Multiwall Paper Square Bottom Bags

Multiwall paper square bottom bags are robust, versatile packaging solutions that provide unmatched strength and stability. Crafted from premium, multi-layered paper, these bags are specifically designed to handle a wide range of applications. From food products to chemicals and charcoal, they offer a safe and reliable method for transporting and storing bulk materials. With a variety of customization options available, these bags can be tailored to meet your specific packaging needs, making them a perfect choice for businesses looking to enhance their product presentation and improve operational efficiency.

 

 

Our Multiwall Paper Square Bottom Bags are a sustainable packaging solution that combines durability with eco-friendliness. Made from multiple layers of high-quality kraft paper, these bags are engineered for maximum strength and long-lasting performance. The square bottom design not only ensures the bags stand upright for easy filling and stacking but also provides superior strength, capable of withstanding loads up to 50 pounds. This makes them perfect for packaging and transporting bulk materials such as fertilizers, grains, animal feed, chemicals, and other heavy products.

 

 

 

Exceptional Strength and Durability:

Multiwall Paper Square Bottom Bags are built to endure heavy-duty applications. Constructed with three or more layers of premium kraft paper, these bags offer exceptional tear resistance and the ability to carry up to 3-5 times their own weight. This makes them ideal for holding bulk goods like fertilizers, food ingredients, or construction materials. The multi-layered structure efficiently disperses external pressure, enhancing the bags' durability and tear strength by 20-30%, making them resistant to the physical stresses encountered during transport and handling.

Moisture Resistance:

One of the standout features of Multiwall Paper Square Bottom Bags is their moisture resistance. A layer of polyethylene (PE) film is added to provide a waterproof barrier, preventing water from seeping into the bag. This layer protects the contents from moisture damage, which is particularly important for products like fertilizers, food, and chemicals. The moisture-resistant properties can extend the shelf life of stored goods by up to 30%, reducing spoilage, waste, and improving supply chain efficiency.

Customization Options for Your Needs:

Our Multiwall Paper Square Bottom Bags can be fully customized to suit your specific packaging requirements. Available in a wide range of sizes and shapes, you can select the perfect fit for your products. In addition, customization options include easy-open features, reinforced handles for added convenience, and the option to print up to eight colors. This allows businesses to create unique, branded packaging that not only protects their products but also increases brand visibility and recognition on retail shelves.

Space Efficiency and Easy Storage:

The square bottom design of these bags offers significant space efficiency. When filled, they stand upright, which makes them easier to fill, stack, and store. This design maximizes storage space and ensures that your products are securely packed. Additionally, when empty, these bags can be flattened and folded, saving valuable space during transportation and reducing shipping costs. This space-saving feature makes them ideal for businesses looking to optimize their supply chain operations and reduce overall packaging costs.

 

Product name	Multiwall Paper Square Bottom Bags
Paper Material	Paper( Kraft paper/bleached white paper)
Features Selection	Biodegradable/ recyclable/eco-friendly/Waterproof/moisture proof/leak proof
Paper Color	Brown/ white/ customized color
Paper GSM	40-150gsm customized
Paper Layers	1/2/3/4/5/6 layers
Bag Width	30-70cm customized
Bag Length	40-120cm customized
Capacity	2kg, 5kg, 10kg, 20kg, 25kg,50kg or customized
BagTop	Cold cut/ zigzag cut/D cut/hemmed top/handle pasted
Bag Bottom Seal	Single line sewing/ double lines sewing/ easy open/heat seal tape/ block bottom/ valve
Coating option	PE film/9-40 gsm/( inside/outside)
Lamination option	PP woven fabric
Printing	Offset printing Max 5 colors /Flexo printing Max 10 colors
Bag Shape	Tubular/ M gussets/ Block bottom/Valves
Optional Processing	PE liner inside/ anti slip/Micro perforation/ventilation holes
Usage	Flour,feed, fertilizer,chemical, resin, powder products,charcoal
Packaging	In bales/ Palletization with cardboard
MOQ	2000 pics
Production Capacity	300 tons/ month
Loading Port	Qingdao
Delivery Time	15-40 days
Certification	FSSC22000/ISO22000/ISO9001/BRC/SGS
Payment	TT/LC
Samples	Free samples available

 

 

The production process of multiwall paper bags primarily involves material lamination, tubular forming, square bottom shaping, and bag opening treatment. The square bottom is formed by folding and gluing the cylinder's bottom into a square shape, followed by reinforcement to ensure the bag's ability to handle heavy loads. Throughout the entire process, precision control is essential to produce durable, high-quality paper bags that meet all performance standards.

