GreenHub
Compostable Bioplastics: Materials, Standards and Industrial Applications
Two materials can both be sold as compostable bioplastics and still need different processing conditions, suit different products and qualify for different composting environments. For a manufacturer, the useful question is which formulation can meet the part’s requirements and reach an appropriate end-of-life route.
This guide explains the material families, the evidence behind compostability claims and the practical decisions involved in selecting a compound for industrial production.
What makes a bioplastic compostable?
Compostable plastics are designed to biodegrade and disintegrate under specified composting conditions, while meeting requirements on their constituents and their effects on compost. A compostability claim needs a defined environment and supporting evidence for the material or product concerned.
The word bioplastic covers a broader group. European Bioplastics uses it for plastics that are bio-based, biodegradable, or both. So a compostable plastic can contain fossil-derived components, and a bio-based plastic can be non-compostable. Bio-based polyethylene is one example of the second case. European Bioplastics explains these distinctions.
Bio-based describes origin. Compostable describes behavior under specified end-of-life conditions. Neither term, on its own, tells you how a material will perform on your line or what its carbon footprint will be.
For the wider classification, see our guide to bioplastics and plastic replacement materials.
The main material families
Compostable compounds can combine several polymers with additives, fillers or fibers. A polymer name helps identify a starting point; the finished formulation is what you qualify.
These categories can overlap: a fiber-containing biocomposite may use one of the polymer families listed below as its matrix. A compostable compound does not necessarily contain fibers.
The table below gives practical reasons to shortlist each family and the trade-offs to investigate. These are typical tendencies, not specifications for every grade. Blending, additives, fiber content and processing can change the result. Compostability must be verified for the proposed formulation and intended article.
| Material family | Why consider it? | Main limitations | Applications to evaluate |
|---|---|---|---|
| PLA-based materials | Stiffness and, in suitable grades, transparency for rigid products | Unmodified PLA can be brittle and has limited heat resistance; tougher or heat-resistant formulations need their own validation | Rigid packaging, thermoformed trays and injection-molded parts |
| PBS-based materials | Flexibility and ductility for applications where a brittle material would be unsuitable | Stiffness, heat resistance and melt behavior depend on the grade and blend; bio-based content depends on feedstock sourcing | Flexible packaging, coatings and selected molded parts |
| PHA-based materials | A bio-based polyester family spanning rigid and more flexible formulations | Some types are brittle and sensitive to processing temperature and residence time; properties cannot be generalized across the family | Selected rigid packaging, films and coatings, depending on the PHA type |
| PBAT-containing blends | Flexibility and extensibility, including as a blend component for more brittle polymers | Low stiffness limits its use alone for rigid parts; commonly fossil-derived, so compostability does not imply high bio-based content | Compostable bags, liners and flexible films |
| Starch-based blends | A renewable starch component that can be formulated into flexible or rigid compounds | Moisture sensitivity can affect storage, dimensions and performance; the other blend components strongly influence behavior | Bags, liners and selected molded products |
| Fiber-containing compostable biocomposites | Renewable or upcycled biomass incorporation, reduced polymer content and potential gains in targeted mechanical, dimensional or barrier properties. Potential carbon-footprint reduction requires comparative assessment | Fiber type, size, loading and treatment must suit the polymer and process. Flow, moisture response, flexibility and surface quality require validation, particularly for thin films and coatings | Molded parts, extruded products, sheets, films, bags and selected coatings, flexible & rigid packaging, films, using formulations developed for the required process and performance. |
These families sit within the wider bioplastic material landscape. A commercial compound may combine several of them to balance stiffness, flexibility and processing behavior. Buyers therefore need data for the complete compound, not just the names of its constituent polymers.
For technical background on these formulation differences, see the research reviews of PLA and PHA properties and thermoplastic starch and polyester blends.
Home or industrial composting: choose the route first
Industrial composting uses managed processing conditions. Home composting operates under different, more variable conditions. A material specified for one route should not be assumed to qualify for the other.
The practical question is where the finished product will actually go. A certified industrial-compostable item still needs collection and acceptance by an appropriate treatment operator. A home-compostable item needs suitable home-composting conditions and clear disposal instructions. Neither claim means that the product should go into residual household waste expecting to compost, or that it can be left outdoors.
The European Commission emphasizes that compostable plastics need appropriate waste management and that environmental benefits depend on the application and the wider system. European Commission policy framework
Our home-compostable versus industrial-compostable comparison explains the two routes in more detail. For projects that need a home-compostable route, our home-compostable compound range is a starting point for injection-molding and extrusion enquiries, including PLA-free options, reviewed against the intended application.
