What are the classifications of paper-plastic composite bags, and why is product cleanliness important?

Paper-plastic composite bags are made from plastic and kraft paper, typically using a polypropylene (PP) plastic layer or a polyethylene (PE)-based flat-woven fabric, combined with refined composite kraft paper. They offer high strength, excellent water resistance, and an attractive appearance. As one of the most popular packaging materials, they are widely used in industries such as plastics, cement, animal feed, chemicals, and fertilizers. Common product types include coated-paper bags and paper-plastic polypropylene woven bags. The following section introduces the classification of paper-plastic composite bags and the importance of product cleanliness:

I. Classification of Paper-Plastic Composite Bags

1. Polyethylene (PE): Polyethylene is one of the highest-volume synthetic resins produced worldwide and also one of the most widely used plastic packaging materials. However, traditional PE-based plastic packaging is being phased out due to its significant environmental impact. Polyethylene products are classified into low-density, medium-density, and high-density grades. Among these, high-density polyethylene (HDPE) features high crystallinity, excellent rigidity, gas barrier properties, mechanical strength, and chemical resistance. In contrast, low-density polyethylene produced under high-pressure conditions contains a higher proportion of low-molecular-weight polyethylene, which is more readily soluble in oils. Consequently, if packaging made from polyethylene is used for extended periods to contain edible oils, the low-molecular-weight polyethylene can leach into the oil, imparting an off-flavor to oil-rich foods.

2. Polyvinyl chloride (PVC): PVC can be broadly classified into rigid, flexible, and paste-like grades. PVC bottles produced by injection molding, stretching, and blow molding are seam-free and feature uniform wall thickness.

3. Polypropylene (PP): Due to its high transparency, smooth surface, and excellent processability, it can be compounded with other materials to produce a wide range of beverage packaging containers.

4. Polyester (PET or PETP): PET bottles produced by biaxial stretch blow molding exhibit excellent transparency, high surface gloss, and a glass-like appearance. PET is a commonly used resin in everyday life. Thermoplastic polyesters possess outstanding toughness, tensile strength, impact resistance, wear resistance, and electrical insulation properties. Owing to their superior toughness, light weight, impermeability, and resistance to acids and alkalis, they have increasingly become the material of choice for carbonated beverages, fruit juices, soft drinks, and other similar products in recent years.

II. The Importance of Cleaning Paper-Plastic Composite Bags

Cleaning the ink from paper-plastic composite bags can be very troublesome. If you want to clean it quickly and easily, you need to choose an effective cleaning method. Proper cleaning will make the bag look better.

1. Environmental protection has become integral to people’s work and daily life in today’s society. Therefore, when selecting an ink cleaner for paper-plastic composite bags, environmental considerations must not be overlooked.

2. Waste liquids generated from used cleaning agents shall be collected and treated centrally, and discharged only after sedimentation. The ultimate goal of production is to achieve sound corporate performance, and this holds true for the paper-plastic composite bag manufacturing industry as well.

3. The cost and effectiveness of ink cleaning agents are of great importance to paper-plastic bag manufacturers. Employing low-cost, environmentally friendly ink cleaning agents in production is undoubtedly an effective way for the industry to enhance operational efficiency.