How to distinguish between good and bad colored tapes?
For colored tapes, it is convenient for marking and masking purposes, and generally there are more beige and khaki. A lot of people think that colored tape is the color of film, but in fact, the color is the color of glue. Squeeze the glue tightly and then pull it away quickly, so that the glue on one side can be pulled away, and the purity and transparency of the original film can be seen. The most important thing is to see the thickness of the glue. If no glue is pulled apart or pulled apart in dots, firstly, there are a lot of impurities in the glue, and the glue has no cohesive force. Second, there is too much water, which has evaporated. At this time, the initial adhesion of this tape has dropped sharply, and the hand feel can be distinguished.
Coat the object with yellow tape, and the better the covering property, the thicker the glue and the better the quality. Compared with the appearance of the adhesive tape, the adhesive tape is less, the color of the whole roll of doped adhesive tape is deep, and the transparency of the adhesive tape is high after opening. The color of the whole roll of good adhesive tape is not much different from the color of the one after opening, because the good adhesive tape has strong shielding property and there is no color superposition. Impurities should be coated on BOPP film by doped inferior adhesive tape, and only the backward direct gluing method is adopted. Therefore, there are often large impurity particles that are not completely dissolved, so the tape often has lines (where there is no glue) in use. Good adhesive tape adopts the method of soft tape transfer and gluing, and there is no line (ink leakage and less printing of printing tape are related to the printing machine).
Another way to distinguish is to look at the surface of the adhesive tape. When the adhesive tape has just been sliced into finished products, there are bubbles. After a week of storage, the bubbles will basically disperse. The surface of the adhesive tape with pure tincture glue is bright and clean without any white spots. The adhesive tape with impurities has many irregularly distributed white spots, which can't be dispersed by hand, and it is different from bubbles.
Ordinary sealing tape glue is acrylate glue, also known as pressure sensitive adhesive, and the main component is tincture fat. Tincture fat is a kind of polymer active substance, and the temperature has a certain influence on molecular activity. The tincture fat content of glue directly affects the use of adhesive tape. Many individuals think that adhesive tape with sticky hand feel is good for glue, which is actually wrong. There are two standards for the quality of adhesive tape glue in use, one is initial adhesion, the other is retention, and the two are inversely proportional. Generally speaking, adhesive tapes with adhesive force lower than No.10 are poorly coated with glue, generally only about 20 microns, such as stationery tapes and tapes for common promotion and binding. The initial adhesive force of normal sealing tape is between 15-20, and the thickness of this tape glue is generally 22-28 microns. Is the thickness that meets the standard. However, at present, most of the adhesive tapes on the market are mixed with impurities, so the thickness is increased. In order to cover the impurities, the glue is also mixed with toner, so the transparent adhesive tapes are egg yellow and light green, which are generally inferior.
To sum up, everyone can basically judge whether the tape is good or bad from the appearance. Another important condition to distinguish whether the tape is good or bad is not to feel the viscosity only by the hand feeling, because the initial adhesion of doped tape is very high when it is not volatilized, so it is necessary to paste the object with tape and then quickly pull it apart to see the retention force. After repeated pasting several times and touching it with your hands, it is obvious that the tackiness will drop. Doped adhesive tape is usually dissolved with gasoline and acid when making glue formula, so the smell is very strong. Regular large enterprises are dissolved with toluene, which has been volatilized by the fan during the coating process.