High-Density Polyethylene (HDPE) VS Low-Density Polyethylene (LDPE)

At The TOTI we use multiple kinds of plastic waste separately to create a host of our products. Since most of the waste we recycle is plastic bottle lids, the main types of plastic we process is HDPE (#2) and LDPE (#4). There are a couple of differences in the final product with each kind of plastic so we wanted to point those out to ensure you aren’t left wondering why a product may have a few visual variances from others.

Explaining LDPE

For the launch of our brand we only used LDPE plastic and that was because one of the key advantages of LDPE in injection moulding is its excellent flow properties. LDPE has a lower viscosity compared to other plastics, allowing it to flow more easily into intricate mould cavities and fill complex shapes with precision. This smooth and uniform flow of molten LDPE ensures that the material fully conforms to the contours of the mould, resulting in a smooth and seamless finish on the surface of the finished products. As much as we love using LDPE, our next launch is going to made solely using HDPE.

Introducing HDPE

Before purchasing one of our products made from HDPE it’s important to understand the distinct visual characteristic that sets HDPE items apart from their Low-Density Polyethylene (LDPE) counterparts. The main difference we’ve observed is a subtle rippling effect.

This rippling effect, while not present in LDPE items, is a unique attribute of HDPE that arises during the injection moulding process. It manifests as gentle undulations or waves on the surface of the finished product, creating a distinctive texture that adds depth and character to the item.

Several factors contribute to the development of this rippling effect in HDPE items. Firstly, the inherent properties of HDPE, including its high density and molecular structure, result in a slightly different flow behaviour during injection moulding compared to LDPE. As the molten HDPE material fills the mould cavity, it experiences subtle fluctuations and variations in flow, leading to the formation of the rippling pattern on the surface of the finished product.

Additionally, the design and dimensions of the injection mould play a crucial role in shaping the final appearance of the HDPE item. The size and style of the mould, as well as the intricacies of its geometry, can influence the distribution of material and the formation of surface features, such as the rippling effect.

While some may perceive the rippling effect as a minor imperfection, we view it as a distinctive hallmark of authenticity and craftsmanship. It serves as a testament to the unique characteristics of HDPE and the intricacies of the injection moulding process, adding a touch of visual interest and tactile appeal to each finished item.

In essence, the rippling effect observed on HDPE items produced through injection moulding is a fascinating interplay of material properties, manufacturing techniques, and design considerations. Rather than detracting from the quality of the product, it enhances its individuality and highlights the craftsmanship behind its creation.


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