US1624091A - Coated paper board - Google Patents

Description

Patented Apr. 12, 1927. v UNITED STATES I I I 1,624,091 PATENT OFFICE,

CHARLES c. 'connEnr AND GEORGE E. PRESTON, or n-mmnmr, mums, assronons T AMERICAN coa'rma mas, or ELKHAB'I, momma, A conroaa'rron or Innmna COATED PAPER Beam).

Nomawing. Original application filed July 2, 1923, Serial No. 848,888, new Patent No. 1,514,489, and in Canada October 14, 1924. Divided and this application filed October 28, 1924. Serial 110(7453527.

Coated paper board of highly desirable quality, having advantageous stifiness and snappy character, has been produced by the present inventors by a process disclosed in their Patent No. 1,514,439, dated November 4, 1924, to which reference is hereby made as a part of this specification.

' The process referred to involves formation of the board from wet stock in a con- 1 tinuous web while successively treating the accumulations alternating with lineally running portions of the board; and the coating operation is cbnducted while drawlng the board with appropriate tensioning from a preceding accumulation; while the finishing operation is conducted while drawing the dry coated board from a succeeding accumulation, likewise under appropriate tensioning conditions.

These accumulations are flexible in the sense that the quantity of board stored therein is variable to permlt continuity of production of the board from wet stock and continuity of delivery of the finished coated product while permitting temporary interruptions in the coating operation as may be necessary for changing materials, cleaning brushes or other IIGCGSSltlGS.

An illustrative ractice of the method aforesaid, as descri ed in said patent, .is set 4 forth in thefollowing description. s

- In said patent, there is shown for example a paper board-makin machine of the type comprising a series 0 cylinder molds which successivel a 1 is are of pulp to an endless felt t2; f r hi all wet laminated board web. Ordinarily theboard is composed of difierent classes of stock, for instance cheap newspaper stock for the intermediate layers and white manila stock for the surfaces of the board or at least the surface which is to be calenderedand coated.

The wet board web forming continuously on the felt is carried between appropriate presses .or squeeze rolls, which squeeze out or more sets of calendering rolls from which 7 it is continuously delivered in dry and calendered condition. The calendered surface of the board for application of the liquid coating is usually supplied by the liner- 0f white or'superior stock from one cylinder mold, this being the top surface of the board.

The calendered board is delivered into a v flexible accumulation which in the patent referred to is provided by apparatus for hang- 1ng up the board in festoons or; folds. The capacity of this apparatus is such as to store a large quantity of the hanging festoons of board, whereby v the freshly produced raw board, before undergoing the coating operation, is subjected to a seasoning process by prolonged exposure to the atmosphere while in hung-up condition. Provision is made for varying the number of hanging festoons in the apparatus so as to permit continued accumulation of the continuously supplied board in hung up condition in the delivery end of the apparatus, during tem orary interruptions in the operation of t e coating machine; and the excess accumulation thus stored may be drawn off after resuming the coating operation by temporarily speeding the coating appliance, thus restorlng normal conditions.

From the accumulation in the hang-up apparatus, the board is drawn through a coatmg machine in such manner as to take up the slack gradually and to tension the board for coating without subjecting it to sharp or sudden stresses in its transit from the slack condition to tensioned state. This may be accompl ished by drawingthe boardin contact wit may be drawn over a frictional surface in advance of drawing it over guide rollers to the coatin machine. The board is also guided to t e coating machine in such manner as to expose on the cylinder of said machine the top calendered surface of the board, which in passing through the machine receives the liquid coating, and to deliver the board coated side uppermost from said machine. The coating applied to the board is usually a liquid. coating such. for instance as a solution of clay and casein with or without coloring pigments, which may be applied by a' rotating brush supplied with the coating liquid from a fountain roll, and the liquid is brushed thoroughly into the board by reciprocating brushes asthe board passes through the coating machine.

' The coated board delivered from the coating machine is accumulated in hanging lestoons or folds and subjected to drying action, which as described in said patent is conducted in a drying room through which the hanging festoons of board are slowly conveyed; and provision is made through the heating arrangements of the drying room and by occasional shifting of the points of suspenjon of the festoons of board for subjecting the web to substantially uniform drying treatment; Beyond or at the delivery end of the; drying room a number of the hanging folds of dry coated board are collected in a flexible supply providing a reserve from which the boardmay be withdrawn for the ensuing finishing operation 1 during temporary interruptions ot the coat ing operation, which interruptions are .accompanied by stoppage of the drying room conveying system; and the reserve supply referred to may be replenished upon resumption of the coating operation by the temporary speeding up-of the coating machine for withdrawal or the excess accumulated in the preceding accumulation from which the board is drawn for coating.

