Eliminating A Common OCC Stickies Problem Matthew A. Blazey Ciba Specialty Chemicals Water & Paper Treatment
Sustainability Day at Green Earth Elementary Please welcome the CEO of Reuseit Paper
Sally s Question... Why can t you use 100% recycled fiber?
D OH! If she only knew my hot melt stickies problems...
What Sally Doesn t See Hot Melt Stickies
What are Hot Melt Stickies? Hot melt adhesives Typical applications include Magazine and book binders Bag and carton sealing Chemically identified as ethylene vinyl acetate (EVA) copolymers and hydrocarbon wax
Where Do They Come From? Common sources include old corrugated containers (OCC) and old magazines (OMG)
What is Their Impact?
Solutions for Hot Melt Stickies? Use of Cleaner Fiber Sources Increased costs Screening / Cleaning Many stickies still smaller than microscreen dimensions Hot melt stickies semisolid at stock temps so extrusion through holes/slots possible Density of hot melts comparable to water so centrifugal cleaning is inefficient Fixation / Passivation Attach microstickies to fiber/fines and remove via finished sheet Render remaining stickies nontacky
Fixation / Passivation Strategy Adsorption of dispersed microstickies onto a modified smectite clay (Ciba Cedesorb ) Smectite clay passivates macrostickies Use cationic fixatives (Ciba Alcofix )to retain smectite/stickies complexes onto fiber/fines
Cedesorb Characteristics 1 micron Top View 300 nm + + + + + + + 0.9nm thick
Adsorbing Colloidal Stickies Hot Melt Stickies + Smectite Clay
Retention of Adsorbed Stickies Onto Fines Smectite / Stickies Complex Fiber Fines + Polymer Fixative
Passivation of Macrostickies Macrostickie + Smectite Clay Passivated Macrostickie
Case Study: Spots in Envelope Grades Definition of Problem: Sheet spots occurring in finished products Resulting in rejected rolls and lost production Customer wishes to eliminate spots and improve machine cleanliness Production: 100 tons/day Furnish: 100% Old Corrugated Containers (OCC) Incumbent Deposit Control Program: Diatomaceous earth at 25#/T PAC at 11.25 #/T
Verifying the Problem: Visual Analyses The spots appeared as translucent flecks of material
Identifying the Cause: FTIR Spectroscopy Abs 0.2 0.1 Clear Spot in Yellow Envelope Grade 2916 2848 1733 1462 1373 1241 1162 1.0 Ethylene/Vinyl Acetate Hot Melt Adhesive 2918 Abs 0.5 2849 1737 1464 1238 1371 1.0 Cellulose Fiber Abs 0.5 1162 4000 3500 3000 2500 2000 1500 1000 Wavenumbers (cm1)
Identifying the Source: FTIR Spectroscopy 0.20 Clear Spot in Yellow Envelope Grade Abs 0.15 0.10 2916 2848 1733 1462 1373 1241 0.05 Seam Glue in Recycled Fiber 0.3 2917 Abs 0.2 2849 1733 1462 1377 1240 0.1 4000 3500 3000 2500 2000 1500 1000 Wavenumbers (cm1)
Creating the Solution: Product Additions Dry bags of smectite clay were added directly to the pulper at a dosage of 10.6 #/T Replaces diatomaceous earth at 25 #/T Smectite clay adsorbs colloidal dispersed glue particles A high charge density cationic polyamine was added to the suction side of the machine chest at a dosage of 2 to 4 #/T Replaces PAC at 11.25 #/T being added to top of machine chest
The Outcome... No spots observed in the sheet Reels passing quality inspections Furnish can handle increased amounts of gluecontaining waste paper Mill s furnish costs are decreasing (savings ~$200/T) Machine cleanliness has improved Fly roll / Press Roll observed to be cleaner than ever Microparticle usage provided additional benefits Tighter flocs improve sheet formation and drainage Steam usage reduced
Conclusions Hot Melt Stickies are a common contaminant in OCC furnishes Cause sheet spots and machine deposits Negatively impact total production costs Rejected reels Decreased production Extended shutdowns Costly transitions to cleaner fiber sources Using a smectite clay followed by a cationic polymer fixative can effectively handle hot melt stickies High surface area clay can adsorb/passivate stickies Cationic fixative ensures retention & removal of smectite/stickies complexes
Conclusions Laserlike focus on total production costs needed in today s climate Minimize sheet defects, deposits, downtime to maximize production budget Maximize lower cost furnish components to yield higher cash flow Promote sustainability efforts through optimal use of recycled fiber, energy/water conservation