US3446697A - Method of improving the drainage properties of high bark content wood pulp in the making of fiberboard - Google Patents

Method of improving the drainage properties of high bark content wood pulp in the making of fiberboard Download PDF

Info

Publication number
US3446697A
US3446697A US434309A US3446697DA US3446697A US 3446697 A US3446697 A US 3446697A US 434309 A US434309 A US 434309A US 3446697D A US3446697D A US 3446697DA US 3446697 A US3446697 A US 3446697A
Authority
US
United States
Prior art keywords
bark
fiberboard
heat treatment
making
drainage
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US434309A
Other languages
English (en)
Inventor
Folke N Alvang
Kurt A Nordgren
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Mo och Domsjo AB
Original Assignee
Mo och Domsjo AB
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Mo och Domsjo AB filed Critical Mo och Domsjo AB
Application granted granted Critical
Publication of US3446697A publication Critical patent/US3446697A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21B—FIBROUS RAW MATERIALS OR THEIR MECHANICAL TREATMENT
    • D21B1/00—Fibrous raw materials or their mechanical treatment
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21B—FIBROUS RAW MATERIALS OR THEIR MECHANICAL TREATMENT
    • D21B1/00—Fibrous raw materials or their mechanical treatment
    • D21B1/04—Fibrous raw materials or their mechanical treatment by dividing raw materials into small particles, e.g. fibres
    • D21B1/12—Fibrous raw materials or their mechanical treatment by dividing raw materials into small particles, e.g. fibres by wet methods, by the use of steam
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21J—FIBREBOARD; MANUFACTURE OF ARTICLES FROM CELLULOSIC FIBROUS SUSPENSIONS OR FROM PAPIER-MACHE
    • D21J1/00—Fibreboard

