1.0.0 Laminating Process/Dry&Wet Process

1.0.0 Laminating process
Basic Theory
Many products require special characteristics such as very strong seal, a low water vapor, perhaps some additional strength and stiffness, etc. But all impossible to achieve many of these needs with only single one material. So, converter perform the act to combining several substrate together. The process for doing this combining is called Laminating process. There are two kinds of laminating processes today :

1.Wet Laminating
2.Dry Laminating

Wet Laminating
Description :
Wet Laminating, in this process, the adhesive applied to the first web and then combined with the second web before drawn through a drying tunnel and the solvent is dried through the porous substrate like a paper. The adhesive used are water based, so there is no risk of residual solvent odors. A very popular adhesive is neoprene latex thicked with casein, available from many adhesive suppliers.

Application
Wet Laminating can be used for combining almost any film to a porous substrate like paper

Dry Laminating
Dry Laminating, in this process, the adhesive applied to the first web and then drawn through a drying tunnel before combined with the second web. In Dry Laminating, you can use either adhesive from solvent based or adhesive from water based.

Application
Dry Laminating can be used for combining almost any film to a film substrate

Tips for you.
For Wet Laminating, the adhesive applied must be too low in viscosity since it might then penetrate the paper too rapidly. Yet, if the viscosity is too high, it might coat poorly. A Satisfactory viscosity is in the neighborhood of 100 cps.

In Dry Laminating, specially used adhesive solvent based, the bonding strength can be achieved easily rather than adhesive water based. So, never using adhesive water based in producing laminate film for product that must be boiled such as retort packaging. ( will be explained later )

Never process the out put laminate material at least 1x24 hours until the full performance of The Bonding Strength achieved. The time needed to get this full performance called Aging Time. Some process need aging time till 2x24 hours

For Dry Laminating, specially combined film to film or film to Aluminium Foil, commonly using adhesive solvent based , 35 % solid content minimum, viscosity around 270 cps ( Zahn cup No.4, 22-25 second ) for speed 100-125 m/min

References :
Adolph Miller,Ch.E, Converting for Flexible Packaging, 1994, Technomic Publishing Company,Inc, ISBN : 1-56676-061-5,Switzerland