US1787880A - Bucking process for vegetable fibrous material - Google Patents

Description

Patented 1.... e, 1931' UNITED STATES. PATENT OFFICE e'usrav ULLHANN, or vrmm'a, aus'rara Became raocass r03. vacuum rn'motrs mar-am V I Drawing. Application filed January 2 4. 1980, Seriallo. 428,985, and in Austria January as, 1980.

Vegetable fibressuch as cotton, flax etc. are loaded with a large number of natural impurities, the removal of which is the object of the boiling or bucking process I which is frequently carried out for the fipuri-' mng fication of ve etable fibres in many re must be carried out in the After boiling there reon the fibre the natural rocesses an' leaching process. mains principally 1 colouring matter,

the well known way, usually by treatment with an oxidizing agent, such as chloride of lime, peroxides and the like. Y

The impurities to be removed by the boiling 5 or bucking process are of the most various kinds. Cotton, for example, principal representative of the vegetable fibres contains principally:

1. Fatty and waxy substances. 2 2. Pectin substances.

3. 'Albuminoids. 4. The natural colouring matters. 5. The woody and husk portions. The difierent behaviour of the impurities towards the'various reagents employed in bucking makes the bucking process very difficult to carry out. The impurities are soluble to a slight extent in water and to a greater extent in alkalies or alkali earths while the fats and waxes can only be removed from the fibre by saponification or by melting them out and emulsifying them. The fats and waxes, in particular, must be removed because they completely surround the fibres and preventthe access thereto of theother chemicals and solvents.

Scheurer has determined comparatively, in a long series of experiments the velocities of saponification when boiling with all kinds of chemicals, such as caustic and carbonated alkalies, alkali earths and other metallic salts and additions. Just as he gave precedence to Ca (OH) which is principally used in practice so, in the explanation of the present invention, the reactions which take place will be described with reference to lime compounds but this is not to be taken as meaning that the scope of the invention is so restricted accordingly. Scheurers investigations have shown, inter alia, that calcium hydroxide juts must be regarded as a particular advantage which is then removed in of boiling with lime is that the velocity of e not dependent in the same degree 0 th which is the n e effect an adequate urific'ation' of the fibrous material; 1t must a ways be followedby boilthereby is always better, more bluish?; the

both when used under ordinary pressure and when under superatmospheric pressure that 1s to say, at temperatures up to and h1gher,-efiects the most rapldsaponification of the fatty and waxy substances and carries it out in a much shorter time than comparatlvely high percentagesof caustic alkali or carbonated alkali. A circumstance which circulation does not play any im ortant part 1n the process, that is-to say, the chemical process of saponification and the removal of the fatty substances and other impurities is quantity of material treated at one time in a boiler as when boiling is carried out with solutions of caustic alkalies or soda.

Bolling with lime alone, however, can never ing with a caustic or a carbonated alkali. Ordinarily after being boiled withlime, the fibrous material is washed, acidified, washed again and then boiled with an alkali. The two boilings together are shorter, that is to say the take up less time than one boiling w th al ali alone. At the same time, boiling w1t h hme introduces other advantages. The white of the bleached material obtained thread is smoother, probably owing to the fact that in boiling with lime the lime paste envelopes and protects the threads or the fabric.

. Despite these im ortant' advantages boilmg with lime and a alies has been more and more displaced by boiling with alkalies alone and the chief reason for this being that the latter method can be carried out in a single operation, whereas after the lime boiling process carried out as above described, two

or if the acidification be included, three operation's are necessary. When boiling with alkalies various additions to the bucking liquors have been suggested and used in order to assist the emulsi cation of the impurities and the wetting of the fibrous material, but nothing further will be said of these added substances in this connection.- All these substances are, however, merely for the urpose of acceleratin the boiling with alka es and this not only or obvious economical reasons since rolonged boilin entails increased expense lbr steam and la our and lessons the 'eld of'the apparatus) but more particuarly, because s ort boiling brings with it the conservation of thefibrous material in an undamaggd state on which the atest value must placed. Nevertheless, oiling with alkalies a one has not secured the advantage as regards shortness of time and superior appearances of the material, which is obtaine when-the fibre is boiled 0th with lime and with alkalies.

