As states and totally different authorities entitles switch to ban so-called “perpetually chemical substances,” supplies suppliers are working collectively to supply course of aids free of polyfluoroalkyl substances (PFAS), which is a significant problem amongst blown film and totally different polyolefin-based extrusion processors which have relied on these elements to take care of throughputs extreme.
According to Safer States, a nationwide alliance of environmental properly being organizations and coalitions working to safeguard people and the planet from “toxic chemical substances,” as of this writing 34 states have launched 294 insurance coverage insurance policies to protect people from these provides,” with 154 state insurance coverage insurance policies adopted in 30 states. As of April 2024, Safer States gives, some 30 U.S. attorneys fundamental have initiated litigation in the direction of the producers of PFAS chemical substances for contaminating water gives and totally different pure sources.
The matter is essential in extrusion, the place fluoropolymer-based polymer processing aids (PPA) have been used for a few years to control soften fracture by reducing the ground friction of flicks and totally different extrudates as they transfer by the use of the die physique and die lips, enabling processors to run at most throughputs. Transitioning to non-PFAS merchandise is not any small exercise and impacts your total supplies present chain in polyolefin extrusion. These PPAs are utilized by resin producers as they formulate polyolefin-specific extrusion grades, masterbatch suppliers and even processors themselves.
And the issue with eliminating “perpetually chemical substances” has been brewing for some time. Notes James Lloyd, director, new enterprise enchancment of Baerlocher USA’s Specific Parts Enterprise Unit, “PFAS has been beneath the environmental microscope given that late Nineteen Sixties — being current in water gives, fish and fowl. In 1998, the EPA was ‘first alerted to the risks’ of human-made “perpetually chemical substances” that assemble up in individuals and under no circumstances break down. And they also have an increasing number of flip right into a mainstream matter over the previous quite a lot of years.”
FIG 1 Soften fracture content material materials as a carry out of run time for varied polymer processing assist decisions with ZN catalyzed ethylene-hexene resin (density 0.918, soften index 1) extruded at a soften temperature of 420°F. The Baerolub AID 2201 has the quickest time to clear from soften fracture amongst all doable non-PFAS PPA candidates. Provide: Use of Non-Fluorinated Polymer Processing Help for Polyethylene Capabilities; researchdisclosure.com.
In polyolefin extrusion, PPAs are an vital supplies half to permit processors to take care of line costs at desired ranges and stay away from the need to all the time clear buildup on the die lips. Whereas additive suppliers had been investigating PFAS-free formulations, some blown film machine builders began investigating die-lip coatings that might supply further slip, though, as one put it, “Ultimately this can doubtless be a cloth supplier reply.”
A few 12 months prior to now, Baerlocher delivered to market a PPA geared towards serving to extrusion processors transition from per- and polyfluoroalkyl substances. Often called Baerolub AID, the additive targets blown film, pipe, and wire and cable, is claimed to be free of PFAS and siloxanes and appropriate with totally different elements utilized in film, just like anti-block or slip brokers. Baerlocher says Baerolub AID PPAs ship quick soften fracture clearing for metallocene and Ziegler Natta linear low-density polyethylene (LLDPE) and high-density polyethylene (HDPE), equaling or surpassing clearing situations of standard PPAs containing PFAS.
FIG 2 Soften temperature as a carry out of run time for the ZN ethylene-hexene resin (soften density 0.918; soften index 1) with out PPA, with the fluoropolymer PPA (left), and with the Baerolub AID 2201 (correct) fed in masterbatch type. Soften temperature displays a further pronounced decrease for the Baerolub AID 2201 PPA (about 7°F).
“Current and evolving European Union and U.S. Federal and state guidelines are forcing the plastic enterprise to seek for new alternate choices to PFAS-based processing aids,” notes Chad Harlan, Strategic Enterprise Unit Head, Baerlocher. “To meet this need, Baerlocher USA developed Baerolub AID PPAs that features proprietary, PFAS-free chemistry — a breakthrough that has propelled us right into a primary place throughout the PPA home. Our new merchandise check all the containers for effectivity, cost-effectiveness, regulatory compliance and reliable present. Upstream shoppers are enthusiastically adopting Baerolub AID merchandise and blown film converters routinely request our experience.”
