We summarized the film ink test methods in the laboratory into the following 10 items, namely ink adhesion test, initial drying length test, fineness test, viscosity test, color density test, pH stability test, ink film ink resistance and scratch resistance Wipe test, solvent content test, ink film shrinkage performance test and surface tension test. The order is as follows.
1. Adhesion
First of all, we must figure out how to detect adhesion and how to determine it. Enterprises that have used solvent-based inks for a long time must know that they use tape to test, and high-end companies even know that they must use 3M600 / 610 test tape to test. why? This is because the adhesive force of the glue of the 3M600 / 610 tape to the ink film is compared with the adhesion of the ink film to the film. The adhesion of the glue is less than the adhesion of the ink film, and the adhesion is up to the standard, otherwise it is not up to the standard. The basis is to see if there is ink or how much ink is stuck on the tape. Therefore, the adhesive force of glue is a measurement index and a very important parameter. Not all scotch tape glue can be used as a judgment standard, the internationally accepted standard is 3M600 / 610. There are two possibilities for adhesion failure. One is that the ink and the film are incompatible on the resin, and there is no adhesion. The other is that although it has adhesion, the ink film is too tender to withstand the tearing of the tape. There are two important factors in the compatibility of inks and films on resins. The first is solubility matching, and the second is wettability matching. There are also two factors for the ink film to be too tender. That is, the molecular weight of the ink resin is not enough, so the ink film is not strong enough, or the ink film is not dry enough, so the residual solvent content is high, and the residual moisture in the ink is high.
The key to ink adhesion on the film in water-based ink is water-based emulsion. Whether water-based ink can be adhered to depends on whether the water-based emulsion is properly selected and whether the ink is dry after forming the ink film. Since the materials used for film gravure are generally divided into two types, there are differences between polar films and non-polar films. When choosing a suitable thin film gravure ink, it is not necessary to demand the compatibility of an emulsion to different films in the early stage. It can also be used exclusively, but it must be reliable.
In the judgment of adhesion, the requirement of the No. 1 screw is actually the requirement of the thickness of the ink layer. In order to dry thoroughly, the thinner the ink layer is better, if there is a No. 0, it is better. Drying conditions are important for adhesion. Drying conditions, drying time, and whether they need to be matured or matured are all factors that are considered in consideration of the characteristics of the aqueous emulsion resin. Under the condition that the solubility parameter of the aqueous emulsion cannot be confirmed, it takes time to help judge, and the waiting time of one week or even two weeks. Dragging the judgment time so long is to eliminate the factors of imperviousness and focus on judging the compatibility of the water-based resin and the film. Do not judge one-sidedly, and easily veto ink or ink that still has defects, which may mean giving up opportunities.
2. Primary stem length
The initial drying length is an effective characterization of the drying performance of volatile inks. Its definition and related data are actually for solvent-based inks. The characteristics of the inking mechanism of the gravure press are actually for solvent-based inks, but because we are suitable for solvent-based inks. gravure printing inks, the print quality is consistent with solvent-based inks, solvent-based inks and therefore with the idea early to evaluate coherence length is feasible, but have different parameters. According to the provisions of GB / T 13217.5-2008 "Liquid Ink Initial Dryness Test Method": the initial dry length is measured using a scraper fineness gauge with a depth of 0-100 μm; the ink is transferred to the printing material in 30 seconds, and then the length is measured. The inking structure of the existing gravure printing machine, the conventional value of using solvent-based ink is about 10 ~ 60mm (25 ℃, 30 seconds). It is worth noting that the ink desiccant technology and resin Tg technology cannot be simulated with the initial drying length, which involves some new technologies of ink. In expressing the general technique of ink painting, it is necessary to leave the necessary mouth for effective new technologies in the future.
3. Fineness
Pay attention to the fineness of ink, generally measured with a scraper fineness meter, but the particle size of ink is relatively small and can be ignored under normal circumstances. In fact, the finer the ink is, the better the fineness. For high-intensity inks, pay attention to the following two issues: whether dyes and water-soluble resins with good dispersibility but low molecular weight are used. Generally, dyes are added to the pigment system of cheap ink. In addition, too thin dyes will bring some difficulties to the treatment of water and ink wastewater, and the inks of too fine pigment system indicate that the molecular weight of the aqueous solution resin is low, and you must be vigilant when selecting gravure inks. At the same time, for gravure ink, also pay attention to the molecular weight of the water-soluble resin that constitutes the color paste and the emulsion resin that constitutes the film-forming resin. If the difference between the two is too large, the ink particles will re-agglomerate, thereby forming the risk of gravure knife wire .
4. Viscosity
Viscosity must be determined within a reasonable pH range. The highest goal is that the opening viscosity is basically the same as the use viscosity. It is wrong to think that the higher the viscosity of the open barrel, the more water can be added to adjust the printing viscosity, thereby reducing the cost of ink. The viscosity of the ink must be determined by the characteristics of the inking unit and gravure of the gravure printing machine. It is not scientific to require all inks to have a low viscosity.
5. Color density
Usually used The X-Rite spectrodensitometer measures the color density. The ink storage capacity of the No. 2 wire rod of gravure printing is almost the same as the ink storage capacity of the traditional electrogravure gravure. According to the data of the densitometer, the difference of the pigment ratio of the same color solvent-based ink can be determined. Color density measurement can determine whether the price of ink is basically reasonable, because of the cost of ink, the cost of pigment is the highest. In addition, when the process must use a light version, it must be predicted how much the color density will change after the version depth drops significantly.
Search the selection of banquet chairs at Concentric to find designs suitable for any gathering and venue. A practical choice for party rental companies, event venues, or for regular use in your home, these Folding Chairs with metal frames are built to last. A molded seat provides comfort to guests while the heavy-duty frame supports up to 330 lbs. The textured seat ensures safe and comfortable seating. After use, place them on top of each other or in a row.
Banquet Chairs,Restaurant Banquet Chairs,Banquet Tables And Chairs,Banquet Style Chairs
jiangsu concentric internatinal ltd , https://www.jsconcentriccorps.com