New Stabilization Package for Controlled Rheology Polypropylene Fibers (Benchmarked against Phenol & Phenol-free Systems) SPE International Polyolefins Conference 2012 J. Mara 1, H.-J. Kwon 2, J.-D. Kim 2, J. Bayer 3 & K. Keck 2 1 Songwon International Americas; USA 2 Songwon Industrial, South Korea 3 Songwon International, Switzerland Introduction to Auto-oxidation of Polyolefins Degradation of Polypropylene (PP) Classification of PP Fibers (by Songwon) Stabilization Requirements for PP Fibers Stabilization Strategies for PP Fibers Technical Benchmarking vs. Phenol-containing & Phenol-free Systems Summary Contents SPE International Polyolefins Conference 2012 Peroxy Radical Hydroperoxide Alkyl Radical Alkoxy Radical Hydroxy Radical Polymer None Radicalic Products Oxygen Heat Shear UV Metal Ion (Mn + ) Heat UV Simplified Auto-Oxidation Cycle of Polyolefins Introduction Concepts to Counter Auto-Oxidation of Polyolefins Free Radical Scavenging Phenolic Antioxidant + + Aminic Antioxidant + + Peroxide Decomposition Phosphite Antioxidant + + Thioester Antioxidant + + OH B A C OO* O*O* B A C OOH NHNH R OO* *N*N R OOH P OR RO OOH P OR O RO OR OH S RR OOH S R O R S R O R O OH S R O R OOHIntroduction SPE International Polyolefins Conference Peroxy Radical Hydroperoxide Alkyl Radical Alkoxy Radical Hydroxy Radical Polymer Oxygen Heat Shear UV Metal Ion (Mn + ) Heat UV Radical Scavenging HALS, Amine ? Radical Scavenging HALS, Amine, AO Radical Scavenging HALS, Amine, AO Auto-Oxidation Mechanism Thermo-Oxidation Peroxide Decomposition Phosphite, Thioester SPE International Polyolefins Conference 2012 Introduction PP is an unstable substrate Industrially unsuitable w/o stabilizers Undergoes uncontrolled thermo-oxidative degradation w/o stabilizers Polymerization, processing, & service life conditions can vary Degradation of Polypropylene SPE International Polyolefins Conference 2012 PP will undergo different Degradation Mechanisms: Processing/Conversion: Concentration [ROO*] < Concentration [R*] MW decreases; [Mw/Mn] narrows Disproportioning of Alkyl Radicals (formation of c=c) Storage/Service Life: Concentration [ROO*] >> Concentration [R*] MW decreases; [Mw/Mn] broadens Formation of Carbonyl Groups Different & Contradicting Stabilizer Reqirements Degradation of Polypropylene SPE International Polyolefins Conference 2012 Classification of Polypropylene Fiber PP fiber grades are supplied over a range of MWs depending upon processing & conversion characteristics as well as required properties of the application. Songwon classifies PP fiber grades by the conversion technology & by the presence (or absence) of peroxides for controlled degradation (Controlled Rheology). Monofilament & Tape grades have low MFIs which need to be maintained during compounding & conversion. Meltblown & Spunbond grades have MFIs that must be tailored in a post reactor operation via the use of peroxides (CR grades). Bulk continuous filament & Staple grades are available as either reactor grades or CR grades. SPE International Polyolefins Conference 2012 Classification of Polypropylene Fibers SPE International Polyolefins Conference 2012 Reference:E.P. Moore; Polypropylene Handbook; Hanser Publishers (1996) Monofilament Slit Tape Staple Fiber Continuous Filament Spunbond Meltblown Reactor grade Narrow Normal to narrow Normal to broad Normal Classification of Polypropylene Fibers SPE International Polyolefins Conference 2012 Reference:E.P. Moore; Polypropylene Handbook; Hanser Publishers (1996) Monofilament Slit Tape Staple Fiber Continuous Filament Spunbond Meltblown Can be cracked Reactor grade Narrow Normal to narrow Normal to broad Normal Classification of Polypropylene Fibers SPE International Polyolefins Conference 2012 Reference:E.P. Moore; Polypropylene Handbook; Hanser Publishers (1996) Monofilament Slit Tape Staple Fiber Continuous Filament Spunbond Meltblown Typically cracked Can be cracked Reactor grade Narrow Normal to narrow Normal to broad Normal 1-Step CR 2-Step CR Standard Post Reactor Extrusion SPE International Polyolefins Conference 2012 Stabiliser & Peroxide Addition for CR-PP WW Peroxide (mainly liquid) Stabiliser Single Additive, OPS or masterfluff Loss-in-weight feeder (Individual) additive