Packaging / Advertising & Office

New trends in international trade! Paper packaging, pulp molding, paper mulch and other products produced with fluorine-free waterproof and oil-proof agent are the first choice for export to Europe, the United States and Japan.

With the rapid development of the economy and the enhancement of environmental protection awareness, China's ban and restriction of plastic products will be fully implemented in January 2021, and the European Commission's guidelines on disposable plastic products, the packaging and packaging waste directive to be revised will be more inclined to paper packaging of plant fiber base materials, including pulp molded products packaging, and paper packaging will become the largest packaging material used in catering, food packaging and other fields.

1. The disadvantages of PE coated paper and silicone oil paper

Due to the contact with food containing oil, fat and water, paper packaging must be waterproof, oil-proof and impermeable. In order to obtain the effect of water and oil prevention, most of the food packaging paper is PE coated paper, that is, a thin layer of polyethylene plastic is coated on the paper, and some water-based coating materials are polyacrylate, polyvinyl alcohol, carboxymethyl cellulose, etc., forming a continuous and dense organic polymer film, so that oil and water cannot pass through the protective layer, thus achieving the purpose of water and oil prevention. High-end products are also packaged with silicone oil paper, which has three layers of structure: the first layer of backing paper, the second layer of coating film and the third layer of silicone oil.

This kind of polymer film itself is not oil-resistant, and the grease can still be spread on the surface of the film. Some contain bisphenol a grease, which may release harmful substances when contacting with high-temperature food. Moreover, this kind of polymer material can not be degraded in nature or degraded very slowly, which is difficult to recycle, high recovery cost and environmental pollution.

2. Disadvantages of fluorine-containing waterproof and oil-proof agent

In addition to film coating, a small amount of waterproof and oil repellent is added to the paper making process or a layer of waterproof and oil repellent coating is coated on the paper surface to reduce the surface tension of the paper, which can endow the paper substrate with waterproof and oil repellent properties, and does not affect the recycling of paper products. Although the water and oil repellent effect is excellent, this kind of water and oil repellent agent usually uses long-chain perfluoroalkyl monomers with a carbon atom number of more than 6, usually C8-PFCs with 8 carbon atoms (including 8 carbon perfluorocarbons). The longer the chain of carbon atoms in perfluoroalkyl, the better the water and oil repellent performance it has. This is because the fluoropolymer can form a film on the paper fiber, The fluorine-containing long side chains in the film can be extended and aligned on the interface. The film can significantly reduce the surface energy of the substrate, which is smaller than the general liquid, so it has the performance of water and oil resistance.

However, in recent years, studies have found that these long-chain fluoroalkyl compounds will produce perfluorooctanoic acid ammonium/perfluorooctane sulfonate (PFOA/S) which is harmful to the environment and human body during use. Low doses of these substances are bioaccumulative, especially when they are in contact with food for a long time, which has a strong toxicity to human body, and may cause genetic, reproductive, developmental, liver and cardiovascular diseases of organisms.

Therefore, the use of PFOA/S has been restricted by the European Union, Canadian environmental protection organizations and the National Environmental Protection Agency of the United States, and long-chain fluoroalkyl compounds (with carbon atoms greater than 6) have also been restricted to be used in waterproof and oil-proof agents for paper products, and C8-PFCs are gradually withdrawn from the market.

3. China's requirements for fluorine-containing additives

The new version of China's national standard GB 9685-2016 "Standard for the use of additives for food contact materials and products", compared with the old version of the national standard GB 9685-2008, deleted two kinds of perfluorinated compounds, namely diethanolamine mono-phosphate (1H, 1H, 2H, 2H-perfluoroalkyl) phosphate and bis (1H, 1H, 2H, 2H-perfluoroalkyl) phosphate, perfluoroalkyl propionate copolymer (perfluoroalkyl acrylate copolymer).

At present, the toxicological data of C6-PFCs are still limited. Research shows that they are not as bioaccumulative and potentially systemic and developmental toxicity as C8 substances. Animal and epidemiological studies have shown that C6-PFCs will not accumulate in organisms because they can be rapidly excreted. Therefore, the use of short-chain C6-PFCs in food contact materials is still allowed in China.

According to the provisions of GB 9685-2016 Standard for the Use of Additives for Food Contact Materials and Products, GB 4806.6-2016 Plastic Resins for Food Contact, GB 4806.10-2016 Coatings and Coatings for Food Contact and other standards, some fluorine-containing small molecules or polymers can be used for food contact materials and products under certain restrictions. For example, the tetrafluoroethylene polymer or the copolymer of tetrafluoroethylene and other fluorine-containing monomers (hexafluoropropylene, perfluoropropyl vinyl ether, etc.) can be used for plastic products or coatings, but the migration limit of fluorine-containing compounds such as tetrafluoroethylene, hexafluoropropylene or perfluoropropyl vinyl ether shall be met (0.05 mg/kg, 0.01 mg/kg and 0.05 mg/kg respectively). Fluorine-containing compounds such as difluoromethane, 2,2-ethylidene bis (4,6-di-tert-butylphenyl) fluorophosphoronitrile, bis [ethyl (perfluorooctane) sulfonamide ethyl] ammonium phosphate can be used as additives in food contact with plastic or paper products.

4. Fluorine-free waterproof and oil-proof agent

In January 2015, the US FDA released a message that food contact substances (FCSs) containing monoethanolamine and diethanolamine, valeric anhydride, and perfluoroalkyl substituted phosphonic acid were prohibited from being used as waterproof and oil-proof agents for paper and paperboard to contact water and oil food. In January 2021, the US FDA announced that it would require manufacturers to voluntarily phase out the use of food contact packaging materials containing PFAS/PFOA within three years, which would be enforced from January 2024. By July 2022, 26 states in the United States had introduced legislation restricting the use of PFAS/PFOA, and 11 states had implemented it.

The restrictions on PFAS within the EU are gradually expanding. In Denmark, the ban on the use of paper and paperboard food contact materials containing perfluorinated and polyfluoroalkyl compounds has come into full force in July 2020. The Netherlands, Germany, Norway, Denmark and Sweden are proposing amendments to REACH regulations to comprehensively restrict the manufacture and use of PFAS/PFOA.

New trends in international trade! Fluorine-free waterproof and oil-proof agent has become a research hotspot in the industry. It is more safe and environmentally friendly. The paper packaging, pulp molding and paper mulch products produced by it are the first choice for international trade export to Europe, the United States and Japan. Although the same waterproof and oil-proof performance as fluorine-containing products can be achieved through surface treatment such as film coating and spray coating, its high equipment investment and treatment costs are doomed to be unable to be used on a large scale. The advantages of the fluorine-free waterproof and oil proofing agent added in the slurry are that it does not require equipment investment and the cost is controllable. The disadvantage is that the oil proofing performance does not reach the effect of fluorine-based products. However, the industry also has different views on the anti-oil effect test of fluorine-free additives. For example, the previous test standard for the impermeability of 95 ℃ hot oil for 30 minutes of pulp molded products was considered by the industry and the end consumer market to be far beyond the actual use scenario. At present, the European and American markets are more rational to accept the physical test results, or select the test standard of 30 minutes' impermeability of hot oil at a certain temperature (30 ℃, 40 ℃, 70 ℃) according to the end use scenario and customer needs. After all, the solution that can be widely accepted by the international trade market must be practical and cost-effective at the production end.