Composite Packaging Adhesives Environmental Safety Issues

There are many factors to consider when selecting adhesives for food flexible packaging. In general, the following conditions should be met:

(1) Non-toxic; (2) No harmful extracts appear after packaged food; (3) Applicable temperature requirements for food storage; (4) Good weather resistance, no yellow foaming, no chalking and delamination; (5) Has a certain resistance to media; (6) does not erode the printing pattern ink, and has a higher affinity for the ink.

The adhesive for packaging composite films should also have the following properties:
(1) Adhesion: The adhesive must have the ability to simultaneously bond two different materials;
(2) Softness: Meet the requirements of flexible transportation and storage after compounding;
(3) Heat resistance: According to the food processing technology, there is a certain degree of heat resistance;
(4) Cold resistance: It can meet the requirements for low temperature storage of foods;
(5) Resistance to media: The stability of the adhesive is very important. It must be able to withstand the erosion of the media, otherwise it will cause the peeling of the composite film and lose the packaging effect.
(6) Safety and Hygiene: Meet the relevant standards for food packaging safety and health.

China has already had laws and regulations and corresponding hygiene standards for food and packaging materials. There are two of them: the First is the Food Safety Law of the People's Republic of China and the second is the Administrative Measures for Plastic Products and Raw Materials for Food. The "Food Hygiene Law" was promulgated by the State Council, and the "Administrative Measures" was promulgated by the Ministry of Health. Both of these are mandatory laws that violate their rules and regulations. The content of food hygiene regulations is much broader than the management methods and is a comprehensive law. The latter is professional, referring only to plastic products and raw materials. The scope of management is limited to various types of plastic food containers, containers, production management, conveyor belts, plastic packaging materials and synthetic resins used in the food contact. Agent.

There are two major series of alternatives to solvent-based adhesives.

One is a water-based adhesive. Advantages of water-based adhesives are: Viscosity does not change significantly with the change of the molecular weight of the polymer, which can quantify the polymer to increase its cohesive strength; the viscosity is generally lower than that of the solvent type; easy to mix with other resins or pigments Improved performance, reduced cost, non-flammable, non-toxic, suitable for substrates that are easily attacked by organic solvents, easy to formulate and easy to clean.

Water-based adhesives are mainly single-component and two-component products. The feature of the single-component series is that it does not require rationing when gluing and it is used directly. The operation process is simple, the cost is low, and the production efficiency is high. The advantages are more prominent in the composite properties of the film and the aluminized film, and do not cause the transfer of the aluminized film like the polyurethane adhesive. Due to the limitation of peel strength, one-component water-based adhesives are mainly used in light-weight packaging fields such as puffed foods, biscuits, candy condiments and pharmaceuticals. The two-component water-based adhesives overcome the technical problems of peel strength, heat resistance and chemical resistance, and can be used in packaging including cooking foods and liquid foods.

The second is a solvent-free adhesive. Solvent-free adhesives are basically also composed of two-component polyurethane adhesives, whose main agent and curing agent have higher viscosity at room temperature but still have fluidity and are semi-solid substances. When compounding is to be performed, the main agent and the curing agent are mixed in proportions, placed in an adhesive tray having a heat-retaining function, and the viscosity is lowered to an appropriate level by heating, and then passed through an anilox roller having a heat-retaining function. Go to the substrate. After coating, it is not necessary to heat and dry directly to compound with another substrate.

Rohm and Haas Company is the first multinational company to promote waterborne composite adhesives in China's flexible packaging market, and it is also the first company to commercially supply waterborne adhesives in the Chinese market. Rohm and Haas Company believes that the flexible packaging market in Europe and the United States currently uses water-based and solvent-free series. The development direction of China's flexible packaging market is undoubtedly more environmentally friendly and healthier. Rohm and Haas Company helps its customers to cope with future regulations.

At present, Rohm and Haas has accounted for about 90% of the global market for water-based adhesives in the flexible packaging industry. American Rohm and Haas company's water-based adhesives are mainly single-component and two-component two major product lines. One-component water-based adhesives are mainly used in light-weight packaging such as puffed foods, biscuits, confectionery condiments and the like. The two-component water-based adhesives overcome the technical problems of peel strength, heat resistance and chemical resistance, and can be used for high-end products such as steamed foods and liquid packaging. The adhesive layer of the water-based acrylic adhesive is both flexible and tough, and is particularly suitable for manufacturing various laminating composite films for food packaging. Many well-known domestic egg yolk pies, biscuits, instant noodles, cereals, and soy milk brands even specify that their packaging manufacturers use waterborne adhesives manufactured by Rohm and Haas. End-user support has accelerated the promotion of water-based adhesives in China.

Rohm and Haas committed itself to promoting the development of energy-saving, safety, and environmental protection throughout the entire industry chain. Through technical support and exchanges with food manufacturers, it has approved new environmentally-friendly packaging to promote the normal and healthy development of the industry chain. At the same time, Rohm and Haas has always paid attention to the voices of the environment, communities and consumers. It advocates moderate packaging and green packaging in the industry, and advocates that packaging should be based on practical environmental protection and safety and health, and pay attention to environmental protection and other social responsibilities.

Rohm and Haas Company is the world's largest manufacturer of acrylic emulsions and has invested in the construction of two acrylic emulsion production plants in Beijing and Shanghai, China. Rohm and Haas introduced the mature environmentally friendly water-based adhesive in the US market. It does not contain organic solvents, and its performance can fully meet the requirements of the film and film used in general food packaging. Dry compounding between film and aluminized film. Requires alternative solvent-based polyurethane adhesives and can be used directly on existing solvent-based dry scrubbers. Rohm and Haas company's raw materials for adhesives, such as monomers and intermediates, are self-manufactured and synthesized. A strong supply chain ensures the stability of raw materials. Rohm and Haas' advanced production processes and fully automated equipment make it the world leader in water-based adhesives. In addition, the use of this water-plastic composite packaging film can be cut immediately without curing, so it can reduce the production cycle for color printing manufacturers, especially in the busy season can easily deal with emergency orders of food manufacturers.

Reprinted from: China Packaging News