Products: Chemicals: Reactive Cross Linking Fountain Solution (RCL)

R-C-L™ (Reactive Cross-Linking) fountain solution concentrate is a patented formulation and a radically new chemical composition designed specifically for the offset printing process.

RCL's chemical formulation is made up of a blend of ingredients, some familiar, others entirely new. RCL incorporates Sudanese gum arabic as its base. This natural ingredient, the finest available, has been used in fountain solutions for decades. Sudanese gum arabic allows the press operator to use a minimum amount of moisture and maintain excellent color fidelity of the ink. The base mixture is compatible with metal, silver and polyester plates. The key ingredient is a new catalyst developed specifically to induce cross-linking between the ink and paper.

RCL infuses the ink with reactive qualities and causes it to cross-link when the printed substrate is exposed to ambient temperature, and increases rapidly when exposed to infra-red/ultra-violet radiation or high velocity hot air in lithographic printing operations. The cross inking action on the surface of the ink is instantaneous and forms a barrier which inhibits the transfer or offsetting of the ink, even while the ink is still wet.

Continued cross-linking action causes the ink to set up and dry at a much faster rate than with ordinary fountain solutions, resulting in reduced dot gain and sharper print definition. This unique blend of wetting agents reduces or eliminates the need for isopropyl alcohol, thereby reducing V.O.C. emissions in the pressroom. The advent of RCL establishes a new approach to solving lithographic issues. Among these are ink setting, ink drying, ink and water balance, ink set-off, dot gain and environmental compliance.

A catalyst is a substance that alters and increases the rate at which a chemical reaction takes place. The desired chemical reaction needed in offset lithography is the bonding of ink to paper. It is the inclusion of the patented catalyst that gives RCL its unique ability to cross-link the ink to the paper.

Cross-linking is a chemical reaction that causes bonding at the molecular level. The catalyst in RCL causes a "chain reaction" that chemically links the ink molecules to each other, and forms a barrier, which inhibits the transfer or offsetting of the ink even though the ink is still wet. The action is instantaneous. Continued cross linking action causes the ink to set up and dry at a much faster rate than with ordinary fountain solutions, resulting in •reduced dot gain and sharper print definition. While no additional drying apparatus is needed, RCL sharply increases its cross-linking effectiveness with stimulus from IR or UV dryers.

1. Drain and clean the dampening system, change filters if used
2. Refill with fresh water
3. Add 3 to 5 ounces of RCL per gallon of water
4. Do not add any other chemicals
5. RCL is buffered to maintain a pH of 3.7 to 3.8 and 1400 µmoh's

1. Turn the spray powder unit off for the first fifty sheets
2. Set the spray powder dial at 1/2 for the next fifty sheets
3. Increase settings by 1/2 per fifty sheets until reaching a setting of 2
4. Turn the powder to the normal setting for the rest of the pile. This procedure is effective to determine the optimum spray powder setting for continuous running.

RCL contains anti-foam agents, which allows it to be used in recirculating fountain systems. RCL is formulated to be used without adding alcohol in dampening systems with soft metering and form rollers (18-22 durometer) and where the proper roller settings have been made. Alcohol may be added for dampening systems that require decreased surface tension without adversely affecting RCL's performance.

While no infra-red or ultraviolet dryers are necessary to achieve faster drying results, IR or UV combined with air knives increase, the cross linking action in inks on high pile delivery presses. Hot air dryers have proven to be most effective on low pile delivery presses.

Good results are achieved with pile temperatures of 90-95°F, while optimum results are achieved at temperatures of 100-100°F.