High quality plastic materials and applications of

2022-09-19
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High quality plastic materials and applications for food packaging (II)

II. High quality plastic materials for food packaging 1. Metallocene polyolefins

metallocene is an organic metal coordination compound formed by the connection of transition metals and cyclodienes. Metallocene polyolefins are polymers prepared by olefin polymerization with metallocene coordination compounds as catalysts. Compared with traditional materials such as thermoplastics and elastomers, glass, paper and paperboard, and metals, metallocene and single center polymers have obvious advantages in processability and performance. Metallocene polymers have many advantages, such as good processability, high strength, high rigidity and good transparency, so they have attracted people's attention and many new varieties have been introduced. Metallocene plastics have good gloss, high melt strength and good film stability, and are suitable for the field of food packaging. Metallocene plastics will have subsidiaries in more than 60 countries to impact PP, mkpe, llkpe, elastomer and other plastic markets

in the contemporary injection molding process, countries are replacing LLDPE, PP, EVA and PVC with VLDPE (very low density polyethylene). This copolymer of ethylene and butene has the characteristics of rubber and plastic. It is a thermoplastic elastomer with very high flexibility and resilience. Blending with polyethylene and polypropylene resin can significantly improve the impact strength. At the same time, it has the characteristics of high melt strength and soft handle, and can maintain good tensile strength and elasticity in a wide temperature range. When VLDPE is used to produce single-layer film and coextrusion film products, it can improve the toughness of the film, and improve the speed and efficiency of film blowing under the conditions of users' original equipment. Blending with other polyolefin polymers can improve the tensile strength, tear resistance and impact resistance of products. At the same time, it can eliminate the stress whitening phenomenon in plastic products, increase the skid resistance and improve the surface hand sensitivity. In extrusion, injection molding and blow molding, VLDPE UK National composite center paves the way for mass production, which will impact the field of food packaging. Experts believe that the development of the plastic industry in the contemporary world focuses on plastic modification, coating of plastic products, rapid biodegradation of plastic and recycling of plastic. Some European and American manufacturers have produced PA bags with linear alkene, alkene copolymer, alkene acetic acid and alkene copolymer. The products are suitable for packaging ice cream, creamy and other foods

at present, the demand for polyethylene (PE) in the world market is 40million tons, which is expected to increase to 50million tons by 2005. Most of the increase is metallocene polyene. It is estimated that by 2006, the polyolefin produced by metallocene and single center catalyst will account for 10% of the total polyolefin market, twice the share in 2001. At the same time, film and sheet, especially packaging film, are still its main market, and the total demand in 2006 will reach 1.18 million tons, twice as high as now. The main products used include: stretch film, shrink film, wrapping film, garbage bags, heavy packaging bags and packaging films for meat, dairy products, fruits and frozen food. The European sales volume of metallocene polypropylene (MPP) will increase from 20000 tons in 2002 to 500000 tons in 2005, and the global sales volume will reach 5million tons. The latest research report "metallocene and single center polymer" of the American consulting company Freedonia group predicts that the average annual growth rate of polymer demand produced with metallocene and single center catalyst will exceed 20% before 2006, and the total turnover in 2006 will reach 5billion US dollars

2. OPP

influenced by the international packaging trend, domestic beer and beverage manufacturers began to use plastic film packaging in the process of product combination packaging, gradually replacing the traditional carton packaging and plastic turnover boxes. Among the numerous plastic films at present, oriented polypropylene (OPP) films have sprung up, and the demand is showing a rapid upward trend. Oriented polypropylene film can be used as a packaging material for labels and various consumer goods, such as fast food, candy, soft drinks and baked goods. It can meet various requirements, and has excellent printing performance, mechanical processing performance and moisture and light resistance

an OPP film with more scientific and technological content and higher process production level has been put on the market, bringing new highlights to the packaging industry and adding new vitality to the market. The new OPP is made of three layers of film, and its bottom layer adopts advanced steam fumigation technology to make it silver and bright on the surface; The middle layer provides a basic surface for printing, and after special processing, it can provide a reliable guarantee for printing directly on OPP film; The top layer is the printing surface, which can be 1 The industry chain develops 16 colors of direct overprint. The new OPP film has the advantages of good sealing, strong anti-counterfeiting and harmless

according to PCI film company, the global OPP market demand will increase at an average rate of 7.7% before 2007, which belongs to the category with fast growth in film products. Now OPP film is used more and more widely in the field of flexible packaging, and may replace the use of paper, sprayed metal film and aluminum foil, and its market demand will continue to grow. The development of packaging market in Southeast Asia will promote the growth rate of OPP demand in this region to be higher than the world average growth rate, reaching 10%. The demand for oriented polypropylene film in Western Europe will increase at an average annual rate of about 5%, reaching 1.1 million tons by 2007; The growth prospects in Eastern Europe are good. In 2007, the demand will reach 124000 tons and the production capacity will reach 157000 tons/year. The directional polypropylene film industry will strengthen rationalization and reorganization, and European companies are likely to acquire or participate in Asian companies

China's production capacity of oriented polypropylene film will increase significantly, accounting for 29% of the world's total production capacity by 2007, and its impact on the world market will be increasingly significant. China will increase exports to Southeast Asian countries and North America, and the balance of supply and demand will likely be broken, and the price will show a downward trend

(to be continued)

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