Screen & Inkjet Inks Chemicals

Plastisol inks consist of PVC resin (dispersion or suspension grade) dispersed in a plasticizer (diisononyl phthalate or phthalate-free alternatives such as DINCH or citrate esters) along with pigments, fillers, and additives. The PVC/plasticizer ratio controls gel point, viscosity, and final film hardness. Plastisols are 100% solids and cure thermally at 150–165°C.

Piezoelectric inkjet inks must have precisely controlled viscosity (8–15 mPa·s at jetting temperature), surface tension (25–40 mN/m), and particle size (ideally < 200 nm for pigment inks to prevent nozzle blocking). pH must be stable over storage. Ink formulation must avoid solvents that attack printhead materials (piezo ceramics, diaphragm membranes).

UV screen printing inks use epoxy acrylate or urethane acrylate oligomers as primary binders, reactive monomers for viscosity adjustment, and photoinitiators for cure. They are 100% solids with no solvent and cure instantly under UV or LED UV. Key performance criteria are adhesion to the substrate (plastic, metal, glass), hardness, and flexibility. Adhesion promoters (organosilanes) improve adhesion on non-porous surfaces.

Textile plastisol inks must cure at 150–165°C for 60–90 sec without scorching the fabric. Soft-hand additives (silicone modifiers) reduce stiffness on the printed area. Dye-migration blockers (acrylic-based) prevent polyester-dye sublimation through the print. Heavy-metal-free formulations are mandated by EU REACH and US CPSIA for children's wear, and phthalate-free plasticizers are increasingly standard.

Industrial inkjet for coding (CIJ continuous and TIJ thermal) uses fast-drying solvent or alcohol-based formulations with specialty pigments or dyes. Adhesion promoters are critical for marking on metal, glass, and plastic substrates. UV-cure inkjet is gaining adoption for permanent industrial coding due to instant cure, chemical resistance, and the ability to mark non-porous surfaces without solvent emissions.

Direct-to-garment (DTG) textile inkjet uses water-based pigment inks with specific dispersants and binders compatible with cotton, polyester, and blends. Pre-treatment with cationic polymers improves color saturation and wash fastness. UV-cure DTG inks are emerging for synthetic fabrics. Wash fastness is verified per AATCC 61 (color change after 5 wash cycles), with target ≥4 on the gray scale for commercial garments.