US2245045A - Coated paper - Google Patents

Description

' June 1941- w. J. MONTGOMERY .ETAL 2,245,045

COATED "PAPER' Original Fil ed Jan. 25, 1929 2 Sheets-Sheet l gwvQ/YM;

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June 10, 194 w. J. MONTGOMERY I'ZTAL 2,245,045

COATED PAPER Original Filed Jan. 25, 1929 2 Sheets-Sheet 2 J, Patented June 10, 1941 UNITED (STATE COATED PAPER William J. Montgomery and Donald B. Bradn Hamilton, Paper and corporation of Ohio Ohio, ass

ignors to The Champion Fibre Company, Hamilton, Ohio, a

Original application January 25, 1929, Serial No.

Divided and this application July 17', 1935,Serlal No. 31,91

This invention relates to a process of-applying. coating in the form of a continuous layer or iayersor in the form of mechanographs to paper, including coated paper, card board and the like,

and to the resulting products.

a In an application Serial No. 158,837, filed January 3, 1927, now Patent No. 1,719,166, issued July 2, 1929, in the name of Donald B. Bradner, one of the present applicants, there is described a process of calendering mineral coated paper according to which the coated paper is pressed against asolid finishing surface while the coating is in a fluid condition and the coating is hardened while in contact with said surface and subsequently detached therefrom, whereby it acquires a cast surface corresponding to that of the finishing surface. In carrying out said process the coating composition and the finishin surface must be so selected orprepared that after the coating has hardened it may be easily and substantially completely detached from the finishing surface.-

The present invention makes use of the same principle of hardening a coating while in contact with a solid finishing surface.

Ollie essential difference between the. process patent is that according to the present invention coating isfirst deposited on a finishing surface and then transferred to the paper,- whereas according to the patent coating is deposited on paper and contacted with a finishing surface without transfer of coating either to or from the hardened causing the paper to adhere to it and thereafter cleanly separating the paper-with the coating from the finishing surface.

' of the present invention and the process of said duction ofsteam or water.

" rows, underthe Fig. 4 15a plan view, and

Fig. 5 is a section online 5-5 of Fig. 4, of a piece of paper whichhas been coatedin accordance with the-invention.

Referring to Fig, 1 of the drawings, 1 is a cylinder mounted to revolve on the axis 2. The cylinder is hollow and'is provided with means for heating or cooling it, e. g., the axis 2 may be in theform of a perforated pipe for the intro- The outer surface of the cylinder provides th finishing surface. 3 is the paper which passes, as indicated by arpress roll I, around the cylinder I, and under the take-off roll 5. The paper may come from any suitable source of supply (not shown), such as a storage roll or a paper making machine, it may be either coated or uncoated and either wet or dry as will be explained later. The press roll I may be supplemented by other press rolls for holding the paper in contact with the cylinder or by a travelling apron. The as-" sembly 6-1-8 represents means for depositing coating on the cylinder I. 6 is a spray nozzle or atomizer of known construction for delivering the coating composition on to the cylinder; "I is a pipe delivering the coating composition to the spray nozzle 6, and 8 is a pipe for supplying compressed air to the spray nozzle. Assemblies 6'-I'8' and 6"-'I"-8" may be employed when it. is desired to apply a plurality of layers of coatingto the cylinder.

In the operation of this apparatus according to a specific embodiment ofthe invention, paper on which a coating has been freshly deposited and which is still in a wen-plastic and adhesive condition is fed continuously over the press roll lywhich may be rubber covered, on to the cylin- "der I.) At the same time coating is deposited on the cylinder I by the spray nozzle 6. Depend ing-upon the width of the paper a suitable number of spray nozzles, properly spaced, may be used to produce a substantially uniform and con- The invention is illustrated by the following detailed description in connection with the accompanying drawings in which- Fig. 1 is a diagrammatic.representationof a vertical side elevation of an apparatus suitable for carrying out one procedure in accordance with the invention;

