Because of BOPA material belongs to easy to moisture absorption and moisture absorption after the barrier property greatly decreased, thus in high humidity climate, if do not take the influence of humidity, will have serious quality accident.
BOPA in printing, composite process, due to the moisture absorption membrane, the surface form a layer of small water droplets into omentum, block the adhesion of inks and adhesives and will produce the quality problems such as small air bubbles or white dots.
Hygroscopic makes BOPA material deformation overprinting difficulties, hygroscopic multiply residual solvent to produce anti adhesion phenomenon, moisture absorption increase high temperature cooking bags products torn bags, composite film feel is hard and brittle hair wait for a phenomenon, a serious impediment to the production process and the quality of the products, thereby causing loss to the difficulties and to manufacturer.
For this, put forward the following matters needing attention for reference.
(1) strictly manage BOPA materials.
BOPA materials of hygroscopicity strong, more should strengthen the management in this period of time, hold B 'must be put in dry environment, it is best to use namely out, if there is surplus production, should immediately with good barrier property of aluminum-plastic composite membrane sealed packaging, should not be stored directly on the ground, if conditional, ideally on curing chamber, pull out again when production use.
(2) to strictly control the production environment.
To strictly control the production environment, to prevent the humidity is too high, if more than 75% moisture in dehumidification process.
And auditing of guide roll, scraper and the net on the back roll on whether there is a small water droplets attached, once discovered immediately with a dry towel to wipe, if printing, composite machine preheating device, should make full use of, let BOPA after preheating out surface water for production.
(3) strictly control the quality of the solvent and use.
Ethyl acetate solvent water and glycol total content should be controlled in 0.
Below 2%, printing special ink application BOPA nylon film at the same time.
In mixed solvent ink, should as far as possible need not alcohol solvent, prevent ink 'table' phenomenon caused by the glue.
Were it not for you, also should try to minimize the residual solvents (when printed
Can cure after printing a day and then to compound)
(4) using polyurethane ink printing, available in white ink to add a small amount of printing ink curing agent, in order to enhance compound solid degrees.
In the deployment of dry type composite adhesives, appropriately increase dosage of curing agent (
Increasing ratio is fixed dose of 5% ~ 10%)
To ensure adhesive of main agent and curing agent ratio balance, can fill FenJiao, avoiding the phenomenon of not.
Improved compound process parameters in the drying box, must bring up the wind speed is greater than the wind speed, the more volatile solvent, reduce the residual.
In material by drying box under the premise of not deformation, appropriately increasing drying temperature for dry box, to ensure that the principle of increasing drying temperature from low to high,
In general drying temperature 60 ℃ -
Increasing 80 ℃)
5. Strictly abide by the curing time.
A variety of different USES of adhesive, its crosslinking curing time is different, the least common adhesives to 55 ℃ for 24 h/after curing bag.
And must be up to 72 h/cooking adhesives 60 ℃ to ensure crosslinking curing effect after curing, while avoiding excessive residual solvent volume phenomenon of heat sealing side,
Vacuum aluminum plating film curing conditions and different cooking bags)
6. Strengthen the production workshop environment temperature and humidity control.
General production workshop temperature at 25 ℃ + 3 ℃, the dry humidity of 65% plus or minus 5%, and should strengthen the ventilation and exhaust, desiccant when necessary.
'Plum rains season, because of the humidity is big, easy to cause a variety of flexible packaging product quality problems now, especially the use more easily hygroscopic materials (
, are more likely to produce sudden accident, to plan your work, to ensure the production smoothly.