Development ofDevelopment of ScreenableScreenable WaxWax Coatings and WaterCoatings and Water--BasedBased

Pressure Sensitive AdhesivesPressure Sensitive AdhesivesProject DE-FC36-04GO14309

Principal Investigator: Steve Severtson - University of Minnesota

Research Partners: USDA FS Forest Products Laboratory

Franklin International The International Group

Boise Cascade Corporation

Generation of Contaminants fromGeneration of Contaminants from PSA Films and Wax CoatingsPSA Films and Wax Coatings

PSA films and wax coatings fragment during repulping

partial removal via conventional cleaning techniques

. .

.. . ..

.

.

.. .

WASTE

. .

. .. .

.

.

.

.

.

aggregation and deposition

retention in the sheet

REPULPING reduced energy efficiency, lost production

and diminished product quality

. .

MILL PRODUCTION Reduced Efficiency, Added Cleaning

and Waste Handling Costs

$527 MM LANDFILLING

Increased Process Waste

$14 MM

Annual Cost to U.S. Paper ProducersAnnual Cost to U.S. Paper Producers

$150 MM

RAW MATERIAL Downgrading of Recovered Paper

Sources: Friberg, T., Progress Paper Recycling, 1996, 6, 70 . 2004 AF&PA Recycling Task Group Report, AF&PA/FBA Symposium, October 10, 1996, Chicago.

In addition to the economic impact, it is estimated that an extra 800 MWh are consumed by industry due to PSA and wax contamination

and greater than 1 million additional tons of fiber is landfilled

Project ObjectiveProject ObjectiveDevelopment of product engineering approaches to provide for enhanced

PSA and wax coating removal during the screening of recycled fiber

development of wet-end recipes for paper that promotes PSA and wax removal

characterization of coating-substrate adhesion and

development of techniques for manipulating adhesion to

enhance removal

identification of properties that govern PSA and wax coating removal and development of benign formulations

The impact on paper recycling operations should be a design parameter in the development of all adhesive and coating systems formulated for paper applications

Project StructureA Complimentary Partnership

Research Strategy

Identification of Key Characteristics for Benign Materials

Synthesis and Formulation of Model and Commercial

Systems

Laboratory and Pilot Testing of Screening Removal Efficiencies

Database Generation

& Analysis

Output Commercially Feasible

Benign Products

Characterization of Bulk Mechanical and Surface

Properties

Input Access to Existing

Product Lines

Input Commercial Assessment

of New Product Approaches

EnviroSensitive LabelsADvanced labels are designed to meet environmental guidelines – specifically executive order EO13148-- Greening the Government Through Leadership and Environmental Management. This product utilizes arepulpable face stock and repulpable adhesive making it recyclable. The XonadTM process further reducesthe amount of adhesive required on each sheet. ADvanced Labels are guaranteed not to jam in any laser orInkjet printers or photocopy equipment.

Benefits:• Environmentally Friendly• Repulpable EnviroSensitiveTM Adhesive and Facestock• Multi-purpose• Contamination-free technology• Compatible with all label software• Premium quality construction• Lay-flat/stay flat construction• Guaranteed to work

To place your order contact Customer Service @ 1-800-777-2879

Business Media DivisionBuffalo, New York

EnviroSensitive Labels

Benefits:• Environmentally Friendly• Repulpable EnviroSensitiveTM Adhesive and Facestock• Multi-purpose• Contamination-free technology• Compatible with all label software• Premium quality construction• Lay-flat/stay flat construction•

Commercialization of Benign Hot-Melt PSAProject DE-FC07-00ID13881

Research on water-based PSAs and coating wax are an extension of this project.

ADvanced labels are designed to meet environmental guidelines – specifically executive order EO13148 -- Greening the Government Through Leadership and Environmental Management. This product utilizes a repulpable face stock and repulpable adhesive making it recyclable. The XonadTM process further reduces the amount of adhesive required on each sheet. ADvanced Labels are guaranteed not to jam in any laser or Inkjet printers or photocopy equipment.

Guaranteed to work

To place your order contact Customer Service @ 1-800-777-2879

Business Media Division Buffalo, New York

EnviroSensitive Labels ADvanced labels are designed to meet environmental guidelines – specifically executive order EO13148-- Greening the Government Through Leadership and Environmental Management. This product utilizes arepulpable face stock and repulpable adhesive making it recyclable. The XonadTM process further reducesthe amount of adhesive required on each sheet. ADvanced Labels are guaranteed not to jam in any laser orInkjet printers or photocopy equipment.

