US3055768A

US3055768A - Metallized product and method of forming the same

Info

Publication number: US3055768A
Authority: US
Inventors: Frederic H Lassiter
Original assignee: Individual
Current assignee: Individual
Priority date: 1957-11-29
Filing date: 1957-11-29
Publication date: 1962-09-25
Anticipated expiration: 1979-09-25

Description

Sept. 25, 1962 'F. H. LASSITER 3,055,768 METALLIZED PRODUCT AND METHOD OF FORMING THE SAME Filed Nov. 29, 1957 J IO INVENTOR. FREDERIQ H. LAssn-ER BY firmbm, QWH

. ATTORNEYS 3,55,768 Patented Sept. 25, 1962 free 3,055,768 METALLEZED PRODUCT AND METHOD OF FORMING Tim SAME Frederic H. Lassiter, 527 Lexington Ave, New York, NY. Filed Nov. 29, 1957, Ser. No. 699,669 6 Claims. (Cl. 117-46) This invention relates to a method of coating a base material to provide a smooth highly reflective non-porous surface thereon and the resulting product thereof. More particularly, the invention relates to metallizing at least one surface of a base material such as paper or paperboard to form foil paper for use as a wrapping material for cigarette packages or the like more economically than has been possible heretofore.

Foil paper which is presently available made by conventional processes is relatively expensive due to the fact that the malleable metal such as aluminum has to be taken through numerous processes to reduce the pig aluminum to thin foil. This considerably raises the cost of the aluminum for making foil paper. After the foil is formed, which foil is normally of one-half mil in thickness, the toil has to be fed in timed relation to the base material such as paper while both are secured together by a suitable adhesive or glue after which heat is applied to remove the moisture from the glue.

The present method hereinafter disclosed of forming foil paper permits pig aluminum, for example, which is relatively cheap, to be used in lieu of foil which is considerably more expensive, namely, more than three times the cost of the pig aluminum. This is accomplished by rendering the pig aluminum molten and spraying the molten aluminum in finely divided particle form onto the base material such as paper. Due to the molten state of the aluminum particles, the same adhere to the base material without the necessity or need of an adhesive or glue for bonding the same thereto. The deposited aluminum particles at this stage in the method present a substantially uniform rough optically dull gray porous coating to the base material. Subsequently, the coated material is passed through a pair or pairs of pressure or calender rolls or the like to highly compact the metal coating on the base and thereby greatly reduce its thickness and at the same time to smooth the coating to form a non-porous highly reflective substantially unform thin metallic coating theron having a high brilliance substantially the same as conventionally formed aluminum foil as well as having most of the other characteristics thereof.

It is old in the prior art to spray molten aluminum, for example, onto a suitable base material such as paper and thereafter pass the material through pressure rollers. However, in each instance the sprayed coating is not compacted sufficiently to provide a highly reflective brilliant surface. The prior art was not remotely concerned with forming a non-porous foil paper for a package wrapping but with forming a metal coating having a predetermined porosity for use in the electrical field to make electrodes or the like wherein a certain amount of porosity of the coating is desirable to increase the surface area thereof and in turn the electrical capacity.

With the foregoing background material in mind, it is the primary object of this invention to provide a more economical method of forming brilliant highly reflective foil paper products and the like than has been possible heretofore.

It is another object of the invention to provide a highly reflective non-porous foil paper simulating in all outward appearances conventional laminated foil paper such as commonly used, for example, in packaging cigarettes or the like.

Some of the objects of the invention having been stated, other objects will appear as the description proceeds,

2 when taken in connection with the accompanying drawings, in which- FIGURE 1 is a schematic view showing a web of material such as paper having a metal coating applied to its upper surface;

FIGURE 2 is a schematic elevational view showing a web mate-rial having a metal coating applied to both surfaces thereof;

FIGURE 3 is a highly magnified view of a web material with a metal coating applied to both surfaces thereof in accordance with the showing in FIGURE 2 but prior to the coating being calendered or smoothed;

FIGURE 4 is a highly magnified cross sectional view of the product shown in FIGURE 3 after the metal coating has been calendered and smoothed;

FIGURE 5 is a highly magnified cross-sectional view showing a coating applied to only one surface of a web material in accordance with the showing in FIGURE 1 and wherein the web material is somewhat thicker and has a rougher surface than the web material shown in FIGURE 3; and

FIGURE 6 is a highly magnified cross sectional View corresponding to the product shown in FIGURE 5 after the metal coating has been calendered and smoothed.

