Classifications

• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21G—CALENDERS; ACCESSORIES FOR PAPER-MAKING MACHINES
  • D21G1/00—Calenders; Smoothing apparatus
  • D21G1/02—Rolls; Their bearings
  • D21G1/0233—Soft rolls
  • D21G1/024—Soft rolls formed from a plurality of compacted disc elements or from a spirally-wound band
• • 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
  • D21H13/00—Pulp or paper, comprising synthetic cellulose or non-cellulose fibres or web-forming material
  • D21H13/36—Inorganic fibres or flakes
  • D21H13/46—Non-siliceous fibres, e.g. from metal oxides
  • D21H13/50—Carbon fibres
• • 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
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S428/00—Stock material or miscellaneous articles
  • Y10S428/906—Roll or coil
• • 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
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S428/00—Stock material or miscellaneous articles
  • Y10S428/909—Resilient layer, e.g. printer's blanket
• • 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
  • Y10T428/2918—Rod, strand, filament or fiber including free carbon or carbide or therewith [not as steel]
• • 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
  • Y10T442/00—Fabric [woven, knitted, or nonwoven textile or cloth, etc.]
  • Y10T442/50—FELT FABRIC
  • Y10T442/51—From natural organic fiber [e.g., wool, etc.]
  • Y10T442/53—Including particulate material other than fiber

Definitions

• the invention relates to a fiber material for the production of covers for elastic smoothing rollers, for example super calenders for paper satinizing, and elastic smoothing rollers, which are provided with a cover made of such a compressed fiber material.
• super calenders consist of a set of successive rolls, each forming a press nip, which essentially alternate between hard steel rolls and rolls exist with a more elastic jacket that deforms under pressure in the press nip. Due to the resulting speed difference and the temperature generated by the flexing of the elastic rollers the paper that is moved back and forth through the individual press nips is smoothed.
• a special fiber material has become established as the material for the jacket or cover of the elastic rolls of supercalenders, which is pressed onto the roll cores under high pressures of about 500 to 600 bar and is then cylindrically turned and polished.
• Cellulose fibers namely cotton sinters
• cotton sinters are primarily used as the fiber material.
• other fiber materials can also be added to these cellulose fibers.
• the European standard cover for elastic calender rolls consists of 80% cotton and 20% wool. Roller covers with up to 50% asbestos fibers are also used for special purposes.
• the fiber material used for covering elastic smoothing rolls or calender rolls which for the most part consists mainly of cotton fibers with possibly a percentage of wool, is used in the form of paper made from this material, which is produced by conventional paper production processes on Fourdrinier paper machines.
• Octagonal or round disks with a central opening for the roller core are cut from the paper, which are then stacked on the roller core and pressed together with the pressures mentioned up to 600 bar in the axial direction.
• the rolls prepared in this way are then turned to an exact dimension and polished.
• the fiber material for the roll cover in the form of a paper.
• Manufacturing processes are also known in which the fiber material, for example carded cotton fiber, is pressed onto the roller core in a different manner.
• calender roll papers are used almost exclusively for re-covering the elastic smoothing rolls.
• calender roll covers with up to 50% asbestos fibers are used because these fibers are better able to withstand the high temperatures that occur.
• Such roller covers are not so favorable in their other technological properties. Therefore, further attempts have been made to find heat-resistant fiber material for calender roll covers, which has the same technological properties as the cotton covers. So far, however, these efforts have not been successful.
• the aim of the present invention was to solve the problem by better heat dissipation from the roll cover without impairing the technological properties of the previously proven fiber materials for elastic smooth roll covers.
• fiber material when one speaks of "fiber material” in this context, it means the entire material for the roll cover, which is generally made available in the form of a paper.
• fibrous material means the actual fibrous substances in the fiber material which, together with possibly other additives, form the fiber material as a material for the roll cover.
• proportions of carbon fiber of the total fibrous material in the range from about 1.5 to 15% by weight are possible, preferably from about 3 to 12% by weight.
• a proportion of 2% by weight a noticeable effect can be expected depending on the other conditions and additives.
• To g abemengen about 10 wt .-% are indeed possible, but no longer lead to a significant improvement of the effect as it is necessary under operating conditions to eliminate the temperature-staues under the roll surface.
• carbon fiber is relatively expensive, higher additions would prove to be at least disadvantageous in terms of costs.
• care must be taken to ensure that it mixes sufficiently with the other fiber materials in the material suspension.
• Carbon fibers which float in aqueous suspension or which are essentially hydrophobic are less suitable in so far as the fiber material is previously produced in the form of a paper in a normal paper production process.
• a carbon fiber based on polyacrylonitrile has been used proven to be processable.
• the fiber lengths of the carbon fibers should expediently be of the order of magnitude of the prevailing fiber lengths of the other fiber materials in order to be able to produce a suspension which is as homogeneous as possible.
• the fiber thickness should also be of the same order of magnitude as the rest of the fibrous material, so that a mutual felting of the fibers can occur during paper production.
• carbon fibers with a length of 3 mm and a diameter of 5 to 10 ⁇ m could be processed successfully with cotton sinters which have a length of 2 to 3 mm and a diameter of 17 to 27 ⁇ m.
• the thermal conductivity properties of the fiber material according to the invention can also be improved by adding an electrically conductive carbon black to the fiber material. Additions of 0.5 to 10% by weight, based on the total fiber material, are possible. However, the effect of the addition of carbon black based on an equal weight fraction is significantly less compared to the carbon fibers.
• the use of carbon black in papermaking also has the disadvantage that this non-fibrous material is less retained on the paper machine screen and therefore puts a strain on the water cycle.
• the carbon fiber also contributes to the strength and elasticity of the paper. A possible addition of carbon black with appropriate adjustment of the carbon fiber content is to be determined for the individual case from a technological and cost point of view.
• preferred papers according to the invention consist of a fibrous material consisting essentially of exclusively cotton fibers or of cotton sinter and wool in weight ratios of 7 to 3 to 9 to 1.
• the invention also relates to the use of the new fiber material for the production of covers for elastic Smoothing rolls, in particular calender rolls, as well as elastic smoothing rolls, which are provided with a cover made of a compressed fiber material, which contains a proportion of carbon fibers, preferably in the amounts as previously described for the paper.
• the reference of the rollers according to the invention does not necessarily have to be derived from a paper. The addition of soot is also possible here.
• the alternating loading of the test cube is carried out until the area under the plunger burns, a so-called "burn-out" occurs.
• the ram test conditions are at a load of 50 kp and a frequency of 50 Hz, corresponding to an alternating pressure of 5.0 bar.
• a service life of a sample cube made of conventional material of 20 minutes is rated as good, that of only 10 minutes as poor.
• the temperature difference between sensors 1 and 2 is around 90 ° C. at the end of the test in conventional calender roll papers. Since the temperature gradient between the two sensors is a measure of the heat dissipation of the sample, this value already indicates the poor heat dissipation of cellulose-based calender roll papers, which leads to the temperature build-up mentioned and ultimately to the burn-out below the sample surface.
• a test cube was again produced under the same conditions as described in Example 1, but the load on the plunger was doubled. With conventional calender roll papers, a burn-out occurs within a few minutes under this load. In the test paper according to the invention, no burnout occurred even under these more severe conditions. A burn-out could only be achieved after a standing time of 55 minutes after an additional increase in the exercise frequency.
• the temperatures measured on the sensors were 216 ° C (sensor 1) and 152 ° C (sensor 2).
• a calender roll paper made of 90% by weight of cotton sinter and 10% by weight of carbon fibers of the type mentioned in Example 1 was used on a commercial paper machine at a machine speed of about 80 to 90 m / min with a basis weight of about 160 to 170 g / m 2 produced.
• Previous tests with elastic roller covers made of cotton resulted in service lives for the rollers of less than 2 hours.
• the roller with the cover according to the invention could be run over a production time of 526 hours. A matt surface then appeared and when the cover was subsequently split off, it was found that the roller was completely burned. Contrary to this phenomenon, most conventional rollers have to be replaced due to local burns. Use until the material is completely burned is never achieved. This indicates that the surface damage that can never be avoided during operation of a calender, which leads to local heating and local burnout, is hardly of any influence in the roller according to the invention, because the local temperature increases are apparently better derived there and distributed over the entire roller.
• covers for elastic calender rolls can be produced with the fiber material according to the invention, which are considerably superior to the previously known roll covers with regard to their stability, the addition of the carbon fibers also having a technologically favorable effect on the roll work.

