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Polypropylene is a thermoplastic polymer that is a widely-used material for bulk bags. This petroleum-based compound was first discovered in 1951 by Phillips Petroleum as the result of experimental trials. The end result was a new type of plastic that can be used to create a highly versatile fabric for woven bulk bags

Polypropylene bulk bags are used across a wide range of industries for the transportation and storage of goods. These industries include, among others, chemical substances, agricultural products, construction materials and fast-moving consumer goods. Custom Bulk Bags is a leading manufacturer and supplier to all of these sectors in South Africa.

With an increasingly globalised world comes the need for fast and efficient storage solutions. Polypropylene bulk bags provide a safe, reliable and cost-effective method of transporting mass quantities of goods. The polymer has a number of properties that make the most appropriate choice of material for bulk bags. 

Polypropylene improves transportation and storage

Woven polypropylene bulk bags can be custom-made according to the needs of each client. This flexible material is used to create packaging of different shapes and sizes. Custom Bulk Bags can produce flexible containers from half a cubic metre up to two cubic metres in volume. These products are able to safely hold between 500 kilograms and two tonnes of produce.

Polypropylene bulk bags are breathable, which ensures that powdered products are not contaminated by moisture or mould. Good air circulation is essential for almost all products that require bulk packaging. Consider the effects of moisture build-up on water-soluble products, such as fertilizers and dry chemical powders. 

Apart from breathability, polypropylene has other logistical advantages. Namely, they are easy to fill, stack and empty. Warehouses can load bulk bags onto forklifts, easily packing them into shipping containers, or staking bags for storage purposes. Once emptied, the fabric containers can be folded away and stored in a small space.

It is preferable to store bags inside and out of direct sunlight, as polypropylene will degrade if left outside for a long time. Like other plastics, polypropylene is affected by UV exposure. Custom Bulk Bags can be ordered with a UV-inhibitor that allows the bag to withstand UV rays for up to 1600 hours. 

Safety and reliability are key considerations

Compared to other commercially available plastics, polypropylene is considered to be one of the safest. This makes it an excellent material for bulk bags. Polypropylene is inert and does not react to many chemicals or foods, which makes it ideal for the storage of these products. 

In addition, this polymer is BPA-free. Bisphenol A (BPA) is a chemical that is used to manufacture polycarbonate plastics, but it can easily leach into food or liquids. Although consuming small amounts if BPA is considered safe for humans, prolonged or excessive exposure can lead to a number of health issues, including immune disorders, brain development issues, reproductive disorders and learning abilities. 

Another safety aspect of polypropylene bulk bags is their safe working load (SWL). Bulk bags are tested for their strength and durability in order to determine their SWL. Custom Bulk Bags have a minimum safety factor of 5:1. This means that our products can hold at least five times more than their recommended maximum weight without breaking. 

Their strength and reliability mean that polypropylene bulk bags have a long shelf life. Most bags can be used for five years or more and can withstand a lot of tension without ripping or changing shape. Bags can hold their shape even after having been used a number of times, which is not only more cost-effective for the customer, but also better for the environment. 

Properties of polypropylene

Polypropylene is lightweight, yet incredibly strong. It is 20% lighter than nylon and 34% lighter than polyester, making it the most appropriate choice of material for bulk packaging. There are a number of other properties that give it a competitive advantage over other types of plastic. 

Compared to acrylic or polycarbonate, polypropylene is opaque in color. This means that light can’t easily enter the bag. Certain products, such as pigments or dyes used in the construction industry, are susceptible to light damage, so polypropylene is the ideal material for the external fabric.

Another key benefit is that it is resistant to pests and rodents, such as insects, moths and rats. It is also highly resistant to microorganisms, such as bacteria and mold. In addition, polypropylene is essentially rot-proof and mildew cannot develop on the surface of this material. These qualities make it extra durable and perfect for long-term storage.

Polypropylene also has anti-static properties, meaning that it does not generate static electricity as a result of friction when discharging materials from the bags. As such, polypropylene can be used to transport products that are sensitive to electrical currents, such as electronics, or flammable goods. There is a lower risk of fires starting due to static electricity and sparks. 

Keeping costs low

Polypropylene is cheap to produce and widely available. Currently, it is cheaper than competing plastics, such as polyester. By making bulk bags out of polypropylene, manufacturers can keep production costs low, in turn offering customers a more affordable product. 

Costs can be even further reduced by reusing bulk bags. Sensitive items, such as pharmaceuticals and food, may require virgin polypropylene to ensure that products are not contaminated during shipping or storage. However, most bulk bags can be reused multiple times with no problems. 

Choosing Custom Bulk Bags

Compared to other commercially available plastics, polypropylene is the most suitable choice for bulk bags, which is why Custom Bulk Bags opts for this material. Our products can be tailor-made to suit the needs of individual customers. 

Whether it is for food substances, agricultural products, or construction materials, Custom Bulk Bags are an excellent option for shipping and storage. For more information about our bulk bags, please contact us today. 


Custom Bulk Bags is a leading South African manufacturer of woven polypropylene bags for various industries, such as mining, chemicals and food. We are able to produce over 3.5-million bulk bags per year, keeping our customers in-stock at all times. Our bags adhere to the highest levels of quality as a result of our stringent in-house testing and quality control programmes.

Custom Bulk Bags holds ISO 9001 certification and we currently have a number of UN-certified designs. We are a Level 3 B-BBEE manufacturer and supplier and fall under the ownership structure of Deneb Investments Limited. For more information on our products, contact Follow us on Facebook for our latest news and industry insights.