Greening of Printing Inks for Food Packaging

The hidden dangers of food packaging ink

The competition of food packaging and printing products is not only the competition of the quality of the product itself, but packaging safety has also become a key issue affecting the quality of the product. How to improve the quality and safety of food and food packaging and protect the health of consumers has become a focus of increasing attention from the government and consumers.

According to the survey, nearly 670 cities across the country have various types of printing machines, and the inks used are mainly divided into organic solvent-based inks, water-soluble inks, high-solid inks and benzene-free inks. Organic solvent-based inks use low-boiling volatile organic compounds such as toluene, xylene, acetone, butanol, and ethyl acetate as solvents, which are widely used because of their fast printing speed, good print quality and low cost.

In the process of use, due to the volatilization of organic solvents, a large amount of toxic and harmful organic waste gas will be generated, which will cause serious local pollution. Most of the existing domestic or imported printing machinery is not equipped with corresponding purification devices when leaving the factory. The atmospheric environment will cause harm to the urban environment and human survival that cannot be ignored.

The modernization, aesthetics and branding of contact materials have made the use of printing inks more and more widely. Almost all food packaging is inseparable from the decoration of printing inks, but printing inks contain a lot of toxic and harmful chemicals. These include: heavy metals, residual solvents, organic volatiles, and polycyclic aromatic hydrocarbons.

Therefore, the safety of food packaging is an indispensable part of food safety, and the hygiene and safety of printing ink is directly related to food safety and people’s health. Especially food packaging with plastic as the base material (including paper-plastic composite, aluminum-plastic composite and other composite food packaging materials) has a certain moisture and oxygen permeability, and the chemical migration of printing ink, resulting in food packaging. Harmful substances in printing inks contaminate food contents.

Solvent residues such as toluene in inferior printing ink products are as high as 151mg/m2 (my country’s requirement for food packaging is that the total amount of solvent residues is ≤10mg/m2), and the “soluble” lead content is as high as 430mg/kg (the European Union and other developed countries have a high demand for printing inks, coatings, etc.). and other products, the “soluble” lead content limit is less than or equal to 25mg/kg). The harmful substances that may exist in printing inks used in food packaging materials are related to the types of printing inks used. The printing inks used for food packaging mainly include resin-based printing inks (multi-finger offset printing inks) and solvent-based printing inks. Among them, solvent-based printing inks include benzene-soluble printing inks, alcohol-soluble printing inks, and water-soluble printing inks. These two types of printing inks have safety hazards such as heavy metals, soluble heavy metals, organic volatiles, and solvent residues.

Although my country has begun to vigorously advocate the use of alcohol-soluble printing inks and water-based printing inks, problems such as cost, printing process, printing speed and printing quality cannot be solved well. Therefore, solvent-based printing inks are still the mainstream of food packaging in my country. product.

Regulations on hygiene and safety of printing inks for food packaging

As we all know, when the printing industry and the food industry intersect and penetrate each other, “safety” has become an indispensable keyword. Benzenes have always been recognized as carcinogens, but benzene is also a good solvent for resin materials. It has the advantages of strong solubility, fast volatilization and low price, so it is widely used as a solvent for resins. Mainly used as a solvent for composite packaging material adhesives and plastic printing inks.

Ink is mainly composed of pigments, binders, auxiliary agents, auxiliaries, etc. Among them, pigments and binders are the most likely to cause environmental and safety problems. There are two kinds of pigments in ink, namely inorganic pigments and organic pigments, which are insoluble in water and other media, and have bright color and stability. Some inorganic pigments contain heavy metal elements such as lead, chromium, and mercury, which are toxic to a certain extent; organic pigments contain benzidine, which contains carcinogenic components.

In addition, most of the connecting materials of traditional inks are organic solvents, which are quite volatile and affect the printing working environment. If the ink containing heavy metals or aniline and other substances is used, the residual toxic substances in the printed food packaging bags will cause food contamination in the bags, which will affect the hygiene and safety of food and damage human health.

Therefore, the safety of food packaging is an indispensable part of food safety, and the hygiene and safety of printing ink is directly related to food safety and people’s health. In recent years, food safety problems caused by food packaging have emerged one after another, many of which are directly related to ink, an important packaging material. The “Food Safety Law of the People’s Republic of China” clearly puts forward requirements for food packaging materials and containers, which has a significant impact on ink manufacturers, food packaging printers and consumers. The use of green ink has become the only way for environmentally friendly printing.

At present, the European Union, the United States, Japan and other countries and regions already have regulations and laws on the hygiene and safety of printing inks, such as Japan’s NL regulations (self-restrictive regulations on printing inks for food packaging materials), German packaging law standards for printing inks The rationality of the ink is given.

