PP Polypropylene

1. Material Introduction

PP stands for Polypropylene. It is polymerized from propylene monomers with catalyst, chemical formula \(\boldsymbol{(C_3H_6)_n}\). It appears as white waxy translucent pellets with density of 0.89~0.91 g/cm³, the lightest among five general-purpose plastics.
Global annual output exceeds 80 million metric tons, ranking 2nd only after PE.
According to molecular structure, it is divided into 3 grades:

• - Homopolymer PP (PP-H): high rigidity
• - Block copolymer PP (PP-B): good impact resistance
• - Random copolymer PP (PP-R): high transparency

It is widely used in food packaging, automotive components, building pipes and woven bags.

2. Specifications & Grades

3. Chemical Composition & Properties

Reference Standard: GB/T 12670-2008 Polypropylene (PP) Resin

Chemical Composition

Physical & Mechanical Properties

4. Functions & Applications

Key Advantages

• - Density is only 0.89~0.91 g/cm³, lighter than water. For parts of equal volume, PP is over 35% lighter than PVC and over 25% lighter than ABS. It is adopted for automotive bumpers and instrument panels to reduce vehicle weight and carbon emission.
• - Resistant to acid, alkali and salt solution. Its performance remains stable below 80℃. It is widely used in chemical storage tanks, pickling tanks and waste gas treatment towers, with chemical stability comparable to PE.
• - Melting point 164~170℃, continuous service temperature 110~120℃, more than 20℃ higher than PE. Suitable for microwave food containers and steam-sterilizable medical devices.
• - Different grades can be produced by adjusting ethylene content and polymerization process: homopolymer PP with high rigidity for pipes; block copolymer PP with good toughness for bumpers; random copolymer PP with high transparency for food containers. Its performance is highly tunable via formulation.
• - Water absorption less than 0.01%, nearly non-hygroscopic. It maintains stable dimension in humid environment, and its electrical insulation performance is not affected by humidity, ideal for electronic housings and washing machine inner drums.
• - The price of general injection grade PP is about 8000~9500 CNY/ton, over 30% cheaper than ABS and over 60% cheaper than PC. The cost advantage supports its large-scale application.

5. Application Fields

6. Market Price

Data Period: April-August 2026 | Source: Ex-factory prices of major domestic PP resin manufacturers plus market quotations from East China and North China

7. Major Brands

8. Selection Guide

Identification Methods

1. Combustion test: PP burns with blue flame, releases paraffin odor, melts and drips, and continues burning after leaving fire.
2. Density test: PP density is 0.89~0.91. It floats in clean water and is the lightest among general-purpose plastics.
3. Marking check: Qualified PP products are printed with brand, specification, standard number (GB/T 12670) and production date.

Tips to Avoid Pitfalls

1. Beware of recycled or filled materials being disguised as virgin resin. Do not purchase pellets with grey color, impurities or pungent odor.
2. PP for food contact must comply with GB 4806.7 and be accompanied by third-party test reports.
3. Ordinary homopolymer PP cannot be used under low-temperature conditions due to insufficient impact strength. Copolymer PP or cold-resistant modified materials are required.

9. Storage, Transportation & Safety

1. Resin pellets shall be stored in cool and dry places away from direct sunlight, with storage period no more than 12 months.
2. Ambient temperature ≤40℃, relative humidity＜80%. Replace damaged packages promptly.
3. PP products shall be kept away from strong oxidants, halogenated compounds and aromatic hydrocarbons, as certain solvents may cause swelling.
4. Waste PP can be recycled and re-pelletized, marked with recycling code "05-PP".

10. Main Industry Standards