Because of Baerolub AID PPAs are soluble throughout the polymer matrix, they’re acknowledged to produce greater haze effectivity than insoluble PFAS-containing PPAs and fantastic administration of frost line peak in blown film. Moreover, the additive can reduce die buildup and extruder stress. Because of they’re designed for max compliance with world meals contact guidelines, Baerolub AID PPAs are properly suited to functions along with polyethylene films for meals packaging and resins for potable water pipe.
Baerlocher USA rolled out two grades. Dr. Robert Sherman, the company’s technical director, notes that Baerolub AID 2201 provides processors the quickest time to clear the soften fracture in metallocene LLDPE. He gives, “In certain conditions, you would possibly wish to select Baerolub AID 2202, which presents fantastic soften clearing situations compared with standard PPAs.”
Baerolub AID merchandise may be discovered as neat elements (pastilles, rods, granules and powders), personalized blends and in masterbatch type. Baerlocher moreover provides shoppers regulatory expertise and help for lab and technical screening, blown film testing and preparation for manufacturing trials.
Resin Agency Verify Outcomes
Baerlocher ran worthwhile trials using the model new PPA at its laboratory-sized blown film line in Cincinnati, Ohio, and the company notes Baerolub has moreover been trialed at a handful of unnamed polyolefin producers of their labs, on production-sized gear. Efforts by Plastics Know-how to interact resin producers for an on-the-record dialogue of how the PFAS-free course of assist carried out weren’t worthwhile. Nonetheless, Plastics Know-how purchased a analysis titled “Use of Non-Fluorinated Polymer Processing Help for Polyethylene Capabilities,” that was posted in January 2024 by an unnamed polymer producer on the Questel web page researchdisclosure.com. The 13-page presentation could also be purchased for $45.
Whereas Baerlocher would not disclose its PFAS-free formulation, the analysis notes that Baerolub PFAS-free PPAs are based mostly totally on blends of vegetable lubricants and concludes: “(The elements) have demonstrated the flexibleness to chop again/eradicate soften fracture, lower die lip buildup and provide low cost in extruder torque.
FIG 3 Soften temperature as a carry out of run time for the ZN ethylene-hexene resin (soften density 0.918; soften index 1) with out PPA, with the fluoropolymer PPA (left), and with the Baerolub AID 2201 (correct) fed in masterbatch type. Soften temperature displays a further pronounced decrease for the Baerolub AID 2201 PPA (about 7°F).
“Whereas purposely meeting the technical requirements of a PPA, the non-PFAS formulations produced by Baerlocher moreover fulfill a broad spectrum of requirements required for the utilization of acknowledged merchandise in film functions that are destined for meals contact film functions. After exhaustive screening and quite a lot of evaluations, the Baerlocher merchandise had been the one non-PFAS PPAs that comfortable all the following requirements:
- Designed for max world meals contact approvals and meets present fashion and odor requirements
- Environmental points: not well-known on the “Document of Substances of Very Extreme Concern” (SVHC)
- Comparable processing advantages compared with current PFAS containing PPAs at economical loadings (1,000-2,500 ppm).
- No noticeable depositions (die lip buildup or leaching/mud formation) all through extrusion.
- Minimal modifications in effectivity properties of extruded film samples, along with optics (haze and gloss), printability after corona treatment and heat sealability effectivity
- Various product sorts (pastilles, prills, granules and additional) which can be launched neat or formulated as a masterbatch or as a preblend mix.
- Compatibility with totally different customary polyethylene elements (essential and secondary antioxidants, catalyst neutralizers, antiblock and slip elements).”
The anonymous resin supplier reported data from evaluations carried out utilizing a commercially on the market Ziegler Natta (ZN) ethylene-hexene LLDPE resin (soften indices of 0.918, 1.0) and a commercially on the market metallocene-LLPPE (m-LLDPE) resin (soften indices of 0.918, 1.0). The evaluations had been carried out using three methods of introducing the PPAs into the tactic: completely compounded resins containing 2,000 ppm of Baerolub AID 2201; the addition of Baerolub AID 2201 as a concentrated masterbatch (5% Baerolub AID 2201 in LDPE with 4% let down ratio); and the direct addition of 100% energetic Baerolub AID 2201 pastilles into the underside resin to understand a 2,000 ppm focus.
