Jing Lei Tai

Research and Manufacture of Nano-Silver Conductive Ink

Printing electronics technology promotes the application of conductive ink. In this paper, the manufacture of nano-sliver conductive ink is investigated. First, Spherical silver nano-particles were reduced from silver nitrate solution by liquid chemical reduction method, with hydrazine hydrate as reductant and PVP as surface-protection reagent. SEM was used to characterize the morphology of silver powders, and the mean particles size is 62.79 nm. Then, conductive ink was prepared with nano-silver particles made in this research as conductive fillers, polyurethane resin and acrylic resin as binders, and stearic acid as dispersant. In the last, the conductive ink was printed on the PCB substrate by screening printing. After the ink is dried, conductivity, abrasion resistance, and adhesion were tested. The experiment results shows that the order of sheet resistivity magnitude is 10-4Ω•m, the number of rubbing fastness is more than 6000, and the adhesion can be resisted repeatedly to tape tear.

Structural Effect of Thiol-Compounds on the Thiol-Ene Based UV Curable Adhesive

Three thiol-compounds with different functionalities were synthesized through esterification reaction which was prepared by 1, 4-butanediol, trimethylolpropane, and pentaerythritol and 3-mercapto propionic acid respectively. Thiol-compounds and polyurethane-acrylate prepolymer were blended with addition of photo-initiator in certain proportions in order to form polyurethane curing film under UV irradiation. The structure and properties of the thiol-compounds and the polyurethane curing film were characterized by NMR, FT-IR, and TG. The results showed that the thiol-ene addition reaction between the urethane acrylates and the thiol-compounds was preceeded. With the increase of functionality of mercaptopropionic acid ester, the thermal stability improved, and the T-peel strength enhanced. When the moral ratio of urethane acrylates and trimethylolpropane-3-mercapto propionic acid ester was 1:1, the adhesive showed the best mechanical properties and thermal stability with curing time 40s, T-peel strength 88N/m and 50 % mass loss at 369°C, respectively.

Research on Synthesis and Performance of Solvent-Free Aluminum-Plastic Composite Polyurethane Adhesive

A low-viscosity and solvent-free polyurethane adhesive was prepared with mixed polyester, polyether and IPDI as main raw materials. The influences of different moral ratios of polyester and polyether on reaction time, viscosity and water resistance, adhesive strength were researched. The effects of catalysts to adhesive were well discussed. The experimental results showed that polyurethane adhesives composed by mixed polyester and polyether had low viscosity and had better waterproof quality. The adhesives showed the best comprehensive properties when the mole ratio of OHs of polyether to OHs of polyester was 0.3/0.7. Catalysts added to this adhesive could speed the curing reaction, but it reduced the peel strength of the adhesives.

Research on the Infiltrating and Diffusing Model of Ink Droplet in Inkjet Imaging System

The infiltration and diffusion of ink droplet in paper coating have significant influence on the image quality in the inkjet imaging. The flight physical phenomenon of the ink droplet was researched and analyzed according to the hydrodynamic equations of multiphase flow discrete phase in this paper, and the energy distribution of ink droplet before contacting with the paper coating was calculated. Base on studying on the surface structure of paper coating, the mechanism of impact, infiltration and diffusion between ink droplet and paper coating also was researched in this paper from the perspective of energy conversion in the imaging process. The proposed mathematical model consisted of the factors of hydrodynamic characteristics for ink droplet and the physical characteristics of paper coating, we could get the maximum diameter of ink droplet spreading in paper coating through solving the model and obtain viscous loss and energy consumption in infiltration of ink droplet by experiment, and then calculated the average infiltration depth of ink droplet.

UV Curable Thiol-Ene Adhesive for Flexible Packaging Based on CO

An important thiol ester photosensitive monomer COMP (CO-based mercaptopropionate) was prepared via melt polycondensation method using castor oil (CO) and 3-Mercaptopropionic acid (3-MPA). Structure of the thiol-compounds was characterized by FT-IR, 1H-NMR. When the thiol compound was used as photosensitive monomer and polyurethane-acrylate prepolymer was used as main material in UV curable adhesive. The UV curable adhesive showed good curing behaviors and thermal stability with curing time 100s, T-peel strength 3.8N/25mm and shrinkage rate 8%; so the UV curable adhesive could meet the requirements for flexible packaging composite.

