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Left: individual linear polymer chains Right: Polymer chains which have been cross linked to give a rigid 3D thermoset polymer. In materials science, a thermosetting polymer, often called a thermoset, is a polymer that is obtained by irreversibly hardening ("curing") a soft solid or viscous liquid prepolymer (). [1]
Thermochromic ink (also called thermochromatic ink) is a type of dye that changes color in response to a change in temperature. [ 1 ] [ 2 ] [ 3 ] It was first used in the 1970s in novelty toys like mood rings, but has found some practical uses in things such as thermometers, product packaging, and pens. [ 4 ]
Thermal-transfer printing is done by melting wax within the print heads of a specialized printer. The thermal-transfer print process utilises three main components: a non-movable print head, a carbon ribbon (the ink) and a substrate to be printed, which would typically be paper, synthetics, card or textile materials.
Traditionally, the advantage of dye-sublimation printing has been the fact that it is a continuous-tone technology, where each dot can be any color. In contrast, inkjet printers can vary the location and size of ink droplets, a process called dithering, but each drop of ink is limited to the colors of the inks installed. Consequently, a dye ...
Most thermal printers are monochrome (black and white) although some two-color designs exist. Grayscale is usually rasterized because it can only be adjusted by temperature control. [3] Thermal-transfer printing is a different method, using plain paper with a heat-sensitive ribbon instead of heat-sensitive paper, but using similar print heads ...
Through conduction from the paper, the powder temperature rapidly increases and starts melting. When the process is correctly adjusted, the center of the largest filmed areas reach sufficient quality level as the product exits the heater. The melted ink then solidifies as the product cools. This process is sometimes produced using manual powdering.
Phenol-formaldehyde resins, as a group, are formed by a step-growth polymerization reaction that can be either acid- or base-catalysed.Since formaldehyde exists predominantly in solution as a dynamic equilibrium of methylene glycol oligomers, the concentration of the reactive form of formaldehyde depends on temperature and pH.
A PVA hydrographic film, which has been printed on with a desired graphic image using latex or pigment-based inks, is carefully placed on the water's surface in the dipping tank. Recommended water temperature for the dip tank is 90°F (32°C). The clear hydrographic film is water-soluble and should dwell on top of the water for 60-75 seconds.