Benefits: • Environmentally Friendly • Repulpable EnviroSensitiveTM Adhesive and Facestock • Multi-purpose • Contamination-free technology • Compatible with all label software • Premium quality construction • Lay-flat/stay flat construction • Guaranteed to work

To place your order contact Customer Service @ 1-800-777-2879

Business Media DivisionBuffalo, New York

PS Laminate Engineering - matching the right PSA with the facestock properties required to eliminate the negative impact of the adhesive on paper recycling

HotHot--Melt PSAsMelt PSAs

Easily Shaped for Characterization

Melt Processing

G′, G″, Tan δ

20-50 wt. % Base Polymer

30-60 wt. % Tackifier 0-25 wt. % Plasticizer

WaterWater--Based PSAsBased PSAsEmulsifier(s)

Initiator(s)

Buffer(s)

Tackifying Dispersion(s)

Monomers

Adhesive Emulsion

Crosslinking Agents

Biocide(s)

Formulated PSA Processing requires

coating of low energy substrate and drying

Wetting Agent(s)

Rheology Modifiers

Defoamer(s)

Characterization samples restricted to thin films with

properties dependent on formulation

Polymerization

Formulation

G′, G″, Tan δ ?

0

Rem

oval

Eff

icie

ncy

@ 5

0°C

(%)

Removal Efficiency for Base EmulsionsRemoval Efficiency for Base Emulsions100

Benign No evidence for dependence of screening removal efficiency on PSA properties such as

80

• Tack60

• Peel 40 • Shear

• Tensile Properties (E, TS,%EL,…)20

• Glass Transition Temperature

• Surface Energy Water-based PSA

Unlike that found for hot-melt PSA, dry mechanical properties and phase behavior for water-based PSA do not correlate with repulping and screening performance

PSA Properties and Wet ProcessingPSA Properties and Wet ProcessingProbe Tack Tensile Strength

Prob

e T

ack

(N)

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9 1 mil Film

@ 25°C Soaked in water for 1 min

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

Ten

sile

Loa

d (N

)

1 mil Film @ 25°C

Soaked in water for 1 min

Threshold of RE

Water-based PSA Water-based PSA

Monitoring Influence of MoistureMonitoring Influence of Moisture

Desorption (Chemical Analysis,

Surface Tension)

Adsorption (QCM,

Microgravimetry)

Water Immersed

Mechanical Testing (AFM, Nanoindentation)

in situ PSA Film Characterization

Film Formation

Latex Properties

-

-

---

--

-

-

-

-

---

--

-

-

-

-

---

--

-

-

-

-

---

--

-

-

-

-

---

--

-

-

• Monomer Composition • Surfactant System • Particle Size Distribution • Crosslinking Degree • Other Additives

-

-

---

--

-

-

Film Analysis

Cryo-SEM

Current Status of ProjectCurrent Status of Project• Influence of processing additives on PSA film properties

and on screening removal efficiencies was examined.

• Approach developed for preparing laboratory PSA films for transfer coating containing only the adhesive latex.

• Properties and removal efficiencies of >25 commercial water-based PSAs were measured. This required the development of new “in-situ” tests involving the building of in-house equipment not commercially available.

• Potential dominant properties governing removal efficiencies were identified and are currently being pursued through model formulations.

• Several model water-based PSAs are currently under study.

-20

-10

0

Hea

t Flo

w (m

W)

Paraffin Wax CoatingsParaffin Wax Coatings

0

2

4

6

8

10

12

14 Wax Market

Paraffin Wax +

)

PolymerImpreg. 15%

Saturating 60%

Curtain Coating 25%

Ten

sile

Str

ess (

MPa

) %

Nor

mal

Alk

ane

Polymer (< 5%

Paraffin Wax + (20-25%)

Paraffin Wax 20 22 24 26 28 30 32 34

Carbon Number1.0

Endo

T = 20°C 0.8

T = 25°C 0.6

0.4

0.2 T = 30°C

-40 0.025 30 35 40 45 50 55 60 65 0 20 40 60 80 100

Temperature (oC) Tensile Strain (%)

-30

Wax Deposition and RemovalWax Deposition and Removal

20 25 30 35 40 45 50 55 60 0

20

40

60

80

100

Rem

oval

Eff

icie

ncy

(%)

Temperature (°C)

