A quad seal bag is a bag that looks square from the outside and square at the bottom. Although it is a soft package, it can still keep its shape after holding the product, making the whole package look three-dimensional and beautiful. The name of quad seal bag comes from its square bottom. It is like a carton with different length, width and height. However, its softness is different from that of a cardboard box. It needs to be customized according to different specifications and sizes of the packaged products.
High molecular polymer (or synthetic resin) is the main component of square bottom bag. In order to improve the performance of plastics, various auxiliary materials, such as fillers, plasticizers, lubricants, stabilizers, colorants, etc., should be added to the polymer to meet the requirements of plastics.
Generally, the quad seal bag is made of synthetic resin, and the bottom is named after the square. It unfolds like a carton, has different length, width and height, and is customized according to the different sizes of the products to be packed.
The quad seal bag generally has five sides, front and back, two sides and bottom. The unique structure of the quad seal bag determines the convenience of packaging three-dimensional goods or square products. This kind of bag not only considers the packaging significance of plastic bags, but also fully expands the new packaging concept, so it is now widely used in daily life and production.
There are two kinds of polymer structures in the quad seal bag.
1. Linear structure. Polymer compounds with this structure are called linear polymer compounds.
2. Somatotype structure, which is called somatotype polymer compound. Some polymers have branched chains, called branched polymers, which belong to linear structure. Although some polymers have cross-linking between molecules, they have less cross-linking, which is called network structure and belongs to bulk structure. Two different structures show two opposite properties.