US2368527A - Treatment of cellulosic pulp - Google Patents

Treatment of cellulosic pulp Download PDF

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US2368527A
US2368527A US45788942A US2368527A US 2368527 A US2368527 A US 2368527A US 45788942 A US45788942 A US 45788942A US 2368527 A US2368527 A US 2368527A
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cellulose
peroxide
pulp
solution
hydrogen
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Sidney M Edelstein
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Sidney M Edelstein
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    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08BPOLYSACCHARIDES; DERIVATIVES THEREOF
    • C08B1/00Preparatory treatment of cellulose for making derivatives thereof, e.g. pre-treatment, pre-soaking, activation

Description

S Fl

Patented Jan. 30, 1945 j Cross Reference No Drawing.

' '7 Claims.

Thisinvention. relates to treated. cellulosic pulp and the method of treatment. Moreparticularly the invention. relates t the. making; of a. wood pulpv of reduced and stabilized. viscosity by treatment with hydrogen peroxide in; proportion. that is very small in relation to the' amount of pulp I treated and in conjunction with a metal. of kind to be described.

The use of hydrogen peroxide to lower the viscosity of wood pulp has been known heretofore. It has been necessary, however, to use relatively large proportions of the peroxide.

I have now discovered that at least equal reduction in viscosity and better control of the oporation may be effected by the use of much. smaller proportions of peroxide than heretofore necessary provided the treatment with peroxide is. made in the presence of iron, copper, aluminum, manganese, or like metal. v

The invention comprises the. method of treatment of pulp with the limited proportion of peroxide and the metal and. also the resultingproduct. In the preferred embodiment, the invention comprises such treatment of pulp that has been previously reduced to a substantially pulverulent condition, effecting the treatment at a pH of'approximately 6 to Band using the hydrogen peroxide on the anhydrous basis in proportion not substantially greater than 1% of the weight of the pulp and at a temperature between about 130 and. the boiling point of'the aqueous solution of the peroxide at the prevailin pressure, preferably between about 180 and212 F. To avoid continuance of'the reaction and objectionable uncontrolled Variations of viscosity as the product stands, remaining peroxide is re moved, as by centrifuging and rinsing, after the viscosity is lowered'to the desired level.

Proceeding as described there is obtained the desired reduction inviscosity of the cellulose without'other objectionable change. Thus the viscosity of alpha cellulose may be lowered to a tenth or less of the original, as from about 6,000 to 700 or even 100'or 200 centipoises as measured by test in sodium 'zincate solution. In this test there is formed a solution of the cellulose in standard concentration in a standard (10%) solution of sodium zincate and. the viscosity is determined by the Stormer or an improved form of such viscosimeter.

The cellulose that has been so reduced in vis cosity is suitable for use in making commercial solutions of cellulose in sodium zincate for applicatlon to textiles or thelike and subsequent precipitation of a cellulose coating by the addi- Application September 10, 1942;" Serial No. 457,889

tionof. sulfuric acid: in amount to neutralize the alkalinity ofthezincate solution. The treated pulp may also-be used to makev cellulose xanthate solutions. for the manufacture of: rayon or cellulose sheeting when low viscosity cellulose is desired. Also, the treated pulp is suitablefor nitration. in making pyroxylin for lacquer solutions.

As the cellulose used, there is employed wood pulp, cotton linters, rayonwaste. or other pulp. that is largely or practically entirely cellulose. Wood pulp and cotton are the preferred materials because of their relatively low cost and suitability. If wood pulpisused, the kind chosen is preferably a. purified grade: known as alpha cellulose. Thevcotton used is suitably that which.

has been purified by alkali digestion, to. remove undesired ingredients.