. Simultaneous treatmentof the fibre with ime and alkali compounds has not hitherto been found possible, asthe lime soaps which are formed prevent the access of the caustic alkalitothe fibre, and carbonated alkalies could not be used owing to their precipitating action on lime water.

The present invention enables the high saponifying' action of calcium hydroxide to be utilized n the boilin of fibrous material and at the same time, t at is to say, in one sin 19 operation, it enables the lime soaps which are formed to be brought into solution or converted into a hi hly dispersed form, so that the can easily e rinsed oil from the fibre. T is idea can be carried out in various ways. One mode of carrying out the invention consists in boiling vegetable fibres either under increased pressure or at ordinar pressure with a li uor which contains, in a dition to a caustic a ali, metallic hydroxide which forms insoluble soa s, e. Ca(OH)2, Ba(OH) Sr(OH) 401-6., Fe (OH) or a salt of such metals and also a substance which passes into a soluble or a high dispersed compound with the metal. Such substances are the well known soluble oil preparations which are insensitive to lime and which are obtained by the sulphonation of i castor oil and other oils and subsequently boiling them with alkalies, also sulphonation products of unsaturated fatty acids and resins. Bodies may also be used which are of guite a different chemical nature and are used or avoiding inconveniences which would otherwise be caused by the presence in water carbons with alkyl side of metallic soaps and also as wetting agents for spun fibres. Thus, for instance, the sulphonic acids of polynuclear aromatic hydrochains and other substances the metallic compounds of which behave in a similar manner may be used.-

In this process lime soaps are formed very rapidly, even at low temperatures and with a limited lime acts much more energetically on the fatty acids and saponifies them more rapid- If only lime and ly than caustic alkalies or alkali carbonates.

an alkali were used the insoluble lime soaps would envelop the fibres circulation of the liquid, because the 1 the fibre and dissolveor emulsify the various impurities contained therein.' The process therefore renders it possible to work with lime and an alkali in a single bath without introducing the aforementioned. disadvantages and to do this in such away that each of the reagents is able to develop to the full its best possible solvent, saponifying or emulsifying action.

As the process according to this invention permits of carrying out the bucking rocess in a highly accelerated form and e ects a more thorough purification under ordinary pressure than heretofore, it is particularly suitable also for bleaching coloured textiles and continuous bleaching, which is most-1y carried out as piece lea ching. For bleaching coloured textiles 5hr present process has the advantage that the fibres are conservated in a better manner by the shortening of the time of boiling and by the avoidance of increased pressure, although a more thorough purification takes place than in the bleaching processes for coloured textiles hitherto employed.

In continuous bleaching on the basis of the present process considerable simplificationof the apparatus is secured as the work does not have to be carried out under pressure. As is Well known the means for continuous bleaching under high pressure are so complicated and difiicult to supervise and their work so difficult to control that it has not hitherto been possible, in practice, to introduce this method of working, which would otherwise be very advantageous, while bleaching in open vessels on the continuous process has hitherto not yield any satisfactory results.

Another mode of carrying out this invention consists in introducing into the boiling liquor, in addition to a caustic alkali, a metallic compound of those oil preparations or other emulsifying agents which are capable invention also extends to the production of the reagents required to carry out this process, that is to say, to the production of metalic compounds of oil preparations, sulphonic acids of polynuclear aromatic hydrocarbons with alkyl side chains and the like, all of which bodies behave in the above mentioned manner towards metallic soaps.

. The basis of the process described is, doubtf less, the saponifying action of, the lime, but it is of no co uence if this be present in a quantity. below t e stoichiometric in proportion to the particular fats and waxes contained in the fibre, because the caustic alkali and the other substances added have also a sa nifying and emulsifying action. As a ru e, however, the work is carriedout in first instance for reasons of economy with an excess of lime over the approximate actual consumption thereof whic latter can be estimated, as the amount of fat and wax contained in cottons of various origins (e. g. East Indian, Egyptian, American and others) is known from the outset just as in the other fibrous materials.

