Stickies on (papermaking)
Stickies are
tacky substances contained in the paper pulp and process water systems
of paper machines. Stickies have a large
tendency to make deposits on the processing equipment in certain stages of the papermaking process. Contaminations of paper that that are classified as
tacky are also called stickes. The main sources for stickies are recycled paper waxes, and soft adhesives .....(From Wikipedia, the free
encyclopedia)
Stickies
are an indefinite mixture of organic compounds, with the main part being different esters. The components might come from:
§ Printing inks
§ Coating binders (synthetic latex)
§ Waxes
§ Hot melt adhesive and unsupported pressure sensitive
adhesives
§ Plastics
§ Wet
strength resins
§ Pitch
§ Papermaking additives
(Clasification of Stickies)
Stickies
that passes through a slotted plate screen of 0.10 - 0.15 mm are called micro stickies,
Which can be finely dispersed (100 µm - 100 nm),
colloidal (100 - 10 nm) or molecular
dissolved ( < 10 nm). Macro
stickies are those who retain as a screening residue. The reason
for this
classification is that macro stickes are easy to remove from the deinked pulp in the
deinking process with filtration. Micro stickies follows the pulp to the paper
machine and might
agglomerate and cause problematic deposits. Stickies
have often thermoplastic
properties.Chemical-physical
alterations like pH, temperature and charge changes might
cause
colloidal destabilization and agglomeration of micro stickies.
¡MACRO STICKY ( > 150 micron )
Mechanical
Treatment
Screening
Cleaning
Dispersis
Clarification
¡MICRO STICKY ( < 150 micron )
Chemical Treatment
Deposite
Fixation Agent
Pulmac Tester
(Stickies Control)
Mechanical Treatment
Several
methods are used to control the are used:
§ Alteration of the physical properties, like
using recycling friendly paper coatings,
§ Avoidance of troublesome components that causes
stickies,
§ Removal by more effective deinking process, like improved screening, cleaning,
washing and flotation,
§ Passivation with process additives like fixation agents, Prevention by washing wires
or protecting equipment parts with chemicals
Stickies on Doctor Blade
Chemical Treatment
Fixation Agent
A fixation agent is a chemical that is capable to fixate one substance to another
substance that the first substance have little affinity to.
As fixation agents used in pulp and paper production are minerals
like talc and bentonite or different cationic polymers like polyDADMAC. The
polymer based fixation agents are often called detackifiers as they reduce the tackiness of the pitch and stickies.
Important Step of control stickies
Mapping Stickies
The most importantly on control stickies are first step of control whole area so that how we can mapping all area where stickies come from and how many they are on each area on paper machine from stock preparation unit until production on wire calendering, what caused stickies agglomeration, what chemical involved on each part of machines, if we can do all the mapping project, we can continuously choose which treatment are the best treatment and control we can playing to. so all average total amount stickies normally can be healing to minimize.
Example of stickies mapping on Recycle Mapping
From brick graph above Total number of sticky decomposed lies in the stock preparation Pre flotation (DIP) and Mixing Chest(Paper Machine) more >>>> see brick graph above.
After 5-6 times of mapping we can take an action with Mechanical Treatment. Deinking process occurs or Chemical Treatment. (Note : Elections and chemical dosing and chemical injection point are very specific important)
Example of stickies mapping on Recycle Mapping
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