Valve bags are a type of packaging designed with the goal of improving packaging efficiency and ease of transport. Below is a brief explanation of the adaptability of valve bags.
1. Definition of Valve Bags:
Valve bags, commonly known as "pasted bottom bags," are small bulk packaging containers that are convenient, neat, and have good sealing properties. They are one of the most popular packaging materials today, especially suitable for export packaging. The overall appearance of the bag is square, making it ideal for stacking and transportation. The valve at the bottom allows for easy filling of materials, and the closure process is simple and straightforward. This type of bag is suitable for new environmentally friendly packaging with filling equipment.
2. Valve Bag Manufacturing Process:
Valve bags are made from paper-plastic composite bags or kraft paper bags. Their size and specifications are based on customer requirements. Using environmentally friendly glue, the bags are hand-folded and sealed at both ends, or sealed at the bottom with an open top. These bags can be divided into paper-plastic composite valve bags or multi-layer paper valve bags. For ease of filling, holes can be punched in the bag to allow air to escape and prevent bursting during the filling process. A layer of plastic film can be added in the middle of the paper to package moisture-sensitive products.
3. Materials Used for Making Valve Bags:
1. Paper-Plastic Composite Valve Bags: These bags use woven plastic bags (referred to as base fabric) as the base material, which are laminated using the casting method. The composite structure (fabric/film/paper) forms a three-in-one bag.
2. Kraft Paper Valve Bags: These are made from kraft paper, which comes in either imported or domestic varieties. The number of layers of kraft paper typically ranges from one to six, depending on the application. A plastic film or PE plastic membrane can be applied between the layers.
3. PE Valve Bags: Commonly referred to as heavy-duty valve bags, these are made from polyethylene film, with a typical thickness ranging from 8 to 20 microns.
4. Low Melting Point Valve Bags: Made from low-melting-point polyethylene film, these bags also have a thickness of 8 to 20 microns. They are well-suited for large-scale production in chemical enterprises on assembly lines, helping to reduce pollution and lower worker labor intensity.
4. Printing Details for Valve Bags:
Valve bag printing generally ranges from one to four colors, with a maximum of eight colors possible.
5. Advantages and Applications of Valve Bags:
Advantages - Composite valve bags combine the printability of paper with the moisture resistance and durability of plastic, making them a new type of material. They feature increased packaging efficiency, ease of transport, strong durability, and a low damage rate.
Applications - Valve bags are widely used for packaging powdered and granular products such as chemical raw materials, new building materials, high-tech materials, pharmaceutical additives, food additives, starch, dairy products, engineering plastics, leaf paper bags, and pet food bags.
Difference Between Open-Mouth Bags and Valve Bags:
Both open-mouth bags and valve bags are popular packaging solutions frequently encountered in everyday life.
Open-Mouth Bags: These are cylindrical bags that are sealed at the bottom but open at the top. Products are filled into the bag by either pouring or under the force of gravity, and the bag is sealed using an industrial sewing machine. Shopping bags, convenience bags, and woven bags are examples of open-mouth bags.
Valve Bags: As the name suggests, valve bags have a "valve." Both ends of the bag are sealed, with a small valve left for filling through machinery. Products are filled into the bag using pneumatic or mechanical force through this valve.
Valve bags can be categorized into external and internal valve bags. The sealing mechanism works by the internal contents pressing against the valve to close it after filling. External valve bags require manual folding after filling, while internal valve bags self-seal automatically once the material is filled.
The difference in manufacturing processes also affects their application. Valve bags have a higher packaging cost and require more expensive machinery, but they offer precise measurements, are easy to stack, and save significant labor costs due to their self-sealing feature. Additionally, valve bags provide a more aesthetically pleasing appearance, enhancing product image.
