1, What is coating iron?
A, coating iron: coated tin (or chromium) thin steel plate referred to as coating iron
B, coating iron classification: tin plate (referred to as tinplate) and chrome plated iron (referred to as chrome plated iron)
C. Coating iron application: In addition to light-colored fruits and individual vegetable varieties, dark-colored fruits (fruits with flower phenotype, high acidity, high nitrate content, iron-sensitive foods, sulfur-containing foods, and foods to be molded All need to use coated iron packaging;
2, coating iron quality requirements:
A, in line with food hygiene requirements;
B, the film should be uniform, less microporous, that is dense;
C, has a good mechanical processing performance;
D, good bactericidal performance
The main factors affecting the quality of coating iron:
1, tinplate performance;
2, coating materials
Epoxy phenolphthalein coating, PVC organic sol coating, aluminum paste coating, zinc oxide coating, vinyl coating (ie full-spray coating)
3, solvent and machine viscosity:
Solvent: different coatings require different solvents and thinners to increase the wettability of the coating to the tinplate surface and allow the coating to be in intimate contact with the substrate to enhance adhesion.
On the machine viscosity: should be controlled in the appropriate range, the viscosity is too low, easy to produce sagging, viscosity is too high, poor leveling, then reported to produce bubbles and pinholes;
4, baking curing
The coating must be properly roasted to allow the resin to fully crosslink to form a continuous, uniform polymer network. When the barbecue is insufficient, the coating film has poor compactness and porosity. As a result, it poses a danger to food safety.
5, coating thickness
The coating film porosity is inversely proportional to the thickness, and when the film thickness is increased by 1.7 μm, the porosity will be