The first step is face paper processing. The entire roll of ultra-thin calendered kraft paper and domestic kraft paper are processed into composite paper on a dedicated laminating machine. The adhesive is polyethylene PE, which is blown into a film at high temperature. The ultra-thin calendered kraft paper, polyethylene PE in the form of a thin film, and domestic kraft paper are sequentially bonded to form a composite paper. The coating amount of polyethylene PE is generally 10-15g/㎡.

The second step is inner paper processing. The entire roll of raw paper is coated with waterproof material on an imported coating machine. During the coating process, high temperature and high pressure are used to tightly bond the coating with the surface of the raw paper. During the coating process, the coating amount is accurately controlled by squeezing between the roller rollers. The coating amount of waterproof coating is 12-20g/㎡.

The third step is cardboard processing, which involves processing the surface paper, inner paper, corrugated paper, and paper core into corrugated cardboard on the corrugated cardboard production line, and cutting them into the required dimensions.

The fourth step is printing. The cut cardboard is printed on a water-based printing machine, and the printing content includes product logo, batch number, barcode, manufacturer and user specified graphics, text and other material information.

Step 5, die-cutting, the printed cardboard is die-cut into cardboard boxes of the customer's specified size and specifications on a touch cutting machine.

Step 6, inspection, sampling inspection of the sample box, including appearance and function. The appearance inspection is randomly selected from products from the same inspection batch, with minor defects including marking, printing, indentation lines, knife edges, box nails, bonding, lamination, and folding resistance of the shaking cover; The major drawbacks include internal scale, thickness, and moisture content; Functional inspection is extracted from qualified sample boxes for appearance inspection, which includes pressure, puncture strength, burst strength, adhesive strength, etc.

We also need to inspect the following items for the finished frozen aquatic corrugated cardboard boxes that are stored in the warehouse:

A. Coating quality of the inner and outer surfaces of frozen aquatic corrugated cardboard boxes

B. Use metal detection instruments to detect the possible presence of fine metal particles in the corrugated cardboard boxes of frozen aquatic products.

Five key points for detecting the content of heavy metals and harmful substances: lead, mercury, cadmium, hexavalent chromium, and arsenic.

Seven key microbiological tests: Escherichia coli, total bacterial count, Staphylococcus aureus, Salmonella, Listeria monocytogenes, Vibrio parahaemolyticus, and Vibrio cholerae.

Step 7, disinfection and packaging. UV sterilization and disinfection should be carried out on qualified products to prevent secondary contamination during storage and transportation in the future. Finally, it is necessary to seal the products with heat shrink film.