Novel Technologies to Produce Cellular Polymers with Tailored - - PowerPoint PPT Presentation
Hamburg-19 th -21 st November 2013 Novel Technologies to Produce Cellular Polymers with Tailored Cellular Structures and Properties C. Saiz-Arroyo 1,2 , J.A. de Saja 1 , M.A. Rodrguez-Prez 2 1 CellMat Technologies, Valladolid-Spain 2 CellMat
Technology and Innovation for Cellular Materials at Industry Service
1 CellMat Technologies, Valladolid-Spain 2 CellMat Laboratory-University of Valladolid, Valladolid- Spain
Hamburg-19th -21st November 2013
CELLULAR MATERIALS LABORATORY UNIVERSITY OF VALLADOLID- SPAIN
Established in 1999. International recognized laboratory in the area of cellular materials.
technology on cellular materials to industrial partners.
manufacturing better and cheaper materials using specific know-how.
formulations for foaming applications Established in October 2012. Spin-off company of the University of Valladolid.
SPECIFIC AND NOVEL KNOW-HOW AND TECHNOLOGIES ON ADVANCED CELLULAR MATERIALS
LICENSES TRANSFER AGREEMENTS
FLAME RETARDANCY
SOLID PLASTIC PARTS PRODUCERS
PROCESS & PRODUCT
BY BIOPLASTICS
FLAME RETARDANCY
FOAM PRODUCERS
0.75, (weight reduction lower than 25%)
THE PRODUCTION OF LIGHT-WEIGHT LARGE PARTS IS SOMEHOW LIMITED NOWADAYS
A NEW TECHNOLOGY TO PRODUCE LARGE LIGHTWEIGHT PLASTIC PARTS, WITH EXCELLENT SURFACE QUALITY USING SIMPLE AND CHEAP MOLDS, AND ADEQUATE FOR THE PRODUCTION OF SHORT SERIES.
Formulation of raw material Feeding raw material into a mold Heating to fill the mold Cooling and demolding
Polymer: Thermoplastics Additives: (Micro-nano, up to 80%) Blowing agent Self-bearing molds
LOW PRESSURES (lower than 30 bar)
“Carousel system”
Stages molding process is basically a free-foaming process using thermoplastics as raw materials, so it becomes strictly necessary to develop highly stabilized formulations. NON-STABILIZED MATERIAL STABILIZED MATERIAL
Possible to generate skin-core morphology.
advantages.
pressures, (lower than 30 bar). SHORT SERIES AT LOW COST.
60 mm.
(80%). Possible to use also recycled polymers.
59 cm
APPLICATIONS
ANY INDUSTRY USING PLASTIC AS RAW MATERIAL
STAGES MOLDING: A TECHNICAL & LOW COST SOLUTION
HIGH WEIGHT REDUCTIONS, UP TO 80% WEIGHT, RAW MATERIAL & COST REDUCTION SELF-BEARING & LOW PRESSURE MOLDS COST REDUCTION & LOW INVESTMENTS FOR IMPLEMENTATION NO INJECTION UNIT LARGE PARTS, GOOD SURFACE QUALITY NO SECONDARY PROCESSES & LESS DISCARDED PRODUCTS THERMOPLASTICS & ANY FILLER RECYCLED AND/OR HIGH FILLER CONTENT
LOWER COST PER PART (SHORT SERIES)
SEVERAL STRATEGIC SECTORS USE FOAMS AS STRUCTURAL ELEMENTS Panels or core of sandwich panels
homogeneity.
absorption must be avoided.
low densities.
world involved in its production.
halogenated products.
performance as technical polymers.
Production of a solid precursor Foaming of precursor material under controlled pressure and temperature in a closed mould Cooling of foamed material Mixing raw materials in a twin-screw extruder
THE PRESSURE APPLIED DURING THE FOAMING STEP SELF-EXPANDABLE MOULDS
control.
NON-CROSSLINKED FOAMED PRODUCTS AND AN INDEPENDENT CONTROL OF DENSITY AND CELLULAR
CELLULAR STRUCTURES APPROPIATE TUNING OF FOAMING PARAMETERS AND CHEMICAL COMPOSITION
cellular structure and high anisotropy ratios, (higher than 2).
ANICELL CC 180 Kg/m3 ANICELL CC 150 Kg/m3 Elastic Modulus (Mpa) 180 120 Collapse Stress (MPa) 2.8 1.6 Open Cell Content (%) < 20 < 20 Anisotropy Ratio 2.3 2.6
class of lightweight fire resistant cores and panels.
