Application of Polyurethane Adhesive in Food Packaging Industry

At present, although the overall development trend of adhesives is non-organic solvation, polyurethane solvent-based adhesives, due to their excellent process and adhesive properties, especially non-organic solvent-based adhesives, cannot fully meet the solvent-based level at present, and solvent-based polyurethanes. The adhesive will still be present for a longer period of time.

In Europe, the United States, Japan and other developed countries or regions, the use of solvent-based polyurethane adhesive in the field of dry compounding more than 60%. Since 1980, China has begun to introduce Japan's composite film production technology and equipment, and it is estimated that the dry film production line will have more than 300 lines and the polyurethane adhesive will use more than 35,000 tons per year. The solvent-based two-component polyurethane adhesive that was first applied to the composite packaging industry in China was produced by the Beijing Chemical Industry Research Institute in 1984 from the former West Germany. The main product is a low viscosity, high solids (75%) polyurethane adhesive. Since then, various types of domestic composite equipment have entered the market, and domestic manufacturers and research institutes have successively developed a variety of compatible solvent-based two-component polyurethane adhesives, mainly low solids (15 to 50%) and high-viscosity products.

In general, low-viscosity, high-solids products can be coated at a high concentration of 40% or more because of their low viscosity, low solvent consumption, environmental friendliness, low overall cost, high transparency, and good strength of the products. Equipment, processes, and raw material control all have higher requirements, and various defects such as poor strength are likely to occur when the application is not appropriate. This product is suitable for use in a composite manufacturer with a certain scale. Low solid content (15 ~ 50%), high viscosity product with high initial adhesion, good adaptability to domestic composite machine, but less transparency, too much solvent, unfriendly to the environment, high overall cost, such products Suitable for medium and small scale composite manufacturers.

At present, from the perspective of China's overall adhesive market, it has the following characteristics:

Multinational companies are promoting both functional and non-organic solvent-based products in China, seizing high-end markets, and direct-selling or co-production of ordinary polyurethane adhesives to compete for the general market. Domestic enterprises, after years of digestion and absorption and independent development, many companies have mastered ordinary polyurethane adhesive production technology and production, the current production is estimated at 30,000 tons / year, about 30 species, these manufacturers become the main raw material suppliers. Some domestic companies with strong technical capabilities have been able to produce high-performance functional or non-organic solvent-based products. Domestically produced functional solvent-based adhesives, such as high-temperature cooking type, media-resistant type, and anti-slippery type, have come out one after another to make up for the gap. In the area of ​​non-organic solvent type polyurethane adhesives, despite the introduction of new products, there is a certain gap between process operation and application performance and solvent-based products, and the cost is also at a disadvantage, and the application and promotion situation is still relatively high compared with developed countries. Big gap.

With China's accession to the WTO and the improvement of domestic environmental awareness, technical barriers such as environmental protection will be highlighted. Composite film manufacturers and adhesive manufacturers should work together to improve the technical level of composite products.

Comprehensive inspection and analysis of the current domestic polyurethane adhesive industry, regarding the next development of polyurethane adhesives, we believe:

(1) The production technology of domestic solvent-based two-component polyurethane adhesives for general composites has been fully understood. Some manufacturers have mature technologies and stable quality, which can completely replace imported products;

(2) The production technology of solvent-based two-component polyurethane adhesives for retort cooking of some domestic manufacturers has passed. Many years of popularization and application show that the product quality is stable and the price is reasonable, and it can already replace imported products;

(3) Aluminized film special glue, anti-sliding agent functional rubber and other products have strong pertinence and outstanding performance and should be vigorously promoted;

(4) The climate in China is obviously different, and the status of the composite equipment is different. The composite manufacturer should select the applicable adhesive type in a targeted manner;

(5) China has joined the WTO. Compound manufacturers should pay attention to improving technology, renewing composite equipment, promoting with environmental friendly adhesives, breaking environmental protection technology barriers, and adapting to the requirements of globalization;

(6) Adhesive development units and manufacturers should speed up the development of environmentally friendly alternatives so that the overall product performance meets the composite requirements;

(7) Industry associations should improve product inspection methods and methods, accelerate the formulation of product industry standards, establish technical barriers, and protect national industries.

With the continuous development of the Chinese economy and the continuous improvement of people’s quality of life, the demand and choice of adhesive products will become more and more strict and demanding. Those products with good performance, high quality, and environmental protection will be favored by people. Chinese adhesives manufacturers and research institutes should increase investment in science and technology in accordance with market demand, and actively research and develop high-performance, high-quality adhesive new products to cope with competition in domestic and foreign markets.