US2319800A - Means and method for improving the quality of paper - Google Patents

Description

y 1943- J" R. DENTON 2,319,800

MEANS AND METHOD FOR IMPROVING THE QUALITY OF PAPER.

Filed-April. 21., 1941 ISnventor JESS R BENTON Z l m Gttorneg Patented May 25, 1943 UNITED 'STATES PATENT OFFICE MEANS AND METHOD FOR ILIPBOVING THE QUALITY OF PAPER Jess R. Denton, Brevard, N. 0., assignmto Ecmsta Paper Corporation, a corporation Delaware Application April 21, 1941, Serial- No. 339,586

9 Claims.

My invention relates to means and methods for improving the properties oi paper particularly high quality paper, such as cigarette paper. The

- invention is described hereafter with special refcations as to appearance rating, opacity, porosity, stretch, tensil strength, and uniformity of distribution of the several components of the paper, such as fibre and filler, while still maintaming sufiiclently high production to make the process commercially feasible. The present day reouirements for the appearance of cigarette paper are often difficult to obtain and many attempts are being made continuously to improve the processes under which the paper is manuioctured. These include mechanical devices that afi'ect the nature and formation of the continuone web of paper on the paper machine such as a Fourdrinier machine, as well as various modl ficaticns in the digesting, bleaching and refining procedures that precede the paper machine. None of these attempts, however, has accomplished the optimum results oi my invention.

To provide a distinguishing watermark or other decorative cheat on high quality diaphanous paper it has been common practice to impress the wet paper web with a roll called a dandy roll. In the manufacture of cigarette paper a dandy roll, having closedy spaced parallel wires supported by spaced rings that form the outer periphery of the roll, has been used to provide the fine lines that characterize a number of cigarette papers today. This type of dandy roll is commonly referred to as a "laid dandy roll and the fine parallel lines are commonly called laid lines. These lines tend to compensate for irregularities in the appearance oi the paper but they do not materially improve the several above mentioned physical properties of the paper and do not fulfill the desideratimi of manufacturers of high quality paper.

In accordance with my invention egregious improvement in the appearance and in the various physical properties, such as above enumerated, has been made possible by utilizing in additlon to the usual dandy roll or, the like, a second roll having surface characteristics adapted to pmcess the paper as described hereafter.

This second roll is not used in. the common sense oi a dandy roll but rather as a. smoothing or processing roll which apparently rearranges, straightens, and smooths the fibers and other constitutents in the paper web and provides en tirely unexpected and exceedingly desirable characteristics in the finished paper. Also viit has made possible substantial increase in the paper production rate without sacrificing quality of the p pe The processing or smoothing roll used in my invention may have a construction generally sim= llar to a dandy roll so that it is relatively light in weight and otherwise suitable for impressing a moving wet web of paper. The surface of this smoothing roll may assume various forms and is not limited to any specific configuration of the to use, may be considered as a ventilated smoothing roll with rmpect to the operation of this roll on the wet paper web. In other words it eflectively smooths out irregularities in the Wet paper web, such as uneven distribution of fiber and filler, and the emcacy of this treatment is assured by the perforate surface of the roll.

The position of my smoothing roll on the paper machine, which machine may be a Fourdrinier or any other known type of paper machine, may

be varied appreciably. I have obtained very good results by locating this smoothing roll in rather close proximity to the dandy roll commonly used on the Fourdrinier machine. Where the dandy roll has a characteristic surface different from that of the smoothing roll and it is desired to impress that characteristic on the. final product, it is advantageous to locate the smoothing roll before or in front of the dandy roll with respect to the progress of the moving paper web on the Fourdrinier machine. When so locatedthis smoothing or processing roll, as it may be called, appears to align and smooth out the fibers in the paper web so that a substantially more uniform web surface is presented to the dandy roll for impressing of the characteristic lines. If the smoothing roll has the same, or non-conflicting,

surface configurations as the dandy roll, the relative positions of the two rolls on the paper machine is not critical and the smoothing roll may precede or follow the dandy roll. Such an arrangement may be put into practice by using a second reticulated surface processing roll instead of the usual dandy roll having straight parallel wires.

In a typical illustrative example, the use of a smoothing roll in oonjimction with a dandy roll has provided improvement in the properties of cigarette paper in the following manner: The appearance of the paper is markedly improved and in fact the appearance is so changed that the paper is considered a premium. grade as compared with paper made in the same way but without the use of my invention and heretofore recognized as high standard quality. Substantial improvements have likewise resulted in the opacity, porosity, tensile strength and stretch of the paper, the customary values of which are increased several per cent. concomitantly the production rate for the paper as as result of my invention is increased from l%-25% depending upon the type of paper produced. For example the production of the premium grade of paper may be increased by as compared with the former standard grade and where it is desired only to maintain the latter quality the productionrate may be accelerated by as much as which offers very unusual economic advantages in large scale production. Also, the amount of filler used in the paper may be appreciably reduced without deleteriously shooting the former paper quality.

