US1665611A - Method of and apparatus for making gummed paper - Google Patents

Description

April 10, 1928. 1,665,611

W. H. SMITH ET AL METHOD OF AND APPARATUS FOR MAKING GUMMED PAPER Filed Jan.26. 1926 W m INVENTQRS ,ZZWM? r ATTORNEY Patented Apr. 10, 1928.

UNITED STATES PATENT orrlca.

WILLIAH HENRY SMITH. AND ALBERT srnwanr waas'rnn, or OTTAWA, oN'rABIo, CANADA, ASSIGNORS 'ro AMERICAN BANK NOTE COMPANY, or NEW YORK, N. 1., A

CORPORATION OF NEW YORK.

METHOD OF AND APPARATUS FOR MAKING GUMMED PAPER.

1 Application filed January as, 1926. Serial .No. 83,781.

Our invention relates to a method of making gummed paper and an apparatus used in the practice of said method, and more parthe solvent or other vehicle for the gum or other adhesive being by adrying process, which causes the hardenlng or crystallization of the gum or other adhesive material.

The contractionof the material of said body or its shrinkage during the hardening or crystallization results in the development of stresses at one surface of the paper which causes the paper to curl.

While for some purposes the curling of gunnned paper is not objectionable, when a strip or web, or-large sheets of such paper are to be printed upon, the paper, In order to permit its being properly fed in relation to the printing couple, and to permit the making of a clean impression, should be flat, in order to secure quality in the' printed product. In other words, non-curling paper is required in the better grades of printing when the impressions are made upon previously gummed pa er. v- I In work of this kind, it has heretofore been the practice, particularly when printing on a paper web, to make the impression first and gum the opposite side of the sheet following the making of the impression. While this practice obviates those difficulties during the making of an impression resulting from the use of curled gummed paper, in the subsequent cutting or perforatln of such printed and gummed paper, difiicu ties are encountered by reason of the tendency of the paper to curl, these difiiculties resulting in a slowing down of such operations and the frequent spoilage of work. It has heretofore been the practice in order to avoid the above difliculties, to use certain materials such as red oil in the solution to weaken the bond between adjacent crystals of the body of the adhesive formed by the elimination of the vehicle from the adhesivt and thus lessen the stresses due to the con-1y tract ion of this material to an extent tomaterially lessen, if not to entirely avoid, 'dis- 3' tortion of the paper or its'curling lt' has;

also been the practice to mechanically break down the bridge of crystals after the vehicle has been removed from the adhesive, thus relieving the paper from -the stresses and permitting it to flatten out. a

The addition of oil. to the adhesive tend to weaken its bonding pro el-ties when moisture is restored to the adiesive for making it tacky, and the mechanical. breakage'of the crystalline structurefofjthe dried adhesive'not only involvesa re-handling'of the paper, but-vwastage of itheadhesive during the breaking operation. ..;Furthermore..a

thicker coating of adhesive must 'be' used I to compensate for losses resulting from the flocking of the adhesive from the paper-dur ing this breaking operation. v

By the process of our inventlon, we-are enabled to produce a non-curling'ystrip or' web by a rapid and continuous operation while securing an effective substantially continuous coating of adhesive upon. one surface thereof, which adhesive contains no oil will impair the bonding properties of, the adhesive, or interfere with the quick absorption of moisture thereby when it is'desired" those conditions which result in the distortion or curling of the paper rather than usingcorrective ingredients in the adhesive, or destroying the conditions developing such stresses after the aper has once been distorted or curled. is permits the adhesive to be. appliedina thin coating to the paper, ensures the entire quantity of adhesive'used being retained in this coating, and permits the economical production of the paper from the st-andpoints of time and labor whilesecuring a non-curling oduct. While the coating of adhesive is being applied toithe paper, and the vehicle orsolvent removed therefrom, the strip or web of pa r is sub jected -'to a continuing lon 'tudmal-stress which assists in preventing edis tortionor the vehicle or other moisture-repellent material which l I curling thereofduring the drying out process to which the adhesive coating is subjected. The time interval in the coatln of the paper is very short, and thefinis ed gummed product is sufliciently flexible, and

- the gum thereon issufiiciently dry, to permit although when applylng the gum t sheets the results will not be as good as when applying it to a strip or web, since the longitudinal stresses in the sheet can not be advantageously secured and the evaporation of the vehicle of the adhesive is more difficult and less rapid.

