US1997153A - Manufacture of alpha cellulose - Google Patents

Manufacture of alpha cellulose Download PDF

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Publication number
US1997153A
US1997153A US712628A US71262834A US1997153A US 1997153 A US1997153 A US 1997153A US 712628 A US712628 A US 712628A US 71262834 A US71262834 A US 71262834A US 1997153 A US1997153 A US 1997153A
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pulp
cellulose
lye
autoclave
water
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US712628A
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Pou Jose Sala
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    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C5/00—Other processes for obtaining cellulose, e.g. cooking cotton linters ; Processes characterised by the choice of cellulose-containing starting materials

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  • Patented A r. s, 1935 PA-TENT ol-F cE MANUFACTURE OF ALPHA CELLULOSE,
  • the present invention relates to the manufacture of alpha cellulose, andmore particularly to 5 a process for manufacturing this product from bamboo canes in a form suitable for the production of cellulose esters as substitutes for cotton pulp and its derivatives. 7
  • theidea has been conceived to use in place of a continuousprocess, a fractional process which at a first boiling at a presv sure of 0.5 atmosphere in an alkaline lye containing 1.5 per cent of the corresponding alkali, in the proportion of 1 :5 between the weight of the material treated and the weight of the bath, elim- February23, 1934, Serial No. 712,628 In-Spain October 21, .1933
  • the alkaline hydrates even at the low temperal tures at which the operation is carried out, always exert a hydrolyzing effect on the hemi-celluloses which accompany the alpha cellulose, and the oxidizing molecules of-the hydrates always exercise some hydrolytic action' also on the alpha i celluloses. For that reason it has been considered advisable to introducein the first stage a reducing element such as-an alkaline sulphite or sulphites, which combining with-oxygen, prevents the said hydrolyzing effect andleaves the elimi- 2 nation of the lignine and of the semi-celluloses to the second stage of the process, so that the first stage thereof serves only for the elimination of the above-mentioned substances.
  • a reducing element such as-an alkaline sulphite or sulphites
  • the first object aimed at by the use of this lye is to avoid theeifects of hydrolyzation which have been provided for in the first stage.
  • Sodiumsulphide and sulphite are intended to attain this 4 object.
  • the lye in the form of sodium sulphide and caustic soda could also be-combined in any proportion which may be con- 'sidered suitable for combining the said products with the lignine. 4
  • the highly beneficial reducing effect of the sodium sulphide for obtaining super-alphas may be assumed'to' be represented by the following equation:
  • the acid contents of the lignine or the lignitic acids are neutralized by the alkaline hydrate or by the hydrolysis of the NazS to NaOH, giving soluble soda compounds.
  • the NaHS combines with alcohols (to form mercaptans) and with phenols, the result of the reaction being by weight, with regard to the sulphide, as follows:
  • the temperatures applied for the elimination of the lignine start at 140 degrees C., but in some kinds of old bamboos, that is to say, bamboos which arein the advanced period of lignification, or inthe bamboos which grow in shallow soils which prevent the roots of the plant from penetrating deeply into the earth and where the rainy periods are veryrare or the'rain is scarce between the stage of first growth of the stem and the stage of second growth in which latter the branches and the leaves appear, asa result of ,which there is a lack of moisture in the roots and therefore in the plant, with the consequent quick drying up of the starches in the fundamental porenchyma of the plant, on the said alimentary substances being eliminated for the normal development of the cellulose until its maximum uniform growth is reached, there takes place a premature ageing, so
  • guayacol that is to say monomethyl ether of the phenol which is found in cellulose.
  • the guayacol quickly dissolves the coating of lignine gelatinized by the hydrate and allows new portions of the lye to attack rapidly new zones of lignine. Owing to the action of the guayacol it is possible, even in cases where old.
  • bamboos or bamboos'grown in bad conditions are used, to do without varying the times and the pressures required for the operation, and in these pressure of 8 atmospheres.
  • a. further washing operation with hot water is carried out.
  • the first water is emulsified with a benzol in the proportion to the quantity of the guayacol used, plus 50% by weight of this body.
  • the product is washed two or three times with cold water, and thereupon bleached with a hypochlorite solution of one half to one degree B.
  • This cellulose thus obtained is washed and submitted to the action of a HFl bath of half percent. In this way the remains of the silica are eliminated, and the residue of ashes can be reduced to 0.3%.
  • the product is washed in plenty of water, and the bleached cellulose is subjected to the action of a solution of bisulphite of soda of 2 B. at a temperature which may vary between 60 degrees C. at atmospheric pressure and '120 degrees C. at a pressure of one atmosphere.
  • This operation eliminates the quantities of oxiand hydrocellulose, and the rest of the lignine that may still be left.
  • the cellulose is washed in plenty of water and may be submitted if desired to the action of'a solution of peroxide of sodium or of peroxide of hydrogen for the purpose of improving its whiteness.
  • the cellulose obtained by this process from the bamboos has exceptional characteristics which are in no way inferior to the characteristics of cotton.
  • cut bamboos afterhaving been left to dry in the field for a period of forty days are exposed to the action of running water, either in a river or in suitable pools for a period of time which varies from 7 to 15 days.
  • the bamboos prepared in this way are introduced into a grinding mill l constituted by four pairs of cylinders or rollers, two of which are provided with grooves or flutes, and these two rollers owing to the action of hydraulic pressure applied to them, flatten and break the joints or knots of the bamboos.
  • the other two pairs of rollers are provided with teeth arranged in zigzag shape and are also subjected to strong by draulic pressure, their object being to cut the bamboos.
