Description
SKHZYE-DGM*3
Stickie
reducing enzyme for “stickies” removal
INTRODUCTION
The
problems caused by stickies are many and varied and can occur at
practically every stage in the papermaking and paper conversion
chain including printing. Finding a suitable way to treat them can
be difficult..
The
problem is complicated by the fact that there are two types of
stickies:
(1)
Primary stickies, insoluble components that are tacky under normal
conditions and are present in the incoming recycled paper and
coated broke, e.g., hot melts or pressure sensitive adhesives,
inks, waxes, plastics, synthetic adhesives, resin size,
wet-strength resins, and binders; and
(2)
Secondary stickies, composed of the soluble components of adhesives
and chemicals used in papermaking and converting. Secondary
stickies are formed as a consequence of sudden changes in wet end
chemistry, temperature or pH, when they react to produce insoluble
or gel-like tacky particles. They can be more difficult to handle
than primary stickies.
The
problems caused by these tacky impurities are all too familiar.
Deposits occur on stationary parts of a processing system such as
pipes and chest walls and in the approach flow system. This
includes the headbox itself due to the adhesive character of these
materials. Deposits primarily influence moveable parts such as
wires, felts, or rolls. Stickies will end up in the final paper
produced and cause quality problems aesthetically and in its
subsequent use.
Deposits within the paper machine can
cause:
Web breaks due to weak spots and
localized sticking to moving rolls
Picking of fibers
Lengthy nonproductive cleaning
times due to build-up on wires, felts, rolls & doctor
blades
Deposits in/on the paper can
cause:
Increased downgrades due to
contribution to dirt count
During converting processes at high
temperature/pressure, migration of stickies from inside of paper
reaches outside of paper. This is particularly costly when goods
are returned after printing, varnishing or laminating.
Converting problems due to adhesion
between sheets. Problems during unwinding of a reel causing breaks,
surface blemishes, or misfeeds in sheet-fed
process.
SKHZYE-DGM*3is an enzyme preparation intended for use in
reducing stickies in recycled pulps. Properly applied microbial
enzyme–based products can enhance the release of stickie particles
from the fiber surface and facilitate its removal by flotation.
TECHNOLOGY
The
mechanisms by which “SKHZYE-DGM*3” preparations facilitate stickie removal
are:
Unique blend of cellulase and other
enzymes aid in releasing stickie particles from fiber surfaces by
the same mechanism used to describe enzymatic toner ink
removal.
Gentle neutral pH pulping keep
stickie particles large so that many can be screened out of the
slurry. Alkaline pulping increases the tackiness and solubility of
the adhesives during conventional alkaline treatment.
Fibrils attached to stickie
particles are severed, thus facilitating removal of the additional
stickies by flotation.
Secondary benefits associated with
“SKHZYE-DGM*3” usage include enhancement of fibre yield and
improvement in physical strength. This would lead to reduced
consumptions in wet-end chemicals such as retention aids, wet
strength agents, starches etc., thus reducing the build-up of
secondary stickie causing components in the process
water.
PRODUCT DESCRIPTION
SKHZYE-DGM*3 is a complex enzyme preparation intended
primarily for stickies reduction in deinking pulp mills and
papermills using recycled fibers. SKHZYE-DGM*3is a powdered
form of a blend of cellulase and other enzymes operating between a
broad range of pH (4.**9.0) and temperature (****0°C) and is used
in the range of ******0 g/ton of dry pulp.
The
SKHZYE-DGM*3 product is in liquid form, with a tan to orange
color, a slight fermentation odor, miscible with water and has a pH
of 5.5±1.0 at *0oC.
BENEFITS OF SKHZYE-DGM*3
Primary Benefits (Stickies
Removal)
- Elimination of the need for soda pulping.
Neutral pulping can be used.
- Improvement in quality.
- Improved stickies removal
efficiency.
- Lower
cost (higher contamination) raw materials can be
utilized.
- Reduction in downtime due to cleaning and
sheetbreaks.
- Improves quality of process water. Lower COD,
less toxic and contain fewer micro-stickies
- Greater customer satisfaction
Secondary
Benefits
- Elimination of the need for soda
pulping.
- Reduction in REFINING ENERGY. Reduction in
Refining time or Amperage leading to a reduction in electrical
costs.
- Improvement in FIBRE YIELD. Increase in fines
retention from increased fibrillation (micro-fibrillation). Helps
to reduce build-up of fines in forming and press fabrics,
increasing fabric life.
- Improvement in WASTEWATER QUALITY. Reduction of
fines and the cleaning of white water loops.
- Improvement of PAPER STRENGTH properties.
Enhances paper strength by increasing inter-fiber bonding through
fibrillation (micro-fibrillation).
- Improvement in MACHINE RUNNABILITY. Cleaner
whitewater system helps to reduce slime build up that causes
sheetbreaks.
- Reduction in STEAM LOADING or INCREASE IN
PAPERMACHINE SPEED. Improvement in drainability leading to either
the reduction of steam demand for paper drying or conversely
increases in the paper machine speed.
- Improvement in PAPER QUALITY. Improvement in
paper formation due increased fines retention and more efficiently
refined pulp. Reduction in vessel picking during printing of paper
produced with hardwood virgin pulp.
- Savings in RAW MATERIAL costs. Allows the use
of lower quality and cheaper furnishes.
- Savings in CHEMICAL costs. Reduction in
consumption of retention aids and strength enhancing
chemicals.
APPLICATION
SKHZYE-DGM*3 is a complex enzyme preparation intended
primarily for stickies reduction in deinking pulp mills and
papermills using recycled fibers. Almost every mill has unique
conditions of fiber processing. The optimal dosage can also depend
on the temperature, pH and consistency of the pulp. Application
protocols for SRE can be tailored to best suit the specific
process. However, the following general application optimal
conditions can be used.
Dosage：******0 g/ T pulp (normally added at
the
hydropulper to ensure uniform
mixing)
Pulp properties： pH 7.0
Temperature: between *0
and *0℃
Termination: can
be inactivated by raising the pH above *1 or
the temperature above *1°C
(**0°F)
Experimental
White Office Waste was charged with acrylate
PSA (pressure sensitive adhesive) and pulped in hydropulper at
*5oC. The pH was adjusted to compare alkaline and neutral pulping
effects. Pulp was then subjected to the same flotation and
screening (0.*5mm) process. Residual stickies (ppm) on dyed
handsheets were measured using a flatbed scanner and image analysis
software.
Results
|
Pulping treatment
|
Stickies (ppm)
|
|
0.*2 to 4.0 mm2
|
< 0.*2 mm2
|
|
Alkaline pH (*0)
|
**0
|
**6
|
|
Neutral pH (7)
|
**4
|
*8
|
|
Cellulase (competitor) treated , pH
7
|
**0
|
*3
|
|
SUKASRE**3 treated (pH 7)
|
**2
|
*7
|
*Starting pulp impregnated with PSA contained
**0ppm adhesive particles
STORAGE
Store in cool, dry place and away
from direct sunlight. The product maintains its activity for
considerably longer time when stored at lower temperatures (below
*5℃). When stored in sealed containers, under cool dry
conditions, SKHZYE-DGM*3has a loss of activity of normally
less than *0% over one year.
The product should not be
frozen.
HANDLING PRECAUTIONS
SKHZYE-DGM*3 is non-toxic and biodegradable. However,
unnecessary contact wi