The invention consists primarily in the method of making gummed paper consisting in applying a solution containing adhesive material and a vehicle to the surface of paper, subjecting the same to a low temperature and then to a relatively higher temperature, whereby the vehicle will be removed from the surface of the solution inwardly thereof progressively to cause a progressive crystallization of the adhesive material and the readjustment of the adhesive material during its crystallization and avoiding those stresses result-ingin curling of the paper, and in an apparatus for carrying on said process; all as hereinafter set forth and described, and more particularly pointed out in the claims hereto appended.

In the accompanying drawing, we have illustrated an apparatus particularly adapted for use in the rapid gummingof a paper strip or web.

In the production of gummed paper by the method of our invention, we apply to one surface of the paper a solution containing an adhesive material and a vehicle, this solution being spread in a thin film throughout that portion of the paperwhich is to be gummed. The adhesive material usedin this solution ma vary widely as may the solvent constituting the vehicle, our invention not depending in any way upon the particular material .or solvent since with all adhesives the hardening thereof results from a drying out process, or the elimination, as by evaporation of the solvent or vehicle. This hardening action results in a crystallization of the adhesive material and the method of our invention resides in so controlling the speed of elimination, or evaporation, of the vehicle as to secure the complete hardening thereof without development of stresses resulting from the contraction of the adhesive as a mass, or its shrinkage as 9.

mass, to an extent to cause curling of the paper, due to the paper, particularly when dry, havin substantially no shrinkage or a lower shrmkage than the adhesive.

After the thin film of adhesive solution is applied to the paper, it is subjected to 'a low temperature as by passing 1t through a zone maintained at the desired temperature which may be ordinary factory temperatures or about to 90 F. Any particular temperature in this zone is not required so long as it is sufliciently low to cause a slow evaporation of the vehicle or. solvent and limit this action to adjacent the exposed surface of the film of adhesive solution.

Immediately following the subjection of the coated paper to this low temperature, it is subjected to a relatively higher temperature to cause the elimination or evaporation of the vehicle, or solvent, within the surface of the film of adhesive solution, the paper finally being subjected to a still higher temperature in order to ensure the completion of the elimination, or evaporation, of

the solvent throughout the entire mass of the adhesive and the complete drying of the exposed surface of the adhesive.

The best results can be secured by holding the paper substantial] flat or taut while it is being subjected to t ese different temperatures, and subjecting it to'a bendlng action before it is subjected to the higher temperature, or following hardening, or partial hardening, by crystallization, of the adhesive material adjacent the surface of the film and before the material between this surface and the paper has been thus hardto break or weaken the bond between adjacent crystals of the adhesive material and thus cause a readjustment of the solution while it is still in a'viscous or semi-plastic state, and a readjustment of this material of the solution in a manner to ,-.compensate for its shrinkage, or-contraction, as a mass and prevent the distortion or curling. of the paper. i

The portionof the adhesive solution which will be last to harden or crystallize will be that which is adhered, or'an'ehored, to the paper itself so that. the subsequent hardening of this portion of the adhesive by reason of the more or less separated por-- tions thereof entering the fibers of the paper, will have no effect of distorting the paper. 'While the method of our invention inthe higher temperature zone, and being suh jectcd to the final high temperature for between three to live seconds. These time intervals, however, are not inflexible, and will vary according to the adhesive material in the solution and the or solvent.

