US1973722A - Paper and method of making same - Google Patents

Description

38 1934. w c NASH PAPER AND METHQD OF MAKING SAME;

Filed May 16, 1932 M ZN Q a F J l 1 W K H H 0 0 \N I Z Patented Sept, 18, 1934 I 1,973,722

UNITED STATES PATENT OFFICE 1,973,722 PAPERFAND METHOD OF MAKING SAME William C. Nash, Neenah, Wis., assignor to Seaman Paper Company, Chicago, 111., a corporation of Illinois Application May 16, 1932, Serial No. 611,453 14 Claims. (Cl. 92-39) This invention relates to improvements in pasirable natural characteristics of the kapok I per and a process for making the same from a and/or cotton-silk fibres and yet has appreciable pulp comprising fibres of different specific gravistrength. In my process of making this paper, ties and refers specifically to the production of a the beating and felting difilculties'heretofore as F a paper and the process of making the same from perienced have been substantially eliminated. W a pulp comprising relatively light fibres such as Although my process is particularly useful in kapok,cotton-silk or the like, and relatively heavy making paper from kapok and/or cotton-silk fibres, such as rag fibres or those used in the mak-, fibre in conjunction with a fibre of less brittle and ing of ordinary paper. less water resistant qualities, it is to be understood H m The fibres of the kapok and/or cotton-silk famthat broadly my invention may be used tomake a ily in their natural state possess characteristics paper from the pulp comprising any fibres of difwhich make them exceedingly useful particularly ferent specific gravities. as heat insulating medium. They are substan- Further objects and advantages of my inventially impervious to moisture, brittle, and of rela tion \vill be apparent from the accompanying r,

tively great bulk per unit of weight. In bulk form drawing and following detail description. 9 they have already been used for heat insulating In the drawing, Fig. 1 is a diagrammatic side purposes and because of their moisture resistant elevational view, parts being shown in section of for life preservers in lieu of cork 'I'helr charac- Fig. 2 is fan enlarged fragmentary sectional teristics as to brittleness have made them desiraview of the product embodying my invention. ble for use in pillows and mattresses. 6 Referring in detail to the drawing, 1 indicates However, the very characteristics of these fibres a conventional beater provided with a beating which make them desirable for the above menr011, t h mounted upon Shaft A tioned purposes have heretofore rendered them duit 3 may connect the beater 1 coupled in units 25 substantially uselessinpaper or felted form. Bewith stock chest 4. The stock chest 4 may be in reducing said fibres to pulp suitable for paper 5 which may carry a plurality of beating vanes mairmg since it is substantially impossible to wet or a ms A bevel gear 7 y be u ted N the express purpose-of eliminating the brittle inn r Walls of the stock chest 4.

to absorb water and be converted into suitable to t lower DOItiOII of said Stock ehesthe paper making pulps, However, a, paper made discharge 13 0f the pump may connect into the from these fibres does not possess those characupp portion of the Stock Chest, the P mp 11 teristics of moisture resistance and brittleness being adapted to circulate the p p W th n the which are inherentinthe natural state and which Sleek Chest, the importance of hich Will be make said fibres excellent for use as aheat innafte mo e u ly brou t utsulating material. A stock pump 14 may be positioned adjacent A further difiiculty which arises in making pae tock chest 4 and the intake 15 of a d p mp as per from fibres of t kapok and/or tt k may connect into the lower portion of said stock 109 family is that after the fibres have been brought CheSt- The P 1 drawn f om e Stock Chest to a suitable pulp form and the same are introthrough the intake 15 may be forced through duced upon the forming wire of the paper makpump 14 in pip 16 wh may c nn ct into lng machine, said fibres, due to their brittle charthe upper portion of a conventional stock reguell acteristics do not properly intermesh or interlator 17. The stock regulator 17 may be protwine with one another to produce a resultant vided with overflow pipe 18 which may connect paper which has desirable shock, tensile, and into the upper portion of the stock chest 4. In abrasive strength. addition, the stock regulator may be connected By the use of my invention a paper may be to pipe 19 which may connect at its opposite made which possesses substantially all of the deend into the inletlof pump 20. A pipe 21 may l lii also connect into the inlet side of pump 20 and may be adapted to withdraw water from the save-alls (not shown) of a conventional Fourdrinier machine 24. The discharge 22 of pump 20 may connect into head box 23 of the paper making machine 24,. the head box 23 being of conventional construction and being provided with baflles 25.

