Packaging bag and its making method

Abstract

A packing bag for food is composed of a first film layer with several slits generated by calendering and a second film layer to interlock with several lateral edges of the first film layer. Its preparing process includes such steps as preparing high-molecular films, calendering, coating, hot pressing for enclosing edges, and cutting for removing excessive edges. It features that the food contained in it can be easily heated by microwave oven, high-temp. steam, boiling or infrared ray.

Description

1. Technical field: [0001] The invention relates to packaging supplies, in particular to a packaging bag and a manufacturing method thereof. 2. Background technology: [0002] At present, the more common packaging items used in microwave ovens on the market include plastic wrap (wrapfilm), special bags for microwave ovens, and dishes. The raw materials used in these packaging items are polyethylene (PE), polypropylene (PP), polythiamine (polyamide, nylon), polycarbonate (PC), polyvinyl chloride (PVC), polyvinylidene chloride (PVDC) , polymethylpentene (PMP), ethylene-vinyl acetate (ethylene-vinyl acetate, EVA), polyurethane (polyurethane, PU) or SurlynTM (trade name of Dupont ionomer ion polymer compound), polyethylene terephthalate Ester (polyethylene terephthalate, PET), polyvinyl alcohol (polyvinyl alcohol, PVA), paper, synthetic paper, cellophane, wax paper, ceramic, glass and other materials or a combination of the above materials, the structure of the packaging items ...

AI Technical Summary

Problems solved by technology

Although this method can produce micro pores, the manufacturing cost is too high and difficult, and there is still an explosion phenomenon in the heating process. Most of the inorganic salt additives added in it belong to a kind of low specific heat and high Materials with a dielectric constant are easier to travel to local hot spots in a heated environment, and because of the problem of melting through packaging materials, it is not practical

In addition, this method will lead to inconsistent quality of the breathable film, such as stretching ratio, processing temperature, film thickness and raw material formula, etc. will lead to inconsistent hole sizes, and the use of additives will have different effects on the subsequent environment, which may cause environmental problems

Furthermore, the multiphase combination (multiplephases) of additives often makes the film not possess transparency after film formation.

Also, when this material is used in food packaging, the additives in the material may contaminate the packaged food and cause unpleasant odours.

When this type of gas-permeable film comes into contact with food containing oil or alcohol, it cannot effectively block the oil and alcohol, and will cause the oxygen scavenger components in the food packaging to be contaminated by the oil or alcohol, and cannot achieve the function of keeping the food fresh

Images