Biodegradable Film Machine
PLA / PBAT Specialist Line

No — not reliably, and not without risking material degradation that will cause the film to fail compostability certification. The core problems are: a standard PE screw runs at too high a shear rate for PLA, causing localised overheating and chain scission; standard barrel temperatures are set 20–40°C above PLA's safe processing window; and standard die heads are not treated for the corrosive by-products of PLA thermal degradation.

Some operators report running low-PLA-content blends (<30% PLA) on PE machines with modified temperature profiles. However, the resulting film typically has reduced molecular weight, compromised mechanical properties, and will not pass EN 13432 or ASTM D6400 certification testing. For certified compostable film production, a dedicated machine is required.

Industrial compostable (EN 13432 / ASTM D6400) means the film degrades within 12 weeks at 58°C in a controlled industrial composting facility. This is the standard most plastic bag regulations accept as a compliant alternative to single-use PE bags.

Home compostable means the film degrades at ambient garden compost temperatures (typically 20–30°C) within a defined timeframe. This requires a different, more expensive blend formulation and is certified under separate standards (e.g. TÜV Austria OK compost HOME, AS 5810 in Australia). Standard PLA/PBAT blends do not meet home compostable standards without specific formulation work. Confirm your target certification with your resin supplier before making product claims.

The most common blend ratio for compostable bag film is 40–60% PLA / 40–60% PBAT, depending on the application. Higher PLA content increases stiffness and printability but reduces elongation and toughness — the film becomes more brittle. Higher PBAT content improves flexibility, puncture resistance and heat-seal performance but reduces stiffness and increases cost (PBAT is typically more expensive than PLA).

For shopping bags: 50/50 to 60/40 PLA/PBAT is a common starting point. For garbage and food waste bags requiring higher toughness: 40/60 PLA/PBAT or lower PLA ratios are more typical. For agricultural mulch film: formulation varies significantly by required degradation rate and soil conditions. LayerQuestar recommends working with your resin supplier to optimise the blend ratio for your specific application before committing to a production formula.

A drying system is not optional in practice — it is a prerequisite for consistent PLA/PBAT film production. PLA absorbs moisture from the atmosphere rapidly; even a few hours of open storage in a humid environment can raise moisture content above the safe processing threshold of 300 ppm. Processing undried PLA causes hydrolytic degradation during extrusion, resulting in film with reduced molecular weight, poor mechanical properties and failed compostability certification.

LayerQuestar offers an integrated dehumidifying drying system as an optional add-on, designed specifically for PLA/PBAT processing requirements. It can be ordered with the machine or added later. A standard hot-air dryer is not sufficient — dew point control is required to achieve <300 ppm moisture in PLA. Contact LayerQuestar for drying system specifications and pricing.

The single-layer machine uses one extruder to produce a single homogeneous PLA/PBAT blend layer. The blend ratio is fixed for a given run — you cannot independently optimise the outer surface and the inner seal layer. This is the right choice for most standard compostable bag applications where a single blend formula meets all requirements.

The 2-layer AB machine uses two extruders, each feeding one independent layer. Extruder A can run a PLA-rich blend (higher stiffness, better printability, anti-block additives) while Extruder B runs a PBAT-rich blend (higher flexibility, better heat-seal performance, slip additives). This gives you independent control over surface and seal performance — not possible on a single-layer machine. The 2-layer AB configuration is recommended when your product requires both good printability and strong heat-seal performance, or when you are producing bags for high-speed form-fill-seal lines.

The core machine platform is the same — single-screw, 32:1 L/D, PLA/PBAT-specific screw design. The differences are in the die head size, winding system and film thickness range. Mulch film machines use wider die heads (up to 550mm on the LQ-85-2200) and are configured for very thin gauge film (8–15 microns) with precise thickness uniformity across the full width. Bag film machines are configured for 15–40 micron film with standard winding.

If you need both bag film and mulch film, contact LayerQuestar — a single machine can be configured with interchangeable die heads to serve both applications, depending on the width requirements. [NEEDS CLIENT VERIFICATION — confirm interchangeable die head availability across mulch and bag film models]

PLA and PBAT resins are significantly more expensive than LDPE or HDPE on a per-kilogram basis. The resin cost premium varies by region and market conditions, but PLA/PBAT blends typically cost 2–4× more per kilogram than standard PE resins. [TIER 3 — verify current resin pricing in your target market]

This cost premium is the primary reason compostable bags are sold at a higher price than PE bags. In markets with plastic bag bans, the regulatory requirement removes the price competition with PE — buyers must purchase compostable alternatives regardless of the price difference. This is why regulation is the primary driver of investment in PLA/PBAT production lines.

Compostability certification (EN 13432, ASTM D6400, AS 4736) is applied to the finished film product, not the machine. The machine manufacturer does not provide or guarantee compostability certification — that is the responsibility of the film producer, based on the specific blend formulation, film thickness and production parameters used.

However, the machine directly affects whether the film can achieve certification. If the machine degrades the PLA during processing — through overheating, excessive shear or moisture-induced hydrolysis — the resulting film will have reduced molecular weight and will fail the biodegradation rate tests required for EN 13432 certification. A dedicated PLA/PBAT machine with correct temperature control and pre-drying is a prerequisite for producing film that can pass certification testing.