Evaluation of Ink Drying Speed / FTIR

IRTracer-100 Rapid Scan Functionality (20 times/sec) Helps to Enhance the Value of Inks

In the offset printing industry, the demand for small lots of various types of printing with shorter lead times has increased. However, it is difficult to deliver printed products in a shorter time because it takes time to make the proof and wait for inks to dry. For example, in duplex printing, materials printed on one face need to be left for several hours or overnight before printing on the other face in order to prevent offset. In other words, shortening the ink drying time (fast drying printing technology) is an important factor toward achieve shorter lead times.
Because they dry fast, UV inks (UV curable inks) are now used more frequently. UV inks have the ability to start hardening immediately. However, the difference in hardening speed according to colors (pigments), and temperature-dependent viscosity and adhesiveness have been problems.
The IRTracer-100 can measure the hardening processes of UV inks and drying processes of solvents contained in inks and output the results on infrared spectra so that the drying speed can be evaluated simply but with high accuracy.

In this example, drying speed was evaluated using ink of a fiber marker pen as a sample. High-speed monitoring was performed via rapid scanning using a single-reflection ATR accessory. Immediately after the ink was applied to the ATR prism, the peak of the solvent started to rise. As the solvent evaporated, the peak gradually decreased. Since the solvent evaporated instantaneously, measurement using the rapid scan feature was effective.

Changes in spectra for solvent components were compared for three different color marker pens from different manufacturers. The results below show how the solvent drying time is successively longer for Markers A, B, and C.

FTIR

Fourier Transform Infrared Spectrophotometer

FTIR is useful for conducting analysis of molecular structure, and LabsolutionsIR software, with its included timecourse measurement program, permits tracking of sample peak changes over time.
Although the program is suitable for tracking a gradual reaction, the included Rapid Scan feature is effective in cases where the sample reaction is completed within a few seconds.