Pressure sensitive recording paper

Until 1960s, proton exchanged or acid treated clays were used as cracking catalysts. They have also proved to be good catalysts for many industrially important reactions like alkylation [1], dimerization and polymerization of unsaturated hydrocarbons [2], Diels Alder condensation [3] etc. Moreover acid treated clays are commonly used commercially for decolourising oils [4] and also in colour formation with leuco dyes in pressure sensitive recording paper [5]. 

PRESSURE SENSITIVE RECORDING PAPER (CARBONLESS PAPER)... 

Solid acids are utilized as one component of pressure sensitive recording paper. The principle of the carbonless paper is indicator color change by adsorption on solid acids. The model construction of carbonless paper consists of a set of two types of paper as schematically shown in Fig. 6.4. The top sheet is coated with indicators encapsulated in microcapsules, and the bottom sheet is coated with solid acids. Applying pressure to the top sheet destroys the microcapsule, and the indicator is released and transferred to the solid acids on the bottom sheet to be adsorbed. 

Carbonless Copy Paper. In carbonless copy paper, also referred to as pressure-sensitive record sheet, an acid-sensitive dye precursor, such as crystal violet lactone or /V-hen2oy11eucomethy1ene blue, is microencapsulated with a high boiling solvent or oil within a cross-linked gelatin (76,83,84) or in synthetic mononuclear microcapsules. Microcapsules that have a starch binder are coated onto the back of the top sheet. This is referred to as a coated-back (CB) sheet. The sheet intended to receive the image is treated on the front (coated-front (CF)) with an acid. When the top sheet is mechanically impacted, the dye capsules mpture and the dye solution is transferred to the receiving sheet where the acid developer activates the dye. 

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. 

Electrophoretic ink Carbonless paper, thermal-sensitive paper, pressure-sensitive recording Self-heaUng agent... 

Pressure-sensitive recording Methyl vinyl France 2,012,741 1970 Papers National Cash Register ... 

Two types of recorder are in common use potentiometric and galvanometric. Potentiometric recorders are more expensive and more versatile but galvanometric recorders are usually adequate for the experiments described in this manual. The writing system may use ink, capillary flow or pad, or temperature or pressure sensitive paper. Capillary flow pens are particularly unreliable. 

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) ,... 

Coatings for metallic films Paper coatings Hair spray resins Pressure- and Heat-sensitive recording resins Adhesives coatings Antistatic film coatings Thermosetting resins Diazo coatings for vesicular substrates... 

IR spectra were recorded on a Perkin-Elmer model 225 spectrophotometer, and NMR spectra were recorded on a Varian T 60 spectrometer. Rotations were determined using a Perkin-Elmer model 141 polarimeter with a sensitivity of 0.005°, neat in a 1 dm tube. Elemental analyses were performed by a Perkin-Elmer model 140 elemental analyzer. The high pressure equipment used was the same as described in previous papers (4,14),... 

It is the most commonly used barometer. Aneroid means without liquid. The most important part in the aneroid barometer is a small shallow metal can. Almost all the air is pumped out of it. Hence it is sensitive to air pressure. It is supported by a spring to prevent it from collapsing. Barograph is actually an aneroid barometer with a pen or a stylus instead of a pointer. It records the pressure on a rotating graph paper. 

---