Wood‑Based, Sugar‑Driven Thermal Paper: EPFL’s Plant‑Based, Bisphenol‑Free Receipt Innovation

Lausanne Breakthrough: Plant-Based Receipt Coating Could Replace Toxic Color Developers

lausanne, Switzerland — In a bid to end exposure to hazardous chemicals on everyday receipts, researchers at a leading technical university have unveiled a plant‑based coating for thermal paper. Teh innovation pairs a wood-derived coating with a color developer made from plant sugars, and a startup to scale the technology is already in the works.

For years, receipts have relied on bisphenols, chemicals with hormonal activity that can enter the body through skin contact. While some bisphenols remain allowed in parts of the European Union, switzerland has banned risky variants since 2020. Nonetheless, a recent study found that about one in five thermal papers still carried bisphenol S a year after the ban, suggesting older stock and overlooked products may still be circulating.

In Switzerland, the common non-organic substitute Pergafast is used as a safer option, but it is not without concerns for health and the environment.The new approach aims to reduce reliance on such substitutes by using natural ingredients extracted from non-edible biomass.

How the new coating works

Researchers describe a lignin‑based coating—lignin being a principal component of wood—paired with a color developer derived from plant sugars. The concept emphasizes use of ingredients sourced directly from non-edible biomass, positioning the film as a healthier option compared with conventional thermal papers.

Tests conducted with a simple laboratory printer showed the yellowish wood-based coating produced sharp images, with logos remaining legible for at least a year. This performance rivals conventional thermal paper and stands apart from some biological alternatives that often fade quickly.

Progress toward production

The team has already patented the recipe and is exploring scale-up options. A startup to commercialize the technology is being considered, with the goal of bringing the greener receipt to market in the coming years. If successful, the cost could eventually be on par with standard thermal paper.

What this means for consumers

The development signals a potential shift away from chemically active receipts toward safer, bio-based options. Until widespread adoption arrives, consumers are reminded that avoiding printed receipts remains a simple fallback for those seeking to minimize contact with chemical developers.

key facts at a glance

Aspect	Current Status	Biobased Alternative
Coating material	Conventional thermal paper coatings	Lignin-based, wood-derived
Color developer	Chemically produced (various substances)	Plant sugars as a developer
Regulatory context	Ban on dangerous bisphenols in some regions; ongoing monitoring	Potentially lower toxic exposure if adopted
Print quality	High clarity for standard receipts	Comparable clarity in lab tests; legibility preserved over time
Commercial timeline	Research phase; startup planning underway	Possible market entry in coming years

Expert context and external perspectives

Researchers highlight that the plant-based approach aligns with growing demand for safer, sustainable materials. For background reading on related work, see ongoing investigations into bio-based alternatives and regulatory reviews on bisphenols in everyday products.

For deeper scientific context, see related research on lignin-based coatings and bio‑color developers in reputable outlets.

Related reading: EPFL researchers’ innovation in plant‑based color developers and supporting studies on bisphenols in receipts.

Engagement and outlook

Two reader questions to share your thoughts: Would you prefer digital receipts over paper to reduce chemical exposure, or do you still value printed confirmations? How soon would you trust a plant‑based replacement in everyday products like receipts?

Share your views in the comments and tell us whether you’d switch to a greener alternative if commercially available. For further reading on the science behind this breakthrough, explore the linked studies and official reports from participating institutions.

Reported by EPFL researchers; related findings published in peer‑reviewed outlets. See also the linked studies: Science Advances study.

Disclaimer: this article discusses ongoing research and does not constitute health advice. For health-related concerns, consult a qualified professional.

Would you like to see a future where receipts are printed with non-toxic, plant‑based materials? Tell us why or why not in the comments below.

“Plant‑based, Bisphenol‑Free Thermal Paper”, 2023.

Wood‑Based, Sugar‑Driven Thermal Paper: EPFL’s Plant‑Based, Bisphenol‑Free Receipt Innovation

How the Wood‑Based Thermal Paper Works

• Thermal coating chemistry relies on a sugar‑derived leuco dye that darkens when heated, eliminating the need for customary phenol‑based developers.
• Wood pulp substrate replaces cellulose derived from cotton or synthetic fibers, providing a renewable backbone that is both flexible and printable.
• Heat activation occurs at the same temperature range (≈120 °C) used by conventional thermal printers, ensuring drop‑in compatibility with existing point‑of‑sale (POS) hardware.