Landscapes

• Chemical & Material Sciences (AREA)
• Inorganic Chemistry (AREA)
• Paper (AREA)
• Rolls And Other Rotary Bodies (AREA)
• Manufacturing Of Magnetic Record Carriers (AREA)
• Treatment Of Fiber Materials (AREA)
• Spinning Methods And Devices For Manufacturing Artificial Fibers (AREA)
• Preliminary Treatment Of Fibers (AREA)
• Immobilizing And Processing Of Enzymes And Microorganisms (AREA)
• Reinforced Plastic Materials (AREA)
• Macromolecular Compounds Obtained By Forming Nitrogen-Containing Linkages In General (AREA)

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Applications Claiming Priority (2)

Publications (2)

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Citations (7)

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• 1983
  • 1983-02-04 DE DE19833303703 patent/DE3303703A1/de not_active Withdrawn
• 1984
  • 1984-01-31 AU AU24953/84A patent/AU568334B2/en not_active Ceased
  • 1984-01-31 DE DE8484100947T patent/DE3467200D1/de not_active Expired
  • 1984-01-31 WO PCT/DE1984/000025 patent/WO1984003113A1/fr not_active Ceased
  • 1984-01-31 EP EP84100947A patent/EP0131083B1/fr not_active Expired
  • 1984-01-31 AT AT84100947T patent/ATE30609T1/de not_active IP Right Cessation
  • 1984-01-31 JP JP59500768A patent/JPS60500420A/ja active Pending
  • 1984-02-01 ZA ZA84746A patent/ZA84746B/xx unknown
  • 1984-02-03 NZ NZ207040A patent/NZ207040A/en unknown
  • 1984-02-03 CA CA000446737A patent/CA1254424A/fr not_active Expired
  • 1984-08-27 FI FI843370A patent/FI74088C/fi not_active IP Right Cessation
• 1985
  • 1985-12-20 US US06/814,540 patent/US4659616A/en not_active Expired - Fee Related

Patent Citations (7)

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