US2214641A - Process of producing rotogravure paper and the like - Google Patents

Description

Sept. 10, y1940. l. .1.v MAssEY Er AL f 2,214,641

raocss `or) PnovUc-me no'roomvuns PAPER Aun 'um LIKE 2 sheets-sheet 1 Filed July 17, 21937 INVENT OR.

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La, I

y ATTORNEY.

l 51st. 10,1940. J. MAssEY E-r Al. 2,214,641

" PROCESS 0F PRODUCI-NG ROBIOGRAVURE PAPER AND THE LIKE 2 Sheets-Sheet 2 Filnd July 17. 1937 v v JDSSSSG N251@ a m Patented 10, y.

, Y "2,214,641 t cass vorl 'raoDUoiNa no'rocmivrms A PAPEBAND THE LIKE c Peter J. Massey, nivel;- Forest, nl., annifr'ea T; Gardner,v Appleton, andv Albert F. Piepenburg, Combined Locksfwis., assignors, bymesne assignmentsg to Combined L'oeksPaper Company,l 'j

j Appleton, Wis., a corporation of Wisconsin Application July 17, 1937, serial No.l 154,140

Claims. (Cl. Sib-40) This invention relates to,y theproduction lof paper adaptedv for rotogravure printing or for uses having similar requirements. f

In making paper for rotogravure printingv it is I necessary to give' thejprinter'a sheet of. paper with asA perfect a plane surface `as possible. ,If -thepa'p'er maker could' produce a perfect plane this would lbe 'the ideal for'the printer of roto- `gravure paper. Thisl would permit perfect'contact with intaglio cylinderand reproducesall detalls of image engraved thereon.` The "values would be indirect ratio'to the' papers approach tothe true plane'. [The principal value of rotogravure is its close resemblance, through optical u illusion, to a continuous tone picture, alarge portion of which value issecured through'they surface resistance of the' paper by giving the inkfan opportunityto spread before drying instead of setting by absorption.-

'80 Therefore the industryreduires a sheetwith a smooth plane surface, having a skin or surface hardeningy to -give thedesiredreproduction and vyet -ofr such character as to retain its printing opacity and Vcolor without v,blackening and the strengthto withstandhigh speed press operation.

A In the past, the paper mills have attempted to produce these qualities in paperfor rotogravure by various methods of machine operation. Some mills calendered the sheet very high butthe deep $0 pits 4i'rom wire, felt, etc., could be seen inthe sheetfand werenotironed out, I' Other mills tried to improve the surfaceby aminimum offelting and using smoothing rolls and breaker j'rollsv to -try to'get aplane surfaces' Thispaperused'by al the printer was still unsatisfactory because while the sheet appeared improved as'to its surface it did not print smoothly; didnot reproduce the full tonal values; required more ink and caused sh'ow through.V 'Still othersftriedto develop this plane 40 surface and skineilect by running a sheet of paper through a size tub Aand with a'high moisture content'into the machiner calender stacks.. This developed the trouble` of =blackened and crushed paper, off-color 'papei streakiness, lo'ss of opacity `rand very unsatisfactory` running condi?.

nous;v f AOne of fthe principal objects of the present in- 'ventionis to provide an apparatus for `and meth-` od vof producing paper which'will fulfill allofthe requirements of rotogravure 'printing and of accomplishing thisas a continuous operation on ai paper making machine with-a minimum modification of the machine and withtheaddition of comparatively few and entirely practicalL 'supple' u mentary or modifying instrumentali'ties.

The present invention produces ay smoothsheet of vpaper-which has -hardened skin surfaces, the surfaces, presenting a glazed or glossyeffect similar toy Cellophane but the sheet Astill 'retains its capability yoftaking ink, the property of absorb- 5 ing' the ink whne permitting sp'read or @morne-i velopment and has opacity, color, strengthand minimum showy through. Furthermore, the blackening eifect so levidentina sheet that confo tains a high moisture content and has been high- 1 c ly calendered isavoided.

n-l A theyv may be added at the fan pump, maybe applied to the web as it is beingformedon the-wire by means of the dandsI roll, may be applied to the sheet at the smoothing rolls, or maybe liricorporated therein at some point in the battery of ALdriers as with regular size tub or breaker rolls and in water box on calender rolls.

