(good-grade, controlled acid-value, good-melting range) is generally cooked in ARLO (alkali refined linseed oil), maintaining some ratio ( like 50:50, 60:40….) to get the required properties of the general off-set Ink ( four coloured /process), which are widely used for printing on duplex-board, board, books, news-paper, magazine and others.
If some part of Phenolic-Resin is replaced by petroleum, hydrocarbon-resin (trade name is PETREZ, selected grade ) like 10 to 12 percent, the results achieved are:
- Tack of the Ink will be controlled.
- No effect in gloss.
- No effect in Ink-body (Printing viscosity).
- No effect in litho-resistance.
- No effect in Pigment-Resin chemistry as the, acid-value of PETREZ is almost zero.
- Brings down the Ink-Cost ( which is important for any manufacturer)
So there is no hard and fast rule, in selection of Raw-Materials to formulate the Inks.
Formulation is the unique word, in every step of every moment in life. Formulation provides some guide, shows the way to any manufacturer. But we modify it, formulate it accordingly. To formulate or before formulating, the following points must be cleared.
- Why to do!
- What to do!
- How to do!
If the above three points are clear, then Formulating of Formulation is easier. So every ink-maker is never sticky in formulation. But must be careful in picking the right raw-material. Every day new products arrive in the market and many disappear also from the market. Ink makers are also searching to pick, to select the right one.
It is well known to all liquid-ink makers, that one of the main raw-materials was VAGH (vinyl-ter-polymer) for making reverse, lamination Ink on polyester surface. This VAGH was the unique choice for liquid-ink makers, and most of the ink-makers never thought to replace, even to look at its alternatives, because of its exceptional chemical properties. But “nothing is permanent”.
SOLBIN-A, arrived in market, and also disappeared from market. Now there are so many, vinyl-ter- polymers are roaming in supplier's wares and the ink-makers are selecting their right one.
But all of these vinyl-ter-polymers are not good enough as VAGH, SOLBIN-A, as far as their chemical properties, like stability, viscosity, bonding ( adhesion on substrate) and others. So manufacturers are some times confused but if the above three points are clear, Formulating their existing Formulation it is never hard, to make any product and to fulfill the customer's need.
Here is another Idea that can be discussed. We all know the use, need and application of Over-Print Varnish (for post-press-application, where the printing substrates are mainly paper, board). Now the trend is on U-V Cured varnish. It is a very good product in all ways, but it is costlier. It can be alternated by resin–plasticizer combination, without effecting the properties, which we are getting now from the U-V-Cured varnish. But comparing the cost, it is cheaper than U-V-Cured varnish. And interestingly it will save the cost of installation of the U-V-curing system.
Desired effects needed for over-print-varnish:-
- Zero-tack/ very good solvent releasing (after complete dry).
- Moderate scuff-proof (which is provided by U-V-cured varnish).
- Very low moisture absorbing (to resist set/off).
This over-print-varnish can be applied by Roller-Coating, Gravure and Screen system.
Challenge and Innovation are two sides of same coin. Thus there is o way to ignore or deny and it is better to accept it, face it. And this why, we are always Formulating the Formulations.
This article is written from experiences only, no references are added.
Apurba Krishna Das