C-91 Monocat is a single-package screen ink formulated specifically for use on pre-treated polyethylene and polypropylene containers.  Monocat has excellent gloss, flexibility, screen stability, and product resistance. When using a 255 mesh screen, one gallon of C-91 will cover approximately 1200 square feet. Typically 255-305 mesh is used. This series is available in quarts and gallons only.

Substrates;

C-91 is especially recommended for use on pre-treated polyethylene and polypropylene containers, but may also be used on some metal surfaces for its toughness and solvent resistance.  C91 Monocat is not suitable for outdoor use. Resistance Properties; When fully cured, C-91 is resistant to most household and cosmetic products, detergents, motor oils, and common solvents.  C-91 Monocat is not resistant to bleach.

Drying;

C-91 dries by solvent evaporation, followed by chemical curing.  Prints will be tack-free and able to be handled after approximately 1-2 minutes at 175 F however, prints will not be fully cured or product resistant at this stage.  Full chemical curing and product resistance requires either an additional 4-5 minutes at 175 F or 5-7 days air drying at ambient temperature or an equivalent schedule combining elevated temperture with subsequent air drying.

Substrate Pre-Treatment;

It is essential that polyethylene or polypropylene substrates  are pre-treated before printing.  These substrates are chemically inert and have a very low surface tension.  Only by "activating" the surface can adhesion of any coating be achieved.  Pre-treatment of polyethylene or polypropylene containers is usually accomplished by briefly exposing (1-second) the surface to a flame, preferably immediately prior to printing.  Pre-treatment of polyethylene or polypropylene surfaces may be assessed by their degree of wetting with calibrated surface-tension solutions.  For best results, a surface tension in excess of 46 dynes/cm is recommended.

Modification;

For best results, C-91 may be reduced with 10-20% by weight of ST-291 Reducer.  For exceptionally fine detail printing, or under adverse ambient conditions, either ET-12 Retarder or GEL-100 Gelled Retarder may be substituted for all or part of the reducer.  The restricted flow of GEL-100 allows better print defination, particulary for reverse detail or 4-color process printing. Note; The use of ET-12 Retarder or GEL-100 Gelled Retarder may decrease drying speed, ensure that drying is adequate before commencing a full production run.  For accelerated curing, 2-5% by weight of ST-260 Cure Accelerator may be added to C-91.  Excessive addition will adversely affect final resistance properties.