Coating offers a wide variety of methods by which textile and film webs can process for various end uses. The materials to be processed, the coating, the required properties of the finished product, and the cost-effectiveness of manufacture often dictate choosing the right method. A best system is ultimately the one that produces a product, manufactured in the most economical way. In this research work major coating techniques used in coating fabrics were briefly mentioned and their rheological requirements were outlined. Coating pastes need to have very specific rheological properties because of the methods in which they are applied. In this study, rheological measurements of paste using DOP and DOA plasticizers and PVC-E with three K-values (69, 70 and 75) were studied. The results indicated that the PVC K-value and plasticizer type could influence the rheological behaviour. Under studied condition the coating pastes behaved as a non-Newtonian pseudoplastic to Newtonian fluid. The information presented here can help the right selection of coating and laminating method.

PLASTISOLs are the liquid suspension compositions containing polyvinyl chloride resin (PVC), plasticizers and extenders, with various applications such as automobile coatings as seam sealers, which converts to the flexible material using heat. Rheological and mechanical properties of these compositions are related to the type of reinforcing materials. Reinforcing materials like nano silica has been used for improvement of different properties of these compositions. In this research, using Taguchi method and optimized model calculated from experimental design, effect of PVC type, particle size of calcium carbonate, type of plasticizer and silica particle size on mechanical and rheological properties like viscosity, strength, hardness and morphology were investigated. Particle size was evaluated using scanning electron microscopy and the results were analyzed. Based on variance analysis, it was found that for reaching to the optimum process conditions and highest strength of PLASTISOL coatings, K-value for PVC resin must be about 70, mesh size of calcium carbonate about 1000, type of plasticizer was dibutyl phthalate (DBP) and nano silica particle size was about 200 nm.

The aim of this study was to improve the adhesion performance of plasticized polyvinyl chloride (PVC) coatings on steel substrates by using nanoparticles. For this purpose, the PVC PLASTISOL with different concentration of nano-silica was prepared and applied to bond steel joints. The adhesive strength of the joints was determined by single-lap shear test. Moreover, mechanical properties and microstructure of coating were investigated. The addition of 1wt % nano-silica to PLASTISOL dramatically increased the lap shear strength up to 4-fold, which was an outcome of the compatibilizing effect of silica. Young's modulus and tensile strength of plasticized PVC were slightly increased by adding nanoparticles, as well. The scanning electron microscopy (SEM) and atomic force microscopy (AFM) exhibited higher inclusion size in the coating having higher silica volume which was attributed to the agglomeration of nanoparticles. In the following, the effect of plasticizer composition on the adhesion strength by replacing some parts of dioctyl phthalate (DOP) plasticizer with more polar oil, epoxidized soybean oil (ESO) was examined. Although adding ESO improved the lap shear strength of the neat coating, its effect on the properties of the coatings containing silica was negligible.

The rheological behaviour of PLASTISOLs used in coated fabrics was studied by using a computer controlled concentric cylinder viscometer over the temperature range of 20-70°C. The results indicated that these pastes behave as Newtonian to pseudo-plastic fluids over the temperature range studied and the flow behaviour can be adequately described by the power-law model. The changes in the flow behaviour index (n) with temperature were statistically negligible (P<0.05). Both consistency index (k) and apparent viscosity (h) decreased with increase in temperature. The effect of temperature on the viscosity of the paste was modelled using the Arrhenius model. The activation energy for the temperature range of 20-42°C, varied between 3.90 and 4.64 kJ.mol-1. Increase in the temperature of the paste had influence on Newtonian behaviour of the paste.

The study of the rheology of polyvinyl chloride PLASTISOL is important because, at first, it is in a paste state and is usually applied by spraying. Moreover, controlling the gel and melting processes is possible by using rheology. This research investigated the rheological behavior of PLASTISOLs, including shear thinning behavior, thixotropy and gelation behavior. Also, long-term ageing was studied and it was found that PLASTISOLs turn into gel at a constant temperature for a long time period according to the concept of time-temperature superposition. Finally, the relationship between the samples' thixotropy and yield stress was evaluated to study the physical gel structure. The results confirm that thixotropy and yield stress in PVC PLASTISOLs are the same due to the fundamental physics and this is related to the strength of the microstructure.

PVC in the form of emulsion resin is used in PLASTISOL technology. Among its disadvantages: resin degradation during melt processing, high melt and gel temperature, resin's high viscosity in gel and melt temperature and low solubility can be mentioned. Copolymerization of vinyl chloride wih other monomers is a suitable route to modify such properties. Vinyl acetate comonomer improves many of the PVC problems. In this study copolymerization of vinyl chloride with 15.2 percent vinyl acetate was performed in a batch emulsion copolymerization system. Vinyl chloride content in both gas and liquid phase in the reactor, pressure variation and the effect of initiation on the reaction kinetics were investigated. Chemical structure and copolymer composition were characterized by FTIR and NMR spectroscopy. K-Value of the copolymers which is related to molecular weight was determined by solution viscometry.