Definitions

  • This invention provides a process for treating high barkcontent pulp used in the manufacture of fiberboard from fibrous raw material to improve the drainage properties of the defibrated fibrous materials, by heat treating the defibrated fibers at a temperature of from about 60 to about 300 C. until the solids content of the fibrous material is within the range from about 30 to about 80 weight percent, and the drainage properties of the fibrous material after dilution with water for sheet formation are improved at least five defibrator seconds.
  • the present invention relates to a method of making fiberboard and other molded bodies from a bark-rich raw material and to an apparatus for carrying the method into practice.
  • fibrous materials obtained by defibration of bark-containing wood chips are used to a large extent.
  • the raw material sometimes after having been subjected to preheating by treatment with steam, is passed continuously through a grinding zone and is then sluiced or blown into a cyclone, where the relatively dry and hot stock is immediately precipitated by spraying with Water.
  • the defibrated raw material is usually subjected to screening and refining before it is sized and pumped to the sheet-forming machine.
  • a relatively extensive grinding or refining is required. This grinding results in lowered freeness, i.e.
  • Defibrator seconds refers to the draining capacity of the stock as measured in a freeness tester according to defibrator, in which a 10 liter sample of a stock suspension is allowed to run through a wire screen of special structure (see e.g. Pulp and Paper Manufacture, vol. 3, 1953, pages 606609, Manufacture and Testing of Paper and Board).
  • the present invention relates to a method of making fiberboard and other molded bodies from a raw material containing a high proportion of bark, in which the raw material, optionally after preheating in a preheater, is defibrated in a defibrating apparatus, to liberate the fibers, which method is free from the disadvantages referred to above.
  • the method enables fiberboard to be manufactured from raw materials of up to 100% bark without essentially lowering the drainage capacity of the treated material and without reduction of the properties of the final product as regards strength and surface smoothness.
  • the process comprises subjecting the fiber material obtained by defibration, prior to removal of water therefrom in a sheet-forming machine, at a solids content of at least 10% to a heat treatment at a temperature of '60 to 300 C. so that the solids content after said heat treatment is 30 to 80% and for a period of time such that the drainage proper-ties of the treated fibrous material on dilution with water in a conventional way are considerably improved.
  • the fibrous raw material used for making fiberboard in accordance with this invention can be of either organic or inorganic origin and can be mixed with up to 100% bark.
  • Suitable organic fibrous materials are lignocellulosic materials, such as, e.g. chips of various woods, such as pine, spruce, fir, birch or waste material from pulp manufacture or from sawmils, e.g. sawdust.
  • Suitable inorganic fibrous materials which can be used in accordance with this invention include e.g. asbestos.
  • the bark material used in this invention may be derived from bark of spruce, pine, fir, birch, aspen and other woods.
  • the method is particularly advantageous in connection with spruce bark.
  • the amount of bark in the starting material will suitably be between 20 and 100% by weight.
  • the invention is particularly advantageous for bark proportions exceeding 30% by weight and highly marked improvements as regards the drainage capacity of the treated raw materials are achieved when the proportion of bark exceeds 50% by weight.
  • the temperature at which the heat treatment in accordance with this invention is carried out depends on the specific working conditions used in the fiberboard manufacture process and the desired properties of the final product and will usually be from about C. to about 300 C. Preferably, the heat treatment will be carried out at a temperature of to 250 C.
  • temperatures within the range of to 200 C. are to be preferred.
  • the heat treatment can be carried out under normal pressure as well as elevated pressure. If the heat treatment is carried out under normal pressure, a temperature of 70 to C. will suitably be used, and if the material is preheated prior to defibration, such preheating being generally achieved by heating with stream of '8 to 15 kg. per sq. cm. pressure, such a temperature is obtained in the material if it passed after defibration through a short conduit into a vessel communicating with the ambient atmosphere. If the heat treatment is carried out under elevated pressure, a temperature of 100 to 300 C. will generally be employed, and the device wherein the heat treatment is carried out will then be without continuous communication with the ambient atmosphere.
  • the period of time for carrying out the heat treatment shall be such that the drainage capacity of treated material, upon dilution with water in a conventional manner, is considerably improved.
  • the minimum time in which the stock is to be heat treated to achieve a considerably improved drainage capacity is shortened. If a temperature of 300 C. is used, a heat treatment period of at least seconds is to be employed to achieve satisfactory results, while at 100 C. the corresponding minimum time is 60 seconds.
  • treatment temperatures of 70 and 100 C. which are preferably used for treatment at'atmospheric pressure the heat treatment should be carried out for a time of at least 1 minute, preferably at least 3 minutes.
  • the heat treatment should, of course, not be carried out so that a considerable drying of the fibers results.
  • the defibrated bark-containing stock which is to be heat-treated according to this invention usually has a solids content of to 80%, preferably 35-50%, and if steam is used as the heat transfer medium, drying of the fibrous material in the heat treatment process is avoided. The procedure is often facilitated, however, if the solids content at the start of the heat treatment is considerably below 80% and may then be allowed to rise toward that level, but preferably not above 65%.
  • the solids content of treated fibrous material should be within the range of from 30 to 80%.
  • the process of this invention can be combined with a refining step, which can be carried out before or, if desired, after the heat treatment step without considerably reducing the improved (1 rainage properties of the fibrous material.
  • a refining treatment always results in some reduction of the drainage properties, it should preferably be made prior to the heat treament. It will, of course, also be possible to subject the material to a heat-treatment both before and after any refining step.
  • the heat-treatment of this invention especially for treating lignocellulosic fibrous materials having a relatively low proportion of bark therein, is carried out at a very high temperature and for a relatively long period of time, the treatment may result in some reduction of the strength properties of the final products, but on the other hand other advantages are gained, such as improved sheet formation and in some cases improved water-repellent properties of the final product.
  • the strength properties are not of substantial importance, this may be of practical interest and may, per se, justifythe utilization of the invention even for proportions of bark which with regard to drainage capacity might be acceptable even in conventional treatment.
  • the invention is illustrated by the following example which shows the application of the invention to the manufacture of hardboard.
  • the invention is not limited to this example, however, but can be applied in all types of manufacture of fiberboard, plates and molded bodies from organic of inorganic fibrous materials containing a proportion of bark.
  • a suitable equipment for carrying the method of this invention into practice is shown diagrammatically on the accompanying drawings.
  • the defibrating apparatus wherein the raw material is defibrated in a well-known manner in the presence of steam, is shown at 1.
  • the defibrated raw material is blown as a suspension in steam into a cyclone 2 which has an upper outlet 3 for release of steam, if needed, and a lower material outlet 4.
  • the fibrous material precipitated in the cyclone 2 drops through the outlet 4 into a conveyor casing 5 and onto a conveyor belt 6 arranged therein, said belt conveying the material towards the casing outlet 7 through which it falls down into a stock bin 8 where it is diluted to a suitable consistency to be fed to the sheet-forming machine.
  • the speed of the conveyor 6 is controlled so that the material has a suitable residence time in the casing 5 to undergo the desired heat treatment.
  • the casing 5 has a heat insulation 9 to limit the temperature reduction of the material during the conveyance.
  • the steam liberated from the material can suitably be precipitated as liquid by injecting water through the nozzles 10.
  • the improvement which comprises heating, before addition of water, the defibrated fibrous material having a solids content of at least 10% at a temperature in the range from about to about 300 C. until (1) the solids content of the fibrous material is increased, if necessary, to within the range from about 30 to weight percent and (2) the drainage properties of the fibrous material, after dilution with water for sheet formation, are improved at least 5 defibrator seconds.
  • a method as in claim 1 iln which the bark material is pine bark.
  • a method as in claim 1 including the step of preheating the fibrous raw material prior to defibration thereof.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Wood Science & Technology (AREA)
  • Paper (AREA)
  • Dry Formation Of Fiberboard And The Like (AREA)
  • Fodder In General (AREA)
US434309A 1964-03-10 1965-02-23 Method of improving the drainage properties of high bark content wood pulp in the making of fiberboard Expired - Lifetime US3446697A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE298464 1964-03-10