In any case, the cellulose tobe used: should. be in a state of fine subdivision and preferably substantially pulverulent so thatit is reacted upon readily andsubstantially uniformly by the peroxide treating solution. A. spun. thread, for ex.- ample, is not satisfactory. Neither. is a: fabric. While av usual loose. pulp. may beusedunder some circumstances, the cellulose. for best results must be finely divided. I

Such a. substantially pulverulent. cellulose is made by grinding or preferably cutting the se lected cellulose to such. fineness that it will pass largely through a 30-mesh. screen or preferably through a BO-mesh screen. Actually I prefer to use cellulose which is, predominantly IOU-mesh or finer, difficulty having. been found with material of the coarser meshes from lumping of the cellulose in the treating solution.

Thefmoisture content during the comminuting of the cellulose may be that which is normally present in the air-dried material. ,When the moisture content is much higher, the cellulose may be made into a slurry and ground in a ball mill.

The viscosity reducing combination is hydrogen peroxide in contact with iron; copper; aluminum, or manganese; iron being particularly effective and constituting the preferred metal particularly when in the form of stainless steel. Stainless steel as the container for the. reaction mixture is very satisfactory commercially inproviding an adequate supply ofiron and avoidin such an excess as might cause i ron' discoloration of the product.

The metal may be in. massive form, as, for, example, in the form of the container in which the reaction mixture is held or as a few added nails, or inthe formof small pieces or line powder pro- Search Room vided there are no objections to the difficulty experienced in separating small pieces from the product or to some discoloration from the use of such pieces. In other words, the metal is present in elemental form.

The metal accelerates the reaction and makes unnecessary a large pro-portion of peroxide.

As the peroxide, only hydrogen peroxide is satisfactory. I I

The concentration of the peroxide solution which contacts the cellulose is very limited. There is thus provided better control of the reaction which, in the presence of the metal, is satisfactory in speed even at the low concentration of the peroxide. If a long time is to be allowed for the reaction, say a day or so, the concentration of the peroxide in the treating solution may be as low as 0.001%. Ordinarily there is used an aqueous solution of 0.001 to 0.1% concentration of hydrogen peroxide, all proportions of peroxide being given herein on the anhydrous basis unless specifically stated otherwise. Stronger solutions are not required or justified on the basis of cost. Ordinarily I use a solution of hydrogen peroxide of concentration about 0.003 to 0.03%.

It will be understood that the rest of the solution is ordinarily water and the concentrations given are the concentrations of hydrogen peroxide in the water solution which bathes the cellulose at the beginning of the treatment described.

It is very important to control the total amount of peroxide used in proportion to the cellulose being treated. Thus, it is necessary to use approximately 0.1 to 1 part of actual hydrogen peroxide for 100 parts of the cellulose Ordinarily I start with a commercial 30% solution of hydrogen peroxide containing the conventional proportion of acid or other stabilizer for the hydrogen peroxide and add this to sufiicient water at a temperature of around 210 F. to lower the proportion of peroxide to'one of the concentrations given above. So much of the original 30% hydrogen peroxide is used as required to give about 0.1 to 1 part for 100 parts of the cellulose and to wet all the cellulose thoroughly. This amount is usually about 5 to parts for each part of the cellulose. The cellulose is then introduced rapidly and vigorously stirred into the solution. The

' v solution is heated approximately to the boiling point. The pH is established at 6 to 8. The cellulose, being added at ordinary temperatures, lowers somewhat the temperature, say to 180 F. or so, and the mixture is stirred at about this temperature for about an hour or two. The peroxide is then separated, as by centrifuging, so that the peroxide is removed from the remaining treated cellulose. Preferably the material is rinsed with cold water in the centrifuge till substantially free from peroxide, so that further uncontrolled reaction is avoided.

If the pH of the mixtur as first made and before the warming to lower the viscosity of the cellulose is not within the range of approximately 6 to 8, a usual acid, alkali, or buffer as may be required is added to adjust the pH to that range. For a pH on either side of that range, there is a decreased rate of reaction of the hydrogen peroxide and metal combination in lowering the visccsity of the cellulose.

Example 1 Nine gallons of water are warmed to 210 F. in a stainless steel container provided with an agitator. One pound of commercial 30% hydrogen peroxide is added to the liquid. Then 100 pounds of 92% alpha cellulose pulp which has been previously cut to 100-mesh fineness are added at one time. The mixture is agitated for about one .hour, during which time the mixture slowly cools.

