Knowledge of common composite film production process
composite film process standard process parameters
composite key parameters:
oven temperature: 50 - 60℃； 60 - 70℃； 70 - 80 ℃
composite roller temperature: 70 - 90 ℃
composite pressure: without damage to the film, should enhance the composite roller pressure as much as possible.
about several details:
( 1) Transparent thin film composite, the temperature of the oven and composite roller and the ventilation within the oven ( Wind, wind speed) For transparency, for the temperature when the PET printing film with ceiling; When printing film of BOPP temperature using the lower limit.
( 2) For PET composite aluminum foil, such as printing membrane, composite roll temperature must be higher than 80 ℃, usually in the 80 - Adjustment between 90 ℃ and printing film of BOPP compound roll temperature does not exceed 80 ℃.
* curing
( 1) Curing temperature: 45 55℃
( 2) Cure time: 24 - 72 hours
a two-component glue in composite board does not immediately after have ideal bond strength, 45 - need to send products to curing room Curing under 55 ℃ - 24 72 hours, Common transparent bag for 24 hours, 48 hours aluminum foil bag, retort pouch, 72 hours) And curing room ventilation is very important also, adequate ventilation can reduce assimilation time, but also can further reduce the residual solvents.
the preparation of the adhesive solution
standard preparation methods: first, the main agent into the plastic barrels, pour 1/3 after solvent dilution, stir well, add hardener, edge and stirring. Even after add residual solvents.
the current common practice is: all pour into solvent, the main agent again stir in all the curing agent, this should be easy, but the glue solution with good performance for the dependence of the solvent used is very big, the current domestic ethyl ester as formaldehyde method to produce more, which is of very high alcohol content, sometimes the manufacturer will find what process haven't changed, peel strength of composite film has suddenly become very bad, I encountered this kind of situation, in a lot of manufacturer change with glue method, strength.
the use of residual adhesive solution
the remaining glue solution after 2 times dilution, seal, when the next day, as the thinner, the incorporation of new adhesive solution, with high requirement of products, not more than 20% of the total. If the solvent water qualified, with good adhesive agent for 12 days no big change, but as a result of composite good film can't determine whether qualified, residual adhesive solution directly use may cause great damage.
why transparency
* incorrect adhesive
( 1) The adhesive itself color depth;
( 2) Poor adhesive illiquid, flattening and cannot fully spread out on the base film;
tell commonly, the main agent of solid content is higher, the better the liquidity, to spread out in the film, so on the market at present 75% than 50% plastic transparent effect is good, is better than that of 40%, 50% for the high demand for transparency of composite membrane, 50% and 40% rubber are hard to meet the requirements.
* process problems
( 1) Bake, inlet temperature is too high or no temperature gradient, inlet temperature is too high, dry quickly, make the glue layer on the surface of the solvent evaporated quickly, surface crust, and then after the internal heat into the glue liquid layer, under the skin membrane solvent gasification, break through the film formation volcanic vents that ring, a circle a circle, also make the rubber is not transparent.
( 2) Compound rubber roller or scraper flawed, and can not point pressure, formation of gap, opaque.
( 3) Environment too much dust in the air, after the glue drying and hot air blowing entered in the dust. Glue on the rubber surface, composite sandwiched between two sheet base film, there are many small points, opaque, solution: high mesh filters are available to eliminate hot air inlets in the dust.
( 4) The gluing quantity is not enough, there is a blank space, with small air bubble, causing tinea or opaque, please check the amount of glue, so that it is enough and uniform.
( 5) No fair rubber roller or rubber roller is not clean.
* base material:
surface tension is not high adhesive solution for its invasive is not enough, cause uneven film after drying, bit by bit, commonly known as 'pockmarked face film.
composite membrane with small bubbles
* raw material:
( 1) Basal membrane surface tension is too low, invasive poor;
( 2) Thinner, the moisture content is too high, the water react with curing agent in the NCO to generate CO2 formation of bubbles.
* process:
( 1) Compound rubber roller pressure is insufficient or steel roller surface temperature is too low, adhesive activated is insufficient, lack of liquidity, branches of adhesive flow, a tiny gap of tiny bubbles.
( 2) Compound roll and the Angle between the membrane is not appropriate, Angle is too large, according to tangent into the composite roll as far as possible.
( 3) Dirty air humidity is too big, workshop environment, a dust adhesion on the surface of membrane, the dust will be two membrane jacking, forming a circle around gap, coarse watch is a little bubble, see a black dot in the middle.
the problem of composite membrane fat from
