fundamentals of rheology; concepts and measurements
TRANSCRIPT
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(c) 2016 Elementis Specialties ACS 2012-Elementis Specialties, Inc.
Fundamentals of Rheology;
Concepts and Measurements
Mihai Polverejan, Ph.D.
PNW Society for Coatings
Technology
January, 2016
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Agenda
• Current WB Thickener Technologies
– Clays, HEC, ASE/HASE, NiSATs
• Rheological Concepts
– Viscosity, Shear Rate, Yield Point
• Evaluation Methods
– Rotational and Oscillatory Rheometry
• Examples
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Thickener Types for Waterborne Coatings
• Inorganic Thickeners
– Attapulgite / Bentonite clays / Hectorite clays
– Fumed Silica
• Cellulosic Thickeners
– HEC
– HMHEC
• Alkali-Responsive Thickeners
– ASE
– HASE
• Nonionic Synthetic Thickeners
– NiSAT- HEUR
– NiSAT - HMPE
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• Naturally occurring layered aluminum silicate
minerals
• Rarely used as a sole thickener
• There are two types of clays; Swelling and non-
Swelling
CLAYS
• Viscosity build
• Sag control
• Pigment suspension
• Metal flake control
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BENTONITE
HECTORITE
SMECTITE CLAY
SWELLING
KAOLIN
MICA
NON-SWELLING
CLAYS
Clay Minerals Family
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Gel-structure
Flocculation
Swelling
Hydration
Water
(Osmosis)
Deagglomeration
Water
Shear force
Smectite agglomerate
Na- Ions +
Clay Thickening Mechanism
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Silica Alumina Silica
8000 Å
10 Å
BENTONITE
Silica Magnesia
Silica
800 Å
10 Å
HECTORITE
Bentonite and Hectorite
Bentonite [Na-Al-Mg-Silicate]
Hectorite [Na-Mg-Li-Silicate]
H2O 13.7 12.5 Colour green cream
Platelet shape equidimensional elongated
Platelet size 0.8 x 0.8 x 0.001 µm 0.08 x 0.8 x 0.001 µm
Swelling ability 16 x 24 x
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Hectorite vs. Bentonite - Viscosity
1120
1920
3740
01000
2000
3000
4000
Bro
ok
fie
ld v
isco
sit
y,
cp
s
Bentonite clay BENTONE CT BENTONE MA (SD)
• Hectorite requires
more shear
• Hectorite has slower
hydration rate
• More efficient
• More effective:
• Syneresis control
• Suspension
stability
• Greater thixotropic
behavior
• Sag resistance
5% water gels
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Hectorite Clay Products
PRODUCT DESCRIPTION % ACTIVE MATTER
BENTONE® OC Unrefined hectorite clay 40 - 60
BENTONE® CT Unrefined hectorite clay 50
BENTONE® GS Refined hectorite clay 100
BENTONE® DE Refined hectorite clay
Hyperdispersible 100
BENTONE® MA Refined hectorite clay 100
BENTONE® LT Organically modified refined
hectorite 100
BENAQUA® 4000 Hectorite/polymer composite 100
BENTONE® DY-CE Organically modified clay 100
BENTONE® DH Organically modified hectorite 100
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NonSwelling Clay e.g.. Attagel 40,50
• Colloidal, inorganic mineral thickeners
• Optimum dispersion (high speed) is necessary to attain maximum viscosity – 3 -10 lbs./100 gal. added as last part of pigment
• 3 - 5 lbs. in semi gloss
• 3 - 7 lbs. in interior flat
– Should avoid excessive amount of dispersants
physical appearance micronized powders
pH 7.5 - 9.5
average particle size (microns) 0.1
color light cream
bulking value (gal/lbs.) 0.0507
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SILICAS
• Advantages – low cost
– provides settling resistance
– provides sag resistance
– Imparts thixotropy
• Disadvantages – pH sensitive
– powder (low density)
– decreases gloss
– cannot be used as sole thickener
• Commonly occurring
mineral
• forms loosely-woven lattice-
like network by hydrogen
bonding between particles
– network is stable at rest
– network is disrupted by
the application of an
applied stress or force,
but rebuilds when stress
is removed
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• naturally-occurring polysaccharide
• insoluble in water
• hydroxyl groups hinder solubility by promoting hydrogen bonding
- results in highly ordered crystalline structure
Structure of Cellulose
2OH 2OH
anhydrous ring
Hydroxy Ethyl Cellulose - HEC
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Cellulose Ether Thickeners
Advantages vs. Disadvantages
• Advantages
– reasonable properties for most paints as a single thickener
– provides good resistance to sagging and some settling and syneresis control
• Disadvantages
– increase probability of flocculation and lower gloss
– reduces washability
– lower film builds
– promotes roller spatter