Whatever may be the particular, place yor point 30 of incorporation the present invention does pro-v pose to form a web of paper on the forming wireY of ay paper making'machine in the usual manner, then pass the sheet ybetween the presses, then run it through one or more pairs, of, smoothing rolls, 35 then through an'ext'endedbattery of driers with or without breaker rolls incorporated therein until it is dried,y to bonedry at the last drying irulnuv -A At'this point Ithe Wireside of the sheet is 'sur- 40 face moistenedI and this besty accomplishedby sweating the exteriory surface of' the last drier Sweatingthe exterior surface'of the v'last rdrier drummay be conveniently effected by running'a 45 controlled amount of cold Water into 'f the inte-- rior of thel druml and subjecting theyexterior thereof to a steam spray 'or shower. c y y As the sheet lof paper leaves the last drier 'its topside is surface moistened and this may be con'- 50 veniently accomplished by running the top side of the sheet under the usual spring roll and sweating'- the exterior surface of this spring rollA in *the*l same manner as on the last drier.

After running under the springv roll the sheet-of 55 y for 'similar'usaga l. paper is calenderedthat is, it is passed between the calender rolls which make up a tier or stack. To accomplish the purposes ofthe present invention` the sheet must be calendered in a special manner, as follows: The sheet is calendered by passingl it through two nips of unheated top calender rolls. Next it lis hot calendered or hot ironed bypassing it 'through two nips of steam heated calender rolls, the temperature o f which is properly controlled. Before the wire side of the sheet lisy passed between the rst niplof the steam heated calender rolls it is subjected to the action of a steam spray. Before the sheet passes between the second of the two nips'` of heated calender rolls its top sldeissimilarly steam sprayed. Thereafter the sheet is run between a series of unheated calender rolls and is then ing the sheet and then ironing orcalendering the vsheet with both unheated and heated rolls, the

action of the hot rolls being y supplemented lby steam sprays'.

the sheet is dampenedjust su'mciently to respondto the calendering or-ironingto take the hard skin orglazed effect while -leaving the body! of the sheet so constituted and characterized as to retain in the sheet opacity, color, correct ink reactive properties, and the other characteristics which adapt it for Arotogravure printing or other objects and advantages reside in certain novel` features of the construction, arrangement and combination ofpa'rts which will be hereinafter more fully described and particularly 'pointed outfinthe appended claims, reference being had to the accompanyingdrawings formf ing a part of this specification, and in which:`

AFigure v1 is a fragmentary diagrammatic view illustratingY the instrumentalitiesj ordinarily employed for conditioning and delivering the. stock tothe forming wire of ak paper making machine;

f Figure 2 is a similar view showing part of the paper making machine comprising the head box,

forming wire, and one or more presses;

Figure 3 is a similar diagramamtlc vie'w showing h o'ts1 the sheet is carried through the smooth- -ing rolls andan extended battery of driers; l 4 v y 'Figure 4 is' a fragmentary diagrammatic view showing the last two driers, the calender stack and reel, and ililustrating diagrammatically how -the'last drier is sweatedand the provisions made for steam treatingthe sheet andhot calendering it in the calender stack; f

Figure 5 'is' a fragmentary lview ln end elevation and on a somewhat enlarged scale showing the steam heated and adjacent rolls of Lthe calender stack Aand associated instrumentalities; Figure 6 is va fragmentary view in elevation showing'-the rotarneter'employed to indicate the amount of water supplied to the lastdrier 4and facilitate regulation lthereof; and

' Figure 7` is a fragmentaryview partlyin endly l v trunnions to connect with the sprayinside of theA` 1 drum 46. `vTheiotherJtrunnion;is utilized to reelevation and partly in section illustrating the I spring roll. f

Referring to the drawings` and more particuand 2, to a pipe 26 which receives the liquid from a collecting or` Water .pan 21 underlying `the forming Wire. take of a fan pump 28 which delivers the stock Athrough a'pipe line 2 1' (see Figures 1 and 2) to the screen V28' from whence it is conveyed through the pipe line 29 to the head box 33.