The pulp from the head box 23 may be discharged upon wire 26 of the paper making machine 24, said wire, as is well known to anyone skilled in the art, travels in an endless path substantially the entire length of the wet end of the Fourdrinler machine. The wire 26 in travelling toward the head box passes over guide rolls 27 and around breast roll 28, thence over table rolls 29. I

In carrying out my invention 1 may introduce a quantity of fibrous material, such as that used in the making of ordinary paper, into the beater 1. For instance, said fibres may comprise previously washed raw rag fibre. The fibres thus introduced may be mixed with water to form a pulp, and during the beating operation, a quantity of relatively light fibres such as those of the kapok and/or cotton-silk family may be introduced and the beating action continued.

As has been hereinbefore explained, to properly reduce fibres such as kapok and/or cottonsilk to pulp form considerable difficulty may be experienced. The fibres tend to float upon the surface of the water and may persistently defy all efforts to reduce the same to pulp. The fibres when acted upon by the beating drum merely ball-up and unless the beating action is continued with violence for a relatively long period, said fibres cannot be reduced to pulp form. However, this violent and prolonged beating action appears to have a detrimental effect upon the fibres, rupturing them or partially disintegrating them. The effect upon the paper made from these fibres is to the useful characteristics of the natural fibres, the paper being moisture absorbent, and of relatively dense structure and possessed of none of the high heat insulating qualities of the natural fibre.

As has been hereinbefore described, the pulp.- ing operation may be facilitated by the use of chemicals, but again the natural characteristics of the fibres are lost and, hence, the usefulness of the resulting product impaired.

However, when the kapok and/or cotton-silk fibres are beaten with the usual water absorbent paper making fibres, they intertwine and intermesh with each other and the whole may readily be reduced to pulp form. In so intertwining'and intermeshing the heavier fibres cushion and protect the lighter fibresand consequently permit thorough beating and wetting of the whole without destruction to the structure or change in the material characteristics of the lighter fibres.

As an example, raw rag may be washed and beaten until reduced to half stuff" at which time the'fibres may be loaded into the beater 1 and mixed and further beaten with kapok. fibre until the desired pulp is formed. The rag fibre may comprise 35 percent by weight whereas the kapok may comprise the remaining percent. It is to be understood, of course, that I do to the materials nor proportions given in the above example, since my invention is broadly directed to a paper made from a fibrous pulp comprising fibres of different weight, and the process of making said paper.

eliminate substantially all of pool or pond 35 is After the pulp has been properly formed in the beater 1 said pulp may be passed through pipe 3 to the stock chest 4. By the provision of the revolving blades or vanes 6, said pulp is maintained in an agitated condition while in said stock chest, and a local circulation of pulp from the bottom of the stock chest to the top thereof is established by pump'll. If kapok and rag fibres are used the kapok fibres, being much lighter and having less absorptive properties than the rag fibres, will tend to rise and the heavier, thoroughly Wet rag fibres will tend to sink. Consequently, it is of importance, in order to prevent such separation, to maintain the pulp in an agitated condition and not permit the pulp to become stagnant.

The pulp may be continuously withdrawn from the stock chest 4 through pipe 15 and may be forced by pump 14 through pipe 16 to stock regulator 1'7. The excess pulp entering the regulator 17, which may be of conventional construction, may be returned to the stock chest 4 through pipe 18. The remaining pulp may be withdrawn from regulator 17 by pump 20 through pipe 19. The intake of pump 20 may also be connected to pipe 21 which, in turn, may conduct the water from the save-ails" (not shown) of the machine 24.

The pulp passing through pump 20 from pipe 19 and the waterdrawn from the save-alls" is forced through discharge pipe 22 into head box 23 which may be of conventional construction, being provided with baflies 25 which cause the pulp to fiow upwardly through compartment 30, downwardly through compartment 31 and upwardly through compartment 32, over the table board 33 of the head box and onto apron 34.

As a feature of my invention the axis of the breast roll- 28 may be lowered from its usual position as may also the axes of the table rolls 29, the arrangement being such that the wire 26 in travelling forwardly from the breast roll passes upwardly in an inclined direction. The distance of inclined travel of the wire 26 from the breast roll may depend upon the type of stock to be felted. For example, if the stock comprises 35 percent by weight of raw rag fibre and 65 percent by weight of kapok fibre, good results have been obtained by causing the wire 26 to travel along an inclined path for a distance of approximately five feet from the breast roll. It is to be understood, of course, that I do not wish to be limited to the specific example mentioned since said constants of operation may be varied within wide limits dependent upon the stock worked.

