Uudet roll-to-roll pinnoitus- ja pintakäsittelymenetelmät pakkausmateriaalien valmistuksessa

Suomalaisen pakkaus- ja muoviteollisuuden tutkimus, kehitys ja aikaansaannokset 4.9.2013 Helsinki 1 Uudet roll-to-roll pinnoitus- ja pintakäsittelymenetelmät pakkausmateriaalien valmistuksessa Johanna Lahti Dr. (Tech.), Senior Research Fellow Tampere University of Technology Department of Materials Science Paper Converting and Packaging Technology

2 Sisältö Johdanto: Pakkausmateriaalikehityksen haasteita Pinnoitus- ja pintakäsittelymenetelmät: Plasma ALD (Atomic Layer Deposition) LFS (Liquid Flame Spray) Yhteenveto

3 Miten saavutetaan toimiva pakkaus? MATERIAALIEN KEHITYS Barrier, kuumasaumattavuus, hot tack, painettavuus, jne. PROSESSIEN KEHITYS -Materiaalien valmistusprosessit -Pakkauksen valmistusprosessit PAKKAUS ja sen ominaisuudet Tiiveys, avattavuus/ suljettavuus, ulkonäkö, jne.

4 Pakkausmateriaalikehityksen haasteita 1(3) - Pakkausmateriaalin määrän vähentäminen vs. Barrier- eli suoja- /tiiveysominaisuudet (vesihöyry, happi, rasva, etc.): Pienemmällä materiaalimäärällä saavutettava yhtä hyvät tai jopa paremmat ominaisuudet kuin nykyisillä ratkaisuilla Muovien ominaisuuksien kehittäminen (esim. nanotäyteaineet) Monikerros-/yhdistelmärakenteet (esim. paperi/kartonki & (bio)muovit & ohuet pinnoitteet) Uudet ohuet pinnoitteet (esim. ~ 10-100 nm) Yhdistetään uusia teknologioita jo olemassa oleviin: esi- ja jälkikäsittelyt, ohutpinnoitustekniikat

5 Pakkausmateriaalikehityksen haasteita 2(3) - Ympäristöystävällisyys: kierrätettävyys, kompostoitavuus, biohajoavuus Uusiutuviin luonnonvaroihin pohjautuvat raaka-aineet (etsitään vaihtoehtoja uusiutumattomille raaka-aineille) Uudet materiaalit kuten biopohjaiset materiaalit, biopolymeerit, jne. (tärkkelys, polylaktidi, etc.) ja niiden yhdistäminen kuitupohjaisiin materiaaleihin Alumiinin korvaaminen tietyissä käyttökohteissa uusilla barriermateriaaleilla Ref. Lahti, J., Pakkaus 1/2011

6 Pakkausmateriaalikehityksen haasteita 3(3) - Painettavuus: Pakkauksissa yhä vaativampia painoaiheita, paljon muuttuvaa tietoa, etc. Riittävän painoväriadheesion saavuttaminen Pintakäsittelymenetelmillä kuten liekki-, korona- ja plasmakäsittely (sekä näiden komibinaatiot) voidaan vaikuttaa painojäljen visuaaliseen laatuun ja hankauksenkestoon erityisesti muovipinnoilla. Ref. Lahti, J., väitöskirja, 2005; Tuominen & Lahti et al. JAST 24 (2010) 471-492

7 New R2R methods in our projects NANORATA: Liquid flame spray (LFS) nanocoating for flexible roll-to-roll web materials (Nesteliekkiruiskutus) (TEKES) RRALD: Roll-to-roll atomic layer deposition (ALD) process development (Atomikerroskasvatus) (TEKES) PLASMANICE: Atmospheric Plasmas for Nanoscale Industrial Surface Processing (EU/FP7) www.tut.fi/plasmanice NANOMEND: Nanoscale Defect Detection, Cleaning and Repair for Large Area Substrates (EU/FP7) http://nanomend.eu/