The term calendering herein used throughout the specification and claims encompasses the necessary compasting, smoothing, polishing, bufiing, etc. necessary to give the metallized product the desired characteristics as determined by the web base material and metal used and the end result desired. Accordingly, this term is not to be restricted to calender rolls such as shown in the drawings for illustrative purposes only but is to include any comparable or equivalent type of apparatus for performing the same or similar results.

The term highly reflective herein used throughout the specification and claims is used to characterize the high luster and brilliance of applicants silver-like prodnot and to differentiate the same from the dull gray products in the prior art formed from molten metal such as aluminum. Specular gloss readings on a group of applicants aluminum coated specimens using a Hunter multi-purpose reflectometer with a green filter and S-diaphragm setting at a angle were 75.3% to 79.7% (substantially the same as conventional aluminum foil paper on cigarette packages) based on a highly polished mirror as the standard for Products formed in accord ance with the prior art showed specular gloss readings of 16% to 41%. In no case did prior art specimens exhibit any brilliance remotely approaching the high readings of applicants product or the silvery appearance.

Referring now more specifically to the drawings and particularly FIGURE 1, reference numeral 10 designates a web base material which may be in the form of paper, paperboard, or the like. The web material 10 is shown wound on a suitable let-off roll 11 from which the web material is being withdrawn and in turn wound onto a suitable take-up roll 12 after being metallized in a manner to be explained in detail shortly. A hopper 13 for containing the metal to be deposited onto the web material 10 is shown positioned above the web material adjacent the let-off roll. The hopper l3 schematically represents any type of suitable conventional means for maintaining the metal to be deposited in molten condition while being fed by any suitable means to spray nozzles 14 communicatively connected therewith and out of the lower ends of which the molten metal is sprayed in finely divided particle form. The nozzles 14 are arranged with respect to each other and with respect to the width of the web material 10 to substantially uniformly coat the web material with an amorphous or irregular layer C of molten metal particles. Of course, if desired, the nozzles J may be arranged in such a manner as to give a particular effect such as stripes, for example, to the web material.

If desired or found necessary in certain instances, a water cooled roller 15 of the conventional type may be positioned immediately below the area of the web material 10 wherein the molten metal is deposited to prevent injury or damage to the web material. The roller 15 is constructed to have water circulating internally thereof to maintain the periphery of the roller which engages the web 10 in cooled condition at all times. It is apparent that the roller 15 serves to dissipate the heat from the molten metal applied to the web to thus prevent injury or damage thereto.

At this point, it is believed helpful to digress a minute as to why the web material 10 is not normally damaged by the molten metal particles even though a water cooled roller is not used to aid in dissipating the heat from the particles. The reason is quite simple. The molten metal particles are of such small size that their individual B.t.u. storage capacity even at elevated temperatures (approximately 1400 F. for aluminum when applied to the web material) is so limited as to permit contact with most web materials without damage. This permits showers of these particles to simultaneously be deposited to a moving combustible web material such as paper without damage.

The metal coated web material 10 as shown in FIG- URE 1 now passes through a calendering station wherein one or more pair of calender rolls 16 highly compresses and compacts the metal coating C, to substantially less than one-half its original thickness, while smoothing the same to transform the metal coating from the irregular roughened surface pictured in FIGURE 5 to a thin smooth highly reflective surface as shown in FIGURE 6. It should be noted that this calenderin g operation slightly compresses the base material while it is transforming the surface of the metal coating from an optically dull roughened appearance to a shiny smooth highly reflective surface. Although two pairs of calender rolls 16 are shown in FIGURE 1, only one pair of calender rolls may be used if so desired. However, it is preferred to employ two or more pairs of calender rolls since it has been determined that less stress and strains are placed upon the metallic coating if the transformation of the roughened surface to a smooth surface is carried out in a progressive manner.

To relieve the internal stresses in the metallic coating C after it has been calendered, the coated web material is preferably passed underneath a burner or flame treating unit 17 which heats the metal coating C to about 625 F. (when the metal coating is aluminum) to perform an annealing operation which strengthens the metal coating to overcome to a large degree the brittleness of the coating. The annealed coated web material 10 is then wound upon the take-up roll 12 which may be doffed at predetermined intervals if so desired to prevent the building up of an unduly large roll of metallized Web material.

Referring now to FIGURE 2 in the drawings, the schematic arrangement shown therein basically differs over the arrangement shown in FIGURE 1 by the provision of means so arranged as to apply a metal coating to both sides of the web material and means for annealing both sides of the web material after the same has been properly calendered. Accordingly, the same reference numerals will be employed for identical apparatuses as in FIGURE 1 and the same reference numerals with the prime notation added thereto for a duplicate of the same elements slightly re-arranged but having the same function as the corresponding elements in FIGURE 1.