Satisfactory results can be secured with a temperature in the heated zone ranging from about 125 to 200.the highertemperature being utilized for the final stage,at which point the adhesives will have had substantially all of the vehicle or solvent removed,

so that the higher temperatures used will cause no reactions which will destroy the adhesive properties of the .gummed surface when moisture is applied thereto, when it .is desired to use the article made from the paper. The lower range or these higher temperatures represents the normal drop in the temperature of the air circulating in the heated zone, the first heated zon'ebemg characterized by thepresence of agraduated tcmjperatnre which becomes progressively higher with a lowering of the uautity of the vehicle or solvent 'in the 'ad iesi ve, or with the progressive elimination or evaporation of such moisture.

So far as we have been able' to determine, thepractice of the-method of'our invention is characterized by the following conditions.

As the paper with its coating film of adhesive solution is passing through the low temperaturezone, the vehicle. orsolvent of the portion of the adhesive adjacent the exposed surface thereof will rapidly be eliminated or evaporated, thus causing a hardening. or partial hardening of the solution superficially of this film. This. action will be accompanied by shrinkage of. the adhesive material of this portion of the solution, but

this shinkage will be in relation to the contiguous portions of the solution, and hence will merely cause a readjustment of these portions of the solution. or of the adhesive material without subjecting the paper to any of the stresses resulting from this contraction or shrinkage. This action will'go on progressh'ely through the thickness of the film so that by the time the treatment in the low temperature zone is completed, the

shrinkageor contraction of the material ofthe adhesive solution will have progressed to quantity ot the vehicle a point where any subsequent shrinkage will be so small as to have no eflect in imparting a curl to the paper.

At the conclusion of this stage the elimination, or evaporation, of the vehicle or solvent will not have occurred as to the whole mass of the adhesive solution, and the continuing escape of said vehicle or solvent will tend to keep the entire mass in a viscous condition. Hence a bending of the paper away from the coating film, accompanied by pressure resulting from stresses applied through the paper against the objectover whichthe paper is bent,will have the effect of causing the readjustment of different parts of the adhesive with relation to each other, in a manner to counteract any shrinkage or contraction which has occurred from the partial or complete hardening of some of the material. Consequently the subsequent rapid elimination, or evaporation, of the remain-.

ing vehicle or solvent will be accompanied by so little contraction or shinkage as to have no effect of curling the paper, particularly as during this stage, the portion of'the fl-adhesive solution which issubjected to contraction or shrinkage will be between that portion thereof superficially of the fihn and adjacent thereto and'ithe paper, and will meet with resistance ifrom the paper, and also from the previously hardened or partially hardened portion ofthe film. The

condition of theadhesive in passing from the low to the higher temperature stage 1s also such that the bending actionv accompanied by pressure will not cause crackageor flecking at the surface of the adhesive,

and may even be accompanied by a stretch' ing or attenuation of partially hardened portions of the film, or theseparation of adjacent particles in a manner to' prevent the development of those stresseswhich would curl the paper. i V

In passing through the zone of higher temperature, the vehicle or solvent between the superficial portion of the film of adhesive and the portion thereof which has been hardened or partially hardened, will be rapidly expelled from the adhesive, this portion of .the coating, however, having undoubtedly already been subjected-to a certain degree of contractionor shrinkage, and

having been readjusted with relation to the paper and to the hardenedor partially hard-' cued material, superficially of the film, and adjacent thereto. In fact, when passing through this stage, the drying out of the ad-,

hesive solution has progressed to a point where subsequent elimination of the remainl ing vehicle or solvent'will not result in such contraction or shrinkage-of the material of the coating asto apply any stresses to the paper.

The portion of the adhesive in direct contact with, and anchored to the surface fibers of the paper, with the elimination, either complete or partial, of the vehicle or solvent therefrom, will have the more or less segregated portions thereof contract or shrink in relation to the paper, and away from each other so'as not to be so bonded to adjoining crystals of the adhesive as to have any effect in developing stresses tending to distort or curl the paper.