By the provision of the lowered breast roll a formed having appreciable depth for instance, 10 to 12 inches using the pro.- portions of stock mentioned above. It will be observed that the pulp from its period of formation in the heater 1, through stock chest 4, regulator 17, pump 20 and head box 23, is maintained in an agitated condition and is not permitted to stagnate. The reason for this is to prevent settling of the heavier fibres. However, when the stock enters the pool or pond 25, the same being in a more or less quiescent state, the fibres are permitted to separate, the heavier fibres descending to the apron rising to the surface. Simultaneously with the separation of the fibres the wire '26 is shaken thereby disturbing the lower surface of the pond and interlocking the heavier fibres.

The action which undoubtedly takes place is 34 and the lighter fibres that, the heavier fibres in settling carry a plurality of the lighter fibres down with them; The shaking action tends to release said lighter fibres and also permits the descent of heavier fibres in the body of the .pond. Depending upon the period of settling, and the amplitude and frequency of vibration of the shake, will depend the characteristics of the resultant paper. If the period of settling is relatively long and the shake relatively violent, a more perfect separation will occur and the resultant paper will have a relatively clear line of demarkation between the layers of fibres. If the settling period is short and the shake relatively gentle, the line of demarkation will be relatively shadowy. However, in either case, the heavier fibres, having relatively good bonding power will tie or intermesh,

adjacent the lower surface of the resultant web,

with the ends of the lighter fibres, little or no mutual bonding power.

Of course, I do not wish to be limited to the above theory or hypothesis, however closely it may conform to the resultant facts, since my invention is broadly directed to a paper conwhich have structed from pulp comprising fibres of diverse characteristics and paper.

method of making said To vary the length of the settling period, the apron 34 may be extended varying distances forwardly over the wire 26 from the breast roll 28. Of course, for relatively high wire speed the apron may be lengthened whereas for relatively slow speeds the same may be shortened, thereby maintaining the settling period substantially constant for variations in wire speed.

If fibres of the kapok or cotton-silk family are used, a rotary slice 36 or a relatively stiff shower (not shown) is preferable to the usual slice since it is characteristic of this class of fibrous material to ball-up if brought into contact with the usual slice of the dam or weir type.

Referring particularly to Fig. 2, an exaggerated diagrammatic sectional view of a fragmentary portion 37 of a web formed from kapok and rag fibres is shown. The lowermost portion of said web may comprise rag fibre 38, the proportion of rag fibre decreasing more or less abruptly upwardly from said lower surface. Above approximately the lower quarter of the thickness of the web 37 substantially no rag fibre appears and the upper three-quarters 39 is substantially pure kapok fibre. Many of the kapok fibres comprising the central and upper portion of the web may be tied or intermeshed at their ends in the ,layer of rag fibre 38 at the lower surface of the web, as indicated diagrammatically at 40.

It can readily be seen that a web or sheet of this construction possesses throughout a substantial portion of its thickness the characteristics of, for instance, kapok or cotton-silk, whereas, the rag layer imparts strength to the entire structure. Hence, the web or sheet as a whole may be used for insulating purposes since moisture will not penetrate the same from the lower surface except to the depth of the rag fibre Whereas the opposite or top surface will be substantially impervious to moisture.

It is to be understood, of course, that although the process of my invention is particularly adaptable for felting such fibres as kapok and cottonsilk in conjunction with fibres having diverse properties, I do not wish to be limited thereto since my invention broadly contemplates a paper composed of pulp having fibres of different phys- 109.1 characteristics as to weight, and a process of making such paper.

By the term cotton-silk as used in the specification and claims is meant, those fibres of the cotton-silk or kapok family technically known as Asclepediadacea particularly the Asclepias division of said family, and by the term cotton silk as employed in the specification and claims I'intend to include as equivalents relatively light fibres having physical characteristics similar to cotton silk or kapok fibres.

By the use of the expressions, relatively heavy fibres, relatively pliable fibres, absorbent fibres is meant fibres having characteristics similar to alpha cellulose, sulphite, sulphate, burlap, hemp, rope fibres or the like.

I claim as my invention:

1. A paper comprising cotton-silk fibres and relatively heavy fibres characterized in that the relatively heavy fibres lie adjacent a surface of the paper, and the cotton-silk fibres constitute substantially the entire remaining thickness of the paper.

2. A paper comprising cotton-silk fibres and relatively heavy fibres characterized thatithe cotton-silk fibres constitute the major-portion of the thickness of the paper and their'elatively heavy fibres lie adjacent a surface of the paper and serve as a reenforcing medium for the cotton-silk fibres.