Regarding export packaging materials that come into contact with food, there are many relevant decrees in the EU, such as vinyl chloride monomer in polyvinyl chloride (PVC), chlorinated biphenyls (PCB) in paper products, soluble and volatile in adhesives and printing inks Sexual substances and harmful heavy metals are listed as restricted materials in food, medicine and packaging of products that may come into contact with children.

Currently, the United States differs from the European Union in the amount of migration of packaging materials. The U.S. Food and Drug Administration stipulates that if a substance is not routinely analyzed as a food component, then it is not evaluated as an additive. At the same time, it is stipulated that according to the toxicity of the substance and the different packaging objects, the standard of migration is 10 to 50 ppb (ppb is one billionth). EU law requires that the migration of plastic packaging materials to it should not exceed 1mg per 1kg of food.

At present, the European Union, the United States, Japan and other countries and regions have formulated laws and standards on the hygiene and safety of printing inks on food contact materials, toys and other products. Printing inks used as packaging products may directly contact food, people, especially children’s skin (such as children’s licking, touching), etc., which can easily cause harm to the human body. The new requirements issued by the European Union intend to add printing inks to the content of materials and products controlled by specific regulations. my country’s food packaging and related food export enterprises should be cautious. In recent years, due to the high residual amount of harmful substances in food packaging, food contamination and poisoning have occurred frequently, which has brought many unfavorable factors to the creation of a harmonious society. The main reason for unqualified food packaging is that benzene residues exceed the standard. Benzene substances can damage the nervous system and hematopoietic function of the human body. The US FDA lists it as a carcinogenic chemical.

Therefore, in developed countries such as the United States, Western Europe and Japan, it is expressly stipulated that the use of benzene-based solvents in food packaging and printing is prohibited. In the absence of management and supervision, benzene-based solvent-containing inks are also commonly used in the production of food packaging composite films. In order to reverse this situation as soon as possible, my country’s first general national standard for regulating food packaging – “General Principles of Composite Films and Bags for Packaging” has been formulated and will be promulgated and implemented soon.

The “General Rules” has made new regulations on solvent residues, and the individual standards for benzene-based solvent residues are more stringent. It is stipulated in GB10005 “Biaxially oriented polypropylene/low density polyethylene composite films and bags” that the total amount of solvent residues should be ≤10mg/㎡, of which benzene residues should be ≤3mg/㎡; while in the “General Rules”, solvent residues The total amount remains unchanged, but the benzene residues are revised to ≤2mg/㎡. This modification reduces the harm of benzene to the human body to a lower level. In recent years, with the gradual popularization of the concept of “people-oriented”, as well as the advancement of testing technology, the media has been widely publicized, and the impact of food packaging on food quality has gradually become known to people.

my country’s implementation of the QS access system for the food packaging industry will inevitably lead to a major change and reshuffle in the food plastic packaging industry. monitoring and punishment. With the deepening of the national energy conservation and pollution control policy, small workshop-style enterprises will be eliminated, and large-scale manufacturers may take this opportunity to a new level.

The development trend of packaging and printing materials is to choose pollution-free packaging materials that are energy-saving, low-consumption, non-toxic, non-polluting and easily degradable, and ink is the raw material that causes serious pollution. Therefore, the use of green ink is the responsibility of every manufacturer. .

Environmental protection issues are becoming more and more important, and food safety has become the focus and urgent task of global attention, and has become the criterion for the development of environmentally friendly inks. Today, with the increasing awareness of environmental protection, people have higher standards for the development of ink. my country’s packaging and printing must unswervingly take the road of green development. The general trend of ink environmental protection is to take the green development road. Ink manufacturers are the source of ink environmental protection. Many manufacturers have already seized business opportunities, actively responded to the food safety law and market demand, and constantly revised their market positioning before the green benchmark. They chose non-toxic or non-polluting substances as formulas to produce environmentally friendly inks, which also brought them the benefits. Opportunities and vitality, but also improve the technical content, introduce new technologies, and adapt to different new materials.

With the gradual increase in the output of wax for offset printing ink, the production process of offset printing ink is gradually developing in the direction of automation. Through the introduction of advanced equipment, the control level of my country’s ink production process has been improved; by increasing the output of a single batch of ink, the consistency and stability of ink quality have been improved. .

As one of the raw materials of offset printing, offset printing ink must maintain its own advantages, and at the same time absorb and learn from foreign advanced experience, and improve the technical level of offset printing ink production and equipment in my country by introducing advanced technology and equipment; to improve the quality grade of offset printing ink , to establish color standardization of ink products, and work hard for the rapid development of my country’s ink industry.