Pre-design and material selection, paper bag design and manufacture are the key links in the whole paper bag production process. Most paper bags are an extension of corporate image and commodity advertising strategy, so the materials, decoration techniques and forms of expression are inseparable from the use and efficacy of paper bags. Kraft paper has good toughness, high strength and rough surface. Paperboard has good stiffness but poor toughness, so it usually needs surface coating when used as paper bag. Coated paper has certain toughness and rich printing colors, but its stiffness is worse than that of cardboard. Kraft paper is often used to emphasize durability, and cardboard is also often used when color and stiffness are important, but people often prefer coated paper because it needs colorful patterns. In order to improve the taste and grade of portable paper bags, designers have made great efforts in the surface decoration process after printing.

The flexible application of bronzing, UV, glazing, colorful, concave-convex and flocking also makes the paper bag colorful, stereoscopic and expressive. Of course, no matter what finishing process is adopted, designers should consider the economic utilization rate of paper materials and the rationality of process design. For production and quality control, it is essential to make a complete and clear set of operation engineering drawings during design, and in most cases, products need to be confirmed by proofing. Proofing in design is not only the verification of process, but also the basis for customers to confirm and produce samples. For printing and handbags, there are many colors in a big layout. It is recommended to use a high-quality printing machine for printing. A good printing machine has balanced ink control and good color brightness. Film covering, also known as post-press plastic coating, post-press plastic mounting or post-press film pasting, refers to the post-press finishing process of covering a layer of transparent plastic film with a thickness of 0.0 12 ~ 0.020 ㎜, which is generally divided into two processes: pre-coating and instant coating. According to the different film materials used, there are high gloss film and matt film. With the use of environmentally friendly aqueous solvents, the environmental protection of film mulching technology has been further improved. Non-kraft paper bags are mostly wrapped with plastic film, mainly because the plastic film can increase the color concentration, the product has good waterproof and antifouling properties, and the physical properties of paper such as aging resistance, tear resistance and puncture resistance are generally improved, which improves the fastness and strength of paper bags and obviously enhances the bearing capacity. Especially the use of matte film can give people a soft, high-grade and comfortable feeling.

Surface treatment, bronzing, UV, polishing and other printing surface treatment processes are widely used in portable paper bags. It greatly satisfies people's pursuit of exquisite and high-grade paper bags. In the production process, we should also control the key points in these technological links. Die-cutting processing, die-cutting technology is a process method that combines die-cutting knife and indentation knife on the same template, and uses die-cutting machine to die-cut and indentation printed matter, also known as "rolling mark". This is an important process in paper bag production. The quality of die cutting directly affects the forming quality of paper bags and the efficiency of manual pasting. Paste box and paste technology are the most special links in the production of portable paper bags. Except for the auxiliary use of some semi-automatic equipment, it is mainly done by hand, which is the least efficient link in the whole paper bag process. The demand for exquisite portable paper bags in developed countries is particularly huge, because it cannot be completed by automatic production lines, which provides business opportunities for the export of paper bag products of many printing and packaging enterprises in China.