The number and relative locations of rolls used in accordance with my invention is not critical and may be varied substantially to obtain different quality results and characteristics in the final paper product. Accordingly one or more, up to any desired practical number, of processing rolls may be used and the same for the dandy or decorative rolls. Likewise, various combinations or groupings of the processing rolls and dandy rolls, positioned closely adjacent each other or spaced apart, may be employed, as desired, so long as the processing rolls operate to smooth out -and rearrange generally the components of the paper web to compensate for the irregularities that commonly occur in a wet paper web as it progresses along a Fourdrinier or other type of paper machine.

In the usual operation of the processing and dandy rolls will rotate as they make contact with and impress the paper web. This rotation may be produced by traction with the moving paper web, and support therefor, as it engages the surface of the rolls; or. alternatively, one or more of the rolls may be rotated by a separate power drive connected to the roll or rolls. Likewise, the several rolls may be driven from separate drives or from a common drive.

A number of the novel features of my invention are set forth with particularity in the ap pended claims; the details of construction and mode of operation of my invention will be more fully understood by reference to the following description taken in conjunction with the accompanying drawing in which:

Fig. 1 is a diagrammatic view of a portion of a Fourdrinier paper machine showing the adaptation of the smoothing roll of my invention thereto;

Fig. 2 is a plan view, partly broken away, of a smoothing roll used in my invention, and

Fig. 3 is a plan view. partly broken away, of a dandy roll.

Referring now to the drawing and first to Fig. 1 thereof, the arrangement shown comprises a smoothing roll I and a dandy roll 2, arranged in accordance with my invention. These .two rolls are located above a moving wire belt 3 of the Fourdrinier paper machine which belt moves, in the direction indicated by the arrow. Carried on this moving belt is a continuous web of paper indicated at 4. The paper web is supported by the wire mesh belt 3 and moves therewith along the length of the Fourdrinier machine. The wire and the web first pass over a suction box shown at 5. In the embodiment illustrated one suction box located in front of the rolls and one box following the rolls is shown but it is to be understood that the number of boxes and locotions thereof may vary appreciably with difler ent machines and with difierent operating conditions.

The paper web after passing over the suction box 5, which removes from the web a substantial portion of the water in the wet pulp forming the web, comes into contact with the smoothing roll I. This roll may be of the general form shown in Fig. 2 and described hereafter. The smoothing roll i rotates as described hereinabove and makes contact with the moving paper web 4 as it passes from the suction box 5. This smoothing or processing roll I compresses the surface of the paper web 5 so as to remove irregularities in the formation of the web and generally smooth or iron out the surface of the web to provide the desired appearance and other above mentioned physical properties in the finished product. As a result of this compressing ofthe paper web 4 upon the machine wire belt 3, there is formed in the web 4 a mesh pattern or design.

Following the processing roll I, the paper web comes into contact with the dandy roll 2, which may be of known construction as indicated in Fig. 3 and described hereafter. By rotative contact with the paper web, the dandy roll 2 forms a series of parallel lines or other desired watermark on the paper as referred to above, which lines are actually fine grooves impressed into the paper by the fine parallel wires of the laid dandy roll, as is well known in the. art.

After leaving the dandy roll 2 the paper web continues toward the drying end of the machine and passes in turn over a suction box 6 which, as desired, may be of similar construction and operation to the previous suction box 5 described before. The number and location of suction boxes like the box 6 may be varied, as desired, to provide difierent' resu'ts on the paper web. The paper upon leaving the suction box 8 is carried on toward the drying rolls and other usual equipment of the Fourdrinier machine not shown herein since it may be of conventional arrangement with respect to the present invention.

The smoothing roll I shown in Fig. 2 has internal supports in the form of spoked rings I that carry a coarse wire mesh, cylindricaliy shaped, member 8. Supported by the member 8 is a surrounding flne mesh cylinder 9. These members are shown only in fragment but it is to be understood that they extend over the entire surface of the roll in the usual case. When desired the coarse supporting mesh 4 may be omitted. The perforated or ventilated construction of the outer mesh surface 8, which may be in the form of a fine mesh copper screen, permits the fluids in the paper pulp as well as the fibers. to some extent. to

flow or extend through the interstices in the surface and thereby iron out irregularities present in the surface. The wire mesh surface 9 may range for example, from 70-100 mesh, in fineness. The roll is provided with a center shaft II and a stub shaft II, the latter during operation being carried by bearings that support the roll in nonfriction rotative position. I

The dandy roll shown in Fi 3 comprises an inner supporting frame work of spoked rings l3 and an outer surface composed' of a series of closely spaced fine wire shown at II. It will be understood that the entire surface of the dandy roll that contacts the paper web will have the formation shown in the fragmentary portion at I! and [3, so a to provide uniform marking on the full width and length of the paper web. The fine wires I! are usually threaded through holes adjacent the periphery of the rings ii in well known manner. This causes the outer surface of the rings III to project a very slight distance beyond the outer surface of the wires H, as indicated in Fig. 3, and these projecting circles form spaced transverse lines in the paper. The fine wires I 2 form, the conventional fine parallel lines that characterize laid cigarette paper. 'In the final paper of th present invention these lines are superimposed over the previously formed mesh pattern, described above. In the usual case, the laid parallel lines are clearly and distinctly visible, while the mesh pattern of crossing lines is less clearly visible to the eye. Where the fine parallel lines (or laid lines as they are commonly called) are not desired in the final paper, a different form of dandy roll may be used. In this case a second processing roll such as shown in Fig. 2 may replace the dandy roll 2 and the paper so processed would have formed therein the mesh or wove pattern or design, described above, but would not have the laid lines.

