Environmental Protection: The Ultimate Attribute of the Development of Food Flexible Packaging

Introduction: Food packaging is the last process in the modern food industry. It plays an important role in packaging, protection, beautification, promotion and convenience of food storage, transportation and sales. To a certain extent, food packaging has become an integral part of food. component. At present, the situation facing the food packaging industry in China is not optimistic. Many food packaging materials on the market are difficult to meet the national requirements for food safety, hygiene and environmental protection. Aromatic solvents such as toluene are used in large quantities. According to statistics, the amount of chlorinated polypropylene ink used for BOPP film printing accounts for more than 60% of the plastic inks for food and pharmaceutical packaging produced by large-scale manufacturers in China in 2004, and the ink solvents and dilution solvents for the system The amount of benzene solvents generally accounts for about 50%, which not only endangers human health, but also affects the healthy development of China's food packaging industry and even the entire food industry.

First, the development status of food flexible packaging

China's current food packaging bags are mainly gravure printing. The various food packaging bags we see in supermarkets include biscuits, cakes, milk powder and other packaging, and basically use chlorinated polypropylene. The majority of ink printing. In Europe and the United States, most countries use flexo printing, flexo printing is slightly inferior to gravure printing, and the quality of printing is low, but it is an advantage in environmental protection. This is because the U.S. government has formulated tough environmental laws and regulations. In addition to good social education, consumers tend to use environmentally-friendly products. However, in China, the acceptance of environmental technologies such as flexo printing is not high in the market. Because flexo printing uses the principle of embossing, compared to the gravure of heavy oil, gravure has relatively less ink, is relatively thin, and the degree of coloration is not very high. In terms of brightness, it is not as good as gravure. The domestic soft packaging consumption has long been in a fixed position with high gravure coloration and high brightness. At the moment, it is still not able to accept the printing technology of this new environmental concept. Therefore, gravure printing will continue to maintain its absolute value in the printing of plastic flexible packaging. Leading position.

At present, China's plastic gravure ink, benzene solvent-based inks account for a large proportion, while developed countries such as Europe and the United States have clearly banned the use of benzene solvents in food packaging and printing, flexible packaging inks can only be alcohols, esters, Water as a solvent. Aromatic hydrocarbon solvents are suspected of being carcinogenic and therefore are not allowed to be used in printing inks for food packaging, toys, etc.; ketone solvents are also subject to great restrictions because of their large odors. In food packaging inks used in Europe and the United States and elsewhere, the solvent residue is specified as ethyl acetate and isopropyl alcohol in an amount not to exceed 5 mg/m2. The U.S. Food and Drug Administration clearly stipulates the types of adhesives and inks used for food or pharmaceutical packaging. Any chemical that is not mentioned in the regulations is strictly prohibited. Therefore, alcohol-soluble, ester-based, water-based and other environmentally friendly benzene-free ink in the plastic gravure printing will be increasingly concerned by the industry, and will soon dominate the food and pharmaceutical packaging ink printing market.

Second, the green of food flexible packaging can not be delayed

The toxicities of benzene solvents are relatively large. The US FDA lists carcinogenic chemicals. If the substance penetrates into the skin or blood vessels, it will endanger human blood cells and hematopoietic function with the blood, damage the nervous system of the human body, and cause leukemia; residues in the packaging The benzene solvent in the film is easily absorbed by the food in the package, resulting in food contamination. Although most of the toluene solvent can be removed by drying during the printing of the benzene-soluble ink, it is still easy to generate residue due to the strong adsorption of the pigment in the ink.

As early as 1995, the Japan Gravure Printing Industry Federation issued the "Promoting Benzene-free" Proposal. End-users proposed to control the residual content of food packaging solvents below 1mg/m2 and promulgated a ban on food packaging bags. The use of benzene-containing ink NL autonomous regulation. In China's current food packaging bag standard, the solvent residue is required to be 10 mg/m2, but there is no clear indication of which solvent type; the recommended standard requires toluene to be <3 mg/m2. Recently, CCTV's "Quality Report" broadcasted the "poisonous milk powder bag" incident in Lanzhou. As the toluene solvent residue exceeded the standard, the failure rate of sampling food packaging bags was as high as 50%, and the food safety problem was very serious, causing widespread public concern. To this end, the country will also issue relevant mandatory standards for food packaging materials next year. Benzene-containing inks will be severely restricted by the relevant national laws and regulations and will even be prohibited from being used in the packaging and printing of foods and pharmaceuticals.

