Manufacturing Process of PP Woven Bags

PP woven bags, also known as polypropylene woven bags, are a flexible and durable packaging solution widely used in many different industries. The manufacturing process for these bags involves several complex steps to turn raw polypropylene plastic into sturdy, lightweight and cost-effective woven bags. Understanding the complexities of this manufacturing process is critical for businesses looking to optimise production efficiency, ensure quality control and meet the growing demand for packaging solutions. Environmentally friendly package. In this comprehensive guide, we will delve into the intricate details of the PP woven bag manufacturing process, exploring each stage from raw material preparation to the final product.

We are happy to provide a variety of options that are best suited for their intended use. PP woven bags and coated bags are ideal for packaging products with a risk of leakage, from fine particles such as sugar or flour to more hazardous materials such as fertilisers or chemicals. Protective films help protect product integrity by preventing contamination from external sources and reducing moisture or absorption. 

Let’s join us to find out the process of producing PP plastic bags and how our products meet the requirements of users and industries today.

How we make PP woven bags

Stage 1: Choosing and collecting PP raw materials

In the first step, we choose 100% polypropylene plastic particle composition for the best quality.

In addition, to ensure optimal use of PP bags and ensure product quality, our factory will add other additives such as:

• Anti slip and anti slip: Make PP bags easy to move on the surface and prevent them from sticking together.
• Anti fog agent: prevents water vapour from condensing on the surface of the packaging, helping to better preserve internal products.
• Coloured powder: Create colours for PP bags based on aesthetic needs or product differentiation.

Stage 2: Pulling into PP line

After selecting raw materials for production, we melt plastic granules and additives to create large PP sheets, then the PP sheets are processed through cutting machines to create PP lines.

During the extrusion process, PP pellets are typically heated to temperatures above the melting point of PP, which is typically around 180-220°C (356-428°F). The temperature is maintained continuously so that there are no errors in the production line and the PP plastic fabric is continuously cut to form plastic rolls.

If this process is not stable, the PP plastic fibres used to weave PP bags will be brittle and easily damaged. If not heated enough, the finished product will lose its durability and reduce the tension of the PP bag.

Stage 3: Coarse textiles (Weaving)

After the PP plastic roller is formed, the plastic roller is fed into a weaving machine to sew into a PP fabric tube.

According to the different machines, the opening size of PP fabric pipes can output many opening sizes. Then, the PP fabric woven into pipes will be rolled into each roll to prepare for the next stage

Stage 4: PE/BOPP laminated coating

The woven PP fabric can be further processed through the following steps:

• Rolling: to make the surface of the fabric smooth.
• Coating: Add a layer of film to increase waterproofing, UV resistance, or pattern.
• Lamination: Splicing multiple layers of fabric together to increase thickness and durability.

Depending on the customer’s demand, this step is done to coat the outside of the PP bag or the inner lining of the PP bag.

Stage 5: Printing

Design:

• The first stage is to design PP bag samples according to customer requirements.
• The factors that need to be considered in design include size, design, color, logo, product information, etc.
• Use specialised design software such as Adobe Illustrator, CorelDRAW, etc.
• Ensure that the design complies with the printing technology used.

Printing mould installation:

• Install the printing mould in the correct position on the printer.
• The mould should be thoroughly inspected to ensure there are no defects or damage.

Printing:

• Start the printing process.
• The printing speed depends on the type of printer, PP bag material, and design complexity.
• It is necessary to monitor the printing process to ensure satisfactory quality of printed images.

Drying:

• After printing, the PP bag is dried through an automatic or manual drying system.
• Its purpose is to remove solvents from the ink and help print images better adhere to the PP bag.

Quality inspection:

• The finished PP bag has undergone quality inspection to ensure no printing errors, clear images, and accurate colours.
• Defective products will be removed.

Stage 6: Cutting and shape sewing

After printing and inspecting the package, it will enter the cutting and moulding stage of PP package. According to the customer’s requirements, the factory can cut packages of different sizes according to the SPEC sent by the customer with 3 steps as follows:

Prepare:

• PP bag: It should be ensured that the PP bag has been printed and completed as required.
• Thermal cutting machine: The thermal cutting machine should be inspected and ensured to work properly.
• Cutting mould: The cutting mould should be selected based on the size and design of the PP bag.
• Candle paper: When cutting, candle paper is used as a lining under the PP bag to help protect the packaging surface and avoid adhesive adhesion.

Cutting PP bags:

• Place the PP bag on the candle and secure it in place.
• Place the cutting mould on the PP bag to ensure an accurate cutting position.
• Put down the hot cutting knife and move along the cutting mould.
• Apply appropriate temperature and pressure to cut PP bags.
• Pick up the hot cutting knife and take out the cutting mould.

Complete:

• Remove the PP bag from the candle.
• Check the quality of the cutting line to ensure there are no defects or defects.
• Cut off excess candle paper.
• The finished PP bag can be used or packaged according to requirements.

Stage 7: Packing

After the finished PP packaging is produced, we will have to roll it and put it in bales for storage and transportation to customers.

What makes our PP Bags special? 

Choosing our products grants you various advantages:

• Tailoring PP woven bags according to your specific needs (type, size, colour, material, printing, etc.). We can design bags with 65gsm (very thin) while most other suppliers can only make a minimum of 70gsm.
• Professional and separate production process, ensuring the best product quality (Weaving machines, cutting machines, printing machines, fibre pulling machines,… all are the most modern models)
• Providing the best price on the market (Cheaper than other competitors by 10-15% because we are direct manufacturers)
• The purchasing process is easy, quick and precise

At present, we have teamed up with various shipping firms, all of which are well-established and reliable, including: J&T Express, DHL, FedEx, UPS, Yusen Logistics, Hapag – Lloyd,… We are confident that the goods will be delivered to you as soon as possible.

The manufacturing process of PP woven bags proves the originality and accuracy of these environmentally friendly and multi-purpose packaging solutions. From the initial stage of raw material preparation to complex textile, lamination, and finishing processes, each step plays an important role in determining the durability, durability, and aesthetics of the final product. The above is the manufacturing process of PP woven bags. We hope this article can help you better understand the manufacturing process of PP woven bags, or help new manufacturers gain more knowledge to improve product quality.