US2073682A - Processes of treating vegetable fibrous material for the production of cellulose fibe - Google Patents

Description

March '16, 1937. F. R. CHESLEY, JR 7 PROCESS OF TREATING VEGETABLE FIBROUS MATERIA FOR THE PRODUCTION OF CELLULOSE FIBER Invnror; Franklin Rchesle Filedv June 15 1935 Patented Mar. 16, 1937 i I UNITED STATES. PATENT OFFICE PROCESSES OF TREATING VEGETABLE' FIBROUS MATERIAL FOR 'THE PRO- DUCTION F CELLULOSE FIBER Franklin R. Chesley, In, Saco, Maine Application June 13, 1935, Serial No. 26,404 11 Claims. (01. 92947) This invention relates to improvements in the ing complementary fluted rollers. The fiber thus production of cellulose materials, and the object treated is subjected to the operations of dressing thereof is broadly to provide a process for treatand roving and when used for textiles is spun by ing vegetable fibrous material, including woods a wet spinning process.

especially coniferous woods, in such a manner as Ramie fibers when. produced by usual proc- 5 to remove the resins and gums from the fibrous esses have serrated or toothed edges which prematerial without aflecting the cellulose constitusent a hairy appearance and when the fibers are ents thereof, whereby the cellulose, whether in the rubbed together in subsequent treatments, such a form of fibers or otherwise, may be treated by as spinning, they become torn and also are easily l0 usual methods and/or machines to produce ecobroken when bent. nomically and profitably materials used in the It is believed that the serrated or hairy characvarious industrial arts in which cellulose is em- -teristics of the fibers are caused mainly by the ployed. extraction of the waxes which are contained in The process herein described is adapted to the the natural fibers, and one of the principal objects treatment of vegetable fibrous materials, include oi' the invention is to provide a process of treat- 15 ing plants, fiber-producing shrubs, and the like, ment of the fibers of ramie, and other fiber-bearfor the production of cellulose fibers used in the ing plants of this character, in such a manner textile arts, and may also be employed in the' that the waxes will not be removed, from the production of cellulose pulp adapted for trea'tfibers, thereby not only preserving their lustrous 2 ment to produce other products, such as paper, appearance, but also preserving the natural or when nitrated to produce the bases for expiostrength of the fibers. .This is accomplished in sive compositions. the present invention by subjecting the fibrous The invention includes the process of decortimaterial, such as the stalks of ramie, hemp, flax, eating and degumming fiber-bearing plants/such or other plants, preferably cut into desirable as as ramie, flax, jute, sisal hemp, etc., by means i staple lengths, to the action of an aqueous, weak 5 of which the resins and gums are removed, the alkaline, solution in the presence of aluminum, bark released in such a; manner that it can be capable of dissolving the gums and resins coneasily separated and the fibers individualized tained in the fibrous material, but which is inwithout destroying or deteriorating the cellulose capable of dissolving the waxes contained in the constituents of the material. fibers, the solution being of insuflicient causticity 30 By the present process relatively inexpensive to afiect the cellulose of the fibers. Inasmuch as materials and apparatus may be employed and the individual fibers of such plants are in the the time required for treatment greatly shortform of a single cell comprising mainly cellulose, ened as compared with other processes which are treatment by the present process results in the commercially used. production of fibers in which the waxes are re- 35 In view of the fact that it has heretofore been tained, the strength of the fibers preserved, and diificult to produce ramie fibers which can be their lustrous appearance maintained. used in the textile industry and which when used i Usually the fibers of ramie, flax, hemp, and the requires special machinesfthe present process like, are bleached subsequently to the decorti- 40 will be described specifically in relation to deeating and degumming process. By the present 40 corticating and degumming of ramie and the invention decortication, degumming, and bleach-=- like, and so individualizing the fibers thereof in ing may be performed concurrently by the inclua relatively inexpensive and efiicient manner as to sion of a bleaching chemical in the solution which prepare the fibers for direct treatment by usual effects the decortication and degumming of the machines employed in the treatment of cotton.v fibrous material, a. suitable neutralizing agent 45 In the usual treatment of ramie, the ramie being employed to remove the excess of bleaching 'stalks are decorticated by being fed into a mamaterial. Alternatively, the bleaching of the chine havin'g rapidly revolving blades which break fibers may be made subsequent to the decortlcathe stalks into small pieces andleave the bark tlon and degummlng as will hereinafter more and fiber in long ribbons, part of the gum being fully appear. 50

