Vapor deposition device

3,198,167

Aug. 3, 1965

R. BAKISH ETAL

VAPOR DEPOSITION DEVICE

Filed March 10, 1961

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ATTORNEYS

3,198,167

Patented Aug. 3, 1985

United States Patent Office

3,198,167

VAPOR DEPOSITION DEVICE

Robert Bakish, Brighton, Donald B. Irish, Newtonville, and Iwan Marinow, AUston, Mass., assignors to Tise Ailoyd Corporation, Cambridge, Mass., a corporation of Massachusetts

Filed Mar. 10, 1961, Ser. No. 94,790 3 Claims. (Cl. 118—48)

The present invention relates to the deposition of metal on sheet material and, more particularly, to the deposition of metal onto paper from a gaseous compound of which the metal is a component. In the coating of paper, many of a variety of requirements must be met. Thus, in the production of metal coated decorative paper, deposition must be effected rapidly and inexpensively. And in the production of metal coated capacitor paper, deposition must be precisely controlled to meet specific characteristics. In all cases, temperature, pressure and time must be selected carefuly in order to avoil scorching and outgasing of the paper and to ensure adherence and uniformity of the metal coat.

The primary object of the present invention is to provide a novel device by which a metal may be deposited onto an elongated sheet from a gaseous metal bearing compound under precisely controlled conditions of temperature, pressure and time. The device is characterized by a drum around which the elongated sheet is tensioned and which defines, in conjunction with an associated jacket, an annular chamber for subjecting the elongated sheet to the metal bearing vapor in a novel manner. The process involves, the steps of heating the elongated sheet, which specifically is composed of paper, and depositing on one of its faces a metal from its vapor in a predetermined sequence that results in an adherent coat of high quality.

Other objects of the present invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the apparatus involving the several components and the relation and order of one or more such components with respect to each of the others, which are exemplified in the following disclosure, and the scope of which will be indicated in the appended claims.

For a fuller understanding of the nature and objects of the present invention, reference should be had to the following detailed description, taken in connection with the accompanying drawings, wherein:

FIG. 1 is a cross-sectional diagrammatic view, partly broken away, of a device for performing a process in accordance with the present invention; and

FIG. 2 is a perspective view of a component of the device of FIG. 1.

The specific process performed by the device of FIGS. 1 and 2 involves the steps of advancing an elongated sheet of paper from one of a pair of adjacent rollers through an annular path to the other of the pair of adjacent rollers, the path being defined by the outer surface of a drum and the inner surface of a casing. The annular path in profile may be thought of as extending throughout almost the whole extent of a closed curve. The sheet is tensioned against the outer surface of the drum to prevent the back of the paper from being affected by the deposition process. A part of the outer surface of the drum is heated so that heat is transmitted from the rear face of the sheet to its front face at which metal deposition is to occur. The inner face of the casing is provided with an opening, adjacent to which is a rotary cage containing the metal bearing compound from which the metal bearing vapor is to be formed. The metal bearing vapor is formed by flowing an auxiliary gas through this cage and the resulting mixture of metal bearing vapor and auxiliary gas is directed through the opening into the annular path. In this system, the metal bearing compound is an organometallic, a metal hydride, a metal carbonyl or a metal halide, which may be heated, in the presence of a suitable auxiliary gas, to an elevated temperature at which decom5 position of the vapor and deposition of the metal occurs.

It is known that useful rates of metal deposition from such gaseous metal bearing compounds occur generally within the range of from 200° to 1000° F. It has been found that paper can withstand, without appreciable 10 physical-chemical change, temperatures within the range of 200° to 1000° F. for periods within the range from 1 to 100 seconds, a typical paper being able to withstand without appreciable chemical change a temperature of approximately 500° F. for approximately 30 seconds. In 15 the illustrated process, successive increments of a paper sheet are momentarily heated and subjected to a metal bearing gas to cause metal to be reduced thereupon from a metal bearing gas. The auxiliary gas may be an active material such as hydrogen or an inert material such as 20 argon (or other noble gas) or nitrogen. Although the heated gas mixture is applied in a limited zone, it is free to diffuse rapidly into other zones of the annular path. The overall pressure in this zone preferably ranges from .1 to 15 p.s.i. in order to prevent outgassing of the paper. 25 Particularly good papers for the purposes of the present invention are calendered papers having at least a glossy surface at which the sheet is denser than it is in its interior. Such a paper is sold by S. D. Warren under the trademark Lusterwrap.

