Overview
In areas such as packaging printing, electronic product labeling, and consumer product labeling, ink coatings often need to be exposed to alcohol-containing cleaners or solvents. Evaluating the alcohol resistance of inks is crucial to ensure the durability and appearance integrity of prints during use. The ink solvent resistant wiper can quantitatively evaluate the ability of the ink layer to resist alcohol wiping by simulating the mechanical wiping action and combining it with standard solvents. This testing method widely refers to domestic and foreign standards, such as ASTM D5402 and GB/T 13217.7, to provide an objective basis for quality control.
Detection principle
Ink solvent resistant wipers usually consist of a fixed platform, a reciprocating motion mechanism, a standard wiping head and a pressure control system. The core principle is to fix a cotton cloth impregnated with a specific concentration of alcohol on the wiping head, and wipe the surface of the ink sample repeatedly under the set pressure, speed and stroke. The anti-alcohol properties of the ink layer were evaluated by observing whether the ink layer dissolved, peeled off, changed color, or whether the wipe was stained. The instrument allows for precise control of experimental parameters, ensuring reproducibility of results. The relationship between the number of wipes and the degree of ink damage can be preliminarily described by the following formula:
N = k × (F/v) × (1/σ)
Among them, N is the number of wipes to failure, k is the constant related to the ink material, F is the wiping pressure, v is the wiping speed, and σ is the resistance of the ink layer to alcohol.
Testing process
The testing process strictly follows standard steps. First, the ink sample is prepared on a standard substrate and fully cured. Select a specified concentration of ethanol solution (such as 95% ethanol or isopropyl alcohol) as the test solvent. Set the wiper parameters to standard conditions, such as the pressure is often set to 500±50 g, the wiping stroke is 100 mm, and the speed is about 30 times/minute. After starting the test, stop the sample surface and wipe every certain number of times (e.g., 10 times) until a predefined failure endpoint (e.g., exposed bottom, visible staining) occurs. The number of wipes at this time is recorded as an evaluation index.
Influencing factors
The test results of ink alcohol resistance are affected by multiple factors. It mainly includes the chemical structure, cross-linking density, pigment dispersion stability of the ink resin system, and curing process (such as UV curing energy, thermal curing temperature and time). The adsorption and surface energy of the substrate can also affect the results. In terms of instruments, the wiping pressure, speed, solvent replenishment frequency and ambient temperature and humidity need to be strictly controlled. For systematic evaluation, the main variables can be summarized as follows:
| Ink material factors | Resin type, pigment concentration, additives |
| Process curing factors | Curing method, energy or time, curing degree |
| Instrument operating factors | pressure, speed, solvent concentration, wiping head material |
| Environmental and substrate factors | temperature and humidity, surface tension of the substrate, porosity |
Evaluation of results
Inspection results are typically expressed as a specific number of "pass/fail" requirements, or the exact number of wipes recorded to failure. A high wipe count indicates that the ink has good alcohol resistance, which helps ensure that the print remains clearly marked during subsequent processing (e.g., alcohol wipe cleaning) or end-use. This test provides key data support for ink formulation development, production process optimization, and terminal application selection, helping to improve product reliability in harsh environments.
References
ASTM D5402-19, Standard Practice for Assessing the Solvent Resistance of Organic Coatings Using Solvent Rubs.
GB/T 13217.7-2009, Test method for liquid ink for determination of ethanol resistance.
Printing Technology Ink Resistance Test Method General Principles, Industry Technical Reports.