US2110032A - Process of treating wood-pulp and the like - Google Patents

Description

Patented Mar.1,19,38

PATENT OFFICE V 2,110,032 raooess or maa'rmo WOOD-PULP AND THE LIKE Harrison R. Williams, New York, my, assignor to International Paper Company, N. Y., a corporation'of New York Application May 24, 1926, Serial No Drawing.

New York,

No. 111,389. Renewed July 22, 1931 I 12 Claims.

My invention pertains to anovel and beneficial method of treating wood-pulp or equivalent ma- 1 terlal to produce therefrom a light, porous, absorbent product resembling cotton and capable of replacing the latter in many of its common uses,-

a portion of the steps of the process resulting in a somewhat different but desirable sheet product which may be satisfactorily used in various ways.

.Amain purpose of the invention is to supply a l0 process of this type which is rapid in its production of the desired results and which can be performed economically and efflciently and without objectionable, dangerous ,or otherwise unsatisfactory features.

lo In the preferred manner of carrying out the new and improved process, the wood-pulp, after having been disintegrated in water, is rendered porous and full of gas pockets or cavities,-which remain in the product even after the latter is dried, and thereafter the material may be carded to render it more fiufiy and porous, whereupon it closely resembles cotton in appearance and texture and is very highly absorbent, although it may be rendered more or less moisture-repellent if required. 7

I will now proceed to describe in detail the preferred way of practicing the new process, but it is to be borne in mind that this is by way of example only, and is not to be taken in a restricted sense,

because many changes or modifications may be incorporated in the procedure without departure from the substance-or essence of the invention as defined by the appended claims, and without the sacrifice of any of itsmaterial benefits and advantages. v a

v A suitable quantity of ordinary, dried, or only partially dried, wood-pulp is thoroughly disintegrated or finely divided in water in any approved manner, as by the use of heaters in a receptacle or other means, after which the surplus water is drained from the stock in a storage tank.

,When the solution has been brought to a point where the amount of disintegrated stock equals approximately five (5%) per cent. by weight of 5 the. water, for eachgallon of the liquid one (1) gram is added of a solution containing one thousand (1000) cubic centimeters of rape-seed oil, one (1) gram of crystallized phenol (CsHsOH) and one gram of glycerin (CsH5(OH)3), and a mechanical agitator within the vat containing the materialcauses the pulp to be thoroughly subjected to the solution. V

The contents of this vat are now slowly drawn off into the wet end or tank of a sheeting machine, and as the liquid flows into such tank, for

(C1,: ISL-2) each gallon thereof, one 1) gram of bicarbonate of sodium (NaHCOa) and one-half (V gram of potassium-hydrogen tartrate (HKC4H4Ou) or socalled potassium-acid tartrate (KHC4H40s) is added. The material is then dried in continuous sheet form without subjecting it to the actionof pressure rollers, the water being extracted partly by drainage, partly by suction, and partly by heated air, or in any other approved manner, and as the u bicarbonate of sodium gives up carbon dioxide by reason of the action of the potassium-hydrogen tartrate. thereon, innumerable pockets or gas cells are formed, which render the material soft, porous, and of a very open nature, in which form 1 it can be easily carded.

This pulp in drying does not assume the hard, solid or dense conditionwhich ordinary woodpulp takes when dried, but, owing to the gas recesses and spaces, it is porous, elastic and relatively soft and flexible, and retains the fibers of the initial pulp in more or less miscellaneous interlocking relation.

The glycerin has a tendency to soften the pulpfiber and to leave the material with an added degree of elasticity or resiliency, or flexibility, which aids or facilitates the subsequent carding operation.

Such sheet of material is suitable for use in many relations, butjin order to produce the final product therefrom, it is desirably sprayed on one surfacewith a suitable deodorant, such as formoclor, or any other appropriate deodorizing agent, preferably, but not necessarily, one incorporating chlorine.

This deodorant thus applied to the absorbent sheet of material quickly impregnates the same, so that during the subsequent carding operation it is thoroughly dispersedor distributed throughout the whole material, and in addition its slight moisture aids the carding action. v

Then this material is carded in any approved manner, and it becomes'extremelysoft and fiufiy, closly resembling cotton in very light condition, with its fibers in heterogeneous arrangement or Q disposition.

