The complex strength of the colored part of the composite film is lower than that of the non-colored part.
In addition, the temperature at the time of heat sealing is high, so the heat seal strength at the colored place is low.
When designing a printed pattern, the edges of the heat seal should be left as empty as possible.
How to print patterns or white ink bottom. Longitudinal mechanical strength ratio of film
In the high direction, the longitudinal heat seal strength of the composite film is also higher than the transverse heat seal strength.
Therefore, try to use horizontal layout for printing patterns to avoid the top of the bag.
Severe necking at the time of wide-segment heat sealing also reduces the bag breakage rate.