Ensuring Safety and Sustainability: The Regulation of Carbon Black Masterbatches for Food Contact Materials

Introduction

Carbon black masterbatches play a pivotal role in the manufacturing of food contact materials (FCMs), offering essential properties such as colour, UV protection, and thermal stability. However, their use necessitates stringent regulation to ensure consumer safety and environmental sustainability. In the European Union (EU), United States (USA), China, Japan, and South America specific regulatory frameworks exist that govern the production, testing, and approval of these materials, ensuring they meet strict health and environmental standards. This paper provides an overview of these regulations, the testing protocols for compliance, the purity requirements, and the environmental advantages of carbon black masterbatches compared to conventional packaging materials.

A Brief History of Carbon Black in Food Contact Applications

Carbon black has been historically used in a variety of applications, including inks, dyes, and as a pigment in packaging materials. Its stability, opacity, and resistance to chemical and UV degradation have made it a valuable component in food contact materials for decades. Early uses often lacked regulatory oversight, but as scientific understanding of health risks evolved, stringent regulations were introduced to ensure its safe application, particularly in FCMs.

Understanding Polyaromatic Hydrocarbons (PAHs) and Purity Requirements

Polyaromatic hydrocarbons (PAHs) are organic compounds containing multiple aromatic rings. These compounds can arise as impurities during the production of carbon black, posing potential health risks due to their carcinogenic and mutagenic properties. Regulatory bodies in both the EU and USA impose strict limits on PAH content to mitigate these risks, which are replicated in other countries.

Carbon black used in food contact applications must consist of nearly pure elemental carbon, ensuring minimal levels of impurities. The EU Plastics Regulation (EU No. 10/2011) mandates that the total content of the most potent PAH in carbon black (Benzo(a)pyrene) must not exceed 250ppb. With a restriction of 2.5% carbon black in the final article, to again limit potential exposure.

Similarly, in the USA, the FDA’s 21 CFR §178.3297 enforces the use of only two types of carbon black. Firstly, high purity furnace black type carbons with a Benzo(a)pyrene content of 5ppb and a total PAH level not exceeding 0.5ppm. Again, with a restriction of 2.5% carbon black in the final article. The second clearance for carbon black in Section 178.3297 permits the use of carbon black by the channel process in all polymers intended for contact with food. Historically, carbon black manufactured by the channel process has been understood to be relatively free of harmful impurities compared with the potential level of impurities, such as PAHs, which might be introduced when the black is manufactured by alternatively, particularly by the furnace process.

Regulations Governing Carbon Black Masterbatches

European Union

1. Framework Regulation (EC) No. 1935/2004:

Ensures that materials and articles in contact with food do not transfer harmful substances that could endanger health or alter food’s composition or taste.

2. Plastics Regulation (EU No. 10/2011):

Lists authorized substances for use in FCMs and sets specific migration limits (SMLs) for individual substances.

Requires overall migration testing to ensure total migration does not exceed 10 mg/dm².

3. Good Manufacturing Practices (GMP) Regulation (EC No. 2023/2006):

Enforces controlled manufacturing processes to maintain consistency and safety.

4. REACH (Registration, Evaluation, Authorisation, and Restriction of Chemicals):

Aims to improve the protection of human health and the environment by ensuring proper risk management of chemicals, including carbon black and PAH’s.

5. Additional Standards:

Products can be certified under standards such as OEKO-TEX (for textile-related applications), GS (Geprüfte Sicherheit for tested safety), and GADSL (Global Automotive Declarable Substance List).

6. Switzerland’s Ordinance on Materials and Articles:

Includes specific provisions for substances used in FCMs, complementing EU regulations.

Mercosur Standards

1. Mercosur Resolution No. 15/10:

Governs the use of colorants in FCMs within South America, specifying approved substances and migration limits – very similar to the EU10/2011 for carbon black restrictions.