3. A substantially waterproof paper compris-" ing a layer of cotton-silk fibres and a layer of heavier fibres.

4. A substantially waterproof paper comprising a layer of cotton-silk fibres bonded to a layer of heavier fibres.

5. A substantially waterproof paper comprising a relatively thick layer of cotton-silk fibres and a relatively thin layer of relatively heavy fibres.

6. A substantially waterproof paper comprising a relatively thick layer of cotton-silk fibres intermeshed with a relatively thin layer of fibres of raw rags.

7. A process of making paper from relatively heavy and relatively light fibres which comprises, beating said fibres together in the presence of an aqueous vehicle to form a pulp, passing said pulp to the head-box of a paper making machine, agitating said pulp during its passage from the beater to the head-box, passing said pulp from said head-box to the forming wire of said paper making machine, maintaining a relatively quiescent pool of said pulp upon said forming wire whereby to cause said fibres to separate, and after a predetermined degree of separation withdrawing the liquid carrier from said pulp.

8. A process of making paper'from relatively heavy and relatively light fibres which comprises, beating said fibres together with a liquid carrier to form a pulp, passing said pulp to the head-box of a paper making machine, agitating said pulp during its passage from the beater and through the head-box, passing said pulp from said headbox to the forming wire for said paper making omachine, maintaining a relatively quiescent pool of said pulp of appreciable depth upon said forming wire thereby causing said fibres to separate, and after a predetermined degree of separation withdrawing the liquid carrier from said pulp.

9. A process of making paper from relatively heavy and relatively light fibres which comprises, beating said fibres together with a liquid carrier to form a pulp, passing said pulp to the head-box of a paper making machine, agitating said pulp and moisture in the specification and claims during its passage from the heater and through the head-box, passing said pulp from said headbox to the forming wire of said paper making machine, maintaining a relatively quiescent pool of said pulp upon said forming wire thereby causing said fibres to separate by gravity, agitating the heavier fibres adjacent the bottom of the pool and withdrawing the liquid carrier from the pulp.

10. A stock capable of being felted consisting of a mixture of cotton-silk fibres and relatively heavy fibres, contained in an aqueous vehicle, the heavier fibres intermeshing with said cottonsilk fibres and functioning to hold said cotton-silk fibres in suspension.

11. The herein described method of making sheets of heat insulating character comprising the steps of mixing kapok with a relatively heavy fibre and beating the same without substantial destruction of the kapok fibres and without substantially changing the characteristics thereof, withdrawing the mixture from thebeating zone and introducing the same to a stock chest and there vigorously maintaining the mixture in a state of agitation whereby to prevent the lighter kapok fibres from substantially separating from the relatively heavy fibres, withdrawing the mixture from the stock chest zone and introducing the same to a separation zone where the heavier fibres stratify from the kapok fibres, and thereafter sheeting the thus stratified and intertwined structure whereby to provide a sheet structure comprising an upper layer of kapok fibres retaining substantially their original characteristics and a lower supporting layer of the relatively heavier fibres.

12. The herein described method of making a heat insulating sheet comprising the steps of introducing kapok and relatively heavier fibres, such as rag fibres, to a beating zone and there treating the same without substantially changing the characteristics of the kapok fibres, leading the mixture to a stock chest zone and agitating the same with sufficient violence to prevent substantial separation of the lighter kapok fibres from the heavier fibres, thence leading the mixture to a stratifying zone where the kapok fibres are permitted to rise and the heavier fibres are permitted to gravitate and form a relatively thin strengthening backing film for the kapok fibres, and thence sheeting the same whereby to provide a heat insulating sheet with the substantially unimpaired kapok fibres in one strata and the heavier fibres intertwined therewith and constituting a supporting sheet therefor.

13. The step in the process of manufacturing heat insulating sheets comprising the introduction of a mixture of kapok and relatively heavier fibres to a quiescent zone and there permitting separation of said fibres according to their specific gravities and thereafter sheeting the same in their thus stratified condition whereby to form a structure comprising a lower film of the relatively heavier fibres constituting a supporting film and an intertwined upper strata of kapok fibres possessing substantially their orig nal insulating characteristics.

14. A process of making paper from relatively heavy and relatively light fibres, which comprises beating said fibres together in the presence of an aqueous vehicle to form a pulp suspension, causing separation of said fibres within said pulp suspension by charging same to a relatively quiescent pool whereby the heavy fibres gravitate to the bottom, maintaining the pulp suspension in an agitated condition until separation occurs, and withdrawing the aqueous carrier from said pulp to form a paper in which the relatively heavy fibres are concentrated adjacent the lower surface thereof.

WILLIAM C. NASH.

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