. Fig. 21s a similar view of apparatus showing the preliminary. conventional coating; of the paper followed by the application of a coating in the form of a design: Fig. 3 is a plan view of a portion of the stencil belt;

tinuous coating on the cylinder. The cylinder is heated with steam at substantially atmospheric pressure. As the paper passes on to the cylinder its wet coating is firmly pressed into contact with the coating on the cylinder by the I paper passes aroundthe cylinder it and the coatings are dried, the temperature of the cylinder and its speed being ad- 'justed to this end so that when the paper reaches the take-off roll 5 the coatings are firmly bonded together and to the paper and, provided suitable coating compositions and finishing surfaces are used, the coatings are readily detached from theas may be obtained by electroplating chromium upon copper upon cast-iron and a coating composition composed of 100 parts of china clay, about 260 parts of water, parts of casein dissolved with sodium carbonate and 2 parts of sodium'stearate, the parts being by weight. This coating composition may be used on the paper also, provided the quantity of water is reduced,

, so that it will not flow back under the press roll 4.

The product of the described procedure is a double coated paper, that is; a paper having two layers of coating on the same side. The two layers of coating may be of the same or different composition, for instance, the coating next to the paper may be a relatively inexpensive composi tion, such as 100 parts of china clay, parts of uncooked starch, 175 parts of water, the parts being by weight applied to the paper and then contacted with steam to gelatinize the starch according to the method described in an application by Donald B. Bradner Serial No. 147,200, filed November 8, 1926, now Patent No. 1,733,524, is-.

,sued October 29, 1929, whereas the coating applied by transfer from ,the finishing surface may be a more expensive composition having some special quality such as color, water-proofness or the like, desired in the finishing coat, for example 100 parts of china clay, 30 parts of casein dissolved in ammonia water, 4 parts of ammonium stearate and 260v parts of water, the parts being by weight. I

In the foregoing illustrative example the coating on the finishing-surface is described as being deposited by spraying in the form of a substantially continuous layer. Instead of a substantially continuous layer of coating, a design, produced for instance'by blocking ofi areas of the finishing surface by means of a stencil, may be deposited on the finishing surface and then transferred to the paper. In place of spraying any other suitable mechanical method of depositing the'coating' may be employed. For instance, the coating may be made up in the form of a paste or ink and deposited by means of a printing mechanism either in the form of design, such as discrete iigures, printed text, pictorial representation or the like, or as a continuous layer, according to the known printing methods. More than one deposit "ofcoating either of the same or diflerent composition or color and either superposed or side by side may be, applied to the finishing surface.

Apparatus for .applying coating in the form of a design and the product are shown in Figs. 2, 3, 4 and 5. Referring to Figs. 2v and 3, I is the cylinder from which coating is transferred to the paper, 21s the axis of the; cylinder, 3 the paper, 4 the press roll, 5 the take-oil'roll, and 6, I and I the means for depositing coating on the cylinder I all as described in connection with Fig. 1. I9 is a travelling flexible metal endless belt which is-suitably perforated with the designs which it is desired to reproduce on the paper, and 20, 20 are 75 then contacted 5 picks up coating from the roll l4 and deposits it on the paper, the roll l4 serving to convey coating from the body, thereof 13 carried in the pan l5.

The'coated paper'is carried by the belt. 9 which travels on the rolls 25 and 26 and is supported 10 by a slate slab Hi. The freshly applied coatingon the paper is spread by the action of reciprocating V brushes l1, l1 whichcontact' with the paper over the slab IS. The paper then passes overthe roll l8 to contact with the cylinder I, In the opera- 15' tion of this apparatus coating is sprayed onto the cylinder I through the perforations 2| in thebelt I 9 and the resulting design is then transferred onto the paper as described in connection with Fig. 1. The design produced is diagrammatically 20 illustrated in Figs. 4 and 5. Referring to Fig. 5,

22 marks the paper web, 23 the continuous coating and 24 the coating which is applied in the form of a design.

The finishing surface need not be in the form 25 of a cylinder as described but may take other forms, for example, an endless belt.

Among materials affording suitable finishing surfaces may be mentioned chromium, nickel and Monel metal. Chromium has been found to afford the most satisfactory finishing surface.