– prone to microbial attack
• Solution viscosity increases
when HEC is dissolved in
water or other aqueous system
– polymer chains become
uncoiled and hydrated
– entanglement of hydrated
polymer chains in solution
– proportional to the polymer
chain length and polymer
molecular weight
13
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• Thicken through volume exclusion
– hydrophilic backbone tends to associate with the
surrounding water molecules
• Viscosity dependent upon the molecular weight (chain
length) and nature of the polymer :
• linear
• branched
• cross-linked
Modified Acrylics - ASE
Non-Associative: Alkali Soluble Emulsions
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OH-
pH > 7
COOH
COOH COOH COOR COOH
COOH COOH COOR
COOR COO-
COO- COO-
COO- COO-
COO- COOR
ester group
carboxylate anion
COOR
COO -
ASE Thickening Mechanism
COOR COO-
COO- COO-
COO- COO-
COO- COOR
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Alkali Swellable Emulsions Comparison with Cellulosics
• Advantages over Cellulosics
– Easier handling in production
– Not susceptible to microbial attack
– Lower cost
• Drawbacks
– More water sensitive
– Fairly pseudoplastic
– Poor resistance to roller spatter
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OH-
pH > 7
COOH
COOH COOH COOR COOH
COOH COOH COOR
COOR COO-
COO- COO-
COO- COO-
COO- COOR
hydrophobic group ester group
carboxylate anion
COOR
COO - binder
HASE Thickening Mechanism
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RHEOLATE ® ASE / HASE Series:
Rheological Additives – Acrylic/ Alkali Swellable
Alkali Swellable Emulsion
Hydrophobically Modified ASE
• High thickening efficiency:
• pH activated: 8.0 +
• VOC Free
• Easy to incorporate
• Use alone or with other thickeners
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RHEOLATE® Type VOC %
Active
Shear
Range
% Use
Level Applications
1 ASE none 30 Mid 0.3 -1.0 Across the board; industrial
& deco
125
150
ASE
HASE
none
none
30
30
Low-Mid
Low
0.3 -1.0
0.3 – 1.0
General Industrial
High efficiency low to mid-
shear- deco & industrial
175 HASE none 30 Mid 0.3 – 1.0 Mid-shear good leveling-
deco
420 HASE none 30 Mid 0.3 – 1.0 Across the board- Industrial
& deco
475 HASE none 30 Mid 0.3 – 1.0 Across the board; excellent
flow & leveling; good gloss
450 HASE none 30 Mid-High 0.3 – 1.0 High PVC systems- mainly
deco
RHEOLATE® ASE / HASE Series
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Associative Thickeners
• NiSAT = Non-Ionic Synthetic Associative Thickeners
(HEUR & HMPE)
• HEUR = Hydrophobically Modified Ethyleneoxide
Urethane
• HMPE = Hydrophobically Modified PolyEther
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Associative Thickener - Structure
Surfactant
Associative Thickener
Hydrophilic Tail
Hydrophilic
Backbone
21
hydrophobes
hydrophilic Polymer
Hydrophobic Head
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Associative Thickener – Surfactant:
Reason of Mechanism of Viscosity Loss
Once surfactant levels reach
critical levels they form their
own micelles which further
disrupt the AT mechanism as
the hydrophilic (water soluble)
tails cannot associate with
anything
Closed Micelle Structure
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Thickening Mechanism Associative Thickener Only
Hydrophobic
Particle
Hydrophobic
Particle
Hydrophobic
Particle
Fully Networked
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Network Totally
Disrupted
Hydrophobic
Particle
Hydrophobic
Particle
Hydrophobic
Particle
Mechanism of Viscosity Loss Associative Thickener With High Levels of Surfactant
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0
200
400
600
800
1000
1200
1400
1600
1800
0 0.2 0.4 0.6 0.8 1
Wt % Surfactant
Bro
okfi
eld
Vis
co
sit
y, cp
s
HLB = 3.6
HLB = 10.0
HLB = 12.4
Anionic
Effect of Surfactants
Ingredient effects on thickener response
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NiSAT (Associative) Thickeners
Superior Performance:
• pH independent
• ability to tailor rheology
• good leveling
• spatter resistance
• ease of use
• broad application
• newer technologies offer more resistance to
surfactant interactions
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Rheology Modifiers for Various Shear Rates
Bentone® EW, Bentone® DH (clays)
Rheolate® 666 Rheolate® 150
Rheolate® CVS-10, Rheolate® CVS-11
Rheolate® 310, Rheolate® 678
Rheolate® 475 (HASE)
Rheolate® 212, Rheolate® 644
Rheolate® 350, Rheolate® HX 6050
BROOKFIELD cPs or mPas STORMER
KU
Cone & plate ICI
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Rheological Additives - Why?
