How to deal with the problem of heat sealing strength difference of bag-making machine?
How to deal with bad heat sealing strength of plastic bag making machine?
Reasons :(1) the adhesive in the composite film has not fully hardened;
(2) Improper heat sealing conditions of plastic bag making machine;
(3) The distance between heat sealing knife and cooling knife is too long;
(4) There is a problem with the inner sealing film;
(5) The inks heat sealing is poor, resulting in heat sealing part of the film composite strength reduced;
(6) Dust, dusting and other substances attached to the thermal cover;
(7) The composite strength is low or the composite strength at the heat seal decreases too much.
Countermeasures :(1) Promote the adhesive hardening (curing and curing) through heat preservation aging, improve the composite strength and heat resistance of composite film.
(2) According to the structure of the composite film, heat sealing state, choose the best heat sealing conditions (temperature, time and pressure), or improve the heat sealing mode, immediately after heat sealing cooling.
(3) Check the storage period and storage conditions of the heat sealing layer film. If the heat sealing layer uses the old batch number of film and the film after heat sealing treatment, special attention should be paid.
(4) Increase the thickness of the heat sealing film.
(5) Change the type and grade of the heat sealing layer film, and use the inner sealing layer film with anti-pollution heat sealing.
(6) Check whether the grade of the adhesive meets the requirements (the exudation of low molecular substances in the resin will sometimes affect the composition of the adhesive).
(7) Improve the thermal bonding performance of heat sealing layer (substrate), control the content of smooth agent, and use LDPE film.
(8) Control the monomer content of MDI in the composite adhesive.
(9) Check the treatment degree of the hot cover.
(10) replace ink (preferably with two liquid ink).
(11) Change the printing pattern of the packaging bag, so that the printing ink part avoids the heat sealing part, or change the heat sealing method of plastic bag making machine. (Pay special attention to metal ink do not print on the seal).
