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The choice of packaging material inevitably influences its cost, durability, effectiveness and lead times. This is true across all industries, including bulk bags. Modern bulk bags have been engineered thoroughly and stood the rigours of various tests to prove that they are a great solution for storing and transporting large quantities of material.

However, there are three types of bulk bags that have different properties as a result of their fabric. All are made from polypropylene (PP), which is a strong and durable polymer. Knowing which PP fabric to choose can make a massive difference to the value that you get out of your packaging products.

Custom Bulk Bags is a leading manufacturer and supplier of high-quality bulk bags in South Africa. We produce up to 3.5 million bulk bags per year for various customers. All of our bulk bags have a minimum safety factor rating of 5:1 and are manufactured in accordance with international regulations and standards.

Custom Bulk bags production floor

What are PP, OPP and BOPP?

PP is simply the acronym for polypropylene. This plastic has many beneficial properties that make it perfectly suited to packaging and protective coatings. It is often extruded into tapes and woven to create the fabric that is used to manufacture bulk bags. However, PP can be further manipulated.

Orientated polypropylene (OPP) is a type of plastic film that is stretched in one direction, hence the microscopic fibres are aligned. This helps with strength and creates a clear plastic film. OPP is commonly used to manufacture small plastic bags, clear labels and flip files.

Biaxially orientated polypropylene (BOPP) is a plastic that is stretched in two perpendicular directions. This further improves the strength of the plastic and is highly suited to printing, which is why BOPP is often used as a clear coating or laminate over woven PP tapes used for bulk bags. BOPP is ideal for brands that need intricate printing and details on their bulk bags, such as barcodes and small labels.

How demand for raw materials impacts the bulk bag industry

Pros and cons of each polymer


  • Recyclable, moisture-resistant, chemical-resistant, durable and versatile.
  • Not very resistant to heat or flames and has limited printability.


  • Durable, transparent, glossy, dust-resistant and moisture-resistant.
  • Difficult to stretch and are limited in their weight capacity.


  • High tensile strength, recyclable, high dimensional stability, transparency, low electrostatic charge, high printability and resistant to oils and water.
  • Low sealability. 
Manufacturing equipment used at Custom Bulk Bags

What is needed for your industry?

PP, OPP and BOPP are suited to specific applications. Your packaging company will be able to guide you towards the best product for your needs, but let’s cover some basics. PP bulk bags are your standard packaging product. They can also make good sandbags and geotextiles (or eco-bricks) due to their versatility, durability and cost-effective price point.

OPP is better suited to small packaging materials in the medical, pharmaceutical and food sectors. These packaging products don’t need to carry much weight, but they still need to be protective and durable. Think of sealable sandwich bags or packets for pills.

BOPP is best suited for heavier materials, such as dog food, charcoal or wood. However, when it comes to bulk bags, BOPP can be used as a laminate over the PP fabric to improve the durability of the packaging and the precision of printing.

Custom Bulk Bags manufactures an array of bulk bags that are suited to your needs. These are all based on PP fabric that is extruded and woven in-house. We offer several optional extras, including printing and customisation. 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 for our latest news and industry insights.