Eliminating A Common OCC Stickies Problem

Transcription

1 Eliminating A Common OCC Stickies Problem Matthew A. Blazey Ciba Specialty Chemicals Water & Paper Treatment

2 Sustainability Day at Green Earth Elementary Please welcome the CEO of Reuseit Paper

3 Sally s Question... Why can t you use 100% recycled fiber?

4 D OH! If she only knew my hot melt stickies problems...

5 What Sally Doesn t See Hot Melt Stickies

6 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

7 Where Do They Come From? Common sources include old corrugated containers (OCC) and old magazines (OMG)

8 What is Their Impact?

9 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

10 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

11 Cedesorb Characteristics 1 micron Top View 300 nm nm thick

12 Adsorbing Colloidal Stickies Hot Melt Stickies + Smectite Clay

13 Retention of Adsorbed Stickies Onto Fines Smectite / Stickies Complex Fiber Fines + Polymer Fixative

14 Passivation of Macrostickies Macrostickie + Smectite Clay Passivated Macrostickie

15 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 #/T

16 Verifying the Problem: Visual Analyses The spots appeared as translucent flecks of material

17 Identifying the Cause: FTIR Spectroscopy Abs Clear Spot in Yellow Envelope Grade Ethylene/Vinyl Acetate Hot Melt Adhesive 2918 Abs Cellulose Fiber Abs Wavenumbers (cm1)

18 Identifying the Source: FTIR Spectroscopy 0.20 Clear Spot in Yellow Envelope Grade Abs Seam Glue in Recycled Fiber Abs Wavenumbers (cm1)

19 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 #/T being added to top of machine chest

20 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

21 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

22 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