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Bulk bags are made from woven polypropylene tapes, which creates an incredibly strong and durable fabric that can withstand a lot of wear and tear. However, being plastic-based, these tapes are affected by UV radiation from sunlight. This means that bulk bags left in direct sunlight for extended periods of time can become weaker.

UV light causes the plastic to degrade slowly, which poses a danger when the heavy bags are lifted or moved. To combat UV degradation, bulk bag manufacturers will spray the exterior with UV coating. This has no strength benefit but it does keep the polypropylene tapes intact and strong when the bags are left outside.

We always recommend that our customers store their bulk bags in a warehouse or under a shelter. If this is not a possibility, then cover the bags with a shade cloth or tarpaulin to protect them from UV rays.

Custom Bulk Bags is a leading manufacturer and supplier of bulk bags in South Africa. We produce up to 3.5 million bulk bags per annum, all of which have a minimum safety factor rating of 5:1 and are manufactured in accordance with international standards and regulations, including UN-certified designs.

Understanding UV rays and their effect on plastic-based fabric

UV radiation is the invisible energy produced by the sun. It is composed of three types of rays: UVA, UVB and UVC. UVA and UVB rays are the main types of radiation that reach the earth and both can damage plastic-based materials, including bulk bags. Prolonged exposure to UV rays causes the fabric to weaken, deteriorate and lose its strength, leading to expensive and avoidable bulk bag failures.

When UV rays interact with plastic, they create free radicals that erode the polymer chains in the plastic fabric on a molecular level. This erodes the fabric’s tensile strength, making the bag brittle and eventually leading to cracking or tearing.

How to prevent bulk bag leaks

How UV coating prevents degradation

UV coating is a protective layer of UV-resistant chemicals applied to the bulk bag fabric. The coating provides an extra layer of molecular protection and reflects UV radiation like a mirrored shield, preventing it from penetrating the fabric underneath. This technique helps preserve bulk bag integrity and extend its lifespan.

As a sunny continent, Africa experiences high levels of UV radiation. African companies operating in hot regions expose their bulk bags to high levels of direct sunlight, which increases UV degradation. Outdoor storage also increases the severity of the problem. 

Without proper preventive measures such as UV coating, African companies can experience premature bulk bag failures. UV coating is an affordable solution that can help businesses save money and increase the lifespan of their bulk bags.

Everything you need to design your own bulk bags

Custom Bulk Bags is your expert partner

At Custom Bulk Bags, one of our primary objectives is to help our customers navigate the bulk bag sector and make informed purchasing decisions. Our knowledgeable team offers expert guidance, industry knowledge and advice to help guide our customers towards the most suitable bulk bag solutions. 

Choosing Custom Bulk Bags as your supplier ensures that you get high-quality, durable bags that are UV resistant and can withstand the harsh African sun. We always recommend UV coating to customers who have outdoor storage spaces or who work in sunny conditions.

UV degradation can significantly impact the lifespan of bulk bags, leading to costly downtime, extra expenses and frustrated clients. UV coating can significantly reduce the effects of UV degradation and extend the shelf-life of your bulk bags

In conclusion, African businesses must consider using UV coating on their bulk bags to help protect them from the sun’s rays. Custom Bulk Bags is committed to delivering high-quality, UV-resistant bulk bags that stand up to the harshest of environments in Africa. 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 2 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, LinkedIn and Instagram for our latest news and industry insights.