0
Extrusion Lamination
   of Poly-woven Bags

     An over-view of primers and
                resins



Jessica Bodine – Mi...
The Science of Adhesion

    Two Types of Bonding
           Chemical
             &
          Mechanical
Polypropylene Woven:
Basic Lamination –
“Mechanical” Adhesion



                PP Woven

               PP Extrudate
   ...
What is a Bag With-out printing?
 Surface Printing does not interfere with
 extrudate adhesion
 Benefits of reverse printi...
Reverse Printed Lamination



             PP Woven

            PP Extrudate
INK

             OPP Film
What happens next?
  Ink does not stick to OPP film OR extrudate:
      Failure will be at weakest interface
Ink Needs “Chemical” Adhesion
          Corona not only provides wet-out of ink –
          but chemical “anchors” for ink...
Corona Treatment

               Watt-Density = Power /(area x time)
                          US Units: W/(ft2/minute)
  ...
What Happens next?

          Ink now sticks great to OPP:
Makes ink/extrudate interface appear even weaker
Two part Solution:




    Part 1: Primers
What is a Primer?

 Surface modifier
                increases energy
                cleans, removes contaminants
       ...
Mica Water-Based Primers for Film
When Using Polyolefin Extrudate
 Cross-linked (!) Polyethylene Imine (PEI)

 Mica A-131-...
How do you apply a Primer?


   • Smooth Roll Applicator
   • Gravure or Anilox Applicators
   • Mayer Rod (Wire Wound) Ap...
How do you apply a Primer?

             Smooth Roll Applicator
   Hard rubber impression roll
            • 90 durometer
...
How do you apply a Primer?
  Smooth Roll (3) Applicator (Indirect)
      Web
                                 Backup Roll
...
How do you apply a Primer?

     Smooth Roll Applicator (Direct)

  Web                            Rubber Impression Roll
...
How do you apply a Primer?
      Direct Gravure Applicator


     Web
                               Backup Roll
     Grav...
How do you apply a Primer?
  Gravure Applicator – Specifications
       To deliver target wet/dry weight;
    Specify a ce...
How do you apply a Primer?
    Gravure Applicator – Materials
     •Ceramic
        • Long service life
        • Prone to...
How do you apply a Primer?
            Mayer Rod Applicator
 Wire Wound Coating Rod




 Space between wire windings deter...
How do you apply a Primer?
Steps to follow;
      1)Treat
                Corona, Flame
      2)Apply
                Smoo...
How do you apply a Primer?

               Ensure Proper Coatweight
    Recommended Range is: 0.02 – 0.03 dry lbs/ream
   ...
How do you apply a Primer?
                  Ensure Complete Drying
a)   Drying MICA A-131-X is relatively easy.

b)   Ove...
Primers and reactive sites
 Primer adds reactive sites to the ink?
    = primer




 But what about the extrudate?

      ...
Part 2



The Resins
Polyethylene
 Oxidized in extrusion process
 Reactive sites form chemical bonds with
 primers
 Does not stick to polypropy...
Polypropylene
 “Inert” chemical nature – does not
 oxidize during extrusion
 No reactive sites for chemical reaction
 (ink...
Maleic Anhdride Adhesive
Resins
 Known to give adhesion as tie-layer
 (costly and requires co-extrusion)
 Mica has discove...
Maleic Anhydride Concentrate
Considerations
 Backbone (concentrate base resin)
 needs to be compatible with resin to be
 e...
Materials


   Resin 1: DuPont Bynel 50E803
   Resin 2: Chemtura Polybond 3000
   Resin 3: Arkema Orevac CA 100


 Concent...
Finished Structure

   = primer                   = MAH resin




  Chemical reactions at every interface = destructive bo...
Steps to Making Poly-woven
Lamination
1.   OPP with 54 or higher dyne level
2.   Print
3.   Prime with 0.02 dpr cross-link...
Some Additional Considerations
 PP base resin (extrusion grade!)
 •   Homo-polymer
 •   Co-polymer
 •   Added polyloefin f...
Experimental

Primer         Resin              Bonding
Yes            PP only            zero
No             PP + resin o...
Discussion of Results
 Strength of structure will be strength of
 the weakest interface
 In this case – ink cohesion was w...
Contact Information
   Jessica Bodine
   Mica Corporation
   9 Mountain View Drive
   Shelton, CT 06484
   (203) 922-8888
...
Upcoming SlideShare
Loading in...5
×

