ASO Co., Ltd.

It is the most standard polyethylene and is referred to as a plastic bag.

It is clear, flexible, and has excellent tear strength and tensile strength and is widely used from food packaging to drums for inner bags.

2. Linear short-chain branched polyethylene (LLDPE)

This polyethylene is hard to discriminate from the above LDPE. Our expert operators also have difficulty in identifying them.

IR analysis or calorimetry (DSC) analysis is necessary to determine. However, the manufacturing process at the polyethylene resin stage is different from that at the high-pressure method low-density polyethylene (LDPE). As the polymerization process of ethylene is "ionic polymerization," we have determined that some elements are close to the medium-low-pressure method high-density polyethylene (HDPE). This is because it is designed to have many short molecular chains by copolymerising small amounts of C-4LL (butene-1), C-6LL (hexene-1) and C-8LL (octene-1) as comonomers depending on the type of hydrocarbon at the time of polymerisation, in order to take into account the properties of high pressure low density polyethylene (LDPE).Common LL are mostly of this type in C-4 LL. LLDPE has historically been a new polyethylene with better sealing performance and physical strength than LDPE.

 

3. Medium-low pressure high-density polyethylene (HDPE)

A typical application is a shopping bag at a supermarket. This bag is extremely thin, ranging from 15μm to 25μm. It is　made with opalescent (titania) colorant, but even if they do not contain colorant, they are stronger than LDPE, so they are used as ultra-thin films (10μm to 30μm). Also, when the thickness is 50μm or 100μm, it is used only for special applications because it is lack of flexibility or smoothly. Tensile strength is excellent when compared to LDPE, but it has a strong longitudinal (y-axis) direction and the tear strength is weak. When a cut is made on a film, you can tear up easily.

4. Metallocene-catalyzed linear short-chain branched polyethylene (LLDPE) 

This is a LLDPE that has recently emerged recently and is polymerized with a metallocene catalyst. It has a very sharp molecular weight distribution compared to the conventional catalyst (Ziegler-Natta catalyst) and a uniform distribution of co-monomers. Therefore, it is a polyethylene with excellent performance in tearing, pulling, sticking strength, and pinhole resistance properties. On the other hand, when we measured the tensile strength, the film was strong enough that the machine pulled to MAX without breaking. The fact that the mechanical strength is large means that it is possible to reduce the thickness (gauge down), so it can be said that it will be a material with low environmental impact in the future.

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