The resins utilized throughout the evaluations are commercially on the market and contained standard blown film additive packages (essential and secondary antioxidants, catalyst neutralizer/acid scavenger). They’d been run on a Hosokawa Alpine monolayer blown film line utilized for evaluating the effectivity of the Baerolub AID 2201 in the direction of an incumbent PFAS containing PPA3. The street had a die diameter of 250-mm; a die gap of two mm; a 75-mm extruder with a 30:1 L/D; and dual-lip air ring; and internal bubble cooling. The show pack configuration consisted of a 20-mesh sq. weave/30-150 Dutch Weave/20-mesh sq. weave
The street was run at a objective output of 400 lbs/hr using a blowup ratio of two.25, resulting in a film thickness of roughly 1.25 mil (31 mm). The experiments had been carried out to guage the variations in “time-to clear” of soften fracture throughout the film and totally different processing parameters (extruder rpm, motor load, soften temperature/stress, gauge variation).
Each evaluation adopted the protocol of evaluating a base resin with out PPA (administration) to a resin containing a fluorinated PPA and a resin containing Baerolub AID 2201.
FIG 4 Soften stress as a carry out of run time for the ZN ethylene-hexene resin (soften density 0.918; soften index 1) with out PPA, with the fluoropolymer PPA (left), and with the Baerolub AID 2201 (correct) fed in masterbatch type. The soften stress displays minimal enhance for Baerolub AID 2201 selection whereas there is a slight enhance over time for the fluoropolymer PPA.
“Time to clear” was outlined throughout the analysis as when soften fracture was decrease than 5% throughout the total circumference of the bubble. Examination of your total bubble circumference was carried out for each sample as that they had been collected at prescribed intervals. For consistency in determining the extent of soften fracture being seen, each of the film samples had been analyzed for soften fracture in the direction of a clear glass backdrop. Share soften fracture dedication protocol was established earlier to the beginning of the evaluations.
Each of the individual evaluations had been normally run for two hours to hint time to clear for soften fracture and to take a look at the soundness of the processing parameters. Extended runs (12-plus hours) had been moreover carried out to seek out out if there have been any indications of die lip buildup and to look at for deposits each on the best of the die and/or on the film coping with gear. Experiments had been moreover carried out with totally different non-PFAS PPAs that are presently being developed as potential replacements for the PFAS containing PPAs. These experiments had been carried out on the advisable ranges of the respective suppliers.
Essential Findings
What follows is a verbatim account of key findings printed throughout the analysis:
- Soften Fracture: Decide 1 illustrates the extent of soften fracture throughout the extruded film vs. the run time for the completely totally different non-PFAS PPA choices used throughout the evaluations along with the PFAS PPA selection. It was confirmed that the Baerolub AID 2201 has the quickest time to clear from soften fracture amongst all doable non-PFAS PPA candidates.
- Extruder RPM: This confirmed a small enhance for every the usual course of assist with fluorinated chemistry and non-PFAS Baerolub AID 2201 PPA evaluations when the additive variations had been launched. This enhance in rpm was attributed to the change in coefficient of friction (lubrication/slippage) throughout the extruder on account of addition of the PPAs.
- Motor Load: The motor load (Decide 2) displays barely further slippage for the Baerolub AID 2201 PPA compared with the usual course of assist.
- Soften Temperature: Equally, checks revealed (Decide 3) a further pronounced decrease for the Baerolub AID 2201 PPA (about 7°F) compared with the usual course of assist (about 3-4°F).
- Soften Pressure: The soften stress displays minimal enhance for Baerolub AID 2201 selection (Decide 4), whereas there is a slight enhance over time for the usual PPA.
- Gauge Variation: The gauge variation of the film displays an preliminary enhance for the usual PPA that dissipates over time (Decide 5), whereas the Baerolub AID 2201 gauge variation stays persistently low all through your total measurement of the evaluation. This comment will also be consistent with the excellence in mechanism of soften fracture elimination that is seen throughout the extruded film samples.
It was seen that the elimination of soften fracture for the usual PPA occurs in bands and/or stripes (reflecting the port line positions of the dies), whereas the elimination of soften fracture for Baerolub AID 2201 was seen as a gradual fading of soften fracture uniformly all through the film. This seen distinction in clearing mechanisms is attributed to the environment friendly dosing of Baerolub AID 2201 (2,000 ppm) being rather a lot higher than the usual PPA reply (500 ppm), which shows a weaker interfacial mechanism of the non-PFAS reply compared with fluorinated chemistry.
