Henkel Lite-Lok 491

Surface Preparation

LITE-LOK 491 bonds well to many untreated surfaces. However, adhesion is often improved by surface preparation before bonding. The surface should be free of contamination such as dirt, dust, grease or oil. An alcohol wipe is suitable for cleaning most surfaces. Optimum strength is obtained by abrading the surface followed by a solvent wipe to remove any loose particles. Polyolefins must be corona treated, or flame treated before bonding.

Application

LITE-LOK 491 is best applied by extruding the product onto the substrate to be sealed or bonded. Sufficient product must be applied to seal all gaps, and completely coat the part to be bonded or sealed. After dispensing onto the part, the product should be cured as soon as possible to prevent any pre-reaction with ambient light.

LITE-LOK 491 may be applied via a pressure pot, or piston pump dispensing system. All fittings and tubing used in the dispensing system must be opaque to light. If the product is transferred from a large container to a smaller hand held dispensing bottle, that bottle must be light impenetrable. (see Storage & Handling).

Curing

Optimum cure is obtained when LITE-LOK 491 is exposed to high intensity visible light or long wavelength UV light. The peak reactivity of the product is from exposure to light from 385 nm through 420 nm. The time needed for curing is a combination of many factors. Some of these are: ? The thicker the substrate, the longer the exposure time needed for curing.

The more UV light absorbing that the substrate is, the longer the exposure time needed for curing. The lower that the intensity of the UV light source is, the longer the exposure time needed for curing. The farther the distance of the product from the UV light source the longer the exposure time needed for curing.

Typically, LITE-LOK 491 will cure after a UV light exposure from two to five seconds, when cured at or near the focal point of a high intensity light source. To achieve complete cure, all of the adhesive must be exposed to the UV light source.

LITE-LOK 491 is designed for use as a <0.040 inch coating. LITE-LOK 491 cures best when cured between two substrates as an adhesive. Excess exposed product may exhibit a slight surface tack.

Clean-Up

Unreacted material can be cleaned up using acetone. If skin contact occurs, the affected area should be washed thoroughly with soap and water. Eye protection against UV light should be worn whenever the product is being used. Eye contact should be treated by thoroughly washing with water followed by medical attention. Aprons should also be used. Adequate ventilation is necessary to prevent inhalation of vapors.