Running 100% PCR Blown Film
Why a bubble made of recycled polyethylene collapses, what converters do about it today, and which of the additive claims come with published evidence.
Blown film is where recycled polyethylene fails most visibly. A melt is extruded through an annular die and inflated into a bubble that is drawn upward, cooled by an air ring and collapsed into layflat film. The bubble is held up by the melt's own strength. Nothing else supports it. That makes the process an unusually direct test of whether a recycled resin has kept its molecular weight, and it is the application where converters notice recycled content long before a laboratory does.
What the bubble is telling you
A stable bubble needs melt that resists stretching more the faster it is stretched. Recycled polyethylene, having been through at least one extra heat history, has shorter chains and less long-chain branching, and behaves the opposite way: it thins where it is already thin. The symptoms follow in a predictable order.
- The bubble wanders, breathes or collapses, and line speed has to come down.
- Gauge drifts across the web, so the roll is out of tolerance even when the film looks fine.
- Gels and specks appear, from contamination and from partly unmelted material.
- Seal strength and puncture resistance fall, which is what the customer actually rejects.
Filtration and drying deal with the contamination. They do nothing for the molecular weight, which is the part the bubble is standing on.
The practical ceiling on recycled content
Nexam Chemical, which sells additives into this problem, characterises the market this way: most producers cap recycled content at 30% to 50% and absorb the waste and downtime as the cost of going recycled. That is a supplier's description of its own addressable problem rather than a survey, and we report it as such. We did not find an independent study putting a number on the ceiling.
For its own products the company claims stable blown film at around 2.5% masterbatch where production was previously not possible, using NEXAMITE R305 and NexCircle R401, which it describes as improving melt strength at lower dosage and enabling higher recycled content with stable processing.
Every claim on this page about what an additive achieves is the manufacturer's. No independent trial data has been published that we can find, and that absence is itself worth knowing when you are valuing the technology.
Why it is about to matter more
From 2030, Regulation (EU) 2025/40 sets a minimum of 35% recycled content for plastic packaging that is not contact-sensitive, averaged per plant and per year, rising to 65% in 2040. Most polyethylene film packaging falls in that category. A converter running at the low end of today's practical range is at the statutory floor in 2030 and far below it in 2040.
The supply is arriving at the same time. The EU recycled 67.5% of all packaging waste in 2023 but only 55% is required of plastic by 2030, and most member states are short of that, with rates from 23.0% in Hungary to 59.5% in Belgium. Collection improves, quality stays uneven, and the converter's problem becomes running film on whatever the stream delivers this month.
What we left out
The previous version of this page gave dosage ranges in weight percent, extruder temperature profiles, blow-up ratios and melt index targets. None carried a source. They are not repeated here. If you have line data or a published trial, send it and it goes on the page with the citation.
Sources
- Reactive Recycling, blown film for LDPE and LLDPE, for the recycled content cap and the masterbatch claim. The site is operated by Nexam Chemical.
- Nexam Chemical, recycled polyethylene processing, for the product descriptions.
- Regulation (EU) 2025/40, Article 7.
- Eurostat, packaging waste statistics, 2023 data.
Independent research, not affiliated with Nexam Chemical and not investment advice.