• Storage stability: Antisettling / Syneresis
• Application behavior
–Sag resistance
–Levelling
–Roller-spatter resistance
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Viscosity (η)
(Resistance to Flow) =
Shear Stress
Shear Rate
(t)
(g) .
Definition of Viscosity
Newton´s Law: τ= γxη .
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F [N] A= area [m²]
Shear Stress
t = shear stress = F/A [N/m²]
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F [N]
Shear Rate
g = shear rate = v/d [1/s]
d [m]
v = velocity [m/s]
.
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Assumption:
linear velocity (V) = 0.5 m/s
d = 0.2 mm
shear rate =
v
d = 0.5 m/s
0.0002 m
shear rate = 2500 1/s
d= 0.2 mm
V= 0.5 m/s
Shear Rate - Roller Application
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V= 5 s/m = 0.2 m/s
Film thickness = 50 µm
Shear Rate – Brush Application
0.2 m
5 x 10-5 m s = 4000 s-1 shear rate [1/s] =
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V= 0.1 m/s
Film thickness = 5 mm
shear rate [1/s] = 0.1 m = 20 s-1
0.005 m s
Shear Rate – Trowel Application
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Newtonian Viscosity is independent of shear rate
Viscosity profiles - Newtonian
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Viscosity profiles - Dilatant
dilatant Viscosity is increasing with increasing shear rate
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Viscosity profiles - Pseudoplastic
pseudoplastic Viscosity is decreasing with increasing shear rate
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Viscosity profiles - Thixotropic
thixotropic time dependent recovery after shear is removed
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Cone Plate (ICI) Viscometer
Rotor
Stator
Measures Absolute Viscosity
at constant shear of 10000 1/s
(Inclined plane varies film
thickness “d” at the same rate as
the velocity “V” is changing.
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Shear
rate varies from zero to
upper limit defined by
rotational speed & disk diameter
Spindle Disk Viscometer
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Measures “single point”
quasi-viscosity. Shear
rate varies from zero to
upper limit defined by
rotational speed & paddle length
Krebs Stormer Viscometer
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Flow curve - Emulsion paint
0.1
1
10
100
1,000
Pa·s
10-1
100
101
102
103
1/s
Shear Rate g.
RHEOLATE® 278, PVC 50% HEC, PVC 50%
Two paints with
very different flow
properties
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Viscosity measurement for coatings
ICI
Cone & Plate
Brookfield
Krebs Stormer
Rheometer
Oscillation
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Viscometer / Rheometer
Din Cylinder
Cone / Plate
50 µm gap
Plate / Plate
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processing
application
transportation storage
sag
levelling
settling
package viscosity brushing
rolling
spraying
post-application
Coating properties and shear rate
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0.001 0.01 0.1 1 10 100 1000 10000
0.01
0.1
1
10
100
1000
10000
100000
g shear rate (sec ) . -1
HEC/
CLAYS
ASE
HASE
HEUR
PEPO
vis
cosity
(Pa·s
)
Flow Profile Comparison
Equal Mid-Shear Viscosity
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Structural Recovery – viscosity vs. time
Preset of 3 steps:
low – high – low shear rate
Result:
time-dependent viscosity curve
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Time (s)
slow recovery
(Thixotropy)
fast recovery
V
isco
sity (
Pa
· s)
0.1 s-1 1000 s-1 0.1 s-1
Viscosity Recovery
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"Minimum shear stress required to induce flow"
Yield Value Viscosity
Pa Pa s
Honey 0 11.0
Ketchup 14 0.1
Mayonnaise 85 0.6
.
