US2091572A - Paper manufacture - Google Patents

Description

Aug. 3l, 1937. .1. H. SWAN. 3D

`PAPER MANUFACTURE AFiled Feb. 15, 1954 :inventor Patented' Aug. 31, 1937 UNr'rEo STATES OFFICE PAPER MACTURE Joseph H. Swan, IH, Middletown, Ohio, assignor to The Gardner-Richardson Company, Middletown, Ohio, a corporation of Ghio This invention relates to paper manufacture, and more particularly to an apparatus for applying a coating to a sheet of paper.

It is a principal object to provide a compactl 5 and simple apparatus for applying coating material to a, traveling web of paper such as paper, paper board, and the like.

It is a further object to provide apparatus for applying multiple coatings to a traveling web of 10 paper, and for separately drying each coating, which apparatus is conveniently located and easily accessible for the attention of the operator.

It is a further object to provide apparatus for readily handling and renewing the rolls of paper l5 material.

Other objects and advantages will be apparent from the description and the appended claims.

In the drawing:-

Fig. 1 is a schematic view showing the general 2 arrangement of the coating applying apparatus and the drying apparatus associated therewith;

Fig. 2 is a detail view showing the apparatus for handling the rolls of paper; y

Fig. 3 is a View along the lines 3--3 of Fig. 2;

25 and Fig. 4 is a broken horizontal sectional view along the line 6 4 of Fig. 1.

This invention provides a form of apparatus applicable generally for use in applying coating 3@ materials to a sheet of paper or the like, and is more particularly constructed for use in conjunction with the production of a greaseproof paper product and process, such for instance as described in my co-pending application, Serial 35 No. 389,425, filed August 30, 1929, now Patent No. 1,957,369, issued May 1, 1934. As disclosed in said application, a composite greaseproong coating is applied to a traveling web of paper, the coating being dried following the application 4@ of each component layer of the composite coating. In accordance with the present invention, means are provided for applying coating materials, and for thereafter drying the applied coatings, the entire apparatus being convenient- 5. ly arranged so that it can be easily attended with a minimum of diilculty. v

Referring to the drawing which discloses a preferred. embodiment of the invention, there is shown at l a roll of paper adapted to be ro- 5@ tatably supported and unwound to provide a traveling web of paper li which is passed through the coating machine. This roll is preferably wound upon a core which is mounted upon the shaft l2, extending axially beyond the roll face se to provide for rotatably supporting the roll. At

opposite sides of the roll, the shaft I2 is mounted in open ended bearing members I3 which are formed as a part of a traveling carriage I4. Each carriage I4 comprises a pair of rollers I5 having double flanges I6 adapted to ride upon a longitudinal track member Il. Each track member is pivotally supported at one end as at I8, upon a suitable pedestal I9. Means are provided for lowering the opposite end of each track, such as the pair of jacks, indicated generally at 20. 10 These jacks maybe of any desired construction such for instance as a hydraulic jack, and means are conveniently provided under the control of the operator for simultaneously raising and lowering both such jacks, to thereby raise and lower the ends of the tracks Il.

The purpose of dropping the tracks to the position shown in Fig. 2 is to enable a fresh roll of paper to be conveniently placed upon the tracks. The fresh roll may be brought up to the supports on a truck or the like, and the truck wheeled between thetwo track members, the roll being directly positioned. in the bearing members I 3'. Thereafter the jacks areraised to bring the tracks into the level position, and the fresh roll of `paper can be unwound and pasted to the expiring roll to be carried through the machine in this manner. Thereafter the expired roll is removed from its journals I'3, and the corresponding carriages Ili are manually lifted from the track. The carriages I supporting the fresh roll of paper are then moved longitudinally along the track upon the rollers I5' to the operative position as shown in Fig. 1, and the other pair of carriages are then positioned for reception of a fresh roll. Suitable pins 2l cooperating with holes in the track, provide for holding the carriages in desired position.

