Pressure-Sensitive Recording Materials

Pressure-sensitive recording materials are obtained by dissolving a triphenylmethane leuco dye in a solvent composed of paraffin oils. The microcapsules are formed from a water-soluble106 or water-dispersible material.107,108 Leuco dyes dissolved in sunflower oil are microencapsulated in a solution containing a melamine-HCHO precondensate and coated on the back side of a paper sheet. Contact of the microcapsule-coated sheet with an acid-coated receptor sheet allows the color formation to occur. 

A clay mineral and/or its acid-treated products109,110 are used as color developers. A diphenylmethane derivative of structure 82 has been micro- 

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Heteroarylmethane Dyes. Dyes of this class usually have either one or two lieteroaiyl groups attached to die methane carbon atom. Trihetarylmediane dyes are known and have been investigated for their pharmacological activity as well as their color characteristics. These types of triarylmethane dyes and their derivatives are used as color formers in thermoreactive and pressure-sensitive recording materials. 

Green BK. Pressure-Sensitive Record Materials. US Patent No. 2, 1955 712, 507. 

Fig. 5.11. The study of shock compressibility of pressure-sensitive magnetic alloys was carried out with the quartz gauge impact technique. Loading was either with the specimen material or a quartz gauge. Resulting stress pulses were recorded with a quartz gauge (after Graham et al. [67G01]).

Use Magnetic recording tape, drafting and engineering reproduction materials, metallic yarn, roll leaf, pressure-sensitive tapes, packaging, dielectric material in capacitors, wire and cable, motors, generators, transformers, and oils. 

Phthalide derivatives are of major importance in the dye industry, particularly in the area of recording material color formers. Pressure-sensitive carbonless copy paper and thermal recording paper are typical applications. Five principal structural classes have been developed extensively the xanthene dyes (fluorans (208)), 3,3-diarylphthalides (209), spirofluorenes (210), 3,3-bis(di-arylethylene)phthalides (211), and 3-substituted phthalides <84Mi 208-03>. Some of these structures are common to many familiar acid/base indicators, dyes, biological stains, or laser dyes such as fluorescein (212) and phenolphthalein (213) ,... 

Miyamoto, A. Pressure-sensitive microcapsular recording material. GB 2101648,1983. 

The measurement of the linear elastic properties is normally done through osciUatory measurements where strain, frequency, and temperature are controlled. If the material behaves perfectly elastically, then the stress recorded is in phase with the applied strain. If the material has no elasticity, but instead behaves perfectly viscously, then the recorded stress will be proportional to the strain rate, which is 90° out of phase with the applied strain, peaking where the strain is 0 in each sinusoidal cycle. Pressure-sensitive adhesives are viscoelastic materials and thus the recorded stress will peak in each cycle somewhere between 0° (in phase) and 90° (out of phase) with the applied strain. The tangent (sin/cos) of this phase angle 0 is a measure of the relative viscous to elastic contributions to the adhesive s stress response. When a material approaches its Tg tan delta (tan 6) increases. The temperature at... 

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