The cellulose slurry is then discharged to a centrifuge and the cellulose is freed of the liquor as far as possible and finally washed with warm water. The pulp is then dried in an air drier or is used in the wet state for making solutions.

The initial viscosity of the cellulose before this treatment would be about 6,000 centipoises by, the standard method described and after treatment about 1,000 centipoises.

Example 2 One hundred. pounds of pulp as described in Example 1 are added to 100 gallons of water at F. containing 3 pounds commercial (30%) hydrogen peroxide. This mixture is agitated for 24. hours in a wooden tank into which small pieces of iron have been introduced. After 24 hours the cellulose is separated from most of the remaining liquor in a filter press and thoroughly washed with warm water.

The viscosity change due to this treatment will be of the same order as in Example 1.

Example 3 The procedure of Example 1 to 2 is followed except that the prevailing pressure on the mixture is made superatmospheric, say 10 to 40 pounds gage, and the batch is heated to approximately the boiling point of the peroxide solution in an autoclave.

Example 4 The treated cellulose from any of the above treatments is substituted pound for pound in making cellulose zincate solutions in accordance with the description given in U. S. Patent No. 2,322,427, issued June 22, 1943, on an application filed August 19, 1941, for Cellulose product.

It will be understood that it is intended to cover all changes and modifications of the exthe boiling point of the aqueous solution under i the prevailing pressure until the viscosity is reduced to the desired level, separating remaining hydrogen peroxide from the treated pulp, and then drying the product, the cellulosic pulp being of such fineness before treatment with the peroxide that the pulp will pass largely through a 30 mesh screen.

2. In making a cellulosic pulp of lowered viscosity, the method which comprises forming a mixture of wood pulp, of such fineness as to pass in predominating proportion through a 60 mesh screen, with a dilute aqueous solution of hydrogen peroxide at a pH of about 6 to 8 and warming the mixture in contact with a metal in elemental form selected from the group consisting of iron,

'6. ULtnbmnu a Dir-mu; 1w:

copper, aluminum, and manganese to effect the desired lowering of viscosity.

3. Th method described in claim 2 the proportion of the hydrogen peroxide being not substantially in excess of 1 part on the anhydrous basis to 100 parts of the cellulosic pulp.

4. The method described in claim 2, the wood pulp before mixing with the hydrogen peroxide solution being previously reduced to substantially pulverulent condition causing the pulp to be so fine as to pass in predominating proportion through a 60 mesh screen and the aqueous solution of the peroxide being used in amount to wet thoroughly all of the cut wood pulp before the warming is undertaken;

5. The method described in claim 1, the metal used being iron.

tress tteierance tions recited in claim 1, the said pulp being a powder of fineness to pass in predominating proportion through a 60 mesh screen and of such low viscosity that when dissolved in aqueous sodium zincate solution in the proportion of 5 parts of the pulp to. 100 parts of the zincate solution, the

viscosity of the resulting solution at. 25 C. is 100 1 to 1500 centipoises.

SENEY M. EDELSTEIN.

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US2368527A 1942-09-10 1942-09-10 Treatment of cellulosic pulp Expired - Lifetime US2368527A (en)