8 Nanotechnology Nanotechnology involves structures, devices and systems having novel properties and functions due to the arrangement of their atoms on the 1 to 100 nanometer scale Ref. www.tut.fi/plasmanice

9 Extrusion coating and laminating pilot line at TUT Pilot line at TUT (co)extrusion coating Dispersion coating (blade/rod) Cast film manufacturing Pre- and post-treatments (flame, corona, IR, UV) Relaxation unit for plastic film Max. web width 550 mm Max. line speed 500 m/min

Plasma surface modification PlasmaNice project 10 The main objective was to develop equipment for in-line atmospheric plasma deposition of functional nanoscale coatings on various fiber- and polymer-based substrates (paper, paperboard, plastic film). The approach exploited plasma-assisted solgel coatings and coatings applied on the substrates by plasma deposition. Plasma and nanotechnology were combined in order to develop innovative multifunctional coatings with a reduced environmental impact. The project used both LCA and risk analysis to evaluate and monitor the environmental performance and the safety aspects of the new processes and products. Ref. http://hlab.ee.tut.fi/plasmanice

11 Plasma surface modification Plasma is the fourth state of matter (solid, liquid, gas, plasma), and can be seen in nature e.g. as lightning A plasma is a (partially) ionised gas in which ions and electrons are present as well as radicals and molecules in an excited state Non-thermal plasmas based on atmospheric Dielectric Barrier Discharge (DBD) are typically used for surface treatment of polymers, metals and textiles Atmospheric Plasma Treatment (APT) equipment COST Corona and flame treatment Atmospheric Plasma Treatment (APT) Vacuum plasma ADDED VALUE Johanna Lahti Ref. AFS and VITO 5.9.2013

Atmospheric Plasma Treatment Corona & Flame Treatment 12 + operate in atmosphere (no vacuum/chambers), possibility to select treatment gas tailored surface chemistry + high energy densities effective treatment + operate in atmosphere no vacuum or chambers - operate in atmosphere fixed chemistry (air) - relatively low energy densities + longer lasting treatment - decay of treatment level (aging) + more uniform treatment - limited treatment uniformity, possible pin holes (corona) + no reverse side treatment (no - reverse side treatment blocking breakdowns through the material) problems (corona) + on-line, roll-to-roll process + on-line, roll-to-roll process - more complex process control and scale up more difficult + simple and acknowledged methods - certain treatment gases quite expensive + relatively low cost and high speeds

13 Plasma surface modification Plasma activation (pinnan aktivoiminen) - Functional chemical groups are created to the surface of the treated material For packaging materials e.g. to enhance adhesion properties, wettability and printability of surfaces Ref. Vangeneugden, D., 2007 Johanna Lahti 5.9.2013

14 Plasma surface modification Plasma deposition (ohuiden filmien kerrostaminen) - A completely new surface is created which enables the possibility to create barrier coatings from precursor such as e.g. sol-gels chemistry. - The desired surface properties can be obtained by injecting the precursor to the plasma discharge. - Plasma discharge is chemically very reactive environment which causes the precursor to be fragmented into reactive species. These reactive species react with each other and also with the surface to produce a coating to the surface of the treated substrate. - Depending on the chemistry used, various plasma deposited coatings can be produced, for example with grease/wv/oxygen barrier Ref. VITO

Untreated Corona Ar-Plasma 15 Example: UV inkjet printability of PP film Argon plasma treatment enhances ink wetting and uniformity of the printed lines In addition, adhesion properties of ink are improved PP film / 1 pixel line width / 300 dpi / UV ink Ref. Lahti, J. et al. 2011

Adhesion (0-5) Adhesion improvement by plasma surface grafting between PLA and paperboard 16 5 4 Plasma A + Plasma B (nitrogen) Plasma A + Plasma B (acrylic acid) 3 2 1 Plasma A + Plasma B (2- hydroxymethylacrylate) Plasma A + Plasma B (trimethoxysilylpropylethylenediamine) Plasma A + Plasma B (acetic acid) Corona Untreated reference 0 100 m/min (39,5 ± 1,9 g/m2) 150 m/min (27,7 ± 1,6 g/m2) 200 m/min (21,4 ± 1,3 g/m2) Line speed (coating weight) 250 m/min (16,9 ± 4,1 g/m2) 300 m/min (11,7 ± 3,3 g/m2) Ref. Lahti, J. et al. 2013

