Flexible packaging technology and application of t

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Food flexible packaging technology and its application (II)

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

(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 contractibility - the shrinkage rate is 5% ~ 20%, and has thermal stability on November 24, 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

4. PVDC casing film

pvdc is a high barrier material with good properties of gas resistance, moisture resistance, oil resistance and chemical resistance. Homopolymer PVD Canada Magna International company introduced the concept car "MMLV (multi material lightweight vehicle)" C using multiple lightweight materials, which has poor compatibility with plasticizers and stabilizers, and is a kind of heat sensitive plastic, so it is difficult to form it by melting processing. Commercial P has built a series of copper-clad aluminum flat bars and demonstration production lines. VDC resins are PVDC copolymers modified with vinyl chloride or acrylic monomers. Although the compatibility of PVDC with plasticizers and stabilizers is improved through copolymerization modification, when used as a high barrier material, the addition of plasticizers, stabilizers and other additives is still strictly limited (the addition of additives will significantly reduce its barrier property), so 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

5. Pearlescent film

pearlescent film has milky pearl color. It is a BOPP film produced by adding pearlescent pigment into plastic particles and heat setting by biaxial stretching. Because the film has a special pearl like luster after surface printing, it is widely used in food packaging such as ice cream, popsicles, candy, snacks and so on

a typical pearlescent film is BOPP pearlescent film produced by a/b/a3 layer coextrusion biaxial stretching method, in which B is polypropylene mixed with pearlescent masterbatch, and a is a PP copolymer that varies with the surface properties of pearlescent film, with good heat sealing property. Biaxial stretching is carried out below the melting point of material B and above the melting point of material a

because there are many pearlescent inorganic pigment particles in material B, the result of biaxial stretching is that polypropylene molecules are oriented along the direction of external force, and the distance between pearlescent pigment particles is widened to form pores, making layer B become a mechanically foamed foam. Therefore, the pearlescent film of a/b/a structure is a kind of biaxially stretched BOPP foam plastic film, and its specific gravity is smaller than that of general BOPP film, which is only 0.7 ~ 0.75, while the specific gravity of general BOPP film is about 0.9

a material layer has the function of protecting B material layer in BOPP pearlescent film, and endows the pearlescent film with certain heat sealing property. Therefore, the pearlescent film with a/b/a structure has good heat sealing property. The pearlescent film produced only with material B can only rely on the porosity of the film and the slight heat sealing of a small amount of non oriented PP molecules. The pearlescent film after heat sealing is easy to tear off

6. Thin food packaging paper

as a paper for special purposes, thin food packaging paper must meet the following requirements: ① production water must comply with GB5749 sanitary standard for drinking water; ② Fluorescent brighteners and chemical additives harmful to human body shall not be used; ③ Pipes must be stainless steel or plastic steel pipes; ④ The raw materials used in the paper production process must be pure bleached coniferous wood pulp, self-made natural color or bleached long fiber Bast Pulp and hemp pulp, and waste paper, straw pulp and other moldy pulp are not allowed; ⑤ Workshop hygiene and personal hygiene of employees must comply with gb15979 hygienic standard for disposable sanitary products

the raw materials and their proportions used in the production of paper are also different with the contents of the package. For example, the proportion of bast fiber should be larger for food bag paper with higher requirements for tensile resistance; The packaging paper used as the inner bag of drugs only requires good antibacterial, moisture-proof and sealing properties, and does not require high paper strength. 100% bleached coniferous wood pulp can be used. At the same time, the amount of additives should be larger, while the amount of surface sizing should be smaller

thin food packaging paper not only requires that it can withstand large tension and tension under extremely thin conditions, but also has oil resistance 3 In the process of transportation, it has special properties such as waterproof, moisture-proof, heat-resistant and easy to adhere

(to be continued)

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