Classifications

• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H25/00—After-treatment of paper not provided for in groups D21H17/00 - D21H23/00
  • D21H25/02—Chemical or biochemical treatment
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
  • D06M11/00—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with inorganic substances or complexes thereof; Such treatment combined with mechanical treatment, e.g. mercerising
  • D06M11/58—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with inorganic substances or complexes thereof; Such treatment combined with mechanical treatment, e.g. mercerising with nitrogen or compounds thereof, e.g. with nitrides
  • D06M11/64—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with inorganic substances or complexes thereof; Such treatment combined with mechanical treatment, e.g. mercerising with nitrogen or compounds thereof, e.g. with nitrides with nitrogen oxides; with oxyacids of nitrogen or their salts
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H5/00—Special paper or cardboard not otherwise provided for
  • D21H5/12—Special paper or cardboard not otherwise provided for characterised by the use of special fibrous materials
  • D21H5/1272—Special paper or cardboard not otherwise provided for characterised by the use of special fibrous materials of fibres which can be physically or chemically modified during or after web formation
  • D21H5/1281—Special paper or cardboard not otherwise provided for characterised by the use of special fibrous materials of fibres which can be physically or chemically modified during or after web formation by chemical treatment
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
  • Y10T428/2913—Rod, strand, filament or fiber
  • Y10T428/2933—Coated or with bond, impregnation or core
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
  • Y10T428/2913—Rod, strand, filament or fiber
  • Y10T428/2933—Coated or with bond, impregnation or core
  • Y10T428/2964—Artificial fiber or filament
  • Y10T428/2965—Cellulosic