17 Plasma systems can be used for: Chemical functionalisation (~1-100 nm) O-containing groups N-containing groups F-containing groups SiOx-like coatings Acrylate/acrylic/ester/vinyl. functionalities Deposition of thin functional coatings (~10-500 nm) Adhesion Release Antibacterial Corrosion protection Reduced friction Barrier.. Ref. VITO

ALD (Atomic Layer Deposition) as part of a package 18 The targets for ALD technology as part of a packaging can be: Decrease the amount of other materials by extra ALD layer (if the barrier properties of the structure is the reason for thicker layer). Replace the whole layer in the package (e.g. aluminium foil) To create hydrophopic / hydrophilic surface Improve optical properties of the surface Concerning of barrier properties, the ALD process on moving substrate has been a success. The oxygen and water vapor barrier of paper / polymer / Al 2 O 3 -structures has improved significantly.

Atomic layer deposition (ALD) process 19 Purpose: thin, tight and stable coating from gaseous precursors. Main advantage: the conformality and uniformity which can be obtained regardless of the orientation or shape of the substrate; i.e., there are no pinholes in the film. In ALD process, thin films of material are deposited one atomic layer at a time. The ALD coating consists of several reaction cycles. One reaction cycle is able to achieve about 0.1 nm layer depending on the coating material and process parameters. Thickness of a typical ALD layer can vary from 1 to over 100 nm. Typically uses two precursors (TMA, trimethyl aluminium and water) to form film material, e.g. aluminium oxide (Al 2 O 3 ), which is the most studied material. Ref. Johansson, P., 2010

ALD is a chemical vapour deposition process based on chemical reactions on the surface of a substrate 20 Hydroxyl (-OH) substrate is exposed to first precursor, TMA (trimethylaluminum). Methane is flushed away from this reaction. H 3 C Al CH 3 CH 3 H O H O H O H O CH 4 H 3 C CH 3 Al H O O Dimethyl aluminum (-Al(CH 3 ) 2 ) substrate is exposed to second precursor, water. Methane is flushed away also from this reaction. H 2 O H C CH 3 3 H 3 C CH 3 H 3 C CH 3 Al Al Al O O O H C CH 3 3 Al O H 3 H C O Al O CH 4 H 3 C CH 3 Al O The Al 2 O 3 layer is ready. The process can now be started again from the beginning. H H O O Al O H O H O Al O H O H O Al O

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23 ANIMATION: ALD PROCESS by BENEQ Beneq WCS 500 Roll-to-Roll ALD system Available at: http://www.youtube.com/watch?v=xor8uomsvo4

24 Liquid Flame Spray (LFS) process Ref. Tuominen, M. et al 2013 Generate nanoparticles with flame process, i.e. liquid flame spray Particle material: TiO 2, SiO 2, ZrO 2, Al 2 O 3, Ag, Pd, Pt, Au, oxides of Na, Mg, Sr, Si, Ti, Al, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Mo, Ag, W, Pl, Nd, Pr, Yb, Se and mixtures/composites Particle size range: 2-200 nm Develop thin layer -coatings on e.g. fiber-based packaging materials Ref. Teisala, H., 2010

Liquid Flame Spray (LFS) process 25 Nesteliekkiruiskutuksessa vety-happiliekkiin syötetään nestemäinen lähtöaine, joka höyrystyy ja reagoi liekissä muodostaen nanohiukkasia. Pinnoitustilanteessa liekki suunnataan suoraan pintaan, johon kerääntyy liekissä syntyneitä nanohiukkasia. LFS BURNER NANOPARTICLES PRECURSOR SOLUTION HYDROGEN OXYGEN DROPLETS VAPOUR LFS PROCESS MOVING SUBSTRATE LFS COATING PARAMETERS LINE SPEED BURNER DISTANCE FEED RATE CONCENTRATION LEVELS NANOPARTICLE COATING 30 150m/min 4 25 cm 4 32ml/min 10 50 mg (atomic metal)/ml ROLL 1 ROLL 2 Ref. Teisala, H., 2010

