Copyright. © The Dow Chemical Company (1995-2017). All Rights Reserved. © Trademark of The Dow Chemical Company("Dow") or an affiliated company of Dow.
Troubleshooting Guide
Sometimes problems come up. Below are several common issues and suggested solutions. Don't see what you are looking for? Contact us for additional technical support.
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YOU ARE TROUBLESHOOTING: PROBLEM: Bubbles in Lamination + CHANGE
Bubbles in the lamination are visible voids between the 2 laminated webs. The voids may be consistent in shape or highly irregular. Voids may be in machine direction or randomly dispersed accross lamination. I some cases the voids may look like haze without proper magnification.
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YOU SELECTED: PROBLEM: Adhesive is not uniform going into oven. + CHANGE
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Based on your criteria, we recommend the following:
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SOLUTION: Improve lay down of adhesive onto primary web
Steps to improve lay down are as follows:
1) Choosing correct solids to apply adhesive as well as correct cylinder choice.
2) Use of smoothing bar to help level adhesiev after application
3) Insure dyne level on primary web is high enough to accept adhesive and allow proper flow and wetting.
4) Adjust temeprature of adhesive puddle and dosing roll pressure on solventless adhesives.
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YOU SELECTED: PROBLEM: Outgassing in barrier to barrier laminations + CHANGE
Many dual component urethane adhesives give off some level of CO2 during cure, barrier to barrier laminations do not allow release of this CO2 causing bubbles gas to be trsapped creating bubbles
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Based on your criteria, we recommend the following:
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SOLUTION: Work with adhesive supplier on possible adhesive selections
Some adhesives will work in this application depending on end use. Discuss with adhesive supplier
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YOU SELECTED: PROBLEM: Improper nip roll setting and hardness + CHANGE
Using a nip roll that is too soft, creating a footprint creater then .5" and/or not enough nip pressure on nip roll can cause inadequate wetting of secondary web to primary web causing voids.
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Based on your criteria, we recommend the following:
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SOLUTION: Increase nip pressure and/or check durometer of nip roll
Ideally nip roll should be 85-95 shore A durometer. Guidelines for nip pressure often is 30-40 psi
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YOU SELECTED: PROBLEM: Improper use of smooting bar + CHANGE
When a smoothing bar is needed to improve flow/leveling of adhesive steps must be made to use it properly to insure optimum benefits of the bar
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Based on your criteria, we recommend the following:
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SOLUTION: Keep smoothing bar clean.
It is very important to keep smoothing bar clean. It should be cleaned every time the line stops. A dirty bar will not smooth adhesive uniformly and in some cases make the lamination look worse.
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SOLUTION: Normal size of smoothing bars are 1 ½ - 2 inches in diameter.
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SOLUTION: Smoothing bar should be driven by independent variable speed air motor.
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SOLUTION: Smoothing bar should be located within 6 inches of application head.
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SOLUTION: Smoothing bar should operate in reverse direction to web path.
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SOLUTION: There is no correct speed for all adhesives and substrates, vary speed to get best result.
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YOU SELECTED: PROBLEM: Improper mixing of adhesive and recirculation of adhesive + CHANGE
If adhesive is mixed improperly foam can be generated which will then applied to primary web. Bubbles are often seen in machine direction. Turbulance in pan due to recirculate pump running at too fast a rate can also cause this. In addition free fall of adhesiev into sump can cause this.
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Based on your criteria, we recommend the following:
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SOLUTION: Proper mixing and adhesive feed
1) Ideally overflow pipe should be located under adhesive level to prevent "free fall" creating bubbles
2) Slow feed pump to prevent surging into pan. Keep pump at just enough feed rate to keep pan full
3) Use proper mixing procedures for dual component adhesives to prevent foaimg during mixing. Use correct diameter blade to create vortex but not create foaming. Mix only long enough to incorporate both components do not overmix
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YOU ARE TROUBLESHOOTING: PROBLEM: Fish Eyes + CHANGE
Fish eyes are visible defects in the laminated webs that look similar to a crater. These areas are often relatively large and randomly dispersed
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YOU SELECTED: PROBLEM: Poor wetting of adhesive on primary substrate. This is a result of low surface tension on surface of film or coating. + CHANGE
Low surface energy on the primary surface(film, ink, coating, etc.) prevents adequate adhesive wet out of this surface creating the fish eye appearance.
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Based on your criteria, we recommend the following:
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SOLUTION: Retreat of primary surface to be laminated ,in line, is good insurance against this problem
Retreat (corona discharge) of film or surface to be laminated, in line is good insurance against this problem. Solvent based adhesives require a minimum of 36 dynes, and water based adhesives require minimum dyne level of 38-40.