1. Raw Material Selection:

The production of Multiwall Paper Square Bottom Bags begins with the meticulous selection of raw materials. High-quality kraft paper is the primary material chosen for its exceptional tensile strength, tear resistance, and ability to support heavy loads. The paper's GSM (grams per square meter) is carefully selected to ensure optimal durability, with common options ranging from 60 GSM to 120 GSM, depending on the specific requirements of the bag. The construction typically involves multiple layers of kraft paper, which may include a layer of polyethylene (PE) film for added moisture resistance.

Multiwall paper bags are typically made from several layers of paper. The outer layer is robust kraft paper, while the middle layer consists of recycled paper or standard paper. These materials are first rolled into large rolls, preparing them for the production line.

These raw materials are sourced from certified suppliers who adhere to stringent standards, ensuring that the paper not only provides superior performance but is also environmentally sustainable. This careful selection and layering process guarantees that the bags are both strong and eco-friendly, meeting the demands of modern packaging needs.

2. Printing

If the bag requires printing of logos, brand names, product information, or regulatory markings, the paper undergoes a printing process before it is converted into paper bags. In this stage, large rolls of kraft paper or bleached white paper are fed into a high-speed flexographic (Flexo) printing machine, which uses flexible relief plates to transfer ink onto the paper surface. This type of printing is especially suitable for packaging materials, as it accommodates a wide range of inks and dries quickly, ensuring high-quality, smudge-free results.

Flexographic printing, often referred to as Flexo, is a modern high-speed printing method widely used in the packaging industry, especially for materials like kraft paper, plastic films, foil, and other substrates that are not ideally suited for traditional offset printing. Its versatility, efficiency, and ability to produce sharp, colorful images make it the go-to choice for printing on multiwall paper bags.

 

 

 

1). Unwinding the Paper Roll

• Large rolls of kraft paper are fed into the Flexo machine.
• The unwinder ensures smooth and continuous feeding of the substrate.

2). Ink Fountain & Rollers

• Ink is held in the ink fountain.
• A fountain roller picks up the ink and transfers it to the anilox roller.
• The anilox roller, covered with tiny engraved cells, meters the right amount of ink and transfers it to the plate cylinder.

3). Plate Cylinder

• A flexible photopolymer plate wraps around the plate cylinder.
• The raised areas on the plate carry ink and print the image onto the paper.

4). Impression Cylinder

• The paper passes between the plate cylinder and impression cylinder.
• The impression cylinder presses the paper against the plate, transferring the inked image.

5). Drying Unit

• After each print station, the paper passes through a hot air or infrared dryer.
• This ensures the ink is dried before moving to the next color station.

6). Additional Color Stations

• The same process is repeated for each color in the design.
• Machines can have 2 to Max 8 color stations, depending on complexity.

7). Rewinding

• Once printing is complete, the paper is rewound into a roll.
• It is now ready for bag conversion (tubing, bottoming, etc.).

 

This step is crucial for ensuring brand visibility, regulatory compliance, and product differentiation in the market. Whether for agricultural products, food items, or industrial materials, clear and accurate printing enhances the professional appearance of the final bag and contributes to a more appealing and trustworthy product presentation.

 

 

The production process begins as the printed outer kraft paper and the selected inner layers-whether recycled, bleached, or virgin kraft-are unwound from large rolls and simultaneously fed into the bag-making machine. These layers are precisely aligned to ensure uniform thickness and strength throughout the bag.

Inside the forming unit, the papers are shaped into a continuous cylindrical tube. The longitudinal side seam is bonded using high-strength industrial adhesive through a back-seam gluing method, which ensures a seamless appearance and structural integrity. This step forms the core body of the bag.

If the bag design includes gussets-folds on the sides that expand to increase capacity and stability-these are also formed at this stage using precision-guided folding mechanisms.

Once the continuous paper tube is complete, it passes through a cutting station where it is sliced into individual units based on the customized bag length. This step is digitally controlled to guarantee consistency across large production batches.

The process is engineered for flexibility, allowing manufacturers to adjust parameters such as width, length, gusset depth, and layer count to meet specific customer requirements. This stage sets the foundation for the subsequent square bottom forming and mouth finishing steps, where the bag gains its final three-dimensional shape and usability features.,

 

 

The square bottom is a critical part of the multiwall paper bag, as it must bear heavy loads. The steps for processing the square bottom are as follows:

1. Flattening the Bottom

The round bottom of the cylinder is flattened to create a smooth, level surface.

2. Folding into Shape

The bottom is folded in a "cross" pattern to create four triangular corners. Precision is key during this step to ensure each corner is folded at a perfect 90-degree angle.

3. Adhesive Bonding

The folded sections are glued together with a strong adhesive to ensure a secure bond. Sometimes, reinforcement strips are added at the four corners for extra strength.

4. Heat Pressing and Shaping

Once the adhesive is applied, the bottom is pressed with a heat press machine to ensure the glue is evenly spread, and the bottom remains smooth and bubble-free.

