Fibre Applications
Fibre Applications Spunbond-Film-Composites Made From Renewable Resources Article contributed by Ralf Taubner Sächsisches Textilforschungsinstitut e.V. Department of Spunbondeds/Films Chemnitz, Germany www.stfi.de Properties of developed Spunbond-Film-Composites made from renewable resources The main goal of a recent research project was to develop a new production process for spunbond nonwovens made from PLA to promote the use of components for spunbond/film composites, and to seek further technical applications. The investigations carried out in this research project were particularly directed to further optimising the process developed in past investigations, and now with the help of an industrial sized laboratory, the researchers were able to investigate in particular filament fineness as well as basic weights, and to improve web uniformity. Finally, complete biologically degradable, extremely thin and light spunbond/film composites will be developed for hygiene and packaging applications. This composite will be distinguished by characteristics similar to conventional textiles regarding haptics and visual appearance without required increased and more expensive material usage. Textile PLA polymers were used for spunbond materials and PLA polymers plasticized by polyethylene glycol (PEG) were used for film production. All products within the hygiene range should have basic weights below 30gsm (grams per square meter) - similar to PP products. A special innovative feature was the combination of spunbond nonwovens and films made from biopolymers to produce new composite materials with improved permeability and barrier performance. First of all, PLA mono and bi-components were examined with regard to filament fineness and filament strength as well as tensile strength and elongation, depending on material throughput, cabin pressure, air vol- Tear growth resistance (acc. Trapeze) Nonwoven 70:30 --> c/s PLA 6202D:PLA 6751D 70:30 --> c/s PLA 6202D:PLA 6751D 70:30 --> c/s PLA 6202D:PLA 6751D modified PLA (with Polyglykol) modified PLA (with Polyglykol) modified PLA (with Polyglykol) PP-nonwoven /PE-Film Laminate Fa. Exten PP-nonwoven /PE-Film Laminate Fa. Clopay Film without nonwoven cd md cd md Water steam Composite permeability at 23°C adhesion Breaking load Breaking load E-Module E-Module Nonwoven Film and 100 % humidity thickness quality cN/cm N N N/mm 2 N/mm 2 g/(m 2 24h) 20 g/m 2 66020 4,9 8,2 7,1 443 990 194 20 g/m 2 61045 2,8 8,4 5,8 215 485 546 20 g/m 2 33808 0,8 - 2,5 6,9 - 11,3 5,0 - 6,7 239 - 278 602 - 856 148 - 207 20 g/m 2 66020 0,4 - 2,0 4,9 - 6,5 3,2 - 5,6 127 - 330 497 - 675 477 - 609 20 g/m 2 61045 0,8 5,7 3,5 160 205 441 15 g/m 2 66020 1,9 - - - - - - - - 19,5 9,9 134 349 51,4 - - - 15,3 8 48 282 56 66020 - 5 8,7 339 569 154 61045 - 6,6 8,7 230 294 541 33808 - 5,2 8,3 236 467 112 18 bioplastics MAGAZINE [05/11] Vol. 6
Cross section of composite made of 20gsm PLA-spunbond nonwoven + 22µm biopolymer film (engraving point) ume and filament speed. All filament variants were afterwards submitted to hot air and/or hot water shrinkage. The dependence of shrinkage behaviour on filament fineness was clearly proven. Finer filaments with higher stretching shrank less both in hot air and in hot water compared to thicker filaments with lower stretching. In case of thermal bonding all PLA spunbond nonwovens clearly differed depending on temperature and pressure as well as different basic weights. Some samples were only pre-bonded by calendering in order to be mechanically bonded by hydroentanglement or needle-punching in subsequent treatments. Comparison of the results with hydroentanglement showed that PLA based spunbond nonwovens can be more easily mechanically bonded than thermally bonded. Ultimately, PLA bi-component materials were thermally bonded with different biologically degradable films by means of calendering. These composites showed different characteristics with regard to tensile and tearing strengths, steam permeability, haptics and spunbond/film composite adhesion, depending on the adjusted process parameters at the calender process and on the manner of film feedin (inline and off-line procedure). The spunbond material made from modified PLA showed better haptics and/or softness compared to products made from standard PLA, however due to the level of polyglycol worse composite adhesion with films. Finally, composite adhesion could be significantly improved by Corona pre-treatment of the film and/or spunbond material. The main characteristics of the newly developed PLA spunbond/film composites were positively affected by optimization of process parameters, alternative engraving designs during calendering and optimized film formulation regarding composite adhesion and steam permeability. The author thanks the Federal Ministry for Economics and Technology, Germany for the promotion of this research project carried out by the EuroNorm Gesellschaft für Qualitätssicherung and Innovationsmanagement mbH within the programme „Promotion of research and development with growth carriers in disadvantaged regions “ (Innovative Wachstumsträger/INNOWATT). Meet us at FAKUMA 2011 Friedrichshafen / Germany Hall B3 – Booth 3119 Looking for environmentally friendly and energy-saving material handling of free-owing plastics? We offer individual components up to complete handling systems for: Conveying Drying Crystallizing Dosing Mixing Dyeing All from one source! All made in Germany! Cross section of composite made of 20gsm PLA-spunbond nonwoven + 20µm biopolymer film (engraving point) SOMOS ® MANN+HUMMEL ProTec GmbH Stubenwald-Allee 9, 64625 Bensheim/Germany Tel. +49 6251 77061-0 E-mail: info@mh-protec.com, www.mh-protec.com bioplastics MAGAZINE [05/11] Vol. 6 19
