“EPP (expanded polypropylene) is a unique raw material that has many important characteristics making it suitable for a wide range of applications. Some striking selection criteria are: energy absorption, low weight and high thermal stability.”

 

1. What is EPP?

“EPP (expanded polypropylene) is a unique raw material that has many important characteristics making it suitable for a wide range of applications. Some striking selection criteria are: energy absorption, low weight and high thermal stability.”

2. EPP Performance

EPP (expanded polypropylene) is a unique raw material that has many important characteristics making it suitable for a wide range of applications.  Some striking selection criteria are: energy absorption, low weight and high thermal stability.

  • EPP is in particular used for expensive and vulnerable electronics products or molded parts, such as climate-control and automotive industries parts.
  • Despite its low weight, EPP can absorb large amounts of energy and has a remarkable ability to restore its shape after being subjected to static or dynamic loading.
  • The deformation is very balanced, independent of the direction of the impact/ load.
  • EPP is temperature resistant, absorbs hardly any water and is effectively resistant to chemicals and oils.

3. EPP Character

 
  •  High energy absorption and lightweight product
  • Excellent repetitive impact performance
  • Excellent temperature resistance
  • Durability
  • Recycled content
  • Low/zero air emissions & hazardous substances
  • Easy, non-hazardous maintenance
  • End-of-life management keeps materials out of landfills (e.g., reuse, recycling, return to manufacturers)
  • Nontoxic and food safety
  • Low life cycle cost
  • Excellent oil and chemical resistance, weather resistance
  • Flexibility makes it easy to handle products
  • Remarkable ability to restore its shape after static and dynamic loading
  • Possible to recycle by non-crosslink (reduction facility)
  • Choice of various expansion ratio (raw material supplier)
  • Excellent dimensional accuracy
  • It has low water absorption
  • Excellent insulation performance
  • Environmentally friendly

4. EPP Product Manufacturing Process

EPP is cell polypropylene that is prepared by cutting suitable length granules from polypropylene after the extrusion process. After cutting, the EPP granules are pre-expanded in the process, the active ingredient of which is CO2.  EPP products are produced in a molding machine, where they shaping and will receive their final shape during the oven hardening stage.

5. EPP Bead Production Process

      EPP beads are made in two process steps. The first step is a mini-pallet with an extrusion compounding process, and the second step is a high-temperature, high-pressure and CO2 gas firing process in the autoclave. In order to make the resulting PP granules expandable, they are suspended in water via high pressure (50 bar) and a high temperature (150℃), and impregnated with a blowing agent CO2. Carbon dioxide (chemical formula CO2) is a naturally occurring colorless gas with a density about 60% higher than that of air (1.225 g/L) that is odorless at normally encountered concentrations.

  • Mini Pellet Extrusion Line & Process

The mini pallet is made of random co-polymer polypropylene as a raw material. The first step in the production of EPP is the production of mini pallets by extrusion compounding process. In this process, additives are added to produce a very fine mini pallet of 0.5mm to 1.5mm size.

  • EPP BEAD PRODUCTION PLANT & PROCESS

In order to make the resulting PP granules expandable, they are suspended in water via high pressure (50 bar) and a high temperature (150℃), and impregnated with a blowing agent CO2.

6. Price analysis of EPP and EPS

PP raw material price is cheaper than PS price. Why the foamed EPP price much higher than the EPS price?

EPP producers purchase EPS mini pellets and directly produce the EPP bead in their plant and through this EPP producers can reduce big amount of material cost and shipping costs.