  • This operation is of the greatest importance, inasmuch as, the uniformity of the boiling depends on the elimination of the air from the perforated vessels, since the said air may cause the mass to fioatin the boiling lye, which would retard by at least one hour the time of immersion.
  • the bamboo stems having been cut to portions of about one square centimetre section and completely disintegrated, drop into a pit which is 10- cated in front of buckets 2 which lift the cut stems up to the hopper 3.
  • the said hopper is so dimensioned that its capacity is the same as that of the autoclave 4 with which it is associated.
  • the said autoclave receives the new lye which is supplied from 18, and which has been mixed in a well ill provided with an agitator, with the regenerated iyes coming from the tank 26.
  • This first stage of boiling of the bamboo being finished, the lye by means of which the second operation or stage is carried out, is introduced into the autoclave, the same precautions being taken with regard to the air as were adopted in the previous operation, and a continuous circulation being kept up during theboiling operationby means of the pump already referred to.
  • the lye is returned to the well 5 from which it passes together with the first two washing waters, to a tank 2
  • are conveyed to a. multiple action evaporator 22 which is fed with the steam coming from the steam generator 20 andv afterwards pass to the rotary oven 23 in which they are calcined and from the latter pass to thekpit 24 from which an Archimedean screw raises them to the caustifying vessels 25. from which they pass to settling tanks 26.
  • the cellulose is returned to the well 5 in which it is diluted with water and washed therewith, being stirred for the purpose by a powerful agitating device.
  • the pulp which is thus formed is conveyed by means of a pump to a thickener or concentrator 6 which in its turn after having eliminated the water, delivers the pulp to a disintegrator-deflbrator of the kind known under the name of cone breaker.
  • This disintegrator is sufiicient for the purpose in asmuch as the material to be treated is thoroughly boiled pulp which does not normally contain any knots (since it has been ground in the mill I); but in cases in which, owing to some defect in the grinding mill, the knots of the bamboos had not already been sufliciently ground, it would be necessary to interpose between the well 5 and the concentrator 6, one or more rotary purifiers working with one millimetre pitch.
  • the pulp On being discharged from the cone breaker, the pulp is introduced into one or more washing and bleaching vats or machines 8 to which is supplied a solution of sodium hypochlorites supplied from decanting devices 30. From the said washing and bleaching machine or machines 8 the cellulose passes to a vat 9 where it is treated with hydrofluoric acid of the above-mentioned concentration.
  • This vat is lined inside with a plastic material having for its basis rubber, in order to render it proof against the action of the acid which comes from a supply unit 29.
  • the cellulose passes from the vat I to a vat III in which it is washed with plenty of water until the last traces of the acid are removed and from the said vat the cellulose passes to a concentrator II from which it is here conveyed by a pump into an autoclave l2.
  • the cellulose is introduced into the autoclave l2 through the bottom part of the latterand is forced to circulate through several inclined planes arranged in the interior of the said autoclave, arid at the proper time the corresponding solution of sodium sulphlte is introduced.
  • the bath is thereupon heated by means of steam coming from the steam generator 20 and passing through a closed coil arranged at the bottom of the apparatus. In these conditions, the pressure rises to one atmosphere, and the pulp is extracted from the upper part of the autoclave by a pump provided with a special pressure-relief device. On its discharge from the said pump, the pulp passes into a vat I3 in which it is thoroughly washed.
  • the sulphlte used in the last named lye is supplied from a unit 21.
  • the pulp thus obtained which contains from 97 to 98% of alpha cellulose is of a beautiful white colour, and its fibres are 7 to 8 millimetres long.
  • This super-alpha cellulose with such exceptional characteristics, extracted from bamboos, is obtained in a proportion of 35 to 40% of the dry 'plant and is more particularly suitable for the esterification as well as for the manufacture of papers, particularly of papers for documents, ledgers and bank notes.
  • this fibre can be used in place of cotton for the hygienic and sanitary purposes for which the latter is employed.
  • the product obtained by the process hereinbefore described has the following characteristics:
  • Viscosity equal to that of pure normal cotton in a cupro-ammoniacal solution of 0.5%
  • a process for the manufacture of alpha cellulose from bamboos comprising in steps: drying out bamboo in the open air; exposing the cut and dried bamboo to the action of running water; grinding said bamboo to form a kind of tow; boiling said tow in an autoclave with a lye composed of alkaline hydrates and a reducing agent at a pressure of .5 to 1 atmosphere; washing said tow in the autoclave first'with hot water and then with cold water; subjecting the bamboo pulp thus produced in the same autoclave to the action of a second lye containing alkaline hydrate, sodium sulphide, sodium sulphite and guayacol for one hour at 156 C. and 4.8 atmospheres pressure, and for a few hours at 143 C.
  • a process for the manufacture of alpha cellulose from bamboos comprising in steps: drying cut bambooin the open air; exposing the cut and dried bamboo to the action of running water; grinding said bamboo to form a kind of tow; boiling said tow in an autoclave with a lye composed of alkaline hydrates and a reducing agent at a pressure of -.5 to 1 atmosphere; washing said tow in the autoclave first with hot water and then with cold water; subjecting the bamboo pulp thus produced in the same autoclave to the action of a second lye containing alkaline hydrate, sodium sulphide, sodium sulphite and guayacol for one hour at 156 C.
  • a process for the manufacture of alpha cellulose from bamboos, in a form suitable for conversion to cellulose esters as substitutes for catton pulps and derivatives comprising in steps: drying the cut bamboo in the field in the open air for forty days; exposing the-cut and dried bamboo to the action of running water in a river for from"?