Adhesive application plays a crucial role in bonding these layers together. A strong adhesive ensures the layers stay intact and work as one cohesive unit, enhancing the bag's overall strength and durability.

 

 

The final stage in the production process is the treatment of the bag opening, tailored according to the specific application and filling method required by the end user.

For open-mouth bags, the top of the bag is intentionally left open and neatly trimmed during production. This design allows for manual or semi-automatic filling, commonly used for products like grains, pet food, powdered chemicals, or cement. After filling, these bags can be sealed using various closure methods such as sewing, heat sealing, or adhesive taping, depending on the contents and industry standards.

 

 

Alternatively, for valve-type bags, a valve sleeve-usually constructed from reinforced paper or sometimes combined with a PE liner-is affixed to the top corner of the bag. This self-closing valve design enables efficient, dust-free filling using automatic filling machines. The valve allows the product to enter the bag while preventing backflow and spillage, making it ideal for high-speed filling lines and powdered or granular materials. Some advanced valve designs may also include a film liner or flap for additional sealing and product protection.

 

 

Regardless of the opening style, each bag undergoes a precision-cutting process to ensure clean edges, uniform dimensions, and seamless integration with downstream filling equipment. This ensures that the bags are not only functionally efficient but also aesthetically consistent for retail or industrial presentation.

 

 

For applications requiring moisture resistance, a layer of polyethylene film is added to the bag. This film is carefully laminated or coated onto the paper layers to provide a waterproof barrier. This crucial step ensures the bag can resist external moisture and keep its contents protected from damp environments, which is particularly important when packaging items like fertilizers, chemicals, or food products.

The addition of PE film also helps prolong the shelf life of the contents by preventing water penetration that could lead to spoilage or degradation.

 

 

Quality control is a crucial aspect of the production process. Every batch of Multiwall Paper Square Bottom Bags undergoes rigorous testing to ensure that they meet industry standards for strength, durability, and functionality. These tests include:

• Tensile strength testing: Ensuring the bags can withstand the weight and pressure they will encounter during transportation and storage.
• Moisture resistance testing: Confirming that the bags maintain their integrity and perform as expected under humid or wet conditions.
• Seam strength and seal ability testing: Verifying that the seams and seals of the bag are secure and that the bags can be effectively closed without leakage.

 

 

Once the multi layers paper bags have passed quality control, they are packaged and prepared for shipment. The bags are stacked in a way that optimizes space for storage and transportation. They are then shipped to clients worldwide, ready to be filled with a wide range of products.

Throughout this process, care is taken to minimize waste and ensure the sustainability of the production method. By choosing environmentally friendly materials and optimizing production techniques, the entire process aligns with sustainable packaging practices.

The production of Multiwall Paper Square Bottom Bags combines advanced technology with sustainable materials, resulting in a product that is both reliable and eco-friendly. This multi-step process guarantees the final bags are strong, durable, and capable of meeting the diverse needs of industries ranging from agriculture and food packaging to chemicals and construction materials.

 

 

Due to their strength, durability, and versatility, Multi layers Paper Bags are ideal for a wide variety of industries. Some of the most common applications include:

• Agricultural Packaging: Perfect for bulk products such as fertilizers, seeds, grains, and animal feed.
• Food Packaging: Suitable for dry goods such as flour, sugar, and rice, these bags offer safe and moisture-resistant storage for food products.
• Chemical Packaging: The multi-layered construction and moisture resistance make these bags ideal for packaging chemicals, including powders and granules.
• Construction and Building Materials: Multiwall paper bags are strong enough to store and transport heavy materials like cement, sand, and other building supplies.

 

 

• Eco-Friendly: Made from sustainable kraft paper, these bags are biodegradable and recyclable, offering an environmentally friendly alternative to plastic packaging.
• High-Performance: The robust construction ensures that the bags can withstand even the harshest conditions during transit, making them reliable for both long-term storage and shipping.
• Cost-Efficient: Despite the slightly higher initial investment compared to single-layer paper or plastic bags, the long-term durability, moisture resistance, and customization options make Multiwall Paper Square Bottom Bags a cost-effective packaging choice.
• Versatile Customization: From size adjustments to branding options, these bags can be tailored to perfectly match your business's packaging needs.

Multiwall Paper Square Bottom Bags provide a reliable, sustainable, and customizable packaging solution for a wide variety of industries. Their strong, multi-layered construction ensures they can withstand heavy loads and harsh conditions, while their moisture resistance extends the shelf life of contents, reducing waste and improving supply chain efficiency. With customizable features such as size, shape, and print options, these bags offer businesses the opportunity to enhance brand visibility and streamline their packaging processes.

Whether you're in the agricultural, food, or chemical industry, Multiwall Paper Square Bottom Bags are the ideal packaging solution to protect and transport your products efficiently and securely.

 

 

 

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