Detailed explanation on the environmental protection issues of thermal paper in kids instant print camera

Instant printing cameras are an excellent way for children to explore photography, creativity, and instant satisfaction, and the printing process uses thermal paper without the need for ink. However, traditional thermal paper coatings contain bisphenol A (BPA) or bisphenol S (BPS) as color developing agents, but studies have shown that BPA and BPS are organic compounds commonly used in the synthesis of materials such as polycarbonate and epoxy resin. However, they may have adverse effects on human health, such as causing endocrine disorders and inducing cancer.
In this blog, we will explore the environmental issues of paper in children’s printing cameras, while emphasizing the dangers of BPA and BPS in instant thermal printing and how to find safer alternatives.

Regarding Bisphenol A (BPA) and Bisphenol S (BPS)

-Color development principle: It turns black by reacting with an acidic color developer through heating.
-How it affects the human body: Children touching printed photos may unknowingly transfer chemicals to their hands and then into their mouths. It may also be absorbed through the skin, leading to potential health risks.
-Limitations: A 2020 study in Environmental Science and Technology suggests that BPA/BPS may have endocrine disrupting properties (detection limit of 0.1 μ g/L), and the European Union’s ECHA is assessing its risk.

The core difference between BPA (Bisphenol A) in thermal paper and BPA Free (BPA Free) thermal paper lies in the composition of the color developer and its health risks. The following is a specific comparative analysis:
Core components and color development principle
-BPA thermal paper
Color developer: Bisphenol A (BPA) is used as the main color developer. BPA reacts with acidic developer to turn black when heated, achieving ink free printing137.
BPA exists in the form of free monomers in coatings and easily migrates to the skin.
-BPA Free Thermal Paper
Alternative colorants: Bisphenol S (BPS), Bisphenol F (BPF), or non phenolic substances such as vitamin C derivatives are commonly used Pergafast ® 201, etc.).
Technological upgrade: Some products use more environmentally friendly color systems (such as Dow Chemical’s “phenol free technology” which has won the Green Chemistry Award).

Protective measures during use

-Reduce direct contact: Children should wash their hands immediately after operation to avoid wet hands coming into contact with thermal paper;
-Control usage frequency: Limit the number of prints per session for children to avoid long-term cumulative exposure.
-Properly dispose of waste paper: Discard thermal paper separately and avoid mixing it with food or toys

Safe alternative solutions

-Phenol free polymers: such as BASF Pergafast ® 201 (patent number EP2385069), color developed through polymerization reaction, completely free of phenolic substances, migration amount<0.01mg/kg (detected by LFGB in Germany).
-Vitamin C derivatives: The Ascendic Acid Thermal Paper developed by Mitsubishi in Japan has a color development temperature of 90-120 ℃, a cost 15% -20% higher than traditional materials, but a biodegradation rate of 98% (JLTA certification).
-Organic acid metal salts: Zinc citrate/calcium stearate composite system, with slightly lower color sensitivity (requiring 0.6-0.8N pressure, ordinary thermal paper only requires 0.3N), but meets FDA 21 CFR 175.300 food contact standards.

Future Directions

1. Nanocellulose coating: The combination of nanocellulose and carbon powder developed by INNVENTIA laboratory in Sweden has a color resolution of 600dpi, and the cost is expected to be reduced to 0.28 yuan/㎡ by 2025.
2. Biobased color reagents: such as cashew phenols extracted from cashew shell liquid, NKK Company in Japan has achieved small-scale production (monthly production capacity of 200 tons).

It is recommended to prioritize products with FSC certification or Blue Angel logo. These thermal paper not only have no BPA, but also reduce the carbon footprint of the entire lifecycle by more than 40% (according to the 2022 assessment data from the World Wildlife Fund).

Summary: Risk is controllable but requires proactive intervention
Low frequency exposure has low risk: Short daily exposure (such as occasionally printing photos) generally does not cause acute harm, but long-term use in children should be cautious of cumulative effects.
Key populations require strict protection: pregnant women, infants, and developing children should avoid contact as much as possible.
The environmental protection shortcomings need to be addressed: the difficulty in degrading thermal paper and the lack of a recycling system require collaborative improvement in the industry chain.