Патент USA US2130530код для вставки
Sept. 20, 1938. 2,130,530 J. FLETCHER ' COATING OF FIBROUS SURFACES Filed Oct. 5, 1935 ‘ k. \\ .. b5, . w“0 G 6numb: owpwux. ‘ \W 0 ,G 0 y m\.w K/QmMr?.1\ n0 w\R‘90@ \w Q . . ., 0Q 265 .Q 2v“N 5.5, OwmWwwI ,.n-wbmwwl, , V, v ,.m\2,35 siNM... .Qwhw . "R. Q .m ‘. MN ,3 , \ . .‘ Q ,,. . , 0M W my .M?v A n» \M . ,A . I N@ d M 7G vQ . .. w 5N.MN\ .a .1 . My Patented Sept. 20, 1938 ' 2,130,530, UNITED STATES PATENT OFFICE _ 2,130,536) ooamo or muons summons John Fletcher, Kenmore, N. Y., a-ssignor to Plas tergon Wall Board Company, Bu?'alo, N. Y., a corporation of New York Application October 5, 1935, Serial‘ No. 43,738 11 Claims.‘ (01. 91-40) This invention relates to the coating 01' ?brous surfaces or paper sheets, and particularly to the coating of the paper web leaving a'paper making machine. 5 ’ In the accompanying drawing, I have illus trated diagrammatically an apparatus for apply ing a water dispersion of coating material to a travelling paper web, as the web leaves the dry ' - An object of the invention is to provide an im- , ing cylinders or rolls of a paper making machine 5 proved method of applying a coating to a ?brous surface or sheet, with which the penetration of the coating material into said surface or sheet will be relatively slight, with which a ?brous sur lO face may beocoated in a simple, rapid and in expensive manner, with a minimum of handling of the object to be coated, and with a minimum of manual labor. , ‘ in order to illustrate an important embodiment of the invention. ' Lacquer emulsions‘or lacquer dispersions in the water phase, have recently been made ‘available for industrial use as also water dispersions of 10 various other coating materials of the type which harden upon the evaporation of a solvent, among "which may be mentioned nitro cellulose lacquers, ' Another object of the invention is to provide 15 an improved method of coating a ?brous sheet, such' as paper, with which the coating material will remain largely on the surface of the sheet, synthetic resins, natural fossil resins and rosin. ' A description of lacquer emulsions or water (115- 15 persions and their preparation, composition and use has recently been published and made avail- _ with which the ?nish as to gloss or ?atness may be varied within limits, and which may be easily able to the trade by The Hercules Powder Com pany Inc. of Wilmington, Delaware, in a booklet 20 and inexpensively performed. entitled"‘Lacquer Emulsions”, and copyrighted in 20 Another object of the invention is to provide , an improved method of coating a travelling paper sheet or web, such as the web leaving the drying rolls or cylinders of a paper making machine, and 25- with which the coating may be applied ‘to the web and hardened in a rapid, simple and inex pensive manner ‘while the web is travelling and then be immediately wound or otherwise disposed of. 30 . - - A'fu'rther object of the invention is to provide an improved. method of coating and coloring a ?brous sheet, such asa paper sheet, with which uniformitygin the coating and coloring may be obtained, with which the coatingand coloring 1935 by The Hercules Powder Company Inc. Referring particularly to the drawing,’ the in vention is illustrated as it has been successfully applied to a paper making machine for the coat ing of the travelling paper web leaving the paper 25 making machine. The travelling web III of fresh ly formed paper, after passing over a desired nmnber of drying cylinders or rolls II, is con ‘ ducted over "an idler cylinder I! to the upper end of a. calendering device or unit l3. This 30 calendering device includes a, series of ?oating, ‘ calenderin'g cylinders ll, l5, l6, l1, l8 and I9 which ‘are arranged above one another, guided for vertical movement in?oating contact with one another, and yieldingiy urged in ‘contact with 35 35 may be performed while the sheet is travelling, and which requires no complicated or elaborate \ one another under heavy pressure. apparatus. , ~ Such a ~ calendering device is a common attachment to or I Another object pf the invention is to provide an a part of paper making machines for calender improved method of coating paper and similar . ing the web leaving the drying cylinders. ‘ 40 sheets with 'a water dispersion of coating sub ‘The web' Ill passes alternately around these 40 ‘ stances, such as nitro cellulose lacquers, syn thetic resins, natural fossil resins and rosin. Anotherobiect of the invention is to provide improved apparatus‘for: applying water disper 45' sions of lacquers, resins, resins and other coat ing materials which harden by