Yield Value
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Yield Value - Measurement
pseudoplastic flow behaviour with yield point
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Oscillation
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Viscometer / Rheometer
Rotation Oscillation
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ideal-viscous
e.g. mineral oil
viscoelastic
e.g. gum
ideal-elastic
e.g. steel
Viscoelasticity
Newton´s Law: τ= γxη Hooke´s Law: τ= G x γ .
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Viscoelasticity
A viscous material flows irreversibly when stress is applied.
An elastic material flows reversibly when stress is applied.
Viscoelastic materials have an intermediate behaviour.
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Oscillation Measurements
• An oscillating stress is applied to the sample
and the responding strain wave pattern is measured.
• The sample is stressed in a sinusoidal way.
Input
Output
δ
δ = 0° ideal elastic material
δ = 90° ideal viscous material
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(c) 2016 Elementis Specialties
Oscillation Experiments
G´
G´´
δ
G* G`` = loss or viscous modulus
G` = storage or elastic modulus
tan δ = G``/ G´ = damping (loss) factor
δ = 0° ideal elastic material
δ = 90° ideal viscous material
Viscous Viscoelastic Elastic
G``>> G` G``> G` G= G` G``< G` G``<< G`
Liquid-like structure Gel point Gel-like structure
tan δ>>1 tan δ>1 tan δ=1 tan δ<1 tan δ<<1
![Page 57: Fundamentals of Rheology; Concepts and Measurements](https://reader033.vdocuments.site/reader033/viewer/2022051315/627a5c8d53507f313048bc16/html5/thumbnails/57.jpg)
(c) 2016 Elementis Specialties
Amplitude Sweep D
efo
rmation
γ
Frequency Hz
Strain – Amplitude
The amplitude of oscillation is increased at constant frequency
to find the limit of the linear- viscoelastic LVE range
![Page 58: Fundamentals of Rheology; Concepts and Measurements](https://reader033.vdocuments.site/reader033/viewer/2022051315/627a5c8d53507f313048bc16/html5/thumbnails/58.jpg)
(c) 2016 Elementis Specialties
Amplitude Sweep
0.01
0.1
1
10
100
1000
10000
0.01 0.1 1 10 100
Shear Stress [Pa] or Deformation [%]
Mo
du
lus [
Pa]
G`
G``
LVE Range
Yield point (end of LVE range)
Flow (crossover)
point
![Page 59: Fundamentals of Rheology; Concepts and Measurements](https://reader033.vdocuments.site/reader033/viewer/2022051315/627a5c8d53507f313048bc16/html5/thumbnails/59.jpg)
(c) 2016 Elementis Specialties
Frequency Sweep D
efo
rmation
γ
Frequency Hz
Strain - Frequency
The frequency of the oscillation is increased at
constant amplitude to examine stability and long-
range interactions
![Page 60: Fundamentals of Rheology; Concepts and Measurements](https://reader033.vdocuments.site/reader033/viewer/2022051315/627a5c8d53507f313048bc16/html5/thumbnails/60.jpg)
(c) 2016 Elementis Specialties
0.1
1
10
100
1000
10000
0.001 0.01 0.1 1 10 100
Angular frequency [1/s]
