Most flexible packaging manufacturers do not have the conditions to establish a benzene-free workshop in the process of changing from benzene printing ink to benzene-free printing ink. Usually, benzene printing and benzene-free printing are carried out simultaneously in the same workshop.
Sometimes even printing and composite workshop is not separated, so that to achieve benzene residue free products in the benzene space environment printing and composite, its effect will be greatly reduced. Let us now review the several stages of benzene residue!
1. Benzene residue is greater than 2mg/㎡ stage
Chlorinated polypropylene has benzene ink for large area full plate OPP film printing, the composite thermal cutting bag of the finished product of benzene will generally exceed the QS quality safety requirements of benzene is not more than 2mg/㎡ requirements.
The amount of benzene residue depends on the drying capacity of printing equipment, the release of ink resin to benzene and the amount of ink in the layout.
2. Benzene residue is less than 2mg/㎡ stage
Since the implementation of QS quality and safety certification, the more standardized packaging materials using enterprises will benzene small 2mg/㎡ standard is clearly included in the incoming inspection of packaging materials.
The packaging enterprise is required to provide the corresponding inspection report, and the well is required to check the packaging material. Such flexible packaging enterprises began to gradually use environmental ink printing. Not only does the weight of toluene decrease, but the cost also decreases.
3 benzene residue is less than 0.1mg/㎡ stage
In the first two months of GB/T10004-2008 implementation, in order to make the benzene residue of the packaging bag meet the requirements, the series of packaging bag of benzene soluble ink replaced by benzene free modified chlorinated polypropylene ink.
But due to some technical reasons, small areas of special color and light mesh part still use benzene soluble ink. The residues of this series of products produced during this period of time were detected, and the toluene content distribution was shown in the figure