Publications (1)

Publication Number Publication Date
US3446697A true US3446697A (en) 1969-05-27

Family

ID=20261141

Family Applications (1)

Application Number Title Priority Date Filing Date
US434309A Expired - Lifetime US3446697A (en) 1964-03-10 1965-02-23 Method of improving the drainage properties of high bark content wood pulp in the making of fiberboard

Country Status (8)

Country Link
US (1) US3446697A (enExample)
AT (1) AT264803B (enExample)
CH (1) CH441737A (enExample)
DE (1) DE1436947A1 (enExample)
FR (1) FR1426012A (enExample)
GB (1) GB1076124A (enExample)
NL (1) NL6502589A (enExample)
NO (1) NO118472B (enExample)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3907630A (en) * 1971-01-20 1975-09-23 Defibrator Ab Method of fiber board article production employing predrying of the ligno-cellulosic material prior to liquid suspension and article formation, and employing water recirculation
US4012279A (en) * 1973-12-28 1977-03-15 Stig Selander Process of producing pulp, for manufacture of fiberboard, in a closed backwater system
DE2749499A1 (de) * 1976-11-11 1978-05-24 Prb Sa Verfahren zur herstellung von hitzeverformbaren platten, nach dem verfahren hergestellte platten und ihre verwendung zur herstellung von formgegenstaenden
CN113459236A (zh) * 2020-03-31 2021-10-01 精工爱普生株式会社 纤维成形体制造用原料以及纤维成形体的制造方法

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2008892A (en) * 1932-03-29 1935-07-23 Defibrator Ab Method of manufacture of pulp
US2317394A (en) * 1939-11-18 1943-04-27 Masonite Corp Process for making hardboard
US2759837A (en) * 1952-10-13 1956-08-21 Weyerhaeuser Timber Co Process of forming molded cellulose products
US2870009A (en) * 1955-06-15 1959-01-20 Kamyr Ab Method and apparatus for the separation of liquids from cellulosic pulp