Mo
du
lus [
Pa]
Frequency Sweep
G`
G``
![Page 61: Fundamentals of Rheology; Concepts and Measurements](https://reader033.vdocuments.site/reader033/viewer/2022051315/627a5c8d53507f313048bc16/html5/thumbnails/61.jpg)
(c) 2016 Elementis Specialties
Frequency Sweep
Long-term storage stability:
•Sedimentation, Settling
•Syneresis
•Appearance (consistency)
•Transport stability
![Page 62: Fundamentals of Rheology; Concepts and Measurements](https://reader033.vdocuments.site/reader033/viewer/2022051315/627a5c8d53507f313048bc16/html5/thumbnails/62.jpg)
(c) 2016 Elementis Specialties
Interpretation of results
Results are useful for relative comparisons
For good storage stability and sag control. Elasticity
should dominate after stresses are removed
For good levelling and flow. Viscosity should
dominate after stresses are removed
Data can be used to perfect a coating system
![Page 63: Fundamentals of Rheology; Concepts and Measurements](https://reader033.vdocuments.site/reader033/viewer/2022051315/627a5c8d53507f313048bc16/html5/thumbnails/63.jpg)
(c) 2016 Elementis Specialties
Viscoelasticity
initial after 5 minutes
salad
dressing
olive
oil
salad
dressing
olive
oil
![Page 64: Fundamentals of Rheology; Concepts and Measurements](https://reader033.vdocuments.site/reader033/viewer/2022051315/627a5c8d53507f313048bc16/html5/thumbnails/64.jpg)
(c) 2016 Elementis Specialties
Viscoelasticity - Frequency sweep
10-8
10-7
10-6
10-5
10-4
10-3
10-2
10-1
100
102
Pa
G'
G''
0.1 1 10 1001/s
Angular Frequency
G' Salad dressing G' Olive oil G'' Salad dressing G'' Olive oil
stable
unstable
practically no G ´ (structure)
![Page 65: Fundamentals of Rheology; Concepts and Measurements](https://reader033.vdocuments.site/reader033/viewer/2022051315/627a5c8d53507f313048bc16/html5/thumbnails/65.jpg)
(c) 2016 Elementis Specialties
Examples
![Page 66: Fundamentals of Rheology; Concepts and Measurements](https://reader033.vdocuments.site/reader033/viewer/2022051315/627a5c8d53507f313048bc16/html5/thumbnails/66.jpg)
(c) 2016 Elementis Specialties
Latex Paint
Test System:
- Latex paint pvc 50% based on acrylic binder (spatter and poor levelling).
Thickeners:
- Mid-range HEC (0.6% on total)
- Newtonian associative thickener RHEOLATE® 212 (0 – 2.0 % on total)
![Page 67: Fundamentals of Rheology; Concepts and Measurements](https://reader033.vdocuments.site/reader033/viewer/2022051315/627a5c8d53507f313048bc16/html5/thumbnails/67.jpg)
(c) 2016 Elementis Specialties
Flow Behaviour
0.1
1.0
10.0
100.0
1000.0
0.1 1 10 100 1000
Shear rate [1/s]
Vis
co
sit
y [
Pa
.s]
mid-range HEC thickener
RHEOLATE® 212 associative thickener
![Page 68: Fundamentals of Rheology; Concepts and Measurements](https://reader033.vdocuments.site/reader033/viewer/2022051315/627a5c8d53507f313048bc16/html5/thumbnails/68.jpg)
(c) 2016 Elementis Specialties
Latex Paint - Flow Behaviour
10-1
100
101
102
103
Pa·s
10-1
100
101
102
103
1/s
Shear Rate .