'Ihroughont. the method is characterized by the hardening or partial hardening of a portiop of the adhesive material resulting from the elimination or evaporation of the vehicle or solventthercfor, accompanied by contraction or shrinkage of this portion of the adhesive, this contraction or shrinkage being with relation to portions of the adhesive which are still in a viscous or semiplastic form so as not to transmit any stressesigto the paper which would result in the curling action. lly thus avoiding the effects of such contraction or shrinkage, the thickness of the film of adhesive solution may be restricted to secure the desired thickness of the dried gum or other adhesive material upon the finished product, there being no losses due to the flecking of particles of the material as when breaking down a completely formed bridge of the crystals. Furthermore, there will be no cracking of I the dried adhesive.

The product is gummed paper having no appreciable tendency to curl, and having a thin continuous film of drled adhesive thereof the possibility of increasing the cheapness of the ingredients of the solution, and a reduction in the quantity of the adhesive used to coat the paper, but also by reason of the high speed at which paper, particularly in strip or web form, may becoated with the gum and the fact that the process may be carried on by means of an apparatus requlr ing little or no attention from the operator.

An apparatus suitable for use in the practice of said method or art is shown in the accompanying drawing. As shown, this apparatus embodies aframe 1 provided with bearings for a reel 2 for a roll of paper'to be coated. -Adja'cent said bearings is a fountain 3 adapted to receive a supply of the adhesive, this fountain having associated therewith a r0114 suitably surfaced to pick up adhesive from the fountain and apply it to paper fed with relation thereto. Cooperating with the fountain roll 4. is a feed roll'5, a tension roll 6 being positioned between this feed'roll and the supply reel of the paper supply roll.

Closely adjacent the adhesive solution applying mechanism, is a vertically extending housing or stack 7' open toward the bottom thereof so as to permit air to circulate freely through said housing or'stack.

The method is not only economical because The top of the stack is provided with a hood stantial alinement with the turning roller 9,

and a second roller 11 which, for convenience of expression, Wlll be termed a breaker roller, about which the paper strip or Web passes and changes its course from an upward to a downward run.

Mounted in the frame 1 is a rewind reel 12 co-operating with which are squeeze rollers 13 and 14 by which the paper strip or web is frictionally fed through the machine and rewound upon the reel 12. One of these rollers as 13 is driven from any source of power as the motor 15. Below the stack and in substantially vertical alinement with the roller 11 is a turning roller 16, and between this roller 16 and the squeeze roller 13 are suitable guiding and tensionin'g rollers 17, 18 and 19.

Mounted upon the frame 1 below the stack 7 is a roller 20 and adjacent the topof the stack is a second roller 21 about which an endless traveler-belt 22 of substantially the same width as the housing or stack, passes. The roller 21 is preferably of smaller di ameter than the roller 20. The belt 22 divides'the housing or stack 7 into two passages or conduits, which for all practical purposes are unconnected except adjacent the top of the housing or stack. One of these passages, indicated at 23, permits the circulation of'air at normal factory temperatures th'erethrough, so that it may properly be termed a cold ail-conduit. The other of these passages, indicated at 24, has heated air delivered thereto adjacent the bottom thereof from any desired source of heat, and

"hence may appropriately be termed a hot air conduit. In the upward run of the paper or web in the housing or stack 7, it passes through the cold, air conduit 23 andin its downward run, it passes through the hotair conduit 24 and toward the point'where the heated air is delivered to the stack.

In the form of the invention shown, the source for the heated air is an electrical resistance device 25 supported from the frame 1 of the machine adjacent the bottom of the housing or stack 7, and also adjacent the roller 20, so that air in passing between said housing and said source of heat will attain the temperature required in the practice of the method of our invention.

The feed roll 5 and the roller 20 are driven in any desired manner so as to secure a feeding of the paper strip or web from the supply roll, with substantially the same speed as that of the travel of the belt 22. The speed of the roller 13 is also such as to ensure the travel of the paper at substantially the same speed as that of said belt 22, while keeping the strip or web taut.