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YOU ARE TROUBLESHOOTING: PROBLEM: Haze in lamination + CHANGE
Haze in a lamination is a reduction in clarity of the film or adhesive most pronounced in window areas of the package or lamianted film. Causes reduction in visibility into package.
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YOU SELECTED: PROBLEM: Low nip pressure + CHANGE
Low nip pressure causes inadequate adhesive wetting of secondary substrate leading to voids which can create a hazy appearance
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Based on your criteria, we recommend the following:
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SOLUTION: Make sure durometer of back up roll is 85-95 shore “A” durometer.
Apply enough pressure to give uniform footprint across web of no more than 0.5 inches, often 30-40 psi.
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YOU SELECTED: PROBLEM: Low nip temperature. + CHANGE
Low nip temperature prevents adequate re softening of the adhesive and prevents proper wetting of the secondary web thus creating voids which can create a hazy appear acne
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Based on your criteria, we recommend the following:
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SOLUTION: 150° - 180°F nip temperature is recommended. Run highest nip that will not distort lamination.
Proper nip temperature allows proper secondary film wetting. Consult adhesive TDS or adhesive supplier for proper nip temperature settings
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YOU SELECTED: PROBLEM: High water retention in water based adhesives. This results in milky look in lamination. + CHANGE
Water retention due to improperly dried water based adhesive's lead to a milky appearance in the lamination
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Based on your criteria, we recommend the following:
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SOLUTION: Make sure web temperature is between 160° - 180°F, or highest temperature that web can be exposed without distortion or curl.
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YOU SELECTED: PROBLEM: Low adhesive coating weight can result in poor wetting of secondary web. + CHANGE
Low adhesive coating weight can result in poor wetting of secondary web due to insufficient adhesive to adequately flow and level creating voids which create a hazy appearance in lamination.
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Based on your criteria, we recommend the following:
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SOLUTION: Increase coating weight by changing to higher running solids or low line screen cylinder, which puts on more adhesives.
1.25 lb/ream of adhesive suits most applications; however, certain inks and heavy gauge films may require 1.75-2.0 lb/ream to resolve problem.
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YOU ARE TROUBLESHOOTING: PROBLEM: Ink Bleeding with 100% Solids Adhesives + CHANGE
Ink bleeding is a reduction in print quality or crispness of the print job. Edges of the print are no longer crisp and show outward movement into the non print area.
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YOU SELECTED: PROBLEM: Components of 100% solids adhesives can solubilize certain components of ink systems cuasing ink bleed + CHANGE
Components of ink systems including glycols can be re-softened by some 100% solids adhesives, resulting in bleeding.
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Based on your criteria, we recommend the following:
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SOLUTION: Ink companies are adding more and more glycols to improve flow in inks to give better clarity on flexo presses
Ink companies are adding more and more glycols to improve flow in inks to give better clarity on flexo presses. If there is an ink bleeding problem, work with both the ink and adhesive suppliers to resolve the problem.
1) Insure inks are fully dried by running GC Head space on dried printed webs, work with ink supplier on proper drier settings
2) Run ink smear testing on fully dried inks with chosed solventless system, work with adhesive supplier on running this compatibility test
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YOU ARE TROUBLESHOOTING: PROBLEM: Low Bonds + CHANGE
Low bonds are any reduction in inter ply bond strength from the normal bond values seen. Low bonds can reduce the integrity of the package and lead to a variety of package defects.
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YOU SELECTED: PROBLEM: High alcohol content + CHANGE
High alcohol content from inks or alcohol contamination in solvents when using NCO containing adhesives.
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Based on your criteria, we recommend the following:
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SOLUTION: Maximum drying temperature of inks without distortion of web.
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SOLUTION: Run G.C.’s on all printed webs.
Less than 1,000 mg/ream total solvents are desirable. .-OH bearing inks may react with isocyanate portion of adhesive and/or plasticize. Confirm solvent via GC/MS, look for capping via NMR and SIMS/MALDI
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YOU SELECTED: PROBLEM: High solvent retention in lamination. + CHANGE
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Based on your criteria, we recommend the following:
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SOLUTION: Max web temperature without distortion of film. Normal web temperature for most laminations are 150° to 180°F.
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SOLUTION: Run G.C.’s on all laminations (less than 2,500 mg/ream as maximum).