blank
+ 0.5% RHEOLATE® 212
+ 1.0% RHEOLATE® 212
+ 1.5% RHEOLATE® 212
+ 2.0% RHEOLATE® 212
increased mid
and high shear viscosity
![Page 69: Fundamentals of Rheology; Concepts and Measurements](https://reader033.vdocuments.site/reader033/viewer/2022051315/627a5c8d53507f313048bc16/html5/thumbnails/69.jpg)
(c) 2016 Elementis Specialties
Latex Paint – Frequency Sweep e
lastic
ity d
ecre
ases
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5
0.55
0.6
tan( )
0.1 1 10 100rad/s
Angular Frequency
tan( ) blank
tan( ) 0.5% RHEOLATE® 212
tan( ) 1.0% RHEOLATE® 212
tan( ) 1.5% RHEOLATE® 212
tan( ) 2.0% RHEOLATE® 212
tan(δ)=G”/G’
![Page 70: Fundamentals of Rheology; Concepts and Measurements](https://reader033.vdocuments.site/reader033/viewer/2022051315/627a5c8d53507f313048bc16/html5/thumbnails/70.jpg)
(c) 2016 Elementis Specialties
Latex Paint - Brush-out
blank (0) + 0.5% RHEOLATE 212 (2) + 1.0% RHEOLATE 212 (3)
+ 1.5% RHEOLATE 212 (4) + 2.0% RHEOLATE 212 (5)
ranking: 0= poor; 5= excellent
![Page 71: Fundamentals of Rheology; Concepts and Measurements](https://reader033.vdocuments.site/reader033/viewer/2022051315/627a5c8d53507f313048bc16/html5/thumbnails/71.jpg)
(c) 2016 Elementis Specialties
Latex Paint - Roller Spatter Resistance
ranking: 0= poor; 5= excellent
blank (0) + 0.5% RHEOLATE 212 (2) + 1.0% RHEOLATE 212 (3)
+ 1.5% RHEOLATE 212 (4) + 2.0% RHEOLATE 212 (4-5)
![Page 72: Fundamentals of Rheology; Concepts and Measurements](https://reader033.vdocuments.site/reader033/viewer/2022051315/627a5c8d53507f313048bc16/html5/thumbnails/72.jpg)
(c) 2016 Elementis Specialties
Summary
Formulation of the RHEOLATE 212 associative thickener into a standard latex paint improves: • Mid and high-shear viscosity (film build and brush drag) • Brush-out levelling • Roller-spatter resistance - by decreasing the elasticity of the latex paint
![Page 73: Fundamentals of Rheology; Concepts and Measurements](https://reader033.vdocuments.site/reader033/viewer/2022051315/627a5c8d53507f313048bc16/html5/thumbnails/73.jpg)
(c) 2016 Elementis Specialties
Epoxy Coating
• Evaluate various rheological additives in an epoxy
coating Part A to improve syneresis and settling
characteristics.
Level
RHEOLATE 288 1%
RHEOLATE 288 3%
RHEOLATE 299 1%
BENTONE GS 1%
BENTONE GS 2%
BENTONE LT 0.5%
BENTONE LT 1%
![Page 74: Fundamentals of Rheology; Concepts and Measurements](https://reader033.vdocuments.site/reader033/viewer/2022051315/627a5c8d53507f313048bc16/html5/thumbnails/74.jpg)
(c) 2016 Elementis Specialties
Rheological Profile-Flow
Performed flow curves on the Anton Paar MCR 301 rheometer using the 50 mm parallel plate configuration at 25°C
with a 1 mm gap. A logarithmic ramp from 0.1 to 100 s-1 shear rate.
1
10
100
Pa·s
0.1 1 10 100 1,0001/s
Shear Rate .
CTRL Rh 299 1% Rh 288 1% Rh 288 3%
![Page 75: Fundamentals of Rheology; Concepts and Measurements](https://reader033.vdocuments.site/reader033/viewer/2022051315/627a5c8d53507f313048bc16/html5/thumbnails/75.jpg)
(c) 2016 Elementis Specialties
Rheological Profile-Flow
Performed flow curves on the Anton Paar MCR 301 rheometer using the 50 mm parallel plate configuration at 25°C
with a 1 mm gap. A logarithmic ramp from 0.1 to 100 s-1 shear rate.
1
10
100
Pa·s
0.1 1 10 100 1,0001/s
Shear Rate .