Extrusion lamination of poly wovenbags[1]

1,732

Published on

Published in: Education
0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total Views
1,732
On Slideshare
0
From Embeds
0
Number of Embeds
0
Actions
Shares
0
Downloads
59
Comments
0
Likes
0
Embeds 0
No embeds

No notes for slide

Transcript of "Extrusion lamination of poly wovenbags[1]"

  1. 1. Extrusion Lamination of Poly-woven Bags An over-view of primers and resins Jessica Bodine – Mica Corporation IOPP Technical Bag Committee Meeting January 20th, 2009
  2. 2. The Science of Adhesion Two Types of Bonding Chemical & Mechanical
  3. 3. Polypropylene Woven: Basic Lamination – “Mechanical” Adhesion PP Woven PP Extrudate OPP Film
  4. 4. What is a Bag With-out printing? Surface Printing does not interfere with extrudate adhesion Benefits of reverse printing: • Gloss • Clarity • Scuff Resistance • Moisture Resistance
  5. 5. Reverse Printed Lamination PP Woven PP Extrudate INK OPP Film
  6. 6. What happens next? Ink does not stick to OPP film OR extrudate: Failure will be at weakest interface
  7. 7. Ink Needs “Chemical” Adhesion Corona not only provides wet-out of ink – but chemical “anchors” for ink PP Woven PP Extrudate Ink Treated OPP
  8. 8. Corona Treatment Watt-Density = Power /(area x time) US Units: W/(ft2/minute) [KW setting x 1000] / [Line Speed (ft/min) x width (ft)] Example: Treater output = 3.0kW; line speed = 450 fpm; Treater width = 5 ft The watt-density is: (3.0 x1000)/(450 x 5) = 1.7 W/(ft2/min) Important: You must determine optimum watt-density for each film and for each set of running conditions. Some starting suggestions: BOPP films: 3.0 – 4.0 WD OPET films: 1.5 – 2.0 WD BON films: 0.5 – 1.5 WD (metric units are factor of 10 higher)
  9. 9. What Happens next? Ink now sticks great to OPP: Makes ink/extrudate interface appear even weaker
  10. 10. Two part Solution: Part 1: Primers
  11. 11. What is a Primer? Surface modifier increases energy cleans, removes contaminants adds reactive sites Facilitates “wet-out” of secondary coating Provides adhesion between substrate and coating/extrudate Enhances chemical resistance
  12. 12. Mica Water-Based Primers for Film When Using Polyolefin Extrudate Cross-linked (!) Polyethylene Imine (PEI) Mica A-131-X – 5% solids, standard of the industry, pH 10.5, easy to use and clean-up, components are FDA CFR 175.105 Mica H-760-A – 12% solids, less shipping, more attention to dilution, easy clean-up and components are FDA CFR 175.105
  13. 13. How do you apply a Primer? • Smooth Roll Applicator • Gravure or Anilox Applicators • Mayer Rod (Wire Wound) Applicator
  14. 14. How do you apply a Primer? Smooth Roll Applicator Hard rubber impression roll • 90 durometer • Does not have to be undercut Low compression • Approximately ¼ inch (6 mm) Vary application weight by; • Applicator roll speed • Primer dilution recipe
  15. 15. How do you apply a Primer? Smooth Roll (3) Applicator (Indirect) Web Backup Roll Transfer Roll Flooded Nip Pick-up Roll Flooded Nip Primer Reservoir
  16. 16. How do you apply a Primer? Smooth Roll Applicator (Direct) Web Rubber Impression Roll Flooded Nip Smooth Rubber Pickup Roll Primer Reservoir
  17. 17. How do you apply a Primer? Direct Gravure Applicator Web Backup Roll Gravure Chambered doctor Roll > blade Primer reservoir
  18. 18. How do you apply a Primer? Gravure Applicator – Specifications To deliver target wet/dry weight; Specify a cell volume - not a line count. Example: PEI type primer for film substrate Dilute primer 1:1 Apply 0.02 dry lbs/ream Many possible configurations: Direct forward gravure, 180 pyramid, 3.2 bcm Direct forward gravure, 360 pyramid, 3.7 bcm
  19. 19. How do you apply a Primer? Gravure Applicator – Materials •Ceramic • Long service life • Prone to clogging • Add 15 – 20% cell volume to compensate •Chrome • Easier to clean • Shorter service life