2. Resolution No. 32/07:

Details additional safety and quality requirements for materials intended to contact food, ensuring harmonization across member states.

United States

1. FDA’s Food Contact Substance Regulations (21 CFR):

Defines indirect food additives and their permissible uses.

Requires Food Contact Notifications (FCNs) for new substances.

2. 21 CFR §178.3297:

Specifically addresses carbon black for food contact, imposing strict limits on PAH content and other impurities.

3. Testing and Approvals:

Comprehensive migration testing simulates real-world conditions to ensure safety during use.

Japan

Each product must be specifically approved by the Japan Hygienic Olefin and Styrene Plastics. Japan has adopted the same purity criteria, for carbon black, as EU 10/2011.

China

In China the National Food Safety Standard GB 9685-2016 implemented limits for use of additives in food contact materials and articles. Carbon blacks must have a benzo[a]pyrene content of less than 0.25ppm, mirroring EU 10/2011. In the final food contact article, a maximum addition level of carbon black is given, dependant on the polymer type.

Testing Protocols

To ensure compliance with regulatory standards, rigorous testing is conducted:

1. Chemical Analysis:

Identifies PAH levels, heavy metals, and other impurities using advanced techniques like gas chromatography-mass spectrometry (GC-MS).

2. Migration Testing:

Evaluates the release of substances into food simulants under specified temperature and duration conditions.

3. Toxicological Assessments:

Includes studies on potential carcinogenic, mutagenic, or reproductive effects of substances.

4. Ecotoxicology Assessments:

 Includes studies on potential disruption to aquatic organism and ecosystems.

Ecotoxicology

Carbon black is inorganic and insoluble in water; therefore, it has a low bioavailability potential in organisms. Acute testing to OECD test guidelines showed no negative effects on fish, daphnia or algae at 1,000 mg/l concentrations.

The German commission for the evaluation of water polluting substances has classified carbon black as a “not water endangering” substance (KBwS-No: 1742).

Carbon black and its manufacturing process does not include any ozone depleting substances (Montreal Convention – Ozone Depleting Substances).

Recyclability and End-of-Life Safety

Carbon black-containing plastics are highly recyclable, fitting seamlessly into established recycling streams for polymers like PET, PP, and PE. Unlike paper, which often requires extensive bleaching and chemical treatment, or glass, which is energy-intensive to produce and recycle, carbon black masterbatches offer a sustainable alternative. They comply with environmental directives such as:

RoHS (Restriction of Hazardous Substances Directive): Limits harmful substances like lead and mercury.

End-of-Life Vehicle Directive (ELV): Ensures safe disposal and recycling of materials.

Environmental Safety and Sustainability

Carbon black masterbatches offer significant environmental benefits compared to conventional packaging materials such as paper and glass.

Carbon Footprint Comparison

1. Paper:

Production involves significant water usage, chemical bleaching, and deforestation, contributing to environmental degradation.

While biodegradable, paper’s carbon footprint can exceed that of plastics when considering the entire lifecycle.

2. Glass:

Requires high-temperature processes for production and recycling, consuming large amounts of energy.

Heavier weight increases transportation emissions compared to lightweight plastic packaging.

3. Plastics with Carbon Black Masterbatches:

Low PAH levels and strict regulatory compliance make them environmentally safe.

Lightweight, durable, and energy-efficient to produce and recycle, reducing overall carbon emissions.

Conclusion

The regulation of carbon black masterbatches for food contact materials in the EU, USA, and other regions ensures consumer health and safety through stringent standards, rigorous testing, and compliance measures. These materials, when manufactured to meet purity requirements, are not only safe for food contact but also environmentally friendly. Their recyclability, lower carbon footprint, and reduced resource consumption make them a superior choice compared to conventional materials like paper and glass. Adopting such advanced solutions aligns with global sustainability goals, ensuring a safer and greener future for packaging technologies.

Authors: Dr Derek Hepburn and Catherine Penketh