As shown. in the drawing, the roller -5 is driven from an electric motor 26, and is connected by a chain and pulley mechanism 27 with the roller 20 so as to secure the desired relative speeds of said rollers 5 and 20 to secure the above results. The paper strip or web is indicated at 28.

In an apparatus as herein described, the paper strip or web 28 is led from the roll upon the reel 2 under the tension roller 6, between the rollers 4 and 5, about the turning roller 9, over the guide roller 10, about the breaking roller 11, downwardly toward and about the rollers'lfi, 17, 18 and 19, between the squeeze rollers 13 and 14, and upon the rewind'reel 12. When the paper is thus threaded through the machine, it will be noted that the upward reach thereof is within the cold air conduit 23 of the housing orstack 7 and is positioned away from the upward reach of the belt 22, and that there is a progressively increasing capacity of this conduit toward the top thereof by reason of the inclination of the belt 22; and that the downward reach of the paper strip or web is within the hot air conduit 24. Toward the end of this downward reach, the gummed surface of the paper is resented towards the electrical resistance evice 25.

With this construction, as the paper stripv or web 28 passes between the rollers 4 and 5,. one surface thereof has a thin film of ad- .hesive solution from the fountain 3 applied thereto, the turning roller 9 having a spreading action upon thisfilm, although its main purpose is to change the direction of travel of the paper or web to an upward course through the cold air conduit 23. As the paperpasses through this cold air conduit, the gummed surface thereof is present ed away from the belt 22 where it will be subjected to the action of the air flowing upwardly through the'conduit 23. The ungummed surface of the paper will be held away from the belt 22 by the upper guide. roller 10. This upward reach of the roller is approximately 30 feet long, although this lengthis stated as merely one at which satis-' factory results have been attained, and not as being essential.

After passing the guide roller -10, the strip or web 28 passes about the roller l1? where .it receives a fairly sharp bend, and is subjected-to pressure resulting from the drag upon the strip-by the squeeze rollers 13 and 14, and passes downwardly through the hot ain conduit 24.- It will be observed that during\the part of this travel adjacent the to of thehousing or stack 7, the hot air wi l have lost some of its heat through radiation, and that hence there will be agradually increasing temperature from this point to -a point adjacent the heater 25 where the temperature will be at its highest. Hence during the downward travel of the paper strip or web 28 through the hot air conduit, it will be subjected to a progressively higher temperature, and will, while passing the heater 25, be subjected to a sub stantially uniform high temperature.

While the strip or web 28 is passing upwardly through the conduit 23, the cold air will act superficially of the film of adhesive solution upon the paper strip or web, the rapid circulation of cold air ensuring a condtinuous supply of fresh air and a change of this alr with sufficient rapidity to carry off the vehicle or solvent for the adhesivc'material as it evaporates from the solution. This action will be gradual, and will have the effect of limiting the initial hardening action to adjacent" the surface of the film of the solution.

In passing about the breaking roller 11,

hardened portions thereof, to compensate for any shrinkage or contraction of the portion thereof which has been hardened or partially hardened.

During the downward run of the paper strip or web 28 through the hot air conduit- 24, the coated surface of the paper will be presented away from the belt 22 and the igher temperature of the air circulating through this conduit-will cause a rapid elimination, or evaporation, of the vehicle or solvent remaining in the film of thesolutiom Throughout at leasta portion of the travel of the paper strip or web through this conduit 24, the surface of the adhesive film will be tacky, but the passage thereof adjacent the heater 25 will have the eifect of a final rapid drying action upon this coating, so that after theistrip or web 28 leaves its proximity to the heater, the adhesive will be sufliciently dry and hard to permit it to 'pass the various guide and tensioning rollers 16, 17, 18 and 19 and thexsqueeze rollers 13 and 14, and be rewound upon the reel 12 without any likelihood of the gummed surface of the paper strip or web adhering to these rollers or to the strip previously wound upon said reel.