Read the standard and the certificate together
A standard defines requirements. A certification scheme assesses conformity within a stated scope. Buyers need both the reference and the document covering the material or product.
| Reference | What it addresses |
|---|---|
| EN 13432 | Industrial compostability of packaging, including biodegradation, disintegration, constituent limits and effects on compost |
| EN 14995 | Evaluation of compostability for plastics beyond the packaging-specific scope of EN 13432 |
| ASTM D6400 | Plastics intended for aerobic composting in municipal or industrial facilities |
| OK compost INDUSTRIAL | A TÜV AUSTRIA certification scheme for industrial compostability |
| OK compost HOME | A separate TÜV AUSTRIA certification scheme for home compostability |
| NF T 51-800 / AS 5810 | Standards addressing plastics suitable for home composting |
These references have different scopes and are not interchangeable. See the European Bioplastics overview of standards and labels.
Confirm the certification status early: certificate holder, exact grade or product, validity and any thickness, composition or use limitations. The evidence should be sufficient to verify the claim before relying on it for a purchasing decision. Detailed reports or confidential supporting documents can be shared under agreed confidentiality arrangements where appropriate.
A resin certificate is useful evidence, but it does not automatically certify a finished article made with additional colorants, coatings, labels or adhesives. Confirm with the supplier and certifier what remains covered and what requires further assessment.
Match the material to the industrial application
Start with the product’s service conditions and intended disposal route, then shortlist materials. Two parts made by the same process can have very different requirements.
| Application being evaluated | Main material-selection questions | Evidence needed before scale-up |
|---|---|---|
| Injection-molded rigid parts | Can the material fill the geometry and meet stiffness, impact, heat and dimensional requirements? | Grade data, molding trials and tests on representative parts |
| Extruded tubes, profiles or sheets | Can the formulation maintain the required shape and dimensions through processing and cooling? | Extrusion trials, process guidance and dimensional checks |
| Flexible bags and films | Does the grade meet flexibility, tear, sealing and storage requirements? | Film-specific data, conversion trials and the relevant end-of-life evidence |
| Coatings on paper or other substrates | Can the formulation form a continuous layer with the required adhesion, barrier performance and sealing behavior at the target thickness? | Trials using the intended coating process and substrate; testing of the complete coated article, including relevant compostability evidence |
| Food-contact packaging or components | Is the complete formulation suitable for the intended food, temperature and contact duration? | Applicable composition and migration evidence, supporting documentation and declarations |
| Horticultural products | Will the item be collected for composting, or is it intended to remain in soil? | Evidence for the actual environment; a compostability claim does not establish soil biodegradability |
These are application categories to assess, not a statement that every compostable grade serves every use. A film grade and an injection grade should not be treated as interchangeable because they share a polymer family. Selecting the base polymer is one step; the complete formulation must also suit the process, product thickness and performance targets.
Food contact requires its own assessment. In the EU, the framework Regulation (EC) No 1935/2004 applies, alongside relevant specific measures such as Regulation (EU) No 10/2011 for plastics and good manufacturing practice requirements. Compostability certification does not replace that assessment. European Commission food-contact legislation
For products sold in Europe, also check whether single-use-plastics restrictions apply to the product category. Compostability is not a general exemption from product restrictions.
Where biocomposites fit
Some compostable materials incorporate fibers from agricultural residues or other biomass. These are compostable biocomposites when the complete formulation meets the relevant compostability requirements.
The development starts with the application: select the polymer or blend, fiber type, loading and preparation around the required properties and production process. A rigid molded component, flexible bag and thin coating will call for different formulation choices.
Introducing biomass can reduce the polymer fraction and provide a use for agricultural residues. With appropriate fiber-polymer bonding, it can also improve selected properties such as stiffness, strength, dimensional stability or barrier performance. Each objective needs its own validation: a gain in stiffness does not establish a gain in impact resistance or flexibility. Visible fibers and texture are possible design outcomes, rather than defining features of every biocomposite.
Fiber preparation and interface design help control dispersion, bonding and moisture response. Finer particles alone do not guarantee easier processing: loading, particle shape, surface interactions and agglomeration also affect flow. Treatment can reduce moisture sensitivity, while the matrix and service conditions remain part of the assessment.
Applications extend to films, bags and selected coatings when the formulation and process are suitable. Research on treated-cellulose/PBAT blown films illustrates the possibilities of interface engineering. Thin products bring specific constraints, including fiber dimensions, dispersion, layer continuity, stretching and sealing. The appropriate fiber content may be much lower than in a rigid component, and some projects may call for a compound without fibers.
At Biomera, fibers undergo dedicated preparation before compounding. We design surface activation, functionalization and compatibilization around fiber chemistry × polymer matrix × processing window, drawing on proprietary interfacial-engineering know-how. The aim is to improve dispersion, interfacial bonding, thermal stability and final mechanical properties for the selected application.
Carbon reduction and compostability remain separate development objectives. Fibers can influence degradation behavior, but their presence does not establish faster composting or home compostability. Claims must correspond to evidence for the complete formulation and intended article.
Our technology page explains the development approach. The compostable-biocomposites guide focuses on this particular material route.
