Water-based plastic woven bag ink characteristics

The ink properties mainly include pigment hue, fineness, coloring power, fluidity, gloss, viscosity, drying speed, adhesion fastness, storage stability and the like. Here's a comparison of its main performance indicators:

Performance index Alcohol-soluble plastic Woven Bag ink Water-based plastic woven bag Ink hue Approximate standard Approximate sample fineness ≤ 5 ≤ 10
Coloring power 110% 100%
Good fluidity Better shine 50% 55%
Viscosity≤60 ≤60
Drying speed 20 to 60 (mm/30s) 30 to 60 (mm/30s)
Adhesion fastness Rubbing 10 times No rubbing and rubbing 10 times No fading stable Storage stability Good environmental protection Environmental protection

Below are some important indicators to discuss

1, Hue

Contrast to scratch color as the test of ink color, gloss, and coverage rate is the conclusion that the sample and the standard sample are compared in parallel. The scraping method can be used to determine the hue, gloss and hiding rate of the ink from the appearance of the ink, and the uniformity of the ink dispersion can also be determined. Because the pigment is not interfered by the solvent, the hue of the water-based plastic woven bag ink is brighter than that of the alcohol-soluble woven bag ink, and the color is not easily transferred, which is more conducive to the design and printing of the outer package of the product.

Fineness

The thickness of the so-called water-based plastic woven bag ink refers to the degree to which the solid powdery substance such as pigments and fillers mixed in the binder is dispersed. Fineness is also an important quality indicator because it is not only related to the application properties of the ink (including tinting power, hue, stability, etc.), but also related to the rheological properties of the ink.

Too coarse particles can cause defects such as heaping ink and stencils, and the coloring power and hue of the inks will also be poor. If the particles are too fine, they will have high fluidity and will flow after printing. This kind of flow will lead to the expansion of dots and influence. Print quality. In addition, the thickness of the ink also affects its dispersibility. When the dispersibility of the ink is not satisfactory, its printing performance is also unsatisfactory, manifesting that the printed surface is not smooth, smooth and soft, and it will produce a "block"-like feeling, thus greatly reducing the printing effect.

Water-based plastic woven bag inks and alcohol-soluble inks can easily reach the fineness required for printing in the grinding process, but the water-based ones are more conducive to the production of operators because no harmful gases are spilled during the grinding process. , Make manufacturing more convenient and convenient. The alcohol-soluble woven bag ink will have a large amount of organic solvent volatilization during the production process, causing the production workers to have an unpleasant feeling. Therefore, the comparison of fineness is also an expression of the entire formula design.

2, coloring power and fluidity

Coloring power and fluidity are generally observed by the naked eye. Comparison of tinting forces is done under standard light sources. The degree of fluidity is usually the degree of sluggishness of the ink flowing into the container with the ink adjuster. Since the resin used for water-based inks is not very affected by temperature, it is much better than alcohol-based plastic woven bag inks based on polyamide. The former does not need to worry about condensation in the winter to ensure the printing performance of the ink, so that its coloring power and fluidity can reach the technical indicators required by the printing press. Therefore, water is more practical than alcohol-soluble ink.

3, gloss

With the judgment of the hue, a gloss meter is used for the measurement to observe the importance of the angle and the gloss. The printed surface of water-based plastic woven bag ink has strong abrasion resistance, the film glossiness is ≥45%, and it has no influence on the color of the printed matter. The printed material is not easily yellowed under long-term intense sunlight irradiation. However, the gloss of water-based plastic woven bag inks cannot be completely compared with that of alcohol-soluble inks. Therefore, ink printers will continue to work hard to discuss this issue.

4, viscosity

Viscosity is the most important control indicator in ink applications because it directly affects the ink transfer transfer performance and the quality of flexographic prints. The viscosity is related to the type and particle size of the colorant, in addition to the viscosity and density of the resin in the binder.

In printing, the low viscosity of the ink transfers quickly, resulting in defects such as light color, large dot gain, high light dot distortion, uneven ink transfer, etc.; high viscosity and slow ink transfer will affect the transfer performance of the anilox roll, resulting in ink Inconsistent colors, sometimes dark prints, and dirty, dirty version, and other ills.

In addition, in the printing process, the temperature has a greater impact on the viscosity of the ink, usually the temperature increases the viscosity decreases, otherwise, the viscosity increases. Therefore, in the printing process, in order to maintain the consistency of the print density, the temperature of the printing shop should be kept constant. Water-based and alcohol-soluble plastic woven bag inks all require the same viscosity, so they will not be described in detail here.

5, drying speed

Water-based and alcohol-soluble plastic woven bag inks are not the same due to the drying mechanism and are discussed separately here. Water-based ink drying is a very important technical indicator. In addition to its own performance, the drying speed of water-based inks is related to the printing speed, the drying capacity of the drying equipment, and the properties of the printing materials.

The process is completed in two stages: the aqueous ink changes from a liquid to a semi-solid state, and no longer can be transferred. The initial drying is indicated by the initial drying; the main part of the binder in the semi-solid aqueous ink undergoes a physical or chemical reaction. Solid film formation is the thorough drying stage of water-based inks and is indicated by thoroughness. The fixation stage and thorough drying stage of aqueous ink are collectively referred to as fixation drying.

The drying of the alcohol-soluble ink is mainly accomplished by evaporation drying to complete the film formation process. Under the condition of solvent determination, choosing different kinds of resins will also affect the drying properties of the ink. Because the curing speeds of different resins on substrates are different, and the release characteristics of solvents are also different, the drying properties of inks are also different. Conversely, when the resin is determined, the choice of different solvents is not the same as the drying speed. In practical applications, a quick-drying agent or slow-drying agent may be added to the ink according to the actual printing speed, and the drying speed of the ink may be appropriately changed to obtain a stable printing effect.

6, attachment fastness

After the plastic film is printed, the ink must be firm, otherwise it will lose its use value. Simple test method for rubbing: rub each other against the printing surface several times to see if the ink layer is rubbed off. The fastness of the water-based and alcohol-soluble plastic woven bag inks is currently recognized by the market. With the continuous updating of raw materials, the fastness of the water-based woven bag inks will be better.

Characteristics of water-based plastic woven bag ink: The biggest feature of water-based plastic woven bag ink is to reduce the emission of VOC (organic volatiles) into the atmosphere, thus preventing air pollution, improving the printing operating environment, and greatly reducing the fire hazard.

It can completely eliminate the harmful effects of certain toxic substances in solvent-based inks on the human body and the pollution of packaged goods, and improve the overall environmental quality. It is particularly suitable for packaging and printing products that require strict sanitary conditions such as foods and medicines. In developed countries such as Europe, America and Japan, water-based plastic woven bag inks have gradually replaced solvent inks.