How to Evaluate NEOPTSA in Polyamide-Based Packaging Ink Systems
NEOPTSA, short for N-Ethyl O/P Toluene Sulfonamide, is a sulfonamide plasticizer commonly evaluated in solvent-based ink systems where flexibility and film performance need to be adjusted.
For packaging ink manufacturers, one of the most relevant areas is polyamide-based gravure and flexographic inks.
The important point is that NEOPTSA should not be selected only by looking at a TDS or asking for a standard dosage.
Its performance depends on the whole formulation.
Why NEOPTSA Is Used in Packaging Ink Formulations
In a polyamide-based packaging ink, the dried ink film needs to maintain a balance between several properties:
• flexibility
• adhesion
• folding resistance
• film integrity
• drying behavior
If the film becomes too rigid after drying, problems may appear during bending, folding, lamination or converting.
In suitable formulations, NEOPTSA can be evaluated as part of the plasticizer package to improve flexibility and reduce excessive brittleness.
However, not every ink problem should be solved by adding more plasticizer.
Resin selection, solvent balance, substrate type and printing conditions can also affect the final result.
What Should Be Checked Before Testing NEOPTSA?
Before starting a trial, it is useful to understand the existing ink system.
The most important information usually includes:
| Resin system | What type of polyamide resin is being used? |
| Current plasticizer | Is another plasticizer already part of the formulation? |
| Substrate | Is the ink being printed on BOPP, OPP, CPP, PE, PET or another film? |
| Printing process | Gravure, flexographic, surface printing or reverse printing? |
| Target improvement | Is the goal better flexibility, folding resistance, adhesion or film integrity? |
These questions are often more useful than asking directly, “How much NEOPTSA should I add?”
A Practical Way to Start the Trial
For the first evaluation, it is normally better to keep the base formulation as stable as possible.
Keep the resin, pigment and solvent system unchanged, then adjust only the plasticizer package.
If the formulation already contains another plasticizer, a partial replacement trial can often give a clearer comparison than simply adding more plasticizer to the existing system.
After printing and drying, the following points should be checked:
• film flexibility
• adhesion
• folding resistance
• drying behavior
• surface feel
• final film appearance
The objective is not to use the highest possible NEOPTSA level.
The objective is to find the level that gives the required improvement without negatively affecting the rest of the ink system.
From Laboratory Trial to Production
A successful laboratory result is only the first step.
During production printing, performance can also be influenced by:
• printing speed
• ink viscosity
• solvent evaporation
• drying temperature
• substrate treatment
• lamination or converting conditions
For this reason, NEOPTSA should ultimately be evaluated under conditions close to the customer’s actual production process.
NEOPTSA Application Support from HANGHUI
At HANGHUI, we focus not only on supplying NEOPTSA, but also on helping customers evaluate whether it is suitable for their formulation.
For a useful technical discussion, customers normally only need to provide basic information such as:
resin type + current plasticizer + substrate + printing process + target improvement
From there, a practical trial plan can be discussed.
If you are currently using NEOPTSA, looking for an alternative supplier, or evaluating it for a new polyamide-based packaging ink system, we are happy to support sample testing and application discussion.
