Classifications

• • 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
  • D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
  • D21C9/001—Modification of pulp properties
  • D21C9/002—Modification of pulp properties by chemical means; preparation of dewatered pulp, e.g. in sheet or bulk form, containing special additives

Definitions

• This invention relates to the manufacture of cellulose pulp; more particularly it concerns, and
• the general procedure of converting raw fibre into finished paper and paper products comprises two successive processes, which in commercial reality are distinct arts.
• the first of these usually includes breaking up the raw fibrous material, such as wood of various sorts, other vegetable substances, or rags, and producing by grinding or by suitable chemical digestion, a liquid suspension of the fibres and masses of fibre. Concentration of the suspension in many cases involves reducing it to a nonno fluid state, i. e., a dried or semi-dried condition;
• the resulting product, cellulose pulp may thus be stored, shipped, or otherwise commercially handled without inconvenience.
• the second general process is that of actual paper manufacture, a distinct art, frequently practised, for important economic reasons, at places distant from the remote localities where pulp is more conveniently produced.
• Cellulose pulp, in dried or semi-dried condition is accordingly an important commercial product for the paper manufacturer, who subjects it to the several steps of beating, refining, and other mechanical or chemical treatment, together with ultimate fabrication of a Fourdrinier, vat, or like machine, to produce paper and board of various sorts.
• beater sizing carried out during paper 5 manufacture, comprises the treatment of pulp in the beaters or refiners with one or usually more applied substances.
• the sizing agent most commonly used is rosin, although beater sizing with emulsified waxes or oils, along with resin and in 10 some cases without the latter, has been proposed.
• the acidity or pH of the stock In effecting precipitation with .acid substances,-for example, with aluminum sulfate,the acidity or pH of the stock must be rigidly supervised and continually ad- 30 justed, in order on the one hand to produce a strong fixation of the precipitate on the fibres, and on the other hand to avoid injuring the fibres or the machinery employed.
• the various dispersions and solutions for sizing and fixation must be carefully prepared, and the application of such materials during beating or refining must be accurately timed, in order to obtain satisfactory 40 results.
• the necessary acidity of the stock is particularly inconvenient: it is detrimental to machinery, and often likely to cause actual damage; it seriously interferes with the beating of the pulp, a step more effectively and 50 I satisfactorily performed if the suspension is neutral or alkaline.
• a paramount object of the present invention is to minimize one or more of the abovementioned and other difficulties incidental to sizing operations now used in paper manufacture; and a further important object is to eliminate sizing operations from the general process of actual paper manufacture, while at the same time providing for the production of satisfactory sized paper and like articles.
• the invention thus seeks to avoid the careful supervision which paper manufacturers must exercise over the usual sizing operations, as well as to avert detrimental effects of the latter on machinery and/or on the quality of the finished and sized paper product.
• an important feature of the invention resides in the provision of a new article of manufacture,'comprising an improved form of unbeaten and unrefined cellulose pulp, which, for example, in nonfiuid condition particularly convenient for commercial handling and use according to present practice in the industry, has incorporated with it certain material or materials found to have suitable sizing properties.
• An essential characteristic of such pulp is that the sizing substance or substances will remain affixed to the fibres during working of the pulp in paper manufacture,-i. e., during the various steps of breaking up, beating, refining, and diluting, as well as fabrication on the Fourdrinier or vat machine,-all without close supervision or attention on the part of the paper manufacturer.
• the purposes of the invention are effectively served by providing a new article of manufacture of the sort described, and likewise by providing simple, satisfactory, and economical procedure for introducing compositions of sizing character during pulp-making operations.
• melted paraffin may conveniently be poured on the surface of one of the first drying cylinders, so as to dispose it uniformly thereon; the sheet of pulp then receives a layer of parafl'in as it passes the cylinder, and the action of subsequent drying cylinders further serves to distribute the paraffin uniformly and to incorporate it into the body of the pulp sheet,in fact, it is believed, into the individual cellulose fibres.
• Procedure of this character obviates the use of carefully regulated dispersions, precipitating solutions, and the like, in paper manufacture; in fact, the paper manufacturer need employ no sizing operation whatever.
• the resulting new product comprises a body of unbeaten and unrefined cellulose pulp, conveniently in non-fluid sheet'form, having paraflin incorporated therein as a sizing composition.