Some end users want less than 1,000 mg/ream. May follow with GC/MS if unknown peaks present
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YOU SELECTED: PROBLEM: Low nip pressure. + CHANGE
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Based on your criteria, we recommend the following:
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SOLUTION: A back up nip roll with durometer of 85-95 is desirable for laminating adhesives.
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SOLUTION: Increase pressure to maximum without creating a uniform foot print across the web of more than 0.5 inches.
Often 30-40 psi on nip roller recommneded but foot print of .5 inches should not be exceeded.
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YOU SELECTED: PROBLEM: Low nip temperature for adhesive used. + CHANGE
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Based on your criteria, we recommend the following:
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SOLUTION: Increase nip temperature to maximum without causing any web distortion.
150°-180°F is normal; however, some high performance adhesives with high molecular weight can require nip temperature
> 200°F.
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YOU SELECTED: PROBLEM: Low treatment of films + CHANGE
Low treatment of films (less than 36 dynes for solvent adhesives and 40 dynes for waterbased adhesives.
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Based on your criteria, we recommend the following:
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SOLUTION: Corona retreat the films if possible as insurance that the surface energy is acceptable.
Use of fresh pretreated films is desirable. Even with this it is advisable to "bump" treat films at a 1 watt density to help insure clean laminating surface. For older films or films that have not been pretreated a higher watt density will be needed. Treating to achieve a dyne/cm reading of 36 dyne/cm for solvent based adhesive's and ideally 40 dyne/cm for solventless and waterbased is recommended.
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YOU SELECTED: PROBLEM: Poor anchorage of adhesive contact layer on the base film (PVDC,EVOH, metal, ink, etc.) + CHANGE
The adhesive bond can only be as good as the anchoring of the layer it is adhering to. This may include:
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1) PVDC coating
2) EVOH co extrusion
3) Inks
4) Metalization
Often as cross hatch adhesion test can be run on these film coatings prior to laminating to insure adequate anchoringTHAT'S ALL WE NEED TO KNOW
Based on your criteria, we recommend the following:
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SOLUTION: Film supplier will have to correct problem of anchorage.
Work with supplier of coated film of ink supplier when issues arise with poor anchoring of these coatings
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YOU SELECTED: PROBLEM: Poor ink adhesion-additives + CHANGE
Poor ink adhesion-additives such as anti-blocks, glycols, and other OH additives can adversely affect adhesion of sensitive NCO terminated adhesives.
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Based on your criteria, we recommend the following:
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SOLUTION: Ink companies supply inks that are suitable for adhesive systems being used.
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SOLUTION: Make sure ink companies know adhesive which is being used.
Run NMR, SIMS and MALDI to determine end-groups on chloroform extractable species from adhesive.
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YOU SELECTED: PROBLEM: Poor mix ratio on two component adhesives. + CHANGE
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Based on your criteria, we recommend the following:
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SOLUTION: Make sure balances are accurate.
Use high resolution balance for coreactants. Platform scales are not accurate enough for small amounts of coreactant. Confirm via FTIR Mix adhesive for five minutes minimum on any two part system. (Air mixer)
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YOU SELECTED: PROBLEM: Too high slip levels or contaminants in film. + CHANGE
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Based on your criteria, we recommend the following:
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SOLUTION: Corona treat high slip film in line to help insure that film surface is prepared to receive adhesive. Often can confirm via FTIR
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YOU SELECTED: PROBLEM: Too high water retention when using water-based adhesives. + CHANGE
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Based on your criteria, we recommend the following:
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SOLUTION: Clarity of web is first indicator that water-based adhesives are dry (no milky appearance).
However, web can be clear and still have too much water retention.
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SOLUTION: Good air volume in dryer will allow lower web temperatures.
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SOLUTION: Run maximum drying temperature without distortion of web. 160° to180°F web temperature is normal for water.
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YOU ARE TROUBLESHOOTING: PROBLEM: Poor Heat and Chemical Resistance + CHANGE
Poor heat and chemical resistance is any reduction in the ability of the adhesive to withstand heat or chemical exposure from what was considered normal. Reduction in heats resistance can effect ability to be heat sealed or withstand external heat source in package. Reduction in chemical resistance can effect ability to withstand internal package contents or external chemical exposure.
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YOU SELECTED: PROBLEM: Glycols and other OH groups can terminate or slow cure in NCO curing adhesives. + CHANGE
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Based on your criteria, we recommend the following:
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SOLUTION: Make sure inks you use are laminating grade for NCO curing adhesive.
