- Polyethylene (PE) is a polymer made of ethylene by polymerization. PE is used in many forms of flexible protective packaging, including shrink wrap and stretch wrap, and the performance of each package varies greatly.
- PE can take many forms, but the three most common are low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE) and high-density polyethylene (HDPE). Each of these is best used for different industrial applications, but for shrink wrap, LDPE is the most common form.
- The benefit of using LDPE compared to other forms of shrink wrap is that it can increase strength and durability for heavier, larger items such as beverage multi-packs. These packages can also be printed, and excellent graphics can be added while still maintaining the image and the desired intensity.
- PE film thicknesses are typically 40, 60, 80, 100 and 120 microns. The disadvantage of PE shrinkage is that the shrinkage rate is not high, usually no more than 20%, and the transparency is much lower than other wrapping paper
- Polyethylene is divided into high-density polyethylene, low-density polyethylene and linear low-density polyethylene according to the polymerization method, molecular weight and chain structure.
- 低密度聚乙烯(LOW DENSITY POLYETHYLENE，LDPE)俗称高压聚乙烯，因密度较低，材质软，主要用在塑胶袋、农业用膜等。
- High density polyethylene (HIGH DENSITY POLYETHYLENE, HDPE) commonly known as low-pressure polyethylene, compared with LDPE and LLDPE, has a high temperature resistance, oil resistance, steam permeability resistance and environmental stress crack resistance, in addition to electrical insulation and impact resistance and cold resistance is very good, mainly used in blow molding, injection molding and other fields.
- LINEAR LOW DENSITY POLYETHYLENE (LLDPE) is a copolymer formed by the polymerization of ethylene and a small amount of high-grade olefins in the presence of a catalyst. LLDPE is similar in appearance to LDPE, with poor transparency, but good surface gloss, low temperature toughness, high modulus, bending resistance and stress crack resistance, and better impact strength at low temperatures.
̈LDPE (Low Density Polyethylene) – Low melting point, good tensile and strong – is commonly used in food and meat products as well as for stretch packaging/palletizing
̈LLDPE (Linear Low Density Polyethylene) - thinner than LDPE, high strength, good transparency - for bulk food, frozen food, prints, groceries, garbage bags, palletizing/stretch packaging
̈HDPE (High Density Polyethylene) - one of the most common polymers in plastic packaging - USDA/FDA approved for food contact, light weight, durable, water resistance, poor O2 corrosion resistance - suitable for certain food, retail products, clothing, stretch packaging trays
¨ Often suitable for beverage packaging can replace corrugated paper
̈ More expensive, but more durable
¨Polyethylene shrink film is recyclable
¨ thicker - provides greater stretch capacity
