SOLVENT-LESS LAMINATING TROUBLESHOOTING GUIDE

CONTENTS• Preparing the Adhesive• Mix Meter Dispense• Puddle and Application• Unwind and Rewind• Coat Weight • Adhesive Cure• Unwanted Influences • Bonds• Troubleshooting• Definitions• legal

• Isocyanate is extremely sensitive to moisture. When opening a barrel for the first time, care should be taken to ensure the cap or extraction tube are replaced on the bung hole cover. The 1.5” vent hole in the drum should have a desiccant cartridge permanently fixed to ensure only dry air is exchanged with the adhesive as it is dispensed from the drum.

• Allow the adhesive and co-reactant to reach the manufacturers recommended temperatures in the MMD before dispensing onto the metering rolls. Cold adhesive can increase the desired coat weight.

• Do not use the adhesive past the expired date. Generally 1 year from manufacture. Isocyanate will lose reactive groups over time and effect final curing and bond strength.

• Use only new static mixers at the beginning of each day or if the machine sits idle for longer than 45 min.

ADHESIVE PREPARATION

• Gear pumps are capable of precise metering on a continuous basis but require attention to ensure they are operating properly and maintain a precise mix ratio throughout the run.

• Measuring the mix ratio manually by separating the adhesive and coreactant stream from the mix head and weighing the components individually to ensure the ratio is correct is important to do on a daily basis. The OEM will have detailed instructions on how to perform this test.

• During the weighing process, do both streams of adhesive stop simultaneously? If not, then there may be an issue with a faulty check valve, cured adhesive in the dispense head or phasing of the pump. It’s extremely important that both streams stop simultaneously when you release the dispense button on the pump.

• Mix ratios should be set in the machine by volume. Each component will have volume ratio and a density on the tech data sheet, these should be confirmed with the adhesive manufacturer and input into the MMD separately to ensure correct mix ratio dispensing.

• Ensure you have the correct static mixer as recommended by the manufacturer, based on the viscosity of your adhesive.

• Static mixers should be changed on a daily basis or if the machine sits idle for longer than 45 minutes.• Temperatures of the pots and hoses are also important to ensure a smooth delivery of the adhesive and to

maintain a consistent mix ratio, coat weight and adhesive appearance.• Dispensing cold adhesive and running without allowing the adhesive to reach the manufacturers

recommended temperatures can lead to coat weight issues and an orange peel appearance of the adhesive.

MIX METER DISPENSE PREPARATION

• Ensure you set the gap between the metering rolls at the beginning of each day, only after they have reached the desired temperature.

• Ensure all heated rolls, including the laminator nip roll reach the recommended temperature before starting to laminate.

• Do not allow the mixed adhesive to sit in the puddle longer than 20-30 min before using, depending on the adhesive. This time could be shorter depending on the adhesive used. Mixed adhesive will react extremely quickly and build molecular weight. Coat weight will increase with the use of aged mixed adhesive.

• Confirm coat weight at running speed, only with freshly dispensed adhesive. Coat weight measurements with adhesive that is older than 20- 30 min, will result in a lower coat weight once you begin to run and consume fresh adhesive.

PUDDLE AND APPLICATION

UNWIND AND REWIND• Unwind tensions should be set to a minimum. You only need enough tension to ensure the

film tracks through the web guide and over the rolls without creasing.

• Rewind core should be clean and free of old web or debris. Nip rollers, lay on rolls application rolls and metering rolls should also be cleaned and completely free of dried adhesive or debris.

• Curl of the laminated web should be confirmed before beginning to laminate by cutting a X in the center of laminated film. If the film curls towards the sealant in the machine direction, you should decrease the secondary web tension, or if already low, increase the primary web tension.

• If the laminate curls towards the primary layer, generally an inextensible web, decreasing the primary layer tension or increasing the secondary web tension may help or there may be in roll tension from the supplier or drag somewhere in the machine creating excess tension under load.

• If the film curls in a cross web direction, decrease the laminator temperature or nip pressure. Make only one adjustment at a time before making further adjustments.

• The lay on roll should be used on all laminations. This roll ensures air is squeezed out between the film wraps. The ensuing roll pressure as you build the roll diameter will squeeze any unwanted air from between the laminated film layers. Ensure your taper/ tension is set to ensure tension reduction as the roll builds and to ensure enough roll pressure during the run. The higher the taper the less tension as the roll builds.