AniCell PP Flame Retardant core There is no flame propagation when it is directly applied to the material No FR PP core
Parallel to expansion direction
ANICELL OC ARE NOVEL MATERIALS THAT COMBINE HIGH SPECIFIC MECHANICAL PROPERTIES WITH AN OPEN CELL STRUCTURE: EXCELLENT STRUCTURAL FOAMS FOR ACOUSTIC ABSORPTION OR FILTRATION PURPOSES. BIMODAL & 100% OPEN CELL CELLULAR STRUCTURE ANISOTROPY RATIO: 2.3-2.5
Perpendicular
COMPRESSIVE MODULUS
Crosslinked PVC foams AniCell CC (closed cell) AniCell OC (open cell) Rigid PU
ANICELL products are FULLY RECYCLABLE The ICM route does not imply crosslinking of polymer matrix even when products with densities around 90kg/m3 are produced. MECHANICAL RESPONSE COMPARABLE to that of commercial products based on crosslinked PVC or rigid PU. ANICELL is based in a POLYMER, HIGH MELT STRENGTH POLYPROPYLENE, (Daploy WB135 HMS). Currently working in technical polymers, (SAN, PET) Possible to generate HALOGEN FREE FLAME RETARDANT products. The ICM route permits including high amounts of fillers, (up to 40-50%)
VERY LOW RELATIVE DENSITIES 0.01 < ρR < 0.1 LOW DENSITY CROSSLINKED POLYOLEFIN FOAMS FLEXIBLE POLYURETHANE FLEXIBLE FOAMS
applications, (sound absorption, filtration, seats and mattresses, …)
LOW DENSITY OPEN CELL POLYOLEFIN BASED FOAMS
BASE POLYMER
PRODUCTION
MICROSTRUCTURE & PHYSICAL PROPERTIES
OPENCELLMAT FLEXIBLE POLYURETHANE COMMERCIAL_CLOSEDCELL COMMERCIAL_OPENCELL
Two-steps compression molding process
cell foam, this is something between flexible polyurethane and commercial closed cell foams but with smaller holes in the walls.
Material Cell Size (μm) Tortuosity Flexible Polyurethane 355 1.76 Commercial Closed Cell 255
630 25.4 OPENCELLMAT 670 35.2 Microstructure of OpenCellMat foam is an hybrid between commercial open and closed cell materials with the particularity of a completely interconnected and high tortuous cellular structure.
II I I II III
I. Elastic Region II. Plateau Region
III
c
σ
COMPRESSION TESTS: STRESS-STRAIN CURVES
Compression tests up to 75% strain, strain rate 0.1s-1. 5 cycles without recovery time.
L.J. Gibson, M.F. Ashby. Cellular Solids: Structure and Properties. 2nd Edition, Cambridge University Press, United Kingdom, (1997).
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8
ELASTIC MODULUS (MPa) Elastic Modulus Cycle#1
COMPRESSION TESTS: ELASTIC MODULUS
FLEXIBLE POLYURETHANE COMMERCIAL_OPENCELL COMMERCIAL_CLOSEDCELL
OPENCELLMAT
BENDING OF EDGES STRETCHING OF CELL WALLS GAS CONTRIBUTION
Ef: Foam Elastic Modulus Es:Solid Elastic Modulus fs: Mass fraction in the struts P0: Pressure into the cells υ: Poisson’s ratio ρf:: Foam Density ρs: Solid Density C: Constant
OpenCellMat is stiffer than open-celled commercial products based on blends of LDPE & EVA or in PUF
L.J. Gibson, M.F. Ashby. Cellular Solids: Structure and Properties. 2nd Edition, Cambridge University Press, United Kingdom, (1997).
COMPRESSION SET
4 8 12 16 20 24 2 4 6 8 10 12 14
Remanent Strain (%) Time (Hours)
OpenCellMat Commercial Open Cell Commercial Closed Cell Flexible Polyurethane Remanent strain of samples has been measured after compressing them at 25% strain during 22
0.5 and 24 hours after removing the compressive force, (according to ISO 1856/80B standard)
L0: Initial thickness of the sample. L: Thickness of the sample after deformation, measured at different times.
OpenCellMat is a slow-recover material, with a behavior similar to viscoelastic polyurethane. This behavior is the direct result of its very tortuous cellular structure with very small holes in cell walls.
Thermal conductivity of samples has been measured at 25ºC, (according to UNE 12667)
Material Thermal Conductivity (mW/mK) Flexible Polyurethane 38.5 Commercial Closed Cell 37.8 Commercial Open Cell 37.5 OPENCELLMAT 38 λs : Conduction through solid phase λg : Conduction through gas phase λc : Convection λr : Radiation
THERMAL CONDUCTIVITY
Thermal conductivity of OpenCellMat is similar to the one exhibited by the other products. The presence of small holes in the walls is not enough to activate the convection mechanism and therefore conductivities of all materials are very similar.
THERMAL STABILITY
Dimensional stability of polyolefin based samples has been measured by subjecting them to 100ºC during 24 hours. L0: Initial thickness of the sample. L: Thickness of the sample after being @100ºC during 24h.
OpenCellMat exhibits a behavior similar to closed cell products. As cell opening takes place during the foaming step, no biaxial stresses remains in cell walls.
2 4 6 8 10 12 14
SHRINKAGE (%)
97%
OPENCELLMAT
COMMERCIAL CLOSEDCELL COMMERCIAL OPENCELL
Typical performance of an open cell foam, so better sound absorption capability than closed cell material. Higher absorption capability than flexible polyurethane and commercial open cell foams at low frequencies. At high frequencies, similar performance than polyurethane and higher than that of open cell foams.
1000 2000 3000 4000 5000 6000 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
Normal Incidence Acoustic Absorption Coefficient Frequency (Hz)
Flexible polyurethane Commercial Open Cell Polyolefin based Foam Commercial Closed Cell Polyolefin based Foam OpenCellMat
Normal incidence acoustic absorption coefficient has been measured in an impedance tube, Brüel & Kjaer model UA-1630. Frequency range: 500-6400 Hz. (ISO 10534-2)
CELLMAT TECHNOLOGIES S.L. CENTRO DE TRANSFERENCIAS Y TECNOLOGÍAS APLICADAS (CTTA) PASEO DE BELÉN 9A OFFICE 105 47011, VALLADOLID-SPAIN Phone:+34 983 189 197 c.saiz@cellmattechnologies.com www.cellmattechnologies.com
ACKNOWLEDGEMENTS