Details of Products:
pouch bags for food
MOPP/Kraft paper/VMPET/PE -- 0.20mm
Sealing & Handle:
Some problems that should be paid attention to in the printing process of kraft packaging bags:
Pay attention to printing color.In order to get better color reproduction in kraft printing, it is more difficult than SBS paper printing.In particular, the exact reproduction of color on a regular kraft board requires more care than printing on a bleached kraft board.The effect of printing ink is very different from that of printing on bleached paper due to the dark brown nature of ordinary kraft paper.Because this had better use color bright-coloured printing ink, use more marked colour, such printing effect is better.Soft colors and pastes are most difficult to achieve the desired ink density, opacity and wear resistance.In addition, if necessary, you can add a bit of white in the ink first, will be conducive to achieve the desired soft tone or light color, which is very useful for copying soft colors and light colors.With the increasingly mature printing technology, some manufacturers even use UV ink, effectively improving the printing color effect.Almost all ink makers have developed inks for unbleached cardboard, and many have developed inks for printing on kraft paper.Therefore, before determining the best plan for the work should consult the ink manufacturers, according to the printing needs of the plant to choose different formula ink, reference ink manufacturers to provide color and ink on different paper printing effect, and finally determine the best ink.
2. Ink selection and paper coating.Because kraft paper is different from SBS board and general printing paper, it is uncoated, than bleached paper loose, the surface has a lot of porosity, permeability, and so on, which in the application of ink and coating should be considered comprehensively.For example, according to the analysis of the characteristics of kraft paper, generally choose flexographic printing better, and should not use offset press for full plate field kraft printing.As a result of kraft paper surface rough, soft texture, strong ink absorption, printing color matt, and printing ink will be pulled down the paper surface fiber (also known as pulled paper wool) phenomenon.
In the choice of ink, in view of the general kraft paper surface rough, porous, strong ink absorption characteristics, kraft printing needs more ink.Although high solidity and water-based coating is more effective than real solvent varnish, a cheap varnish on top can make the ink more colorful, so some cheap polish can be considered to improve ink adhesion, usually high spot water-based coating is more effective than full-solvent varnish.A precoated layer of viscous high solids or acrylic resin film can also prevent the separation of ink pigments from the resin and prevent uncrosslinked paint residues from sticking to the surface of the board.Can choose cover glossy oil to make a bottom twice, fill up, after covering paper surface, again print, namely wet press wet printing, the printing quality that such printing comes out has good gloss, ink layer thickness is even.In addition, surface coating can reduce external friction on the ink, especially on the whole cover ink protection.As a result, the supercoat will increase the wear resistance of the ink, especially in the printing field.In flexible printing, the number of high anilox roller has a good effect on the inking and coating in kraft printing, which can make the printing ink transfer and coating better.In addition, in order to improve the ink surface contact on kraft paper, should use softer flexible plates and pads.