'We have found an a-pparatusasherein described, to give highly satisfactory re-; salts, and to produce a gummed paper which has no tendency to curl, so that gummed paper may be Withdrawn from the roll upon said reel and passed through a printing machine, and have a clean sharp impression applied to every portion thereof.

, claim as new and desire to have protected by Letters Patent, is

1. The herein described method of making gummed paper consisting in applying a solution containing adhesive material and a vehicle to one face only of paper, subjecting the same toa low temperature and then to a relatively higher temperature, whereby the vehicle will be removed from the surface of the solution inwardly thereof progressively to cause a progressive crystallization of the adhesive material and there-- adjustment of the adhesive material during its crystallization and avoiding those stresses resulting in curling of the paper.

2. The herein described method of making gummed paper consisting in applyin a solution containing adhesive material an a vehicle to one face only of paper, subjecting the same to a low temperature, then to a relatively higher temperature, whereby the vehicle will be removed from the surface of the solution inwardly thereof progressively to cause a progressive crystallization of the adhesive material and the readjustment of the adhesive material during its crystallization and avoiding those stresses resulting in curling of the paper, and thereafter subjecting the same for a short interval to a relatively higher temperature to ensure a thorough drying out of the adhesive at the surface thereof.

3. The herein described method of making gummed paper consisting in applying a solution containing adhesive material and a vehicle to one face only of the paper, circulating air' at a low temperature adjacent said surface, and thereafter circulatingair at a relatively higher temperature adjacent said surface, whereby the vehicle will be removed. from the surface of the solution inwardly thereof progressively'to cause a progressivecrystallization of the adhesive material. and the readjustment of the adhesive material during its crystallization and avoiding those istresses resulting in curling of the paper. The herein descrilgedmethod of making gummed paper consisting in applying a solution containing adhesive material and a vehicle to one face only of the paper, circulating air at a low temperature adjacent said surface, thereafter circulating air at a relatively higher temperature adjacent said surface, whereby the vehicle will be removed from the surface of the solution inwardly thereof progressively to cause a progressive crystallization of the adhesive material and the adjustment of the adhesive material during its crystallization and avoiding those stresses resulting in curling of the paper, and thereafter subjecting the same for a short interval to a relatively higher temperature to ensure a thorough drying out of the adhesive at the surface thereof.

5. The herein described method of making gummed paper consisting in applying and spreading a solution containing adhesive material and a vehicle to one face only of a strip or web of paper, passing said strip or'web upwardly wlnle subjecting it to circulating air at low ten'lperature, and thereafter passing said web downwardly while subjecting it to an upward circulating airat a relatively higher temperature, whereby the vehicle will be removed from the surface of the solution inwardly thereof progressively to cause a progressive crystallization of the adhesive material and ,the readjustment of the adhesive material during its crystallization and avoiding those stresses resulting in curling of the paper.

6. The herein described method of making gummed paper consisting in applying and spreading a solution containing adhesive material and a vehicle to one face only of a strip or web of paper, passing said strip or web upwardlywhile subjecting it to circulating air at low temperature, thereafter passing said web downwardly while subjecting it to upwardly circulating air at a relatively higher temperature, whereby the vehicle will be removed from the surgressively to cause a progressive crystallization'of the adhesive material and the readjustment of the adhesive material'during its crystallization and avoiding those stresses resultin in curling of the paper, and thereafter su jecting the same for a short interval to a relatively higher temperature to ensure a thorough drying out of the adhesive at the surface thereof. 7. The herein described method of making gummed paper consisting in applying a solution containing adhesive material and a vehicle to one face only oflpaper, subjecting the, same to a. low temperature, giving a sharp bend to the paper in the direction away from the surface having the adhesive thereon and simultaneously applying stresses to the paper on opposite. sides of the point where it is bent, and thereafter to a relaof a strip or web of paper, passing said strip or web upwardly while subjecting it to circulating air at low temperature, giving a sharp bend to the paper in the direction away from the surface having the adhesive thereon and simultaneously applying stresses to the paper on opposite sides of the point where it is bent, and thereafter passing said web downwardly while subjecting it to upwardly circulating air at a relatively higher temperature, whereby the vehicle will be removed from the surface of the solution inwardly thereof progressively to cause a progressive crystallization of the adhesive ma terial and the readjustment of the adhesive material during its crystallization and avoid ing those stresses resulting in curling of the paper.