26 Liquid Flame Spray (LFS) process Liquid Flame Spray (LFS) can be used to generate superhydrophobic CA > 150 (nano-titania, TiO 2 ) and superhydrophilic CA < 10 (nanosilica, SiO 2 ) surfaces onto different substrates like paperboard and paper TiO2 REFERENCE SiO2 LFS has great potential for industrial scale method because of its continuous nature, low coating amounts (30-50 mg/m2) and high line speeds The different amount of carbonaceous material on the TiO 2 and SiO 2 coatings is the main reason for the opposite wetting behaviour of the surfaces Ref. Teisala, H., 2010; Mäkelä, J., 2008.

Superhydrophobicity or superhydrophilicity for board Pigment coated board + LFS/TiO 2 Contact angle of water: LFS/TiO 2 : >150 LFS/SiO 2 : <10 Ref. Tuominen, M. et al 2013 Johanna Lahti

Functional nanoparticle coatings using Liquid Flame Spray (LFS) 28 LFS/TiO 2 coating properties: Gas permeable (breathable) Transparent Multifunctional: Superhydrophobicity/(philicity) Adjustable wettability by surface stimulation Self-cleanability Ref. Tuominen, M. et al 2013

ANIMATION: Water spread on LFS coated paperboard 29

30 Yhteenveto Atmosfäärisellä plasmakäsittelyllä voidaan muokata erilaisten pakkausmateriaalien pintaominaisuuksia kuten adheesio- ja painettavuusominaisuuksia Atmosfäärisellä plasmakäsittelyllä saavutetaan tiettyjä etuja perinteiseen koronaan verrattuna Ohut pinnoitustekniikoilla voidaan monipuolisesti muokata pintojen ominaisuuksia sekä luoda pinnoite-/päällystekerroksia, joilla on erittäin hyvät barrier-ominaisuudet Nanomittakaavan ohuet pinnoitteet mahdollistavat mm. pakkausmateriaalin kokonaismäärän vähentämisen menettämättä esim. barrier-ominaisuuksia Ohuilla pinnoitteilla voidaan saavuttaa hyvin erilaisia ominaisuuksia pinnoille, kuten kastuvuus, (super)hydrofobisuus/-fiilisyys Uusien materiaalien ja teknologioiden tutkimuksessa turvallisuus- ja ympäristönäkökulmat ovat tärkeä osa-alue (mm. LCA, RA)

31 References Teisala, H. et al., Surface and Coatings Technology 205 (2010) 436-445. Mäkelä, J. et al. 2008. Cameron, D. et al., MIICS 2010, Mikkeli. Johansson, P. et al., TAPPI Place 2010, Albuquerque, USA. Beneq, 2010. www.tut.fi/plasmanice/ http://nanomend.eu/ Tuominen, M. & Lahti, J. et al., JAST 24 (2010) 471-492. Tuominen, M. et al., Tappi 7th Int. Conf. on Nanotechnology for Renewable Materials, 2013, Stockholm. Lahti, J., Pakkaus 1/2011. Lahti, J. et al., Tappi Place 2011, Bregenz, Austria Lahti, J. et al., Tappi Place 2013, Dresden, Germany. Vangeneugden, D. & Rego, R., Tappi Place 2007, Athens, Greece. http://www.afs.biz http://www.vito.be

32 Thank you for your attention! Researchers in these projects at TUT tutkija Hannu Teisala tutkijatohtori Mikko Tuominen tutkija Petri Johansson tutkija Malin Kraft tutkija Hanna Christophliemk yliopistotutkija Johanna Lahti professori Jurkka Kuusipalo E-mail: johanna.lahti@tut.fi www-pages: http://www.tut.fi/mol Acknowledgements for EU/FP7, Tekes and all project partners!