Composite bag

Paper-plastic composite bags are made by laminating plastic with kraft paper. The plastic layer typically consists of a flat‑woven fabric based on polypropylene (PP) or polyethylene (PE), while the kraft paper is a high‑grade, specially formulated composite kraft paper. These bags offer high strength, excellent water resistance, and an attractive appearance. They are among the most popular packaging materials today and are widely used in industries such as plastics, cement, animal feed, chemicals, and fertilizers.

Paper-plastic composite bags—also known as composite plastic woven bags—are manufactured by laminating a plastic woven fabric (commonly referred to as “fabric”) with other layers using the cast‑film lamination process. These bags can be configured as either two‑layer composites (fabric/film) or three‑layer composites (fabric/film/paper). They are primarily used for packaging powdered or granular solid materials, such as engineering plastics, rubber raw materials, construction materials, food products, fertilizers, and cement, as well as flexible items.

● Composite woven bags: Classified by primary material into polypropylene two‑in‑one bags, polypropylene three‑in‑one bags, polyethylene two‑in‑one bags, and polyethylene three‑in‑one bags; classified by sealing method into bottom‑seamed bags, heat‑sealed bags, outer‑valve bags, and inner‑valve bags.

● Classified by effective bag width into 450, 500, 550, 600, 650, and 700 mm; any bag with an effective width that does not conform to the above specifications.

Paper-plastic composite bag: commonly known as a “three-in-one bag”

(1) Definition and Explanation

Paper-plastic composite bags—also known as three‑in‑one composite paper bags—are small bulk containers primarily used for unitized handling by hand or forklift. They are well suited for transporting small quantities of loose powdered or granular materials and offer high strength, excellent water resistance, an attractive appearance, and ease of loading and unloading. As such, they have become one of the most popular and practical packaging solutions today.

(2) Process description: The exterior is made of refined white kraft paper or yellow kraft paper, while the interior uses plastic woven fabric. Under high temperature and pressure, the polypropylene (PP) particles melt, bonding the kraft paper and the plastic woven fabric together. An inner liner bag can be added separately. This paper–plastic composite bag is equivalent to a sewn‑bottom open‑mouth bag and offers excellent strength, as well as superior water‑proof and moisture‑resistant properties.