0

20

40

60

80

100

Dep

ositi

on (%

)

Mesophase Region

20 25 30 35 40 45 50 55 60

Temperature (°C)

Mesophase Region

Wax Composite and NanocompositeWax Composite and Nanocomposite

0 10 20 30 40 50 0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4 Pure paraffin wax Wax- 17 wt% clay

Ten

sile

stre

ss (M

Pa)

Tensile strain (%)

0 10 20 30 40 50 0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4 Pure paraffin wax Wax- 0.5 wt% OMMT Wax- 5 wt% OMMT

Ten

sile

stre

ss (M

Pa)

Tensile strain (%)

Composite

Nanocomposite

Ultrasonic Processing

Paraffin Wax 0.5 – 5%

OrganoClay

surfactant intercalation

Tensile

Properties

Tensile

Properties

Paraffin Wax

Melt Processing

Dispersant

17% Clay Filler

Wang, J., Severtson, S. J., Stein, A., Advanced Materials, In Press.

Performance Testing ofPerformance Testing of NanocompositeNanocomposite and Scale Upand Scale Up

Mechanical Compounding

Solid Feed

exfoliated and evenly distributed

platelets

Commercially Feasible Compounding

. .

.. . ..

.

.

. . . . .

Screening Removal Efficiency Barrier and Strength Properties

Both Laboratory and Pilot-Scale Testing

PP

Permeation of Gasses and Liquids and Influence of Exposure on Strength

Current Status of ProjectCurrent Status of Project• Both laboratory and pilot scale tests developed for gauging

screening removal efficiencies.

• Structure (molecular, nano- and micro-) and bulk mechanical and surface properties of IGI commercial coating waxes were characterized.

• Screening removal efficiencies and deposition tendencies were measured as a function of temperature.

• Clay-wax composite properties and performance were examined. This included pilot-scale testing of the IGI product. Results led to the development of an organoclay-wax nanocomposite produced via sonication.

• Mechanical properties of the composite and melt were characterized and its compounding using a laboratory compounding equipment below the melt point was demonstrated.

Current Milestone ChartCurrent Milestone ChartID Description Planned Actual No. Completion Completion

Date Date

1 Characterization and removal testing of Franklin 10/05 10/05 label grade water-based PSAs

2 Characterization and removal testing of standard 10/05 10/05 wax coatings

3 Characterization and removal testing of new model 10/06 water-based PSAs Criterion for proceeding – Properties identified as

those governing fragmentation are confirmed

4 Study on the role of facestock properties in 10/06 determining removal of PSAs

5 Characterization and removal testing of new model 04/07 wax coatings Criterion for proceeding – Properties identified as those governing removal are confirmed

6 Development of new benign commercial PS labels 11/07 Criterion for proceeding – Laboratory results confirmed for PS labels at pilot scale

7 Study on the role of board properties in 08/07 determining removal of wax coatings

8 Development of new benign commercial treated 11/07 corrugated containers

AcknowledgementsAcknowledgements• Jihui Guo (U of MN) • Jinfeng Wang (U of MN) • Mark Calhoun (U of MN) • Larry Gwin (Franklin) • Carl Houtman (FPL) • Karen Scallon (FPL) • Jamie Kalyta (IGI) • Roman Kinasz (IGI) • Fei Wang (IGI) • Jennifer Lien (Boise) • Keith Hays (Penford Products)

Questions andQuestions and DiscussionDiscussion

Testing PSA Removal EfficiencyTesting PSA Removal Efficiency

Adirondack Formax 1800H & 450H Pulpers

•consistency = 10% • 60 Hz (≈ 690 rpm) • typical time = 20 min.

. . .

.

. .

.

. . .

. . .. .

.

.

.

. TAPPI Method

T-205 om-88

AcceptsRejects . .

.

. .Valley Flat Screen

15-cut screen (0.38 mm slots)

Paper Shredder

1/4″ strips

.

. . . .

labels are attached to sheets in a sample

of copy paper PSA content = 0.5%

PSA film is pressed onto handsheets

.....

removal efficiency is quantified

gravimetrically

Cellulose Dissolution & Resin Oxidation

(when required)

Removal Efficiency

IA Area Fraction∝

.

..

.

..Valley Flat Screen15-cut screen

(0.38 mm slots)

. ..

Testing the Removal Efficiency of WaxTesting the Removal Efficiency of Wax

Adirondack Formax Temperature Control

Pulpers • consistency = 3% • 60 Hz (≈ 690 rpm) • typical time = 20 min.