A trial was moreover carried out using two m-LLDPE ethylene-hexene resins (soften indices of 0.918, 1.0) in completely compounded formulations with each the Baerolub AID 2201 (2,000 ppm) or a fluoropolymer polymer processing assist (500 ppm).
In these runs, the street was started up and stabilized with the ZN ethylene-hexene resin, then transitioned after 1 hour of run time to the m-LLDPE resin with the Baerolub AID 2201. The run was continued at cost for an additional 3 hours. The “time to clear” soften fracture was spherical half-hour, and all the processing parameters continued to be regular over your total run interval. Following the three-hour run, the street was transitioned to a completely compounded m-LLDPE resin formulated with fluorinated PPA for the ultimate hour. The “time to clear” for this formulation took roughly one hour.
Comparable, to the runs with the ZN LLDPE resin, it was seen that the extruder rpm will enhance barely to maintain up the desired output for every the Baerolub AID 2201 and the fluoropolymer 0% containing PPA. This variation in rpm was attributed to screw slippage on account of introduction of the processing aids. The motor load was moreover consistent with slippage for every the Baerolub AID 2201 PPA and the fluorinated PPA compounded resins.
The soften temperatures elevated significantly (~ 60°F) in comparison with the startup resin as a result of the m-LLDPE catalyzed resins have a narrower molecular weight distribution, resulting in elevated shear heating. The rise in soften temperature is analogous for every the Baerolub AID 2201 PPA and the fluoropolymer PPA. With respect to the ZN LLDPE startup resin, the soften stress moreover displays an increase for every the Baerolub AID 2201 and the fluoropolymer PPA compounded throughout the m-LLDPE resin on account of enhance in soften viscosity.
FIG 5 Gauge variance as a carry out of run time for the ZN ethylene-hexene resin (soften density 0.918; soften index 1) with out PPA, with the fluoropolymer PPA (left), and with the Baerolub AID 2201 (correct) fed in masterbatch type. The gauge variation of the film displays an preliminary enhance for the fluoropolymer PPA that dissipates over time, whereas the Baerolub AID 2201 gauge variation stays persistently low all through your total measurement of the evaluation.
The gauge variation confirmed a considerable low cost for the m-LLDPE compounded with the Baerolub AID 2201 PPA all through the run time, whereas it displays fluctuations even on the end of the hour run for the fluoropolymer PPA. That’s consistent with the variations throughout the mechanisms for soften fracture elimination which is seen throughout the extruded film samples (as moreover seen for the ZN LLDPE runs carried out with PPA masterbatches). Whereas the soften fracture elimination occurs in stripes with the fluorinated PPA, (reflecting the port line positions of the die), the resin containing the Baerolub AID 2201 had a gradual fading of soften fracture, and the low cost occurred uniformly all through the circumference of the bubble.
The analysis concluded that:
- All through the context of the evaluations and compared with totally different non-PFAS containing polymer processing aids that had been evaluated, the Baerolub AID 2201 displays a clear profit for every ZN LLDPE and m-LLDPE film functions as a sensible polymer course of assist for blown film functions.
- The Baerolub AID 2201 demonstrated a significant enchancment in “time to clear” versus every the fluoropolymer PPA (as an illustration, 3M F5929M PPA) and the alternative non-PFAS PPAs evaluated throughout the experimental runs.
- The Baerolub AID 2201 was evaluated as a masterbatch, as a spotlight (pastilles) and as a completely compounded resin, and displays associated effectivity in each of the introduction methods as evidenced throughout the evaluations with every the ZN LLDPE and the m-LLDPE resins.
- Utilizing the Baerolub AID 2201 moreover ends in faster transitions with a lot much less purging being required to remove the PPA coating from die ground versus the complete totally different PPAs evaluated.
- Enhancements in gauge variation low cost of the bubble had been moreover seen compared with the prevailing PPAs that had been evaluated. This enchancment was on account of completely totally different soften fracture clearing mechanisms being employed. The Baerolub AID 2201 moreover has a further uniform elimination of the soften fracture compared with the port line elimination of soften fracture seen with the fluorinated PPA.
- All through the context of the evaluations, the Baerolub AID 2201 demonstrated the potential to modify the current fluoropolymer-containing PPAs whereas moreover satisfying a broad spectrum of requirements required for the utilization of acknowledged merchandise in film functions that are destined for meals contact film functions.