-The head box 30 delivers the stock to the forming wire 3| adjacent lthe breast roll 32 around which and 'the couch rolls 3'I the other guide and stretch rolls, the forming wire runs in the usual manner. A dandy roll 35 is co-operatively related. y to the forming wire.

These several conventional,instrumentallties of a paper making machinev have been-diagrammatically illustrated `'and briefly referred tuinasmuch as the present Vinvention contemplates y v vincorporating the 'special material in the stock at It has been found that with this treatment a number of pointsf Forexample. it'rmay be added to the stock. at'the beater I0, supplied thereto atlthe fan pump .28, or applied to the web by the dandy roll 35 'on' thei'orming wire. It

This pipe 26 connects to the inmay be aflso added later o n in the handling of n the sheet in the machinaas before indicated.

The sheet or web W formed on the forming wire 3| is carriedthrough the iirst and second presses designated generally at 96 and 31.'

. Eachof these presses has an upper roll 38and a cooperable roll 39. A ,feltj'40 co-acts'with. each roll 39 and contacts the wireside of the sheet as it passes through the nip' of the press rolls. Suitable Aguide rolls y4I are providedfoneach felt. kLeaving the second press the `web is carried through t at least one` pair vofstnoothing rolls designated generally lat42"(see Flgure).v Each pair of smoothingrollscomprlses an uprolls, `for 'example they upper roll, has ya hardV vmetallic surface,usually chromium plated, while the other has its surface at least, constituted ofA moisten the 'wire sideof the sheet orwebatl the last drier drumwhich is designated Vat' 46 (see IFigure-l.v Inaccomplishing this the exterior surface of the drum is sweated `or .caused to `collect moistureorcondensate on its` exterior;k

'I'he sweatlngof the drum may be `conveniently y effected by controlling its temperature and tsubjecting its exterior .to "a v steam shower orfSp'ray; The best method we'have found for controlling the moisture is to supplya controlled amount of cold water sprayedat knowntemperaturen they interior of the drum. For this. purpose a water supply pipe 4l is'v extended' throughone ofthe move an excessamount of water` in the usual way. 'I'he cold water contacting the inner 'wall of as! per rollj43 ,and a .lowerf roll 44. yOne ofthese l l fangen vdrum between 70 and80 Fahrenheit. To facilitatethe maintenance of this drum temperature a rotameteris incorporated inthe supply pipe 41 and` as shown in Figure 6,' may comprise simply .A

a graduatedtransparent or glass tubey suitably connectedby fittings or couplings 49 to sections of the water supply pipe ,45. A tapered: plug 50 floats vin, the transparenttube 48. By means ,of the rotameter'the operator` determines the position of the plug which is effective. to maintain the proper drum temperature. A steam shower pipe 52 ysupplied with exhaust steam at one pound pressure parallels the descending side of Vthe drier drum 45 and has a row of periorations forming steam jets 53, the jets impinging on the surface-of the drum and as this surface is cold, the steam is condensed and the drumi is properly sweated.

As. the sheet leaves the last drier drum 4l it passes under a spring roll 55. The springroll 55 is also chilled by cold water supplied and exhausted lthrough its hollow trunnions in order shower as in the case of the drier drum.

, calender lstack 58. This stack is made up of a to sweat its surface and is equipped with a steam In this lway the top of the sheet is adequately surface moistened at this point. f

Leaving the spring roll the sheet-passes to the vertical tieror stack of calender rolls of conventional construction except that two ofthe rolls designated at 51 and 58 are steam heated. The other rolls are not heated in accordance with the usual practice. lFrom Figure 4 it will be seen that the sheet in passing to the calender is first passed through two nips of two unheated calender rolls. It is next passed through the two nips of heated rolls and afterwards through the nips of unheated rolls. For the purpose of heating the e webor sheet of paper the action of a steam spray 51 as it passes between' thenip of the calender rolls 51 and '58.

To obtain best results with a paper making machine of .the character shown, vthe steam supply to the hot calender rolls is under eight pounds pressure atea temperature of 250 Fahrenheit.

Suitable regulators are-provided for this purpose.