evaporation of solvents, to ?brous objects, such as paper webs and sheets, and which will be- relatively simple, inexpensive, ‘and easily incorporated in the usual , 50, paper making machines. Other objects and advantages will be apparent from the following description of an embodiment ‘ of the invention,‘and the ‘novel features will be particularly pointed~out hereinafter in connec 55 tion with the appended claims. ,' calender rolls I‘ to l9, and then passes from the lower cylinder or roll ‘l9 to the top cylinder 20 01' a second calender device or unit 2|. As, the web l0 passes around the calender rolls in the unit IS, the opposite faces of the web are suc~ 45 cessively moistened by water applied to the cylin ders or rolls l5 and II which engage opposite faces of the "web, the application of moisture to these rolls or cylinders being obtained by water boxes 22 and 23, each of which is ?tted against 50 a side of a cylinder, with the cylinder forming a side wall ‘of the box, the boxrunning approxi mately for the full length of the cylinder. This is common practice in the calendering devices of paper making machines. ' ‘ '55 2,130,530 2 iected to pressure in the unit if, as usual here tofore, the web passes through the second unit. 2l in which the web is subjected to further pres sure betweenathe cylinder rolls of that second The second calender. unit 2i includes: in ad dition to the top cylinder 20, additional cylinders 24, 2|, 2‘, 2'1 and 28 all-arranged as usual in paper making machines in‘ superposed, ?oating unit, the web being heated further as it passes aroeund the rollers 2i and 20. The heated web leaving the roller 26 passes in contact with the contact with one another, and under high pres sure on one another. The web ll. after passing over the top calender roll 2., passes alternately around the lower rollers 24 to 28 of that unit, roller 21, which forms one side of the water box 31 and then passes to the top roller 2| of another‘ in which the water dispersion of the coating ma- , calender unit II. The web, after passing around terial is placed, and the roller 21 takes up a ?lm the top roller 2| of this third unit 8|, passes of this coating material from the box 31 and alternately around the successive and lower rolls carries it into contact with the web ill on one face ‘L12, :3, 34 and 35 of that unit, and then is thereof, excess coating material of the film being squeezed out by, the pressure between the rollers 26 and 21 and running back into the box 31. The 15 coated face of the web then passes between the rollers 21 and 28 where it is subjected to pressure to force the coating compound into further con tact with the web ?bres, and then this coated face is exposed to air as it passes around the roller 2| and travels to the top of the third calender unit conduc over an idle roller 30 to the winding or cutting mechanism, as usual in paper making machines. These three units it, 2i and 80 thus represent three usual calendering units through which the web is °®mmonly passed successively ' inleaving the-drying cylinders before it is wound , 20 or otherwise disposed of. In the unit 2i, two of the rollers or cylinders 25 and 26 intermediate the top and bottom rollers . ll. ' . , As this freshly coated web leaves the roller 21 are heated in any suitable manner such as by steam, and similar rollers 32, and 33 in the unit Ill may also be similarly heated. A water box 31 is disposed along the roller 21 which is below and passes in contact with the air to the third calendering unit It. a considerable portion or ‘all 25 ‘calender unit 2i, so as to apply a liquid coating to the cylinder 21 and through it to one ‘face of freshly coated web in this zone has a temperature above room temperature, and the escape of steam and moisture from the web when so ex 30 posed to air aids in carrying oi! the volatile sol vent. with the result'that by the time theweb ' reaches the top roller of the third calender unit, the coating has set to some extent so that it is of the volatile solvent of the coating is driven off _ the heated rollers 25 and 2| in the intermediate _ by evaporation, it being understood that the _ ~30 the travelling web iii. In this water box 81, of which the cylinder 21 forms one side wall, I place the water dispersion of the coating material, and thus as the cylinder 21 rotates in the direction of the arrow, it will carry some of this coating ma 35 terial with it and transfer it to one face of the' travelling web it. ' l . . I no longer tacky. ' ‘ I _The water-dispersion of the coating material tween the successive rollers thereof, where it is subjected to a calendering