Referring now more specifically to FIGURE 2, the web material 20 is shown being withdrawn from a let-off or supply roll 11 and directed below one or more spray nozzles 14 for spraying molten metal to the upper surfaces of the Web from a suitable molten metal reservoir or supply hopper 13. A water cooled roller 15 may be positioned immediately below the spray nozzle or nozzles 14 in a similar manner as in FIGURE 1 to cool the web material and prevent the molten metal from damaging the same. A pair of horizontally positioned but vertically arranged guide rollers 21, 22 direct the coated web material 26 upwardly to permit the opposite side of the web material to be sprayed by molten metal. As shown, the web material 20 upon disengaging the guide roller 22 is guided back over itself to take-up roller 12.

A molten metal supply chamber 13 suitably communicatively connected to one or more nozzles 14 is positioned above the web material 20 a short distance away from the guide roller 22 to spray molten metal onto the upper or opposite side of the web material from the surface thereof previously coated. As before, a conventional water cooled roller 15 may be employed for cooling the web material and dissipating the heat of the molten metal therefrom. In this particular arrangement, it will be noted that the water cooled roller engages the previously coated surface of the web material 20 rather than the web material itself, but since the previously applied metal coating is a good conductor of heat to rapidly dissipate the same, the web material sandwiched between metal coatings will not be damaged. If desired, the last metal coating applied to the web material 20 may be a different metal than that previously applied to the opposite side thereof to obtain certain decorative or utilitarian results.

Now the web material 20 coated on both sides thereof passes through pairs of calender rolls 16 in a similar manner as in FIGURE 1 to transform the dull porous rough metallic coatings C into smooth uniform highly reflective surfaces while highly compressing the coatings to substantially less than half their original thickness as exemplified by comparing the showing in FIGURE 4 with the previous state of the coating prior to calendering as shown in FIGURE 3. Now the coated calendered web material may be annealed in a similar manner as in FIGURE 1 by providing a burner 17 to heat treat the upper metallic coating on the web and a burner 17' to heat treat the lower coating after which the annealed material is wound upon the take-up roller 12.

As an example of the high degree of compression necessary for forming this new product a comparison will now be given of the before and after thicknesses of the product shown in FIGURES 5 and 6. In this embodiment, conventional adding machine paper having a thickness of approximately 3 mils was used as the base material and upon which was deposited a coating of molten aluminum having a thickness of approximately 4 mils. The overall thickness of the coated product was thus approximately 7 mils. After compacting and calendering, the overall thickness of the product was approximately 3 mils. Tests showed that the thickness of the metal coating was reduced approximately 75% to a thickness of approximately 1 mil and the paper to a thickness of approximately 2 mils. Other samples showed a reduction of the thickness of the metal coating as high as Further experiments disclosed as completely unsatisfactory those coatings that were reduced only about 50% in thickness. These coatings did not exhibit any appreciable degree of brilliance and to the eye exhibited a granular flake-like gray surface not remotely simulating silvery conventional foil commonly used on cigarette packages or the like.

Further tests disclosed that the transformation of the irregular dull aluminum metal coaings into a brilliant highly reflective silvery foil caused the coatings to undergo two distinct intermediate changes differing considerably in appearance. This was determined by increasingly varying the pressure of the calender rollers and in turn the compression of the metal coatings. The first distinct change in appearance was apparent with pressures sufficient to reduce the coating up to about half its original thickness. At this stage the coating was dull gray and exhibited only a small degree of brilliance. To the eye, the surface of the metal appeared granular and flake-like. With increasing amounts of pressure, the coatings exhibited a smoother surface but still retained to a large degree their flake-like appearance. However, the coatings in most instances now exhibited a darker gray color simulating gray enamel. It was only upon additional pressures being applied that there was a sudden break through of the silvery foil.

Any type of malleable metal such as aluminum, zinc, copper, etc. and/r alloys thereof may be used as the metallic coating material if so desired. The only known limiting factor is that the metal or alloy thereof employed must be readily reduced to molten stage so as to permit the same to be applied in finely divided molten particles. The temperature necessary for reducing the metal or alloy thereof to a suitable molten stage to be readily applied to a web base material will of course depend on the particular type of metal or alloy thereof used. Aluminum which is the preferred metal can readily be reduced and applied to a web material of paper, for example, by heating the same to 1200 to 1400 F. However, in some applications where an acetylene or propane type of torch is employed, it is not unusual to find the aluminum heated as high as 3500" F.

The annealing temperature necessary to relieve the stresses and strains in the metal coating and to permit the molecules thereof to re-align will of course also depend on the type of metal or alloy thereof employed. As an example, approximately 625 F. for aluminum is normally sufficient.