streams Polyolefin bulk feed Polymer main stream High shear extruder Pelletizing & Storage Silo or discharge hopper P Storage tank Pump Separate Addition during Extrusion SPE International Polyolefins Conference 2012 Stabiliser & Peroxide Addition for CR-PP WW Peroxide (mainly liquid) Stabiliser Single Additive, OPS or masterfluff Loss-in-weight feeder Stabiliser stream (later) Polyolefin bulk feed Polymer main stream High shear extruder Pelletizing & Storage Silo or discharge hopper P Storage tank Pump Peroxide stream (first) Stabilization Requirements of PP Fibers SPE International Polyolefins Conference 2012 Excellent MW protection during compounding & conversion Principle reason for addition of processing stabilizer No interaction with peroxides (CR grades) Peroxide interaction leads to strong antagonism w/processing stabilizer Low initial color following compounding Low color development following conversion Low gas fade during conversion & storage Potentially negatively affected by primary AO Adequate storage stability (optional) Outdoor UV stability (optional) Easily adjustable by choice of HAS Other (registrations, cost, industrial availability) Stabilization Requirements of PP Fibers Stabilization Requirements of PP Fibers Performance requirements for PP fiber stabilization packages vary with the conversion technology & the need for CR grades. An overview of the importance of the various requirements for the different PP fiber grades is given below: SPE International Polyolefins Conference 2012 February 26 th - February 29 th, 2012 Stabilization Strategies for PP Fibers SPE International Polyolefins Conference Alternatives for PP Fibers SPE International Polyolefins Conference 2012 Selection Guide for PP Fiber Grades Recommendations are grouped around the conversion technology & corresponding importance of stabilizer requirements as captured in previous slide. Songnox 3016 Characteristics Songnox 3016 Characteristics New AO package for color critical applications, including: PP Fiber (Bulk Continuous Filament Reactor & CR; Staple Reactor & CR; & Spunbond applications) Polyolefin Film applications (Not covered today) Polyolefin Tape applications (Not covered today) Thin Walled Injection Molding (TWIM) applications (Not covered today) Provides an excellent balance between Processing Stability & Low Peroxide interaction. The interaction with peroxide is significantly reduced compared to Phenol containing systems (i.e., Songnox 321B) & Phenol-free systems, including: Irgastab FS 533 (Composition: FS042 + I C-2020) [1:10:3] Irgastab FS 102 (Composition: FS042 + I T-622) [1:2:1] Irgastab FS 410 (Composition: FS042 + C-944) [1:1] Performance data in PP homopolymer (gas phase) / MFI (230 C/2.16 kg) ~4 to 6 [dg/min] follows SPE International Polyolefins Conference 2012 Substrate:PP homopolymer (gasphase) MFI 230/2.16 ~ 4 to 6 [dg/min] Compounding: N 2, 190 215 o C, TS Criterion: MFI after compounding Stabilisation:500 ppm Ca-stearate ppm stabiliser Additivation:490 ppm PO-4 [2,5-Bis(t.-butylperoxy)-2,5-dimethylhexane] Stabilizer Interaction with Peroxide in CR-PP No additive Songnox 3016 GR Songnox 321B Irgastab FS 102 Irgastab FS 410 Irgastab FS 533 SPE International Polyolefins Conference 2012 Substrate:PP homopolymer (gasphase) MFI 230/2.16 ~ 4 to 6 [dg/min] Compounding: N 2, 190 215 o C, TS Exposure: 5hr at 60 o C under 5% NO x gas (KS K 0454) Stabilisation:500 ppm Ca-stearate ppm stabiliser Additivation:490 ppm PO-4 [2,5-Bis(t.-butylperoxy)-2,5-dimethylhexane] Criterion: Delta YI Low Gas Fading in CR-PP Songnox 3016 GR Songnox 321B Irgastab FS 102 Irgastab FS 410 Irgastab FS 533 SPE International Polyolefins Conference 2012 Substrate:PP homopolymer (gasphase) MFI 230/2.16 ~ 4 to 6 [dg/min] Compounding: N 2, 190 215 o C, TS Stabilisation:500 ppm Ca-stearate ppm stabiliser Additivation:490 ppm PO-4 [2,5-Bis(t.-butylperoxy)-2,5-dimethylhexane] Criterion: YI after compounding Low Initial Color in CR-PP Songnox 3016 GR Songnox 321B Irgastab FS 102 Irgastab FS 410 Irgastab FS 533 SPE International Polyolefins Conference 2012 Substrate:PP homopolymer (gasphase) MFI 230/2.16 ~ 4 to 6 [dg/min] Compounding: N 2, 190 215 o C, TS Stabilisation:500 ppm Ca-stearate ppm stabiliser Additivation:490 ppm PO-4 [2,5-Bis(t.