operation of pressure may be prepared in any desired manner and of any desired material, but among such materials and heat, during which'ang remaining solvent 40 which are particularly 'usefullin the coating of and the moisture in excess of that desired in the ', paper may be mentioned the nitro cellulose lac quers, synthetic resins, natural fossil resins, rosin, ?nished web is driven off, ‘and a smooth calen particularly the rosin which is the residue from Ydering surface is provided on‘ the coated web. the distillation of turpentine from turpentine sap, The web then passes over the roller 38 to the and also oil and water soluble termite and fungus winding roller or the, cutting machine as usual '45 35 This partially dried or'hardened coated web is then passed through the calender unitgll, be 45 resisting materials, as well as water dispersions 7 in paper making machines. In‘ the foregoing description, it will be under ‘of insoluble termite and fungus resisting mate stood that the ‘coating may be applied vthrough the water box of the usual calendering mecha tar products and certain ‘zinc salts. Various \ nism of paper making machines, without any in mixtures of these materials to make up the coat crease in equipment or any additional handling ing compound, in water dispersion phase, may be. of the web, but if it is desired to coat both faces of the web, an additional calendering unit should used when desired.‘ . -‘ . i preferably be provided, so that the opposite faces The water dispersion or emulsion of the coat ing material which is placed in the water box 31, of the web may be successively coated and then may also contain any desired coloringmaterial, a'drying and calendering ?nish given to the web. It will be understood that the apparatus illus either of the water or oil soluble type. The pre trated diagrammatically in the drawing, and ferred dyes are-soluble in coal tar solvents, or in ' rials. Flmgus and termite resistant materials are well known, and include arsenic compounds, coal l solvents which are immiscible with water, or with * pigments in suspension, so as to impart to the coating any desired color. In the operation-of this coating apparatus, the paper web II which leaves the drying rolls or cyl ‘inders ii ofthe papermaking’machineisaofa temperature materially’ above room temperature, and as it passes through the, calendering unit it, the opposite faces of the web are moistened ,by water contained inthe water boxes 22 and 23. At the same time the web is subjected to consider 70 able pressure as it passes between abutting‘ rollers of the unit II‘. In the making of paper, it is nec I ‘Is essary to dry the web quite thoroughly through out, and then to moisten the‘ faces thereof in order to calender the surfaces of the web. After being moistened on its faces and‘ sub-v .which constitutes part ‘of a well known paper making machine, maybe modified within the prin ciple of this invention, and the improved method of coating may be applied to flat sheets by per forming similar operations on the web, such as, for example, by ?rst moistening the face of the web to be coated, then calendering it, applying a 65 water dispersion of thecoating material thereto, allowing the volatile solvents and part of the moisture to evaporate, and then further calen dering or drying the coated sheet. I have found that by ?rst moistening the web 76 before the water dispersion of the coating ma terial is applied thereto, there is less penetra tion of the coating material into the ?bers of the sheet, also that the heating of the web or sheet before the water dispersion of the coating 3 2,180,530 material is applied is advantageous, in that the tion of nitro cellulose in solvent. Such a solu heat of the web quickly eliminates the volatile ‘tion dries by evaporation of the solvent, deposit solvent of the coating material in a steam atmos ing a uniform continuous ?lm, and with the addi phere, and also part of the moisture ‘of the coat tion'of resin a glossy ?lm. A ?occulation of the ing, so that less travel of the web and less expo sure of the web to air is required before being further calendered and dried. The driving oil? solids-occurs on the coated sheet or web when a water phase dispersion of nitro cellulose in sol vent is used as the coating material. ,The evapo ration of the solvent and the water ?occulates occurs while the web is travelling‘ between the. the solids and this ?occulation deposits on the of the solvent in an atmosphere of steam which 10 units 2| and 30 tends to produce a mat ?nish ' ‘on the web, which is particularly valuable as a primer coat or ?nish to receive paints, particu larly water paints. If a higher gloss on the coated ?bers. ' ' This coating. has a mat-appearance and is particularly suitable for its intended use as a priming or'base coat for, ?nish coats of clear face of the web'is desired, the preliminary mois- ._ Jlacquer- or nitrocellulose in solvent. 