TYCEL 3740

Target Application

Designed as an economical adhesive system for high performance film/film and film/foil food packaging laminations that require heat and chemical resistance. Its primary use is for laminations exposed to pasteurization, boiling water, and sterilization.

Other Applications

This adhesive also can be used for general-purpose food packaging laminations, health care, pharmaceutical and cosmetic applications.

 % Running Solids

Determine the adhesive viscosity based on your application method, cylinder selection and desired coating weight. Typically, a coating weight between 1.5 – 2.5 lbs/ream (2.4-4.0 gm/m² ) is used for standard laminations. The chart below may be used for reference and is typical for TYCEL 3740/LOCTITE LIOFOL LA 6055 when diluted with Ethyl Acetate.

Solvent Selection

Select a dilution solvent. Urethane grade ethyl acetate is recommended. However, methyl ethyl ketone or acetone may also be used. Using a solvent other than ethyl acetate will change the viscosity curve shown above. Calculate the amount of solvent required to dilute the adhesive and curing agent to the desired % running solids. 

Adhesive Mixing
Weigh the desired amount of adhesive into a clean, dry container. While stirring under slow agitation, add the total amount of solvent calculated based on the desired batch size. Stir slowly for approximately 10 minutes. Slowly add the curing agent to the stirring adhesive mixture. Stir for an additional 10 – 15 minutes. Cover the container to prevent additional solvent loss.

Application Method

• The recommended method of application for this adhesive mix is with a standard gravure roll coater.
• When using this type of conventional coating equipment, apply the adhesive at 30-45% TSC for best results.
• Depending upon the film or foil combination, and the end use of the lamination, apply approximately 1.5 – 2.5 lbs/ream (2.4-4.0 gm/m2 ) coating weight of adhesive.
• Deep draw applications often require higher coating weights to accommodate the package elongation.

Drying

• Optimum drying conditions are dependent on the specific machine speed, coating weight, dwell time, and efficiency of the dryer.
• A system with good air volume and exhaust is more effective than extremely high temperature to remove the solvents.
• The drying conditions should correlate to machine speed: Example: 50 – 60 °C (122-140°F) at 165 fpm, 60 – 80 °C (140-176°F) at 500 fpm. 
• Dryers with multiple zones should be staged from a lower temperature in the first zone to higher temperatures in successive zones.
• This will facilitate solvent removal without adhesive skinning.
• Extremely high temperatures and over-drying the adhesive can result in cure irregularities and lower performance.
• Caution should be taken to establish the optimum process conditions for your equipment.

Combining Nip

• The lamination of the primary and secondary substrates should exhibit excellent initial tack when combined at heated nip temperatures of 149-176°F (65-80°C).
• Pressure and temperature of the laminating nip may require adjustment based on the appearance, degree of wrap angle, dwell time, and thickness of the substrates.

Curing

• The laminate can be further processed, rewound and slit after 1-2 days of curing at room temperature.
• To achieve complete curing, i.e., total resistance to severe environments, allow 7-14 days of storage at room temperature.
• Cure rate may depend on film combination.

Equipment Clean Up

• Clean up of the application station is accomplished with solvents such as ethyl acetate, methyl ethyl ketone, acetone, or toluene.
• Protective gloves should be worn.