Bio-polyolefins 2002D Starch-Based Clear Extrusion Compostable Grade is a pelletized thermoplastic compound supplied for cast film, blown film, and sheet extrusion. The material is formulated with starch-based domains dispersed in a polyolefin matrix. The starch phase provides enzymatic access during industrial composting, while the polyolefin phase contributes melt processability, seal strength, and web handling. Product-specific lot documentation should be obtained from the supplier before line trials because starch dispersion, moisture uptake, and additive levels vary between production campaigns.

Model designation 2002D identifies the grade as a clear extrusion product within the bio-polyolefin series. Unlike conventional polyolefins, the material is designed to fail compostability screening only when starch domains remain accessible and oxidative fragmentation of the polyolefin is not inhibited. This dual mechanism distinguishes 2002D from purely starch-based thermoplastic starch grades, which are more moisture-sensitive and less melt-stable, and from fully bio-based polyesters, which differ in sealing behavior and modulus.

How Does the 2002D Grade Achieve Industrial Compostability under EN 13432?

Compostability claims for Bio-polyolefins 2002D are evaluated under EN 13432:2000, which requires characterization, biodegradation, disintegration, and ecotoxicity testing. Ultimate biodegradation is measured by ISO 14855-1:2012 under controlled composting conditions at 58 ± 2 °C. A passing grade must reach at least 90% carbon conversion to CO₂ within 180 days. Disintegration is assessed by ISO 16929:2019, with a criterion of 90% of the material passing a 2 mm sieve after 12 weeks. Ecotoxicity screening follows OECD 208:2006 and DIN EN 13432 Annex E, using plant emergence and growth tests on compost residues. Heavy metal limits are set by EN 13432:2000 Table A.1.

The starch-rich domains in 2002D are hydrolytically and enzymatically attacked by compost microbiota. The polyolefin fraction undergoes abiotic oxidation followed by mineralization. This mechanism is slower than bulk hydrolysis of PLA and more dependent on surface area and film thickness. Certification bodies such as DIN CERTCO and TÜV Austria require batch-specific evidence of compliance before OK compost industrial or seedling mark use is permitted. Labeling claims must reference the exact certification number and the compostability standard because home compost conditions do not reliably meet the temperature and moisture requirements of EN 13432:2000.

Rheological characterization of the 2002D grade is performed according to ISO 1133-1:2022 at 190 °C with a 2.16 kg load. Melt volume-flow rates for starch-modified polyolefin extrusion grades commonly occupy a 2–8 cm³/10 min band; for this grade, the supplier’s certificate should be consulted because starch content and residual moisture shift values. Density determined by ISO 1183-1:2019 typically falls between 1.05 g/cm³ and 1.25 g/cm³. Tensile properties measured on 1 mm compression-molded sheets under ISO 527-3:2018 show machine-direction tensile strengths in the 12–25 MPa range and elongation at break of 150–400%. Moisture content before processing is controlled below 0.1% by Karl Fischer titration under ISO 15512:2019. Biobased carbon content measured by ASTM D6866-22 Method B typically falls between 30% and 60%, depending on the starch loading and whether the polyolefin matrix contains renewable feedstocks.

Published data for this specific 2002D configuration is limited; the stated intervals are representative of starch-filled polyolefin extrusion grades characterized under similar protocols. For lot release, converters should request melt volume-flow rate, density, moisture, and tensile data from the supplier. Batch-to-batch variance is often dominated by starch source particle size distribution and moisture history. Granules stored in humid air above 60% relative humidity can pick up water and should be re-dried before processing. Granule geometry and bulk density are not specified in the standard datasheet but affect feeding consistency. Converters should verify bulk density under ISO 60:1977 and flowability on hopper loaders. For clear film, optical control includes haze measurement under ISO 14782:2021 and transmittance under ISO 13468-1:2019. A haze value below 10% on 40 µm film is typical for clear starch-polyolefin compounds when starch domains remain below 400 nm; values above 20% indicate poor dispersion or moisture-induced hydrolysis during processing.

Starch-Domain Clarity Retention Versus PLA and PBAT

Extrusion-grade starch composites differ from polylactic acid and polybutylene adipate terephthalate in matrix chemistry and failure behavior. PLA melts near 150–160 °C and provides high modulus but limited tear resistance and slow crystallization at film gauge below 30 µm. PBAT offers high elongation but lower modulus and higher blocking tendency. Bio-polyolefins 2002D combines a polyolefin matrix with dispersed starch domains; clarity depends on maintaining domain sizes below 400 nm and refractive index contrast below the visible wavelength limit. In blown film trials, haze development increases when starch particles exceed 1 µm, which can occur under low shear or with moisture above 0.2%.