'Nitro cellulose dispersion in the water phase 15 15 tening of the web before the water disperson of _. the coating material is applied is eliminated or has a milky appearance. the amount of preliminary moistening reduced. It will be understood that various changes in' the details, materials and steps which have been The preparation of’ithe water dispersion of vari ous substances is now generally understood and 20 is explained in the booklet entitled “Lacquer , Emulsions” hereinbefore referred to. The prep aration of such an emulsion may, however,‘ be brie?y described as follows: The ?rst step in preparing a lacquer emul 25 sion is to make up the base lacquer. The compo sition of this base lacquer depends upon the use ' herein described and illustrated in order to ex plain the nature of the invention, may be made 2,0 by those skilled in the art' within the principle and scope of the invention as'expressed in the . appended claims. I claim as my invention: , 1. The method of coating the ?brous surface of a sheet-like object, which comprises pre-wet- , to which they finished lacquer emulsion is to-be ting said surface with water, applying to the ‘put. said wet surface a coating of a water dispersion of a nitrocellulose lacquer containing .a solvent ' The lacquer base and water containingthe emulsifying agent are then mixed together, and agitated to obtain a uniform mixture which can be put through an emulsifying machine such as the Premier Colloid Mill or The Manton-Gaulin Homogenizer. However, many other machines of 35 similar type are available, which‘ probably would ‘ give comparable results. The ratio. of lacquer phase to water phase vwill ordinarily vary be tween 2 parts of lacquer to 1 part of water and 3 parts of lacquer to 1 part of water.‘ In gen 40 eral, the lower the percentage of water used in the emulsion, the higher the" viscosity of the ?nished emulsion will ‘be. In making all emul sions and especially those with a low percentage for the nitrocellulose, then exposing the coated 30 object to a drying, humid atmosphere su?icient to eliminate the solvent without substantial elimination of the water and deposit the nitro cellulose lacquer solids on said ‘surface, and then drying the object to remove the water. 2'. The improved method of applying a coating to a surface of a ?brous object which comprises moistening the surface of the object with water, applying to the moistened surface a coating of a water dispersion of a nitrocellulose lacquer, drying the coated object until thelcoating passes the tacky stage, and then further drying and‘ 40 calendering the‘coated surface to produce a mat of water,‘it is best to use a procedure known - like ?nish on the coating. 45 as “Seeding”. By this procedure about a quarter of the lacquer base is ?rst dispersed in the en tire water phase and this mixture is passed ' through the homogenizer to form a dilute emul sion. ‘To this is then added the remaining three"50 quarters of the lacquer base and the complete mixture again is emulsi?ed. The size of the emulsion particles is decreased by repeated passes. 3. The improved method of applying a ‘coating, 45 to a surface of a ?brous object which comprises ,moist'ening the surface of the object with water, heating the object, applying to the moistened and heated ‘surface a coating of a water .dispersion of a'nitrocellulose lacquer, drying the coated ob Ject until the coating passes the tacky stage, and calendering the partially dried, coated surface to through the homogenizer. One or two passes is ~ produce a mat-like ?nish on said coating. 4. The improved method of. coating a paper usually sumcient however. In making up a pigmented lacquer emulsion' web which comprises imparting translation to» 55 55 on the Manton_-Gaulin, the following technique is said web, heating and moistening the face of The baille ring on the second‘ ' said web to be coated, applying to the heated and stage homogenizer should be left out and a moistened face of the moving web a coating of a properly supported 200-mesh screen placed over .water dispersion of a nitrocellulose lacquer, dry the outlet of the second stage homogenizer. All ing the coated web‘while in motion until the 60' of the water phase should be added ?rst with only - coating passes the tacky stage, and then calen a small part of the lacquer phase, and pumped dering the coated surface with heat to dry the through the machine; the only pressure should coated web and produce a mat-like ?nish on recommended. ' be that built up by the resistance of the screen. 