Post on 13-Jul-2018
Renewable and Biodegradable Monomers for Adhesive Materials
Steve Severtson
University of Minnesota
Pressure Sensitive Adhesives
Release Liner
Inks
Paper Facestock
Pressure Sensitive Adhesive
Research Motivation
Renewable
Resources
Fossil
Fuels
Landfill
Pressure Sensitive Adhesive
Polymers
Sustainable
Life-Cycle
Non-Sustainable
Life-Cycle Unstable
Price &
Availability
$0.00
$0.25
$0.50
$0.75
$1.00
$1.25
$1.50
$1.75
US
Do
llars
(p
er
po
un
d)
Date
Acrylic acid
petroleum derived
materials
materials derived from
biorenewables
“Bridge Technology”
Research Objectives
Modifying existing commercial technologies by incorporating biomass without sacrificing performance or increasing costs.
PSA Market & Composition • Soft Monomers
– Majority of polymer – Allow PSA to flow and wet surfaces – Range: Tg ≤ -40 °C
• Hard Monomers – Provide adhesive and cohesive strength – Range: Tg ≥ 30 °C
• Functional Monomers – Charged groups for stability – Means of crosslinking
PSA Market Share
Tackifier Emulsifier Wetting Agent
Defoamer
Rheology Modifier
Polymer
Composition of Typical Water-Based PSA
$40.6 Billion Total 12.1 Million Tons
Water-based $20.3 Billion
Hotmelt $5.7 Billion
Reactive $6.1 Billion
Solvent $6.5 Billion
Other $2.0 Billion
DPNA International, Inc.
Research Outline • Soft Monomers
– Majority of polymer – Allow PSA to flow and wet surfaces – Range: Tg ≤ -40 °C
• Hard Monomers – Provide adhesive and cohesive strength – Range: Tg ≥ 30 °C
• Functional Monomers – Charged groups for stability – Means of crosslinking
Renewable Resources Tackifier
Emulsifier Wetting Agent
Defoamer
Rheology Modifier
Polymer
Composition of Hybrid Water-Based PSA
2-Ethylhexyl acrylate
n-Butyl acrylate
Copolymerization of Biomass Processing Byproducts with Acrylic Monomers
Molecular Weight ↑ Biodegradability ↓
No Degradation
Degradability of LMW PSA properties of HMW
Bio-Degradation
Ground
Easily degradable “links” Small mass fraction => Small effect on PSA properties
Bio-degradable small chains => Entire polymer is compostable
Enoki, Doi, Iwata. Biomacromol. 2003, 4, 314 Kawai. Appl. Microbiol. Biotechnol. 1993, 39, 382 Haines, Alexander. Appl. Microbiol. 1974, 28, 1084
Weak Link Approach
Adhesive Polymer Containing Acrylated Biomass Macromonomers Copolymer with Conventional Backbone
High Percentage of Biomass Additives from
Renewable Resources
Ground
Additives Degrade
Biomass Degrades
Backbone Remains…
Links in Backbone May Allow for Complete Degradation
Hybrid Pendant Biomass Approach
Petroleum
Renewable Resources
Bio-mass Monomers
Current Monomers
Acrylated Poly(lactic acid)
2-Hydroxyethyl Methacrylate
(HEMA)
Lactide (L)
Macromonomer
(MM)
Hybrid Adhesive Polymer
Generation of Adhesive Polymer Containing Acrylated Macromonomers
Macromonomer Production
Poly(BA-stat-L10C4)
Hybrid Adhesive Polymer
50% Macromonomer
Acrylated Poly(lactic acid)
(HEMA)
(L)
ε-Caprolactone
(C)
MM
Tg (°C)
L6
-26
L8
-20
L12
-8
L10C4
-38
(MM)
Generation of Adhesive Polymer Containing Acrylated Macromonomers
1580 1600 1620 1640 1660 1680 1700
Rel
ati
ve
Inte
nsi
ty
Wavenumber (cm )-1
T = 0 min
C=C
T = 120 min
(a)
0
20
40
60
80
100
0 20 40 60 80 100 120 140
Time (minute)
Co
nv
ersi
on
(%
)
(b)
Polymerization Success Stable Latex
Clear Film
95%
Polymerized
by 1 hour
1"
Shear Test ASTM Test Method
D 6463-99
Loop Tack Test ASTM Test Method
D 6195-03
180° Peel Test ASTM Test Method
D 903-98
500 g
1"
1" 1"
Commercial Adhesive Testing
Three tests used for comparing biomass PSA with commercial PSAs
Shear Test
1"
1,000 g
1"
Loop Tack Test
1"
180° Peel Test
1"
0
1
2
lbs/
in
Commercial Removable PSA Commercial Permanent PSA 50 % (wt/wt) L10C4 MM PSA
0
1
2
3
4
lbs/
in
10
102
103
104
Min
ute
s
Shear Loop Tack 180° Peel
Biomass PSA Comparison
Measuring Biodegradation (BOD)
Pressure Transducer and Needle
Alkali CO2 Trap
Test Sample and Sludge Inoculum
Rubber Stopper
Air Computer
Data Acquisition
Glass Test Jar
CO2
O2
Degradation of Components
-10
0
10
20
30
40
50
60
70
80
90
100
0 1 2 3 4 5
BO
D (
mg
/L)
Time (Days)
Buffer Only
Positive Control
Tackifier
Surfactant mix
L10C4
High Percentage of Biomass Tackifying Resins and Surfactants from
Renewable Resources
Ground
Tackifiers Biodegrade
Biomass Biodegrades
Backbone Remains…
Surfactants Biodegrade
Degradation of (Formulated) Biomass PSA
Friberg, T., Progress Paper Recycling, 1996, 6, 70 .