Definitions

• the present invention relates to a new process for the interfiber bonding of such cellulosic fibrous webs as paper and textiles.
• the process of the invention is particularly applicable to the production of paper having increased wet strength and to the production of vegetable parchments from parchment paper stock.
• the thus treated cellulosic fibrous web is then removed from contact with the DMSO-NO solution, and the web is washed to remove the solution and then is dried to obtain a product having high wet strength. If the fibers are compacted while in contact with the DMSO-NO solution the finished paper can be made low in porosity. A highly porous paper, if not compacted, can be increased in wet strength without loss of its porosity.
• the optimum length of time for the treatment of the fibrous web depends not only upon the concentration of N0 in the DMSO solution and the temperature of this solution but also upon the nature of the web being treated and the type of product being produced.
• a typical parchment paper stock is treated in accordance with our invention for about 1'20 seconds with a DMSO solution containing about 15% by weight N0 at a temperature of about 60 F.
• Any increase (or decrease) from said median concentration of 15% N0 or any decrease (or increase) from said median temperature of 60 F. should be accompanied by a corresponding: increase (or decrease) in said median time of seconds.
• the thus treated cellulosic Web normally requires no further treatment other than washing and drying, it is sometimes desirable to press or compact the treated web prior to washing the web in order to obtain a more tightly bonded and less porous product.
• the cellulosic fibrous webs that may be treated in accordance with our new process include such relatively thin and porous Webs as the paper stock employed in the manufacture of tea bags and the like, and such relatively thick and compact webs as the paper stock employed in the manufacture of vegetable parchment.
• Woven or nonwoven cellulose (i.e. cotton or rayon) textiles may also be treated in accordance with the practice of our invention to enhance the wet strength and stiffness and to reduce the porosity of the finished textile product.
• treatment of the cellulosic fibrous webs with a solution of N in DMSO under the conditions herein specified results in the creation of interfiber bonds between the individual fibers of cellulose.
• the interfiber bonding is due, we believe, to the swelling and softening of the individual fibers as a result of the treatment with the aforesaid solution, the increased contact between fibers 'While swollen, and the deswelling of the bonded fibers during the washing and drying steps of the process.
• the finished cellulosic fibrous webs will, when treated in accordance with the practice of our invention, have increased wet strength, increased dimensional stability and stiffness and, if desired, decreased porosity as hereinafter more fully described.
• Pure DMSO is a clear, colorless hygroscopic liquid having a boiling point of 189 C. and a melting point of 185 C. at atmospheric pressure. At ambient temperature and atmospheric pressure it will dissolve up to about 30% by weight of gaseous nitrogen dioxide to form a hydroscopic dark brown liquid of relatively low viscosity.
• the N0 and DMSO solution used in the practice of our in vention is prepared by bubbling gaseous N0 into liquid DMSO while excluding excess atmospheric moisture until a solution containing the desired concentration of N0 is obtained. Once formed, the solution is preferably used as soon as possible, but if storage is required, it is preferably cooled to about C. in order to avoid undesirable evolution of N0 and the solution should be kept in a sealed container to exclude atmospheric moisture which it readily absorbs.
• the cellulosic fibrous web is treated with the DMSO- N0 solution for the prescribed P riod of time, preferably by immersing the web in the solution, and then is washed with water or alcohol or some other liquid in which the treatment solution will dissolve and which is inert with respect to cellulose, and the washed Web is dried in a conventional dryer to obtain the desired finished product.
• the cellulosic webs can be immersed in the treatment solution either batchwise in the form of relatively small individual sheets or continuously by the use of conventional continuous treatment apparatus which unrolls, treats, washes, dries, and re-rolls extended lengths of the web.
• the cellulosic web can be treated with the DMSO-NO solution by padding the solution onto the web or otherwise impregnating the web with the solution for the required length of time.
• each treated sheet removed from the DMSO-NO solution is advantageously placed between sheets of an inert plastic film, such as Teflon, and the sheet is then passed through a pair of wringer rollers to effect the desired compaction of the wet sheet.
• the thus compacted sheet is then washed and dried in the usual manner.
• the roll compaction of the treated Web is readily accomplished with existing continuous paper treatment apparatus.
• the treatment of the cellulosic web with the DMSO-NO solution should be carried out in the presence of about 0.2 to 1.0% by weight water.
• the water may be present either in the solution or in the cellulosic web or in both. In practice it is preferred to maintain this small but critical amount of water present during the treatment step by pre-conditioning the cellulosic web in a humidifier-dryer so that the web contains about 4% to 8% moisture prior to treatment with the essentially anhydrous DMSO-NO solution.
• the length of time of the treatment of the cellulosic web with the DMSO- N0 solution will, in general, be within the range of from about 10 to 300 seconds. Within this general range the time of treatment is dependent upon and must be coordinated with a number of variable factors including the concentration of N0 in the DMSO-NO solution, the temperature at which the treatment is carried out, the nature of the cellulosic web being treated, and the type of product being prepared therefrom.
• the DMSO solution can contain from about 3% to 30% by weight N0 the higher concentrations of N0 paradoxically requiring longer periods of treatment to obtain the same degree of interfiber bonding for a given cellulosic web at a given temperature.
• the treatment of cellulosic fibrous webs in accordance with our invention requires that the web be treated with a DMSO-NO solution containing between 3% to 30% by weight N0 for a period of time of between 10 to 300 seconds and at a temperature of between 40 to 80 F.
• the time of treatment should be relatively short (say, from 10 to 30 seconds), whereas when the concentration of N0 in the solution is relatively high (for example, 20% to 30% by weight N0 the time of treatment is normally relatively much longer (say, from 4 to 5 minutes).
• the treatment of a certain cellulosic paper stock with a 15% NO -DMSO solution might require seconds to obtain the optimum degree of wet strength at a temperature of 60 R, whereas it might require seconds to obtain the same degree of wet strength at 40 F. and only 30 seconds at 80 F.
• EXAMPLE 3 Paper stock intended to be used in a zinc chloride Vulcanizing process was obtained from the manufacturer (National Vulcanized Fibre Company). The paper stock Samples of the same vulcanizing paper stock empolyed in Example 3 were treated with .DMSO-NO solutions at various concentrations and for various periods of time was of low strength and was unsized. Samples of the paper 75 as before. The treated sheets were rolled after being immersed in the solution in order to compact the treated fibers. The results of this treatment are reported in the following table:
• the samples were placed in wire holders and were dipped for measured periods of time in a solution of DMSO containing the desired quantity of nitrogen dioxide. Each sheet of treated paper was then removed from the solution, placed between two thin sheets of Teflon, and passed through wringer rolls. The rolled sheet was then washed with water for 10 to 20 minutes before drying at room temperature.
• the temperature of the DMSO-NO solution was about 70 F., except for one sample treated at 80 F. and one sample treated at 86 F. The sample treated at 86 F. was too soft to handle.
• Table VI The results of this treatment are reported in Table VI which follows.
• the process of this invention may be used also to make the product known as vulcanized fiber, in which a plurality of paper layers are pressed together while in the swollen condition and form an adherent mass after the swelling agent has been washed out.
• paper sheets are impregnated either continuously or separately with the DMSO-NO solution, then brought together by squeezing rolls.
• the swollen fibers of adjoining sheets are thus brought into contact and form bonds similar to those between fibers in the same sheet.
• the combined board is immersed in water and washed these bonds unite the layers of paper into a dense, hard, stiff board usable for many industrial products.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Life Sciences & Earth Sciences (AREA)
• Biochemistry (AREA)
• Paper (AREA)
• Laminated Bodies (AREA)

Applications Claiming Priority (1)

Publications (1)

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Family Applications (1)

Country Status (5)

Cited By (7)

Citations (2)

• 1967
  • 1967-09-25 US US670404A patent/US3529925A/en not_active Expired - Lifetime
• 1968
  • 1968-06-17 GB GB1239642D patent/GB1239642A/en not_active Expired
  • 1968-06-27 SE SE08807/68A patent/SE352389B/xx unknown
  • 1968-07-03 NO NO2662/61*[A patent/NO124321B/no unknown
  • 1968-07-26 FR FR1576732D patent/FR1576732A/fr not_active Expired

Patent Citations (2)

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