Preparation of polyurethane acrylate‐based titanium dioxide pigment and its use in blue light‐curable ink

Abstract Polyurethane acrylate‐based titanium dioxide was used to prepare blue light‐curable inks as both a white pigment to replace the original white pigment and as an oligomer. The polyurethane acrylate‐based titanium dioxide was fabricated using a two‐step method. In the first step, the titanium dioxide was grafted with γ‐aminopropyltriethoxy silane, and the grafting process was studied. Second, amino‐modified titanium dioxide was used to prepare polyurethane acrylate‐based titanium dioxide, which was then used to configure the blue light‐curable polyurethane acrylate‐based titanium dioxide ink. Fourier Transform–infrared spectroscopy indicated that the amino‐modified titanium dioxide and polyurethane acrylate‐based titanium dioxide were prepared successfully. The content of the amino groups on the surface of the amino‐modified titanium dioxide could be effectively controlled by adjusting the pH value. Moreover, by increasing the content of the amino groups, the viscosity decreased and the photopolymerisation efficiency increased, which was attributed to the formation of branched structures and the promoting effect of the amino groups on the titanium dioxide. The inks with decreased viscosity and branched structures displayed excellent cross‐linking properties: viscoelastic transition was achieved within 10 seconds and the final moduli were in the range of 36‐55 kPa. The cross‐linking degree and rate were more than seven times those of unmodified ink. The ranges of elongation and stress were 95%‐165% and 1.9‐4.3 MPa, respectively, and the amino group content varied from 0% to 0.101%. In general, polyurethane acrylate‐based titanium dioxide was shown to be suitable for blue light‐curable ink.