With a highly finished chromium surface, such as may be obtained by electroplating and polishing, commercial water-color printing inks are reasonably satisfactory. Coatings or inks of the type, comprising pigment or dye and casein, for example, 100 parts of china clay, 15 parts casein dissolved in ammonia water and sumcient water to give a thick paste, give good results on finishing surfaces of chromium. Such compositions with an addition of a small amount of soap such as 2 parts of ammonium stearate give good resalts with a finishing surface of chromium as well as with nickel and Monel metal. I

- In the foregoing examples the paper contacted with the coating on the finishing surface was described as carrying a wet or plastic coating upon "its surface. It is to be understood, however, that the contacting paper need not be 'coated. In case itis coated, the selection of a suitable coating composition depends to some extent on whether the coating on the finishing surface is present as .a continuous layer or only parts of I that the coating on the paper be tightly bound I to the paper, and it must also separatefrom the finishing surface after said coating -has hardened. Compositions containing pigment, soap and case in similar to those mentioned above may be satisfactorily used for this purpose. On the other hand, if one or more continuous layers 8f-coating are deposited on the "finishing surface, the

coating deposited, directly on the paper does not come in contact with the finishing surface, except insofar as the coating on the paper may penetrate the coating onv the finishing surface.

0 Another coating composition suitable for deposition on the paper is parts dry china clay, parts of water and 25 parts of uncooked starch the parts being'by weight. This composition is deposited on the paper in any"suitable way and with steam" tov gelatinize the 2,245,045 starch, as described in said application in the name of Donald B. Bradner, Serial No. 147,200, filed November 8, 1926, now Patent No. 1,733,524, and then delivered directly to the chromium fin-' ishing surface carrying the coating to be transferred to the paper.

- The coating maybe deposited on the paper and the paper contacted to the coated finishing surface before the coating on the paper has hardened. Or the paper may be coated and the coating'allowed to harden, e. g., dry, as is done in the normal manufacture of coated paper, and the ing acts as a cement to bind the coating to the paper then rewetted to render the coating plas- .a suitable finishing surface on to paperwhich ,already carries a coating, we will now consider some of the numerous possible variations or modifications thereof. In the first place the paperv delivered to the finishing surface may be coated or uncoated and either wet or dry depending upon whether the coating on the finishing surface is dry or wet. In case the paper delivered to the finishing surface is wet this condition may be the result of rewetting or a freshly formed web of wet paper may be used directly. Also the vehicle or-wetting agent of the coating need not be water but may be any other suitable liquid. Likewise the process is not limited to the use of coatings which harden on drying but contemplates the use of coatings which may be hardened in any other way, e. g., by cooling. It follows that in drying wetcoatings the invention is not limited to the use of elevated temperatures such as are produced by steam heating. Thus the coating may be deposited upon a relatively cold finishing-surface and the paper contacted therewith either before or'after complete or partial drying and finally dried at: ordinary or elevated temperatures. In general, any condition which will provide for adhesive contact between the coating on the finishing surface and the paper maybe employed. Moreover, the invention is not limited to the use of mineral coating compositions; but may employ any other composition which fulfills the following requirements: it must be capable of being hardened in contact with a solid finishing surface{ of being firmly cemented to a sheet or web" of paper; and of being substantially completely removed from said flnish-' ing surface as an integral part ofthe paper without destroying the finish imparted by the finishing surface. For example, a transparent coating composition containing no pigment such as a solution of casein in ammonia water with a small addition of soap and with or without addition of soluble dyestufl is quite satisfactory for use on a polished chromiumsurface. e

The expedient just referred to of delivering a freshly formed and still wet "paper web to the finishing surface advantageously may be carried out in conjunction with the operation of a paper .making machine in which the paper before being paper.

It will be seen invention a substantially continuous coating or layer may be transferred from the finishing surface to uncoated paper or a substantially continuous coating may be transferred to coated paper on which the coating may be either substantially continuous or in the form of a mechanograph, or coating in the form of {mechanograph may be transferred to uncoated paper or to coated paper on which the coating is either substantially continuous or in the form of a mechanograph.

