The first step is surface paper processing. The whole roll of ultra-thin calendered kraft paper and domestic kraft paper are processed into composite paper on a special duplicating machine. Polyethylene PE is used as the adhesive to blow into a film at high temperature. The ultra-thin calendered kraft paper, polyethylene PE in film form and domestic kraft paper at the composite are bonded in turn to form composite paper. The coating amount of polyethylene PE is generally 10-15g/ ㎡.
The second step is the lining paper processing. The whole roll of base paper is coated with waterproof material on the imported coater. During the coating process, high temperature and high pressure are used to closely combine the coating with the surface of the base paper. During the coating process, the coating amount is accurately controlled through the extrusion between rollers. The coating amount of waterproof coating is 12-20g/ ㎡.
The third step is cardboard processing. The face paper, lining paper, corrugated paper and paper core are processed into corrugated cardboard on the corrugated cardboard production line, and cut into the required dimensions at the same time.
The fourth step is printing. The cut cardboard is printed on the water-based printing machine. The printing content includes product logo, batch number, bar code, graphics, text and other material information specified by the manufacturer and the user.
The fifth step is die-cutting. The printed cardboard is die-cut into cartons of customer specified dimensions and specifications on the die-cutting machine.
Step 6: check and sample the sample box, including appearance and function. The appearance inspection shall be randomly selected from the products of the same inspection lot. Light defects include signs, printing, indentation lines, knife edges, box nails, bonding, mounting, shaking cover and folding resistance; Major defects include internal dimension, thickness and moisture content; The functional inspection shall be taken from the sample boxes that pass the appearance inspection. The functional inspection includes the pressure degree, puncture strength, bursting strength, adhesive strength, etc.
For the warehoused corrugated boxes of finished frozen aquatic products, we also need to check the following items:
A. Coating quality of inner and outer surfaces of corrugated boxes for frozen aquatic products
B. Use the metal detector to detect the fine metal particles that may exist in the corrugated boxes of frozen aquatic products.
The content of heavy metals and harmful substances was detected in 5 items: lead, mercury, cadmium, hexavalent chromium and arsenic.
Seven key microbial tests: Escherichia coli, total bacterial count, Staphylococcus aureus, Salmonella, Listeria monocytogenes, Vibrio parahaemolyticus and Vibrio cholerae.
Step 7: disinfection and packaging. The qualified products shall be sterilized by ultraviolet ray. In order to prevent the products from secondary pollution during storage and transportation in the future, they shall be sealed with heat shrinkable film.