Make sure inks you use are laminating grade for NCO curing adhesive. (Consult Ink manufacturer to confirm). Insure inks you are using are completely dried prior to laminating. Confirm using GC head space and insure GC trace picks up any high boiling solvents that may impede cure by reacting with adhesive
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YOU SELECTED: PROBLEM: High alcohol retention in lamination can terminate cure of isocyanate adhesives, which are sensitive to OH groups. + CHANGE
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Based on your criteria, we recommend the following:
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SOLUTION: Make sure you use urethane grade solvents.
Make sure you use urethane grade solvents. (99.0 + % pure) (Very low alcohol + water) Make sure retain solvents of inks are low in particular alcohol retention. Run G.C.’s to confirm low retained solvents. GC/MS to identify unknown species
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YOU SELECTED: PROBLEM: Incorrect mix ratio + CHANGE
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Based on your criteria, we recommend the following:
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SOLUTION: Proper mixing of two-component adhesives. Confirm via FTIR
Steps to prevent incorrect mix ratio
1) Consult adhesive TDS for proper mix ratio
2) Insure balances used to weigh components are accurate for weights being used and properly calibrated
3) Insure adhesive is properly mixed by using correct mixing blade for container size, insure adequate vortex during mix and allow for proper mix time
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YOU SELECTED: PROBLEM: Inadequate adhesive cure + CHANGE
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Based on your criteria, we recommend the following:
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SOLUTION: Insure proper cure conditions
To insure proper cure :
1) Follow cure guidelines on TDS for length of time needed to further process lamination
2) Do not store adhesive laminate below 60F if possible during cure cycle. A hot room can be used to accelerate cure often set at 115F
3) Do not ship lamination before cure completed in winter months if at all possible.
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YOU ARE TROUBLESHOOTING: PROBLEM: Telescoping + CHANGE
Telescoping is a phenomenon seen on the rewound laminated roll in which there is horizontal movement of the layers leading to uneven ends or roll. Slippage may be within the laminated film layers or between film layers themselves
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YOU SELECTED: PROBLEM: Can be related to air trapped between film layers on the roll. + CHANGE
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Based on your criteria, we recommend the following:
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SOLUTION: Adjust lay down roll to remove the air when winding. Assure even loading of lay-on roll.
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YOU SELECTED: PROBLEM: Improper tension/taper on the rewind. + CHANGE
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Based on your criteria, we recommend the following:
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SOLUTION: Check tension and taper control on rewind to get a wound up roll that is tight, but not too tight to cause this problem.
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YOU ARE TROUBLESHOOTING: PROBLEM: Tunneling + CHANGE
Tunneling is a phenomenon in which narrow tunnels or pipes form within the laminate layer. Often seen forming in the heat seal edge and working inward but can occur anywhere in package.
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YOU SELECTED: PROBLEM: Caused by web tension imbalances and improper rewind tension and taper. + CHANGE
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Based on your criteria, we recommend the following:
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SOLUTION: Make sure tension and taper are proper.
When two webs are pulled though machine at mismatched elongations they will return to normal state once tension is relieved. The adhesive can only reduce this movement slightly(thus causing laminate curl) this will result in tunneling in lamination. It is important to adjust web tensions so that each film elongates roughly the same amount through process.
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YOU SELECTED: PROBLEM: Excessive coating weight. + CHANGE
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Based on your criteria, we recommend the following:
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SOLUTION: Normal coating weights for lamination are between 1.0 and 2.0 lb/ream.
Adjust tension and taper on rewind to prevent the adhesive from moving cohesively until adhesive is cured. This isa problem mostly associated with solventless adhesives which have littel cohesive strength until cure initiates.
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YOU SELECTED: PROBLEM: Low bonds can allow extensible and non-extensible webs to move on each other + CHANGE
Low bonds can allow extensible and non-extensible webs to move on each other resulting in tunnels. Especially where adhesive cure is affected (alcohol contamination, high retained solvents, plus glycol and other OH contaminants).
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Based on your criteria, we recommend the following:
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SOLUTION: Review caused and solutions in low bonds. Confirm capping via NMR, SIMS, MALDI
Low bonds caused by poorly cured adhesive should be corrected in the following manner:
1) Insure correct mix ratio is being used and balances used to weigh are calibrated.
2) Insure adhesive is adequately cured by following recommended cure guidelines on TDS(Consult adhesiev supplier for cure guidelines as needed)
3) Insure only urethane grade solvent are used for diluting adhesive's when dilution required
4) Insure inks are properly dried prior to laminating by running GC head space for solvent retention. (Consul ink supplier to insure inks are lamination grade)
5) Insure films are treated to adequate dyne level to allow proper adhesive bonding
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