CTRL Bentone GS 1% Bentone GS 2% Bentone LT 1% Bentone LT 0.5%
![Page 76: Fundamentals of Rheology; Concepts and Measurements](https://reader033.vdocuments.site/reader033/viewer/2022051315/627a5c8d53507f313048bc16/html5/thumbnails/76.jpg)
(c) 2016 Elementis Specialties
Rheological Profiles-Frequency Sweep
tan(δ)=G’’/G’
100
101
102
103
tan( )
0.1 1 10 1001/s
Angular Frequency
CTRL RH 299 1% Rh 288%
![Page 77: Fundamentals of Rheology; Concepts and Measurements](https://reader033.vdocuments.site/reader033/viewer/2022051315/627a5c8d53507f313048bc16/html5/thumbnails/77.jpg)
(c) 2016 Elementis Specialties
Rheological Profiles-Frequency Sweep
tan(δ)=G’’/G’
100
101
102
103
tan( )
0.1 1 10 1001/s
Angular Frequency
CTRL Bentone GS 2% Bentone LT 0.5% Bentone LT 1%
![Page 78: Fundamentals of Rheology; Concepts and Measurements](https://reader033.vdocuments.site/reader033/viewer/2022051315/627a5c8d53507f313048bc16/html5/thumbnails/78.jpg)
(c) 2016 Elementis Specialties
Heat Aging 140F, 7 Days
0.08% GS 0.16% GS
Level Syneresis (mm)
Base Part A 5
RHEOLATE 288 1% 20
RHEOLATE 288 3% 22
RHEOLATE 299 1% 20
BENTONE GS 1% 1
BENTONE GS 2% <1
BENTONE LT 0.5% <1
BENTONE LT 1% <1
![Page 79: Fundamentals of Rheology; Concepts and Measurements](https://reader033.vdocuments.site/reader033/viewer/2022051315/627a5c8d53507f313048bc16/html5/thumbnails/79.jpg)
(c) 2016 Elementis Specialties
Summary
• BENTONE® GS and LT:
Improved syneresis/settling (elastic) properties of the
epoxy coating without majorly impacting the overall
viscosity.
![Page 80: Fundamentals of Rheology; Concepts and Measurements](https://reader033.vdocuments.site/reader033/viewer/2022051315/627a5c8d53507f313048bc16/html5/thumbnails/80.jpg)
(c) 2016 Elementis Specialties
Yield Point and Sag Correlation
Large Format Tile
(8 lb./sq. feet)
Mortar
Yield Point
(Pa)
Sag (mm)
3 min./10 min.
HEC 27 30/32
0.4% Bentone MA
0.1% Rh 101 61 8/17
0.25% Bentone MA
0.25% Rh 101 109 2/3
The Yield Point is determined using Amplitude Sweep
![Page 81: Fundamentals of Rheology; Concepts and Measurements](https://reader033.vdocuments.site/reader033/viewer/2022051315/627a5c8d53507f313048bc16/html5/thumbnails/81.jpg)
(c) 2016 Elementis Specialties
Thixotropy- Structural Decomposition
and Regeneration (ORO)
REST REST HIGH
SHEAR
Rotation
ỳ
Oscillation
γ, ω
Oscillation
γ, ω
t1 t3 t2 t0
1 2 3
1. Structure at rest
2. Structural decomposition
3. Structural regeneration
![Page 82: Fundamentals of Rheology; Concepts and Measurements](https://reader033.vdocuments.site/reader033/viewer/2022051315/627a5c8d53507f313048bc16/html5/thumbnails/82.jpg)
(c) 2016 Elementis Specialties
Oscillation-Rotation-Oscillation Study
Eggshell white acrylic based paint
Evaluate various mid-shear thickeners to
improve the sag resistance (the paint originally
sags after spray application).
![Page 83: Fundamentals of Rheology; Concepts and Measurements](https://reader033.vdocuments.site/reader033/viewer/2022051315/627a5c8d53507f313048bc16/html5/thumbnails/83.jpg)
(c) 2016 Elementis Specialties
Oscillation-Rotation-Oscillation Study
101
102
Pa
G''
G'
100
101
100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400s
Time t
CTRL KU-1 KU-3
Sample Crossover
time (s)
CTRL 50
KU-1 25
KU-3 <5
Eggshell white acrylic based paint
Rotational
Interval
![Page 84: Fundamentals of Rheology; Concepts and Measurements](https://reader033.vdocuments.site/reader033/viewer/2022051315/627a5c8d53507f313048bc16/html5/thumbnails/84.jpg)
(c) 2016 Elementis Specialties
For further information please refer to
www.Elementis-Specialties.com
© Copyright 2016, Elementis Specialties, Inc. All rights reserved. Copying and/or downloading of this document or information therein for republication is not
allowed unless prior written agreement is obtained from Elementis Specialties, Inc.
The information in this publication is, to the best of our knowledge, true and accurate, but since the conditions of use are beyond our control, no warranty is given or
to be implied in respect of such information. In every case, caution must be exercised to avoid violation or infringement of statutory obligations and any rights
belonging to a third party. We are, at all time, willing to study customers’ specific outlets involving our products in order to enable their most effective use.
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