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Cited By (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2444022A (en) * 1941-06-27 1948-06-29 American Enka Corp Process of making a solution of cellulose
US2520963A (en) * 1947-06-06 1950-09-05 Richard E Reeves Production of improved cellulosic materials
US2542285A (en) * 1946-07-23 1951-02-20 Rayonier Inc Cellulose products
US2555446A (en) * 1947-06-06 1951-06-05 Phillips Petroleum Co Production of carboxyalkyl cellulose ethers
US4022965A (en) * 1975-01-13 1977-05-10 Crown Zellerbach Corporation Process for producing reactive, homogeneous, self-bondable lignocellulose fibers
US4314854A (en) * 1980-03-10 1982-02-09 Bio Research Center Company Ltd. Method for the treatment of cellulosic substances with hydrogen peroxide
US4410397A (en) * 1978-04-07 1983-10-18 International Paper Company Delignification and bleaching process and solution for lignocellulosic pulp with peroxide in the presence of metal additives
US20060240110A1 (en) * 2005-03-31 2006-10-26 Kiick Kristi L Multifunctional and biologically active matrices from multicomponent polymeric solutions
US20060260773A1 (en) * 2005-05-02 2006-11-23 Zheng Tan Ligno cellulosic materials and the products made therefrom
US20060289132A1 (en) * 2005-06-28 2006-12-28 Akzo Nobel N.V. Method of preparing microfibrillar polysaccharide
WO2007001229A1 (en) * 2005-06-28 2007-01-04 Akzo Nobel N.V. Method of preparing microfibrillar polysaccharide
US20070119556A1 (en) * 2003-09-23 2007-05-31 Zheng Tan Chemical activation and refining of southern pine kraft fibers
US8778136B2 (en) 2009-05-28 2014-07-15 Gp Cellulose Gmbh Modified cellulose from chemical kraft fiber and methods of making and using the same
US9512563B2 (en) 2009-05-28 2016-12-06 Gp Cellulose Gmbh Surface treated modified cellulose from chemical kraft fiber and methods of making and using same
US9512237B2 (en) 2009-05-28 2016-12-06 Gp Cellulose Gmbh Method for inhibiting the growth of microbes with a modified cellulose fiber
US9511167B2 (en) 2009-05-28 2016-12-06 Gp Cellulose Gmbh Modified cellulose from chemical kraft fiber and methods of making and using the same
US9617686B2 (en) 2012-04-18 2017-04-11 Gp Cellulose Gmbh Use of surfactant to treat pulp and improve the incorporation of kraft pulp into fiber for the production of viscose and other secondary fiber products
US9719208B2 (en) 2011-05-23 2017-08-01 Gp Cellulose Gmbh Low viscosity kraft fiber having reduced yellowing properties and methods of making and using the same
WO2017220777A1 (en) * 2016-06-23 2017-12-28 Cellucomp Limited Method for preparing cellulose-containing particles
US9951470B2 (en) 2013-03-15 2018-04-24 Gp Cellulose Gmbh Low viscosity kraft fiber having an enhanced carboxyl content and methods of making and using the same

