Preparation of UV-cured pigment/latex dispersion for textile inkjet printing

Study on the quality and inkjet printing effect of the prepared washing-free disperse dye ink

With the rapid development of digital inkjet printing, it will inevitably lead to the uneven quality of inkjet printing ink products on the market. Therefore, making a more comprehensive and accurate quality evaluation of digital printing ink is particularly important. In this study, a short process and environment-friendly washing-free disperse dye ink was prepared based on the research on ink quality. The quality of printing ink is closely related to its physical properties, printing ink stability, inkjet performance, and inkjet printing effect. The microdistribution state of water for washing-free disperse dye ink was analyzed by LF-NMR, and the influence of the microstate of water on the macro physical properties of the ink was clarified. The physical properties (particle size, pH value, surface tension, viscosity, rheological properties, etc.) of the washing-free disperse dye ink were systematically tested and analyzed. At the same time, the stability (weatherability, the temperature sensitivity of viscosity, and shear stability) and inkjet performance (drive waveform A, B, and C) of washing-free disperse dye ink were systematically investigated. Finally, the inkjet printing effect of washing-free disperse dye ink was evaluated. This study systematically examined the quality and printing effect of the prepared washing-free disperse dye ink and provided quality evaluation reference for the development of high-quality washing-free disperse dye ink.

Photopolymerization of Macroscale Black 3D Objects Using Near-Infrared Photochemistry

The efficiency of the photopolymerization technology significantly decreases when the color of materials blackens, which is contributed by the limitations of light penetration. Herein, we demonstrate rapid generation of black 3D objects up to the centimeter level in size based on melanin using near-infrared (NIR) photochemistry. Melanin, of a low absorption coefficient in the NIR range, allows thorough penetration of the 980 nm light to induce emission from upconversion nanoparticles (UCNPs) for initiating UCNP-assisted photopolymerization (UCAP). A model that describes light-attenuation gradients and dose-dependent kinetics in UCAP-guided NIR photochemistry is developed. Notably, the established model for the UCAP concept provides sufficient vertical light penetration to form scale-predictable black materials and instructs 3D printing applications. The critical control parameters were evaluated, and it was shown that complex macroscale black objects can be processed within dozens of minutes. The modeling methodologies integrated with rich functional fillers will further extend the versatility of UCAP technology in device design and manufacturing.

Silver Eco-Solvent Ink for Reactive Printing of Polychromatic SERS and SPR Substrates

A new reactive ink based on a silver citrate complex is proposed for a photochemical route to surface-enhanced Raman spectroscopy active substrates with controllable extinction spectra. The drop-cast test of the ink reveals homogeneous nucleation of silver and colloid particle growth originating directly from photochemical in situ reduction in droplets, while the following evaporation of the deposited ink produces small nano- and micron-size particles. The prepared nanostructures and substrates were accurately characterized by electron microscopy methods and optical extinction spectroscopy. Varying the duration of UV irradiation allows tuning the morphology of individual silver nanoparticles forming hierarchical ring structures with numerous "hot spots" for most efficient Raman enhancement. Raman measurements of probe molecules of rhodamine 6G and methylene blue reached the largest signal enhancement of 10⁶ by the resonance effects.

Fabrication of reactive pigment composite particles for blue-light curable inkjet printing of textiles

The Reactive Phthalocyanine Blue (RPB) was fabricated by two-step method, and then used to prepare blue light curable inks. After injection, RPB can participate in the copolymerization of oligomers and monomers under blue-LED irradiation.

Nonaqueous Dispersion Formed by an Emulsion Solvent Evaporation Method Using Block-Random Copolymer Surfactant Synthesized by RAFT Polymerization

As surfactants for preparation of nonaqueous microcapsule dispersions by the emulsion solvent evaporation method, three copolymers composed of stearyl methacrylate (SMA) and glycidyl methacrylate (GMA) with different monomer sequences (i.e., random, block, and block-random) were synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization. Despite having the same comonomer composition, the copolymers exhibited different functionality as surfactants for creating emulsions with respective dispersed and continuous phases consisting of methanol and isoparaffin solvent. The optimal monomer sequence for the surfactant was determined based on the droplet sizes and the stabilities of the emulsions created using these copolymers. The block-random copolymer led to an emulsion with better stability than obtained using the random copolymer and a smaller droplet size than achieved with the block copolymer. Modification of the epoxy group of the GMA unit by diethanolamine (DEA) further decreased the droplet size, leading to higher stability of the emulsion. The DEA-modified block-random copolymer gave rise to nonaqueous microcapsule dispersions after evaporation of methanol from the emulsions containing colored dyes in their dispersed phases. These dispersions exhibited high stability, and the particle sizes were small enough for application to the inkjet printing process.