Types, Characteristics and Applications of Vest Bags for Plastic Food Packaging Material

Release date:2019-09-28 14:19
When we walk into the supermarket's food counter, facing a wide range of delicate, diverse and well-packed foods, and pick up all kinds of fresh food, beverages, edible oils, vegetables, fruits and other foods in bags, boxes, bottles, etc. at random, food packaging has become an integral part of fast food and convenience food. Food packaging materials include paper, plastics, metals, ceramics and so on. Among them, plastic packaging materials have excellent properties such as anti-permeability, anti-ultraviolet, freezing resistance, heat resistance and so on. They play the roles of moisture-proof, fragrance-preserving, anti-oxidation and preventing food from being extruded.

Food plastic packaging materials mainly include the following varieties:

1) polyethylene

PE, for short, is non-toxic. It can be divided into high density (HDPE), low density (LDPE) and linear low density (LLDPE). HDPE has good hardness, air tightness, mechanical degree and chemical resistance. It can be used at higher temperatures. The hollow containers made of PE are widely used for food such as milk products, juice and jam. LDPE has good transparency, softness, high elongation, better impact resistance and low temperature resistance than HDPE, and is often used as thermal sealing and moisture resistant coatings of composites. LLDPE can also be made into film and film bags for packaging. Most of the plastic film bags we use in our daily life are made of this kind of material.

2) polypropylene

PP for short, high crystalline structure, permeability of polyethylene 1/4-1/2, high transparency, smooth, high processing performance. At present, the containers made of polypropylene coating film with good air tightness and easy thermal bonding and composite materials such as other films, cellophane, paper and aluminum foil can be used for beverage packaging. In addition, the microwave oven lunch box is made of PP, which can withstand high temperature of 130 C. This is the only plastic box that can be put into the microwave oven. It can be reused after careful cleaning.

3) Ju You Zhi

Abbreviated as PET, it has good crystallinity, colorless transparency, odorless, odorless, non-toxic and flammable, good air tightness and extremely tough material. In recent years, the production and use of PET bottles have developed rapidly. PET bottles have good transparency, high surface gloss and glass appearance, which can give full play to the characteristics of PET. Heat-resistant PET bottles are widely used in tea drinks, fruit juice drinks and other beverages that need hot canning.

4) Polyvinyl chloride

PVC, for short, is divided into three categories: hard products, soft products and paste products. Generally, plasticizers for hard products are less than 5%, and plasticizers for soft products are more than 20%. Rigid PVC contains no or little plasticizer, light weight, excellent mechanical strength, stable chemical properties, made of PVC capacity

It is widely used in beverage packaging, such as Coca-Cola. At present, most of the fresh-keeping films and food packaging boxes used in supermarkets are made of PVC.

5) Polyvinylidene chloride

PVDC is short for PVDC. It has soft and very low permeability. It can prevent odor from passing through. It has good freshness and fragrance retention. It is suitable for long-term preservation of food. In addition, it also has acid, alkali and chemical resistance, good oil resistance and heat shrinkage, and is a good heat shrinkage packaging material. Because PVDC is a high barrier transparent material certified by FDA in the United States, it is often used to make composite materials or PVDC coating materials with paper, aluminium foil and other plastic films such as PE, PP, PVC, PET, polyphthalamine (PA). These materials have excellent moisture-proof, oxygen-insulating and sealing properties, and are easy to heat-seal. They are suitable for packaging water-containing food. The disadvantages of PVDC are too soft, poor operation performance, easy cracking and perforation, poor aging resistance and toxicity of its monomer.

6) Purpose of polycarbonate

PC, for short, is colorless, transparent, non-toxic, odorless, smooth and beautiful, easy to shape, good heat resistance and impact resistance, good anti-ultraviolet transmission performance and moisture-proof and fragrance-preserving performance, not fragile at 1180 C, and can be used for a long time at 130 C. It is an ideal food packaging material, but its wide application is limited by its high price. Common drinking water cans and space cups are made of this kind of material.

7) Polystyrene

PS is colorless and transparent. It has excellent insulation, insulation and transparency, but it is brittle and easy to crack at low temperature. The glass transition temperature is higher than 100 C, so it is often used to make all kinds of disposable containers which need to withstand boiling water temperature, as well as bowl foam noodle boxes, disposable foam fast food boxes and so on.

8) polyphthalamide

Abbreviated as PA, commonly known as nylon, good mechanical properties, toughness and wear resistance, cold resistance, heat resistance, the use temperature is 160-130 degrees, up to 200 degrees Celsius. In addition, the chemical performance is stable, easy to process, good printing, excellent puncture resistance, but poor heat sealing, strong water absorption, and swelling with the increase of water absorption, which makes the gas and moisture resistance decline sharply, and its strength and packaging size stability are also affected. Most of the refined rice sold in the market is packaged in PA bags.
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