Assess carbon performance separately
Compostability addresses an end-of-life route. Carbon footprint assessment measures greenhouse gas emissions and removals within a defined study boundary. A project may target both, but each needs its own evidence.
Replacing part of a polymer with biomass reduces its share in the formulation; the reduction in fossil content depends on which polymer is replaced. A lower carbon footprint is a potential development benefit that needs comparative evidence. Include biomass sourcing, drying, milling, surface treatment, compounding, transport and conversion, alongside product mass, service life and end-of-life assumptions. The result must reflect equivalent product performance.
For a comparison between finished products, define the same function. Comparing one kilogram of each material may not represent two parts that differ in weight or useful life. ISO 14067 provides requirements and guidance for product carbon-footprint quantification; it does not establish every environmental benefit of a material.
From application brief to material trial
Material selection is a shared technical process. The customer defines the product and production constraints; the supplier assesses material options and available evidence. Both parties then agree what needs to be tested.
1. Describe the application and production requirements
A useful brief covers the following information, where known:
- Application and use conditions: what the product does, its geometry and wall thickness, expected service life, temperature, moisture exposure and food contact if relevant.
- Process and existing equipment: injection molding, extrusion or another process; the current resin; and whether existing machines, molds or dies must be retained. Identify what can be adjusted and what is fixed.
- Performance targets: stiffness, impact resistance, flexibility, heat resistance, appearance and dimensional tolerances. A current part or specification can provide a useful reference.
- Market and end-of-life requirements: where the product will be sold, the intended composting route and the documentation needed for the application.
- Commercial targets: expected annual demand, anticipated initial order, target material or finished-part cost and project timeline. Estimates are useful at an early stage.
You do not need a complete technical specification to start the conversation. Share what is available and identify the open questions. Detailed machine specifications, tooling drawings and processing settings can follow when needed, under appropriate confidentiality arrangements.
2. Assess the material options and supporting evidence
The supplier can then assess whether an existing grade is a candidate or whether custom formulation is needed. This review should identify the available data, likely processing adjustments and any performance or documentation gaps.
For an existing grade, the evaluation can draw on its technical data sheet, test methods and conditions, processing and storage guidance, and relevant certification information. For a custom formulation, initial data may be provisional; the final grade specification follows development and validation.
Agree which compostability and application-specific documents are relevant, what can be shared at the current stage and what further assessment is needed. Food-contact evidence, for example, must correspond to the intended use. An existing certificate and a certification still being pursued should be clearly distinguished.
3. Agree the trial scope and commercial terms
A trial plan can be a short written agreement defining the material to evaluate, the equipment to use, the checks to perform and what counts as an acceptable result. It should identify who runs the trial, who tests the parts and who reviews the findings.
Trial quantity means the amount of material needed for the agreed evaluation. Laboratory screening, injection-molding trials and extrusion runs can require different quantities. The amount should be agreed around the equipment, setup needs and number of representative parts required; it is separate from a production minimum order.
Before proceeding, agree the timing, documentation, support and applicable charges for material, shipping, development or testing. Trial material and technical services are subject to the agreed quotation; a request for evaluation does not imply that they are free. Production minimum orders and indicative lead times can be discussed against the expected demand.
For help evaluating the supplier’s role, see our manufacturer, compounder and material-supplier guide.
Explore the Biomera materials range to compare the available approaches.
Frequently Asked Questions
Are all bioplastics compostable?
No. Bioplastics include bio-based materials that are not compostable. Check the end-of-life evidence for the specific grade and finished product.
Are compostable plastics always plant-based?
No. Compostable formulations can contain fossil-derived polymers. Bio-based content and compostability describe different characteristics and need separate evidence.
Does PLA-free mean home compostable?
No. PLA-free describes the absence of one polymer. Home compostability must be supported for the complete formulation and the relevant product conditions.
Can compostable compounds run on existing plastic-processing equipment?
Suitable grades can be processed by injection molding or extrusion on standard equipment. Share the current resin, the process and any need to keep existing machines, molds or dies. Compatibility still needs review and trials, including which settings can change and whether equipment or tooling changes would be needed.
Can a compostable product also be reusable?
The two objectives can be considered in the same project. Reuse needs evidence for the intended service life, cleaning and use conditions; compostability needs separate end-of-life evidence. Neither establishes the other.
Can fiber-containing compostable compounds be used for bags or coatings?
Yes, with formulations developed for the intended process and product. Fiber dimensions, loading, dispersion and surface treatment must suit the required thickness, flexibility, barrier and sealing properties. Some applications need low fiber loadings or a compound without fibers. Suitability is established through formulation data and trials on the intended equipment.
Which compostable bioplastic is best for my product?
The right choice depends on the part, process, performance targets, market and disposal route. Start with those requirements, then compare documented grades and validate the shortlisted material on representative parts.