squeezed out by the heaters. The ribbons are Any suitable apparatus may be employed for then subjected to the action of caustic'soda soluperforming the present process. An illustrative tion in a heated closed vessel or boiling'kier under apparatus is shown in the accompanying drawsteam pressure. After having been boiled a. ing, in which,

sufficient time to remove the gum, the material Fig. 1 is a view, mainly in vertical section, of 55 is lifted out, the alkali neutralized and the fiber a series of kiers,and a suitable basket, to contain thoroughly washed to remove all traces of the the material, supported uponatrolley and adaptchemicals, and the fiber finally dried. I 'hereed to be transferred from one kier to another; after, the fiber is softened by passing it through and,

a breaker, usually in the form of a machine hav- Fig. 2 is a similar view of suitable apparatus 60 adapted to be employed when the fibers are bleached subsequently to decortication and desumming.

In the performance of the process vby the apparatus illustrated herein, the fibrous stalks l of ramie, hemp, flax, or the like desirably are first cut to desirable staple lengths, and placed in a basket 2 having a reticulated or perforated bottom and sides and which is suspended by suitable supports 3 from a cable 4 which passes over a pulley 5 depending from a trolley 6 which is mounted to travel upon a track 1 extending longitudinally over a series of receptacles or kiers. A series of such kiers 8, 9, I 8 and I I, are employed, all of which may be 1 of substantially identical construction and located below the plane of the fioor l2, the upper edges of the kiers desirably being flush with the fioor. An aqueous alkaline solution containing aluminum, either in the form of finely divided metal or in the form of a sulphate, is introduced into the first of the kiers 8.' I have found by experiment that a weak alkaline solution containing the following ingredients in substantially the proportions statedgives most excellent results,

Fresh water gallons 100 0 Tribasic sodium phosphate -pounds 719 Soda ash do 62.5 Aluminum sulphate do 7.8

I have also found that finely divided metallic aluminum may be substituted in the solution for the aluminum sulphate in the proportion of approximately 23.3 ounces of aluminum per one thousand gallons of water.

The chemicals may be added to the water when cold and before the basket, containing the material to be treated, is introduced, but better results are obtained when the material to be decorticated and degummed is placed in the water and the temperature then raised to the boiling point, which is between two hundred degrees F. and two hundred twenty-five degrees F., and the chemicals then added.

45. Any suitable means may be provided for maintaining the solution at a boiling temperature. Desirably steam is forced through a pipe l3 and suitable branches I 4 therefrom leading through the bottom of the kier into the material at a sufficient rate to maintain the temperature of the solution at a boiling point, and also to maintain a mild agitation of the material by the ebulition of the steam passing through the solution. The boiling is continued for from approximately fifteen to approximately one hundred thirty-five minutes depending upon the following conditions:--

1. If the ramie were in its natural form, 1. e., about four-foot lengths, the time allowed is about one hundred thirty-five minutes, after the solution has come to a boil, and if-cut to staple lengths less than nine inches the time allowed is approximately one hundred five minutes.

2. Flax when boiled in said solution for fortyfive minutes is found to be suificiently decorticated for use.

3. Other fibrous materials may be allowed such suitable timewithin the aforementioned range of from fifteen to one hundred thirty-five minutes,

according to their condition, and quality, to assure complete degumming.

The solution and material may be observed from time to time and when the decortication and degumming of the process is observed to be complete, bark and other materials which float upon the surface may be skimmed off.