. . .

.

. .

.

. . .

Accepts

. . . ..

Rejects

. .

Valley Flat Screen 15-cut screen

(0.38 mm slots)

Wax

ASTM standard D590-93

Weight of wax screening rejectsWax removal efficiency =

Weight of initial wax in wax-coated boards × 100%

3 % wax

FBA Voluntary Standard

Modeling the Fragmentation BehaviorModeling the Fragmentation Behavior of Thermoplastic PSA Formulationsof Thermoplastic PSA Formulations

PSA T50(°C) α(°C) SAFT(°C) 0.10∆Τ(°C) 100 PSA 1 58 3.6 57 4.7PSA 1 58 3.6 57 4.7PSA 2 46 3.2 47 3.7PSA 2 46 3.2 47 3.7

80

Rem

oval

Eff

icie

ncy

(%)

PSA 3 61 3.8 57 3.9PSA 3 61 3.8 57 3.9PSA 4 48 3.9 51 4.4PSA 4 48 3.9 51 4.4PSA 5 55 3.0 56 4.0PSA 5 55 3.0 56 4.0 60PSA 6 45 4.1 49 4.6PSA 6 45 4.1 49 4.6PSA 7 46 2.3 49 3.8PSA 7 46 2.3 49 3.8PSA 8 54 6.1 54 5.9PSA 8 54 6.1 54 5.9 40PSA 9 52 1.9 51 4.2PSA 9 52 1.9 51 4.2PSA 10 56 3.2 53 4.7PSA 10 56 3.2 53 4.7PSA 1b 78 5.7 74 7.1PSA 1b 78 5.7 74 7.1 20PSA 2b 63 8.7 58 7.0PSA 2b 63 8.7 58 7.0PSA 3b 78 11.7 72 7.3PSA 3b 78 11.7 72 7.3PSA 10b 61 7.5 62 6.9PSA 10b 61 7.5 62 6.9 0

0 20 40 60 80 100 Temperature (oC)

exp ⎜⎛ T50 − TR ⎞⎟ EfficiencyRemoval = ⎝ α ⎠ × %100

1 + exp ⎜⎛ T50 − TR ⎞⎟ ⎝ α ⎠

* 14 Thermoplastic PSA formulations with rosin ester and C5 hydrocarbon tackifying resin systems* Predicted removal efficiency –vs- experimental removal efficiency ⇒ Slope = 0.99, Intercept = 0.07, R2 = 0.98 (140 points)

-20 -10 0 10 20

Rem

oval

Eff

icie

ncy

(%)

Temperature (°C)

60

80

100

0 20 40 60 80 100

60

80

100

0 20 40 60 80 100

T0.10T-SAFT R

∆

0

20

40

TemperatureTemperature--Dependent Repulping ResultsDependent Repulping Results

Predicting Thermoplastic PSA Recycling PerformancePredicting Thermoplastic PSA Recycling Performance

Temperature (oC)

0

20

40

60

80

100

0 20 40 60 80 100 120

Rem

oval

Eff

icie

ncy

(%)

Predicted Removal

Commercial PSA 1

Commercial PSA 2

0

2

4

6

8

10

12

14

SAFT

Tan

δ

SAFT = 48.9°C ∆T = 56.6 °C

2

4

6

8

10

12

14

SAFT

2

4

6

8

10

12

14

SAFT

∆Τ

Commercial PSA 1

0.5

1.0

1.5

2.0

2.5

3.0

3.5

0.5

1.0

1.5

2.0

2.5

3.0

3.5

0.5

1.0

1.5

2.0

2.5

3.0

3.5

SAFT

∆Τ

SAFT = 79.4°C ∆T = 63.5°C

Commercial PSA 2 T50 = 49oC α = 5.7oC

T50 = 79oC α = 6.4oC

α = 0.10∆T

0 40 -2040 -20- 000 20 4020 40 60 80- 40 20 20 40 60 8060 80 100 120100 120100 120

Temperature (°C)

PSA

-Fac

e St

ock

Adh

esio

n

Face Stock Tensile Loss

Energy,

Face Stock

Increasing Removal

Efficiency

increasing fiberous of face stock

Removal Efficiency

Energy,

Face Stock

Low Surface

Non-Fiberizing

rejects via screening complete fiberization

Minimized

No Influence on Removal Efficiencies from Face Stock

High Surface

Readily Fiberized