Aqueous Nanocomposite Barrier Coatings A more sustainable option for high barrier flexible packaging

Transcription

1 Aqueous Nanocomposite Barrier Coatings A more sustainable option for high barrier flexible packaging Harris A. Goldberg; Carrie A. Feeney, and Michele Farrell InMat Inc. 216 Route 206 Suite 7 Hillsborough, NJ Phone: & Fax: hagoldberg@inmat.com

2 Outline InMat History Technology Platform and Approach Oxygen Barrier Performance Moisture Barrier Performance Laminate Barrier Performance Screening Results for Retort Summary and value proposition

3 InMat Inc. Leader in water based, environmentally friendly high barrier claypolymer nanocomposite coatings Product platform with commercial success & easily scaled to large volumes Current product lines use four different polymers and clays One component formulations that can be applied using standard coating methods (roll, spray or dip) Elastomeric Coatings High Barrier Coatings High Solid Paper Coatings Chemical protection Flexible packaging Barrier paperboard for food and juice cartons Sports balls Rigid packaging Grease resistant paper Specialty industrial Tires Air D-Fense 2000 Medical devices Nanolok PT ADV Nanolok PT E Nanolok EXC Nanolok PT MM Nanolok WR Nanolok PT HSC

4 Nanocomposite Barrier Coating Platform: Coating formulations using nanoclay & polymer dispersed in water Nanocomposite Barrier Substrate Aqueous Nanodispersed Suspension Once dry a thin coating provides extremely high barrier Reduced material costs Environmentally friendly / all ingredients have FDA food packaging status Polymer can be chosen to meet the requirements of the market Large (1-5 orders of magnitude) improvements in barrier properties over unfilled polymer Fundamentally different approach to clay polymer nanocomposites

5 Clay Polymer Nanocomposite Barrier: Basic Concepts Use clay minerals which are easily exfoliated in water to form 1-3 nm thick silicate sheets Impermeable sheets form tortuous path increasing barrier properties of polymer As concentration increases, a large fraction of the polymer will be near a clay surface May cause significant changes in permeability of polymer Key Variables Polymer permeability Plate aspect ratio Clay concentration Dispersion and microstructure Orientation

6 Nanocomposite Barrier Coatings Provide High Barrier in a Water-based, Environmentally Friendly, Coating Formulation Least O2 permeability (cc-mm/m 2 -day) 1000 LDPE 100 PP PLA 10 1 PET Nylon 0.1 PVDC PAN EVOH MXD LCP EVOH Nanolok TM PT Water Vapor Transmission (gm-mm/m 2 -day) Most

7 Optical Interference Image provides Surface Topography Map

8 Application Processes: Many can be used to coat films Flexible film: Many roll coating processes will work» Examples: Slot dye, curtain, flexo, and gravure We have used reverse offset gravure Enables simple thickness control by changing relative speed of film and gravure cylinder Film Offset roll Gravure roll

9 Correlation: Differential offset gravure versus coat weight (gsm) MVTR 38.5, (85% RH) PT ADV-3, PET 92g 21C, 56% RH Top Bottom Top Bottom DOG Coat weighthickness gsm ?? Coat 1.06 weight (gm/m2) Thickness 0.29 (µ) Thickness DOG % 1.3 There is a good correlation between the % offset, the coat weight (gsm) and the measured coating thickness.

10 Effect of Relative Humidity on Packaging Barrier Coatings Oxygen Permeability (cc um/m2 day atm) EVAL E PVDC EVAL F WR PTADV 0% 50% 65% 80% Relative Humidity PTADV-7 WR PVDC EVAL E EVAL F Nanolok coatings <1 micron thick will replace several microns of competitive materials.

11 InMat barrier coatings also provide large improvements in moisture barrier. Nanolok PT Control MVTR (gm/m 2.day) Coated Films 2-Level Model PLA 80g PET 48g BOPP 80g Coating thickness: ~ 0.7 µ

12 Flex Packaging Example Fewer layers in the final package results in cost reduction. Current Technology Total thickness: ~2.6 mils InMat Technology Total thickness: ~1.8 mils 0.5 mil PET 0.5 mil EVOH 1 mil PE 0.05 mil Nanolok 0.3 mil Adhesives 0.5 mil PET 1 mil PE

13 Performance of Flexible Laminates There are a large number of critical variables. Substrate x film Barrier coating Barrier x coating thickness x Adhesive Adhesive x thickness Laminating film Lamination conditions Temperature Pressure Time (rate) adhesive barrier adhesive barrier PE PET BOPP BOPP

14 Effect of Lamination Oxygen transmission rate reduced by a surprising amount. OTR (cc/m2 day atm) Thin Coatings of Nanolok WR Vary BOPP substrate & Adhesive Thickness (BOPP/WR-S/Toyo Adh/BOPP) BOPP 17 um BOPP 57 um BOPP 20 um control laminate Barrier coating thickness estimated to be ~ 0.2 microns Adhesive thickness (gsm) Large reductions in OTR after lamination occur on almost all samples PET, BOPP and variations in adhesives. The reductions are more pronounce for thinner coatings that contain more defects.

15 Peel Strength: Barrier coating thickness & adhesive coat weight are both important. 300 Effect of Coating Thickness & WATER based Adhesive Thickness on Peel Strength Using Nanolok WR and BOPP 57 um substrate (BOPP/WR-S/Liofol/BOPP) Peel Strength (g/inch) gsm 5 gsm 11 gsm 0.2 micron 0.45 micron 0.7 micron High adhesive coat weights decrease peel strength on the thin barrier coatings.

16 Feasibility for Retort Packaging Recent laboratory simulation demonstrated! 1 µm Nanolok 2 mil BOPP 5 µm Adhesive lamination 2 mil BOPP 2 mil BOPP Boiling water, 1 hr 2 mil BOPP 2 mil BOPP Barrier (cc/m2 day atm) Coated Film (Reverse gravure roll coated) Lab Lamination (with solvent adhesive) Simulated Retort (Boiling water, 1 hr) Clarity Good Excellent Excellent Adhesion n/a Good Good OTR of uncoated 2 mil BOPP ~1300cc/m2-day atm

17 Laminate Performance Thinner barrier coatings can be used in laminates due to the improvements in OTR after lamination. OTR not degraded after boiling in water for 1 hour. Peel strengths limited by cohesive strength. Large variation in cohesive strength of laminate depending upon: Barrier coating thickness Adhesive coat weight Substrate & surface treatment Type of adhesive It is likely that the laminating adhesive and/or the laminating process is reducing the peel strength further work is needed.

18 InMat Product Line: Several high barrier coatings available for flex packaging applications Product Permeability 1 (cc um/m2 day atm) MVTR 2 Adhesion 0% RH 65% RH 80% RH PT ADV PT ADV E EXC 1007V WR PET,PP,PLA All coatings can be applied directly to corona treated films without primer Coatings can be used in laminated and/or top coated structures Coatings can be used as base coat for ink, or as overcoat

19 Value Proposition Summary Barrier material cost savings Reduced package weight source reductions and disposal costs Reduce number of layers as Nanolok barrier can usually be applied directly to packaging film without an adhesive Water based coatings with neutral ph Standard application equipment for film Low cost spray equipment for rigid parts No solvents or hazardous materials Potential integration into printing and/or lamination process High oxygen barrier performance along with significant moisture barrier improvements. Potential for retortable and steam sterilized packaging

20 InMat has a line of unique, water based, barrier coatings suitable for flexible packaging and is seeking partners for full commercialization.