The gaseous metal bearing compounds preferably are selected from: carbonyls such as ferric carbonyl, molybdenum carbonyl, nickel carbonyl, chromium carbonyl, tungsten carbonyl and cobalt carbonyl; alkyls such as aluminum diisobutyl, aluminum triisobutyl, aluminum triethyl and molybdenum ditoluene; aryls such as chromium dibenzene, molybdenum dibenzene, vanadium dibenzene and vanadium dimesitylene di-iodide; olefins such as biscyclopentadienyls of iron, manganese, cobalt, nickel, rhodium and vanadium; esters such as cupric acetylacetonate, manganic acetylacetonate, titanyl acetylacetonate, platinum acetylacetonate, nickel acetylacetonate, dibutyl tin diformate, copper formate and copper acetate; nitro compounds such as copper nitrosyl and cobalt nitrosyl carbonyl; hydrides such as antimony hydride, copper hydride, aluminum hydride, and tin hydride; and combinations and mixtures thereof such as alkyl and aryl carbonyls including benzene chromium tricarbonyl, phenathrene chromium tricarbonyl, naphthalene chromium tricarbonyl, o-xylene chromium tricarbonyl, benzene molybdenum tricarbonyl, cyclo-octadiene molybdenum tricarbonyl; biscyclopentadienyl chlorides, bromides and diodides of titanium, zirconium, hafnium, vanadium, molybdenum, tungsten and tantalum, cyclopentadienyl carbonyls such as cyclopentadienyl manganese tricarbonyl, bis-cyclopentadienyl carbonyls of molybdenum, tungsten or iron, carbonyl halogens such as sodium carbonyl bromide, ruthenium carbonyl chloride, and organo hydride compounds such as aluminum diethyl hydride and aluminum dimeth60 yl hydride.

The device illustrated in FIGS. 1 and 2 for performing the process of the present invention is shown generally as comprising an outer jacket 20 and an inner drum 22 which define therebetween an annular chamber 24. Preferably the distance between the outer surface of drum 22 and the inner surface jacket 20 ranges between ¥32 and »4 of an inch and preferably is approximately Vs of an inch. A rear panel 26 and a front panel 28, both of which are connected to edges of jacket 20 and drum 22, complete the enclosure of chamber 24 as well as the hollow interior of drum 22. Jacket 20 is open at a restricted upper section 30, which is adjacent to a pair

167 to approximately 90° C., is-introduced through ports. 60, 62 and 64. In consequence of the passage of nitrogen through rotating cage 72, the vapor of molybdenum carbonyl, heated to approximately 90° C., is introduced into plating, zone 50. The partial pressure of the nitrogen is approximately five times the partial pressure of the molybdenum carbonyl. The total pressure throughout chamber 24 is approximately 50 mm./mg. Filaments 51 and 56 both generate a decomposition temperature of approximately 250⁰ C. The flow rate through the plating chamber is approximately .5 cubic foot per hour. When the paper is advanced at a rate of 2 inches per minute a molybdenum layer approximately .001 inch thick results., . . Example II .The foregoing process is repeated except that the.auxiliary gas is nitrogen and the metal bearing gas is chromium dicumene.

.Example III

The process of Example I is repeated except that the auxiliary gas is nitrogen and the metal bearing gas is iron dodecacarbonyl, the decomposition temperature being 135° C.

Example IV

Example I is repeated except that the inert gas is argon and the metal bearing gas is cyclo-octadiene molybdenum tricarbonyl, the decomposition temperature being approximately 110° C.

Example V

The process of Example I is repeated except that the auxiliary gas is hydrogen and the metal bearing gas is copper acetylacetonate, the decomposition temperature being approximately 300° C.

Example VI

The process of Example I is repeated except that the auxiliary gas is hydrogen and the metal bearing gas is aluminum hydride, the decomposition temperature being 100° C..

Since certain changes may be made in the above apparatus without departing from the scope of the invention herein involved, it is intended that all matter contained in the above description or shown in the accompanying drawing shall: be interpreted in an illustrative and not in a limiting sense.