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2008892A (en) * 1932-03-29 1935-07-23 Defibrator Ab Method of manufacture of pulp
US2317394A (en) * 1939-11-18 1943-04-27 Masonite Corp Process for making hardboard
US2759837A (en) * 1952-10-13 1956-08-21 Weyerhaeuser Timber Co Process of forming molded cellulose products
US2870009A (en) * 1955-06-15 1959-01-20 Kamyr Ab Method and apparatus for the separation of liquids from cellulosic pulp

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3907630A (en) * 1971-01-20 1975-09-23 Defibrator Ab Method of fiber board article production employing predrying of the ligno-cellulosic material prior to liquid suspension and article formation, and employing water recirculation
US4012279A (en) * 1973-12-28 1977-03-15 Stig Selander Process of producing pulp, for manufacture of fiberboard, in a closed backwater system
DE2749499A1 (de) * 1976-11-11 1978-05-24 Prb Sa Verfahren zur herstellung von hitzeverformbaren platten, nach dem verfahren hergestellte platten und ihre verwendung zur herstellung von formgegenstaenden
CN113459236A (zh) * 2020-03-31 2021-10-01 精工爱普生株式会社 纤维成形体制造用原料以及纤维成形体的制造方法
EP3889348A1 (en) * 2020-03-31 2021-10-06 Seiko Epson Corporation Fiber-formed body producing raw material and fiber-formed body producing method

Also Published As

Publication number Publication date
FR1426012A (fr) 1966-01-24
CH441737A (de) 1967-08-15
NO118472B (enExample) 1969-12-29
NL6502589A (enExample) 1965-09-13
AT264803B (de) 1968-09-10
GB1076124A (en) 1967-07-19
DE1436947A1 (de) 1969-01-16

Similar Documents

Publication Publication Date Title
US4152197A (en) Process for preparing high-yield cellulose pulps by vapor phase pulping an unpulped portion of lignocellulosic material and a partially chemically pulped portion
US4087317A (en) High yield, low cost cellulosic pulp and hydrated gels therefrom
DE60208034T2 (de) Verfahren zur herstellung eines gebleichten tmp- oder ctmp zellstoffs
JPH09225908A (ja) 麦わらから繊維を製造する方法及びその繊維で製造されたボード製品
US4116758A (en) Method of producing high yield chemimechanical pulps
US3620911A (en) Wet depithing of a nonwoody lignocellulosic plant material
JPS61275489A (ja) 二段階含浸法による漂白したケミメカニカルおよびセミケミカル繊維パルプの製造法
US2047170A (en) Treatment of fibrous material
US3446697A (en) Method of improving the drainage properties of high bark content wood pulp in the making of fiberboard
EP0328533A1 (en) PROCESS FOR THE MANUFACTURE OF PRODUCTS CONTAINING FIBERS OF LIGNOCELLULOSIC MATERIAL.
US1850832A (en) Process of separating wood fibers
CA2440789C (en) Method for producing pulp
PL79407B1 (enExample)
US3224925A (en) Fibrous products from barking waste
FI83238B (fi) Foerfarande foer framstaellning av cellulosa.
US4221630A (en) Wet method of preparing fiberboard products in a substantially closed and balanced white water system
US3073737A (en) Wood pulp and process for producing same
US3165436A (en) Continuous impregnating and pulping process
US3262839A (en) Neutral to weakly alkaline sulfite process for the extraction of cellulose from cellulosic material
JPH01501953A (ja) 機械パルプを処理する方法
EP0030778A1 (en) Process for the formation of refiner pulp
US1794174A (en) Method of preparing ground wood pulp
US3202569A (en) Cold caustic fiberboard manufacture
US2361639A (en) Process for defibering lignocellulosic materials
GB2035839A (en) A method of making paper pulp stock, and stock made by the method