  20. 20. How do you apply a Primer? Mayer Rod Applicator Wire Wound Coating Rod Space between wire windings determine amount delivered (0.003" - 0.060" in 0.001" increments).
  21. 21. How do you apply a Primer? Steps to follow; 1)Treat Corona, Flame 2)Apply Smooth roll, Gravure, Flexo 3)Dry Hot, circulating air; infrared Flame (paper only)
  22. 22. How do you apply a Primer? Ensure Proper Coatweight Recommended Range is: 0.02 – 0.03 dry lbs/ream % Solids by refractometer or gravimetric oven test. Monitor coatweight by consumption of primer. Use Mica “Color-Chip” Stain Test Primer coating uniformity; a) Water soluble optical brightener with a UV lamp. b) Eosin stain testing and “Color-Chip”/Colorimeter.
  23. 23. How do you apply a Primer? Ensure Complete Drying a) Drying MICA A-131-X is relatively easy. b) Oven airflow is equally important as the exit web temperature. c) Recommended Exit Web Temperature: 140oF – 180oF
  24. 24. Primers and reactive sites Primer adds reactive sites to the ink? = primer But what about the extrudate? PP Extrudate
  25. 25. Part 2 The Resins
  26. 26. Polyethylene Oxidized in extrusion process Reactive sites form chemical bonds with primers Does not stick to polypropylene woven (will stick the HDPE though) Does not have strength, heat and grease resistance of polypropylene
  27. 27. Polypropylene “Inert” chemical nature – does not oxidize during extrusion No reactive sites for chemical reaction (inks OR primers) Does “mix” with PP poly-woven (mechanical) Tough, strong, excellent moisture and grease resistance
  28. 28. Maleic Anhdride Adhesive Resins Known to give adhesion as tie-layer (costly and requires co-extrusion) Mica has discovered that “MAH” concentrates can be blended in polypropylene Mica water-based primers have perfect chemistry for reaction with MAH – serves as the reactive site for the extrudate
  29. 29. Maleic Anhydride Concentrate Considerations Backbone (concentrate base resin) needs to be compatible with resin to be extruded Needs 1-2% maleic anhydride (or equivalent) in order to be diluted to 0.2% total anhydride content in final blend Blending 10 – 20% of material must not interfere with extrusion properties (melt strength, neck-in etc.)
  30. 30. Materials Resin 1: DuPont Bynel 50E803 Resin 2: Chemtura Polybond 3000 Resin 3: Arkema Orevac CA 100 Concentrates were blended into polypropylene so that the final MAH concentration was 0.20%
  31. 31. Finished Structure = primer = MAH resin Chemical reactions at every interface = destructive bonding
  32. 32. Steps to Making Poly-woven Lamination 1. OPP with 54 or higher dyne level 2. Print 3. Prime with 0.02 dpr cross-linked PEI 4. Dry thoroughly 5. Extrude with PP + 15-20% MAH concentrate 6. Laminate PP woven
  33. 33. Some Additional Considerations PP base resin (extrusion grade!) • Homo-polymer • Co-polymer • Added polyloefin for run-ability • Final mix should be at least 70% PP Slip additives in OPP film Cohesive strength of the ink • Ink chemistry • Coverage • Drying • In-line/out of line priming
  34. 34. Experimental Primer Resin Bonding Yes PP only zero No PP + resin one zero Yes PP + resin one 60% ink removal No PP + resin two zero Yes PP + resin two 80% ink removal No PP + resin three zero Yes PP + resin three 60% ink removal
  35. 35. Discussion of Results Strength of structure will be strength of the weakest interface In this case – ink cohesion was weakest Primer can be used under the inks when this is the issue (still needs corona treatment) OPP/”T”/primer/ink/primer/PP+MAH/woven
  36. 36. Contact Information Jessica Bodine Mica Corporation 9 Mountain View Drive Shelton, CT 06484 (203) 922-8888 Jbodine@mica-corp.com THANK YOU!
  1. A particular slide catching your eye?

    Clipping is a handy way to collect important slides you want to go back to later.

×