Third, green food packaging technology reform

1, fundamentally eliminate

China's plastic color printing manufacturers vary in size, with small-scale color printing manufacturers accounting for the majority; production equipment performance levels are also uneven. Due to the increased competition in the food packaging industry, some small-scale manufacturers only pay attention to the product cost, neglect the inherent quality of the product, and lack the evaluation of comprehensive performance and safety and health. In view of this, printing companies have made great efforts to strictly control printing equipment, raw materials, and process parameters. However, toluene has a good affinity for polyolefin films such as BOPP. When printed on bags, especially on printed materials with large ink areas and thick ink layers, solvent residues are difficult to evaporate, although strict process management is required. Once out of control, there may be excess benzene solvent residues. Some large-scale printing manufacturers, despite possessing advanced equipment, often have difficulties in controlling the amount of toluene residue in printed matter, which has become a difficult point in the quality control of soft packaging. In order to fundamentally solve this problem, many manufacturers have adopted alcohol-soluble compound inks as a new printing and laying bottom process, and the amount of toluene residues has been greatly reduced, which can meet the current industry's recommended control standard of <3 mg/m2. However, even if it is still inconsistent with the EU and US standards, export products still cannot pass the technical barriers of developed countries such as Western Europe. If China introduces a mandatory standard next year that prohibits the use of benzene-based solvent inks in food and pharmaceutical packaging, then food and pharmaceutical packaging printing must use alcohol-soluble, ester-based, and water-based environmentally friendly inks in an all-round manner, so as to fundamentally solve the problem in China. The safety and health problems of food and drug solvent residues in the printing and packaging industry. This will also be a leap forward in the improvement of printing technology and quality in China's flexible packaging industry.

2, improve the ink connection material

In Europe and the United States, plastic ink can be divided into two major types of surface printing and inward printing. Considering the production cost and market development requirements, the current surface printing ink is mixed with alcohol-soluble polyamide and nitrocellulose as connecting materials, and the produced ink can completely replace the current surface printing ink using toluene and isopropyl alcohol as solvents. . The performance of surface printing ink with polyester and polyurethane as the main connecting material is very good. At present, it is the leading ink for high-grade flexible packaging printing in Europe and the United States. Some of the higher requirements for printing and packaging use this type of ink. Water-based plastic film flexible packaging inks have been reported abroad in recent years in the application of flexographic printing. At present, domestic use of benzene-free (or alcohol-soluble) composite ink, mainly polyester / polyurethane or PVB resin as the main binder, can print BOPP, PET, NY film, its printability, complex suitability, and specific functionality All requirements meet or exceed benzene inks. In addition, there have been substantial breakthroughs in the development of acrylic polymers, the development of alcohol-soluble inks that use PVB as a binder, and the use of water-based flexible packaging inks. Similar alcohol-soluble inks have been marketed in bulk, such as Zhejiang New Oriental Ink, Shanghai. DIC, Shanghai Si Kebai and Dalian Schmidt have produced alcohol ink products with their own characteristics.

Fourth, advocate "people-oriented" food packaging concept

Zhejiang New Oriental Ink Group advocates the "people-oriented" concept of food packaging. Over the years, it has cooperated with (H.K.) Singapore-based HG RESIN Corporation, combining the technical development characteristics of foreign alcohol-soluble inks, fully realizing the adjustment of industrialized organizations, and pioneering the introduction of food and pharmaceutical packaging. Use environmentally-friendly ink series: Among them, Gouda 421FD alcohol-soluble compound ink is used exclusively for the printing of BOPP and other films; Chaolifu 303FD alcohol-soluble compound ink is used for PET and ONY film printing; and Chaolifu 313FD and 304FD are used. Alcohol-soluble functional inks for LDPH co-extruded films and other products, these alcohol-soluble (no benzene, no butanone) environment-friendly ink has been used in large quantities in liquid food packaging such as milk and frozen foods, fresh vegetables, milk powder , biscuits, chocolate and other packaging. Among them, Howda 421FD white ink can also be used together with chlorinated polypropylene color ink to achieve a significant reduction in the amount of toluene residues in the printing film. This is the current process for the transition from benzene-based inks to alcohol-soluble inks used by domestic printing manufacturers. method. In the field of cooking packaging inks, the new generation (single-component) Chao Lifu 3100FD retort (no benzene, no butanone) alcohol-soluble composite ink has also been fully introduced to the market. Environmental ink compatibility and post processing flexibility are superior to benzene inks. It is an inevitable choice for foods and pharmaceutical flexible packaging inks. New Oriental Ink Group has been committed to the development of green products for years to improve the human health environment. , And hope that with the vast number of color printing manufacturers, equipment manufacturers, end users, etc. work together to jointly promote China's flexible packaging industry towards environmental protection, health and safety in the direction of development.


Chairman of Zhejiang New Oriental Group Co., Ltd. Fan Jiayu

Source: China Packaging 2005/6