The pulping and p p g deposition of macro stickies

The p
pulping
p g and
deposition of macro
stickies
Xi Huo,
Xin
H
Richard
Ri h d A.
A Venditti,
V ditti H
Hou-min
i Chang
Ch
North Carolina State University
D t off Wood
Dept.
W d and
dP
Paper S
Science
i
What are stickies?
Stickies in paper recycling are believed to
be a mixture of
----Hot melts adhesives
----Pressure-sensitive
P
i i adhesives
dh i
(PSA’
(PSA’s))
----Wax
----Coating
Wood derived extractives
----Wood
Stickies
A sticky particle
• is typically hydrophobic
• is
i tacky
t k andd depositable
d
it bl
• often adsorbs particulates/dissolved species
• Examples of adsorbed species might include talc,
Calcium Carbonate, Inks, Toners, polymers …
*The actual surface behavior of stickies
depends on the adsorbed species.
PSA Surface
PSA Surface with CaCO3
Stickies-Related Problems
• Product quality
– Dirty
Di t spots
t in
i paper *
• Operational
p
problem
p
– Deposition on machine *
– Breaking web
* Affected by adsorbed species.
species
Control and Removal Methods
for Stickies
– Mechanical removal *
– Chemical control *
– Use of environmentally benign adhesive
(recyclable adhesive)
– Control of waste paper quality
– Physical
y
adsorption
p
to ppaper
p fibers *
– Others
* Aff
Affected
t d by
b adsorbed
d b d species.
i
The effect of pulping conditions on the
size of stickies after pulping
• Objective: how do components present in
the pulper affect the size and shape of
stickies after pulping
• Agglomeration?
A l
ti ?
List of Furnishes
• Copy Paper, alkaline
– CaCO3 (11%)
• SW Market Pulp
– pH = 5.0, 5.7, 9.5
• Bristol Paper
– 2% Rosin, 4% Alum,
10% C
Cationic
i i Starch
S h
• Market Pulp +
–
–
–
–
–
–
CaCO3 (11%)
Talc (11%)
Clay (11%)
Sized with AKD
Cat Starch (1.5 & 10%)
Alum (4%)
All furnishes contained 0.5% acrylate based PSA.
Pulping Experiment Procedure :
400 g OD Pulp
2 g adhesive
PULP
12%K, 40 C
30 min
HANDSHEETS
Dyeing
Image Analysis
Dyeing Stickies for Contrast Enhancement
Wire or HS
Morplas Blue - Heptane Dye Solution
Image Analysis:
Apogee Image Analysis System
HP ScanJet 4C
600 dots per inch
Threshold: 80% Avg. GSV
Both sides of 4 PM Wires
Effect of Papermaking Components on Stickies
Average
g Size After Pulping
p g (Maelstrom
(
Pulper)
p )
Talc(11%)+Mkt
C CO3(11%) Mk
CaCO3(11%)+Mkt
Starch(1.5%)+Mkt
Rosin/alum/starch
In bristol Paper
pH5.0+Mkt
pH9.5+Mkt
Market Pulp
(pH=5.7)
Copy
0
1
2
Average Size (mm2)
3
Effect of Papermaking Components on Stickies
Average Size after Pulping ( 450H Pulper)
AKD Sized Paper
Rosin/alum /Starch
Bristol paper
Starch (10%)+Mkt
Rosin (2%)+
(2%) Mkt)
Alum (4%)+Mkt
Market Pulp
0
0.5
1
1.5
2
Average Size (mm2)
2.5
3
MARKET PULP
COPY PAPER
Effect of Paper Making Components
on the Shape Stickies
Market Pulp (pH=5, 5.7,9.5)
Clay
CaCO
3
Copy Paper
Rosin/alum/starch
Mkt Pulp w/ Cat. Starch
Mkt Pulp w/ Talc
A closer look at polymer adsorption
on stickies agglomeration
–T
To understand
d t d the
th process off th
the stabilization
t bili ti off
stickies (prevention of agglomeration or
deposition) by starch.
starch
• Objective
– To understand the process of the stabilization of
stickies (prevention of agglomeration or
deposition)
p
) byy starch.
Experimental Procedure
Deionized water
0.2 ggram of PSA particles
p
((collected
from reject of lab screen)
Poly-DADMAC
y
or starch
45oC for 8 hours
PSA Particle Aggregates
(no chemicals)
PSA Particles
Gentle Stirring
(0.05% Cat Starch solution)
Concentration and Charge of
Poly-DADMAC
Poly-DADMAC
Poly
DADMAC
Concentration
Charge
Result
(g/liter)
(µeq/liter)
0
0
A l
Agglomerate
t
4.83E-5
0.3
Agglomerate
6.44E-5
0.4
No agg.
9.66E-5
0.6
No agg.
1.45E-4
0.9
No agg.
2.42E-4
2.42E
4
1.5
No agg.
4.84E-4
3.0
No agg.
Ave
erage Size
e of PSA P
Particles
(m
mmsq)
Effect of Starch Stabilization on
PSA Particles
4
3.5
Starch 700 (cationic starch w ith
DS=0
DS
0.043)
043)
3
Starch 500 (cationic starch w ith
DS=0.021)
2.5
Starch OP (neutral starch)
2
Poly-DADMAC (DS=1)
1.5
1
PVSK (DS=1)
05
0.5
0
-5
0
5
10
Dosage of Polymer (% of OD fibers)
Stickies deposition on papermachine
fabric
• Objective: determine how components
present in the pulper affect the deposition of
stickies on papermachine fabric
Deposition Procedure:
400 g OD Pulp
2 g adhesive
PULP
12%K 40 C
12%K,
30 min
DEPOSITION
0 5%K 50 C
0.5%K,
30 min
PM Wires
Dyeing
Image Analysis
Stickies Deposition Tester
Papermachie
wire
Stickies Deposition Tester
Motor
Gears
Paddle
Water Bath
Stickies Deposition (Weight Method) for
Various Papermaking
g Components (Maelstrom
(
Pulper))
Clay(11%)+Mkt
Talc(11%)+Mkt
CaCO3(11%)+Mkt
Starch(1 5%)+Mkt
Starch(1.5%)+Mkt
Rosin/Alum/Starch
in Bristol Paper
pH5 0+Mkt
pH5.0+Mkt
pH9.5+Mkt
Market Pulp(pH=5
Pulp(pH=5.7)
7)
Copy
0
0.1
Mass of Deposits (g)
0.2
0.3
Stickies Deposition (Weight Change) for Various
Papermaking Components (450H Pulper)
AKD Sized Paper
p
Rosin(2%)+ Mkt
Alum (4%)+Mkt
Second
First
Starch(10%)+Mkt
0
0.05
0.1
0.15
Mass of Deposits (g)
0.2
Major Findings:
• The stickies will self-agglomerate in pulper
without the interference of chemical additives
• Components
p
in copy
py ppaper
p like cat starch
can disperse the stickies and make them more
string-like
g
•Cationic starch,, alum and talc can prevent
p
deposition of the stickies very effectively