The temperature of the last drier drum and also of the spring roll 55 is maintained between and 80 Fahrenheit by suitably controlling the supply of cold water thereto, as for example f inthe manner described in connection with the drier drum 46. l

The' paper sheet produced by the present invention has strength, color,` opacity and both surfaces thereof are hard skinned, glazed, smooth f. and substantially planar.- The sheetis admirably adapted for. rotogravure printing. It has the strength to withstand high speed press operation. It will take ink in suchmanner that the ink adheres thereto with slow and slight absorp-y tion thereby permitting spread or color development resulting in a close resemblance to a continuous tone picture and this with minimum show through. Blackening or f streaking is avoided., l l

An exemplary formula which may be employed withgood results is as follows: Y

o Parts by weight Starch 10k Clay' y 100` Steal-in I 5 r G11uco'se l n 1 "Ifota1' .116

1534.8 poundsgof this surfacing material ls Sed pery oney hundred pounds of `paper making materials.` f

While we have shown and described one apparatus in which the invention may be embodied and one wayiny which the method may be prac- .v ticed it is to be understood that the particulars l of description and illustration are exemplary rather than restrictive and that various changes and variations may be resorted to without department from the spirit of the invention or the scope l of the subioined claims.

'I'he invention claimed is: 1. The herein described process of producing rotogravure yprinting paper on a paper-making vmachine having a series of drier drums, a calender stack with unheated top rolls, heated intermediate rolls and unheatedbottomrolls, and a .spring roll between the drier rolls and the calender stack which comprises forming a sheet, in-

corporating a composition including a' loading material andastarchymaterial in the sheet prior to itstravel over the last drier drum, surface moistening the wire side of the sheet at the last drier drum, surface moistening the top side of lthe sheet at the spring roll, calendering -both sides of the sheet between the unheatedtop rolls of the calender stack, steam spraying and hot calendering both sides of the sheet in the next yheated rolls of the calender stack, and then calendering both sides of the sheet through the remaining unheated rolls of the calender stack.

v 2. The herein described process of producing rotogravurefprlnting paper on a paper-making machine comprising driers, and a calender having heated and unheated rolls which consist in forming a sheet, incorporating a composition including aloading material and a starchy material in the sheet before it reaches the last drier, surface moistening both sides of the sheet as it `leaves the driers, calenderingboth sides of the sheetwith unheated rolls, subjecting both sides ofthe sheet to steam sprays and to hot calendering with heated rolls, and then again calender-ing the sheet with unheated rolls.

3. 'I'he herein described process of producing rotogravure printing. .paper on a papemaking machine having a series of drier. drums, a spring roll, and unheated and steam-heated calender rolls which comprise forming a sheet, incorporating a composition including `'a loading material and a starchy material in the sheetbefore it reaches the last drier, sweating the exterior sur-V face of the last drier drum to surface moisten the wire side of the sheet, sweating the surface of the' spring roller to surface moisten the top side of the sheet, passing the sheet through twoy nips of unheated calender rolls, then passing the sheet through two nips of steam-heated calender rolls after first steam spraying the wire side and ythen the topside ofthe sheet, and finally passing the sheet through a series of unheated calender rolls. f

4. The hereindescribed method of producing rotogravure printing paper which ycomprises forming a web of paper, incorporating a composiywith unheated rolls, subjecting both surfaces of the web to steam sprays and hot ironing both surfaces thereof, andfinaliy ironing both surfaces of the web again with unheated rolls.

5. The hereindescribed process of producing rotogravure printing paper which comprises forming a. sheet and incorporating in the sheet a composition including afioading material 'and a starchy material required toproduce thede- -sired surface in the resulting sheet, subjecting the 4sheet to rolling pressur ,-drying the sheet to approximately 95% bone dry, surface moisteningy both wire and top sides of the sheet, calendering both sides of the sheet with-unheated rolls,

subjecting both sides ofthe sheet to steam sprays v and hot calendering both :sides thereof,V and ,n

nally calendering bothfsides of the sheet again with unheated rolls. l i i v i y PETER J. MIASSEY.v

' ALFRED T. GARDNER.

ALBERT F. PIEPENBURG.

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