65 The remainder of the lacquer phase is gradually added during recirculation. - When 'it is all added, the ?rst stage pressure‘ is increased to 2,500 pounds, and 1,500 pounds is put on the second stage. The emulsion is then passed 70 through the machine two or three times.‘ The ' 5. The improved method of coating a surface 65 of a ?brous object which comprises applying to said surface while in'a heated and moist condi-, tion, a ‘coating of a water dispersion of a nitro same technique may be used on the unpigmented cellulose lacquer, drying the coated surface until the coating passes the tacky stage, and then 70 calendering the coated surface with heat to fur emulsions though they are usually made without the screen and with the second stage ba?le ring ?nish on the coating. in place. - ‘ 75 the coating. There is a distinction in the drying ofa solu ther dry the coated web and produce a mat-like ' 6. ‘The improved method of coating a paper web which comprises applying to the hot, moist 4 web leaving the drying cylinders of a paper mak ing machine, a coating of a water dispersion of a nitrocellulose lacquer containing a volatile sol-‘v vent for the nitrocellulose, passing the.- coated web in contact with air to partially eliminate the volatile solvent in said coating and carry the "coating on the surface past approximately the tacky stage, and then calendering and further drying the coated web to produce a mat‘ ?nish. L10 on the web. . persion of a nitrocellulose lacquer and contain ing intermixed therein a termite and fungus resistant material, saiddispersion containing a volatile solvent for the nitrocellulose, then pass ing the hot coated web immediately in contact with air to partially eliminate the volatile sol vent in said coating su?iciently to quickly carry the coating on the surface past approximately the .tacky stage, and then further drying the coated web. . '7. The improved method of coating a paper ' 10. The improved‘ method of coating a paper web which comprises translating said web while heated and moistened on that surface which is to be coated, applying to the moistened and heat the traveling, hot, moist web leaving the drying 15 ed surface a water dispersion of a nitrocellulose lacquer, exposing the travelling coated web to a dryingoaction until the coating passes approxi mately the tacky stage, and then calendering the travelling coated web with heat to harden and 20 dry the coating and produce a mat-like finish thereon. » 8. The method of coating a paper sheet which comprises coating a face of the sheet which, be fore coating, contains substantially more mois 25 ture than it will retain in normal atmospheric 10 web which comprises continuously applying to cylinders of a paper making machine, a coating of a water dispersion of a nitrocellulose lacquer 15 containing a volatile solvent for the nitrocellu lose, then immediately passing the hot coated web in contact with air to quickly and at least par tially eliminate the volatile solvent in said coat ing sumciently to carry the coating on the sur 20' face past approximately the tacky stage, and then further drying the coated web. 11. The improved method of applying a coating to a surface of a fibrous object which comprises coating a face of said object which before coat 25 conditions, with a water dispersion of a 'nitro ' ing contains substantially more moisture than cellulose lacquer containing some volatile solvent ' it will retain under normal atmospheric condi for the nitrocellulose, and immediately exposing the coated sheet to a drying atmosphere at a 30 temperatureoabove normal room temperature to eliminate the solvent and deposit the lacquer solids on said surface, and then eliminating the remaining water from said deposited coating. 9. The improved method of coating a paper web which comprises applying to the traveling, hot,‘ moist web leaving the drying cylinders of a paper making machine, a coating of a water dis tions, and while at~-a temperature substantially above normal room temperature, with a water dispersion of a nitrocellulose lacquer containing 30 some volatile solve?tfor the nitrocellulose, then immediately exposing the hot coated sheet to ‘ contact-with air to partially eliminate the vola tile solvent in said coating sumciently to carry it past approximately the tacky stage, and then 35 further drying the coated object. - ' JOHN I'LE'I'CHER.