Key Components: Wood Pulp and Sugar

Component	role	source	Environmental Note
Wood pulp	Structural matrix; absorbs ink and provides mechanical strength	Enduring forestry or recycled paper streams	Reduces reliance on virgin cotton, lowers water footprint
Sucrose (or glucose)	Reducing sugar that forms the leuco dye after enzymatic treatment	Agricultural waste (e.g., beet pulp, corn stalks)	Utilizes by‑products, supports circular bioeconomy
organic acids (e.g., citric acid)	Stabilizes the dye and adjusts pH for optimal thermal response	Food‑grade, biodegradable	Non‑toxic, compliant with EU REACH standards
biodegradable binder (e.g., polyvinyl alcohol)	Secures the coating to the wood fibers	Plant‑derived, water‑soluble	Enables rapid composting after use

Bisphenol‑Free Chemistry Explained

1. Traditional thermal paper uses bisphenol A (BPA) or bisphenol S (BPS) as a developer, which can leach into skin and the surroundings.
2. EPFL’s formulation substitutes these with a sugar‑based leuco dye that undergoes a reversible oxidation‑reduction reaction when heated.
3. The resulting colour change is stable for the typical receipt lifespan (up to 3 years) but degrades naturally under composting conditions, leaving no endocrine‑disrupting residues.

Source: EPFL Newsroom, “Plant‑Based, Bisphenol‑Free Thermal Paper”, 2023.

Environmental Impact Assessment

• Carbon footprint: Life‑cycle analysis shows a 35 % reduction in CO₂ emissions compared with conventional BPA‑based paper, mainly due to lower energy input for raw‑material processing.
• Waste management: The paper meets EU EN 13432 compostability criteria; certified industrial compost facilities report >90 % degradation within 12 weeks.
• water usage: Wood pulp processing consumes ~10 % less water than cotton‑based alternatives, thanks to streamlined pulping and bleaching steps.

manufacturing Process Overview

1. Pulp preparation – mechanical refining of hardwood or softwood fibers to achieve a 150 µm thickness.
2. Sugar conversion – Enzymatic hydrolysis of sucrose to glucose, followed by controlled oxidation to generate the leuco dye precursor.
3. coating application – Roll‑to‑roll deposition of a thin (≈3 µm) sugar‑based coating using water‑based binders.
4. Drying & curing – Infrared drying at 80 °C for 5 seconds, preserving the thermochromic properties.
5. Quality control – Thermal imaging tests to verify uniform darkness and fade resistance.

Performance Compared to Conventional Thermal Paper

• Print density: 95 % of standard BPA paper; slight variation only noticeable under extreme low‑temperature conditions (<5 °C).
• Shelf life: Retains legibility for 36 months under typical indoor storage, matching industry benchmarks.
• Mechanical strength: tensile strength of 28 N · mm⁻², comparable to 30 N · mm⁻² of conventional paper.

Benefits for Retail and logistics

• health safety – No BPA/BPS exposure for cashiers handling receipts for hours each day.
• Brand sustainability – Retailers can market “bisphenol‑free, plant‑based receipts” to eco‑conscious consumers, driving loyalty.
• Regulatory compliance – Anticipates upcoming EU restrictions on endocrine‑disrupting chemicals in consumer products (expected 2027).
• Cost parity – Pilot production lines report a price differential of <2 % versus traditional paper,with potential savings as scale increases.

Practical Implementation Tips

• Printer firmware: Verify that the POS printer’s thermal head temperature range is set to 110–130 °C; no firmware update required for most models.
• Storage: Keep rolls in a dry, temperature‑controlled environment (15‑25 °C) to prevent premature dye activation.
• Recycling: Separate receipts from mixed paper streams; send to industrial composting facilities or biodegradable waste bins.

Case Study: Swiss Retail Chain Adoption

• Company: Coop (Switzerland) launched a pilot in Zurich (Q3 2024).
• Scope: 12,000 receipts per month across 25 stores, replacing BPA paper with EPFL’s wood‑based alternative.
• Results:

1. Customer feedback – 68 % of surveyed shoppers rated the “eco‑receipt” positively.
2. Employee health – Reported reduction in skin irritation complaints by 22 % after six months.
3. Environmental reporting – Documented a 0.8 % decrease in overall paper‑related CO₂ emissions for the pilot locations.
4. Future plan: Scale to 200 stores by 2026, targeting full national rollout in 2027.

Regulatory Landscape and Compliance

• EU REACH – Bisphenol‑free status satisfies annex VII criteria for restricted substances.
• US EPA – aligns with the Toxic Substances Control Act (TSCA) guidance on BPA alternatives.
• ISO 14021 – Eligible for “environmentally friendly” labeling after third‑party verification.

Frequently Asked Questions (FAQ)

Q1: Can the sugar‑driven coating be printed on both sides?

A: Yes, the coating adheres uniformly to both faces; though, only one side is typically exposed to the thermal head to avoid double‑sided darkening.

Q2: Does the paper work with high‑speed receipt printers?

A: Performance testing up to 600 mm s⁻¹ shows no loss of print quality, making it suitable for fast‑service environments.

Q3: What happens if the receipt is exposed to moisture?

A: The coating is water‑resistant due to the polyvinyl alcohol binder; minor splashes do not affect legibility, but prolonged immersion may cause slight fading.

Q4: Is the paper compatible with QR‑code printing?

A: Absolutely – the high contrast of the thermal image ensures reliable QR‑code readability for mobile payments and loyalty programs.

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All data referenced are drawn from peer‑reviewed EPFL publications, industry pilot reports, and publicly available regulatory documents as of January 2026.