COAT WEIGHT• Coat weight is determined by manually measuring the amount of adhesive applied

across the laminated web. • Coat weight should be confirmed in three areas minimum, each side and the center of

the web. Depending on the width, you may need to measure more than one area in the center, spaced evenly.

• Measure coat weight with freshly dispensed adhesive at the desired temperature and at machine line speed.

• If there are no clear areas, use clear film or foil drop sheets to set up your machine and make adjustment to the application roll speed or gap to adjust the desired coat weight.

• Coat weight should be confirmed a the beginning of each run, after the first roll and at the beginning of each shift.

• Coat weight should be determined by the amount of ink present on the primary web and the end use application. The higher the ink coverage the higher the adhesive deposition. If the web is sealed by higher than normal temperatures above 450F / 230C a higher coat weight should also be used. Consult your sales rep for the appropriate coat weights.

• All isocyanate solvent-less adhesives are a two component mixture with a three component cure.

• Step one is ensure the adhesive is mixed properly, manually weighing the two components at the beginning of the shift is extremely important.

• The A part is mixed with the B part to create bonds and shear. The resulting mixed adhesive will still have reactive groups that will react with moisture on the web surface and moisture that was present in the air during lamination. This reaction creates Urea. Polyurea is extremely heat and chemical resistant.

• The first reaction between the A and B part is very fast. The adhesive builds molecular weight very quickly and creates bonds and film structure (shear).

ADHESIVE CURE

• The second reaction after the A and B parts has been mixed is with moisture. The moisture reaction is 10 times slower than the initial reaction between the A and B parts.

• Moisture is present on the film surface and in the air. There is an abundance of moisture in Summer months but in Winter as you begin to heat the plant, the moisture is dried from the air and the relative humidity drops to levels below the recommended levels of 35% RH. The drier the air the longer it will take your laminate to ultimately cure, unless the roll can be kept warm and the isocyanate active.

• To speed the moisture reaction and resulting final cure, ensure the plant air has a relative humidity of at least 35% and store the roll in storage at 35C. This will result in a cure time that is similar to hot summer months. Keep in mind, strong bonds are not an indication of final cure. The shear resistance of the adhesive is gained with the reaction between A and B parts. The ultimate test is can the laminate withstand heat, which is gained through the reaction with moisture and the formation of Urea within the adhesive layer.

ADHESIVE CURE

• OPA or Nylon films are hygroscopic and will compete for moisture in the laminate with the adhesive. When laminating with Nylon it is important to remember, if humidity levels are below 35% the cure time can also be extended by up to 50% or more.

• All adhesive cure begins when the two films are brought together in the lamination nip. There must be enough heat transfer to penetrate through both webs. A good measuring tool is to measure the temperature of the rewound roll during the run. The roll should register a minimum temp of 35C.

• It’s important to maintain the heat in the roll as long as possible through the storage process. Unwinding the roll prematurely dissipates any heat gained in lamination and slows the cure. Slitting or converting may result in unwanted tunnels or delamination, especially in winter if those slit rolls are loaded on a truck bound for your customer.

• Rule of thumb for adhesive cure. 10C below laminating temperature, the laminate may take twice as long to cure. 10C above laminating temperature the laminate may take ½ the time to cure.

ADHESIVE CURE

High retain solvents in print web. Any hydroxyl group or alcohol will react with the A component immediately to extend or completely terminate the final cure and urea

formation, reducing the heat and chemical resistance of the adhesive.

Henkel rule of thumb for retain solvents on incoming print web before lamination:

• Max- 0.71 mg/m² Combined Alcohols- Ethanol, Isopropanol, nP Alcohol.• Max- 0.36 mg/m² high boilers. Glycol Ether, PM, EP, DPM, etc.

• Max -5.4 mg/m² Ethyl Acetate.

UNWANTED INFLUENCESDISRUPTING ADHESIVE CURE

Causes of Air Entrainment:• Poor winding taper/tension or lay on pressure • Low coat weight • Poor surface treatment on film preventing the adhesive

wet out• Poor film gage• Dirty or damaged nip chrome or rubber roll• Inconsistent coat weight distribution from side to side• Dirty application roller

BUBBLESBubbles or air pockets are entrained air. A boundary layer of air moves with the web as your machine runs. The faster you run, the more air is moved. The idler rollers in the machine deflect the air and nip points should prevent most air from entering the laminate. Proper roll winding and lay on pressure are used to manage any remaining air from remaining in the laminate. Entrained air will pass through low barrier films such as LdPe and air will also escape from the side of the roll in storage.

