How to Tell the Difference Between Various Types of Plastic Film

In our daily life and industrial production, plastic films are everywhere. From food packaging to agricultural greenhouses, from electronic product insulation to building material protection, plastic films play an indispensable role. However, there are many types of plastic films, the most common of which are polyethylene (PE) film, polyvinyl chloride (PVC) film, polypropylene (PP) film, polyester (PET) film, etc., which differ in appearance, performance and use. So, how to accurately distinguish these different types of plastic films?

1. Transparency 

 

• PE film
  It is usually translucent or slightly transparent, with a soft luster and relatively low transparency, especially high-density polyethylene (HDPE) film.
   
• PVC film
  It has high transparency and can achieve a crystal clear effect, especially PVC film with no plasticizer or low plasticizer content.
   
• PP film
  It has high transparency, good gloss, and looks brighter.
   
• PET film
  It has extremely high transparency and is one of the most transparent common plastic films, with a smooth surface and good gloss.

2. Color

 

• PE film
  Generally colorless or white, and can also be made into various colors by adding masterbatch, but the color is relatively soft.
   
• PVC film
  Can be made into various bright colors, rich and varied colors, and there are also transparent and colorless products.
   
• PP film
  Usually colorless, transparent or white, it can present different colors after adding masterbatch, and the color is relatively bright.
   
• PET film
  Generally colorless and transparent, and some of them present specific colors after special treatment or adding additives, such as black, blue, etc., but not as rich in color as PVC film.

• PE film: soft texture, with a certain elasticity, feels smooth to the touch, and is not easy to generate static electricity.
• PVC film: The softness of the feel varies depending on the plasticizer content. PVC film with a high plasticizer content is soft and elastic, similar to rubber; PVC film with a low plasticizer content is relatively hard.
• PP film: hard texture, brittle feel, lack of elasticity, but has good stiffness, feels dry to the touch, and is easy to generate static electricity.
• PET film: stiff feel, smooth surface, with a certain hardness and rigidity, not easy to deform, and feels high strength when stretched.

• PE film: easy to burn, the flame is blue when burning, with yellow on the top, it will melt and drip when burning, and it has the smell of burning paraffin.
• PVC film: difficult to burn, extinguishes immediately when away from the fire, the flame is yellow when burning, with green edges, white smoke, and a pungent smell of hydrogen chloride.
• PP film: easy to burn, the flame is yellow when burning, there is a small amount of black smoke, it will melt and drip when burning, and it has a smell similar to petroleum.
• PET film: The flame is bright and there is black smoke when burning. After burning, it will leave black residue with a special aroma.

• PE film: The density is generally between 0.910-0.965g/cm³. The density of different types of PE is slightly different. HDPE has a higher density and LDPE has a lower density. The film can be placed in water, and the PE film will generally float on the water surface.
• PVC film: The density is about 1.35-1.45g/cm³, which is heavier than water and will sink when placed in water.
• PP film: The density is usually between 0.89-0.91g/cm³. It is one of the common plastic films with lower density and will obviously float when placed in water.
• PET film: The density is about 1.38-1.41g/cm³, and it will sink when placed in water.

• PE film: It is widely used in agricultural covering, packaging (such as food packaging, daily necessities packaging), garbage bags and other fields.
• PVC film: commonly used in building materials (such as plastic door and window profiles), wire and cable insulation, raincoats, tablecloths, plastic film wallpaper, etc.
• PP film: widely used in the packaging industry, such as food packaging, textile packaging, cigarette packaging, etc., and also used to make labels, tapes, etc.
• PET film: mainly used in the electronic and electrical industry (such as insulating materials, membrane switches), packaging industry (such as beverage bottles, food packaging), photographic film and other fields.

• Infrared spectroscopy analysis
  Each plastic has its own unique chemical structure and chemical bonds. The infrared spectrometer can detect the vibration absorption peaks of various chemical bonds in the plastic film, thereby determining the type of plastic.
• Differential scanning calorimetry (DSC)
  Measure the thermal effect of plastic film during heating and cooling to obtain its melting point, glass transition temperature and other characteristic parameters. Different types of plastics have different characteristic temperature values, which can be distinguished accordingly.