Copying papers

Pressure-sensitive copying paper containing 431 was recently patented (1650). 2-Thiazolyldiazonium chloride enters in the composition of synthetic fibers with ion-exchange properties (1551). 

MiscelUneous. Mahc acid is used in pharmaceuticals (qv), cosmetics (qv), dentifrices (qv), metal cleaning, electroless plating (46), wash-and-wear textile finishing (47—49), for stabilization of heat-sensitive copying paper (50), as an inhibitor of gelation, livering, and agglomeration in cellulose nitrate Hqueurs, and in many other appHcations. 

Table 1 Hsts representative examples of capsule shell materials used to produce commercial microcapsules along with preferred appHcations. The gelatin—gum arabic complex coacervate treated with glutaraldehyde is specified as nonedible for the intended appHcation, ie, carbonless copy paper, but it has been approved for limited consumption as a shell material for the encapsulation of selected food flavors. Shell material costs vary greatly. The cheapest acceptable shell materials capable of providing desired performance are favored, however, defining the optimal shell material for a given appHcation is not an easy task.

Fig. 10. Cross section of a three-part business form prepared from carbonless copy paper where are microcapsules and ...

Microcapsules are used in several film coatings other than carbonless paper. Encapsulated Hquid crystal formulations coated on polyester film are used to produce a variety of display products including thermometers. Polyester film coated with capsules loaded with leuco dyes analogous to those used in carbonless copy paper is used as a means of measuring line and force pressures (79). Encapsulated deodorants that release their core contents as a function of moisture developed because of sweating represent another commercial appHcation. Microcapsules are incorporated in several cosmetic creams, powders, and cleansing products (80). 

Nickel salts and soaps have been used in electrosensitive copy paper for image development. Nickel bis-(3,5 di-Z fZ-butylsaHcylate) [68569-24-4] has been studied in pressure-sensitive color developer sheets (201). It has also been used for color stabili2ation of color copy paper (see Electroplating). 

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. 

Another important apphcation for 4-/ f2 -octylphenol is ia the production of phenoHc resias. Novolak resias based oa 4-/ f2 -octylpheaol are widely used ia the tire iadustry as tackifiers. The tackiaess of these resias biads the many parts of an automobile tire prior to final vulcanization. A specialty use for novolak resias based oa 4-/ f2 -octylpheaol is the productioa of a ziacated resia, which is formulated as a dispersioa ia water and coated onto paper ia combination with eacapsulated leuco dyes to yield carbonless copy paper (see Microencapsulation). Pressure from writing bursts the encapsulated leuco dye, which is converted from its colorless form to its colored form by the ncated resin (53). Novolak resias based oa 4-/ f2 -octylpheaol are also used ia the productioa of specialty printing inks. 

In more recent times, naphthalene has been used in condensation products from naphthalene sulfonic acids, utili2ing formaldehyde as additives to improve the flow properties of concrete these are referred to as superplastici2ers. Another newer appHcation is the production of diisopropylnaphthalenes. The mutual depression of the melting points in the mixture gives a Hquid which is used as a solvent for dyes in the production of carbonless copy paper. 

Ai- 4-(bis[4-(phenylamino)phenyl]methylene)-2,5-cyclohexadien-l-ykdene -3-methyl-ben2eneaminesulfate [57877-94-8] (20) have been claimed as positive CCAs (65). The absorption spectra of the triaryknethane dyes can be extended into the near-infrared region. The use of triaryknethane dyes as infrared absorbers for optical information recording media (66) and as infrared color formers in carbonless copy paper has been claimed. 