As has been indicated, this material without being carded has several satisfactory uses, such as for pads beneath-carpets and rugs, for blotters, etc., and after undergoing the carding operation, it has many uses, such as employment in the production of nitro-ce'llulose products such as explosives, a base for varnish, etc.; and. after being carded and felted, as hereinafter explained, it has many other uses, such as for hospital absorbent pads, sanitarypads, etc.

Such extremely light-and fiuffy, carded, cottony material is felted or condensed in a continuous strip of suitable dimensions, such felting interlocking the variously arranged pulp-fibers, giving the product a satisfactory degree of strength.

Thereupon, a surface of the strip of cottonlike material is sprayed with a mixture of potato or corn starch, tapioca, dextrine ,or gelatin, or the like, and alum or other water-repellent chemical, the'ratios of these two ingredients depending in large measure upon the use to II which the finished product is to be put; but,'for

example, when it is to be used for sanitary napkins, the mixture may be ninety nine (99%) per cent. starch and one (1%) per cent. alum.

Then two of these strips are placed together 20 with their starch-coated faces in contact, and these surfaces adhere together by reason of the drying of such coatings, whereupon the continuousduplex strip is severed into individual pads of, appropriate size. 7 '5 In the product, the intermediate layer of starch-treated pulp acts to bind the wholepad together and to give it adequate .strength throughout. I

The oil in the,pad,,,whose distribution and 80 action therein. has been aided, and facilitated by the presence of the phenol, reduces or localizes the-.pads extremely absorbent properties suificiently so that it may be employed advantageously,-and the oil causes a localization of. SI the absorbed liquid in the body of the pad, rather than to permit it to spread unduly at the surface. It will be understood that the oil may be added after the felt has been formed instead of'prior to its formation as in the case described.

This desirable action is increased and aided by the; intermediate starch-and-alum treated stratum, which tends to retain rather than disperse any liquid reaching it, and does not permit such liquid to be absorbed directly andimmediately through the whole thickness of the padat that point, and hence the absorptive qualities of theinterior of the pad are used 'to best advantage and without undue spreading of ,the liquid at any surface. I y This middle layer acts onlyas a deterrent in this connection, and not as a complete prevention or bar, because it, is desired-to use more or less of the whole absorbent qualities of the pad. .Stated somewhat differently, the oil in the pad .5 and the starch-and-alum layer act conjointiy, as y will bereadily understood, to cause aninterior slightly" less than that of water, which causes.

the material, after a few moments of saturation, to rise to the top of the water in a-conta'iner, and, therefore, when it is desired to dispose of agu'sed body of this material, it can be easily gotten rid of in the toilet, because it is readily flushed through the usual: trap interposed' u the pipin Where an absorbent pad is made of sheeted or stratified layers, they adhere together more or less, and hence seriously retard or hinder the required disintegration when it is to be disposed of.

In some cases, it may be desirable to incorporate in the product a material of longer fiber than that of the "pulp itself forstr'engthening purposes, and accordingly in some instances cotton or other vegetable fiber may be mixed with 10 the wood-pulp, either before or after the carding operation.

' Although in this patent I have referred more specifically to wood-pulp, it is to be understood that the process is susceptible of satisfactory and beneficial employment with other more or less analogous vegetable materials, and even though the term wood-pulp be used in the followin claims, it may be construed broadly enough to cover equivalent materials. v

In the manufacture of cotton batting, wadding, etc., the glaze or finish provided bythe binding starch is applied to one or more exte-. rior surfaces of. the product, which is used in that condition, rather than associated with another-like portion of the'product, to make an intermediate or middlelayer of this character.