Causes of Tunnels:• Incorrect adhesive mix ratio • Heat Sealing before the adhesive has fully cured• Excess mismatched elongation of films • Interference from retain solvents contaminating the

adhesive layer• Interference from a blown film additive contaminating the

adhesive layer ie: antistatic or slip• Expired adhesive or co-reactant

TUNNELSTunnels or post lamination wrinkles that manifest from the heat seal or zipper areas are created when the adhesive layer is plasticized by heat seals and the extensible film shrinks back to the pre stretched profile before laminating. Tunnels in the primary layer may not appear immediately after sealing, it may take 12-24 hours to appear.

Causes of Ink Smear:• Poor roll handling from rewind shaft to storage area• Higher than recommended retain solvents in print

web before lamination • Incompatible adhesive/ ink layer• Incorrect mix ratio. Generally higher B part• Excess adhesive layer in pre stretched film area

creating a gage band puddle

INK SMEARInk Smear is a result of the adhesive layer rewetting the ink layer in the laminate. Proper roll handling and winding techniques can solve most ink smear issues however some inks and adhesive are more sensitive than others.

Causes of Curl:• Incorrect tension of the primary or secondary web. Rule

of thumb - match elongation of films not tensions. LDPE, BOPP or OPA are more extensible than PET

• In wound tension from the film supplier in the master rolls

• Idler rollers bearings in need of repair • Excess heat in nip roll, this will generally show in cross

web direction or web edge curl• Insufficient cure time resulting in curl on web edges

after heat sealing

CURLCurl in the machine or web path direction is a result of two films being laminated with differing elongation. Curl in the cross web direction is generally a result of excess nip roll heat or pressure in the lamination nip.

Causes of Delamination:• Incompatibility between adhesive and the substrate• Poor surface energy of the substrates before lamination• Incorrect mix ratio of the adhesive, generally excess Polyol or B • Heat Sealing before the adhesive has fully cured• Excess slip or antistatic additive• Using old films. BOPP & LdPe especially can lose their treatment

when stored in excess of 3 months• Insufficient coat weight. Film to film a minimum of .8# or 1.6 Gms is

required

DELAMINATIONDelamination (or ‘Delam’) is when the laminated substrates separate easily or with little effort.

• Decal or inks or MET coating on films. The adhesive will adhere to inks or Met surface. If the bond between the ink or Met to the base substrate is lower than the bond of the adhesive or the ink or met coating, the ink or met coating will decal off the base substrate creating delam where the coating or inks are applied

• Out Gassing or protruding bubbles in the lamination is actually Co2, trapped in a high barrier laminate.

• Co2 is a bi-product of the reaction between Isocyanate and moisture. Co2 is generally passed through the film in the roll form but when laminating high barrier structures such as PET/EvOh CoEx sealant, PET/Foil, or PET/OPA, the Co2 can get trapped in the laminate and create protruding bubbles that you can actually feel on the surface of the film trapped in the laminate.

• Co2 will actually move around in the laminate. If there are many smaller bubbles in a solvent-less laminate before cure, movement can create larger bubbles and ink smear.

OUT GASSING

• Out gassing can be controlled with speed, roll winding pressure, controlled atmosphere in the plant and a good quality sealant material. Air will enter the laminate and moist air will react with the adhesive.

• Ensure the film has good gage profile and ensure your nip roll and rubber roll are clean and in good condition. Winding the roll as tightly as possible tapering off the tension as the roll builds around 20-25% will maintain good roll pressure combined with the lay on roll.

• Laminating on days that are less humid below 50% can also help.

OUT GASSING

Two types of Bonds:

BONDS

• Surface energy of films very important• Use of treater on the secondary sealant or inner layer, increases surface energy of films.

Cleans contaminates such as slip, antistatic, or back transfer residuals from matte coating from the web.

