Light cured resin
Water-based UV ink generally by the base resin, photoinitiator, additives and water.Base resin is the main component of the ink system, ink curing film performance is mainly determined by the base resin.Commonly used resins are: unsaturated polyester, polyurethane acrylates, esterified acrylic acid, polyester acrylates.
The unsaturated polyester used for light curing waterborne ink is prepared by esterification reaction of diol or polyol and maleic anhydride.In order to make the resin hydrophilic, diol (such as polyethylene glycol) can be used to introduce hydrophilic structure, and the photoactivity can be obtained by sealing the end with acid or alcohol containing photoactive groups.
Polyurethane acrylates are the most studied systems.Gravure water plastic compound ink and the general polyurethane acrylate difference is only how to introduce hydrophilic structure in the molecule.Water-based printing inks are similar to the unsaturated polyester mentioned above.For example, polyethylene glycol can be used to introduce non-ionic hydrophilic chain segments;The carboxyl group was introduced into dimethylolpropionic acid (D M P A) to obtain ionic self-emulsifying resin.
Gravure water - based plastic table printing ink
The photoactive groups can be introduced by the reaction of hydroxyl of hydroxyl ethyl (H E A or H E M A) acrylate with polyurethane terminal isocyanate (-nco), or the esterification reaction of acrylic acid with hydroxyl terminal polyurethane.Acrylic esterified polyacrylic acid has the advantages of low price, easy preparation, rich ink film and good luster.In general, hydrophilic carboxyl groups can be introduced by copolymerization of acrylic acid and various acrylates, and hydroxyl groups or epoxy groups can be introduced by copolymerization of hydroxyethyl (methyl) acrylate or glycidyl (methyl) acrylate to further introduce oxyacrylate, so as to obtain photoactivity.
Gravure water - based plastic compound ink
In addition to the initiator to the light of the oily system used at the request of the absorption properties and yellowing of the same, light initiator for water-based system will also have to be compatible with aqueous environment, low volatile requirements, to ensure that the ink film predrying (generally in the 60 ~ 80 ℃) can still maintain the required concentration.Darocur 2959 is the most widely used photoinitiator, because its molecule is one more hydroxyethoxy group than Darocur1173, so its solubility in water is relatively large (the solubility of the parent Darocur1173 is only 0.1%), so it is easy to evaporate in pre-drying.