By the term mechanograph as used in this description and in the appended claims, we mean mechanically reproduced text, lettering, decorations or pictorial representations in one or more 1 colors, such as are produced for example by known methods such as by printing, stenciling or lithography, and readily distinguishable under the microscope from photographs or hand paintings. I

As will be apparent, a plurality of layers of coating may be transferred to the paper either in the form of substantially continuous coatings or as mechanographs or both. The coatings may be transparent, opaque, white or colored so that a great variety of combinations and effects is possible. F

It may produce double coated paper as described above by contacting paper carrying a wet coating with a finishing surface upon which a substantially continuous coating has been deposited. Or it may produce a single coated paper by contacting uncoated paper with a finishing surface carrying a substantially continuous coating. Or it may produce paper with coating having an inlaid efiect by contacting paper carrying a substantially continuous plastic coating of a given color with a finishing surfacecarrying a discontinuous coating of a dii'ferent color or combination, of colors in the form of mechano-. graphs. In this case a novel effect is produced inthat the transferred coating is embedded in the coating on the paper and the resulting composite coating is given a cast surface corresponding'to When a highly. polished finishing surface is used in this conthat of the finishing surface.

nection a product of remarkable beauty having the appearance of certain decorated and glazed combinations of coatings in. the form of subcomp'letely dried, is pressed against a drying cylinder such as is used in the so-called Yankee dryer, it being only necessary to provide a drying cylinder having a suitable-non-adhering finishing.

surface, for instance a chromium plated surface, and to provide means for applying a coating to be transferred to the paper web from the drying cylinder. In this case the adhesivein the coatstantially continuous layers and mechanographs on the paper and on the finishing surface may be devised. All of the products so obtainable are. characterized by the fact that the coating transferred from the finishing surface has a cast surface while the parts of the coatinginitially deposited on the paper contacting With the finishing surface alsomay be given a cast sur-" face.

By the term "depositing a fluid coating? we include all methods of applying coating composition alone to the finishing surface, as distinguished from contacting coated paper with the finishing surface.

- By the phrase cementing paper to the coating on the finishing surface weinclude all methods of causing said coating to firmly adhereto the that according to the present corresponding to that of the s As will be apparent, other paper by virtue of adhesive material either on the paper or in said coating or both. Of course if the adhesive in said coating is the cement present,

said coating must be fluid while in contact with the paper and later hardened.-

By the term "fluid coating we include highly viscous pastes as well as liquids of low viscosity.

By the term coloringmaterial we mean to include soluble dyestufis and insoluble pigments whether white or colored.

By the term paper" we include paste board, post card and cardboard, as well as thin paper.

By the term "cast surface we mean the coat ing surface harden'edin contact with the finishing surface, andcharacterized by having a finish similar to that of the finishing surface.

By the term non-adhering finishing surface we mean a surface upon which fluid coating can be hardened and from which said hardened coating can be substantially completely separated without impairing the finish imparted to'it by said finishing surface.

Thi application is a division of our application Serial No. 335,016, filed January 25, 1929, and which matured into Patent No. 2,029,273, January 28, 1936.

We claim:

1. Mineral coated paper characterized by having at least two coatings on the same side of the paper, at least one coating being in the form of a mechanograph, and each coating having a cast surface where exposed.

- 2. Mineral coated paper characterized by hav-' ing at least two coatings, each comprising a mineral filling material and an adhesive, on the same side of the paper, one coating being in the form of a mechanograph, and each coating having a cast surface where exposed.

3. As a new product paper having at least two coatings *of different composition, one of said coatings being in the form of a mechanograph and inlaid with respect to theother, said coatings having a cast surface.

4. Mineral coated paper having a cast surface, characterized by having at least two coatings, each comprising a mineral filling material and an adhesive, on the same side of the paper, one

coating being in the form of a mechanograph and inlaid with respect to the other.

WILLIAM J. MONTGOMERY. DONALD B. BRADNER.

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