From the accumulated supply at or be yond the delivery end of the drying room,

the dry coated board is drawn through a-supercalendering machine for the finishing operation. Preceding the supercalendering machine are appropriate means for smoothing and progressively tensioning the board until it is drawn with requisite tenseness for the supercalendering operation. For these purposes the board may be drawn over a curved frictional surface or surfaces and around frictionally retarded rolls. @oop-- crating with these smoothing and tension ing agencies are means for aligning the board web and for overcoming any tendency 'to run -at a bias or the lilre, which, in conjunction with the drawing of the board tense, minimizes tendencies to creasing or -wriiokling of the board as it is drawn into the rolls of the supercalendering machine. The supercalendering machine irons outthe hoard and imparts a sheen or gloss to its coated surface, and: if desired the finish,

ing of the coated surface of the board may efiected in part by agencies supplement oil treatment.

. neaaoer ing the finishing action of the supercalen-- doring rolls.

From the supercalendering machine the board may be passed, through a synchronously operating cutting machine which subdivides the board and delivers the product in cut flat sheets ready to be immediately packaged for shipment. In some instance, to comply with particular trade requ1re ments, it may be desired to package the board in rolls, in which case the finished product maybe delivered to an appropriate reeling machine. v

The method above described has important edects upon the quality of the product,

particularly as to stifi'ness and snappy character. From the period of formation of the raw board trom the wet stock until the'delivery of'the finished product, the board is maintained in an open disiended condition,

there being no intermediate reelings and unreelings of the board or lapping it upon itself; and the successive operations which the board undergoes are such as to stress every portion of the board uniformly and to produce a substantially uniform setting of the fibrous structure having a general tendency to straightness, no portion of the board being flexed under tension at any ditterent radius than other portions. Moreover thereisno repeated or prolonged bending of the board back and forth upon itself. between successive stages of manufacture such as to weaken the natural rigidity of the fibrous structure of the board. During the'greater portion of the entire time between the ca'lendering of the raw board and thedelivery of the finished product, the continuous board web is stored in relatively stagnant accumulations between successive machines, and the sheet is tensioned onl in running it through successive machlnes. Furthermore the transition of the web from slack to tensioned condition is gradual or consistent with the constituency and thiclrl ness or" the board material.

Prior to the present invention, the ordinary commercial manulacture of coated board involved the roduction oil the raw board in a board-rushing lent; reeling the output trom the board-m g machine and ill then unreeling and passing it through a trimming machine and rereeling it into even edged rolls; transporting these rolls to a coating machine; mounting the rolls one at a time in a reel associated with the coating machine; drawing the board through the coating machine and then through a drying room; reeling the coated boarddelivered from the drying room and unreeling and rereeling it to form an even edged roll; removing the roll of coated board to a calendering or finishing machine, and again mounting it in a reel, drawing it through the finishing machine and reeling, unreeling and rereeling the finished board into an even edged roll, either for merchantable purposes or for removal to still another machine through which the board was drawn from the roll and cut into sheets.

Thus the board material, between the stages of production of the raw-board and the delivery of the finished coated product,

was repeatedly reeled, unreeled and rereeled,

thereby subjecting the fabric to strain and flexure under tension, with consequent tendency to diminish the stiffness and snappy characteristic of the board. Furthermore the storage of the board in rolled-up condition between successive stages of manufacture caused it to set in rolled-up form, with consequent tendency to resume its curvature during ensuing stages of treatment and in the finished state, thereby diminishing the capacity of the board to stand up stifi in the carton. As' the board in the rolls set with its successive layers at different radii, there nary commercial method above referred to.

For instance, coated board of .0014 inch thickness, made by the present method, may be used and is satisfactory for manufacture of cartons in place of board of .0016 inch thickness made by said ordinary method.

We claim: Paper board endered liner having a finished coated surface, the fabric structure of the board being of a substantially uniform set and retaining substantially the maximum rigidity inherent in the material of which the board is composed, and the board possessing a pronounced stiffness and snappy characteristic, such fabric structure being characterized by its manufacture from the wet stock to the finishedcoated product without rolling. up or lapping the board upon itself or subjecting it to severe flexing under; tension.

In testimony whereof, we have signed our names to this specification.

CHARLES C. COLBERT. GEORGE E. PRESTON.

composed of consolidated layers of paper material including an outer cal-