LDPE

Low density polyethylene (LDPE) is a kind of high branched polyethylene. In the late 1940s, it was the first plastic to be commonly used commercially in packaging. LDPE is prepared by high pressure polymerization of ethylene. Unlike HDPE, it has a highly branched structure with long and short branches, which can interfere with crystallization. The lower crystallinity makes the density of LDPE lower than that of HDPE, and makes it softer and more flexible. As one of the most widely used commodity polymers, LDPE has been used in a variety of fields, including food packaging, general purpose containers, toys, bags and more.

Alfa Chemistry is committed to providing you with different specifications of LDPE to meet your scientific or industrial applications.  Contact us today to discuss your specific needs.

How to Make LDPE

LDPE is produced by a high-pressure radical polymerization process. In this process, ethylene gas obtained from petroleum or natural gas is introduced into the reactor along with a small amount of initiator (usually oxygen or organic peroxide) to initiate the polymerization. This process requires heat (420-570 °K) and high pressure (1000-3000 atm), so it is usually carried out in large batches in autoclaves or tubular reactors. LDPE granules can be further processed by extrusion, blow molding or injection techniques to produce a variety of products.

Performance Characteristics

The performance characteristics of LDPE include, but are not limited to the following.

• Flexibility and Toughness: LDPE has excellent flexibility and toughness and is able to withstand bending, stretching and impact without breaking or cracking.
• Chemical Resistance: LDPE is highly resistant to a wide range of chemicals including alcohols, acids and dilute alkalis.
• Processability: LDPE is highly processable and can be easily fabricated into films, sheets, fibers and molded parts through a variety of processing techniques such as extrusion, blow molding and injection molding.
• Electrical Insulation: LDPE has excellent dielectric properties and is an ideal choice for electrical insulation applications.
• Water Resistance: LDPE has low water absorption, so it has strong moisture resistance.
• Optical Transparency: Due to the crystallinity, HDPE is translucent in appearance. However, very thin foils can be transparent.

Applications

With its excellent performance, LDPE has brought revolutionary changes to all walks of life. The main applications of LDPE are as follows.

• Packaging: LDPE is widely used in food and non-food packaging such as packaging foils, trays and plastic bags. For example, one of the most famous applications is milk cartons, which form part of a system of different plastic layers.
• Agriculture: LDPE is widely used in agriculture for greenhouse films, mulch films, and irrigation pipes. Its resistance to UV radiation, flexibility, and excellent water retention properties contribute to improved crop yields.
• Medical: LDPE plays an important role in the medical field and can be used to make medical devices, prosthetics, medical hoses and pharmaceutical packaging.
• Consumer Goods: LDPE is used in the production of toys, bottles, containers and household products.

Our Products

Alfa Chemistry provides customers with LDPE in different material forms. The specific products are as follows:

LDPE Sheets & Rods

LDPE Films

LDPE Granules & Powders