The traveling web of paper II as it leaves the roll I0 passes under a guide roll 25, and into 40 Contact with a rst coating applying means indicated generally at 26. This comprises a lower roll 2l dippinginto a trough 28 which may contain the coating composition to be applied at this point, suitable supply means being provided to maintain a constant level of the composition in this trough. Roll 2l picks up on its surface a film of the coating and carries it into contact with the upper roll 28a, which roll transfers a layer of controlled thickness to the web.

The coating composition applied at this point may, for example, comprise essentially rubber latex and casein. The addition of an oil insoluble adhesive, such as casein, to the rubber latex imparts superior characteristics of adhesiveness and greaseproofness. Rubber latex has qualities of elasticity and spreading ability and enables a relatively thin coating to be used with satisfactory covering power; italso functions very 5 satisfactorily to lay any fuzz which may be protruding from the surface of the paper and covers up irregularities of the surface. It is also'a good moistureprooflng and waterproong agent. Other oil insoluble adhesives may be used, and

alkaline material may be added to increase the effective life of the coating. Also a preservative such as formaldehyde may be added. Furthermore the addition of a polysulfide is found to improve the covering power and to prevent deterioration and the formation of pin holes in the coating.

The web of paper with the applied coating thereon then passes around a guide roll 29 and is contacted by one or more, revolving rolls 30.

The roll or rolls are positively driven against the direction of travel of the paper, and serve to reduce the lines and streaks in the coated surface of the sheet usually produced by the coating press. Each roll may be positioned slightly obliquely with respect to the paper web, as it is found that this oblique positioning tends to improve its functioning.

The web with its partially smooth coating layer next passes-into contact with one or more brushes 3|. These brushes are preferably reciprocated transversely of the sheet, and serve to further remove whatever streaks or lines still remain after the action of the smoothing roll 30. In some cases it is found ,that the brushes themselves will leave certain brush marks upon the coated surface of the sheet, and in order to effectively remove such brush marks, a second set l of smoothing and spreading rolls 32 may be provided, following the brushes 3|. The rolls 32 likewise are preferably driven against the direction of travel of the sheet, and may also be po sitioned obliquely with respect thereto. Following this combined brushing and smoothing action, it is found that -a very superior uniform coating, evenly distributed, and quite free from minute defects or .pin holes, is present upon the sheet.

The sheet then passes over a roll 35 and into a drying chamber 36. This chamber is preferably an elongated substantially completely enclosed chamber within which the coated surface of the web is subjected to drying fluid. blasts, and in which the web is also subjected to a seasoning.

treatment. Thev sheet enters one end of the chamber through a relatively narrow slot 3l, and is supported throughout its travel on a series of supporting rolls 38. The drying iiuid blasts are directed downwardly upon the upper coated surface of the web from a plurality of supply ducts 39, adapted to discharge the drying medium,

usually heated air, directly upon the coated surface of the web. 'Ihus it will be seen that following the smoothingA and spreading action, no vfurther contact is had with the coated surface of the web during the drying operation.

By the time the web has reached the remote end of the drying chamber, it is sufficiently dried so that contact with a roll will not damage the surface. At this point the web passes around a turn-over roll 40, whichmay be slightly crowned to cause centering of the web, and returns through the elongated chamber, supported upon a second series of rolls 4i. While no iiuid blast is directed upon the web during this pass through the chamber, yet it is in the heated and drying atmosphere of the chamber, and therefore is subjected to a desired seasoning treatment.

'I'he web leaves 'the drying chamber at the same end at which it entered, and, passing over guide rolls 44 and 45, it is brought into contact. with a second coating applying means 46. This means comprises a lower roll 41 dipping within a trough 48 to which is supplied the coating material desired to be applied at this point. Roll 41 runs in contact with the application roll 48, transferring to said roll a film of color to be brought into contact with and applied .in a layer l the greaseproofng character of the coating.

The composite coating as thus formed therefore comprises a lower layer including the rubberl material, and having high flexibility, and an upper layer including the casein, and having high greaseproofness, the two layers being interbonded, the sheet and composite coating thereon serving to maintain the impervious character of the composite coating against disruptive effects in use due to bending and the like.