• Wet out of films requires heat through lamination nip to lower surface tension of adhesive, allowing it to flow and activating the adhesion to both substrates

• Proper Mix Ratio• Moisture, 35% RH minimum recommended for timely cure• Minimal residual solvent from print allowing the proper reaction between the adhesive,

co-reactant and moisture• 48-72 hrs. critical for development of full cure for cohesive bonds

ADHESIVE/ COHESIVE BONDS

• Isocyanate - This is the backbone of the adhesive. Also referred to as A part or simply adhesive.• Polyol - The curative. It also enhances the adhesive properties, flexibility and slip acceptance of

the final cured adhesive. Also referred to as the B part or co-reactant.• Static Mixer - The tube that mixes the adhesive before delivery to the puddle mounted at the

end of the dispense head.• Puddle, or metering rolls. The area where adhesive is deposited to condition before application.

This is also the area where you set your gap to meter the amount of adhesive applied.• MMD, Mix Meter Dispense - The mixing pump with separate vessels. There are two types of MMD,

the most popular is a gear pump. There are also fixed ratio piston pumps. • Primary Web / Unwind - This is the web where the adhesive will be applied. Generally the print

web or inextensible web. • Secondary Web/ Unwind - This is the web that is laminated to the primary web. Generally a

sealant web or metalized web in triplex applications.• Application Roll - A heated chromed smooth roll combined with an undercut neoprene roller

where adhesive is applied to the web.

DEFINITIONS

• Laminator Nip - A heated hard chromed smooth roll and a neoprene roll where the two intersecting webs come together to create a laminate.

• Lay On Roll - A hard aluminum or rubber roll that lays on top of the rewind roll squeezing the air from between the film layers as they wind on a core.

• Rewind - The area where a bare core is loaded to accept the laminated web. In conjunction with the lay on roll, the finished laminate is wound unto the core resulting is a smooth hard surface that enhances the appearance of the lamination.

• Cold Flow - This defines the movement of the adhesive once it is between the layers of film in roll form.

• Haze - Tiny pockets of air within the adhesive layer resulting from insufficient coat weight or insufficient roll pressure.

• Gassing - Tiny raised bumps or bubbles that are a result of isocyanate and moisture reaction. Generally only seen between two high barrier substrates. PET combined with an EvOh CoExsealant, foil or OPA. ( Nylon)

• Orange Peel - A mottled or orange peel appearance created by excess adhesive or insufficient roll pressure.

• Adhesive Strength - The strength of the adhesive bond to the substrate.

DEFINITIONS:

• RH Relative Humidity, it’s always good to have one at the machine especially in colder months and register the humidity levels on each production order.

• Surface Energy - The surface treatment of incoming films. Dyne pens or liquids should be changed according to expiry dates listed on the pens.

• Cohesive Strength - The strength of the adhesive layer when the films are separated.• Delamination - The laminated layer separate generally under pressure or heat.• Decal - When the adhesive layer attaches to an ink or Met layer and completely removes it from

the base web during film separation.• Tunnels - Wrinkles in the film outer surface seen after heat sealing, created by a plasticized

adhesive layer and film stretch from mismatched film elongation during lamination.• PAA - Primary Aromatic Amines are produced during the reaction between and aromatic

adhesive and polyol. Amines can travel through low barrier films and react with moisture or oils present in filling goods or food if filled before the adhesive has reached full cure. Aromatic Amines are a Carcinogen and in an active state during the curing process. Laminations should be allowed to reach full chemical cure before filling with food. Termination of aromatic amines is generally 24 and 72 hours depending on the type of adhesive used. Please check with your local representative for information.

DEFINITIONS:

We hope everyone gets something from this handbook. Understanding the components and how they function once mixed and applied to the web is important to successful laminations. As your adhesive supplier, we want to ensure you have the

tools not only the components to laminate successfully day in and day out. Our representatives across the country are a phone call or email away, If there is ever a question on anything related to laminating or issues that arise during or after the laminate is produced. we have priority access to Henkel’s center of excellence in Bridgewater NJ., and some of the best technicians and chemists in the industry.

YOUR LOCAL QUADRA REPRESENTATIVES:

Donald Brown (Winnipeg & Western Canada) don_brown@quadra.caBarry Cousins (Ontario) barry_cousins@quadra.ca Charles Babecki (Quebec & Eastern Canada) charles_babecki@quadra.ca

SUMMARY

LEGAL

The information provided in this Guide including the recommendations for use and application of the product are based on our knowledge and

experience of the products and application. Quadra or their suppliers are not liable for the suitability of our products for the production processes and conditions in respect of which you use them, as well as the intended applications and results. We strongly recommend that you carry out your

own tests internally to confirm such suitability of these recommendations.