In consideration of environmental protection, the “plastic restriction orders” of all provinces across the country have been continuously upgraded, and plastic packaging has been forcibly reduced and banned. As a substitute for plastic, paper products are facing a new wave of opportunities and challenges.
At present, greaseproof paper most of the plastic packaging can be replaced by paper packaging. The remaining part is temporarily unable to replace the paper due to the shortcomings of non-waterproof, non-oil-proof, and high-temperature resistance. Regarding waterproof and high temperature resistance, R&D personnel are constantly striving to find more suitable paper grades. For the shortcoming of non-oil-proof, various oil-proof wrapping papers have emerged on the market, but their safety is worrying. . These greaseproof papers may contain toxic substances, and long-term use will cause harm to the human body. For example, many food packages of fast food restaurants such as McDonald’s and Burger King have been detected with the carcinogenic substance PFAS, which has caused consumers to worry about the safety of food packaging. In fact, as early as 19 years, the well-known international journal “Environmental Health Perspectives” pointed out that oil-proof food packaging may be the source of PFOA (perfluorooctanoate) and PFOS (perfluorooctane sulfonate) in human blood. These substances can cause human diseases and Weight gain and affect fertility, child development and immune system.
So what is greaseproof paper?
It can be said that the performance of oil and water resistance has been regarded as a key indicator of the special performance of paper from the beginning. The hamburger paper, release paper, paper bag, paper box, paper plate, etc. used around us, as long as there is a grease barrier The paper needs to be processed in two ways: mechanical process transformation of pulp performance (professional point is called beating and refining, which is to increase the interweaving of pulp fibers), and adding oil repellent. The beating is too professional to explain, and it has nothing to do with the non-fluorine content, so I will focus on the oil repellent.
How did the oil repellent come from?
Here I have to introduce a plant — Tung tree. Tung oil produces oil. The oil content of its seeds is as high as 70%. The extracted tung oil is an important industrial oil. Paints and coatings are manufactured with extremely high economic value. Tung oil and wood oil are golden or brown in color. They are both excellent dry oils. They are shiny and inedible. They are impervious to water, airtight, non-conductive, resistant to acid and alkali, corrosion, and cold and heat. It is widely used in the manufacturing of paint, plastics, electrical appliances, artificial rubber, artificial leather, artificial gasoline, ink, etc. Since tung oil has so many functions, it is naturally also used for paper. Paper impregnated with tung oil can be made into oiled paper, as well as paper umbrellas, etc., which have good oil and water resistance.
The oil repellent that is truly made of artificial compounds starts from the 1950s. The United States DuPont company has researched and developed polytetrafluoroethylene emulsion and found that it has excellent water-repellent, oil-repellent and anti-fouling functions. In 1956, Petery Sherman and Sam Smith of the United States 3M company developed Scotchgard Protector (Scotchgard Protector), first put the fluorine-containing copolymer as a water and oil repellent product on the market, but the price was very expensive and the durability was poor. After the 1970s, Japan’s Asahi Glass and Daikin Co., Ltd. successively further modified fluoropolymers to obtain new fluorine-containing additives with multiple functions such as water and oil repellent, anti-fouling and anti-static. In the mid-1980s, similar products from the US 3M Company entered the Chinese market. After entering the 21st century, with corporate mergers and business transfers, the original market has undergone great changes. However, the domestic paper oil repellent is mainly produced by Daikin, which has been improved from carbon 8 to carbon 6 oil repellent. , Daikin’s oil-repellent products have gone deep into many levels, from the pulp to the surface sizing, and even some coated paper coatings. The oil-repellent, as the most effective additive, becomes the most effective additive for grease-proof paper. Indispensable “good helper”.
By using organic fluorides to treat paper and cardboard packaging materials (addition in pulp or surface coating and sizing), the paper is oil-repellent, so that the oil and grease in the food will not penetrate the paper. Perfluoroalkyl phosphate and perfluoroalkyl ammonium salt are the most common oil repellents.