Unlike PLA, the 2002D grade can be sealed on standard polyolefin sealing jaws without embrittlement at 120–140 °C. Unlike PBAT, it exhibits lower surface tack and better web release on cast chill rolls. However, the starch phase lowers water vapour barrier compared with neat polyolefins, and the grade is not a barrier polymer. It also retains a fossil-derived fraction, so it does not meet all renewable carbon targets that fully bio-based polyesters may satisfy. Certification for food contact is not automatic; compliance with FDA 21 CFR 176.170 or EC 10/2011 must be confirmed for each formulation and food type. The grade is not classified as an oxo-degradable material under EU Directive 2019/904. Unlike oxo-degradable polyolefins that fragment into microplastics, 2002D is designed for industrial composting.

Thermal degradation pathways in starch-modified polyolefin melts

Starch begins to undergo thermal decomposition above 180 °C with glycosidic bond scission, dehydration, and caramelization. In the 2002D grade, melt temperatures above 190 °C generate reducing sugars and organic acids that accelerate polyolefin chain scission. Thermogravimetric analysis under ISO 11358-1:2022 typically shows a two-stage mass loss: starch decomposition between 280 °C and 350 °C, and polyolefin decomposition above 400 °C. The practical processing limit is lower than the onset of rapid mass loss because viscosity reduction and colour formation precede char formation.

Barrel residence time is a controlling variable. At 180 °C, residence times below 3 min are recommended to limit starch degradation. Screw configurations with low-shear mixing elements reduce viscous heating and prevent localized temperature spikes. Filter packs should be sized to avoid pressure-induced overheating; melt screens upstream of the die should be 100 mesh or coarser to prevent gel accumulation.

When the 2002D Grade Replaces LDPE in Transparent Packaging Lines

Direct replacement of low-density polyethylene in transparent packaging extrusion requires adjustment of barrel temperatures, screw speed, and die gap because the starch-filled polyolefin exhibits lower melt strength and a narrower thermal degradation window. On single-screw extruders with grooved feed sections and 30:1 L/D, a barrel temperature profile from 150 °C at the feed zone to 180 °C at the metering zone is used. Die temperature is maintained at 160–180 °C, and melt temperature is held below 190 °C to avoid starch caramelization and volatile generation.

Pre-drying in a desiccant dryer at 70 °C for 4 h reduces moisture to below 0.1%. For blown film, die gap settings of 1.2–2.0 mm and blow-up ratios between 2.5:1 and 3.5:1 are employed. Cast film lines running monolayer structures at 30–40 µm thickness use chill roll temperatures of 20–40 °C to control clarity and web flatness. Production-scale twin-screw compounding with 36:1 L/D has shown that starch aggregation increases screen changer pressure when pre-drying is omitted or when moisture exceeds 0.2%. Shutdown procedures should include purging with a low-melt-index polyolefin to prevent starch residue from charring in the die.

The lower melt strength of starch-filled polyolefins compared with LDPE at equivalent melt index restricts maximum line speed and bubble stability. Use of an internal bubble cooling system or a low stalk height is required on high-output blown film lines. Draw resonance in cast film can be controlled by maintaining the melt temperature at the upper end of the recommended window and by increasing die lip opening. However, raising melt temperature above 190 °C accelerates starch thermal degradation, liberates volatile compounds, and produces gel-like defects. This narrow temperature window is the primary processing conflict for converters accustomed to LDPE.

Typical use cases include clear compostable produce bags, carrier bags, and secondary packaging films where industrial compostability is required by local regulation. The grade is evaluated on monolayer structures at 30–40 µm gauge. Multilayer constructions may be possible with tie resins and barrier layers, but compostability of the final structure must be reassessed under EN 13432:2000 because individual component certifications do not automatically transfer.

Operational boundaries for the 2002D grade include storage in sealed containers at relative humidity below 60% and avoidance of amine-based additive packages that accelerate starch discoloration. Pro-oxidant systems containing transition metal stearates should not be added above 0.5 wt% because they can initiate uncontrolled oxidative chain scission and reduce shelf life. The grade is not suitable for multilayer structures requiring high oxygen barrier unless paired with a barrier layer such as EVOH, and published data for this specific configuration is limited for retort or hot-fill applications.

Film converters evaluating seal integrity should apply ISO 527-3:2018 tensile characterization and ISO 6383-2 tear propagation resistance on cast film samples, with lot-to-lot variation monitored for melt flow and moisture content before startup. Extrusion equipment should be purged before shutdown, and regrind ratios above 20% are not recommended unless drying is verified, because reprocessing shifts melt flow and increases yellowing.