, 9. The herein described method of making guinnied paper consisting in applying a so lution containing adhesive material and a vehicle to one face only of paper, subjecting the same to a low temperature, giving a sharp bend to the paper in the direction away from the surface having the adhesive thereon and simultaneously applying stresses to the paper on opposite sides of'the point where it is bent, thereafter subjecting it to a relatively higher temperature, whereby the vehicle will be removed from the surface of the solution inwardly thereof progressively to causea progressive crystallization of the adhesive material and the read-- justment of the adhesive material during its crystallization and avoiding those stresses .resulting in curling of th paper, and thereafter subjectin the sam for a short interval to a relatively higher temperature to ensure a thorough drying out of the adhesive at the surface thereof.

10. The herein described method of making gummed paper consisting in applying .and spreading a solution containing adhesive material and avehicle to one face only of a strip or web of paper, passing said strip of web upwardly while subjecting it to circulatin' air at low temperature, giving a sharp fiend to the paper in the directioiiaway from the surface having the adhesive thereon and simultaneously applying stresses to the paper onv opposite sides of the point where it is bent, thereafter passing said Web'downwardly while subjecting it to upwardly circulating air at a relatively hlglier temperature, whereby the vehicle will be removed from the surface of the solution.

inwardly thereof progressively to cause a sive material during its crystallization and avoiding those stresses resulting in curling of the paper, and thereafter subjecting the same for a short interval to a relatively higher temperature to ensure a thorough drying out of the adhesive at the surface thereof.

1.1. The herein described method of making guinined paper consisting in applying a solution containing adhesive material and a vehicle to one face only of paper, subjecting-the same to a low temperature and then to a relatively higher, and a gradually iiicreasing, temperature, whereby the vehicle will be removed from the surface of the soll1- tioii inwardly thereof progressively to cause a progressive crystallization of the adhesive material and the readjustment of the adhesive material during its crystallization and avoiding those stresses resulting in curling lization of the adhesive material and the readjustment of the adhesive material during its crystallization and avoiding those stresses resulting in curling of the paper, and there after subjecting the same for a short interval to a relatively higher temperature to ensure a thorough drying out of the adhesive at the surface thereof.

13. The herein described method of making gummed paper. consisting in applying and spreading a solution containing adhesive material and a vehicle to one face only of a strip or web of paper, passing-said strip or web upwardly while subjecting it to circulating air at low tein 'ie'rature. thereafter passing said web downwardly while sub ecting it to upwardly circulating air at a relatively higher, and it gradually increasing, temperature, whereby the vehicle will be removed from the surface of the solution inwardly thereof progressively to cause a progressive crystallization of the adhesive material and the readjustment of the adhesive material during its crystallization and avoiding those stresses 'esultin in curling of the paper, and thereafter subjecting the same for a short interval to a relatively higher temperature to ensure a thorough drying out away from the surface having the adhesive thereon and simultaneously applying stresses to the paper on opposite sides of the point where it is bent, thereafter subjecting it to a relatively higher, and a gradually increas ing, temperature, whereby the vehicle will be removed from the surface of the solution inwardly thereof progressively to cause a progressive crystallization of the adhesive .material and the readjustment of the adhesive material during its crystallization and avoiding those stresses resulting in curling of the paper, and thereafter subjecting the same for a short interval to a relatively higher temperature to ensure a thorough drying out of the adhesive at the surface whereby thereof.