Generation of Contaminants from PSA Products
Research Objective and Approach
Development of new pressure sensitive adhesive (PSA) products that are engineered for enhanced PSA removal during the screening of recycled fiber
Benign Commercial Laminates PSA
PSA
PSA
Commercial Adhesives and Facestock
Database Generation & Analysis
Measurement of Screening Removal Efficiencies
for Laminates
Characterization of Bulk Mechanical and
Surface Properties
Synthesis and Formulation of Model and Commercial Systems
Identification of Key Characteristics for Benign Materials
Testing Removal Efficiencies of PSAs
Valley Flat Screen 15-cut screen
(0.38 mm slots)
PSA 0.5% PSA
Repulping Consistency = 10% 60 Hz (≈ 690 rpm)
Time = 30 min.
TAPPI Method T-205 om-88
Accepts Rejects
Cellulose Dissolution & Resin Oxidation
0.00g 1.23g
Removal Efficiency Quantified
gravimetrically
Removal Efficiency NOT Related to Dry Performance Properties
0
5
10
15
20
25
Pe
el S
tre
ngt
h (
N/2
5m
m)
0
10
20
30
40
50
60
70
80
90
100
Re
mo
val E
ffic
ien
cy (
%)
0
5
10
15
20
25
Pe
el S
tre
ngt
h (
N/2
5m
m)
0
10
20
30
40
50
60
70
80
90
100
Re
mo
val E
ffic
ien
cy (
%)
0
2
4
6
8
10
12
14
16
18
20
Loo
p T
ack
(N/2
5m
m)
0
10
20
30
40
50
60
70
80
90
100
Re
mo
val E
ffic
ien
cy (
%)
0
2
4
6
8
10
12
14
16
18
20
Loo
p T
ack
(N/2
5m
m)
0
10
20
30
40
50
60
70
80
90
100
Re
mo
val E
ffic
ien
cy (
%)
0
5
10
15
20
25
30
35
40
She
ar (
hr.
)
0
10
20
30
40
50
60
70
80
90
100
Re
mo
val E
ffic
ien
cy (
%)
Commercial Water -based PSA0
5
10
15
20
25
30
35
40
She
ar (
hr.
)
0
10
20
30
40
50
60
70
80
90
100
Re
mo
val E
ffic
ien
cy (
%)
Commercial Water -based PSA
0
5
10
15
20
25
30
35
40
Surf
ace
En
erg
y (
mJ/
m2)
0
10
20
30
40
50
60
70
80
90
100
Re
mo
val E
ffic
ien
cy (
%)
Commercial Water -based PSA0
5
10
15
20
25
30
35
40
Surf
ace
En
erg
y (
mJ/
m2)
0
10
20
30
40
50
60
70
80
90
100
Re
mo
val E
ffic
ien
cy (
%)
Commercial Water -based PSA
0 20 40 60 80 100 120 140
∆L (mm)
0.4
0.3
0.2
0.1
0.0
F (
N)
1”
Temperature
Controlled
Water Bath
PS
A (
1 m
il)
PET
strips
Fmax
Measuring the Strength of Water-Saturated Films
0 5 10 15 20
Soaking Time (min.)
