Test the dryness of ink by pressure friction method

Pressure rubbing method, this method is suitable for dry inspection of inks that are mainly osmotic drying. Rotary (news) inks, lead printing (printing) inks, and transcription inks can all be determined by this method.

(1) Equipment and materials

①Apparatus.

( i) One 10-gram weight.

(ii) A square glass piece weighing 2±0.15 grams. The glass sheet has a side length of 20 mm and a thickness of about 2 mm.

( iii) Minor Ink Knife.

(iv) scraping (ink) knife.

(v) Chronographs.

(vi) A glass plate, the size of which can hold the newsprint used for the test.

② material. No. 1 newsprint, cut to approximately 15 x 11 cm.

(2) method

Use a small ink knife to take a small amount of the special test ink and place it on the newsprint, and use a scraper to scrape the ink into a thin layer from top to bottom. The thin layer of ink is about 4-5 cm wide and about 10 cm long.

Record the scraping time of the scraping sample. After 15 minutes, put the scraping paper flat on the glass plate (the ink layer is up), cover it with a piece of blank newsprint, and put a square piece of glass on the blank newsprint. , so that all the glass sheets are pressed on the -end of the scraping sample through blank newsprint, and the - side of the glass sheet is close to the edge of the scraping sample, and then add a weight on the square glass sheet.

Quickly grab the other end of the blank newsprint and move along the parallel direction to the edge of the scraping sample, so that the blank newsprint rubs against the scraping sample under the pressure of the glass sheet and the weight.

Remove the weight and the glass piece, and check whether the blank newsprint is stained. If it is discolored, repeat the above test with new newsprint at regular intervals until the blank newsprint is not stained.

The drying time of the sample ink is the time required from the time the scraping sample is scraped until it is empty from the newsprint without staining.

(3) Precautions

①The measurement should be carried out under the condition of constant temperature and humidity, the temperature is 25°C-1°C. The relative humidity is 65%±5%. The paper used for the measurement should be stored under this condition for more than 24 hours in advance.

② This determination also requires rich experience, for example, the speed of movement has a great influence on rubbing staining.

③ The time interval for repeating the test shall be determined by the experience of the Tester.