-butylperoxy)-2,5-dimethylhexane] Criterion: YI after multiple extursion Pass 1 ~ 5 Low Color Development during Processing Songnox 3016 GR Songnox 321B Irgastab FS 102 Irgastab FS 410 Irgastab FS 533 SPE International Polyolefins Conference 2012 Stabilisation of Controlled Rheology Polypropylene Methodology Radar chart Relative scale:5 Best (outside) 4 3 Intermediate 2 1 Worst (inside, center) SPE International Polyolefins Conference 2012 Stabilisation of Controlled Rheology Polypropylene SPE International Polyolefins Conference 2012 Stabilisation of Controlled Rheology Polypropylene Unstabilised Controlled Rheology PP SPE International Polyolefins Conference 2012 Formulation: Stabilisation Strategy: Positioning: General Phenol Stabilizer System A A [Songnox 317B] Composition: 3 parts SN part SN1076 [Phenolic AO + Phosphite] synergism Standard phenolic AO Standard phosphite Partially optimised composition & ratio Standard AO package from IM or extrusion SPE International Polyolefins Conference 2012 Stabilisation of Controlled Rheology Polypropylene A [Songnox 317B] 1000 ppm SPE International Polyolefins Conference 2012 Formulation: Stabilisation Strategy: Positioning: General Phenol Stabilizer System B B [Songnox-321B] Composition: 2 parts SN part SN3114 [Phenolic AO + Phosphite] synergism Phenolic AO with reduced color formation Partially optimised composition & ratio Improved processing stability SPE International Polyolefins Conference 2012 Stabilisation of Controlled Rheology Polypropylene A [Songnox 317B] 1000 ppm B [Songnox 321B] 1000 ppm SPE International Polyolefins Conference 2012 Formulation: Stabilisation Strategy: Positioning: Phenol-Free Stabiliser System C C [Hydroxylamine + HAS / FS 410] Elimination of phenolic AO (color source) Processing stability based only on hydroxylamine No synergistic effect Conversion independant of service life Hyperactive processing stabiliser SPE International Polyolefins Conference 2012 Stabilisation of Controlled Rheology Polypropylene A [Songnox 317B] 1000 ppm B [Songnox 321B] 1000 ppm C [FS 410] 1000 ppm SPE International Polyolefins Conference 2012 Formulation: Stabilisation Strategy: Positioning: Phenol-Free Stabiliser System D,E D [Hydroxylamine + Phosphite + HAS / FS 102] E [Low hydroxylamine + Phosphite + HAS / FS 533] Elimination of phenolic AO (colour source) Kinetic balance Processing vs. Peroxide Synergistic effect Conversion independant of Service Life C System formulated with low level of hyperactive processing stabiliser SPE International Polyolefins Conference 2012 Stabilisation of Controlled Rheology Polypropylene A [Songnox 317B] 1000 ppm B [Songnox 321B] 1000 ppm C [FS 410] 1000 ppm D [FS 102] 1000 ppm E [FS 533] 1000 ppm SPE International Polyolefins Conference 2012 Formulation: Stabilisation Strategy: Positioning: New Color Critical Stabiliser System F [Songnox 3016 GR] Elimination of phenolic AO (colour source) Kinetic balance Processing vs. Peroxide Synergistic effect Conversion independant of Service Life No hyperactive processing stabiliser SPE International Polyolefins Conference 2012 Stabilisation of Controlled Rheology Polypropylene A [Songnox 317B] 1000 ppm B [Songnox 321B] 1000 ppm C [FS 410] 1000 ppm D [FS 102] 1000 ppm E [FS 533] 1000 ppm F [Songnox 3016] 1000 ppm SPE International Polyolefins Conference 2012 Summary PP in general must be stabilized during compounding, processing, storage, and service life. The stabilization of CR-PP during compounding and conversion is rather complex. While efficient protection of the PP is easily achievable via stabilizers with high molar activity & reaction kinetics, peroxides may also be added in order to degrade the PP in a controlled manner, yielding grades with lower MW & narrower MWDs. In this work, we introduced a powerful new AO package for CR-PP that provides excellent balance between processing stability, color suppression, and low peroxide interaction. While the scope of todays presentation was limited to CR-PP fiber applications, the technology is also applicable to other applications such as TWIM where low peroxide interaction and low color development are critical. SPE International Polyolefins Conference 2012