The basket may then be raised from the kier 8 and transferred to and deposited in the kier 9 and subjected to washing. The washing in this kier desirably may be accomplished by forcing hot water through a pipe l5 and branches l8, having suitable valves l1 therein, to fill the kier 9 and continuously to overflow therefrom through an outlet pipe l8. Desirably the basket containing the material is transferred from the kier I8 successively to similar kiers or washing tanks l8 and H where fresh hot water is introduced from the pipe IS in like manner.

The action of the hot weak alkaline solution in the kier 8 serves to dissolve the resins and gums of the fibrous material, thereby detaching the fibers from the box andalso liberating the fibers from each other, so that they are individualized. It is believed that the presence of aluminum or an aluminum salt facilitates and speeds up the action of the alkalis in precipitating the tannic constituents of the fibrous materials and also facilitates the action of the alkali upon the soluble gums and other constituents of the fibrous 1 material, and also in removing certain of the pigments as the fibers when thoroughly washed are substantially colorless.

If desired the-fibers may be bleached by the present process during the decorticatlon and degumming thereof by introducing into the solution contained in the kier 8 a suitable bleaching material.

In the treatment of ramie sodium hypochlorite may be employed as a bleaching agent in the proportion of approximately two ounces of sodium hypochlorite to one gallon of the solution. In such instance the fibrous material must be washed by a bath method, there being introduced between the second and third baths a boiling solution made by adding one ounce of concentrated sulphuric acid to each gallon of water in the bath.

In thus performing the bleaching concurrently with decortication and degumming, the apparatus shown in Fig. 2 is employed in which the basket 2 is carried in like manner by supports 3 upon cables 4 which pass over a pulley 5 depending from a trolley 8 upon the track I, the steam being supplied to the kier 8 through the pipe I! and branches M in the manner above described. In this apparatus the kiers 9, I8 and H are each supplied with hot water through a pipe l6 as aforesaid, but an additional kier I9 is interposed between the washing kiers l0 and II to contain the acid solution for neutralizing the bleaching agent. The proper acid solution may be introduced into the kier l9 through a pipe 28 having a valve 2| therein and the acid solution heated by steam introduced through a pipe 22 having branches 23 leading through the bottom of the tank.

When the decorticated and degummed fibers contained in the basket 2 have been suitably washed in the kiers 9 and I0 they are transferred in the basket to the kier l9 where the material is permitted to stay in the acid for a period of five minutes or more, after which the basket is transferred to the kier II where the bleached material is thoroughly washed, after which it desirably is thoroughly dried by a forced draft of heated air. The bleached material is then ready for mechanical processing.

The material when processed in the manner above described may be treated in usual cotton the machines.

7 2,078,682 'mixing and carding machines and spun, woven,

usual processes heretofore employed in that the degumming is so complete that usual carding machinery may be employed without detriment to This is particularly true of carding in which it has heretofore been deemed impossible to card ramie because the amount of gums or resins, which are retained by the fibers, will in a short time accumulate upon the card clothing and clog the machinery not only injuring it, but in many instances producing such massing of the fiber as to injure the machine. The fibers when treated by the process herein described are substantially free from serrations or hairs. Their flexibility is retained and breakage by abrupt bending is substantially eliminated. The fibers ,have greater tensile strength and can be spun into threads which present a lustrous appearance and when woven produces a very flexible fabric of unusual strength having the appearance of high grade linen. The 'fibers can be readily and uniformly dyed either before or after spinning.

A further important feature of the invention "comprises the manufacture of absorbent cellulose materials from ramie, and other fibrous materials, of the character above described, by the elimination of such waxes and oils as are retained in the fibers. This may be accomplished by treating the fibers produced by the process aforesaid with a suitable solvent, such as naphtha, for the waxes and oils, retained in the fibers.

It is found that when the ramie fibers are thus treated they have far greaterabsorbent qualities than cotton; or other usual fibrous material employed as absorbents. The product thus obtained by the 'present process is especially suitable for use in surgical bandages, wicks, and

other purposes in which the highly absorbent characteristicsof the fibrous material are advantageous.

Hemp, flax, jute, sisal, and other fiber-bearing plants may also be treated by the same process and with the same chemicals, difiering only from the process of treating ramie in the period of immersion in the heated solution. The preparation o'fthe fibers from such plants by the present process eliminates numerous treatments heretofore believed to be necessary in the preparation of the fibers for spinning, etc.