The speed of travel of approximately 150 feet per minute for the web material has been found to be a very satisfactory speed to obtain a uniform spray coating of metal thereon without any damage to the web material. Of course, the speed may be increased or decreased as desired to obtain a thinner or thicker coating of metal. Laboratory experiments have proven that when aluminum is used as the metal coating for a base material formed of paper, that the base material may be kept stationary for periods of time while molten aluminum is applied thereto without in the least bit injuring the paper base material. Therefore, it is apparent that in some applications of the invention the base material may be left in a static or stationary position while being coated if so desired without damaging the same. This phenomenon is explainable in the case of aluminum, which is a very good conductor of heat, by the fact that the particles of aluminum are of such small size that their individual B.t.u. storage capacity even at elevated temperatures is very limited and that they quickly give off the heat temporarily stored therein.

Although the invention has been described in relation to producing foil paper or foil paperboard for decorative or utilitarian purposes, it is within the scope of the invention to apply the metal coating to any suitable base material other than paper or paperboard such as woven or non-woven fabrics to be used as linings for garments,

ironing board covers, etc. wherein the highly reflective 60 characteristics of the coated material and/or a good vapor barrier is desired.

It is thus seen that there has been disclosed a novel method for metallizing a suitable base material which permits the metallized product to be formed in one con- 65 tinuous operation and at a considerable saving in cost over present conventional methods of forming similar products by laminating and the use of adhesive materials for bonding products together.

In the drawings and specification there has been set 70 2,598,344

forth a preferred embodiment of the invention and although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention being defined in the claims.

I claim:

1. A method of forming a metallized product comprising the steps of depositing finely divided molten particles of a metal onto a pliable fibrous base material to form an adherent substantially non-reflective amorphous coating thereon and then compacting the coating to less than half its original thickness while smoothing the same to form a highly reflective substantially uniform metallic coating directly adhered to the base material.

2. A product made in accordance with claim 1.

3. A method of providing a pliable fibrous web material with a smooth optically reflective thin metal coating directly bonded thereto comprising the steps of depositing finely divided molten particles of a malleable metal directly onto the pliable web material to form an adherent substantially uniform rough and optically dull coating thereon and thereafter passing the coated Web material through calender rolls to compact the coating to less than half its original thickness to form a very dense coating having a highly reflective surface.

4. A method of providing a pliable fibrous web material with a thin foil coating directly adhered thereto comprising the steps of moving the web material at substantially a uniform speed while depositing finely divided molten metal particles on opposite surfaces thereof to form a non-reflective amorphous coating directly bonded to both sides of the web material due to the molten condition of the metal, cooling the web material while depositing the molten metal, compacting the metal coatings to less than half their original thickness to form smooth brilliant and highly reflective surfaces thereon, and heat treating the metal coatings to anneal the same.

5. A method of providing a pliable fibrous web material with a thin foil coating directly adhered thereto comprising the steps of moving the web material at substantially a uniform speed while depositing finely divided molten metal particles on at least one surface thereof to form an irregular substantially non-reflective coating directly bonded thereto due to the molten condition of the metal, cooling the web material while depositing the molten metal, permitting the deposited metal coating to cool to ambient temperatures, compacting the metal coating to less than half its orginal thickness to form a smooth brilliant and highly reflective surface thereon, and heat treating the metal coating to anneal the same.

6. A method of making a smooth highly brilliant foil comprising the steps of depositing finely divided molten metal particles on a suitable fibrous pliable base to form an elongate porous metal strip having a substantially uniform rough and optically dull appearance, and then calendering the metal strip to less than half its original thickness to form a non-porous highly reflective substantially uniform metallic foil.

References Cited in the file of this patent UNITED STATES PATENTS 2,187,348 Hodson Jan. 16, 1940 2,400,304 Hammel May 14, 1946 2,404,824 Booe July 30, 1946 2,414,923 Batcheller Jan. 28, 1947 2,479,094 Bicknell Aug. 16, 1949 2,582,744 Brennan Jan. 15, 1952 Brennan May 27, 1952

Claims

1. A METHOD OF FORMING A METALLIZED PRODUCT COMPRISING THE STEPS OF DEPOSITING FINELY DIVIDED MOLTEN PARTICLES OF A METAL ONTO A PHILABLE FIBROUS BASE MATERIAL TO FORM AN ADHERENT SUBSTANTIALLY NON-REFLECTIVE AMORPHOUS COATING THEREON AND THEN COMPACTING THE COATING TO LESS THAN HALF ITS ORIGINAL THICKNESS WHILE SMOOTHING THE SAME TO FORM A HIGHLY REFLECTIVE SUBSTANTIALLY UNIFORM METALLIC COATING DIECTLY ADHERED TO THE BASE MATERIAL.