0
0.2
0.4
0.6
0.8
1
1.2 M
axim
um
Ten
sile
Fo
rce
(N)
n-Butyl Acrylate – BA Methyl methacrylate – MMA Methacrylic Acid - MAA 2-Ethylhexyl Acrylate – EHA Vinyl Acetate – VA Acrylic Acid – AA
Poly(BA0.81-co-MMA0.16-co-MAA0.03)
Strengths of Water-based Acrylic PSAs in an Aqueous Environment
Poly(BA0.71-co-EHA0.10-co-MMA0.16-co-AA0.03)
Poly(BA0.71-co-EHA0.10-co-VA0.16-co-AA0.03)
Wet Strength vs. Removal Efficiency
0
10
20
30
40
50
60
70
80
90
100
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
Re
mo
val E
ffic
ien
cy (
%)
Wet
Str
en
gth
(N
)
M1 M4 M2 M6 M7 M5 M3 M9 M8
M1 - Poly(BA0.71-co-EHA0.10 -co-VA0.16-co-AA0.03) M4 - Poly(BA0.71-co-EHA0.10 -co-MMA0.03-co-VA0.16) M2 - Poly(BA0.71-co-EHA0.10 -co-VA0.16-co-MAA0.03) M6 - Poly(BA0.71-co-EHA0.10 -co-STY0.16-co-AA0.03) M7 - Poly(BA0.71-co-EHA0.10 -co-MMA0.16-co-AA0.03) M5 - Poly(BA0.71-co-EHA0.10 -co-STY0.16-co-MAA0.03) M3 - Poly(BA0.71-co-EHA0.10 -co-MMA0.16-co-MAA0.03) M9 - Poly(BA0.81-co-MMA0.08 -co-STY0.08-co-MAA0.03) M8 - Poly(BA0.81-co-MMA0.16 - co-MAA0.03)
Model PSA Latexes
Polymerization
Monomers, emulsifiers, other additives, and synthesis
approach
Formulation
Wetting agents, rheology modifiers, defoamers
and tackifiers
Coating
Coating technique and conditions, e.g., direct versus
transfer coating
The extent of film fragmentation during recycling operations is dependent on nearly all aspects of the label adhesive, paper and label production process
Breaking Down the Recycling Compatible PSA Problem
Laminate Design
Paper facestock properties and use of barrier coatings
and filler
Repulping
Wet Strength of Biomass PSA
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
We
t St
ren
gth
(N
)
M1 M4 M2 M6 M7 M5 M3 M9 M8
M1 - Poly(BA0.71-co-EHA0.10 -co-VA0.16-co-AA0.03) M4 - Poly(BA0.71-co-EHA0.10 -co-MMA0.03-co-VA0.16) M2 - Poly(BA0.71-co-EHA0.10 -co-VA0.16-co-MAA0.03) M6 - Poly(BA0.71-co-EHA0.10 -co-STY0.16-co-AA0.03) M7 - Poly(BA0.71-co-EHA0.10 -co-MMA0.16-co-AA0.03) M5 - Poly(BA0.71-co-EHA0.10 -co-STY0.16-co-MAA0.03) M3 - Poly(BA0.71-co-EHA0.10 -co-MMA0.16-co-MAA0.03) M9 - Poly(BA0.81-co-MMA0.08 -co-STY0.08-co-MAA0.03) M8 - Poly(BA0.81-co-MMA0.16 - co-MAA0.03)
B1
Biomass PSA Poly(BA/VA/MM0.5--co-MM0.5)
Challenges to Generating New PSA
Polymer Particle
Monomer Droplet
Conventional
Monomer Biomass
Macromonomer
“Macro” Emulsion Polymerization
Monomer Droplet
Sonicator
Challenges to Generating New PSA Mini-Emulsion Polymerization
Monomer Droplets ~200 nm
Plan Forward Alternative Polymerization
Method (solvent)
Impingement mixing
(mini-emulsion)
Cyclodextrin Multifunctional Additives
Commercialization
90 mass% adhesive polymer 2 - 10 mass% surfactant < 1 mass% everything else
Film composition {
Film formation
latex H H
O
H H
O
H H
O
H H
O
H H
O H H
O
H H
O
release liner
Dry film Emulsion
Fate of surfactant
Compatible Surfactant Phase-separated
Surfactant
Surfactant aggregations
Transport and Fate of Emulsifier
Poly(BA-co-VA-co-MAA)
Sample Preparation and Analysis
4 wt.% SDS in PSA
0
5
10
15
20
25
30
0 5 10
Surf
acta
nt
Co
nce
ntr
atio
n (
%)
Depth (um) #1 PSA #2 PSA #3 PSA
2.75
2.25
1.75
1.25
0.75
0.25
Ta
ck
Fo
rce
(N
/cm
2)
SDS
SDS
SDS
Pure
Latex
Pure
Latex
Pure
Latex
Benefits of Polymerizable Surfactants
Conventional Surfactant
CNPE
Polymerizable Surfactant
PNPE
W/ 4 wt% CNPE W/ No Surfactant (Dialyzed) W/ 4 wt% PNPE
0
1
2
lbs/
in
0
1
2
3
4
lbs/
in
Loop Tack 180° Peel
0
25
50
100
Min
ute
s
Shear
75
Poly(BA-co-VA-co-MAA)
Summary and Future Strategy • New high-biomass content water-based PSAs were synthesized via
substitution of acrylated macromonomers for traditional soft monomers in commercial formulations.
• Reactions via miniemulsion polymerization are rapid and produce stable latexes, and cast films are crystal clear and demonstrate tack, peel and shear performance that meets or exceeds that of most commercial products.
• Furthermore, the films have a high wet strength consistent with high removal efficiencies that are not degraded by factors such as formulation, production and product design.
• Research efforts will include the optimization of the new adhesive and approaches for engineering performance and increasing sustainability.
• However, the main focus, at least initially will be the development of a synthesis approach for generating the PSA at the commercial scale.
Acknowledgements
USDA and DoE
Franklin International
Jiguang Zhang – UMN/Dow
Monique Lander – UMN/EcoLabs
Gang Pu – UMN
Matt Dubay – UMN
Carl Houtman - FPL
Renewable and Biodegradable Monomers for Adhesive Materials
Steve Severtson
University of Minnesota