15. An apparatus for making gummed paper embodying therein means supporting a roll of'paper to be coated, a fountain for a solution of adhesive material, a fountain roll, a feeding roll co-operating therewith, and adapted to apply the adhesiveto one surface only of the paper to be coated, a stack open at the bottom and at the top thereof, means dividing said stack into two substantially vertical passages, means for guiding the coated paper strip or web in an upward run through one of said passages, and in a downward run through the other of said, passages, means whereby the temperature of the air passing through the last named of said passages is heated, a rewind reel, guiding means intermediate said last named means and said rewind reel, and

'means drawing the paper from said supp] reel and winding it upon said rewind ree, said paper is subjected to continu ous longitudinal stresses.

c 16. An apparatus for making gummed paper embodying therein means supporting a roll of paper ,to be coated, a fountain for a solution of adhesive material, a fountain roll, a feeding roll co-operating therewith and adapted to apply the adhesive to one surface only'pf the paper to be coated, a

stack open at the bottom and at the top thereof, means dividing said stack into'two substantially Vertical passages, means for guiding the coated paper strip or web in 'an upward run through one of said passages,

abreaker roller adjacent the top of .the means dividing said stack, abou t ,whichthe paper strip or web passes int'o downward run through the other of said passages, means whereby the temperature of the air passing through the last named of said passages isheated, a rewind reel, guiding means "intermediate said last named means and said roll, a feedingroll co-operating therewith and adapted to apply the adhesive to one surface only of the paper to be coated, a stack open at the bottom and at the top thereof, rollers adjacent the top and the bottom of saidstack, an endless belt passing about said rollers whereb said stack is divided into two substant1ally Vertical passages, means for guiding the coated paper strip or web in an upward run through one ofsaid passages, and in a downward run through the other. of said passages, means whereby the-temperature of the air passing through the last named of said passages is heated, a rewind reel, guiding means intermediate said last named means and said rewind reel, and means drawing the paper from said supply reel and winding it upon said rewind reel, whereby said paper is subjected to continuous longitudinal stresses.

18. An apparatus for making gummed paper embodying therein means supporting a roll of paper to be coated, a fountain for a solution of adhesive material, a fountain roll, a feeding roll co-operating therewith, a

stack open at the bottom and at the top,

sages, means for guiding the coated paper strip or web in an upward run through one of said passages, a breaker roller adjacent the upper of said rollers about which said belt passes, about which the paper strip or web passes into a downward run through the other of said passages, means whereby the temperature of the, air passing through the last named of said passages is heated, a rewind reel, guiding means intermediate said last named means and said'rewind reel, and means drawing the paper from said supply reel and winding it upon said rewind reel, whereby said paper is subjected to continuous longitudinal stresses.

19. An apparatus fornnaking gummed paper embodying therein means supporting a roll of paper to be coated, a fountain for a solution of adhesive m aterial',;-; afountain roll, a feeding-roll co operat-ingfgthere yith, a

stack open at the bottom and at the top thereof,rollers adjacent the top and the bottom of said stack an endless belt passing about said roller: whereby said stack is sages, means for guiding the coated paper strip or web in an ugward run through one of said passages, a reaker roller adjacent the upper of said rollers about which said belt passes, about which the aper strip or web passes into a downward run throu h the other of said passages, means where f the temperature of the air passing throng 1 the last named of said passages is heated, a rewind reel, guiding means intermediate said last named means and said rewind reel, squeeze rollers engaging the web adjacent said rewind ree1 and acting u on the web wound upon sald reel, where y said through said stack and subjected tdcohtinuons longitudinal stresses, and means wherebysaid feeding roll, and said fountain roll, and said squeeze rollers are respectively rotated at the same peripheral speed and said belt isdriven at substantially the same speed. as that of the paper strip or web. 4

paper is drawn Inwitness whereof we have hereunto ,af-

fixed our signatures ary, 1926. v

WILLIAM HENRY SMITH. I ALBERT a. STEWART \WEBSTER.

this 19th day of J anu-

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