Sustainable Nonwoven Materials by Foam Forming … Nonwoven Materials by Foam Forming Using...
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Transcript of Sustainable Nonwoven Materials by Foam Forming … Nonwoven Materials by Foam Forming Using...
Sustainable Nonwoven Materials by Foam Forming Using Cellulosic Fibres and Recycled Materials
Aachen Dresden International Textile ConferenceAachen, 27.-28.11.2013Pirjo Heikkilä, Petri Jetsu, Karita Kinnunen, MarjoMäättänen, Kyösti Valta & Ali HarlinVTT Technical Research Centre of Finland
204/12/2013
Contents
Background Our approach Foam forming method Textiles from recycled cardboard Conclusions
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Background
Textile processing path is complex including water and energy intense steps and use of various chemicals Sustainability issues with
textile processes Some chemicals harmful for
people and environmentWater purification needs
and waste waters Large energy use e.g.
due to drying
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Background
World textile fibre consumption(70 million tons/year, 2010) Synthetics ~60% Cotton ~33%Man-made cellulosics ~4% Others (natural fibres other
than cotton ~3%) Sustainability issues with certain fibres Synthetics – oil based raw material Cotton – environmental issues: water use and chemicals Viscose –use of CS2 in process
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Our approach
Sustainability issues of nonwoven materials can be considered in processing as well as in raw material choice. Our process:
1. Foam forming instead of wet-laying → less water, less energy, excellent formation
2. Use of cellulose carbamate instead of viscose process→ no need for carbon disulfide (toxicity &
environmental risks)3. Use of recycled cardboard as raw material for
cellulosic→ use of recycled instead of virgin/genuine cellulose
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Foam forming in general
Foam as transport media instead of water: fibres and additives mixed with foam Foam consists of water,
foaming agent and air (typical air content 50-70%) Air bubbles prevent
flocculation of fibres
In paper processing significant resource savings (raw material, drying energy and chemical costs) with foam forming technology.
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Foam forming as textile processing method
Advantages over traditional forming and other textile methods: Possibility to adjust porosity and bulkiness in forming. Less water compared to wetlaying → less energy in drying and
transport. Possibility to use longer fibres compared
to wetlaying and airlaying. High forming consistency compared to
wetlaying. Good formation, more homogeneous
compared to other nonwovens and textiles. Better productivity compared to most other
textile processes.
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Foam forming / laying – research environments
Handsheet formers Small-circulation device ‘KISU’
SUORA-research environment
Sample size 250*380 & 500*500 mm. Laboratory pressing & drying
Web width 120 mm.Laboratory pressing & drying
Web width 250 mm. Reeled sample & offline cylinder drying
Web speed - 300 m/min (foam)300 m/min (water)
~1000 m/min (foam)2000 m/min (water)
Amount of fibers
>Few grams > 5 kg > 300 kg
Layered products
From one upto five 3-layers (foam)Single layer (water & water)
Single layer (foam)3 layers (water)
Forming geometry
1-sided dewatering 1-sided dewatering Fourdrinier / hybrid / gap
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Foam laid products from commercial fibres
100 % Viscose (9 mm)60 g/m2
Viscose (9 mm)-bicomponent(PES/PE, 5 mm) 1:1 mixture
60 g/m2
Viscose (9 mm) -pine kraft 1:1 mixture
60 g/m2
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Textiles from recycled cardboard
Recycled cardboard (or paper)
PurificationCarbamatizationDissolution
Cellulose carbamate solution
Wet-spinning
Cellulose fibres
Foam forming
Nonwoven web
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Purification steps of recycled fibres
Fines removal DDJ
For RCF Board Cooking and O-delign.
Cold caustic extraction CCE
Bleaching DEpDP
Enzyme Treatment EG
Acid Washing A
Ash removalP: 2 % => 0.6 %B: 7.9 % => 1.4%
Lignin removalB: 16.2% => 5%
Hemicelluloses removalP: 21 % => 9 %B: 21 % => 8%
Brightness and purity
Reactivity and viscosity adjustment
Metal removal
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Cellulose carbamate process
Ref RCF paper RCF board
DP initial
DP CCA
CCA (%) final
Ball visco.(s)
N (%)
Ref Domsjö 780 300 6.1 40 1.2RCF Paper 600 290 5.6 19 2.2RCF Board 290 250 6.3 22 1.5
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Cellulose carbamate process (in viscose process line)
CCA dissolving
CCA stabile at dry stateSolution 4-10% in NaOH 8% solution chilled to +5°C for
long time storage
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Wet-spinning and properties of fibres
Stretch ratio%
Titre dtex
TenacitycN/dtex
Elongation%
ModuluscN/dtex
Ref Domsjö 100 2.0 2.1 15.2 74.5RCF Paper 120 1.9 2.1 16.2 72.5RCF Board 120 2.2 2.0 15.4
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Foam laying of wet-spun fibres
CCA fibres were cut to 13 mm or 25 mm length and bundles opened using laboratory scale carding device. The quality of the sheets formation depended on how well the
carding was done.
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Techno-economic feasibility of dissolving pulp process
-1000
100200300400500
RefSWDP
RefHWDP
RCFBoard
RCFPaper
Waste 2 2 2 2Utilities 5 5 3 12Chemicals 32 24 25 49Wood and RCF 341 289 223 260By-products -80 -66 6 5Tot. 300 254 259 328
[€/a
dt]
The total costs of RCF board over 15 % lower than the reference SW and same as reference HW. Reference pulp mill Nordic
prehydrolysis kraft pulp mill producing 2000 adt/day of pulp.
The fibre raw material cost was dominating factor for all cases covering 80% of total costs. Especially the price of RCF fibres has been fluctuating.
Revenues from by-products were deducted from the costs only with reference mills.
Techno-economic feasibility study is based on the mass and energy balances of process as well variable production cost estimates.
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Summary and conclusions
Foam laying is viable method for more sustainable, and presumably also economically feasible, nonwoven production. Use of recycled raw material interesting option also from
economical point of view. Cellulose carbamate technology can replace viscose
technology – also mechanical properties similar than those of commercial fibres. The production of the staple grade fibres from recycled
paper and board using carbamate technique was proven to work with rather good economic - variable costs of dissolving pulp produced from board was 15% lower than reference softwood pulp.
1804/12/2013
Senior scientist Pirjo Heikkilä, Dr. Tech. VTT Technical research centre of Finland
+358 40 689 [email protected]
Thank you for your attention!Questions? Acknoledgement
Tampere University of Technology
Wet-spinning
1904/12/2013
VTT creates business from technology