Carbonless paper

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). 

Benzoyl leuco Methylene Blue (1), which is a phenothiazine leuco dye, has been known since 1900. The material was developed to extend the range of hues and colors obtainable in such applications as pressure-sensitive carbonless paper and to complement other classes of leuco dyes such as triarylmethanes, crystal violet lactone, and fluorans. Benzoyl leuco Basic Blue 3 (2), which is a phenoxazine leuco dye, is a more recent development. 

These two seemingly dissimilar applications have a common basis—both are examples of the pressure-sensitive release of a chemical. How are these products designed Tiny spherical capsules (microcapsules or microspheres) with a glass or polymer shell are filled with a liquid core and glued onto paper. For a scratch-and-sniff ad, the core of the microcapsules contains a liquid with the desired scent for carbonless paper, a liquid ink or dye is encapsulated within the... 

The five largest uses for PCBs prior to 1970 were dielectric fluids in capacitors, plasticizers, lubricants, transformer fluids, and hydraulic fluids. They were also used widely in protective coatings, sealers, putty, grinding fluids, printing inks, pattern waxes, carbonless paper, etc. (see Chap. 1). Because of this widespread PCB use they are found throughout the environment [363-365]. A number of important properties of PCBs are discussed below along with information on their distribution and persistence in the environment. 

Vapors and dusts from personal care products, cleaning products, fire retardants, insecticides, fertilizers, adhesives, carbonless paper products, industrial hazardous substance releases, etc. ... 

Success of all carbonless paper products depends on the microcapsules. leuco dyes, and reactive coaling. A number of leuco dyes are available. 

Pressure. Barochromic (pressure-sensitive) dyes change color with pressure. As with thermo chromic dyes, the effect may be due to a single dye or a composite system. Barochromic dyes find use in imaging (carbonless paper) and for testing pressure points in, for example, aeroplanes and cars. 

It was determined that the ideal stilt material should have a size 1.5-2.5 times the diameter of the microcapsules or microcapsule clusters. Since the microcapsules are often agglomerated into clusters of a maximum size of 10 pm, the optimal stilt diameter should vary from 15 to 25 pm, with an average of 20 pm.204 In addition, a round stilt material is more efficient than a polygonal material which can fracture the microcapsules by contact. It also should possess a certain rigidity to provide protection to the microcapsules during normal manipulation of the carbonless paper, but not be so... 

Phenol-formaldehyde resins find numerous applications in such areas as wood composites, fiber bonding, laminates, foundry resins, abrasives, friction and molding materials, coatings and adhesives, and flame retardants (JL). From a specialty chemicals standpoint, they are also used as developer resins in carbonless papers (2.). Conventional methods of preparation involve condensation of a phenol with formaldehyde under either acidic (novolak) or basic (resole) conditions (2). Their typical molecular weight range is from 800-4000 daltons (D) and includes a wide variety of alkyl or aryl substituted phenols (A)- The... 

Used in electrical capacitors, electrical transformers, vacuum pumps, and gas-transmission turbines. Formerly used as heat transfer fluid, hydraulic fluids, rubber plasticizer, and in carbonless paper, adhesives and wax extenders. Although the production and sale was discontinued in late 1977, it is still present in transformers and capacitors now in use. 

Environmental Uncomfortable humidity and temperature cigarette smoke photocopiers and video display terminals handling carbonless paper chilled, humidified air from mechanical ventilation level of lighting odor complaints organic debris/volatile organic compounds... 

Many credit-card slips do not have carbon paper. Nevertheless, when you sign the slip, an imprint of your signature is made on the bottom copy. The carbonless paper contains tiny capsules that are filled with the colorless compound whose structure is shown here ... 

FIGURE 5.81 Cross-section of a three-part business form made with carbonless paper. (After Thies, C. 1989. Biomaterials and Medical Applications, Encyclopedia Reprint Series, 1. 1. Kroschwitz, ed., pp. 346-367. John Wiley, New York.)... 

By far the single largest application of microcapsules is in carbonless copy paper used to make multipart business forms. The principle on which the carbonless paper is based is illustrated by the three-part business form depicted in Figure 5.81, which shows the bottom and/or top faces of the sheets coated with a layer of microcapsules and the acidic component, respectively. The capsules and the acidic material may also be coated on the same side and the product is then called self-contained carbonless copy paper. 

Complex coacervation can be used to produce microcapsules containing flavor, fragrant oils, liquid crystals, dyes, or inks as the core material. Capsules for carbonless paper applications were produced by complex coacervation process. 

Graphic arts carbonless paper, thermal Polyurea " Dye, pigments, toner, color... 

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

Functional material Electronic ink Carbonless paper Self-healing agent... 

In situ polymerization has been industrialized for several decades. The large-scale amino resin microcapsnles are widely applied for carbonless paper, fabric care, and PCM, etc. Even though free formaldehyde is a big concern for its development, as a conventional and economic process, and especially through which excellent thermally and mechanically stable microcapsules can be made, in situ polymerization continues as one of the leading industry methods of microencapsulation. 

In 1954, the National Cash Register Company (now NCR Corporation) and the Appleton Coated Paper Company (today s Appvion) collaborated to introduce the first carbonless paper. It was known then, as it is today, as the NCR PAPER brand of carbonless paper. The product was simply promoted as a new paper product that eliminates carbon paper. Some dubbed it the no carbon required paper. The first commercial sale took place on March 26,1954, and marked the first use of the NCR PAPER trademark. 

The NCR PAPER brand has been continuously manufactured by Appvion since 1954. The product revolutionized the forms industry by eliminating the mess and bother of carbon interleaves. Paper transactions became easier, faster, and cleaner for businesses, institutions, government, and service organizations of all kinds. Carbonless paper is used to make multipart business forms, invoices, and credit card receipts. 

During 1952 and 1953, Barry Green worked with the late Lowell Schleicher, another NCR Corporation scientist, to develop and refine the microencapsulation system. They coinvented the system that is used to produce much of today s carbonless paper and filed the patent for the system on June 30, 1953. 

The carbonless system consists of colorformers and oil-filled microcapsules dispersed within a solid coating. In a typical three-part business form, three kinds of carbonless paper work together as a system to transfer images cleanly and clearly from one sheet to the next (Figure 59.2). 

FIGURE 59.3 Cross-section of a carbonless paper with PAC capsules. 

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