Examples 1. In a boiler containing 2000 kg. of cotton material to be boiled out and about 8000 litres of. bucking liquor there are used for the boiling out process.

500 g. calcium oxide (CaO) in the form of lime water.

g5 kg. solid caustic soda (NaOI-I) 6 kg. of a sulphonated oil containing 60 per cent of fatty acids and insensitive to lime.

After boiling has been carried out for about 4 hours at 100 C. without pressure or after so about 2% hours boiling at a pressure of 2 atm.

only,

above atmospheric pressure, the bucking process is complete. The charge is then washed, acidified if necessary washed again and the material, which has also become con- 85 siderably lighter in colour is treated in the usual way with quite dilute chloride of lime solutions or peroxides and the like and the bleaching process terminated in the usual way. Or the material, which is to be boiled may after being boiled, washed and acidified, and then washed once more and dried. A very thorough preliminary bleaching is thus obtained, which frequently makes a further white bleaching quite unnecessary,

e. g. for light shades of colour.

2. The material and the liquor are selected as in Example 1. Boilingis carried out with 80 kg. calcium oxide (CaO) and 12 kg. iso-' propylnaphthylamine sulphonate of sodium so or a substance of similar composition and act-.

ing in a similar manner. The material is then washed with water, acidified, preferably with hydrochloric acid, washed "again and then bleached.

3. Material and the li uor asin le 1. 380 g. of calcium oxi e (0:10), 40 f -solid causticsoda and 4600 g. of an oilcontaining per cent of fatty acid and insensi-- tive to lime are taken. The subsequent treat- 6.1 mentis as in Example 1.

4. Material and liquor as in Example 1. 35 kg. of solid caustic soda and the barium cpmpound of the dispersing agentare added.

The latter is produced as follows:

1300 g. of barium hydroxide are stirred ing 60 per cent of fatty acid are mixed gradterial.

washed out of the fibres.

with the .corres nding quantity of water and slowly mixe with a solution of 8800 g. of isopropylnaphthylamine sulphonic acid while stirring continuously.

Instead of the barium sa t of the said aromatic sulphonic acid the calcium salt of sul phonated unsaturated fatty acids may, for example, be taken. This is prepared as follows:'

47 50 g. of sulphonated castor oil containually, whilst being stirred, with a milk of lime prepared from 460 g. of commercial burned lime. The product obtained is concentrated and used in the form of a slip or slur W at I claim is 1. In a bucking process for vegetable fibrous materialsthe method consisting .in boiling the fibrous material to be treated in a liquor containing caustic alkalies, metallic hydroxides and substances adapted to cause the compounds produced from the natural fats and waxes of the fibrous material during boiling to assumea form in which such compound can easily be washed from the said material.

2. In a bucking process for vegetable fibrous materials, the method consisting in boiling the fibrous material to be treated in a liquor containing caustic alkalies, metallic hydroxides and substances adapted to convert the insoluble compounds which would normally be formed with the natural fats and waxes of the fibrous material into a form such that substantially all the impurities disengaged from the material during boiling can be washed out of the fibres of said ma- 3. In a bucking process for vegetable fibrous material, the method of treating the material simultaneously and in one single operation with caustic alkalies and metallic hydroxides consisting in adding tothe bucking liquor, metal compounds soaps that can easily be 4. In a bucking process for vegetable fibrous material, the method of treating the material simultaneously and in one single operation with caustic alkalies and metallic hydroxides, consisting in adding to the bucking liquorv a third reagent which prevents the envelopment of the fibres in obstructive metallic soaps and ensures that the final form of the compounds produced with the natural fats and waxes of the fibre during boiling shall be such that substantially all the impurities can be removed from the fibre by simple washing operations.

5. In a bucking process for vegetable fibrous materials the method consisting in boiling the fibrous material to be treated with a liquor containing a caustic alkali and a substances which form with the I metallic salt of a; substance adapted to bring the metallic soaps of the fats and waxes in 'the'fibrous material to a state such that the residual matter remaining in the fibre after 3 boiling can be removed bf simple washing.

In testimony whereof aflix my signature.

GUSTAV 'U'LLMANN.