Cited By (37)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2444022A (en) * 1941-06-27 1948-06-29 American Enka Corp Process of making a solution of cellulose
US2542285A (en) * 1946-07-23 1951-02-20 Rayonier Inc Cellulose products
US2555446A (en) * 1947-06-06 1951-06-05 Phillips Petroleum Co Production of carboxyalkyl cellulose ethers
US2520963A (en) * 1947-06-06 1950-09-05 Richard E Reeves Production of improved cellulosic materials
US4022965A (en) * 1975-01-13 1977-05-10 Crown Zellerbach Corporation Process for producing reactive, homogeneous, self-bondable lignocellulose fibers
US4410397A (en) * 1978-04-07 1983-10-18 International Paper Company Delignification and bleaching process and solution for lignocellulosic pulp with peroxide in the presence of metal additives
US4314854A (en) * 1980-03-10 1982-02-09 Bio Research Center Company Ltd. Method for the treatment of cellulosic substances with hydrogen peroxide
US20070119556A1 (en) * 2003-09-23 2007-05-31 Zheng Tan Chemical activation and refining of southern pine kraft fibers
US20090054863A1 (en) * 2003-09-23 2009-02-26 Zheng Tan Chemical activation and refining of southern pine kraft fibers
US8262850B2 (en) 2003-09-23 2012-09-11 International Paper Company Chemical activation and refining of southern pine kraft fibers
US20060240110A1 (en) * 2005-03-31 2006-10-26 Kiick Kristi L Multifunctional and biologically active matrices from multicomponent polymeric solutions
US8753484B2 (en) 2005-05-02 2014-06-17 International Paper Company Ligno cellulosic materials and the products made therefrom
US20170172152A1 (en) * 2005-05-02 2017-06-22 International Paper Company Ligno cellulosic materials and the products made therefrom
US8282774B2 (en) 2005-05-02 2012-10-09 International Paper Company Ligno cellulosic materials and the products made therefrom
US20060260773A1 (en) * 2005-05-02 2006-11-23 Zheng Tan Ligno cellulosic materials and the products made therefrom
US8007635B2 (en) * 2005-05-02 2011-08-30 International Paper Company Lignocellulosic materials and the products made therefrom
US20100112351A1 (en) * 2005-06-28 2010-05-06 Akzo Nobel N.V. Method for preparing microfibrillar polysaccharide
JP4707743B2 (en) * 2005-06-28 2011-06-22 アクゾ ノーベル ナムローゼ フェンノートシャップAkzo Nobel N.V. Process for the preparation of microfibrillar polysaccharide
US7700764B2 (en) * 2005-06-28 2010-04-20 Akzo Nobel N.V. Method of preparing microfibrillar polysaccharide
KR100942753B1 (en) 2005-06-28 2010-02-18 아크조 노벨 엔.브이. Method of preparing microfibrillar polysaccharide
JP2008544112A (en) * 2005-06-28 2008-12-04 アクゾ ノーベル エヌ.ブイ. Process for the preparation of microfibrillar polysaccharide
WO2007001229A1 (en) * 2005-06-28 2007-01-04 Akzo Nobel N.V. Method of preparing microfibrillar polysaccharide
US20060289132A1 (en) * 2005-06-28 2006-12-28 Akzo Nobel N.V. Method of preparing microfibrillar polysaccharide
US9777432B2 (en) 2009-05-28 2017-10-03 Gp Cellulose Gmbh Modified cellulose from chemical kraft fiber and methods of making and using the same
US9512562B2 (en) 2009-05-28 2016-12-06 Gp Cellulose Gmbh Modified cellulose from chemical kraft fiber and methods of making and using the same
US9512563B2 (en) 2009-05-28 2016-12-06 Gp Cellulose Gmbh Surface treated modified cellulose from chemical kraft fiber and methods of making and using same
US9512561B2 (en) 2009-05-28 2016-12-06 Gp Cellulose Gmbh Modified cellulose from chemical kraft fiber and methods of making and using the same
US9511167B2 (en) 2009-05-28 2016-12-06 Gp Cellulose Gmbh Modified cellulose from chemical kraft fiber and methods of making and using the same
US9926666B2 (en) 2009-05-28 2018-03-27 Gp Cellulose Gmbh Modified cellulose from chemical kraft fiber and methods of making and using the same
US8778136B2 (en) 2009-05-28 2014-07-15 Gp Cellulose Gmbh Modified cellulose from chemical kraft fiber and methods of making and using the same
US9909257B2 (en) 2009-05-28 2018-03-06 Gp Cellulose Gmbh Modified cellulose from chemical kraft fiber and methods of making and using the same
US9512237B2 (en) 2009-05-28 2016-12-06 Gp Cellulose Gmbh Method for inhibiting the growth of microbes with a modified cellulose fiber
US9970158B2 (en) 2009-05-28 2018-05-15 Gp Cellulose Gmbh Modified cellulose from chemical kraft fiber and methods of making and using the same
US9719208B2 (en) 2011-05-23 2017-08-01 Gp Cellulose Gmbh Low viscosity kraft fiber having reduced yellowing properties and methods of making and using the same
US9617686B2 (en) 2012-04-18 2017-04-11 Gp Cellulose Gmbh Use of surfactant to treat pulp and improve the incorporation of kraft pulp into fiber for the production of viscose and other secondary fiber products
US9951470B2 (en) 2013-03-15 2018-04-24 Gp Cellulose Gmbh Low viscosity kraft fiber having an enhanced carboxyl content and methods of making and using the same
WO2017220777A1 (en) * 2016-06-23 2017-12-28 Cellucomp Limited Method for preparing cellulose-containing particles

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