Another important feature of the present invention is the application of. the present process to the treatment of wood, especially coniferous wood, in the production of cellulose pulp for use in paper making, or other industrial arts, in-

cluding cellulose bases for explosive compositions.

In theproduction of paper pulp, wood chips have heretofore-been usually treated by an acid or a caustic alkaline process for the purpose of reducing the chips to a cellulose composition, the

chips being then broken up, either by crushing,

beating, or by projecting the same forcibly against a, steel plate. The treatment of the chips in such acid or caustic solution requires twentyfour hoursormore and in such treatment the chips are boiled in the solution under high pressure involving large expense and requiring a very considerable amount of time. By the present process the wood chips are treated in the heated aqueous weak alkaline solution of the character above described at ordinary pressureathe solution being maintained at substantially the boiling, point by the introduction. of steam under pressure to maintain an ebulition in the kier containing the material. The time required to reduce the chips to the cellulose composition may vary from nbt less than three hours to not more than seventeen hours, according to the character of the wood being treated. The chips may then be reduced to pulp formby similar mechanical methods. The product will then be in the form of a pulp which may be used in the manufacture of paper. If the paper pulp thus produced is then thoroughly washed and again treated with the same solution, under the same conditions, for

approximately two hours, further reduction will other types of apparatus may be used in the performance of the process.

Having thus described the invention, what is claimed as new, and desired to be secured by Letters Patent, is:

1. The process of treating vegetable fibrous material which comprises subjecting the fibrous material to immersion for a suitable period of time in an aqueous weak alkaline solution, comprising a major portion of tribasic sodium phosphate and a minor portion of an aluminum-containing substance, capable of dissolving gums and resins within the fibrous material and of precipitating tannic substances contained in said fibrous material without aifecting the cellulose of the fibers, and thereafter repeatedly washing the fibers to remove the chemicals and'the foreignmaterial which-have been-released by the action of the solution.

2. The process of treating vegetablefibrous material'which comprises subjecting the fibrous material to immersion for a suitable 'period of time in a heated aqueous weak alkaline solution comprising 'a major portion of tribasic sodium phosphate and a minor portion of aluminum sulphate, capable of dissolving the gums and resins contained in said fibrous material, but incapable of dissolving the waxes contained in said fibers, and of insumcient caustici ty to affect the cellulose of the fibers, introducing steam into the solution to maintain the heated solution at substantially its boiling point, and to maintain ebulition of said liquid effective to facilitate. the 'solventgaction of said solution.

3. The process of decorticating'and degum- 'ming fibrous plants which comprises immersing the fiber-bearing portions thereof for a suitable time in a heated aqueous weak alkaline solution, comprising a major portion of tribasic sodium phosphate and a minor portion of soda ash in the presence of an aluminum-containing substance, capable of dissolving the gums and resins contained in the fibrous material, but of insuificient causticity to affect the cellulose of the fibers.

and individualizing the fibers thereof which comprises steeping or boiling the fiber-bearing portions thereof, cut to desirable staple lengths, for a suitable period of time, in an aqueous weak alkaline solution, comprising a major portion of tribasic sodium phosphate and a minor portion of soda ash in the presence of an aluminum salt, capable of dissolving the gums and resins contained in the fibrous material, but of insufficient causticity to aifect the cellulose of the fibers, and maintaining the solution in a state .of mild agitation during said period.

5. The process of decorticating fibrous plants and individualizing the fibers thereof which comprises immersing the fiber-bearing portions of the plants, cut to desirable staple lengths, for a suitable period of time, in a heated aqueous, weak alkaline, solution comprising such major portions of tribasic sodium phosphate and minor portions of soda ash and aluminum sulphate, as will act to dissolve the gums and resins contained in the fibrous material, to precipitate tannic substances and to bleach the fibers without removing the waxes or oleaginous constituents of the fibers, but of insufficient causticity to afi'ect the cellulose of the fibers, introducing steam into the solution in such manner as to maintain the temperature thereof at substantially the boiling point and by ebulition to cause agitation of the solution, thereafter removing the foreign material that has been released,by the action of the solution, and thereafter washing and drying the fibers.