The web is then preferably brought into contact with a rotary brush 50, revolving against the direction-of the travel of the paper, which brush serves to remove the lines or streaks produced at the coating press. After passing around a guide roll 5|, the web may then be brought into contact with additional -brushes 52, preferably of the reciprocating type, which serve to remove any marks left by the rotary brush 50. Smoothing and spreading rolls 4may be used at this point if desired, but with the coating of the character described it is usually found that no further smoothing and spreading is required.

'Ihe web continues over a guide roll 53, and into the dryingchamber 36 for another pass, supported on a third series of supporting rolls 54.

pls

Drying nuid masts from the ducts 55 are 11-,`

rected upon the surface of the web, and it is substantially dried by the time it reaches the remote end of the chamber. A second turn-overv roll 56, similar to roll 40, [reverses the direction of travel of the web, and it is brought back over the series of rolls 5l through the chamber where it is submitted to further seasoning treatment. It emerges from the chamber at the same end at which it entered, and passes through the nipof rolls 58, 59, which serve to pull the web through the coating and drying apparatus. In any case where, due to the strength characteristics of the web or to increased frictional effects, further driving is desirable, another of the supporting or guide rolls previously described may be -positively driven to feed the web forward.

The web then passes around guide rolls Ell and through further coating presses 6| and 62. Any desired material may be supplied by these rolls, such for example as a solution of a metallic salt for the purpose of fixing and precipitating the A,casein in thev top coating described above, which metallic salt may be supplied by the rolls 6l. In

some cases it is also desirable to apply an overlying coating adapted to eliminate taste and odor of the casein, a suitable material for example being sodium silicate, and in such case the rolls 62 may be utilized to apply a thin coating of sodium silicate.

When the web is started through the coating applying machine, it may be threaded by hand through the first coating press, and then brought over guide roll 35. At this point a carrying and threading means is provided for threading the web through the drier chamber. This mechanism preferably comprises an endless traveling rope or carrier member 65 which is` looped around roll 35, this roll being sitively driven and being therefore adapted to drive the carrier member 65. 'I'his carrier travels over the supporting rolls 38, lying directly thereon, and laterally to the side of the traveling web. A convenient attaching means 56 may be clipped to the carrier and to the end of the web during a threading operation which is preferably tornas indicated generally in Fig. 4. The carrier threads the web over the rst pass of supporting rolls, and around the turn-over roll and back over the second pass of supporting rolls 4 I. 'I'he attendant then receives the end of the web and manually threads it through the second coating applying press. Thereafter it is brought over guide roll 53 and again attached to the carrier member, to be thereby threaded through the drying chamber and over supporting rolls 54, turn-over roll 56, and supporting rolls 51 successively. The web is then brought out of the machine by the carrier and is manually threaded through the remainder of the coating presses. This endless carrier therefore constitutes a very simple and effective means for threading the sheets through the drying chamber.

It will be appreciated that by reason of the present invention the entire operating structure requiring any attention on the part of the operator is positioned close together and in such position that the substitution ofy a fresh roll, and the operation of all the coating presses can be easily watched by a single attendant. Furthermore, because of thisconstruction, the web as it passes through the elongated drying chamber is subjected not only to drying but to a seasoning treatment which serves to condition and further improve the applied coating layer.

While the form of apparatus herein described constitutes a preferred embodiment of the invention,` it is to be understood that the invention is not limited to this precise form of apparatus, and that changes may be made therein without departing from the scope of the invention which is dened in the appended claim.

yWhatis claimed is:

In a coating apparatus for applying a coating of predetermined characteristics to a 'traveling sheet of paper, the combination of application means, and smoothing means comprising a roll engaging the coated surface of the paper and rotating in a. direction opposite to the travel ofthe paper, a brush following the roll for brushing the coated sheet, and a second roll for thereafter engaging the sheet and rotating in al direction op-

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