Application of the hottest flexible packaging in f

The application of flexible packaging in food industry (I)

flexible packaging has several remarkable characteristics: light, convenient, strong and beautiful. The so-called light, that is, the weight of the packaging itself is light; Convenient, that is, convenient to use; Strong, that is, it is not easy to break and can withstand extrusion; Beauty refers to the variety of styles and the beauty of printing patterns, which can increase the aesthetic feeling of goods

first, the market share of food flexible packaging is gradually increasing

with the continuous improvement of materials and processing technology, flexible packaging plays an increasingly important role in China's food industry. By 2002, the sales of flexible packaging had accounted for 56% of the sales of packaging in China's food industry

in terms of perishable food packaging, the flexible packaging of meat food, agricultural products and other frozen food is the fastest growing. These perishable foods are usually packed with high-capacity vacuum films. Among them, the main raw materials used in bagged meat food include clean and anti fog packaging materials, high barrier films and widely used shrink films. In 2002, in the field of fresh meat packaging, more than 30% used bag packaging

with the best-selling of smoked sausage for banquet and breakfast, the demand for its packaging film will increase at a rate of 9% per year, becoming the fastest-growing part. Metallocene is becoming a new favorite of sealing materials. Although the number of people who eat high-fat foods and breakfast is decreasing, new flavors and low-fat foods still help to promote the demand for packaging films

some other important food flexible packaging markets include Cereals, pet food and coffee. The fastest-growing flexible food packaging is the small packaging used for food with a price of about $5. Most of this kind of food will be placed prominently in the passageway of the supermarket, the cashier's office or the location of special food in the convenience store to stimulate consumers' desire to buy

it is very necessary to print novel patterns on the packaging, which can often trigger people's desire to buy, such as candy. Many foods also require good moisture resistance in packaging

candy is the field with the highest profit margin, and will continue to grow at a rate of about 5%. As the amount of candy purchased by consumers on impulse exceeds 70% of the total sales of candy, novel packaging and high-quality printed patterns, especially metallized patterns, are increasingly used in candy packaging. The growing new market of low-fat candy also helps to promote the development of flexible packaging industry

more expensive packaging materials are gradually used for high-end pet food, which accounts for an increasing share in the flexible packaging market. Because these foods contain more expensive and oxygen sensitive ingredients, they need better packaging to protect them

II. Introduction to food flexible packaging materials

the primary function of new flexible packaging materials is to ensure the quality of food. Therefore, the functional characteristics of blocking water vapor and oxygen, no bubbles in winter, not easy to break, high temperature resistance (sterilization), agitation resistance in use, suitable for microwave heating, economical and practical, and conducive to sales are all very important

1. High barrier film - notran film

notran film is a multi-layer structure film extruded by nylon or EVOH (high barrier) with strong gas barrier and polyolefin resin with strong heat sealing and water barrier. Notran film can block oxygen, flavor, solvents, etc. its purpose is to improve the storage of contents. It is mainly used to package meat processing products (such as ham, sausage, clam slices), fresh meat, cheese, salad dressing, sauce foods, pickles, agricultural products and seafood

the main functions of the barrier gas film are:

(1) prevent oxygen and other gases from entering the package to avoid causing microbial reproduction in the package

(2) prevent the oxidation of package contents caused by oxygen penetration

(3) prevent the escape of fragrance, solvent, etc

(4) replace packaging and vacuum packaging with gases (nitrogen, carbon dioxide, oxygen) to prevent gas leakage in the packaging or external gas entering the packaging

2. The eccentric load of the tensile testing machine severely affects its normal operation. Evaporated PET film

silicon oxide evaporated PET film has safety barrier property, but once it is subjected to external forces such as tension, thermal vibration and bending in the process of processing, use or circulation, the evaporated coating will be damaged, which greatly reduces the barrier capacity. At present, researchers are researching and developing evaporation coatings with stable performance to try to change this situation

3. Yibaolong nylon casing

the sausage sold on the market now generally adopts the new generation of nylon casing - yibaolong nylon casing. This is a new 5-layer seamless biaxial stretch shrink nylon casing, which was originally specially designed to meet the needs of the Australian market. Yibaolong casing has the following characteristics: high precision, good performance, and real-time display of experimental data

(1) impermeability - it can maintain the flavor of meat products during cooking and maintain the characteristic flavor of meat products to the greatest extent

(2) high barrier - it can prolong the shelf life of meat products and reduce weight loss during cooking

(3) high strength - resistant to soaking and not easy to crack during filling

(4) good meat viscosity - avoid the gap between meat products and casings, which will lead to the decay of meat products

(5) good shrinkage - the shrinkage rate is 5% - 20%, and it has thermal stability, so it is not necessary to carry out late shrinkage (it is not necessary to immerse in the warm water pool to remove wrinkles). The casing will not wrinkle after cooking and cooling

(6) high temperature resistance - the cooking and disinfection temperature of sausage can reach 120 ℃

(7) low temperature resistance - the refrigeration temperature can be as low as 2 ℃

(8) can be accurately controlled - the casing diameter has an error of ± 1mm

(9) easy to peel - casings are easy to peel from meat products

(10) good chemical stability - good resistance to oil, fat, grease, meat acid and solvents

pvdc is a high barrier material with good properties of gas resistance, moisture resistance, oil resistance and chemical resistance. Because homopolymer PVDC has poor compatibility with plasticizers and stabilizers, and it is a kind of heat sensitive plastic, it is difficult to form it by melting processing. Commercial PVDC resins are PVDC copolymers modified with vinyl chloride or acrylic monomers. Although the compatibility of PVDC with plasticizers and stabilizers is improved by copolymerization, when used as a high barrier material, The amount of additives such as plasticizers and stabilizers is still strictly limited (the addition of additives will significantly reduce their resistance, and focus on the development of low-cost preparation technology of spherical powder of special alloys such as high-speed steel, die steel, stainless steel, high-quality titanium alloy, superalloy, aluminum alloy, copper alloy, which can lead the wide use of additive manufacturing technology). Therefore, the temperature control of its processing process is quite strict. Therefore, the domestic equipment for processing PVDC is imported, and the PVDC particles used also rely on imports. At present, China has introduced nearly 20 PVDC casing film production lines from the United States, Japan and other countries, such as Tianjin No.2 plastic factory, Xingtai plastic factory, and some enterprises in Handan, Luoyang and other places

pvdc casing film is smooth and flat, and the thickness is generally 15 ~ 20 μ m. The transparency is good, but at present, red pigment is generally added, so it can only be printed on the surface. In order to make the printing ink layer of PVDC casing film have good adhesion fastness and high temperature cooking resistance, PVDC special ink must be used. The surface printing ink and composite inner printing ink used in soft plastic packaging printing cannot meet the printing requirements of PVDC casing film