• This pre-sized pulp can be readily shipped, stored, or otherwise handled, and it may be employed by the paper manufacturer for making sized paper of particularly strong, white and thoroughly satisfactory character.
• Stock made from the pulp can within reasonable limits be acid, neutral or alkaline, without affecting the quality of the ultimate sizing on the paper, and in fact, mechanical working of the pulp, such as beating and refining as well as subsequent dilution of the stock, serves automatically to improve and enhance not only the distribution of paraffin throughout the material, but also its association in proper sizing relation with the cellulose fibres.
• presized pulp has satisfactorily been made containfrom this pulp, it is generally necessary to employ a quantity of ordinary unsized pulp along with the sized product, so that the resulting paper will contain the proper amount of paraffin for efficient and satisfactory sizing.
• the two pulps when broken up and put in water suspension, will be thoroughly mixed during the processes of beating and/or refining, and also during subsequent dilution of the stock and operation of the paper machine, it having been found that a thorough impregnation of all fibres as needed for sizing is thereby effected.
• the pre-sized pulp may be usefully made with paraffin in smaller proportions, for. instance, as will be directly needed in the paper to be manufactured, it is particularly advantageous to introduce paraffin into the pulp in quantities of the order noted, or in some cases somewhat more; on the one hand, such amounts of paraffin can be effectively incorporated into the fibres, and on the other hand, since unsized pulp may be added as needed, the sizing operations can be restricted, if desired, to certain batches or certain kinds of pulp. Thus, for instance, where paper is to be made from a mixture of long and short fibres, or of mechanical and chemical pulps, or of otherwise differing materials, only one variety of pulp, or part of it, need be of pre-sized character.
• paramn has been found peculiarly satisfactory as a pre-sizing material for pulp according to the present invention, by reason, for example, of its durability, whiteness, cheapness, and capacity for remaining affixed to the cellulose fibres, other substances may be used in many cases, either alone or in combination with paraffin.
• Such other substances are generally waxes, and include the various hydrocarbons, other similar waxes, and in some instances materials such as stearic acid, and the like.
• waxes and like substances which have the following properties: a good white color or lack of other color, insolubility in water and substantial water-resistance, a melting point below about 100 C.-, and preferably between and 90 C., and adhesiveness, conveniently affording sufiicient adherence to cellulose fibres so that the sizing substance remains aflixed thereto if the pulp is thereafter put in suspension in water.
• paraffin or like material can be applied, for example, in the state of an emulsion,prepa'red according to any well-known method of producing an aqueous paraffin emulsion,which may be added to the pulp as it goes through the pulp machine, -or conveniently, before it is brought to such machine.
• sizing compositions of the character contemplated by the invention may be pulverized or otherwise comminuted, and thoroughly mixed with the pulp during or prior to its passage through the pulp machine.
• pre-sizing methods may often be employed to great practical advantage, as by applying the paraffin or like material at a corresponding stage in pulp-manufacturing operations-conveniently, for instance, by introducing an aqueous emulsion of paraflin into the pulp at or before the time that the latter passes through such concentrators or concentrating devices as are used to receive the cellulose from a chemical or other digesting treatment and reduce it to pulp of suitable consistency for paper-making operation.
• the new commercial product of the invention i. e., pre-sized unbeaten and unrefined pulp of non-fluid nature
• the new commercial product of the invention is of a particularly superior, character when made with cellulose suspensions that have been directly prepared from wood or like vegetable substances, as by one of the chemical processes; and that pre-sizing methods are likewise eminently practical and valuable as performed on such cellulose.
• Other pulps can be produced in presized form, with highly satisfactory results in a number of cases, and the procedures described are useful in the manufacture of many kinds of cellulose pulp, to be employed ultimately in making any of a wide variety of sized papers and. sized paper products.

Landscapes

• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Wood Science & Technology (AREA)
• Paper (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=8975346

Family Applications (1)

Country Status (6)

Cited By (4)

Families Citing this family (2)

• 0
  • NL NL38055D patent/NL38055C/xx active
  • BE BE395323D patent/BE395323A/xx unknown
• 1932
  • 1932-04-22 FR FR750032D patent/FR750032A/fr not_active Expired
  • 1932-05-09 FR FR42741D patent/FR42741E/fr not_active Expired
  • 1932-08-02 GB GB21676/32A patent/GB404386A/en not_active Expired
  • 1932-08-11 DE DEP65808D patent/DE607403C/de not_active Expired
  • 1932-12-15 US US647414A patent/US2061935A/en not_active Expired - Lifetime
• 1934
  • 1934-10-03 FR FR45945D patent/FR45945E/fr not_active Expired

Also Published As

Similar Documents