Data Dissemination and Visualization Browsing of Digital Map Based on Web

We proposed overall design of the visualization browsing map data in network environment in this paper. And we developed map data flow according to the data structure and attributes of map data base. We programmed one map display control, MapCtrl.ocx, with GUI in the specific implementation. It could browse the map by utilizing map data base and self-designed map symbol base. Furthermore, we detailed the specific process of programming the control and the related techniques, such as component technique, data exchange technique and display technique. We developed a prototype of map data visualization browsing system based on ActiveX in network environment, which could achieve several functions such as browsing vector graphics of map data on internet, operation and simple query and analysis.

Research on the Relationship between Ink Permeability and Dot Gain of Different Paper

In order to research the relationship between ink permeability and dot gain of different paper, four kinds of coated paper and two kinds of printing paper were chosen. Ink marks method was used to measure ink permeability of four kinds of coated paper and two kinds of common printing paper. After the ink marks were printed on each of the six kinds of paper, the length of them were measured, then the reciprocal of the ink marks length was multiplied by 1000 to obtain the value of the ink permeability. Inkjet printer was also used to print yellow GATF step-wedge simulating offset printing on the six kinds of paper, then using an optical densitometer to measure the dot gain. Conclusion shows that non-coated paper is higher in permeability than coated paper, which results in high percentage of dot gain.

Halftoning Method and Reproduction of Color Gamut in Digital Image Output

Image halftoning is the core technique of digital image output, which determines the quality of the color and tonal gradation reproduction. In this paper, the existing halftoning techniques were analyzed and evaluated, such as FM halftoning and AM halftoning, etc. And a new halftoning mode, frequency conversion amplitude modulation (FCAM), was proposed. This method is still based on AM halftoning, but it uses the different screen frequency for halftoning image of the different color version, so as to avoid moiré fringes on the smaller superposition angle. The use of new halftoning model can achieve halftoning image output which is more than 4 colors (such as 6 colors or 7 colors) without visual moirè pattern when overprinting. By the new technique, high-fidelity printing is achieved, and the color gamut of the output image is expanded, and we can get more vivid realistic effect of image transmission. We tested color gamut expansion of 6 colors and 7 colors high-fidelity printing, and obtained the expected conclusion by quantitative analysis.

Research into Digital Watermark Algorithm Based on Wavelet Domain

In this paper, the key research was focused on the algorithm based on wavelet domain after analyzing and comparing several watermark algorithms. Disperse Wave Transform(DWT) watermark and Disperse Cosine Transform(DCT) watermark are both belong to transform domain technology, and they have more robustness than spatial-temporal domain technology, and DWT is superior to DCT. DWT can use the spatial-frequency characteristics of Human Visual System, and Mosaic will not appear in reconstruct image. DWT also can use image fusion technology to disperse watermark into multiple scales of carrier data, and got more robustness. In this paper, watermark embedding based on wavelet domain in which raster data are carrier was performed, then extracting and detecting watermark were done. Experiment results show that digital watermark based on wavelet domain will get better invisibility and robustness, and can be used in following the data by digital fingerprint.

Study on Improvement of Photopolymerization Curing Performance of UV Ink

UV ink has many advantages such as less pollution, high curing speed, saving energy, so it has been widely applied in traditional printing and emerging digital printing. In this paper, the two curing principles in UV ink which are free-radical curing and cationic curing, are discussed and compared, and the factors that affect the curing rate are analyzed through the comparing experiment of the curing rate. In the last, the selection principle of photoinitiator is established by means of analyzing and comparing curing rate when various photoinitiator or photoinitiator combinations is used in UV-cured ink. These studies have certain significance for improving the curing efficiency of UV ink and its application.