How to test the acid, alkali, water and solvent resistance of ink by soaking method

soaking method. This method is to soak the dried ink scraping sample in the selected acid, alkali and other solutions, take it out after a certain period of time, compare the ink scraping sample and the change degree of the solution before and after soaking, and then evaluate according to the specified rating method its resistance.

(1) Equipment and materials

①Apparatus.

(i) Minor Ink Knife.

(ii) scraping (ink) knife.

(iii) Test tubes.

(iv) Small tweezers.

② material.

(i) Scratch paper.

(ii) Selected acid, alkali and other solutions.

(2) method

Scratch a sample according to the determination of color, but do not leave a part of the thick ink layer, and let it dry at room temperature.

Cut the ink scraping sample into a small strip with a width of about 1.5 cm and a length of about 10 cm, put it into a test tube filled with acid, alkali and other solutions to soak (the test tube should contain a solution half the length of the test tube), and make the oil Half of the scraper was submerged in the solution.

After soaking for 24 hours, take out the ink scraping sample with tweezers, rinse the scraping sample with distilled water to neutral (no need to rinse for water resistance and solvent resistance test), dry it at room temperature, and check the degree of change of the ink scraping sample (that is, immersion the difference between the part and the unsoaked part) and the degree of staining of the solution.

According to the degree of change of the ink scraping sample and the degree of dyeing of the solution, the grades are rated according to the regulations listed in Table 27-4.

(3) Precautions

Table 27-4

① The drying degree of the ink scraping sample has an impact on the test results. A wet scratch-off sample may have the disadvantage of floating the ink after being soaked in liquid.

②Among the grades, grade 5 is the best and grade 1 is the worst. When rating, if the degree of dyeing of the solution does not match the degree of change of the ink scraping sample, use the worse of the two to rate it.

③ The change of scratch paper should also be considered, which can be verified by doing a blank test.

④ The temperature during measurement can generally be between 20-35°C.

⑤ When measuring the acid resistance of ink, use 1% hydrochloric acid solution. When measuring the alkali resistance of ink, use 1% sodium hydroxide solution. Water resistance was measured using distilled water. Solvent resistance is mainly determined by ethanol. Of course, different solvents can be selected according to actual needs.

The comments in Table 27-4 are very loose, so the Testers need to have a lot of experience.

The following is an introduction to the commonly used rating standards in the world, which will help us do a good job of rating.

This standard is called "Color Fastness Staining Sample Card".

"Dyeing Fastness Staining Sample Card" is a standard used to evaluate the staining degree of standard table-colored textiles in the dyeing fastness test of textiles. It is composed of five standard samples with increasing depths from white to gray and similar white Five pairs of standard sample cards for comparison, each pair representing a staining grade. Level 5 is better, which means no staining,

Therefore, the pair of level 5 is actually composed of a pair of identical white standard samples, and the color difference between them is equal to zero. The reflectance of the white standard sample used here should be greater than 85%. Level 1 is the worst, indicating the most serious staining. The color difference between the five standards in increasing shades of white to gray and the white standard is specified. The color difference is measured with a Spectrophotometer and calculated with the ANLAB color difference formula, and each pair of standard sample cards should meet the requirements in Table 27~5.

When using this set of "Dyeing Fastness Staining Sample Cards", in order to avoid the illusion of legs and eyes due to the different positions of the tested samples and the sample cards, this set of standards also has several pairs arranged according to the specified positions. Attached card for round hole. When comparing, a pair of gray and white in the five-level standard sample is placed in a pair of round holes in the upper part of the attached card, and the stained and unstained samples are placed in a pair of round holes in the lower part. Replace the 5-level standard sample until the staining degree of the tested sample is equivalent, the grade of the standard sample is the staining level of the tested sample. If the staining degree of the tested sample is between two levels, it can be rated as an intermediate level and written as level 1-2, etc., which means that it is worse than level 1 or level 2. The comparative observation should be carried out under the light of the northern half of the day. If other light sources are used, the illuminance should be no less than 540 lux. The angle of light projected on the sample card is about 45 degrees, and the line of sight should be close to the plane of the sample card. at vertical.