non-pigmented formulation co-solvents and
(homogeneous mixing) wetting/dispersing
additives
2. Compatibility test
visual judgement of compatibility Particles /
(particles / seeds) and seeds visible
rheological effect
Compatibility
is acceptable,
No particles / no seeds and
no formulation
rheological effect
changes are
necessary
07/03/12, Page 17, Rheology Additives
18. Liquid Rheology Additives: Differentiation
Polar systems
BYK-411 BYK-410 BYK-420 BYK-431 BYK-430 BYK-425
Non-polar systems
Thixotropic flow : Pseudoplastic flow :
• Slower structure recovery • Faster structure recovery
after shear after shear
good for leveling and air release excellent sag resistance
• Anti-settling • Anti-settling
• Pronounced shear-thinning
07/03/12, Page 18, Rheology Additives
19. BYK-425: Pseudoplastic Flow in Aqueous Systems
Conventional
PU thickener
Urea modification
BYK-425
• Urea modified polyurethane
• dissolved in polypropylene glycol
urea hydrophobic
groups groups
07/03/12, Page 19, Rheology Additives
21. BYK-425: No Effect in Pure Water
BYK-420 Dosage:
2 % active substance
viscosity (Pa*s)
BYK-425
shear rate (1/s)
07/03/12, Page 21, Rheology Additives
23. BYK-425: Advantages
• Thickener with broad universal compatibility in various aqueous binder systems
• Post addition possible
• Easy to handle
- no pH adjustments necessary
- can be diluted with water
• No negative influence on film properties
• VOC-free, APEO-free
• No higher costs compared to common thickeners
• Dependant on system two to three times more effective
07/03/12, Page 23, Rheology Additives
24. BYK-430 / BYK-431 Chemical Structure
High molecular weight urea modified polyamides
BYK-430
BYK-431
Urea groups
Polyamide
Compatibility enhancing structures (alkyl, polyether)
07/03/12, Page 24, Rheology Additives
27. BYK-430 / BYK-431: Application Areas
Non-polar systems Polar systems
BYK-430
BYK-431
ol
EK
K
ne
er
e
G
l
i c te
r
ol
ho
IB
an
at
te
0
l
at
le
co
a
M
ar
an
10
et
M
Es
i b cet
co
op
W
Xy
op
ly
ac
ut
so
al
pr
lg
la
B
Is
l
py
es
y
y
as
ne
xy
n-
ut
ut
lv
ro
ho
to
B
B
So
D
p
ce
et
xy
M
ia
ho
D
et
BYK-431: M BYK-430:
- Architectural paints -Recommended for solvent-borne high
- Refinish coatings and primers build systems
- Protective / marine coatings
- Industrial coatings
e.g. : e.g. :
- Alkyds, polyesters - 2-pack epoxy top coat
- Thermoplastic acrylates - 2-pack coal tar epoxy
- Epoxy primers
- 2-pack polyurethanes - 2-pack polyurethanes
07/03/12, Page 27, Rheology Additives
31. BYK-430 / BYK-431: Advantages
• Handling
- Liquid, easy to handle and processing
- Post addition possible
- No deagglomeration required
- No controlled cool down phase after production required
- Activation temperature below 50°C
- No seeding tendency during storage
• Application
- Excellent sag control
- Ideal anti-settling properties even at higher temperatures
- No intercoat adhesion problems (compared to other polyamides)
07/03/12, Page 31, Rheology Additives
32. ANTI-TERRA®, BYK®, BYK®-DYNWET®, BYK®-SILCLEAN®,
BYKANOL®, BYKETOL®, BYKOPLAST®, BYKUMEN®, DISPERBYK®,
DISPERPLAST®, LACTIMON®, NANOBYK®, SILBYK® and
VISCOBYK® are registered trademarks of BYK-Chemie.
AQUACER®, AQUAFLOUR®, AQUAMAT®, CERACOL®, CERAFAK®,
CERAFLOUR®, CERAMAT®, CERATIX® and MINERPOL® are
registered trademarks of BYK-Cera.
This information is given to the best of our knowledge. Because of the
multitude of formulations, production, and application conditions, all the
above mentioned statements have to be adjusted to the circumstances of
the processor.
No liabilities, including those for patent rights, can be derived from this
fact for individual cases.
07/03/12, Page 32, Rheology Additives