It is to be understood that the invention is not restricted or limited to the precise ingredients specified, because all of these and other factors entering into the process may be modified within substantial limits'without departure from the invention and the advantages which accrue from its employment, and one or moreof the ingredients specified may be, omitted in some instances. 3

I claim:

1. The process of treating wood-pulp or similar material, consisting in treating the woodpulp with an oleaginous material having the property of localizing liquid absorption thereby, 40 carding-the pulp; felting the carded pulp, and forming a stratum within the felted pulp adapted to retard the penetration of liquid from oneside. of the felt to the other side of the felt and insure more complete distribution of said liquid throughout the pad. I

2. The process of treating wood-pulp or similar material, conmsting in adding to the woodof liquid from one side of thefelt to the other side of the-felt and insure more-complete dise tribution of said liquid throughout the pad.

3. The process of treatingwood-pulp or'similar material, consistingdn .disintegrating the wood-pulp in water, reducing the volume of water until five-(5%) per cent. of its weight is the disintegrated pulp, adding to each gallon of such liquid approximately one (1). gram of a solutioncomposed of about one thousand (1000) cubic centimeters of rape-seed oil, approximately one (1) gram of crystallized phenol and about one (1) gram of glycerin, agitating the mixture to cause the pulpto be thoroughly subjected to the solution, drawing off such solution and adding to each gallon thereof about one (1) gram of bicarbonate of sodium and approximatelyhalf A a gram of potassium hydrogen tartrate, sheeting the pulp; and drying-the pulp unde heat.

4. The, process of treating wood-pulp or similar material, consisting ln-disintegrating the wood-pulp in water, reducing the volume of water until five per cent. of its weight is the disintegrated pulp, adding to each gallon of such liquid approximately one (1) gram of a solution composed of about one thousand (1000) cubic centimeters of rape-seed oil, approximately one (1) gram of crystallized phenol and about one (1) gram of glycerin, agitating the mixture to cause the pulp to be thoroughly subjected to the solution, drawing off such solution and adding to each gallon thereof about one (1) gram of bicarbonate of sodium and approximately half a gram of potassium-hydrogen tartrate, sheeting the pulp, drying the pulp under heat, and carding the dried pulp.

5. The process of treating wood-pulp or similar material, consisting in disintegrating the wood-pulp in water, adding rape-seed oil, phenol and glycerin thereto, then adding bicarbonate of sodium and potassium-hydrogen tartrate thereto, then sheeting and drying the pulp, and then carding the dried pulp.

6. The process of treating wood-pulp or similar material consisting in disintegrating the dried pulp in water, adding in the same batch of pulp in water, chemicals which interact to form a leavening gas, and then drying the pulp.

'7. The process of treating wood-pulp or similar material consisting in disintegrating the dried pulp in water, adding in the same batch of pulp in water, chemicals which upon heating liberate carbon dioxide gas, and then drying the pulp.

8. The process of treating wood-pulp or similar material consisting in disintegrating the dried pulp in water, adding in the same batch of pulp in water, a salt of carbonic acid and an acid tartrate salt, and then drying the pulp.

9. The process herein described which consists in disintegrating wood pulp in water, forming the disintegrated pulp into a continuous sheet, ab-

stracting water from the material of .said sheet and drying the same to constitute a relatively soft sheet, with the fibres thereof relatively loosely united to each other, carding such sheet, condensing the carded material to form a continuous strip of felted material and severing the strip into individual pads.

10. The process herein described which consists in forming wood pulp into a sheet with the individual fibres thereof relatively loosely united to each other, carding such sheet, condensing such carded material to form a continuous strip of felted material, applying aqueous starch to a surface of the material, uniting the starch coated face of the strip with a second strip of the felted material, so that said strips are caused to adhere by reason of drying of said coating and severing the continuous duplex strip into individual pads.

11. The process herein described which consists in carding a sheet of wood pulp having the individual fibres thereof relatively loosely united to each other, condensing such carded materials to form a continuous strip of felted material, applying aqueous starch to a surface of the material, uniting the starch coated face of the strip with a second strip of the felted material, so that said strips are caused to adhere by reason of drying of said coating and severing the continuous duplex strip into individual pads.

12. The process herein described which consists in carding a sheet of wood pulp having the individual fibres thereof relatively loosely united to each other, condensing such carded material to form a strip of felted wood pulp and associating with said wood pulp a vegetable material of longer fibre than said wood pulp to strengthen the resultant product.

HARRISON R. WILLIAMS.