Polyethylene Resin

1. What are the characteristics of the chemical structure of polyethylene PE?

Polyethylene has the chemical formula (C2H4)N. Essentially, it is a long-chain polymer formed by the polymerization of a large number of ethylene monomers. ‘N’ represents the degree of polymerization. Different degrees of polymerization affect the molecular weight and properties of PE. Its molecular chain structure is divided into two main types, linear structure (HDPE, LLDPE) and branched structure (LDPE). The regularity of the molecular chain, the number of branches, and their length directly determine the key properties of PE, such as density, hardness, and toughness.

2. What are the core differences between PE and PP/PVC?

Compared to PP: PE has better low-temperature resistance and toughness, but slightly worse heat resistance. PE is softer, while PP is harder and more brittle.

Compared to PVC: PE is non-toxic and odorless, and can be used in food contact applications. PVC contains chlorine, and toxic substances may be generated during production and recycling. It also requires the addition of plasticizers and is generally not used for food packaging. PE has stronger chemical stability and is resistant to acid and alkali corrosion, while PVC is easily corroded by strong oxidizing agents.

3. What are the differences between the three common types of polyethylene (HDPE, LDPE, LLDPE)?

Low-density polyethylene (LDPE): The molecular chain has a branched structure, with a density of 0.910~0.925 g/cm³. It is the softest, has good transparency, and is highly tough. It is mainly used for plastic films, food packaging, and agricultural greenhouse films.

High-density polyethylene (HDPE): The molecular chain has a linear structure, with a density of 0.941~0.965 g/cm³. It has superior hardness, heat resistance, oil resistance, and resistance to environmental stress cracking. It is mainly used for hollow containers, pipes, and woven bags.

Linear low-density polyethylene (LLDPE): The molecular chain has a linear structure, with a density between LDPE and HDPE (0.915~0.925 g/cm³). It combines the toughness of LDPE with the strength of HDPE. It has a good surface gloss and strong puncture resistance. It is mainly used for agricultural films, packaging films, and cable materials.

4. How are the heat resistance and low-temperature resistance of PE resin?

• Heat Resistance: Overall heat resistance is moderate, with a continuous operating temperature of 80~110℃. PE has good thermal stability in inert gases, with a decomposition temperature exceeding 300℃. However, when heated above 50℃, thermal oxygen can trigger degradation, requiring the addition of antioxidants.
• Low Temperature Resistance: PE is one of the plastics with the best low-temperature resistance, with a brittle temperature generally below -50℃ and a minimum tolerance of -140℃. It maintains good toughness and is not prone to cracking in low-temperature environments, making it suitable for use in cold environments.

5. Why the Barrier Property of PE plastic is So Important?

In most applications plastic containers for hollow goods, barrier properties are often very important. Among the barrier properties to various substances, the permeability to oxygen, carbon dioxide, nitrogen, organic solvents, and the permeability to water and water vapor are particularly important in practical applications. They can directly affect the protective effect of plastic containers on the packaged items.

6. What are the processing methods for polyethylene?

Extrusion molding (for pipes, films, cable materials).

Injection molding (for daily necessities, turnover boxes).

Blow molding (for hollow containers, such as plastic bottles).

Rotational molding (for large storage tanks).

7. Can polyethylene be used in food contact applications?

Virgin polyethylene itself is non-toxic, tasteless, and odorless, contains no harmful substances, and meets food contact safety standards. It is one of the most commonly used plastic materials in food packaging. However, PE resin used for food contact must be food-grade, and no harmful additives must be added during the production process.

8. Can polyethylene products be recycled?

PE is a recyclable plastic. After recycling, it can be processed into new PE products (such as plastic pipes, trash cans, recycled plastic films, etc.). The recycling rate of HDPE is approximately 76%, while industrial packaging films and agricultural films with a thickness ≥0.01 mm have higher recycling rates for LDPE.

9. What is the Shelf Life of Polyethylene PE Resin?

Polyethylene resin should have a storage period, generally no more than 12 months from the dat of production.

The PE resin beyond the shelf life has reached the lower limit in terms of various values. But even so, as long as its various values are still within the standard range of the storage period, it can continue to be used. In order to prolong its shelf life, please store the resin away from heat sources. This can reduce the rate of free radical curing initiation and reduce the consumption of inhibitors.

10. What factors affect the price of polyethyleneresin?

Raw material costs: Ethylene monomer prices are significantly affected by international crude oil prices.

Production process, product grade, market supply and demand, and the cost of additives (antioxidants, light stabilizers, etc.).

11. Which brands of polyethylene does our company export?

Our company specializes in polyethylene exports, supplying brands including internationally renowned names and high-quality Chinese brands to meet the needs of diverse customers. Internationally renowned brands include SABIC, Lotrene, Dow, ExxonMobil, Marlex, PTT, LyondellBasell, etc., as well as all specifications and models from all production companies under Sinopec and PetroChina. All brands are genuine original products, and brand authorization and product qualification certificates can be provided.

12. What types of PE resindoes your company export?

Our company exports PE resin covering three core types: LDPE, HDPE, and LLDPE, including injection molding grade, extrusion grade, blow molding grade, and film grade, among other processing levels. These can be widely used in food packaging, building materials and pipes, industrial parts, agricultural films, and other applications. Whether it’s general-purpose products or high-end customized products, we can supply them according to your needs.