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Thermoplastic Recording Compositions

IP.com Disclosure Number: IPCOM000096630D
Original Publication Date: 1963-Sep-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 3 page(s) / 15K

Publishing Venue

IBM

Related People

Anderson, HR: AUTHOR [+2]

Abstract

These three classes of plastic compositions are suitable thermoplastic recording media for use in a thermoplastic recording process. The first composition consists of poly (methyl methacrylate) of molecular weight 4980 and 40 parts of o-terphenyl per hundred parts of polymer. A range of compositions consisting of poly (methyl methacrylate) in a suitable molecular weight range and with or without a plasticizer, e.g., a terphenyl or tricresylphosphate, can be used.

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Thermoplastic Recording Compositions

These three classes of plastic compositions are suitable thermoplastic recording media for use in a thermoplastic recording process. The first composition consists of poly (methyl methacrylate) of molecular weight 4980 and 40 parts of o-terphenyl per hundred parts of polymer. A range of compositions consisting of poly (methyl methacrylate) in a suitable molecular weight range and with or without a plasticizer, e.g., a terphenyl or tricresylphosphate, can be used.

Another composition consists of poly (vinyltoluene) of molecular weight 3290, m-terphenyl in the concentration of 40 parts per hundred of polymer and butadiene/styrene (75/25) rubber in the concentration of 7 parts per hundred of polymer. Similar compositions consisting of poly (vinyltoluene) in a suitable molecular weight range with or without a plasticizer, e.g., a terphenyl, tricresylphosphate and/or a preferred rubber are equivalents. In addition, a composition comprising alphamethyl styrene and o-terphenyl (40 parts per hundred of the polymer) is usable.

Finally, there is a class of compositions consisting of copolymers of styrene and isoprene and o-terphenyl or tricresylphosphate either of which are in the concentration 40 parts per hundred of polymer. The specific copolymers of styrene/isoprene are: (1) 98/2, mw 2710; (2) 95/5, mw 2590; and (3) 90/10, mw 2490. Similarly, compositions consisting of copolymers of styrene and isoprene in a suitable molecular weight range with or without preferred low vapor pressure plasticizers can be used for thermoplastic recording.

The response and cycling characteristics of several thermoplastic compositions have been determined using both an in-air and an in vacuum technique of recording. The in-vacuum technique utilizes an electron beam to put a charge on a thermoplastic surface.

The thermoplastic composition is cast from a solvent (benzene) system onto a Pyrex glass plate with a thin conductive tin oxide coating (125 ohms per square) to produce a nominal thickness of 1 mil. A controlled pulse of current is used to obtain frozen-in deformations.

The in-air technique uses a corona discharge to apply the electrostatic charge. In this case, the thermoplastic compositions are cast from a solvent (benzene) onto 0. 5 mil type C MYLAR* to produce coating thicknesses in the desired range of 0. 2-1. 5 mils.

An etched grounded plate, either 200 lines/inch or equally spaced 10-milholes, is fixed against the MYLAR side during charging using various voltages, 200-1200 volts. While insulated from ground, the induced charge on the MYLAR side is neutralized with an equivalent exposure to the corona discharge. The charged film is placed in a Schlieren optical system to follow photoelectrically the development of deformation produced by a pulse of hot air.

One suitable composition consists of poly (methyl methacrylate) with a number-average molecular weight of 4980 and 40 parts of o-terphenyl per parts

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