Biphenyl, terphenyl, and their alkyl or hydrogenated derivatives generally serve markets where price and performance, rather than composition, is the customer s primary concern. Performance standards for heat-transfer appHcations are usually set by the fluid suppHer. The biphenyl—diphenyl oxide eutectic (26.5% biphenyl, 73.5% DPO) represents a special case. This composition has become a widely recogni2ed standard vapor-phase heat-transfer medium. It is sold throughout the world under various trademarks. In the United States, Dow (Dowtherm A) and Monsanto (Therminol VP-1) are the primary suppHers. Alkylated biphenyls and partially hydrogenated terphenyls serving the dielectric and carbonless copy paper dye solvent markets likewise are sold primarily on the basis of price and performance characteristics jointly agreed on by producer and user. 

Short-chain alkylated biphenyls are the principal biphenyl derivatives in commercial use. They are generally produced by Hquid-phase Friedel-Crafts alkylation of biphenyl with ethylene, propylene, or mixed butenes. A series of mixed ethylated biphenyl heat-transfer fluids (trademarked Therm S-600, 700, 800) is marketed by Nippon Steel. A mixed diethylbenzene—ethylbiphenyl heat-transfer fluid is also available from Dow (63). Monoisopropylbiphenyl [25640-78-2] largely as a mixture of meta- and para-isomers is produced by Koch Chemical Co. Monoisopropylbiphenyl (MIPB) was selected by Westinghouse (64,65) as a PCB replacement in capacitors and this is its primary appHcation today. For a time MIPB was also employed as a PCB replacement in pressure sensitive copy paper, but this outlet has since given way to other dye solvents. A similar product consisting of a mixture of j -butylbiphenyl isomers [38784-93-9] (66) is currently the favored dye solvent for pressure sensitive copy paper (67) manufactured in the United States. 

Chlorinated paraffins are versatile materials and are used in widely differing appHcations. As cost-effective plasticizers, they are employed in plastics particularly PVC, mbbers, surface coatings, adhesives, and sealants. Where required they impart the additional features of fire retardance, and chemical and water resistance. In conjunction with antimony trioxide, they constitute one of the most cost-effective fire-retardant systems for polymeric materials, textiles, surface coatings, and paper products. Chlorinated paraffins are also employed as components in fat Hquors used in the leather industry, as extreme pressure additives in metal-working lubricants, and as solvents in carbonless copying paper. 

As plasticizers in paints, and as ink solvents in carbonless copy paper... 

The leucos 7a-d are described as useful in printing ink for preventing forgery,1 whereas 7e-g are used in pressure sensitive copying paper.2... 

Benzoyl leuco Basic Blue 3 (2) is a typical cyan leuco oxazine used in carbonless copy paper. To satisfy the requirements of new applications such as electrolytic recording and Color Dry Silver, new oxazine leucos have been... 

The driving force for this development followed the introduction of carbonless copying paper into the marketplace by the National Cash Register Company (NCR) in 1954. The principles of this system have long been described,3,4 and it suffices to demonstrate the color-forming reaction of CVL in Scheme 1. 

Since the introduction of carbonless copying papers, CVL has undoubtedly found the most widespread use as a phthalide color former. Hence, it is appropriate to describe in detail the various approaches to its synthesis, particularly as they are representative of the preparations of various other phthalides described herein. 

Triphenylmethane leuco dyes are far more important than the diphenylmethanes in terms of practical value. Use of triphenylmethane dyes for traditional applications of dyes is limited to dyeing wool, silk, leather, and polyacrylonitrile fibers. The largest portion of the annual production of this class of leuco dyes is consumed in the manufacturing of various copying papers. 

In 1954, the National Cash Register Company first marketed carbonless copying paper—NCR paper1—using Crystal Violet lactone (7)1 and benzoyl leuco Methylene Blue (8)2 as leuco dyes to make blue images. 

Fluoran compounds have an optically active spiro-carbon atom. Consequently, some fluoran compounds, especially those having an alkylamino group of four or more carbon atoms at 3 -position, have been found to exhibit crystal modifications as determined by X-ray diffraction. Each crystal modification reveals different physical properties such as melting point, solubility, and affinity with acidic compounds, resulting in different characteristics regarding use for carbonless copying papers, thermosensitive recording papers, and the like. 

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