6. The process of decorticating and degumming fibrous plants which comprises immersing the fiber-bearing portions thereof, cut to desirable staple lengths, for a predetermined period of time, in a heated aqueous, weak alkaline, solution comprising the following chemicals in ap- 40 proximately the stated proportions:

Fresh water gallons 1000 Tribasic sodium phosphate pcunds 719 Soda ash do 62.5 Aluminum sulphate do- 7.8

maintaining the solution for said period of time at a temperature of approximately two hundred degrees F. to two hundred twenty-five degrees F., thereafter removing the material from said solution and washing the same to remove the fibrous plants which comprises immersing the fiber-bearing portions thereof, cut to desirable staple lengths, for a predetermined period of time, in a heated aqueous, weak alkaline, solution comprising the following chemicals in approximately the stated proportions:

Fresh water gallons 1000 Tribasic sodium phosphate pounds 719 Soda ash d0- 62.5 Finely divided aluminum do 23.3

maintaining the solution for said period of time at a temperature of approximately two hundred degrees F. to two hundred twenty-five degrees F., thereafter removing the material from said 0 solution and washing the same to remove the chemicals and the foreign materials which have been released by the action of the solution and subsequently drying the individualized fibers.

8. The process of decorticating and degumming ramieand individualizing and bleaching the fibers thereofwhich comprises immersing the fiberbearing portions of the ramie, cut to desirable .staple lengths, for a suitable period of time, in

an aqueous, weak alkaline, solution comprising major portions of tribasic sodium phosphate and minor portions of soda ash and aluminum sulphate, together with a small portion of sodium hypochlorite, acting to dissolve the gums and resins contained in the fibrous material, to precipitate tannic substances and to bleach the fibers without removing the waxes or oleaginous con- I stituents of the fibers, but of insufficient causticity to affect the cellulose of the fibers, introducing steam into the solution in such manner as to maintain the temperature thereof at substantially the boiling point and by ebulition to cause agitation of the solution, thereafter removing the foreign mat'erial that has been released by the action of the solution, subjecting the fibers to the action of a mild solution of sulphuric acid, and then washing and drying the fibers.

9. The process of producing cellulose pulp from woods containing gums and resins which comprises immersing chips thereof for a suitable period of time in a heated aqueous weak alkaline solution, comprising a major portion of tribasic sodium phosphate and a minor portion of soda ash in the presence of an aluminum-containing substance, capable of dissolving the "gums and resins contained therein, subsequently reducing the chips to pulp, and washing the pulp.

10. The process of producing alpha cellulose pulp from woods containing gums and resins which comprises immersing chips thereof for a suitable period of time in a heated aqueous weak alkaline solution, comprising a major portion of tribasic sodium phosphate and a minor portion of an aluminum sulphate, capable of dissolving the gums and resins contained therein, subsequently reducing the chips to pulp, washing the pulp, again treating the pulp in a like solution for a relatively short period of time, and finally thoroughly washing thepulp.

11. The process of producing "alpha cellulose pulp from woods containing gums and resins which comprises immersing chips thereof for a suitable period of time in a heated aqueous, weak alkaline, solution comprising the following chemicals in approximately the stated proportions:

Fresh water gallons 1000 Tribasic sodium phosphate pounds 700 to 750 Soda ash do 60 to Aluminum sulphate do 7 to 10 CERTIFICATE or CORRECTION.

Patent No. 2,073,682. March 15,1957.

FRANKLIN R. CHESLEY, JR.

It is hereby Certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 4,

first column, line 53, claim for "subseqnently" read subsequently;

line 64, claim '7, for --do---25.3" read -'---ounces--23.3; and that the said Letters Patent should be read with these corrections therein that the same may conform to. the record of the case in the Patent Office;

Signed and sealed this 25th day of May, A. D. 1937.

Henry Van Arsdale (Seal) v Acting Commissioner of Patents.

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