How to control Stickies and pitchy on paper machine

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. In pulp and paper production fixation agents are used to fixate pitchy or stickies to the paper fibers to transport the problems out of the production process and have a cleaner production plant.

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