While illustrative embodiments of the invention have been described hereinabove, it is to beunderstood that various modifications and changes may be made without departing from the purview of my invention. As suggested, there may be used more than one processing roll if desired or if needed for special effects on or in the paper. Likewise the location of the processing roll or rolls may be varied substantially with respect to the dandy roll. suction boxes, and other equipment normally used on a continuous web paper machine. Also the de n of the dandy roll shown in Fig. 3 may be varied widely and may, as suggested, have a roll surface like the roll in Fig. 2 depending upon the desired final paper desi n.

In the appended claims, the'term "processing roll" is used to designate the type of roll described hereinabove and characterized by a surface that functions to smooth out or compensate for the usual irregularities in a wet paper web and thereby substantially improve the quality of the final p per product. It contemplates the use of a dandy roll or other roll which itself does not accomplish the improvements attained by the conjoint use of the processing roll in accordance with this invention.

I claim:

1. In the production, from a moving wet web of pulp, of high quality cigarette paper havin numerous, fine, parallel lines extending along one dimension of the paper as a predominant characteristic design and which lines normally tend to out too deeply into the pulp and cause the pulp components to pile up adiacent the lines and present relatively transparent areas therebetween, the' improvement of controlling the depth of formation of said lines and of producing substantially more uniform and opaque areas therebetween by first forming. in said moving wet web a network of fine crossing lines that tend to distribute the pulp material uniformly over the entire area of the web and to condition the web for the subsequent treatment, and then impressing the thus conditioned wet web with said fine parallel lines of limited penetration and with consequent formation of substantially more uniform and relatively opaque areas therebetween.

2. In the production of high quality cigarette p per having characteristic fine parallel lines formed therein by impressing fine parallel wires in a moving wet web of pulp, the improvement of producing more opaque and more uniform areas between said line and of preventing said wires from cutting too deeply in the web and thereby causing the pulp material to Pile up and present irregularities adjacent the lines, said improvement comprising the step of rotatively smoothing out the irregularities in said wet web and rotatively impressing in the web a mesh design of fine lines-that tend to distribute the pulp material uniformly over the impressed area of the web and to condition said web for the subsequent impression, and then the step of rotatively impressing the thus conditioned wet web with said fine parallel wires to produce in the web said fine parallel lines with substantially uniform and relatively opaque areas therebetween.

3'. In the production of high quality, laid, translucent paper from a continuous moving wet web of paper, the improvement of a combination of means for controlling the depth of the lines in the laid paper and for producing more opaque and uniform areas therebetween, comprising first a relatively light weight skeleton roll having a wire mesh surface for rotative contact with said wet web and another relatively light weight skeleton roll having a surface of spaced, parallel, non-crossing, fine wires for rotative contact with said web subsequently to said first mentioned roll.

4. The improved method defined in claim 1, in which the water content of the moving wet web is maintained substantially constant between the preliminary treatment of the web to produce the fine, crossing lines therein and the subsequent treatment for producing the fine parallel lines.

5. In the production of laid, relatively thin. paper from a continuous moving wet web of paper, the combination of a perforate, woven surface processing roll for first smoothing or conditioning the web by rotative contact therewith,

and a laid dandy roll for rotative contact with r the conditioned web to provide the laid design therein such that the depth of the laid lines is limited and the areas between lines rendered more opaque and uniform.

6. In the production of high quality, laid, relatively thin paper from a moving wet web of paper on a Fourdrinier type paper machine having at least two spaced suction boxes, the combination of a perforate, wove, dandy roll and a laid dandy roll located between said suction boxes and in closely spaced parallel relationship, for rotative contact with the wet web, said combination being adapted to produce a substantial- 1 1 more uniform paper than is obtainable with the laid dandy roll alone.

7. A dlaphanous paper characterized by having therein a substantially indistinguishable mesh design of closely spaced crossing lines, in combination with a superimposed laid design comprising a plurality oi clearly distinguishable, more widely spaced parallel lines.

8. An improved cigarette paper having therein a characteristic laid design or fine, parallel, m

non-crossing lines, in combination with a background mesh design of line crossing lines formed in the paper.

9. An improved cigarette paper being characterized by a substantially uniform, apparent opacity and having therein, a laid design of fine, arallel, non-crossing lines which are clearly visible, superimposed over a mesh design of less clearly visible, fine, crossing lines.

JESS R. BENTON.

CERTIFICATE OF CORRECTION.

Patent N6. 2,519,800. May 25, 1915.

JESS R. ,DWTON.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 2, first column, line 23, for "as" second occurrence, read --a--; line 55, strike out "of"; and second column, line 75 for "fibers. to some extent read --fibers, to some extent, and that the ,said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 15th day of July, A. D. 1914.5.

Henry Van Arsdale (Seal) Acting Commissioner of Patents.

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