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  • Polysaccharides And Polysaccharide Derivatives (AREA)
US712628A 1933-10-21 1934-02-23 Manufacture of alpha cellulose Expired - Lifetime US1997153A (en)

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ES430259X 1933-10-21

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FR (1) FR763906A (fr)
GB (1) GB430259A (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2666173A (en) * 1948-12-16 1954-01-12 Firestone Tire & Rubber Co Electric motor positioned according to time-temperature schedule
WO2010144969A1 (fr) * 2009-06-19 2010-12-23 Eze Board Australia Pty Ltd Production de perlite et carton pour panneaux composite à base de fibres
US7866622B2 (en) 2007-01-05 2011-01-11 Milestone Av Technologies Llc In-wall mount
CN102677495A (zh) * 2012-05-29 2012-09-19 宜宾长毅浆粕有限责任公司 一种适用于漂白竹纸浆改性制备溶解浆的备料工艺

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2666173A (en) * 1948-12-16 1954-01-12 Firestone Tire & Rubber Co Electric motor positioned according to time-temperature schedule
US7866622B2 (en) 2007-01-05 2011-01-11 Milestone Av Technologies Llc In-wall mount
WO2010144969A1 (fr) * 2009-06-19 2010-12-23 Eze Board Australia Pty Ltd Production de perlite et carton pour panneaux composite à base de fibres
CN102677495A (zh) * 2012-05-29 2012-09-19 宜宾长毅浆粕有限责任公司 一种适用于漂白竹纸浆改性制备溶解浆的备料工艺
CN102677495B (zh) * 2012-05-29 2015-07-01 宜宾丝丽雅集团有限公司 一种适用于漂白竹纸浆改性制备溶解浆的备料工艺

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Publication number Publication date
FR763906A (fr) 1934-05-09
GB430259A (en) 1935-06-17

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